JP6561787B2 - Image reading apparatus and image forming system - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming system.

  2. Description of the Related Art Conventionally, when a sheet is conveyed by a conveyance roller, there is one that changes the print setting of the sheet by specifying the type of the sheet according to the repulsive force when the sheet is pushed up (see, for example, Patent Document 1). .

  When the paper is transported to the print head by the transport roller, the height of the platen is adjusted according to the thickness of the paper so that the distance between the print head and the paper surface is always constant. Some perform a printing operation (see, for example, Patent Document 2).

JP 2003-292170 A JP 2001-277618 A

  The conventional technique as described in Patent Document 1 changes the print setting of a sheet depending on the type of the sheet. However, the prior art as described in Patent Document 1 specifies the type of paper before the paper reaches the downstream transport roller. Therefore, the conventional technology as described in Patent Document 1 does not specify the type of paper in a state where the paper is sandwiched between the upstream transport roller and the downstream transport roller.

  The conventional technology as described in Patent Document 2 is adjusted so that the distance between the print head and the surface of the paper is always constant even if the thickness of the paper is different. Therefore, the conventional technology as described in Patent Document 2 does not adjust the distance between the print head and the paper surface in a state where the paper is sandwiched between the upstream conveyance roller and the downstream conveyance roller. Absent.

  That is, in the conventional techniques as described in Patent Documents 1 and 2, an operation corresponding to the sheet sandwiched between the upstream-side transport roller and the downstream-side transport roller is not assumed.

  By the way, when the paper is transported in a state of being sandwiched between the upstream transport roller and the downstream transport roller, the color of the image formed on the paper is measured by the colorimeter. Is irradiated.

  Therefore, when the paper to be transported is thin paper, the colorimeter is affected by the diffusion of the illumination light transmitted through the paper. The influence of the diffusion of the illumination light varies depending on the distance between the background member and the colorimeter. In this case, the allowable range of the distance between the background member and the colorimeter is narrow. On the other hand, when the paper to be transported is a thick paper, the colorimeter is not easily affected by the diffusion of the illumination light transmitted through the paper. Therefore, if the transported paper is thick paper, the allowable range of the distance between the background member and the colorimeter is wider than when the transported paper is thin paper, but other influences need to be taken into account. There is.

  Specifically, in the state where the thick paper is sandwiched between the upstream transport roller and the downstream transport roller, if the thick paper passes through one of the transport rollers, the thick paper is distorted by bending, so the transport force is increased. Need to increase. However, if the conveyance force of the thick paper is increased by increasing the pressing force of the conveyance roller, instantaneous conveyance speed fluctuation occurs when the thick paper passes through any one of the conveyance rollers. Therefore, it is impossible to measure the color of the image formed on the cardboard at the presumed reading timing.

  Further, the force by which the background member pushes up the paper is set to a low load so that paper jam does not occur even if the paper is thin. Further, when the thick paper passes through one of the transport rollers in a state where the thick paper is sandwiched between the upstream transport roller and the downstream transport roller, the thick paper is distorted by bending. Therefore, if the cardboard is conveyed with the background member set to a low load, the distance between the colorimeter and the background member varies. As a result, if the distance between the colorimeter and the background member exceeds the allowable range, the colorimeter cannot accurately measure the color.

  Therefore, in the prior arts described in Patent Documents 1 and 2, there is a possibility that the color formed on the patch formed on the paper at the read timing assumed in advance cannot be accurately measured.

  The present invention has been made in order to solve the conventional problems, and an object of the present invention is to perform image reading capable of accurately measuring a patch formed on a sheet at a reading timing assumed in advance. An apparatus and an image forming system are provided.

In order to achieve the above object, an image reading apparatus according to the present invention is disposed opposite to a conveyance roller for conveying a sheet, a colorimeter for colorimetrically measuring an image formed on the sheet, and the colorimeter. A background member, and a position control unit that controls the position of at least one of the colorimeter and the background member within a range of a limit distance based on physical properties of the paper, and the transport roller includes a first roller and roller, and a second roller disposed opposite to the first roller, when the pre-Symbol sheet is conveyed, it is freely adjust the distance between the background member and the colorimeter The position control unit is arranged on the same side surface of the second roller and the paper among the colorimeter and the background member when the paper passes between the colorimeter and the background member. provided, the second roller contact with the sheet Moving ones either one to match the first direction away from said first roller in response to the thickness of the sheet lifting and while, in the same direction as the first direction according to the thickness of the sheet Let

  According to this image reading apparatus, it is possible to accurately measure the color of a patch formed on a sheet at a predetermined reading timing.

  In the image reading apparatus according to the present invention, it is preferable that the physical properties of the paper are determined based on a paper type of the paper.

  According to this image reading apparatus, it is possible to maintain the accuracy of reading patches.

  In the image reading apparatus according to the present invention, it is preferable that the position control unit moves the colorimeter and the background member that are close to the second roller to a position away from the sheet.

  According to this image reading apparatus, the conveyance force of the conveyance roller can be reduced.

  In the image reading apparatus according to the present invention, the second roller on the upstream side and the second roller on the downstream side are provided along the same side surface of the paper, and the position Preferably, the control unit moves the colorimeter and the background member on the same side to a position away from the paper.

  According to this image reading apparatus, the sheet conveyance resistance is reduced, and the pressing force of the conveyance roller can be set low.

  Further, in the image reading apparatus according to the present invention, the position of the gap between the colorimeter and the background member is defined by a first nip formed on the upstream conveying roller and the downstream side. It is preferable that the second nip formed on the conveying roller is adjusted on a nip line.

  According to this image reading apparatus, the bent state of the paper P within the colorimetric range of the colorimeter can be eliminated.

  In the image reading apparatus according to the present invention, the colorimeter includes a light source unit, a light receiving optical system that receives light including light reflected by light emitted from the light source unit, and light received by the light receiving optical system. A spectroscopic optical system that outputs a spectroscopic spectrum; and a calculation unit that calculates a colorimetric value based on the spectroscopic spectrum output by the spectroscopic optical system, wherein the transport roller includes a plurality of transport rollers along the transport direction of the paper. It is preferable that some of the plurality of transport rollers are arranged at positions along the reading center line of the light receiving optical system.

  According to this image reading apparatus, colorimetry can be performed with a colorimeter particularly remarkably accurately.

  In the image reading apparatus according to the present invention, it is preferable that the paper type of the paper includes at least one of the thickness, basis weight, and material of the paper.

  According to this image reading apparatus, the limit distance between the colorimeter and the background member can be determined particularly remarkably accurately.

  In the image reading apparatus according to the present invention, it is preferable that the limit distance is set in a range in which the colorimetric accuracy of the colorimeter can be maintained.

  According to this image reading apparatus, it is possible to eliminate the bent state of the paper without reducing the accuracy of reading the patch.

  Further, in the image reading apparatus according to the present invention, the first roller conveys the paper by a driving force, the second roller forms a nip with the first roller, and the first roller It is preferable that the paper is conveyed by following the driving of one roller.

  According to this image reading apparatus, it is possible to effectively utilize the sheet passing area where the sheet is conveyed.

  In the image reading apparatus according to the present invention, the scanner reads an image formed on the sheet along the width direction of the sheet, and corrects the reading result of the scanner based on the color measurement result of the colorimeter. It is preferable to further include a correction processing unit.

  According to this image reading apparatus, the color information read by the scanner can be fed back to the image forming apparatus as an accurate value.

  In order to achieve the above object, an image forming system according to the present invention includes the above-described image reading apparatus and an image forming apparatus that forms an image on the sheet.

  According to this image forming system, when the user wants to output an image to be printed, the image can be automatically corrected with high productivity by reading it with a scanner.

  According to the present invention, it is possible to accurately measure a patch formed on a sheet at a reading timing assumed in advance.

1 is a diagram illustrating an example of an overall configuration of an image forming system 1 according to Embodiment 1. FIG. 2 is a diagram illustrating an example of an internal configuration of an image forming apparatus 5 according to Embodiment 1. FIG. 2 is a diagram illustrating an example of an internal configuration of an image reading apparatus 7 according to Embodiment 1. FIG. 3 is a diagram illustrating an example of a functional configuration of a scanner 701 according to Embodiment 1. FIG. 4 is a block diagram illustrating an example of a functional configuration of a colorimeter 703 according to Embodiment 1. FIG. 2 is a block diagram illustrating an example of a functional configuration of an image reading apparatus according to Embodiment 1. FIG. It is a figure which illustrates roughly about the light quantity which concerns on Embodiment 1. FIG. 6 is a diagram illustrating an example in which the direction in which the colorimeter 703 according to Embodiment 1 is separated from the paper P is matched with the direction in which the second roller 731b is separated from the paper P. FIG. 6 is a diagram illustrating an example in which a direction in which a background member 705 according to Embodiment 1 is separated from a paper P is matched with a direction in which a second roller 731b is separated from the paper P. FIG. FIG. 10 is a diagram illustrating an example in which a direction in which a colorimeter 703 according to Embodiment 2 is separated is matched with a direction in which a second roller 731b is separated from a sheet P. FIG. 10 is a diagram illustrating an example in which a direction in which a colorimeter 703 according to Embodiment 3 is separated from a direction in which a second roller 731b is separated from a sheet P It is a front view of the colorimeter 703, the background member 705, and the 2nd roller 731b which concern on Embodiment 4. FIG. 10 is a diagram illustrating a relationship between a distance between a colorimeter 703 and a background member 705 according to Embodiment 4 and a paper thickness. FIG. 10 is a top view of a colorimeter 703, a background member 705, and a second roller 731b according to Embodiment 4. It is a top view of the colorimeter 703 and the 2nd roller 731b which concern on Embodiment 5. It is a front view of the conventional colorimeter 703 and the background member 705. It is a left side view of a conventional colorimeter 703 and a background member 705. It is a figure which shows the direction which the conventional background member 705 leaves, and the direction from which the 2nd roller 731b leaves.

  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.
FIG. 1 is a diagram illustrating an example of the overall configuration of an image forming system 1 according to the first embodiment. 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 discharging 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 an image is formed by the image forming device 5 and executes various processes. The paper discharge device 8 includes a paper discharge tray 9 and discharges the paper P conveyed from the image reading device 7 to the paper discharge tray 9.

  Next, the image forming apparatus 5 will be specifically described. FIG. 2 is a diagram illustrating an example of an 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 copying machine, acquires image information by reading a color image formed on a document T, and superimposes colors based on the acquired image information. A device for forming a color image. The image forming apparatus 5 is suitable for being applied to a color printer or facsimile apparatus, a multifunction machine of these, etc. in addition to a color copying machine.

  The image forming apparatus 5 includes an image forming apparatus main body 11. A color image reading unit 12 and an automatic document feeder 14 are disposed 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 conveyance unit 30, which will be described in detail 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 feeding mode. Here, the automatic paper feed mode is an operation of feeding a document T placed on the automatic document feeder 14 and reading an image printed on the document T.

  Specifically, the automatic document feeder 14 includes a document placement unit 141, a roller 142 a, a roller 142 b, a roller 143, a roller 144, a reversing unit 145, and a paper discharge tray 146. On the document placing portion 141, one or a plurality of documents T are placed. A roller 142 a and a roller 142 b are provided on the downstream side of the document placing portion 141. A roller 143 is provided on the downstream side of the rollers 142a and 142b. Further, the automatic document feeder 14 includes a positioning detector 81 on the outer peripheral side of the roller 143.

  When the automatic paper feeding mode is selected, the document T fed out from the document placement unit 141 is rotated by a roller 143 and conveyed. Note that when the document T is placed on the document placement unit 141 and the automatic paper feeding mode is selected, the recording surface of the document T may be in an upward state.

  In addition, the original T is read by the image reading unit 12, then conveyed by the roller 144, and discharged to the discharge tray 146. The automatic document feeder 14 can cause the image reading unit 12 to read not only the recording surface of the document T but also the back side of the recording surface of the document T by conveying the document T to the reversing unit 145.

  Next, the positioning detection unit 81 will be described. The positioning detection unit 81 detects the document T on which an image is printed. The positioning detection unit 81 is configured by, for example, a reflective photosensor. When the document T is detected, the positioning detection unit 81 rises an output signal. 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 in which the document T passes the positioning detection unit 81.

  Next, the image reading unit 12 will be described. The image reading unit 12 performs an operation of reading a color image formed on the document T, that is, a color image printed on the document T. The image reading unit 12 includes 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, and 126, an imaging optical unit 127, and an optical (not shown). A drive unit is provided.

  The light source 123 irradiates the document T with light. An optical drive unit (not shown) relatively moves the document T or the image sensor 128 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.

  Accordingly, the document T is conveyed by the automatic document feeder 14, and the image on the one side or both sides of the document T is scanned and exposed by the optical system of the image reading unit 12. Next, incident light reflecting the image reading operation is read by the image sensor 128. In the Plato mode, the image sensor 128 outputs an RGB color system image reading signal Sout obtained by reading the document T. Here, the platen 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 three-line color CCD imaging device is used. The image sensor 128 is configured by arranging a plurality of light receiving element arrays in the main scanning direction. Specifically, each of the red (R), green (G), and blue (B) light detection reading sensors divides pixels at different positions in the sub-scanning direction orthogonal to the main scanning direction. Then, the optical information of each of the R color, G color, and B color is read simultaneously. For example, in the automatic paper feed mode, when the document T is reversed U-shaped 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 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 an R color component, a G color component, and a B color component. Based on the three-dimensional color information conversion table, the image processing unit 43 converts the image data, that is, 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, details of the image forming unit 60 will be described. The image forming unit 60 uses electrophotographic process technology and forms an intermediate transfer type color image. The image forming unit 60 employs 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, Dk. The image forming unit 60 includes image forming units 601Y, 601M, 601C, and 601K for each color, an intermediate transfer unit 620, and a fixing unit 630 that fixes 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 unit 614Y is disposed around the photosensitive drum 613Y and uniformly charges the surface of the photosensitive drum 613Y to a negative polarity 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 a toner image by attaching Y color component toner to the surface of the photosensitive drum 613Y. The cleaning unit 616Y removes 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 color of the image to be formed is different, the description thereof is omitted.

  Note that the image forming units 601Y, 601M, 601C, and 601K are collectively referred to as an image forming unit 601. The LED writing units 611Y, 611M, 611C, and 611K are collectively referred to as the LED writing unit 611. The developing units 612Y, 612M, 612C, and 612K are collectively referred to as the developing unit 612. The photosensitive drums 613Y, 613M, 613C, and 613K are collectively referred to as the photosensitive drum 613. The charging units 614Y, 614M, 614C, and 614K are collectively referred to as a charging unit 614. The cleaning units 616Y, 616M, 616C, and 616K are collectively referred to as a cleaning unit 616.

  Next, the intermediate transfer unit 620 will be described. The intermediate transfer unit 620 includes an intermediate transfer belt 621, primary transfer rollers 622Y, 622M, 622C, and 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 disposed downstream of the K component primary transfer roller 622K in the belt traveling direction is a drive roller. As the drive roller rotates, the intermediate transfer belt 621 travels at a constant speed in the arrow Z direction.

  The primary transfer rollers 622Y, 622M, 622C, and 622K are disposed on the inner peripheral surface side of the intermediate transfer belt 621 so as to face the photosensitive drums 613 of the respective color components. 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 interposed therebetween. As a result, a primary transfer nip for transferring a toner image from the photosensitive drums 613Y, 613M, 613C, and 613K to the intermediate transfer belt 621 is formed.

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

  The secondary transfer roller 623 is disposed 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 disposed to face the intermediate transfer belt 621 is called a backup roller. The secondary transfer roller 623 is pressed against the backup roller with the intermediate transfer belt 621 interposed therebetween, so that 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 primarily transferred to the intermediate transfer belt 621 in order. Specifically, a primary transfer bias is applied to the primary transfer roller 622, and an electric charge having a polarity opposite to that of the toner is applied to the back 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.

  Thereafter, 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, and a charge having a polarity opposite to that of the toner is applied to the back 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 sheet P to which the toner image is transferred is conveyed toward the fixing unit 630.

  The belt cleaning device 624 includes a belt cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 621. The belt cleaning device 624 removes 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 looped around a plurality of support rollers including the secondary transfer roller 623, a so-called belt. A secondary transfer unit of the formula may be employed.

  Next, the fixing unit 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 73, and fixes the toner image transferred by the image forming unit 60 onto the paper P.

  Specifically, the heating unit 633 is provided inside the heating roller 631 and intermittently heats the heating roller 631. The pressure roller 632 is disposed 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 detector 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 detection unit 83 that detects the temperature of the heating roller 631. The fixing unit 630 forms a fixing nip between the heating roller 631 and the pressure roller 632 by bringing the heating roller 631 and the pressure roller 632 into pressure contact with each other.

  The fixing unit 630 fixes the transferred toner image on the paper P through the action of pressure by the pressure roller 632 and 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 by the paper discharge roller 304 and is conveyed to the image reading device 7, for example. The paper P on which the image is printed may be stacked on the paper discharge tray 305 without being conveyed to the image reading device 7.

  Next, the paper feeding 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 feed cassette 200 stores 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 conveyance unit 30 will be described. The transport unit 30 includes a transport path 300 and transports the paper P along the transport path 300. The conveyance path 300 includes a paper feed roller 302A, conveyance rollers 302B, 302C, and 302D, a registration roller 303, and the like.

  The conveyance path 300 conveys the paper P fed from the paper feeding unit 20 to the image forming unit 60. When image formation is also performed on the back surface of the paper P, after the image formation is performed on the front surface of the paper P, the paper P is separated by the branching unit 306 by the circulation paper path 307A, the reverse conveyance path 307B, The paper is conveyed in the order of the paper feed conveyance 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 (not shown) or the image processing unit 43 via the control unit 41. The image memory is composed of, for example, a hard disk.

  Specifically, the control unit 41 is configured mainly with a CPU, a ROM, a RAM, and an I / O interface (not shown). In the control unit 41, the CPU reads out various programs corresponding to the processing contents from the ROM or a storage unit (not shown), expands the program in the RAM, and cooperates with the expanded various programs, thereby controlling the operation of 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 implement | achieved when the control part 41 runs a predetermined | prescribed control program.

  Next, the image reading device 7 will be specifically described. FIG. 3 is a diagram illustrating an example of an internal configuration of the image reading apparatus 7 according to the first embodiment. 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 apparatus 7 includes a control unit 51, a scanner 701 a, a scanner 701 b, a colorimeter 703, background members 705 a to 705 c, a conveyance roller 731, and a sheet passing path 700. The paper passing 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.

  For example, when the image reading device 7 receives the paper P supplied from the image forming device 5, the image reading device 7 causes the scanner 701 a, the scanner 701 b, or the colorimeter 703 to detect an 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, various functions including a position control unit 511, a conveyance control unit 512, and a correction processing unit 515 described later 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 scanner 701a and the scanner 701b are respectively arranged to face the paper P that passes through the paper passing path 700, and read an image printed on the paper P. The scanner 701a scans the back side of the paper P, and the read result is used for checking, for example, whether the image printed on the paper P is misaligned or whether there is an unexpected image. On the other hand, the scanner 701b reads the surface of the paper P, and performs an operation of reading an image printed on the paper P, for example, a patch (not shown). Note that the scanner 701a and the scanner 701b are collectively referred to as a scanner 701.

  Note that the image reading apparatus 7 is operated by either an inline method or an offline method.

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

  The scanner 701 will be specifically described. FIG. 4 is a diagram illustrating an example of a functional configuration of the scanner 701 according to the first embodiment. The scanner 701 is provided on the upstream side of the colorimeter 703, and includes an illuminating device 713 that irradiates light to the paper P that passes through the reading position and a plurality of image sensors 712 that perform photoelectric conversion for each pixel in the paper width direction. It is composed mainly of line image sensors arranged side by side. The reading range of the scanner 701 is set so that the maximum width of the paper P supplied from the image forming apparatus 5 can be read. The scanner 701 repeats the image reading operation for one line extending in the paper width direction in accordance with the paper passing operation of the paper P passing the reading position, thereby two-dimensionally printing the image printed on the paper P. Read as an image. The read image is used as a read value of the image.

  The image sensor 712 can be realized by a CCD (Charge Coupled Device). The CCD is an optical sensor that performs an image reading operation on the paper P at a reading position, and functions as a color line sensor that can read the entire width range in the width direction of the paper P by being arranged in a line. It is.

  The scanner 701 operates in cooperation with an optical system 710 and an illumination device 713 that illuminates a reading position, in addition to the image sensor 712, when actually performing a reading operation. The optical system 710 is for guiding the image at the reading position to the CCD, and includes a plurality of mirrors and a plurality of lenses.

  In other words, the scanner 701 has a line image sensor that reads the paper P along the width direction of the paper P, and reads the paper P in the paper passing direction with the horizontal width of the paper P as one line. The read value of the image can be acquired.

  The background member 705 is disposed at a position facing the scanner 701, and is used when the light irradiated on the paper P is reflected.

  The colorimeter 703 is on the downstream side of the scanner 701 and is disposed at a position facing the paper P to be passed through the paper passing path 700. The colorimeter 703 guarantees the absolute value of the color of the image formed on the paper P by, for example, measuring the color of a patch printed on the paper P.

  Next, the colorimeter 703 will be specifically described. FIG. 5 is a block diagram illustrating an example of a functional configuration of the colorimeter 703 according to the first embodiment. As shown in FIG. 5, the colorimeter 703 includes a light source unit 721, an illumination optical system 722, a light receiving optical system 723, a light guide unit 724, a spectral optical system 725, and a calculation unit 726. The light receiving optical system 723 and the light guide unit 724 function as the reading unit 707 of the colorimeter 703.

  The light source unit 721 irradiates the paper P with illumination light. The light source unit 721 is composed of a light emitting diode. Note that the light source unit 721 may be composed of other than a light emitting diode. For example, the light source unit 721 may be composed of a halogen lamp or a xenon lamp. Further, the light source unit 721 may be replaced with another type of illumination mechanism. For example, instead of the light source unit 721, an illumination opening may be disposed at a radiation position where the illumination light is emitted, and the illumination light may be guided from the light source unit 721 to the illumination opening by a light guide mechanism such as an optical fiber.

  The illumination optical system 722 guides illumination light from the light source unit 721 to the paper P. Note that the illumination optical system 722 may be omitted.

  The light receiving optical system 723 is a collimator, and converts the parallel light flux into a convergent light flux. The light guide unit 724 guides the light beam from the light receiving optical system 723 to the spectroscopic optical system 725. The spectroscopic optical system 725 performs spectroscopic measurement of the guided light beam. The spectroscopic optical system 725 divides the light beam by a wavelength dispersion element such as a diffraction grating or a prism, detects a change in intensity due to the wavelength by a sensor array or the like, and outputs a spectral spectrum. Note that the spectroscopic optical system 725 may be replaced with a mechanism that performs measurement for colorimetry other than spectroscopic measurement. For example, the spectroscopic optical system 725 may be replaced with a mechanism that directly detects a stimulus value using an RGB sensor or the like.

  The calculation unit 726 calculates a colorimetric value based on the spectral spectrum output from the spectroscopic optical system 725. The calculation unit 726 is realized by causing an embedded computer to execute a program such as firmware. Note that all or part of the functions of the arithmetic unit 726 may be realized by hardware that does not execute a program. The hardware is, for example, an electronic circuit including an operational amplifier, a comparator, and a logic circuit.

  That is, the colorimeter 703 emits visible light from a visible light source (not shown) toward the patch, acquires a spectral spectrum of reflected light of visible light, and moves to a predetermined color system based on the acquired spectral spectrum. Is performed, and the color of the patch is derived.

  The color measurement result of the patch is generated as numerical data expressed 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. The

  The colorimetric 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 width of the patch along the paper width direction. Specifically, the lens unit that acquires the reflected light of the patch is, for example, about 4 mm.

  As described above, the colorimeter 703 performs colorimetry only in a certain viewing angle range, and therefore can reproduce color information with higher accuracy than the scanner 701. For this reason, if the sheet P passes through the sheet passing path 700 only once, the color measurement is performed only for one row of patches.

  Next, the functional configuration of the image reading device 7 will be described. FIG. 6 is a block diagram illustrating an example of a functional configuration of the image reading apparatus 7 according to the first embodiment. The conveyance control unit 512 controls driving of the conveyance roller 731.

  The transport roller 731 includes a first roller 731a and a second roller 731b. The first roller 731a conveys the paper P by a driving force. The second roller 731b is disposed to face the first roller 731a. Specifically, the second roller 731b is normally urged toward the first roller 731a by an urging member made of an elastic body such as a spring so as to maintain contact with the paper P. Is moved away from the first roller 731a by the thickness of the paper P. In this way, the first roller 731a and the paper P, and the paper P and the second roller 731b are configured to always maintain contact.

  That is, the second roller 731b forms a nip with the first roller 731a, and conveys the paper P by following the driving of the first roller 731a.

  The position control unit 511 controls the position of at least one of the colorimeter 703 and the background member 705 within the range of the limit distance based on the physical properties of the paper P. The physical properties of the paper P are determined based on the paper type of the paper P. The paper type of the paper P includes at least one of the thickness, basis weight, and material of the paper P. The limit distance is set in a range where the colorimetric accuracy of the colorimeter 703 can be maintained.

  The correction processing unit 515 obtains the correction amount of the image printed on the paper P. Specifically, the correction processing unit 515 corrects the color information of the patch read by the scanner 701 based on the colorimetric value of the patch measured by the colorimeter 703. More specifically, the correction processing unit 515 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, and accurate A correction amount is obtained.

  The image processing unit 43 optimizes an image to be formed by the image forming unit 60 based on the correction amount calculated by the correction processing unit 515. The image optimization processing executed by the image processing unit 43 includes front / back position adjustment, density adjustment, color adjustment, and the like of the image 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 an image formed on the paper P based on the color information corrected by the correction processing unit 515. The image processing unit 43 issues a command to form an image on the paper P to the image forming unit 60 based on the correction result.

  Next, the amount of light received by the colorimeter 703 will be specifically described. FIG. 7 is a diagram schematically illustrating the amount of light according to the first embodiment. As shown in FIG. 7, the amount of light used for colorimetry is not only the light reflected by the background member 705 that has passed through the paper P and again transmitted through the paper P, but also the light that has reflected the paper P from the illumination light, that is, Light that has not passed through the paper P is also added.

  The colorimeter 703 performs color measurement based on the amount of light, but the amount of light varies depending on the color, material, and area of the background member 705, the distance between the background member 705 and the paper P, and the like. Is.

  Specifically, the illumination light diffuses when passing through the paper P. The transmitted light diffused by the illumination light varies depending on the distance between the background member 705 and the back side of the paper P. As a result, since the reflected light also fluctuates, the amount of light transmitted through the paper P fluctuates. As the amount of light varies, the colorimetric value of the colorimeter 703 also varies, so the colorimetric value does not become an accurate value.

  More specifically, when any of the above distances varies by 0.5 mm, the color difference ΔE00 calculated from the colorimetric values varies by about 1.0. Note that a gap between paper conveyance guides 741 to be described later is configured to be about 2 to 3 mm. However, the colorimetric value changes greatly due to flapping of the paper P within the gaps between the paper conveyance guides 741. In the scanner 701, the gap through which the paper P is conveyed is suppressed to about 1 mm. However, the colorimeter 703 cannot accept a height fluctuation of about 1 mm.

  Further, when the paper P is a thin paper, in order to accurately measure the color of the paper P with the colorimeter 703, the distance between the colorimeter 703 and the paper P is kept constant while the paper P and the background member 705 are measured. It is necessary to make the distance between them constant. That is, if the paper P is easy to transmit light, the colorimetric value of the colorimeter 703 is stabilized by bringing the back side of the paper P and the background member 705 into close contact.

  However, when the paper P is a thick paper, the transmitted light passing through the paper P is reduced, so that the influence of the distance is reduced. Therefore, the allowable range of height fluctuation of the paper P differs depending on the paper type.

  Therefore, conventionally, in order to make the distance between the colorimeter 703 and the paper P constant and to keep the distance between the paper P and the background member 705 constant, the reading unit 707 of the colorimeter 703 is used. The paper P is actively held in the vicinity. Thereby, regardless of the thickness of the paper P, the distance between the front surface of the paper P and the colorimeter 703, the back surface of the paper P, and the background member 705 can be stabilized.

  A conventional example will be specifically described. FIG. 16 is a front view of a conventional colorimeter 703 and background member 705. FIG. 17 is a left side view of a conventional colorimeter 703 and background member 705. As shown in FIGS. 16 and 17, ribs 751 and rollers 752 are provided on both sides of the reading unit 707 of the colorimeter 703, and an elastic member 753 is provided on the back side of the background member 705. The elastic member 753 is a member having elasticity, for example, a spring shape. Therefore, the background member 705 is spring-biased by the elastic member 753.

  Furthermore, the background member 705 is a position facing the rib 751 and the roller 752 with respect to the sheet passing position, and a backing roller 755 is provided on both sides. The backing roller 755 is supported by a support member 754. The support member 754 is provided with an elastic member 753.

  Therefore, the backing roller 755 is spring-biased by the elastic member 753 via the support member 754. Note that the background member 705 is independently movable in the vertical direction with respect to the conveyed paper P. That is, when the colorimeter 703 measures the sheet P, the rib 751 and the roller 752 and the backing roller 755 remain in contact with each other by the spring bias of the elastic member 753, but the background member 705 Along the back direction of P, it can move in a direction away from the back side of the paper P and a direction approaching the back side of the paper P.

  The paper P is transported between the paper transport guide 741a and the paper transport guide 741b along the transport direction of the paper P. The leading edge of the paper P pushes down the background member 705 by the force by which the paper P is conveyed, and the paper P is conveyed between the ribs 751 and the rollers 752 and the background member 705. Thus, the distance between the colorimeter 703 and the surface of the paper P is stable, and the back side of the paper P and the front side of the background member 705 are in contact with each other. As a result, the distance between the paper P and the colorimeter 703 and the distance between the paper P and the background member 705 are stable even while the paper P is being conveyed. Therefore, color measurement by the colorimeter 703 can be performed with high accuracy.

  However, the conveyance roller 731 is provided on each of the upstream side and the downstream side of the colorimeter 703 along the conveyance direction of the paper P, and the second roller 831b is provided on the same surface side of the paper P as the colorimeter 703. When the paper P is provided and is thick, the posture of the paper P is a downward convex shape during conveyance.

  Thereby, since the conveyance load of the paper P becomes high, it is necessary to increase the conveyance force of the conveyance roller 731. In order to increase the conveyance force of the conveyance roller 731, it is necessary to increase the load with which the second roller 731 b on the driven side presses the paper P. That is, since the conveyance resistance increases due to the bending of the sheet P, it is necessary to increase the pressing force of the second roller 731b on the driven side.

  In this case, when the paper P enters the transport roller 731 or when the paper P leaves the transport roller 731, that is, when the paper P passes through the transport roller 731, the transport speed of the paper P instantaneously varies. To do. As a result, it is not possible to measure the color of the image formed on the paper P at the presumed reading timing.

  That is, since an image at the reading timing, specifically, the position of the patch is shifted, it is necessary to increase the size of the patch by an amount corresponding to the shift. As described above, if the size of the patch is increased, the number of patches that can be put on one sheet of paper P is reduced, and wasteful paper is increased. Therefore, in order to reduce wasted paper, the smaller the patch size, the better.

  Further, the unit such as the background member 705 is pushed toward the colorimeter 703 by the elastic member 753, but when the paper P enters between the background member 705 and the colorimeter 703, the measurement is performed. It is pushed down in the direction away from the color meter 703. The load of the elastic member 753 is set to a low load, for example, 80 gf or less in order to prevent a paper jam from occurring when the thin paper P having a weak stiffness enters. Therefore, if the paper P is thin, the distance between the colorimeter 703 and the background member 705 can be kept within an allowable range by the pressing force of the elastic member 753, but the paper P is thick and strong. In the case of paper, it cannot be pushed toward the colorimeter 703 by the elastic member 753 due to gravity and curling of the paper P. As a result, the distance between the colorimeter 703 and the background member 705 cannot be suppressed within an allowable range.

  FIG. 18 is a diagram illustrating a direction in which the conventional background member 705 is separated and a direction in which the second roller 731 b is separated. As shown in FIG. 18, if the paper P is a thick paper, the second roller 731 b escapes in a direction away from the front side of the paper P, and the background member 705 escapes in a direction away from the back side of the paper P. As a result, the point where the roller 752 contacts the paper P and the point where the second roller 731b contacts the paper P are not on the same straight line. Thereby, since the paper P is distorted by bending, the conveyance force of the conveyance roller 731 must be increased. As a result, since the instantaneous conveyance speed fluctuates, the patch cannot be read at a reading timing assumed in advance, and the distance between the colorimeter 703 and the background member 705 also fluctuates. The reading accuracy also decreases.

  Therefore, not only the background member 705 but also the colorimeter 703 makes it possible to adjust the distance from the paper P when the paper P is conveyed. Further, when the paper P passes between the colorimeter 703 and the background member 705, the position control unit 511 detects that the second roller 731 b of the colorimeter 703 and the background member 705 is separated from the paper P. What is matched to one direction is moved in the same direction as the first direction.

  FIG. 8 is a diagram illustrating an example in which the direction in which the colorimeter 703 according to the first embodiment is separated from the paper P is matched with the direction in which the second roller 731 b is separated from the paper P. FIG. 9 is a diagram illustrating an example in which the direction in which the background member 705 according to the first embodiment is separated from the paper P is matched with the direction in which the second roller 731b is separated from the paper P.

  Ribs 751 and rollers 752 are provided on both sides of the reading unit 707 of the colorimeter 703, as in FIGS. FIG. 8 shows an example in which the second roller 731b is provided on the front side of the paper P, and the colorimeter 703 is provided on the front side of the paper P. In this case, the direction in which the second roller 731b is separated from the sheet P is the direction away from the surface of the sheet P, that is, the upward direction. Therefore, by moving the colorimeter 703 in the upward direction, the direction in which the colorimeter 703 is separated from the paper P is adjusted to the direction in which the second roller 731b is separated from the paper P.

  FIG. 9 shows an example in which the second roller 731b is provided on the back side of the paper P, and the background member 705 is provided on the back side of the paper P. In this case, the direction in which the second roller 731b is separated from the paper P is the direction away from the back surface of the paper P, that is, the downward direction. Therefore, by moving the background member 705 in the downward direction, the direction in which the background member 705 is separated from the paper P is adjusted to the direction in which the second roller 731b is separated from the paper P.

  Note that the movement mechanism of the background member 705 and the colorimeter 703 can be easily understood by those skilled in the art, and a detailed description thereof will be omitted. For example, the detection result of a rotary encoder (not shown) Based on this, the AC servo motor is controlled, the background member 705 is moved along the direction away from the back surface of the paper P, and the colorimeter 703 is moved along the direction away from the front surface of the paper P.

  Further, the paper transport guides 741a and 741b are collectively referred to as a paper transport guide 741.

  As described above, the image reading device 7 is configured such that the roller 752 is in contact with the paper P by matching the direction in which the colorimeter 703 or the background member 705 is separated from the paper P and the direction in which the second roller 731b is separated from the paper P. And the nip formed on the transport roller 731 are positioned on the same straight line. Thereby, the distortion of the paper P on the nip line is eliminated, and the bent state of the paper P is eliminated. Therefore, since the conveyance load of the paper P is reduced, it is not necessary to increase the conveyance force of the conveyance roller 731. Thereby, since the conveyance speed of the paper P is stabilized, the patch formed on the paper P can be read at a read timing assumed in advance.

  Further, since the paper P is not bent, the background member 705 is not moved in the direction away from the colorimeter 703. Thereby, since the distance between the colorimeter 703 and the background member 705 is suppressed within an allowable range, the color can be accurately measured by the colorimeter 703.

  In other words, when the paper P passes between the colorimeter 703 and the background member 705, the image reading device 7 has the second roller 731 b out of the paper P among the colorimeter 703 and the background member 705. Even if the paper P is a thick paper, it is possible to eliminate the distortion of the paper P on the nip line by moving the object that is adjusted to the first direction away from the paper P in the same direction as the first direction. Since the conveying force can be reduced, it is possible to accurately measure the color of the patch formed on the paper P at the time of a presumed reading timing.

  Further, in the image reading apparatus 7, the physical properties of the paper P are determined based on the paper type of the paper P, so that the limit distance between the colorimeter 703 and the background member 705 can be accurately determined. Therefore, the accuracy of reading the patch can be maintained.

  In the image reading device 7, the paper type of the paper P can be accurately identified by including at least one of the thickness, basis weight, and material of the paper P. The limit distance between the colorimeter 703 and the background member 705 can be determined particularly remarkably accurately.

  In the image reading device 7, the limit distance is set in a range in which the colorimetric accuracy of the colorimeter 703 can be maintained, so that the second roller 731 b of the colorimeter 703 or the background member 705 can be used. Even if the object that is aligned with the first direction away from the paper P is moved in the same direction as the first direction, the bent state of the paper P can be eliminated without reducing the accuracy of reading the patch.

  In the image reading device 7, the second roller 731 b follows the first roller 731 a, and the distance between the second roller 731 b and the paper P can be adjusted. In addition, since it also functions as a conveyance force adjustment function for the paper P, it is possible to effectively utilize the paper passing area where the paper P is conveyed.

  Further, in the image reading device 7, the color information read by the scanner 701 is changed to color information read by the colorimeter 703 by correcting the read result of the scanner 701 based on the colorimetric result of the colorimeter 703. Since it can be corrected, the color information read by the scanner 701 can be fed back to the image forming apparatus 5 as an accurate value.

  Further, since the image forming system 1 includes the image reading device 7 and the image forming device 5, color information read by the scanner 701 can be fed back to the image forming device 5 as an accurate value. When outputting an image to be printed, the image can be automatically corrected with high productivity by being read by the scanner 701.

  As described above, according to the image reading apparatus 7 according to the present embodiment, the conveyance roller 731 that conveys the paper P, the colorimeter 703 that measures the color of the image formed on the paper P, and the colorimeter 703. A background member 705 arranged oppositely and a position control unit 511 that controls at least one of the position of the colorimeter 703 and the background member 705 within the range of the limit distance based on the physical properties of the paper P are provided. The roller 731 includes a first roller 731a and a second roller 731b arranged to face the first roller 731a, and at least one of the colorimeter 703 and the background member 705 is fed with paper P. When the paper P passes between the colorimeter 703 and the background member 705, the position control unit 511 can adjust the distance between the colorimeter 703 and the background member 705. Out of Those second roller 731b is aligned in a first direction away from the sheet P, it is moved in the same direction as the first direction.

  As a result, it is possible to accurately measure the color of the patch formed on the paper P at the presumed reading timing.

  Further, according to the image reading apparatus 7 according to the present embodiment, the physical properties of the paper P are determined based on the paper type of the paper P.

  Thereby, the image reading device 7 can maintain the accuracy of reading the patch.

  Further, according to the image reading apparatus 7 according to the present embodiment, the paper type of the paper P includes at least one of the thickness, basis weight, and material of the paper P.

  As a result, the image reading apparatus 7 can determine the limit distance between the colorimeter 703 and the background member 705 particularly remarkably and accurately.

  Further, according to the image reading apparatus 7 according to the present embodiment, the limit distance is set in a range where the colorimetric accuracy of the colorimeter 703 can be maintained.

  Thereby, the image reading apparatus 7 can eliminate the bent state of the paper P without reducing the accuracy of reading the patch.

  Further, according to the image reading apparatus 7 according to the present embodiment, the first roller 731a transports the paper P by driving force, and the second roller 731b forms a nip with the first roller 731a. Then, the paper P is conveyed by following the driving of the first roller 731a.

  As a result, the image reading apparatus 7 can effectively utilize the paper passing area where the paper P is conveyed.

  In addition, according to the image reading apparatus 7 according to the present embodiment, the scanner 701 reads an image formed on the paper P along the width direction of the paper P and the color measurement result of the colorimeter 703. And a correction processing unit 515 that corrects the read result.

  Accordingly, the image reading device 7 can feed back the color information read by the scanner 701 to the image forming device 5 as an accurate value.

  Further, the image forming system 1 according to the present embodiment includes the image reading device 7 described above and the image forming device 5 that forms an image on the paper P.

  Accordingly, the image forming system 1 can automatically correct an image with high productivity by reading the image with the scanner 701 when the user outputs an image to be printed.

Embodiment 2. FIG.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the second embodiment, the distance between the upstream conveying roller 731 and the colorimeter 703 is arranged in a separated state compared to the distance between the downstream conveying roller 731 and the colorimeter 703. Yes.

  FIG. 10 is a diagram illustrating an example in which the direction in which the colorimeter 703 according to the second embodiment is separated is matched with the direction in which the second roller 731 b is separated from the paper P. As illustrated in FIG. 10, the position control unit 511 moves the colorimeter 703 and the background member 705 that are close to the second roller 731 b to a position away from the paper P.

  Thereby, since the bending state of the paper P becomes gentle, the conveyance force of the conveyance roller 731 can be reduced.

Embodiment 3. FIG.
In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. In the third embodiment, a case where the upstream and downstream second rollers 731b and the colorimeter 703 are on the front side of the paper P will be described.

  FIG. 11 is a diagram illustrating an example in which the direction in which the colorimeter 703 according to the third embodiment is separated is matched with the direction in which the second roller 731 b is separated from the paper P. As shown in FIG. 11, a second roller 731b on the upstream side and a second roller 731b on the downstream side are provided along the same side surface of the paper P, and the position control unit 511 performs colorimetry. Of the total 703 and the background member 705, the one on the same side is moved to a position away from the paper P.

  Accordingly, since the posture of the paper P can be maintained flat while the paper P is being transported, the transport resistance of the paper P is reduced, and the pressing force of the transport roller 731 can be set low.

Embodiment 4 FIG.
In the fourth embodiment, the same components as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted. In the fourth embodiment, a gap between the colorimeter 703 and the background member 705 will be specifically described.

  FIG. 12 is a front view of the colorimeter 703, the background member 705, and the second roller 731b according to the fourth embodiment. FIG. 13 is a diagram illustrating the relationship between the distance between the colorimeter 703 and the background member 705 according to the fourth embodiment and the paper thickness. FIG. 14 is a top view of the colorimeter 703, the background member 705, and the second roller 731b according to the fourth embodiment.

  As shown in FIGS. 12 and 14, the position of the gap between the colorimeter 703 and the background member 705 has a first nip formed on the upstream conveying roller 731 and a downstream conveying roller 731. And a second nip formed on the nip line.

  As shown in FIG. 13, the distance between the colorimeter 703 and the background member 705 is adjusted to increase as the paper thickness increases.

  As a result, by adjusting the position of the second roller 731b and the colorimeter 703 or the background member 705, the bent state of the paper P within the colorimetric range of the colorimeter 703 can be eliminated. .

Embodiment 5. FIG.
In the fifth embodiment, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted. In the fifth embodiment, the position of the reading unit 707 of the colorimeter 703 will be specifically described.

  FIG. 15 is a top view of the colorimeter 703 and the second roller 731b according to the fifth embodiment. As described with reference to FIG. 5, the colorimeter 703 illustrated in FIG. 15 includes at least a light source unit 721, a light receiving optical system 723 that receives light including light reflected by light emitted from the light source unit 721, and a light receiving optical unit. A spectroscopic optical system 725 that outputs a spectroscopic spectrum from light received by the system 723 and an arithmetic unit 726 that calculates a colorimetric value based on the spectroscopic spectrum output from the spectroscopic optical system 725 are provided.

  As shown in FIG. 15, a plurality of conveyance rollers 731 are provided along the conveyance direction of the paper P, and are arranged at positions along the reading center line of the light receiving optical system 723 among the plurality of conveyance rollers 731. There is something.

  As a result, curling of the wave of the sheet P passing through the reading unit 707 of the colorimeter 703 can be pressed down, so that the colorimeter 703 can perform color measurement particularly remarkably accurately.

  As shown in FIG. 15, the transport roller 731 may be arranged other than on the reading center line.

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

  For example, in the present embodiment, an example of an arrangement configuration in which the color P 703 and the background member 705 are provided above and below the paper P in the direction in which the paper P is conveyed horizontally has been described. It is not limited. For example, it may be a configuration in which the paper P is conveyed in the vertical direction, and the colorimeter 703 and the background member 705 are provided on the left and right of the paper P.

  In addition, 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. However, the present invention is not limited to this, and L * a * It may be determined by a different color system such as b * color system.

DESCRIPTION OF SYMBOLS 1 Image forming system 3 Paper feeding apparatus 5 Image forming apparatus 7 Image reader 700 Paper feed path 701,701a, 701b Scanner 703 Colorimeter 705,705a-705c Background member 707 Reading part 710 Optical system 712 Image sensor 713 Illuminating device 721 Light source unit 722 Illumination optical system 723 Light receiving optical system 724 Light guide unit 725 Spectroscopic optical system 726 Calculation units 731, 731 a and 731 b Transport rollers 741, 741 a and 741 b Paper transport guide 751 Rib 752 Roll 753 Elastic member 754 Support member 755 Backing roller 8 Discharge device 9 Discharge tray 11 Image forming apparatus main body 12 Image reading unit 121 First platen glass 122 Second platen glass 123 Light source 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 Discharge tray 20 Paper feed unit 200 Paper feed cassette 201 Feed roller 30 Transport unit 300 Transport path 302A Paper feed roller 302B, 302C, 302D Transport Roller 303 Registration roller 304 Paper discharge roller 305 Paper discharge tray 306 Branch part 307A Circulating paper path 307B Reverse conveyance path 307C Refeed conveyance path 41, 51 Control unit 43 Image processing unit 511 Position control unit 512 Transport control unit 515 Correction processing Unit 60 image forming unit 601, 601 Y, 601 M, 601 C, 601 K image forming unit 611, 611 Y, 611 M, 611 C, 611 K LED writing unit 612, 612 Y, 612 M, 612 C, 612 K developing unit 61 , 613Y, 613M, 613C, 613K Photosensitive drum 614, 614Y, 614M, 614C, 614K Charging unit 616, 616Y, 616M, 616C, 616K Cleaning unit 620 Intermediate transfer unit 621 Intermediate transfer belt 622, 622Y, 622M, 622C, 622K Transfer roller 623 Secondary transfer roller 624 Belt cleaning device 630 Fixing unit 631 Heating roller 632 Pressure roller 633 Heating unit 81 Positioning detection unit 83 Temperature detection unit SC Document reading device P Paper

Claims (11)

A transport roller for transporting paper,
A colorimeter for measuring the color of the image formed on the paper;
A background member disposed opposite to the colorimeter;
A position control unit for controlling the position of at least one of the colorimeter and the background member within a range of a limit distance based on the physical properties of the paper;
The transport roller is
A first roller;
A second roller disposed opposite to the first roller ,
When pre-Symbol sheet is conveyed, it is freely adjust the distance between the background member and the colorimeter,
The position controller is
When the paper passes between the colorimeter and the background member,
Of the colorimeter and the background member,
Provided on the same side of the second roller and the paper;
Any one of the second roller being adjusted in a first direction away from the first roller according to the thickness of the paper while maintaining contact with the paper ,
Move in the same direction as the first direction according to the thickness of the paper ;
Image reading device. The physical properties of the paper are:
Stipulated based on the paper type of the paper,
The image reading apparatus according to claim 1. The position controller is
The one close to the second roller among the colorimeter and the background member is moved in the same direction as the first direction ,
The image reading apparatus according to claim 1. The second roller on the upstream side and the second roller on the downstream side are provided along the same side surface of the paper,
The position controller is
Of the colorimeter and the background member, those on the same side are moved in the same direction as the first direction ,
The image reading apparatus according to claim 1. The position of the gap between the colorimeter and the background member is
Adjusted on a nip line including a first nip formed on the upstream conveying roller and a second nip formed on the downstream conveying roller;
The image reading apparatus according to claim 4. The colorimeter is
A light source unit;
A light receiving optical system for receiving light including light reflected by the light emitted from the light source unit;
A spectroscopic optical system that outputs a spectroscopic spectrum from the light received by the light receiving optical system;
An arithmetic unit that calculates a colorimetric value based on the spectral spectrum output by the spectroscopic optical system,
The transport roller is
A plurality are provided along the conveyance direction of the paper,
Among the plurality of transport rollers, there are those arranged at positions along the reading center line of the light receiving optical system,
The image reading apparatus according to claim 4. The paper type of the paper is
Including at least one of thickness, basis weight, and material of the paper,
The image reading apparatus according to claim 2. The limit distance is
It is set in a range where the colorimetric accuracy of the colorimeter can be maintained,
The image reading apparatus according to claim 1. The first roller is
The paper is transported by driving force,
The second roller is
Forming a nip between the first roller and conveying the paper by following the driving of the first roller;
The image reading apparatus according to claim 1. A scanner for reading an image formed on the paper along the width direction of the paper;
A correction processing unit that corrects a reading result of the scanner based on a color measurement result of the colorimeter;
The image reading apparatus according to claim 1. The image reading apparatus according to any one of claims 1 to 10,
An image forming apparatus for forming an image on the paper,
Image forming system.

Images