JP3641940B2 - Printing apparatus, printing method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for printing an image while performing raster formation and sub-scanning, and more particularly to a technique for expanding an area on which an image is recorded by the printing.
[0002]
[Prior art]
As a printer capable of performing sub-scanning while forming a raster and printing an image according to the image data input on the print medium, a line printer that does not involve main scanning in which the head reciprocates when the raster is formed, There are serial scan type printers and drum scan type printers that form a raster by main scanning the head. In this type of printer (particularly an inkjet printer), a nozzle array having a plurality of nozzles in the sub-scanning direction for the same color is generally used to increase the printing speed. In recent years, in order to increase the printing speed, the number of nozzles in the sub-scanning direction tends to increase, and as a result, the nozzle array tends to increase in size.
[0003]
In such a printer, as one of recording methods for improving image quality, there is a technique called “interlace method” disclosed in US Pat. No. 4,198,642, Japanese Patent Laid-Open No. 53-2040, and the like. FIG. 43 is an explanatory diagram showing an example of an interlace method. First, various parameters used in the following description will be described. In the example of FIG. 43, the number N of nozzles used for dot formation is three. The nozzle pitch k [dot] in FIG. 43 indicates how many nozzle pitches (dot pitch w) are in the recording head. In the example of FIG. 43, k = 2. In the example of FIG. 43, since each raster is embedded in one main scan, the number of scan repetitions indicating how many main scans each main scan line (hereinafter referred to as “raster”) is embedded with dots. s is 1 time. As will be described later, when the number of scan repetitions s is 2 or more, in each main scan, dots are intermittently formed along the main scan direction. L in FIG. 43 means the paper feed amount in the sub-scan, and corresponds to 3 rasters in this example.
[0004]
In FIG. 43, circles including two-digit numbers indicate dot recording positions. Among the two-digit numbers in the circle, the number on the left side indicates the nozzle number, and the number on the right side indicates the printing order (how many times the main scanning was recorded).
[0005]
In the interlaced recording shown in FIG. 43, dots of each raster are formed by the second nozzle and the third nozzle in the first main scan. The first nozzle does not form dots. Next, as shown in FIG. 43, after paper feeding for three rasters is performed, each raster is formed using the first nozzle to the third nozzle while performing the second main scan. Thereafter, an image is recorded by repeatedly executing paper feeding for three rasters and forming a raster by main scanning in the same manner. As is apparent from the above, the raster was not formed by the first nozzle in the first main scan because the raster adjacent to the raster cannot be formed in the second and subsequent main scans.
[0006]
The interlace method is a method of recording an image while intermittently forming rasters in the sub-scanning direction. This interlace method has an advantage that variations in nozzle pitch, ink ejection characteristics, and the like can be dispersed on a recorded image. Therefore, even if there are variations in the nozzle pitch and ejection characteristics, it is possible to alleviate these effects and improve the image quality. In FIG. 43, the case where each raster is formed by a single main scan at a specific nozzle pitch has been described. Is possible.
[0007]
The interlace method is a very effective recording method from the viewpoint of improving the image quality as described above. For example, when recording is started from the upper end of the paper, the image is recorded at the lower end where the image is finally recorded. An area that cannot be recorded inevitably occurs. FIG. 44 is an explanatory diagram showing a state in which an image is recorded by an interlace method with a feed amount of 7 rasters by a head including 7 nozzles having a nozzle pitch corresponding to 4 rasters. 44, the symbols P1, P2,... Mean the first, second,... Main scanning, respectively, and the encircled numbers indicate the nozzle sub-scanning direction in each main scanning. Indicates the position. The numbers are nozzle numbers. The number shown in the form of “RN =” is a raster number assigned to each raster for convenience of explanation. If each raster is formed by main scanning at each nozzle position, it can be seen that an image is formed by the interlace method.
[0008]
FIG. 44 shows the state of six main scans near the lower end of the paper. That is, the No. 7 nozzle in the main scan P6 indicates the lower limit position where the nozzle can be positioned due to the paper feed mechanism. Here, the paper feeding mechanism will be described with reference to FIG.
[0009]
In general, a paper feed mechanism of a printer is configured by two sets of rollers on a print medium supply side and a discharge side. As the print medium supply side rotor, there are a paper feed roller 25a and a driven roller 25b shown in FIG. 4, and as the discharge side rollers, there are a paper discharge roller 27a and a serrated roller 27b. In general, the paper feed accuracy in the sub-scanning is guaranteed by either the paper supply side roller or the discharge side roller. For example, assuming that the paper feed accuracy is guaranteed by the roller on the paper feed side, the sub-scan is performed with an accuracy sufficient to record an image because the lower end of the print medium is fed from the paper feed roller 25a and the driven roller 25b. The time to come off is the limit. At this time, the distance from the lower end of the head to the lower end of the print medium is determined by the positions of the paper feed roller 25a and the driven roller 25b, and is a distance a as shown in FIG. The seventh nozzle in the main scanning P6 in FIG. 44 corresponds to a state in which the nozzle is at such a limit position.
[0010]
In such a case, if an image is recorded with a fixed feed amount corresponding to 7 rasters, as shown in FIG. 44, a missing raster, that is, a portion where no raster is formed occurs (see raster number-10). For this reason, when the interlace method is adopted, an image is formed only up to the area A shown in FIG. Depending on the combination of the paper feed amounts in the interlace method, there is a possibility that an image can be formed only up to the position of the first nozzle in the main scan P6 (region of RN ≦ −17). As shown in FIG. 4, if the width of the head in the sub-scanning direction is h, in this case, a portion corresponding to “a + h” from the lower end of the print medium forms an inevitable margin, that is, an image. This is an area that cannot be obtained. Actually, it is necessary to allow for a margin for an error or the like in the paper feed, so the margin is further increased.
[0011]
[Problems to be solved by the invention]
Such margins cannot be overlooked when the nozzle array is becoming larger in recent years, regardless of whether the nozzle array is relatively small, that is, when the width h in FIG. 4 is relatively small. I came. Such a large margin greatly impairs the value of the printer due to high image quality and high printing speed.
[0012]
After the recording medium is removed from the paper feed roller that can ensure the sub-scan paper feed accuracy, the paper output side is less accurate than when the paper is clamped between the paper feed rollers. It is possible to perform sub-scanning with these rollers. Therefore, a method of reducing the above-mentioned margin part by recording an image while performing such paper feeding is also conceivable. For example, if the raster is formed while performing the main scanning P7 shown in FIG. 44, it is understood that the raster omission described above can be eliminated and the image recording area is enlarged. In this case, in principle, an image can be recorded up to the lower limit of the sheet.
[0013]
However, the sub-scanning recording method with low paper feed accuracy naturally reduces the image quality. FIGS. 45 and 46 show how the image quality deteriorates when the paper feed accuracy is lowered. Both of these figures show a dot row recorded in a certain area. FIG. 45 shows the state of dots when sub-scanning accuracy is ensured. In order to avoid the complexity of the figure, the state of dots is shown by alternately using solid lines and broken lines for each raster. As shown in FIG. 45, the dots are arranged at a uniform recording pitch in both the main scanning direction and the sub-scanning direction. In general, since the dots are formed to have a size that slightly overlaps with adjacent dots, in such a case, the dots can fill up a predetermined area as shown in FIG.
[0014]
On the other hand, FIG. 46 shows the state of dots when the sub-scanning accuracy is low. Even in this case, since the accuracy of main scanning is ensured, dots are formed at a constant recording pitch in the main scanning direction. However, the recording pitch in the sub-scanning direction varies depending on the sub-scanning error. As a result, for example, there are a portion where the dots are sparse in the sub-scanning direction like the region a1 and a portion where the dots are dense like the region a2. These sparseness and density are perceived as shading that is not present in the image data, thereby degrading the image quality. In some cases, a portion where dots are not formed, such as a region a3 in FIG. 46, so-called white spots may occur. In general, vision is very sensitive to such white spots, and the occurrence of such white spots greatly impairs the image quality. Since interlaced recording is intended to improve image quality, such a decrease in image quality cannot be overlooked. The above-described problem has occurred in a printer that does not involve main scanning of the head as well.
[0015]
The present invention has been made to solve the above-described problems in the prior art, and in the case of performing recording by an interlace method, an image is recorded by forming a raster while performing sub-scanning with low paper feed accuracy. An object of the present invention is to provide a technique for recording an image with sufficient image quality that does not impair the quality of the entire obtained image in the expanded region while expanding the region.
[0016]
[Means for solving the problems and their functions and effects]
In order to solve at least a part of the problems described above, the printing apparatus of the present invention employs the following configuration.
The first printing apparatus of the present invention includes:
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head provided with a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction;
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the second sub-scanning unit performs sub-scanning, each raster is formed while performing the sub-scanning with the sub-scanning amount smaller than the average sub-scanning amount by the first sub-scanning unit. The gist of the invention is that it comprises a raster forming means and a control means for controlling the second sub-scanning means.
[0017]
The first printing method of the present invention includes:
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing method capable of printing an image corresponding to input image data on the print medium by forming a plurality of rasters by
The head includes a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction,
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the sub-scan is moved so that the image is printed by performing the sub-scan with a sub-scan amount smaller than the average sub-scan amount performed with the first accuracy. And controlling the driving of the head.
[0018]
In such a printing apparatus and printing method, an entire area is formed from a region where an image is formed while performing sub-scanning with a first accuracy and a region where an image is formed while performing sub-scanning with a second accuracy lower than the first accuracy. The image is recorded in a wide recording area as compared with a printing apparatus and a printing method for forming an image of the image and forming the image while performing sub-scanning with the first accuracy.
[0019]
Moreover, in the printing apparatus and the printing method, the sub-scanning amount in the area expanded in this way is made smaller than the average sub-scanning amount performed with the first accuracy. In general, the smaller the amount of sub-scanning per time, the smaller the error in sub-scanning. Therefore, according to the printing apparatus and the printing method described above, sufficient image quality can be ensured even in a region where sub-scanning is performed with the second accuracy.
[0020]
In such a printing apparatus,
It is also desirable that the feed amount by the control means is one raster.
[0021]
Since the minute feed for each raster is the smallest sub-scanning amount, the error can be minimized.
[0022]
In the printing apparatus,
The control means selects some of the nozzles provided in the head to form a raster, and performs sub-scanning so that adjacent rasters are formed by different nozzles of the selected nozzles. It is desirable to be a means to do it.
[0023]
According to such a printing apparatus, the raster is formed only by some selected nozzles among the plurality of nozzles provided in the head. When the number of nozzles contributing to dot formation is small, the sub-scan feed amount is inevitably small, so that the error can be reduced even in the region where the sub-scan is performed with the second accuracy.
[0024]
In the above printing apparatus, sub-scanning is performed so that adjacent rasters are formed by different nozzles. By performing such sub-scanning, it is possible to disperse the dot shift based on the mechanical manufacturing error of the nozzle, and thus the obtained image quality can be further improved.
[0025]
In a printing apparatus that forms adjacent rasters with different nozzles,
The control means includes
It is desirable to be means for performing sub-scanning with a feed amount in which the fluctuation frequency of the interval between adjacent rasters is significantly greater than 1 cycle / mm.
[0026]
In the sub-scanning with the second accuracy, the interval between adjacent rasters varies based on the feed amount error, and unevenness of the image is formed. When such shading unevenness is visually recognized, so-called banding becomes conspicuous and image quality is impaired. In general, human visual intensity peaks at a spatial frequency near 1 cycle / mm, and decreases at a spatial frequency higher than that. According to the printing apparatus described above, the variation frequency of the interval between the adjacent rasters is significantly increased as compared with 1 cycle / mm, so that the unevenness in density based on the variation in the interval between the rasters is less likely to be visually recognized. it can. As a result, it is possible to improve the image quality in the region where the sub-scan with the second accuracy is performed.
[0027]
In a printing apparatus that forms adjacent rasters with different nozzles,
The control means includes
When the predetermined interval provided with a plurality of nozzles is k dots,
It can be a means for performing sub-scanning with a feed amount in which the number of adjacent rasters formed continuously is smaller than k.
[0028]
According to such a method, as will be described below, it is possible to suppress the gap between the rasters caused by the feed error and improve the image quality. Further, in such a method, it is possible to obtain an effect of making the shading unevenness inconspicuous by increasing the frequency at which the shading unevenness associated with the change in the raster interval occurs.
[0029]
Consider a case where a head in which nozzles are arranged at a predetermined interval k dots in the sub-scanning direction is used, and adjacent rasters are formed by different nozzles. There are k−1 unformed rasters between the rasters formed in the first raster formation. When k-1 rasters are sequentially formed by performing sub-scanning, generally, sub-scanning is performed so that adjacent rasters are continuously formed in the sub-scanning direction or the opposite direction. If such sub-scanning is performed, the number of adjacent rasters formed continuously is k. Conversely, a portion where adjacent rasters are not continuously formed appears every k. In such recording, a case where a constant feed error e occurs for each sub-scan is considered. In an area where adjacent rasters are continuously formed, the recording position shift between the rasters is equal to the feed error e. On the other hand, in a portion where adjacent rasters are not continuously formed, a feed error accumulated by k−1 sub-scans appears. The feed error between the rasters is (k−1) × e, which is a very large error. Such a large feed error is easily visible and causes a reduction in image quality. In addition, this large feed error appears at an interval equal to the nozzle interval, and often appears at a frequency where human visual intensity is high. For this reason, it is easy to be visually recognized, and tends to cause a decrease in image quality.
[0030]
According to the printing apparatus of the present invention, sub-scanning is performed so that the number of adjacent rasters formed continuously becomes smaller than the nozzle interval k. Therefore, the maximum value of the feed amount error generated between the rasters is smaller than (k−1) × e. Further, the interval at which the shift of the recording position between rasters varies can be made shorter than k. This means that it is possible to increase the spatial frequency of the shading unevenness caused by the shift of the storage position. Therefore, according to the printing apparatus of the above invention, it is possible to improve the image quality in the region where the sub-scan with the second accuracy is performed by these actions.
[0031]
As an example of realizing a feed amount in which the number of adjacent rasters continuously formed is smaller than the nozzle interval k,
The control means includes
When the number of main scans required to form each raster is s,
The number N of the selected nozzles is a value that is relatively prime to k within a range that does not become k · s ± 1,
It may be a means for performing sub-scanning with a constant feed amount of N / s.
[0032]
Of course, the feed amount in which the number of adjacent rasters formed successively is smaller than the nozzle interval k is not limited to the above relationship. For example, even when the number of nozzles is selected in the range of k · s ± 1, the number of adjacent rasters that are continuously formed by executing sub-scans with different feed amounts in combination is k. It is possible to make it smaller. The same applies even when the number N of nozzles is not a value that is relatively prime to k.
[0033]
The second printing apparatus of the present invention is
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head provided with a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction;
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the sub-scan is performed by the second sub-scanning unit, the number of main scans is larger than the number of main scans required to form each raster in the region where the sub-scan is performed by the first sub-scanning unit. The gist of the invention is that it comprises control means for controlling the dot forming means and the second sub-scanning means so as to form each raster.
[0034]
The second printing method of the present invention includes:
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing method capable of printing an image corresponding to input image data on the print medium by forming a plurality of rasters by
The head includes a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction,
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the raster is formed with the number of main scans larger than the number of main scans required to form each raster in the region where the sub-scan is performed with the first accuracy. Thus, the gist is to control the movement of the sub-scan and the driving of the head.
[0035]
According to such a printing apparatus and printing method, in an area where sub-scanning is performed with the second accuracy, an image is formed by increasing the number of main scans required to form each raster. For example, when each raster is formed by one main scan in an area where sub-scan is performed with the first accuracy, two or more main scans are performed in an area where sub-scan is performed with the second accuracy. Each raster will be formed. When each raster is formed by a plurality of main scans, the dots of each raster are intermittently formed in the main scan direction in each main scan. Various methods can be used to form intermittent dots. For example, when a raster is formed twice, odd-numbered dots are formed in the main scanning direction in the first main scanning, and the second main scanning is performed. A method of forming even-numbered dots by scanning is conceivable. Similarly, various dot forming methods can be considered when forming each raster by three or more main scans. The number of main scans required to form each raster is hereinafter referred to as the scan repetition number.
[0036]
If each raster is formed by a plurality of main scans in this way, errors during sub-scanning can be dispersed within each raster, so that the image quality when sub-scanning accuracy is low can be improved. it can. In the printing apparatus and the printing method, the number of scan repetitions is increased in the region where the sub-scan is performed with the second accuracy than the region where the sub-scan is performed with the first accuracy, so that the sub-scan with the second accuracy is performed. The degree of improvement in image quality in a region where scanning can be performed is relatively increased. In this way, it is possible to increase the uniformity of image quality while expanding the area for recording an image.
[0037]
The third printing apparatus of the present invention is
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head capable of forming two or more types of dots having different diameters by a plurality of nozzles provided in the sub-scanning direction for each color,
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the second sub-scanning unit performs sub-scanning, the raster forming unit is configured to form dots having a larger diameter at a higher rate than the region where the first sub-scanning unit performs sub-scanning. The gist is to provide a control means for controlling.
[0038]
The third printing method of the present invention includes:
Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. By forming a plurality of rasters, an image corresponding to the input image data can be printed on the print medium. Printing method Because
The head includes n (n is an integer of 2 or more) nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction.
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the sub-scan is performed so as to record an image while forming dots having a larger diameter at a higher rate than the region where the sub-scan is performed with the first accuracy. The gist is to control movement and driving of the head.
[0039]
According to such a printing apparatus and printing method, an image is formed by increasing the dot diameter in an area where sub-scanning is performed with the second accuracy. Even if the sub-scanning accuracy is lowered, so-called white spots do not occur while adjacent dots in the sub-scanning direction overlap each other, so that the image quality does not deteriorate so much. In the above printing apparatus and printing method, so-called white spots can be prevented by increasing the dot diameter so that adjacent dots overlap even when the sub-scanning accuracy is low. As a result, it is possible to improve the image quality in the region where the sub-scan is performed with the second accuracy.
[0040]
When using dots with a large diameter, this means using dots with a high density per unit area, so if you simply increase the diameter, the density is higher than the image that should originally be obtained. There is also a risk of forming an image. Therefore, in the printing apparatus and the printing method, it is preferable to appropriately set a ratio of using dots having a large diameter within a range in which the gradation of the image is not broken in consideration of such points.
[0041]
In the various printing apparatuses described above,
In the first region where sub-scanning is performed by the first sub-scanning means,
In a predetermined region that is not adjacent to the second region in which sub-scanning is performed by the second sub-scanning means, sub-scanning is performed with a predetermined feed amount that forms adjacent rasters with different nozzles,
In the intermediate area adjacent to the predetermined area and the second area, the raster forming means and the first sub-field are formed so as to form each raster by performing sub-scanning with a feed amount smaller than the predetermined feed amount. Second control means for controlling the scanning means may also be provided.
[0042]
According to such a printing apparatus, not only the image recording area can be expanded by the area where the sub-scanning is performed with the second accuracy, but also the area where the sub-scanning is performed with the first accuracy can be expanded. Even if the above-described various inventions are applied, it is natural that the image quality is higher in the region where the sub-scan is performed with the first accuracy. The image quality of the entire image can be improved.
[0043]
In this case,
The head is provided with p nozzles (p is an integer of 2 or more) at intervals of n rasters (n is an integer of 2 or more) in the sub-scanning direction.
In the intermediate region, the second control means
Sub-scanning is performed with a feed amount that completes an image in an area of m rasters (m is an integer smaller than p × (n−1)) smaller than the limit raster that can be sub-scanned by the first sub-scanning means. Thus, it is desirable that the second sub-scanning means is a means for controlling.
[0044]
In this way, when the head exists at a limit position where sub-scanning can be performed with the first accuracy, an image can be completed up to a part of the area. That is, an image can be formed up to such a region by sub-scanning with the first accuracy. The area in which the range of image recording is expanded while performing sub-scanning with the first accuracy is referred to as an intermediate area.
[0045]
The control means further includes
The feed amount controlled by the second control means is further
It is also desirable to use a feed amount in which adjacent rasters are formed by different nozzles.
[0046]
By applying such means, it is possible to disperse the dot shift caused by the mechanical manufacturing error of the nozzles in the intermediate region, so that the image quality can be further improved.
[0047]
Further, the feed amount controlled by the second control means may be one raster.
[0048]
If the sub-scan is executed with such a feed amount, the intermediate area can be expanded to the limit range where the sub-scan can be performed with the first accuracy.
[0049]
Since the printing apparatus of the present invention described above can also be configured by realizing the control of the head for recording dots by a computer, the present invention has an aspect as a recording medium on which such a program is recorded. It can also be taken.
[0050]
The first recording medium of the present invention is
A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In an area where sub-scanning is performed with the second accuracy,
A function of outputting a control signal for performing the sub-scanning with a sub-scanning amount smaller than an average sub-scanning amount performed with the first accuracy;
It is a recording medium on which a program capable of realizing by a computer a function of outputting control signals for forming an image in the order corresponding to the sub-scanning is recorded.
[0051]
The second recording medium of the present invention is
A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In the region where sub-scanning is performed with the second accuracy, each raster is scanned at a number of main scans greater than the number of main scans required to form each raster in the region where sub-scanning is performed with the first accuracy. It is a recording medium on which is recorded a program that can be realized by a computer with a function of outputting a control signal.
[0052]
The third recording medium of the present invention is
A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In the region where the sub-scan is performed with the second accuracy, a control signal is output so that dots having a larger diameter are formed at a higher rate than the region where the sub-scan is performed with the first accuracy. It is a recording medium on which a program capable of realizing functions by a computer is recorded.
[0053]
By executing the program recorded on the recording medium by the computer, the above-described printing apparatus of the present invention can be realized.
[0054]
Storage media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed materials printed with codes such as bar codes, and computer internal storage devices (memory such as RAM and ROM). ) And external storage devices can be used. Further, an aspect as a program supply apparatus that supplies a computer program for realizing a control function of the printing apparatus to a computer via a communication path is also included.
[0055]
All the inventions described above are naturally applicable to both a printing apparatus that forms each raster with main scanning in which the head reciprocates relative to the print medium and a printing apparatus that forms rasters without main scanning. Applicable.
[0056]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
(1) Device configuration
FIG. 1 is a block diagram showing the configuration of a printing apparatus as an embodiment of the present invention. As shown in the figure, a scanner 90 and a color printer 22 are connected to a computer 90, and a predetermined program is loaded and executed on the computer 90, thereby functioning as a printing apparatus as a whole. As shown in the figure, the computer 90 includes the following units connected to each other by a bus 80 with a CPU 81 that executes various arithmetic processes for controlling operations related to image processing according to a program. The ROM 82 stores programs and data necessary for executing various arithmetic processes by the CPU 81 in advance, and the RAM 83 temporarily reads and writes various programs and data necessary for the CPU 81 to execute various arithmetic processes. Memory. The input interface 84 controls input of signals from the scanner 12 and the keyboard 14, and the output interface 85 controls output of data to the printer 22. The CRTC 86 controls signal output to the CRT 21 capable of color display, and the disk controller (DDC) 87 controls data exchange with the hard disk 16, the flexible drive 15, or a CD-ROM drive (not shown). The hard disk 16 stores various programs loaded in the RAM 83 and executed, various programs provided in the form of device drivers, and the like. In addition, a serial input / output interface (SIO) 88 is connected to the bus 80. The SIO 88 is connected to the modem 18 and is connected to the public telephone line PNT via the modem 18. The computer 90 is connected to an external network via the SIO 88 and the modem 18, and a program necessary for image processing can be downloaded to the hard disk 16 by connecting to a specific server SV. It is also possible to load a necessary program from the flexible disk FD or CD-ROM and cause the computer 90 to execute it.
[0057]
FIG. 2 is a block diagram illustrating a software configuration of the printing apparatus. In the computer 90, an application program 95 operates under a predetermined operating system. A video driver 91 and a printer driver 96 are incorporated in the operating system, and the final color image data FNL is output from the application program 95 via these drivers. An application program 95 for performing image retouching reads an image from the scanner 12 and displays the image on the CRT display 21 via the video driver 91 while performing predetermined processing on the image. Data supplied from the scanner 12 is original color image data ORG that is read from a color original and includes three color components of red (R), green (G), and blue (B).
[0058]
When the application program 95 issues a print command, the printer driver 96 of the computer 90 receives image information from the application program 95, and signals that can be printed by the printer 22 (here, cyan, magenta, yellow, and black colors). Is converted into a binary signal). In the example shown in FIG. 2, the printer driver 96 includes a rasterizer 97 that converts color image data handled by the application program 95 into dot unit image data, and a printer 22 for the dot unit image data. The color correction module 98 that performs color correction according to the ink color to be used and the characteristics of color development, the color correction table CT that the color correction module 98 refers to, and the presence or absence of ink in dot units from the image information after color correction And a halftone module 99 for generating so-called halftone image information expressing the density in a certain area. The printer 22 receives the printable signal and records image information on a recording sheet.
[0059]
Next, a schematic configuration of the printer 22 will be described with reference to FIG. As shown in the figure, the printer 22 includes a mechanism for transporting the paper P by the paper feed motor 23, a mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 by the carriage motor 24, and a print head mounted on the carriage 31. And a control circuit 40 for exchanging signals with the paper feed motor 23, the carriage motor 24, the print head 28 and the operation panel 32. . Hereinafter, each mechanism and the like will be described in this order.
[0060]
First, a mechanism for conveying the paper P will be described. FIG. 4 is a side sectional view showing a mechanism for conveying the paper P of the printer 22 described above. The mechanism for transporting the paper P includes a paper feed roller 25a and a driven roller 25b provided on the paper feed side, and a paper discharge roller 27a and a serrated roller 27b provided on the paper discharge side. These rollers are driven by transmitting the rotation of the paper feed motor 23 described above with reference to FIG. 3 using a gear train (not shown). As shown in FIG. 4, first, the paper P is sandwiched between the paper feeding roller 25a and the driven roller 25b from the paper feeding side, and is conveyed by the rotation of both rollers. When the upper end of the paper P is sandwiched between the paper discharge roller 27a and the jagged roller 27b, these rollers are also sent to the paper discharge side. An image is recorded on the paper P by the head 28 in an area on the platen 26.
[0061]
The paper feeding accuracy is secured by the rollers 25a and 25b on the paper feeding side. Therefore, when the paper P is fed by the paper discharge roller 27a and the jagged roller 27b after the lower end of the paper P is separated from the paper feed roller 25a and the driven roller 25b, the accuracy of the feed amount is controlled by the paper feed side rollers 25a and 25b. Lower than when transported.
[0062]
Next, returning to FIG. 3, a mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 will be described. This mechanism includes a sliding shaft 34 that is installed in parallel with the axis of the platen 26 and that slidably holds the carriage 31, a pulley 38 that stretches an endless drive belt 36 between the carriage motor 24, and the carriage 31. The position detection sensor 39 etc. for detecting the origin position.
[0063]
The carriage 31 accommodates a cartridge 71 for black ink (Bk) and inks of six colors of cyan (C1), light cyan (C2), magenta (M1), light magenta (M2), and yellow (Y). The color ink cartridge 72 can be mounted. For two colors, cyan and magenta, two types of light and dark inks are provided. A total of six ink ejection heads 61 to 66 are formed on the print head 28 below the carriage 31. An inlet pipe 67 (which guides ink from the ink tank to the color heads) is provided at the bottom of the carriage 31. (See FIG. 5). When a black (Bk) ink cartridge 71 and a color ink cartridge 72 are mounted on the carriage 31 from above, an introduction tube 67 is inserted into a connection hole provided in each cartridge, and the ejection heads 61 to 66 are ejected from each ink cartridge. Ink can be supplied to the printer.
[0064]
A mechanism for ejecting ink and forming dots will be described. FIG. 5 is an explanatory diagram showing a schematic configuration inside the ink ejection head 28. When the ink cartridges 71 and 72 are mounted on the carriage 31, as shown in FIG. Negative pressure Ink in the ink cartridge is sucked out through the introduction pipe 67 and guided to the respective color heads 61 to 66 of the print head 28 provided at the lower part of the carriage 31. When the ink cartridge is first installed, an operation of sucking ink to the respective color heads 61 to 66 is performed by a dedicated pump. In this embodiment, a pump for sucking and a cap for covering the print head 28 at the time of sucking are performed. The illustration and description of such a configuration is omitted.
[0065]
As will be described later, the heads 61 to 66 of each color are provided with 48 nozzles Nz for each color (see FIG. 7). Each nozzle is one of electrostrictive elements and is responsive. An excellent piezo element PE is arranged. FIG. 6 shows the structure of the piezo element PE and the nozzle Nz in detail. As shown in the upper part of FIG. 6, the piezo element PE is installed at a position in contact with the ink passage 68 that guides ink to the nozzle Nz. As is well known, the piezo element PE is an element that transforms electro-mechanical energy at a very high speed because the crystal structure is distorted by application of voltage. In this embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE extends for the voltage application time as shown in the lower part of FIG. One side wall of 68 is deformed. As a result, the volume of the ink passage 68 contracts according to the expansion of the piezo element PE, and the ink corresponding to the contraction becomes particles Ip and is ejected from the tip of the nozzle Nz at high speed. Printing is performed by the ink particles Ip soaking into the paper P mounted on the platen 26.
[0066]
FIG. 7 is an explanatory diagram showing the arrangement of the inkjet nozzles Nz in the ink ejection heads 61-66. The arrangement of these nozzles consists of six sets of nozzle arrays that eject ink for each color, and 48 nozzles Nz are arranged in a staggered manner at a constant nozzle pitch k. The positions of the nozzle arrays in the sub-scanning direction coincide with each other. Note that the 48 nozzles Nz included in each nozzle array need not be arranged in a staggered manner, and may be arranged on a straight line. However, when arranged in a zigzag pattern as shown in FIG. 7, there is an advantage that the nozzle pitch k can be easily set small.
[0067]
FIG. 8 shows an enlarged view of the nozzle array and the state of dots formed by the nozzle array. As shown in FIG. 8, in this embodiment, dots can be recorded at a pitch of 1/6 of the nozzle pitch by sub-scanning the nozzle array. That is, in this embodiment, there is a relationship of nozzle pitch: recording pitch = 6: 1. Further, in order to prevent so-called white spots of dots, each dot is formed so as to partially overlap dots adjacent to each other in the main scanning direction and the sub-scanning direction.
[0068]
The printer 22 according to the present invention includes the nozzles Nz having a constant diameter as shown in FIG. 7, but three types of dots having different diameters can be formed using the nozzles Nz. This principle will be described. FIG. 9 is an explanatory diagram showing the relationship between the drive waveform of the nozzle Nz and the ejected ink Ip when the ink is ejected. The drive waveform indicated by the broken line in FIG. 9 is a waveform when a normal dot is ejected. Once a negative voltage is applied to the piezo element PE in the interval d2, the piezo element PE is deformed in the direction of increasing the cross-sectional area of the ink passage 68 as opposed to that described with reference to FIG. As shown in state A of 9, the ink interface Me called meniscus is indented inside the nozzle Nz. On the other hand, when a negative voltage is suddenly applied as shown in the section d2 using the drive waveform shown by the solid line in FIG. 9, the meniscus is greatly indented as compared with the state A as shown in the state a. Next, when the voltage applied to the piezo element PE is positive (section d3), ink is ejected based on the principle described above with reference to FIG. At this time, a large ink droplet is ejected from the state where the meniscus is not dented so much (state A), as shown in state B and state C, and from the state where the meniscus is greatly recessed (state a), state b and Small ink droplets are ejected as shown in state c.
[0069]
As described above, the dot diameter can be changed according to the rate of change when the drive voltage is made negative (sections d1 and d2). Further, it can be easily imagined that the dot diameter can be changed depending on the peak voltage of the drive waveform. In the present embodiment, based on such a relationship between the drive waveform and the dot diameter, a drive waveform for forming a small dot having a small dot diameter and a medium dot having the second dot diameter are formed. Two types of drive waveforms are prepared. FIG. 10 shows drive waveforms used in this embodiment. The drive waveform W1 is a waveform for forming a small dot, and the drive waveform W2 is a waveform for forming a medium dot. By using both appropriately, it is possible to form two types of dots having a small and medium dot diameter from a nozzle Nz having a constant nozzle diameter.
[0070]
Moreover, a large dot can be formed by forming a dot using both of the drive waveforms W1 and W2 of FIG. This state is shown in the lower part of FIG. The lower part of FIG. 10 shows a state from the time when the small and medium dot ink droplets IPs and IPm are ejected from the nozzle to the sheet P. When two types of small, medium, and small dots are formed using the drive waveform of FIG. 10, since the amount of change in the piezo element PE is larger in the medium dot, the ink droplet IP is ejected vigorously. Due to such a difference in the flying speed of ink, when the carriage 31 moves in the main scanning direction, small dots are ejected first, and then medium dots are ejected. If the timing is adjusted according to the distance between the carriage 31 and the paper P, both ink droplets can reach the paper P at the same timing. In this embodiment, the two types of drive waveforms shown in FIG. Large dot diameter Large dots are formed.
[0071]
Finally, the internal configuration of the control circuit 40 of the printer 22 will be described, and a method for driving the head 28 including the plurality of nozzles Nz shown in FIG. 7 will be described. FIG. 11 is an explanatory diagram showing the internal configuration of the control circuit 40. As shown in FIG. 11, the control circuit 40 includes a CPU 41, a PROM 42, a RAM 43, a PC interface 44 for exchanging data with the computer 90, a paper feed motor 23, a carriage motor 24, an operation panel 32, and the like. A peripheral input / output unit (PIO) 45 for exchanging signals with the timer, a timer 46 for measuring time, a transfer buffer 47 for outputting dot on / off signals to the heads 61 to 66, and the like. These elements and circuits are connected to each other via a bus 48. The control circuit 40 is also provided with a transmitter 51 that outputs a drive waveform (see FIG. 10) at a predetermined frequency, and a distributor 55 that distributes the output from the transmitter 51 to the heads 61 to 66 at a predetermined timing. ing. The control circuit 40 receives the dot data processed by the computer 90, temporarily stores it in the RAM 43, and outputs it to the transfer buffer 47 at a predetermined timing. Therefore, image processing for forming a multi-tone image is not performed on the printer 22 side. The control circuit 40 simply performs on / off in units of dots, that is, control of whether or not to form dots, and control of sub-scanning associated therewith.
[0072]
A mode in which the control circuit 40 outputs signals to the heads 61 to 66 will be described. FIG. 12 is an explanatory diagram showing connection of one nozzle row of the heads 61 to 66 as an example. One nozzle row of the heads 61 to 66 is interposed in a circuit having the transfer buffer 47 as the source side and the distribution output device 55 as the sink side, and each piezo element PE constituting the nozzle row has its electrode. One of these is connected to each output terminal of the transfer buffer 47, and the other is connected to the output terminal of the distribution output unit 55 all together. As shown in FIG. 12, a drive waveform of the transmitter 51 is output from the distribution output device 55. When the CPU 41 determines ON / OFF for each nozzle and outputs a signal to each terminal of the transfer buffer 47, only the piezo element PE that has received the ON signal from the transfer buffer 47 side is driven according to the drive waveform. The As a result, the ink particles Ip are simultaneously ejected from the nozzles of the piezo element PE that has received the ON signal from the transfer buffer 47.
[0073]
As shown in FIG. 7, since the heads 61 to 66 are arranged along the transport direction of the carriage 31, the timing at which each nozzle row reaches the same position with respect to the paper P is shifted. Accordingly, the CPU 41 outputs the dot ON / OFF signal via the transfer buffer 47 at a necessary timing after taking into account the positional deviation of the nozzles of the heads 61 to 66, and sets the dots of the respective colors. Forming. Further, as shown in FIG. 7, the output of on / off signals is controlled in consideration of the fact that each of the heads 61 to 66 has nozzles formed in two rows.
[0074]
In this embodiment, dots having different diameters can be formed by continuously outputting the drive waveforms W1 and W2 shown in FIG. 10 from a single transmitter 51. It is good also as what prepares each and forms the dot from which a diameter differs by the use properly.
[0075]
The printer 22 having the hardware configuration described above rotates the paper feed side rollers 25a and 25b and other rollers by the paper feed motor 23 to convey the paper P (hereinafter referred to as sub-scanning), while moving the carriage 31 to the carriage. The reciprocating motion is performed by the motor 24 (hereinafter referred to as main scanning), and simultaneously, the piezo elements PE of the color heads 61 to 66 of the print head 28 are driven to discharge the inks of the respective colors to form dots on the paper P. A color image is formed.
[0076]
In this embodiment, as described above, the printer 22 having the head for ejecting ink using the piezo element PE is used. However, a printer for ejecting ink by other methods may be used. For example, the present invention may be applied to a printer of a type in which electricity is supplied to a heater arranged in the ink passage and ink is ejected by bubbles generated in the ink passage.
[0077]
(2) Dot formation control
Next, image recording by the printer 22 in the present embodiment will be described. Hereinafter, how dots are formed by the main scanning of the head and the sub-scanning of the paper will be described in detail. FIG. 13 and FIG. 14 are flowcharts showing the control flow of main scanning and sub-scanning in this embodiment. This control is performed by the CPU 41 of the control circuit 40 of the printer 22 shown in FIG. 3 executing the above-described dot formation control routine.
[0078]
When the dot formation control routine is started, the CPU 41 inputs image data (step S100). This image data is data that has been subjected to color correction and other image processing by the printer driver 96 shown in FIG. 3, and each color dot is formed at any position in the main scanning direction and sub-scanning direction of the printing paper. This data specifies what should be done. In this embodiment, all data related to the image to be printed is input in step S100. Of course, the data may be sequentially input while forming dots to be described later.
[0079]
Next, the CPU 41 executes image recording by standard printing processing (step S200). The standard printing process in this embodiment is recording by a so-called interlace method. The flow of the standard printing process is shown in FIG. FIG. 15 shows how an image is recorded according to this embodiment. As shown in FIG. 15, in this embodiment, the image is largely formed of three regions according to the positional relationship between the paper feeding mechanism and the printing paper P shown in FIG.
[0080]
The first area is a standard printing area shown in FIG. This is an area where an image is recorded in a state where the paper P is sandwiched between the paper feed roller 25a and the driven roller 25b shown in FIG. 4, that is, in a state where the paper feed accuracy is sufficiently guaranteed. The second area is an intermediate processing area shown in FIG. This corresponds to a transitional area between a standard printing area and a third area described later. Even in this region, the paper feeding accuracy is sufficiently guaranteed. The third area is an extended printing area in FIG. This region is a region where the lower end of the paper P is removed from the paper feed roller 25a and the driven roller 25b shown in FIG. 4 and the paper is fed while being fed by the paper discharge roller 27a and the jagged roller 27b. Accordingly, in the extended printing area, an image is recorded with lower paper feed accuracy than in the standard printing or intermediate processing area. In principle, the printer 22 of the present embodiment can record an image on all areas of the paper P. However, in consideration of an error in the size of the paper P, an error in insertion into the printer 22, and the like, I try to leave some margins.
[0081]
The state of dots formed by the dot formation control (FIGS. 13 and 14) is shown in more detail in FIG. FIG. 17 shows a list of rasters formed by the nozzles at this time. For convenience of explanation, FIGS. 16 and 17 show an example in which the nozzle pitch is equivalent to 4 rasters and the number of nozzles is reduced to 7.
[0082]
FIG. 16 is a diagram showing the position of the nozzle in the sub-scanning direction during each main scanning. The vertical direction in FIG. 16 corresponds to the sub-scanning direction. In order to avoid the complexity of the figure, the nozzle positions are sequentially shifted to the right for each main scan. In FIG. 16, P1, P2,... Mean the first, second,. The encircled numbers indicate the positions of the nozzles in the sub-scanning direction in each main scanning. The numbers circled with bold lines mean that dots are formed at those positions, and the numbers circled with thin lines mean that nozzles are located but dots are not formed. doing. The value shown on the left side of FIG. 16 is a raster number RN given to each raster for convenience. As will be described later, the lowermost raster on which an image is recorded is guaranteed by the recording method while guaranteeing paper feed accuracy in the sub-scan. The number 0 (RN = 0) is used, and rasters below it are represented by positive numbers, and rasters above are represented by negative numbers. The number represented in the form of “L =” represents the paper feed amount in each sub-scan by the number of rasters.
[0083]
When the standard printing process routine (FIG. 14) is started, the CPU 41 sets the dot formation data (step S110) and then forms dots while performing main scanning (step S120). In the example of FIG. 16, since the nozzle pitch is 4 rasters, the dot formation data is obtained by sequentially extracting data in the main scanning direction every 4 rasters from the head of the previously input image data. These data are sent to the transfer buffer 47 shown in FIG. In dot formation, as shown in FIG. 12, the head 28 is driven to eject ink by outputting a drive waveform as shown in synchronization with the position of the head 28 in the main scanning direction. In this way, in the main scan P1 in FIG. 16, dots are formed every four rasters in the region above the raster number -28 (region where RN≤-28).
[0084]
FIG. 17 shows the correspondence between nozzle positions and raster numbers in each main scan. .. In the left column of FIG. 17 corresponds to each nozzle number in FIG. 16, and P1, P2... Shown in the upper column are also main scans in FIG. Corresponding to P1, P2,. The numbers in the table indicate the raster number RN that each nozzle forms in each main scan. From FIG. 17, it can be seen that the first nozzle forms a raster with raster number -52 in the main scan P1. Incidentally, this is a region above the region shown in FIG.
[0085]
Next, the CPU 41 controls the paper feed motor 23 to perform sub-scanning (step S130). The paper feeding method is as already described with reference to FIG. In the example of FIG. 16, paper feeding corresponding to 7 rasters is executed, and the position of the head 28 moves to P2 in FIG. This feed amount is set to a feed amount at which the nozzle can be used most effectively among various feed amounts that can record an image without causing raster omission by the interlace method. The feed amount can be determined according to the nozzle pitch, the number of nozzles, and the number of scan repetitions, but the setting method is well known and will not be described.
[0086]
After the sub-scanning, the above-described processes (steps S110 to S130) are repeatedly executed to form dots at the position indicated by the main scanning P2 in FIG. 16, that is, the area above the raster number -20. By repeating this process, it is possible to record an image while intermittently forming a raster. For example, as is apparent from FIG. 16, when the main scan P4 is executed, it can be seen that the image is completed in the raster numbers −34 to −25. Thereafter, this process is repeatedly executed until image formation is completed (step S140) to form an image. However, in this embodiment, as will be described later, printing in another printing mode is executed after the standard printing process (step S200 in FIG. 13). This means not the end of printing of the entire data but the end of image formation by the standard print processing routine.
[0087]
Note that whether or not the image formation by the standard printing process is completed is determined according to the number of rasters to be formed by an intermediate process (step S300 in FIG. 13) and an enlarged area printing process (step S700) described later. The If the size or the like of the printing paper P is specified in advance, the number of rasters constituting the input image data is known, and the number of rasters required for the enlarged area printing process and the intermediate process is also known. Based on these pieces of information, it is possible to determine how many rasters should be standard printed from the upper end of the image data. By comparing the raster thus obtained and the actually formed raster, it can be easily determined whether or not the standard printing process should be terminated. However, in the present embodiment, the area to be standard printed is set with a slight margin in the range determined in this way. This is because the size of the paper is not strictly constant, and an error may occur in the printing area due to slipping or other factors such as when the paper is sucked.
[0088]
For the case where the paper size is unknown, a sensor for detecting the paper edge is provided at a predetermined position further upstream than the paper feed roller 25a and the driven roller 25b in FIG. Based on this, the end of the standard printing process may be determined. For example, if a paper edge is detected by a known sensor that optically detects the edge of the paper, the distance from the area where printing is performed to the lower edge of the paper is known when the paper edge is detected. Since the number of rasters of the image to be recorded is known, the same determination as described above may be made based on these pieces of information.
[0089]
Thus, after the image formation by the standard printing process is completed, the CPU 41 executes the printing of the image by the intermediate process (step S300 in FIG. 13). Since the dot formation flow itself in the intermediate process is the same as the standard printing process routine shown in FIG. 14, the flowchart is omitted. In the intermediate processing, the paper feed amount in the sub-scan is different from the paper feed amount in the standard printing.
[0090]
In the intermediate process (step S300), unlike the paper feed amount equivalent to 7 rasters in the standard process, first, paper feed equivalent to 4 rasters is executed to form a raster (main scan P5 in FIG. 16). The meaning of these four rasters will be described later. Next, a raster is formed while feeding three raster sheets (main scans P6 to P8 in FIG. 16). At this time, for example, the first nozzle in the main scan P7 may have overlapping nozzles at the raster positions that have already been formed. Therefore, such nozzles mask the dot formation data and perform dot formation. You will be kept from breaking. In FIG. 17, a nozzle indicated as n / a means a nozzle on which data is masked. Note that the position of the main scan P8 in FIG. 16 is a limit position where the paper can be fed while guaranteeing accuracy. That is, at this time, the lower end of the paper P is in a state immediately before it is detached from the paper feed roller 25a and the driven roller 25b. Strictly speaking, in the present embodiment, the position of the main scan P8 is a position that allows for a margin of about 2 mm from the limit position.
[0091]
The setting of the feed amount in the intermediate process will be described. In the intermediate processing of this embodiment, paper feed is performed with a constant feed amount of 3 rasters following a transient feed amount of 4 rasters. This constant feed amount corresponds to an interlace feed amount when three nozzles having a nozzle pitch of four rasters are provided. That is, in the intermediate processing of this embodiment, the feed amount is set so that the interlaced recording is performed using three of the seven nozzles in total. Actually, in the main scan P8 of FIG. 16, only three nozzles from the third nozzle to the fifth nozzle form dots. In the main scans P6 and P7, three or more nozzles are used in order to prevent the raster from being lost due to the connection with the standard printed region. In addition, the transitional feed for four rasters executed at the beginning of the intermediate process is also set so as not to cause a missing raster. The transient feed amount is determined based on both a parameter such as a feed amount in standard processing and a parameter such as a feed amount in intermediate processing.
[0092]
In this way, the interlaced recording in which the number of used nozzles is apparently reduced in the intermediate processing is executed by using such a recording method, thereby extending the area where the image can be recorded with the paper feeding accuracy guaranteed. Because it can. This point will be described by comparison with FIG.
[0093]
As already described, FIG. 44 shows a state in which an image is recorded only by the interlace method with a paper feed amount equivalent to 7 rasters. In FIG. 16 and FIG. 44, the positions of the raster numbers in the sub-scanning direction are unified (for example, the position of the 7th nozzle in the main scanning P4 is the raster number -7). The nozzle pitch and the number of nozzles are also the same. As already described, in FIG. 44, the area up to the main scan P6 is the area where the paper feed accuracy is guaranteed. At this time, since a raster omission occurs at the raster number -10, the image is completed only in the area above the raster number 11 (area RN ≦ -11). On the other hand, in FIG. 16, an image is formed in an area up to raster number 0 (area where RN ≦ 0) by adopting intermediate processing.
[0094]
If the intermediate processing with the reduced number of used nozzles is executed in this way, the area in which an image can be recorded is expanded while guaranteeing paper feed accuracy. On the other hand, if the number of used nozzles is reduced, the dot formation efficiency is lowered and the printing speed is lowered. Further, if the number of used nozzles is reduced, a situation occurs in which adjacent rasters must be formed by the same nozzle. In this embodiment, such circumstances are comprehensively determined, and the intermediate process including the above-described feed amounts is set. However, this feed amount can be set to various values according to these circumstances. However, whatever value is set, the feed amount must be smaller than the feed amount in the standard process. This is because when a feed amount larger than the feed amount in the standard process is performed, an area where an image can be recorded cannot be enlarged while ensuring the paper feed accuracy.
[0095]
After executing the recording by the intermediate processing in this way, the CPU 41 executes alignment feeding (step S400). The alignment feed refers to performing sub-scanning at the position of main scanning P9 in FIG. The setting of the feed amount is determined in accordance with the feed amount of the extended print process performed thereafter. Before describing the extended printing process in the present embodiment, the concept of alignment feeding will be described with reference to FIGS. 18 and 19.
[0096]
FIG. 18 is an explanatory diagram showing one aspect of extended printing. FIG. 19 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and rasters at that time. The dot formation in the standard printing and intermediate processing of FIG. 18 is the same as that described above with reference to FIG. In FIG. 18, the dot formation in the extended printing is different from the dot formation in this embodiment (FIG. 16).
[0097]
As described above, in the present embodiment, as a result of the intermediate processing, the image is completed in the region above the raster number 0 (region where RN ≦ 0). An image is formed in an area below the number 1 (area where RN ≧ 1). However, as is apparent from FIG. 18, the 6th nozzle and the 7th nozzle already exist in this region when the intermediate processing is completed. Since the sub-scan can be performed only in one direction, the No. 6 nozzle and the No. 7 nozzle cannot be used in the extended printing process. Accordingly, in the extended printing process, recording by the interlace method is performed using five nozzles from the first nozzle to the fifth nozzle. Hereinafter, the fifth nozzle is referred to as an end nozzle in this sense. If the extended printing process is executed using up to the 4th nozzle, the end nozzle is the 4th nozzle.
[0098]
In the state where the intermediate processing is completed (main scan P8 in FIG. 18), the end nozzle No. 5 is located above the area where the image is completed (raster number -2 in FIG. 18). In order to form an image adjacent below raster number 1, it is necessary to perform interlaced recording from the state in which nozzle 5 matches raster number 0.
[0099]
In order to execute the extended printing process, it is necessary to perform sub-scanning with a feed amount set for performing interlaced recording. If the feed amount in the extended printing process is set by the same method as that for setting the feed amount by the interlace method in the standard printing process, it corresponds to 5 rasters. The reason why it is smaller than the feed amount in the standard printing process is that the number of nozzles that can be used in the extended printing is reduced.
[0100]
As described above, when the nozzles usable from the first nozzle to the fifth nozzle can be used when recording by the interlace method in the extended printing process, the alignment feed in step S400 matches the end nozzle to the raster number 0. 7 rasters can be obtained from the sum of 2 rasters, which are the feed amount required for printing, and 5 rasters, which is the feed amount in the extended printing process. In FIG. 18, after aligning by 7 raster feeds obtained in this way, dot recording by the interlace method is executed with a constant feed amount of 5 rasters.
[0101]
On the other hand, in FIG. 16, five raster feeds are executed as alignment feed (see feed amounts from main scans P8 to P9 in FIG. 16). Further, in the extended printing area, dots are recorded while performing sub-scanning by sending three rasters. As already described, in extended printing, only nozzles 1 to 5 can be used. FIG. 18 shows the dot recording when all of these nozzles are used, but in this embodiment (FIG. 16), among these nozzles, the first and second nozzles are not used. Dots are recorded using only the 3rd to 5th nozzles. When set in this way, the feed amount for recording by the interlace method is further reduced to 3 rasters. Accordingly, in addition to the feed amount of 2 rasters required to move the nozzle No. 5 as the end nozzle to the raster number 0 (RN = 0), the feed amount of alignment is obtained as 5 rasters. The reason why the number of nozzles used in extended printing in this embodiment is reduced to three will be described later.
[0102]
After performing the alignment feed in this way, the CPU 41 sets the nozzles to be used (step S500), and performs data mask processing for the nozzles that are not used (step S600). In the present embodiment, as described above, nozzles 3 to 5 are set as use nozzles. The data mask process is a process for preventing dot formation by preventing the dot formation data from being transferred to the transfer buffer 47 (see FIGS. 11 and 12). Accordingly, as shown in FIG. 17, the nozzles No. 1, No. 2, No. 6, and No. 7 are all set to “n / a” in the extended printing.
[0103]
Next, the CPU 41 executes an extended printing process (step S700). Since the flow of dot formation in the extended printing process is the same as the standard printing process routine shown in FIG. 14, the flowchart is not shown. In the intermediate processing, the paper feed amount in the sub-scan is different from the paper feed amount in the standard printing. As described above, in the extended printing process, dots are formed by an interlace method using a feed amount for three rasters. Accordingly, in the extended printing process, dots are formed at the positions of the main scans P10 to P14 in FIG. At this time, since an image has already been formed in the region above the raster number 0 (region where RN ≦ 0), the nozzles existing in the region do not form dots. For example, the first nozzle forms a raster for the first time after the main scan P12.
[0104]
FIG. 16 shows how dots are formed when the nozzle pitch and the number of nozzles are reduced. On the other hand, the printer 22 of this embodiment includes 48 nozzles at a nozzle pitch corresponding to 6 rasters. The state of dot formation in such a case is shown in FIGS. 20 and 21 in the same format as FIG. FIG. 20 shows the correspondence between the nozzles No. 1 to No. 24 and the raster, and FIG. 21 shows the correspondence between the nozzles No. 25 and after. As shown in these figures, 47 raster paper feeds are performed as standard processing (step S200 in FIG. 13), and 15 raster transition paper feeds and 5 raster paper feeds are performed as intermediate processing (step S300). Forty-seven raster paper feeds are performed as alignment feed (step S400), and then 43 raster paper feeds are performed as extended print processing (step 700).
[0105]
According to the printing apparatus described above, high-quality images can be obtained by the interlace method in the area where standard printing is performed. In addition, by adopting the intermediate processing, it is possible to expand an area where an image can be formed while guaranteeing accuracy of paper feeding. Since an image is recorded by the interlace method even in such an extended area, a high-quality image can be obtained. The area in which an image can be recorded can be expanded downward by executing extended printing.
[0106]
Further, by reducing the number of nozzles used in extended printing to three, the sub-scan feed amount in extended printing can be reduced. That is, if five nozzles are used in extended printing, sub-scanning is performed with a feed amount of 5 rasters as shown in FIG. 18, but in this embodiment, three nozzles are used. Therefore, as shown in FIG. 16, extended printing can be executed by sub-scanning consisting of a feed amount of 3 rasters. As described with reference to FIG. 4, the sub-scan paper feed accuracy is not sufficiently ensured in the area for extended printing. In general, a paper feed error in sub-scanning occurs due to slippage between the paper P and a roller that feeds the paper. Therefore, if the paper feed amount is reduced once, the slippage, that is, the error can be reduced. In this embodiment, while sacrificing a slight decrease in printing speed, the number of nozzles used in extended printing is deliberately reduced to reduce the paper feed amount and reduce the sub-scanning error. As a result, according to the printer 22 of the present embodiment, a relatively good image can be obtained even in the extended print area.
[0107]
In addition to the above-described effects, the printer 22 of the present embodiment can improve the image quality in the extended printing area by making it difficult to visually recognize the unevenness of light and shade caused by the variation in the interval between the rasters based on the feed error. Can be planned. This effect will be described.
[0108]
In the above-described embodiment, interlaced recording using fewer nozzles is performed as extended printing than when standard printing is performed. When recording by the interlace method, the nozzle pitch k (dot) and the number N of nozzles are generally selected so as to have a prime relationship. At this time, if sub-scanning is performed with a constant feed amount N (dots) corresponding to the number N of nozzles, interlaced recording can be realized. The selection of the number of nozzles and the selection of the feed amount in the above embodiment is an example made in consideration of such a relationship.
[0109]
When the number of nozzles and the feed amount are set in this way, a number of rasters corresponding to the number of used nozzles are continuously formed in the sub-scanning direction or the opposite direction. An example of the extended print area in FIG. 18 will be described. As described above, in FIG. 18, in the extended printing area, interlaced recording using five nozzles arranged at a 4-dot pitch is executed. As for the five rasters having the raster numbers 5 to 9, adjacent rasters are formed in order in five consecutive main scans from the main scans P9 to P13. When the feed amount is set so as to satisfy the above relationship in the interlace, the number of rasters corresponding to the number of used nozzles is continuously formed in this way. In FIG. 18, the raster is continuously formed in the sub-scanning direction, but the raster may be continuously formed in the direction opposite to the sub-scanning direction. Four rasters with raster numbers 1 to 4 are also formed continuously. The reason why the number of continuously formed rasters is less than the number of used nozzles is based on the area immediately after the start of extended printing.
[0110]
In the extended print area, the feed accuracy in the sub-scanning direction is lower than in the standard print area. FIG. 22 shows how a raster is formed when a constant feed error e occurs for each sub-scan in the extended print area of FIG. FIG. 22 shows only the dots formed in the extended region of FIG. 18 in an enlarged manner. The meaning of the symbols is the same as in FIG. The left side of FIG. 22 shows the dot positions when there is no error in sub-scanning. The right side of FIG. 22 shows the dot positions when a constant feed error e occurs. FIG. 22 shows a case where an error e occurs in the direction in which the feed amount increases.
[0111]
The position of the No. 4 nozzle in the main scan P9 in FIG. 22 is compared. Compared to the case where there is no feeding error, dots are recorded at a location shifted by e in the sub-scanning direction. In the main scanning P10, a feeding error further occurs by e with respect to the main scanning P9. Therefore, the cumulative feed error in the main scan P10 is 2e. In the main scan P10, the dot is only 2e in the sub-scan direction compared to the case where there is no feed error. Shifted Recorded in place. Similarly, in the main scans P11, P12, and P13, the cumulative feed errors are 3e, 4e, and 5e, respectively. The cumulative feed error in each main scan is shown in the lower part of FIG.
[0112]
An error in the interval between adjacent rasters when dots are recorded including the above-described feed error is shown on the right side of FIG. As for the error of the interval, the difference between the accumulated errors of the main scanning forming each raster may be obtained. For example, the interval between rasters formed by the main scan P10 (cumulative error 2e) and the main scan P9 (cumulative error e) is obtained as e based on the difference between the accumulated feed errors of the two. Thereafter, the error of the interval between the rasters can be obtained in the same manner. This error is a constant value e between adjacent rasters as shown in FIG. An error of −3e occurs between adjacent rasters that are not formed. The rasters that are not formed adjacent to each other appear for each number corresponding to the number of used nozzles. In the recording shown in FIG. 18, a portion where the interval between rasters is greatly deviated from the original value occurs every five rasters. When such a portion is visually recognized, so-called banding occurs, and the image quality may be impaired.
[0113]
Whether or not the deviation of the raster interval is easily visible can be measured by the spatial frequency due to the uneven density. FIG. 23 shows the relationship between spatial frequency and visual intensity. As shown in FIG. 23, it can be seen that the human visual intensity reaches a peak at a spatial frequency near 1 cycle / mm. In other words, the light and shade produced at such a spatial frequency is sensitive to human vision as unevenness. As described with reference to FIG. 22, when a variation in density occurs at intervals corresponding to the number of used nozzles, the variation in density tends to become a spatial frequency around 1 cycle / mm as the number of used nozzles increases. Therefore, the shading variation accompanying the decrease in the feeding accuracy is likely to be visually recognized as banding.
[0114]
With regard to the above-described embodiment (FIG. 16), the variation in shading accompanying a decrease in feeding accuracy will be examined. Three rasters are continuously formed in the extended printing area. For example, raster numbers 1 to 3 shown in FIG. 16 are continuously formed. In the example of FIG. 16, regions where adjacent rasters are not continuously formed appear every three. The interval at which the fluctuation occurs is also shorter than the example shown in FIG. 22, and the spatial frequency is increased. Further, the deviation generated in that portion is smaller than the absolute value 3e of the deviation described in FIG. 22, and is only 2e in absolute value. Therefore, in the dot recording in the above-described embodiment, the variation in shading due to the decrease in sub-scan feed accuracy is not easily recognized as banding, and the image quality can be improved.
[0115]
A recording method suitable for improving the image quality by increasing the frequency of the fluctuation in shading in the sub-scanning direction in the extended printing area will be described as a second mode of the above embodiment. A state of dots recorded according to the second mode is shown in FIG. FIG. 25 shows the correspondence between the nozzle position and the raster number in each main scan. FIG. 24 shows an example using seven nozzles arranged at a nozzle pitch of 8 dots. Further, for convenience of illustration, each nozzle from No. 1 nozzle to No. 7 nozzle is indicated by a symbol. The correspondence between the symbol nozzle numbers is shown in the lower right of FIG.
[0116]
In the standard printing area, printing is performed by executing sub-scanning with a fixed feed amount of 7 dots. Thereafter, sub-scanning is performed with a 4-dot transitional feed amount, and printing is performed with fine feed for each dot as intermediate processing. Various other settings are possible for the feed amount of the intermediate process.
[0117]
Subsequently, after 21 dots are fed transiently, extended printing is performed with fewer nozzles than those used in standard printing. The method for setting the transient feed amount is the same as in the first embodiment (FIG. 16). In the second mode, extended printing is performed using five nozzles. The method for setting the number of nozzles used in extended printing is as follows.
[0118]
As described above, when performing interlaced recording, the nozzle pitch and the number of nozzles are generally selected so as to be relatively prime. Accordingly, in the second mode, a value that is prime to the nozzle pitch 8 is selected. In the second mode, in addition to this condition, the number of nozzles is set avoiding the value “k · s ± 1”. k is the nozzle pitch, and s is the number of scan repetitions, that is, the number of main scans required to form each raster. In the second mode, since “nozzle pitch k = 8” and “scan repetition number s = 1”, the used nozzle is selected with a value other than “9 and 7”. As the number of used nozzles satisfying the above two conditions, the number of nozzles is set to 5 in the second mode.
[0119]
When the number of nozzles and the nozzle pitch are selected to be relatively prime, interlaced printing can be performed by performing sub-scanning with a feed amount corresponding to the number of nozzles. Therefore, in the second mode, extended printing is performed with a constant feed amount equivalent to 5 dots. At this time, as is apparent from FIG. 24, each raster in the extended printing area does not have a portion where adjacent rasters are formed by continuous main scanning. This is because the number of nozzles is set avoiding the value “k · s ± 1”.
[0120]
FIG. 26 shows the manner in which the interval between rasters fluctuates when recording is performed according to the second mode, in the same format as in FIG. The correspondence between symbols and nozzle numbers is shown in the lower left of FIG. FIG. 26 shows only the dot recording position when the sub-scan feed includes an error. In the main scans P16 to P24, the accumulated feed errors are values e to 9e, respectively. The variation of the spacing between each raster is shown on the right side. As shown in the figure, the interval between rasters fluctuates with a period of “−3e, 5e, −3e”. The maximum variation is 5e, and the portion where the maximum variation occurs appears every three rasters in the sub-scanning direction. As a comparison, consider a case where seven adjacent rasters corresponding to the nozzle pitch are continuously formed. In this case, as described above with reference to FIG. 22, the maximum fluctuation value is 7e, and the portion where the largest fluctuation occurs appears every 7 rasters. The maximum value of fluctuation in recording in the second mode is smaller than the maximum value of fluctuation when seven rasters are continuously formed. In addition, the interval at which the maximum value of fluctuation appears is less than half, and the spatial frequency of the light and shade accompanying the feed amount error becomes a high value.
[0121]
As described above, if the recording according to the second mode is executed in the extended printing, in addition to the effect of improving the image quality by reducing the number of used nozzles, the banding is made inconspicuous by increasing the spatial frequency due to the change in the interval between rasters An effect can be obtained. If the number of nozzles to be used in the extended printing area is set in consideration of the relationship described above, the same recording as in the second mode, that is, adjacent rasters are continuous even with nozzle pitches and nozzle numbers other than those shown in FIG. Thus, it is possible to realize printing with very few portions. In FIG. 24, there is no portion in which the adjacent rasters are continuously formed in the extended print area, but the same effect can be obtained even if a portion in which the adjacent rasters are continuously formed is generated. Can be obtained.
[0122]
Recording that shortens the fluctuation cycle of the interval between rasters in the extended printing region can be realized even when the number of used nozzles is selected as a value that is not a prime value for the nozzle pitch. The recording in this case will be described as a third aspect. FIG. 27 is an explanatory diagram showing how dots are recorded according to the third mode. FIG. 28 shows the correspondence between nozzle positions and raster numbers in each main scan. FIG. 27 shows an example using seven nozzles arranged at a nozzle pitch of 4 dots.
[0123]
In the third mode, as in the first embodiment (see FIG. 16), standard printing is executed with sub-scans of 7 dots each, followed by a transient feed of 4 dots, and intermediate with sub-scans of 3 dots. Execute the process. Next, in the third mode, the 11-dot transitional feeding is performed and the extended printing is executed. The method for setting the transient feed amount is the same as in the first embodiment. In the third aspect, the number of nozzles used in the extended printing is selected to be the same four as the nozzle pitch in a range smaller than the number of nozzles used in standard printing.
[0124]
In such a case, even if sub-scanning is performed with a constant feed amount, interlaced recording cannot be realized. Therefore, in the third mode, the sub-scan is realized while changing the feed amount periodically, with the feed amount of “6 dots, 3 dots, 2 dots, 5 dots” as a set. However, the average feed amount is 4 dots, which matches the number of nozzles used. Such feed amount is set so that the rasters recorded by the nozzles do not overlap under the condition that the average feed amount matches the number of used nozzles. It can be set even in cases other than the number of nozzles and the nozzle pitch shown in FIG.
[0125]
When extended printing is executed while changing the feed amount in this way, the number of adjacent rasters formed continuously as shown in FIG. 27 becomes very small. Only two rasters are formed continuously. Therefore, if the extended printing according to the third aspect is executed, in addition to the effect of improving the image quality by reducing the number of used nozzles, the effect of making the banding inconspicuous by increasing the spatial frequency due to the variation in the interval between rasters is obtained. be able to.
[0126]
In the above-described embodiments, all images are formed with a constant dot diameter. On the other hand, when extended printing is performed, dots having a diameter larger than that used in standard printing and intermediate processing may be formed. For convenience of explanation, the former is called “small dot” and the latter is called “large dot”. The formation of large dots is as described above with reference to FIGS.
[0127]
FIG. 29 shows a state where large dots are formed. In order to avoid the complexity of the figure, the state of dots is shown by alternately using solid lines and broken lines for each raster. As described above with reference to FIG. 46, when the sub-scanning accuracy decreases, the recording pitch in the sub-scanning direction varies, and in some cases, a so-called white spot (region a3 in FIG. 46) occurs. FIG. 29 shows a state in which large dots are recorded at the same recording pitch in the sub-scanning direction as in FIG. As is clear from the comparison between FIG. 29 and FIG. 46, by increasing the dot diameter, adjacent dots overlap even if the sub-scanning accuracy is reduced, so that white spots can be prevented. Since human vision is very sensitive to white spots, image quality can be significantly improved if white spots can be prevented.
[0128]
However, when using large dots, it means that dots with a high density per unit area are used. Therefore, if the diameter is simply increased, an image with a higher density than the image that should originally be obtained. May also form. Considering this point, it is preferable to appropriately set the ratio of using small dots and large dots within a range that does not destroy the gradation of the image.
[0129]
FIG. 30 shows a state in which dots having different diameters are mixed and recorded so as not to destroy the gradation of the image. FIG. 30 also shows a state in which large dots are recorded at the same recording pitch in the sub-scanning direction as in FIGS. 29 and 46. As shown in FIG. 30, white spots can be prevented by mixing large dots appropriately. Both dots may be formed using random numbers, or may be formed according to a predetermined pattern such as a checkered pattern.
[0130]
FIG. 31 and FIG. 32 show examples of dot recording rates when dots having different diameters are recorded together. FIG. 31 shows the dot recording rate in the case where an image is recorded using only small dots, that is, in the standard processing described above. Each gradation can be expressed by increasing the recording rate of small dots as the gradation value increases. The dot recording rate refers to the ratio of dots formed to express a gradation value for a solid region having a certain gradation value.
[0131]
FIG. 32 shows the recording rate of each dot when large dots and small dots are mixed in the extended printing. Each gradation value can be expressed by decreasing the proportion of small dots as the gradation value increases and large dots are used. The proper use of both dots can be variously set according to the dot diameter of both. It is also possible to use a large dot from a lower gradation value than shown in FIG. In this embodiment, the recording rate is experimentally set so that gradation can be appropriately expressed while making sub-scan feed accuracy inconspicuous in extended printing. Naturally, large dots and small dots can also be mixed and recorded in the standard printing process. In such a case, it is desirable to prepare at least two types of recording rate settings (for standard printing and for extended printing) so that the recording rate of large dots can be increased in extended printing.
[0132]
As shown in FIG. 7, the printer 22 of this embodiment includes two types of light and dark inks for cyan and magenta. Therefore, when using dots with a large diameter, light ink may be used according to the gradation value of the image to be expressed. Regarding the proper use of these dots, a recording rate similar to that shown in FIG. 32 can be set in advance.
[0133]
The method of improving the image quality by forming dots having a large diameter in extended printing is an effective means even when applied alone, as well as when applied to the above-described embodiment. Of course, the present invention can also be applied to extended printing with a paper feed amount as shown in FIG.
[0134]
(3) Dot formation control in the second embodiment
Next, dot formation according to the second embodiment will be described. The printer 22 in the second embodiment has the same hardware configuration as that of the first embodiment shown in FIGS. Also, the flow of processing when forming dots is the same as in the first embodiment (FIGS. 13 and 14).
[0135]
FIG. 33 is an explanatory diagram showing how dots are formed in the second embodiment. FIG. 34 is an explanatory diagram showing the correspondence of rasters formed by each nozzle in each main scan. As shown in these drawings, also in the second embodiment, in the standard printing process, a raster is formed while feeding paper for 7 rasters. Also in the intermediate processing, as in the first embodiment, after performing a transient feed for four rasters, an image is recorded while feeding three rasters at a time.
[0136]
In the second embodiment, the paper feed amount in extended printing is different from that in the first embodiment. As shown in FIGS. 33 and 34, in the second embodiment, an image is recorded while performing fine feed for each raster in extended printing (after main scanning P9 in FIG. 33). At this time, since it is not necessary to form dots on a raster on which an image has already been recorded, dots are formed using only No. 5 nozzle. The reason why the No. 5 nozzle is used is that the No. 5 nozzle is an end nozzle at the end of the intermediate processing, and the paper feed amount at the time of shifting to the extended printing is minimized.
[0137]
The sub-scan feed (start feed amount from the main scan P8 to P9 in FIG. 33) at the start of extended printing is set based on the same concept as the alignment feed described in the first embodiment. That is, the feed amount of the alignment feed is 3 from the sum of 2 rasters corresponding to the feed amount for moving the No. 5 nozzle as the end nozzle to the position of raster number 0 and 1 raster as the feed amount in the extended printing. It becomes a raster.
[0138]
According to the printer of the second embodiment, sub-scanning can be performed with the highest accuracy by employing minute feed in extended printing. As a result, the image quality in extended printing can be improved.
[0139]
In the second embodiment, each raster may be formed by two main scans during extended printing. FIG. 35 shows how dots are recorded in such a case. FIG. 36 shows the correspondence between the nozzle number, main scanning, and raster number in that case.
[0140]
The dot recording method shown in FIG. 35 is the same as that in the second embodiment (FIG. 33) described above in standard printing and intermediate printing (main scans P1 to P8). Further, the sub-scanning in the extended printing is the same as that in the second embodiment.
[0141]
However, in the dot recording method shown in FIG. 35, each raster is formed by two main scans in the extended printing using two nozzles, the fifth nozzle and the fourth nozzle. For example, for raster number 1, some dots are formed by the fifth nozzle in the main scan P9, and the remaining dots are formed by the fourth nozzle in the main scan P13. Such a method of forming each raster by two or more main scans is called an overlap method.
[0142]
FIG. 37 shows the state of extended printing dots by the recording method of FIG. In FIG. 37, dots indicated by circles are dots formed by the fifth nozzle, and dots indicated by diamonds are dots formed by the fourth nozzle. In FIG. 37, in order to avoid the complexity of the figure, dots are represented by alternately using actual battles and broken lines for each raster. In the present embodiment, as shown in FIG. 37, in the 5th nozzle, in each raster, odd-numbered dots are formed in the main scanning direction, and in the 4th nozzle, even-numbered nozzles are formed.
[0143]
By performing such recording, it is possible to disperse the sub-scanning error within each raster, so that the image quality can be further improved. In other words, after forming the raster dot of the 5th nozzle, the sub-scan is performed several times and then the remaining dots of the raster are formed by the 4th nozzle. In some cases, the dots constituting each raster are arranged in a line in the main scanning direction. Probabilistically, the average error in the sub-scanning direction of each raster is often small. Therefore, the image quality in extended printing can be improved.
[0144]
Various methods can be used for intermittently forming the dots of each raster in the two main scans. As shown in FIG. 37, the dots formed by the 5th nozzle and the 4th nozzle The positions in the main scanning direction may be unified, or both may be formed in a checkered pattern as shown in FIG. Of course, other various patterns are applicable. Further, not only two main scans, but also each raster may be formed by three or more main scans.
[0145]
(4) Dot formation control in the third embodiment
Next, dot formation according to the third embodiment will be described. The printer 22 in the third embodiment has the same hardware configuration as that of the first embodiment shown in FIGS. Also, the flow of processing when forming dots is the same as in the first embodiment (FIGS. 13 and 14). In the third embodiment, for convenience of explanation, a case where six nozzles are provided with a nozzle pitch of 4 rasters will be described as an example. Needless to say, the present invention can be applied to other nozzle pitches and nozzle numbers.
[0146]
FIG. 39 is an explanatory diagram showing how dots are formed in the third embodiment. FIG. 40 is an explanatory diagram showing the correspondence of rasters formed by the nozzles in each main scan.
[0147]
In the third embodiment, standard printing processing is performed by feeding paper for three rasters (main scans P1 to P8 in FIG. 39). As is apparent from FIG. 39, in this embodiment, each raster is formed by two main scans. That is, dots are recorded by an overlap method with a scan repetition number of two. The recording method in the overlap method is as described above with reference to FIG.
[0148]
In the third embodiment, as shown in FIG. 39, standard printing is performed by the overlap method with two scan repetitions by feeding three rasters (main scans P1 to P8). Similarly to the first embodiment, this feed amount is set to a feed amount at which the nozzles can be used most effectively among the feed amounts that can form an image without causing raster loss in the interlace method. Naturally, each raster is set to be formed by different nozzles.
[0149]
After standard printing is completed, transitional feed for two rasters is performed as an intermediate process, dots are formed (main scan P9), and an image is formed by fine feed for each raster (main scans P10 to P16). . Also in this case, each raster is formed by two main scans. After executing the intermediate process, a transitional feed for 13 rasters is performed, and an extended printing process is performed by a fine feed for each raster. At this time, each raster is formed by the main scanning twice by the first nozzle and the second nozzle.
[0150]
According to the printing apparatus described above, as described above, by applying intermediate processing and extended printing processing, not only can an area for forming an image be expanded, but also dot recording by an overlap method can be performed. By doing so, a higher quality image can be obtained.
[0151]
In the third embodiment, a case has been shown in which recording is performed by the overlap method while performing minute feed by one raster in the extended print area. The feed amount in the extended print area is not limited to the minute feed, and various settings can be made. In such a case, as shown in the second and third aspects of the first embodiment, the spatial frequency due to the variation in the spacing between the rasters may be set to be sufficiently higher than 1 cycle / mm. Is possible. If it is intended to realize such printing by sub-scanning with a constant feed amount, a condition other than “k · s ± 1” can be obtained under the condition that “nozzle number / scan repetition number s” and nozzle pitch k are relatively prime. What is necessary is just to set the number of nozzles so that it may become a value. At this time, if the sub-scan is performed with a feed amount of “number of nozzles / scan repetition number s”, the adjacent rasters are continuously formed as in the second and third modes of the first embodiment. Can be reduced.
[0152]
(5) Other aspects
In the printers of the embodiments described above, a constant feed amount is used in the standard processing, but so-called irregular feed may be applied in which one cycle is configured by a combination of different feed amounts. An example of such irregular feeding is shown in FIG. FIG. 41 is an explanatory diagram showing how dots are recorded by a head having 8 nozzles at a nozzle pitch of 4 rasters. Unlike the above-described embodiment, one cycle is composed of “5 rasters, 2 rasters, 3 rasters, 6 rasters”, and an image is formed with two scan repetitions. In addition, for the printers of the above-described embodiments, various feed amounts can be set in standard processing, intermediate processing, and extended printing processing.
[0153]
In addition, the following various aspects are also possible. For example, in the above-described embodiment, in the standard printing process, printing is performed from the upper end of the image with a feed amount with a constant cycle. However, when an image is recorded by the interlace method, the example shown in FIG. As is apparent, an area in which no image can be recorded (an unprintable area) occurs at the upper end portion. Therefore, in the vicinity of the upper end, the sub-scan may be executed with a feed amount different from the so-called upper end process, that is, the feed amount in the standard process.
[0154]
An example of such upper end processing is shown in FIG. This is an example of the upper end process performed prior to the irregular feed shown in FIG. As shown in FIG. 42, before the irregular feed is executed, seven sub-scans are executed with a constant feed amount of 3 rasters, and the shift to the irregular feed is performed. When such upper end processing is not executed (FIG. 41), it can be seen that there is a non-printable area corresponding to 23 rasters, but the upper end processing reduces to 18 rasters. The upper end process can be performed in various other ways, and can be applied to the printer 22 of this embodiment.
[0155]
In the above-described embodiment, as described with reference to FIG. 4, the case where the paper feed accuracy is secured by the roller on the paper feed side has been described as an example. It is also applicable when securing. In such a case, contrary to the embodiment shown in FIG. 15 and the like, recording is performed in the order of the extended print area, the intermediate process, and the standard process from the upper end of the area where the image is recorded. In the extended printing area near the upper end, each of the above-described embodiments can be applied.
[0156]
In each of the embodiments described above, extended printing is performed through intermediate processing after standard printing. However, intermediate printing may be omitted, and extended printing may be performed immediately after standard printing. The various embodiments described above can also be applied to the extended print area in such a case.
[0157]
In the printing apparatus of each of the embodiments described above, it has been described that the control (FIGS. 13 and 14) for forming dots is executed by the CPU 41 provided in the printer 22. In this way, the image data output from the printer driver 96 can be in a fixed format without depending on the dot formation method, and there is an advantage that the processing load on the computer 90 is reduced. On the other hand, the data for dot formation in the control routine may be set on the printer driver 96 side. In this case, “dot data to be formed in the first main scan, paper feed amount in the sub-scan, dot data to be formed in the second main scan,...” Are sequentially transferred to the printer 22. Therefore, the image data output from the printer driver 96 changes according to the dot formation method. However, if such a method is adopted, an advantage that the burden on the printer 22 side can be reduced and an advantage that the version can be easily upgraded, that is, a new dot recording method can be realized without changing the PROM 42 or the like of the printer 22. There are advantages that can be done.
[0158]
Since the printing apparatus includes a computer process for controlling the head for recording dots, an embodiment as a recording medium on which a program for realizing the control is recorded can be employed. Such storage media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter printed with codes such as bar codes, computer internal storage devices (such as RAM and ROM). A variety of computer-readable media can be used, such as memory) and external storage devices. In addition, a mode as a program supply apparatus that supplies a computer program for realizing the head control function for performing dot recording described above to a computer via a communication path is also possible.
[0159]
Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various embodiments can be implemented without departing from the spirit of the present invention. In the above-described embodiments, the description has been given of the printer in which the head performs main scanning to form each raster. However, the present invention naturally applies to a printing apparatus that forms a raster without such main scanning, such as a line printer. can do. In the above-described embodiment, a color printer having six colors of ink has been described as an example. However, the present invention does not depend on the number of colors of ink and can be applied to a single-color printer.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printing apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a configuration of software.
FIG. 3 is a schematic configuration diagram of a printer of the present invention.
FIG. 4 is an explanatory diagram illustrating a paper feeding mechanism of the printer of the present invention.
FIG. 5 is an explanatory diagram showing a schematic configuration of a dot recording head of the printer of the present invention.
FIG. 6 is an explanatory diagram illustrating the principle of dot formation in the printer of the present invention.
FIG. 7 is an explanatory diagram showing an example of nozzle arrangement in the printer of the present invention.
FIG. 8 is an enlarged view of the nozzle arrangement in the printer of the present invention and an explanatory diagram showing the relationship with the formed dots.
FIG. 9 is an explanatory diagram for explaining the principle of forming dots having different diameters by the printer of the present invention.
FIG. 10 is an explanatory diagram showing a nozzle driving waveform and a state of dots formed by the driving waveform in the printer of the present invention.
FIG. 11 is an explanatory diagram illustrating an internal configuration of a printer control apparatus.
FIG. 12 is an explanatory diagram showing a state in which a signal for forming dots is sent to the head.
FIG. 13 is a flowchart showing the flow of a dot formation control routine in the present embodiment.
FIG. 14 is a flowchart illustrating a flow of a standard print processing routine in the present embodiment.
FIG. 15 is an explanatory diagram showing how dots are recorded according to the first embodiment;
FIG. 16 is an explanatory diagram showing how dots are recorded according to the first embodiment;
FIG. 17 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the first embodiment.
FIG. 18 is an explanatory diagram showing a state of dot recording according to the prior art.
FIG. 19 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers according to the prior art.
FIG. 20 is an explanatory diagram illustrating the correspondence between main scanning and nozzle numbers and raster numbers in the printer 22 of the present embodiment.
FIG. 21 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the printer 22 of the present embodiment.
FIG. 22 is an explanatory diagram showing a state of error distribution between rasters in dot recording according to the prior art.
FIG. 23 is a graph showing the relationship between spatial frequency and visual intensity.
FIG. 24 is an explanatory diagram showing how dots are recorded according to the second mode of the first embodiment;
FIG. 25 is an explanatory diagram showing correspondence between main scanning and nozzle numbers and raster numbers in the second mode of the first embodiment;
FIG. 26 is an explanatory diagram showing an error distribution between rasters according to the second mode of the first embodiment;
FIG. 27 is an explanatory diagram showing how dots are recorded according to the third mode of the first embodiment;
FIG. 28 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the third mode of the first embodiment;
FIG. 29 is an explanatory diagram showing how dots are recorded when the dot diameter is increased.
FIG. 30 is an explanatory diagram showing a state in which dots having different diameters are recorded together.
FIG. 31 is a graph showing a recording rate when an image is recorded with only small dots.
FIG. 32 is a graph showing a recording rate when an image is recorded using large and small dots.
FIG. 33 is an explanatory diagram showing how dots are recorded according to the second embodiment.
FIG. 34 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the second embodiment.
FIG. 35 is an explanatory diagram showing how dots are recorded according to the third embodiment.
FIG. 36 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the third embodiment.
FIG. 37 is an explanatory diagram showing how dots are recorded when an overlap method is employed.
FIG. 38 is an explanatory diagram showing how dots are recorded according to the second mode when the overlap method is employed.
FIG. 39 is an explanatory diagram showing how dots are recorded according to the fourth embodiment.
FIG. 40 is an explanatory diagram showing the correspondence between main scanning and nozzle numbers and raster numbers in the fourth embodiment.
FIG. 41 is an explanatory diagram showing how dots are recorded by irregular feeding.
FIG. 42 is an explanatory diagram showing an example of upper end processing.
FIG. 43 is an explanatory diagram showing how dots are recorded by the interlace method.
FIG. 44 is an explanatory diagram showing how dots are recorded by the interlace method in the prior art.
FIG. 45 is an explanatory diagram showing how dots are recorded when paper scanning accuracy in sub-scanning is ensured.
FIG. 46 is an explanatory diagram illustrating how dots are recorded when sub-scan paper feed accuracy is not ensured.
[Explanation of symbols]
12 ... Scanner
14 ... Keyboard
15 ... Flexible drive
16. Hard disk
18 ... modem
21 ... Color display
22 Color printer
23 ... Paper feed motor
24 ... Carriage motor
25a: paper feed roller
25b ... driven roller
26 ... Platen
27a: paper discharge roller
27b ... Giza Roller
28 ... Print head
31 ... Carriage
32 ... Control panel
34 ... Sliding shaft
36 ... Drive belt
38 ... pulley
39 ... Position detection sensor
40 ... Control circuit
41 ... CPU
42 ... Programmable ROM (PROM)
43 ... RAM
44 ... PC interface
45. Peripheral input / output unit (PIO)
46 ... Timer
47 ... Transfer buffer
48 ... Bus
51 ... Transmitter
55 ... Distribution output device
61, 62, 63, 64, 65, 66... Ink ejection head
67 ... Introducing pipe
68 ... Ink passage
71 ... cartridge for black ink
72. Color ink cartridge
80 ... Bus
81 ... CPU
82 ... ROM
83 ... RAM
84 ... Input interface
85 ... Output interface
86 ... CRTC
87: Disk controller (DDC)
88 ... Serial I / O interface (SIO)
90 ... Personal computer
91 ... Video driver
92 ... Input section
95 ... Application program
96 ... Printer driver
97 ... Rasterizer
98 ... Color correction module
99 ... Halftone module

Claims (17)

Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head provided with a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction;
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the second sub-scanning unit performs sub-scanning, each raster is formed while performing the sub-scanning with a sub-scanning amount smaller than the average sub-scanning amount by the first sub-scanning unit. first control means for controlling said raster formation unit second subscanning means,
In a first area where sub-scanning is performed by the first sub-scanning means, in a predetermined area not adjacent to the second area where sub-scanning is performed by the second sub-scanning means, adjacent rasters are changed to different nozzles. In the intermediate area adjacent to the predetermined area and the second area, sub-scanning is performed with a feed amount smaller than the predetermined feed amount to form each raster. And a second control means for controlling the raster forming means and the first sub-scanning means . The printing apparatus according to claim 1,
A printing apparatus in which the feed amount by the first control means is one raster. The printing apparatus according to claim 1,
The first control means selects a part of the nozzles provided in the head to form a raster, and an adjacent raster is formed by a different nozzle among the selected nozzles. A printing apparatus that is means for performing sub-scanning. The printing apparatus according to claim 3, wherein
The first control means includes
A printing apparatus which is means for performing sub-scanning with a feed amount in which the fluctuation frequency of the interval between adjacent rasters is significantly greater than 1 cycle / mm. The printing apparatus according to claim 3, wherein
The first control means includes
When the predetermined interval provided with a plurality of nozzles is k dots,
A printing apparatus which is means for performing sub-scanning with a feed amount in which the number of adjacent rasters formed continuously is smaller than k. The printing apparatus according to claim 5, wherein
The first control means includes
When the number of main scans required to form each raster is s,
The number N of the selected nozzles is a value that is relatively prime to k within a range that does not become k · s ± 1,
A printing apparatus which is means for performing sub-scanning with a constant feed amount of N / s. Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head provided with a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction;
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the sub-scan is performed by the second sub-scanning unit, the number of main scans is larger than the number of main scans required to form each raster in the region where the sub-scan is performed by the first sub-scanning unit. First control means for controlling the dot forming means and the second sub-scanning means so as to form each raster ;
In a first area where sub-scanning is performed by the first sub-scanning means, in a predetermined area not adjacent to the second area where sub-scanning is performed by the second sub-scanning means, adjacent rasters are changed to different nozzles. In the intermediate area adjacent to the predetermined area and the second area, sub-scanning is performed with a feed amount smaller than the predetermined feed amount to form each raster. And a second control means for controlling the raster forming means and the first sub-scanning means . Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing apparatus capable of printing an image according to input image data on the print medium by forming a plurality of rasters by
The head is a head capable of forming two or more types of dots having different diameters by a plurality of nozzles provided in the sub-scanning direction for each color,
Raster forming means for driving the head to form the raster;
First sub-scanning means for performing relative movement in the sub-scan with a first accuracy;
Second sub-scanning means for performing the sub-scanning with a second accuracy lower than the first accuracy;
In the region where the second sub-scanning unit performs sub-scanning, the raster forming unit is configured to form dots having a larger diameter at a higher rate than the region where the first sub-scanning unit performs sub-scanning. First control means for controlling ;
In a first area where sub-scanning is performed by the first sub-scanning means, in a predetermined area not adjacent to the second area where sub-scanning is performed by the second sub-scanning means, adjacent rasters are changed to different nozzles. In the intermediate area adjacent to the predetermined area and the second area, sub-scanning is performed with a feed amount smaller than the predetermined feed amount to form each raster. And a second control means for controlling the raster forming means and the first sub-scanning means . A printing apparatus according to any one of claims 1, 7, and 8 ,
The head is provided with p nozzles (p is an integer of 2 or more) at intervals of n rasters (n is an integer of 2 or more) in the sub-scanning direction.
In the intermediate region, the second control means
Sub-scanning is performed with a feed amount that completes an image in an area of m rasters (m is an integer smaller than p × (n−1)) less than the limit raster that can be sub-scanned by the first sub-scanning means. A printing apparatus which is means for controlling the second sub-scanning means. The printing apparatus according to claim 9, wherein
The printing apparatus, wherein the feed amount controlled by the second control unit is a feed amount in which adjacent rasters are formed by different nozzles. The printing apparatus according to claim 9, wherein
A printing apparatus in which the feed amount controlled by the second control unit is one raster. Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing method capable of printing an image corresponding to input image data on the print medium by forming a plurality of rasters by
The head includes a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction,
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the sub-scan movement is performed so that the image is printed by performing the sub-scan with a sub-scan amount smaller than the average sub-scan amount performed with the first accuracy. And controlling the driving of the head ,
In a predetermined area where sub-scanning is performed with the first accuracy but not adjacent to the area where sub-scanning is performed with the second accuracy, the adjacent raster is formed with a predetermined feed amount formed by different nozzles. Sub-scanning is performed, and an image is printed by performing sub-scanning with a feed amount smaller than the predetermined feed amount in an intermediate region adjacent to the predetermined region and the region where sub-scanning is performed with the second accuracy. In this way, the printing method controls the movement of the sub-scan and the driving of the head . Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing method capable of printing an image corresponding to input image data on the print medium by forming a plurality of rasters by
The head includes a plurality of nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction,
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the raster is formed with the number of main scans larger than the number of main scans required to form each raster in the region where the sub-scan is performed with the first accuracy. To control the movement of the sub-scan and the driving of the head ,
In a predetermined area where sub-scanning is performed with the first accuracy but not adjacent to the area where sub-scanning is performed with the second accuracy, the adjacent raster is formed with a predetermined feed amount formed by different nozzles. Sub-scanning is performed, and an image is printed by performing sub-scanning with a feed amount smaller than the predetermined feed amount in an intermediate region adjacent to the predetermined region and the region where sub-scanning is performed with the second accuracy. In this way, the printing method controls the movement of the sub-scan and the driving of the head . Sub-scanning is performed by moving the head relative to the print medium in a fixed direction that intersects the direction in which the raster is formed while forming a raster that is a dot row arranged in one direction of the print medium by the head. A printing method capable of printing an image corresponding to input image data on the print medium by forming a plurality of rasters by
The head includes n (n is an integer of 2 or more) nozzles capable of forming dots of the same color at predetermined intervals in the sub-scanning direction.
In some areas where images are recorded, the sub-scan is performed with a first precision, and in other areas, the sub-scan is performed with a second precision lower than the first precision,
In the region where the sub-scan is performed with the second accuracy, the sub-scan is performed so as to record an image while forming dots having a larger diameter at a higher rate than the region where the sub-scan is performed with the first accuracy. Controlling movement and driving of the head ,
In a predetermined area where sub-scanning is performed with the first accuracy but not adjacent to the area where sub-scanning is performed with the second accuracy, the adjacent raster is formed with a predetermined feed amount formed by different nozzles. Sub-scanning is performed, and an image is printed by performing sub-scanning with a feed amount smaller than the predetermined feed amount in an intermediate region adjacent to the predetermined region and the region where sub-scanning is performed with the second accuracy. In this way, the printing method controls the movement of the sub-scan and the driving of the head . A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In an area where sub-scanning is performed with the second accuracy,
A function of outputting a control signal for performing the sub-scanning with a sub-scanning amount smaller than an average sub-scanning amount performed with the first accuracy;
A region in which sub-scanning is performed with the first accuracy,
In a predetermined region that is not adjacent to a region where sub-scanning is performed with the second accuracy, sub-scanning is performed with a predetermined feed amount that forms adjacent rasters with different nozzles, and the predetermined region and the second accuracy A function of outputting a control signal for performing sub-scanning with a feed amount smaller than the predetermined feed amount in an intermediate region adjacent to a region where sub-scanning is performed ;
Recording medium control signal recorded a possible program realized by a computer and a function of outputting in the order corresponding to the sub-scanning to form an image. A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In the region where sub-scanning is performed with the second accuracy, each raster is scanned at a number of main scans greater than the number of main scans required to form each raster in the region where sub-scanning is performed with the first accuracy. A function to output control signals to form,
A region in which sub-scanning is performed with the first accuracy,
In a predetermined region that is not adjacent to a region where sub-scanning is performed with the second accuracy, sub-scanning is performed with a predetermined feed amount that forms adjacent rasters with different nozzles, and the predetermined region and the second accuracy In the intermediate area adjacent to the area where the sub-scan is performed, a recording medium recording a program capable of being realized by a computer with a function of outputting a control signal for performing the sub-scan with a feed amount smaller than the predetermined feed amount . A recording medium in which a program for printing an image on a printing medium by a printing apparatus is recorded in a computer-readable manner,
Of the area where the image is recorded, a first area where the relative movement in the sub-scanning can be performed with a first precision, and a second area where the sub-scanning is performed with a second precision lower than the first precision. A function for determining the area of 2;
In the region where the sub-scan is performed with the second accuracy, a control signal is output so that dots having a larger diameter are formed at a higher rate than the region where the sub-scan is performed with the first accuracy. function and,
A region in which sub-scanning is performed with the first accuracy,
In a predetermined region that is not adjacent to a region where sub-scanning is performed with the second accuracy, sub-scanning is performed with a predetermined feed amount that forms adjacent rasters with different nozzles, and the predetermined region and the second accuracy In the intermediate area adjacent to the area where the sub-scan is performed, a recording medium recording a program capable of being realized by a computer with a function of outputting a control signal for performing the sub-scan with a feed amount smaller than the predetermined feed amount .

Images