JP2014182551A - Inspection apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of maintenance of an image forming apparatus.SOLUTION: An inspection apparatus includes: a read image acquisition unit 30 which acquires a read image formed by reading a recording medium with an image formed thereon; a defect determination unit 34 which determines whether a difference between the acquired read image and an image used by forming the image on the recording medium exceeds a first threshold for determining an image forming defect; a defect sign determination unit 36 which determines whether a difference between the acquired read image and the image used by forming the image on the recording medium exceeds a second threshold which is lower than the first threshold and used for determining a defect sign; and a storage control unit 48 which controls the acquired read image to be stored when the defect determination unit 34 or the defect sign determination unit 36 determines that the threshold is exceeded.

Description

  The present invention relates to an inspection apparatus and a program.

  Patent Document 1 discloses a two-dimensional image sensor that is arranged opposite to an inspection surface of an inspection object and a level change amount per predetermined time of a continuous image signal output from the image sensor in a scanning line direction. And a second level change amount detecting means for continuously detecting a level change amount at a point where two image signals in the scanning line direction outputted from the image sensor are synchronized with each other. And a pair of defect point detection means for comparing the absolute value of the level change detected by both means with a preset threshold value and detecting as a defect point when the absolute value is larger than the threshold value, The defect points detected by both means are counted, and whether or not each count value is within a preset standard value is detected. It discloses the appearance inspection apparatus characterized by comprising a pair of quality decision means for watching quality decision.

  Also, cited document 2 discloses an inspection apparatus that detects an abnormality of an object surface by processing two-dimensional data obtained through a television camera or the like.

Japanese Unexamined Patent Publication No. 60-95335 JP-A 63-180176

  An object of the present invention is to provide an inspection apparatus and a program that can improve the maintenance efficiency of an image forming apparatus.

  According to the first aspect of the present invention, a read image acquisition unit that acquires a read image obtained by reading a recording medium on which image formation has been performed, a read image acquired by the read image acquisition unit, and image formation on the recording medium Acquired by the read image acquisition unit, a first determination unit that determines whether or not a difference from the formed image used in step S1 exceeds a first threshold for determining whether there is a defect in image formation. A second threshold value that is lower than the first threshold value for determining whether or not a difference between the read image and a formed image used in image formation on the recording medium is a sign of a defect A second determination unit that determines whether or not the threshold value exceeds a threshold value by the first determination unit or the second determination unit, the read image acquired by the read image acquisition unit To remember An inspection device having a Gosuru storage control unit.

  The present invention according to claim 2 is the inspection apparatus according to claim 1, wherein the second determination unit sets an image region wider than an image region to be determined by the first determination unit.

  According to a third aspect of the present invention, there is provided a classification unit that classifies read images that are determined to exceed a threshold by the second determination unit, and a plurality of read images that are classified into the same set by the classification by the classification unit. The storage control means further comprises an image selection means for selecting a read image to be stored, and the storage control means controls to store the read image selected by the image selection means. 2. The inspection apparatus according to 2.

  According to a fourth aspect of the present invention, the image selecting unit selects a read image including a precursor portion of a defect having the highest degree of defect among a plurality of read images classified into the same set by classification by the classification unit. The inspection apparatus according to claim 3.

  The present invention according to claim 5 is the inspection apparatus according to claim 3 or 4, wherein the classification means classifies according to the position of the precursor portion of the defect in the main scanning direction.

  According to a sixth aspect of the present invention, in the classifying unit, a difference between a presence interval in the sub-scanning direction of a plurality of defect precursors and a predetermined interval for each cause of occurrence of a defect precursor is predetermined. The inspection apparatus according to claim 5, wherein the read images including the precursor portion of the defect are classified into the same set when the difference is within the range.

  In the present invention according to claim 7, the second threshold value is set when the number of read images determined to exceed the threshold value by the second determination unit exceeds a predetermined value. The inspection apparatus according to claim 1, further comprising a threshold value changing unit that changes the value to a value higher than the value.

  The present invention according to claim 8 further includes warning means for warning when a difference between the first threshold value and the second threshold value is within a predetermined range, and the threshold value changing means includes: The inspection apparatus according to claim 7, wherein the value of the second threshold value is increased according to the number of read images determined to exceed the threshold value by the second determination unit.

  According to a ninth aspect of the present invention, there is provided a read image acquisition unit that acquires a read image obtained by reading a recording medium on which an image has been formed, a read image acquired by the read image acquisition unit, and image formation on the recording medium. Determining means for determining whether or not a difference from the formed image used in the step exceeds a predetermined threshold; a classification means for classifying the read image determined to exceed the threshold by the determining means; and Image selection means for selecting a read image to be stored among a plurality of read images classified into the same set by classification by the classification means, and storage control for controlling to store the read image selected by the image selection means And an inspection device.

  According to the tenth aspect of the present invention, a difference between a read image obtained by reading a recording medium on which image formation has been performed and a formed image used in image formation on the recording medium is a defect in image formation. A difference between a first determination step for determining whether or not a first threshold value for determining presence or absence exceeds a read image and a formed image used in image formation on the recording medium is a defect. A second determination step for determining whether or not there is a precursor of the second, a second determination step for determining whether or not a second threshold value lower than the first threshold value is exceeded, and the first determination step or the second When it is determined that the threshold value is exceeded in this determination step, the program causes the computer to execute a storage control step for controlling to store the read image.

  According to the eleventh aspect of the present invention, a difference between a read image obtained by reading a recording medium on which image formation has been performed and a formed image used in image formation on the recording medium is a predetermined threshold value. A determination step for determining whether or not a threshold value is exceeded, a classification step for classifying the read image determined to exceed a threshold value in the determination step, and a plurality of readings classified into the same set by classification in the classification step This is a program for causing a computer to execute an image selection step for selecting a read image to be stored among images and a storage control step for controlling to store the selected read image.

  According to the first aspect of the present invention, it is possible to provide an inspection apparatus capable of improving the maintenance efficiency of the image forming apparatus as compared with the case where the present configuration is not provided.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, there is provided an inspection apparatus capable of capturing a precursor of a defect that has occurred in an image area that is not targeted in the determination of the presence or absence of a defect. be able to.

  According to the third aspect of the present invention, in addition to the effects of the first aspect of the present invention according to the first or second aspect, the inspection can reduce the data amount of the stored image compared to the case where the present configuration is not provided. An apparatus can be provided.

  According to the fourth aspect of the present invention, in addition to the effect of the present invention according to the third aspect, it is possible to ensure an image that can easily confirm a sign of a defect as compared with the case where the present configuration is not provided. An apparatus can be provided.

  According to the fifth aspect of the present invention, in addition to the effect of the present invention according to the third or fourth aspect, there is provided an inspection apparatus capable of classifying a precursor of a streak defect generated on a recording medium. be able to.

  According to the sixth aspect of the present invention, in addition to the effect of the present invention according to the fifth aspect, it is possible to provide an inspection apparatus capable of classifying a precursor of a point-like defect generated on a recording medium. it can.

  According to the seventh aspect of the present invention, in addition to the effect of the present invention according to any one of the first to sixth aspects, the stored data amount can be suppressed as compared with the case where the present configuration is not provided. An apparatus can be provided.

  According to the eighth aspect of the present invention, in addition to the effect of the present invention according to the seventh aspect, it is possible to provide an inspection apparatus capable of predicting the occurrence of image formation defects.

  According to the ninth aspect of the present invention, it is possible to provide an inspection apparatus capable of suppressing the amount of stored image data as compared with the case where the present configuration is not provided.

  According to the tenth aspect of the present invention, it is possible to provide a program capable of improving the maintenance efficiency of the image forming apparatus as compared with the case where the present configuration is not provided.

  According to the present invention of claim 11, it is possible to provide a program capable of suppressing the amount of stored image data as compared to the case without this configuration.

1 is a schematic diagram illustrating an example of a configuration of an image forming system 2 according to an embodiment of the present invention. It is a block diagram which shows an example of a hardware structure of the test | inspection apparatus 8 which concerns on embodiment of this invention. It is a block diagram which shows the function structure of the test | inspection apparatus 8 implement | achieved by running a program. It is a schematic diagram explaining the log | history information memorize | stored by the memory | storage control part 48, (a) shows an example of the log | history information produced | generated by the defect precursor information generation part 40, (b) is classified by the classification | category part 42. An example of the recorded history information and the partial image selected by the image selection unit 46 is shown. 5 is a flowchart showing an example of the operation of the inspection apparatus 8. It is a flowchart which shows the detail of the process of step 126 shown in FIG. It is a flowchart which shows the detail of the process of step 220 shown in FIG. It is a flowchart which shows the detail of the process of step 218 shown in FIG. 6, and step 318 shown in FIG.

Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of a configuration of an image forming system 2 according to an embodiment of the present invention. The image forming system 2 according to the embodiment of the present invention includes a paper feeding device 4, an image forming device 6, an inspection device 8, and a post-processing device 10.

  The paper feeding device 4 supplies a recording medium such as roll paper to the image forming device 6. The post-processing device 10 is a device that performs post-processing such as cutting on the recording medium on which an image is formed by the image forming device 6.

  The image forming apparatus 6 includes, for example, a photosensitive drum (not shown) that holds toner images of each color of Y (yellow), M (magenta), C (cyan), and K (black). Image formation is performed on the supplied recording medium. For example, the image forming apparatus 6 forms an image corresponding to a print job (print request) on a recording medium.

  Next, the inspection apparatus 8 will be described. The inspection apparatus 8 is an apparatus that inspects the quality of image formation based on a read image obtained by reading a recording medium on which an image is formed by the image forming apparatus 6 using an image reading apparatus 12 such as a scanner. In this embodiment, the configuration in which the inspection device 8 includes the image reading device 12 will be described as an example. However, the inspection device 8 may not include the image reading device 12, and the image forming device 6 may perform image processing. You may receive the read image of the formed recording medium from another apparatus. Further, the read image is not limited to an image read by a scanner or the like, but may be an image taken by a camera or the like.

FIG. 2 is a block diagram illustrating an example of a hardware configuration of the inspection apparatus 8.
As shown in FIG. 2, the inspection device 8 transmits and receives data to and from other devices via a CPU 14, a memory 16, a storage device 18 such as a hard disk drive (HDD), and a network (not shown). An interface (IF) 20, an input / output device 22, and the image reading device 12 described above are included, and these components are connected to each other via a control bus 24.

  The CPU 14 executes processing based on a program stored in the memory 16 or the storage device 18 and controls the operation of the inspection device 8. The storage device 18 stores history information described later. The input / output device 22 includes, for example, a display device that displays information and an input reception device that receives input made by an operator.

  In the present embodiment, the CPU 14 has been described as reading and executing a program stored in the memory 16 or the storage device 18, but the program is stored in a storage medium such as a CD-ROM and provided to the CPU 14. It is also possible to do.

  FIG. 3 is a block diagram showing a functional configuration of the inspection apparatus 8 realized by executing the program.

  As shown in FIG. 3, the inspection apparatus 8 includes a read image acquisition unit 30, a formed image acquisition unit 32, a defect determination unit 34, a defect precursor determination unit 36, a defect information generation unit 38, and defect precursor information. Generation unit 40, classification unit 42, period information storage unit 44, image selection unit 46, storage control unit 48, defect / defect precursor information storage unit 50, output unit 52, threshold change unit 54, And a warning unit 56.

  The read image acquisition unit 30 acquires a read image obtained by reading a recording medium on which an image is formed by the image forming apparatus 6. In the present embodiment, the read image data read by the image reading device 12 is acquired. However, the read image data may be received and acquired via the communication IF 20, or read stored in a portable storage medium or the like. Image data may be read and acquired.

  The formed image acquisition unit 32 acquires a formed image used in image formation on a recording medium. The formed image acquisition unit 32 acquires image data such as bitmap data based on print job data developed by RIP (Raster Image Processor), for example. The formed image acquisition unit 32 may receive and acquire the formed image data via the communication IF 20, or read and acquire the formed image data stored in a portable storage medium or the like. Also good.

  The defect determination unit 34 is acquired by the read image acquisition unit 30 that is a read image obtained by reading the formed image acquired by the formed image acquisition unit 32 and the recording medium on which the formed image is formed. By comparing with the read image, it is determined whether there is a defect in image formation quality of the image forming apparatus 6.

  Specifically, the defect determination unit 34 uses a difference between the read image acquired by the read image acquisition unit 30 and a formed image corresponding to the read image to determine whether there is a defect in image formation. It is determined whether or not a threshold value (hereinafter referred to as a defect determination threshold value) is exceeded. When the difference exceeds the defect determination threshold value, it is determined that there is a defect in the image formation quality by the image forming apparatus 6, and when the difference does not exceed the defect determination threshold value, the image formation quality by the image forming apparatus 6 is improved. It is determined that there is no defect.

  For example, the defect determination unit 34 obtains the difference in brightness between the read image and the image to be formed corresponding to the read image, and determines the magnitude of the brightness difference for the portion where the brightness difference occurs in the image area. An evaluation value representing the difference between the two images is calculated based on the size of the area, and it is determined whether or not the calculated evaluation value exceeds a predetermined defect determination threshold value.

  Here, the image region to be determined by the defect determination unit 34 may be a partial region of the read image. For example, when the post-processing device 10 performs a cutting process on a recording medium on which an image is formed by the image forming apparatus 6, the region to be cut out by the cutting may not be a determination target. Further, for example, when a recording medium on which an image is formed by the image forming apparatus 6 is used as a material for a packaging container, a portion that is not exposed on the outer surface of the packaging container is excluded from a determination target region of the defect determination unit 34. Also good.

  The defect sign determination unit 36 compares the formed image acquired by the formed image acquisition unit 32 with the read image obtained by reading the recording medium on which the formed image is formed, and determines the image forming apparatus 6. Whether or not there is a precursor to a defect in image formation quality is determined. Note that a precursor of a defect means a defect of quality that is not as bad as a defect.

  Specifically, the defect sign determination unit 36 determines whether or not a difference between the read image acquired by the read image acquisition unit 30 and a formed image corresponding to the read image is a sign of a defect in image formation. It is determined whether or not a second threshold value (hereinafter referred to as a defect sign determination threshold value) is exceeded. However, the defect sign determination threshold value is a threshold value for determining a defect of quality that is not so high as a defect, and thus is set as a value that is stricter than the defect determination threshold value. In the present embodiment, the defect sign determination threshold is set lower than the defect determination threshold. When the difference exceeds the defect precursor determination threshold, it is determined that there is a defect precursor in the image formation quality by the image forming apparatus 6, and when the difference does not exceed the defect precursor determination threshold, the image by the image forming apparatus 6 is detected. It is determined that there is no sign of defects in the quality of formation.

  In the present embodiment, the defect sign determination unit 36 sets an image area wider than the image area to be determined by the defect determination unit 34 as a determination target. For example, the defect sign determination unit 36 sets the entire area of the read image as a determination target. Note that the determination target of the defect sign determination unit 36 of the present embodiment is described as an image area wider than the defect determination unit 34, but the defect sign determination unit 36 may use the same image area as the defect determination unit 34 as a determination target. Good.

  When the defect determination unit 34 determines that the read image has a quality defect, the defect information generation unit 38 creates history information (log information) about the defect. In the present embodiment, the defect information generation unit 38 generates, for each defect, history page information, an occurrence position, a defect type, a partial image of the defect part, a defect defect degree, and the like as history information.

  Here, the generated page number indicates what page the defect has occurred in a series of pages on which an image is formed by a print job. The occurrence position indicates the position of the defect in the main scanning direction and the position in the sub scanning direction. The defect type is, for example, the type of whether the defect is a dot-like defect, a stripe-like (linear) defect, a white defect, or a non-white color defect. Show. The partial image of the defective part is obtained by cutting out a partial image including the defective part from the read image. In this embodiment, the partial image is used as the history information, but the read image may be used as the history information. The degree of defect defect is a value indicating the degree of defect defect, and is determined based on, for example, a difference value used by the defect determination unit 34.

  The defect precursor information generation unit 40 creates history information (log information) about a precursor of the defect when the defect precursor determination unit 36 determines that the read image has a precursor of a quality defect. In the present embodiment, the defect precursor information generation unit 40, similar to the defect information generator 38, for the precursor of each defect, the generation page number, the generation position, the type of defect precursor, the partial image of the defect precursor, The degree of sign failure is generated as history information. Thus, not only the defect information but also the information of the defect precursor is left as the history information, so that maintenance based on the information of the precursor of the defect is performed.

  The classification unit 42 classifies the read image determined by the defect sign determination unit 36 to exceed the defect sign determination threshold. Specifically, the classification unit 42 classifies the read images that are presumed to have the same cause of occurrence of a defect precursor into the same class (set). In the present embodiment, by classifying the history information generated by the defect precursor information generating unit 40, the read image or a partial image of the defect precursor of the read image is classified.

  In the present embodiment, the classification unit 42 classifies history information according to the presence position of the defect precursor in the main scanning direction for the precursor of the streak defect. The classification unit 42 estimates that the precursors of the streak defects having the same position in the main scanning direction are the same, and classifies them into the same set. Note that the same position in the main scanning direction is not limited to the case where the positions completely match, but may include the case where the difference in position in the main scanning direction is within a predetermined range.

  Further, with respect to the precursor of the point-like defect, the classification unit 42 classifies the history information according to the position in the sub-scanning direction of the defect precursor. The classification unit 42 classifies the plurality of defect precursors into the same set when the interval in the sub-scanning direction of the plurality of defect precursors and the interval predetermined for each cause of the defect precursor are the same. Note that the case where the existence interval is the same as the predetermined interval is not limited to the case where the intervals completely match, and may include the case where the difference is within a predetermined range.

  Specifically, the classification unit 42 classifies the precursor of the point-like defect as follows. First, in the cycle information storage unit 44, for each cause that causes a defect sign, an occurrence interval when a defect sign occurs due to the cause is stored. The period information storage unit 44 of the present embodiment stores the period of the rotating parts used in the image forming apparatus 6 for each rotating part. For example, the period information storage unit 44 corresponds to the rotation period of the photoreceptor, the transfer belt, the fixing device, and the like (the amount of conveyance of the recording medium in the sub-scanning direction after one rotation) for occurrence of a precursor of a defect due to scratches on the photoreceptor. Interval) to store. When the interval in the sub-scanning direction is the same as one of the intervals stored in the period information storage unit 44, the classification unit 42 has the same point in the sub-scanning direction as the precursor of the point-like defect having the same position in the main scanning direction. The precursors of defects are presumed to have the same cause, and are classified into the same set. Here, the same position in the main scanning direction may include the case where the difference in position in the main scanning direction is within a predetermined range.

  The image selection unit 46 selects a read image to be stored from among a plurality of read images classified into the same set by classification by the classification unit 42. In the present embodiment, the image selection unit 46 selects a partial image to be stored from among a plurality of partial images included in the history information classified into the same set by the classification unit 42. For example, the image selection unit 46 selects a partial image having the highest degree of defect sign of defects from the partial images included in each piece of history information classified into the same set. Note that the image selection unit 46 may not select all the read images from the same set, and may select two or more read images.

  The storage control unit 48 controls to store at least the read image selected by the image selection unit 46. In the present embodiment, the storage control unit 48 stores the history information generated by the defect information generation unit 38 in the defect / defect precursor information storage unit 50 and the history information generated by the defect precursor information generation unit 40 as a defect. Store in the defect precursor information storage unit 50. However, the storage control unit 48 stores the partial image selected by the image selection unit 46 for the partial image in the history information generated by the defect precursor information generation unit 40 and is not selected by the image selection unit 46. The partial image is not stored.

  The storage control unit 48 may store the history information in the storage device 18, but may store it in a storage destination other than the storage device 18. For example, you may memorize | store in the memory | storage device of the memory | storage destination connected via the network which is not shown in figure.

  The output unit 52 outputs the history information stored in the defect / defect precursor information storage unit 50. In the present embodiment, the output unit 52 outputs a display to the input / output device 22. Note that the output format by the output unit 52 is not limited to display output, but may be other output, for example, output to another device via the communication IF 20.

  When the number of read images determined to exceed the threshold value by the defect sign determination unit 36 exceeds a predetermined number, the threshold value changing unit 54 sets the defect sign determination threshold value to a value that is looser than the set value. Change to In the present embodiment, when the number of history information generated by the defect precursor information generating unit 40 exceeds a predetermined number, the threshold changing unit 54 sets a defect precursor determination threshold value to a value that is already set. Change to a higher value.

  The threshold value changing unit 54 may change the threshold value determining unit 54 so as to increase the defect sign determining threshold value according to the number of read images determined to exceed the threshold value by the defect sign determining unit 36. In the present embodiment, the threshold value changing unit 54 changes the defect sign determination threshold value to increase according to the number of history information items generated by the defect sign information generating unit 40. Specifically, every time the number of history information exceeds a predetermined number provided in multiple stages, the threshold change unit 54 increases the defect sign determination threshold.

  The warning unit 56 warns when the difference between the defect determination threshold and the defect precursor determination threshold is within a predetermined range due to the change of the defect precursor determination threshold by the threshold changing unit 54. In the present embodiment, the warning unit 56 gives a warning to the input / output device 22 by performing a display output indicating that the difference between the defect determination threshold value and the defect sign determination threshold value is within a predetermined range. The warning method by the warning unit 56 is not limited to display output, but may be given by voice or may be notified to another device.

  FIG. 4 is a schematic diagram for explaining the history information stored by the storage control unit 48. FIG. 4A shows an example of the history information generated by the defect precursor information generation unit 40, and FIG. ) Shows an example of history information classified by the classification unit 42 and partial images selected by the image selection unit 46.

  As shown in FIG. 4A, when the defect sign information generation unit 40 determines that the read image has a quality defect sign by the defect sign determination unit 36, as the history information about the defect sign, Defect precursor ID that is identification information of history information, type of defect precursor, occurrence page number, X coordinate that is the occurrence position in the main scanning direction, Y coordinate that is the occurrence position in the sub-scanning direction, defect defect defect degree, Information consisting of a partial image of the precursor of the defect is generated. Note that the Y coordinate here is not the coordinate from the first page of the print job, but the coordinate on the page.

  As shown in FIG. 4B, the classification unit 42 classifies the history information generated as shown in FIG. 4A into several sets. For each classification, the classification ID that is the identification information of the classification, the type of precursor of the defect of the history information sorted into the classification, the aggregation number that is the number of history information sorted into the classification, and the classification The X coordinate of the history information, the representative image selected by the image selection unit 46 from the partial images included in the history information sorted into the classification, the degree of defect of the representative image, and the history constituting the classification The information is organized into information composed of pointers indicating the storage locations of the information and stored in the defect / defect precursor information storage unit 50.

  Further, history information constituting the classification is stored at the tip of the pointer. For example, for each piece of history information constituting the classification, the defect information ID, the Y coordinate, the relative position of the Y coordinate, the degree of failure of the defect precursor, and a pointer indicating the storage location of the next history information constituting the classification It is stored in the precursor information storage unit 50. The Y-coordinate relative position indicates a coordinate value from the first page of the print job, and can be calculated from the generated page number and the Y-coordinate, for example. Thus, not all the partial images are stored in the defect / defect precursor information storage unit 50, but the partial image selected as the representative image is stored.

Next, the operation of the inspection apparatus 8 will be described with reference to FIGS.
FIG. 5 is a flowchart showing an example of the operation of the inspection apparatus 8.

  In step 100 (S100), the read image acquisition unit 30 acquires a read image, and in step 102 (S102), the formed image acquisition unit 32 acquires a formed image corresponding to the read image acquired in step 100. .

  Next, in step 104 (S104), the defect determination unit 34 determines whether or not there is a defect in image formation quality of the image forming apparatus 6 for the read image acquired in step 100. In step 106 (S106), it is determined whether or not there is a defect. If there is a defect, the process proceeds to step 108 (S108), and the defect information generation unit 38 generates history information. The history information generated by the storage control unit 48 in (S110) is stored in the defect / defect precursor information storage unit 50.

  On the other hand, if it is determined in step 106 that there is no defect, the process proceeds to step 112 (S112), and the defect precursor determination unit 36 performs image formation of the image forming apparatus 6 on the read image acquired in step 100. Determine the presence or absence of a quality defect. In step 114 (S114), it is determined whether or not it is determined that there is a defect sign. If there is a defect sign, the process proceeds to step 116. If there is no defect sign, the process proceeds to step 128. .

  In step 116 (S116), the defect precursor information generation unit 40 generates history information. In step 118 (S118), it is determined whether or not the total number of generated history information exceeds a predetermined number. If it exceeds, the process proceeds to step 120. If not, the process proceeds to step 126.

  In step 120 (S120), the threshold value changing unit 54 changes the defect sign determination threshold value to a value higher than the already set value. Here, in step 122 (S122), it is determined whether or not the difference between the changed defect sign determination threshold and the defect determination threshold is within a predetermined range, and is within the predetermined range. In step 124 (S124), the warning unit 56 issues a warning. If it is not within the predetermined range, the process proceeds to step 126.

  In step 126 (S126), the storage process for the history information generated in step 116 is performed. Details of the processing in step 126 will be described with reference to the flowcharts of FIG.

  In step 128 (S128), it is determined whether or not there is a next page on which an image is formed by the print job. If there is a next page, the process returns to step 100 and the above-described processing is repeated. If there is no next page, the inspection of the image formed by the print job ends.

  FIG. 6 is a flowchart showing details of the processing of step 126 shown in FIG. Hereinafter, the process performed in step 126 will be described with reference to FIG.

  In step 200 (S200), the classification unit 42 includes information (Dk) indicating the type of defect precursor among the history information generated by the defect precursor information generation unit 40 in step 116, and the presence position (Xk) in the main scanning direction. ) To get.

  In step 202 (S202), the classification unit 42 acquires the number (num) of classification IDs of already classified information.

  In step 204 (S204), the classification unit 42 sets the value of the variable i to 0, and proceeds to step 206. In step 206 (S206), the num acquired in step 202 is compared with the value of the variable i. If the value of the variable i is greater than or equal to num, the process proceeds to step 208, and if the value of the variable i is less than num. Then, the process proceeds to step 210.

  In step 208 (S208), the classification unit 42 determines that the history information cannot be classified into an existing classification destination, and registers it as a new classification.

  On the other hand, in step 210 (S210), the classification unit 42 acquires information about the i-th classification destination (set). Specifically, the classification unit 42 acquires information (Dn) indicating the type of defect precursor of the history information classified as the classification destination, and the position (Xn) in the main scanning direction. Further, 1 is added to the value of the variable i.

  In step 212 (S212), it is determined whether or not the information (Dk) indicating the type of defect precursor acquired in step 200 is the same as the information (Dn) indicating the type of defect precursor acquired in step 210. If they are the same, the process proceeds to step 214; otherwise, the process returns to step 206.

  In step 214 (S214), it is determined whether or not the existence position (Xk) in the main scanning direction acquired in step 200 is the same as the existence position (Xn) in the main scanning direction acquired in step 210. If YES, the process proceeds to step 216. If not, the process returns to step 206.

  In step 216 (S216), it is determined whether the information (Dk) indicating the type of defect precursor acquired in step 200 is a precursor of a streak defect or a precursor of a dotted defect. If it is a precursor of a defect, the process proceeds to step 218. If it is a precursor of a point-like defect, the process proceeds to step 220.

  In step 218 (S218), processing (merging processing) for merging with the classification destination that is the information acquisition source in step 210 is performed as the history information of the precursor of the streak defect. Details of the processing in step 218 will be described with reference to the flowchart shown in FIG.

  On the other hand, in step 220 (S220), classification destination determination processing is performed for the precursor of the point-like defect. Details of the processing in step 220 will be described with reference to the flowchart shown in FIG.

  FIG. 7 is a flowchart showing details of the processing in step 220 shown in FIG. Hereinafter, the process performed in step 220 will be described with reference to FIG.

  In step 300 (S300), the classification unit 42 acquires the Y coordinate that is the presence position of the defect precursor in the sub-scanning direction from the history information generated by the defect precursor information generation unit 40 in step 116. In addition, the Y coordinate relative position (Yk) is calculated from the Y coordinate based on the occurrence page number of the precursor of the defect.

  In step 302 (S302), the classification unit 42 obtains the Y coordinate relative position (Yn) of the first history information among the history information constituting the classification (set) that is a candidate classification destination of the defect precursor. To do. Here, the classification that is a candidate for the classification destination is a classification from which information is acquired in step 210.

  In step 304 (S304), the classification unit 42 calculates a distance Lk between the precursor of the defect to be classified and the precursor of the defect whose Y coordinate relative position is acquired in step 302 by Lk = Yk−Yn.

  In step 306 (S306), the classification unit 42 obtains the number (num ′) of rotating members whose information on the period is stored in the period information storage unit 44, and in step 308 (S308), the value of the variable j Is set to 0.

  In step 310 (S310), the classification unit 42 compares num ′ acquired in step 306 with the value of variable j. If the value of variable j is equal to or greater than num ′, the classification unit 42 proceeds to step 312. If the value of is less than num ′, the process proceeds to step 314.

  In step 312 (S312), the classification unit 42 determines that the history information cannot be classified into an existing classification destination, and registers it as a new classification.

  On the other hand, in step 314 (S314), the classification unit 42 acquires information Ln about the cycle of the j-th rotation member among the rotation members whose information about the cycle is stored in the cycle information storage unit 44.

  In step 316 (S316), the classification unit 42 determines whether or not the difference between Lk calculated in step 304 and Ln acquired in step 314 is within a predetermined range Th, and is within Th. In such a case, it is determined that the interval is the same, and the process proceeds to step 318. If the distance exceeds Th, the process returns to step 310.

  In step 318, processing (merging processing) for merging into the classification destination is performed as history information of the precursors of the point-like defects. Details of the processing in step 318 will be described with reference to the flowchart shown in FIG.

  FIG. 8 is a flowchart showing the details of step 218 shown in FIG. 6 and step 318 shown in FIG. Hereinafter, the processes performed in step 218 and step 318 will be described with reference to FIG.

  In step 400 (S400), the image selection unit 46 acquires the defect degree Gk of the precursor of the defect to be classified, and in step 402 (S402), the image selection unit 46 determines the maximum failure of the precursor of the defect of the classification destination. The degree Gmax is acquired.

  In step 404 (S404), the image selection unit 46 compares the defect degree Gk acquired in step 400 with the defect degree Gmax acquired in step 402, and determines whether Gk exceeds Gmax. If not, the process proceeds to step 406, and if exceeded, the process proceeds to step 408.

  In step 406 (S406), the image selection unit 46 discards the partial image that is a precursor of the defect to be merged instead of being stored.

  On the other hand, in step 408 (S408), the value of the information Gmax indicating the maximum failure degree of the classification destination is updated to Gk.

  In step 410 (S410), the image selection unit 46 selects a partial image of a precursor of a defect to be merged as a representative image to be classified, and the storage control unit 48 replaces the stored representative image. As a result, the old representative image is discarded.

  In step 412 (S412), the storage control unit 48 adds the history information of the precursor of the defect to be merged as the top data of the history information group of the classification destination. Add and finish.

  In the embodiment described above, the classification unit 42 and the image selection unit 46 process the history information about the defect precursor, but the defect classification information also performs the same classification and selection of the partial image to be recorded. May be. In the above description, inspection of an image formed by an electrophotographic image forming apparatus has been described. However, the image forming system is not limited to this, and for example, inspection of an image formed by an inkjet image forming apparatus is performed. The present invention can also be applied to.

2 Image forming system 4 Paper feeding device 6 Image forming device 8 Inspection device 10 Post-processing device 12 Image reading device 30 Read image acquiring unit 32 Formed image acquiring unit 34 Defect determining unit 36 Defect precursor determining unit 38 Defect information generating unit 40 Defect Precursor information generation unit 42 Classification unit 44 Period information storage unit 46 Image selection unit 48 Storage control unit 50 Defect / defect precursor information storage unit 52 Output unit 54 Threshold change unit 56 Warning unit

Claims (11)

Read image acquisition means for acquiring a read image obtained by reading a recording medium on which image formation has been performed;
Whether the difference between the read image acquired by the read image acquisition means and the image formed on the recording medium exceeds a first threshold value for determining the presence or absence of an image formation defect First determination means for determining whether or not,
The difference between the read image acquired by the read image acquisition means and the formed image used in image formation on the recording medium is greater than the first threshold value for determining the presence or absence of a precursor of a defect. A second determination means for determining whether or not a lower second threshold value is exceeded;
A storage control unit that controls to store the read image acquired by the read image acquisition unit when the first determination unit or the second determination unit determines that the threshold value is exceeded. The inspection apparatus according to claim 1, wherein the second determination unit sets an image area wider than an image area to be determined by the first determination unit. Classification means for classifying the read image determined to exceed the threshold by the second determination means;
Image selection means for selecting a read image to be stored by the storage control means among a plurality of read images classified into the same set by classification by the classification means; and
The inspection apparatus according to claim 1, wherein the storage control unit performs control so as to store a read image selected by the image selection unit. The inspection apparatus according to claim 3, wherein the image selection unit selects a read image including a precursor portion of a defect having the highest degree of defect among a plurality of read images classified into the same set by classification by the classification unit. The inspection apparatus according to claim 3 or 4, wherein the classification means classifies the defect according to a position where a precursor part of a defect exists in the main scanning direction. If the difference between the existence interval in the sub-scanning direction of the precursor portions of the plurality of defects and the interval predetermined for each cause causing the defect precursor is within a predetermined range, the classification means The inspection apparatus according to claim 5, wherein each read image including a precursor portion is classified into the same set. When the number of read images determined to exceed the threshold by the second determination unit exceeds a predetermined value, the second threshold is changed to a value higher than the set value. The inspection apparatus according to claim 1, further comprising a threshold value changing unit. Warning means for warning when the difference between the first threshold value and the second threshold value is within a predetermined range;
The inspection apparatus according to claim 7, wherein the threshold value changing unit increases the value of the second threshold value according to the number of read images determined to exceed the threshold value by the second determination unit. Read image acquisition means for acquiring a read image obtained by reading a recording medium on which image formation has been performed;
A determination unit that determines whether or not a difference between a read image acquired by the read image acquisition unit and a formed image used in image formation on the recording medium exceeds a predetermined threshold;
Classification means for classifying the read image determined to exceed the threshold by the determination means;
Image selecting means for selecting a read image to be stored among a plurality of read images classified into the same set by classification by the classification means;
And a storage control unit that controls to store the read image selected by the image selection unit. A difference between a read image obtained by reading a recording medium on which image formation has been performed and an image to be formed used for image formation on the recording medium is a first for determining whether there is a defect in image formation. A first determination step for determining whether or not a threshold value is exceeded;
A second threshold value that is lower than the first threshold value for determining whether or not a difference between the read image and a formed image used in image formation on the recording medium is a sign of a defect. A second determination step for determining whether or not
A program that causes a computer to execute a storage control step of controlling to store the read image when it is determined in the first determination step or the second determination step that a threshold value is exceeded. Determination to determine whether or not the difference between the read image obtained by reading the recording medium on which the image has been formed and the image to be formed used for image formation on the recording medium exceeds a predetermined threshold value Steps,
A classification step of classifying the read image determined to exceed the threshold in the determination step;
An image selection step of selecting a read image to be stored among a plurality of read images classified into the same set by classification in the classification step;
And a storage control step for controlling the selected read image to be stored.

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