JP2019186748A - Image reading device, image forming apparatus, post-processing device, and image forming system - Google Patents

Abstract

To provide an image reading device capable of highly accurately detecting an end surface of a paper sheet, while suppressing a cost, without reducing productivity and to provide an image forming apparatus, a post-processing device, and an image forming system.SOLUTION: An image reading device includes a detection part 93 which reads a color of a paper sheet P, a reference member 94 which is arranged at a position facing the detection part 93 through the paper sheet P, when the color of an end area including an end surface of the paper sheet P is read by the detection part 93, and a control part 300 which controls the position of the reference member 94. The reference member 94 includes a first opposing surface including a first color and a second opposing surface including a second color. When the end surface of the paper sheet P is detected by the detection part 93, the control part 300 arranges any one of the first opposing surface and the second opposing surface at the position facing the detection part 93 on the basis of a first color difference between the first color and a paper end neighboring color representing the color of the end area and a second color difference between the second color and the paper end neighboring color.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an image reading apparatus, an image forming apparatus, a post-processing apparatus, and an image forming system.

  Conventionally, in order to correct a deviation or skew of a conveyed sheet, the position of the end face of the sheet is detected. For example, by arranging a reference plate colored with a specific color at the focal position of the image sensor, the boundary between the sheet and the specific color is detected, and the boundary is set as the position of the end surface of the sheet. However, when reading a sheet on which an image having a reflection characteristic similar to that of the reference plate is read, the boundary between the sheet and the specific color cannot be detected, and there is a possibility that the end face of the sheet is erroneously detected. Therefore, by placing a reference plate, which is color-coded in white and black, at the focal position of the image sensor and moving the sheet between the image sensor and the reference plate, the white and black portions of the reference plate are Proposals have been made to read the sheet and detect the end face of the sheet (see, for example, Patent Document 1). In addition, there has been proposed one that detects the end face of a sheet while switching the colors of patterns such as black and white that are complementary to each other and conveying the sheet (for example, see Patent Document 2).

JP 2003-219117 A JP 2017-167302 A

  However, the conventional technology as described in Patent Document 1 moves the sheet to the respective positions of the white portion and the black portion of the reference plate, so that the sheet is fed twice in both the white portion and the black portion of the reference plate. Productivity is reduced because it needs to be read. In addition, in order to read the sheet without stopping the conveyance of the sheet, it is necessary to arrange a sensor that individually reads the white portion and the black portion of the reference plate. Therefore, the cost increases and the machine size also increases. On the other hand, the conventional technique as described in Patent Document 2 can detect the end face of the sheet while conveying the sheet, so there is no risk of reducing productivity, but the image formed on the sheet is considered. is not. Therefore, in order to detect the end face of the sheet with high accuracy even for various types of images formed on the sheet, each of the color of the image formed on the sheet and the white and black portions of the reference plate It is necessary to make a certain difference between colors. For example, it is necessary to increase time resolution or spatial resolution in a color pattern formed by white colored in the white portion of the reference plate and black colored in the black portion. Therefore, the conventional technique as described in Patent Document 2 is not likely to reduce the productivity, but may increase the cost.

  This indication is made in view of such a situation, and makes it possible to detect the end face of a sheet with high accuracy, suppressing cost, without reducing productivity.

  The image reading apparatus according to the first aspect of the present disclosure includes a detection unit that reads a color of a sheet, and the detection unit that detects the color of an end region including the end surface of the sheet through the sheet when the detection unit reads the color. A reference member disposed at a position facing the part, and a control unit for controlling the position of the reference member, wherein the reference member includes a first facing surface including a first color, and the first A second opposing surface including a second color different from the first color, and when the control unit detects the end surface of the sheet by the detection unit, the first color and the end region Based on the first color difference between the color near the sheet edge and the second color difference between the color near the sheet edge and the color near the sheet edge. Either one of the two facing surfaces is arranged at a position facing the detection unit.

  In addition, when the first color difference is larger than the second color difference, the control unit arranges the first facing surface at a position facing the detection unit, and the first color difference is the second color difference. When the color difference is equal to or less than the color difference, it is preferable that the second facing surface is disposed at a position facing the detection unit.

  In addition, when the color that occupies the end region is specified, the control unit determines that the color that occupies the end region is the color near the sheet end. It is preferable to determine.

  Further, it is preferable that the control unit determines an average color of a plurality of colors included in the end region as the color near the end of the sheet when the color that occupies the end region is not specified.

  In addition, when the difference between the color density included in a part of the end region and the color density included in another part of the end region is not within a certain range, the control unit It is preferable that an average color of a plurality of colors included in the partial area is determined as the color near the sheet edge.

  Further, the control unit is based on the color of the end region specified according to the arrangement position of the device arranged on at least one of the front side and the rear side of the detection unit and the processing content of the device, It is preferable to determine the color near the sheet edge.

  In addition, when the cutting unit that cuts at least a part of the sheet is disposed on the front side of the detection unit, the control unit corresponds to the sheet after being cut by the cutting unit. One of the first facing surface and the second facing surface is arranged at a position facing the detection unit based on the color near the edge of the sheet after cutting, which represents the edge region after cutting including the end surface of the sheet. Is preferable.

  Further, the control unit is based on the color of a pixel formed within a preset number of dots along the main scanning direction from the end surface of the sheet corresponding to a portion formed by being cut by the cutting unit. It is preferable that the color near the edge of the sheet after the cutting is determined.

  In addition, when the cutting unit that cuts at least a part of the sheet is disposed on the rear side of the detection unit, the control unit corresponds to the sheet before being formed by being cut by the cutting unit. Based on the color near the sheet end portion before cutting that represents the front end portion region including the end surface, either one of the first facing surface and the second facing surface is disposed at a position facing the detection portion. It is preferable.

  Further, the control unit is based on the color of a pixel formed within a preset number of dots along the main scanning direction from the end surface of the sheet corresponding to a portion before being formed by being cut by the cutting unit. It is preferable that the color near the edge of the sheet before cutting is determined.

  In addition, the image forming apparatus according to the second aspect of the present disclosure includes a detection unit that reads a color of a sheet, and when the color of an end region including the end surface of the sheet is read by the detection unit, A reference member disposed at a position facing the detection unit, wherein the reference member has a first facing surface including the first color and a second color different from the first color. And an image forming apparatus provided on the rear side of the own apparatus, wherein the detection unit detects the end face of the sheet and the first color. Based on the first color difference between the color near the sheet edge representing the color of the edge area and the second color difference between the color near the sheet edge and the color near the sheet edge. One of the surface and the second facing surface is disposed at a position facing the detection unit. Equipped with control unit, the.

  Therefore, as in the case of the image reading apparatus described above, it is possible to detect the end face of the sheet with high accuracy while suppressing cost without reducing productivity.

  In addition, the post-processing device according to the third aspect of the present disclosure includes a detection unit that reads a color of a sheet, and when the detection unit reads the color of an end region that includes the end surface of the sheet, A reference member disposed at a position facing the detection unit; and a control unit that controls a position of the reference member, wherein the reference member includes a first facing surface including a first color; A second facing surface including a second color different from the first color, and when the control unit detects the end surface of the sheet by the detection unit, the first color and the end Based on the first color difference between the color near the sheet edge representing the color of the partial area and the second color difference between the color near the sheet edge and the color near the sheet edge. Either one of the second facing surfaces is arranged at a position facing the detection unit.

  Therefore, as in the case of the image reading apparatus described above, it is possible to detect the end face of the sheet with high accuracy while suppressing cost without reducing productivity.

  The image forming system according to the fourth aspect of the present disclosure includes a detection unit that reads a color of a sheet, and when the color of an end region including the end surface of the sheet is read by the detection unit via the sheet. A reference member disposed at a position facing the detection unit; and a control unit that controls a position of the reference member, wherein the reference member includes a first facing surface including a first color; A second facing surface including a second color different from the first color, and when the control unit detects the end surface of the sheet by the detection unit, the first color and the end Based on the first color difference between the color near the sheet edge representing the color of the partial area and the second color difference between the color near the sheet edge and the color near the sheet edge. Either one of the second facing surfaces is arranged at a position facing the detection unit.

  Therefore, as in the case of the image reading apparatus described above, it is possible to detect the end face of the sheet with high accuracy while suppressing cost without reducing productivity.

  In the image forming system according to the fourth aspect of the present disclosure, the image forming system further includes a cutting unit that is arranged on a front side of the detection unit and cuts at least a part of the sheet, and the control unit includes the cutting unit. The first opposed surface and the second opposed surface based on the color near the edge of the sheet after cutting, which represents the edge region of the sheet after cutting including the edge of the sheet corresponding to the portion after being cut by It is preferable to arrange any one of them at a position facing the detection unit.

  Further, in the image forming system according to the fourth aspect of the present disclosure, the control unit is arranged in a main scanning direction of the detection unit from an end surface of the sheet corresponding to a portion after being cut and formed by the cutting unit. It is preferable to determine the post-cut sheet edge vicinity color based on the color of pixels formed within a preset number of dots formed along.

  In the image forming system according to the fourth aspect of the present disclosure, the image forming system further includes a cutting unit that is arranged on the rear side of the detection unit and cuts at least a part of the sheet, and the control unit includes the cutting unit. The first facing surface and the second facing surface of the first facing surface and the second facing surface based on the color near the edge portion before cutting representing the edge region before cutting that includes the edge surface of the sheet corresponding to the portion before being formed by cutting. It is preferable to arrange any one of them at a position facing the detection unit.

  Further, in the image forming system according to the fourth aspect of the present disclosure, the control unit is arranged in a main scanning direction of the detection unit from an end surface of the sheet corresponding to a portion before being formed by being cut by the cutting unit. It is preferable that the color near the edge of the sheet before cutting is determined based on the color of pixels formed within a preset number of dots.

  According to the first to fourth aspects of the present disclosure, it is possible to detect the end face of the sheet with high accuracy while suppressing cost without reducing productivity.

1 is a diagram illustrating an example of an overall configuration of an image forming system 1 according to an embodiment to which the present disclosure is applied. It is a figure explaining the usage example of the reference | standard member 94 which concerns on embodiment to which this indication is applied. It is a figure which shows an example of the waveform acquired by the detection part 93 which concerns on embodiment to which this indication is applied. 6 is a diagram illustrating an example of an end region P_sa of a sheet P in a case where a cutting unit 71 is disposed on a front side of a detection unit 93 according to an embodiment to which the present disclosure is applied. FIG. FIG. 8 is a diagram illustrating an example of an end region P_sa of a sheet P in a case where a cutting unit 71 is disposed on a rear stage side of a detection unit 93 according to an embodiment to which the present disclosure is applied. 10 is a flowchart for describing a control example according to an embodiment to which the present disclosure is applied. 10 is a flowchart illustrating an example of a paper edge vicinity color determination process according to an embodiment to which the present disclosure is applied.

  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.

  FIG. 1 is a diagram illustrating an overall configuration example of an image forming system 1 according to an embodiment to which the present disclosure is applied. FIG. 2 is a diagram illustrating a usage example of the reference member 94 according to the embodiment to which the present disclosure is applied. FIG. 3 is a diagram illustrating an example of a waveform acquired by the detection unit 93 according to the embodiment to which the present disclosure is applied. As shown in FIG. 1, the image forming system 1 includes a configuration in which post-processing devices 3 </ b> A to 3 </ b> C are connected to the rear side of the image forming device 2. That is, the image forming apparatus 2 has post-processing apparatuses 3A to 3C arranged on the rear side of the own apparatus. The post-processing device 3A is a device that performs a cutting process. The post-processing device 3B is a device that is arranged on the rear side of the post-processing device 3A and can perform image reading processing for reading the color of the paper P. The post-processing device 3C is a device that is arranged on the rear stage side of the post-processing device 3B and can perform a binding process. The post-processing device 3A may be disposed on the front side of the image forming apparatus 2, or may be disposed on the rear side of the post-processing device 3B. In addition, when any of post-processing apparatus 3A-3C is not specifically limited, each of post-processing apparatus 3A-3C is called the post-processing apparatus 3. The post-processing device 3A includes a cutting unit 71 and a control unit 200, and performs various post-processing on the paper P conveyed from the image forming apparatus 2. Details of the post-processing device 3A will be described later. The image forming apparatus 2 is an apparatus that forms an intermediate transfer type color image using electrophotographic process technology. The image forming apparatus 2 is a vertical tandem in which photosensitive drums corresponding to four colors of YMCK are arranged in series in the running direction of the intermediate transfer belt, that is, in the vertical direction, and the respective color toner images are sequentially transferred to the intermediate transfer belt in one procedure. The method is adopted. That is, the image forming apparatus 2 primarily transfers the Y (yellow), M (magenta), C (cyan), and K (black) toner images formed on the photosensitive drum to the intermediate transfer belt, and the intermediate transfer belt. After the four color toner images are superimposed on each other, the image is formed by secondary transfer onto the paper P.

  The image forming apparatus 2 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper transport unit 50, a fixing unit 60, and a control unit 100. The image reading unit 10 includes an automatic document feeder 11 and a document image scanning device 12. The automatic document feeder 11 is called an ADF (Auto Document Feeder). The automatic document feeder 11 transports the document placed on the document tray by the transport mechanism and sends it out to the document image scanning device 12. The automatic document feeder 11 can continuously read images of a large number of documents placed on a document tray. The automatic document feeder 11 can read both sides of each document by the paper reversing mechanism when continuously reading images of a large number of documents. The document image scanning device 12 optically scans a document conveyed on the contact glass from the automatic document feeder 11 or a document placed on the contact glass. The document image scanning device 12 reads the document image formed on the document by forming an image of reflected light from the document by optical scanning on the light receiving surface of the CCD sensor. The image reading unit 10 generates input image data of a document image based on the reading result by the document image scanning device 12. The input image data is supplied to the image processing unit 30, and the image processing unit 30 executes preset image processing. The operation display unit 20 is realized by, for example, a liquid crystal display (LCD) with a touch panel, and functions as the display unit 21 and the operation unit 22. The display unit 21 displays various operation screens, image states, operation states of functions, and the like according to display control signals input from the control unit 100. The operation unit 22 includes various operation keys such as a numeric keypad and a start key. The operation unit 22 generates an operation signal by receiving various input operations by the user. The operation signal is output to the control unit 100. The control unit 100 includes a CPU, a ROM, a RAM, a memory, and an I / O interface, and functions as a hardware processor.

  The image processing unit 30 includes a circuit that performs digital image processing according to initial settings or user settings on input image data. For example, under the control of the control unit 100, the image processing unit 30 performs gradation correction on input image data based on a gradation correction table in which gradation correction data is set. In addition to tone correction, the image processing unit 30 performs various correction processes such as color correction and shading correction, compression processes, and the like on the input image data. The image forming unit 40 performs various processes based on the input image data subjected to such various digital image processes. The image forming unit 40 forms an image using each color toner of Y component, M component, C component, and K component based on the input image data. The image forming unit 40 includes a photosensitive drum, a charging device, an exposure device, a developing device, and an intermediate transfer device. The surface of the photosensitive drum is uniformly charged by the corona discharge of the charging device. When the exposure device irradiates the photosensitive drum with laser light corresponding to the image of each color component, an electrostatic latent image of each color component is formed on the surface of the photosensitive drum. When the developing device supplies the toner of each color component to the surface of the photosensitive drum, the electrostatic latent image is visualized and a toner image is formed. The toner image is transferred onto the paper P by the intermediate transfer device. The fixing unit 60 fixes the toner image onto the paper P by heating and pressurizing the toner image transferred onto the paper P. The paper transport unit 50 includes a paper feed unit 51, a paper discharge unit 52, a transport path unit 53, and the like. The paper feeding unit 51 is accommodated for each type set in advance based on the basis weight, size, and the like of the paper P. The conveyance path unit 53 conveys the sheet P accommodated in the sheet feeding unit 51 or the sheet P on which an image is formed on either the front or back side. The paper discharge unit 52 discharges the paper P on which the image is formed to the outside of the apparatus.

  3 A of post-processing apparatuses are provided with the conveyance path switching part 72, the card tray 74, the purge tray 75, the waste box 76, and the conveyance path D1 in addition to the cutting part 71 and the control part 200. The control unit 200 includes a CPU, a ROM, a RAM, a memory, and an I / O interface, and functions as a hardware processor. Further, the post-processing device 3A is provided with various sensors for detecting passage or discharge of the paper P in each of the transport path D1 and the various paper discharge transport paths. A long paper transport path D2 is provided in the transport path D1. The long paper transport path D2 functions as a buffer when transporting long paper. The cutting unit 71 cuts at least a part of the paper P. In response to an instruction from the control unit 200, the cutting unit 71 cuts, for example, the top margin of the paper P. The cutting unit 71 includes at least one of a post-processing module 71A, a post-processing module 71B, a post-processing module 71C, and a post-processing module 71D. Each of the post-processing modules 71A to 71D can be detached from the post-processing device 3A, and the arrangement order can be changed as appropriate.

  The post-processing module 71A includes a slitter that cuts the paper P in the transport direction, that is, the sub-scanning direction. The post-processing module 71A cuts, for example, the top and bottom margins as the first margin of the paper P. The slitter of the post-processing module 71A functions as a top / bottom slitter when cutting the top / bottom margin. The post-processing module 71B may include, for example, a creasing section that performs creasing on the paper P cut by the post-processing module 71A. The post-processing module 71B may include a perforation portion that forms a perforation on the paper P cut by the post-processing module 71A. However, the post-processing module 71B need only be provided with a guide plate along the transport path D1 when the paper P is not subjected to processing such as a line insertion or perforation. The post-processing module 71C includes a slitter that cuts the paper P in the transport direction. The position where the slitter of the post-processing module 71C is arranged is different from the position where the slitter of the post-processing module 71A is arranged. The post-processing module 71C cuts out the paper P. The slitter of the post-processing module 71C functions as a dove cutting slitter when cutting dobbing. The post-processing module 71D includes a guillotine cutter that cuts the paper P cut by the post-processing module 71C in a direction orthogonal to the transport direction, that is, in the main scanning direction. The paper P cut in the main scanning direction by the post-processing module 71D is conveyed subsequently. Cutting the paper P in parallel with the transport direction is called FD (Feed Direction) cutting, and cutting the paper P in a direction orthogonal to the transport direction is called CD (Cross Direction) cutting. The FD cutting is performed by the post-processing modules 71A and 71C, and the CD cutting is performed by the post-processing module 71D. The transport path switching unit 72 switches to one of the respective paper discharge destinations depending on the transport destination of the paper P that has passed through the cutting unit 71. Each of the paper discharge destinations is connected to a paper discharge destination for transporting to the card tray 74, a paper discharge destination for transporting to the purge tray 75, a paper discharge destination for transporting chips to the waste box 76, and a rear stage side of the post-processing device 3A. There is a paper discharge destination that is transported to another device.

  The post-processing device 3B includes a detection unit 93, a reference member 94, and a control unit 300. The control unit 300 controls the position of the reference member 94, functions as an image reading device, and includes a conveyance direction. The color of the image formed on the sheet P is read while the sheet P is conveyed by the conveying unit 91 along K. The control unit 300 includes a CPU, a ROM, a RAM, a memory, and an I / O interface, and functions as a hardware processor. The detection unit 93 reads the color of the paper P, and can perform detection processing in conjunction with the paper detection unit 101 on the upstream side of the detection unit 93. The detection unit 93 is provided in a location where the light transmission member 930 is accommodated in the housing 931 and is opposed to the paper P at the focal position of the detection unit 93. The light transmission member 930 transmits the irradiation light applied to the paper P from the detection unit 93. The light transmitting member 930 transmits incident light including reflected light reflected from the paper P. The light transmitting member 930 also transmits incident light including the transmitted light of the paper P reflected from the reference member 94. In other words, the incident light to the light transmitting member 930 includes the reflected light reflected by the paper P without passing through the paper P, and the paper after being reflected by the reference member 94 after passing through the paper P. Transmitted light passing through P. In the detection unit 93, an illumination unit 934, a mirror unit 935, an imaging lens array 936, a light detection unit 937, and the like are housed in a housing 931 in addition to the light transmission member 930.

  The illumination unit 934 is provided inside and below the housing 931, and irradiates illumination light through the light transmissive member 930 by arranging the light transmissive member 930 at a protruding portion of the housing 931. The mirror unit 935 and the imaging lens array 936 constitute a reduction optical system, and guide incident light transmitted through the light transmission member 930 to the light detection unit 937. The light detection unit 937 is provided inside the housing 931 and above the illumination unit 934, and detects incident light. Specifically, the light detection unit 937 incorporates a solid-state imaging device such as a CCD or a CMOS, and detects the light emitted from the imaging lens array 936 by such a solid-state imaging device. The signal is converted into a signal, and the converted electric signal is output from an output terminal (not shown). More specifically, the solid-state imaging device is an imaging device that performs photoelectric conversion for each pixel. A plurality of solid-state imaging elements are arranged one-dimensionally in the width direction of the paper P, that is, in the main scanning direction, and are configured as a line image sensor. The detection unit 93 is configured such that the reading range of the plurality of solid-state imaging elements can read the maximum width of the paper P supplied from the image forming apparatus 2 or the like. The detection unit 93 repeats the reading operation of the image for one line extending in the width direction of the paper P in accordance with the paper passing operation of the paper P that passes through the focal position of the detection unit 93. The formed image is read as a two-dimensional image and used as a read value of the color of the image.

  As shown in FIG. 2, the reference member 94 includes a black surface I, a white surface II, a paper support surface III, a white reference surface IV, a black reference surface V, and a surface VI, and any of the surfaces is a light transmitting member. Opposite to 930. The black surface I supports the back side of the reading surface of the paper P when reading the outer shape of the paper P and the printing position of the image, and is the background of the paper P, and is formed in black. . The white surface II supports the back side of the reading surface of the paper P when reading the color of the image printed on the paper P, reflects reflected light transmitted through the paper P, and is white. Is formed. The paper support surface III supports the back side of the reading surface of the paper P when the paper P itself is not read, and is used only when the paper is passed. The white reference surface IV calibrates the reading color of the detection unit 93 and is formed with a white reference color. The black reference surface V is for detecting an adhering matter such as dust attached to the light transmission member 930 of the detecting unit 93, and is formed with a black reference color. That is, the white reference surface IV or the black reference surface V is not used for transporting the paper P, and is used for maintenance of the detection unit 93 such as calibration of the reading color or detection of attached matter. The surface VI is a surface facing the detection unit 93 at the home position when not operating. It should be noted that the reference member 94 does not have to be configured as all the above-described surfaces of the detection unit 93. The reference member 94 only needs to have at least a black surface I and a white surface II. The black surface I is a first facing surface including black as the first color. The white surface II is a second facing surface that includes a second color different from the first color. As shown in FIGS. 2 and 3, the reference member 94 is disposed at a position facing the detection unit 93 via the paper P when the color of the end region P_sa including the end surface of the paper P is read by the detection unit 93. The For example, as illustrated in FIG. 3, the detection unit 93 acquires different waveforms when black is read and when white is read. Therefore, since the portion where the waveform is switched between when reading black and when reading white is the end surface of the paper P, the end surface of the paper P is detected by switching the waveform acquired by the detection unit 93. be able to. However, depending on the color of the image formed on the paper P, it may be assumed that the waveform switching is not clear. Therefore, by changing the color of the reference member 94 to either black or white according to the color of the image formed on the paper P, the switching of the waveform acquired by the detection unit 93 is clarified. As shown in FIG. 3, the end region P_sa corresponds to a portion within a preset number of dots from the end surface of the paper P along the main scanning direction, for example, a portion within 5 dots. 5 dots is about 0.2 mm.

When the detection unit 93 detects the end surface of the paper P, the control unit 300 detects the first color difference ΔE ₀₀₁ ^* between the first color and the color near the paper edge representing the color of the edge region P_sa, and the second color. Based on the second color difference ΔE ₀₀₂ ^* between the color of the paper and the color near the edge of the sheet representing the color of the edge region P_sa, either the first facing surface or the second facing surface is detected by the detection unit 93. It is arranged at the position facing. More specifically, when the first color difference ΔE ₀₀₁ ^* is larger than the second color difference ΔE ₀₀₂ ^* , the control unit 300 arranges the first facing surface at a position facing the detection unit 93. When the first color difference ΔE ₀₀₁ ^* is equal to or smaller than the second color difference ΔE ₀₀₂ ^* , the control unit 300 arranges the second facing surface at a position facing the detection unit 93. The color difference ΔE ₀₀ ^* is obtained by the following expression (1).

The black color is (L ^* , a ^* , b ^* ) = (0, 0, 0), and the white color is (L ^* , a ^* , b ^* ) = (100, 0, 0). Here, if the color of the color near the edge of the sheet is green, the green color is (L ^* , a ^* , b ^* ) = (46, −52, 50). Therefore, the color difference ΔE ₀₀ ^* between black and green is 42.9 according to the equation (1). On the other hand, the color difference ΔE ₀₀ ^* between white and green is 48.8 according to the equation (1). As a result, since the one having the larger color difference ΔE ₀₀ ^* is the latter, it is preferable that the second facing surface including white is disposed to face the detection unit 93. Although an example in which the color near the paper edge is green has been described, the color near the paper edge is the scan data when the color is read by the detection unit 93 or the image forming apparatus 2 prints an image on the paper P. It is obtained from print data when forming. Specifically, when the edge region P_sa includes a plurality of colors and the color that occupies the end region P_sa is specified, the control unit 300 determines the color that occupies the end region P_sa as the vicinity of the sheet edge. Decide on the color. The color that occupies the end region P_sa most is the color that is most contained in the end region P_sa, that is, the color that has the largest area. Specifically, if the color that appears most frequently in the end region P_sa is counted. Good. On the other hand, when the color that occupies the edge region P_sa is not specified, the control unit 300 determines the average color of the plurality of colors included in the edge region P_sa as the color near the paper edge. Further, the control unit 300 determines that the difference between the color density included in a part of the end region P_sa and the color density included in another part of the end region P_sa is not within a certain range, When the density of the edge area P_sa is not constant, the average color of the plurality of colors included in the edge area P_sa is determined as the color near the paper edge.

  However, the end region P_sa varies depending on the type of post-processing. This will be specifically described with reference to FIGS. FIG. 4 is a diagram illustrating an example of the end region P_sa of the paper P when the cutting unit 71 is arranged on the front side of the detection unit 93 according to the embodiment to which the present disclosure is applied. FIG. 5 is a diagram illustrating an example of the edge region P_sa of the paper P when the cutting unit 71 is arranged on the rear side of the detection unit 93 according to the embodiment to which the present disclosure is applied. The control unit 300 is in the vicinity of the end of the sheet based on the arrangement position of the device arranged on at least one of the front side and the rear side of the detection unit 93 and the color in the end region P_sa specified according to the processing content of the device. Determine the color. Specifically, when the cutting unit 71 is arranged on the front side of the detection unit 93, the control unit 300 includes a post-cut end portion including an end surface of the paper P corresponding to a portion after being cut by the cutting unit 71. One of the first facing surface and the second facing surface is arranged at a position facing the detection unit 93 based on the color near the edge of the post-cut paper that represents the region P_Asa. On the other hand, when the cutting unit 71 is arranged on the rear side of the detection unit 93, the control unit 300 includes a cutting front end region including an end surface of the paper P corresponding to a portion before being formed by the cutting unit 71. One of the first facing surface and the second facing surface is arranged at a position facing the detection unit 93 based on the color near the edge of the sheet before cutting, which is representative of P_Bsa. More specifically, as shown in FIG. 5A, when the paper P after being cut by the cutting unit 71 is detected by the detection unit 93, the cutting unit 71 is used as shown in FIG. Based on the color of pixels formed within a preset number of dots along the main scanning direction from the end face of the paper P corresponding to the part after being cut and formed, a color near the paper edge after cutting is determined. . On the other hand, as shown in FIG. 4A, when the detection unit 93 detects the sheet P before being cut by the cutting unit 71, the sheet P is cut by the cutting unit 71 and formed as shown in FIG. 4B. Based on the color of the pixels formed within the preset number of dots along the main scanning direction from the end surface of the paper P corresponding to the portion before the cutting, the color near the paper edge before cutting is determined.

FIG. 6 is a flowchart illustrating a control example according to an embodiment to which the present disclosure is applied. In step S <b> 11, the control unit 300 performs a paper edge vicinity color determination process. Details of the paper edge vicinity color determination processing will be described later with reference to FIG. In step S <b> 12, the control unit 300 obtains a first color difference ΔE ₀₀₁ ^* between the first color and the color near the paper edge that represents the color of the edge area P_sa. In step S <b> 13, the control unit 300 obtains a second color difference ΔE ₀₀₂ ^* between the second color and the color in the vicinity of the paper edge that represents the color of the edge area P_sa. In step S <b ^> 14, the control unit 300 determines whether or not the first color difference ΔE ₀₀₁ ^* is greater than the second color difference ΔE ₀₀₂ ^* . When determining that the first color difference ΔE ₀₀₁ ^* is larger than the second color difference ΔE ₀₀₂ ^* (step S14; Y), the control unit 300 proceeds to the process of step S15. In step S15, the control unit 300 places the first facing surface at a position facing the detection unit 93, and proceeds to the process of step S16. When determining that the first color difference ΔE ₀₀₁ ^* is equal to or smaller than the second color difference ΔE ₀₀₂ ^* (step S14; N), the control unit 300 proceeds to the process of step S20. In step S20, the control unit 300 arranges the second facing surface at a position facing the detection unit 93, and proceeds to the process of step S16. In step S16, the control unit 300 determines whether printing has started. When determining that printing has started (step S16; Y), the controller 300 proceeds to the process of step S17. When determining that printing is not started (step S16; N), the control unit 300 continues the process of step S16. Whether or not printing is started may be determined by obtaining a control signal from the control unit 200 of the image forming apparatus 2. In step S <b> 17, the control unit 300 detects the end surface of the paper P. The detection of the end face of the paper P may be executed by the detection unit 93 as described above. In step S18, the control unit 300 corrects the misalignment of the paper P. Specifically, by transmitting the amount of deviation to the post-processing device 3C, the post-processing device 3C may correct the deviation or skew of the paper P. Although illustration is omitted, the post-processing device 3B may include a configuration for correcting the deviation or skew of the paper P. In step S19, the control unit 300 determines whether printing has ended. When the control unit 300 determines that the printing is finished (step S19; Y), the process of step S11 to step S20 is finished. When it is determined that the printing is not finished (step S19; N), the control unit 300 returns to the process of step S11. That is, the processing of step S11 to step S20 is executed for each sheet P.

  FIG. 7 is a flowchart illustrating an example of the paper edge vicinity color determination process according to the embodiment to which the present disclosure is applied. In step S31, the control unit 300 determines whether post-processing is executed. When determining that the post-processing is executed (step S31; Y), the control unit 300 proceeds to the process of step S32. When determining that the post-processing is not executed (step S31; N), the control unit 300 proceeds to the process of step S34. In step S32, the control unit 300 determines whether the post-processing is a cutting process. When determining that the post-processing is the cutting process (step S32; Y), the control unit 300 proceeds to the process of step S33. When determining that the post-processing is not the cutting process (step S32; N), the control unit 300 proceeds to the process of step S34. In step S <b> 33, the control unit 300 determines whether post-processing is executed on the upstream side of the detection unit 93. When the control unit 300 determines that the post-processing is to be executed on the upstream side of the detection unit 93 (step S33; Y), the control unit 300 proceeds to the process of step S37. In step S37, the control unit 300 stores, for each dot, the color of pixels formed within a preset number of dots along the main scanning direction from the position excluding the portion cut by post-processing, The process proceeds to S35. When the control unit 300 determines that the post-processing is not executed on the upstream side of the detection unit 93 (step S33; N), the control unit 300 proceeds to the process of step S34. In step S <b> 34, the control unit 300 stores the color of pixels formed within a preset number of dots along the main scanning direction from the end surface of the paper P for each dot, and proceeds to the process of step S <b> 35. In step S <b> 35, the control unit 300 determines whether or not the color that appears most frequently in the end region P_sa including the end surface of the paper P is uniquely specified. When the control unit 300 determines that the color that appears most frequently in the end region P_sa including the end surface of the paper P is uniquely identified (step S35; Y), the control unit 300 proceeds to the process of step S36. When the control unit 300 determines that the color that appears most frequently in the end region P_sa including the end surface of the paper P is not uniquely identified (step S35; N), the control unit 300 proceeds to the process of step S38. Note that the process of step S35 may be determined based on the color of the pixel stored by the process of step S34 or step S37. The color of the pixel stored by the process of step S34 or step S37 may be color information included in the pixel. In step S <b> 36, the control unit 300 determines the color that appears most frequently as the paper edge vicinity color, and ends the paper edge vicinity color determination process. In step S38, the control unit 300 determines the average color of the plurality of colors included in the edge region P_sa including the edge surface of the paper P as the paper edge vicinity color, and ends the paper edge vicinity color determination process.

From the above description, according to this embodiment, the first color difference ΔE ₀₀₁ ^* between the first color and the color near the paper edge, and the second color difference ΔE between the second color and the color near the paper edge. Based on ₀₀₂ ^* , one of the first facing surface and the second facing surface is arranged at a position facing the detection unit 93. Therefore, since the opposing surface is uniquely determined based on the color difference ΔE ₀₀ ^* , there is no need to use various combinations of color patterns. That is, it is not necessary to increase the time resolution or the spatial resolution in the color pattern of the opposite surface so that the end face of the paper P can be detected even for various types of images formed on the paper P. The cost required for the facing surface does not increase. Further, since the paper P between the facing surface determined based on the color difference ΔE ₀₀ ^* and the detection unit 93 is read, a certain difference is caused between the color of the facing surface and the color of the image formed on the paper P. Can be generated. Therefore, the end surface of the paper P can be detected with high accuracy. In addition, since the end surface of the paper P is detected on one of the two opposing surfaces, the end surface of the paper P can be detected while the paper P is being conveyed. Therefore, productivity is not reduced. Therefore, it is possible to detect the end face of the paper P with high accuracy while suppressing the cost without reducing the productivity.

Further, according to the present embodiment, when the first color difference ΔE ₀₀₁ ^* is larger than the second color difference ΔE ₀₀₂ ^* , the first facing surface is arranged at a position facing the detection unit 93. On the other hand, when the first color difference ΔE ₀₀₁ ^* is equal to or smaller than the second color difference ΔE ₀₀₂ ^* , the second facing surface is disposed at a position facing the detection unit 93. Therefore, the one with the larger color difference ΔE ₀₀ ^* is used as the facing surface. Therefore, since the color difference between the color of the facing surface and the color of the image formed on the paper P can be further generated, the end surface of the paper P can be detected particularly remarkably with high accuracy.

  Further, according to the present embodiment, when the color that occupies the edge region P_sa of the paper P is specified most, the color specified as the color that occupies the edge region P_sa of the paper P is determined as the color near the paper edge. Is done. Any color that occupies the end area P_sa of the paper P is appropriate as a representative color included in the end area P_sa of the paper P. Therefore, any one of the first color and the second color This is a reasonable comparison target. Therefore, the detection error of the end face of the paper P can be reduced.

  Further, according to the present embodiment, when the color that occupies the edge region P_sa of the paper P is not specified, the average value of a plurality of colors included in the edge region P_sa of the paper P is determined as the color near the paper edge. The Even if the color that occupies the end region P_sa of the paper P is not specified, the representative value included in the end region P_sa of the paper P is an average value of a plurality of colors included in the end region P_sa of the paper P. Since the target color is not off-target, it is not off-target as a comparison target with either the first color or the second color. Therefore, the detection error of the end surface of the paper P can be suppressed.

  Further, according to the present embodiment, the difference between the color density included in a part of the edge region P_sa of the paper P and the color density included in another part of the edge region P_sa of the paper P is constant. If it is not within the range, the average color of the plurality of colors included in the edge region P_sa of the paper P is determined as the color near the paper edge. Even if the color density of the edge area P_sa of the paper P is not constant, the representative value included in the edge area P_sa of the paper P is an average value of a plurality of colors included in the edge area P_sa of the paper P. Since the target color is not off-target, it is not off-target as a comparison target with either the first color or the second color. Therefore, the detection error of the end surface of the paper P can be suppressed.

  Further, according to the present embodiment, the color that occupies the end region P_sa of the paper P that is specified according to the arrangement position of the device arranged at least one of the front side and the rear side of the detection unit 93 and the processing content of the device. Based on this, the color near the paper edge is determined. Therefore, even if a change occurs in the end face of the paper P according to at least one of the devices before and after the detection unit 93, the color near the paper end is determined in consideration of the influence. Accordingly, since the color near the paper edge can be determined more accurately, the edge surface of the paper P can be detected more accurately.

  Further, according to the present embodiment, when the cutting unit 71 is arranged on the front side of the detection unit 93, the cut rear end region P_Asa corresponding to the portion formed by cutting by the cutting unit 71 is represented. One of the first facing surface and the second facing surface is arranged at a position facing the detection unit 93 based on the color near the edge of the sheet after cutting. Therefore, even if at least a part of the paper P is cut by the cutting unit 71, the facing surface is arranged based on the color near the paper edge after the cutting. Therefore, the end surface of the paper P can be accurately detected.

  Further, according to the present embodiment, the cutting unit 71 is arranged on the front side of the detection unit 93 and is formed along the main scanning direction from the end surface of the paper P corresponding to the portion formed by cutting by the cutting unit 71. Based on the color of the pixels formed within the preset number of dots, the post-cut end area P_Asa is determined. Therefore, since the post-cut end area P_Asa is determined by the number of dots from the end face of the paper P, the color of the image can be read by the detection unit 93 without error.

  Further, according to the present embodiment, when the cutting unit 71 is arranged on the rear stage side of the detection unit 93, the cutting front end region P_Bsa corresponding to the portion before being formed by cutting by the cutting unit 71 is represented. One of the first facing surface and the second facing surface is arranged at a position facing the detection unit 93 based on the color near the edge of the sheet before cutting. Therefore, before at least a part of the sheet P is cut by the cutting unit 71, the facing surface is arranged based on the color near the edge of the sheet before cutting. Therefore, the end surface of the paper P can be accurately detected.

  Further, according to the present embodiment, the cutting unit 71 is disposed on the rear stage side of the detection unit 93, and extends in the main scanning direction from the end surface of the paper P corresponding to the portion before being formed by being cut by the cutting unit 71. The cutting front end region P_Bsa is determined based on the color of the pixel formed within the preset number of dots. Therefore, since the pre-cut end area P_Bsa is determined by the number of dots from the end face of the paper P, the color of the image can be read by the detection unit 93 without error.

  As described above, the image forming system 1 to which the present disclosure is applied has been described based on the embodiment. However, the present disclosure is not limited to this, and may be changed without departing from the gist of the present disclosure.

For example, in the present embodiment, an example in which the image forming apparatus 2 forms an image on the paper P by the electrophotographic method has been described, but the present invention is not particularly limited thereto. For example, the image forming apparatus 2 may form an image on the paper P by another method in which heat is supplied to the paper P, such as an inkjet method or a thermal transfer method.
Further, in the present embodiment, an example has been described in which the reference member 94 is rotated to switch the surface facing the detection unit 93 configured in the reference member 94. However, the present invention is not limited thereto, and the reference member 94 is flat. A black plate I, a white plate II, a paper support surface III, a white reference plane IV, a black reference plane V, and a plane VI may be formed on the plane plate. When the reference member 94 is a flat plate, the black plate I, white surface II, paper support surface III, white reference surface IV, black reference formed on the reference member 94 are moved by moving the flat plate in parallel. What is necessary is just to switch to any one of the surface V and the surface VI.
Further, in the present embodiment, an example in which a portion within the preset number of dots from the end surface of the paper P along the main scanning direction corresponds to the end region P_sa has been described, but the present invention is not particularly limited thereto. Absent. For example, a portion within a preset number of dots from the end surface of the paper P along the sub-scanning direction may correspond to the end region P_sa. In this case, it is effective not to detect a portion along the transport direction of the paper P but to detect a portion along a direction orthogonal to the transport direction of the paper P.
In the present embodiment, the case where the sheet is a sheet has been described. However, a cloth, a resin film, or the like may be used as the sheet.

DESCRIPTION OF SYMBOLS 1 Image forming system, 100-300 Control part 2 Image forming apparatus, 10 Image reading part, 11 Automatic document feeder 12 Document image scanning apparatus, 20 Operation display part, 21 Display part, 22 Operation part 30 Image processing part, 40 Image forming section, 50 Paper transport section 51 Paper feed section, 52 Paper discharge section, 53 Transport path section, 60 Fixing section 3, 3A-3C Post-processing device 71 Cutting section, 71A, 71B, 71C, 71D Post-processing module 72 Transport Path switching section, 74 card tray, 75 purge tray, 76 waste box D1 transport path, D2 long paper transport path 91 transport section, 93 detection section, 930 light transmission member, 931 housing, 934 illumination section 935 mirror section, 936 connection Image lens array, 937 photodetection section, 94 reference member 101 sheet detection section P sheet, P_sa edge area P_Bsa edge area before cutting, P_Asa after cutting Edge area, K transport direction I black surface, II white surface, III paper support surface, IV white reference surface, V black reference surface VI surface ΔE ₀₀ ^* color difference, ΔE ₀₀₁ ^* first color difference, ΔE ₀₀₂ ^* second Color difference

Claims (17)

A detector that reads the color of the sheet;
When the color of the end region including the end surface of the sheet is read by the detection unit, a reference member disposed at a position facing the detection unit via the sheet;
A control unit for controlling the position of the reference member;
With
The reference member is
A first facing surface including a first color;
A second facing surface including a second color different from the first color;
With
The controller is
When the detection unit detects the end face of the sheet, the first color difference between the first color and the color near the sheet end representing the color of the end region, the second color, and the sheet end Based on the second color difference with the color near the portion, either one of the first facing surface and the second facing surface is disposed at a position facing the detection portion.
Image reading device. The controller is
When the first color difference is larger than the second color difference, the first facing surface is disposed at a position facing the detection unit,
When the first color difference is equal to or less than the second color difference, the second facing surface is disposed at a position facing the detection unit,
The image reading apparatus according to claim 1. The controller is
When the edge region includes a plurality of colors and the color that occupies the end region most is specified, the color that occupies the end region is determined as the color near the sheet end.
The image reading apparatus according to claim 1. The controller is
When the color that occupies the end region is not specified, an average color of a plurality of colors included in the end region is determined as the color near the sheet end.
The image reading apparatus according to claim 3. The controller is
If the difference between the color density contained in a part of the edge region and the color density contained in another part of the edge region is not within a certain range, a plurality of colors contained in the edge region Determining an average color of the colors near the edge of the sheet;
The image reading apparatus according to claim 1. The controller is
The sheet edge vicinity color is determined based on the color of the edge area specified according to the arrangement position of the apparatus arranged on at least one of the front side and the rear side of the detection unit and the processing content of the device. To
The image reading apparatus according to claim 1. The controller is
When a cutting section that cuts at least a part of the sheet is disposed on the front side of the detection section, a cutting rear end including an end surface of the sheet corresponding to a portion formed by cutting by the cutting section Based on the color near the edge of the sheet after cutting representing the partial area, either one of the first facing surface and the second facing surface is disposed at a position facing the detection unit.
The image reading apparatus according to claim 6. The controller is
Based on the color of the pixels formed within a preset number of dots along the main scanning direction from the end surface of the sheet corresponding to the part after being cut and formed by the cutting unit, the sheet end after cutting Determine neighboring colors,
The image reading apparatus according to claim 7. The controller is
When a cutting part that cuts at least a part of the sheet is disposed on the rear side of the detection unit, the cutting front end part includes an end surface of the sheet corresponding to a part before being cut by the cutting part and formed. Based on the color near the edge of the sheet before cutting representing the region, either one of the first facing surface and the second facing surface is disposed at a position facing the detection portion.
The image reading apparatus according to claim 6. The controller is
Based on the color of pixels formed within a preset number of dots along the main scanning direction from the end surface of the sheet corresponding to the portion before being formed by cutting by the cutting unit, the sheet end before cutting Determine neighboring colors,
The image reading apparatus according to claim 9. A detector that reads the color of the sheet;
When the color of the end region including the end surface of the sheet is read by the detection unit, a reference member disposed at a position facing the detection unit via the sheet;
With
The reference member is
A first facing surface including a first color;
A second facing surface including a second color different from the first color;
An image forming apparatus in which an image reading apparatus including
When the detection unit detects the end face of the sheet, the first color difference between the first color and the color near the sheet end representing the color of the end region, the second color, and the sheet end A control unit that arranges one of the first facing surface and the second facing surface at a position facing the detection unit, based on a second color difference with a color near the portion,
Comprising
Image forming apparatus. A detector that reads the color of the sheet;
When the color of the end region including the end surface of the sheet is read by the detection unit, a reference member disposed at a position facing the detection unit via the sheet;
A control unit for controlling the position of the reference member;
With
The reference member is
A first facing surface including a first color;
A second facing surface including a second color different from the first color;
With
The controller is
When the detection unit detects the end face of the sheet, the first color difference between the first color and the color near the sheet end representing the color of the end region, the second color, and the sheet end Based on the second color difference with the color near the portion, either one of the first facing surface and the second facing surface is disposed at a position facing the detection portion.
Post-processing device. A detector that reads the color of the sheet;
When the color of the end region including the end surface of the sheet is read by the detection unit, a reference member disposed at a position facing the detection unit via the sheet;
A control unit for controlling the position of the reference member;
With
The reference member is
A first facing surface including a first color;
A second facing surface including a second color different from the first color;
With
The controller is
When the detection unit detects the end face of the sheet, the first color difference between the first color and the color near the sheet end representing the color of the end region, the second color, and the sheet end Based on the second color difference with the color near the portion, either one of the first facing surface and the second facing surface is disposed at a position facing the detection portion.
Image forming system. A cutting unit that is arranged on the front side of the detection unit and cuts at least a part of the sheet;
Further comprising
The controller is
The first facing surface and the second surface are based on the color near the edge of the post-cut sheet representing the post-cut end area including the end face of the sheet corresponding to the portion formed by being cut by the cut section. Any one of the facing surfaces of the is disposed at a position facing the detection unit,
The image forming system according to claim 13. The controller is
Based on the color of pixels formed within a preset number of dots formed along the main scanning direction of the detection unit from the end face of the sheet corresponding to the portion after being cut and formed by the cutting unit. , Determine the color near the edge of the sheet after cutting,
The image forming system according to claim 14. A cutting unit that is arranged on the rear side of the detection unit and cuts at least a part of the sheet;
Further comprising
The controller is
Based on the pre-cut sheet edge vicinity color representing the pre-cut end area including the end face of the sheet corresponding to the portion before being cut by the cut section, the first facing surface and the second face Arranging either one of the opposed surfaces at a position facing the detection unit,
The image forming system according to claim 13. The controller is
Based on the color of pixels formed within a preset number of dots along the main scanning direction of the detection unit from the end surface of the sheet corresponding to a portion before being formed by the cutting unit. Determine the color near the front sheet edge,
The image forming system according to claim 16.