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

Abstract

To provide an image inspection system, an image inspection device, an image inspection method, and an image inspection program with which it is possible to prevent or reduce a situation where inspection of an inspection image is executed before a storage area for storing the inspection image and a reference image in a storage during image inspection is secured.SOLUTION: An image inspection system 100 has a reference image creation unit 380, an image inspection unit 350, a first storage unit, and a second storage unit. The reference image creation unit 380 creates a reference image used for inspection of an image formed on a recording medium. The image inspection unit 350 conducts, on the basis of the reference image, inspection of an image to be inspected created by reading the image formed on the recording medium. The first storage unit stores the reference image being created by the reference image creation unit 380 during the creation of the image to be inspected. The second storage unit stores the image to be inspected.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Conventionally, there has been known a method for inspecting the quality of a printed matter by comparing a read image obtained by reading a print sheet (printed matter) on which a test image has been printed with a reference image (for example, see Patent Document 1 below). In Patent Document 1, a user inspects several printed matters on which a test image has been printed, and the read image of the printed matter that is determined to be free of abnormalities is used as the reference image.

[0003] There is also known a method of inspecting the quality of a printed matter by using an original image as a reference image and comparing the original image with a scanned image of the printed matter (for example, see Patent Document 2 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-146514 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-53561 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming device of Patent Document 1, a user inspection is required to generate a reference image to be used in the actual printing. Furthermore, the reference image must be prepared before the actual printing begins, and then the actual printing is performed. Furthermore, in the print inspection device of Patent Document 2, the generation of the reference image (steps S101 to S115 in FIG. 6) must be completed before the generation of the inspection image (step S117 in FIG. 6 of the same document) begins. Therefore, there is a problem in 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] In contrast, no technology has been proposed to date that simultaneously performs the generation process of a reference image and the inspection process of an inspection image. In order to shorten the time required for the processes from the generation of a reference image to the image inspection, the present inventor is developing a technology that simultaneously performs the generation process of a reference image and the inspection process of an inspection image in parallel, and sequentially performs image inspection using the generated reference image. However, depending on the inspection timing of the inspection image and the size of the reference image, a situation may arise in which it is not possible to secure storage space in a storage device to store the inspection image and the reference image. In other words, the inability to secure storage space in a storage device to store the inspection image and the reference image during image inspection can be a factor in preventing normal image inspection.

[0007] The present invention has been made in view of the above circumstances, and aims to provide an image inspection system, an image inspection device, an image inspection method, and an image inspection program that can prevent or suppress a situation in which inspection of an inspection image is performed without securing storage space in a storage device for storing an inspection image and a reference image during image inspection. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following means.

[0009] (1) An image inspection system comprising: a reference image generation unit that generates a reference image to be used for inspecting an image formed on a recording medium; an image inspection unit that inspects an image to be inspected that is generated by reading the image formed on the recording medium based on the reference image; a first memory unit that stores the reference image being generated by the reference image generation unit while the image to be inspected is being generated; and a second memory unit that stores the image to be inspected.

[0010] (2) The image inspection system according to (1) above, further comprising a control unit that controls the reference image generation process and the inspection process of inspecting the image so that they are carried out in parallel.

[0011] (3) An image inspection system as described in (1) above, further comprising an acquisition unit that acquires a job for forming the image on the recording medium, and further comprising a control unit that controls the storage device to reserve the first memory unit and the second memory unit based on the acquisition of the job.

[0012] (4) The image inspection system according to (3) above, wherein the control unit controls the first storage unit and the second storage unit to be allocated for each page of the job.

[0013] (5) An image inspection system as described in (1) above, further comprising a control unit that controls the storage device to reserve the first memory unit and the second memory unit before the image inspection unit performs the inspection, and if the first memory unit and the second memory unit cannot be reserved, the image inspection unit does not perform the inspection.

[0014] (6) The image inspection system described in (1) above, further comprising a first erasure unit that erases the reference image stored in the first memory unit for each page based on completion of inspection for each page by the image inspection unit.

[0015] (7) An image inspection system as described in (1) or (6) above, further comprising a second erasure unit that erases the inspection target image stored in the second memory unit for each page based on the completion of inspection for each page by the image inspection unit.

[0016] (8) An image inspection system as described in (1) or (2) above, wherein the image inspection unit performs inspection based on the reference image stored in the first memory unit and the image to be inspected stored in the second memory unit.

[0017] (9) An image inspection device comprising: an image acquisition unit that acquires a reference image used for inspecting an image formed on a recording medium, the reference image being generated by a reference image generation unit, and an inspection target image generated by reading the image formed on the recording medium; an image inspection unit that inspects the inspection target image based on the reference image; a first memory unit that stores the reference image being generated by the reference image generation unit while the inspection target image is being generated; and a second memory unit that stores the inspection target image.

[0018] (10) An image inspection method comprising the steps of: (a) generating a reference image to be used in inspecting an image formed on a recording medium; (b) inspecting an image to be inspected that is generated by reading the image formed on the recording medium based on the reference image; (c) storing the reference image being generated in step (a) in a first memory unit during the generation of the image to be inspected; and (d) storing the image to be inspected in a second memory unit.

[0019] (11) An image inspection program for causing a computer to execute a process including the steps of: (a) generating a reference image to be used in inspecting an image formed on a recording medium; (b) inspecting an image to be inspected that is generated by reading the image formed on the recording medium based on the reference image; (c) storing the reference image being generated in step (a) in a first memory unit during the generation of the image to be inspected; and (d) storing the image to be inspected in a second memory unit. [Effects of the Invention]

[0020] According to the present invention, the system has a first storage unit that stores the reference image being generated by the reference image generation unit while the image to be inspected is being generated, and a second storage unit that stores the image to be inspected. This reduces the time required for processing from the generation of the reference image to the image inspection, and prevents or suppresses a situation in which inspection of the inspection image is performed without securing storage space in the storage device for storing the inspection image and the reference image during image inspection. [Brief explanation of the drawings]

[0021] Advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for purposes of illustration only and are not intended to define the limits of the invention. [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] 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 4] 2 is a flowchart illustrating a processing procedure of an image inspection method performed by the image forming system shown in FIG. 1. [Figure 5] 5 is a subroutine flowchart illustrating the details of the inspection image formation process and inspection process (step S106) shown in FIG. 4. [Figure 6] 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, and inspecting the inspection image. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the disclosed embodiments. In the description of the drawings, the same elements are given 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.

[0023] (Embodiment) <Printing system configuration> FIG. 1 is a schematic block diagram of a printing system according to an embodiment of the present invention, and FIG. 2 is a schematic block diagram illustrating the configuration of the image forming system shown in FIG.

[0024] 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.

[0025] 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.

[0026] A print job includes, for example, print data in PDL (Page Description Language) format and job information. The print data includes, for example, print data consisting of pages 1 to n. The job information includes, for example, print settings such as the number of pages, number of copies, paper (recording medium) type, size, basis weight, single-sided printing / double-sided printing, and inspection setting (on / off). By turning on the inspection setting, the user can issue an instruction to the image forming system 300 to inspect the image.

[0027] 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).

[0028] The number of the above components connected to the communication line 400 is not limited to the example shown in FIG.

[0029] <Configuration of Image Forming System 300> 1 and 2, image forming system (image inspection 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 (image inspection device) 350, an operation display unit 360, a paper feed unit 370, and a reference image generation unit 380. Image forming system 300 functions as an image inspection system.

[0030] <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.

[0031] 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.

[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 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.

[0033] Image memory 314 is configured with DRAM, has areas for compression memory and page memory, and temporarily stores compressed image data, decompressed image data, etc. Control unit 310 controls the page memory to allocate a first memory unit and a second memory unit before inspection by image inspection unit 350. The memory address spaces of the first memory unit and the second memory unit in image memory 314 are managed by image control CPU 311. Control unit 310 can be configured to estimate the data sizes of the reference image and the scanned image based on the print data, and to allocate the first memory unit and the second memory unit to image memory 314, each having a size corresponding to the estimated data sizes of the reference image and the scanned image. The reference image and the scanned image are stored in the allocated first memory unit and second memory unit, respectively. Image memory 314 functions as a storage device.

[0034] The first storage unit is an area for storing the reference image generated by the reference image generation unit 380. In particular, in this embodiment, the first storage unit stores the reference image being generated by the reference image generation unit 380 while the inspection object image is being generated. The inspection object image is a read image obtained by reading an inspection image formed on paper by the image reading unit 340. In this embodiment, the period during which the inspection object image is being generated includes not only the generation of the read image by the image reading unit 340 but also the formation of the inspection image on paper by the image forming unit 330. The inspection object image is stored in the second storage unit.

[0035] For example, when a reference image is stored in the first storage unit, control unit 310 associates information about the page of the corresponding test image (e.g., a page number) with the reference image and stores it in the first storage unit. Control unit 310 has a function of determining, for each page, whether a reference image corresponding to the test image is stored in the first storage unit by referring to the information about the page in the first storage unit. For example, control unit 310 may determine whether a reference image corresponding to the test image is stored in the first storage unit immediately before inspecting the test image and output the determination result. Control unit 310 may also determine whether the test image is stored in the second storage unit immediately before inspecting the test image and output the determination result. Control unit 310 may also be configured to determine whether a test image and a reference image corresponding to the test image have been stored at any determination timing, not just immediately before inspection, during the image formation process from the start of image formation to the completion of image formation, and during the reading process from the start of reading the test image to the completion of reading.

[0036] The control unit 310 also functions as a first erasing unit and can erase the reference image stored in the first storage unit page by page based on the completion of inspection for each page by the image inspection unit 350. The control unit 310 also functions as a second erasing unit and can erase the inspection target image stored in the second storage unit page by page based on the completion of inspection for each page by the image inspection unit 350.

[0037] <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.

[0038] The print controller unit 320 is configured with a controller control unit 321, 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.

[0039] 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.

[0040] The write processing unit 317 outputs the decompressed digital image data to an exposure unit 332 of the image forming unit 330 .

[0041] In this embodiment, the control unit 310 can perform control to secure a first storage unit and a second storage unit in the image memory 314 based on, for example, acquisition of a print job. More specifically, the control unit 310 allocates areas for the first storage unit and the second storage unit in the image memory 314 at the timing when the print controller unit 320 acquires the print job.

[0042] The control unit 310 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, the timing when the inspection setting is on and the document image acquisition unit acquires the document image. The reference image generation unit 380 generates the reference image based on the reference image generation instruction.

[0043] 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.

[0044] <Configuration of Image Forming Unit 330> The image forming unit 330 forms (prints) an image on paper using an electrophotographic process, including charging, exposure, development, transfer, and fixing processes, in accordance with instructions from the control unit 310. In this embodiment, the image forming unit 330 forms an inspection image, which is inspected by the image inspection unit 350, on paper using image formation conditions set based on print settings. 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 the LD (laser diode) of the exposure unit 332 in response to a signal from the write processing unit 317, forming an electrostatic latent image corresponding to the original image on a photoconductor (not shown). The toner image formed on the photoconductor is developed through a development 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 .

[0045] 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 detected as abnormal by the image inspection unit 350 has been formed, from paper on which a normal inspection image has been formed.

[0046] <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.

[0047] <Configuration of image inspection unit 350> The image inspection unit 350 inspects a read image (image to be inspected) generated by reading an image formed on paper based on a reference image. More specifically, the image inspection unit 350 acquires the reference image and the read image, and inspects the inspection image formed on paper by comparing the reference image and the read image for each page.

[0048] The image inspection unit 350 includes an image inspection control unit 351. The image inspection control unit 351 includes an image control CPU 311 or a CPU, RAM, ROM, and auxiliary storage device (not shown). The inspection function of 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 scanned image for each page and determines the pass / fail of the inspection image based 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, a "pass" inspection result is output; if the total value of the differences is equal to or greater than the specified value, a "fail" inspection result is output. Furthermore, when calculating the difference for each object or region, the system can be configured to output a "pass" or "fail" inspection result based 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 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) 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), images of defective printed materials, etc.

[0051] <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.

[0052] <Configuration of Reference Image Generator 380> Reference image generation unit 380 generates a reference image to be used in inspecting an image formed on paper based on the original image acquired by the original image acquisition unit, and outputs the generated reference image to control unit 310. Reference image generation unit 380 can be realized by a CPU (not shown) separate from image control CPU 311 executing an image inspection program. This allows the generation of a reference image and the formation and inspection of an inspection image to be performed in parallel. Alternatively, if image control CPU 311 is a multi-core CPU, reference image generation unit 380 may be assigned to a core separate from the processing of forming and inspecting an inspection image, and the generation of a reference image and the formation and inspection of an inspection image may be performed in parallel by separate cores.

[0053] 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.

[0054] Furthermore, if the original image is complex, 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.

[0055] <Outline of Control Operations of Control Unit 310 and Print Controller Unit 320> FIG. 3 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.

[0056] 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. The control unit 310 allocates a first storage unit and a second storage unit in the image memory 314. The control unit 310 saves the original image in the image memory 314.

[0057] When the reference image generating unit 380 receives an instruction to generate a reference image from the control unit 310 ((2)-1 instruction to generate a reference image), it generates a reference image based on the original image acquired by the original image acquiring unit and outputs it to the control unit 310.

[0058] As described above, the reference image generation unit 380 generates a reference image by performing various processes on the document image regarding position, resolution, color, etc. For example, the reference image generation unit 380 can extract position information of content portions 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 scanned image can be compared. That is, the reference image generated by the reference image generation unit 380 includes 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 includes 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 document 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 .

[0059] 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 image memory 314 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.

[0060] When the reference image generation unit 380 completes the generation of the reference image, it notifies the control unit 310 of the completion of reference image generation ((3)-1 Reference image generation completed). Furthermore, when the image forming unit 330 completes image formation on the paper, it notifies the control unit 310 of the completion of output ((3)-2 Output completed). In this embodiment, the first storage unit stores the reference image being generated by the reference image generation unit 380 while the inspection image is being generated. The generated reference image is stored in the storage area for the reference image in the first storage unit ((4)-1 Save reference image).

[0061] 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 second storage unit. Upon completion of reading the paper, the image reading unit 340 notifies the completion of image reading ((5)-2 Image reading completion).

[0062] Upon receiving notification that the 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 control unit 310 determines for each page whether a reference image corresponding to the inspection image is stored in the first storage unit. The image inspection unit 350 obtains the reference image and the read image from the first storage unit and the second storage unit, 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). The control unit 310 also accepts the inspection results of the inspection image as a notification of the completion of inspection by the image inspection unit 350. When the control unit 310 accepts the notification of the completion of inspection, it erases the reference image stored in the first storage unit and the read image stored in the second storage unit for each page. Note that image data is deleted from the first storage unit and the second storage unit by the control unit 310 performing a memory management operation to free up the storage areas corresponding to the first storage unit and the second storage unit. When the storage areas are freed up, the image data stored in the storage areas may be overwritten with "0" or the like, or the original data may remain stored without being overwritten with "0" or the like.

[0063] In response to an instruction from the user, the control unit 310 controls the operation display unit 360 or the display of the client terminal 200 to display the inspection result (good / bad) of the printed matter based on the inspection result of the inspection image.

[0064] <Image Inspection Method Using Image Forming System 300> Fig. 4 is a flowchart illustrating the processing procedure of an image inspection method using the image forming system shown in Fig. 1. Fig. 5 is a subroutine flowchart illustrating the details of the processing procedure for forming and inspecting the inspection image (step S106) shown in Fig. 4. The processes shown in Figs. 4 and 5 are realized by image control CPU 311 executing an image inspection program. Fig. 6 is a schematic diagram showing the time series of processes for obtaining an original image, generating a reference image, forming an inspection image, and inspecting the inspection image.

[0065] 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 where the original images are received in order from the first page to the eighth page.

[0066] Next, the control unit 310 allocates a first storage unit (step S102). More specifically, the control unit 310 allocates a first storage unit in the image memory 314 (storage device) for each page of the job.

[0067] Next, the control unit 310 determines whether the first storage unit has been allocated (step S103). The control unit 310 compares, for example, the remaining capacity of the image memory 314 that can be used to store the reference image with the size of the expected reference image. The control unit 310 determines that the first storage unit has been allocated if the remaining capacity of the image memory 314 is equal to or greater than the size of the expected reference image. If the remaining capacity of the image memory 314 is less than the size of the reference image, the control unit 310 determines that the first storage unit has not been allocated. If the first storage unit has been allocated (step S103: YES), the control unit 310 proceeds to the next step S104. When a print job is started, the control unit 310 saves the original images acquired from the original image acquisition unit one page at a time in the image memory 314. On the other hand, if the first storage unit has not been allocated (step S103: NO), the control unit 310 proceeds to the process of step S109. If the first storage unit has not been allocated, the control unit 310 cannot issue an image inspection instruction to the image inspection unit 350. Therefore, image inspection unit 350 will not (cannot) inspect the inspection image unless the first storage unit is secured. In step S109, control unit 310 repeats the processes of steps S101 to S108 and S110 until inspection of the inspection images for all pages (from the first page to the final nth page) is completed.

[0068] Next, the control unit 310 allocates a second storage unit (step S104). More specifically, the control unit 310 allocates a second storage unit for each page of the job in the image memory 314 (storage device).

[0069] Next, if the first storage unit has been allocated (step S103: YES), the control unit 310 determines whether the second storage unit has been allocated (step S105). If the second storage unit has been allocated (step S105: YES), the control unit 310 proceeds to the next step, S106.

[0070] On the other hand, if the second storage unit has not been secured (step S105: NO), the control unit 310 proceeds to the process of step S110. If the first storage unit and the second storage unit cannot be secured, the control unit 310 cannot issue an image inspection instruction to the image inspection unit 350. Therefore, the image inspection unit 350 will not (cannot) inspect the inspection image unless both the first storage unit and the second storage unit are secured. In step S110, the control unit 310 releases the first storage unit. The control unit 310 releases the first storage unit by releasing the storage area corresponding to the first storage unit in the image memory 314, and proceeds to the process of step S109.

[0071] In step S106, control unit 310 generates a reference image and performs processing to form and inspect an inspection image. The reference image generated by reference image generation unit 380 is stored in a first storage unit. The inspection image printed on paper by image formation unit 330 is read by image reading unit 340, and the read image is stored in a second storage unit. Image inspection unit 350 inspects the inspection image based on the reference image in the first storage unit and the read image in the second storage unit. Details of the processing in step S106 will be described later.

[0072] Next, the control unit 310 releases the first storage unit and the second storage unit (steps S107 and S108). Once the inspection of the inspection image is complete, the reference image and the scanned image are no longer needed, so the control unit 310 releases the storage areas in the image memory 314 that correspond to the first storage unit and the second storage unit.

[0073] Next, the control unit 310 determines whether or not the inspection of all pages has been completed (step S109). If the inspection of all pages has been completed (step S109: YES), the control unit 310 ends the process (END). On the other hand, if the inspection of all pages has not been completed (step S109: NO), the control unit 310 returns to the process of step S101.

[0074] <Generation of Reference Image, and Inspection Image Formation and Inspection Processing (Step S106)> As shown in FIG. 5, reference image generating unit 380 generates a reference image to be used for inspecting the inspection image (step S201). Control unit 310 controls the generation of the reference image. Reference image generating unit 380 generates the reference image in accordance with an instruction from control unit 310. For example, when the first page of the document image is acquired and stored in image memory 314, control unit 310 controls reference image generating unit 380 to generate a reference image based on the first page of the document image. Reference image generating unit 380 generates a reference image based on the first page of the document image. A reference image is similarly generated for the second page of the document image.

[0075] Next, the first storage unit stores the reference images generated by the reference image generating unit 380 (step S202). For example, the first storage unit stores the reference images corresponding to the first and second pages of the document image.

[0076] In parallel with the processing of steps S201 and S202, control unit 310 controls 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. For example, control unit 310 performs printing preparation and controls image forming unit 330 to form an inspection image on paper for the first page of the original image. Image forming unit 330 forms an inspection image on paper for the first page of the original image in accordance with instructions from control unit 310 (step S203). After the inspection image for the first page of the original image is formed, an inspection image for the second page of the original image is similarly formed on paper. After the paper has been ejected, image forming unit 330 notifies control unit 310 that the paper has been ejected.

[0077] Next, the control unit 310 instructs the image reading unit 340 to read the image. The image reading unit 340 reads the test image formed on the paper (step S204).

[0078] Next, the image reading unit 340 stores the read image of the inspection image in a storage area for read images in the second storage unit (step S205). The image reading unit 340 notifies the control unit 310 that reading of the inspection image has been completed.

[0079] Next, the control unit 310 determines whether a reference image for each page of the acquired document image has been stored in the first storage unit (step S206). That is, after reading the image formed on the paper based on the test image, the control unit 310 determines for each page whether a reference image corresponding to the test image has been stored in the first storage unit. For example, the control unit 310 determines whether a page corresponding to the page of the test image formed by the image forming unit 330 has been stored in the first storage unit. If a reference image has been stored (step S206: YES), the image inspection unit 350 compares the reference image with the read image to inspect the test image (step S207). The image inspection unit 350 notifies the control unit 310 of the inspection result.

[0080] On the other hand, if the reference image has not been stored (step S206: NO), control unit 310 ends the process (returns). If the reference image has not been stored in the first storage unit, control unit 310 cannot compare the reference image with the test image, and therefore ends the process without testing the test image.

[0081] 5, the generation of a reference image by reference image generation unit 380 and the formation and inspection of an inspection image by image formation unit 330 are performed in parallel. This enables image formation system 300 to further reduce the time required for processing from the generation of a reference image to image inspection compared to conventional techniques.

[0082] [Parallel generation of reference image and formation of test image on paper] For example, in the example shown in FIG. 5, the generation of reference images for the first page (1P) and the second page (2P) and printing preparation are performed in parallel, and the generation of the reference image for the third page (3P) and the formation of the inspection image for the first page (1P) are performed in parallel. Then, the generation of the reference image for the fourth page (4P) and the formation of the inspection image for the first page (1P) are performed in parallel. Note that in the same figure, the generation of the reference image for the third page (3P) and the formation of the inspection image for the first page (1P) are shown to start simultaneously, but this is not limited to this. The formation of the inspection image for the first page (1P) can start at an appropriate time after the completion of printing preparation, 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 the same for subsequent pages.

[0083] [Generating a reference image, forming a test image on paper, and inspecting the test image 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 of the inspection image of the first page are executed in parallel.

[0084] As described above, 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 then an inspection image is formed on paper when printing preparations are complete, and the inspection image is inspected. Furthermore, because the generation of the reference image and the formation and inspection of the inspection image are performed in parallel, the time required for the process from the generation of the reference image to the image inspection can be shortened. As a result, the productivity of printed matter is improved. Furthermore, before inspecting the inspection image, the reference image is stored in the first storage unit, and it is determined whether the inspection image is saved in the second storage unit. Therefore, while shortening the time required for the process from the generation of the reference image to the image inspection, it is possible to prevent or suppress a situation in which inspection of the inspection image is performed without securing storage space in the storage device for storing the inspection image and the reference image during image inspection.

[0085] <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.

[0086] Alternatively, the image forming system 300 may generate a reference image and form and inspect an inspection image using separate print jobs. The control unit 310 and the 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 and the image inspection unit 350 inspecting the scanned image generated by scanning the paper on which the inspection image is formed. 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.

[0087] As described above, the image forming system, 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.

[0088] For example, in the above embodiment, the control unit 310 is responsible for instructing the reference image generation unit 380 to generate a reference image, but the present invention is not limited to this. For example, the scanner control unit 342 or the image inspection control unit 351 may be configured to instruct the reference image generation unit 380 to generate a reference image. Furthermore, the reference image generation unit 380 may be mounted on the image reading unit 340 or the image inspection unit 350.

[0089] Furthermore, in the above-described embodiment, the first and second storage units are stored in the image memory 314 of the control unit 310. However, the present invention is not limited to this. For example, the first and second storage units may be configured to be stored in memory within the scanner control unit 342 or the image inspection control unit 351. For example, the image inspection unit 350 may be configured such that the image inspection control unit 351 functions as an image acquisition unit that acquires the reference image and the read image, and stores the reference image and the read image in the first and second storage units stored within the image inspection control unit 351, respectively. The image inspection unit 350 can also function independently as an image inspection device by inspecting the read image stored in the second storage unit based on the reference image stored in the first storage unit.

[0090] Furthermore, 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. 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.

[0091] 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.

[0092] 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.

[0093] While embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are made for purposes of illustration and example only and are not intended to be limiting, and the scope of the present invention should be construed by the language of the appended claims. [Explanation of symbols]

[0094] 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, 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, 360 operation display section, 361 LCD / touch sensor, 362 Operation control section, 370 Paper feed section, 380 Reference image generation unit, 400 communication lines.

Claims

1. a reference image generating unit that generates a reference image used for inspecting an image formed on a recording medium; an image inspection unit that inspects an inspection target image generated by reading the image formed on the recording medium based on the reference image; a first storage unit that stores the reference image being generated by the reference image generation unit during generation of the inspection object image; a second storage unit that stores the inspection target image; An image inspection system comprising:

2. The image inspection system according to claim 1 , further comprising a control unit that controls the reference image generation step and the image inspection step so that they are performed in parallel.

3. an acquisition unit that acquires a job for forming the image on the recording medium, The image inspection system according to claim 1 , further comprising a control unit that controls the storage device to reserve the first storage unit and the second storage unit based on the acquisition of the job.

4. The image inspection system according to claim 3 , wherein the control unit controls the first storage unit and the second storage unit so as to allocate the first storage unit and the second storage unit for each page of the job.

5. a control unit that controls a storage device to reserve the first storage unit and the second storage unit before the inspection is performed by the image inspection unit; The image inspection system according to claim 1 , wherein when the first storage unit and the second storage unit cannot be secured, the image inspection unit does not perform inspection.

6. The image inspection system according to claim 1 , further comprising a first erasing unit that erases the reference image stored in the first storage unit for each page based on completion of inspection for each page by the image inspection unit.

7. 10. The image inspection system according to claim 1, further comprising a second erasing unit that erases the inspection target image stored in the second storage unit for each page based on completion of inspection for each page by the image inspection unit.

8. 3. The image inspection system according to claim 1, wherein the image inspection unit performs inspection based on the reference image stored in the first storage unit and the inspection target image stored in the second storage unit.

9. an image acquisition unit that acquires a reference image used for inspecting an image formed on a recording medium, the reference image being generated by a reference image generation unit, and an inspection target image generated by reading the image formed on the recording medium; an image inspection unit that inspects the inspection target image based on the reference image; a first storage unit that stores the reference image being generated by the reference image generation unit during generation of the inspection object image; a second storage unit that stores the inspection target image; An image inspection device comprising:

10. (a) generating a reference image to be used for inspecting an image formed on a recording medium; a step (b) of inspecting an inspection target image generated by reading the image formed on the recording medium based on the reference image; a step (c) of storing the reference image being generated in the step (a) in a first storage unit during generation of the inspection object image; (d) storing the inspection object image in a second storage unit; An imaging inspection method comprising:

11. a step (a) of generating a reference image to be used for inspecting an image formed on a recording medium; a step (b) of inspecting an inspection target image generated by reading the image formed on the recording medium based on the reference image; a step (c) of storing the reference image being generated in the step (a) in a first storage unit during generation of the inspection object image; (d) a step of storing the inspection target image in a second storage unit; An image inspection program for causing a computer to execute processing including the above.

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