Image forming apparatus, its control method and program

Abstract

The objective is to provide an image forming apparatus that can perform processing according to the area where an inspection error occurred, thereby suppressing the consumption of consumables such as printing paper due to unnecessary reprinting or purging. [Solution] The image forming apparatus comprises: an image reading unit that reads an image of a printed material and acquires a read image; an inspection determination unit that compares the read image read by the image reading unit with a correct image and makes an inspection determination; a first post-inspection processing unit that performs a first post-inspection processing for inspection errors in a first region of the read image; and a second post-inspection processing unit that performs a second post-inspection processing different from the first post-inspection processing for inspection errors in a second region of the read image.

Description

Technical Field

[0004] , ,

[0001] The present invention relates to an image forming apparatus, a control method thereof, and a program.

Background Art

[0002] "Variable printing", which performs printing while changing the information to be printed based on data, is a printing technology that can print with different contents for each sheet, such as the name and serial number of a postal item or a gift certificate. Variable printing has a "variable area", which is an area where individual data is printed, and a "fixed area", which is a common area that does not change even when the individual data is changed. That is, variable printing has a plurality of areas with different data generation methods in one printed matter. Also, in addition to variable printing, there are cases where one printed matter has a plurality of areas with different specifications, such as a "characteristic area" that requires high color reproducibility like corporate color and a "non-characteristic area" with normal color reproducibility. Thus, when inspecting a printed matter having a plurality of areas with different data generation methods or specifications, inspection can be performed for each area. For example, Patent Document 1 describes an inspection apparatus that changes the inspection criteria depending on the area.

Prior Art Documents

Patent Documents

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If an inspection error (failure to pass inspection) occurs during the inspection process, reprinting is necessary. However, the same inspection error may occur again even after reprinting. For example, if data replacement is required for a variable area in variable printing, or if ink adjustments are needed for printed materials with spot color areas, it is necessary to eliminate the cause of the inspection error before reprinting. Repeated reprinting would waste equipment operation and consumables such as printing paper. The present invention was made to solve the above problems, and aims to provide an image forming apparatus, a control method therefor, and a program that can perform processing according to the area where an inspection error occurred by performing different post-inspection processing depending on the area where the inspection error occurred, thereby suppressing the consumption of consumables such as printing paper due to unnecessary reprinting or purging. [Means for solving the problem]

[0005] To solve these problems, the imaging apparatus, control method and program according to the present invention have the following configurations (1) to (15). (1) An image forming apparatus comprising: an image reading unit that reads an image of a printed material and acquires a read image; an inspection determination unit that compares the read image read by the image reading unit with a correct image and makes an inspection determination; a first post-inspection processing unit that performs a first post-inspection processing on inspection errors in a first region of the read image; and a second post-inspection processing unit that performs a second post-inspection processing different from the first post-inspection processing on inspection errors in a second region of the read image.

[0006] (2) The image forming apparatus according to (1), wherein the inspection and judgment unit makes judgments on the first region and the second region using different judgment conditions. (3) The image forming apparatus according to (1), comprising a storage unit for storing the correct answer image, wherein the inspection and judgment unit uses the read image as the correct answer image. (4) The image forming apparatus according to (3), wherein the inspection and judgment unit uses the read image for the first region and the printed data for the second region as the correct image.

[0007] (5) The image forming apparatus according to (1), wherein the first post-inspection processing unit and the second post-inspection processing unit do not reprint if the first area has an inspection error, and reprint if the second area has an inspection error. (6) The printed material is a variable print having a variable area and a fixed area, The image forming apparatus according to (5), wherein the first region is the fixed region and the second region is the variable region. (7) The image forming apparatus according to (1), further comprising a storage unit for storing the correct image, wherein the inspection and judgment unit performs OCR processing on the second region to detect text and compares it with the text data contained in the second region of the correct image stored in the storage unit.

[0008] (8) The image forming apparatus according to (7), wherein the second post-inspection processing unit performs image processing on the print data in the second region in response to inspection errors in comparison with text data and then reprints. (9) The image forming apparatus according to (7), wherein the second post-inspection processing unit changes the font of the print data in the second region and reprints it in response to inspection errors in comparison with text data. (10) The image forming apparatus according to (5), wherein the printed material has a spot color area and a non-spot color area, the first area being a spot color area and the second area being a non-spot color area.

[0009] (11) The image forming apparatus according to (1), wherein the first region is a non-printing region and the second region is a printing region, and the first post-inspection processing unit performs reprinting including cleaning of the image forming unit if the non-printing region has an inspection error, and the second post-inspection processing unit performs reprinting including color correction processing if the printing region has an inspection error. (12) The image forming apparatus according to (1), wherein the first post-inspection processing unit and the second post-inspection processing unit can separately set an upper limit on the number of reprints in response to an inspection error. (13) The image forming apparatus according to (1), wherein the first post-inspection processing unit and the second post-inspection processing unit can separately set whether or not to discard subsequent paper that has been fed in response to an inspection error, and, if so, the output unit to which the paper should be discarded.

[0010] (14) A control method for an image forming apparatus, comprising: an image reading unit reading an image of a printed material and acquiring a read image; an inspection determination unit comparing the read image read by the image reading unit with a correct image and making an inspection determination; a first post-inspection processing unit performing a first post-inspection processing for inspection errors in a first region of the read image; and a second post-inspection processing unit performing a second post-inspection processing different from the first post-inspection processing for inspection errors in a second region of the read image. (15) A control program for causing a computer to perform the following steps: a procedure for reading an image of a printed material and obtaining a read image; a procedure for comparing the read image read from the printed material with a correct image and making an inspection judgment; a procedure for performing a first post-inspection processing for inspection errors in a first region of the read image; and a procedure for performing a second post-inspection processing different from the first post-inspection processing for inspection errors in a second region of the read image. [Effects of the Invention]

[0011] According to the present invention, processing can be performed according to the area where the inspection error occurred, and for example, the consumption of consumables such as printing paper due to unnecessary reprinting or purging after inspection can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram illustrating the general arrangement of each device in the image forming apparatus according to the embodiment. [Figure 2A] This is a block diagram illustrating the hardware configuration of an image forming apparatus according to an embodiment. [Figure 2B] This is a block diagram illustrating the functional configuration of the inspection control unit according to the embodiment. [Figure 3] This is a schematic diagram illustrating image data in the first embodiment. [Figure 4] It is a schematic diagram exemplifying a read image in the first embodiment. [Figure 5] It is a schematic diagram exemplifying one of the correct images in the first embodiment. [Figure 6A] It is a schematic diagram exemplifying image data in the print job of the first embodiment. [Figure 6B] It is a table exemplifying job information in the print job of the first embodiment. [Figure 6C] It is a table exemplifying page information in the print job of the first embodiment. [Figure 7] It is a table exemplifying inspection setting information in the inspection of the first embodiment. [Figure 8] It is a schematic diagram exemplifying an inspection error in the first area in the first embodiment. [Figure 9] It is a schematic diagram exemplifying an inspection error in the second area in the first embodiment. [Figure 10] It is a flowchart exemplifying the processing flow in the first embodiment. [Figure 11] It is a schematic diagram exemplifying image data in the second embodiment. [Figure 12] It is a schematic diagram exemplifying a read image in the second embodiment. [Figure 13] It is a schematic diagram exemplifying a part of the correct image in the second embodiment. [Figure 14] It is a schematic diagram exemplifying the correct image in the second embodiment. [Figure 15A] It is a schematic diagram exemplifying image data in the print job of the second embodiment. [Figure 15B] It is a table exemplifying job information in the print job of the second embodiment. [Figure 15C] It is a table exemplifying page information in the print job of the second embodiment. [Figure 16] It is a table exemplifying inspection setting information in the inspection of the second embodiment. [Figure 17]This is a schematic diagram illustrating an inspection error in the first region in the second embodiment. [Figure 18] This is a schematic diagram illustrating an inspection error in the second region in the second embodiment. [Figure 19] This is a schematic diagram illustrating the contamination of the first region in the second embodiment. [Figure 20] This is a schematic diagram illustrating a variation in the second region in the second embodiment. [Figure 21] This is a flowchart illustrating the processing flow in the second embodiment. [Figure 22] This is a schematic diagram illustrating image data in the third embodiment. [Figure 23A] This is a schematic diagram illustrating image data in a print job according to the third embodiment. [Figure 23B] This is a table illustrating job information in a print job according to the third embodiment. [Figure 23C] This is a table illustrating page information in a print job according to the third embodiment. [Figure 24] This table illustrates the inspection setting information for the inspection in the third embodiment. [Figure 25] This is a schematic diagram illustrating an inspection error in the first region in the third embodiment. [Figure 26] This is a schematic diagram illustrating an inspection error in the second region in the third embodiment. [Figure 27] This is a flowchart illustrating the processing flow in the third embodiment. [Figure 28] This is a schematic diagram illustrating image data in the fourth embodiment. [Figure 29A] This is a schematic diagram illustrating image data in a print job according to the fourth embodiment. [Figure 29B] This is a table illustrating job information in a print job according to the fourth embodiment. [Figure 29C] This is a table illustrating page information in a print job according to the fourth embodiment. [Figure 30] This table illustrates the inspection setting information for the inspection in the fourth embodiment. [Figure 31] This is a schematic diagram illustrating an inspection error in a non-printed area in the fourth embodiment. [Figure 32] This is a schematic diagram illustrating an inspection error in the printing area in the fourth embodiment. [Figure 33] This is a flowchart illustrating the processing flow in the fourth embodiment. [Figure 34] This is a schematic diagram illustrating image data in the fifth embodiment. [Figure 35] This is a schematic diagram illustrating the image read in the fifth embodiment. [Figure 36] This is a schematic diagram illustrating a portion of the correct image in the fifth embodiment. [Figure 37] This is a schematic diagram illustrating the correct image in the fifth embodiment. [Figure 38A] This is a schematic diagram illustrating image data in a print job according to the fifth embodiment. [Figure 38B] This is a table illustrating job information in a print job according to the fifth embodiment. [Figure 38C] This is a table illustrating page information in a print job according to the fifth embodiment. [Figure 39] This table illustrates the inspection setting information for the inspection in the fifth embodiment. [Figure 40] This is a schematic diagram illustrating an inspection error in the second region in the fifth embodiment. [Figure 41] This table illustrates the OCR processing results for the second region in the fifth embodiment. [Figure 42] This is a schematic diagram illustrating the character thinning process in the fifth embodiment. [Figure 43] This is a schematic diagram illustrating the character smoothing process in the fifth embodiment. [Figure 44] This is a schematic diagram illustrating the character edge enhancement processing in the fifth embodiment. [Figure 45] This is a schematic diagram illustrating the character screen change process in the fifth embodiment. [Figure 46]This is a flowchart illustrating the processing flow in the fifth embodiment. [Figure 47] This is a flowchart illustrating the processing flow in the sixth embodiment. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments, and various design modifications are possible based on the claims. Furthermore, each embodiment can be combined as appropriate.

[0014] [First Embodiment] The image forming apparatus 1 according to the first embodiment will be described with reference to Figures 1 to 9. The image forming apparatus 1 is an image forming apparatus having an automatic inspection function. In the automatic inspection, the printed materials, etc., that have been image-formed are inspected for text content, color reproduction, stains, etc. Products that pass the inspection can be output separately from products that fail the inspection, etc. The image forming method can be an electrophotographic method, an electrostatic recording method, or an inkjet method. Below, an apparatus that performs image forming by the electrophotographic method will be described. As illustrated in Figure 1, the image forming apparatus 1 comprises a paper feeder 15, an image forming unit 14, a post-processing device 17, a control unit 10, an inspection device 16, and an operation unit 13. The image forming apparatus 1 may also include a document transport unit 11 and a document reading unit 12. The various components of the image forming apparatus 1 will be described below.

[0015] (Document transport unit and document reading unit) The image forming apparatus 1 may include a document transport unit 11 and a document reading unit 12. The document transport unit 11 is a device that automatically transports one or more sheets of document paper to the document reading unit 12. The document reading unit 12 is a device that optically reads images from the document paper. The document image data read by the document reading unit 12 can be used for image forming.

[0016] (Operation unit) The operation unit 13 is a device that allows the user to perform operations and input various settings related to the image forming apparatus 1. The operation unit 13 can also display information such as the status of the image forming apparatus 1 to the user. By making the operation unit 13 a touch panel, display and operation can be processed in parallel. The input of operations and the display may be provided as separate devices, and there are no particular restrictions on their location; for example, they may be located away from the image forming unit 14. The operation unit 13 may also be an external terminal such as a personal computer.

[0017] (Paper feeder) The paper feeder 15 is a device that stores image-forming recording media such as printing paper (hereinafter referred to as "paper") and feeds them to the next stage of the device. Here, the paper feeder 15 has two paper feeding sections 151 and 152 that store the paper and feeds the paper to the image forming section 14. The paper feeder 15 may have one paper feed section or three or more sections. Furthermore, the image forming apparatus 1 may be equipped with multiple paper feeders 15.

[0018] (Image forming unit) The image forming unit 14 is a device that forms an image on paper. Here, the components necessary for forming an image in an image forming apparatus that utilizes an electrophotographic image formation process are collectively referred to as the image forming unit. The image forming unit 14 consists of a photosensitive drum on which an electrostatic latent image is formed, a developer that develops the electrostatic latent image into a toner image, a transfer roller that transfers the developed toner image to the paper, and a fuser that fixes the transferred toner image to the paper by heat pressing or the like. The image forming unit 14 takes the image data of the original document read from the original document reading unit 12, or the image data generated from the print job received via the communication unit of the control unit 10 (hereinafter simply referred to as "image data," and sometimes as "print data"), and forms it on the paper transported from the paper feeding units 151 and 152, and then sends it to the next stage of the device.

[0019] (Post-processing device) The post-processing device 17 is a device that outputs paper sent from the preceding device. The post-processing device 17 has an output unit for loading paper. Then, based on instructions from the control unit 10, it transports the paper using transport rollers and switching claws and discharges it to the output unit. The post-processing device 17 can have multiple output units, and in this case, it has three output units 171, 172, and 173. This allows the paper to be sorted and output according to the results of inspection, etc. For example, the post-processing device 17 can output good products that have passed inspection (hereinafter sometimes referred to as "inspection OK") to the output unit 171, and output defective products that have failed inspection (hereinafter sometimes referred to as "inspection NG" or "inspection error") to the output units 172 and 173. Figure 1 illustrates the path 21 of the printed material read for generating the correct image before the start of inspection, the path 22 of good products after the start of inspection, and the path 23 of defective products after inspection. Furthermore, the post-processing device 17 may have a function to output the product after adding finishing processes desired by the user, such as stapling, punching, folding, cutting, and perforating.

[0020] (Inspection device) The inspection device 16 is a device for inspecting the image-formed paper. Here, the inspection device 16 inspects the paper transported from the image forming unit 14 according to the instructions of the control unit 10. The inspection device 16 can then separate the inspected printed materials into acceptable and unacceptable items and send them to the next stage of the device. Inspection refers to checking for abnormalities such as misaligned pages, stains, wrinkles, consistency of text content, and color reproduction, and determining whether the paper is acceptable or unacceptable. The inspection device 16 includes an image reading unit 161 and a storage unit 162. The image reading unit 161 is an image reading means that reads images from printed materials and acquires read images, and is a device that reads images on paper transported from the image forming unit 14. The storage unit 162 is a storage means that stores correct images used for inspection, and is a device that holds correct images. A correct image is an image that is referenced during inspection. The storage unit 162 can register and store multiple types of images as correct images.

[0021] (Control Unit) The control unit 10 is a device that controls each of the devices in the image forming apparatus 1. The control unit 10 controls each device in the image forming apparatus 1, from paper feeding to image forming and paper discharge. As illustrated in Figure 2A, the control unit 10 includes a central processing unit (CPU) 101, a hard disk drive (HDD) 102, a memory 103, a non-volatile memory 104, and a communication unit 105. These are connected to each other via a bus and are further connected to each device of the image forming apparatus 1.

[0022] The CPU 101 is a device that executes various programs. For example, in image formation, the CPU 101 rasterizes the print data on the memory 103 and generates bitmap data for cyan, magenta, yellow, and black (CMYK) for printing. Then, it transfers the generated data to the image forming unit 14. HDD102 is an auxiliary storage device that stores programs for the CPU101 to control each device, information regarding the processing functions of each device, and print jobs received from the document reading unit 12 and the communication unit 105.

[0023] Memory 103 and non-volatile memory 104 are main memory. Memory 103 temporarily stores print jobs and various data during the execution process of the CPU 101. Non-volatile memory 104 stores programs for starting each device. The communication unit 105 is a device responsible for communication with the outside world. The communication unit 105 is connected to a network via a local area network (LAN) cable or the like, and can establish a connection with external client computers and other devices to send and receive data such as print jobs and various statuses.

[0024] The control unit 10 receives print jobs from external client computers, etc., via the communication unit 105. The print job includes job information, page information, and information that forms the basis of image data. The control unit 10 loads and analyzes the print job on the memory 103. The control unit 10 also has the function of an image processing unit that analyzes the print job received from the communication unit 105 and generates image data. Job information is information common to the entire job, such as the number of pages, number of copies, and finishing process. Page information is information about each page, such as paper size and type, and whether it is color printing or not. Image data is data used for image formation in the image forming unit 14.

[0025] (Image data) Image data may have multiple regions. The control unit 10 can analyze the image data and determine the number of regions and their positions within the image data. As illustrated in Figure 3, the image data 30 has first regions 3011, 3021 and second regions 3012, 3022. Image data 30 is the image data for print job ID 00001230. In the drawing, a print job with job ID x is represented as IDx.

[0026] The first region 3011 and the second region 3012 are different regions in the image data and do not overlap. Here, the second region 3012 is a region with text arranged on a plain background, while the first region 3011 is a region without text and has a pattern throughout. The first region 3011 is positioned to surround the second region 3012. The same applies to the first region 3021 and the second region 3022. Furthermore, the multiple regions of the image data do not necessarily have to differ in the presence or absence of characters or patterns; for example, the same pattern may be continuous across the entire page. Even if the multiple regions of the image data do not differ in content, they can be distinguished by their coordinates in the image data, and the control unit 10 can identify the multiple regions. In addition, the image data may have three or more regions.

[0027] Image data 30 consists of two pages of data. The second area 3012 on the first page contains the characters "0123456789". The second area 3022 on the second page contains the character "A". The first area 3011 on the first page and the first area 3021 on the second page have different patterns. In the drawing, the symbol "Px / y" indicates that the total number of pages is y, and this is the image on page x. Furthermore, to distinguish between the image data used for image formation and the image read by the image reading unit 161, a solid line is drawn along the outer edge of the image data, and a dashed line is drawn along the outer edge of the read image.

[0028] (Correct image) The inspection control unit 50 of the control unit 10 performs inspection using the correct image registered in the storage unit 162. The inspection control unit 50 can register multiple different types of correct images in the storage unit 162. The inspection control unit 50 can register the image data included in the print job directly in the storage unit 162 as the first correct image. For example, the image data 30 may be registered directly as the correct image. The image read by the image reading unit 161 may be used as the correct answer image. The inspection control unit 50 can register the image read by the image reading unit 161 as a second correct answer image in the storage unit 162. As illustrated in Figure 4, here, a total of two pages of read images 40, having first regions 4011, 4021 and second regions 4012, 4022, have been acquired. The read image 40 is data read by the image reading unit 161 of the inspection device 16 from a printed material formed from image data 30. The inspection control unit 50 may register this read image 40 as the correct answer image.

[0029] As the correct answer image, a combination of the print data from one of the first and second regions and the image read by the other image reading unit 161 may be used. The inspection control unit 50 can register data combining the image data and the read image as a third correct answer image in the storage unit 162. Combining means, for example, extracting one of the first and second regions from the image data and the other from the read image, and then combining them. Here, the correct answer image 31 is generated by combining the first regions 4011 and 4021 of the read image 40 and the second regions 3012 and 3022 of the image data 30. In Figure 5, the first regions 3111 and 3121 are the data from the first regions 4011 and 4021 of the read image 40, and the second regions 3112 and 3122 are the data from the second regions 3012 and 3022 of the image data 30.

[0030] The first, second, and third correct images are the image data itself, images of printed materials read from the image data, or combinations thereof. Here, all are data based on image data 30 included in the print job with job ID 00001230. In addition to these, the correct images can also be images read by the document reading unit 12 or images transmitted from outside the image forming apparatus 1, or combinations thereof. Furthermore, the correct images can be generated in various other ways and selected and used according to the purpose.

[0031] When using a scanned image as the correct image, if a print job prints multiple copies, the scanned image of the first copy can be used as the correct image. That is, the image forming apparatus 1 scans the first copy with the image scanning unit 161 while printing and registers it as the correct image in the storage unit 162. Then, the second and subsequent copies can be scanned with the image scanning unit 161 while printing as inspection targets and compared with the correct image for inspection. By using the scanned image of a preceding printed material as the correct image, the image forming apparatus 1 can effectively utilize materials and other resources. Furthermore, the image forming apparatus 1 may choose not to use the first read image as the correct image, but instead perform a separate print to use as the correct image, allowing the print job to proceed in various ways.

[0032] (Inspection) The control unit 10 instructs the image forming unit 14 to form an image based on the print job. It then instructs the inspection device 16 and performs inspection in cooperation with the inspection device 16. Inspection can be performed by comparing the printed material to be inspected with a correct image, that is, an image used as a reference during inspection. The control unit 10 includes an inspection control unit 50. The inspection control unit 50 is a means responsible for controlling the inspection process. As illustrated in Figure 2B, the inspection control unit 50 includes an inspection determination unit 55, a first post-inspection processing unit 51, and a second post-inspection processing unit 52.

[0033] The inspection and judgment unit 55 is a means for making an inspection judgment by comparing the read image read by the image reading unit 161 with the correct image. Note that the inspection judgment is a determination of whether the inspection passed or failed. The first post-inspection processing unit 51 is a means for controlling the first post-inspection processing for inspection errors in the first region. The second post-inspection processing unit 52 is a means for controlling the second post-inspection processing for inspection errors in the second region. The inspection and judgment unit 55 compares the correct image registered in the storage unit 162 of the inspection device 16 with the image of the printed material read by the image reading unit 161, for example, on the storage unit 162, and detects the difference between the two images. Then, if the difference is below a predetermined threshold, it determines that the inspection is OK, and if it exceeds the threshold, it determines that the inspection is NG. This will be explained with a specific example.

[0034] As illustrated in Figures 6A to 6C, print job ID 00001234 includes image data 41, job information 61, and page information 62. Image data 41 is the same as that of print job ID 00001230. According to job information 61, the number of pages is 2, the number of copies is 1, and automatic inspection is on. Note that inspection is performed when automatic inspection is on, and not when it is off. According to page information 62, the paper size is A4, the paper type is plain paper, the paper feed tray is the paper feed unit 151, the output tray is the output unit 171, and the duplex parameter is set to single-sided, i.e., single-sided printing. According to job information 61, the correct image number is 00001230. This means that in inspection, the correct image based on image data 41 included in print job ID 00001230 will be used. The method for generating the correct image is not particularly limited and can be, for example, the first, second, or third correct image described above.

[0035] When automatic inspection is enabled in the job information 61, the inspection and judgment unit 55 analyzes the area of ​​the image data 41 and determines the presence and arrangement of multiple areas. Here, it is determined that the image data 41 has two areas: a first area 4111, 4121 and a second area 4112, 4122. The inspection and judgment unit 55 then compares the read image of the printed material formed by print job ID 00001234 with the correct image. In the comparison, differences between the two images are detected. Differences in the images can be detected by focusing on, for example, the distribution of pixels with different brightness, pixel misalignment, and differences in chromaticity. The inspection and judgment unit 55 then determines whether the inspection is successful or not for each of the first and second areas using different judgment conditions. The inspection judgment unit 55 performs inspection by referring to the inspection setting information stored in the HDD 102. The inspection setting information is information that summarizes the settings for the inspection judgment conditions and the processing to be performed after an inspection error occurs. As illustrated in Figure 7, in this case, the inspection setting information 63 includes inspection judgment condition information, inspection error display information, and inspection reprint information.

[0036] The inspection judgment condition information represents the criteria for inspection, i.e., the strictness of the inspection, and can be set to five levels, for example, from level 1 to level 5. Levels 1 to 5 have different thresholds for determining whether an inspection is OK based on the difference from the correct image. Level 5 is the strictest, and level 1 is the lenient. The inspection judgment condition information can be set separately for each region. That is, the pass / fail judgment can be made for the first region and the second region using different judgment conditions. In this case, the first region is set to level 3, and the second region is set to level 5. For example, Level 5 determines that inspection is OK if the percentage of pixels that do not match the correct pixels is 3% or less. Similarly, Level 4 determines it as OK if it is 5% or less, Level 3 as OK if it is 10% or less, Level 2 as OK if it is 20% or less, and Level 1 as OK if it is 40% or less. The threshold for determining whether inspection is OK can be freely set by the user.

[0037] The inspection error display information represents the content of the inspection error detection display that is shown on the operation unit 13 when an inspection error occurs. Here, if an inspection error occurs in the first area, the message "An inspection error has occurred. Reprinting in progress." is displayed, and if an inspection error occurs in the second area, the message "An inspection error has occurred. Printing has stopped." is displayed. The inspection reprint information represents the subsequent processing, i.e., the content of post-inspection processing, in the event of an inspection error (inspection failure). Inspection reprint information can be set separately for each region. This allows the inspection control unit 50 to perform different post-inspection processing depending on the region where the inspection error was detected. Specifically, the first post-inspection processing unit 51 performs a first post-inspection processing step for inspection errors in the first region, and the second post-inspection processing unit 52 performs a second post-inspection processing step for inspection errors in the second region. The second post-inspection processing step can be different from the first post-inspection processing step. The post-inspection processing for cases where an inspection error is detected in the first area and in the second area will be explained in detail with reference to Figures 8 and 9.

[0038] As illustrated in Figure 8, in the read image 42 obtained by reading the printed material with the image reading unit 161, an inspection error 42111 is detected in the first region 4211, but not in the other first regions 4221, second regions 4212, and 4222. Referring to the inspection reprint information in the inspection setting information 63, the first region is set to "Purge defective / unnecessary paper to the output unit 172, then reprint. Reprinting is limited to 3 times." Defective paper refers to the page where the inspection error occurred, for example, page 1, and unnecessary paper refers to the page following the page where the inspection error occurred, for example, page 2. Purge means outputting (discarding) unnecessary paper such as defective paper or unnecessary paper. The first post-inspection processing unit 51 outputs the defective / unnecessary paper to the output unit 172 and instructs each device to reprint from the page where the inspection error occurred.

[0039] At this time, if there are already image-formed sheets of paper or sheets that have been fed, they are purged into the output unit, and then reprinting begins from the page where the inspection error occurred. In this case, since reprinting starts from the first page where the inspection error occurred, to prevent the page order from being disrupted, the second sheet that has already been fed is output to the output unit 172, and then reprinting starts from the first page. Furthermore, even if another inspection error occurs, the setting allows for reprinting to be repeated up to three times. If an inspection error still occurs on the fourth inspection, printing is stopped.

[0040] On the other hand, as illustrated in Figure 9, in the read image 43, an inspection error 43121 is detected in the second region 4312, but not in the other second region 4322 and the first regions 4311 and 4321. Referring to the inspection reprint information in the inspection setting information 63, the setting for the second region is "Purge defective / unnecessary paper to the output unit 173, then stop printing." The second inspection post-processing unit 52 instructs each device to output the defective page that resulted in an inspection error in the second region, for example, page 1, and the subsequent unnecessary page, for example, page 2, to the output unit 173, and then stop printing. This is a process to stop printing when it is not expected that the inspection error will be resolved even if reprinting is performed. Furthermore, the output destination for purging defective and unwanted paper is changed depending on whether the inspection error occurs in the first or second area. This allows for visual confirmation of the occurrence of inspection errors on the printed material.

[0041] The image forming apparatus 1 can perform different post-inspection processing depending on the region where the inspection error occurred, such as not reprinting if one of the first or second regions has an inspection error, but reprinting if the other region has an inspection error. Furthermore, in the post-inspection processing, it is possible to separately set whether or not to discard subsequent paper that has already been fed for each inspection error in the first area and the second area, and if discarding is necessary, the output unit to which the paper is discarded can also be set separately.

[0042] The image forming apparatus 1 according to the first embodiment, having the configuration described above, can perform optimal inspection and corresponding processing by applying different error judgment conditions, error detection display, and post-inspection processing such as reprinting to multiple regions of image data for each region. In print jobs, multiple areas of image data may have different properties, such as variable data printing or spot color areas. If the same judgment criteria are applied to the entire print job in such cases, some areas may be judged too strictly or too leniently. Furthermore, simply reprinting after an inspection error may not resolve the root cause of the error, resulting in wasted equipment and consumables such as printing paper.

[0043] Traditionally, even though a print job contained multiple areas with different characteristics, the same error judgment conditions, error detection displays, and reprint processes were applied to all areas. The image forming apparatus 1 can optimize the pass / fail judgment of the inspection and the post-inspection processing by applying different error judgment conditions to each region and performing post-inspection processing.

[0044] Furthermore, it is possible to reprint regardless of the area where the inspection error occurred, and in that case, the upper limit of the number of reprints can be set separately. Even in this way, different post-inspection processing can be performed depending on the area where the inspection error occurred. Alternatively, the inspection control unit 50 may skip registering the correct image in the storage unit 162 and perform the inspection by acquiring the correct image each time, i.e., on a case-by-case basis, without using the correct image registered in the storage unit 162. The inspection determination unit 55 can compare the read image and the correct image acquired each time an inspection is performed on the memory 103.

[0045] Next, the inspection process in the image forming apparatus 1 will be explained with reference to Figure 10. Figure 10 illustrates a process in which a registered correct image is used to inspect a print job, comparing it to the registered correct image while printing. First, when the control unit 10 receives a print job containing image data via the communication unit 105 (step S101: Yes), it expands and analyzes the job information, page information, and image data in the print job on the memory 103 (step S102). Then, if automatic inspection is enabled in the job information (step S103: Yes), the inspection determination unit 55 analyzes the area included in the image data (step S104). If automatic inspection is not enabled in the job information (step S103: No), it performs normal printing processing (step S191).

[0046] If the image data reveals that there are multiple regions (Step S105: Yes), the inspection control unit 50 starts a different inspection process for each region (Step S106). If the image data reveals that there are no multiple regions (Step S105: No), the normal inspection process is performed (Step S192). Note that the normal printing process is a known printing process, and the normal inspection process is a known inspection process. Then, in the first area (step S107: first area), the inspection judgment unit 55 refers to the inspection judgment condition information stored in the HDD and executes the inspection judgment conditions for the first area (step S111). If no inspection errors are detected as a result (step S112: No), the process in Figure 10 is terminated. If an inspection error is detected (step S112: Yes), the first post-inspection processing unit 51 refers to the inspection error display information stored in the HDD and displays the inspection error for the first area on the operation unit 13 (step S113). It also refers to the inspection reprint information stored in the HDD and performs reprinting for the first area (step S114), terminating the process in Figure 10.

[0047] Meanwhile, in the second area (step S107: second area), the inspection judgment unit 55 refers to the inspection judgment condition information stored in the HDD and executes the inspection judgment conditions for the second area (step S121). If no inspection errors are detected as a result (step S122: No), the process in Figure 10 is terminated. If an inspection error is detected (step S122: Yes), the second post-inspection processing unit 52 refers to the inspection error display information stored in the HDD and displays the inspection error for the second area on the operation unit 13 (step S123). Then, it refers to the inspection reprint information stored in the HDD and performs reprinting for the second area (step S124), terminating the process in Figure 10.

[0048] [Second Embodiment] Next, the image forming apparatus according to the second embodiment will be described with reference to Figures 11 to 20. The printed material of the second embodiment is a variable print having a variable region and a fixed region. In the second embodiment, the print job is a print job for a variable print (hereinafter sometimes referred to as a "variable job") and has multiple records. Therefore, the correct image is different from that of the first embodiment. And, as with the first embodiment, different post-inspection processing is performed depending on whether the region where the inspection error occurred is the first region or the second region. The hardware configuration is the same as in the first embodiment. The following will be explained with specific examples.

[0049] (Correct image) As illustrated in Figure 11, the image data 44 for print job ID 00001301 consists of three records 441, 443, and 445. Each record consists of two pages and corresponds to individual data for variable printing. The image data 44 consists of a total of six pages of data. Each record corresponds to one individual data point. That is, each record has different variable areas, while sharing a common fixed area. Here, the first areas 4411 and 4421 are the fixed areas of the variable print, and the second areas 4412 and 4422 are the variable areas. Note that the first and second areas of records 443 and 445 have the same arrangement as record 441, and the reference numerals are omitted in the drawing.

[0050] The variable areas of record 441, specifically the second areas 4412 and 4422, contain the characters "0123456789" on the first page and "A" on the second page. The variable area of ​​record 443 contains the characters "abcdefghij" on the first page and "B" on the second page. The variable area of ​​record 445 contains the characters "ABCDEFGHIJ" on the first page and "C" on the second page. The fixed areas 4411 and 4421 of record 441 have different patterns on the first and second pages. The same applies to the other records 443 and 445. The patterns on the first and second pages are the same across records. In the diagram, the symbol "Px / y" at the top of each page indicates that the total number of pages for all records is y, and this is the image on page x. The symbol "Px / y" at the bottom of each page indicates that the total number of pages for the print job is y, and this is the image on page x.

[0051] The correct image is generated from a scanned image of a portion of the printed material. Here, as illustrated in Figure 12, the inspection control unit 50 reads the printed material, which has the first record (record 441) of the image data 44 as an image, using the image reading unit 161 of the inspection device 16, and obtains record 452 of the scanned image 45. As illustrated in Figure 13, the inspection control unit 50 extracts data from the fixed first regions 4511 and 4521 from the read image 45 and uses this data as the first region 3211 and 3221 data of record 321 in the intermediate data 32. The data from the second regions 4512 and 4522 is not used, and the intermediate data 32 does not contain data from the second regions 3212 and 3222. The intermediate data 32 is stored in the storage unit 162 as the correct image of the first region (fixed region) common to all records. Then, during inspection, the inspection control unit 50 generates the correct image while receiving the print job to be inspected. Here, the final correct image 33 for all records is generated by combining the data from the second region (variable region) of the image data 44 with the intermediate data 32.

[0052] In Figure 14, the data in the first area 3311, 3321 of record 331 and the first area of ​​records 332, 333 are the data in the first area of ​​intermediate data 32. Also, the data in the second area 3312, 3322 of record 331 and the second area of ​​records 332, 333 are the data in the second area of ​​the corresponding records 441, 443, 445 in image data 44.

[0053] (Print job) As illustrated in Figures 15A to 15C, the print job ID 00001335 subject to inspection includes image data 46, job information 64, and page information 65. In the image data 46, record 461 has first areas 4611 and 4621 and second areas 4612 and 4622. Records 463 and 465 also have first and second areas. Furthermore, as illustrated in Figure 16, the inspection setting information 66 contains inspection reprint information for both the variable job fixed area (first area) and the variable job variable area (second area). Although not shown in Figure 16, the error judgment conditions and error detection display can also be set differently for each area.

[0054] The inspection and judgment unit 55 can determine from the job type in the job information 64 that this job is a variable print job, and from the record number and page number in the page information 65 that it is a 2-page, 3-record job. It can also identify the positions of fixed and variable areas on each page from the image data 46. The correct image number in the job information 64 is 00001301, and the correct image based on the image data 44 included in print job ID 00001301 is specified. The correct image based on image data includes the image data as is, an image of the printed material read from the image data, or a combination of these. Here, the correct image 33 in Figure 14 is used.

[0055] (Post-inspection processing) As illustrated in Figure 17, in the read image 80 of the print job ID 00001335, record 801 has first areas 8011 and 8021, and second areas 8012 and 8022. Records 803 and 805 also have first and second areas, respectively. Inspection error 80111 is detected in the fixed area, first area 8011. In this case, the first post-inspection processing unit 51 refers to the inspection setting information 66 and instructs each device to purge defective / unnecessary paper to the output unit 172 and reprint from the page where the inspection error occurred. On the other hand, as illustrated in Figure 18, in the read image 81, record 811 has first regions 8111 and 8121, and second regions 8112 and 8122. Records 813 and 815 also have first and second regions, respectively. Inspection error 81121 is detected in the variable region, second region 8112. In this case, the second post-inspection processing unit 52 instructs each device to purge the defective / unnecessary paper to the output unit 173 and stop printing.

[0056] In Figure 19, in the read image 82, record 821 has a first area 8211, 8221 and a second area 8212, 8222. Records 823 and 825 also have a first area and a second area, respectively. The inspection error 82111 in the fixed area (first area) is caused by dirt. If the cause of the inspection error is dirt, it can often be resolved by reprinting, and normal printing can be restored. For this reason, the post-inspection processing for inspection errors in the fixed area (first area) is to reprint. On the other hand, in Figure 20, in the read image 83, record 831 has a first area 8311, 8321 and a second area 8312, 8322. Records 833 and 835 also have a first area and a second area, respectively. In the second area 8312, which is a variable area where inspection error 83121 occurred, the characters should be "0123456789" but are "abcdefghij". In cases like this, where an inspection error occurs due to a data error or misalignment, simply reprinting will not restore normal printing. Therefore, for inspection errors in the variable area (second area), the post-inspection processing involves stopping printing instead of reprinting.

[0057] The image forming apparatus according to the second embodiment can perform optimal inspection and corresponding processing in the case of variable prints having fixed and variable regions by applying different error judgment conditions, error detection display, and post-inspection processing such as reprinting for each region. When printing many copies with the same content, print quality can be checked by creating "correct image" data from successfully printed copies and comparing all copies to this correct image. However, in the case of variable data printing, for example, copies printed with individual data such as addresses and names have no other use, and if image generation is performed on all pages of one job to generate the correct image, the entire job's worth of prints will be wasted.

[0058] The image forming apparatus according to the second embodiment can improve the efficiency of inspection when the print job is a variable print by generating a correct image by combining the read image of the printed material for a fixed area and the image data of the variable area before printing. Furthermore, by applying different error judgment conditions, error detection display, and post-inspection processing such as reprinting for each area, optimal inspection and response processing for inspection errors can be performed.

[0059] Alternatively, you may use image data from a print job directly as the correct answer image. Furthermore, the first and second regions can be interchanged, with one of them corresponding to a fixed region and the other to a variable region.

[0060] Next, the inspection process flow in the second embodiment will be explained with reference to Figure 21. Figure 21 illustrates a process in which the read image of the first region has already been registered, a correct image is generated while the print job is progressing, and the print job to be inspected is printed while being inspected. The correct image can be generated by combining the read image of the first region with data from the second region extracted from the image data.

[0061] First, if the inspection judgment unit 55 detects an inspection error during inspection printing (step S201: Yes), it expands and analyzes the job information, page information, and image data in the print job on the memory 103 (step S202). If no inspection error is detected (step S201: No), the control unit 10 continues the normal printing process (step S291). If this job is a variable job (step S203: Yes), the inspection determination unit 55 analyzes the location of the inspection error (step S204). If this job is not a variable job (step S203: No), the inspection control unit 50 performs normal inspection processing (step S292).

[0062] If the inspection error is only in the fixed area of ​​the variable job (step S205: fixed area only), the first post-inspection processing unit 51 refers to the inspection reprint information stored in the HDD and performs the reprint process (step S211), and terminates the process shown in Figure 21. If the inspection error location includes a variable area of ​​a variable job (step S205: including variable area), the second post-inspection processing unit 52 refers to the inspection reprint information stored in the HDD, cancels printing (step S221), and terminates the process shown in Figure 21.

[0063] In the inspection process flow of the second embodiment (Figure 21), the location of the inspection error is analyzed after an inspection error occurs. Alternatively, in the second embodiment, the inspection can be performed after determining the area to be inspected, as in the process flow of the first embodiment (Figure 10). The inspection control unit 50 can then perform inspections on the first and second areas using different judgment conditions and perform different post-inspection processing. The same applies to the inspection process flows of the third and fourth embodiments.

[0064] [Third Embodiment] Next, the image forming apparatus according to the third embodiment will be described with reference to Figures 22 to 26. The printed material of the third embodiment has a spot color area and a non-spot color area. In the third embodiment, the print job includes a spot color area. The spot color area is an area where high color reproducibility is required. And, as with the first embodiment, different post-inspection processing is performed depending on whether the area where the inspection error occurred is the first area or the second area. The hardware configuration is the same as in the first embodiment. A specific example will be described below.

[0065] (Correct image) As illustrated in Figure 22, the image data 47 for print job ID 00001430 consists of two pages and has a first area 4701, 4711 and a second area 4702. The first areas 4701 and 4711 are areas other than the spot color area (hereinafter sometimes referred to as the "non-spot color area"), and the second area 4702 is the spot color area. The correct image can be the first, second, and third correct images described in the first embodiment, that is, the image data as is, the image of the printed material read from the image data, or a combination thereof. Here, the correct image is the image data 47 as is.

[0066] (Print job) As illustrated in Figures 23A to 23C, the print job ID 00001436 subject to inspection includes image data 48, job information 67, and page information 68. Furthermore, as illustrated in Figure 24, the inspection setting information 69 contains inspection and reprint information for both the non-spot color area (first area) and the spot color area (second area). Although not shown in Figure 24, the error judgment conditions and error detection display can also be set differently for each area. The inspection and judgment unit 55 can determine from the job type in the job information 67 that this job is a spot color print including a spot color area, and from the page number in the page information 68 that it is a two-page job. It can also identify the positions of non-spot color areas and spot color areas on each page from the image data 48. The correct image number in the job information 67 is 00001430, and the correct image is specified based on the image data 47 included in print job ID 00001430.

[0067] (Post-inspection processing) If the area where an inspection error is detected is a non-special color area (first area), the first post-inspection processing unit 51 refers to the inspection setting information 69, purges the defective / unnecessary paper to the output unit 172, and performs color correction processing (automatic color correction). Then, it instructs each device to reprint from the page where the inspection error occurred. On the other hand, if the area where the inspection error was detected is the spot color area (second area), the second post-inspection processing unit 52 instructs each device to purge the defective / unnecessary paper to the output unit 173 and stop printing.

[0068] In Figure 25, the scanned image 34 of the print job ID 00001436 has non-spot color areas 3401 and 3411 and a spot color area 3402. A cyan gradation defect inspection error 3403 occurred in the non-spot color area (first area) 3401. Areas other than spot colors are easily restored to the normal color range by automatic color adjustment, even if some color variation occurs. Therefore, for inspection errors in the non-spot color area (first area), the post-inspection processing involves reprinting after automatic color adjustment. On the other hand, in Figure 26, the scanned image 35 has non-spot color areas 3501 and 3511 and a spot color area 3502. A gradation error 3503 occurred in the spot color area (second area) 3502. Spot color areas are used for printing important objects such as corporate logos, and even slight color variations are unacceptable, so strict calibration must be redone. For this reason, a post-inspection process of stopping printing is performed for inspection errors in the spot color area (second area).

[0069] The image forming apparatus according to the third embodiment can perform optimal inspection and error handling by applying different post-inspection processing, such as error detection conditions, error detection display, and reprinting, to each area when the print job includes a spot color area. Furthermore, the first and second regions can be interchanged, with one of them corresponding to a feature region and the other to a non-feature region.

[0070] Next, the inspection process flow in the third embodiment will be explained with reference to Figure 27. Figure 27 illustrates a process in which the correct image has already been registered, and the print job to be inspected is printed while being inspected by comparing it with the registered correct image.

[0071] First, if the inspection judgment unit 55 detects an inspection error during inspection printing (step 301: Yes), it expands and analyzes the job information, page information, and image data in the print job on the memory 103 (step S302). If no inspection error is detected (step S301: No), the control unit 10 performs normal printing processing (step S391). If the job includes a spot color area (Step S303: Yes), the inspection determination unit 55 analyzes the location of the inspection error (Step S304). If the job does not include a spot color area (Step S303: No), the inspection control unit 50 performs a reprint process as a normal inspection process (Step S392). If the inspection error location is only in a non-spot color area (Step S305: Non-spot color area only), the first post-inspection processing unit 51 refers to the inspection reprint information stored in the HDD, performs automatic color correction, and then executes the reprint process (Step S311), ending the process shown in Figure 27. If the inspection error location includes a spot color area (Step S305: Includes variable area), the second post-inspection processing unit 52 refers to the inspection reprint information stored in the HDD, cancels printing (Step S321), and ends the process shown in Figure 27.

[0072] [Fourth Embodiment] Next, the image forming apparatus according to the fourth embodiment will be described with reference to Figures 28 to 32. The printed material of the fourth embodiment has a printable area and a non-printable area. That is, in the fourth embodiment, the print job includes a non-printable area. The non-printable area is an area where image formation does not occur. The image read by the image reading unit is compared with the correct image to determine whether the inspection is successful or not, and different post-inspection processing is performed depending on whether the area where the inspection error occurred is a printable area or a non-printable area. The hardware configuration is the same as in the first embodiment. The following will be explained with specific examples.

[0073] (Correct image) As illustrated in Figure 28, the image data 49a for print job ID 00001530 consists of two pages and has a non-printable area 4915 and printable areas 4916, 4925, and 4926. Here, the first area is referred to as the non-printable area and the second area as the printable area. The correct answer image can be the first, second, and third correct answer images described in the first embodiment, that is, the image data as is, the image of the printed material read from the image data, or a combination thereof. The combination is a combination of one of the printed area and non-printed area in the image data and the other of the printed area and non-printed area in the read image. Here, the correct answer image is the data of image data 49a as is.

[0074] (Print job) As illustrated in Figures 29A to 29C, the print job ID 00001537 subject to inspection includes image data 49b, job information 70, and page information 71. Furthermore, as illustrated in Figure 30, the inspection setting information 72 contains inspection and reprint information for both the printable and non-printable areas. Although not shown in Figure 30, error judgment conditions and error detection displays can also be set differently for each area. The inspection and judgment unit 55 can determine from the job type in the job information 70 that this job is a normal print job, and from the page number in the page information 71 that it is a two-page job. It can also identify the positions of the printable and non-printable areas on each page from the image data 49b. The correct image number in the job information 70 is 00001530, and the correct image is specified based on the image data 49a included in print job ID 00001530.

[0075] (Post-inspection processing) In Figure 31, the scanned image 36 of the print job ID 00001537 has a non-printable area 3615 and printable areas 3616, 3625, and 3626. An inspection error 3617 is detected in the non-printable area 3615. In this case, the first post-inspection processing unit 51 refers to the inspection setting information 72, purges the defective / unnecessary paper to the output unit 173, and performs cleaning of the image forming unit 14 without performing color correction processing (automatic color correction). It then instructs each device to reprint from the page where the inspection error occurred. The cleaning process involves removing stubborn dirt from transfer rollers, fusers, and other components by rotating the rollers or passing paper through them while a cleaning blade is applied. If the cleaning process does not resolve the issue, other causes may be at play, so reprinting is limited to two attempts.

[0076] On the other hand, in Figure 32, the read image 37 has a non-printable area 3715 and printable areas 3716, 3725, and 3726. An inspection error 3717 is detected in the printable area 3716. In this case, the second post-inspection processing unit 52 purges the defective / unnecessary paper to the output unit 172 and performs automatic color correction. It then instructs each device to reprint from the page where the inspection error occurred. Reprinting is limited to three times. In this way, the maximum number of reprints is changed depending on whether the area where the inspection error was detected is a printable area or a non-printable area.

[0077] Since there are no print objects in the non-printable area, color variations are not a concern. Therefore, color correction processing is not performed. Instead, a cleaning process is performed and reprinting is carried out as a post-inspection process, as dirt and other imperfections may be the cause of inspection errors. On the other hand, if color variations occur in the printed area, automatic color adjustment can often restore the colors to within the normal range. Therefore, the post-inspection process involves reprinting after automatic color adjustment.

[0078] The image forming apparatus according to the fourth embodiment can perform optimal inspection and error handling by applying different post-inspection processing, such as error determination conditions, error detection display, and reprinting, to each area when the print job includes a non-printing area.

[0079] Next, the inspection process flow in the fourth embodiment will be explained with reference to Figure 33. Figure 33 illustrates a process in which the correct image has already been registered, and the print job to be inspected is printed while being inspected by comparing it with the registered correct image. First, if the inspection judgment unit 55 detects an inspection error during inspection printing (step S401: Yes), it expands and analyzes the job information, page information, and image data in the print job on the memory 103 (step S402). If no inspection error is detected (step S401: No), the control unit 10 performs normal printing processing (step S491).

[0080] If the job includes non-printable areas (Step S403: Yes), the inspection determination unit 55 analyzes the locations of inspection errors (Step S404). If the job does not include non-printable areas (Step S403: No), the inspection control unit 50 performs reprinting as a normal inspection process (Step S492). If the inspection errors are only in non-printable areas (Step S405: Non-printable areas only), the first post-inspection processing unit 51 refers to the inspection reprint information stored in the HDD 102, performs cleaning without automatic color correction, and executes reprinting (Step S411), and the process in Figure 33 is completed. If the inspection error location includes a printable area (step S405: printable area included), the second post-inspection processing unit 52 refers to the inspection reprint information stored in the HDD 102, performs automatic color correction, and executes the reprint process (step S421), and the process shown in Figure 33 is completed.

[0081] [Fifth Embodiment] Next, the image forming apparatus according to the fifth embodiment will be described with reference to Figures 34 to 46. In the image forming apparatus according to the fifth embodiment, when determining one of the first and second regions, the image reading means recognizes text from the image by OCR processing and compares it with the text contained in the print data. Then, in response to inspection errors in the text comparison, image processing is performed on the print data of the affected region and reprinting is performed. In the first embodiment, the correct image was the image data itself, an image of a printed document read from the image data, or a combination thereof. The fifth embodiment differs from the first embodiment in that it performs optical character recognition (OCR) processing on areas containing characters to extract the string, and then compares the extracted string with the string in the text data of the print job to be inspected (record data in a variable job). Furthermore, if the string on the paper to be inspected cannot be recognized by the OCR processing, various image processing is performed and the document is reprinted. The hardware configuration is the same as in the first embodiment. The following will explain with specific examples.

[0082] (Correct image) As illustrated in Figure 34, the image data 85 for print job ID 00001602 consists of three records 851, 853, and 855. Each record consists of two pages and corresponds to individual data for variable printing. The image data 85 consists of a total of six pages of data. Each record corresponds to one individual data point. That is, each record has different variable areas, while sharing a common fixed area. Here, the first areas 8511 and 8521 are the fixed areas of the variable print, and the second areas 8512 and 8522 are the variable areas. Note that the first and second areas of records 853 and 855 have the same arrangement as record 851, and the reference numerals are omitted in the drawing.

[0083] The variable areas of record 851, specifically the second areas 8512 and 8522, contain the characters "0123456789" on the first page and "A" on the second page. The variable area of ​​record 853 contains the characters "abcdefghij" on the first page and "B" on the second page. The variable area of ​​record 855 contains the characters "ABCDEFGHIJ" on the first page and "C" on the second page. The fixed areas 8511 and 8521 of record 851 have different patterns on the first and second pages. The same applies to the other records 853 and 855. The patterns on the first and second pages are the same across records.

[0084] The correct image is generated from a scanned image of a portion of the printed material. Here, as illustrated in Figure 35, the inspection control unit 50 reads the printed material, which has the first record (record 851) of the image data 85 formed as an image, using the image reading unit 161 of the inspection device 16, and obtains record 381 of the scanned image 38. As illustrated in Figure 36, the inspection control unit 50 extracts data from the fixed first regions 3811 and 3821 from the read image 38 and uses this data as the first region 8611 and 8621 data of record 861 in the intermediate data 86. The data from the second regions 3812 and 3822 is not used, and the intermediate data 86 does not contain data from the second regions 8612 and 8622. The intermediate data 86 is stored in the storage unit 162 as the correct image of the first region (fixed region) common to other records. In the correct image 87 for all pages illustrated in Figure 37, the data from the first region 8711 and 8721 of record 871 and the first region of records 873 and 875 are the data from the first region of the intermediate data 86.

[0085] On the other hand, the correct image 87 does not contain data in the second region 8712, 8722 of record 871 and the second region of records 873, 875. For the second region (variable region), no correct image is generated, and the string read by OCR processing is compared with the text data of the print job. The inspection judgment unit 55 performs inspection of the first region (fixed region) by comparing it with the correct image 87 based on print job ID 00001602, and inspection of the second region (variable region) by comparing it with the text data of print job ID 00001666.

[0086] (Print job) As illustrated in Figures 38A to 38C, the print job ID 00001666 subject to inspection includes image data 88, job information 73, and page information 74. In the image data 88, record 881 has first areas 8811 and 8821 and second areas 8812 and 8822. Other records 883 and 885 also have first and second areas. Furthermore, as illustrated in Figure 39, the inspection setting information 75 contains inspection reprint information for both the variable job fixed area (first area) and the variable job variable area (second area). Although not shown in Figure 39, the error judgment conditions and error detection display can also be set differently for each area.

[0087] The inspection and judgment unit 55 can determine from the job type in the job information 73 that this job is a variable print job, and from the record number and page number in the page information 74 that it is a 2-page, 3-record job. In addition, the text data of the print job is stored as variable data in the page information 74. Here, module M101 corresponds to the data for the first page, and module M201 corresponds to the data for the second page. Then, the positions of the fixed and variable regions on each page can be identified from the image data 88. The correct image number in the job information 73 is 00001602, and the correct image based on the image data 85 included in print job ID 00001602 is specified. Here, the correct image 87 in Figure 37 is used as the correct image for the fixed region (first region).

[0088] (Post-inspection processing) If the area where the inspection error occurred is a fixed area (first area), the first post-inspection processing unit 51 refers to the inspection setting information 75 and instructs each device to purge the defective / unnecessary paper to the output unit 173 and reprint from the page where the inspection error occurred. Reprinting is limited to three times. On the other hand, as illustrated in Figure 40, in the read image 39 of the print job ID 00001666, record 391 has first regions 3911 and 3921, and second regions 3912 and 3922. Records 393 and 395 also have first and second regions, respectively. Inspection error 39121 is detected in the variable region, second region 3912. In this case, the second post-inspection processing unit 52 refers to the inspection setting information 75 and instructs each device to purge defective / unnecessary paper to the output unit 173, perform the thinning process, and stop printing. Reprinting is limited to one time.

[0089] Inspection errors in the fixed area (first area) can often be resolved by reprinting, allowing for a return to normal printing. Therefore, reprinting is the post-inspection processing method for inspection errors in the fixed area (first area). On the other hand, during inspection of the variable region (second region), the OCR-processed image 76 shown in Figure 41 exhibits an inspection error 761 due to character mismatch. Since the characters were not read correctly by the OCR process, it is possible that the cause is character distortion or similar issues, as seen in the inspection error 39121 in the read image 39 shown in Figure 40.

[0090] If the cause of the inspection error is distorted characters, it can sometimes be resolved by thinning the lines. As illustrated in Figure 42, thinning the lines makes the characters 572 after processing thinner overall compared to the characters 571 before processing, which can resolve inspection errors. For this reason, the post-inspection process involves performing thinning image processing followed by reprinting.

[0091] The image forming apparatus according to the fifth embodiment can improve the accuracy of inspection when a print job includes text such as variable print. For fixed areas, it generates a correct image based on the read image of the printed material, and for variable areas, it compares the OCR processed data of the printed material with the text data of the print job. Furthermore, by applying different error judgment conditions, error detection display, and post-inspection processing such as reprinting for each area, it is possible to perform optimal inspection and response processing to inspection errors.

[0092] In addition to thinning, other image processing techniques to improve character recognition include smoothing, edge enhancement, and screen adjustment. These image processing techniques are applied to variable regions. As illustrated in Figure 43, the smoothing process makes the outer edge of the processed character 574 smoother than the original character 573. As illustrated in Figure 44, the edge enhancement process enhances the contour of the processed character 576 compared to the original character 575. As illustrated in Figure 45, the screen change alters the shape of the dots from the original screen 577A to the processed screen 578A. As a result, the large irregularities in the processed character 578 are less noticeable compared to the original character 577.

[0093] Due to the nature of variable printing applications, each record corresponding to individual data has an independent final destination, so it is not necessary to strictly match the image processing of the variable area across all records. For this reason, it is often acceptable to apply image processing such as thinning only to records where inspection errors occur. On the other hand, since the fixed area is common to all records, no image processing is applied to the fixed area.

[0094] Next, the inspection process flow in the fifth embodiment will be explained with reference to Figure 46. Figure 46 illustrates a process in which, for fixed areas, the correct image has already been registered, and the print job to be inspected is printed while being inspected by comparing the fixed area with the registered correct image, and for variable areas, the string read by OCR is compared with variable data. First, when the control unit 10 receives a print job consisting of image data via the communication unit 105 (step S501: Yes), it expands and analyzes the job information, page information, and image data in the print job on the memory 103 (step S502). If automatic inspection is turned on in the job information (step S503: Yes), the inspection determination unit 55 analyzes the area in the image data (step S504). If automatic inspection is turned off in the job information (step S503: No), the control unit 10 performs normal printing processing (step S591).

[0095] If the job information indicates that it is a variable print (step S505: Yes), different inspection processes are started for each area (step S506). If it is not a variable print (step S505: No), the inspection control unit 50 performs normal inspection processing (step S592). Then, the inspection and judgment unit 55, in the case of inspection of a fixed area (step S507: fixed area only), compares it with the correct image of the fixed area (step S511). If an inspection error occurs in the fixed area (step S512: Yes), the first post-inspection processing unit 51 refers to the inspection reprint information and performs reprinting (step S513), and the process in Figure 42 is completed.

[0096] In the inspection of the variable area (step S507: including the variable area), OCR processing is performed on the variable area to extract text data (step S521), and the correct image is not used; instead, it is compared with the text data of the print job (step S522). If an inspection error occurs in the variable area (step S523: Yes), the second post-inspection processing unit 52 refers to the inspection reprint information, performs a thinning process on the variable area (step S524), and then performs a reprint (step S525), and the process in Figure 46 is completed.

[0097] [Sixth Embodiment] Next, an image forming apparatus according to the sixth embodiment will be described. In the sixth embodiment, in response to inspection errors in text comparison, the text is recognized by OCR processing, and the font is changed for one of the print data in the first or second region compared with the text contained in the print data, and then reprinting is performed. The sixth embodiment differs from the fifth embodiment in that, if the characters cannot be recognized by OCR processing, the font is changed instead of image processing such as thinning and then reprinting is performed, but other aspects are the same as the fifth embodiment. Font changes involve processes such as increasing the font size or making the lines thinner, and can also involve replacing the font with a more legible type. This can improve the readability of the text.

[0098] The inspection process in the sixth embodiment is almost identical to that of the fifth embodiment, so its explanation will be omitted. In the fifth embodiment (Figure 46), step S524, in which image processing such as thinning is performed on the variable region, is replaced in the sixth embodiment (Figure 47) by step S624, in which font changes are performed.

[0099] [Control method for image forming apparatus] The control method for the image forming apparatus is a method for operating the image forming apparatus as an image forming apparatus according to the embodiment. The control method for the image forming apparatus includes the steps of: an image reading unit reading an image of a printed material and acquiring a read image; an inspection and judgment unit comparing the read image read by the image reading unit with a correct image to make an inspection judgment; a first post-inspection processing unit performing a first post-inspection processing for inspection errors in a first region of the read image; and a second post-inspection processing unit performing a second post-inspection processing different from the first post-inspection processing for inspection errors in a second region of the read image.

[0100] [Control Program] The control program is a program that is loaded into the control unit of the image forming apparatus to make the image forming apparatus function as the image forming apparatus according to the embodiment. The control program instructs the computer to execute the following procedures: read an image from a printed document and acquire the read image; compare the read image from the printed document with the correct image to determine if it is a quality check; perform a first post-inspection processing for quality check errors in the first region of the read image; and perform a second post-inspection processing, different from the first post-inspection processing, for quality check errors in the second region of the read image.

[0101] The image forming apparatus may be controlled by a computer loaded with the control program according to the embodiment. The control program according to this embodiment can be obtained via a telecommunications line and recorded on a computer-readable recording medium. [Explanation of Symbols]

[0102] 1. Image forming apparatus 10 Control Unit 11. Manuscript transport section 12 Manuscript reading unit 13 Control section 14 Image forming unit 15 Paper feeder 16 Inspection device 17 Post-processing equipment 50 Inspection Control Unit 51. Post-Inspection Processing Unit 52 Second Inspection Post-Processing Process 55 Inspection and Judgment Department 101 CPU 102 HDD 103 memory 104 Non-volatile memory 105 Communications Department 151 Paper feed section 161 Image reading unit 162 Storage section 171 Output section

Claims

1. An image reading unit that reads an image from a printed document and obtains the read image, An inspection and judgment unit compares the image read by the image reading unit with the correct image to determine whether the product is being inspected, A first post-inspection processing unit performs a first post-inspection processing on inspection errors in the first region of the read image, An image forming apparatus comprising: a second post-inspection processing unit that performs a second post-inspection processing different from the first post-inspection processing for inspection errors in a second region of the read image.

2. The image forming apparatus according to claim 1, wherein the inspection and determination unit determines the first region and the second region using different determination conditions.

3. It includes a storage unit that stores the correct image, The image forming apparatus according to claim 1, wherein the inspection and determination unit uses the read image as the correct image.

4. The image forming apparatus according to claim 3, wherein the inspection and determination unit uses the read image for the first region and the printed data for the second region as the correct image.

5. The image forming apparatus according to claim 1, wherein the first post-inspection processing unit and the second post-inspection processing unit do not reprint if the first region has an inspection error, and reprint if the second region has an inspection error.

6. The aforementioned printed material is a variable print having a variable area and a fixed area. The image forming apparatus according to claim 5, wherein the first region is the fixed region and the second region is the variable region.

7. It includes a storage unit that stores the correct image, The image forming apparatus according to claim 1, wherein the inspection and determination unit performs OCR processing on the second region to detect text and compares it with the text data contained in the second region of the correct image held in the storage unit.

8. The image forming apparatus according to claim 7, wherein the second post-inspection processing unit performs image processing on the print data in the second region in response to inspection errors in comparison with text data and then reprints.

9. The image forming apparatus according to claim 7, wherein the second post-inspection processing unit changes the font of the print data in the second region and reprints it in response to inspection errors in comparison with text data.

10. The aforementioned printed material has a spot color area and a non-spot color area, The image forming apparatus according to claim 5, wherein the first region is a feature region and the second region is a non-feature region.

11. The first region is a non-printing region, and the second region is a printing region. The first post-inspection processing unit, if the non-printing area contains an inspection error, performs reprinting including cleaning the image forming unit. The image forming apparatus according to claim 1, wherein the second post-inspection processing unit performs reprinting including color correction processing if the print area has an inspection error.

12. The image forming apparatus according to claim 1, wherein the first post-inspection processing unit and the second post-inspection processing unit can separately set an upper limit on the number of reprints in response to an inspection error.

13. The image forming apparatus according to claim 1, wherein the first post-inspection processing unit and the second post-inspection processing unit can separately set whether or not to discard subsequent paper that has already been fed in response to an inspection error, and, if so, the output unit for the destination of the discarded paper.

14. The image reading unit reads the image of the printed material and obtains the read image, The inspection and judgment unit compares the image read by the image reading unit with the correct image to make an inspection judgment, The first post-inspection processing unit performs a first post-inspection processing on inspection errors in the first region of the read image, A control method for an image forming apparatus, comprising the step of a second post-inspection processing unit performing a second post-inspection processing unit, different from the first post-inspection processing unit, on an inspection error in a second region of the read image.

15. On the computer, Procedure for reading an image from a printed document and obtaining the scanned image. A procedure for determining quality by comparing the image read from the aforementioned printed material with the correct image, A procedure for performing a first post-inspection processing on inspection errors in the first region of the read image, A procedure for performing a second post-inspection process, different from the first post-inspection process, for inspection errors in the second region of the read image, A control program to execute the program.

Images