JP2018137693A - Image formation device and image formation device control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device which prevents the accuracy of detecting a printed matter from being deteriorated.SOLUTION: On the basis of a result of reading a sheet with images formed thereon, the images on the sheet are inspected. Plural areas to be inspected are defined on a sheet, a first area for a first sheet is inspected, a second area different from the first area for a second sheet different from the first sheet is inspected, and the first area for a sheet on which the images are formed after the first sheet and the second sheet is inspected.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image forming apparatus for forming an image on a sheet and a control method for the image forming apparatus.

  In the commercial print market such as the photo print, photo album market, and POD (Print On Demand), the variety of print products and the types of print media, etc., increase with the various printing needs that differ from user to user. doing. In addition, with the diversification of printing needs, the printing mechanism of the image forming apparatus has become complicated. An image forming apparatus often has a function of simultaneously accepting a plurality of print data (also called a print job or simply a job) and printing them continuously. In continuous printing, there are image forming apparatuses in which a plurality of sheets are loaded on a conveyance path and printed at high speed. In double-sided printing, there is an image forming apparatus that prints the back side by inverting the paper by a switchback mechanism provided in the transport path after printing on one side.

  In commercial printing, it is important to maintain the quality of the printed matter in addition to the printing speed, but the inspection work for determining the quality of the printed matter has become complicated, and the work load has also increased. In the inspection work, the inspection is performed by imaging the printed matter printed on the print medium by the image forming apparatus. If strict inspection is performed on all printed matter, a great inspection load is generated, which affects subsequent workflows such as bookbinding. Japanese Patent Laid-Open No. 2004-133830 describes the inspection items based on the printing speed based on the priority order of the inspection items based on the characteristics of the image data that is the basis of the print image and the priority order of the inspection items based on the printing environment information such as temperature and humidity. It is described to select and inspect a printed image within a limited time.

Japanese Patent No. 4622252

  When inspecting a printed image by imaging the printed matter in inspection work, if the entire printed matter is inspected, the inspection time increases, and the inspection time becomes longer than the printing time in the image forming apparatus, reducing the throughput of the entire workflow. End up. Therefore, in the inspection of the printed image, the inspection area is divided and a specific area in the inspection area is inspected.

  In Patent Document 1, a print image is inspected from the characteristics of image data that is the basis of the print image and information about the print environment. However, the region to be inspected for each inspection becomes irregular, and when a defect is found by inspection, it is not known how far back from the printed matter in which the defect is found to reconfirm the printed matter. As a result, the processing cost when a defect is found increases, and the efficiency of inspection is reduced.

  An object of the present invention is to solve such conventional problems. In view of the above, it is an object of the present invention to provide an image forming apparatus and a control method for the image forming apparatus that prevent a decrease in the efficiency of inspection of printed matter.

  In order to solve the above problems, an image forming apparatus according to the present invention includes an image forming unit that forms an image on a sheet, a reading unit that optically reads a sheet on which an image is formed by the image forming unit, and the reading unit. Inspection means for inspecting an image on the sheet based on the reading result by the means, and a plurality of areas to be inspected by the inspection means are defined, and the inspection means is provided for the first sheet. The first area is inspected, the second area different from the first area is inspected with respect to the second sheet different from the first sheet, and the first sheet and the second sheet are The first area is inspected for a sheet to be imaged later.

  According to the present invention, it is possible to prevent a decrease in the efficiency of inspection of printed matter.

1 is a diagram illustrating an overall configuration of an image forming apparatus. 2 is a block diagram illustrating a control system of the image forming apparatus. FIG. 2 is a diagram illustrating a software system configuration of an image forming apparatus. FIG. It is a figure which shows a test | inspection area | region. It is a figure which shows a mode that each inspection area | region is allocated cyclically. It is a figure which shows test | inspection log | history data. It is a flowchart which shows the inspection process of a printed image. It is a figure which shows the example which detected the defect of the printed image during continuous printing. FIG. 6 is a diagram illustrating print job information. It is a figure which shows test | inspection log | history data. It is a figure which shows the example which detected the defect of the printed image during continuous printing. It is a figure which shows test | inspection log | history data. It is a figure which shows test | inspection log | history data. It is a figure which shows test | inspection log | history data. It is a figure which shows a test | inspection area | region. It is a figure which shows the example of the notification to a user.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the present invention. . The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

[First Embodiment]
FIG. 1 is a cross-sectional view showing an overall configuration of an image forming apparatus 100 using cut sheets (sheets that have been trimmed to a predetermined size, such as A3 and A4). The image forming apparatus 100 is not limited to a dedicated machine specialized in the printing function, and includes a multifunction machine that combines the printing function and other functions, a manufacturing apparatus that forms an image or pattern on a recording sheet, and the like. The image forming apparatus 100 includes a paper feed tray 101 for A4 size and a paper feed tray 102 for A3 size. Although FIG. 1 shows A4 size and A3 size paper feed trays, paper trays for other sizes may be configured. In addition, the image forming apparatus 100 includes a paper conveyance rotation roller 103, a recording head 104, and a scanner unit 107. The image forming apparatus 100 also includes an ink tank 105, a drying unit 106, a paper reversing unit 108, a sorting unit 109, and an operation unit unit 111.

  The sheets (sheets) fed from the sheet feed tray 101 or 102 are conveyed in the direction a and the direction i, respectively. Here, the conveyed paper is cut paper. The paper fed from the paper feed tray 101 or 102 is transported in the direction b by the transport rotating roller 103. In addition to the one shown in FIG. 1, the rotation roller 103 for conveyance is arranged on the entire conveyance path in FIG. 1, and can convey the sheet to a predetermined position at an arbitrary speed by motor control. it can. Note that the paper feed tray is not limited to two stages, and may be composed of one to a plurality of stages depending on the configuration of the image forming apparatus 100.

  The paper fed from the paper feed tray 101 or 102 passes under the recording head 104 through the transport path. In the recording head 104, independent ink-jet recording heads for a plurality of colors are configured along the paper transport direction. In the present embodiment, for example, it is assumed that independent ink jet recording heads for six colors are configured. By ejecting ink from the recording head 104 in synchronization with the conveyance of the paper, an image is formed on the paper (on the sheet). The ink tank 105 stores ink independently for each color. The ink stored in the ink tank 105 is supplied to the recording head 104 corresponding to each color via a tube. The recording head 104 is a line type recording head juxtaposed for each color along the transport direction b during printing. The line-type recording head corresponding to each color may be seamlessly formed with a single nozzle tip, or the divided nozzle tips are regularly arranged like a single row or a staggered arrangement. There may be. In the present embodiment, a so-called full multihead in which the nozzles are configured in a range that covers the print width of the maximum paper to be used. As an ink jet recording method for discharging ink from a nozzle, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS element, or the like is adopted. Based on the image data to be printed, ink is ejected from the nozzles of each recording head onto the paper to form an image. The sheet on which the image is formed is conveyed to the drying unit 106 by the conveying rotation roller 103.

  In the drying unit 106, in order to dry the paper to which ink has been applied in a short time, the paper passing through the unit is heated with warm air. The paper that has passed through the drying unit 106 is transported in the direction c to the scanner unit 107. The scanner unit 107 reads a print image or a special pattern for inspection, and based on the read result, checks whether there is a problem with the image formed on the paper and checks the state of the apparatus. In this embodiment, the scanner unit 107 is configured in the image forming apparatus 100, but may be configured as an external unit. The paper that has passed through the scanner unit 107 is transported in the direction d to the reversing unit 108. The reversing unit 108 conveys the sheet so as to reverse the front and back of the passing sheet. As a method of inverting the paper, there are a switchback method, a method of gently twisting the conveyance path, and the like. The switchback method temporarily stops the movement of the paper. On the other hand, the method of twisting the conveyance path can keep the sheet conveyance speed constant, and enables higher-speed printing. When the sheet passes through the reversing unit 108, the sheet is conveyed in the direction f. At that time, the sheet is transported again with the front and back reversed. The re-conveyed paper is further conveyed in the direction b and returned again to the conveyance path in which the recording heads are arranged.

  As shown in FIG. 1, the routes b to c to d to f to b are configured as circulating routes and are controlled so that the front surface and the back surface are switched every round. On the other hand, the paper on which image formation has been completed branches and is conveyed in the direction g without passing through the reversing unit 108, and is conveyed to the sorting unit 109. That is, the single-sided printing paper branches in the direction g in the middle of the first round, and the double-sided printing paper branches in the middle of the second round. The paper that branches in the direction g and passes through the sorting unit 109 is transported in the h direction and stacked on the paper discharge tray 110 of the number set for each print image while being confirmed by the sensor. The sorting unit 109 includes a plurality of paper discharge trays 110, and sorts paper discharge trays on which sheets are stacked according to a paper discharge method such as a job unit or a copy unit.

  The operation unit 111 is a unit that displays a print status for each job, such as in which paper discharge tray a specified job is stacked, whether printing is in progress, printing has ended, or an error has occurred. is there. The operation unit 111 displays various user interface screens in addition to the above information. For example, the operation unit 111 displays a user interface screen for performing apparatus maintenance such as confirmation of the apparatus state such as the remaining ink amount and remaining sheet amount, and head cleaning. The operation unit 111 can accept operations such as instructions and settings from the user via the user interface screen.

  FIG. 2 is a block diagram illustrating a control system of the image forming apparatus 100. The CPU 201 is in the form of a microcomputer or the like and controls the image forming apparatus 100 in an integrated manner. The ROM 202 stores, for example, a control program and fixed data, and the RAM 203 stores work data for analyzing print data received from the external host device 213 and performing print control as a print job, for example. The HDD 204 temporarily stores print data received from the host device 213. Print data transmitted from the host device 213 is received by the control program on the ROM 202 via the external interface (I / F) 205. Print job information is stored in the RAM 203, and image data associated with the print job is stored on the HDD 204.

  The operation unit 205 corresponds to the operation unit 111 of FIG. 1, and includes a display for displaying the state of the image forming apparatus 100, etc., and displays an instruction input from the operator, various data registration, and the state of the image forming apparatus 100. To do. The image processing unit 207 performs various types of image processing and converts, for example, a color space (for example, YCbCr) of image data into a standard RGB color space (for example, sRGB). Further, the image processing unit 207 executes various image processing such as resolution conversion to an effective number of pixels, image analysis, image correction, and the like as necessary. The image data that has undergone these image processes is stored in the RAM 203 or the HDD 204.

  The printer engine 208 controls to print the image data on a recording medium such as paper according to the received control command. An ink ejection instruction to the recording head corresponding to each color, an ejection timing setting for adjusting a dot position on the recording medium, acquisition of a recording head driving state, and the like are performed. The printer engine 208 controls the driving of the recording head based on the image data, and ejects ink from the recording head to form an image on the recording medium. In addition, the printer engine 208 controls the conveyance roller based on a feed roller driving instruction, a conveyance roller driving instruction, acquisition of the rotation state of the conveyance roller, and the like, and conveys or stops the recording medium at an appropriate speed. The scanner engine 209 controls image sensors such as a CCD and a CIS according to the received control command, analyzes red (R), green (G) and blue (B) analog luminance data, and reads Control to optically read an image on an object.

  The paper transport unit 210 switches whether the image-formed paper is sent to the reversing unit 108 that reverses the front and back of the paper transported by the transport roller, or the image-formed paper is sent to the paper discharge tray for each paper. . The sorting unit 211 performs control so that the paper is discharged to a paper discharge tray having a number set for each paper.

  The host device 213 is a device configured to be able to communicate with the image forming apparatus 200 and supplies print data to the image forming apparatus 100. The host device 213 may be a computer that creates and processes image data to be printed, or may have a configuration such as a reader unit for image reading. Print data, image data, other commands, status signals, and the like supplied from the host device 213 can be transmitted to and received from the image forming apparatus 100 via the external I / F 206.

  Each block in the image forming apparatus 100 is connected by a system bus 212. The control configuration of each unit is not limited to the above configuration, and may be another configuration. For example, the configuration may be such that each unit is divided into a plurality of units and each holds and controls the CPU.

  FIG. 3 is a diagram illustrating a software system configuration in the image forming apparatus 100. The job control unit 301 receives print data (hereinafter also referred to as a print job) from the host device 213, manages the status of the print job and the print order, and controls the entire print processing of the image forming apparatus 100. The print data received by the job control unit 301 is temporarily stored in the print data management area 302 of the RAM 203 or HDD 204. The job control unit 301 analyzes the print data, extracts information necessary for print processing, and stores the extracted information as job information in the job information management area 303 of the RAM 203.

  The image processing unit 304 analyzes the print data and develops it into image data suitable for printing. The image processing unit 304 extracts print data from the print data management area 302 according to an instruction from the job control unit 301, and stores image data generated based on the extracted print data in the image data management area 305 of the RAM 203 or the HDD 204.

  In response to an instruction from the job control unit 301, the printer control unit 306 transmits the image data stored in the image data management area 305 to the printer engine 208, and outputs it as a print image. The printer control unit 306 controls the paper transport unit 210 and the sorting unit 211 together with the printer engine 208, and is a sheet of image data that is fed from the designated paper feed tray and discharged from the paper discharge tray via the transport path. Controls the overall printing operation for The printer control unit 306 notifies the print image inspection unit 307 of image data to be output as a print image.

  The print image inspection unit 307 compares the read data obtained by reading the paper on which the image data is printed with the scanner unit 209 with the image data sent from the printer control unit 306, and determines whether or not printing is correctly performed. . The print image inspection unit 307 includes an image inspection unit 307a, an inspection region selection unit 307b, and an inspection history management unit 307c.

  The image inspection unit 307 a acquires image data notified from the printer control unit 306 from the image data management area 305 according to an instruction from the job control unit 301. Next, the image inspection unit 307a acquires read data from the read data management region 309 via the scanner control unit 308 based on the inspection region selected by the inspection region selection unit 307b, and determines whether the print image is good or bad. . The result of the pass / fail judgment is notified to the inspection history management unit 307c.

  The inspection region selection unit 307b acquires a past inspection history from the inspection history management unit 307c according to an instruction from the image inspection unit 307a, and notifies the image inspection unit 307a of the inspection region of the print image. The inspection history management unit 307 c stores the inspection history of the print image in the inspection history data management area 310 of the RAM 203 according to an instruction from the image inspection unit 307 a. Further, the inspection history management unit 307c acquires the inspection history stored in the inspection history data management area 310 according to instructions from the image inspection unit 307a and the inspection area selection unit 307b.

  The scanner control unit 308 controls the scanner engine 209 according to an instruction from the image inspection unit 307a, optically reads a sheet on which image data is printed, and acquires read data. The scanner control unit 308 not only reads an object to be read, but also can specify an inspection area notified from the image inspection unit 307a as a reading area by the scanner engine 209 and perform reading. The scanner control unit 308 stores the acquired read data in the read data management area 309 of the RAM 203 or HDD 204.

  The operation unit 311 displays a print image inspection result, a print job status, and the like to the user, and controls a display device such as a touch panel, a pointing device, and an input / output device such as a keyboard via the operation unit 205. The operation unit 311 controls to acquire the inspection result and job information from the print image inspection unit 307 and the job control unit 301, respectively, and display them on the display device. Further, the operation unit 311 accepts an operation for a print job such as cancellation of a displayed print job or interruption of printing via the operation unit 205.

  An example of an inspection area to be inspected for a print image will be described with reference to FIG. A sheet 401 indicates a recording medium on which image data is printed. An area 402 is an area in which the entire area of the sheet 401 is divided in the sub-scanning direction and the divided areas are combined into one. In the present embodiment, as shown in FIG. 4, the sheet inspection area 402 is divided into three. When the sheet 401 is an A4 size sheet having a sub-scanning length of 297 mm, the first inspection area 402a is an area from 0 mm to 100 mm. The second inspection area 402b is an area from 100 mm to 200 mm. The third inspection area 403c is an area from 200 mm to 297 mm. In the present embodiment, the inspection area 402 will be described with a fixed value of 3 as the number of divisions. However, the number of divisions is received via the operation unit 311 and is dynamically stored in the inspection area selection unit 307b via the image inspection unit 307a. You may comprise so that it may do.

  Further, the width of the inspection area may be determined according to the type of paper and the inspection accuracy. The inspection cost varies depending on the configuration of the print image. In the present embodiment, the width of the inspection area is constant. However, the width of the inspection area may be changed in a range in time for the printing speed without making the width of the inspection area constant.

  FIG. 5 is a diagram illustrating a state in which each divided inspection area is cyclically (cyclically) assigned to each sheet. Sheets 501, 502, 503, and 504 respectively indicate recording media on which image data is printed. The sheet 501 is output from the image forming apparatus 100 in order from the sheet 501 to the sheet 504. As shown in FIG. 5, if the inspection area of the paper 501 is the inspection area 402a shown in FIG. 4, the inspection area 402b following the inspection area 402a is assigned to the inspection area of the subsequent paper 502. Further, an inspection area 402c subsequent to the previous inspection area 402b is assigned as an inspection area of the subsequent sheet 503. As the inspection area of the paper 504, the inspection area 402a is assigned because the inspection area is completely assigned to the paper in the previous inspection area 402c. For the inspection area allocation, the inspection area selection unit 307b acquires inspection history data from the inspection history management unit 307c, and cyclically determines each inspection area based on the previous inspection area.

  FIG. 6 is a diagram illustrating an example of examination history data stored in the examination history data management area 310. The inspection history data includes an inspection history number 601, an inspection area start line 602, an inspection area end line 603, a page number 604, and a job number 605. The inspection history number 601 represents the inspection execution order. The inspection area start line 602 represents the inspection area start line, and the inspection area end line 603 represents the inspection area end line. The page number 604 is associated with the image data to be inspected, and the job number 605 is associated with the print job corresponding to the image data.

  The inspection items 606a and 606b are added and updated every time inspection is performed. As shown in FIG. 5, when the recording medium is an A4 size paper, when the inspection of the print image on the paper 502 is completed, the inspection history of the print image on the paper 502 is set as the latest inspection item 606a, and the previous paper. The inspection history of the print image 501 is recorded as the inspection item 606b. The page number 604 and the job number 605 are stored based on information notified from the job control unit 301 and the printer control unit 306.

  FIG. 7 is a flowchart showing a print image inspection process in the present embodiment. Each process in FIG. 7 is realized, for example, by the CPU 201 reading out a program stored in the ROM 202 to the RAM 203 and executing it. In FIG. 7, the image inspection unit 307a acquires the inspection area of the image data notified from the printer control unit 306 via the inspection area selection unit 307b according to the instruction of the job control unit 301.

  First, in S701, the examination area selection unit 307b acquires examination history data from the examination history management unit 307c, and determines whether or not past examination items are stored in the examination history data management area 310. If it is determined that the past inspection items are stored, the process proceeds to S702, and the inspection region selection unit 307b acquires the inspection region end line 603 corresponding to the inspection item of the latest inspection history number 601 from the inspection history data. To do. Then, the inspection area selection unit 307b determines an inspection area following the acquired inspection area end line 603, and performs the inspection items as the inspection area start line and the inspection area end line, respectively, as the start line and the end line of the determined area. Is generated and notified to the image inspection unit 307a. On the other hand, if it is determined in S701 that the past inspection items are not stored, the process proceeds to S703, and the inspection area selection unit 307b performs the inspection area from the front end of the sheet as the inspection area start line and the inspection area end line. An inspection item is created and notified to the image inspection unit 307a.

  In step S <b> 704, the image inspection unit 307 a acquires image data corresponding to the print image from the image data management area 305. Next, the image inspection unit 307a acquires the inspection region start line and the inspection region end line of the print image from the inspection region selection unit 307b, and the scanner control unit 308 acquires the read image of the inspection region. When the acquisition of the read image in the inspection area is completed and the read data is stored in the read image management data management area 309, the image inspection unit 307a compares the acquired image data with the read data and determines whether the print image is good or bad. Perform an inspection.

  In step S <b> 705, the image inspection unit 307 a determines the presence / absence of a defect in the print image in the inspection region as a result of the quality check of the print image. If it is determined that there is a defect in the print image, the process advances to step S706, and the image inspection unit 307a notifies the job control unit 301 and the operation unit 311 that a defect in the print image has been detected. In step S707, the image inspection unit 307a acquires inspection history data from the inspection history management unit 307c. The image inspection unit 307a determines a print image corresponding to the inspection item remaining as the inspection history as a defect reconfirmation image that may cause a defect in detection of a defect in the print image, and sends it to the job control unit 301 and the operation unit 311. Notice. In S708, the inspection items remaining in the inspection history are deleted, and the processing in FIG.

  On the other hand, if it is determined in S705 that there is no defect in the print image in the print image inspection, the process proceeds to S709. In step S709, the image inspection unit 307a acquires inspection history data from the inspection history management unit 307c. The image inspection unit 307a determines whether or not the entire area of the sheet has been inspected in a circulating manner from the inspection area of the execution inspection item and the inspection area of each inspection item of the acquired inspection history data. Here, the oldest inspection item in the inspection history data is set as the oldest inspection item. If the inspection area start line of the oldest inspection item is 0, the entire area of the paper is circulated if the inspection area of the inspection item of the inspection item and the inspection history data includes the lowermost area of the paper. It is determined that it was inspected. In addition, if the inspection area start line of the oldest inspection item does not become 0, if the inspection area end line of the execution inspection item matches or exceeds the inspection area start line of the oldest inspection item, the area of the entire sheet Is determined to have been inspected in a circulating manner.

  When it is determined by the image inspection unit 307a that the inspection area has been inspected once, the image inspection unit 307a deletes the oldest inspection item of the acquired inspection history data in S710. In step S711, the image inspection unit 307a notifies the inspection history management unit 307c of the inspection item as the latest inspection item of the inspection history data, and ends the inspection. The inspection history management unit 307c updates the inspection history data stored in the inspection history data management area with the content received from the image inspection unit 307a. After the processing of S711, the processing of FIG. 7 is repeated for subsequent image data.

  On the other hand, if it is determined in S709 that the inspection area has not been completed or there is no inspection history data, the process proceeds to S712, and the image inspection unit 307a determines that the print image to be inspected by the execution inspection item is the last print image of the print job. It is determined whether or not. If it is determined that there is unexamined image data notified from the job control unit 301 and the printer control unit 306, the process advances to step S711. In step S711, the image inspection unit 307a notifies the inspection history management unit 307c of the execution inspection item as the latest inspection item of the inspection history data, and repeats the processing in FIG. 7 for the subsequent image data. On the other hand, if it is determined in S712 that there is no unexamined image data, the process proceeds to S708, where the inspection items remaining in the inspection history are deleted, and the inspection ends. In the present embodiment, the inspection history data is cleared for each job, but a plurality of jobs may be held continuously. Alternatively, the inspection history may be held until a fixed time or a fixed time input from the operation unit 311 elapses, and the inspection history may be deleted after the fixed time or the fixed time elapses.

  FIG. 8 is a diagram showing a change in inspection history data when a defect in a print image is detected during continuous printing in accordance with the processing in FIG. Sheets 801a, 802a, 803a, and 804a in FIG. 8 respectively indicate sheets on which image data of a print job including four pages P1 to P4 is printed. The order of output from the image forming apparatus 100 is output from the sheet 801a to the sheet 804a. FIG. 8 shows an example in which a defect in the print image is detected during the inspection of the print image on the paper 804a. In addition, inspection areas 801b, 802b, 803b, and 804b indicate inspection areas for inspecting printed images on the sheets 801a, 802a, 803a, and 804a, respectively. In the example of FIG. 8, the paper sub-scanning length is 297 mm, and the paper inspection area is divided into an inspection area of 0 mm to 100 mm, an inspection area of 100 mm to 200 mm, and an inspection area of 200 mm to 297 mm.

  The inspection history data 801c is inspection history data after the inspection of the paper 801a, the inspection history data 802c is inspection history data after the inspection of the paper 802a, and the inspection history data 803c is an inspection history after the inspection of the paper 803a. It is data. Each inspection history data 801c to 803c stores each inspection item of the inspection history data.

  First, in the inspection of the sheet 801a, since there are no inspection items in the inspection history data, the process proceeds to S703 based on the determination in S701. In step S703, the inspection area selection unit 307b selects the inspection area 801b from the front end of the sheet, thereby determining the inspection item for the sheet 801a. In S704 and S705, when the inspection of the printed image based on the inspection item by the image inspection unit 307a is completed, the inspection area of the sheet 801a has no defect, and the process proceeds to S709 according to the determination in S705. After the printed image on the sheet 801a is inspected, it is determined that the inspection area is not completed from the inspection item and the inspection item remaining in the inspection history data, and the process proceeds to S712 due to the determination in S709. In S712, since the sheet 801a does not correspond to the last image data of the print job, the process proceeds to S711 according to the determination in S712, and the contents of the execution inspection item of the sheet 801a are registered as the inspection history data 801c.

  Subsequently, in the inspection of the sheet 802a, since the inspection item of the sheet 801a is registered in the inspection history data, the process proceeds to S702 based on the determination in S701. In step S702, the inspection area selection unit 307b selects an inspection area 802b that follows the inspection item on the sheet 801a that is closest to the inspection history data, and determines the inspection area 802b as an inspection item for the print medium 802a. In S704 and S705, when the inspection of the print image based on the inspection item by the image inspection unit 307a is completed, there is no defect in the inspection area of the sheet 802a, and the process proceeds to S709 according to the determination in S705. After the printed image on the sheet 802a is inspected, it is determined that the inspection area has not been completed from the inspection item to be tested and the inspection item remaining in the inspection history data, and the process proceeds to S712 due to the determination in S709. In S712, since the sheet 802a does not correspond to the last image data of the print job, the process proceeds to S711 based on the determination in S712, and the content of the inspection item on the sheet 802a is the latest in the inspection history data as in the inspection history data 802c. Registered as an inspection item.

  Subsequently, in the inspection of the sheet 803a, since the inspection items of the sheets 801a and 802a are registered in the inspection history data, the process proceeds to S702 based on the determination in S701. In step S702, the inspection area selection unit 307b selects an inspection area 803b that follows the inspection item on the sheet 802a that is closest to the inspection history data, and determines the inspection area 803b as an inspection item for the print medium 803a. In S704 and S705, when the inspection of the printed image based on the inspection item by the image inspection unit 307a is completed, there is no defect in the inspection area of the sheet 803a, and the process proceeds to S709 according to the determination in S705. After the printed image on the paper 803a is inspected, it is determined that the inspection area is completed from the inspection item and the inspection item remaining in the inspection history data, and the process proceeds to S710 by the determination in S709. In S710, the inspection item on the sheet 801a, which is the oldest inspection item, is deleted from the inspection history data 802c. Next, in S711, the contents of the inspection item on the sheet 803a are registered as the latest inspection item of the inspection history data, and the inspection history data is updated as shown in the inspection history data 803c.

  Subsequently, in the inspection of the sheet 804a, since the inspection items of the print media 803a and 802a are registered in the inspection history data, the process proceeds to S702 based on the determination in S701. In step S702, the inspection area selection unit 307b selects an inspection area 804b that follows the inspection item on the paper 803a that is closest to the inspection history data, and determines the inspection area 804b as an inspection item on the paper 804a. In S704 and S705, if a defect of the print image is detected in the print image inspection based on the inspection item by the image inspection unit 307a, the process proceeds to S706 by the determination in S705. In step S <b> 706, the fact that a print image defect has been detected on the sheet 804 a is notified to the job control unit 301 and the operation unit 311 together with the job number 605 and page number 604 of the execution inspection items. Next, in S707, from the acquired inspection history data 803c, the sheets 803a and 802a remaining as inspection items are determined as defect reconfirmation images with a possibility of missing image defects. Then, the job number 605 and the page number 604 of the inspection item are notified to the job control unit 301 and the operation unit 311, respectively.

  As described above, as shown in FIG. 8, when a defect in the print image is detected in the inspection area 804b of the sheet 804a, the defect in the same print image may occur in the sheet 802a and the sheet 803a. Judge that there is sex. Then, the sheets 802a and 803a are specified as reconfirmation images.

  That is, even if the influence of dirt on the roller or the belt occurs in the area above the inspection area 802b in the drawing when the sheet 802a is inspected, the area is outside the inspection area and is not detected when the sheet 802a is inspected. In addition, since the above-mentioned area is also outside the inspection area for the paper 803a, it is not detected when the paper 803a is inspected. However, the inspection area 804b of the sheet 804a is detected because the above-described area is an inspection area.

  Therefore, in the present embodiment, the first area is inspected for the sheet 802a (first sheet), and the second area different from the first area is determined for the sheet 801a or the sheet 803a (second sheet). Inspect the area. Then, the first area is inspected with respect to the sheet 804a on which image formation is performed after the first sheet and the second sheet.

  With such a configuration, in the present embodiment, in the above case, it can be determined that there is a possibility that a defect in the same print image has also occurred in the paper 802a and the paper 803a. As a result, it is possible to reduce the cost of work for detecting defects in the printed image due to dirt, dust, and scratches on the rollers and belts, and to realize a more efficient printing workflow.

[Second Embodiment]
FIG. 9 is a diagram illustrating an example of print job information recorded in the job information management area 303 as print job information including print settings when the job control unit 301 analyzes print data. FIG. 6 shows an example of a print job in which 6-sided duplex printing is set. In the following, a print image inspection process when a print job as shown in FIG. 9 is executed will be described with respect to differences from the first embodiment.

  A job number 901 is an item for identifying a job. A page number 902 is an item for identifying a page included in the print job, and identifies image data. The job number 901 and the page number 902 are items corresponding to the job number 605 and the page number 604 included in the inspection history data shown in FIG. The paper size type 903 is an item indicating the size of the paper on which the image data is printed, and the paper type type 904 is an item indicating the type of paper on which the image data is printed. A paper feed tray type 905 is an item for designating a paper feed tray as a paper feed destination. When feeding A4 size paper, the A4 size paper feed tray 101 of FIG. 1 is designated, and when feeding A3 size paper, the A3 size paper feed tray 102 is designated. The

  The paper discharge tray type 906 is an item for designating a tray from which paper is discharged, and any one of the plurality of paper discharge trays 110 in FIG. 1 is designated. In double-sided printing, paper is fed from the paper feed tray 101 or the paper feed tray 102 in FIG. 1 for printing the first side of the paper, and the paper is transported in the transport direction e in FIG. It is sent to the reversing unit 108. Therefore, for the first side of this paper, either the paper feed tray 101 or the paper feed tray 102 is designated as the paper feed tray type 905, and the reversing unit 108 is designated as the paper discharge tray type 906. . On the other hand, in printing on the second side of the paper, this paper is fed from the reversing unit 108 with its front and back reversed, transported in the transport direction g in FIG. Therefore, for the second side of the paper, the reversing unit 108 is designated as the paper feed tray type 905, and any one of the paper discharge trays 110 is designated as the paper discharge tray type 906. Items 906a to 906f in FIG. 9 are items corresponding to image data when performing double-sided printing in which the paper size is A4 size and the paper type is plain paper.

  FIG. 10 is a diagram showing an example of inspection history data stored in the inspection history data management area 310 in the present embodiment. The inspection history data includes an inspection history number 1001, an inspection area start line 1002, an inspection area end line 1003, a page number 1004, and a job number 1005. The inspection history number 1001 represents the inspection execution order. The inspection area start line 1002 represents the start line of the inspection area, and the inspection area end line 1003 represents the end line of the inspection area. The page number 1004 is associated with image data to be inspected, and the job number 1005 is associated with a print job including image data. A paper feed tray type 1006 is an item indicating a paper feed tray specified for a print image.

  As illustrated in FIG. 10, the inspection history data is managed by the inspection history management unit 307 c for each paper feed tray type and stored in the inspection history data management area 310. An item 1007 indicates inspection history data when the paper feed tray 101 is used as a paper feed tray. Like the items 606a and 606b in FIG. 6, an inspection item is added and updated each time inspection is performed. On the other hand, an item 1008 indicates inspection history data when the reversing unit 108 is used as a paper feed tray. Like the items 606a and 606b in FIG. 6, an inspection item is added and updated each time inspection is performed.

  FIG. 11 is a diagram illustrating a change in the inspection history data when a defect in the print image is detected on the second surface of the sheet on which the image data of the print job item 906f in FIG. 9 is printed. In FIG. 11, sheets 1101a, 1102a, 1103a, 1104a, 1105a, and 1106a respectively indicate sheets on which image data of a print job is printed. According to the print job information in FIG. 9, the sheets 1101 a, 1103 a, and 1105 a are fed from the sheet feed tray 101. Then, the image data of the items 906a, 906c, and 906e is printed on the first surface of each sheet, and after the inspection of the printed image is completed, the reversing unit 108 is conveyed as a discharge tray. The sheets 1102a, 1104a, and 1106a are fed from the reversing unit 108, and the image data of the items 906b, 906d, and 906f are printed on the second surface of each sheet. Be transported.

  Also, inspection areas 1101b, 1102b, 1103b, 1104b, 1105b, and 1106b indicate inspection areas for inspecting print images on the sheets 1101a, 1102a, 1103a, 1104a, 1105a, and 1106a, respectively. As in FIG. 8, the sub-scanning length of the paper is 297 mm, and the paper inspection area is divided into an inspection area of 0 mm to 100 mm, an inspection area of 100 mm to 200 mm, and an inspection area of 200 mm to 297 mm. The inspection history data 1101c, 1102c, 1103c, 1104c, and 1105c indicate inspection history data after inspection of the print images on the sheets 1101a, 1102a, 1103a, 1104a, and 1105a, respectively.

  In the present embodiment, the inspection area selection unit 307b specifies the paper feed tray type 1006, acquires the inspection history data from the inspection history management unit 307c, and thereafter, the processing of FIG. 7 is executed based on the acquired inspection history data. Is done.

  First, in the inspection of the paper 1101a, the inspection history data of the paper feed tray 101 is acquired. Since there is no inspection item in the inspection history data of the paper feed tray 101, the inspection area 1101b from the front end of the paper is selected and determined as the execution inspection item. When the inspection of the print image is completed, the contents of the actual inspection item on the sheet 1101a are registered as the inspection item as the inspection history data 1101c of the paper feed tray 101.

  Subsequently, in the inspection of the sheet 1102a, the inspection history data of the reversing unit 108 is acquired. Since there is no inspection item in the inspection history data of the reversing unit 108, the inspection area 1102b from the front end of the sheet is selected and determined as the inspection item to be executed. When the inspection of the print image is completed, the contents of the inspection item on the sheet 1102a are registered as the inspection item as the inspection history data 1102c of the reversing unit 108.

  Subsequently, in the inspection of the paper 1103a, the inspection history data of the paper feed tray 101 is acquired. Since the inspection items of the print medium 1101a are registered in the inspection history data, the inspection region selection unit 307b selects the inspection region 1103b that follows the inspection item of the paper 1101a that is closest to the inspection history data, and performs the inspection of the paper 1103a. Determine as an item. When the inspection of the print image is completed, the contents of the actual inspection item of the sheet 1103a are registered as the latest inspection item of the inspection history data of the paper feed tray 101 like the inspection history data 1103c of the paper feed tray 101.

  Subsequently, in the inspection of the sheet 1104a, the inspection history data of the reversing unit 108 is acquired. Since the inspection item of the sheet 1102a is registered in the inspection history data, the inspection area selection unit 307b selects the inspection area 1104b that follows the inspection item of the sheet 1102a that is closest to the inspection history data, and performs the inspection of the print medium 1104a. Determine as an item. When the inspection of the printed image is completed, the contents of the actual inspection item on the sheet 1104a are registered as the latest inspection item of the inspection history data of the reversing unit like the inspection history data 1104c of the reversing unit 108.

  Subsequently, in the inspection of the paper 1105a, the inspection history data of the paper feed tray 101 is acquired. The inspection area selection unit 307b selects the inspection area 1105b that follows the inspection item of the sheet 1103a that is closest to the inspection history data, and determines the inspection area 1105b as the inspection item of the sheet 1104a. After the inspection is completed, the inspection area for the sheet is completed in the inspection area designated by the inspection item of the sheet 1105a. Accordingly, the inspection item of the paper 1101a, which is the oldest inspection item, is deleted from the inspection history data of the paper feed tray 101. Then, the contents of the inspection inspection item of the sheet 1105a are registered as the latest inspection item of the inspection history data of the paper feed tray 101 like the inspection history data 1105c.

  Subsequently, in the inspection of the sheet 1106a, the inspection history data of the reversing unit 108 is acquired. The inspection area selection unit 307b selects the inspection area 1106b that follows the inspection item of the paper 1104a that is closest to the inspection history data, and determines the inspection area 1106b as the inspection item of the paper 1104a. When a defect in the print image is detected after the inspection is completed, the fact that the defect in the print image has been detected in the sheet 1106a is notified to the job control unit 301 and the operation unit 311 together with the job number 1105 and the page number 1104 of the inspection item to be checked. Notice. Next, the sheets 1102a and 1104a remaining in the history as inspection items from the acquired inspection history data of the reversing unit 108 are determined as defect reconfirmation images with the possibility of missing image defects. The job control unit 301 and the operation unit 311 are notified of the job number 1105 and the page number 1104 of the inspection item, respectively.

  As described above, when a defect is detected in the paper 1106a printed using the reversing unit 108 as the paper feed tray, the same defect is present in the printed images of the papers 1102a and 1104a using the reversing unit 108 as the paper feed tray. Judge that it may have occurred. In the present embodiment, the inspection history data is managed for each paper feed tray that feeds paper, and based on the respective inspection history data, inspection areas are cyclically designated and inspected. Then, the range of the preceding paper in which the same defect may occur is specified. As a result, the work cost for detecting defects in the printed image is suppressed, and a more efficient printing workflow can be realized. In addition, since the entire area of the paper is inspected a plurality of times, it is possible to suppress detection failure of a defect in a printed image due to dirt, dust, or scratches on a roller or a belt as compared with the conventional technique.

[Third Embodiment]
Hereinafter, the inspection history data in this embodiment will be described with respect to differences from the first and second embodiments.

  FIG. 12 is a diagram showing an example of inspection history data including the paper size type shown in FIG. 9 in the inspection history data of FIG. The inspection history data includes an inspection history number 1201, an inspection area start line 1202, an inspection area end line 1203, a page number 1204, and a job number 1205. The inspection history number 1201 represents the inspection execution order. The inspection area start line 1202 represents the start line of the inspection area, and the inspection area end line 1203 represents the end line of the inspection area. The page number 1204 is associated with the image data to be inspected, and the job number 1205 is associated with the print job including the image data. A paper feed tray type 1206 is an item indicating a paper feed tray designated for a print image. The paper size 1207 is an item indicating the size of the paper on which image data is printed, designated by the paper size type 903. The inspection history data is managed for each paper feed tray type as shown in FIG. 12, and is further managed by the inspection history management unit 307c for each paper size type for one paper feed tray type. 310. Inspection items 1208, 1209, 1210, and 1211 are inspection history data items arbitrarily determined from the paper feed tray type and the paper size type, and items are added and updated each time inspection is performed.

  The inspection area selection unit 307b designates the paper feed tray type 1206 and the paper size type 1207, acquires the inspection history data from the inspection history management unit 307c, and thereafter performs the processing shown in FIG. 7 based on the acquired inspection history data. Executed. Inspection history data is managed for each paper feed tray for feeding paper and for each paper size, and inspection is specified by cyclically specifying inspection areas based on individual inspection history data. As a result, it is possible to suppress the detection omission of defects in the printed image due to dirt, dust, or scratches on the rollers and belts in the conveyance path, which is caused by the paper size. Further, the range of the preceding paper that may have the same defect is specified. As a result, the work cost for detecting defects in the printed image is suppressed, and a more efficient printing workflow can be realized.

[Fourth Embodiment]
Hereinafter, the inspection history data in this embodiment will be described with respect to differences from the first to third embodiments.

  FIG. 13 is a diagram showing an example of inspection history data in which the paper type classification shown in FIG. 9 is included in the inspection history data of FIG. The inspection history data includes an inspection history number 1301, an inspection area start line 1302, an inspection area end line 1303, a page number 1304, and a job number 1305. The inspection history number 1301 represents the inspection execution order. The inspection area start line 1302 represents the start line of the inspection area, and the inspection area end line 1303 represents the end line of the inspection area. The page number 1304 is associated with the image data to be inspected, and the job number 1305 is associated with the print job including the image data. A paper feed tray type 1306 is an item indicating a paper feed tray designated for a print image. The paper size 1307 is an item indicating the size of the paper on which image data is printed, designated by the paper size type 903. The paper type type 1308 is an item indicating the type of paper on which image data is printed, designated by the paper type type 904. The inspection history data is managed for each paper feed tray type as shown in FIG. 13, and is further managed by the inspection history management unit 307c for each paper size type and paper type type for one paper feed tray type. Stored in the history data management area 310. The inspection items 1309, 1310, 1311, and 1312 are inspection history data inspection items arbitrarily determined from the paper feed tray type, paper size type, and paper type type. Items are added and updated each time inspection is performed. Is done.

  The inspection area selection unit 307b designates a paper feed tray type 1306, a paper size type 1307, and a paper type type 1308, acquires inspection history data from the inspection history management unit 307c, and thereafter, based on the acquired inspection history data, FIG. 7 is executed. The inspection history data is managed for each paper feed tray for feeding paper, paper size, and paper type. Based on the individual inspection history data, the inspection area is cyclically designated and inspected. As a result, it is possible to suppress detection failure of a defect in a printed image due to dirt, dust, or scratches on rollers and belts in the conveyance path. Further, the range of the preceding paper that may have the same defect is specified. For this reason, the operation cost for defect detection of a printed image is suppressed, and a more efficient printing workflow can be realized.

[Fifth Embodiment]
Hereinafter, the inspection history data in the present embodiment will be described with respect to differences from the first to fourth embodiments.

  FIG. 14 is a diagram showing an example of inspection history data stored in the inspection history data management area 310 in the present embodiment. In the present embodiment, the inspection history data includes an inspection history number 1401, an inspection area start line 1402, an inspection area end line 1403, a page number 1404, a job number 1405, and an inspection area 1409. The inspection history number 1401 represents the order of inspection execution. The inspection area start line 1402 represents the start line of the inspection area, and the inspection area end line 1403 represents the end line of the inspection area. The page number 1404 is associated with the image data to be inspected, and the job number 1405 is associated with the print job including the image data. The inspection area 1409 represents an area in the horizontal axis direction of the inspection. Here, the horizontal axis direction is a main scanning direction orthogonal to the sub-scanning direction of the paper.

  A paper size 1406 indicates a paper size. In the present embodiment, two types of paper sizes A3 and A4 will be described as examples of different sizes. As shown in FIG. 14, the inspection history data is managed by the inspection history management unit 307 c for each sheet size and stored in the inspection history data management area 310. The inspection item 1407 is inspection history data for A4 size, and the inspection item is added and updated every time inspection is performed. The inspection item 1408 is inspection history data for the A3 size, and the inspection item is added or updated every time inspection is performed.

  In the present embodiment, the inspection area 1409 is added to the inspection history data. As shown in FIG. 14, the value “FULL” is stored in the inspection area for the A4 size. Here, the value “FULL” indicates that all areas between the inspection area start line 1402 and the inspection area end line 1403 are to be inspected. On the other hand, values of “0 to 62, 358 to 420” are stored in the inspection area for the A3 size. Here, the values “0 to 62, 358 to 420” indicate the inspection region in the main scanning direction with respect to the inspection region start line 1402 and the inspection region end line 1403 representing the inspection region in the sub-scanning direction. An image of the A3 size inspection area is shown in FIG.

  Each of the sheets 1501, 1502, and 1503 in FIG. 15 represents a sheet corresponding to each A3 size page. Inspection areas 1501a and 1501c represent inspection areas from 0 mm of the inspection area start line 1402 to 250 mm of the inspection area end line 1403 and from 0 mm to 62 mm and 358 mm to 420 mm in the main scanning direction of the inspection area 1409. . The inspection area 1501b represents an inspection area from 250 mm of the inspection area start line 1402 to 420 mm of the inspection area end line 1403 and from 0 mm to 62 mm and 358 mm to 420 mm in the main scanning direction of the inspection area 1409. .

  In this embodiment, when the paper size 1406 is A3 size, the inspection area 1409 in the main scanning direction is not inspected from 0 mm to 420 mm, but the left end part from 0 mm to 62 mm and the right end part from 358 mm to 420 mm. Only the inspection area. Thereby, the distance from the inspection area start line 1402 to the inspection area end line 1403 per unit time can be increased. An area not subject to A3 size inspection, that is, an area from 62 mm to 358 mm is the same as the inspection area 1409 when the paper size 1406 is A4 size. As described above, in the present embodiment, inspection history data is managed so as to complement each other between sheets of different sizes, that is, a portion where inspection is common and a portion depending on individual paper sizes. As a result, the inspection efficiency is improved, and even when a defect is detected, it is possible to predict a defect that depends on the inspection area, and to that effect can be presented to the user.

  FIG. 16 is a diagram illustrating an example of notification to a user through a graphical user interface. For example, it is assumed that a defect is detected at “5” of the inspection history number 1401. Here, in the inspections “2” to “4” of the inspection history number 1401 for the A4 size of the paper size 1406, no defect is detected. From this, it can be said that the defect may be a defect depending on the width of the A3 size, and in the present embodiment, the fact is presented to the user like a message 1601. By presenting the maintenance information of the components of the image forming apparatus 100 as in the message 1601, the user can easily recognize the maintenance location.

  Further, as shown in a message 1603, it may be suggested that confirmation by re-examination is recommended for all “1” to “4” of the examination history number 1401. By applying such display of the message 1603 to the first to fourth embodiments, it is possible to present detection of image defects to the user in the first to fourth embodiments.

  In addition, as shown in the message 1602, it may be indicated that “1” of the inspection history number 1401 is highly necessary to be confirmed by the inspection again. As a result, image defect detection can be presented to the user more efficiently.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  100 Image forming apparatus: 104 Recording head: 107 Scanner unit: 201 CPU: 202 ROM: 203 RAM

Claims (13)

Image forming means for forming an image on a sheet;
Reading means for optically reading a sheet on which an image is formed by the image forming means;
Inspection means for inspecting an image on the sheet based on a reading result by the reading means,
A plurality of areas to be inspected by the inspecting means are defined, and the inspecting means inspects the first area with respect to the first sheet, and for a second sheet different from the first sheet Inspecting a second area different from the first area, inspecting the first area for the first sheet and a sheet imaged after the second sheet;
An image forming apparatus.   The inspection means, as an inspection of the image on the sheet, compares the image data for forming an image on the sheet with the data read by the reading means to determine the presence or absence of an image defect. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, further comprising a determining unit that determines a preceding sheet as a target to be inspected again by the inspecting unit based on an area determined to have a defect in the image. .   4. The image forming apparatus according to claim 3, wherein the determination unit determines, as the second inspection target, a sheet in which an area other than an area determined to have a defect in the image is an inspection target. 5.   5. The image according to claim 4, wherein the determination unit determines, as the second inspection target, a sheet subsequent to a sheet in which an area determined to have a defect in the image is a previous inspection target. Forming equipment.   The image forming apparatus according to claim 3, wherein the determining unit determines the sheet to be inspected again for each of the first surface and the second surface of the sheet. .   The image forming apparatus according to claim 3, wherein the determining unit determines the sheet to be inspected again for each sheet size.   The image forming apparatus according to claim 3, wherein the determination unit determines the sheet to be inspected again for each type of sheet.   9. The image forming apparatus according to claim 1, wherein the plurality of regions are determined so as to complement the regions on the sheet among a plurality of sheets having different sizes. 10. .   The image forming apparatus according to claim 1, further comprising a notification unit that notifies a message based on a result of the inspection performed by the inspection unit.   The image forming apparatus according to claim 10, wherein the message includes information on a sheet that needs to be inspected again.   The image forming apparatus according to claim 10, wherein the message includes maintenance information of the image forming apparatus. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a reading unit that optically reads a sheet on which an image is formed by the image forming unit.
An inspection step of inspecting an image on the sheet based on a reading result by the reading unit;
A plurality of regions to be inspected in the inspection step are defined, and in the inspection step, the first region is inspected with respect to the first sheet, and the second sheet different from the first sheet is inspected. Inspecting a second area different from the first area, inspecting the first area for the first sheet and a sheet imaged after the second sheet;
A control method for an image forming apparatus.

Images