JP2005186337A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the positional accuracy of an image, which is formed on a front side/backside, by correcting the distortion of the image on the front side/backside, caused by the distortion, shrinkage, etc. of transfer paper. <P>SOLUTION: This image forming apparatus 1 makes adjusted data on a main scanning inclination and a subscanning inclination input from an operation display part 12, depending on the front side/backside and type of the transfer paper, so as to set the input adjusted data in an adjusted file 11f. In the formation of the image, the adjusted data are acquired from the adjusted file 11f depending on the front/backside and type of the transfer paper, and turning processing is applied to image data in accordance with the adjusted data, so that the distortion of the image can be corrected; and the image can be formed on the transfer paper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms images on both sides of a transfer sheet.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic system, a technique (heat fixing method) for fixing an unfixed toner image transferred onto a transfer sheet by heating and melting is known. As the heat fixing method, a planar heater method, an infrared lamp method, and a fixing roller method which is currently most popular are known.

  In an image forming apparatus that uses a heat fixing method to fix a toner image, moisture contained in the transfer paper evaporates due to heat, so that the transfer paper contracts after fixing. The rate of shrinkage (shrinkage rate) varies depending on the type and thickness of the transfer paper. It is empirically known that it takes about 15 to 20 minutes for the transfer paper once shrunk by heat fixing to absorb moisture in the air and return to its original size.

By the way, in general, when an image is formed on both sides of a transfer paper, a toner image is transferred to one side (front surface) of the transfer paper, heated and fixed, and then transferred to the other side (back side) of the transfer paper, It is heat-fixed again. Therefore, when the toner image is transferred to the back surface, the transfer paper is transferred while being contracted, and there is a problem that when the transfer paper returns to the original size, the image sizes on the front surface and the back surface are different. Therefore, a technique is known in which image magnification correction is performed in accordance with the front surface / back surface in order to match the image size and the image forming position of the front surface and the back surface. In addition, there is known an image forming apparatus capable of making the positions and magnifications of the images formed on the front and back surfaces of the transfer paper coincide with each other by simultaneously performing transfer onto both sides of the transfer paper (for example, patents). Reference 1).
JP 11-143333 A

  However, the entire surface of the transfer paper after passing through the fixing unit does not shrink uniformly. Depending on how the transfer paper enters the fixing unit, the transfer paper itself is distorted due to the influence of the crown state of the fixing roller. It may shrink. In such a case, there is a problem that the positions of the front image and the back image cannot be accurately corrected only by uniformly correcting the magnification of the image and correcting the image forming position.

  Further, as a factor for distorting the image formed on the transfer paper, there is a case where the read image is distorted due to an optical lamp mounting error in the scanner unit. In such a case, along with the shrinkage of the transfer paper, it is necessary to perform different distortion correction depending on the front surface and the back surface of the transfer paper. There was a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that corrects front / back image distortion due to distortion shrinkage or the like of transfer paper and improves the positional accuracy of an image formed on the front / back surface.

In order to solve the above problem, the invention according to claim 1
An image forming apparatus including an image forming unit that forms images on both sides of transfer paper based on image data,
An image processing unit that performs processing for correcting distortion of the image data by changing the amount of inclination of the image data in the main scanning direction and the sub-scanning direction;
A control unit that sets the amount of inclination in the main scanning direction and the sub-scanning direction according to the front and back surfaces of the transfer paper, and causes the image processing unit to perform processing for correcting distortion of image data;
It is characterized by having.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect,
The control unit is characterized in that the amount of inclination in the main scanning direction and the sub-scanning direction is set independently for the front and back surfaces of the transfer paper.

The invention according to claim 3 is the image forming apparatus according to claim 1 or 2,
The control unit is characterized in that the inclination amount in the main scanning direction and the sub-scanning direction is set according to an index indicating the characteristics of the transfer paper type.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect,
The index indicating the characteristics of the paper type is an index indicating the characteristics of the paper type including at least one of the material, basis weight, manufacturing method, brand, size, gap direction, and surface roughness of the transfer paper, or a combination thereof. It is an index indicating the characteristics of the paper type.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects,
The control unit is configured to prohibit the image processing unit from correcting image data distortion in accordance with a JOB mode.

  According to the first aspect of the present invention, the distortion of the image data is corrected by changing the amount of inclination of the image in the main scanning direction and the sub-scanning direction according to the front and back surfaces of the transfer paper, and the image is printed on both sides of the transfer paper. Since it can be formed, the positional accuracy of images formed on the front and back surfaces of the transfer paper can be improved.

  According to the second aspect of the present invention, since the front and back surfaces of the transfer paper can be independently set with the amount of inclination in the main scanning direction and the sub-scanning direction, The distortion of the read image due to an attachment error such as the above can be corrected, and for the back surface of the transfer paper, the distortion due to the contraction of the transfer paper can be corrected independently of the distortion of the read image.

  According to the third or fourth aspect of the invention, since the amount of inclination in the main scanning direction and the sub-scanning direction can be set according to the index indicating the characteristics of the detailed transfer paper type, there is a slight difference in the paper type. Therefore, it is possible to accurately correct image distortion caused by a difference in shrinkage rate of the transfer paper.

  According to the fifth aspect of the present invention, it is possible to perform optimal distortion correction according to the usage mode of the user by prohibiting the process of correcting the distortion of the image data according to the JOB mode.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. However, the scope of the invention is not limited to the illustrated examples.

First, the configuration of the present embodiment will be described.
FIG. 1 is a block diagram showing a functional configuration of an image forming apparatus 1 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 includes a control unit 11, an operation display unit 12, an image processing unit 13, a reading unit 14, a writing unit 15, an engine control unit 16, a driving unit 17, a sensor unit 18, and the like. It is configured. Note that the writing unit 15, the engine control unit 16, the drive unit 17, and the sensor unit 18 are collectively referred to as an image forming unit 19.

  As shown in FIG. 2, the control unit 11 includes a CPU (Central Processing Unit) 11a, a ROM (Read Only Memory) 11b, a RAM (Random Access Memory) 11c, an I / O 11d, a nonvolatile memory 11e, and the like. The CPU 11a expands various control programs stored in the ROM 11b in the storage area of the RAM 11c, and performs various processes such as control of the entire image forming apparatus 1 and instructions to the respective units based on the programs. For example, the CPU 11a reads a registration processing program, an adjustment data setting processing program, and an image formation processing program from the ROM 11b, and registers (see FIG. 5), adjustment data setting processing (see FIG. 6), and image formation processing (see FIG. 6). 7). Details of each process will be described later.

  The I / O 11d is an interface that inputs and outputs data between the CPU 11a and the operation display unit 12, the image processing unit 13, the reading unit 14, the writing unit 15, and the like. The nonvolatile memory 11e is composed of an electrically rewritable EEPROM (Electrically Erasable Programmable Read Only Memory) or HDD (Hard Disc Drive), and stores various processing programs and data processed by the processing programs. Specifically, the nonvolatile memory 11e stores an adjustment file 11f that stores inclination amounts (hereinafter referred to as “adjustment data”) in the main scanning direction and the sub-scanning direction registered in a registration process described later.

  The adjustment file 11f stored in the nonvolatile memory 11e will be described with reference to FIG. FIG. 4 is a diagram illustrating a data configuration example of the adjustment file 11f. As shown in FIG. 3, the adjustment file 11 f includes a registration name, a paper type 1 (material), a paper type 2 (basis weight), a setting condition including a paper type 3 (brand), and main scanning inclination (front / back). , And records 11g to 11l for storing adjustment data including sub-scanning inclination (front / back).

First, the records 11g to 11j in which setting conditions are stored will be described.
In the registration name record 11g, text data of the registration name input from the user on the adjustment data setting screen described later is stored as, for example, “file 1 (PPC)”. In the record 11h of the paper type 1 (material), data indicating the material among the indexes indicating the characteristics of the paper type is stored as, for example, “PPC paper vertical grain”. In the record 11i of paper type 2 (basis weight), numerical data of basis weight indicating the weight per area of the transfer paper is stored as, for example, “˜60 g / m 2”. In the record 11j of the paper type 3 (brand), text data indicating the brand (name) of the transfer paper is stored as, for example, “XX paper”.

Next, the records 11f to 11l in which adjustment data is stored will be described. The adjustment data is stored in association with the front side / back side of the transfer paper, the upper level is data corresponding to the front side, and the lower level is data corresponding to the back side.
In the main scanning tilt record 11k, adjustment data for setting the tilt amount in the main scanning direction according to the front / back surface of the transfer sheet is stored as, for example, “0.1%, −0.1%”. Yes. In the sub-scanning tilt record 11l, adjustment data for setting the tilt amount in the sub-scanning direction according to the front / back surface of the transfer sheet is stored as “0.1%, 0.2%”.

  Note that the paper types 1 to 3 stored in the adjustment file 11f are merely examples, and other indexes indicating characteristics of various paper types (for example, size, manufacturing method, gap direction, surface roughness, etc.) are stored. It may be a configuration. Further, a configuration may be adopted in which a tray is stored in the adjustment file 11f, or a configuration in which adjustment data can be acquired based on a tray selected at the time of image formation. Or the structure by which adjustment data is acquired according to the combination of a registration name, a tray, and the paper types 1-3 may be sufficient.

  Further, the adjustment file 11f may store adjustment data in association with the JOB mode. For example, the configuration may be such that adjustment data for the front / rear side is stored in association with the JOB mode for performing duplex printing, and adjustment data for only one side is stored for the other JOB modes. Thereby, adjustment data is acquired from the adjustment file 11f according to the selected JOB mode, and image formation according to the JOB mode can be performed. Further, it is preferable that the job mode for executing the aggregation function is set to prohibit the distortion correction processing using the adjustment data.

  The control unit 11 controls the image processing unit 13 to cause the image data to execute independent rotation processing in the main scanning direction and the sub-scanning direction based on the adjustment data stored in the adjustment file 11f described above. That is, as shown in FIG. 5A, the image data is subjected to distortion correction processing based on the return amount of the transfer paper that has been distorted and contracted by the fixing roller, as shown in FIG. It is possible to prevent image data from being distorted when the post-transfer sheet is restored.

  The operation display unit 12 is configured by an LCD (Liquid Crystal Display), and displays various operation buttons, device status display, operation status of each function, and the like on the display screen according to instructions of a display signal input from the control unit 11. Do. The LCD display screen is covered with a pressure-sensitive (resistive film pressure) touch panel configured with transparent electrodes arranged in a grid, and the XY coordinates of the force point pressed with a finger or a touch pen are expressed as voltage values. The detected position signal is output to the control unit 11 as an operation signal. The operation display unit 12 includes various operation buttons such as a numeric button and a start button, and outputs an operation signal generated by the button operation to the control unit 11. In the operation display unit 12, the operation unit and the display unit may be configured as separate bodies.

  The image processing unit 13 performs predetermined image processing on an image signal obtained by reading by the reading unit 14 in accordance with an instruction from the control unit 11. The image processing unit 13 will be described in detail with reference to FIG. FIG. 3 is a block diagram illustrating a main configuration of the image processing unit 13. As shown in FIG. 3, the image processing unit 13 includes an A / D conversion unit 13a, a luminance density conversion unit 13b, a rotation processing / error diffusion processing unit 13c, a compression unit 13d, an image memory 13e, an expansion unit 13f, and the like. Composed.

  The A / D conversion unit 13a converts the analog image signal input from the reading unit 14 into a digital image signal, and outputs the digital image signal to the luminance density conversion unit 13b. The luminance density conversion unit 13b performs luminance conversion processing and density conversion processing on the input image signal, and outputs image data to the rotation processing / error diffusion processing unit 13c.

  The rotation processing / error diffusion processing unit 13c corrects image distortion by performing rotation processing and error diffusion processing on the input image data. Specifically, the rotation processing / error diffusion processing unit 13b performs error diffusion processing on the YMCK image signal, and outputs an image signal having the number of gradations and resolution according to the performance of the writing unit 14. Is generated. Further, under the control of the control unit 11, a rotation process for correcting image distortion is performed on the image signal based on the tilt amount (adjustment data) with respect to the main scanning direction and the sub-scanning direction. This rotation process is performed independently in each of the main scanning direction and the sub-scanning direction, and accordingly, uneven distortion in the main scanning direction and the sub-scanning direction can be corrected appropriately.

  The compression processing unit 13d compresses the image signal input from the rotation processing / error diffusion processing unit 13c and outputs the compressed image signal to the image memory 13e. The image memory 13e is configured by a nonvolatile memory or the like, and stores the image signal compressed by the compression processing unit 13d in a predetermined area. Further, under the control of the control unit 11, the compressed image signal is read and output to the decompression processing unit 13f. The decompression processing unit 13 decompresses the compressed image signal and outputs it to the writing unit 15.

  Returning to FIG. 1, the reading unit 14 includes a light source, a mirror group, a lens, a CCD (Charge Coupled Device), and the like. The reading unit 14 reflects light scanned from the light source to the document according to the control of the control unit 11 by a mirror group, forms an image of the reflected light by a lens, photoelectrically converts it by the CCD, and reads and reads the document image. The image data is output to the image processing unit 13.

  The writing unit 15 includes an LD (Laser Diode), a photosensitive drum, a plurality of trays that store transfer paper for each of a plurality of paper types, a paper discharge unit that discharges the transfer paper after image formation, and the like. The writing unit 15 drives and controls the LD based on the image signal to form an electrostatic latent image on the surface of the photosensitive drum. Further, the toner is attached to the area including the electrostatic latent image on the surface of the photosensitive drum, and the toner is transferred and fixed onto the transfer paper conveyed from the paper feeding unit, and then discharged from the discharge unit.

  The engine control unit 16 controls each drive unit 17 based on data input from the sensor unit 18 in accordance with the control of the control unit 11. The drive unit 17 includes a motor or the like, and is driven according to the control of the engine control unit 16. The sensor unit 18 includes, for example, a temperature sensor, a bypass sensor, a passage detection sensor, a paper discharge sensor, and the like, and outputs a detection signal to the engine control unit 16.

Next, the operation of the present embodiment will be described.
As a premise for explaining the operation, a program for realizing each process described in the following flowchart is stored in the ROM 11b in the form of a program code readable by the CPU 11a of the image forming apparatus 1, and the CPU 11a Then, the operation according to the program code is sequentially executed.

  A registration process for registering adjustment data in the adjustment file 11f will be described with reference to FIG. FIG. 6 is a flowchart showing a registration process executed by the CPU 11a of the image forming apparatus 1. As shown in FIG. 6, the CPU 11a determines whether or not an adjustment data setting instruction is input from the user via the operation display unit 12 (step S1), and when the adjustment data setting instruction is input (step S1). Step S1; YES), an adjustment mode is set, and an adjustment data setting screen (see FIG. 9) is displayed on the operation display unit 12 (Step S2). Here, the adjustment data setting screen will be described with reference to FIG.

  FIG. 9 is a diagram illustrating an example of the adjustment data setting screen 121. As shown in FIG. 9, on the adjustment screen 121, an item 121a for inputting a registered name, an area 121b for inputting front adjustment data, an area 121c for inputting rear adjustment data, and a confirmation button 121d for inputting a confirmation instruction. A registration button 121e for inputting a registration instruction is provided. The area 121b includes an area 121f for displaying main scanning inclination adjustment data, a button 121g for inputting main scanning inclination adjustment data, an area 121h for displaying sub-scanning inclination adjustment data, and sub-scanning inclination adjustment data. An input button 121i is provided.

  When the buttons 121g and 121i provided in the area 121b are instructed on the adjustment setting screen 121, the adjustment data on the surface of the transfer paper is input, and the adjustment data is displayed in the corresponding display areas 121f and 121h. Similarly to the area 121b, the area 121c is also provided with a display area and an input button for each adjustment data. When the corresponding button is instructed, each adjustment data on the back surface of the transfer sheet is input and the corresponding data is input. The set value is displayed in the display area. When the confirmation button 121d is instructed, a setting condition input screen described later is displayed. Further, when the registration button 121e is instructed, each input adjustment data is stored in the adjustment file 11f and registered.

  Returning to FIG. 6, the CPU 11a executes an adjustment data setting process for setting adjustment data on the adjustment data setting screen 121 displayed on the operation display unit 12 (step S3). The adjustment data setting process will be described with reference to FIG. FIG. 7 is a flowchart showing the adjustment data setting process executed as part of the registration process.

  As shown in FIG. 7, when an item for inputting a registered name is selected on the adjustment data setting screen 121 described above (step S11; YES), the CPU 11a inputs the registered name (step S12). Next, when the surface is selected (step S13; YES) and the main scanning tilt item is selected (step S14; YES), the main scanning tilt adjustment data is input (step S15). When selected (step S16; YES), adjustment data for sub-scanning tilt is input (step S17).

  Subsequently, when the back side is selected (step S18; YES), the above-described processing of steps S14 to S17 is repeatedly executed to input adjustment data for the main scanning tilt and the sub-scanning tilt of the back side. Subsequently, in the adjustment data setting screen 121, it is determined whether or not the confirm button has been instructed (step S19). When the confirm button has been instructed (step S19; YES), the setting condition input screen (see FIG. 10) is displayed. It is displayed (step S20). Here, the setting condition input screen will be described with reference to FIG.

  FIG. 10 is a diagram illustrating an example of the setting condition input screen 122. As shown in FIG. 10, the setting condition input screen 122 includes an area 122a for displaying a registered name, an item 122b for selecting a material, an item 122c for selecting a basis weight, an item 122d for selecting a brand (name), and a confirmation item. A button 122e for inputting an instruction is provided.

  In the area 122a, the name registered on the adjustment data input screen 121 is displayed. In the item 122b, a list of material types is displayed as an index indicating the characteristics of the first paper type. In the item 122c, the basis weights divided into predetermined ranges are displayed as a list as an index indicating the characteristics of the second paper type. The item 122d displays a list of brands of transfer paper as an index indicating the characteristics of the third paper type. In each of the items 122b to 122d, the material, the basis weight, and the brand are selected, and when the confirm button 122e is pressed, the setting condition is confirmed.

  Returning to FIG. 7, when the setting condition is input on the setting condition input screen 122 displayed on the operation display unit 12, the CPU 11a acquires the input setting condition (step S21). Then, it is determined whether or not the confirm button has been instructed on the setting condition input screen 122 (step S22). If the confirm button has been instructed (step S22; YES), the setting condition input screen 122 is closed and adjustment data setting is performed. Returning to the screen 121, it is determined whether or not the registration button 121e is instructed on the adjustment data setting screen 121 (step S23). When the registration button is instructed (step S23; YES), the adjustment data setting process is terminated and the process proceeds to a registration process.

  Subsequently, returning to FIG. 6, when the CPU 11a is instructed to end the setting of the adjustment data (step S4; YES), the CPU 11a stores the adjustment data and the setting condition in a predetermined record of the adjustment file 11f (step S5). . Next, it is determined whether or not the registration is to be ended (step S6). When an instruction to continue the registration is input (step S6; NO), the process proceeds to step S2 and the above-described processing is repeatedly executed. . On the other hand, when an instruction to end registration is input (step S6; YES), the main registration process is ended. In step S4, if the adjustment data setting process is not properly terminated and an error or the like occurs (step S4; NO), the registration is performed without rewriting the adjustment file 11f with the data set in the adjustment data setting process. The process ends.

  Next, with reference to FIG. 8, an image forming process for performing image processing on image data based on the adjustment data stored in the adjustment file to form an image will be described. FIG. 8 is a flowchart showing an image forming process executed by the CPU 11a. As shown in FIG. 8, when an image formation instruction is input by the user via the operation display unit 12 (step S31; YES), the CPU 11a determines whether or not the aggregation function is set as the JOB mode. (Step S32). Here, the aggregation function refers to, for example, a function of reducing image data for one page and printing image data for a plurality of pages on one side of a transfer sheet.

  When the aggregation function is not set (step S32; NO), the CPU 11a determines whether or not it is the front side document of the transfer paper (step S33). If it is the front side document (step S33; YES), the adjustment file The surface adjustment data is acquired from 11f (step S34). On the other hand, if it is a back side original of transfer paper (step S33; NO), the CPU 11a acquires back side adjustment data from the adjustment file 11f (step S35).

  Next, the CPU 11a acquires the image data read from the reading unit 14 (step S36), and controls the image processing unit 13 to perform image processing for correcting image distortion based on the adjustment data (step S37). Subsequently, the CPU 11a controls the writing unit 15 to form an image on the transfer paper (step S38), and determines whether there is image data to be imaged next (step S39). If there is next image data (step S39; YES), the CPU 11a proceeds to step S32 and repeats the above-described processing. On the other hand, when there is no next image data (step S39; NO), the CPU 11a ends the image forming process.

  If the aggregation function has been set in step S32 (step S32; YES), the CPU 11a reads the image data without acquiring the adjustment data (step S36). Next, the CPU 11a prohibits the process of correcting the image distortion, performs normal image processing on the image data (step S37), and causes the writing unit 15 to perform image formation based on the image data (step S38).

  As described above, according to the image forming apparatus 1 of the present embodiment, the adjustment data for the main scanning tilt and the sub-scanning tilt is displayed on the operation display unit according to the indexes indicating the characteristics of the front / back surface of the transfer paper and the paper type. 12 and input adjustment data is set in the adjustment file 11f. When image formation is performed, adjustment data is acquired from the adjustment file 11f in accordance with the front / back surface of the transfer paper and the paper type, and image data is subjected to rotation processing based on the adjustment data to correct image distortion. And image formation is performed on the transfer paper.

  Therefore, when the distortion or shrinkage rate of the transfer paper is different, the main scanning direction and the sub-scanning direction of the image data based on the adjustment data set according to the index indicating the characteristics of the front / back surface of the transfer paper and the paper type Since the image distortion can be corrected independently, the positional accuracy of the image data formed on the front / back surface of the transfer paper can be improved.

  Further, since it is possible to independently correct the distortion for the front surface / back surface, for example, for the front surface, the distortion of the read image due to an optical lamp mounting error or the like in the reading unit 14 is corrected, and for the back surface, the read image is corrected. And distortion due to shrinkage of the transfer paper can be corrected.

  Further, since the image distortion on the back surface needs to be corrected according to the paper type of the transfer paper, various paper types are stored by storing the adjustment data in the adjustment file 11f according to the index indicating the characteristics of the paper type. The optimum distortion correction can be performed according to the above.

  For example, adjustment data can be set according to an index (for example, material, basis weight, brand, manufacturing method, size, gap direction, surface roughness, etc.) indicating characteristics of a plurality of paper types. Adjustment data can be set according to the properties of the transfer paper. As a result, it is possible to accurately correct misalignment due to a difference in the shrinkage rate of the transfer paper caused by a slight difference in paper type.

  Further, the adjustment data set by the user is stored in a plurality of adjustment files 11f, and optimal adjustment data is appropriately acquired based on the index indicating the front / back surface of the transfer paper and the paper type, and image formation is performed. Therefore, it is not necessary to set adjustment data for each image formation, and image formation can be easily performed based on optimum adjustment data.

  Further, when the aggregation function is set as the JOB mode, a plurality of read images may be formed on one side, so that distortion correction based on the adjustment data is prohibited, so that it can be used according to the usage mode of the user. Optimal correction.

  Note that the description in the present embodiment described above is an example of a suitable image forming apparatus according to the present invention, and the present invention is not limited to this. For example, the type of the paper type in the present embodiment is not limited to the above-described example, and may include an OHP sheet, tracing paper, a film, and the like. In addition, the detailed configuration and detailed operation of the components of the image forming apparatus 1 in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

1 is a block diagram illustrating a functional configuration of an image forming apparatus according to an embodiment to which the present invention is applied. It is a block diagram which shows the principal part structure of the control part 11 shown in FIG. It is a block diagram which shows the principal part structure of the image process part 13 shown in FIG. It is a figure which shows the data structural example of the adjustment file 11f shown in FIG. It is a figure explaining the correction method of the image distortion of a back surface. It is a flowchart which shows the registration process performed by CPU11 shown in FIG. It is a flowchart which shows the adjustment data setting process performed as a part of registration process shown in FIG. It is a flowchart which shows the image formation process performed by CPU11 shown in FIG. It is a figure which shows an example of the adjustment data setting screen 121 displayed on the operation display part 12. FIG. 6 is a diagram showing an example of a setting condition input screen 122 displayed on the operation display unit 12. FIG.

Explanation of symbols

1 Image forming apparatus 11 Control unit 11a CPU
11b ROM
11c RAM
11d I / O
11e Non-volatile memory 11f Adjustment file 12 Operation display unit 13 Image processing unit 13a A / D conversion unit 13b Luminance density conversion unit 13c Rotation processing / error diffusion processing unit 13d Compression unit 13e Image memory 13f Expansion unit 14 Reading unit 15 Writing unit 16 Engine control unit 17 Drive unit 18 Sensor unit 19 Image forming unit

Claims (5)

An image forming apparatus including an image forming unit that forms images on both sides of transfer paper based on image data,
An image processing unit that performs processing for correcting distortion of the image data by changing the amount of inclination of the image data in the main scanning direction and the sub-scanning direction;
A control unit that sets the amount of inclination in the main scanning direction and the sub-scanning direction according to the front and back surfaces of the transfer paper, and causes the image processing unit to perform processing for correcting distortion of image data;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the control unit sets an inclination amount in a main scanning direction and a sub-scanning direction independently for a front surface and a back surface of the transfer sheet.   The image forming apparatus according to claim 1, wherein the control unit sets an inclination amount in the main scanning direction and the sub-scanning direction according to an index indicating a characteristic of a paper type of the transfer paper.   The index indicating the characteristics of the paper type is an index indicating the characteristics of the paper type including at least one of the material, basis weight, manufacturing method, brand, size, gap direction, and surface roughness of the transfer paper, or a combination thereof. The image forming apparatus according to claim 3, wherein the image forming apparatus is an index indicating characteristics of a paper type.   5. The image forming apparatus according to claim 1, wherein the control unit prohibits the image processing unit from correcting a distortion of image data in accordance with a JOB mode.

Images