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

Abstract

The present invention provides an image inspection device, an image inspection method, and an image inspection program that can further shorten the processing time from the generation of a reference image to image inspection compared to conventional technologies. [Solution] The image inspection device 300 includes an image forming unit 330, a reference image generation unit 380, and an image inspection unit 350. The image forming unit 330 forms an image on a recording medium based on acquired image data. The reference image generation unit 380 generates a reference image used for inspecting the image formed on the recording medium based on acquired image data. The image inspection unit 350 inspects the image formed on the recording medium based on the reference image. The image inspection device 300 performs the generation of the reference image and the formation of the image on the recording medium in parallel.

Description

Technical Field

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

Background Art

[0002] Conventionally, the quality of printed matter has been inspected by comparing a previously registered reference image with a read image obtained by reading the printed matter to be inspected. The reference image can be, for example, an image without abnormality in quality among the images obtained by reading the printed matter. Whether there is an abnormality in quality is determined, for example, by an inspector visually checking and determining the presence or absence of an abnormality. As an image forming apparatus having an image inspection unit for inspecting the quality of printed matter, for example, the image forming apparatus described in Patent Document 1 below is known.

[0003] However, as in the image forming apparatus of Patent Document 1, it takes time and effort for an inspector to visually check all pages of the printed matter in order to obtain a reference image. On the other hand, Patent Document 2 below discloses a printed matter inspection apparatus that inspects the quality of printed matter by comparing a manuscript image as a reference image with a read image.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The print inspection apparatus described in Patent Document 2 can save time and effort in creating a reference image by using the original image as the reference image. However, the generation of the reference image (steps S101 to S115 in Figure 6) must be completed before the generation of the inspection image (step S117 in Figure 6) begins. Therefore, there is still a problem that the process from the generation of the reference image (steps S101 to S115 in Figure 6) to the image inspection (steps S117 to S119 in Figure 6) still takes a considerable amount of time.

[0006] The present invention has been made in view of the above circumstances, and aims to provide an image inspection device, an image inspection method, and an image inspection program that can further shorten the time required for processing from the generation of a reference image to image inspection compared to the prior art. [Means for solving the problem]

[0007] The above objectives of the present invention are achieved by the following means.

[0008] (1) An image inspection apparatus comprising: an image forming unit that forms an image on a recording medium based on acquired image data; a reference image generation unit that generates a reference image used for inspecting the image formed on the recording medium based on the acquired image data; and an image inspection unit that inspects the image formed on the recording medium based on the reference image, wherein the generation of the reference image and the formation of the image on the recording medium are performed in parallel.

[0009] (2) The image inspection apparatus according to (1) above, further comprising a document image acquisition unit for acquiring the image data, wherein the reference image generation unit generates a reference image based on the image data.

[0010] (3) A reference image generation step including the generation of a reference image by the reference image generation unit, and the image The image inspection apparatus according to (1) or (2) above, further comprising a control unit that performs in parallel an inspection step including forming the image on a recording medium by a forming unit and inspecting a read image generated by reading the recording medium on which the image has been formed by an image inspection unit.

[0011] (4) The image inspection apparatus according to (1) or (2) above, further comprising a control unit that performs the generation of a reference image by the reference image generation unit and the formation of the image by the image forming unit in the same job.

[0012] (5) The image inspection apparatus according to (1) or (2) above, further comprising a storage device for storing the reference image generated by the reference image generation unit.

[0013] (6) The image inspection apparatus according to (5) above, further comprising a recovery printing unit that performs recovery printing from the page in which an abnormality was detected when an abnormality is detected in the read image as a result of the inspection of the inspection image by the image inspection unit, wherein the image inspection unit performs image inspection using a reference image stored in the storage device during recovery printing.

[0014] (7) The image inspection apparatus according to (2) above, wherein the reference image generation unit and the image forming unit each start generating a reference image and forming an inspection image based on the reception of the image data.

[0015] (8) The image inspection apparatus according to (1) or (2) above, further comprising a recovery printing unit that performs recovery printing if the generation of a reference image by the reference image generation unit is not completed by the time of image inspection by the image inspection unit.

[0016] (9) An image inspection device comprising: an image inspection unit that inspects an image formed on a recording medium by an image forming unit based on image data; and a reference image generation unit that generates a reference image to be used for the inspection of the image formed on the recording medium based on the acquired image data, wherein the generation of the reference image and the inspection of the image are performed in parallel.

[0017] In an image inspection apparatus having an image inspection unit that performs image inspection based on a reference image, a reference image generation unit that generates the reference image, and an image formation unit that forms an inspection image to be inspected by the image inspection unit on a recording medium, an image inspection method including a step of executing in parallel generation of the reference image by the reference image generation unit and formation of the inspection image by the image formation unit.

[0018] In an image inspection apparatus having an image inspection unit that performs image inspection based on a reference image, a reference image generation unit that generates the reference image, and an image formation unit that forms an inspection image to be inspected by the image inspection unit on a recording medium, an image inspection program for causing a computer to execute a procedure of executing in parallel generation of the reference image by the reference image generation unit and formation of the inspection image by the image formation unit.

Advantages of the Invention

[0019] According to the present invention, since generation of the reference image and formation of the inspection image are performed in parallel, the time required for the process from generation of the reference image to image inspection can be shortened.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic block diagram of a printing system according to an embodiment of the present invention. [Figure 2] It is a schematic block diagram illustrating the configuration of the image forming system shown in FIG. 1. [Figure 3] It 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. [Figure 4] It is a flowchart illustrating a processing procedure of an image inspection method by the image forming system shown in FIG. 1. [Figure 5] It is a subroutine flowchart illustrating details of inspection of an inspection image in the flowchart shown in FIG. 4. [Figure 6] It is a schematic diagram showing in time series each process of acquisition of a document image, generation of a reference image, formation of an inspection image, and inspection of the inspection image. [Figure 7] It is a schematic diagram showing in time series each process of acquisition of a document image, generation of a reference image, formation of an inspection image, and inspection of the inspection image when recovery printing is performed.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and duplicate descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0022] <Configuration of the Printing System> 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. 1.

[0023] As shown in FIG. 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 communicably connected to each other through a communication line 400.

[0024] The client terminal 200 can be, for example, a personal computer, a tablet terminal, a smartphone, etc. A printer driver for converting document data into a print job is installed in the client terminal 200. The printer driver generates a print job in a format that the print controller unit 320 (see FIG. 2) of the image forming system 300 can handle, and transmits the print job to the image forming system 300 through the communication line 400. Also, the client terminal 200 includes a display and can display the inspection result (good / defective) of the printed matter, an image of the defective printed matter, etc.

[0025] 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, type of paper (recording medium), size, basis weight, single-sided / double-sided printing, and inspection settings (on / off). By turning on the inspection setting, the user can instruct the image forming system 300 to perform image inspection.

[0026] Communication line 400 may include a LAN (Local Area Network) connecting computers and network devices according to a predetermined standard, or a WAN (Wide Area Network) connecting LANs with dedicated lines. The predetermined standard is, for example, Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), Wi-Fi (Wireless Fidelity), etc.

[0027] Note that the number of each of the above-mentioned components connected to the communication line 400 is not limited to the example shown in Figure 1.

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

[0029] <Configuration of the control unit 310> The control unit 310 includes an image control CPU (Centra 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 storage unit 318, and the like.

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

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

[0032] The image memory 314 is composed of DRAM and includes compressed memory and page memory areas internally, for temporarily storing compressed image data, decompressed image data, etc.

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

[0034] <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, performs processing such as color conversion, screening, and rasterization, and generates a bitmap-formatted original image. The generated original image is transmitted to the control unit 310. The print controller unit 320 functions as an original image acquisition unit.

[0035] The print controller unit 320 comprises 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 interface 326, and the like. The controller control unit 321 comprehensively controls the operation of each part of the print controller unit 320. The controller control unit 321 also receives print jobs from client terminals 200, etc., via the communication interface 326. The communication control unit 325 controls the communication interface 326.

[0036] A received print job includes print data (mainly in PDL format) that forms the basis 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 to convert the print data into page-level bitmap data based on the print settings. The RIP image after rasterization is temporarily stored in the image memory 324. The RIP image in the image memory 324 is temporarily stored in the compressed memory area of ​​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 the original image (image data) via the writing processing unit 317, where printing is performed.

[0037] 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 original image at a predetermined generation timing. The predetermined generation timing may be, for example, when the inspection setting is ON and the original image acquisition unit has acquired the original image. The reference image generation unit 380 generates a reference image based on the reference image generation instruction.

[0038] Ideally, the scanned image generated by reading the inspection image formed on the paper should match the original image in terms of content. However, when scanning the inspection image formed on the paper, errors may occur in the scanned image compared to the original image due to various factors such as variations in the paper transport path, deviations in the scanning position, color reproduction, and differences in paper type. Errors may also occur 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 practical to inspect the inspection image by simply comparing the scanned image with the original image. In this embodiment, various processes are applied to the original image regarding position, resolution, color, etc., to generate a reference image that can be compared with the scanned image, and the system is configured to compare the reference image with the scanned image. This ensures that the comparison with the scanned image is performed appropriately, allowing for accurate inspection of printed materials. Details of the reference image generation process will be described later. In Figure 2, an example is shown where the reference image generation control unit 322 is located in the print controller unit 320, but the reference image generation control unit 322 may also be configured to be located in the control unit 310.

[0039] <Configuration of the image forming unit 330> The image forming unit 330 forms (prints) an image on paper using an electrophotographic method that includes the steps of charging, exposure, development, transfer, and fixing, according to the instructions of the control unit 310. In this embodiment, the image forming unit 330 forms an inspection image on the paper according to the image forming conditions set based on the print settings, which is to be inspected by the image inspection unit 350. The image forming unit 330 includes a printer control unit 331 and an exposure unit 332, etc. The printer control unit 331 is connected to the image control CPU 311 by serial communication and accepts control from the image control CPU 311. The printer control unit 331 drives the LD (Laser Diode) of the exposure unit 332 by a signal from the writing processing unit 317 to form an electrostatic latent image corresponding to the original image on the photoreceptor (not shown). The toner image formed on the photoreceptor is developed through the development process and transferred onto the paper supplied from the paper feeding unit 370. The unfixed toner image on the paper is then fixed by heating and pressurizing. The paper on which the toner image has been fixed is transported to the image reading unit 340.

[0040] Furthermore, the image forming unit 330 is equipped with a print sheet output device that separates and outputs (purges) sheets on which an abnormal inspection image has been detected by the image inspection unit 350 (waste paper) from sheets on which a normal inspection image has been formed.

[0041] <Configuration of the image reading unit 340> The image reading unit 340 includes 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, according to the reading instructions from the control unit 310. The scanner control unit 342 outputs the read image, which is the inspection image formed on the paper, to the control unit 310.

[0042] <Configuration of the Image Inspection Unit 350> The image inspection unit 350 performs image inspection based on a reference image. More specifically, the image inspection unit 350 acquires a reference image and a read image, and inspects the inspection image formed on the paper by comparing the reference image and the read image page by page.

[0043] 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 (not shown), RAM, ROM, and auxiliary storage device. The function of inspecting the inspection image is realized by the CPU executing an image inspection program. The image inspection control unit 351 calculates, for example, the difference (error) of pixel values ​​between a reference image and a read image for each page, and determines whether the inspection image is good or bad according to the size of the difference. The difference calculation can be performed for each page, each object, or each region. For example, when the difference is calculated for each page, if the total difference of pixels within a page is less than a specified value, an inspection result of "good" is output, and if the total difference is equal to or greater than the specified value, an inspection result of "bad" is output. Also, when the difference is calculated for each object or region, the system can be configured to output an inspection result of "good" or "bad" according to the total difference of pixel values ​​within the selected object or region.

[0044] The control unit 310 determines that the printed material is a good product if the inspection result of the inspection image is "good," and determines that the printed material is a defective product if the inspection result of the inspection image is "poor."

[0045] <Configuration of the operation display unit 360> The operation display unit 360 includes a touch panel display 361, an operation control unit 362, and hard keys such as a numeric keypad, start button, stop button, etc. The touch panel display includes, for example, a touch sensor and an LCD (Liquid Crystal Display) located behind the touch sensor. The operation control unit 362 receives 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 by the user (e.g., turning inspection settings on / off) and instructions (e.g., instructions to start printing). The operation display unit 360 is also used for outputting (displaying) the status of the image forming system 300, the inspection results of printed materials (good / defective), images of defective printed materials, etc.

[0046] <Configuration of the paper feeding unit 370> The paper feeding unit 370 is equipped with at least one large-capacity paper tray and supplies paper to the image forming unit 330 one sheet at a time.

[0047] <Configuration of the reference image generation unit 380> The reference image generation unit 380 generates a reference image based on the original image acquired by the original image acquisition unit and outputs it to the control unit 310. The reference image generation unit 380 may be implemented by having a separate CPU (not shown) execute an image inspection program, distinct from the image control CPU 311. This configuration allows for the parallel execution of reference image generation and inspection image formation and inspection. Alternatively, if the image control CPU 311 is a multi-core CPU, the reference image generation unit 380 may be assigned to a separate core from the inspection image formation and inspection processes, and the reference image generation and inspection image formation and inspection may be executed in parallel by separate cores.

[0048] Conventionally, the generation of reference images and the formation and inspection of inspection images were performed by the same CPU. Therefore, the CPU performed the formation and inspection of inspection images only after the generation of reference images was completed for each page, making it impossible to perform the generation of reference images and the formation and inspection of inspection images in parallel. In this embodiment, the generation of reference images and the formation and inspection of inspection images are performed by separate CPUs, so the generation of reference images and the formation and inspection of inspection images can be performed in parallel.

[0049] Furthermore, if the source image is complex, the computational load for generating the reference image may increase significantly. By having a separate CPU handle the generation of the reference image, the computational load on the image control CPU 311 can be reduced.

[0050] <Configuration of storage device 390> The storage device 390 stores the reference image generated by the reference image generation unit 380. When the control unit 310 reprints the original image, it uses the reference image stored in the storage device 390, eliminating the need to generate the reference image again. Therefore, the time required to generate the reference image can be saved.

[0051] <Overview of the control operation of the control unit 310 and the print controller unit 320> Figure 3 is a block diagram illustrating the general control operation of the control unit 310 and print controller unit 320 shown in Figure 2.

[0052] First, the control unit 310 receives the original image and job information from the original image acquisition unit (print controller unit 320) ((1) Image Input). The original image is a RIP image obtained by rasterizing the print data.

[0053] When the reference image generation unit 380 receives a reference image generation instruction from the reference image generation control unit 322 ((2)-1 Reference Image Generation Instruction), it generates a reference image based on the original image acquired by the original image acquisition unit and outputs it to the control unit 310. The control unit 310 stores the reference image in the page memory 1.

[0054] As described above, the reference image generation unit 380 generates a reference image by performing various processes on the original image regarding its position, resolution, color, etc. For example, the reference image generation unit 380 can extract positional information of the content portion from the original image and add or embed this positional information into the reference image so that the content portions of the reference image and the scanned image can be compared. In other words, the reference image generated by the reference image generation unit 380 has alignment information for aligning the reference image and the scanned image when performing image inspection based on the reference image. This alignment information includes image contour information and edge information. Furthermore, the reference image generated by the reference image generation unit 380 has area information regarding inspection areas and inspection exclusion areas used when performing image inspection based on the reference image. In addition, the reference image generation unit 380 can generate a reference image by adjusting the resolution of the original image to match the resolution of the scanner of the image reading unit 340. Furthermore, the reference image generation unit 380 can generate a reference image by converting the color space of the original image to match the color space (for example, RGB) used by the scanner of the image reading unit 340.

[0055] Furthermore, when the control unit 310 receives a document image from the document image acquisition unit, it instructs the image forming unit 330 to form an image and outputs the document image stored in 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 the paper based on the document 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.

[0056] When the reference image generation unit 380 has finished generating the reference image, it notifies the reference image generation control unit 322 that the reference image generation is complete ((3)-1 Reference image generation complete). Also, when the image forming unit 330 has finished forming the image on the paper, it notifies the control unit 310 that the output is complete ((3)-2 Output complete). The storage device 390 saves the generated reference image ((4)-1 Reference image save).

[0057] Furthermore, as soon as the control unit 310 receives notification of output completion, it 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 has been formed and outputs the read image of the paper to the control unit 310. The control unit 310 saves the read image in the page memory 2. When the image reading unit 340 has finished reading the paper, it notifies that the image reading is complete ((5)-2 Image Reading Complete).

[0058] 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 acquires a reference image and a read image from page memory 1 and page memory 2, respectively, and inspects the inspection image by comparing the reference image and the read image. The image inspection unit 350 then outputs the inspection result of the inspection image to the control unit 310 ((7)-2 Image Inspection Result).

[0059] The control unit 310, in response to user instructions, controls the display of the inspection results (good / defective) of the printed material based on the inspection results of the inspection images, on the display of the operation display unit 360 or the client terminal 200.

[0060] <Image inspection method using image forming system 300> Figure 4 is a flowchart illustrating the processing steps of the image inspection method using the image forming system 300 shown in Figure 1. Figure 5 is a subroutine flowchart illustrating the details of the inspection of the inspection image in the flowchart shown in Figure 4. The processes shown in Figures 4 and 5 are realized by the image control CPU 311 executing the image inspection program. Figure 6 is a schematic diagram showing the processes of acquiring the original image, generating the reference image, forming the inspection image, and inspecting the inspection image in chronological order.

[0061] As shown in Figure 4, first, the control unit 310 acquires the 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, Figure 6 illustrates the case where the original image is received sequentially from the first page to the eighth page. In Figure 6 and Figure 7, "1P" represents the first page (and so on for "2P," etc.). Furthermore, "print preparation" in the formation of the inspection image includes initial settings and preparations of each part in the image forming unit 330 according to the image forming conditions (for example, warming up the fixing unit).

[0062] Next, the control unit 310 saves the original image (step S102). When a print job is started, the control unit 310 saves the original image acquired from the original image acquisition unit to the page memory 1 one page at a time.

[0063] Next, the reference image generation control unit 322 controls the generation of reference images used for inspecting the inspection images. The reference image generation unit 380 generates reference images according to the instructions of the reference image generation control unit 322 (step S103). For example, if the first page of the original image has been acquired and stored in page memory 1, the reference image generation control unit 322 controls the reference image generation unit 380 to generate a reference image based on the first page of the original image. The reference image generation unit 380 generates a reference image based on the first page of the original image. A reference image is similarly generated for the second page of the original image.

[0064] Next, the storage device 390 stores the reference image generated by the reference image generation unit 380 (step S104). For example, the storage device 390 stores the first and second pages of the original image. Also, in this embodiment, as shown in Figure 6, in parallel with the processing in steps S103 and S104, the control unit 310 controls the image forming unit 330 to form an inspection image on the paper based on the original image and job information received from the original image acquisition unit. For example, the control unit 310 prepares for printing and forms an inspection image on the paper for the first page of the original image. The image forming unit 330 is controlled to form an image. The image forming unit 330 forms an inspection image on the paper for the first page of the original image according to the instructions of the control unit 310 (step S105). After the inspection image for the first page of the original image is formed, an inspection image is similarly formed on the paper for the second page of the original image.

[0065] Next, the image inspection unit 350 determines whether a reference image has been generated for each page of the acquired original 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 has not been generated for the original image (page 1) that will be the basis for the inspection image inspected in step S107, the unit waits until a reference image for this original image (page 1) is generated.

[0066] As shown in Figure 6, the generation of a reference image by the reference image generation unit 380 and the formation of an inspection image by the image forming unit 330, as well as the inspection of the inspection image, are performed in parallel. As a result, the image forming system 300 can further reduce the time required for processing from the generation of a reference image to image inspection compared to conventional technology.

[0067] [Generating reference images and forming inspection images on paper in parallel] For example, in the example shown in the figure, the generation of reference images for page 1 (1P) and page 2 (2P) and the preparation for printing are performed in parallel, and the generation of the reference image for page 3 (3P) and the formation of the first half of the inspection image for page 1 (1P) are performed in parallel. Then, the generation of the reference image for page 4 (4P) and the formation of the second half of the inspection image for page 1 (1P) are performed in parallel. Note that although the figure shows the generation of the reference image for page 3 (3P) and the formation of the inspection image for page 1 (1P) starting simultaneously, this is not the only option. The formation of the inspection image for page 1 (1P) can start at an appropriate time after the preparation for printing is complete, and the generation of the reference image for page 3 (3P) can start at an appropriate time after the generation of the reference image for page 2 (2P). The timing for starting the generation of reference images and inspection images is the same for subsequent pages.

[0068] [Generating reference images, forming inspection images on paper, and inspecting the inspection images in parallel] Subsequently, the generation of the reference image on page 5 (5P), the formation of the examination image on page 2 (2P), and the examination of the examination image on page 1 are performed in parallel.

[0069] As shown in Figure 5, in the process of inspecting the inspection image, the inspection image formed on the paper is read by the image reading unit 340 (step S201), and the inspection image is inspected by comparing the reference image with the read image by the image inspection unit 350 (step S202).

[0070] The control unit 310 repeats the process in steps S101 to S107 for all pages (from the first page to the last nth page) until the inspection of the inspection images is completed (step S108).

[0071] In this embodiment, based on the reception of the original image (starting from the reception of the original image), a reference image is generated, and when the paper is ready for printing, an inspection image is formed 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 image inspection can be shortened. As a result, the productivity of printed materials is improved.

[0072] <Print Job> As described above, the image forming system 300 receives a print job and performs a check of the job information. When the setting is ON, the generation of the reference image and the formation of the inspection image are performed in parallel. The control unit 310 and the print controller unit 320 control the process so that the generation of the reference image by the reference image generation unit 380 and the formation of the inspection image by the image formation unit 330 are performed in parallel for a single (identical) print job.

[0073] On the other hand, the image forming system 300 may implement the generation of a reference image, the formation of an inspection image, and the inspection through 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 by the image inspection unit 350 of the read image generated by reading the paper on which the inspection image has been 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 be configured to execute the reference image generation process and the inspection process in parallel.

[0074] <Recovery Printing> Figure 7 is a schematic diagram illustrating the time-series process of acquiring the original image, generating a reference image, forming an inspection image, and inspecting the inspection image when recovery printing is performed.

[0075] 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 performs reprinting (recovery printing) from the page of the original 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 if the inspection image is found to be defective as a result of inspection by the image inspection unit 350. The control unit 310 purges the paper on which the inspection image with the detected abnormality was formed as waste paper to the outside of the image forming system 300.

[0076] Furthermore, generally speaking, the more complex the original image, the longer it takes for the reference image generation unit 380 to generate the reference image. For example, Figure 7 illustrates that the second page of the original image is complex, and therefore it takes time to generate the second page of the reference image. The recovery printing unit performs recovery printing if the generation of the reference image is not completed by the time of inspection of the corresponding inspection image. For example, in the example shown in Figure 7, the recovery printing unit waits for the generation of the reference image to be completed before performing recovery printing of the second page of the original image (formation of the second page of the inspection image) because the generation of the second page of the reference image has not been 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 with the uninspected inspection image from being mixed with the paper with the normal inspection image.

[0077] Furthermore, the image inspection unit 350 can perform image inspection using the reference image stored in the storage device 390 during recovery printing. This eliminates the need for the reference image generation unit 380 to generate the reference image again, thus saving time required for generating the reference image.

[0078] Furthermore, when performing a recovery print, the original image saved in page memory 1 in step S102 of Figure 4 can be configured to be saved in storage device 390. By using the original image saved in storage device 390, the processes of steps S101 and S102 become unnecessary, in addition to the processes of generating and saving the reference image (steps S103 and S104). Therefore, the control unit 310 and the print controller unit 320 control the print job to execute only the processes of forming and inspecting the inspection image. This reduces the time required from the start of the print job to the completion of inspection of the printed material. This improves the productivity of printed materials.

[0079] As described above, the image inspection apparatus, image inspection method, and image inspection program have been explained in the embodiments. However, it goes without saying that the present invention can be appropriately added to, modified, and omitted by those skilled in the art within the scope of its technical concept.

[0080] For example, the above-described embodiment described a case in which an original image is generated based on a print job, but the present invention is not limited to such a case. The image forming unit 330 may have an image reading device 333 (see Figure 1) that reads an original document prepared by the user, and may be configured to generate an original image based on the image generated by reading the original document with the image reading device 333. The image reading device 333, for example, reads an original document that has been transported to a predetermined reading position by an automatic document transport device using a scanner and generates image data.

[0081] Furthermore, the image inspection program may be provided on a computer-readable recording medium such as a USB memory stick, flexible disk, or CD-ROM, or it may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to memory or storage and stored therein. This inspection program may also be provided, for example, as a standalone application software, or it may be incorporated into the software of each device as a function of a server.

[0082] Furthermore, in the embodiment, some or all of the processing performed by the inspection program may be replaced and executed by hardware such as circuits. [Explanation of Symbols]

[0083] 100 printing systems, 200 client terminals, 300 image forming systems, 310 Control unit, 311 Image control CPU, 312 DRAM control IC, 313 memory, 314 Image memory (DRAM), 315 Compression / Decompression IC, 316 Reading processing unit, 317 Writing processing unit, 318 Memory section, 320 Print Controller Section, 321 Controller control unit, 322 Reference image generation control unit, 323 DRAM control IC, 324 Image memory (DRAM), 325 Communication control unit, 326 Communication I / F, 330 Image forming unit, 331 Printer control unit, 332 Exposure section, 333 Image reading device, 340 Image reading unit, 341 Scanners, 342 Scanner control unit, 350 Image Inspection Department, 351 Image inspection control unit, 360 operation display section, 361 LCD / touch sensor, 362 Operation control unit, 370 Paper feed section, 380 Reference image generation unit, 390 storage device, 400 communication lines.

Claims

1. An image forming unit that forms an image on a recording medium based on acquired image data, A reference image generation unit generates a reference image used for inspecting the image formed on the recording medium, based on the acquired image data, The system includes an image inspection unit that inspects an image formed on the recording medium based on the aforementioned reference image, An image inspection apparatus that generates the aforementioned reference image and forms an image on the recording medium in parallel.

2. The system further includes a document image acquisition unit that acquires the aforementioned image data, The image inspection apparatus according to claim 1, wherein the reference image generation unit generates a reference image based on the image data.

3. The image inspection apparatus according to claim 1 or 2, further comprising a control unit that performs in parallel a reference image generation step including the generation of a reference image by the reference image generation unit, and an inspection step including the formation of the image on a recording medium by the image forming unit, and the inspection of a read image generated by reading the recording medium on which the image has been formed by the image inspection unit.

4. The image inspection apparatus according to claim 1 or 2, further comprising a control unit that performs the generation of a reference image by the reference image generation unit and the formation of the image by the image forming unit in the same job.

5. The image inspection apparatus according to claim 1 or 2, further comprising a storage device for storing the reference image generated by the reference image generation unit.

6. The system further includes a recovery printing unit that, if an abnormality is detected in the read image as a result of the inspection of the inspection image by the aforementioned image inspection unit, performs recovery printing from the page in which the abnormality was detected. The image inspection device according to claim 5, wherein the image inspection unit performs image inspection using a reference image stored in the storage device during recovery printing.

7. The image inspection apparatus according to claim 2, wherein the reference image generation unit and the image forming unit each start generating a reference image and forming an inspection image based on the reception of the image data.

8. The image inspection apparatus according to claim 1 or 2, further comprising a recovery printing unit that performs recovery printing if the generation of a reference image by the reference image generation unit is not completed by the time of image inspection by the image inspection unit.

9. An image inspection unit that inspects the image formed on the recording medium by the image forming unit based on image data, The system includes a reference image generation unit that generates a reference image used for inspecting the image formed on the recording medium, based on the acquired image data, An image inspection device that generates the aforementioned reference image and inspects the aforementioned image in parallel.

10. The image inspection department performs image inspections based on reference images, A reference image generation unit that generates the aforementioned reference image, An image inspection apparatus having an image forming unit that forms an inspection image on a recording medium, wherein the image inspection unit performs the inspection, An image inspection method comprising the steps of generating a reference image by the reference image generation unit and forming an inspection image by the image forming unit in parallel.

11. The image inspection department performs image inspections based on reference images, A reference image generation unit that generates the aforementioned reference image, An image inspection apparatus having an image forming unit that forms an inspection image on a recording medium, wherein the image inspection unit performs the inspection, An image inspection program that causes a computer to perform a procedure in which the reference image generation unit generates a reference image and the image forming unit forms an inspection image in parallel.

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