JP2010005981A - Printing method, and printing program - Google Patents

Abstract

High density printing is performed at high speed.
For a dot on a recording medium for which an ink discharge instruction amount is equal to or greater than a first predetermined value, the discharge instruction amount is divided into a first discharge amount and a second discharge amount and Discharge operations (first discharge operation and second discharge operation) are performed at different timings. At this time, different nozzles are used for the respective ejection operations. As a result, since the ink ejected in the first ejection operation is fixed before the second ejection operation, it is possible to perform a plurality of ejection operations on the same dot without temporarily stopping the printing operation. Become. Further, since the ink density is high, banding does not stand out.
[Selection] Figure 8

Description

  The present invention relates to a printing method, a printing program, and the like that can perform high-density printing at high speed.

  Conventionally, various printing techniques for forming an image by ejecting ink onto a recording medium have been proposed. When a high-detail photographic image is formed, a photographic paper (for example, glossy paper, semi-glossy paper, silk paper, etc.) having an ink absorbing layer is used as a recording medium. There are mainly pigment-based inks and dye-based inks for printing devices. Pigment-based inks are less bleedable for printing, so printing on plain paper that only prints black characters is used. Often used as ink for black characters. Also, the fixing property to the recording medium is different between the pigment-based ink and the dye-based ink (the fixing time is long because the pigment-based ink has a lower fixing property than the dye-based ink). Therefore, when printing a photographic image in which black and non-black colors are mixed (for example, a color photograph) on photographic paper such as glossy paper, glossiness unevenness occurs when pigment-based ink and dye-based ink are used simultaneously. Therefore, the pigment-based ink is not suitable for use in image formation on photographic paper such as glossy paper. Therefore, for example, when printing black, a black color is created by mixing dye-based inks of a plurality of other colors (for example, cyan, magenta, and yellow). At this time, in order to create a dark black color, it is necessary to eject a large number of inks of a plurality of colors for one dot. However, if many inks are ejected onto a single dot, even if the dye-based ink has better fixability than the pigment-based ink, if the amount of ink ejected onto the recording medium increases, the ink will be recorded. It takes time until the toner image is fixed on the medium, and the ink bleeds. In this regard, Japanese Patent Application Laid-Open No. 2004-228561 describes that the subsequent printing operation is temporarily stopped until the previously ejected ink is fixed on the recording medium.

JP-A-7-52372

  Temporarily stopping the printing operation as in Patent Document 1 is not desirable from the viewpoint of improving the printing speed. Further, when the discharge amount of the plurality of colors of ink is reduced in order to shorten the time for fixing the discharged ink or to prevent the ink from bleeding, a dark black color cannot be created.

  SUMMARY An advantage of some aspects of the invention is to provide a printing method, a printing program, and the like that can perform high-density printing at high speed.

  According to a first aspect of the present invention, in the printing method for forming an image on a recording medium by ejecting a discharge instruction amount of ink using a plurality of nozzles, the ink discharge instruction amount is the first. A dot on the recording medium that is equal to or greater than a predetermined value is identified, and the ink ejection instruction amount for the identified dot is divided into a first ejection amount and a second ejection amount, and the ink for the identified dot The discharge operation is divided into a first discharge operation and a second discharge operation, and in the first discharge operation, the ink is discharged from the first nozzle to the specified dot by the first discharge amount, In the second ejection operation, after the first ejection operation and after the recording medium is transported by a predetermined amount, the ink is ejected from the second nozzle different from the first nozzle with respect to the specified dot. To the second discharge Characterized in that only discharge.

  According to the printing method, for the dots on the recording medium in which the ink discharge instruction amount is equal to or greater than the first predetermined value, the discharge instruction amount is divided into the first discharge amount and the second discharge amount. Two discharge operations (first discharge operation and second discharge operation) are performed at different timings. At this time, different nozzles are used for the respective ejection operations. As a result, since the ink ejected in the first ejection operation is fixed before the second ejection operation, it is possible to perform a plurality of ejection operations on the same dot without temporarily stopping the printing operation. Become. Further, since the ink density increases as the ink discharge amount increases by a plurality of discharge operations, banding does not stand out.

  The invention according to Claim 2 which is one aspect of the present invention is the printing method according to Claim 1, wherein the ink is a plurality of inks having different colors, and the plurality of nozzles are provided for each ink. The dots on the recording medium that are arranged and the total amount of the discharge instruction amounts of the respective inks are equal to or greater than the first predetermined value are specified, and the discharge instruction amounts of the respective inks corresponding to the specified dots are determined as the first discharge It is characterized by dividing into an amount and a second discharge amount.

  According to the above printing method, when another color (for example, black) is formed using a plurality of inks of different colors, the total amount of the discharge instruction amounts of the respective inks is equal to or greater than the first predetermined value. For each dot on the recording medium, each ink discharge instruction amount is divided into a first discharge amount and a second discharge amount, and two discharge operations (first discharge operation and second discharge operation) are performed at different timings. To do. At this time, a different nozzle is used for each ink in each ejection operation. Thereby, since the ink ejected in the first ejection operation is fixed before the second ejection operation, the ejection operation can be performed a plurality of times on the same dot without temporarily stopping the printing operation. Further, since the ink density increases as the ink discharge amount increases by a plurality of discharge operations, banding does not stand out.

  The invention according to claim 3, which is an aspect of the present invention, is the printing method according to claim 2, wherein when the printing accuracy of a printing apparatus using the printing method is acquired and the printing accuracy is determined to be low, When one of the first discharge amount and the second discharge amount of each ink is set to zero and it is determined that the printing accuracy is high, the ink whose discharge instruction amount is larger than a second predetermined value is Both the first discharge amount and the second discharge amount are non-zero, and the sum of the first discharge amounts of the respective inks and the sum of the second discharge amounts of the respective inks do not exceed the first predetermined value. It is characterized by determining as follows.

  According to the printing method, the printing accuracy of a printing apparatus that uses the printing method is acquired, and the ejection amount in the first ejection operation and the second ejection operation is determined according to the printing accuracy. As a result, when the printing accuracy is low, the ejection operation for one ink is limited to one time. Therefore, it is possible to prevent the image quality from being deteriorated due to the deviation of the landing position in the two ejection operations. In addition, when the printing accuracy is high, the ink ejection operation in which the ink ejection amount is larger than the second predetermined value is divided into two ejection operations, so that the ink fixing speed is improved and the image quality is improved. In addition, since the sum of the first ejection amounts of the respective inks and the sum of the second ejection amounts of the respective inks are determined so as not to exceed the first predetermined value, the first ejection operation is performed. The ejected ink can be reliably fixed by the second ejection operation.

  The invention according to claim 4, which is an aspect of the present invention, is a printing program for executing a printing method for forming an image on a recording medium by ejecting a discharge instruction amount of ink using a plurality of nozzles. Specifying the dots on the recording medium in which the discharge instruction amount is equal to or greater than a first predetermined value, and dividing the ink discharge instruction amount for the specified dots into a first discharge amount and a second discharge amount A step of dividing the ink ejection operation with respect to the identified dot into a first ejection operation and a second ejection operation; and as the first ejection operation, the ink is ejected from the first nozzle with respect to the identified dot. The step of discharging from the first discharge amount and the second discharge operation after the first discharge operation and after the recording medium is transported by a predetermined amount, the ink is specified. To dots, characterized in that to perform the step of discharging only the second ejection amount different from the second nozzle and said first nozzle.

  According to the printing program, for the dots on the recording medium in which the ink discharge instruction amount is equal to or greater than the first predetermined value, the discharge instruction amount is divided into the first discharge amount and the second discharge amount. Two discharge operations (first discharge operation and second discharge operation) are performed at different timings. At this time, different nozzles are used for the respective ejection operations. As a result, since the ink ejected in the first ejection operation is fixed before the second ejection operation, it is possible to perform a plurality of ejection operations on the same dot without temporarily stopping the printing operation. Become. Further, since the ink density increases as the ink discharge amount increases by a plurality of discharge operations, banding does not stand out.

  The invention according to claim 5, which is an aspect of the present invention, is the printing program according to claim 4, wherein the ink is a plurality of inks having different colors, and the plurality of nozzles are provided for each ink. A step of specifying the dots on the recording medium that are arranged and the total amount of the discharge instruction amounts of the respective inks is equal to or more than the first predetermined value; The computer is caused to execute a step of dividing into an amount and a second discharge amount.

  According to the printing program described above, when other colors (for example, black) are formed using a plurality of inks of different colors, the total amount of ink discharge instruction amounts is equal to or greater than the first predetermined value. For each dot on the recording medium, each ink discharge instruction amount is divided into a first discharge amount and a second discharge amount, and two discharge operations (first discharge operation and second discharge operation) are performed at different timings. To do. At this time, a different nozzle is used for each ink in each ejection operation. Thereby, since the ink ejected in the first ejection operation is fixed before the second ejection operation, the ejection operation can be performed a plurality of times on the same dot without temporarily stopping the printing operation. Further, since the ink density increases as the ink discharge amount increases by a plurality of discharge operations, banding does not stand out.

  The invention according to claim 6, which is an aspect of the present invention, is the printing program according to claim 5, the step of obtaining the printing accuracy of a printing apparatus using the printing method, and when the printing accuracy is determined to be low, The step of setting either the first discharge amount or the second discharge amount to zero for each of the inks, and the ink whose discharge instruction amount is greater than a second predetermined value when it is determined that the printing accuracy is high The step of setting both the first discharge amount and the second discharge amount to non-zero, the sum of the first discharge amounts of the respective inks, and the sum of the second discharge amounts of the respective inks are all the first. The computer is caused to execute a step of determining not to exceed a predetermined value.

  According to the printing program, the printing accuracy of the printing apparatus using the printing method is acquired, and the ejection amount in the first ejection operation and the second ejection operation is determined according to the printing accuracy. As a result, when the printing accuracy is low, the ejection operation for one ink is limited to one time. Therefore, it is possible to prevent the image quality from being deteriorated due to the deviation of the landing position in the two ejection operations. In addition, when the printing accuracy is high, the ink ejection operation in which the ink ejection amount is larger than the second predetermined value is divided into two ejection operations, so that the ink fixing speed is improved and the image quality is improved. In addition, since the sum of the first ejection amounts of the respective inks and the sum of the second ejection amounts of the respective inks are determined so as not to exceed the first predetermined value, the first ejection operation is performed. The ejected ink can be reliably fixed by the second ejection operation.

  According to the present invention, high density printing can be performed at high speed.

  A system for realizing a printing method according to an embodiment of the present invention will be described below. The present invention can also be realized as a printing program for causing a computer to execute the printing method described below. Furthermore, the present invention can also be realized as a printing apparatus that executes a printing method described below.

  FIG. 1 is an example of a system configuration for realizing a printing method according to an embodiment of the present invention. As shown in FIG. 1, this system includes a computer 100, a printer 200, and a relay device 300.

The computer 100 and the printer 200 are connected via the relay device 300. The computer 100 and the printer 200 exchange various information. The printer 200 performs printing in response to an instruction from the computer 100. The computer 100 and the printer 200 have identification information (for example, an IP address). The computer 100 executes a program for main processing described later.
Even if the computer 100 and the printer 200 are directly connected using a connection technology such as USB (Universal Serial Bus) without using the relay device 300, various types of information can be similarly transmitted and received.

  In the example shown in FIG. 1, the number of computers 100 is one, but it goes without saying that a configuration including a plurality of computers 100 may be used. In the example illustrated in FIG. 1, the number of printers 200 is one, but a configuration including a plurality of printers 200 may be used.

  Further, the printer 200 may perform some or all of various processes executed by the computer 100. That is, as long as it has a processor capable of executing a predetermined program and storage means capable of temporarily and permanently storing various information, it can of course be used as a computer in this embodiment. Moreover, you may comprise so that the one part or all part of the various processes demonstrated below may be performed in the external apparatus connected with the network.

  Of course, this embodiment may be realized by distributed processing by a plurality of computers. Further, a specialized processor and / or memory may be used to execute this embodiment.

The computer 100 basically includes a processor, first storage means, and second storage means. Needless to say, various elements may be added as necessary.
The first storage means is constituted by, for example, a nonvolatile memory. The first storage means stores various programs including programs necessary for realizing the present invention. Various data necessary for realizing the present invention is also stored in the first storage means.
The second storage means is composed of, for example, a volatile memory. The second storage means is loaded with a program or data stored in the first storage means.
The processor executes various processes using data stored in the first storage unit and the second storage unit. It also controls the operation and signal flow of various devices connected to the processor.

  FIG. 2 is a block diagram illustrating an example of the internal configuration of the computer 100. As illustrated in FIG. 2, the computer 100 includes a CPU 11, a ROM 12, a RAM 13, and a communication I / F 14. The CPU 11 executes various programs (described later) in order to realize the present invention. These programs are stored in the ROM 12. These programs can function as drivers. In executing the program, various data are read / written to / from the RAM 13. The computer 100 transmits predetermined information to the printer 200 via the communication I / F 14. Further, each of the above elements is connected to each other by a signal line. Note that the internal configuration shown in FIG. 2 is merely an example, and it goes without saying that the present invention is not limited to the configuration having this internal configuration.

FIG. 3 is an external perspective view of the printer 200. The printer 200 may be realized as a multi-function device (MFD) having a copy function, a scanner function, a facsimile function, and a cordless telephone function in addition to the function for executing the present invention.
The printer 200 can be connected to a telephone communication network, and can print an image or document on a recording medium based on image data or document data transmitted from another device. The printer 200 is connected to an external device such as a digital camera and can record image data output from the digital camera on a recording medium.

  As shown in FIG. 3, the printer 200 is formed by a main body case (housing) 201 made of synthetic resin. Further, a paper feed cassette 202 is formed on the front surface of the printer 200 so that it can be inserted and removed. A paper discharge unit 203 is disposed above the paper feed cassette 202.

  In addition, a slot unit 204 is arranged on the front surface of the printer 200. When various storage media such as a memory card are loaded in the slot unit 204, image data stored in the storage medium can be printed. Is possible.

  An operation panel unit 205 including various operation buttons, a liquid crystal display unit, and the like is provided on the upper side of the printer 200.

  A carriage is provided inside the printer 200. An ink cartridge and a print head are mounted on the carriage. The ink cartridge is detachable from the carriage. Further, the ink cartridge and the print head may be directly connected, and the ink of the ink cartridge can be supplied to the printer head through the ink supply pipe. The carriage is controlled in position in the main scanning direction (X direction in FIG. 3) by a driving belt driven by a driving motor.

  In addition, a paper feed mechanism is provided inside the printer 200. The paper feed mechanism can transport the recording medium in the sub-scanning direction (Y direction in FIG. 3).

  Since the configurations and operations of the carriage and the paper feed mechanism are known (for example, Japanese Patent Application Laid-Open No. 2007-268811), detailed description thereof is omitted.

  Next, the internal configuration of the printer 200 will be described. FIG. 4 is a block diagram illustrating an internal configuration of the printer 200. As shown in FIG. 4, the printer 200 includes a CPU 21, a ROM 22, a RAM 23, an input / output I / F 24, a communication I / F 25, and a printing mechanism 26. The CPU 21 can execute all or part of a program for realizing the present invention. At this time, the program executed by the CPU 21 is stored in the ROM 22. In executing the program, various data are read / written to / from the RAM 23. Via the input / output I / F 24, display control of the liquid crystal display unit and transmission / reception of information to / from an input device (such as a touch panel provided on the LCD surface) are performed. The printer 200 transmits and receives various information to and from the computer 100 via the communication I / F 25. The image data is printed using the printing mechanism 26. Each of the above elements is connected to each other by a signal line. Note that the internal configuration shown in FIG. 4 is merely an example, and it goes without saying that the present invention is not limited to the configuration having this internal configuration.

  Next, the flow of processing in the computer 100 and the printer 200 will be described. FIG. 5 shows a processing flow in the computer 100 and the printer 200.

  When receiving a print instruction from a predetermined application, the computer 100 acquires print data corresponding to the print instruction.

  Thereafter, the acquired print data is converted into CMY data (pixel density value) by color conversion processing. Thereby, each pixel can be converted into, for example, density values of C (cyan), M (magenta), and Y (yellow). In addition, for each color, multi-value data with 256 gradations can be obtained. In the color conversion process, a known technique such as a color matching process can be applied. Further, the density value of each pixel can be expressed as (C, M, Y) = (150, 30, 200), for example. Note that the data may be data in a color space (RGB, Lab, etc.) other than CMY.

Thereafter, a basic discharge amount table is created based on the CMY data by error diffusion processing. The basic discharge amount table defines the discharge amount of each color ink in each pixel. Further, the discharge amount can be set to, for example, four values (large, medium, small, and none). In the following description, the relative value of the discharge amount is
“Large / Medium / Small / None” = “4.2.1.0”
And The ink ejection amount in each pixel can be expressed as (C, M, Y) = (2, 1, 4).

Thereafter, the basic discharge amount table is divided into a first discharge amount table and a second discharge amount table by table division processing. Details of the data division processing will be described later.
Thereafter, the computer 100 transmits the first discharge amount table and the second discharge amount table to the printer 200.
The printer 200 performs discharge processing based on the received first discharge amount table and second discharge amount table. Details of the discharge processing based on the discharge amount table will be described later.

Next, the print head included in the printer 200 will be described. FIG. 6 is a schematic diagram of a print head of the printer 200.
As shown in FIG. 6, the print head has a plurality of nozzles for each color. The nozzles for each color are arranged in a staggered pattern. Here, a head in which nozzles are linearly arranged requires higher manufacturing accuracy than a head in which nozzles are arranged in a staggered manner. Therefore, with the same manufacturing accuracy, a head with nozzles arranged in a staggered pattern can shorten the interval of nozzle arrangements compared with a head with nozzles arranged in a straight line, so that the printing resolution can be increased. In addition, the head can be reduced in size.
For applications where resolution is not important, even if the nozzles for each color are arranged in a straight line, the same effect as in a staggered arrangement can be obtained.

  Moreover, the number of nozzles of each color can be set to 90, for example. In the following description, each nozzle may be referred to as a nozzle (n) (see FIG. 6). Further, the nozzle (1) to the nozzle (45) may be referred to as a main nozzle, and the nozzle (46) to the nozzle (90) may be referred to as a sub nozzle.

Further, the nozzle interval can be set to 150 dpi (75 dpi in the linear direction).
The ink color may be other colors. The number of nozzles may be other numbers. Further, even when the number of nozzles is 90, the number of main nozzles and sub nozzles may be 37, for example.
Here, in order to make the transport amount to the recording medium in the sub-scanning direction constant, the number of main nozzles used (number of sub-nozzles) needs to be an odd number. This is because if the number of nozzles is an odd number, the nozzle interval is an even number and can be divided by an integer.

By ejecting ink using a plurality of nozzles for each color, it is possible to eject ink in a plurality of rows in one main scan (carriage feed). Further, the conveyance amount of the recording medium in the sub-scanning direction can be made constant.
For example, when ink is ejected from 45 nozzles, the transport amount can be made constant by transporting “45/2400” inches in the sub-scanning direction. To generalize this, in order to form an image quality with a resolution of “M (dpi)” with N nozzles, it is necessary to convey in the sub-scanning direction by “N / M” inches.

  When an image quality of 2400 dpi is formed on a recording medium using a print head having a resolution of 150 dpi (see FIG. 6), 16 times (2400/150) of an area having a width of (1/150) inch is used. It is necessary to eject ink by main scanning.

  Next, how ink is ejected and transported using a plurality of nozzles will be described. FIG. 7 is a schematic diagram showing how ink is ejected and transported using a plurality of nozzles. In order to simplify the description, a print head having nozzle (1), nozzle (2), nozzle (3) as main nozzles, nozzle (4), nozzle (5), and nozzle (6) as sub nozzles will be described. Ink ejection for one color of CMY will be described, but the same ink ejection operation is performed for each color ink.

In the following description, it is assumed that the image quality is four times higher than the nozzle interval. Further, the nozzle interval is (75) dpi, and the resolution for a recording medium with three nozzles is 300 dpi (1 inch = 300 dots).
In FIG. 7, if the transport amount in the sub-scanning direction is “3 (number of nozzles) / 300 (dpi)” inches, the transport amount in the sub-scanning direction is constant. Further, since 1 inch = 300 dots, 3 dots are conveyed in one sub-scan.

  In FIG. 7, the recording medium ejects four columns of ink in each row. In FIG. 7, the number of lines is shown in italics on the left of each recording medium. Further, “N (M)” in the recording medium indicates that “ink was ejected by the nozzle (M) in the Nth pass”.

  For example, in the third pass, ink is ejected by the nozzle (1) to the 10th line of the recording medium. In the third pass, ink is ejected by the nozzle (2) to the sixth line of the recording medium. In the third pass, ink is ejected from the second row of the recording medium by the nozzle (3).

  Thereafter, the recording medium is conveyed by 3/300 inch (3 dots), and ink is ejected by the nozzle (1) to the 13th row of the recording medium in the fourth pass. In the fourth pass, ink is ejected by the nozzle (2) to the ninth line of the recording medium. In the fourth pass, ink is ejected by the nozzle (3) to the fifth row of the recording medium.

  Thereafter, the recording medium is conveyed by 3/300 inch (3 dots), and ink is ejected by the nozzle (1) to the 16th line of the recording medium in the fifth pass. In the fifth pass, ink is ejected by the nozzle (2) to the 12th row of the recording medium. In the fifth pass, ink is ejected by the nozzle (3) to the eighth line of the recording medium.

  Thereafter, the recording medium is conveyed by 3/300 inch (3 dots), and ink is ejected by the nozzle (1) to the 19th line of the recording medium in the sixth pass. Further, in the sixth pass, ink is ejected by the nozzle (2) to the 15th line of the recording medium. In addition, ink is ejected by the nozzle (3) to the 11th row of the recording medium in the sixth pass.

  By repeating the above operations, it is possible to form an image with a desired resolution while uniformly feeding the recording medium in the sub-scanning direction.

Further, the printer 200 determines “how much” ink is to be ejected to each nozzle at what timing based on the received ejection amount table.
At this time, based on the data “discharge the relative amount L of ink in the J row and K column of the recording medium”, the data “discharge the relative amount L of ink to the Kth in the Nth pass” is obtained. (Hereinafter, expressed in the form of (N, K, L), sometimes referred to as nozzle data). Based on the generated nozzle data, the operation of each nozzle is controlled.

For example, in the example shown in FIG. 7, “ejection of a relative amount of 2 ink” in the second row and first column of the recording medium
“Discharge 4 relative amount of ink” in the second column,
In the third column, “relative amount of 0 ink is ejected”,
In the fourth row, “relative amount of 1 ink is ejected”,
Is received as the discharge amount data of the nozzle (3),
(3, 1, 2)
(3, 2, 4)
(3, 3, 0)
(3, 4, 1)
Is generated.

  The nozzle data described above is merely an example, and any data for controlling each nozzle may be used, and the present invention is not limited to the one using the nozzle data described above. Absent.

  Next, main processing executed by the computer 100 will be described. FIG. 8 is a flowchart of the main process. The main process is executed by receiving a print instruction from a predetermined application. In the following description, it is assumed that the main process is executed for each page of data.

In S11, print data corresponding to the print instruction is acquired (see FIG. 5).
In S12, color conversion processing is executed on the acquired print data (see FIG. 5).
Error diffusion processing is performed on the CMY data that has undergone color conversion in S13 (see FIG. 5). Thereafter, the process proceeds to S14.

  The processing of S14 to S19 described below is performed for each pixel stored in the basic ejection amount table, and the processing of S14 to S19 corresponds to the “data division processing” in FIG.

  In S14, the total amount of ejection per dot is calculated. For example, when the ink discharge amount (data in the basic discharge amount table) at a certain pixel is (C, M, Y) = (4, 1, 2), the total discharge amount of the pixel is “7”. Become.

  In S15, it is determined whether to divide the ejection operation for the pixel. Specifically, if the total discharge amount calculated in S14 is equal to or greater than a predetermined amount, the determination in S15 is “YES”. Moreover, this predetermined amount can be set to "9", for example. The predetermined amount is an amount that may cause uneven drying of ink on the recording medium, and can be obtained by experiments or the like.

  When it is determined that the discharge operation is not divided (S15: NO), the process proceeds to S16. In S16, the basic discharge amount table data is copied to the first discharge amount table. The process of S16 will be described below.

  FIG. 9 is an explanatory diagram of a basic discharge amount table, a first discharge amount table, and a second discharge amount table. In order to simplify the description, a case where ink is ejected in 10 rows and 4 columns on a recording medium will be described. In FIG. 9, for example, the dot data in the fifth row and third column of the basic discharge amount table is (C, M, Y) = (4, 1, 2) (that is, the total amount “7” is a predetermined amount). Is smaller than “9”), the data is copied to the dot data in the fifth row and third column of the first ejection amount table. Further, nothing is copied to the dot data in the fifth row and third column of the second ejection amount table, so the initial value (0, 0, 0) remains unchanged.

  On the other hand, when it is determined in S15 that the discharge operation is divided (S15: YES), the process proceeds to S17. In S17, the basic discharge amount table data is divided into first data and second data. A method of dividing the basic discharge amount table data will be described below.

  For example, when the ink discharge amount (data in the basic discharge amount table) in a certain pixel is (C, M, Y) = (4, 2, 4) (the total amount of discharge amount is 10), The data is divided into first data = (4, 2, 0) and second data = (0, 0, 4). As a result, the total discharge amount in the first data is “6”, and the total discharge amount in the second data is “4”. Therefore, the total discharge amount in each data is smaller than the predetermined amount “9”. The above-described division method is merely an example. For example, the first data = (4, 0, 4) and the second data = (0, 2, 0) may be used.

  In S18, the first data is copied to the first discharge amount table. In S19, the second data is copied to the second ejection amount table.

  In this regard, in FIG. 9, the dot data in the seventh row and the second column of the basic discharge amount table is (C, M, Y) = (4, 2, 4), and is the first data (C, M, Y) = (4, 2, 0) is copied to the dot data in the seventh row and the second column of the first ejection amount table. Further, the second data (C, M, Y) = (0, 0, 4) is copied to the dot data in the seventh row and the second column of the second ejection amount table.

  In S20, it is determined whether or not processing has been performed for all dots. If it is determined that processing has not been performed for all dots (S20: NO), the process returns to S14, and the above-described processing is performed on unprocessed pixels. On the other hand, if it is determined that processing has been performed for all dots (S20: YES), the process proceeds to S21.

  In S21, the first discharge table and the second discharge table are transmitted to the printer 200. The printer 200 performs a discharge process based on the received first discharge table and second discharge table.

  Next, the discharge process will be described. In the discharge process, both the main nozzle and the sub nozzle are used. In the print head shown in FIG. 6, for example, nozzle data is created for nozzle (1) to nozzle (45) based on the first ejection amount table. Further, nozzle data is created for the nozzle (46) to the nozzle (90) based on the second discharge amount table. At this time, the nozzle (n) of the main nozzle is associated with the nozzle (n + 45) of the sub nozzle.

  Thereby, when the pixel position discharged using the nozzle (1) is conveyed to the nozzle (46), the second discharge operation is performed using the nozzle (46) at the pixel position. That is, two ink ejection operations are performed at different timings on the same pixel position.

  The two ink ejection operations will be described in detail. FIG. 10 is a schematic diagram showing how ink is ejected and transported using a plurality of nozzles. In FIG. 10, it is assumed that the total amount of ink ejected from the pixel in the 9th row and the 3rd column (hereinafter referred to as “target pixel”) is equal to or greater than a predetermined amount.

  At this time, the first ink discharge is performed on the target pixel by the nozzle (2) which is the main nozzle in the fourth pass. Thereafter, the second ink discharge is performed on the target pixel by the nozzle (5) which is the sub nozzle in the eighth pass. Further, since there is a time difference between the fourth-pass ejection operation and the eighth-pass ejection operation, the ink ejected by the first ink ejection operation is fixed on the recording medium by the second ink ejection operation. . Thereby, it is possible to prevent the ink from bleeding at the target pixel. In addition, since the amount of ejected ink is large, banding does not stand out and print quality does not deteriorate.

(Another method of division)
In the above-described embodiment, each color ink is ejected by only one of the first ink ejection operation and the second ink ejection operation (hereinafter referred to as “first division method”). . However, for example, when the ink discharge amount (data in the basic discharge amount table) in a certain pixel is (C, M, Y) = (4, 2, 4) (the total discharge amount is 10). The data can also be divided into first data = (2, 1, 2) and second data = (2, 1, 2) (hereinafter referred to as “second division method”).
That is, each color ink can be ejected by the first ink ejection operation and the second ink ejection operation.

  Further, the division method can be switched according to the printing accuracy of a printing apparatus using the above-described printing method or a printing apparatus that executes the above-described printing program. When the printing accuracy is low, the first division method can be applied. Thereby, it is possible to prevent deterioration in image quality due to the deviation of the landing position in the two ejection operations. Further, when the printing accuracy is high, the second division method can be applied. Thereby, the ink fixing speed is improved, and the image quality can be improved.

  As described above, according to the present invention, for the dots on the recording medium whose ink discharge instruction amount is equal to or greater than the first predetermined value, the discharge instruction amount is set to the first discharge amount and the second discharge amount. The two discharge operations (first discharge operation and second discharge operation) are performed at different timings. At this time, different nozzles are used for the respective ejection operations. As a result, since the ink ejected in the first ejection operation is fixed before the second ejection operation, it is possible to perform a plurality of ejection operations on the same dot without temporarily stopping the printing operation. Become. Further, since the ink density increases as the ink discharge amount increases by a plurality of discharge operations, banding does not stand out.

  FIG. 11 is an example of a printing result obtained by the printing method described above.

  Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention. The present invention can also be realized as a storage medium in which the above-described printing program is recorded.

It is an example of the system configuration | structure in one Embodiment of this invention. It is a block diagram which shows an example of the internal structure of the computer in one Embodiment of this invention. 1 is an external perspective view of a printer according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of an internal configuration of a printer according to an embodiment of the present invention. It is explanatory drawing which showed the flow of the process in the computer and printer in one Embodiment of this invention. FIG. 2 is a schematic diagram of a print head according to an embodiment of the present invention. It is a schematic diagram which shows the mode of the ink discharge and conveyance using the some nozzle in one Embodiment of this invention. It is a flowchart of the main process in one Embodiment of this invention. It is explanatory drawing of the basic discharge amount table, the 1st discharge amount table, and the 2nd discharge amount table in one Embodiment of this invention. It is a schematic diagram which shows the mode of the ink discharge and conveyance using the some nozzle in one Embodiment of this invention. It is an example of the printing result by the printing method of one Embodiment of this invention.

Explanation of symbols

11 CPU
12 ROM
13 RAM
14 Communication I / F
21 CPU
22 ROM
23 RAM
24 I / O I / F
25 Communication I / F
26 Printing Mechanism 100 Computer 200 Printer

Claims (6)

In a printing method for forming an image on a recording medium by discharging a discharge instruction amount of ink using a plurality of nozzles,
A dot on the recording medium in which the ink discharge instruction amount is equal to or greater than a first predetermined value;
The discharge instruction amount of the ink for the specified dot is divided into a first discharge amount and a second discharge amount,
The ink ejection operation for the identified dots is divided into a first ejection operation and a second ejection operation,
In the first ejection operation, the ink is ejected from the first nozzle by the first ejection amount to the specified dot,
In the second ejection operation, after the first ejection operation and after the recording medium is transported by a predetermined amount, the ink is ejected from the second nozzle different from the first nozzle with respect to the specified dot. From the second discharge amount,
A printing method characterized by the above. The ink is a plurality of inks having different colors,
The plurality of nozzles are arranged for each ink,
Specifying a dot on the recording medium in which the total amount of each ink ejection command is equal to or greater than the first predetermined value;
The discharge instruction amount of each ink for the specified dot is divided into a first discharge amount and a second discharge amount.
The printing method according to claim 1. The printing method according to claim 2,
Get the printing accuracy of the printing device that uses the printing method,
When it is determined that the printing accuracy is low, either the first discharge amount or the second discharge amount of each of the inks is set to zero,
When it is determined that the printing accuracy is high, for the ink whose discharge instruction amount is larger than the second predetermined value, the first discharge amount and the second discharge amount are both non-zero,
The sum of the first ejection amounts of the respective inks and the sum of the second ejection amounts of the respective inks are determined so as not to exceed the first predetermined value.
The printing method according to claim 2. A printing program for causing a computer to execute a printing method for forming an image on a recording medium by discharging a discharge instruction amount of ink using a plurality of nozzles,
Identifying a dot on the recording medium in which the ink ejection command amount is equal to or greater than a first predetermined value;
Dividing the ink discharge instruction amount for the identified dot into a first discharge amount and a second discharge amount;
Dividing the ink ejection operation for the identified dots into a first ejection operation and a second ejection operation;
As the first ejection operation, ejecting the ink by the first ejection amount from the first nozzle to the identified dot;
As the second ejection operation, after the first ejection operation and after the recording medium is transported by a predetermined amount, the ink is ejected from the second nozzle different from the first nozzle with respect to the specified dot. Discharging the second discharge amount from
A print program for executing The ink is a plurality of inks having different colors,
The plurality of nozzles are arranged for each ink,
Identifying a dot on the recording medium in which the total amount of ink ejection instruction amounts is not less than the first predetermined value;
Dividing the discharge instruction amount of each ink for the specified dot into a first discharge amount and a second discharge amount;
The printing program according to claim 4, for causing a computer to execute. Obtaining printing accuracy of a printing apparatus using the printing method;
If it is determined that the printing accuracy is low, the step of setting either the first discharge amount or the second discharge amount of each of the inks to zero;
If it is determined that the printing accuracy is high, for the ink whose discharge instruction amount is larger than a second predetermined value, both the first discharge amount and the second discharge amount are set to non-zero;
Determining the sum of the first ejection amounts of the respective inks and the sum of the second ejection amounts of the respective inks so as not to exceed the first predetermined value;
6. A printing program according to claim 5, for causing a computer to execute.