JP2015141093A - Image inspection apparatus, image forming system, and image inspection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for inspecting an output image by comparing a read image with an inspection image, configured to properly determine whether to store a result of inspection.SOLUTION: An image inspection apparatus includes: a defect determination section 432 which acquires a difference image indicating a difference between a master image and a read image, and an inspection result obtained by determining a defect of the read image; a controller communication section 433 which acquires printing condition information indicating a condition in forming an image to be inspected, which is an original of the read image; a storage processing section 434 which stores the difference image, the inspection result, and the printing condition information, in association with each other, on a storage medium, as storage information to be stored by inspecting the image; an evaluation value calculation section 438 which calculates an evaluation value indicating the importance of the storage information, on the basis of the printing condition information and the inspection result; a deletion determination section 439 which determines storage information to be deleted, on the basis of the calculated evaluation value; and a deletion processing section 440 which deletes the storage information to be deleted.

Description

  The present invention relates to an image inspection apparatus, an image forming system, and an image inspection program, and more particularly to storage of information indicating inspection results.

  Conventionally, inspection of printed matter has been performed manually, but in recent years, an apparatus for performing inspection has been used as post-processing of offset printing. In such an inspection apparatus, a master image serving as a reference is generated by manually selecting and reading a non-defective product from the read image of the printed matter, and a corresponding portion of the master image and the read image of the printed matter to be inspected. And the defect of the printed matter is discriminated by the degree of these differences.

  However, plateless printing devices such as electrophotography, which have become popular in recent years, are good at printing a small number of parts, and there are many cases where the content of printing on each page differs, such as variable printing, and a master image is generated from printed matter like an offset printer. In comparison, it is inefficient. In order to cope with this problem, it is conceivable to generate a master image from print data. Thereby, it can respond to variable printing efficiently (for example, refer to patent documents 1).

  In such a comparative inspection of images, information on the inspection result may be stored and used for later analysis, re-determination of defects, and the like. It is sufficient that all data can be stored regardless of the presence or absence of defects. However, since the storage capacity is limited, it is necessary to select data to be stored. As such a method, a method has been proposed in which deletion is determined based on defect type, occurrence frequency, size, storage area capacity, defect importance, etc., for data in which defects are detected (for example, , See Patent Document 2).

  According to the method disclosed in Patent Document 2, it is possible to select data to be stored for data determined as a defect. However, whether or not a defect is determined varies depending on the threshold setting. Therefore, it is not sufficient to select data only for data determined to be defective based on a certain threshold.

  Further, the state of the print result is determined based on a printer that is an apparatus that outputs an image to a recording medium such as paper and the content of the output image. Therefore, the possibility that a defect will occur in the output image is determined based on conditions such as the state of the apparatus and the content of the image. The threshold is not determined, and the determination is performed by uniformly applying the set threshold.

  As a result, even if the data has a high degree of defect with respect to conditions such as the state of the apparatus and the content of the image, data that is not determined to be defective based on a certain threshold is not subject to storage, and the threshold is later It is impossible to make a defect determination again after changing.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to suitably perform determination of storage of inspection results in a system that inspects the results of image formation output by comparing a read image with an inspection image. .

  In order to solve the above problems, an aspect of the present invention is an image inspection apparatus that inspects a read image obtained by reading an image formed and output on a recording medium, and the image formed and output is read. A read image acquisition unit that acquires the read image generated in this manner, and a difference between the read image and the inspection image generated based on the information of the image to be imaged and output to inspect the read image An inspection result acquisition unit that acquires an inspection result that is a result of determining a defect in the read image based on the difference image and the difference image, and an image that is an original image of the read image that is an inspection target is output A print condition information acquisition unit that acquires print condition information indicating the conditions of the image, the difference image, the inspection result, and the print condition information are associated with each other in the storage medium as saved information that is stored by image inspection A storage processing unit for storing, an evaluation value calculation unit for calculating an evaluation value indicating the importance of the stored information based on the printing condition information and the inspection result, and a storage medium based on the calculated evaluation value. It includes a deletion determination unit that determines storage information to be deleted, and a deletion processing unit that deletes the determined storage information to be deleted.

  According to the present invention, in a system that inspects a result of an image formation output by comparing a read image with an inspection image, it is possible to suitably make a determination to save the inspection result.

1 is a diagram illustrating a configuration of an image forming system including an inspection apparatus according to an embodiment of the present invention. It is a block diagram which shows the hardware constitutions of the test | inspection apparatus which concerns on embodiment of this invention. It is a block diagram which shows the function structure of DFE which concerns on embodiment of this invention, an engine controller, a print engine, and an inspection apparatus. It is a figure which shows the printing condition information which concerns on embodiment of this invention. It is a figure which shows the aspect of the comparison test | inspection which concerns on embodiment of this invention. 1 is a diagram illustrating a configuration of a print engine according to an embodiment of the present invention. It is a block diagram which shows the function structure of the master image process part which concerns on embodiment of this invention. It is a figure which shows the function structure of the test | inspection control part which concerns on embodiment of this invention. It is a flowchart which shows the test | inspection operation | movement which concerns on embodiment of this invention. It is a figure which shows the example of the test result information which concerns on embodiment of this invention. 4 is a flowchart illustrating a refresh operation according to an embodiment of the present invention. It is a figure which shows the weighting coefficient table classified by operation time which concerns on embodiment of this invention. It is a figure which shows the weight coefficient table classified by toner usage which concerns on embodiment of this invention. It is a figure which shows the weighting coefficient table classified by paper size which concerns on embodiment of this invention. It is a figure which shows the weighting coefficient table classified by sheet thickness which concerns on embodiment of this invention. It is a figure which shows the weighting coefficient table classified by paper type which concerns on embodiment of this invention. It is a figure which shows the defect occurrence rate table according to operation time which concerns on embodiment of this invention. It is a figure which shows the weighting coefficient table classified by defect number which concerns on embodiment of this invention. It is a figure which shows the weighting coefficient table classified by defect type which concerns on embodiment of this invention. It is a figure which shows the defect occurrence rate table according to defect type which concerns on embodiment of this invention. It is a figure which shows the production | generation aspect of the evaluation value which concerns on embodiment of this invention. It is a figure which shows the aspect of the frequency distribution analysis of the evaluation value which concerns on embodiment of this invention. It is a figure which shows the significance of the item contained in the printing condition information which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, in an image inspection system including an inspection device that inspects an output result by comparing a read image obtained by reading an output result by image formation output with a master image, a function of storing all information on the inspection result is provided. A characteristic process for determining whether to delete the information of the stored examination result will be described. FIG. 1 is a diagram illustrating an overall configuration of an image forming system according to the present embodiment.

  As shown in FIG. 1, the image forming system according to the present embodiment includes a DFE (Digital Front End) 1, an engine controller 2, a print engine 3, an inspection device 4, and an interface terminal 5. The DFE 1 is an image processing apparatus that generates image data to be printed based on a received print job, that is, bitmap data that is an output target image, and outputs the generated bitmap data to the engine controller 2.

  The engine controller 2 controls the print engine 3 based on the bitmap data received from the DFE 1 to execute image formation output. The engine controller 2 transmits the bitmap data received from the DFE 1 to the inspection apparatus 4 as information that is the basis of an inspection image for reference when the inspection apparatus 4 inspects the result of the image formation output by the print engine 3. To do.

  In addition, when the engine controller 2 according to the present embodiment controls the print engine 3 to execute image formation output, the inspection apparatus receives print condition information including information about an output target image and information about the state of the print engine 3. 4 is output. The processing of the inspection apparatus 4 based on the printing condition information is one of the gist according to the present embodiment.

  The print engine 3 is an image forming apparatus that executes image formation output on a sheet as a recording medium based on bitmap data in accordance with control of the engine controller 2. As the recording medium, in addition to the above-described paper, a sheet-like material such as a film or plastic can be used as long as it is an object for image formation output.

  The inspection device 4 generates a master image based on the bitmap data input from the engine controller 2. The inspection device 4 is an image inspection device that inspects an output result by comparing a read image generated by reading a sheet output from the print engine 3 with a reading device with the generated master image.

  The inspection apparatus 4 according to the present embodiment stores all the information indicating the result of the image inspection based on the comparison between the read image and the master image described above in a storage medium in principle. One of the gist according to the present embodiment is to refer to the print condition information described above in the stored information refresh process executed when the remaining free space of the storage medium is equal to or less than a predetermined threshold. is there.

  Further, when the inspection apparatus 4 determines that the output result is defective by comparing the master image and the read image, the inspection apparatus 4 notifies the engine controller 2 of information indicating a page that is recognized as a defect. Thereby, reprint control of the defective page is executed by the engine controller 2.

  The interface terminal 5 is an information processing terminal for displaying a GUI (Graphical User Interface) for confirming a defect determination result by the inspection apparatus 4 and a GUI for setting parameters in the inspection, and is a PC (Personal Computer). This is realized by a general information processing terminal such as.

  Here, hardware constituting the DFE 1, the engine controller 2, the print engine 3, the inspection apparatus 4, and the interface terminal 5 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating a hardware configuration of the inspection apparatus 4 according to the present embodiment. In FIG. 2, the hardware configuration of the inspection apparatus 4 is shown, but the same applies to other apparatuses.

  As shown in FIG. 2, the inspection apparatus 4 according to the present embodiment has the same configuration as an information processing apparatus such as a general PC (Personal Computer) or a server. That is, the inspection apparatus 4 according to the present embodiment includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, an HDD (Hard Disk Drive) 40, and an I / F 50. Connected through. Further, an LCD (Liquid Crystal Display) 60, an operation unit 70, and a dedicated device 80 are connected to the I / F 50.

  The CPU 10 is a calculation means and controls the operation of the entire inspection apparatus 4. The RAM 20 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 10 processes information. The ROM 30 is a read-only nonvolatile storage medium and stores a program such as firmware. The HDD 40 is a non-volatile storage medium that can read and write information, and stores an OS (Operating System), various control programs, application programs, and the like.

  The I / F 50 connects and controls the bus 90 and various hardware and networks. The LCD 60 is a visual user interface for the user to check the state of the inspection apparatus 4. The operation unit 70 is a user interface such as a keyboard and a mouse for the user to input information to the inspection apparatus 4.

  The dedicated device 80 is hardware for realizing a dedicated function in the engine controller 2, the print engine 3, and the inspection apparatus 4. In the case of the print engine 3, A plotter device that executes image formation output on a paper surface. Further, the engine controller 2 and the inspection device 4 are dedicated arithmetic devices for performing image processing at high speed. Such an arithmetic unit is configured as an ASIC (Application Specific Integrated Circuit), for example. Also included is a reading device that reads an image output on paper.

  In such a hardware configuration, the software control unit is configured by the CPU 10 performing calculations in accordance with a program stored in the ROM 30 or a program read to the RAM 20 from a recording medium such as the HDD 40 or an optical disk (not shown). The A functional block that realizes the functions of the DFE 1, the engine controller 2, the print engine 3, the inspection apparatus 4, and the interface terminal 5 according to the present embodiment is configured by a combination of the software control unit configured as described above and hardware. Is done.

  FIG. 3 is a block diagram illustrating functional configurations of the DFE 1, the engine controller 2, the print engine 3, and the inspection device 4 according to the present embodiment. In FIG. 3, data transmission / reception is indicated by a solid line, and the flow of paper is indicated by a broken line. As illustrated in FIG. 3, the DFE 1 according to the present embodiment includes a job information processing unit 101 and a RIP processing unit 102. The engine controller 2 includes a data acquisition unit 201, an engine control unit 202, and a bitmap transmission unit 203. The print engine 3 includes a print processing unit 301. The inspection device 4 includes a reading device 400, a read image acquisition unit 401, a master image processing unit 402, an inspection control unit 403, and a comparative inspection unit 404.

  The job information processing unit 101 executes image formation output based on a print job input from outside the DFE 1 via a network or a print job generated based on image data stored in the DFE 1 by an operator's operation. Control. When executing the image formation output, the job information processing unit 101 causes the RIP processing unit 102 to generate bitmap data based on the image data included in the print job.

  The RIP processing unit 102 generates bitmap data for the print engine 3 to execute image formation output based on the image data included in the print job, under the control of the job information processing unit 101. Bitmap data is information of each pixel constituting an image to be imaged and output. The print engine 3 according to the present embodiment executes image formation output based on binary images of CMYK (Cyan, Magenta, Yellow, blackK). On the other hand, generally, image data included in a print job is a multi-valued image in which one pixel is expressed by multi-gradation such as 256 gradations. Therefore, the RIP processing unit 102 converts the image data included in the print job from a multi-valued image to a small-valued image, generates CMYK binary data for each color, and transmits it to the engine controller 2.

  The data acquisition unit 201 acquires bitmap data input from the DFE 1 and operates the engine control unit 202 and the bitmap transmission unit 203, respectively. The engine control unit 202 causes the print engine 3 to execute image formation output based on the bitmap data transferred from the data acquisition unit 201. The bitmap transmission unit 203 transmits the bitmap data acquired by the data acquisition unit 201 to the inspection apparatus 4 for generating a master image.

  Furthermore, when the engine control unit 202 according to the present embodiment causes the print engine 3 to execute image formation output based on the bitmap data input from the data acquisition unit, the above-described print condition information is generated and the inspection apparatus 4 to send. With reference to FIG. 4, the printing condition information according to the present embodiment will be described.

  As shown in FIG. 4, the printing condition information according to the present embodiment includes information on “inspection result information identification ID”, “operation time”, “toner usage”, and “paper attribute”. The “inspection result information identification ID” is identification information for identifying the inspection result information corresponding to the printing condition information, and corresponds to the generation of the inspection result information on the inspection apparatus 4 side that has received the printing condition information. Is granted.

  “Operating time” indicates the operating time of the print engine 3. “Toner use amount” is information indicating the toner use amount used in the image forming output based on the target bitmap data, and is indicated by percentage for each color of CMYK as shown in FIG. As described above, the bitmap data according to the present embodiment is CMYK binary information. Therefore, the engine control unit 202 calculates the toner usage by calculating the ratio of the number of colored pixels of each color of CMYK to the total number of pixels based on the target bitmap data.

  “Paper attribute” is information about a sheet that is a recording medium to be subjected to image formation output, and includes information of “size”, “thickness”, and “type” as shown in FIG. As described above, the printing condition information according to the present embodiment includes items relating to the state of the print engine 3 at the time of image formation output and items relating to the contents of the image formation output.

  FIG. 23 is a diagram showing the significance of each item of the printing condition information shown in FIG. As shown in FIG. 23, a defect may easily occur in a specific operating time period such as immediately after system startup, during continuous operation, or immediately after returning from long-time paper feeding. “Operating time” is an item for that purpose.

  In addition, a defect may easily occur when an image different from the average toner usage, such as an image with many solid areas or an image with many plain areas, is output. “Toner consumption” is an item for that purpose. In addition, when the paper size is larger than the standard paper size, defects may easily occur. “Paper size” is an item for that purpose.

  In addition, a defect may easily occur in a specific paper type such as thin paper or thick paper. “Paper thickness” is an item for that purpose. In addition, defects may easily occur on paper with poor toner fixability, such as coated paper. “Paper type” is an item for that purpose.

  The print processing unit 301 is an image forming unit that acquires bitmap data input from the engine controller 2, executes image formation output on printing paper, and outputs printed paper. The print processing unit 301 according to the present embodiment is realized by a general electrophotographic image forming mechanism, but other image forming mechanisms such as an ink jet method can also be used.

  The reading device 400 is an image reading unit that reads an image formed on a sheet of printing paper that has been printed and output by the print processing unit 301 and outputs read data. The reading device 400 is, for example, a line scanner installed in a conveyance path inside the inspection device 4 for printing paper output by the print processing unit 301. The scanning device 400 scans the paper surface of the printing paper to be conveyed on the paper surface. Read the formed image.

  The read image generated by the reading device 400 is an inspection target by the inspection device 4. Since the read image is an image generated by reading the paper surface of the paper output by the image forming output, the read image is an image indicating the output result. The read image acquisition unit 401 acquires information of a read image generated by reading the paper surface of the printing paper by the reading device 400. The information of the read image acquired by the read image acquisition unit 401 is input to the comparison inspection unit 404 for comparison inspection. Note that the input of the read image to the comparison inspection unit 404 is executed under the control of the inspection control unit 403. At that time, the inspection control unit 403 obtains the read image and inputs it to the comparison inspection unit 404.

  The master image processing unit 402 acquires the bitmap data input from the engine controller 2 as described above, and generates a master image that is an inspection image for comparison with the inspection target image. That is, the master image processing unit 402 functions as an inspection image generation unit that generates a master image, which is an inspection image for inspecting the read image, based on the output target image. The master image generation processing by the master image processing unit 402 will be described in detail later.

  The inspection control unit 403 is a control unit that controls the operation of the entire inspection apparatus 4, and each component included in the inspection apparatus 4 operates according to the control of the inspection control unit 403. The comparison inspection unit 404 compares the read image input from the read image acquisition unit 401 with the master image generated by the master image processing unit 402, and determines whether or not the intended image formation output is being executed. . The comparison inspection unit 404 is configured by the ASIC described above in order to quickly process a huge amount of calculation. In the present embodiment, the inspection control unit 403 functions as an image inspection unit by controlling the comparative inspection unit 404 and also functions as an inspection result acquisition unit that acquires an inspection result by the comparative inspection unit 404.

  In the comparison inspection unit 404, as described above, the 200 dpi read image and the master image expressed in 8 bits for each RGB color are compared for each corresponding pixel, and the difference value between the 8 bit pixel values for each RGB color described above for each pixel. Is calculated. Based on the magnitude relationship between the difference value thus calculated and the threshold value, the inspection control unit 403 determines the presence or absence of a defect in the read image. That is, the inspection control unit 403 functions as an image inspection unit by controlling each unit included in the inspection apparatus 4.

  When comparing the read image with the master image, the comparison inspection unit 404 superimposes the master image divided for each predetermined range on the read image corresponding to the divided range, as shown in FIG. The pixel value of the pixel, that is, the density difference is calculated. Such processing is realized by the inspection control unit 403 acquiring images in the overlapping range from the master image and the read image and inputting them to the comparison inspection unit 404.

  Further, the inspection control unit 403 shifts the position where the divided range is superimposed on the read image vertically, that is, while shifting the range of the image acquired from the read image vertically and horizontally, the total difference value calculated is calculated. The smallest position is determined as an accurate overlay position, and the difference value of each pixel calculated at that time is adopted as a comparison result. Therefore, the comparison inspection unit 404 can output the vertical and horizontal deviation amounts when determined as the alignment position together with the difference value of each pixel.

  As shown in FIG. 5, each square divided on the grid is a predetermined range in which the difference values of the pixels described above are summed. Further, the size of each division range shown in FIG. 5 is determined based on a range in which the comparison / inspection unit 404 configured by the ASIC can compare pixel values at a time as described above, for example.

  Another method is to first determine whether each pixel is normal or defective based on the comparison result between the difference value calculated for each pixel and the threshold value, and count the number of pixels determined to be defective and the count value. There is a method of comparing the threshold value set for. Further, instead of determining the defect for each predetermined range described above, the presence or absence of a defect may be determined for each pixel.

  By such processing, the difference value is calculated after the read image and the master image are aligned. For example, even if there is a difference in scale between the entire read image and the entire master image, it is possible to reduce the influence of the scale by dividing and aligning for each range as shown in FIG. It becomes.

  In addition, in each of the divided ranges as shown in FIG. 5, it is predicted that the amount of positional deviation between adjacent ranges is relatively close. Therefore, when performing the comparison inspection for each divided range, the calculation is performed while shifting the image in the vertical and horizontal directions by performing the above-described calculation while shifting the image in the vertical and horizontal directions with the positional deviation amount determined by the comparative inspection of the adjacent region as the center. Even if the number of times of performing is reduced, there is a high possibility that the calculation based on the accurate overlay position is executed, and the calculation amount as a whole can be reduced.

  In the above description, a case where the comparison inspection unit 404 calculates and outputs a difference value between a pixel constituting the master image and a pixel constituting the read image, and the inspection control unit 403 compares the difference value with a threshold value. As an example. In addition, the comparison / inspection unit 404 compares the difference value with the threshold value, and the comparison result, that is, for each pixel constituting the read image, whether or not the difference from the corresponding pixel in the master image exceeds a predetermined threshold value. Such information may be acquired by the inspection control unit 403. Thereby, the comparison processing with the threshold value in the inspection control unit 403 is transferred to the comparison inspection unit 404 side, and the processing speed can be increased by using hardware.

  Further, the inspection control unit 403 according to the present embodiment, in principle, stores all the information on the inspection result generated by the comparative inspection executed as described above and the printing condition information received from the engine controller 2 in the storage medium. Remember and save. Then, when the free capacity of the storage medium is equal to or less than a predetermined threshold value, a refresh process is performed to delete information that is less necessary based on the result of the comparison inspection and the printing condition information. This process is one of the gist according to the present embodiment. Details will be described later.

  Next, the mechanical configuration of the print engine 3 and the inspection apparatus 4 and the paper conveyance path will be described with reference to FIG. As shown in FIG. 6, the print processing unit 301 included in the print engine 3 according to the present embodiment includes photosensitive drums 12 </ b> Y, 12 </ b> M, 12 </ b> C, and 12 </ b> K (hereinafter referred to as “photosensitive drums”) along the conveyance belt 11 that is an endless moving unit. In general, the photosensitive drum 12 is arranged in a row, and is called a so-called tandem type. That is, along the conveyance belt 11 that is an intermediate transfer belt on which an intermediate transfer image to be transferred to a sheet (an example of a recording medium) fed from the sheet feed tray 13 is formed, Photosensitive drums 12Y, 12M, 12C, and 12K are arranged in order from the upstream side.

  Each color image developed with toner on the surface of the photosensitive drum 12 for each color is superimposed on the conveyor belt 11 and transferred to form a full color image. The full-color image formed on the transport belt 11 in this way has a sheet surface of the paper transported on the path by the function of the transfer roller 14 at a position closest to the paper transport path indicated by a broken line in the drawing. Transcribed above.

  The paper on which the image is formed on the paper surface is further conveyed, the image is fixed by the fixing roller 15, and then conveyed to the inspection device 4. In the case of double-sided printing, the sheet on which an image is formed and fixed on one side is conveyed to the reversing path 16 and is reversed and conveyed to the transfer position of the transfer roller 14 again.

  The reading device 400 is configured by an information processing device inside the inspection device 4 by reading each surface of the paper conveyed from the print processing unit 301 in the paper conveyance path inside the inspection device 4 and generating a read image. The image is output to the read image acquisition unit 401. Further, the paper whose surface is read by the reading device 400 is further conveyed through the inside of the inspection device 4 and discharged to the paper discharge tray 410. 6 shows an example in which the reading device 400 is provided only on one side of the paper in the paper transport path in the inspection device 4, but in order to enable inspection of both sides of the paper, The reading device 400 may be arranged on each of both sides.

  Next, a functional configuration of the master image processing unit 402 according to the present embodiment will be described. FIG. 7 is a block diagram showing an internal configuration of the master image processing unit 402. As shown in FIG. 7, the master image processing unit 402 includes a low-value / multi-value conversion processing unit 421, a resolution conversion processing unit 422, a color conversion processing unit 423, and an image output processing unit 424. Note that the master image processing unit 402 according to the present embodiment is realized by operating the dedicated device 80 described in FIG. 2, that is, hardware configured as an ASIC, according to software control.

  The low-value / multi-value conversion processing unit 421 generates a multi-value image by performing low-value / multi-value conversion processing on a binary image expressed in colored / colorless. The bitmap data according to the present embodiment is information to be input to the print engine 3, and the print engine executes image formation output based on CMYK (Cyan, Magenta, Yellow, blackK) color binary images. On the other hand, the read image, which is the image to be inspected, is a multi-valued image of RGB (Red, Green, Blue), which is the basic three primary colors, and is a multi-valued image. The image is converted into a multi-valued image. As the multivalued image, for example, an image expressed by 8 bits for each of CMYK can be used.

  The small value / multivalue conversion processing unit 421 performs an 8-bit extension process and a smoothing process as the small value / multivalue conversion process. The 8-bit extension process is a process of converting 0/1 data, which is 1 bit, into 8 bits, converting “0” to “0” and converting “1” to “255”. The smoothing process is a process of smoothing an image by applying a smoothing filter to 8-bit data.

  In this embodiment, the print engine 3 executes image formation output based on CMYK binary images, and the master image processing unit 402 includes a low-value multi-value conversion processing unit 421. Is an example. That is, when the print engine 3 executes image formation output based on a multi-value image, the low-value multi-value conversion processing unit 421 can be omitted.

  In addition, the print engine 3 may have a function of performing image formation output based on a low-value image such as 2 bits instead of 1 bit. In that case, it is possible to cope with the 8-bit expansion process. That is, in the case of 2 bits, the gradation value is four values of 0, 1, 2, and 3. Therefore, in the case of 8-bit expansion, “0” is converted to “0”, “1” is converted to “85”, “2” is converted to “170”, and “3” is converted to “255”.

  The resolution conversion processing unit 422 performs resolution conversion so that the resolution of the multi-value image generated by the small-value multi-value conversion processing unit 421 matches the resolution of the read image that is the image to be inspected. In the present embodiment, since the reading device 400 generates a 200 dpi read image, the resolution conversion processing unit 422 converts the resolution of the multi-valued image generated by the small-value multi-value conversion processing unit 421 to 200 dpi. In addition, the resolution conversion processing unit 422 according to the present embodiment determines the size of the image after resolution conversion based on a predetermined magnification in consideration of the shrinkage of the paper output by the print processing unit 301 during resolution conversion. adjust.

  The color conversion processing unit 423 acquires an image whose resolution has been converted by the resolution conversion processing unit 422, and performs gradation conversion and color expression format conversion. The tone conversion processing is color tone conversion processing for matching the color tone of the master image with the color tone of the image formed on the paper surface by the print processing unit 301 and the color tone of the image read and generated by the reading device 400. .

  Such processing includes, for example, an image including color patches of various gradation colors formed on the paper surface by the print processing unit 301, and the gradation value of each color patch in the read image generated by reading the paper. This is performed using a gradation conversion table in which the gradation values in the original image for forming each color patch are associated with each other. That is, the color conversion processing unit 423 converts the gradation value of each color of the image output from the resolution conversion processing unit 422 based on such a gradation conversion table.

  The color representation format conversion process is a process for converting an image in the CMYK format into an image in the RGB format. As described above, since the read image according to this embodiment is an RGB format image, the color conversion processing unit 423 converts the CMYK format image that has been subjected to the gradation conversion processing into an RGB format. As a result, a 200 dpi multi-valued image expressed by 8 bits (total 24 bits) of each RGB color is generated for each pixel. That is, in the present embodiment, the small-value / multi-value conversion processing unit 421, the resolution conversion processing unit 422, and the color conversion processing unit 423 function as an inspection image generation unit.

  The image output processing unit 424 outputs the master image generated by the processing up to the color conversion processing unit 423. As a result, the inspection control unit 403 acquires a master image from the master image processing unit 402.

  Next, a functional configuration of the inspection control unit 403 according to the present embodiment will be described. FIG. 8 is a block diagram illustrating a functional configuration of the inspection control unit 403 according to the present embodiment. FIG. 9 is a flowchart showing an image inspection operation for one page by the inspection control unit 403 according to the present embodiment. As shown in FIG. 8, the inspection control unit 403 according to the present embodiment includes an information input unit 431, a defect determination unit 432, a controller communication unit 433, a storage processing unit 434, a free space determination unit 435, and a refresh processing unit 436. .

  In the inspection control unit 403 according to the present embodiment, as shown in FIG. 9, first, the controller communication unit 433 acquires print condition information from the engine controller 2 (S901). That is, the controller communication unit 433 functions as a printing condition information acquisition unit. As described with reference to FIG. 4, the “inspection result information identification ID” in the printing condition information is attached in the inspection apparatus 4, and is still blank in S <b> 901. The information input unit 431 acquires a master image from the master image processing unit 402 (S902), and acquires a read image from the read image acquisition unit 401 (S903).

  As described with reference to FIG. 5, the information input unit 431 that has acquired the master image and the read image extracts a predetermined range of images from the master image and the read image and inputs the images to the comparison test unit 404. In step S904, the image comparison inspection is executed in step S404. Note that the processing of S901 and the processing of S902 to S904 are not limited in context, and may be executed in the reverse order or may be executed in parallel.

  By the processing of S904, the difference between the pixels constituting the master image and each pixel constituting the read image is calculated, and a difference image having the difference value calculated for each pixel as a pixel is generated. For example, when there is no defect in the read image and the pixel values of the pixels constituting the master image and the pixel values of the pixels constituting the read image completely match each other, the pixel values of the pixels constituting the difference image are zero. .

  On the other hand, when the read image has a defect, a difference occurs between the pixel value of the pixel constituting the master image and the pixel value of the pixel constituting the read image, and the difference value is the pixel value of the pixel constituting the difference image. It becomes. Therefore, defect determination can be performed based on the pixel value of the difference image generated in this way. The defect determination unit 432 acquires the difference image generated by the process of S904, and performs defect determination processing based on the acquired difference image (S905).

  In S905, the defect determination unit 432 performs various processes based on the pixel value of each pixel constituting the difference image, that is, the difference value between the master image and the read image, so that the page corresponding to the read image is defective. It is determined in detail whether or not, and inspection result information as shown in FIG. 10 is generated. That is, the defect determination unit 432 functions as an inspection result acquisition unit that acquires a difference image and acquires a defect determination result based on the difference image.

  As shown in FIG. 10, the inspection result information according to the present embodiment includes “inspection result information identification ID” and “defect occurrence status”. The “inspection result information identification ID” is identification information for identifying the inspection result information of each page, and corresponds to the “inspection result information identification ID” of the printing condition information described with reference to FIG.

  The defect occurrence status is information indicating the defect occurrence status of each page. In the present embodiment, as shown in FIG. 10, “defect number” is associated with each “defect type”. “Defect type” indicates the type of defect such as “streaks”, “color change”, “background stain”, and the like. The “number of defects” indicates the number of extracted defect types corresponding to each page.

  The defect determination unit 432 generates information such as “defect occurrence status” in FIG. 10 by analyzing the difference image. Specifically, conditions for determining each defect type such as “defect type A” and “defect type B” shown in FIG. 10 are set, and the pixel of each pixel included in the difference image When the value state matches the set condition, the number of defect types that satisfy the condition is counted. For example, a condition is set such that “streak” is determined when a predetermined number or more of pixels having a difference value equal to or larger than a predetermined value continue in the main scanning direction or the sub-scanning direction.

  By changing the parameter of the condition determined at the time of such analysis, the case where it is determined as a defect and the case where it is not determined as a defect are changed even in the same defect state. For example, in the case of the above-described “streak” determination, the condition is that a predetermined number or more of pixels having a difference value equal to or larger than a predetermined value are continuous, but a parameter of “predetermined value” applied to the difference value, If the “predetermined number” of parameters applied to the determination of being continuous changes, the determination result also changes. One of the gist of the present invention is to store as many differential images as possible in order to enable re-examination performed by changing parameters in this way.

  When the information as shown in FIG. 10 is generated by the processing of S905, the storage processing unit 434 displays the printing condition information acquired in S901, the difference image generated by the processing of S904, and the inspection generated by the processing of S905. The result information is stored in association with each other in the HDD 40 (S906). At this time, the storage processing unit 434 sets the “inspection result information identification ID” of the printing condition information based on the “inspection result information identification ID” included in the inspection result information generated in S905.

  After the processing of S906, the free space determination unit 435 confirms the free space of the storage capacity of the HDD 40, which is the information storage destination in S906, and determines whether the free space is insufficient (S907). In S907, the free capacity determination unit 435 calculates, for example, the ratio of the free capacity to the total storage capacity of the HDD 40 (hereinafter referred to as “free capacity ratio”), and the HDD 40 when the free capacity ratio is below a predetermined threshold. Judge that there is not enough free space. In addition, the lack of capacity may be determined by comparing the threshold set for the free capacity of the HDD 40 with the free capacity.

  As a result of the determination in S907, if the free space of the HDD 40 is insufficient (S907 / YES), the refresh processing unit 436 deletes information that is less necessary from the information accumulated in the HDD 40 by the processing in S906. The refresh process is executed (S908), and the inspection process for one page is completed.

  On the other hand, if the result of determination in S907 is that there is no shortage of free space in the HDD 40 (S907 / NO), the inspection control unit 403 ends the process as it is. The controller communication unit 433 outputs a reprint request, a print job stop request, and the like to the engine controller 2 based on the inspection result information generated in step S905.

  As described above, in the inspection apparatus 4 according to the present embodiment, all of the print condition information, the difference image, and the inspection result information (hereinafter referred to as “per-page generation information”) generated in the defect inspection of each page are once stored. The data is stored in the HDD 40, and refresh processing is performed in accordance with a decrease in the free capacity of the HDD 40. As a result, even for a page that is not determined to be defective in the processing of S905, it is possible to perform defect determination again by changing parameters such as a threshold used in the determination, and the storage capacity of the finite HDD 40 can be increased. It can be used efficiently. The generation information for each page is used as storage information that is stored by inspection of an image for each page.

  Next, functions of the refresh processing unit 436 according to the present embodiment and details of the refresh processing will be described with reference to FIG. As shown in FIG. 8, the refresh processing unit 436 includes a weight coefficient calculation unit 437, an evaluation value calculation unit 438, a deletion determination unit 439, and a deletion processing unit 440. Then, as shown in FIG. 11, in the refresh process, first, the weighting factor calculation unit 437 generates a weighting factor table (S1101).

  Here, the weighting coefficient table generated in S1101 will be described. The weighting coefficient table is used to calculate an evaluation value for determining the importance of the above-mentioned generated information for each page based on the printing condition information shown in FIG. 4 and the information included in the inspection result information shown in FIG. This is the table used.

FIG. 12 is a diagram illustrating a weighting factor table (hereinafter referred to as “weighting factor table for each operating time”) for the “operating time” in the printing condition information illustrated in FIG. 4. As shown in FIG. 12, in the weighting factor table for each operating time, the operating time is divided for each predetermined range, and the weighting factor w _time is set for each dividing range.

FIG. 13 is a diagram showing a weighting coefficient table (hereinafter referred to as “toner usage amount-specific weighting coefficient table”) for the “toner usage amount” of the printing condition information shown in FIG. As shown in FIG. 13, in the weight coefficient table for each toner usage amount, the toner usage amount for each color of CMYK is divided for each predetermined range, and a weighting factor w _ctn is set for each division range. Yes.

FIG. 14 is a diagram showing a weighting factor table (hereinafter referred to as “weighting factor table for each paper size”) for “size” in “paper attribute” of the printing condition information shown in FIG. As shown in FIG. 14, the paper size-specific weight coefficient table is a table in which weight coefficients w _A3 , w _{A4 and the} like are set for each paper size such as “A3”, “A4”, and the like.

FIG. 15 is a diagram illustrating a weighting coefficient table (hereinafter referred to as “weighting coefficient table by sheet thickness”) for “thickness” in “paper attribute” of the printing condition information illustrated in FIG. 4. As shown in FIG. 15, the paper thickness-specific weight coefficient table is a table in which the paper thickness is divided into predetermined ranges, and the weight coefficient w _ptn is set for each of the divided ranges.

FIG. 16 is a diagram showing a weighting coefficient table (hereinafter referred to as “paper type-specific weighting coefficient table”) for “type” in “paper attribute” of the printing condition information shown in FIG. As shown in FIG. 16, the weight coefficient table for each paper type is a table in which a weight coefficient w _pkn is set for each paper type such as “coated paper” and “recycled paper A”.

  The weighting coefficient tables shown in FIGS. 12 to 16 correspond to the printing condition information shown in FIG. 4, and evaluation values (hereinafter referred to as “evaluation values”) calculated in common regardless of whether or not an image is determined as a defect. It is a table for common evaluation values used for calculation of “common evaluation value”.

  When generating the common evaluation value table, a calculation based on the defect occurrence rate calculated for each item for which a weighting coefficient is calculated is performed. For example, a method for calculating the weight coefficient table for each operating time will be described. FIG. 17 is a table showing the defect occurrence rate calculated for each operation time when calculating the weight coefficient table for each operation time (hereinafter referred to as “defect occurrence rate table for each operation time”).

  As shown in FIG. 17, in the defect occurrence rate table by operation time, the defect occurrence rate is calculated for each range that is a delimitation range of “operation time” in the weight coefficient table by operation time. That is, the weight coefficient calculation unit 437 analyzes the generation information for each page stored in the HDD 40, calculates the defect occurrence rate for each range of “operation time”, and generates a table as shown in FIG. .

When the table as shown in FIG. 17 is generated, the weight coefficient calculation unit 437 calculates the weight coefficient w _timei for each range according to the following equation (1).

Here, W _time shown in Expression (1) is a constant. When this constant W _time is increased, the weighting coefficient is calculated to be large, so that it is possible to increase the influence of the operating time weighting coefficient _wtimei when calculating the evaluation value for each page generation information. .

  By performing the calculation shown in the above formula (1) for all i, the weighting factor table for each operating time shown in FIG. 12 is generated. Also in the tables shown in FIGS. 13 to 16, the weight coefficients are calculated by the same method as the above equation (1) to generate the tables.

FIG. 18 is a diagram showing a weighting coefficient table (hereinafter referred to as a “defect number-specific weighting coefficient table”) for “number of defects” in the inspection result information shown in FIG. As shown in FIG. 18, the weight coefficient table for each defect number is a table in which a weight coefficient w _nn is set for each defect number of “1”, “2”, and “3”.

Here, a method of generating the defect number-specific weight coefficient table will be described. The weighting factor calculation unit 437 calculates the weighting factor w _ni in the weighting factor table for each defect number as shown in FIG. 18 according to the following equation (2).

Here, W _n and C are constants. If the constant W _n is increased, the weighting coefficient is calculated to be large, so that it is possible to increase the influence of the defect number-specific weighting coefficient w _ni when calculating the evaluation value for each generation information for each page. In addition, when the constant C is increased, the weighting coefficient is calculated to be large. Therefore, when calculating the evaluation value for each page generation information, the weight coefficient _wni for each defect number for the image from which the defect is extracted. The influence of can be increased.

For example, in addition to the constant W _time in the above formula (1), the constants W _ct , W _mt , W _yt , W _kt , and the paper size-specific weight coefficient table used in generating the weight coefficient table for each toner usage amount are used. In the relationship between the constant W _ps , the constant W _pt used in the generation of the paper weight-specific weight coefficient table, and the constant W _pk used in the generation of the paper type-specific weight coefficient table, the following equation (3) is satisfied. The evaluation value of the per-page generation information for the image from which the defect has been extracted is necessarily larger than the evaluation value of the per-page generation information for the image from which the defect has not been extracted.

  The above constants are all used as in the above formula (1). Accordingly, each of the above constants is, in other words, the maximum value of the evaluation value calculated according to each weighting factor.

FIG. 19 is a diagram showing a weighting factor table (hereinafter referred to as “defect type-specific weighting factor table”) for the “defect type” in the inspection result information shown in FIG. 10. As shown in FIG. 19, in the weight coefficient table for each defect type, weight coefficients w _kA , w _kB , and w _kC are set for each defect type “defect type A”, “defect type B”, and “defect type C”. It has become a table.

  Here, a method of generating the defect type-specific weight coefficient table will be described. When generating the defect type-specific weight coefficient table, similarly to the generation of the common evaluation value table described with reference to FIG. 17, calculation based on the defect occurrence rate calculated for each item for which the weight coefficient is calculated is performed. . FIG. 20 is a table showing the defect occurrence rate calculated for each defect type (hereinafter referred to as “defect type defect occurrence rate table”) when calculating the defect type-specific weight coefficient table.

  As shown in FIG. 20, in the defect occurrence rate table for each defect type, the defect occurrence rate is calculated for each item of “defect type” in the defect type-specific weight coefficient table shown in FIG. That is, the weighting factor calculation unit 437 analyzes the generation information for each page stored in the HDD 40, calculates the defect occurrence rate for each item of “defect type”, and generates a table as shown in FIG. .

When the table as shown in FIG. 20 is generated, the weight coefficient calculation unit 437 calculates the weight coefficient w _ki for each range according to the following equation (4).

  The weighting coefficient tables shown in FIGS. 18 and 19 correspond to the inspection result information shown in FIG. Although the inspection result information is generated for all the images, the tables shown in FIGS. 18 and 19 are substantially meaningful only for the images from which defects are extracted. That is, the defect number-specific weight coefficient table and the defect type-specific weight coefficient table are used for calculating an evaluation value (hereinafter referred to as “defect determination evaluation value”) calculated when an image is determined as a defect. It is a table for defect determination evaluation values.

  When the generation of all the weight coefficient tables is completed, the evaluation value calculation unit 438 next selects one of the generation information for each page stored in the HDD 40 (S1102), which is common regardless of the presence / absence of defect determination. A common evaluation value calculated in step S1103 is calculated. In S1103, the evaluation value calculation unit 438 extracts the weighting coefficient corresponding to the value of each item by referring to the above-described common evaluation table based on the value of each item of the generation information for each page being selected. An evaluation value is calculated.

  When the common evaluation value is calculated, the evaluation value calculation unit 438 determines whether or not the image corresponding to the selected generation information for each page is an image for which a defect is determined (S1104). In S1104, the evaluation value calculation unit 438 refers to, for example, the inspection result information illustrated in FIG. 10, and determines that there is a defect determination image if there is even one item whose “defect number” is not zero for each “defect type”. To do.

  As a result of the determination in S1104, if the image is a defect determination image (S1104 / YES), the evaluation value calculation unit 438 calculates a defect determination evaluation value calculated only for the per-page generation information corresponding to the image determined to be defective. (S1105). In S1105, the evaluation value calculation unit 438 responds to the value of each item by referring to the above-described defect determination evaluation value table based on the value of each item of the generation information for each page being selected, as in S1103. A defect determination evaluation value is calculated by extracting a weighting coefficient.

  After the processing of S1105 is completed, or when the result of determination in S1104 is not a defect determination image (S1104 / NO), the evaluation value calculation unit 438 calculates the total value of the calculated evaluation values (S1106). The total value of the evaluation values calculated in this manner is the evaluation value for the selected generation information for each page. As shown in FIG. 21, the evaluation value of the page generation information is associated with an inspection result information identification ID that is unique for each page generation information.

  The evaluation value calculation unit 438 repeats the process until the process from S1102 is completed for all the generation information for each page stored in the HDD 40 (S1107 / NO). When the processing from S1102 is completed for all the generation information for each page stored in the HDD 40 (S1107 / YES), the deletion determination unit 439 generates the evaluation value for all the generation information for each page by the evaluation value calculation unit 438. The generation information for each page to be deleted is determined (S1108). That is, the deletion determination unit 439 functions as a deletion determination unit.

  FIG. 22 is a diagram illustrating an example of a frequency distribution for evaluation values. As illustrated in FIG. 22, the deletion determining unit 439 divides the evaluation value into predetermined ranges, and generates “number of cases”, “frequency”, and “cumulative frequency” for each range of the evaluation values. “Number of cases” is the number of pieces of generated information for each page included in the range of the evaluation value. “Frequency” is the ratio of the generated information per page included in the range of the evaluation value with respect to the number of generated information per page. “Cumulative frequency” is a value obtained by summing up “frequency” from the lowest evaluation value side when frequency distributions are arranged in ascending order of evaluation value.

  When the frequency distribution is analyzed as illustrated in FIG. 22, the deletion determination unit 439 specifies a range of evaluation values having a cumulative frequency exceeding 10%, and determines generation information for each page that is equal to or less than the specified evaluation value as a deletion target. In other words, the deletion determination unit 439 determines that the generation information for each page below the evaluation value at which the cumulative frequency obtained by summing the frequencies in order from the lowest evaluation value reaches the predetermined threshold is to be deleted. In the example of FIG. 22, generated information for each page having an evaluation value of 0.8 to 1.0 or less is a deletion target.

  When the deletion determination unit 439 determines the generation information for each page to be deleted by the deletion determination unit 439 in the process of S1108, the deletion processing unit 440 deletes the generation information for each page determined as the deletion target from the HDD 40 (S1109), and refresh processing Ends.

  According to the processing shown in FIG. 11, since the evaluation value is specified so that the cumulative frequency exceeds 10% in S1108, at least 10% of the storage capacity used for storing the generated information for each page in the HDD 40. Will increase free space. However, this is merely an example, and the threshold value applied to the cumulative frequency in order to specify the evaluation value may be other than 10%, and is appropriately selected according to the free space to be increased in one refresh process.

  In the present embodiment, as described with reference to FIG. 9, it is determined whether the free space is insufficient each time the generated information for each page is stored in the HDD 40, and the refresh process is performed when the free space is insufficient. However, this is only an example, and the determination of insufficient free space may be made at another timing.

  In addition, the refresh process may be performed periodically, not only when the free space is insufficient. However, it is preferable to keep the saved information for each page as much as possible, and in that respect, the periodic refresh process is not efficient. As described above, by performing the refresh process only when the free space is insufficient, the free space of the HDD 40 can be efficiently ensured while saving the generated information for each page as much as possible.

  As described above, according to the inspection apparatus 4 according to the present embodiment, in principle, all the difference images and inspection result information generated in the comparison inspection between the master image and the read image are stored. Therefore, the defect determination can be performed again after changing the defect determination conditions. In addition, the information refresh process is performed at a predetermined timing in order to prevent the storage capacity of the storage medium from being insufficient due to all the difference images and the inspection result information being saved.

  For the refresh process, the inspection apparatus 4 according to the present embodiment stores, in association with the difference image and the inspection result information, printing condition information indicating a condition at the time of image formation output. In the refresh process, the importance level of the difference image and the inspection result information is evaluated based on the printing condition information, and the refresh process is performed so as to delete the information with the lower importance level. It is possible to suitably determine whether to save the result information.

  In calculating the importance, each item included in the printing condition information is weighted based on the past defect occurrence rate, and a value indicating the importance is calculated based on the weighting value. For this reason, it is possible to calculate the importance according to the actual inspection result.

1 DFE
2 Engine Controller 3 Print Engine 4 Inspection Device 5 Interface Terminal 10 CPU
20 RAM
30 ROM
40 HDD
50 I / F
60 LCD
70 Operation Unit 80 Dedicated Device 90 Bus 11 Conveyor Belt 12, 12Y, 10M, 12C, 12K Photosensitive Drum 13 Paper Tray 14 Transfer Roller 15 Fixing Roller 16 Reverse Pass 101 Job Information Processing Unit 102 RIP Processing Unit 201 Data Acquisition Unit 202 Engine control unit 203 Bitmap transmission unit 301 Print processing unit 400 Reading device 401 Read image acquisition unit 402 Master image processing unit 403 Inspection control unit 404 Comparison inspection unit 410 Paper discharge tray 421 Low-value multi-value conversion processing unit 422 Resolution conversion processing unit 423 Color conversion processing unit 424 Image output processing unit 431 Information input unit 432 Defect determination unit 433 Controller communication unit 434 Storage processing unit 435 Free space determination unit 436 Refresh processing unit 437 Weight coefficient calculation unit 438 Evaluation value calculation unit 439 Delete Judgment unit 440 Deletion processing unit

JP 2011-114574 A JP-A-2005-205722

Claims (8)

An image inspection apparatus for inspecting a read image obtained by reading an image formed and output on a recording medium,
A read image acquisition unit that acquires a read image generated by reading an image formed and output; and
In order to inspect the read image, a difference image indicating a difference between the image for inspection generated based on information of an image to be imaged and output and the read image, and a defect in the read image based on the difference image An inspection result acquisition unit for acquiring an inspection result which is the determined result;
A printing condition information acquisition unit that acquires printing condition information indicating a condition when an image that is an original image of a scanned image that is an inspection target is output;
A storage processing unit that associates the difference image, the inspection result, and the printing condition information, and stores it in a storage medium as storage information stored by image inspection;
An evaluation value calculation unit that calculates an evaluation value indicating the importance of the storage information based on the printing condition information and the inspection result;
A deletion determination unit that determines storage information to be deleted from the storage medium based on the calculated evaluation value;
An image inspection apparatus comprising: a deletion processing unit that deletes the determined stored information to be deleted.   The deletion determination unit analyzes the calculated frequency distribution of the evaluation values, and deletes the stored information that is equal to or lower than the evaluation value at which the cumulative frequency obtained by summing up the frequencies in order from the lowest evaluation value reaches a predetermined threshold value. The image inspection apparatus according to claim 1, wherein the image inspection apparatus is determined as power storage information.   The evaluation value calculation unit calculates an evaluation value for each of a plurality of items included in the printing condition information, and calculates an evaluation value of the storage information based on the calculated plurality of evaluation values. The image inspection apparatus according to 1 or 2.   The evaluation value calculation unit performs weighting according to a past defect occurrence rate for each of a plurality of items included in the printing condition information, and calculates the evaluation value according to a result of the weighting. The image inspection apparatus according to claim 3.   The printing condition information includes items relating to a state of the image forming apparatus when an image which is a source of a scanned image to be inspected is output and output, and items relating to contents of the original image forming output. The image inspection apparatus according to claim 3 or 4. The evaluation value calculation unit calculates the evaluation value when it is determined that a free capacity of a storage medium for storing the saved information is equal to or less than a predetermined value,
The image inspection apparatus according to claim 1, wherein the deletion determination unit determines the storage information to be deleted when the evaluation value is calculated. An image forming system having a function of inspecting a read image obtained by reading an image formed and output on a recording medium,
An image forming unit that performs image forming output on the recording medium;
An image reading unit that reads an image formed on the recording medium and generates a read image;
A read image acquisition unit for acquiring the read image;
In order to inspect the read image, a difference image indicating a difference between the image for inspection generated based on information of an image to be imaged and output and the read image, and a defect in the read image based on the difference image An inspection result acquisition unit for acquiring an inspection result which is the determined result;
A printing condition information acquisition unit that acquires printing condition information indicating a condition when an image that is an original image of a scanned image that is an inspection target is output;
A storage processing unit that associates the difference image, the inspection result, and the printing condition information, and stores it in a storage medium as storage information stored by image inspection;
An evaluation value calculation unit that calculates an evaluation value indicating the importance of the storage information based on the printing condition information and the inspection result;
A deletion determination unit that determines storage information to be deleted from the storage medium based on the calculated evaluation value;
An image forming system, comprising: a deletion processing unit that deletes the determined storage information to be deleted. An image inspection program for inspecting a read image obtained by reading an image formed and output on a recording medium,
Obtaining a read image generated by reading an image formed and output; and
In order to inspect the read image, a difference image indicating a difference between the image for inspection generated based on information of an image to be imaged and output and the read image, and a defect in the read image based on the difference image Obtaining a test result that is a result of the determination;
A step of acquiring printing condition information indicating a condition when an image that is an original image of a scanned image to be inspected is output;
Associating the difference image, the inspection result and the printing condition information, and storing them in a storage medium as storage information stored by image inspection;
Calculating an evaluation value indicating the importance of the stored information based on the printing condition information and the inspection result;
Determining stored information to be deleted from the storage medium based on the calculated evaluation value;
An image inspection program causing an information processing apparatus to execute the step of deleting the determined stored information to be deleted.

Images