Image inspection device, image inspection method, and image inspection program

Abstract

To provide an image inspection device, an image inspection method, and an image inspection program with which it is possible to detect an image defect even when the image defect is not only in a non-variable area but also in a variable area.SOLUTION: An image inspection device 300 has an image forming unit 330, a reference image creation unit 380, and an image inspection unit 350. The image forming unit 330 forms an image on a recording medium on the basis of image data. The reference image creation unit 380 creates a reference image used for inspection of the image formed on the recording medium on the basis of the image data. The image inspection unit 350 conducts inspection of the image formed on the recording medium on the basis of the reference image. The reference image creation unit 380 creates the reference image to be compared with a read image for which the image inspection unit 350 conducts inspection, for images on a page including a non-variable area in which the image forming unit 330 forms the same image on a plurality of pages and a variable area in which the image forming unit forms different images on respective pages.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image inspection device, an image inspection method, and an image inspection program. [Background technology]

[0002] Variable printing, which prints an original image that includes variable and non-variable areas, has been known for some time, for example when sending direct mail with the same content to multiple recipients. A variable area is an area in an original image where the image changes (is different) from page to page, such as the destination, while a non-variable area is an area in an original image where the image is the same on all pages, such as the content.

[0003] However, in the case of direct mail and other mail sent to multiple recipients, the quality of a large volume of printed paper (printed matter) must be inspected before shipping. While inspection requires the prior registration of a reference image, registering reference images for all pages in advance is time-consuming in order to inspect variable areas where the image varies from page to page. For example, Patent Document 1 below discloses that a user inspects several printed matter with printed inspection images and registers the scanned image of a printed matter that is determined to be normal as a reference image. When only one copy of a printed matter with the same content is produced, such as direct mail, it is not practical to register reference images for all pages in advance. Conventionally, to shorten the inspection time, a method has been used in which the non-variable area is set as the inspection area and the variable area is set as the inspection exclusion area, and only the non-variable area of ​​the printed matter is inspected, omitting inspection of the variable area of ​​the printed matter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-146514 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when inspection of the variable area of ​​the printed matter is omitted, there is a problem in that if there is an image defect such as a stain in the variable area, the image defect cannot be detected.

[0006] The present invention has been made in view of the above circumstances, and aims to provide an image inspection device, an image inspection method, and an image inspection program that can detect image defects not only in non-variable areas but also in variable areas. [Means for solving the problem]

[0007] The above object of the present invention can be achieved by the following means.

[0008] (1) An image inspection device comprising: an image forming unit that forms an image on a recording medium based on image data; a reference image generating unit that generates a reference image to be used in inspecting the image formed on the recording medium based on the image data; and an image inspection unit that inspects the image formed on the recording medium based on the reference image, wherein the reference image generating unit generates a reference image for comparing with a read image inspected by the image inspection unit for an image of a page that includes a non-variable area in which the same image is formed on multiple pages by the image forming unit and a variable area in which a different image is formed on each page.

[0009] (2) The image inspection device according to (1), wherein the reference image generating unit generates the reference image for each page.

[0010] (3) The image inspection device according to (1) or (2) above, wherein the image inspection unit performs the same type of inspection on variable and non-variable areas included in the image.

[0011] (4) An image inspection device as described in (1) or (2) above, further comprising a control unit that controls the execution of a first inspection mode in which the image inspection unit performs inspection on the variable area, and the execution of a second inspection mode in which the image inspection unit does not perform inspection, wherein the control unit causes the reference image generation unit to generate the reference image for the image of the non-variable area, and when executing the first inspection mode, causes the reference image generation unit to generate the reference image for the image of the variable area, and when executing the second inspection mode, does not cause the reference image generation unit to generate the reference image for the image of the variable area.

[0012] (5) An image inspection device as described in (1) or (2) above, further comprising a matching unit that compares the image-formed information with the information obtained from the read image for the variable area, and performs inspection of the variable area by the image inspection unit and matching by the matching unit.

[0013] (6) The image inspection device according to (5) above, wherein the inspection process by the image inspection unit and the collation process by the collation unit are carried out in parallel in the variable region.

[0015] ( 7 ) An image inspection method comprising the steps of: (a) forming an image on a recording medium based on image data; (b) generating a reference image to be used for inspecting the image formed on the recording medium based on the image data; and (c) inspecting the image formed on the recording medium based on the reference image, wherein in step (b), a reference image is generated for an image of a page that includes non-variable areas in which the same image is formed on multiple pages by step (a) and variable areas in which different images are formed on each page by step (c) to be compared with the read image to be inspected. (8) The image inspection method according to (7) above, wherein in step (b), the reference image is generated for each page. (9) The image inspection method according to (7) or (8) above, wherein in step (c), the same type of inspection is performed on variable and non-variable areas included in the image. (10) An image inspection method as described in (7) or (8) above, further comprising a step (d) of controlling the execution of a first inspection mode in which inspection is performed in step (c) for the variable region and the execution of a second inspection mode in which inspection is not performed in step (c), wherein the control in step (d) causes the reference image to be generated for the image of the non-variable region in step (b), and when the first inspection mode is executed, the reference image is generated for the image of the variable region in step (b), and when the second inspection mode is executed, the reference image is not generated for the image of the variable region in step (b). (11) An image inspection method as described in (7) or (8) above, further comprising a step (e) of comparing the image-formed information of the variable area with the information obtained from the read image, and performing inspection in step (c) and matching in step (e) for the variable area. (12) The image inspection method according to (11) above, wherein the inspection process in step (c) and the matching process in step (e) are carried out in parallel for the variable region.

[0016] ( 13 ) An image inspection program for causing a computer to execute a process comprising: a step (a) of forming an image on a recording medium based on image data; a step (b) of generating a reference image to be used in inspecting the image formed on the recording medium based on the image data; and a step (c) of inspecting the image formed on the recording medium based on the reference image, wherein in step (b), a reference image is generated for comparison with a read image to be inspected in step (c) for an image of a page that includes a non-variable area in which the same image is formed on multiple pages by step (a) and a variable area in which a different image is formed for each page. (14) The image inspection program according to (13) above, wherein in the step (b), the reference image is generated for each page. (15) The image inspection program according to (13) or (14) above, wherein in the step (c), the same type of inspection is performed on variable areas and non-variable areas included in the image. (16) An image inspection program as described in (13) or (14) above, further comprising a step (d) of controlling the execution of a first inspection mode in which inspection is performed in step (c) for the variable area, and the execution of a second inspection mode in which inspection is not performed in step (c), wherein the control in step (d) causes the reference image to be generated for the image of the non-variable area in step (b), and when the first inspection mode is executed, the reference image is generated for the image of the variable area in step (b), and when the second inspection mode is executed, the reference image is not generated for the image of the variable area in step (b). (17) The method further includes a step (e) of comparing the image-formed information with the information obtained from the read image for the variable area, The image inspection program according to (13) or (14) above, which performs the inspection in the step (c) and the matching in the step (e) for the variable region. (18) The image inspection program according to (17) above, which performs the inspection process in step (c) and the matching process in step (e) in parallel for the variable region. [Effects of the Invention]

[0017] According to the present invention, a reference image is generated for a page image including a variable area and a non-variable area to be compared with a scanned image to be inspected, so that inspection can be performed not only on the non-variable area but also on the variable area. Therefore, image defects can be detected not only in the non-variable area but also in the variable area. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic block diagram of a printing system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic block diagram illustrating the configuration of the image forming system shown in FIG. [Figure 3] FIG. 2 is a schematic diagram illustrating an example of an original image including a variable area and a non-variable area. [Figure 4]10A and 10B are schematic diagrams illustrating a scanned image including a barcode image in a variable area. [Figure 5] 3 is a block diagram for explaining an outline of the control operations of the control unit and the print controller unit shown in FIG. 2. FIG. [Figure 6] 2 is a flowchart illustrating a processing procedure of an image inspection method performed by the image forming system shown in FIG. 1. [Figure 7] FIG. 2 is a schematic diagram showing the time series of processes of acquiring an original image, generating a reference image, forming an inspection image, inspecting the inspection image, and comparing the inspection image. [Figure 8] 1A to 1C are schematic diagrams showing the printing of a plurality of copies of an original image in time series. [Figure 9] 7 is a subroutine flowchart illustrating details of the processing procedure for generating a reference image (S103) in the flowchart shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation, and may differ from the actual proportions.

[0020] (Embodiment) <Printing system configuration> FIG. 1 is a schematic block diagram of a printing system according to a first embodiment of the present invention, and FIG. 2 is a schematic block diagram illustrating the configuration of the image forming system shown in FIG.

[0021] 1, the printing system 100 includes a client terminal 200 and an image forming system 300. The client terminal 200 and the image forming system 300 are connected to each other via a communication line 400 so that they can communicate with each other.

[0022] The client terminal 200 may be, for example, a personal computer, a tablet terminal, a smartphone, or the like. A printer driver for converting manuscript data into a print job is installed in the client terminal 200. The printer driver generates a print job in a format compatible with the print controller unit 320 (see FIG. 2) of the image forming system 300, and transmits the print job to the image forming system 300 via a communication line 400. The client terminal 200 also has a display that can display the inspection results of the printed matter (good / defective), images of defective printed matter, etc.

[0023] The print job includes, for example, print data in PDL (Page Description Language) format and job information. In this embodiment, the print job may include a variable print job for performing variable printing. Variable printing refers to printing in which the print content of each sheet can be partially replaced as needed. The print data includes, for example, data for one or more copies consisting of pages 1 to n. The job information includes print settings such as the number of pages, the number of copies, paper (recording medium) type, size, basis weight, single-sided printing / double-sided printing, variable printing information, inspection mode, inspection setting (on / off), collation setting (on / off), and information regarding the inspection exclusion area. The variable printing information includes information regarding the presence or absence of variable printing, the positions of the variable and non-variable areas, etc. The user can issue an image inspection instruction to the image forming system 300 by turning on the inspection setting. The user can also issue a collation instruction to the image forming system 300 by turning on the collation setting. The information about the inspection exclusion region is information about designation of an inspection region where inspection is performed by the image inspection unit 350 and / or designation of an inspection exclusion region where inspection is not performed.

[0024] The communication line 400 may be a LAN (Local Area Network) that connects computers or network devices together according to a predetermined standard, or a WAN (Wide Area Network) that connects LANs together via a dedicated line, etc. Examples of predetermined standards include Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), and Wi-Fi (Wireless Fidelity).

[0025] The number of the above components connected to the communication line 400 is not limited to the example shown in FIG.

[0026] <Inspection mode> The image forming system 300 of this embodiment has inspection modes including a first inspection mode and a second inspection mode. In the first inspection mode, reference images of the variable and non-variable areas are generated, and the variable areas are inspected in addition to the non-variable areas. More specifically, when printing multiple copies, reference images are generated for all pages in all copies, making it possible to inspect both the variable and non-variable areas. In the second inspection mode, the user sets the non-variable areas as inspection areas and the variable areas as areas excluded from inspection, and inspection is performed on the non-variable areas, but not on the variable areas. In this embodiment, the original image includes images of multiple pages, and each page may include both variable and non-variable areas. A variable area is an area where the image changes (is different) from page to page, such as the address in a direct mail message, while a non-variable area is an area where the image is the same on all pages, such as the content of the original image.

[0027] In this embodiment, the inspection mode may be set to the first inspection mode by default. The user can change the inspection mode as needed. The first inspection mode is suitable for print jobs that include variable printing. When the first inspection mode is executed, a reference image is generated for the image in the variable area, while when the second inspection mode is executed, a reference image is not generated for the image in the variable area. Regardless of the inspection mode, a reference image is generated for the non-variable area. Information regarding the inspection mode is stored in the control unit 310 of the image forming system 300, which will be described below.

[0028] <Configuration of Image Forming System 300> 1 and 2, the image forming system 300 includes a control unit 310, a print controller unit 320, an image forming unit 330, an image reading unit 340, an image inspection unit 350, a collation unit 355, an operation display unit 360, a paper feed unit 370, a reference image generation unit 380, and a storage device 390. The image forming system 300 functions as an image inspection device.

[0029] <Configuration of control unit 310> The control unit 310 includes an image control CPU (Central Processing Unit) 311, a DRAM (Dynamic Random Access Memory) control IC 312, a memory 313, an image memory (DRAM) 314, a compression / decompression IC 315, a read processing unit 316, a write processing unit 317, a memory unit 318, etc.

[0030] Image control CPU 311 loads various programs stored in storage unit 318 into memory 313, and controls the overall operation of image forming system 300 in cooperation with the loaded programs.

[0031] The reading processing unit 316 performs various processes, such as analog processing, A / D conversion processing, and shading processing, on the analog image signal output from the scanner 341 of the image reading unit 340 to generate digital image (read image) data. The generated digital image data is output to the compression / decompression IC 315 by the DRAM control IC 312. The compression / decompression IC 315 performs compression processing on the digital image data and decompression processing on the compressed digital image data under the control of the DRAM control IC 312. The DRAM control IC 312 also controls input / output to and from the image memory (DRAM) 314 for the compressed / decompressed digital image data.

[0032] The image memory 314 is made up of DRAM and has an internal compression memory and page memory area, and temporarily stores compressed image data, decompressed image data, and the like.

[0033] The write processing unit 317 outputs the decompressed digital image data to an exposure unit 332 of the image forming unit 330 .

[0034] <Configuration of print controller unit 320> The print controller unit 320 analyzes the print job received from the client terminal 200 via the communication line 400, and performs processes such as color conversion, screening, and rasterization to generate an original image in bitmap format. The generated original image is sent to the control unit 310. The print controller unit 320 functions as an original image acquisition unit.

[0035] FIG. 3 is a schematic diagram illustrating an example of an original image including a variable area and a non-variable area. The original image in FIG. 3 includes, for example, multiple copies (three copies) of one-page images (DI1 to DI3), and each page of each copy includes a variable area (VA1 to VA3) and a non-variable area (NV1 to NV3). The images ("A," "B," and "C") in the variable area of ​​the original image are different for each copy. On the other hand, the images in the areas of the original image other than the variable area, i.e., the non-variable areas (NV1 to NV3), are the same (common) for each copy of the original image. For example, when printing three copies of a 10-page original, the image in the non-variable area of ​​the first page is common to all three copies. On the other hand, pages 1 to 10 often have different images in their non-variable areas. In other words, the original image is composed of the same image in the non-variable area for the same page (e.g., page 1) in each copy, but different images in the variable area for each copy.

[0036] When each copy consists of multiple pages, all pages may contain variable areas, or only some pages may contain variable areas. For example, only the first page (cover) of each copy may contain a variable area, and the second and subsequent pages may not contain a variable area and may consist of only non-variable areas.

[0037] The print controller unit 320 is configured with a controller control unit 321, a reference image generation control unit 322, a DRAM control IC 323, an image memory (DRAM) 324, a communication control unit 325, a communication I / F 326, etc. The controller control unit 321 comprehensively controls the operation of each unit of the print controller unit 320. The controller control unit 321 also receives print jobs from the client terminal 200, etc. via the communication I / F 326. The communication control unit 325 controls the communication I / F 326.

[0038] The received print job includes print data (mainly in PDL format) that is the source of the original image, and job information that describes print settings such as the type of paper to be used. The print controller unit 320 performs rasterization (RIP) processing, which converts the print data into bitmap data on a page-by-page basis based on the print settings. The RIP image after rasterization is temporarily stored in image memory 324. The RIP image in image memory 324 is temporarily stored in a compressed memory area within image memory 314 via compression / decompression IC 315 under the control of DRAM control IC 323 of print controller unit 320 and DRAM control IC 312 of control unit 310. During normal printing, the RIP image stored in the compressed memory area is decompressed by compression / decompression IC 315 and sent as an original image (image data) to image forming unit 330 via write processing unit 317, where it is printed.

[0039] The reference image generation control unit 322 outputs a reference image generation instruction to the reference image generation unit 380 (described later) to generate a reference image based on the document image at a predetermined generation timing. The predetermined generation timing may be, for example, when the inspection setting is on and the document image acquisition unit acquires the document image. The reference image generation unit 380 generates a reference image based on the reference image generation instruction.

[0040] Ideally, a scanned image generated by scanning an inspection image formed on paper would match the original image in terms of content. However, when scanning an inspection image formed on paper using a scanner, errors can occur in the scanned image compared to the original image due to various factors, such as variations in the paper transport path, misalignment of the scanner's reading position, color reproducibility, and differences in paper type. Furthermore, errors can also occur in the scanned image compared to the original image depending on the resolution of the scanner. Therefore, simply comparing the scanned image with the original image is likely to result in errors, and it is not realistic to inspect the inspection image by simply comparing the scanned image with the original image. Therefore, in this embodiment, various processes are performed on the original image regarding position, resolution, color, etc. to generate a reference image that can be compared with the scanned image, and the scanned image is then compared with the reference image. This allows for appropriate comparison with the scanned image, enabling accurate inspection of printed materials. Details of the reference image generation process will be described later. Although FIG. 2 illustrates an example in which the reference image generation control unit 322 is provided in the print controller unit 320, the reference image generation control unit 322 may be configured to be provided in the control unit 310.

[0041] <Configuration of Image Forming Unit 330> The image forming unit 330 forms (prints) an image on paper using an electrophotographic method including the processes of charging, exposing, developing, transferring, and fixing, in accordance with instructions from the control unit 310. In this embodiment, the image forming unit 330 forms an inspection image on paper under image formation conditions set based on the print settings, to be inspected by the image inspection unit 350. When the inspection image is formed using variable printing, the image formed on the paper may include a non-variable area where the same image is formed on multiple pages, and a variable area where a different image is formed on each page.

[0042] The image forming unit 330 includes a printer control unit 331 and an exposure unit 332. The printer control unit 331 is connected to the image control CPU 311 via serial communication and receives control from the image control CPU 311. The printer control unit 331 drives an LD (laser diode) of the exposure unit 332 in response to a signal from the writing processing unit 317, causing an electrostatic latent image corresponding to the document image to be formed on a photosensitive member (not shown). The toner image formed on the photosensitive member is developed through a developing process and transferred onto paper supplied from the paper feed unit 370. The unfixed toner image on the paper is then fixed by applying heat and pressure. The paper on which the toner image has been fixed is transported to the image reading unit 340.

[0043] The image forming unit 330 also includes a print sheet discharge device that separates and discharges (purges) paper (waste paper) on which an inspection image that has been detected as defective by the image inspection unit 350 has been formed from paper on which a good inspection image has been formed.

[0044] <Configuration of image reading unit 340> The image reading unit 340 has a scanner 341 and a scanner control unit 342. The scanner 341 reads the paper (printed material) being transported along the transport path, for example, using a CCD (Charge Coupled Device) image sensor. The scanner control unit 342 controls the scanner to read the inspection image formed on the paper transported from the image forming unit 330 in accordance with a reading instruction from the control unit 310. The scanner control unit 342 outputs the read image obtained by reading the inspection image formed on the paper to the control unit 310.

[0045] <Configuration of image inspection unit 350> The image inspection unit 350 performs image inspection based on the reference image. The image inspection unit 350 has an image inspection control unit 351. The image inspection control unit 351 has a CPU, RAM, ROM, and auxiliary storage device (not shown). The function of inspecting the inspection image is realized by the CPU executing an image inspection program.

[0046] In this embodiment, the image inspection control unit 351 acquires information about the inspection mode from the control unit 310 and inspects the inspection image according to the inspection mode. When the inspection mode is the first inspection mode, the image inspection control unit 351 generates reference images for all pages, including variable areas, so that the user does not need to set variable areas, whose content varies from page to page, as inspection exclusion areas. Therefore, by setting variable areas and non-variable areas as inspection areas, the inspection image is inspected for all areas, including variable areas, on the page. On the other hand, when the inspection mode is the second inspection mode, the user sets non-variable areas as inspection areas and variable areas as inspection exclusion areas on the page. As a result, the inspection image is not inspected for variable areas on the page. Regardless of whether the inspection mode is the first or second inspection mode, the image inspection control unit 351 inspects areas of the page that do not contain variable areas, i.e., non-variable areas, on the inspection image.

[0047] The image inspection unit 350 acquires a reference image, a scanned image, and variable print information, and compares the reference image and scanned image for each page for both the variable and non-variable areas to inspect the inspection image formed on the paper. In the first inspection mode of this embodiment, the same type of inspection is performed on the variable areas as on the non-variable areas. Image defects detected by the inspection can include, for example, streak-like defects (streaks) and spot-like defects (fireflies). Streaks are defects caused by scratches or dirt on components such as the drum or roller of the image forming device or the scanning surface of the scanner, and can appear as differences in pixel value gradation or density unevenness not included in the original image. Examples of streaks include white streaks that are lighter than the original image and black streaks that are darker than the original image. Fireflies are spot-like image defects not present in the original image data and are easily noticeable to the user, especially in printed halftone images.

[0048] As a relatively simple method for detecting image defects, the image inspection control unit 351 calculates the difference (error) in pixel values ​​between the reference image and the scanned image for each page, and determines whether the inspection image is good or bad depending on the magnitude of the difference. The calculation of the difference can be performed for each page, each object, or each region. For example, when calculating the difference for each page, if the total value of the pixel differences within a page is less than a specified value, an inspection result of "good" is output, and if the total value of the differences is equal to or greater than the specified value, an inspection result of "bad" is output. Furthermore, when calculating the difference for each object or region, the system can be configured to output an inspection result of "good" or "bad" depending on the total value of the pixel differences within the selected object or region.

[0049] If the inspection result of the inspection image is "good", the control unit 310 determines that the printed matter is a good product, and if the inspection result of the inspection image is "bad", the control unit 310 determines that the printed matter is a defective product.

[0050] <Configuration of the collation unit 355> FIG. 4 is a schematic diagram illustrating a scanned image including a barcode image in a variable area. The collation unit 355 collates the test image based on information included in the variable area of ​​the scanned image. That is, the collation unit 355 determines whether the information included in the variable area of ​​the scanned image matches pre-registered information, thereby determining whether the test image is correct. The information included in the variable area is information image-formed in the variable area by the image forming unit 330. The image-formed information is, for example, an identifier such as a barcode or QR code (registered trademark), and may differ for each page. For example, as shown in FIG. 4, the variable areas (VA4 to VA6) of pages 1 to 3 of the scanned image include different barcodes as image-formed information. For example, pre-registered original information (referred to as first text information) is coded using a barcode or QR code and printed in the variable area. The collation unit 355 then compares information (second text information) obtained by decoding the scanned image of the variable area with the first text information. In the verification process, the text information obtained by OCR processing may be compared without decoding. For example, as shown in the example of Fig. 3, the text information printed in the variable area (first text information such as the letters A, B, and C) is verified with the second text information obtained by OCR processing of the scanned image.

[0051] The collation unit 355 has a collation control unit 356. The collation control unit 356 has a CPU, RAM, ROM, and auxiliary storage device (not shown). The function of collation of the inspection image is realized by the CPU executing an image inspection program. In response to instructions from the control unit 310, the collation control unit 356 acquires a scanned image from the image reading unit 340 and decodes the image in the variable area of ​​each page (SI1 to SI3) of the scanned image to convert it into numerical data. The collation unit 355 compares the converted numerical data for each page with information (registered information) registered in advance for each page and transmits the collation result to the control unit 310. The registered information is linked to the document image and stored in advance in the memory unit 318 of the control unit 310 or in a memory unit provided in the collation unit 355.

[0052] <Configuration of operation display unit 360> The operation display unit 360 includes a touch screen 361, an operation control unit 362, a numeric keypad as hard keys, a start button, a stop button, and the like. The touch screen includes, for example, a touch sensor and an LCD (Liquid Crystal Display) located behind the touch sensor. The operation control unit 362 accepts input from the touch sensor and hard keys and transmits the input data to the control unit 310. The operation control unit 362 also receives output data from the control unit 310 and displays it on the LCD. The operation display unit 360 is used by the user to input various settings (e.g., turning the inspection setting on / off, changing the inspection mode, turning the verification setting on / off) and instructions (e.g., an instruction to start printing). The operation display unit 360 is also used to output (display) the status of the image forming system 300, the inspection results of printed materials (good / bad), the verification results (good / bad), images of defective printed materials, etc.

[0053] <Configuration of Paper Feed Unit 370> The paper feed unit 370 includes at least one large-capacity paper tray, and supplies paper to the image forming unit 330 one sheet at a time.

[0054] <Configuration of Reference Image Generator 380> The reference image generating unit 380 generates a reference image based on the document image acquired by the document image acquiring unit and outputs the generated reference image to the control unit 310. More specifically, the reference image generating unit 380 generates a reference image for comparing with the scanned image inspected by the image inspecting unit 350 for an image of a page including a variable area and a non-variable area. The reference image generating unit 380 acquires information related to the inspection mode from the control unit 310. The reference image generating unit 380 generates a reference image for each page based on the document image in accordance with the inspection mode.

[0055] More specifically, when the first inspection mode is executed as the inspection mode, the reference image generation unit 380 generates reference images for each page for both the variable area and the non-variable area of ​​the document image. On the other hand, when the second inspection mode is executed, the reference image generation unit 380 generates reference images only for the non-variable area set as the inspection target area of ​​the document image. In this case, a reference image is not generated for the variable area set as the inspection excluded area. In the second inspection mode, reference images are not generated for all pages of the document, so accurate inspection of the variable area is not possible. Therefore, inspection is not performed for the variable area set as the inspection excluded area (see FIG. 9). Note that here, reference images may also be generated for the image of the variable area in the second inspection mode, and the variable area may be set as the inspection excluded area by masking it in a subsequent inspection mode.

[0056] The reference image generation unit 380 can be realized by a CPU (not shown) separate from the image control CPU 311 executing an image inspection program. This allows the generation of the reference image and the formation and inspection of the inspection image to be performed in parallel. Alternatively, if the image control CPU 311 is a multi-core CPU, the reference image generation unit 380 may be assigned to a core separate from the processing of the inspection image formation and inspection, and the generation of the reference image and the formation and inspection of the inspection image may be performed in parallel by the separate cores.

[0057] In the past, the same CPU was configured to generate the reference image and form and inspect the inspection image. Therefore, the CPU would form and inspect the inspection image after completing the generation of the reference image for each page, so it was not possible to generate the reference image and form and inspect the inspection image in parallel. In this embodiment, the generation of the reference image and the formation and inspection of the inspection image are configured to be performed by separate CPUs, so the generation of the reference image and the formation and inspection of the inspection image can be performed in parallel.

[0058] Furthermore, if the original image is a complex image, the computational load for generating the reference image may increase significantly. By having a CPU other than image control CPU 311 take charge of generating the reference image, the computational load on image control CPU 311 can be reduced.

[0059] <Configuration of storage device 390> The storage device 390 stores the reference image generated by the reference image generating unit 380. When reprinting an original image, the control unit 310 uses the reference image stored in the storage device 390, eliminating the need to generate the reference image again. This eliminates the need to generate the reference image again.

[0060] <Outline of Control Operations of Control Unit 310 and Print Controller Unit 320> FIG. 5 is a block diagram for explaining an outline of the control operations of the control unit 310 and the print controller unit 320 shown in FIG.

[0061] First, the control unit 310 receives an original image and job information from the original image acquisition unit (print controller unit 320) ((1) Image input). The original image is an RIP image obtained by rasterizing print data.

[0062] When reference image generation unit 380 receives a reference image generation instruction from reference image generation control unit 322 ((2)-1 reference image generation instruction), it generates a reference image based on the document image acquired by the document image acquisition unit and outputs it to control unit 310. Control unit 310 saves the reference image in page memory 1. As described above, when the inspection mode is the first inspection mode, reference image generation unit 380 generates reference images for both variable and non-variable areas based on the document image. When the inspection mode is the second inspection mode, inspection of the variable area is not performed, so reference image generation unit 380 does not generate a reference image for the variable area, but generates a reference image consisting of only the non-variable area.

[0063] The reference image generation unit 380 generates a reference image by performing various processes on the original image regarding position, resolution, color, etc. For example, the reference image generation unit 380 can extract position information of content portions from the original image and add or embed the position information in the reference image so that the content portions (contents) of the reference image and the scanned image can be compared. That is, the reference image generated by the reference image generation unit 380 contains alignment information for aligning the reference image and the scanned image when performing image inspection based on the reference image. The alignment information includes image contour information and edge information. The reference image generated by the reference image generation unit 380 also contains area information regarding the inspection area and the non-inspection area used when performing image inspection based on the reference image. Furthermore, the reference image generation unit 380 can generate a reference image by adjusting the resolution of the original image to match the resolution of the scanner of the image reading unit 340. Furthermore, the reference image generating unit 380 can generate a reference image by converting the color space of the original image so that it matches the color space (for example, RGB) used by the scanner of the image reading unit 340 .

[0064] Furthermore, when the control unit 310 receives an original image from the original image acquisition unit, it instructs the image forming unit 330 to form an image and outputs the original image stored in the page memory 1 to the image forming unit 330 ((2)-2 image output). In this embodiment, the image forming unit 330 forms an inspection image on paper based on the original image. When the inspection mode is the first inspection mode, the generation of the reference image by the reference image generation unit 380 and the formation of the inspection image by the image forming unit 330 are executed in parallel.

[0065] When the reference image generation unit 380 completes the generation of the reference image, it notifies the control unit 310 and the reference image generation control unit 322 of the completion of the reference image generation ((3)-1 Reference image generation completed). Furthermore, when the image forming unit 330 completes the image formation on the paper, it notifies the control unit 310 of the completion of output ((3)-2 Output completed). The storage device 390 saves the generated reference image ((4)-1 Save reference image).

[0066] Furthermore, upon receiving notification of output completion, the control unit 310 immediately outputs an image reading instruction to the image reading unit 340 ((4)-2 Image reading instruction). The image reading unit 340 reads the paper on which the inspection image is formed, and outputs the read image of the paper to the control unit 310. The control unit 310 stores the read image in the page memory 2. Upon completion of reading the paper, the image reading unit 340 notifies the completion of image reading ((5)-2 Image reading completion).

[0067] When the inspection setting is on, the control unit 310 receives a notification that image reading is complete and outputs an image inspection instruction to the image inspection unit 350 ((6)-2 Image inspection instruction). The image inspection unit 350 obtains a reference image and a read image from page memory 1 and page memory 2, respectively, and inspects the inspection image by comparing the reference image with the read image. The image inspection unit 350 then outputs the inspection results of the inspection image to the control unit 310 ((7)-2 Image inspection results).

[0068] Furthermore, when the collation setting is on, the control unit 310 receives a notification that image reading is complete and outputs a collation instruction to the collation unit 355 ((8)-2 Collation Instruction). The collation unit 355 acquires the read image from the page memory 2 and decodes the image-formed information (e.g., the barcode image in FIG. 4) in the variable area of ​​the read image to convert it into numerical data. The collation unit 355 then compares the converted numerical data with the registered information of each page to collate the test image. The collation unit 355 then outputs the collation result of the image-formed information to the control unit 310 ((9)-2 Collation Result).

[0069] In response to an instruction from the user, the control unit 310 controls the display of the operation and display unit 360 or the client terminal 200 to display the inspection result (good / bad) of the printed matter based on the inspection result of the inspection image. In addition, in response to an instruction from the user, the control unit 310 controls the display of the operation and display unit 360 or the client terminal 200 to display the comparison result of the inspection image.

[0070] <Image Inspection Method Using Image Forming System 300> Fig. 6 is a flowchart illustrating the processing procedure of an image inspection method by the image forming system shown in Fig. 1. Each process shown in Fig. 6 is realized by image control CPU 311 executing an image inspection program. Fig. 7 is a schematic diagram showing, in chronological order, each process of acquiring an original image, generating a reference image, forming an inspection image, inspecting the inspection image, and comparing the inspection image. Fig. 8 is a schematic diagram showing, in chronological order, the printing of multiple copies of an original image.

[0071] As shown in FIG. 6, first, the control unit 310 acquires an original image (step S101). The original image may consist of one or more copies, and each copy may include one or more pages. When the original image consists of multiple copies, the control unit 310 receives the original image (RIP image) from the original image acquisition unit one page at a time, from the first page to the final mth page, for each copy, starting with the first copy and ending with the final Nth copy. For example, FIG. 7 illustrates a case where the original image consists of multiple copies and the first page to the eighth page of the nth copy are received in order. Note that in FIG. 7, "1P" represents the first page (similarly for "2P," etc.). Furthermore, "print preparation" in forming the test image includes initial settings and preparations (e.g., warming up the fixing unit) of each unit in accordance with the image formation conditions in the image forming unit 330.

[0072] Next, the control unit 310 stores the document images (step S102). When a print job is started, the control unit 310 stores the document images acquired from the document image acquisition unit in the page memory 1 page by page.

[0073] Next, when the inspection mode is the first inspection mode, the reference image generation control unit 322 controls the reference image generation unit 380 to generate a reference image to be used in inspecting the inspection image. The reference image generation unit 380 generates a reference image in accordance with an instruction from the reference image generation control unit 322 (step S103). For example, when the first page of the original image is acquired and stored in the page memory 1, the reference image generation control unit 322 controls the reference image generation unit 380 to generate a reference image based on the first page of the original image. The reference image generation unit 380 generates a reference image based on the first page of the original image. A reference image is similarly generated for the second page of the original image.

[0074] In this embodiment, when the inspection mode is the first inspection mode, the control unit 310 controls the image forming unit 330 to form an inspection image on paper based on the original image and job information received from the original image acquisition unit, in parallel with the generation and storage of the reference image (steps S103 and S104). Also, when the inspection mode is the second inspection mode, it is not necessary to generate and store the reference image and form the inspection image in parallel; the reference image may be generated in advance, and then the inspection image may be formed. Details of the processing procedure for generating the reference image will be described later.

[0075] Next, the storage device 390 stores the reference image generated by the reference image generation unit 380 (step S104). For example, the storage device 390 stores reference images of the first and second pages of the document image. For example, when the inspection mode is the first inspection mode, the control unit 310 performs print preparation and controls the image forming unit 330 to form an inspection image on paper for the first page of the document image. The image forming unit 330 forms an inspection image on paper for the first page of the document image in accordance with the instructions of the control unit 310 (step S105). After the inspection image for the first page of the document image is formed, an inspection image for the second page of the document image is similarly formed on paper. When the inspection image is formed using variable printing, the image formed on paper may include a non-variable area where the same image is formed on multiple pages and a variable area where a different image is formed on each page. For example, multiple copies of the same page (e.g., the first page) may include a non-variable area where the same image is formed and a variable area where different images are formed between copies.

[0076] Next, the image reading unit 340 reads the test image formed on the paper (step S106).

[0077] Next, the reference image determination unit determines whether a reference image has been generated for each page of the acquired document image (step S107). That is, after reading the image formed on the paper based on the test image, the reference image determination unit determines whether a reference image corresponding to the test image has been generated. If a reference image has been generated (step S107: YES), the control unit 310 controls the image inspection unit 350 to compare the reference image with the read image to inspect the test image. The image inspection unit 350 inspects the test image in accordance with the instructions of the control unit 310 (step S108). Furthermore, if a reference image has been generated (step S107: YES), the control unit 310 controls the matching unit 355 to match the test image in parallel with the inspection of the test image. The matching unit 355 matches the test image in accordance with the instructions of the control unit 310 (step S109). The matching unit 355 performs matching by comparing information on the image formed with information obtained from the read image for the variable region. The process of matching the test images is also referred to as a matching process. The inspection image may be collated after or before the inspection of the inspection image is completed.

[0078] Then, the control unit 310 repeats the processes of steps S101 to S109 until inspection of the inspection images for all pages (from the first page to the final n-th page) is completed (step S110).

[0079] Furthermore, control unit 310 repeats printing until the number of copies set in the job information is reached (step S111). As shown in Fig. 8, in this embodiment, when the set number of copies is N, for example, reference image generation unit 380 generates a reference image N times until printing is completed. That is, reference image generation unit 380 performs processing to generate a reference image for each copy, even for the same page, thereby generating a reference image for each copy to be used for inspecting the inspection images formed on each of the multiple copies of paper by image forming unit 330.

[0080] As described above, in this embodiment, the control unit 310 can control the generation of a reference image and the formation of an inspection image to be performed in parallel. When multiple copies are to be printed, the control unit 310 can control the generation of a reference image and the formation of an image on paper to be performed in parallel for each copy. For example, the control unit 310 controls the generation of a reference image and the formation of an inspection image to be performed in parallel for the first copy of the multiple copies.

[0081] Furthermore, the process of generating a reference image is referred to as a reference image generating process, and the process including forming an inspection image on paper and inspecting the scanned image generated by scanning the paper on which the inspection image has been formed is referred to as an inspection process. The control unit 310 can control the reference image generating process and the inspection process to be performed in parallel for the nth copy of the multiple copies. For example, the control unit 310 controls the reference image generating process and the inspection process to be performed in parallel for the first copy of the multiple copies.

[0082] Furthermore, the control unit 310 can control the generation of a reference image for the (n+1)th copy of the multiple copies to be performed in parallel with the inspection of the nth copy of paper. For example, the control unit 310 controls the generation of a reference image for the second copy of the multiple copies to be performed in parallel with the inspection of the first copy of paper.

[0083] On the other hand, if the reference image has not been generated (step S107: NO), the image inspection unit 350 waits until the reference image is generated. For example, if the reference image of the same document image (first page) as the document image (first page) that is the basis of the inspection image inspected in step S108 has not been generated, the image inspection unit 350 waits until the reference image of this document image (first page) is generated.

[0084] 7, the generation of the reference image by reference image generation unit 380, the formation of the test image, the inspection of the test image, and the comparison of the test image are performed in parallel. This allows image forming system 300 to further reduce the time required for the processes from the generation of the reference image to the inspection and comparison of the test image compared to conventional techniques.

[0085] [Parallel generation of reference image and formation of test image on paper] For example, in the example shown in FIG. 7, the generation of reference images for the first page (1P) and the second page (2P) and the preparation for printing are performed in parallel, and the generation of reference images for the third page (3P) and the fourth page (4P) and the formation of the inspection image (first half) for the first page (1P) are performed in parallel. Note that while the figure shows the generation of the reference image for the third page (3P) and the formation of the inspection image for the first page (1P) starting simultaneously, this is not a limitation. The formation of the inspection image for the first page (1P) can start at an appropriate time after the completion of the preparation for printing, and the generation of the reference image for the third page (3P) can start at an appropriate time after the generation of the reference image for the second page (2P). The start timing of the generation of the reference image and the generation of the inspection image is similar for subsequent pages.

[0086] [Generation of a reference image, formation of a test image on paper, and inspection and matching of the test image performed in parallel] After that, the generation of the reference image of the fifth page (5P), the formation of the inspection image of the second page (2P), and the inspection and comparison of the inspection image of the first page are executed in parallel.

[0087] In this manner, in this embodiment, a reference image is generated based on the reception of an original image (starting from the reception of the original image), and an inspection image is formed on paper when printing preparations are complete, and the inspection image is then inspected and compared. In this embodiment, the generation of the reference image and the formation, inspection, and comparison of the inspection image are performed in parallel, thereby reducing the time required for processing from the generation of the reference image to the inspection and comparison of the inspection image. As a result, productivity of printed matter is improved.

[0088] <print job> As described above, when image forming system 300 receives a print job and the inspection setting in the job information is on, it generates a reference image and forms an inspection image in parallel. Control unit 310 and print controller unit 320 control the generation of a reference image by reference image generation unit 380 and the formation of an inspection image by image formation unit 330 to be executed in parallel for one (same) print job.

[0089] Alternatively, the image forming system 300 may generate a reference image and form, inspect, and compare an inspection image using separate print jobs. The control unit 310 and print controller unit 320 control the reference image generation process (reference image generation job) and the inspection process (inspection job) to be executed in parallel. Here, the reference image generation process includes the generation of a reference image by the reference image generation unit 380. The inspection process includes the formation of an inspection image on paper by the image forming unit 330, the image inspection unit 350 scanning the paper on which the inspection image is formed, and the comparison unit 355 performing image inspection. For example, the reference image generation process may be executed by a CPU other than the image control CPU 311, and the inspection process may be executed by the image control CPU 311. Alternatively, if the control unit 310 has a multi-core CPU, the reference image generation process and the inspection process may be assigned to separate cores, and these cores may execute the reference image generation process and the inspection process in parallel.

[0090] <Process of generating reference image (step S103)> FIG. 9 is a subroutine flowchart illustrating the details of the processing procedure for generating a reference image (S103) in the flowchart shown in FIG.

[0091] First, the reference image generating unit 380 determines whether the inspection mode is the first inspection mode (step S201). If the inspection mode is the first inspection mode (step S201: YES), the reference image generating unit 380 generates reference images of the variable area and the non-variable area (step S202). After generating the reference image, the reference image generating unit 380 ends the process (return).

[0092] On the other hand, if the inspection mode is not the first inspection mode (step S201: NO), the reference image generation unit 380 determines whether the inspection mode is the second inspection mode (step S203). If the inspection mode is the second inspection mode (step S203: YES), the reference image generation unit 380 generates a reference image of the non-variable area (step S204). More specifically, the reference image generation unit 380 generates a reference image corresponding to the non-variable area, i.e., an area outside the variable area. After generating the reference image of the non-variable area, the reference image generation unit 380 ends the reference image generation process (return).

[0093] On the other hand, if the inspection mode is not the second inspection mode (step S203: NO), the reference image generating unit 380 ends the reference image generation process (image inspection) (END).

[0094] 6 and the subroutine flowchart shown in Fig. 9, when the inspection mode is the first inspection mode, reference image generation unit 380 generates a reference image for the variable area and non-variable area of ​​each page of each copy, i.e., for the entire area of ​​the print page, and inspects the inspection image. Also, when the inspection mode is the second inspection mode, reference image generation unit 380 generates a reference image for the non-variable area of ​​each page of each copy, and inspects the inspection image for the non-variable area.

[0095] The image inspection device, image inspection method, and image inspection program according to the above-described embodiments have the following advantages.

[0096] For images of pages that include variable and non-variable areas, a reference image is generated to be compared with the scanned image to be inspected, so inspection can be performed not only on non-variable areas but also on variable areas. Therefore, image defects can be detected not only in non-variable areas but also in variable areas.

[0097] Furthermore, since the image of the non-variable area is common to all copies of the original image, it is sufficient to have one reference image common to all copies of the non-variable area. On the other hand, since the image of the variable area is different for each copy, it is necessary to generate a different reference image for each copy.

[0098] As described above, the image inspection device, the image inspection method, and the image inspection program have been described in the embodiments. However, it goes without saying that those skilled in the art can appropriately add, modify, and omit the present invention within the scope of the technical concept thereof.

[0099] For example, in the above-described embodiment, a case where an original image is generated based on a print job has been described, but the present invention is not limited to such a case. The image forming unit 330 may be configured to have an image reading device 333 (see FIG. 1) that reads an original prepared by a user, and to generate an original image based on an image generated by reading the original using the image reading device 333. The image reading device 333, for example, uses a scanner to read an original transported to a predetermined reading position by an automatic document feeder, and generates image data.

[0100] The image inspection program may be provided on a computer-readable recording medium such as a USB memory, flexible disk, or CD-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is typically transferred and stored in memory or storage. The inspection program may be provided as standalone application software, or may be incorporated into the software of each device as a function of the server.

[0101] In addition, in the embodiment, part or all of the processing executed by the inspection program may be replaced with hardware such as a circuit. [Explanation of symbols]

[0102] 100 printing systems, 200 client terminals, 300 Image forming system, 310 control section, 311 Image control CPU, 312 DRAM control IC, 313 Memory, 314 image memory (DRAM), 315 Compression / Expansion IC, 316 reading processing section, 317 write processing unit, 318 Memory section, 320 Print controller section, 321 Controller control section, 322 Reference image generation control unit, 323 DRAM control IC, 324 image memory (DRAM), 325 Communications Control Section, 326 communication I / F, 330 Image forming unit, 331 Printer control unit, 332 Exposure section, 333 Image reading device, 340 Image reading unit, 341 scanner, 342 scanner control unit, 350 Imaging Department, 351 Image inspection control unit, 355 Collation Department, 356 Verification Control Unit, 360 operation display section, 361 LCD / touch sensor, 362 Operation control section, 370 Paper feed section, 380 Reference image generation unit, 390 storage device, 400 communication lines.

Claims

1. an image forming unit that forms an image on a recording medium based on image data; a reference image generating unit that generates a reference image to be used for inspecting the image formed on the recording medium based on the image data; an image inspection unit that inspects the image formed on the recording medium based on the reference image, The reference image generation unit generates a reference image for comparing with the read image inspected by the image inspection unit for an image of a page that includes a non-variable area where the same image is formed on multiple pages by the image forming unit and a variable area where a different image is formed on each page.

2. The image inspection device according to claim 1 , wherein the reference image generating unit generates the reference image for each page.

3. The image inspection device according to claim 1 , wherein the image inspection unit performs the same type of inspection on variable areas and non-variable areas included in the image.

4. a control unit that controls execution of a first inspection mode in which inspection is performed by the image inspection unit and execution of a second inspection mode in which inspection is not performed by the image inspection unit for the variable region; The control unit causing the reference image generation unit to generate the reference image for the image of the non-variable region; When the first inspection mode is executed, the reference image generating unit generates the reference image for the image of the variable region; When the second inspection mode is executed, the reference image generating unit is not caused to generate the reference image for the image of the variable region.

3. The image inspection device according to claim 1 or 2.

5. The image processing device further includes a matching unit that matches the information formed as an image with the information obtained from the read image for the variable area, The image inspection device according to claim 1 , wherein the variable region is inspected by the image inspection unit and collated by the collation unit.

6. The image inspection device according to claim 5 , wherein the inspection step by the image inspection unit and the collation step by the collation unit are performed in parallel in the variable region.

7. (a) forming an image on a recording medium based on image data; (b) generating a reference image based on the image data to be used for inspecting the image formed on the recording medium; and (c) inspecting the image formed on the recording medium based on the reference image, In the step (b), a reference image is generated for an image of a page that includes a non-variable area in which the same image is formed on multiple pages by the step (a) and a variable area in which a different image is formed on each page by the step (c), to be compared with the read image to be inspected.

8. An image inspection method as described in Claim 7, wherein in step (b), the reference image is generated for each page.

9. An image inspection method as described in claim 7 or 8, wherein in step (c), the same type of inspection is performed on variable areas and non-variable areas contained in the image.

10. The method further comprises a step (d) of controlling execution of a first inspection mode in which inspection is performed in the step (c) and execution of a second inspection mode in which inspection is not performed in the step (c), for the variable region; By the control in step (d), generating the reference image for the image of the non-variable region in the step (b); When the first inspection mode is executed, the reference image is generated for the image of the variable region in the step (b); When the second inspection mode is executed, the reference image is not generated for the image of the variable region in the step (b). The image inspection method according to claim 7 or 8.

11. The method further comprises a step (e) of comparing the image-formed information with the information obtained from the read image for the variable area, 9. The image inspection method according to claim 7, wherein the inspection in step (c) and the matching in step (e) are performed for the variable region.

12. An image inspection method as described in claim 11, in which the inspection process in step (c) and the matching process in step (e) are performed in parallel for the variable area.

13. a step (a) of forming an image on a recording medium based on image data; a step (b) of generating a reference image to be used for inspecting the image formed on the recording medium based on the image data; and (c) inspecting the image formed on the recording medium based on the reference image, An image inspection program for causing a computer to execute a process in which, in step (b), a reference image is generated for an image of a page that includes a non-variable area in which the same image is formed on multiple pages by step (a) and a variable area in which a different image is formed on each page by step (c), to be compared with the read image to be inspected by step (c).

14. An image inspection program as described in Claim 13, wherein in step (b), the reference image is generated for each page.

15. An image inspection program as described in claim 13 or 14, wherein in step (c), the same type of inspection is performed on variable areas and non-variable areas contained in the image.

16. The method further comprises a step (d) of controlling execution of a first inspection mode in which inspection is performed in the step (c) and execution of a second inspection mode in which inspection is not performed in the step (c), for the variable region; By the control in the step (d), In the step (b), the reference image is generated for the image of the non-variable region; When the first inspection mode is executed, the reference image is generated for the image of the variable region in the step (b); When the second inspection mode is executed, the reference image is not generated for the image of the variable region in the step (b). The image inspection program according to claim 13 or 14.

17. The method further comprises a step (e) of comparing the image-formed information with the information obtained from the read image for the variable area, 15. The image inspection program according to claim 13, wherein the inspection in the step (c) and the matching in the step (e) are performed for the variable region.

18. An image inspection program as described in claim 17, which performs the inspection process in step (c) and the matching process in step (e) in parallel for the variable area.

Images