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 which can further shorten a time required in processes ranging from generation of a reference image to image inspection in comparison with in a conventional technique.SOLUTION: An image inspection device 300 comprises a first control part 501, a second control part 502, and a third control part 503. The first control part 501 controls generation of a reference image that is used for inspecting an image formed on a recording medium, on the basis of obtained image data. The second control part 502 controls formation of an image on the recording medium, on the basis of the obtained image data. The third control part 503 controls execution of an inspection based on the reference image, of the image formed on the recording medium. At least one control part of the first control part 501, the second control part 502 and the third control part 503 operates independently from the other control parts.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] Conventionally, the quality of a print is inspected by comparing a read image of a print to be inspected with a preregistered reference image. The reference image may be, for example, an image of a print that is read and has no quality abnormalities. The presence or absence of quality abnormalities is determined, for example, by an inspector visually checking the image and judging whether or not there are abnormalities. For example, the image forming apparatus described in Patent Document 1 below is known as an image forming apparatus having an image inspection unit that inspects the quality of a print.

[0003] However, it takes time and effort for an inspector to visually check all pages of a printed matter to obtain a reference image, as in the image forming device of Patent Document 1. In response to this, Patent Document 2 below discloses a print inspection device that inspects the quality of a printed matter by comparing a document image as a reference image with a scanned image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-146514 A [Patent Document 2] JP 2015-53561 A Summary of the Invention [Problem to be solved by the invention]

[0005] The print inspection device of Patent Document 2 uses an original image as a reference image, thereby saving the time and effort required to create a reference image. However, it is necessary to complete the generation of the reference image (steps S101 to S115 in FIG. 6) before the generation of the inspection image (step S117 in FIG. 6) starts. Therefore, there is an issue that the process from the generation of the reference image (steps S101 to S115 in FIG. 6) to the image inspection (steps S117 to S119 in FIG. 6) still requires a considerable amount of time.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an image inspection device, an image inspection method, and an image inspection program that can further shorten the time required for processing from the generation of a reference image to image inspection compared to conventional technology. [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: a first control unit that controls the generation of a reference image used for inspecting an image formed on a recording medium based on acquired image data; a second control unit that controls the formation of the image on the recording medium based on the acquired image data; and a third control unit that controls the execution of inspection of the image formed on the recording medium based on the reference image, wherein at least one of the first control unit, the second control unit, and the third control unit operates independently of the other control units.

[0009] (2) The image inspection device according to (1) above, wherein the first control unit, the second control unit, and the third control unit are configured in a CPU with a core assigned to each control unit.

[0010] (3) The image inspection device according to (2) above, wherein the number of cores assigned to each control unit is changed based on the inspection conditions of the inspection.

[0011] (4) The image inspection device according to (3) above, wherein the inspection conditions include at least one of the number of inspection exclusion areas, the number of variable areas, the amount of information in the variable areas, and the inspection level.

[0012] (5) The image inspection device according to (2) above, wherein cores are allocated to the first control unit and the third control unit with priority over the second control unit.

[0013] (6) The image inspection device according to (2) above, wherein cores are allocated to the first control unit with priority over the third control unit.

[0014] (7) An image inspection device as described in (2) above, which, when the inspection level is changed during inspection of the image, changes the ratio of cores allocated to the first control unit and the third control unit based on the change in the inspection level.

[0015] (8) The image inspection device according to (1) above, wherein generation of the reference image and formation of an image on the recording medium are performed in parallel.

[0016] (9) An image inspection method for inspecting an image formed on a recording medium based on a print job, comprising: a first control step of controlling generation of a reference image used for inspecting the image formed on the recording medium based on acquired image data; a second control step of controlling image formation on the recording medium based on the received print job; and a third control step of controlling inspection of the image formed on the recording medium based on the received print job, wherein the first control step, the second control step, and the third control step are executed independently.

[0017] (10) An image inspection program for inspecting an image formed on a recording medium based on a print job, comprising: a first control procedure for controlling generation of a reference image based on a received print job; a second control procedure for controlling image formation on a recording medium based on the received print job; and a third control procedure for controlling inspection of the image formed on the recording medium based on the received print job, wherein the first control procedure, the second control procedure, and the third control procedure are independently executed by a computer. Effect of the Invention

[0018] According to the present invention, at least one of the first, second, and third control units operates independently of the other control units. Therefore, at least one of the steps of generating a reference image, forming an inspection image, and inspecting the reference image can be performed in parallel with the other steps, thereby shortening the time required for processing from generating the reference image to inspecting the image. As a result, the productivity of printed matter is improved. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic block diagram of a printing system according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic block diagram illustrating a configuration of the image forming system shown in FIG. 1. [Diagram 3] 3 is a block diagram for explaining an overview of the control operations of a control unit and a print controller unit shown in FIG. 2. FIG. [Figure 4] 2 is a flowchart illustrating a processing procedure of an image inspection method by the image forming system shown in FIG. 1. [Diagram 5] 5 is a subroutine flowchart illustrating details of inspection of an inspection image in the flowchart shown in FIG. 4. [Figure 6] 2 is a schematic diagram showing the time series of processes of obtaining an original image, generating a reference image, forming an inspection image, and inspecting the inspection image. FIG. [Figure 7]10 is a schematic diagram showing in chronological order the processes of acquiring an original image, generating a reference image, forming an inspection image, and inspecting the inspection image when recovery printing is performed. FIG. [Figure 8] FIG. 11 is a schematic block diagram illustrating the configuration of an image forming system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted. In addition, the dimensional ratios of the drawings are exaggerated for the convenience of explanation, and may differ from the actual ratios.

[0021] (First 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.

[0022] 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 as to be able to communicate with each other.

[0023] The client terminal 200 may be, for example, a personal computer, a tablet terminal, a smartphone, etc. 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 a 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 includes a display and can display the inspection results of the printed matter (good / defective), images of defective printed matter, etc.

[0024] The print job includes, for example, print data in a PDL (Page Description Language) format and job information. The print data includes, for example, print data consisting of the first to nth pages. The job information includes, for example, print settings such as the number of pages, the number of copies, the type of paper (recording medium), size, basis weight, single-sided printing / double-sided printing, and inspection settings (inspection on / off, inspection level). The user can issue an instruction to image forming system 300 to inspect an image by turning the inspection setting to inspection on.

[0025] The communication line 400 may include a LAN (Local Area Network) that connects computers or network devices together according to a specific standard, or a WAN (Wide Area Network) that connects LANs together with a dedicated line, etc. Examples of the specific standard include Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), and Wi-Fi (Wireless Fidelity).

[0026] The number of each of the above components connected to the communication line 400 is not limited to the example shown in FIG.

[0027] <Configuration of Image Forming System 300> 1 and 2, image forming system 300 has a control unit 310, a print controller unit 320, an image forming unit 330, an image reading unit 340, an image inspection unit 350, an operation display unit 360, a paper feed unit 370, a reference image generating unit 380, and a storage device 390. Image forming system 300 functions as an image inspection device.

[0028] In this embodiment, at least the controller control unit 321, reference image generation control unit 322, and communication control unit 325 in the print controller unit 320, and the reference image generation unit 380 constitute a first control unit 501. At least the image control CPU 311 in the control unit 310, and at least the printer control unit 331 in the image forming unit 330 constitute a second control unit 502. At least the scanner control unit 342 in the image reading unit 340, and at least the image inspection control unit 351 in the image inspection unit 350 constitute a third control unit 503.

[0029] The first control unit 501 controls the generation of a reference image used for inspecting an image formed on a sheet, based on the acquired original image (image data). The second control unit 502 controls the formation of an image on a sheet, based on the acquired original image. The third control unit 503 controls the execution of inspection of the image formed on the sheet, based on the reference image. The first control unit 501, the second control unit 502, and the third control unit 503 each have a CPU (Central Processing Unit), and at least one of the control units operates independently of the other control units. Therefore, at least one of the steps of generating the reference image, forming the inspection image, and inspecting the inspection image can be executed in parallel with the other steps.

[0030] <Configuration of control unit 310> The control unit 310 includes an image control CPU 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 storage unit 318, and the like.

[0031] The image control CPU 311 loads various programs stored in the storage unit 318 into the memory 313, and performs overall control of the operation of the entire image forming system 300 in cooperation with the loaded programs.

[0032] 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, and generates digital image (read image) data. The generated digital image data is output to the compression / expansion IC 315 by the DRAM control IC 312. The compression / expansion IC 315 performs compression processing on the digital image data and expansion 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 of the image memory (DRAM) 314 for the compressed and expanded digital image data.

[0033] The image memory 314 is made up of a DRAM and has an internal compression memory and page memory area, and temporarily stores compressed image data, decompressed image data, and the like.

[0034] The write processing unit 317 outputs the decompressed digital image data to an exposure unit 332 of the image forming unit 330 .

[0035] <Configuration of the 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 executes processes such as color conversion, screening, and rasterization to generate an original image in a bitmap format. The generated original image is transmitted to the control unit 310. The print controller unit 320 functions as an original image acquisition unit.

[0036] The print controller unit 320 is configured to include 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. In addition, the controller control unit 321 receives a print job from the client terminal 200, etc. via the communication I / F 326. The communication control unit 325 controls the communication I / F 326.

[0037] The received print job includes print data (mainly in PDL format) that is the source of the document 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 to convert the print data into bitmap data for each page based on the print settings. The RIP image after the rasterization processing is temporarily stored in the image memory 324. The RIP image in the image memory 324 is temporarily stored in the compressed memory area in the image memory 314 via the compression / decompression IC 315 under the control of the DRAM control IC 323 of the print controller unit 320 and the DRAM control IC 312 of the control unit 310. During normal printing, the RIP image stored in the compressed memory area is decompressed by the compression / decompression IC 315 and sent to the image forming unit 330 as a document image via the write processing unit 317, where it is printed.

[0038] 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.

[0039] Ideally, it is considered that the read image generated by reading the inspection image formed on paper matches the document image in terms of contents. However, when the inspection image formed on paper is read by a scanner, an error may occur in the read image with respect to the document image due to various factors such as variations in the paper transport path, deviations in the reading position by the scanner, color reproducibility, and differences in paper type. In addition, an error may occur in the document image depending on the reading resolution by the scanner. Therefore, a simple comparison between the read image and the document image is likely to cause an error, and it is not realistic to inspect the inspection image by simply comparing the read image and the document image. Therefore, in this embodiment, various processes are performed on the document image with respect to the position, resolution, color, etc., so that the image can be compared with the read image, and a reference image is generated, and the read image is compared with the reference image. As a result, the comparison with the read image is appropriately performed, and the inspection of the printed matter can be performed with high accuracy. Details of the generation process of the reference image 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.

[0040] <Configuration of Image Forming Unit 330> The image forming unit 330 forms (prints) an image on a sheet (recording medium) by an electrophotographic method including the steps of charging, exposing, developing, transferring, and fixing, according to an instruction from the control unit 310. In this embodiment, the image forming unit 330 forms an inspection image to be inspected by the image inspection unit 350 on a sheet under image forming conditions set based on the print settings. The image forming unit 330 has a printer control unit 331, an exposure unit 332, and the like. The printer control unit 331 is connected to the image control CPU 311 by serial communication, and receives control from the image control CPU 311. The printer control unit 331 drives a LD (Laser Diode) of the exposure unit 332 by a signal from the writing processing unit 317, and forms an electrostatic latent image corresponding to the document image on a photoconductor (not shown). The toner image formed on the photoconductor is developed through a developing process, and transferred onto a sheet supplied from the paper feed unit 370. The unfixed toner image on the sheet is then fixed by heating and pressing. The paper on which the toner image is fixed is transported to the image reading unit 340 .

[0041] The image forming unit 330 also includes a print sheet discharge device that distinguishes paper (waste paper) on which an inspection image detected as abnormal by the image inspection unit 350 has been formed from paper on which a normal inspection image has been formed, and discharges (purges) the paper.

[0042] <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) conveyed on the conveying path, for example, by a CCD (Charge Coupled Device) image sensor. The scanner control unit 342 controls the scanner to read the inspection image formed on the paper conveyed 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.

[0043] <Configuration of image inspection unit 350> The image inspection unit 350 performs image inspection based on the reference image. More specifically, the image inspection unit 350 obtains the reference image and the read image, and compares the reference image and the read image for each page, thereby inspecting the inspection image formed on the paper.

[0044] The image inspection unit 350 has an image inspection control unit 351. The image inspection control unit 351 has an image control CPU 311, or 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. The image inspection control unit 351, for example, calculates the difference (error) in pixel values ​​between the reference image and the read image for each page, and judges the quality of the inspection image according to the magnitude of the difference. The calculation of the difference can be performed for each page, each object, or each area. For example, when the difference is calculated for each page, if the total value of the pixel differences in one page is less than a specified value, a "good" inspection result is output, and if the total value of the differences is equal to or greater than the specified value, a "bad" inspection result is output. In addition, when the difference is calculated for each object or each area, the inspection result can be configured to be "good" or "bad" depending on the total value of the pixel differences in the selected object or area.

[0045] If the inspection result of the inspection image is "good", control unit 310 determines that the printed matter is a good product, and if the inspection result of the inspection image is "bad", control unit 310 determines that the printed matter is a defective product.

[0046] <Configuration of Operation Display Unit 360> The operation display unit 360 includes a touch panel display 361, an operation control unit 362, a numeric keypad as hard keys, a start button, a stop button, and the like. The touch panel display includes, for example, a touch sensor and an LCD (Liquid Crystal Display) arranged on the back of 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 for inputting various settings (e.g., inspection on / off and inspection level of the inspection setting) and instructions (e.g., an instruction to start printing) by the user. The operation display unit 360 is also used for outputting (displaying) the state of the image forming system 300, the inspection results of printed matter (good / bad), images of defective printed matter, and the like.

[0047] <Configuration of Paper Feeding 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.

[0048] <Configuration of the reference image generating unit 380> The reference image generating unit 380 generates a reference image based on the original image acquired by the original image acquiring unit, and outputs the generated reference image to the control unit 310. The reference image generating unit 380 can be realized by a CPU (not shown) other than the image control CPU 311 executing an image inspection program. This allows the generation of the reference image and the formation and inspection of an inspection image to be executed in parallel.

[0049] Conventionally, the same CPU is configured to generate the reference image and form and inspect the inspection image. Therefore, the CPU executes the formation and inspection of the inspection image after the generation of the reference image is completed for each page, so the generation of the reference image and the formation and inspection of the inspection image cannot be executed in parallel. In this embodiment, the generation of the reference image and the formation and inspection of the inspection image are executed by different CPUs, so the generation of the reference image and the formation and inspection of the inspection image can be executed in parallel.

[0050] Furthermore, the CPU processing load (processing time) for generating the reference image may increase or decrease depending on the complexity of the document image, the presence or absence of variable printing, etc. For example, if the document image is complex, the CPU processing 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 processing load on image control CPU 311 can be reduced.

[0051] <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 does not need to generate the reference image again by using the reference image stored in the storage device 390. Therefore, it is possible to save the time required for generating the reference image.

[0052] <Overview of Control Operations of Control Unit 310 and Print Controller Unit 320> FIG. 3 is a block diagram for explaining an overview of the control operations of the control unit 310 and the print controller unit 320 shown in FIG.

[0053] First, the control unit 310 receives an original image and job information from an original image acquisition unit (print controller unit 320) ((1) Image input). The original image is a RIP image obtained by rasterizing print data.

[0054] When the reference image generating unit 380 receives an instruction to generate a reference image from the reference image generation control unit 322 ((2)-1 instruction to generate a reference image), 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. The control unit 310 stores the reference image in the page memory 1.

[0055] As described above, the reference image generating unit 380 performs various processes on the document image with respect to the position, resolution, color, and the like to generate a reference image. For example, the reference image generating unit 380 can extract position information of the content portion from the document image and add or embed the position information in the reference image so that the content portions (contents) of the reference image and the read image can be compared. That is, the reference image generated by the reference image generating unit 380 has positioning information for aligning the reference image and the read image when performing image inspection based on the reference image. The positioning information includes contour information and edge information of the image. In addition, the reference image generated by the reference image generating unit 380 has area information on the inspection area and the inspection excluded area used when performing image inspection based on the reference image. Furthermore, the reference image generating unit 380 can adjust the resolution of the document image to match the resolution of the scanner of the image reading unit 340 to generate a reference image. Furthermore, the reference image generating unit 380 can generate a reference image by converting the color space of the original image so that the color space matches the color space (for example, RGB) used by the scanner of the image reading unit 340 .

[0056] 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. 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 performed in parallel.

[0057] When the reference image generation is completed, the reference image generation unit 380 notifies the reference image generation control unit 322 of the completion of reference image generation ((3)-1 Reference image generation completed). Furthermore, when the image formation unit 330 has completed 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).

[0058] Furthermore, upon receiving the notification that output is complete, 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 completing reading of the paper, the image reading unit 340 notifies the completion of image reading ((5)-2 Image reading completion).

[0059] Upon receiving notification that image reading is complete, the control unit 310 outputs an image inspection instruction to the image inspection unit 350 ((6)-2 Image inspection instruction). The image inspection unit 350 obtains the reference image and the read image from the page memory 1 and the page memory 2, respectively, and inspects the inspection image by comparing the reference image with the read image. Then, the image inspection unit 350 outputs the inspection result of the inspection image to the control unit 310 ((7)-2 Image inspection result).

[0060] In response to an instruction from a user, the control unit 310 performs control so that the inspection result (good / bad) of the printed matter is displayed on the operation display unit 360 or the display of the client terminal 200 based on the inspection result of the inspection image.

[0061] <Image Inspection Method Using Image Forming System 300> Fig. 4 is a flowchart illustrating the processing procedure of an image inspection method by image forming system 300 shown in Fig. 1. Fig. 5 is a subroutine flowchart illustrating the details of inspection of an inspection image in the flowchart shown in Fig. 4. The processing shown in Fig. 4 and Fig. 5 is realized by image control CPU 311 executing an image inspection program. Fig. 6 is a schematic diagram showing each process of obtaining an original image, generating a reference image, forming an inspection image, and inspecting the inspection image in chronological order.

[0062] As shown in FIG. 4, first, the control unit 310 acquires an original image (step S101). 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 nth page. For example, FIG. 6 illustrates a case in which the original images are received in order from the first page to the eighth page. In addition, in the same figure and FIG. 7, "1P" represents the first page (the same applies to "2P", etc.). In addition, "print preparation" in the formation of the test image includes initial settings and preparations of each unit (for example, warming up the fixing unit) according to the image formation conditions in the image forming unit 330.

[0063] 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.

[0064] Next, reference image generation control unit 322 controls the generation of a reference image used for inspecting the inspection image. Reference image generation unit 380 generates a reference image according to an instruction from reference image generation control unit 322 (step S103). For example, when the first page of a document image is acquired and stored in page memory 1, reference image generation control unit 322 controls reference image generation unit 380 to generate a reference image based on the first page of the document image. Reference image generation unit 380 generates a reference image based on the first page of the document image. A reference image is generated similarly for the second page of the document image.

[0065] Next, the storage device 390 stores the reference image generated by the reference image generating unit 380 (step S104). For example, the storage device 390 stores the first and second pages of the document image. In this embodiment, as shown in FIG. 6, in parallel with the processes of steps S103 and S104, the control unit 310 controls the image forming unit 330 to form an inspection image on a sheet based on the document image and job information received from the document image acquiring unit. For example, the control unit 310 performs printing preparation and controls the image forming unit 330 to form an inspection image on a sheet for the document image of the first page. The image forming unit 330 forms an inspection image on a sheet for the first page of the document image according to the instruction of the control unit 310 (step S105). After the inspection image of the document image of the first page is formed, an inspection image of the document image of the second page is also formed on a sheet in the same manner.

[0066] Next, the image inspection unit 350 determines whether a reference image has been generated for each page of the acquired document image (step S106). If a reference image has been generated (step S106: YES), the image inspection unit 350 inspects the inspection image formed by the image forming unit 330 (step S107). On the other hand, if a reference image has not been generated (step S106: NO), the image inspection unit 350 waits until a reference image is generated. For example, if a 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 S107 has not been generated, the image inspection unit 350 waits until a reference image of this document image (first page) is generated.

[0067] 6, the generation of a reference image by reference image generating unit 380 and the formation and inspection of an inspection image by image forming unit 330 are performed in parallel. This enables image forming system 300 to further reduce the time required for processing from the generation of a reference image to image inspection, as compared to the conventional technology.

[0068] [Parallel generation of a reference image and formation of a test image on paper] For example, in the example shown in the figure, the generation of the reference images of the first page (1P) and the second page (2P) and the preparation for printing are performed in parallel, and the generation of the reference image of the third page (3P) and the formation of the inspection image of the first page (1P) (first half) are performed in parallel. Then, after that, the generation of the reference image of the fourth page (4P) and the formation of the inspection image of the first page (1P) (second half) are performed in parallel. Note that in the figure, the generation of the reference image of the third page (3P) and the formation of the inspection image of the first page (1P) are shown to start simultaneously, but this is not limited to this. The formation of the inspection image of the first page (1P) can be started at an appropriate timing after the completion of the preparation for printing, and the generation of the reference image of the third page (3P) can be started at an appropriate timing after the generation of the reference image of the second page (2P). The start timing of the generation of the reference image and the generation of the inspection image is the same for the subsequent pages.

[0069] [Parallel generation of a reference image, formation of a test image on paper, and inspection of the test image] After that, generation of a reference image of the fifth page (5P), formation of an inspection image of the second page (2P), and inspection of the inspection image of the first page are executed in parallel.

[0070] As shown in FIG. 5, in the process of inspecting the inspection image, the inspection image formed on paper is read by the image reading unit 340 (step S201), and the inspection image is inspected by the image inspection unit 350 by comparing the read image with a reference image (step S202).

[0071] The control unit 310 repeats the processes of steps S101 to S107 until the inspection of the inspection images for all pages (from the first page to the final n-th page) is completed (step S108).

[0072] In this manner, in this embodiment, a reference image is generated based on reception of an original image (starting from reception of the original image), and an inspection image is formed on paper when preparations for printing are complete, and the inspection image is inspected. In this embodiment, the generation of the reference image and the formation and inspection of the inspection image are performed in parallel, so the time required for processing from the generation of the reference image to the image inspection can be shortened. As a result, productivity is improved in the series of steps up to the production of a printout without any defects.

[0073] <Print job> As described above, when the image forming system 300 receives a print job and the inspection setting in the job information is inspection on, it generates a reference image and forms an inspection image in parallel. The control unit 310 and the print controller unit 320 control the generation of a reference image by the reference image generating unit 380 and the formation of an inspection image by the image forming unit 330 to be performed in parallel by one (same) print job.

[0074] On the other hand, the image forming system 300 may realize the generation of the reference image and the formation and inspection of the inspection image by separate print jobs. The control unit 310 and the print controller unit 320 control the reference image generating process (reference image generating job) and the inspection process (inspection job) to be executed in parallel. Here, the reference image generating process includes the generation of the reference image by the reference image generating unit 380. The inspection process includes the formation of the inspection image on the paper by the image forming unit 330, and the image inspection by the image inspection unit 350 of the read image generated by reading the paper on which the inspection image is formed. For example, the reference image generating 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, when the control unit 310 has a multi-core CPU, the reference image generating process and the inspection process may be assigned to separate cores, and the reference image generating process and the inspection process may be executed in parallel by these cores.

[0075] <Recovery Print> 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, and inspecting the inspection image when recovery printing is performed.

[0076] The control unit 310 and the image forming unit 330 function as a recovery printing unit. When an abnormality is detected in the inspection image, the recovery printing unit executes reprinting (recovery printing) from the page of the document image corresponding to the page of the inspection image where the abnormality was detected. In this embodiment, the control unit 310 determines that an abnormality has been detected in the inspection image when the inspection image is defective as a result of inspection of the inspection image by the image inspection unit 350. The control unit 310 purges the paper on which the inspection image where the abnormality was detected has been formed to the outside of the image forming system 300 as waste paper.

[0077] Generally, the more complex the document image, the longer it takes for the reference image generating unit 380 to generate the reference image. For example, FIG. 7 illustrates an example in which the second page of the document image is complex and therefore the generation of the second page of the reference image takes time. The recovery printing unit executes recovery printing when the generation of the reference image is not completed before the inspection of the corresponding inspection image. For example, in the example shown in FIG. 7, the recovery printing unit waits for the completion of the generation of the reference image before performing recovery printing of the second page of the document image (the formation of the second page of the inspection image), since the generation of the second page of the reference image is not completed even after the formation of the second page of the inspection image. The control unit 310 purges the paper of the second page of the inspection image that has already been printed. This prevents the paper on which the uninspected inspection image is formed from being mixed with the paper on which the normal inspection image is formed.

[0078] Furthermore, during recovery printing, the image inspection unit 350 can perform image inspection using the reference image stored in the storage device 390. This eliminates the need for the reference image generation unit 380 to generate the reference image again, thereby saving the time required for generating the reference image.

[0079] Furthermore, when recovery printing is performed, the document image stored in the page memory 1 in step S102 of FIG. 4 can be configured to be stored in the storage device 390. By using the document image stored in the storage device 390, the processes of steps S101 and S102, as well as the processes of generating and storing a reference image (steps S103 and S104), become unnecessary. Therefore, the control unit 310 and the print controller unit 320 control the print job so that only the processes of forming and inspecting an inspection image are executed. This can shorten the time it takes from the start of a print job to the completion of inspection of the printed matter. As a result, the productivity of printed matter is improved.

[0080] <Effects of the First Embodiment> The image inspection device, the image inspection method, and the image inspection program according to the first embodiment described above can achieve the following effects.

[0081] The first control unit 501, the second control unit 502, and the third control unit 503 each have a CPU, and at least one of the control units operates independently of the other control units. Therefore, in the steps of generating a reference image, forming an inspection image, and inspecting the reference image, at least one of the steps can be executed in parallel with the other steps. As a result, the time required for the processing from generating the reference image to inspecting the image can be shortened.

[0082] Second Embodiment In the first embodiment, the first to third control units 501 to 503 are configured by separate CPUs. In the second embodiment, the first to third control units 501 to 503 are configured by a multi-core CPU with a core assigned to each control unit. In the following description, in order to avoid duplication, description of the same configuration as in the first embodiment will be omitted or simplified.

[0083] 8 is a schematic block diagram illustrating the configuration of an image forming system according to the second embodiment. The diagram shows that in the initial state, cores 0, 1, 2, and 3 of one multi-core CPU are assigned to first to third control units 501 to 503, respectively. Note that, although the diagram illustrates a four-core CPU, the number of cores in the multi-core CPU of this embodiment is not limited to four, and may be six or more.

[0084] <Core allocation> The number of cores assigned to each of the first to third control units 501 to 503 can be changed. In this embodiment, for example, the number of cores assigned to each control unit can be changed based on the inspection conditions in the inspection of the inspection image. The inspection conditions include at least one of the number of inspection excluded areas, the number of variable areas, the amount of information in the variable areas, and the inspection level. The inspection excluded areas are areas that are excluded from the detection of abnormalities in the inspection of the inspection image. The variable areas are areas where variable printing is performed. Variable printing refers to printing in which the printed content of each sheet can be partially replaced as necessary. The inspection level (inspection level) is the degree of strictness when inspecting the quality, and can be selected from a plurality of levels such as "mild," "normal," and "strict." The user can set the inspection level in the inspection settings of the print settings. The user can also change the inspection level through the operation display unit 360 even after the inspection of the inspection image has started.

[0085] The processing load (processing time) of the core in generating the reference image may increase or decrease depending on the complexity of the document image, the presence or absence of variable printing, etc. For example, if the document image is a complex image, the processing load in generating the reference image may increase significantly. In addition, the processing load of the core in image processing for forming the inspection image may also increase or decrease depending on the complexity of the document image, the presence or absence of variable printing, etc. However, in forming the inspection image, the time required for paper transport and fixing is relatively large compared to the time required for image processing. Therefore, in forming the inspection image, if averaged over time, the processing load of the core for image processing is often not large. In addition, the processing load of the core in inspecting the inspection image may increase or decrease depending on the number of inspection excluded areas, the number of variable areas, the amount of information in the variable areas, and the inspection level.

[0086] For example, the greater the number of inspection-exclusion regions, the smaller the amount of processing that cores 2 and 3 must perform in inspecting the inspection image, and therefore the number of cores allocated to inspecting the inspection image of the third control unit 503 can be reduced. Therefore, the number of cores allocated to the first control unit 501 can be increased by the amount of the reduction in the number of cores required for inspecting the inspection image. For example, when the number of inspection-exclusion regions is large, the allocation can be changed so that core 3 that was allocated to the third control unit 503 is allocated to the first control unit 501.

[0087] Furthermore, since the processing load for generating a reference image increases as the number of variable regions and the amount of information in the variable regions increase, it is preferable to increase the number of cores allocated to the first control unit 501 .

[0088] Furthermore, when the inspection level is "strict", the processing load for inspecting the inspection image is large, so it is preferable to maintain or increase the number of cores allocated to the third control unit 503. On the other hand, when the inspection level is "gentle", the processing load for inspecting the inspection image is small, so the number of cores allocated to inspecting the inspection image can be reduced.

[0089] <Core allocation priority> As described above, the possibility that the processing load of the core increases or decreases for the generation of the reference image and the inspection of the inspection image is high, whereas the possibility that the processing load of the core increases or decreases for the formation of the inspection image is low. Therefore, in this embodiment, the first control unit 501 and the third control unit 503 are configured to be assigned cores with priority over the second control unit 502. For example, more cores may be assigned to the first control unit 501 and the third control unit 503 than to the second control unit 502. Also, when the cores of the first control unit 501 or the third control unit 503 and the cores of the second control unit 502 have the same usage rate, more cores may be assigned to the first control unit 501 or the third control unit 503.

[0090] Also, for example, when the original image is a complex image, the processing load of the cores for generating the reference image may increase significantly. Also, the processing load of generating the reference image is often higher than that of inspecting the inspection image. Therefore, the cores are allocated to the first control unit 501 with priority over the third control unit 503. For example, more cores may be allocated to the first control unit 501 than to the third control unit 503. Also, when the cores of the first control unit 501 and the cores of the third control unit 503 have the same usage rate, more cores may be allocated to the first control unit 501.

[0091] In this manner, cores are allocated preferentially to the first control unit 501, the third control unit 503, and the second control unit 502 in that order.

[0092] <Change in core allocation ratio based on change in inspection level> When the inspection level is changed during inspection of an inspection image, the ratio of the number of cores allocated to the first control unit 501 and the third control unit 503 is changed based on the change in the inspection level. For example, the ratio of the number of cores of the first control unit 501 to the number of cores of the third control unit 503 is changed according to the changed inspection level. More specifically, when the inspection level is "strict", the ratio of core allocation is changed so that the ratio of the number of cores of the first control unit 501 to the number of cores of the third control unit 503 becomes smaller. On the other hand, when the inspection level is "lenient", the ratio of core allocation is changed so that the ratio of the number of cores of the first control unit 501 to the number of cores of the third control unit 503 becomes larger.

[0093] In addition, if the processing load on a core for generating a reference image is greater than the processing load on a core for inspecting an inspection image, the core allocation ratio is changed so that the ratio of the number of cores of the first control unit 501 to the number of cores of the third control unit 503 becomes larger.

[0094] <Effects of the Second Embodiment> The image inspection device, the image inspection method, and the image inspection program according to the second embodiment described above can achieve the following effects.

[0095] The first control unit 501, the second control unit 502, and the third control unit 503 are configured in a multi-core CPU with each control unit assigned a core. With this configuration, at least one of the control units operates independently of the other control units. Therefore, at least one of the steps of generating a reference image, forming an inspection image, and inspecting the reference image can be executed in parallel with the other steps. As a result, the time required for the process from generating the reference image to inspecting the image can be reduced.

[0096] 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.

[0097] For example, in the above 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 generate an original image based on an image generated by reading the original using the image reading device 333. For example, the image reading device 333 uses a scanner to read an original transported to a predetermined reading position by an automatic document feeder, and generates image data.

[0098] The image inspection program may be provided by a computer-readable recording medium such as a USB memory, a flexible disk, or a CD-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded in the computer-readable recording medium is usually transferred and stored in a memory or storage. The inspection program may be provided as a standalone application software, or may be incorporated into the software of each device as a function of the server.

[0099] Furthermore, in the embodiment, a part or all of the processing executed by the inspection program may be replaced with hardware such as a circuit. [Explanation of symbols]

[0100] 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 section, 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 Communication 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 Inspection Department, 351 Image inspection control unit, 360 operation display section, 361 LCD / touch sensor, 362 Operation control section, 370 Paper feed section, 380 Reference image generating unit, 390 storage device, 400 communication lines, 501 first control section, 502 second control section, 503 Third control section.

Claims

1. A first control unit controls generation of a reference image used for inspecting an image formed on a recording medium based on the acquired image data; a second control unit that controls formation of the image on the recording medium based on the acquired image data; a third control unit that controls execution of an inspection of the image formed on the recording medium based on the reference image; An image inspection device, wherein at least one of the first control unit, the second control unit, and the third control unit operates independently of the other control units.

2. The image inspection device according to claim 1 , wherein the first control unit, the second control unit, and the third control unit are configured by allocating a core to each control unit in a CPU.

3. The image inspection device according to claim 2 , wherein the number of cores assigned to each control unit is changed based on an inspection condition of the inspection.

4. The image inspection device according to claim 3 , wherein the inspection conditions include at least one of the number of inspection exclusion areas, the number of variable areas, an amount of information in a variable area, and an inspection level.

5. The image inspection device according to claim 2 , wherein cores are allocated to the first control unit and the third control unit with a higher priority than to the second control unit.

6. The image inspection device according to claim 2 , wherein cores are allocated to the first control unit with a higher priority than the third control unit.

7. 3. The image inspection device according to claim 2, wherein, when an inspection level is changed during inspection of the image, a ratio of cores allocated to the first control unit and the third control unit is changed based on the change in the inspection level.

8. 2. The image inspection device according to claim 1, wherein the generation of the reference image and the formation of the image on the recording medium are performed in parallel.

9. 1. An image inspection method for inspecting an image formed on a recording medium based on a print job, comprising: a first control step of controlling generation of a reference image used for inspecting an image formed on a recording medium based on the acquired image data; a second control step of controlling image formation on a recording medium based on the received print job; and a third control step of controlling an inspection of an image formed on a recording medium based on the received print job, An image inspection method, characterized in that the first control step, the second control step, and the third control step are executed independently.

10. An image inspection program for inspecting an image formed on a recording medium based on a print job, a first control procedure for controlling generation of a reference image based on a received print job; a second control procedure for controlling image formation on a recording medium based on the received print job; and a third control procedure for controlling an inspection of an image formed on a recording medium based on the received print job, An image inspection program, characterized in that the first control procedure, the second control procedure, and the third control procedure are independently executed by a computer.

Images