JP2005091823A - Method for adjusting image position - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of slippage of image positions on recording paper when both-side printing or the like is performed. <P>SOLUTION: On an image data read out from a sample output 50 obtained by forming a sample image 52 on a sheet of recording paper 30 by a scanner part, one side of the recording paper 30 is extracted and the coordinates (sx<SB>1</SB>, sy<SB>1</SB>), (sx<SB>2</SB>, sy<SB>2</SB>) of points S<SB>1</SB>, S<SB>2</SB>on both the ends of the extracted one-side of the recording paper are found out. A deviation dy along the vertical direction of the recording paper, a deviation dx along the horizontal direction and an inclination α which are reading errors are calculated from the coordinates of the points S<SB>1</SB>, S<SB>2</SB>and these reading errors are excluded by applying image processing so that the point S<SB>1</SB>is superposed to an origin Q for instance. Thus, accurate positional adjustment can be attained by finding out the deviations of image positions between the front and rear surfaces of the recording paper by using the image data from which the reading errors are excluded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image on recording paper by outputting RIP-processed image data to a print output device, and more specifically, an image position adjusting method for forming an image on recording paper About.

  Image output apparatuses that form images on recording paper include laser printers that use an electrophotographic process. In such an image forming apparatus, toner images of C, M, Y, and K colors formed by scanning a laser beam in accordance with image data are transferred to an intermediate transfer member, and the intermediate transfer member is transferred to a recording sheet or the like. By transferring, a color image corresponding to the image data is formed on the recording paper.

  In an image forming apparatus that forms an image on recording paper using such an image output apparatus as a print engine, image data that has undergone RIP processing is output in accordance with the scanning timing of the laser beam in the print engine. An image is formed at a predetermined position.

  Some image forming apparatuses are capable of double-sided printing in which images are formed on both front and back sides of a recording sheet. When performing duplex printing, the recording paper is mechanically reversed in the print engine so that image transfer is performed on both the front and back sides of the recording paper.

  By the way, when double-sided printing is performed, a deviation may occur between the image forming position on the front side and the image forming position on the back side. Further, some print output devices include a plurality of paper feed trays. However, in such a print output device, image formation is performed when recording sheets of the same size are fed from different paper feed trays. Misalignment may occur in the position.

From this point, in a copier capable of duplex printing, a plurality of markers are printed at predetermined positions on the front and back sides of the recording paper, each of the images on the front and back sides is read by a scanner using this printed matter as a document, and the marker of the read image There has been a proposal for obtaining a deviation when performing double-sided printing from the position and adjusting the image position based on the obtained deviation (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-246992

  However, when an original image is read by an image reading unit such as a scanner, a reading error may occur depending on the original mounting position. For this reason, when an image including a marker is printed on a recording sheet and this image is read by the image reading unit, an error at the time of reading is included in the deviation of the image position at the time of printing. Adjustment may be difficult.

  The present invention has been made in view of the above-described facts, and in an image processing apparatus such as a copying machine including an image reading unit in a print output apparatus such as a copying machine, accurately adjusts the position of an image formed on a recording sheet. An object of the present invention is to provide an image position adjusting method capable of

  In order to achieve the above object, the present invention relates to the recording when an image is formed on a recording sheet fed from a sheet feeding unit of a print output apparatus based on image data output from the image processing apparatus to the print output apparatus. An image position adjusting method for adjusting the position of an image formed on a first surface of paper and the position of an image formed on a second surface, the recording paper being adjusted by the print output means An image in which a position adjustment mark is arranged at a predetermined position is printed out on each of the first surface and the second surface of the recording paper, and the first surface and the second surface of the recording paper are printed out. When each is read by the image reading means, a deviation and inclination of the position of the recording paper in the reading area of the reading means are obtained as reading errors, and based on the errors, the first surface and the second surface are obtained. Process the images so that the faces match. Based on the image data, a shift amount between the image position of the first surface and the image position of the second surface is obtained, and the image on the first surface or the first surface is calculated based on the shift amount. It is characterized in that at least one of the recording positions is adjusted.

  According to the present invention, the image on which the position adjustment mark is arranged is formed on the first surface and the second surface of the recording paper by the print output device, and the image on the first surface and the first surface are recorded by the image reading unit. Each of the images on the second surface is read, and the image position misalignment between the first surface and the second surface is obtained from the image position adjustment mark on the first surface and the position adjustment mark on the second surface. The image position is adjusted based on this deviation.

  At this time, with respect to the images of the first and second surfaces read by the image reading means, a reading error is obtained from the deviation of the recording paper with respect to the image reading area 2, and image data is subjected to image processing based on the reading error. From this, the displacement of the image position between the first surface and the second surface is obtained.

  As a result, the image position deviation between the first surface and the second surface can be obtained from image data that does not include an error at the time of image reading, so that accurate image position adjustment can be performed.

  In the present invention, the first surface and the second surface may be front and back surfaces of recording paper fed from the same paper feed tray. The image formation and the image formation on the second surface may be performed by feeding the recording paper from different paper feed trays.

  That is, the present invention can be applied to adjustment of an image position when an image is formed by feeding recording paper from different paper feed trays, and adjustment of an image position during double-sided printing.

  Further, the present invention provides an image position on the first surface when the print output device forms and outputs an image on the recording paper based on RIP processed image data output from the image processing device. The output position of the RIP-processed image data is controlled on the basis of the amount of deviation between the image surface and the image position of the second surface, and the image position on the recording paper is adjusted.

  According to the present invention, when an image is formed on a recording sheet based on RIP-processed image data (raster data), the print output device is based on the displacement between the image positions of the first surface and the second surface. Controls the output timing of raster data. Thereby, an appropriate image can be formed at an appropriate position on the recording paper.

  In the present invention, the image formed on the first and second surfaces includes adjustment marks having line segments along the main scanning direction and the sub-scanning direction of the recording paper. If it is good.

  Such a mark is formed by crossing a predetermined length of a line segment along the vertical direction of the recording paper in the sub-scanning direction and the horizontal direction of the recording paper in the main scanning direction at a predetermined position. Can be used. Thereby, it is possible to easily and appropriately obtain the amount of deviation along the vertical and horizontal directions of the recording paper from the interval between the line segments.

  As described above, according to the present invention, the positional deviation or inclination of the recording paper when reading an image is obtained as a reading error, and the position of the image is determined based on the image data image-processed so as to eliminate the reading error. Since the adjustment is performed, an excellent effect that the image position can be accurately adjusted is obtained.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a copying machine 10 applied as an image forming apparatus to the present embodiment.

  The copying machine 10 includes a scanner unit 12 that reads an image recorded on a document, a print engine 14 provided as an image output device, and a control unit 16.

  In this embodiment, the copying machine 10 will be described as an example. The copying machine 10 is connected to a plurality of client terminals such as a personal computer (PC) via a network, and is output from the client terminal. A function of a print server that performs a printing process according to image data, or a function of outputting image data of an image read by the scanner unit 12 to a client terminal may be provided.

  As an image forming apparatus to which the present invention is applied, the scanner unit 12 may be provided separately and connected via a network or the like.

  The scanner unit 12 can apply a conventionally known configuration that reads an image recorded on the document 18 and outputs image data corresponding to the image of the document 18.

  A controller 22 is formed in the control unit 16 together with the image processing unit 20. Further, the control unit 16 is provided with an HDD 24 as a storage medium capable of storing image data input from the scanner unit 12 together with various data for executing various programs, image processing, and printing processing.

  The print engine 14 includes a paper feed unit 26. The paper feed unit 26 is provided with, for example, a plurality of paper feed trays 28, and recording paper 30 is stored in each paper feed tray 28. Forms an image on the recording paper 30 drawn from the paper feed tray 28 and sends it to the paper discharge tray 32.

  Note that the same size recording paper 30 or different size recording paper 30 can be loaded between the plurality of paper feed trays 28 of the paper feeding unit 26, and when different size recording paper 30 is stored, printing is performed. When the recording paper 30 of the size specified by the controller 22 is fed and the recording paper 30 of the same size is loaded, when the feeding of the recording paper 30 from one paper feed tray 28 is finished, the next feeding is performed. The recording paper 30 is fed from the paper tray 28.

  Such image formation in the print engine 14 is performed by scanning a laser beam based on the image data output from the image processing unit 20 in synchronization with the conveyance of the recording paper 30, and C (cyan), M (magenta), Y A toner image of each color of (yellow) and K (black) is formed, the toner image is transferred to an intermediate transfer member, and further transferred from the intermediate transfer member to the recording paper 30, thereby forming a color image on the recording paper 30. The general configuration to be formed can be applied.

  At this time, the controller 22 laser-images the image data based on the timing signal for each page output by the print engine 14 in synchronization with the conveyance of the recording paper 30 and the scanning signal for each scanning line in each page. Outputs one scan line of the beam at a time.

  As a result, the print engine 14 can form an image in a predetermined area on the recording paper 30.

  Further, the copying machine 10 is capable of duplex printing in which images are formed on both front and back sides of the recording paper 34 as a print option.

  When double-sided printing is set, the print engine 14 forms an image on the surface of the recording paper 30 and then reverses the recording paper 30 so that the back side of the recording paper 30 faces the intermediate transfer member. In accordance with this, the print controller 22 outputs image data of an image to be formed on the back surface of the recording paper 30 to the print engine 14 so that an image is formed on the back surface of the recording paper 30.

  Such a copying machine 10 can apply a conventionally known general mechanism and configuration, and can also apply a conventionally known mechanism as a transport mechanism of the recording paper 30 for performing double-sided printing. In this embodiment, the detailed configuration and mechanism of the copying machine 10 will be omitted.

  By the way, when an image is formed on the recording paper 30 by the print engine 14, the image forming position may be shifted due to a difference in a paper feed path of the recording paper 30. Such a shift appears as a difference in marginal margin width when an image is formed on the recording paper 30, and when the image is printed on both the front and back surfaces of the recording paper 30, It also appears as a deviation between the peripheral edge and the peripheral edge of the image area on the back side.

  From here, the controller 22 provided in the copying machine 10 adjusts the position of the image formed on the recording paper 30 by changing the image writing timing when the print engine 14 forms an image on the recording paper 30. I have to.

  On the other hand, as shown in FIG. 2, the controller 22 provided in the copying machine 10 includes an adjustment unit 40 that adjusts the image position when an image is formed on the recording paper 30, and a correction value that is an adjustment value of the adjustment unit 40. And a storage means 44 for storing a correction value calculated by the calculation means 42 is formed.

  In addition, image data read by the scanner unit 12 and subjected to predetermined image processing by the image processing unit 20 is input to the calculation unit 42. The calculation unit 42 receives the image data. Based on this, a correction value is calculated.

  The adjustment unit 40 corrects the output timing of the image data to the print engine 14 based on the correction value stored in the storage unit when an image is formed on the recording paper 34.

  As a result, the copying machine 10 moves the image position on the recording paper 30 to form an image in a predetermined area on the recording paper 30.

  The copying machine 10 stores a sample image for measuring the displacement of the image position on the recording paper 30. When the image position adjustment is performed, the sample image is printed on the recording paper 30. An output sample is created, and an image formed on the sample output is read by the scanner unit 12 and a correction value is calculated. Note that the sample image may be stored in the controller 22.

  3A and 3B show an example of sample output. The sample output 50 forms sample images 52 on the front surface 30A side and the back surface 30B side of the recording paper 30. 3A shows the front surface 30A side of the recording paper 30, and FIG. 3B shows the back surface 30B side of the recording paper 30.

  In the sample image 52, a deviation adjustment mark 54 is formed at a predetermined position. In the following description, when distinguishing the marks 54, the front surface 30A side is referred to as a mark 54A, and the back surface 30B side is referred to as a mark 54B.

  The mark 54 provided on the sample image 52 is formed in a cross shape in which a line segment 56A along the vertical direction (longitudinal direction) of the recording paper 30 and a line segment 56B along the horizontal direction (width direction) of the recording paper 30 cross each other. doing.

  In the print engine 14, for example, an image is formed with the longitudinal direction (vertical direction) of the recording paper 30 as a sub-scanning direction and the width direction (horizontal direction) of the recording paper 30 as a main scanning direction. Thereby, one corner of the recording paper 30 becomes the origin (for example, the origin P), and the sample image 52 is formed.

  Therefore, if there is no positional deviation between the sample image 52 on the front surface 30A side and the sample image 52 on the back surface 30B side, the marks 54A and 54B are at a fixed position with respect to the origin P.

  From here, in the copying machine 10, when the position adjustment is performed, each of the front surface 30A side and the back surface 30B side of the sample output 50 is read by the scanner unit 12, and between the marks 54A and 54B on the read image data. Calculate the deviation.

  In addition, when the image of the sample output 50 is read by the scanner unit 12, the copying machine 10 detects the edge of the recording paper 30, detects the deviation and inclination of the recording paper 30 as the deviation amount at the time of reading, The positions of 54A and 54B are corrected.

  As a result, only the amount of deviation between the image on the front surface 30A side and the image on the back surface 30B side when double-sided printing is performed on the recording paper 30 by the print engine 14 is obtained.

  Here, the adjustment of the image position on the recording paper 30 in the copying machine 10 will be described with reference to the drawings.

  In the copying machine 10, when performing image position adjustment, a sample output 50 is obtained in which the sample image 52 is printed on both sides of the recording paper 30. At this time, sample images 52 are formed on the front surface 30A and the back surface 30B of the sample output 50 (recording paper 30).

  Next, the sample output 50 is mounted on the scanner unit 12 to read an image formed on the recording paper 30 and obtain a reading error. That is, when the sample output 50 is mounted on the scanner unit 12, the sample output 50 may be tilted or slightly deviated from the normal position. For this reason, the mark output between the read image and the actual image The position of 54 may be displaced, and the amount of deviation at this time is obtained as a reading error.

As shown in FIG. 4, the reading error is obtained by extracting one side of the recording paper 30 with respect to the origin Q of the read image when the image is read by the scanner unit 12, and the points S ₁ and S ₁ at both ends of the one side. _Two two-dimensional coordinates (sx ₁ , sy ₁ ) and coordinates (sx ₂ , sy ₂ ) are obtained.

  From this, the position and inclination of the sample output 50 (recording paper 30) with respect to the image reading area can be obtained.

For example, from the coordinates (sx ₁ , sy ₁ ) of the point S ₁ , the deviation dx along the horizontal direction of the recording paper 30 is x ₁ (dx = x ₁ ), and the deviation dy along the vertical direction is y ₁ (dy = y ₁ ). Further, the inclination α of the recording paper 30 is calculated from the coordinates (sx ₁ , sy ₁ ) and (sx ₂ , sy ₂ ) of the points S ₁ and S ₂ , as follows: α = (sy ₂ −sy ₁ ) / (sx ₂ −sx Obtained as ₁ ).

Based on the reading error (deviations dx, dy and inclination α) obtained in this way, for example, image processing is performed so that the point S ₁ coincides with the origin Q and the inclination α = 0. Thereby, the reading error by the scanner unit 12 can be eliminated. Note that the reading error is eliminated for each of the image on the front surface 30A and the image on the back surface 30B.

  When the reading error is eliminated, as shown in FIG. 5, the reading origin Q (not shown in FIG. 5) of the image on the front surface 30A and the image on the back surface 30B is made coincident, so The registration widths dY and dX, which are deviations of the side mark 54B, are obtained.

Segment 56A forming the mark 54A, and 56B of the intersection R ₁ of the coordinates (x _1, y _1), line 56A that forms a mark 54B, 56B of the intersection R ₂ coordinates (x _2, y ₂ ), the misalignment between the mark 54A and the mark 54B is a registration width dX, which is a misalignment along the horizontal direction of the recording paper 30, and dX = (x ₂ −x ₁ ). The registration width dY that is a deviation along the line is dY = (y ₂ −y ₁ ).

  From here, the registration width dY, dX is set to “0” (dY = 0, dX = 0) so that the position when forming an image on the front surface 30A of the recording paper 30 and the back surface 30B of the recording paper 30 are set. Adjust the position of the image to be formed.

  The position adjustment at this time may move the image on the front surface 30A and the image on the back surface 30B by dY / 2 and dX / 2, respectively, with one of the front surface 30A or the back surface 30B as a reference and the other by dY and dX. It may be something that moves.

  On the other hand, when the position adjustment is performed, the copying machine 10 corrects the timing of outputting the image data to the print engine 14 when an image is formed on the recording paper 30 based on the registration widths dY and dX. That is, the arithmetic means 40 provided in the controller 22 calculates the output timing correction value T. As the correction value T, an image writing timing Tst and a scanning start timing Tss for each scanning line are set for each of the front surface 30A and the back surface 30B of the recording paper 30.

  The correction value T (writing start timing Tst, each scanning start timing Tss) calculated by the adjusting means 40 is stored in the storage means 44.

  The controller 22 of the copying machine 10 reads the correction value T stored in the storage means 44 when performing double-sided printing on the recording paper 30, and sets the timing when the image data is output to the print engine 14 as the correction value T. Control based on.

  FIG. 6 shows an outline of double-sided printing using the correction value T. In this flowchart, the positional difference between the image position of the front surface 30A and the image position of the back surface 30B is adjusted by adjusting the position of each of the front surface 30A and the back surface 30B of the recording paper 30. When one of 30B is used as a reference and the other is adjusted to that, the correction value T on the reference side may be set to “0”.

  This flowchart is executed when double-sided printing is designated. In the first step 120, the correction value T (correction values Tst, Tss) for the front surface 30A stored in the storage means 44 is read. The print start timing and the output timing of the image data for each scanning line are set.

  Thereafter, the process proceeds to step 124, and image printing on the front surface 30A is started. In step 126, it is confirmed whether or not image printing on the front surface 30A is finished.

  Here, when the image printing on the front surface 30A is completed, an affirmative determination is made in step 126, and the process proceeds to step 128. In this step 128, the correction value T (correction values Tst, Tss) set for the back surface 30B is read. In the next step 130, the printing start timing for the back surface 30B and the output timing of image data for each scanning line. Set.

  Thereafter, the process proceeds to step 132, image printing on the back surface 30B is started, and when the image printing on the back surface 30A is completed, an affirmative determination is made in step 134 and the double-sided printing is ended.

  FIG. 7A shows an outline of printing start timing on the front surface 30A and the back surface 30B during the printing process, and FIG. 7B shows an output timing of image data for each scanning line during the printing process. The outline of is shown.

As shown in FIG. 7A, the print engine 14 can perform printing processing at a predetermined timing according to the conveyance of the recording paper 30 (ON). Based on the signal indicating the page timing output from the print engine 14, the controller 22 is turned on to start transmission of image data. At this time, normally, the printing process is started at the timing of the standard value T ₀ .

  On the other hand, when adjusting the deviation of the recording paper 30 in the vertical direction (conveyance direction, sub-scanning direction), the image data transmission start timing (ON) by the correction value Tst set based on the registration width dY. Shift the timing.

  That is, when the image is shifted so that the margin on the leading edge side (downstream side in the transport direction) on the recording paper 30 is shifted, the printing start is advanced by the correction value Tst as shown by the broken line in FIG. When the image is shifted so that the margin 54 on the paper 30 becomes large, the start of printing is delayed by the correction value Tst as shown by a two-dot chain line in FIG.

  In addition, when printing is started, the controller 22 transmits image data for each scan line based on a scan start signal for each scan line output from the print engine 14. At this time, as shown in FIG. 7B, the image data is normally transmitted at the timing of the standard value Ts.

  On the other hand, when there is a deviation along the horizontal direction (main scanning direction) of the recording paper 30, image data transmission start timing (for each line) by the correction value Tss set based on the registration width dX ( On-time).

  That is, when the image is moved on the upstream side in the scanning direction on the recording paper 30, the image data transmission start timing is advanced by the correction value Tss relative to the standard value Ts, as indicated by a broken line in FIG. . Further, when the image is shifted downstream in the scanning direction on the recording paper 30, the start of image data transmission is delayed by the correction value Tss as shown by a two-dot chain line in FIG.

  Thereby, when double-sided printing is performed, it is possible to reliably prevent a deviation between the image position on the front surface 30A and the image position on the back surface 30B of the recording paper 30. Further, since the image is formed based on all the data subjected to the RIP process, the image formed on the recording paper 30 does not lack an image.

  In the present embodiment described above, the position adjustment when performing double-sided printing on the recording paper 30 has been described. However, the adjustment of the image position between the recording papers 30 accommodated in different paper feed trays 28 has been described. Can be applied.

  That is, when the recording paper 30 of the same size is fed between two different paper feed trays or between the paper feed tray and the manual feed tray, the image position may be misaligned due to a different conveyance path.

  At this time, for example, the recording paper 30 is fed from one paper feeding tray 28 to form a sample image 52 on the surface 30A of the recording paper, and then the recording paper 30 is fed from a different paper feeding tray 28. Thus, a sample image 52 is formed on the back surface 30B, and a sample output 50 is obtained.

  By reading the images of the front surface 30 </ b> A and the rear surface 30 </ b> B of the sample output 50 with the scanner unit 12, the image positions formed on the recording paper 30 can be matched between the different paper feed trays 28. That is, an image can be formed at a fixed position between the recording sheets 30 fed from the two sheet feeding trays 28.

  In addition, the recording paper 30 in which the sample image 52 is previously formed at a regular position on one side (for example, the back side 30B) is used, and the other side ( For example, a sample image 52 is formed on the surface 30A).

  By using this sample output 50, it is possible to adjust the printing position so that an image is formed at a certain position on the recording paper 30, so that the recording can be performed not only when performing double-sided printing but also when performing single-sided printing. An image can be formed at a certain position on the paper 30.

  In this embodiment, the mark 54 on the cross is formed on the sample image. However, the shape of the position adjustment mark is not limited to this, and at least the line segment 56A along the longitudinal direction of the recording paper 30 is used. As long as it includes the line segment 56B along the horizontal direction, the line segments 56A and 56B may be formed at positions separated without crossing.

  In the present embodiment, the output timing of the image data to the print engine 14 is controlled when adjusting the position of the image formed on the recording paper 30. However, the present invention is not limited to this. On the other hand, the conventional method of shifting the transfer origin, which is the actual image data transfer start position, can be used.

  At this time, there is a case where an image defect that a part of the object in the image formed on the recording paper 30 is applied may occur, and therefore, in the non-transfer area (non-print area) of the RIP processed image data (image data). It is preferable to check whether or not the pixels forming any object are included, and thereby the origin of the image data output to the print engine 14 is shifted with respect to the origin of the RIP-processed image data. When this is done, it is possible to prevent image defects.

  When pixels are included in the non-transfer area of the image data, the transfer origin may be shifted instead of shifting the transfer origin, and the image is not included in the non-transfer area. A transfer origin may be set.

  In addition, this Embodiment demonstrated above does not limit the structure of this invention. In this embodiment, the copying machine 10 is used as the image forming apparatus. However, the present invention is not limited to this, and the RIP-processed image data is output to an image output apparatus such as the print engine 14 on the recording paper. The image reading unit may include an image reading unit that forms an image and reads an image from a document image. The image reading unit may be connected to the image processing apparatus via a network.

1 is a schematic configuration diagram of a copying machine applied to the present embodiment. FIG. 2 is a functional block diagram illustrating a schematic configuration of a main part of a copying machine. (A) and (B) are schematic views showing sample output for position adjustment, (A) shows the front side of the recording paper, and (B) shows the back side of the recording paper. It is an image figure of the reading image which calculates | requires reading error. It is an image figure of the mark vicinity which calculates | requires the gap | deviation of an image position. 3 is a flowchart showing an outline of double-sided printing processing using a copying machine. (A) is a timing chart showing an outline of printing start timing, and (B) is a timing chart showing an outline of output timing of image data.

Explanation of symbols

10 Copy Machine 12 Scanner Unit (Image Reading Unit)
14 Print engine (print output device)
16 Control unit (image processing device)
20 Image processing unit 22 Controller 26 Paper feed unit (paper feed means)
28 Paper feed tray (paper feed means)
Reference Signs List 30 Recording paper 40 Adjustment means 42 Calculation means 44 Storage means 50 Sample output 52 Sample image 54 (54A, 54B) Mark (position adjustment mark)

Claims (5)

An image formed on the first surface of the recording paper when an image is formed on the recording paper fed from the paper feeding means of the printing output device based on the image data output from the image processing device to the printing output device And an image position adjustment method for adjusting the position of the image to be coincident with the position of the image formed on the second surface,
The print output means prints out an image in which a position adjustment mark is arranged at a predetermined position on each of the first surface of the recording paper and the second surface of the recording paper,
When each of the first surface and the second surface of the recording paper is read by the image reading means, a deviation and inclination of the position of the recording paper in the reading area of the reading means are obtained as reading errors,
Based on the error, the shift between the image position of the first surface and the image position of the second surface is performed based on the image data processed so that the first surface and the second surface coincide. Find the quantity
An image position adjustment method, wherein at least one of the first surface and the image recording position on the first surface is adjusted based on the amount of deviation.   2. The image position adjusting method according to claim 1, wherein the first surface and the second surface are front and back surfaces of recording paper fed from the same paper feed tray.   The image position adjustment according to claim 1, wherein the image formation on the first surface and the image formation on the second surface are performed by feeding the recording paper from different paper feed trays. Method.   When the print output device forms and outputs an image on the recording paper based on the RIP processed image data output from the image processing device, the image position of the first surface and the second surface The image position on the recording paper is adjusted by controlling the output timing of the RIP-processed image data based on the amount of deviation from the image position. The image position adjusting method according to any one of the above.   2. The image formed on the first and second surfaces includes an adjustment mark having a line segment along each of a main scanning direction and a sub scanning direction of the recording paper. The image position adjusting method according to claim 4.

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