JP2021145377A - Image forming system - Google Patents

Abstract

To provide an image reading device, an image forming system, and a program that can read the front and back positions of images formed on a sheet accurately at a low cost, and can easily detect sudden displacement of the front and back positions of the images.SOLUTION: Marks A are formed on the front and back of a sheet P, respectively, by an image forming apparatus 5, and an image reading device 7 comprises: a first scanner 701a that reads the mark A; and a second scanner 701b that is provided on the downstream side of the first scanner 701a and reads the mark A. The image reading device includes a position adjustment unit 511 that adjusts the front and back positions of the marks A on the basis of printing positions of the marks A read by at least one of the first scanner 701a and second scanner 701b, and a monitoring unit 513 that monitors displacement of the front and back positions of the marks A on the basis of the front and back positions of the marks A adjusted by the position adjustment unit 511.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image reader, an image forming system, and a program.

Conventionally, in an image forming system including a printing machine capable of double-sided printing and an image reading device including a scanner, one scanner is used to measure and adjust the front and back positions of an image formed on paper (for example). , Patent Document 1).

In the prior art as described in Patent Document 1, the paper is conveyed twice in order to read the front and back positions of the image formed on the paper with one scanner. Therefore, as the operation of reading the front and back positions of the image is performed for each paper, the time required for transporting to read the image formed on the paper increases. As a result, the productivity of the image forming system is reduced.

Therefore, in order to avoid transporting the paper twice for each paper, there is one that uses two scanners to read the front and back positions of the image formed on the paper. Specifically, one of the two scanners is made to read the image formed on the front surface of the paper, and the other of the two scanners is made to read the image formed on the back surface of the paper. As a result, the images formed on the front and back sides of the paper can be read by transporting the paper once per sheet of paper.

Japanese Unexamined Patent Publication No. 2006-072075

However, each scanner has a mechanical difference, that is, a mechanical difference. Therefore, even if two scanners having the same performance are used to read the images formed on the front and back sides of the paper, the reading positions of the two scanners may be misaligned. Therefore, the front and back positions of the image formed on the paper may not be accurately read.

Further, when the mechanical difference of the scanner is mechanically adjusted, the component accuracy and the position accuracy are required to be high, so that the cost of adjusting the mechanical difference of the scanner increases.

By the way, as double-sided printing is performed by the printing machine, front and back misalignment may occur in the images formed on both sides of the paper even though the setting on the printing machine side is not changed. Such misalignment of the front and back of the image occurs due to environmental conditions such as temperature and humidity of the printing place or deterioration of machine durability. Therefore, the front and back misalignment of the image due to the environmental conditions may occur suddenly.

The present invention has been made to solve a conventional problem, and an object of the present invention is to accurately read the front and back positions of an image formed on paper at low cost, and to perform sudden front and back positions of an image. It is an object of the present invention to provide an image reader, an image forming system, and a program capable of easily detecting a deviation.

In order to achieve the above object, the image reading device according to the present invention comprises a first scanner that reads an image formed on paper, a downstream side of the first scanner, and a transport path for passing the paper. An image reading device provided on the opposite side of the first scanner and including a second scanner for reading an image formed on the paper, which is formed on the first surface of the paper read by the first scanner. Based on the printing position of the mark and the printing position of the mark formed on the first surface of the paper read by the second scanner, or read by the first scanner, the positional relationship is the same from the front and back. The first scanner and the said The first reference, which is the reference position of the mark formed on the first surface of the paper when the machine difference is adjusted by the machine difference adjusting unit for adjusting the machine difference with the second scanner and the machine difference adjusting unit. A position adjusting unit that determines a position and a second reference position that is a reference position of a mark formed on the second surface of the paper, the first reference position determined by the position adjusting unit, and the first reference position. The first reference deviation amount, which is the deviation amount from the printing position of the mark formed on the first surface of the paper read by the scanner, is monitored, and the second reference position determined by the position adjusting unit and the said It is provided with a monitoring unit for monitoring a second reference deviation amount, which is an deviation amount from the printing position of a mark formed on the second surface of the paper read by the second scanner.

According to this image reading device, it is possible to accurately read the front and back positions of an image formed on paper at low cost, and easily detect a sudden front and back position shift of the image.

Further, in the image reading device according to the present invention, the first scanner and the first scanner are based on the printing position of the mark read by the first scanner and the printing position of the mark read by the second scanner. 2 The machine difference adjusting unit for adjusting the machine difference with the scanner is further provided, and the position adjusting unit monitors the front and back misalignment of the mark by the monitoring unit when the machine difference is adjusted by the machine difference adjusting unit. It is preferable to determine the adjustment reference position of the mark, which is the reference of the above.

According to this image reading device, it is possible to shorten the time required to detect the front-back positional deviation of the mark as compared with the case where one scanner transports the image twice.

Further, in the image reading device according to the present invention, it is preferable that the machine difference adjusting unit adjusts the machine difference based on the mark formed on the same surface of the paper.

According to this image reading device, it is possible to accurately detect the difference between the scanners.

Further, in the image reading device according to the present invention, when the monitoring unit monitors the front-back position deviation of the mark formed on the paper, the monitoring unit is among the adjustment reference positions of the mark determined by the position adjusting unit. The first adjustment reference deviation between the first adjustment reference position of the mark formed on the first surface of the paper and the printing position of the mark formed on the first surface of the paper read by the first scanner. While monitoring the amount, the second adjustment reference position of the mark formed on the second surface of the paper among the adjustment reference positions of the mark determined by the position adjustment unit and the second adjustment reference position of the mark are read by the second scanner. The second adjustment reference deviation amount from the printing position of the mark formed on the second surface of the paper is monitored, and the position adjustment unit receives the first adjustment reference deviation amount monitored by the monitoring unit. It is preferable to adjust the front and back positions of the marks based on the second adjustment reference deviation amount monitored by the monitoring unit.

According to this image reading device, it is possible to monitor the front and back misalignment of the mark at low cost.

Further, in the image reading device according to the present invention, when the machine difference is adjusted, the master original is used as the paper, and the printing position of the mark formed on the first surface of the master original and the printing position of the master original. Each of the printing positions of the marks formed on the second surface is formed at the same position in the front and back penetrating directions of the paper, and the machine difference adjusting unit is read by the first scanner. The machine difference is determined based on the printing position of the mark formed on the first surface of the master document and the printing position of the mark formed on the second surface of the master document read by the second scanner. When the machine difference is adjusted by the machine difference adjusting unit using the master document, the position adjusting unit sets the printing position of the mark formed on the master document as the adjustment reference position of the mark. Is preferably set at the design reference position of the mark.

According to this image reading device, it is possible to accurately adjust the difference between the scanners and the front and back positions of the marks.

Further, in the image reading device according to the present invention, the monitoring unit is formed on the first surface of the paper read by the first scanner when monitoring the front-back positional deviation of the mark formed on the paper. The first design reference deviation between the printed position of the mark and the first design reference position of the mark formed on the first surface of the master document among the design reference positions of the mark set by the position adjusting unit. While monitoring the amount, the master document out of the printing position of the mark formed on the second surface of the paper read by the second scanner and the design reference position of the mark set by the position adjusting unit. The second design reference deviation amount with respect to the second design reference position of the mark formed on the second surface of the above is monitored, and the position adjusting unit receives the first design reference deviation amount monitored by the monitoring unit. It is preferable to adjust the front and back positions of the marks based on the second design reference deviation amount monitored by the monitoring unit.

According to this image reading device, it is possible to accurately monitor the front and back misalignment of the mark.

Further, in the image reading device according to the present invention, the position adjusting unit is read by the printing position of the mark formed on the first surface of the paper read by the first scanner and by the first scanner. When the front and back positions of the mark are adjusted based on the printing position of the mark formed on the second surface of the paper, the adjustment reference of the mark, which is the reference for monitoring the front and back misalignment of the mark by the monitoring unit. It is preferable to determine the position.

According to this image reading device, it is possible to monitor the front and back misalignment of the mark without being affected by the difference between the scanners.

Further, in the image reading device according to the present invention, when the monitoring unit monitors the front-back positional deviation of the mark, the second scanner reads the mark formed on the paper, and the monitoring unit reads the mark. When monitoring the front-back position deviation of the mark formed on the paper, the adjustment reference position of the mark determined by the position adjusting unit and the printing position of the mark read by the second scanner are adjusted. It is preferable that the amount is monitored and the position adjusting unit adjusts the front and back positions of the mark based on the adjustment reference deviation amount monitored by the monitoring unit.

According to this image reading device, it is possible to monitor the front and back misalignment of the mark particularly remarkably without being affected by the difference between the scanners.

Further, in order to achieve the above object, the image forming system according to the present invention includes an image forming unit that forms an image on the front and back sides of the paper, a first scanner that reads the image formed on the paper, and the first scanner. An image forming system including a second scanner provided on the downstream side and on the side opposite to the first scanner with a transport path for passing the paper, and reading an image formed on the paper. Based on or based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or The print position of the mark formed on the first surface of the document read by the first scanner and the positional relationship can be read from the front and back with the same reference, and the mark formed on the second surface of the document read by the second scanner. A machine difference adjusting unit that adjusts the machine difference between the first scanner and the second scanner based on the printing position of the marked mark, and when the machine difference is adjusted by the machine difference adjusting unit, the paper A position adjusting unit that determines a first reference position, which is a reference position of a mark formed on a first surface, and a second reference position, which is a reference position of a mark formed on the second surface of paper, and the position. The first reference deviation amount, which is the deviation amount between the first reference position determined by the adjusting unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. The second reference deviation amount, which is the deviation amount between the second reference position determined by the position adjusting unit and the printing position of the mark formed on the second surface of the paper read by the second scanner, is monitored. It is equipped with a monitoring unit.
Further, in the image forming system according to the present invention, the position adjusting unit is a paper based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. It is preferable to give feedback to the image forming portion for adjusting the printing position when the mark is formed.
Further, in the image forming system according to the present invention, the machine difference adjusting unit is read by the printing position of the mark formed on the first surface of the paper read by the first scanner and by the second scanner. It is preferable to adjust the difference between the first scanner and the second scanner based on the printing position of the mark formed on the first surface of the paper.
Further, in the image forming system according to the present invention, a reversing path for reversing the paper is provided between the first scanner and the second scanner, or on the upstream side of the first scanner, and the machine difference adjusting unit provides the reversing path. When the machine difference is adjusted, the first scanner reads the image formed on the paper not inverted by the inversion path, and the second scanner reads the image formed on the paper inverted by the inversion path. It is preferable to read.
Further, in the image forming system according to the present invention, the machine difference adjusting unit is based on the mark formed on the first surface of the same paper read by the first scanner and the second scanner. It is preferable to adjust.
Further, in the image forming system according to the present invention, the machine difference adjusting unit determines the machine difference based on the marks formed on the first surface of different papers read by the first scanner and the second scanner. It is preferable to adjust.
Further, in the image forming system according to the present invention, the machine difference adjusting unit has a printing position of a mark formed on the first surface of a document read by the first scanner and a document read by the second scanner. It is preferable to adjust the difference between the first scanner and the second scanner based on the printing position of the mark formed on the second surface of the above.
Further, in the image forming system according to the present invention, the position adjusting unit is the first reference position based on the printing position of the mark formed on the manuscript when the machine difference is adjusted by the machine difference adjusting unit. And the second reference position are preferably determined.

According to this image forming system, it is possible to easily detect a sudden front-back misalignment of an image while accurately reading the front-back position of an image formed on paper at low cost, as in the case of an image reading device. can.

Further, according to this image forming system, it is possible to provide a low-cost feedback system as a whole system.

Further, in order to achieve the above object, the program according to the present invention comprises a first scanner that reads an image formed on paper and a transport path that is downstream of the first scanner and that allows the paper to pass through. A computer for controlling an image reading device provided with a second scanner provided on the opposite side of the first scanner and reading an image formed on the paper is formed on the first surface of the paper read by the first scanner. Based on the printed position of the marked mark and the printed position of the mark formed on the first surface of the paper read by the second scanner, or based on the same reference from the front and back as read by the first scanner. The first scanner is based on the printing position of the mark formed on the first surface of the document from which the positional relationship can be read and the printing position of the mark formed on the second surface of the document read by the second scanner. This is the reference position of the mark formed on the first surface of the paper when the machine difference is adjusted by the machine difference adjusting unit for adjusting the machine difference between the and the second scanner and the machine difference adjusting unit. A position adjusting unit that determines one reference position, a second reference position that is a reference position of a mark formed on the second surface of the paper, the first reference position determined by the position adjustment unit, and the above. The first reference deviation amount, which is the deviation amount from the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored, and the second reference position determined by the position adjusting unit is used. The purpose is to function as a monitoring unit for monitoring a second reference deviation amount, which is an amount of deviation from the printing position of the mark formed on the second surface of the paper read by the second scanner.

According to this program, it is possible to easily detect a sudden front-back position shift of an image while accurately reading the front-back position of an image formed on paper at low cost, as in the case of an image reading device.

According to the present invention, it is possible to easily detect a sudden front-back position shift of an image while accurately reading the front-back position of an image formed on paper at low cost.

It is a figure which shows an example of the whole structure of the image formation system 1 in Embodiment 1 of this invention. It is a figure which shows the structural example of the image forming apparatus 5 in Embodiment 1 of this invention. It is a figure which shows the structural example of the image reading apparatus 7 in Embodiment 1 of this invention. It is a figure which shows the functional structure example of the control part 51 in Embodiment 1 of this invention. It is a figure which shows an example of the mark A formed on the paper P in Embodiment 1 of this invention. It is a figure which shows an example which transports the same paper P in the transport path 700 of the paper P in Embodiment 1 of this invention. It is a flowchart explaining the control example in Embodiment 1 of this invention. It is a figure which shows the front-back position adjustment example of the mark A in Embodiment 1 of this invention. It is a figure which shows an example which different paper P is conveyed in the transport path 700 of the paper P in Embodiment 1 of this invention. It is a figure which shows an example of the transport path 700 of the paper P in Embodiment 2 of this invention. It is a flowchart explaining the control example in Embodiment 2 of this invention. It is a figure which shows the front-back position adjustment example of the mark A in Embodiment 2 of this invention. It is a figure which shows an example which different paper P is conveyed in the transport path 700 of the paper P in Embodiment 3 of this invention. It is a flowchart explaining the control example in Embodiment 3 of this invention. It is a figure which shows the front-back position adjustment example of the mark A in Embodiment 3 of this invention. It is a figure which shows an example which transports the same paper P in the transport path 700 of the paper P in Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

Embodiment 1.
FIG. 1 is a diagram showing an example of the overall configuration of the image forming system 1 according to the first embodiment of the present invention. As shown in FIG. 1, the image forming system 1 includes a paper feeding device 3, an image forming device 5, an image reading device 7, and a paper ejection device 8. The paper feeding device 3 feeds the paper P to the image forming device 5. The image forming apparatus 5 forms an image on the paper P fed from the paper feeding device 3. The image reading device 7 reads the paper P on which the image is formed by the image forming device 5 and executes various processes. The paper ejection device 8 includes a paper ejection tray 9, and ejects the paper P conveyed from the image reading device 7 to the paper ejection tray 9.

Next, the image forming apparatus 5 will be specifically described. FIG. 2 is a diagram showing an example of the internal configuration of the image forming apparatus 5 according to the first embodiment. As shown in FIG. 2, the image forming apparatus 5 is an example of a color copier, which acquires image information by reading a color image formed on a document T, and superimposes colors based on the acquired image information. , A device that forms a color image. The image forming apparatus 5 is suitable for application to a color printer or a facsimile apparatus, a multifunction device thereof, or the like, in addition to a color copier.

The image forming apparatus 5 includes an image forming apparatus main body 11. An image reading unit 12 for color and an automatic document feeder 14 are arranged on the upper part of the image forming apparatus main body 11. The image forming apparatus main body 11 includes a control unit 41, an image processing unit 43, an image forming unit 60, a paper feeding unit 20, and a conveying unit 30, although details will be described later.

Next, the automatic document feeder 14 will be described. The automatic document feeder 14 is provided on the image reading unit 12 and performs an operation of automatically feeding one or a plurality of documents T in the automatic paper feeding mode. Here, the automatic paper feed mode is an operation of feeding the document T placed on the automatic document feeder 14 and reading the image printed on the document T.

Specifically, the automatic document feeder 14 includes a document placing section 141, a roller 142a, a roller 142b, a roller 143, a roller 144, a reversing section 145, and a paper ejection tray 146. One or a plurality of original documents T are placed on the document placing section 141. Rollers 142a and 142b are provided on the downstream side of the document placing portion 141. A roller 143 is provided on the downstream side of the roller 142a and the roller 142b. Further, the automatic document feeder 14 includes a positioning detection unit 81 on the outer peripheral side of the roller 143.

When the automatic paper feed mode is selected, the document T fed out from the document placing unit 141 is conveyed by rotating the document T in a U shape by the roller 143. When the document T is placed on the document placing section 141 and the automatic paper feed mode is selected, the recording surface of the document T is preferably facing upward.

Further, the document T is read by the image reading unit 12 and then conveyed by the roller 144 and discharged to the paper ejection plate 146. By transporting the document T to the reversing section 145, the automatic document feeding device 14 can cause the image reading unit 12 to read not only the recording surface of the document T but also the back surface side of the recording surface of the document T.

Next, the positioning detection unit 81 will be described. The positioning detection unit 81 detects the document T on which the image is printed. The positioning detection unit 81 is composed of, for example, a reflective photo sensor. When the document T is detected, the positioning detection unit 81 raises an output signal, and when the document T is no longer detected, the output signal falls, and the result is transmitted to the control unit 41. That is, the output signal maintains a constant value during the period when the document T passes through the positioning detection unit 81.

Next, the image reading unit 12 will be described. The image reading unit 12 operates to read the color image formed on the document T, that is, the color image printed on the document T. The image reading unit 12 is provided with a one-dimensional image sensor 128. In addition to the image sensor 128, the image reading unit 12 includes a first platen glass 121, a second platen glass 122, a light source 123, mirrors 124, 125, 126, an imaging optical unit 127, and optics (not shown). It has a drive unit.

The light source 123 irradiates the document T with light. The optical drive unit (not shown) moves the document T or the image sensor 128 relatively in the sub-scanning direction. Here, the sub-scanning direction is a direction orthogonal to the main scanning direction when the arrangement direction of the plurality of light receiving elements constituting the image sensor 128 is the main scanning direction.

Therefore, the document T is conveyed by the automatic document feeder 14, and the image on one side or both sides of the document T is scanned and exposed by the optical system of the image reading unit 12. Next, the incident light reflecting the image reading operation is read by the image sensor 128. In the Plato mode, the image sensor 128 outputs the RGB color system image reading signal Sout obtained by reading the document T. Here, the Plato mode is printed on a document T placed on a platen glass such as the first platen glass 121 and the second platen glass 122 by driving an optical drive unit (not shown). This is an operation that automatically reads an image.

Next, the image sensor 128 will be specifically described. As the image sensor 128, a 3-line color CCD imaging device is used. The image sensor 128 is configured by arranging a plurality of light receiving element rows in the main scanning direction. Specifically, the red (R) color, green (G) color, and blue (B) color light detection reading sensors divide the pixels at different positions in the sub-scanning direction orthogonal to the main scanning direction. Then, the light information of each of the R color, the G color, and the B color is read at the same time. For example, in the automatic paper feed mode, when the document T is inverted in a U shape by the roller 143, the image sensor 128 reads the surface of the document T and outputs an image reading signal Sout.

More specifically, the image sensor 128 photoelectrically converts the incident light and is connected to the image processing unit 43 via the control unit 41. The analog image reading signal Sout photoelectrically converted by the image sensor 128 is subjected to analog processing, A / D conversion, shading correction, image compression processing, scaling processing, and the like in the image processing unit 43. As a result, the image reading signal Sout becomes digital image data including the R color component, the G color component, and the B color component. The image processing unit 43 uses a three-dimensional color information conversion table to convert the image data, that is, the RGB code, into Y (yellow), M (magenta), C (cyan), and K (black) color image data, that is, , Dy, Dm, Dc, Dk. The image processing unit 43 transfers the converted image data to the LED writing units 611Y, 611M, 611C, and 611K included in the image forming unit 60.

Next, the details of the image forming unit 60 will be described. The image forming unit 60 uses an electrophotographic process technique to form a color image of an intermediate transfer method. The image forming unit 60 adopts a vertical tandem system.

Specifically, the image forming unit 60 forms a color image based on the image data transferred from the image processing unit 43, that is, Dy, Dm, Dc, and Dk. The image forming unit 60 includes an image forming unit 601Y, 601M, 601C, 601K for each color, an intermediate transfer unit 620, and a fixing unit 630 for fixing a toner image.

Next, the image forming unit 601Y will be described. The image forming unit 601Y forms a Y (yellow) color image. The image forming unit 601Y includes a photosensitive drum 613Y, a charging unit 614Y, an LED writing unit 611Y, a developing unit 612Y, and a cleaning unit 616Y.

The photosensitive drum 613Y forms a Y-color toner image. The charging portion 614Y is arranged around the photosensitive drum 613Y, and uniformly charges the surface of the photosensitive drum 613Y to a negative electrode by corona discharge. The LED writing unit 611Y irradiates the photosensitive drum 613Y with light corresponding to the image of the Y color component. The developing unit 612Y visualizes the electrostatic latent image and forms the toner image by adhering the toner of the Y color component to the surface of the photosensitive drum 613Y. The cleaning unit 616Y removes the transfer residual toner remaining on the surface of the photosensitive drum 613Y after the primary transfer.

Since each of the image forming units 601M, 601C, and 601K has the same configuration and function as the image forming unit 601Y except that the colors of the images to be formed are different, the description thereof will be omitted.

When the image forming units 601Y, 601M, 601C, and 601K are collectively referred to, they are referred to as the image forming unit 601. Further, when the LED writing units 611Y, 611M, 611C, and 611K are collectively referred to, they are referred to as the LED writing unit 611. Further, when the developing units 612Y, 612M, 612C, and 612K are collectively referred to, they are referred to as the developing unit 612. Further, when the photosensitive drums 613Y, 613M, 613C, and 613K are collectively referred to, they are referred to as the photosensitive drum 613. Further, when the charging units 614Y, 614M, 614C, and 614K are collectively referred to, they are referred to as the charging unit 614. Further, when the cleaning units 616Y, 616M, 616C, and 616K are collectively referred to, they are referred to as the cleaning unit 616.

Next, the intermediate transfer unit 620 will be described. The intermediate transfer unit 620 includes an intermediate transfer belt 621, a primary transfer roller 622Y, 622M, 622C, 622K, a secondary transfer roller 623, a belt cleaning device 624, and the like.

The intermediate transfer belt 621 is composed of an endless belt, and is stretched in a loop by a plurality of support rollers. At least one of the plurality of support rollers is composed of a driving roller, and the other is composed of a driven roller. For example, it is preferable that the support roller arranged on the downstream side in the belt traveling direction with respect to the primary transfer roller 622K for the K component is the drive roller. As the drive roller rotates, the intermediate transfer belt 621 travels at a constant speed in the direction of arrow Z.

The primary transfer rollers 622Y, 622M, 622C, and 622K are arranged on the inner peripheral surface side of the intermediate transfer belt 621 so as to face the photosensitive drum 613 of each color component. The primary transfer rollers 622Y, 622M, 622C, and 622K are pressed against the photosensitive drums 613Y, 613M, 613C, and 613K with the intermediate transfer belt 621 sandwiched between them. As a result, a primary transfer nip for transferring the toner image from the photosensitive drums 613Y, 613M, 613C, and 613K to the intermediate transfer belt 621 is formed.

When the primary transfer rollers 622Y, 622M, 622C, and 622K are collectively referred to, they are referred to as the primary transfer roller 622.

The secondary transfer roller 623 is arranged on the outer peripheral surface side of the intermediate transfer belt 621 so as to face one of the plurality of support rollers. The support roller arranged to face the intermediate transfer belt 621 is called a backup roller. By pressing the secondary transfer roller 623 against the backup roller with the intermediate transfer belt 621 sandwiched between them, a secondary transfer nip for transferring the toner image from the intermediate transfer belt 621 to the paper P is formed.

When the intermediate transfer belt 621 passes through the primary transfer nip, the toner image on the photosensitive drum 613 is sequentially superimposed on the intermediate transfer belt 621 and first transferred. Specifically, a toner image is obtained by applying a primary transfer bias to the primary transfer roller 622 and applying a charge having the opposite polarity to the toner on the back surface side of the intermediate transfer belt 621, that is, the side in contact with the primary transfer roller 622. Is electrostatically transferred to the intermediate transfer belt 621.

After that, when the paper P passes through the secondary transfer nip, the toner image on the intermediate transfer belt 621 is secondarily transferred to the paper P. Specifically, a secondary transfer bias is applied to the secondary transfer roller 623 to apply a charge having a polarity opposite to that of the toner on the back surface side of the paper P, that is, the side in contact with the secondary transfer roller 623. The image is electrostatically transferred to the paper P. The paper P on which the toner image is transferred is conveyed toward the fixing portion 630.

The belt cleaning device 624 has a belt cleaning blade or the like that is in sliding contact with the surface of the intermediate transfer belt 621. The belt cleaning device 624 removes the transfer residual toner remaining on the surface of the intermediate transfer belt 621 after the secondary transfer.

In the intermediate transfer unit 620, instead of the secondary transfer roller 623, a secondary transfer belt (not shown) is stretched in a loop on a plurality of support rollers including the secondary transfer roller 623, a so-called belt. The secondary transfer unit of the formula may be adopted.

Next, the fixing portion 630 will be described. The fixing unit 630 includes a heating roller 631, a pressure roller 632, a heating unit 633, and a temperature detection unit 83, and fixes the toner image transferred by the image forming unit 60 on the paper P.

Specifically, the heating unit 633 is provided inside the heating roller 631 and intermittently heats the heating roller 631. The pressurizing roller 632 is arranged to face the heating roller 631 and pressurizes the heating roller 631. The temperature detection unit 83 is provided around the heating roller 631 and detects the temperature of the heating roller 631. The sampling period of the temperature detection unit 83 is, for example, 100 ms.

In the fixing unit 630, the heating unit 633 heats the heating roller 631 according to the detection result of the temperature detecting unit 83 that detects the temperature of the heating roller 631. The fixing portion 630 forms a fixing nip between the heating roller 631 and the pressure roller 632 by pressing the heating roller 631 and the pressure roller 632 against each other.

The fixing unit 630 fixes the transferred toner image on the paper P through the action of the pressure by the pressure roller 632 and the heat of the heating roller 631. An image is printed on the paper P fixed by the fixing unit 630. The paper P on which the image is printed is discharged to the outside of the machine by the paper ejection roller 304, and is conveyed to, for example, the image reading device 7. The paper P on which the image is printed may be loaded on the output tray 305 without being conveyed to the image reading device 7.

Next, the paper feed unit 20 will be described. The paper feed unit 20 includes a paper feed cassette 200, a feed roller 201, and the like. The paper cassette 200 accommodates the paper P. The delivery roller 201 takes in the paper P stored in the paper feed cassette 200 and sends it out to the transport unit 30.

Next, the transport unit 30 will be described. The transport unit 30 has a transport path 300, and transports the paper P according to the transport path 300. The transport path 300 includes a paper feed roller 302A, a transport roller 302B, 302C, 302D, a resist roller 303, and the like.

The transport path 300 transports the paper P fed from the paper feed unit 20 to the image forming unit 60. When the image is formed on the back surface of the paper P as well, after the image is formed on the front surface of the paper P, the paper P is recirculated by the branching portion 306 through the circulation paper passage 307A, the reverse transfer passage 307B, and the re-formation. The paper is conveyed in the order of the paper feed transfer path 307C.

Next, the control system will be described. The image forming apparatus 5 executes various processes via the control unit 41. For example, the image reading signal Sout output from the image reading unit 12 is transmitted to an image memory or an image processing unit 43 (not shown) via the control unit 41. The image memory includes, for example, a hard disk or the like.

Specifically, the control unit 41 is mainly composed of a CPU, ROM, RAM, and an I / O interface (not shown). The control unit 41 reads various programs according to the processing contents from the ROM or a storage unit (not shown), expands them in the RAM, and cooperates with the expanded various programs to operate each unit of the image forming apparatus 5. Control.

That is, the control unit 41 controls the operation of the image forming apparatus 5, and can be realized by a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown). Various functions are realized when the control unit 41 executes a predetermined control program.

Next, the image reading device 7 will be specifically described. FIG. 3 is a diagram showing a configuration example of the image reading device 7 according to the first embodiment of the present invention. FIG. 4 is a diagram showing a functional configuration example of the control unit 51 according to the first embodiment of the present invention.

The image reading device 7 is arranged on the downstream side of the image forming device 5 and reads an image printed on one side or both sides of the paper P. The image reading device 7 obtains an image correction amount based on the reading result such as the color, position, and magnification of the image printed on the paper P, and feeds back the obtained image correction amount to the image forming device 5.

The image reading device 7 includes a control unit 51, a first scanner 701a, a second scanner 701b, a colorimeter 703, calibration units 705a to 705c, a transfer roller 731, and a transfer path 700. The transport path 700 is a path through which the paper P supplied from the image forming apparatus 5 is passed, and the paper P is transported by driving the transport roller 731.

When the image reading device 7 receives the paper P supplied from the image forming apparatus 5, for example, the image reading device 7 causes the first scanner 701a, the second scanner 701b, or the colorimeter 703 to detect the image formed on the paper P. The image detection result is output to the control unit 51 of the image reading device 7.

The control unit 51 controls the operation of the image reading device 7, and can be realized by a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown). When the control unit 41 executes a predetermined control program, as shown in FIG. 4, various functions including the position adjustment unit 511, the monitoring unit 513, and the machine difference adjustment unit 515 are realized. The control unit 51 executes various processes based on the image detection result, and transmits the execution result to the control unit 41 of the image forming apparatus 5.

The position adjusting unit 511 adjusts the front and back positions of the mark A based on the print position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. Here, the mark A formed on the paper P will be described.

FIG. 5 is a diagram showing an example of a mark A formed on the paper P according to the first embodiment of the present invention. As shown in FIG. 5, the mark A is a crosshair and is used for detecting the misalignment of the front and back surfaces. The mark A is formed at a position T1 away from the corner of the paper P in each of the vertical and horizontal directions. Since the paper P has four corners, four marks A are also formed, but it is not necessary that the paper P is formed at all the corners, as long as the front and back misalignment can be detected by the marks A. Further, the mark A does not have to be a crosshair.

Return to FIG. The monitoring unit 513 monitors the front / back position deviation of the mark A based on the front / back position of the mark A adjusted by the position adjusting unit 511. The machine difference adjusting unit 515 sets the first scanner 701a and the second scanner 701b based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. Adjust the machine difference.

When the machine difference adjusting unit 515 adjusts the machine difference between the first scanner 701a and the second scanner 701b, the position adjusting unit 511 is a reference for monitoring the front and back misalignment of the mark A by the monitoring unit 513. Determine the adjustment reference position.

The first scanner 701a and the second scanner 701b are respectively arranged so as to face the paper P passing through the transport path 700, and read the image printed on the paper P. The first scanner 701a reads the back surface of the paper P, and the reading result is used, for example, for checking the deviation between the front and back sides of the image printed on the paper P, checking for the presence or absence of an unexpected image, and the like. On the other hand, the second scanner 701b reads the surface of the paper P, and reads an image printed on the paper P, for example, a patch (not shown). When the first scanner 701a and the second scanner 701b are not particularly distinguished, they are referred to as scanners 701.

The image reading device 7 is operated by either an in-line method or an offline method.

The in-line method is configured to directly feed the image-formed paper P supplied from the image-forming device 5 to the image reading device 7. On the other hand, the offline method is not configured to directly feed the image-formed paper P supplied from the image forming device 5 to the image reading device 7, but the image forming device 5 and the image reading device 7 Is a method configured independently of each other. Here, the following description will be given on the premise of the inline method, but the offline method may be used.

The colorimeter 703 is located on the downstream side of the scanner 701 and is arranged at a position facing the paper P through which the transport path 700 is passed. The colorimeter 703 guarantees the absolute value of the color of the image formed on the paper P, for example, by measuring the color of the patch among the images formed on the paper P.

Specifically, the colorimeter 703 irradiates visible light toward the patch from a visible light source (not shown), acquires the spectral spectrum of the reflected light of visible light reflected by the calibration unit 705c, and acquires the spectrum. Based on the spectrum, an operation on a predetermined color system is executed, and the tint of the patch is derived.

The color measurement result of the patch is generated as numerical data represented by a predetermined color system, for example, Lab color space data or XYZ color space data, that is, a color measurement value, and is output to the control unit 51 or the control unit 41. NS.

The color measurement range of the colorimeter 703, that is, the viewing angle is set to be narrower than the reading range of the scanner 701 and narrower than the patch width along the paper width direction. Specifically, the lens portion that acquires the reflected light of the patch is, for example, about 4 mm.

As described above, since the colorimeter 703 measures colors only within a certain viewing angle range, it can reproduce color information with higher accuracy than the scanner 701.

The control unit 51 corrects the color information of the patch read by the scanner 701 based on the color measurement value of the patch measured by the colorimeter 703. Specifically, the control unit 51 associates the color information of the patch measured by the colorimeter 703 with the color information of the patch read by the scanner 701. If the color information of the patch by the colorimeter 703 and the color information of the patch by the scanner 701 are associated with each other, the color measurement result of the colorimeter 703 can be reflected in the reading result of the scanner 701, which is accurate. The amount of correction is obtained.

The image processing unit 43 optimizes the image to be formed by the image forming unit 60 based on the correction amount calculated by the control unit 51. The image optimization process executed by the image processing unit 43 includes front / back position adjustment, density adjustment, color tone adjustment, and the like of the image to be printed on the paper P.

That is, the image processing unit 43 corrects the color, position, or magnification of the image formed on the paper P according to the reading result of the paper P of the image reading device 7. Specifically, the image processing unit 43 corrects the image formed on the paper P based on the corrected color information. The image processing unit 43 issues a command to the image forming unit 60 to form an image on the paper P based on the correction result.

The calibration units 705a and 705b are arranged at positions facing the scanner 701 and reflect the irradiation light emitted to the paper P when the image is read.

Next, the transport path 700 will be specifically described. FIG. 6 is a diagram showing an example in which the same paper P is transported in the transport path 700 of the paper P according to the first embodiment of the present invention. As shown in FIG. 6, an inversion path 751a is provided between the first scanner 701a and the second scanner 701b along the transport path 700. The reversing path 751a reverses the paper P read by the first scanner 701a on the upstream side and conveys it to the second scanner 701b on the downstream side.

Therefore, if the paper P passes through the reversal path 751a, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the first surface P_1f of the paper P.

Therefore, in the transport path 700 of FIG. 6, the first scanner 701a and the second scanner 701b can read the mark A formed on the same surface of the same paper P.

Further, if the paper P does not pass through the reversal path 751a, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the second surface P_2f of the paper P.

Therefore, in the transport path 700 of FIG. 6, the first scanner 701a and the second scanner 701b can read the marks A formed on different surfaces of the paper P.

The first surface P_1f of the paper P means either the front surface or the back surface of the paper P, and the second surface P_2f of the paper P is any of the front surface and the back surface of the paper P. Or the other. The same shall apply in the following description.

In the transport path 700 of FIG. 6, the machine difference adjusting unit 515 adjusts the machine difference of each scanner 701 based on the mark A formed on the same surface of the paper P. Further, in the transport path 700 of FIG. 6, when the monitoring unit 513 monitors the front-back position deviation of the mark A formed on the paper P, the paper among the adjustment reference positions of the mark A determined by the position adjusting unit 511. The first adjustment reference of the first adjustment reference position of the mark A formed on the first surface P_1f of P and the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a. Monitor the amount of deviation. Further, in the transport path 700 of FIG. 6, when the monitoring unit 513 monitors the front-back position deviation of the mark A formed on the paper P, the paper among the adjustment reference positions of the mark A determined by the position adjusting unit 511. The second adjustment reference position of the mark A formed on the second surface P_2f of P and the printing position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b. Monitor the amount of deviation.

Further, in the transport path 700 of FIG. 6, the position adjusting unit 511 marks A based on the first adjustment reference deviation amount monitored by the monitoring unit 513 and the second adjustment reference deviation amount monitored by the monitoring unit 513. Adjust the front and back positions of.

The adjustment of the front and back positions of the mark A may result in the adjustment of the front and back positions of the mark A, and the specific adjustment process is not limited. For example, the reading time of each scanner 701 may be adjusted, and the correction amount based on the adjustment result may be fed back to the image forming apparatus 5. Further, for example, the correction amount based on the reading result of each scanner 701 is fed back to the image forming apparatus 5, and the image forming apparatus 5 actually adjusts the printing position of the mark A when forming the mark A on the paper P. You may.

Next, a control example of the control unit 51 in the transport path 700 of FIG. 6 will be described. FIG. 7 is a flowchart illustrating a control example according to the first embodiment of the present invention.

In step S11, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S12, the second scanner 701b reads the mark A formed on the first surface P_1f of the paper P. In step S13, the difference between the first scanner 701a and the second scanner 701b is adjusted.

As described above, the process of steps S11 to S13 is the machine difference adjustment process.

In step S14, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S15, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S16, the adjustment reference position is determined based on the printing position of the mark A formed on the first surface P_1f of the paper P and the printing position of the mark A formed on the second surface P_1f of the paper P.

As described above, the processes of steps S14 to S16 are processes for determining the adjustment reference position to be performed when monitoring the front / back position deviation of the paper P.

In step S17, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S18, it is determined whether or not there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions. If it is determined that there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions, the process proceeds to step S19, and in step S19. , The deviation of the first surface P_1f is adjusted, and the process proceeds to step S20. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions, the process proceeds to step S20.

In step S20, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S21, it is determined whether or not there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions. If it is determined that there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions, the process proceeds to step S22, and in step S22. , The deviation of the second surface P_2f is adjusted, and the process proceeds to step S23. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions, the process proceeds to step S23.

In step S23, it is determined whether or not the monitoring is terminated. When it is determined that the monitoring is terminated, the process is terminated. On the other hand, if it is determined that the monitoring is not completed, the process returns to step S17.

As described above, the processes of steps S17 to S23 are the monitoring process and the position adjustment process.

It should be noted that there are conditions that affect the occurrence of front and back misalignment of printing. The first is the environmental condition, which is the temperature and humidity of the printing place. Specifically, there are a hot and humid environment, a low temperature and low humidity environment, and a general environment. In a hot and humid environment, the water content of the paper P tends to increase, and the printing position tends to shift. In a low temperature and low humidity environment, the paper P tends to slip and the printing position tends to shift. In a general environment, the paper P is stable and the printing position shift is unlikely to occur.

In the following description, a high temperature and high humidity environment will be referred to as an HH environment, a low temperature and low humidity environment will be referred to as an LL environment, and a general environment will be referred to as an NN environment.

The second is paper P for printing. Paper P includes high basis weight paper, large size paper, thick paper, and the like. The high basis weight paper is a paper having a large basis weight, and is often thick paper P, the water content is liable to change, and the printing position is liable to shift. Since the printed image is large on large-sized paper, the printing position is likely to shift due to the printing magnification. Thick paper is thick for its basis weight, and the water content is liable to change, and the printing position is liable to shift.

The third is deterioration of mechanical durability of the printing machine body. For example, if each part of the image forming apparatus 5 is mechanically deteriorated by long-term use, the printing position shift is likely to occur.

In addition, the monitoring period of the front and back positions is set by the environmental conditions or the user. For example, when printing in an HH environment or an LL environment, or printing on thick paper P, it is preferable to monitor each part every time it is printed. In other words, it is a case where it is presumed that sudden front-back misalignment is likely to occur in short-term monitoring.

Further, for example, when the machine wear of the printing machine body becomes severe, it is preferable to monitor it every 6 hours. In other words, it is a case where it is presumed that there is a possibility that a sudden front-back misalignment may occur in the monitoring for a medium period.

Further, for example, when printing in an NN environment or printing on standard recommended paper, it is preferable to monitor once a day in the morning. That is, it is a case where it is presumed that sudden front-back misalignment is unlikely to occur in long-term monitoring.

Next, the machine difference adjustment and the front and back misalignment adjustment will be specifically described. FIG. 8 is a diagram showing an example of adjusting the front and back positions of the mark A in the first embodiment of the present invention. The 0th sheet of FIG. 8 corresponds to the paper P for adjusting the machine difference performed before monitoring, and the first and subsequent sheets correspond to the paper P for monitoring performed after adjusting the machine difference.

Specifically, on the 0th sheet, the machine difference adjustment of each scanner 701 is performed before monitoring the front and back misalignment of the mark A formed on the paper P. For example, the print position of the mark A on the first surface P_1f read by the second scanner 701b is adjusted according to the print position of the mark A read by the first scanner 701a.

Further, in the first sheet, a process of determining an adjustment reference position for use in monitoring is performed. On the second and subsequent sheets, the front and back misalignment of the mark A is monitored based on the adjustment reference position determined on the first sheet. For example, on the nth sheet, the print position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted according to the second adjustment reference position determined on the first sheet.

Even if the print position of the mark A matches the design value, when the adjustment reference position is determined on the first sheet, it is adjusted so as not to be different from the adjustment reference position determined on the first sheet.

In the case of the reversing path 751a provided in the transport path 700 of FIG. 6, the same paper P was read by each scanner 701, but the present invention is not limited to this. FIG. 9 is a diagram showing an example in which different papers P are transported in the paper P transport path 700 according to the first embodiment of the present invention.

In the transport path 700 of FIG. 9, an inversion path 751b is provided on the upstream side of the first scanner 701a. Therefore, in the inversion path 751b of FIG. 9, the first scanner 701a is made to read the paper P'with the first surface P'_1f faced up, and the second scanner 701b is made to read the paper with the first surface P_1f faced down. P can be read. As a result, the inversion path 751b in FIG. 9 allows each scanner 701 to read the same side of different sheets P and P', that is, the first side P_1f and the first side P'_1f. When any of the inversion paths 751a and 751b is not distinguished, it is referred to as an inversion path 751.

As described above, the image reading device 7 adjusts the front and back positions of the marks A based on the printing positions of the marks A formed on the front and back of the paper P read by at least one of the first scanner 701a and the second scanner 701b. ..

For example, if the front and back positions of the mark A are adjusted based on the print position of the mark A read by the first scanner 701a, the front and back position deviation of the mark A due to the first scanner 701a alone is adjusted. Further, for example, if the front and back positions of the mark A are adjusted based on the print position of the mark A read by the second scanner 701b, the front and back position deviation of the mark A due to the second scanner 701b alone is adjusted. .. Further, for example, if the front and back positions of the mark A are adjusted based on the print position of the mark A read by each of the first scanner 701a and the second scanner 701b, the mark A may be caused by the difference between the scanners 701. The front and back misalignment is adjusted.

Further, the image reading device 7 monitors the front / back position deviation of the mark A based on the adjusted front / back position of the mark A. For example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the reading result of the first scanner 701a, even if there is a machine difference between the first scanner 701a and the second scanner 701b, there is a machine difference. The front and back misalignment of the mark A can be monitored without any influence.

Further, for example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the reading result of the second scanner 701b, even if there is a difference between the second scanner 701b and the first scanner 701a, the machine The front and back misalignment of the mark A can be monitored without being affected by the difference.

Further, for example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the reading results of the first scanner 701a and the second scanner 701b, the difference between the first scanner 701a and the second scanner 701b. It is possible to monitor the front and back misalignment of the mark A in the state where is adjusted.

In any case, the influence of the difference between the scanners 701 can be eliminated without making mechanical adjustments.

Further, since the front-back position shift of the mark A can be detected, the front-back position shift of the image formed with the mark A as a reference can be detected. The front-back position shift of the mark A can be easily detected without being overlooked because the detection target is simpler and limited as compared with the case where only the front-back position shift of the image is detected. Therefore, it is possible to easily detect a sudden front-back position shift of the image.

In other words, the image reading device 7 determines the front and back positions of the mark A based on the printing positions of the marks A formed on the front and back of the paper P read by at least one of the first scanner 701a and the second scanner 701b. By adjusting and monitoring the front-back position deviation of the mark A based on the adjusted front-back position of the mark A, the influence of the machine difference of each scanner 701 can be eliminated without mechanical adjustment, and the mark can be eliminated. Since the front-back misalignment of A can be detected, the sudden front-back misalignment of the image can be easily detected while accurately reading the front-back position of the image formed on the paper P at low cost.

Further, in the image reading device 7, the first scanner 701a and the second scanner 701b are based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. When the difference between the two scanners is adjusted, the adjustment reference position of the mark A, which is the reference for monitoring the front and back misalignment of the mark A, is determined, so that the adjustment reference position of the mark A is adjusted by the machine difference of each scanner 701. Since it serves as a reference for the state of being used, it is possible to monitor the front-back misalignment of the mark A by using both the first scanner 701a and the second scanner 701b. Therefore, since the marks A formed on the front and back sides of the paper P can be monitored at the same time in one transfer, if there is a misalignment between the front and back sides of the marks A, the marks are compared with the case where one scanner 701 transports the marks twice. The time required to detect the front-back misalignment of A can be shortened.

Further, in the image reading device 7, the marks A read by each scanner 701 are formed on the same surface by adjusting the machine difference of each scanner 701 based on the marks A formed on the same surface of the paper P. Therefore, the same comparison target is compared, and the difference between the scanners 701 can be accurately detected.

Further, in the image reading device 7, the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the adjustment reference of the mark A formed on the first surface P_1f of the paper P. The amount of deviation from the first adjustment reference with respect to the position was monitored, and the printing position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the printing position of the mark A formed on the second surface P_2f of the paper P were formed. The amount of the second adjustment reference deviation from the adjustment reference position of the mark A is monitored, and the front and back positions of the mark A are adjusted based on the first adjustment reference deviation amount and the second adjustment reference deviation amount.

Therefore, since the front and back positions of the mark A are adjusted based on the relative front and back position shifts of the mark A, the front and back position shifts of the mark A can be monitored at low cost.

As described above, according to the present embodiment, it is possible to monitor the front-back positional deviation of the mark A without being affected by the machine difference of each scanner 701. Therefore, the high-precision component accuracy and the high-precision mounting position accuracy required for mechanically adjusting the component accuracy, the mounting position accuracy, and the like are not required. Therefore, the image forming system 1 can be formed at low cost.

The machine difference of each scanner 701 is caused by various factors such as individual lens difference, lens mounting position variation, scanner 701 mounting position variation, and the like. In particular, the individual lens difference is based on the lens strain, and the magnification or the partial magnification in the reading main scanning direction deviates. Therefore, enabling the detection of the front-back positional deviation of the mark A without being affected by the machine difference of each scanner 701 contributes to a significant cost reduction of the entire system when constructing the image forming system 1. Become.

Further, as the image forming apparatus 5 prints on both sides, even though the print setting is not changed, the front and back position shift of the mark A or the image position shift due to the front and back position shift of the mark A occurs. There is. Such deviation is sudden because it occurs due to environmental conditions such as temperature and humidity of the printing place or deterioration of machine durability. Therefore, conventionally, the front and back positions of the mark A are measured at regular intervals, but side effects also occur due to the frequency of measuring the front and back positions of the mark A.

For example, if the front / back position measurement frequency of the mark A is increased, the front / back position deviation of the mark A is detected at an early stage, but it takes a lot of time, so that the productivity of the entire system is lowered. On the other hand, if the front-back position measurement frequency of the mark A is reduced, it is possible to devote more time to production, but there is a risk that the front-back position deviation of the mark A cannot be detected, and the front-back position deviation of the mark A cannot be detected for printing. The output is wasted, which causes an increase in cost.

Therefore, if the front-back misalignment of the mark A is monitored as in the present embodiment, the sudden front-back misalignment of the mark A due to a change in environmental conditions can be easily detected, and the cost of the entire system can be reduced. Can be made to.

In other words, the image forming system 1 includes the image reading device 7 and the image forming device 5, so that the front and back positions of the image formed on the paper P can be set at low cost as in the case of the image reading device 7. It is possible to easily detect a sudden front-back misalignment of an image while reading it accurately.

Further, since the image forming system 1 can easily detect the front-back positional deviation of the output object of the image forming apparatus 5 at low cost by the image reading device 7, it is possible to provide a low-cost feedback system as a whole system.

In this way, according to the image reading device 7 according to the present embodiment, the image forming device 5 forms marks A on the front and back surfaces of the paper P, respectively, and the first scanner 701a and the first scanner 701a that read the marks A. An image reading device 7 provided on the downstream side of the screen and provided with a second scanner 701b for reading the mark A, at the printing position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. Based on this, it includes a position adjusting unit 511 that adjusts the front and back positions of the mark A, and a monitoring unit 513 that monitors the front and back position deviation of the mark A based on the front and back positions of the mark A adjusted by the position adjusting unit 511. Is.

As a result, it is possible to accurately read the front and back positions of the image formed on the paper P at low cost, and easily detect a sudden front and back position shift of the image.

Further, according to the image reading device 7 according to the present embodiment, the first scanner is based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. The machine difference adjusting unit 515 for adjusting the machine difference between the 701a and the second scanner 701b is further provided, and the position adjusting unit 511 is the front and back of the mark A by the monitoring unit 513 when the machine difference is adjusted by the machine difference adjusting unit 515. The adjustment reference position of the mark A, which is the reference for monitoring the misalignment, is determined.

As a result, if there is a front-back misalignment of the mark A, the image reading device 7 can shorten the time required to detect the front-back misalignment of the mark A as compared with the case where one scanner 701 conveys the image twice. can.

Further, according to the image reading device 7 according to the present embodiment, the machine difference adjusting unit 515 adjusts the machine difference based on the mark A formed on the same surface of the paper P.

As a result, the image reading device 7 can accurately detect the difference between the scanners 701.

Further, according to the image reading device 7 according to the present embodiment, the monitoring unit 513 monitors the front and back misalignment of the mark A formed on the paper P, and the adjustment reference of the mark A determined by the position adjusting unit 511. Of the positions, the first adjustment reference position of the mark A formed on the first surface P_1f of the paper P and the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a. The second adjustment reference position of the mark A formed on the second surface P_2f of the paper P among the adjustment reference positions of the mark A determined by the position adjustment unit 511 while monitoring the first adjustment reference deviation amount of The second adjustment reference deviation amount from the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b is monitored, and the position adjustment unit 511 is monitored by the monitoring unit 513. The front and back positions of the mark A are adjusted based on the 1 adjustment reference deviation amount and the second adjustment reference deviation amount monitored by the monitoring unit 513.

As a result, the image reading device 7 can monitor the front and back misalignment of the mark A at low cost.

Further, according to the image forming system 1 according to the present embodiment, the image reading device 7 described above and the image forming device 5 for forming an image on the paper P are provided.

As a result, the image forming system 1 can easily detect sudden front and back misalignment of the image while accurately reading the front and back positions of the image formed on the paper P at low cost, as in the case of the image reading device 7. can do.

Further, the image forming system 1 can provide a low-cost feedback system as a whole system.

Further, according to the program according to the present embodiment, the image forming apparatus 5 forms marks A on the front and back surfaces of the paper P, respectively, and is provided on the downstream side of the first scanner 701a and the first scanner 701a for reading the marks A. , A computer that controls an image reading device 7 including a second scanner 701b that reads the mark A, based on the printing position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. It functions as a position adjusting unit 511 that adjusts the front and back positions of the mark A and a monitoring unit 513 that monitors the front and back position deviation of the mark A based on the front and back positions of the mark A adjusted by the position adjusting unit 511.

As a result, the program can easily detect a sudden front-back position shift of the image while accurately reading the front-back position of the image formed on the paper P at low cost, as in the case of the image reading device 7. can.

Embodiment 2.
In the second embodiment, the same reference numerals are added to the same configurations as those in the first embodiment, and the description thereof will be omitted. In the second embodiment, the machine difference of each scanner 701 is adjusted by using the master manuscript, and the front and back misalignment of the mark A on the paper P is monitored by using the mark A formed on the master manuscript as a design standard.

FIG. 10 is a diagram showing an example of a paper P transport path 700 according to the second embodiment of the present invention. As shown in FIG. 10, a first scanner 701a and a second scanner 701b are provided along the transport path 700. Therefore, in the transport path 700 of FIG. 10, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the second surface P_2f of the paper P.

In the transport path 700 of FIG. 10, when the machine difference of each scanner 701 is adjusted, the master original is used as the paper P. In the master document, the printing position of the mark A formed on the first surface P_1f and the printing position of the mark A formed on the second surface P_1f are formed at the same position in the front and back penetrating directions of the paper P. Is.

Further, in the transport path 700 of FIG. 10, the machine difference adjusting unit 515 is read by the printing position of the mark A formed on the first surface P_1f of the master document read by the first scanner 701a and by the second scanner 701b. The machine difference of each scanner 701 is adjusted based on the printing position of the mark A formed on the second surface P_2f of the master document.

Further, in the transport path 700 of FIG. 10, when the machine difference of each scanner 701 is adjusted by the machine difference adjusting unit 515 by the machine difference adjusting unit 515, the position adjusting unit 511 uses the master document as the adjustment reference position of the mark A. The printed position of the formed mark A is set to the design reference position of the mark A.

Further, in the transport path 700 of FIG. 10, the monitoring unit 513 is formed on the first surface P_1f of the paper P read by the first scanner 701a when monitoring the front-back positional deviation of the mark A formed on the paper P. The first design reference position of the print position of the mark A and the first design reference position of the mark A formed on the first surface P_1f of the master document among the design reference positions of the mark A set by the position adjustment unit 511. Monitor the amount of deviation.

Further, in the transport path 700 of FIG. 10, the monitoring unit 513 is formed on the second surface P_2f of the paper P read by the second scanner 701b when monitoring the front-back positional deviation of the mark A formed on the paper P. The second design reference position of the print position of the mark A and the second design reference position of the mark A formed on the second surface P_2f of the master document among the design reference positions of the mark A set by the position adjustment unit 511. Monitor the amount of deviation.

Further, in the transport path 700 of FIG. 10, the position adjusting unit 511 is marked A based on the first design reference deviation amount monitored by the monitoring unit 513 and the second design reference deviation amount monitored by the monitoring unit 513. Adjust the front and back positions of.

Next, a control example of the control unit 51 in the transport path 700 of FIG. 10 will be described. FIG. 10 is a diagram showing an example of a paper P transport path 700 according to the second embodiment of the present invention.

In step S41, the first scanner 701a reads the mark A formed on the first surface P_1f of the master document. In step S42, the second scanner 701b reads the mark A formed on the second surface P_2f of the master document. In step S43, the difference between the first scanner 701a and the second scanner 701b is adjusted.

As described above, the processing of steps S41 to S43 is the machine difference adjustment processing.

In step S44, the mark A formed on the master document is set at the design reference position.

The process of step S44 is a process of determining the design reference position to be performed when monitoring the front / back position deviation of the paper P.

In step S45, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S46, it is determined whether or not there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions. If it is determined that there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions, the process proceeds to step S47, and in step S47. , The deviation of the first surface P_1f is adjusted, and the process proceeds to step S48. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions, the process proceeds to step S48.

In step S48, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S49, it is determined whether or not there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions. If it is determined that there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions, the process proceeds to step S50, and in step S50. , The deviation of the second surface P_2f is adjusted, and the process proceeds to step S51. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions, the process proceeds to step S51.

In step S51, it is determined whether or not the monitoring is terminated. When it is determined that the monitoring is terminated, the process is terminated. On the other hand, if it is determined that the monitoring is not completed, the process returns to step S45.

As described above, the processes of steps S45 to S51 are the monitoring process and the position adjustment process.

Next, the machine difference adjustment and the front and back misalignment adjustment will be specifically described. FIG. 12 is a diagram showing an example of adjusting the front and back positions of the mark A in the second embodiment of the present invention. The 0th sheet of FIG. 12 corresponds to the master manuscript for adjusting the machine difference performed before monitoring, and the first and subsequent sheets correspond to the paper P for monitoring performed after adjusting the machine difference.

Specifically, on the 0th sheet, the machine difference adjustment of each scanner 701 is performed before monitoring the front-back positional deviation of the mark A formed on the master document. For example, the print position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted according to the print position of the mark A on the second surface P_2f of the master document. Further, before the first image for monitoring is read by each scanner 701, a process for setting a design reference position for use in monitoring is performed.

Further, in the first and subsequent sheets, the front and back misalignment of the mark A is monitored based on the design reference position set in front of the first sheet. For example, on the nth sheet, the print position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted according to the second design reference position set in front of the first sheet.

The design reference position for monitoring is set to the print position of the mark A formed on the master document, but is not limited to this. For example, when the machine difference is adjusted on the 0th sheet, it is adjusted according to the master document. Therefore, the design reference position for monitoring may be the printing position of the mark A whose machine difference is adjusted on the 0th sheet. ..

In the above description, an example of using the master manuscript has been described, but the master manuscript is not limited as long as it does not deviate like the master manuscript. That is, the manuscript T may be able to read the positional relationship from the front and back with the same reference.

Specifically, the document T may have a round hole or a square hole that penetrates from the front surface to the back surface of the document T. In this case, it is possible to read the same hole position from both the front surface and the back surface of the document T. Further, the document T may have front and back position marks marked by a special ink that penetrates from the front surface to the back surface of the document T or from the back surface to the front surface of the document T. Further, the document T may be a document T having a member that penetrates from the front surface to the back surface of the document T and does not hinder the passage of paper, for example, a stapler needle or the like.

As described above, in the image reading device 7, the machine difference of each scanner 701 is adjusted based on the mark A formed on the master document, and the mark A formed on the master document is set at the design reference position of the mark A.

Therefore, the machine difference of each scanner 701 is adjusted based on the absolute standard, and the front and back misalignment of the mark A formed on the paper P is monitored based on the absolute standard. Therefore, the machine difference of each scanner 701 and the front and back of the mark A are monitored. The position can be adjusted accurately.

Further, in the image reading device 7, the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the design standard of the mark A formed on the first surface P_1f of the master document. The amount of deviation from the first design reference with respect to the position was monitored, and the printing position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the printing position of the mark A formed on the second surface P_2f of the master document were formed. The amount of the second design reference deviation from the design reference position of the mark A is monitored, and the front and back positions of the mark A are adjusted based on the first design reference deviation amount and the second design reference deviation amount.

Therefore, since the front and back positions of the mark A are adjusted based on the absolute front and back position deviation of the mark A, the front and back position deviation of the mark A can be accurately monitored.

From the above description, according to the image reading device 7 according to the present embodiment, when the machine difference is adjusted, the master original is used as the paper P, and the mark A formed on the first surface P_1f of the master original is printed. The position and the printing position of the mark A formed on the second surface P_2f of the master document are formed at the same position in the front and back penetrating directions of the paper P, and the machine difference adjusting unit 515 is the first. The printing position of the mark A formed on the first surface P_1f of the master document read by the scanner 701a and the printing position of the mark A formed on the second surface P_1f of the master document read by the second scanner 701b. Based on this, the machine difference is adjusted, and when the machine difference is adjusted by the machine difference adjusting unit 515 using the master document, the position adjusting unit 511 uses the mark A formed on the master document as the adjustment reference position of the mark A. The printing position is set to the design reference position of the mark A.

As a result, the image reading device 7 can accurately adjust the difference between the scanners 701 and the front and back positions of the mark A.

Further, according to the image reading device 7 according to the present embodiment, the monitoring unit 513 monitors the front and back misalignment of the mark A formed on the paper P, and the first scanner 701a reads the first sheet P. The print position of the mark A formed on the surface P_1f and the first design reference position of the mark A formed on the first surface P_1f of the master document among the design reference positions of the mark A set by the position adjusting unit 511. While monitoring the amount of deviation from the first design standard, the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the design standard of the mark A set by the position adjusting unit 511. Of the positions, the second design reference deviation amount of the mark A formed on the second surface P_2f of the master document from the second design reference position is monitored, and the position adjusting unit 511 monitors the first design monitored by the monitoring unit 513. The front and back positions of the mark A are adjusted based on the reference deviation amount and the second design reference deviation amount monitored by the monitoring unit 513.

As a result, the image reading device 7 can accurately monitor the front-back positional deviation of the mark A.

Embodiment 3.
In the third embodiment, the same reference numerals are added to the same configurations as those of the first and second embodiments, and the description thereof will be omitted. In the third embodiment, the second scanner 701b monitors the front and back misalignment of the mark A with reference to the front and back positions of the mark A adjusted by the first scanner 701a.

FIG. 13 is a diagram showing an example in which different papers P are transported in the paper P transport path 700 according to the third embodiment of the present invention. In the transport path 700 of FIG. 13, an inversion path 751b is provided on the upstream side of the first scanner 701a. The reversing path 751b in FIG. 13 faces down the face-up paper P conveyed from the upstream side and conveys it to the first scanner 701a on the downstream side. Therefore, if the paper P passes through the reversal path 751b, the first scanner 701a can read the second surface P_1f of the paper P, and the second scanner 701b can read the first surface P_1f of the paper P. Further, if the paper P does not pass through the reversal path 751b, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the second surface P_2f of the paper P.

In the transport path 700 of FIG. 13, the position adjusting unit 511 has the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the paper P read by the first scanner 701a. The front and back positions of the mark A are adjusted based on the printing position of the mark A formed on the second surface P_2f of the above. Further, in the transport path 700 of FIG. 13, when the position adjusting unit 511 adjusts the front and back positions of the mark A, the position adjusting unit 511 determines the adjustment reference position of the mark A which is the reference for monitoring the front and back position deviation of the mark A by the monitoring unit 513. do.

Further, in the transport path 700 of FIG. 13, the second scanner 701b reads the mark A formed on the paper P when the front and back misalignment of the mark A is monitored by the monitoring unit 513. Further, in the transport path 700 of FIG. 13, when the monitoring unit 513 monitors the front-back position deviation of the mark A formed on the paper P, the adjustment reference position of the mark A determined by the position adjusting unit 511 and the second The amount of adjustment reference position deviation from the print position of the mark A read by the scanner 701b is monitored.

Further, in the transport path 700 of FIG. 13, the position adjusting unit 511 adjusts the front and back positions of the mark A based on the adjustment reference deviation amount monitored by the monitoring unit 513.

Next, a control example of the control unit 51 in the transport path 700 of FIG. 13 will be described. FIG. 14 is a flowchart illustrating a control example according to the third embodiment of the present invention.

In step S71, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S72, the first scanner 701a reads the mark A formed on the second surface P_2f of the paper P. In step S73, it is determined whether or not the front and back positions of the mark A have been adjusted. When it is determined that the front and back positions of the mark A have been adjusted, the process proceeds to step S75, and in step S75, the print position of the mark A formed on the first surface P_1f of the paper P and the print position of the mark A formed on the second surface P_1f of the paper P are formed. The adjustment reference position is determined based on the printed position of the marked mark A. On the other hand, when it is determined that the front and back positions of the mark A are not adjusted, in step S74, the print position of the mark A formed on the first surface P_1f of the paper P and the print position of the mark A formed on the second surface P_1f of the paper P are formed. The front and back positions of the mark A are adjusted based on the print position of the mark A, and the process returns to step S71.

As described above, the processes of steps S71 to S75 are processes for determining the adjustment reference position to be performed when monitoring the front / back position deviation of the paper P.

In step S76, the second scanner 701b reads the mark A formed on the first surface P_1f of the paper P. In step S77, it is determined whether or not there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions. If it is determined that there is a discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions, the process proceeds to step S78, and in step S78. , The deviation of the first surface P_1f is adjusted, and the process proceeds to step S79. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions, the process proceeds to step S79.

In step S79, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S80, it is determined whether or not there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions. If it is determined that there is a discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions, the process proceeds to step S81, and in step S81. , The deviation of the second surface P_2f is adjusted, and the process proceeds to step S82. On the other hand, if it is determined that there is no discrepancy between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions, the process proceeds to step S82.

In step S82, it is determined whether or not the monitoring is terminated. When it is determined that the monitoring is terminated, the process is terminated. On the other hand, if it is determined that the monitoring is not completed, the process returns to step S76.

As described above, the processes of steps S76 to S83 are the monitoring process and the position adjustment process.

Next, the front-back misalignment adjustment will be specifically described. FIG. 15 is a diagram showing an example of adjusting the front and back positions of the mark A in the third embodiment of the present invention. The 0th front and back of FIG. 15 is performed before monitoring, and the paper P for adjusting the front and back positions corresponds to it, and only the reading result of the first scanner 701a is used. From the first time on the front and back of FIG. 15, the monitoring paper P performed after adjusting the front and back positions corresponds, and only the reading result of the second scanner 701b is used.

Specifically, at the 0th front and back, the front and back positions are adjusted by the first scanner 701a, which is performed before monitoring the front and back misalignment of the mark A formed on the paper P. For example, the print position of the mark A on the second surface P_1f read by the first scanner 701a is adjusted according to the print position of the mark A on the first surface P_1f read by the first scanner 701a.

In addition, in the first front and back, a process of determining an adjustment reference position for use in monitoring is performed. From the second front and back, the front and back misalignment of the mark A is monitored based on the adjustment reference position determined in the first front and back. For example, on the nth sheet, the print position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted according to the second adjustment reference position determined on the first sheet.

Even if the print position of the mark A matches the design value, when the adjustment reference position is determined on the first sheet, it is adjusted so as not to be different from the adjustment reference position determined on the first sheet.

In the case of the reversing path 751b provided in the transport path 700 of FIG. 13, the front and back positions are adjusted by different sheets P, but the present invention is not limited to this. FIG. 16 is a diagram showing an example in which the same paper P is transported in the transport path 700 of the paper P according to the third embodiment of the present invention.

In the transport path 700 of FIG. 16, an inversion path 751a is provided between the first scanner 701a and the second scanner 701b. Therefore, the first scanner 701a can read the paper P which is face-up and conveyed. Further, the reversing path 751a can face down the paper P that is faced up and conveyed and convey it to the downstream side. Therefore, the inversion path 751a of FIG. 16 allows the first scanner 701a to read the first surface P_1f of the paper P for the first time and the second surface P_2f of the paper P for the second time. As a result, the inversion path 751a of FIG. 9 allows each scanner 701 to read different surfaces of the same paper P, that is, the first surface P_1f and the second surface P_2f.

As described above, in the image reading device 7, the printing position of the mark A formed on the first surface P_1f of the paper P and the printing position of the mark A formed on the second surface P_1f of the paper P are set by the first scanner 701a. Based on this, the front and back positions of the mark A are adjusted.

Further, in the image reading device 7, when the front and back positions of the mark A are adjusted by the first scanner 701a, the adjustment reference position of the mark A, which is the reference for the front and back position deviation of the mark A, is determined.

Therefore, since the front-back positional deviation of the mark A is monitored based on the reading result of the first scanner 701a, it is not necessary to adjust the machine difference of each scanner 701. Therefore, it is possible to monitor the front and back misalignment of the mark A without being affected by the machine difference of each scanner 701.

Further, in the image reading device 7, the amount of front / back misalignment of the mark A is monitored by the second scanner 701b, and the front / back misalignment of the mark A is adjusted based on the monitoring result.

Therefore, even if there is a difference between the second scanner 701b and the first scanner 701a, the second scanner 701b is relative to the adjustment reference position of the mark A determined based on the reading result of the first scanner 701a. Since it is sufficient to detect such a difference, it is possible to monitor the front and back misalignment of the mark A particularly remarkably without being affected by the machine difference of each scanner 701.

From the above description, according to the image reading device 7 according to the present embodiment, the position adjusting unit 511 determines the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a. When the front and back positions of the mark A are adjusted based on the print position of the mark A formed on the second surface P_2f of the paper P read by the first scanner 701a, the monitoring unit 513 monitors the front and back misalignment of the mark A. The adjustment reference position of the mark A, which is the reference of the above, is determined.

As a result, the front-back positional deviation of the mark A can be monitored without being affected by the machine difference of each scanner 701.

Further, according to the image reading device 7, the second scanner 701b reads the mark A formed on the paper P when the front and back misalignment of the mark A is monitored by the monitoring unit 513, and the monitoring unit 513 reads the mark A. When monitoring the front-back position deviation of the mark A formed on the surface, the adjustment reference deviation amount between the adjustment reference position of the mark A determined by the position adjustment unit 511 and the print position of the mark A read by the second scanner 701b. The position adjusting unit 511 adjusts the front and back positions of the mark A based on the adjustment reference deviation amount monitored by the monitoring unit 513.

As a result, the front-back positional deviation of the mark A can be monitored particularly remarkably without being affected by the machine difference of each scanner 701.

Although the image forming apparatus 5 and the image reading apparatus 7 according to the present invention have been described above based on the embodiments, the present invention is not limited to this, and modifications are made without departing from the spirit of the present invention. You may.

For example, in the present embodiment, an example of an arrangement configuration in which the paper P is horizontally conveyed and the colorimeter 703 and the calibration unit 705 are provided above and below the paper P has been described. It is not limited. For example, the paper P may be conveyed vertically, and the colorimeter 703 and the calibration unit 705 may be provided on the left and right sides of the paper P.

Further, an example in which the image reading signal Sout is determined by the RGB color system as digital image data (RGB code) including R color, G color, and B color components has been described, but the present invention is not limited to this, and L * a *. b * It may be determined by a different color system such as a color system.

1 Image forming system 3 Paper feeding device 5 Image forming device 7 Image reading device 8 Paper ejection device 9 Paper ejection tray 11 Image forming apparatus main body 12 Image reading unit 121 First platen glass 122 Second platen glass 123 Light sources 124 to 126 Mirror 127 Imaging Optical Unit 128 Image Sensor 14 Automatic Document Feeder 141 Document Placement Unit 142a, 142b, 143, 144 Roller 145 Reversing Unit 146 Paper Discharge Plate 20 Paper Feeding Unit 200 Paper Feed Cassette 201 Feeding Roller 30 Transporting Unit 300 Route 302A Paper Feed Roller 302B, 302C, 302D Transport Roller 303 Resist Roller 304 Paper Discharge Roller 305 Paper Discharge Tray 306 Branch 307A Circulation Passage 307B Reverse Transport Path 307C Refeed Transport Path 41 Control Unit 43 Image Processing Unit 51 Control 511 Position adjustment unit 513 Monitoring unit 515 Machine difference adjustment unit 60 Image formation unit 601,601Y, 601M, 601C, 601K Image formation unit 611,611Y, 611M, 611C, 611K LED writing unit 612,612Y, 612M, 612C, 612K Development section 613,613Y, 613M, 613C, 613K Photosensitive drum 614, 614Y, 614M, 614C, 614K Charging section 616, 616Y, 616M, 616C, 616K Cleaning section 620 Intermediate transfer section 621 Intermediate transfer belt 622, 622Y, 622M, 622C , 622K Primary transfer roller 623 Secondary transfer roller 624 Belt cleaning device 630 Fixing part 631 Heating roller 632 Pressurizing roller 633 Heating part 81 Positioning detector 83 Temperature detector 700 Transport path 701 Scanner 701a First scanner 701b Second scanner 703 Measurement Color meter 705, 705a to 705c Calibration section 731 Conveying rollers 751, 751a, 751b Inverted path P paper

The present invention relates to an image forming system .

The present invention has been made to solve a conventional problem, and an object of the present invention is to accurately read the front and back positions of an image formed on paper at low cost and to suddenly read the front and back positions of an image. An object of the present invention is to provide an image forming system capable of easily detecting a deviation.

In order to achieve the above object, the image forming system according to the present invention forms an image of the first mark on the first surface of the paper and forms an image of the second mark on the second surface opposite to the first surface. The image-forming unit, the transport unit that transports the paper image-formed on both sides by the image-forming portion along the transport path, and the first and second marks that are image-formed on the paper transported by the transport unit. of a first scanner for reading the first indicia is disposed on the side opposite to the first scanner relative to the conveyance path, wherein the first indicia are imaged sheet conveyed by the conveying unit and the second The second scanner that reads the second mark among the marks and the paper on which the first mark and the second mark are image-formed during continuous image formation over a plurality of sheets of paper are read by the first scanner. 1 mark monitor, the second indicia read in the previous SL second scanner comprising a monitoring unit for monitoring, those.
Further, it is preferable that the monitoring unit monitors the misalignment of the first mark read by the first scanner and monitors the misalignment of the second mark read by the second scanner.
Further, the position of the first mark read by the first scanner before the misalignment monitoring of the first mark by the monitoring unit is set as the first reference position, and before the misalignment monitoring of the second mark by the monitoring unit. It is preferable that the position of the second mark read by the second scanner is set as the second reference position.

Claims (17)

The first scanner that reads the image formed on the paper,
A second scanner provided on the downstream side of the first scanner and on the side opposite to the first scanner with a transport path for passing the paper, and reading an image formed on the paper.
It is an image reader equipped with
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or , The printing position of the mark formed on the first surface of the document that can read the positional relationship from the front and back with the same reference as read by the first scanner, and the second surface of the document read by the second scanner. A machine difference adjusting unit that adjusts the machine difference between the first scanner and the second scanner based on the printed position of the formed mark, and
When the machine difference is adjusted by the machine difference adjusting unit, the first reference position, which is the reference position of the mark formed on the first surface of the paper, and the reference of the mark formed on the second surface of the paper. A position adjustment unit that determines the second reference position, which is the position, and
The first reference deviation amount, which is the deviation amount between the first reference position determined by the position adjusting unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. The second reference deviation amount, which is the deviation amount between the second reference position determined by the position adjusting unit and the printing position of the mark formed on the second surface of the paper read by the second scanner. With a monitoring unit that monitors
To prepare
Image reader. The position adjusting unit
Further, for adjusting the printing position when a mark is formed on the paper based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. Give feedback to the image forming device,
The image reading device according to claim 1. The machine difference adjustment unit
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner. Adjusting the difference between the first scanner and the second scanner,
The image reading device according to claim 1 or 2. A reversing path for reversing the paper is provided between the first scanner and the second scanner, or on the upstream side of the first scanner.
When the machine difference is adjusted by the machine difference adjusting unit, the first scanner reads an image formed on paper that has not been reversed by the inversion path, and the second scanner is inverted by the inversion path. Read the image formed on the paper
The image reading device according to claim 3. The machine difference adjustment unit
The machine difference is adjusted based on the marks formed on the first surface of the same paper read by the first scanner and the second scanner.
The image reading device according to claim 3 or 4. The machine difference adjustment unit
The machine difference is adjusted based on the marks formed on the first surface of the different sheets read by the first scanner and the second scanner.
The image reading device according to claim 3 or 4. The machine difference adjustment unit
At the printing position of the mark formed on the first surface of the original document read by the first scanner and the printing position of the mark formed on the second surface of the original document read by the second scanner. Based on this, the difference between the first scanner and the second scanner is adjusted.
The image reading device according to claim 1 or 2. The position adjusting unit
When the machine difference is adjusted by the machine difference adjusting unit, the first reference position and the second reference position are determined based on the printing position of the mark formed on the document.
The image reading device according to claim 7. An image forming part that forms an image on the front and back of the paper,
The first scanner that reads the image formed on the paper,
A second scanner provided on the downstream side of the first scanner and on the side opposite to the first scanner with a transport path for passing the paper, and reading an image formed on the paper.
It is an image formation system equipped with
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or , The printing position of the mark formed on the first surface of the document that can read the positional relationship from the front and back with the same reference as read by the first scanner, and the second surface of the document read by the second scanner. A machine difference adjusting unit that adjusts the machine difference between the first scanner and the second scanner based on the printed position of the formed mark, and
When the machine difference is adjusted by the machine difference adjusting unit, the first reference position, which is the reference position of the mark formed on the first surface of the paper, and the reference of the mark formed on the second surface of the paper. A position adjustment unit that determines the second reference position, which is the position, and
The first reference deviation amount, which is the deviation amount between the first reference position determined by the position adjusting unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. The second reference deviation amount, which is the deviation amount between the second reference position determined by the position adjusting unit and the printing position of the mark formed on the second surface of the paper read by the second scanner. With a monitoring unit that monitors
To prepare
Image formation system. The position adjusting unit
Feedback for adjusting the printing position when a mark is formed on the paper based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. Performed on the image forming unit
The image forming system according to claim 9. The machine difference adjustment unit
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner. Adjusting the difference between the first scanner and the second scanner,
The image forming system according to claim 9 or 10. A reversing path for reversing the paper is provided between the first scanner and the second scanner, or on the upstream side of the first scanner.
When the machine difference is adjusted by the machine difference adjusting unit, the first scanner reads an image formed on paper that has not been reversed by the inversion path, and the second scanner is inverted by the inversion path. Read the image formed on the paper
The image forming system according to claim 11. The machine difference adjustment unit
The machine difference is adjusted based on the marks formed on the first surface of the same paper read by the first scanner and the second scanner.
The image forming system according to claim 11 or 12. The machine difference adjustment unit
The machine difference is adjusted based on the marks formed on the first surface of the different sheets read by the first scanner and the second scanner.
The image forming system according to claim 11 or 12. The machine difference adjustment unit
At the printing position of the mark formed on the first surface of the original document read by the first scanner and the printing position of the mark formed on the second surface of the original document read by the second scanner. Based on this, the difference between the first scanner and the second scanner is adjusted.
The image forming system according to claim 9 or 10. The position adjusting unit
When the machine difference is adjusted by the machine difference adjusting unit, the first reference position and the second reference position are determined based on the printing position of the mark formed on the document.
The image forming system according to claim 15. The first scanner that reads the image formed on the paper,
A second scanner provided on the downstream side of the first scanner and on the side opposite to the first scanner with a transport path for passing the paper, and reading an image formed on the paper.
A computer that controls an image reader equipped with
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or , The printing position of the mark formed on the first surface of the document that can read the positional relationship from the front and back with the same reference as read by the first scanner, and the second surface of the document read by the second scanner. A machine difference adjusting unit that adjusts the machine difference between the first scanner and the second scanner based on the printed position of the formed mark, and
When the machine difference is adjusted by the machine difference adjusting unit, the first reference position, which is the reference position of the mark formed on the first surface of the paper, and the reference of the mark formed on the second surface of the paper. A position adjustment unit that determines the second reference position, which is the position, and
The first reference deviation amount, which is the deviation amount between the first reference position determined by the position adjusting unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. The second reference deviation amount, which is the deviation amount between the second reference position determined by the position adjusting unit and the printing position of the mark formed on the second surface of the paper read by the second scanner. With a monitoring unit that monitors
A program to function as.

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