JP2006224537A - Image forming apparatus and method for controlling it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that conveys a printed material subjected to processing of printing an original image by discriminating its conveyance destinations depending on whether the color tone of the original image is faithfully represented on the printed material, and automatically performs adequate correction so as to faithfully represent the color tone of the printed material with respect to the original image, and also to provide a method of controlling it. <P>SOLUTION: This image forming apparatus comprises: an original image data accumulation means for accumulating original image data to be subjected to the processing of printing; a reading means for optically reading an image on a printed material printed by the processing of printing; a comparison means for comparing the read image data read by the reading means with the original image data accumulated by the original image data accumulation means; and a discharge control means that discharges the printed material to a first discharge hole when a difference between the read image data and the original image data is in an allowable range according to the compared result by the comparison means or to a second discharge hole when the difference is out of the allowable range. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and a control method therefor, and in particular, a transport destination of a printed material depending on whether or not the color tone of the printed material obtained by printing the original image data is faithfully reproduced with respect to the original image data. The present invention relates to an image forming apparatus and a control method for automatically performing appropriate correction so that the color tone of a printed material is faithfully reproduced with respect to original image data.

  In recent years, with the development of DTP (= DeskTop Publishing), image data that has been designed may be confirmed (calibrated) by a third party other than the data creator.

  When color image data is output by a color printing apparatus, the image quality of the output printed matter may be output different from the intention of the data producer.

  Conventionally, when checking the image quality when color image data is output from a color printing device, calibrate the color printing device that can be calibrated, and then check the image quality of the printed matter output from the color printing device. However, if the confirmation result is good, a method of printing out may be used.

  However, in such a method, when there is dissatisfaction with the image quality of the printed matter output from the color printing apparatus, the calibration and the visual confirmation of the printed matter after the calibration are output before the satisfactory printed matter is output. Therefore, it is troublesome for the operator to be restrained by the operation of the apparatus and the confirmation work during that time.

  In addition, there may be individual differences in the image quality judgment by visual confirmation of the printed matter. However, the fact that the quality of the printed matter is clearly and automatically performed is considered to be an operation of the apparatus and a confirmation work for the operator. Therefore, it is desirable to provide such an apparatus and a control method.

For example, Patent Document 1 proposes an image forming apparatus that can eliminate the difference as much as possible when there is a tendency that an output image is not faithfully reproduced with respect to a document image.
JP 2002-290758 A

  By the way, the proposal shown in the above-mentioned patent document 1 applies predetermined image processing to image data obtained by optically reading a document image, and forms an output image on a sheet using the image data after the image processing. More specifically, the first image data obtained from the original image is stored, and the first image data obtained from the output image formed on the paper using the first image data is configured. The second image data is stored, the first image data and the second image data are compared, and the image processing is performed so that a difference between the first image data and the second image data is reduced. Is to change.

  However, in the image forming apparatus proposed in Patent Document 1, the user makes a judgment as to whether or not the output image has a tendency to be not faithfully reproduced with respect to the document image by visual confirmation. When the user determines that the output image has a tendency not to be faithfully reproduced, the image quality correction is instructed through the operation panel so that the difference between the first image data and the second image data is reduced. The image processing is changed.

  Therefore, the present invention distinguishes and conveys the destination of the printed material according to whether or not the color tone of the printed material obtained by printing the original image data is faithfully reproduced with respect to the original image data. It is an object of the present invention to provide an image forming apparatus that automatically performs appropriate correction so that color tone is faithfully reproduced with respect to original image data, and a control method therefor.

  In order to achieve the above object, an invention according to claim 1 is an image forming apparatus that performs print processing based on original image data, and includes original image data storage means for storing the original image data to be printed, and the print processing. A reading unit that optically reads an image of a printed product, and a comparison that compares read image data read by the reading unit with original image data corresponding to the read image data stored in the original image data storage unit And when the difference between the read image data and the original image data is within a preset allowable range based on a comparison result by the comparison unit, the printed matter is discharged to the first discharge port, and the predetermined allowable range is set. And a discharge control means for discharging the printed matter to the second discharge port.

  Further, in the invention of claim 2, in the invention of claim 1, when the difference between the read image data and the original image data is outside a preset allowable range due to a comparison result by the comparison means, The image processing apparatus further includes a correction unit that corrects the image data based on the read image data, and a reprint control unit that performs reprinting based on the corrected image data corrected by the correction unit.

  According to a third aspect of the present invention, there is provided an image forming apparatus that performs a printing process based on original image data, an original image data storage unit that stores the original image data to be subjected to the printing process, and a printed matter printed by the printing process. Reading means for optically reading an image; comparison means for comparing read image data read by the reading means with original image data corresponding to the read image data stored in the original image data storage means; and the comparison When the difference between the read image data and the original image data is within a preset allowable range based on a comparison result by the means, the printed matter is discharged to the first discharge port, and is outside the preset allowable range Is a difference between the read image data and the original image data according to a comparison result by the discharge control means for discharging the printed matter to the second discharge port and the comparison means. A correction unit that corrects the original image data based on the read image data, and a reprint control unit that performs reprinting based on the corrected image data corrected by the correction unit when it is outside a preset allowable range; It is characterized by doing.

  According to a fourth aspect of the present invention, in the control method for an image forming apparatus that performs a printing process based on original image data, the original image data to be printed is accumulated by an original image data accumulating unit, and is printed by the printing process. The printed image is optically read by the reading means, and the read image data read by the reading means is compared with the original image data corresponding to the read image data stored in the original image data storage means by the comparison means. If the difference between the read image data and the original image data is within a preset allowable range by the discharge control unit based on the comparison result by the comparison unit, the printed matter is discharged to the first discharge port and set in advance. If it is outside the allowable range, the printed matter is discharged to the second discharge port.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, when the difference between the read image data and the original image data is outside a preset allowable range due to the comparison result by the comparison means, the correction means Then, the original image data is corrected based on the read image data, and the corrected image data corrected by the correction unit is reprinted by the reprint control unit.

  According to a sixth aspect of the present invention, in the control method of an image forming apparatus that performs a printing process based on original image data, the original image data to be printed is accumulated by an original image data accumulating unit, and is printed by the printing process. The printed image is optically read by the reading means, and the read image data read by the reading means is compared with the original image data corresponding to the read image data stored in the original image data storage means by the comparison means. If the difference between the read image data and the original image data is within a preset allowable range by the discharge control unit based on the comparison result by the comparison unit, the printed matter is discharged to the first discharge port and set in advance. If it is out of the allowable range, the printed matter is discharged to the second discharge port, and the read image data and the previous image data are compared with the result of comparison by the comparison means. When the difference from the original image data is outside a preset allowable range, the correction unit corrects the original image data based on the read image data, and the correction image data corrected by the correction unit is corrected by the reprint control unit. Reprinting is performed.

  According to the image forming apparatus and the control method of the present invention, the transport destination of the printed material is determined depending on whether the color tone of the printed material obtained by printing the original image data is faithfully reproduced with respect to the original image data. Since they are conveyed separately, it is possible to easily distinguish a printed matter having a good color tone from one that is not.

  In addition, the printed material on which the original image data is printed by the printing process is automatically conveyed to a reading device that reads the image of the printed material, and the color tone of the image data of the printed material read by the reading device and the original image data corresponding to the image data is read. It is determined whether or not the difference of the original image exceeds the allowable range, and if it exceeds the allowable range, the original image data is subjected to appropriate correction so as not to exceed the allowable range and reprinted. Even if the operation is performed a plurality of times until the color tone of the printed matter obtained by printing the data is faithfully reproduced with respect to the original image data, there is an effect that the operator's hand is not bothered. .

  Hereinafter, an example of an image forming apparatus according to the present invention and an apparatus to which the control method thereof is applied will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a functional configuration of a multifunction peripheral 100 to which an image forming apparatus and a control method thereof according to the present invention are applied, and a configuration illustrating a main part of the overall configuration in which the multifunction peripheral 100 and the client PC 10 are connected. FIG.

  In FIG. 1, solid arrows indicate the flow of control data and image data, and broken arrows indicate the flow of paper or printed matter.

  As illustrated in FIG. 1, the multifunction peripheral 100 includes a CPU (= Central Processing Unit) 20, an external interface unit 30, an image reading unit 40, an image processing unit 50, and an image data storage unit 60. An image forming unit 70, a transport mechanism 80, a user interface unit 90, a paper discharge tray A93, and a paper discharge tray B94.

  The multifunction device 100 is connected to the client PC 10 via the network 95, and the multifunction device 100 performs a printing function as a color printing apparatus that performs color printing on a sheet of color image data instructed by the user from the client PC 10. And a copying function as a color copying machine that reads an image of a printed matter (original) placed on the platen glass 2 (see FIG. 2) of the multifunction peripheral 100 and prints the read image on a sheet.

  The printing function of the multifunction peripheral 100 as a color printing apparatus mainly functions by processing operations of the image processing unit 50 and the image forming unit 70, and the copying function as a color copying machine mainly functions as the image reading unit 40. The image processing unit 50 and the image forming unit 70 are configured to function by processing operations.

  The client PC 10 is a computer such as a so-called personal computer provided with an input device, a storage device, a display device, a central processing unit, and the like.

  Data signals and control signals are transmitted and received between the CPU 20 of the multifunction peripheral 100 and each unit and each interface via the bus 21. The CPU 20 controls each part and each interface of the multifunction peripheral 100 to control the entire multifunction peripheral 100. Take overall control.

  The external interface 30 transmits / receives data and control signals to / from the client PC 10 and the multifunction peripheral 100 connected to the network 95 and other external devices (hereinafter collectively referred to as “external devices”).

  The image reading unit 40 is a so-called image scanner device, which projects light on the surface of a printed material placed on the platen glass 2 of the multifunction machine 100, receives the reflected light, converts it into image data, and prints the printed material. Image data corresponding to the image is generated.

  The image processing unit 50 performs predetermined image processing on the image data read from the printed matter by the image reading unit 40 or the image data transferred from the client PC 10 or the like connected to the network 95.

  The image data storage unit 60 stores and holds image data generated by performing predetermined image processing in the image processing unit 50.

  The image forming unit 70 forms on the paper the image data output by the image processing by the image processing unit 50, and outputs the printed matter.

  The transport mechanism 80 transports, to the image forming unit 70, a sheet on which the image forming unit 70 forms predetermined image processing on the sheet based on a command signal from the CPU 20. In other words, the printed matter formed and output on the sheet by the image forming unit 70 is conveyed to the image reading unit 40, the discharge tray A93, and the discharge tray B94.

  The user interface 90 includes an operation unit such as a button for performing various setting operations and various process selection operations by a user operation, a display screen display unit, and the like, and desired information display is performed by the user operating the operation unit. And print output selection operation.

  The paper discharge tray A93 and the paper discharge tray B94 accumulate and store printed materials conveyed by the conveyance mechanism 80.

  In the present embodiment, FIG. 1 shows an example in which a multifunction peripheral 100 having a color printing function and a color copying function is assumed. However, the color printing apparatus and the color copying apparatus are configured independently of each other. Alternatively, a configuration in which the devices are combined, or a configuration in which the color printing device and the color image scanner device are independently configured, and a configuration in which these devices are controlled may be employed.

  FIG. 2 is a configuration diagram illustrating a detailed configuration of the multifunction peripheral 100.

  As shown in FIG. 2, the image reading unit 40 (a portion surrounded by a broken line) of the multifunction device 100 is printed by the printed material 1 or the transport mechanism 80 placed on the platen glass 2 disposed on the upper portion of the multifunction device 100. A light source lamp 41 that projects light onto the surface of the printed material 4 that is conveyed on the platen glass 2 at a predetermined conveyance speed, and a reflected light from the surface of the printed material 1 or the printed material 4 that is projected from the light source lamp 41 is photoelectrically generated. The first reflecting mirror 42, the second reflecting mirror 43, and the third reflecting mirror 44 that guide to the conversion element 46 (CCD = Charge Couple Device) are disposed between the third reflecting mirror 44 and the photoelectric conversion element 46, and A conjugating lens 45 that images reflected light from the three reflecting mirrors 44, a photoelectric conversion element 46 that converts the received light into an electrical signal corresponding to the received light, and an analog electric power output from the photoelectric conversion element 46 And an A / D converter 47 for converting the air signal into a digital signal.

  The photoelectric conversion element 46 outputs an analog signal having an output level corresponding to the amount of received light of each color of red (R), green (G), and blue (B).

  The light source lamp 41, the first reflecting mirror 42, the second reflecting mirror 43, the third reflecting mirror 44, the conjugating lens 45, the photoelectric conversion element 46, and the A / D converter 47 of the image reading unit 40 are integrated. When the image of the printed matter 1 placed on the platen glass 2 is read, the image is read in the sub-scanning direction. When the image reading unit 40 reads the image of the printed material 1 by moving the reading unit 40 and reads the image of the printed material 4 conveyed on the platen glass 2 by the conveyance mechanism 80, the image reading unit 40 in the sub-scanning direction. The printed material 4 is moved on the platen glass 2 at a predetermined conveying speed by the conveying mechanism 80 without moving the image, and the image of the printed material 4 is read by the image reading unit 40.

  The platen cover 3 of the multifunction peripheral 100 presses the printed material 1 on the platen glass 2 and efficiently reflects the light projected from the light source lamp 41.

  The image processing unit 50 is a functional block of an image data generation unit 51, a color conversion unit 52, a color conversion unit 53, a color correction unit 54, a gradation correction unit 55, and a screen processing unit 56. The image data generation unit 51 interprets the page description language transferred from the client PC 10 or the like connected via the network 95 and generates RGB (color space) image data (RGB). .

  The color conversion unit 52 converts the image data (RGB) generated and output by the image data generation unit 51 into image data (L * a * b *) in a uniform color space (L * a * b *).

  The color conversion unit 53 scans the printed material 1 or the printed material 4 with the image reading unit 40 and reads the RGB image data (RGB) into the image data (L * a * b *) in the uniform color space (L * a * b *). *).

  The color correction unit 54 converts the image data (L * a * b *) output from the color conversion unit 52 or the color conversion unit 53 to yellow (Y), magenta (M), cyan (C), black of the multifunction peripheral 100. (K) (hereinafter collectively referred to as “YMCK”) is converted into image data (YMCK) of 4 original color materials each having 8 bits, and color correction is performed.

  The gradation correction unit 55 performs gradation correction on the image data (YMCK) generated by the color correction unit 54.

  The screen processing unit 56 performs screen processing on the image data (YMCK) that has been subjected to gradation correction by the gradation correction unit 55.

  The image data storage unit 60 stores and holds the image data that has been subjected to predetermined image processing by the image processing unit 50 as described above.

  Specifically, for example, image data in a uniform color space (L * a * b *) generated by converting image data transferred in response to a print instruction from the client PC 10 or the like by the color conversion unit 52 of the image processing unit 50. And image data (L * a * b *) in a uniform color space generated by converting the image data (RGB) read from the printed material 1 or the printed material 4 by the image reading unit 40 by the color converting unit 52. .

  The image forming unit 70 generates a pulse signal based on the image data output by the screen processing from the image processing unit 50, and the photoreceptors 76Y to 76K based on the pulse signal generated by the pulse generating unit 71. An exposure control unit 72 that controls exposure devices 73Y to 73K that perform exposure of laser light that is exposed upward, and charging devices 74Y to 74K that charge the surfaces of the photoreceptors 76Y to 76K to a predetermined polarity (for example, negative polarity) in advance. The latent images formed on the surfaces of the photoreceptors 76Y to 76K by the exposure of the laser light are developed with yellow (Y), magenta (M), cyan (C), and black (K) color toners to obtain color toners. Color toner images formed on the photoconductors 76Y to 76K, which are disposed below the photoconductors 76Y to 76K and developing devices 75Y to 75K that form images. An intermediate transfer member 78 for transferring the, and a fixing device 712 for fixing the color toner image transferred from the intermediate transfer member 78 onto the paper 92 which is transported and fed from the paper feed tray 91.

  The intermediate transfer body 78 is supported by a drive roll 711b, a driven roll 79, and primary transfer rolls 77Y to 77K, and the drive roll 711b is a roll facing the driven roll 79 and the pressure roll 711a. The toner image transferred onto the intermediate transfer body 78 is transferred onto the sheet 92 at a predetermined timing by the drive roll 711b rotating in the direction of the arrow in the drawing with the photosensitive bodies 76Y to 76K at a peripheral speed. The

  The primary transfer rolls 77Y to 77K are arranged to face the respective photoconductors 76Y to 76K and are formed on the respective photoconductors 76Y to 76K. Yellow (Y), magenta (M), cyan (C), black (K) All or part of the four colors of toner images are transferred to the intermediate transfer body 78 in a state of being sequentially overlapped, and the drive roll 711b is also transferred as a secondary transfer roll by being sequentially overlapped. Is transferred onto the sheet 92 by applying a bias having a polarity opposite to the frictional charge of the toner.

  The paper 92 is picked up from the paper feed tray 91 on the carry-in side (the driven roll 79 side) on which the uppermost paper 92 among the plurality of papers stored and stored in the paper feed tray 91 is carried into the intermediate transfer body 78. Pickup roll 713 and registration rolls 714 a and 714 b for temporarily stopping paper 92 fed from pickup roll 713 and feeding paper 92 to the carry-in side of intermediate transfer body 78 in accordance with the printing start timing of intermediate transfer body 78 are installed. Yes.

  A paper guide (not shown) for guiding the paper 92 to be conveyed is provided on the path from the pickup roll 713 to the intermediate transfer body 78.

  The transport mechanism 80 includes a mechanism for transporting the paper 92 accumulated and stored in the paper feed tray 91 to the carry-in side (the driven roll 79 side) that is carried into the intermediate transfer body 78 of the image forming apparatus 70, and the image forming unit 70. The image forming unit 70 is a transport mechanism including a mechanism for transporting the printed matter formed and output to the image reading unit 40, the paper discharge tray A93, and the paper discharge tray B94. When reading the image of the printed matter 4 formed and output on the image reading unit 40, the image reading unit 40 reads the image of the printed matter 4 on the platen glass 2 disposed on the upper part of the multifunction peripheral 100 so that the image reading unit 40 reads the image. The image reading unit 40 reads the image data (RGB) transferred from the client PC 10 or the like and the image reading unit 40 from the printed material 4. If the difference in color tone between the image data (L * a * b *) and the image data (L * a * b *) obtained by color-converting the image data (RGB), respectively, exceeds the allowable range, the printed matter 4 is removed from the paper discharge tray B94. If it does not exceed the allowable range, it is transported to the discharge tray A93.

  In addition, the image data (RGB) transferred in response to a print instruction from the client PC 10 or the like is subjected to image processing and printed out, or image data read from the printed material 1 placed on the platen glass 2 of the multifunction peripheral 100. When a normal copying process is performed in which (RGB) is subjected to image processing and printed out, the printed matter formed by the image forming unit 70 on which the image data is formed on the paper is conveyed to the paper discharge tray A93.

  The paper feed tray 91, the paper discharge tray A93, and the paper discharge tray B94 may be configured to store and store a plurality of types of paper sizes or printed materials.

By the way, the multifunction peripheral 100 according to the present invention performs predetermined image processing on image data (referred to as “original image data” for convenience of explanation) transferred upon receiving a print instruction from the client PC 10 or the like. The output image formed on the sheet is compared with image data (for convenience of explanation, referred to as “read image data”) read by the image reading device, and the difference in color tone between the two image data falls within a predetermined allowable range. Depending on whether or not it exceeds, the transport destination of the printed matter on which the output image is formed is distinguished and transported.
In addition, when the difference in color tone between the original image data and the read image data exceeds the allowable range, a correction function is provided to correct the difference so as not to exceed the allowable range by reducing the difference.

  Operation control of these functions is mainly performed by the CPU 20 of the multifunction peripheral 100.

  FIG. 3 is a block diagram illustrating a functional configuration of the CPU 20.

  As shown in FIG. 3, the CPU 20 includes a control unit 201, a conveyance control unit 202, a comparison determination unit 203, a correction unit 204, and a memory 205. The control unit 201 includes each unit 202 of the CPU 20, 203, 204, 205 and the entire MFP 100 are controlled in an integrated manner.

The transport control unit 202 transports the paper 92 stored and stored in the paper feed tray 91 to the image forming unit 70 by the transport mechanism 80, or image data after image processing is formed on the paper and output from the image forming unit 70. The printed product 4 is conveyed to the paper discharge tray A93, or on the platen glass 2 disposed on the upper part of the multifunction peripheral 100 so that the image reading unit 40 can read the image of the printed product 4 output from the image forming unit 70. Transport the printed matter 4 output from the image forming unit 70 onto the platen glass 2 at the top of the multifunction peripheral 100 and then transport it to the transport mechanism 80 so as to transport it to the discharge tray A93 or the discharge tray B94. Direct control.
The comparison determination unit 203 compares the original image data (L * a * b *) stored and held in the image data storage unit 60 with the read image data (L * a * b *) read from the printed material 4. Then, it is determined whether or not the difference in color tone between the two image data exceeds the allowable range and output.

  Based on the determination result of the comparison determination unit 203, the correction unit 204 has a difference in color tone between the original image data (L * a * b *) and the read image data (L * a * b *) exceeding an allowable range. In this case, corrected image data (L * a * b *) corrected so as to reduce the difference is generated.

  The memory 205 stores various data and various control programs.

  Based on the control of the CPU 20 configured as described above, the processing operation of the main part of the multifunction peripheral 100 according to the present invention will be described in detail with reference to the flowchart of FIG.

  As shown in FIG. 4, when the user selects image data to be printed out on a screen (not shown) of the client PC 10 and clicks the start button, the original image data is transferred from the client PC to the multifunction peripheral 100 ( Step S401).

  The original image data transferred to the multi-function device 100 is transferred to the image processing unit 50 via the external interface 30 of the multi-function device 100, and subjected to predetermined image processing (step S402).

  Specifically, the original image data transferred to the image processing unit 50 is transferred to the image data generation unit 51, and the image data generated by the image data generation unit 51 from the client PC 10 is converted into RGB (color space) image data. Convert to (RGB).

  The original image data (RGB) generated by the image data generation unit 51 is converted into image data (L * a * b *) in the uniform color space (L * a * b *) by the color conversion unit 52 and converted. The original image data (L * a * b *) is stored and held in the image data storage unit 60 and is transferred to the color correction unit 54 of the image processing unit 50.

  The original image data (L * a * b *) transferred to the color correction unit 54 is processed by the color correction unit 54 with yellow (Y), magenta (M), cyan (C), black (K) ( YMCK) is converted into image data (YMCK) of 4 original color materials each having 8 bits, and color correction is performed.

  The color-corrected original image data (YMCK) is transferred to the gradation correction unit 55, and the original image data (YMCK) is subjected to gradation correction by the gradation correction unit 55 and then transferred to the screen processing unit 56. The screen is processed and transferred to the image forming unit 70.

  The image data subjected to the image processing as described above and transferred from the image processing unit 50 is formed and output on the sheet 92 conveyed from the paper feed tray 91 by the conveyance mechanism 80 in the image forming unit 70. (Step S403).

  The printed matter 4 formed by outputting image data after image processing on the paper 92 by the image forming unit 70 is output to the upper part of the multifunction peripheral 100 by the conveyance control of the conveyance mechanism 80 based on the command signal of the conveyance control unit 202 of the CPU 20. It is conveyed on the arranged platen glass 2 (step S404), and the image of the conveyed printed matter 4 is read by the image reading unit 40 (step S405).

  The image data (read image data) of the printed matter 4 read by the image reading unit 40 is transferred to the color conversion unit 53 of the image processing unit 50, and the color conversion unit 53 converts the read image data (RGB) into an image in a uniform color space. Convert to data (L * a * b *).

  The read image data (L * a * b *) generated by the color conversion unit 53 is stored and held in the image data storage unit 60, and the comparison / determination unit 203 of the CPU 20 is stored and held in the image data storage unit 60. The original image data (L * a * b *) and the read image data (L * a * b *) are compared (step S406), and the color tone difference between the two image data (L * a * b *) It is determined whether or not exceeds the allowable range (step S407).

  Specifically, whether or not the difference in color tone between the original image data (L * a * b *) and the read image data (L * a * b *) exceeds the allowable range is determined based on the original image data ( Color difference (dL *, da *) between each L * a * b * value of (L * a * b *) and each L * a * b * value of the read image data (L * a * b *) , Db *), and whether the calculated color differences (dL *, da *, db *) are within a predetermined allowable range value (ΔL *, Δa *, Δb *) is determined.

  The color difference (dL *, da *, db *) mentioned here is such that dL * is the difference between the L * value of the original image data and the L * value of the read image data, and da * is the a * of the original image data. Is calculated by the difference between the b * value of the original image data and the b * value of the read image data.

  When each value of the calculated color differences (dL *, da *, db *) is smaller than a predetermined allowable range (ΔL *, Δa *, Δb *), original image data (L * a * b *) And the difference in color tone between the read image data (L * a * b *) and the read image data (L * a * b *) are determined not to exceed the allowable range, and the calculated values of the color differences (dL *, da *, db *) are within the predetermined allowable range. If the value is larger than or equal to the value of (ΔL *, Δa *, Δb *), the difference in color tone between the original image data (L * a * b *) and the read image data (L * a * b *) is allowed. It is determined that the range is exceeded.

  The values of the permissible ranges (ΔL *, Δa *, Δb *) are stored in advance in the memory 205 of the CPU 20, and the comparison discriminating unit 203 is able to set the permissible ranges (ΔL *, Δa *, Δb *) when appropriate. Compare and determine by referring to the value.

  If the comparison determination unit 203 determines that the color tone difference between the original image data (L * a * b *) and the read image data (L * a * b *) does not exceed the allowable range (step S407). YES), based on the command signal of the conveyance control unit 202 of the CPU 20, the conveyance mechanism 80 discharges the printed matter 4 conveyed on the platen glass 2 on the upper part of the multifunction peripheral 100 to the discharge tray A93 (step S408), and the processing operation Exit.

  If it is determined in step S407 that the color difference between the original image data (L * a * b *) and the read image data (L * a * b *) exceeds the allowable range by the comparison determination unit 203. (NO in step S407), the conveyance control unit 202 of the CPU 20 instructs the conveyance mechanism 80 to discharge the printed matter 4 conveyed on the platen glass 2 on the upper part of the multifunction peripheral 100 to the discharge tray B94. 80 conveys the printed material 4 to the paper discharge tray B94 based on the instruction of the conveyance control unit 202, and the printed material 4 with poor image quality is stored in the paper discharge tray B94.

  Further, the correction unit 204 of the CPU 20 corrects the difference in color tone between the original image data (L * a * b *) and the read image data (L * a * b *) so as not to exceed the allowable range (step S410). .

  Specifically, the read image data having a color difference (dL *, da *, db *) having a value larger than a predetermined allowable range (ΔL *, Δa *, Δb *) calculated by the comparison / discriminating unit 203. This is performed by adding the value of the color difference (dL *, da *, db *) to the original image data (L * a * b *) corresponding to (L * a * b *).

  That is, a read image having a color difference (dL *, da *, db *) larger than the allowable range (ΔL *, Δa *, Δb *) of the original image data (L * a * b *). When the color difference dL * is larger than the allowable range ΔL * with respect to the original image data (L * a * b *) corresponding to the data (L * a * b *), the original image data (L * a * b *) ) L * value obtained by adding the color difference dL * value to the value L * (referred to as “corrected image data” for convenience of explanation), and when the color difference da * is larger than the allowable range Δa *, The color difference db * is changed to a * (referred to as “corrected image data” for convenience of explanation) obtained by adding the value of the color difference da * to the value of a * of the original image data (L * a * b *). Is larger than the allowable range Δb *, b * of the value obtained by adding the value of the color difference db * to the value of b * of the original image data (L * a * b *). Corrected image data is changed to) that the image data "(L * a * b *) to generate.

  Corrected image data (L * a) generated by correcting the correction unit 204 so as to reduce the difference in color tone between the original image data (L * a * b *) and the read image data (L * a * b *). * B *) is transferred to the color correction unit 54, where it is converted into corrected image data (YMCK) of 4 original color materials of 8 bits each, and color correction is performed.

  The color-corrected corrected image data (YMCK) is transferred to the gradation correction unit 55, and the corrected image data (YMCK) is subjected to gradation correction by the gradation correction unit 55 and then transferred to the screen processing unit 56. The screen is processed and transferred to the image forming unit 70.

  The corrected image data (YMCK) that has been screen-processed and output by the image processing unit 50 is transferred to the image forming unit 70, formed on the paper 92 conveyed from the paper feed tray 91, and output as the printed matter 4. The processing operations from step S403 to step S410 described above are repeated until the difference between the original image data and the read image data read from the printed material 4 does not exceed the allowable range.

  As described above, since the color tone of the printed matter obtained by printing the original image data is faithfully reproduced with respect to the original image data, the destination of the printed matter is distinguished and conveyed. It is possible to easily distinguish between those with good color tone and those with no color tone.

  In addition, the printed material on which the original image data is printed by the printing process is automatically conveyed to a reading device that reads the image of the printed material, and the color tone of the image data of the printed material read by the reading device and the original image data corresponding to the image data is read. It is determined whether or not the difference of the original image exceeds the allowable range, and if it exceeds the allowable range, the original image data is subjected to appropriate correction so as not to exceed the allowable range and reprinted. Even if the operation is performed a plurality of times until the color tone of the printed matter obtained by printing the data is faithfully reproduced with respect to the original image data, the operator's hand is not bothered.

1 is a block diagram illustrating a functional configuration of an MFP 100 to which an image forming apparatus and a control method thereof according to the present invention are applied, and a configuration diagram illustrating a main part of the overall configuration. Configuration diagram showing detailed configuration of MFP 100 The block diagram which shows the functional structure of CPU20 A flowchart showing the processing operation of the main part of the multifunction machine 100

Explanation of symbols

1, 4 Printed matter 2 Platen glass 3 Platen cover 10 Client PC
20 CPU (= Central Processing Unit)
21 Bus 30 External interface (external I / F)
40 Image Reading Unit 41 Light Source Lamp 42 First Reflective Mirror 43 Second Reflective Mirror 43
44 Third reflector 44
45 Figure lens 45
46 photoelectric conversion element 47 A / D converter 47
DESCRIPTION OF SYMBOLS 50 Image processing part 51 Image data generation part 52, 53 Color conversion part 54 Color correction part 55 Gradation correction part 56 Screen processing part 60 Image data storage part 70 Image formation part 71 Pulse generation part 72 Exposure control part 73Y-73K Exposure apparatus 74Y-74K charging device
75Y to 75K Developing device 76Y to 76K Photoconductor 77Y to 77K Primary transfer roll 78 Intermediate transfer body 79 Driven roll 711a Pressure roll 711b Drive roll 712 Fixing device 713 Pickup roll 714a, 714b Registration roll 80 Transport mechanism 90 User interface 91 Supply Paper tray 92 Paper 93 Output tray A
94 Output tray B
95 Network 100 MFP 201 Control Unit 202 Transport Control Unit 203 Comparison Discrimination Unit 204 Correction Unit 205 Memory

Claims (6)

In an image forming apparatus that performs printing processing based on original image data,
Original image data storage means for storing original image data for performing the printing process;
Reading means for optically reading an image of a printed matter printed by the printing process;
Comparing means for comparing the read image data read by the reading means with the original image data corresponding to the read image data stored in the original image data storage means;
If the difference between the read image data and the original image data is within a preset allowable range according to the comparison result by the comparison means, the printed matter is discharged to the first discharge port, and is outside the preset allowable range. An image forming apparatus, comprising: a discharge control unit configured to discharge the printed matter to the second discharge port. A correction unit that corrects the original image data based on the read image data when a difference between the read image data and the original image data is outside a preset allowable range based on a comparison result by the comparison unit;
The image forming apparatus according to claim 1, further comprising: a reprint control unit that performs reprinting based on the corrected image data corrected by the correction unit. In an image forming apparatus that performs printing processing based on original image data,
Original image data storage means for storing original image data for performing the printing process;
Reading means for optically reading an image of a printed matter printed by the printing process;
Comparing means for comparing the read image data read by the reading means with the original image data corresponding to the read image data stored in the original image data storage means;
When the difference between the read image data and the original image data is within a preset allowable range based on the comparison result by the comparison means, the printed matter is discharged to the first discharge port, and the predetermined allowable range is exceeded. A discharge control means for discharging the printed matter to the second discharge port,
A correction unit that corrects the original image data based on the read image data when a difference between the read image data and the original image data is outside a preset allowable range based on a comparison result by the comparison unit;
An image forming apparatus comprising: a reprint control unit that performs reprinting based on the corrected image data corrected by the correction unit. In a control method of an image forming apparatus that performs a printing process based on original image data,
The original image data for performing the printing process is accumulated by the original image data accumulating means,
An image of the printed matter printed by the printing process is optically read by a reading unit,
The comparison unit compares the read image data read by the reading unit and the original image data corresponding to the read image data stored in the original image data storage unit,
When the difference between the read image data and the original image data is within a preset allowable range by the discharge control unit based on the comparison result by the comparison unit, the printed matter is discharged to the first discharge port and set in advance. A control method for an image forming apparatus, wherein the printed matter is discharged to a second discharge port when it is out of an allowable range. When the difference between the read image data and the original image data is outside a preset allowable range according to the comparison result by the comparison means, the correction means corrects the original image data based on the read image data,
The method of controlling an image forming apparatus according to claim 4, wherein the corrected image data corrected by the correcting unit is reprinted by the reprinting control unit. In a control method of an image forming apparatus that performs a printing process based on original image data,
The original image data for performing the printing process is accumulated by the original image data accumulating means,
An image of the printed matter printed by the printing process is optically read by a reading unit,
The read image data read by the reading means and the original image data corresponding to the read image data stored in the original image data storage means are compared by the comparison means,
When the difference between the read image data and the original image data is within a preset allowable range by the discharge control unit based on the comparison result by the comparison unit, the printed matter is discharged to the first discharge port and set in advance. If it is outside the allowable range, discharge the printed matter to the second outlet,
When the difference between the read image data and the original image data is outside a preset allowable range based on the comparison result by the comparison unit, the correction unit corrects the original image data based on the read image data,
A control method for an image forming apparatus, wherein the correction image data corrected by the correction unit is reprinted by a reprint control unit.

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