JP2009104058A - Image-forming position adjusting device, image-forming apparatus, image-forming position adjustment method, image-forming position adjustiment program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image-forming apparatus, capable of surely performing resist-correction between the front face and the back face of paper, using a simple method. <P>SOLUTION: A patch colored in cyan is printed on the front face (A) of an OHP sheet, while a patch colored in magenta is printed on the back side (B), and the sheet is read by a scanner from the front face side. The patch on the front face is read as the reflected light to a light source. Since the OHP sheet is transparent, the patch on the back face is transmitted through the sheet and is read. When the patches on the both sides are printed without resist displacements, these patches are made to overlap with one another so as to render them blue. When resist displacement occurs, the patch colored in cyan and that colored in magenta are mutually displaced, and a cyan-colored area and a magenta-colored area appear (C). By detecting the amount of quantity and the amount of the location of the distributions of the cyan area and those of the magenta area, resist displacement quantity can be detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming position adjusting device, an image forming apparatus, an image forming position adjusting method, and an image forming position adjusting program, and more particularly to an image capable of correcting image misalignment when performing double-sided printing on a recording medium. The present invention relates to a forming position adjusting apparatus, an image forming apparatus, an image forming position adjusting method, and an image forming position adjusting program.

  Some image forming apparatuses (MFP (Multi Function Peripheral), facsimile machines, copiers, printers, etc.) have a duplex printing function. After the toner image is formed on the first side of the paper and fixed, the front and back sides of the paper are reversed, the toner image is formed on the second side of the paper, fixed, and discharged. is there.

Patent Document 1 below discloses a method in which images of correction patterns having the same size are output on the front surface and the back surface of a sheet, respectively, and a user measures the size deviation by measuring the dimensions of these images. The user inputs the measured deviation amount on the setting screen. When a desired image is actually output, an image whose size is corrected based on the amount of dimensional deviation is output.
JP 2004-54802 A

  In the conventional method described above, there is a problem that it takes time for measurement to calculate the deviation amount, which is complicated for the operator.

  The present invention provides an image forming position adjusting apparatus, an image forming apparatus, an image forming position adjusting method, and an image forming position adjusting program capable of reliably performing front and back resist correction by a simple method. It is an object.

  In order to achieve the above object, according to one aspect of the present invention, an image forming position adjusting apparatus reads a sheet on which a pattern for detecting resist deviation is printed on both sides, and is read by the reading unit. Detecting means for detecting a deviation amount between patterns printed on both sides of the paper based on an image of a pattern on the front surface of the paper and an image of a pattern on the back side of the paper read through the paper by the reading means; Prepare.

  Preferably, the image forming position adjusting apparatus further includes a calculation unit that calculates a registration correction amount in double-sided printing based on a shift amount between patterns detected by the detection unit.

  Preferably, the image forming position adjusting apparatus further includes a printing unit that prints a pattern for detecting a registration error on both sides of the sheet, and the reading unit reads the sheet on which printing has been performed by the printing unit.

  Preferably, the image forming position adjusting device further includes a correction unit that performs registration correction in double-sided printing based on the amount of deviation between patterns detected by the detection unit.

  Preferably, the reading unit includes a light source that irradiates the image surface of the paper and a sensor that detects reflected light or transmitted light of the light irradiated from the light source with respect to the image surface.

  Preferably, the paper is a transparent film.

  Preferably, the paper is plain paper.

  Preferably, the image forming position adjusting device includes a first double-sided printing registration error detection mode when a transparent film is used as paper, and a second double-sided printing registration error detection mode when plain paper is used as paper. Two modes can be selected.

  Preferably, when the second double-sided printing registration misalignment detection mode is selected, the image forming position adjusting device sets the light amount of the light source in the reading unit more than when the first double-sided printing registration misalignment detection mode is selected. Do more.

  According to another aspect of the present invention, an image forming apparatus includes the image forming position adjusting device described above.

  According to still another aspect of the present invention, an image forming position adjusting method includes a reading step of reading a sheet on which a pattern for detecting a resist deviation is printed on both sides, and a pattern on the surface of the sheet read in the reading step. And a detection step of detecting a shift amount between patterns printed on both sides of the paper based on the image of the pattern and the image of the pattern on the back side of the paper read through the paper in the reading step.

  According to still another aspect of the present invention, an image forming position adjusting program includes: a reading step for reading a sheet on which a pattern for detecting resist deviation is printed on both sides; a reading pattern on the surface of the sheet read in the reading step; And a detection step of detecting a shift amount between patterns printed on both sides of the paper based on the image of the image and the image of the pattern on the back side of the paper read through the paper in the reading step.

  According to these inventions, an image forming position adjusting device, an image forming apparatus, an image forming position adjusting method, and an image forming position adjusting program capable of reliably performing front and back resist correction by a simple method are provided. It becomes possible to do.

  [First Embodiment]

  FIG. 1 is a schematic diagram showing a configuration when the image forming apparatus according to the first embodiment of the present invention is viewed from the front.

  Here, the image forming apparatus is a copying machine. The copying machine includes an adjustment device that adjusts the image positions on both sides in duplex printing.

  The copying machine is provided with an automatic document feeder 1 at the top of the copying machine main body, and an image reading unit (scanner) 2, an image forming unit 3, a paper feeding unit 5, a paper discharge / switching unit 7, A recording paper storage unit 9 is provided.

  The automatic document feeder 1 is a device that feeds documents one by one, conveys them to an image reading position, and discharges the document after image reading to a predetermined location. The automatic document feeder 1 includes a document table 101 on which a document is placed, a document separation unit 103 that separates a placed document, a document transport unit 105 that transports a separated document, and a transported document. A document discharge unit 107, a document discharge stand 109 on which the discharged document is placed, and a document reversing unit 111 used to reverse the front and back of the document when reading images on both sides of the document are provided. .

  When scanning images on both sides of a document, the front and back of the document are reversed by a document reversing unit 111 including a pair of rollers that sandwich the trailing edge of the document on which the image on one side is sandwiched. After being read at the document reading position, it is discharged onto the document discharge table 109 as described above.

  The automatic document feeder 1 is configured to be retractable, and the document can be placed directly on the platen glass 203 by raising the automatic document feeder 1 and opening the platen glass 203. It is configured so that it can.

  Further, in this embodiment, the document conveying unit 105 is configured to read the image of the document while conveying the document, but the document conveyed via the document conveying unit 105 is stopped on the platen glass. Thereafter, the exposure optical system may be moved so that the image is read in the same manner as when the original is placed directly on the platen glass.

  The image reading unit 2 includes a light source 213 that irradiates light on an image surface of a document on the platen glass 203, a mirror 215 that reflects reflected light from the document surface of the document, and reflects light from the mirror 215 toward the CCD. Mirrors 217 and 219, a lens 209, and a CCD sensor 211.

  The light source 213 and the mirror 215 are included in the slider unit 205, and the mirrors 217 and 219 are included in the mirror unit 207.

  In the image reading unit 2, the reflected light of the light irradiated from the light source with respect to the image surface may be read by a sensor, or the transmitted light may be read by a sensor. For example, light may be applied from the back side of the document and the transmitted light may be read.

  In the present embodiment, the image forming unit 3 is a yellow (Y), magenta (M), cyan (C), and black (K) image forming unit (hereinafter referred to as a toner image corresponding to a color separation image). The image forming unit includes a photosensitive drum 301 that is an image forming body, a scorotron charger 303, an exposure optical system 313 that is an image writing unit, a developing device 311, and the like. It is configured as.

  The image forming unit 300 has a longitudinal direction (from the top, yellow, magenta, cyan, and so on) along one surface (the stretched surface A) of the intermediate transfer belt 401 that is long in the longitudinal direction in the upper portion of the recording paper storage unit 9. And in the order of black), the four sets have the same mechanical configuration. Therefore, in FIG. 1, only one set of components is given a reference symbol, and the other is omitted for convenience.

  The exposure optical system 313 is arranged on the downstream side in the rotation direction of the photosensitive drum 301 with respect to the scorotron charger 303. The exposure optical system 313 is an exposure unit composed of a laser optical system, and its configuration is well known.

  In image formation, for example, yellow (Y) image formation is performed as follows. The photosensitive drum 301 rotates counterclockwise by starting the photosensitive drum driving motor, and a potential is applied to the photosensitive drum 301 by the charging action of the scorotron charger 303. Thereafter, exposure corresponding to the first color signal, that is, the “Y” image signal is performed by the exposure optical system 313, and an electrostatic latent image corresponding to the “Y” image of the document is formed on the photosensitive drum 301. It is formed. The electrostatic latent image is reversely developed by the developing device 311 to be visualized.

  The “Y” toner image produced by reversal development is transferred onto the intermediate transfer belt 401 by a transfer device 305 provided opposite to the photosensitive drum 301 with the intermediate transfer belt 401 interposed therebetween.

  In the image formation using other color signals, the toner image produced by the magenta (M), cyan (C), and black (K) image forming units is a “Y” toner image by the same process as described above. The images are sequentially transferred so as to overlap with the image area, and a superimposed color toner image is formed on the intermediate transfer belt 401.

  In parallel with the image formation, the recording paper P is sent out by the paper feeding roller 903 (913, 923) from the feeding unit 901 (911, 921) of the recording paper storage unit 9, and is conveyed to the paper feeding registration roller 501.

  By feeding the registration roller 501, paper is fed so as to overlap with the color toner image area on the intermediate transfer belt 401, and the color toner image is formed on the recording paper P by the action of the second transfer unit 415 in the transfer area. Transcribed.

  A position measuring unit 510 that measures the amount of deviation of the recording paper P in the main scanning direction is provided between the paper feeding registration roller 501 and the second transfer unit 145.

The recording paper P to which the toner image has been transferred is separated from the peripheral surface of the intermediate transfer belt 401 and then conveyed to the fixing unit 601.
The toner image is melted by the heat and pressure of the fixing roller 603 and the pressure roller 605 having a heater therein, and is fixed on the recording paper P. The recording paper P after completion of the fixing process is conveyed by a fixing paper discharge roller 607 and a paper discharge roller 703 and discharged onto a paper discharge tray 705.

  The intermediate transfer belt 401 from which the recording paper P has been separated is neutralized by a static eliminator 407 provided facing a grounded conductive roller across the intermediate transfer belt 401, and then cleaned. The blade 413 is rubbed and cleaned.

  The toner remaining on the peripheral surface of the photosensitive drum 301 after the transfer is removed by the drum cleaning unit 309, and the history of the photosensitive drum 301 in the previous image formation is eliminated by a uniform exposure device (not shown) before charging. Thus, preparation for the next image formation is made.

  The recording paper storage unit 9 includes paper supply units 900, 910, and 920 that include storage containers 905, 915, and 925 that store a plurality of recording papers in a stacked state and feeding units 901, 911, and 921. It is arranged in the vertical direction. Each paper feed unit is arranged in parallel with the recording paper conveyance direction and close to the upper paper feed unit in the vertical direction by shifting the paper feed unit immediately below it to the downstream direction.

  The delivery parts 901, 911, and 921 are located on one side of the storage containers 905, 915, and 925, and have a structure that can be pulled out integrally.

  The feeding units 901, 911, and 921 are paper feeding rollers 903, 913 that are located in areas protruding from the upper side of the container when the paper feeding units 900, 910, and 920 are pushed into predetermined positions in the apparatus and loaded. , 923, and separation rollers 906, 916, 926 for preventing feeding of two sheets.

  The alternate long and short dash lines shown in the storage containers 905, 915, and 925 indicate the position of the uppermost sheet when a predetermined amount of the recording sheet P is stored.

  The paper feed unit 5 includes a plurality of transport units R1 for transporting the recording paper P from the storage containers 905, 915, and 925 that constitute a part of the paper feed units 900, 910, and 920 to the paper feed registration roller 501. , R2, R3, R4, R5, and R6, and each of the conveying sections is composed of a pair of rollers.

  The paper discharge / switching unit 7 is an area having a member for discharging or refeeding the recording paper P after image formation. The paper discharge / switching unit 7 is a fixing discharge roller 607 for discharging the recording paper P on which the toner image is fixed from the fixing unit 601, a switching unit 701 for switching the conveyance path, and paper discharge for discharging the recording paper P to the outside of the apparatus. A roller 703, a paper discharge tray 705 provided on the side of the apparatus main body on which the discharged recording paper P is stacked, a reversing unit 801 for reversing the front and back of the recording paper P to be reversed and an image of the reversed recording paper P A reverse conveyance unit 803 that re-feeds the sheet toward the forming unit 3 is provided.

  The switching unit 701 switches the conveyance path between when the recording paper P is discharged as it is, when the recording paper P is discharged after being turned upside down, and when the paper is fed again to form an image on the back surface of the recording paper P. It can be switched.

  When the image-formed recording paper P is discharged as it is, that is, with the image-formed surface facing upward, the switching unit 701 is positioned in the posture shown by the one-dot chain line in FIG. The recording paper P is discharged to a discharge tray 705 outside the apparatus by a fixing discharge roller 607 and a discharge roller 703.

  When the image-formed recording paper P is reversed and discharged, that is, when the image-formed surface is discharged downward, the switching unit 701 is positioned in the posture shown by the solid line in FIG. The recording paper P conveyed by the roller 607 is once conveyed in the direction of the reversing unit 801. Subsequently, after the recording paper P passes through the switching unit 701, the recording paper P is switched back and discharged to a discharge tray 705 outside the apparatus by a discharge roller 703.

  Further, when an image is formed on the back surface of the recording paper P, the switching unit 701 is positioned at a position indicated by a solid line in FIG. 1, and the recording paper P conveyed by the fixing discharge roller 607 is conveyed in the direction of the reversing unit 801. Then, the reversing unit 801 performs the switchback and reverses the front and back, and then conveys it to the reversing conveyance unit 803.

  The recording paper P transported to the reverse transport unit 803 is transported by the transport roller 503 to the paper feed registration roller 501 through the transport path similar to that of paper feed from the paper feed units 900, 910, and 920. It is conveyed to the transfer unit 415.

  The copier also includes a control device 351 including a CPU, RAM, ROM, etc. for controlling the entire apparatus, a liquid crystal display device for displaying information to the user, and a touch panel for receiving input from the user. 251.

  FIG. 2 is a flowchart showing processing in the double-sided printing registration correction mode.

  This processing is for performing registration correction (alignment of images on both sides) for double-sided printing in an image forming apparatus having a double-sided printing function. Specifically, a predetermined pattern is printed on each of the front and back surfaces of the OHP sheet, the printed pattern is read by a scanner, and the resist deviation amount between the front and back surfaces is calculated from the read data. Registration correction is performed according to the calculated value. As a result, the shift amount can be automatically detected, and correction can be performed based on this. The OHP sheet is a specific example of a transparent film as a copy sheet. A translucent film or the like may be used as long as the sheet transmits light.

  Referring to FIG. 2, when the operator selects the duplex printing registration correction mode from operation panel 251, duplex printing registration correction mode starts (S10). On the operation panel 251, a message “Please confirm that there is an OHP sheet in the paper feeding unit A and press the copy start button” is displayed (S 11). Thereafter, it waits for the copy start button to be pressed (S12).

  Until the copy start button is pressed, the process of step S12 is repeated and the display of the message is continued. When the copy start button is pressed, an image forming operation (double-sided printing) is started (S13). First, an OHP sheet is fed from the sheet feeding unit A (S14), and a predetermined test pattern is printed on the front surface and the back surface at predetermined timings (S15, S16). Here, the test pattern printed on the front side is called “test pattern A”, and the test pattern printed on the back side is called “test pattern B”.

  When the OHP sheet with the test pattern printed on both sides is discharged, a message “Place the printed test pattern on the platen glass and press the copy start button” is displayed on the operation panel (S17). The process waits until the copy start button is pressed (S18). When the copy start button is pressed, reading of the OHP sheet on which the test pattern is printed is started (S19).

  The registration deviation amount for double-sided printing is detected from the color distribution of the read image data (S20). The double-sided printing registration correction amount is determined from the detected registration deviation amount (S21), and the double-sided printing registration correction mode is terminated (S22).

  FIG. 3 is a diagram showing a test pattern printed on the OHP sheet.

  As shown in (A), a cyan patch (test chart) is printed at the center on the surface of the OHP sheet, and a magenta patch (test chart) is printed on the back as shown in (B). . This sheet is read from the surface by an image reading unit (scanner).

  The patch on the surface is read as reflected light with respect to the light source by the image reading unit. Since the OHP sheet is transparent, the patch on the back surface is read through the paper.

  When the patches on both sides are printed with no registration error, the patches are arranged so that these patches just overlap to form a blue patch (a blue patch is printed).

  If registration deviation occurs, cyan and magenta patches are displaced as shown in FIG. 3C, and cyan, magenta, and blue regions are generated. In this case, it is possible to detect the registration deviation amount by detecting to which side the cyan area and the magenta area are distributed.

  In FIG. 3, a black triangular pattern is arranged in the upper right corner of the surface (A). This is to prevent the operator from placing the OHP sheet in the wrong direction when placing the OHP sheet on which the test pattern is printed on the platen glass.

  Here, the registration deviation amount is detected from the color distribution. However, since the brightness values of cyan, magenta, and blue are known in advance, the registration deviation amount may be detected from the brightness distribution.

  FIG. 4 is a flowchart showing registration correction processing.

  Referring to the figure, when performing double-sided printing, the double-sided printing is performed with the position of the image on the back side or front side (or both sides) corrected based on the registration correction amount determined in step S21 of FIG. 2 (S101). Printing is executed (S103).

  For example, in the correction process, during double-sided printing, the exposure unit is instructed to control the backside printing timing so that the writing position is the same as the front side printing position. Alternatively, the back image may be processed on the data so that the same writing position is obtained.

  [Second Embodiment]

  Since the configuration of the image forming apparatus in the second embodiment is the same as that in the first embodiment, description thereof will not be repeated here. In the second embodiment, plain paper is used instead of an OHP sheet for aligning images on both sides.

  FIG. 5 is a flowchart showing processing in the double-sided printing registration correction mode in the second embodiment.

  The processes in steps S30, S32 to S34, and S37 to S42 in FIG. 5 are the same as the processes in steps S10, S12 to S14, and S17 to S22 in FIG.

  In FIG. 5, in step S31, a message “Please confirm that plain paper is in paper feed unit A and press the copy start button” is displayed on operation panel 251. In step S35, the test pattern C is printed on the front surface of the plain paper, and in step S36, the test pattern D is printed on the back surface thereof. In this way, plain paper is used in the same processing flow as in the first embodiment.

  FIG. 6 is a diagram showing a test pattern printed on plain paper in the second embodiment.

  Here, the test patterns C and D are both solid patches of the same size as black. When the plain paper on which the test pattern is printed is viewed from the front side, the black solid patch printed on the back side can be seen through (FIG. 6C).

  When the registration error occurs, as shown in FIG. 6C, a dark black region and a gray region (a portion where the back surface patch can be seen through) are generated. The amount of resist deviation can be detected from these distributions.

  When reading plain paper on which a test pattern is printed, it is desirable to increase (increase) the amount of illumination light of the scanner (the amount of illumination light that illuminates the paper) than during normal reading. This is to make it easier to detect the black solid on the back surface.

  [Third Embodiment]

  Since the configuration of the image forming apparatus in the third embodiment is the same as that in the first embodiment, description thereof will not be repeated here. In the third embodiment, an OHP sheet or plain paper is used to align the images on both sides. That is, the operator (user) can select either an OHP sheet or plain paper as a medium for printing a test pattern.

  7 and 8 are flowcharts showing processing in the double-sided printing registration correction mode in the third embodiment.

  The processing in steps S50, S53 to S59, and S70 to S73 in FIG. 7 is the same as the processing in steps S10, S12 to S18, and S19 to S22 in FIG. Further, the processing in steps S62 to S68 in FIG. 8 is the same as the processing in steps S32 to S38 in FIG.

  The correction using plain paper is slightly inferior in accuracy to the correction using an OHP sheet because it detects the black solid on the back side. Therefore, when the double-sided printing registration correction mode is started (S50), the operator is warned whether the OHP sheet can be used (S51). When the operator selects correction using the OHP sheet, a message “Please insert an OHP sheet into the paper feeding unit A and press the copy start button” is displayed on the operation panel 251 in step S52. Thereafter, correction using an OHP sheet is performed as in the first embodiment.

  At this time, test patterns to be printed are test pattern A and test pattern B shown in FIG.

  If the operator selects correction using plain paper instead of an OHP sheet (NO in S51), in step S61 (FIG. 8), “Plain paper is put in the paper feeding unit A and a copy start button is displayed on the operation panel 251”. Please press "message appears. After that, correction using plain paper is performed as in the second embodiment.

  At this time, the test patterns to be printed are the test pattern C and the test pattern D shown in FIG.

  Also, the light amount setting of the scanner light source when reading the printed test pattern is different between the correction using the OHP sheet and the correction using plain paper. More specifically, assuming that the light amount setting at the time of correction using the OHP sheet is A and the light amount setting at the time of correction using plain paper is B, the light amount is set to satisfy A <B (S60, S69).

  This is because the correction with plain paper requires a higher amount of light in order to detect the black solid on the back side.

  [Effects of the embodiment]

  As described above, in the above-described embodiment, a predetermined pattern is printed on both sides of a medium (transparent film or plain paper). By automatically detecting the registration deviation amount on both sides from the image data obtained by reading the printed pattern, it is possible to reliably perform registration correction on the front and back sides with a simple procedure.

  [Others]

  In the above-described embodiment, the copying machine provided with the image reading unit on the upper side has been described as an example. However, the image reading unit may be installed inside the image forming apparatus.

  The present invention can be implemented for an image forming apparatus such as a monochrome / color copying machine, a FAX, or a multifunction peripheral.

  Further, the present invention can be applied to a scanner (image reading apparatus) that reads a sheet on which double-sided printing of a test pattern is performed and obtains a pattern shift amount and a double-sided resist correction amount.

  Further, in printing a test pattern, image data stored in the apparatus may be printed, or a test pattern document on which both sides of the pattern are printed is read and printed. It is good as well.

  In the above-described embodiment, the user sets and reads the image of the paper on which double-sided printing has been performed. However, for example, a sensor is provided at the position of the paper discharge roller 703 in FIG. It is good as well.

  As the paper used in the image forming apparatus, tracing paper, semi-paper, etc. may be used in addition to the OHP sheet and plain paper.

  Further, the processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic diagram illustrating a configuration when an image forming apparatus according to a first embodiment of the present invention is viewed from the front. It is a flowchart which shows the process in double-sided printing registration correction mode. It is a figure which shows the test pattern printed on an OHP sheet. It is a flowchart which shows a resist correction process. It is a flowchart which shows the process in the double-sided printing registration correction mode in 2nd Embodiment. It is a figure which shows the test pattern printed on plain paper in 2nd Embodiment. It is a flowchart which shows the process in the double-sided printing registration correction mode in 3rd Embodiment. It is a flowchart following FIG.

Explanation of symbols

1 Automatic document feeder
2 Image Reading Unit 3 Image Forming Unit 5 Paper Feeding Unit 7 Paper Discharge / Switching Unit 9 Recording Paper Storage Unit 101 Document Placement Table 103 Document Separation Unit 105 Document Transport Unit 107 Document Paper Discharge Unit 109 Document Output Unit 111 Document Reversing Unit 203 Platen glass 300 Image forming unit 301 Photosensitive drum 303 Scorotron charger 305 Transfer device 309 Drum cleaning unit 311 Developer 313 Exposure optical system 401 Intermediate transfer belt 407 Electric discharger 413 Cleaning blade 415 Second transfer unit 501 Paper registration roller 510 Position Measuring unit 601 Fixing unit 603 Fixing roller 605 Pressure roller 607 Fixing paper discharge roller 703 Paper discharge roller 705 Paper discharge tray 801 Reversing unit 803 Reverse conveying unit 903 Paper feeding roller 900, 910, 920 Paper feeding unit

Claims (12)

A reading means for reading from one side of a sheet on which a pattern for detecting a resist deviation is printed on both sides;
A pattern printed on both sides of the paper based on the image of the pattern on the front surface of the paper read by the reading means and the image of the pattern on the back surface of the paper read through the paper by the reading means. An image forming position adjusting apparatus, comprising: a detecting unit that detects an amount of deviation between each other.   The image forming position adjusting apparatus according to claim 1, further comprising a calculating unit that calculates a registration correction amount in double-sided printing based on a shift amount between patterns detected by the detecting unit. The printer further includes a printing unit that prints a pattern for detecting registration deviation on both sides of the paper.
The image forming position adjusting apparatus according to claim 1, wherein the reading unit reads a sheet on which printing has been performed by the printing unit.   4. The image forming position adjusting apparatus according to claim 1, further comprising a correcting unit that performs registration correction in double-sided printing based on a shift amount between patterns detected by the detecting unit. The reading means includes
A light source for illuminating the image surface of the paper;
The image forming position adjusting device according to claim 1, further comprising: a sensor that detects reflected light or transmitted light of the light emitted from the light source with respect to an image surface.   The image forming position adjusting apparatus according to claim 1, wherein the sheet is a transparent film.   The image forming position adjusting device according to claim 1, wherein the paper is plain paper.   Two modes can be selected: a first double-sided printing registration deviation detection mode when a transparent film is used as the paper, and a second double-sided printing registration deviation detection mode when plain paper is used as the paper. The image forming position adjusting device according to claim 1.   9. The light source of the light source in the reading unit when the second double-sided printing registration deviation amount detection mode is selected is greater than when the first double-sided printing registration deviation amount detection mode is selected. Image forming position adjusting device.   An image forming apparatus comprising the image forming position adjusting device according to claim 1. A reading step of reading from one side a sheet on which a pattern for detection of registration deviation is printed on both sides;
A pattern printed on both sides of the paper based on the image of the pattern on the front surface of the paper read in the reading step and the image of the pattern on the back surface of the paper read through the paper in the reading step A method for adjusting an image forming position, comprising: a detecting step for detecting a shift amount between each other. A reading step of reading from one side a sheet on which a pattern for detection of registration deviation is printed on both sides;
A pattern printed on both sides of the paper based on the image of the pattern on the front surface of the paper read in the reading step and the image of the pattern on the back surface of the paper read through the paper in the reading step An image forming position adjustment program that causes a computer to execute a detection step of detecting a deviation amount between each other.

Images