JP2009258662A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To print an image that improves a reading rate by a barcode reader or the like for a barcode and a QR code (R) or the like even in an image forming apparatus equipped with a skew correction function by image processing. <P>SOLUTION: When a specified image exists in a page S102, an image printing part receives information on a main scanning start position of the specified image and main scanning width of the specified image from an image generation part S103 and S104. Furthermore, a joint position of a skew correction area set in advance is confirmed S105, and whether the main scanning area (from main scanning start position to main scanning finish position) of the specified image BC and a joint are superposed each other is checked S106. When they are superposed each other, since it is necessary to correct width of the skew correction area, the width of the skew correction area is compared with the main scanning width of the specified image, and the joint position is shifted left or right according to a result of comparison, so as to newly set the joint at a position where they are not superposed each other S108, S109. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an image forming apparatus capable of printing a specific image such as a barcode, and more particularly to an image forming apparatus capable of automatically correcting and printing the deviation of the specific image.

In an electrophotographic image forming apparatus, when barcode printing is performed, even when the toner density is set to an arbitrary value, the reading rate of the barcode printed with the toner density by the barcode reader is the highest. As described above, a configuration for automatically changing the bar width of the barcode and printing the barcode is already known. For example, there is an invention described in Patent Document 1.

The present invention relates to a setting unit that stores one piece of information selected from several pieces of information indicating toner density, and a printing mechanism that performs printing on a sheet with the toner concentration indicated by the information stored in the setting unit. , For each of all the toner densities that can be set in the setting section, information for defining the toner density and a reference bar for a bar width at which the reading rate by the barcode reader for a barcode printed at the toner density is optimum A storage unit that associates and stores an increment amount from a width, a receiving unit for receiving a print request from a host computer via communication means, and the receiving unit receives the print request from the host computer; If the print request does not indicate barcode printing, print the document image based on the print data in the print request. If the print mechanism is to make a print request to instruct barcode printing, the bar width increment corresponding to the toner density set in the setting unit is read from the storage unit, Change the parameters of the commands that make up the print data in the received print request so that the bar width of the code is increased by that increment,
The present invention is characterized by a printing apparatus including a print control unit that causes the printing mechanism to print a barcode image based on the changed print data. That is, according to the present invention, when performing barcode printing, it is not necessary to perform an operation for changing the bar width or an operation for returning the toner density to the standard value even when the toner density is set to an arbitrary value. Therefore, even if the toner density is arbitrarily set, the barcode width is automatically set so that the barcode reader with the highest barcode reading rate can be printed. It is changed and barcode printing is performed.

On the other hand, in an electrophotographic color image forming apparatus, color misregistration correction is performed. At this time, a main scanning direction which is a width direction orthogonal to the transfer belt transfer direction and a sub-scan which is the same direction as the transfer belt transfer direction. As for the color misregistration in the oblique direction (inclination direction) that is between the direction and the direction, for example, based on the registration mark position information obtained by the mark detection means, for example, each line of the image data captured from the image memory into the line buffer There is already known a configuration in which the read address is corrected for each color at a predetermined position in the main scanning direction (hereinafter referred to as skew correction by image processing).

However, when changing the bar width at the time of barcode printing up to now and using it at the same time as skew correction by image processing, the joint of the skew correction area may overlap with the printed portion of the barcode, resulting in a step in the middle of the barcode There is a problem that when such a step occurs, the reading rate of the barcode reader deteriorates.

Therefore, the problem to be solved by the present invention is to print an image that improves the reading rate of a barcode reader such as a barcode or QR code even in an image forming apparatus having a skew correction function by image processing. Is to be able to do that.

In order to solve the above problem, the first means includes a skew correction means, and in the image forming apparatus for forming an image on the recording medium, obtains a start position and an end position of the specific image formed on the recording medium. Position information obtaining means, a skew correction area width designated in advance, a readout means for reading a joint position of the skew correction area based on the skew correction area width, a main scanning width of the specific image, and the skew correction area First comparison means for comparing whether or not the seam positions overlap, second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger, and the main comparison From the scanning width and the skew correction area seam position, a new scan is performed so that the specific image and the skew correction area seam position do not overlap. And resetting means for setting the over correction area connection position, characterized by comprising a.

The second means includes a skew correction means, and in an image forming apparatus for forming an image on a recording medium, position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium; Readout means for reading out the skew correction area width specified in advance and the joint position of the skew correction area based on the skew correction area width, whether the main scanning width of the specific image and the joint position of the skew correction area overlap Skew correction in a region excluding the specific image, a first comparison unit that compares the main scanning width of the specific image, and a second comparison unit that compares which of the skew correction area width is larger. Resetting means for resetting the area width and the skew correction area seam position.

The third means includes skew correction means, and in the image forming apparatus for forming an image on the recording medium, position information acquisition means for acquiring a start position and an end position of the specific image formed on the recording medium; Readout means for reading out the skew correction area width specified in advance and the joint position of the skew correction area based on the skew correction area width, whether the main scanning width of the specific image and the joint position of the skew correction area overlap First comparison means for comparing, a second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger, and a skew at a joint position overlapping the specific image And a seam position moving means for moving the correction amount to a position excluding the specific image main scanning position.

The fourth means includes a skew correction means, and in an image forming apparatus for forming an image on a recording medium, position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium; Readout means for reading out the skew correction area width specified in advance and the joint position of the skew correction area based on the skew correction area width, whether the main scanning width of the specific image and the joint position of the skew correction area overlap A first comparison means for comparing, a second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger, and the identification recognized by the first comparison means And a resetting means for resetting the skew correction amount at a position where the image and the seam overlap.

  A fifth means is characterized in that, in the fourth means, the cue correction amount is zero.

A sixth means is characterized in that, in any of the first to fourth means, the specific image is a barcode.

A seventh means is characterized in that, in any one of the first to fourth means, the specific image is a QR code.

The eighth means is characterized in that, in any one of the first to fourth means, the specific image is an image read by the reading means for other processing after printing.

According to a ninth means, in any one of the first to fourth means, when the first comparison means finds that the specific image and the skew correction area joint position overlap, the joint position overlaps. This is characterized in that no skew correction is performed on the page.

In the embodiment described later, the skew correction means is assigned to the ASIC 24 and the specific image is assigned to the code BC.
In addition, the position information acquisition means is the CPU 21 that acquires the specific image position information from the image generation unit 1, and the reading means that reads the joint position of the skew correction area is the ASIC 24, the first and second
The comparison means includes, in the comparison function 31 of the CPU function 3, resetting means for setting the seam position, seam position moving means, and resetting means for resetting the skew correction amount at the position where the seam overlaps the skew correction area of the CPU function 3. In the width resetting function 32 and the skew correction start position determining function 33,
Each corresponds.

According to the present invention, the skew correction area position is corrected so that the joint position between the specific image and the skew correction area does not overlap. Therefore, even in an image forming apparatus having a skew correction function by image processing, a barcode or QR code is used. It is possible to print an image that improves the reading rate of a bar code reader or the like such as a code.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the outline of the mechanical structure of the image forming apparatus implemented conventionally and implemented also by this invention. FIG. 3 is a perspective view of a transfer belt and a photosensitive drum showing a state in which a correction pattern for correcting misregistration is formed on the transfer belt. It is a figure which shows an example when detecting a position shift correction pattern with two detection sensors. It is explanatory drawing which shows one method of a skew correction method (skew correction amount calculation method). It is a figure which shows the state of the joint position of the specific image which concerns on embodiment of this invention. It is a flowchart which shows the process sequence in the CPU function which concerns on this embodiment. It is a figure which shows the state of specific image BC correct | amended by the process sequence of FIG. It is a figure which shows an example of the process of step S112 of FIG. It is a figure which shows the other example of a process of step S112 of FIG. It is a figure which shows the further another example of the process of step S112 of FIG. It is a figure which shows the other example of skew correction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 1A is a block diagram illustrating a printing configuration of the image forming apparatus, and FIG. 1B is a block diagram illustrating a CPU function. .

The image forming apparatus includes an image generation unit 1 and an image printing unit 2. The image generation unit 1 transmits coordinate information of a specific image such as image data to be printed and a barcode to the image printing unit 2. The image printing unit 2 performs various arithmetic processes based on the information transmitted from the image generation unit 1.
A memory 22 for temporarily storing data, an engine 23 for printing and outputting images,
And an ASIC 24 that performs skew correction by various image processing and image processing.

The CPU function 3 mainly includes a comparison function 31 that compares whether the main scanning area of the specific image and the joint of the skew correction area overlap, and a function 32 that resets the skew correction area width if there is an overlap. And a function 33 for resetting the skew correction start position from the reset skew correction area width. The CPU 21 reads a program stored in a ROM (not shown), executes processing according to the program while using a memory (RAM) 22 as a work area, and performs desired control.

FIG. 2 is a diagram showing an outline of the image forming unit of the image forming apparatus according to the embodiment of the present invention, and this configuration itself is a known configuration that has been conventionally implemented.

  The image forming apparatus shown in FIG. 2 is an example of a so-called direct transfer tandem image forming apparatus.

In FIG. 1, the image forming apparatus basically includes an image forming process unit 1, an optical writing unit (exposure unit) 9, and a paper feeding unit (paper feeding tray) 6. The image forming process unit 1 is configured such that each station that forms an image of a different color (yellow: Y, magenta: M, cyan: C, black: K) is applied to a transfer belt 3 that conveys a transfer sheet 2 as a transfer medium. It is arranged in a line along.

The transfer belt 3 is stretched between a drive roller 4 that is driven to rotate and a driven roller 5 that is driven to rotate, and is driven to rotate in the direction of the arrow in FIG. Under the transfer belt 3, a paper feed tray 6 containing the transfer paper 2 is provided, and functions as a paper feed unit.

The transfer sheet 2 at the uppermost position among the transfer sheets 2 stored in the sheet feed tray 6 is fed toward the transfer belt 3 at the time of image formation.

The transfer sheet 2 conveyed to the transfer unit is conveyed to the first image forming station 1Y (yellow), where yellow image formation is performed. The first image forming station 1Y includes a photoreceptor drum 7Y, a charger 8Y, a developer 10Y, and a photoreceptor cleaner 11Y arranged around the photoreceptor drum 7Y. The charger 8Y and the developer 10Y In the meantime, an exposure unit to which the laser beam LY is irradiated from the exposure unit 9 is provided.

The surface of the photosensitive drum 7Y is uniformly charged by the charger 8Y, and then exposed by the exposure device 9 with the laser light LY corresponding to the yellow image, thereby forming an electrostatic latent image. The formed electrostatic latent image is developed by the developing device 10Y, and a toner image is formed on the photosensitive drum 7Y. This toner image is a position (transfer position) where the photosensitive drum 7Y and the transfer paper 2 on the transfer belt 3 are in contact with each other.
The image is transferred onto the transfer paper 2 by the transfer device 12Y, whereby a single color (yellow) image is formed on the transfer paper 2. In the photoreceptor drum 7Y after the transfer, unnecessary toner remaining on the drum surface is cleaned by the photoreceptor cleaner 11Y to prepare for the next image formation.

As described above, the transfer paper 2 on which the single color (yellow) is transferred by the first image forming station 1Y (yellow) is conveyed by the transfer belt 3 to the second image forming station 1M (magenta). Similarly, the toner image (magenta) formed on the photosensitive drum 7M is transferred onto the transfer paper 2 in a similar manner. The transfer paper 2 further includes a third image forming station 1C (cyan).
And the fourth image forming station 1K (black) in order, and similarly, the formed toner images are sequentially superimposed on the transfer paper 2, whereby a color image is formed on the transfer paper 2. The second, third, and fourth image forming stations 1M, 1C, and 1K (magenta, cyan, and black) have the same configuration as that of the first image forming station 1Y (yellow). The description is omitted after clarifying that the image forming station is for each color.

  The transfer paper 2 on which the color images are superimposed by the first to fourth image forming stations 1Y, 1M, 1C, and 1K to form a full-color image is peeled off from the transfer belt 3 and fixed by the fixing device 13. Are discharged.

FIG. 3 is a perspective view of the transfer belt 3 and the photosensitive drums 7Y, 7M, 7C, and 7K showing a state in which a correction pattern 14 for correcting misregistration is formed on the transfer belt 3. In the tandem type color image forming apparatus shown in FIG. 1, an alignment technique between colors becomes an important issue because of its configuration. Therefore, in the color image forming apparatus according to the present embodiment, the positional deviation correction of each color is performed before the actual color image forming operation is performed on the transfer paper 2.

For this purpose, first, a correction pattern 14 for correcting misregistration of each color is formed on the transfer belt 3, and this is detected by a plurality of detection sensors. In the present embodiment, two detection sensors 1
5 and 16 are arranged at both ends of the transfer belt 3 in the main scanning direction, and the correction pattern 14 is formed on the transfer belt 3 in correspondence with the arrangement positions of the detection sensors 15 and 16. The correction pattern 14 is detected when the transfer belt 3 rotates and moves and sequentially passes through the detection sensors 15 and 16. When the correction pattern 14 is detected, various deviation amounts and correction amounts are calculated from the detection results, and each deviation component is corrected.

FIG. 4 is a diagram showing an example when the position deviation correction pattern is detected by the two detection sensors 15 and 16. The correction pattern 14 is detected by the detection sensors 15 and 16, and the obtained signal is converted from analog data to digital data by the pattern detection unit, the data is sampled, and the sampled data is stored in the RAM. Complete correction pattern 1
4 is completed, the ASIC 24 performs arithmetic processing for calculating various color misregistration amounts (main scanning magnification, main scanning registration, sub-scanning registration, skew) for the data stored in the memory 22, and the color A correction amount of each shift component is calculated from the shift amount. The ASIC 24 performs skew correction based on the correction amount.

For skew correction, first, the skew amount of each color with respect to the K color is obtained. For example, when the right side of the C color image is shifted downward as shown in the lower diagram of FIG. 4, the skew amount of the C color: KC_
Skew
KC_Skew = KC_R−KC_L (1)
It is obtained like this.

FIG. 5 is an explanatory diagram showing a skew correction method (a skew correction amount calculation method). FIG.
In the case where the input image FIG. 5A is output as LD data as it is due to the skew of the scanning beam, the right side of the transfer paper 2 on the right side of the input image FIG. (The number of skew lines is 3). When the right side image is shifted upward by 3 lines as shown in FIG. 5B, the main scanning is performed by the number of lines of the skew amount as shown in FIG.
1 is divided into four equal parts, and an image shifted downward by one line each time it goes to the right as shown in FIG. 5D, each image is transferred onto the transfer paper 2 as shown in FIG. The image positions on the left and right of the line are parallel.

FIG. 6 is a diagram showing the state of the joint position of the specific image according to the embodiment of the present invention. That is, here, a new skew correction area seam position is set from the main scanning width N of the specific image BC and the skew correction area seam position so that the specific image BC and the skew correction area seam position do not overlap. Like to do. FIG. 6A shows a case where the main scanning area of the specific image BC and the joint T of the skew correction area overlap when skew correction is performed by conventional image processing. In this case, a step D occurs in the specific image BC, and the reading rate with a reader or the like deteriorates. In this case, the specific image BC is re-set in the main scanning region of the specific image BC so that the joint T of the skew correction area does not overlap, and the skew correction is performed again, so that the specific image BC as shown in FIG. An image with a high reading rate that does not cause a step can be printed.

Here, the specific image BC refers to an image that needs to be read by a reader or the like after printing, such as a barcode or a QR code (hereinafter the same).

FIG. 7 is a flowchart showing a processing procedure in the CPU function 3 according to the present embodiment, and FIG. 8 is a diagram showing a state of the specific image BC corrected by the processing procedure of FIG.

First, when a print start instruction is received from the image generation unit 1 (step S100), for example, a skew correction parameter is set based on the skew amount obtained by the ASIC 24 based on the equation (1) (step S101). Thereafter, the image printing unit 2 receives from the image generation unit 1 whether the specific image BC exists in the page P together with the image data (step S102).
. If it is found that there is no specific image BC (No in step S102), the parameter setting is terminated without changing the preset parameter.

If there is a specific image BC in the page P (step S102—Yes), the specific image B
The image printing unit 2 receives information on the main scanning start position M of C and the main scanning width N of the specific image BC from the image generation unit 1 (steps S103 and S104). Further, the joint position of the preset skew correction area is confirmed (step S105), and it is checked whether or not the joint overlaps with the main scanning region (from the main scanning start position to the end position) of the specific image BC (step S106). ).

As a simple confirmation method, the skew correction start position (position where the first correction area starts) is A, n is an integer, the skew correction area width is Z, and the joint position Zn is
Zn = A + Z × n (2)
Is expressed as
M <Zn <M + N (3)
It is confirmed whether or not n satisfying the above condition exists. If such n does not exist (step S106-No), since the step D does not occur in the specific image BC even if the setting is maintained, the parameter setting is performed without changing the preset parameter. Exit.

If n satisfying equation (3) is present (step S106—Yes), it is necessary to correct the skew correction area width. In this case, the skew correction area width Z and the main scanning width N of the specific image are compared,
Z ≧ N
If so (step S107—Yes), the joint position T is shifted to the left or right, and a new joint T ′ is set where it does not overlap (step S108). At this time, the shift direction may be left or right and any direction. However, if the overall correction amount increases after the shift, the correction amount is set to “0” at any one joint in the image area, and the overall correction amount is adjusted before and after the shift. (FIG. 8: point X). The total skew correction seam position is determined based on the shift amount (step S109), the printing is executed (step S110), and the process ends (step S111).

On the other hand, in step S107,
Z <N
In the case of (Step S107-No), the process of Step S112 is executed. Step S
The process 112 is, for example,
(1) Processing for resetting the skew correction area width Z and the skew correction area joint position in the area excluding the specific image BC (see FIG. 9)
(2) Processing for moving the skew correction amount at the joint position overlapping the specific image BC to a position excluding the specific image main scanning position (see FIG. 10).
(3) Processing for resetting the skew correction amount at the position where the specific image BC recognized by the first comparison means and the joint T overlap (see FIG. 11).
Etc.

FIG. 9 shows the process G in step S112 when “Z <N” in step S107, and corresponds to (1) above. Assume that the total skew correction amount is “9”. In the conventional method, since the presence / absence of the specific image BC is not considered, correction areas are provided at equal intervals in the entire image area (FIG. 9A). In the present embodiment, the joint T between the specific image BC and the correction area is provided. Are overlapped (FIG. 9B), the skew correction area is reset in the area excluding the specific image BC (FIG. 9C).

The main scanning width of the entire image area is α, M ′ from the top of the image area to the specific image area, and the specific image B
The main scanning width of C is N ′. Region excluding specific image BC α-N '
Then, the correction area width Z is reset so that the total correction amount “9” can be corrected (FIG. 9B). At the distance M ′ from the front end of the image area to the specific image, the correction area is determined based on the set value Z. When the specific image area is reached, the determination of the correction area is stopped, and correction area information (such as the correction amount at that point and the main scanning width up to the next seam) is retained. When the specific image area ends, the determination of the correction area is resumed (FIG. 9 (c) —arrow Q). This
While maintaining the overall correction amount, it is possible to print an image with a high reading rate that does not cause a step in the specific image BC.

FIG. 10 shows another process G of step S112 when “Z <N” in step S107, and corresponds to (2) above. In FIG. 9, the case where the skew correction area can be freely set has been described, but here is an example in which the skew correction area is determined in advance. In FIG. 10A, it is assumed that the specific image BC overlaps the joint T1, but there is a portion where the correction amount is “0” at one of the other joints T2 that do not overlap. At this time, the correction amount of the joint T1 that overlaps the specific image BC is moved to another joint T3 that does not overlap and has an original correction amount of “0” as shown in FIG. 10B, for example. As a result, it is possible to print an image with a high reading rate without causing a step in the specific image while maintaining the correction amount as a whole.

FIG. 11 shows still another process G in step S112 when “Z <N” in step S107, and corresponds to (3) above. In FIG. 9, the case where the skew correction area can be freely reset has been described. Here, a case where the skew correction area is determined in advance as in the case of FIG. 10 will be described. However, unlike the example of FIG. 10, FIG.
As shown in FIG. 5, it is assumed that the specific image BC overlaps the joint T4, and there is no portion having a correction amount of “0” even in other non-overlapping seams. In this case, if the correction amount is moved to another seam as in the example of FIG. 10, the seam is too conspicuous at the seam to which the correction amount has been added, so the correction amount is not moved and overlaps the specific image. The correction amount at the seam T4 is “0”. As a result, the correction amount as a whole decreases, but skew correction as much as possible is performed, and an image with a high reading rate that does not cause a step in a specific image can be printed.

In the examples (1) to (3) (FIGS. 9 to 11), step S10 in FIG.
6, when the joint between the specific image BC and the skew correction area overlaps, processing is performed so as not to cause a step in the specific image BC while performing skew correction, as shown in FIG. If the joint T5 in the skew correction area and the specific image BC overlap with each other, FIG.
As shown in (b), skew correction is not performed on the entire page P. As a result, it is possible to easily print an image with a high reading rate without causing a step in the specific image BC. Whether or not the specific image BC exists in the page, the position information of the specific image BC is acquired from the previous image generation unit 1.

As described above, according to the present embodiment, information on the start position and main scan width of the bar code in the main scanning direction is obtained, and compared with the joint position of the skew correction area in the current setting, the position where the bar code is present If there is a seam in the skew correction area, the correction area width and seam position are reset so that the bar code position and seam do not overlap. Even if skew correction is performed by image processing, it is possible to provide an image forming apparatus that does not deteriorate the reading rate with a barcode reader and further improves the reading rate.

In addition, this invention is not limited to this embodiment, It cannot be overemphasized that all the technical matters contained in the technical thought described in the claim are included.

DESCRIPTION OF SYMBOLS 1 Image generation part 2 Image printing part 21 CPU
22 Memory 23 Engine 24 ASIC
3 CPU function 31 Comparison function 32 Skew correction area width setting function 33 Skew correction start position determination function BC Specific image T, T1, T2, T3, T4, T5 Seam

JP 2006-256106 A

Claims (9)

In an image forming apparatus having a skew correction unit and forming an image on a recording medium,
Position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium;
Read means for reading the skew correction area width designated in advance and the joint position of the skew correction area based on the skew correction area width;
First comparison means for comparing whether the main scanning width of the specific image and the joint position of the skew correction area overlap;
Second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger;
Resetting means for setting a new skew correction area seam position so that the specific image and the skew correction area seam position do not overlap from the main scanning width of the specific image and the skew correction area seam position;
An image forming apparatus comprising: In an image forming apparatus having a skew correction unit and forming an image on a recording medium,
Position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium;
Read means for reading the skew correction area width designated in advance and the joint position of the skew correction area based on the skew correction area width;
First comparison means for comparing whether the main scanning width of the specific image and the joint position of the skew correction area overlap;
Second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger;
Resetting means for resetting the skew correction area width and the skew correction area joint position in the area excluding the specific image;
An image forming apparatus comprising: In an image forming apparatus having a skew correction unit and forming an image on a recording medium,
Position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium;
Read means for reading the skew correction area width designated in advance and the joint position of the skew correction area based on the skew correction area width;
First comparison means for comparing whether the main scanning width of the specific image and the joint position of the skew correction area overlap;
Second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger;
A joint position moving means for moving the skew correction amount at the joint position overlapping the specific image to a position excluding the specific image main scanning position;
An image forming apparatus comprising: In an image forming apparatus having a skew correction unit and forming an image on a recording medium,
Position information acquisition means for acquiring a start position and an end position of a specific image formed on the recording medium;
Read means for reading the skew correction area width designated in advance and the joint position of the skew correction area based on the skew correction area width;
First comparison means for comparing whether the main scanning width of the specific image and the joint position of the skew correction area overlap;
Second comparison means for comparing which of the main scanning width of the specific image and the skew correction area width is larger;
Resetting means for resetting the skew correction amount at a position where the specific image recognized by the first comparison means and the joint overlap;
An image forming apparatus comprising: The image forming apparatus according to claim 4.
An image forming apparatus, wherein the skew correction amount is zero. 5. The image forming apparatus according to claim 1, wherein:
An image forming apparatus, wherein the specific image is a barcode. 5. The image forming apparatus according to claim 1, wherein:
An image forming apparatus, wherein the specific image is a QR code. 5. The image forming apparatus according to claim 1, wherein:
The image forming apparatus, wherein the specific image is an image read by a reading unit for other processing after printing. 5. The image forming apparatus according to claim 1, wherein:
An image forming apparatus according to claim 1, wherein when the first comparison unit finds that the specific image and the skew correction area joint position overlap each other, skew correction is not performed on a page where the joint position overlaps.

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