Inspection device, image forming system, abnormality detection method, and program

Abstract

To provide an inspection device, an image forming system, an abnormality detection method, and a program with which it is possible to accurately detect an abnormality in a recording medium on which an image is formed.SOLUTION: An inspection device comprises: a grounding information acquisition unit that acquires pre-printing grounding information of a recording medium before printing and post-printing grounding information of the recording medium after printing; and an abnormality determination unit that determines the presence or absence of an abnormality in the recording medium after printing on the basis of the pre-printing grounding information and the post-printing grounding information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an inspection apparatus, an image forming system, an abnormality detection method, and a program. [Background technology]

[0002] Conventionally, an image forming system is known in which an inspection unit is arranged downstream of an image forming device that forms an image on a recording medium (see, for example, Patent Document 1). The inspection unit inspects the recording medium on which the image is formed for abnormalities.

[0003] In such image forming systems, paper with a texture such as embossed paper is sometimes used as the recording medium. When embossed paper is used as the recording medium, the texture of the paper is read as a background pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-194598 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when embossed paper with unevenness is used as the recording medium, toner may not adhere properly to the paper when forming an image on the paper, and may scatter into the background area other than the print area where the image is formed. In such cases, it is difficult to determine whether the pattern on the background is due to the unevenness of the paper or to scattered toner. Therefore, conventional image forming systems have the problem of being unable to properly detect abnormalities caused by toner scattering, etc.

[0006] An object of the present disclosure is to provide an inspection device, an image forming system, an abnormality detection method, and a program that can accurately detect abnormalities in a recording medium on which an image is formed. [Means for solving the problem]

[0007] The inspection device according to the present disclosure includes: a base information acquisition unit that acquires pre-printing base information of a recording medium before printing and post-printing base information of the recording medium after printing; an abnormality determination unit that determines whether or not there is an abnormality in the recording medium after printing based on the pre-printing base information and the post-printing base information; Equipped with.

[0008] The image forming system according to the present disclosure includes: a reading device that reads pre-printing base information from the conveyed recording medium before printing; an image forming device that forms an image on the recording medium conveyed from the reading device; The above inspection device, Equipped with.

[0009] The anomaly detection method according to the present disclosure includes: Acquire pre-printing base information of the recording medium before printing and post-printing base information of the recording medium after printing; Based on the pre-printing base information and the post-printing base information, it is determined whether or not there is an abnormality in the recording medium after printing.

[0010] The program according to the present disclosure is The above-described anomaly detection method is executed by a computer. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to accurately detect abnormalities in a recording medium on which an image is formed. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an image forming system according to the present embodiment. [Figure 2] FIG. 2 is a block diagram showing the main parts of a control system of the image forming system according to this embodiment. [Figure 3] FIG. 3 is a functional block diagram illustrating an example of the configuration of the control unit in FIG. [Figure 4] FIG. 4 is a schematic diagram for explaining how to read a paper sheet. [Figure 5] FIG. 5 is a schematic diagram for explaining a state in which toner is scattered on a sheet of paper. [Figure 6] FIG. 6 is a schematic diagram for explaining a first example of a color distribution range in the background region of a sheet. [Figure 7] FIG. 7 is a schematic diagram for explaining a second example of the color distribution range in the background region of the paper. [Figure 8] FIG. 8 is a schematic diagram for explaining a third example of the color distribution range in the background region of the paper. [Figure 9] FIG. 9 is a schematic diagram for explaining a fourth example of the color distribution range in the background region of the paper. [Figure 10] FIG. 10 is a flowchart showing an example of the flow of the abnormality detection process according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments, and various modifications are possible without departing from the spirit of the present disclosure. In addition, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

[0014] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. An image forming system according to the present embodiment is capable of forming an image on paper (recording medium) such as a sheet of paper. Note that, although the following description will be given taking as an example a case where paper is used as the recording medium, the recording medium is not limited to paper, and other media such as cloth may also be used.

[0015] [Configuration of image forming system 1] Fig. 1 is a schematic diagram showing an example of the configuration of an image forming system 1 according to this embodiment. Fig. 2 is a block diagram showing the main parts of a control system of the image forming system 1 according to this embodiment. As shown in Fig. 1, the image forming system 1 is configured to include an image forming apparatus 100, a paper feed unit 200, a reading unit 300, an inspection unit 500, and a paper discharge unit 400.

[0016] Image forming apparatus 100 is an intermediate transfer type color image forming apparatus that utilizes electrophotographic process technology. That is, image forming apparatus 100 forms an image by primarily transferring toner images of each color (CMYK) formed on a photosensitive member to an intermediate transfer member, superimposing the four color toner images on the intermediate transfer member, and then secondary transferring the images onto paper. CMYK stands for cyan (C), magenta (M), yellow (Y), and black (K).

[0017] The image forming apparatus 100 employs a tandem system in which photosensitive elements corresponding to the four colors CMYK are arranged in series in the direction of travel of the intermediate transfer body, and toner images of each color are transferred sequentially to the intermediate transfer body in a single step.

[0018] As shown in FIG. 2, the image forming system 1 includes an image processing unit 10, an image forming unit 20, a fixing unit 30, a paper transport unit 40, an operation display unit 50, a communication unit 71, a memory unit 72, a control unit 600, a paper feed unit 200, a reading unit 300, an inspection unit 500, and a paper discharge unit 400.

[0019] The image processing unit 10 includes a circuit for performing image processing on input image data according to initial settings or user settings, etc. The image forming unit 20 is controlled based on the image data that has undergone image processing.

[0020] The image forming section 20 includes an image forming unit 21, an intermediate transfer unit 22, and a secondary transfer unit 23. The image forming unit 21 forms an image using color toners of each color component based on image data from the image processing section 10. For example, the image is formed using color toners of each color component of Y (yellow), M (magenta), C (cyan), and K (black).

[0021] The image forming unit 21 has, for each color, an exposure device, a developing device, a photosensitive drum, a charging device, a drum cleaning device, etc. Known technologies can be used for the exposure device, developing device, photosensitive drum, charging device, and drum cleaning device, so detailed explanations will be omitted here.

[0022] The intermediate transfer unit 22 includes an intermediate transfer belt and other components. The intermediate transfer belt is looped and stretched around multiple support rollers, and travels in the direction of arrow A. The support rollers include a backup roller, a primary transfer roller, a drive roller, and other rollers, but these are not shown here. The intermediate transfer belt is pressed against the photosensitive drum, thereby transferring the toner image from the photosensitive drum to the intermediate transfer belt.

[0023] The intermediate transfer unit 22 may be configured to include a belt cleaning device having a plate-shaped belt cleaning blade or the like that slides against the surface of the intermediate transfer belt. The belt cleaning device removes residual toner and the like that remains on the surface of the intermediate transfer belt after the secondary transfer.

[0024] The secondary transfer unit 23 includes a secondary transfer roller, etc. The secondary transfer roller is pressed against the intermediate transfer belt, thereby forming a secondary transfer nip between the intermediate transfer belt and the secondary transfer roller.

[0025] In the secondary transfer unit 23, when a sheet of paper is transported to the secondary transfer nip, the toner images of each color carried on the intermediate transfer belt are transferred onto the sheet of paper at once. The sheet of paper onto which the toner images have been transferred is transported toward the fixing unit 30 by the secondary transfer roller.

[0026] The secondary transfer unit 23 may be a belt-type secondary transfer unit having a secondary transfer belt stretched over a plurality of support rollers, instead of a roller-type secondary transfer unit having a secondary transfer roller or the like.

[0027] The fixing unit 30 includes a fixing roller and a pressure roller. The fixing roller is heated to a predetermined fixing temperature, and the pressure roller forms a fixing nip between the fixing roller and the pressure roller, which sandwiches and transports the paper. In the fixing unit 30, the toner image is fixed to the paper by applying heat and pressure to the paper, which has been secondarily transferred, in the fixing nip.

[0028] The paper transport unit 40 includes a transport path unit 41. The transport path unit 41 is configured with, for example, a path for transporting paper, multiple transport rollers, and a drive motor for driving the transport rollers to rotate. The transport path unit 41 transports paper supplied from the paper feed unit 200 to the secondary transfer unit 23 and the fixing unit 30, and then transports the paper to the paper discharge unit 400.

[0029] In the transport path section 41, a pair of registration rollers 41a is provided upstream of the secondary transfer unit 23 in the paper transport direction D. The pair of registration rollers 41a adjusts the transport timing and direction (angle) of the paper to be transported to the secondary transfer unit 23.

[0030] The operation display unit 50 is configured, for example, with a liquid crystal display (LCD) with a touch panel, and functions as a display unit and an operation unit. The display unit displays various operation screens, image status displays, and the operating status of each function in accordance with a display control signal input from the control unit 600. The operation unit has various operation keys such as a numeric keypad and a start key, accepts various input operations by the user, and outputs operation signals to the control unit 600.

[0031] The paper feed unit 200 is disposed upstream of the image forming apparatus 100 in the paper transport direction D, and is connected to the image forming apparatus 100. The paper feed unit 200 corresponds to the "supply device" of the present disclosure.

[0032] Paper feed unit 200 has multiple paper feed trays 201, 202, and 203, and each of paper feed trays 201, 202, and 203 stores sheets of paper (standard paper or special paper) identified based on basis weight, size, etc., according to a preset type. Based on an instruction from image forming apparatus 100, paper feed unit 200 supplies the specified paper to image forming apparatus 100.

[0033] The reading unit 300 is disposed between the paper feed unit 200 and the image forming device 100, and is connected to the paper feed unit 200 on the upstream side and to the image forming device 100 on the downstream side in the paper transport direction D. The reading unit 300 corresponds to the "reading device" of the present disclosure.

[0034] Reading unit 300 has sensors 301 and 302 that read paper transported from paper feed unit 200. Sensor 301 is located above the path along which paper is transported, facing the paper being transported, and is configured to read the front (upper) side of the paper being transported. Sensor 302 is located below the path along which paper is transported, facing the paper being transported, and is configured to read the back (lower) side of the paper being transported.

[0035] For example, CCDs (Charge Coupled Devices) or CISs (Contact Image Sensors) are used as sensors 301 and 302. Furthermore, for sensors 301 and 302, line sensors that extend across a width equal to or greater than the width of the paper (the width in the direction perpendicular to the paper conveyance direction D), such as line scanners or line sensor cameras, are used.

[0036] The sensors 301 and 302 acquire paper information, which is information related to paper. As paper information, the sensors 301 and 302 acquire, for example, paper size (paper width, paper length, etc.) and paper position. In the present embodiment, the sensors 301 and 302 also acquire, as one type of paper information, background information including color information such as the color and brightness of the paper before an image is formed.

[0037] Here, as an example, the reading unit 300 is configured to have sensors 301 and 302 that read both sides (front and back) of the paper, but this is not limited to this, and it may also be configured to have, for example, only sensor 301 that reads one side (front) of the paper.

[0038] The paper discharge unit 400 is disposed downstream of the inspection unit 500 in the paper conveying direction D, and is connected to the image forming apparatus 100 via the inspection unit 500. The paper discharge unit 400 has a paper discharge tray 401 and a purge tray 402, and discharges conveyed paper to the paper discharge tray 401 or the purge tray 402.

[0039] Paper output tray 401 outputs paper on which an image has been formed by image forming apparatus 100. Purge tray 402 outputs paper whose paper size does not satisfy predetermined conditions as a result of reading the paper size by reading unit 300. For example, if the paper size read by reading unit 300 does not satisfy predetermined conditions, paper output unit 400 may output paper on which an image has not been formed by image forming apparatus 100 from purge tray 402, as indicated by the dashed-dotted arrow in FIG.

[0040] The inspection unit 500 is disposed between the image forming device 100 and the paper discharge unit 400 in the paper transport direction D. The inspection unit 500 is connected to the image forming device 100 on the upstream side and to the paper discharge unit 400 on the downstream side. The inspection unit 500 corresponds to the "inspection device" of the present disclosure.

[0041] The inspection unit 500 inspects whether or not there is an abnormality in the paper on which an image has been formed by the image forming apparatus 100. The inspection unit 500 has sensors 501 and 502 that read the paper conveyed from the image forming apparatus 100.

[0042] Sensor 501 is arranged above the path along which paper is transported, facing the paper being transported, and is configured to read the front (upper) side of the paper being transported. Sensor 502 is arranged below the path along which paper is transported, facing the paper being transported, and is configured to read the back (lower) side of the paper being transported.

[0043] As sensors 501 and 502, for example, a CCD or CIS is used, similar to sensors 301 and 302 of reading unit 300. As sensors 501 and 502, a line sensor extending across a width equal to or greater than the width of the paper (width in a direction perpendicular to paper conveyance direction D), for example, a line scanner or line sensor camera, is used. Sensors 501 and 502 acquire background information of the paper on which an image is formed.

[0044] The sensors 501 and 502 acquire background information, which includes color information such as the color and brightness of the paper on which the image is formed, as a type of paper information. Note that, here, the inspection unit 500 is configured to have sensors 501 and 502 that read both sides (front and back) of the paper, as an example, but is not limited to this, and may be configured to have only the sensor 501 that reads one side (front) of the paper, for example.

[0045] The control unit 600 is connected to the above-mentioned image processing unit 10, image forming unit 20, fixing unit 30, paper transport unit 40, operation display unit 50, communication unit 71, memory unit 72, paper feed unit 200, reading unit 300, inspection unit 500, and paper discharge unit 400. The control unit 600 issues various instructions to each of these units and executes predetermined processes.

[0046] The control unit 600 includes a CPU (Central Processing Unit) 601, a ROM (Read Only Memory) 602, and a RAM (Random Access Memory) 603. The CPU 601 reads a program corresponding to the processing content from the ROM 602, loads it into the RAM 603, and centrally controls the operation of each block of the image forming system 1 in cooperation with the loaded program. At this time, various data such as an LUT (Look Up Table) stored in the storage unit 72 is referenced. The storage unit 72 is configured, for example, with a non-volatile semiconductor memory (so-called flash memory) or a hard disk drive.

[0047] The control unit 600 transmits and receives various data to and from an external device (for example, a personal computer) connected to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network) via the communication unit 71. The control unit 600 receives, for example, image data transmitted from an external device and forms an image on paper based on this image data (input image data). The communication unit 71 is configured, for example, by a communication control card such as a LAN card.

[0048] In the first embodiment, the control unit 600 performs an abnormality detection process to detect abnormalities in the recording medium on which an image is formed, based on the paper substrate information before and after printing. Details of the abnormality detection process will be described later.

[0049] Fig. 3 is a functional block diagram showing an example of the configuration of the control unit 600 in Fig. 2. As shown in Fig. 3, the control unit 600 has a background information acquisition unit 611, a color information extraction unit 612, a distribution range determination unit 613, a comparison and judgment unit 614, and a storage unit 615.

[0050] The substrate information acquisition unit 611 acquires pre-printing substrate information from the sensors 301 and 302 of the reading unit 300. The substrate information acquisition unit 611 also acquires post-printing substrate information from the sensors 501 and 502 of the inspection unit 500.

[0051] The pre-printing substrate information is substrate information of the paper before printing, read by sensors 301 and 302 of the reading unit 300. The post-printing substrate information is substrate information of the paper after printing, read by sensors 501 and 502 of the inspection unit 500.

[0052] The color information extraction unit 612 extracts pre-printing color information from the pre-printing base information. The color information extraction unit 612 also extracts post-printing color information from the post-printing base information. The pre-printing color information is information about the color in the base area of ​​the paper before printing, and is included in the pre-printing base information. The pre-printing color information includes, for example, paper color and brightness information. The post-printing color information is information about the color in the base area of ​​the paper after printing, and is included in the post-printing base information. The post-printing color information includes, for example, paper color and brightness information.

[0053] The distribution range determination unit 613 determines a pre-printing color distribution range based on the pre-printing color information. Also, the distribution range determination unit 613 determines a post-printing color distribution range based on the post-printing color information. The pre-printing color distribution range is the color distribution range in the background area of ​​the paper before printing. The post-printing color distribution range is the color distribution range in the background area of ​​the paper after printing.

[0054] The comparison and judgment unit 614 judges whether or not there is an abnormality in the paper on which the image is formed, based on the pre-print color distribution range and the post-print color distribution range. For example, the comparison and judgment unit 614 compares the pre-print color distribution range with the post-print color distribution range. Then, the comparison and judgment unit 614 judges whether or not the respective color distribution ranges match. The comparison and judgment unit 614 corresponds to the "abnormality judgment unit" in this disclosure.

[0055] The storage unit 615 stores various data used by each unit of the control unit 600. For example, the storage unit 615 stores pre-printing base information read by the reading unit 300.

[0056] [Operation of image forming system 1] The operation of image forming system 1 having the above configuration according to Embodiment 1 will be described. In image forming system 1, when an image is formed on paper, which is a recording medium, the paper is stored in paper feed trays 201, 202, and 203 of paper feed unit 200. The paper fed from paper feed unit 200 is then transported to reading unit 300, where pre-printing base information including pre-printing color information of the paper is read, and the paper is then transported to image forming apparatus 100.

[0057] When reading background information from a sheet, the reading unit 300 extracts the area outside the print area, excluding the print area where the image is formed, as a background area, and reads the background information from the background area. The print area and background area can be extracted using, for example, a known method.

[0058] If the print area is set in advance, the reading unit 300 may extract the background area based on the setting of the print area. If the print area is not set in advance, the reading unit 300 may read background information from the entire area of ​​the paper, for example.

[0059] The paper transported to image forming apparatus 100 undergoes image formation (hereinafter referred to as "printing") in image forming apparatus 100, and is then transported to inspection unit 500. The paper transported to inspection unit 500 undergoes an abnormality detection process, and the paper is inspected for abnormalities after printing. After inspection, the paper is transported to paper discharge unit 400.

[0060] [Anomaly detection processing] Next, the abnormality detection process according to this embodiment will be described.

[0061] As explained in the Background Art section, when printing is performed using paper with a texture such as embossed paper as a recording medium, the texture of the paper is read as a base (pattern). Figure 4 is a schematic diagram for explaining paper reading. As shown in Figure 4, when the surface of embossed paper with a texture is read before printing, the texture is read as a base pattern.

[0062] On the other hand, when embossed paper is used, toner may not completely adhere to the paper and may scatter into the background area when an image is formed on the paper due to the shape of the photosensitive drum or the distribution of charge in the image forming apparatus 100. Figure 5 is a schematic diagram for explaining the state of toner scattered on the paper. As shown in Figure 5, when the surface of the embossed paper is read after printing, stains may occur due to toner scattering into the background area, as indicated by the dashed circle.

[0063] When toner is scattered in the background area in this way, it is difficult to determine whether the pattern in the background area is due to the unevenness of the paper or the scattered toner. Therefore, in this embodiment, the background information of the paper before printing is read in advance, and an abnormality detection process is performed to accurately detect abnormalities in the paper on which an image has been formed based on the background information read in advance before printing and the background information read after printing.

[0064] (Color distribution range of the background area) The abnormality detection process focuses on the color distribution range of the paper before and after printing. Here, we consider the color distribution range in the Lab color space in the background area of ​​the paper before and after printing. The Lab color space is a color system with a dimension "L" that indicates lightness and dimensions "a" and "b" that indicate hue and saturation.

[0065] For example, consider the case where white embossed paper is scanned before printing. In this case, the background pattern in the background area, which is caused by the unevenness of the embossed paper, is expressed in gradations of white and black. Therefore, the pre-print color distribution range, which is the color distribution range of the background before printing, is based on color information expressed in gradations of white and black.

[0066] In contrast, if toner is scattered into the base region during printing, the post-printing color distribution range, which is the color distribution range of the base region, will differ from the pre-printing color distribution range. Specifically, the post-printing color distribution range is based on color information corresponding to the color of the scattered toner, in addition to color information indicating the pre-printing color distribution range. In other words, if toner is scattered into the base region, the post-printing color distribution range will have a distribution that deviates from the pre-printing color distribution range.

[0067] Fig. 6 is a schematic diagram for explaining a first example of a color distribution range in the background region of paper. Fig. 6 shows the Lab color space. As shown in Fig. 6, the pre-printing color distribution range, which is the color distribution range of the background region of white embossed paper before printing, is formed on the L axis in the Lab color space.

[0068] Figure 6 shows the pre-printing color distribution range in the background area of ​​the paper before printing when printing on white embossed paper, and the position in the Lab color space of the toner scattered during printing. The toner scattered in the background area is located at coordinates different from those of the pre-printing color distribution range.

[0069] In this way, if an abnormality such as toner scattering occurs, the color distribution range of the background area will be different. Therefore, by comparing the color distribution range of the background area before and after printing, it is possible to detect whether or not there is an abnormality in the paper on which the image is formed.

[0070] (When the toner lightness L is high) However, when the lightness L of the scattered toner is high, the color becomes closer to white. Therefore, when white paper is used as the recording medium, the scattered toner becomes difficult to visually distinguish from the background pattern. Therefore, when the lightness L of the toner is high, even if the distribution based on the toner color information is outside the pre-printing color distribution range, it may not be determined to be abnormal.

[0071] Fig. 7 is a schematic diagram illustrating a second example of the color distribution range in the background region of paper. Fig. 7 shows the pre-print color distribution range and the position in the Lab color space of the toner scattered during printing. As shown in Fig. 7, in this example, the lightness L of the scattered toner is higher than that of the pre-print color distribution range.

[0072] (When the toner color is close to the base color) Furthermore, for example, if the color of the scattered toner is close to the color of the background area, it becomes difficult to visually distinguish the scattered toner from the background pattern. In this case, the pre-printing color distribution range may be set to a range wider than the actual pre-printing color distribution range.

[0073] 8 is a schematic diagram for explaining a third example of the color distribution range in the background region of the paper, which shows the actual pre-printing color distribution range and the pre-printing color distribution range that is set to a wider range.

[0074] By making the pre-print color distribution range wider than the actual range in this way, scattering of toner, which is difficult to visually distinguish, is not detected as an abnormality.

[0075] (If the paper color is other than white) If the color of the paper is different from the above-mentioned "white," the pre-print color distribution range of the paper is formed at a position different from that on the L axis.

[0076] Fig. 9 is a schematic diagram for explaining a fourth example of the color distribution range in the background region of the paper. Fig. 9 shows the pre-printing color distribution range when the paper as the recording medium is green. As shown in Fig. 9, when the paper is green, the pre-printing color distribution range is formed in a position different from when the paper is white.

[0077] In this way, even if the paper is not white, such as green, by comparing the color distribution ranges before and after printing as described above, it is possible to detect whether or not there is an abnormality in the paper on which the image is formed.

[0078] (Processing flow) 10 is a flowchart showing an example of the flow of the abnormality detection process according to this embodiment. The flowchart shown in FIG.

[0079] In step S1, the base information acquisition unit 611 of the control unit 600 acquires pre-printing base information before printing on paper. The pre-printing base information is, for example, read by the sensors 301 and 302 of the reading unit 300 and supplied to the control unit 600. The acquired pre-printing base information is stored in the memory unit 615.

[0080] In step S2, the color information extraction unit 612 reads the pre-printing base information from the storage unit 615. Then, the color information extraction unit 612 extracts pre-printing color information from the read pre-printing base information. In step S3, the distribution range determination unit 613 determines a pre-printing color distribution range based on the pre-printing color information extracted by the color information extraction unit 612.

[0081] In step S4, the base information acquisition unit 611 acquires post-printing base information after printing on paper. In step S5, the color information extraction unit 612 extracts post-printing color information from the post-printing base information acquired by the base information acquisition unit 611. In step S6, the distribution range determination unit 613 determines a post-printing color distribution range based on the post-printing color information extracted by the color information extraction unit 612.

[0082] Next, in step S7, the comparison and judgment unit 614 compares the pre-printing color distribution range determined in step S3 with the post-printing color distribution range determined in step S6, and judges whether the two color distribution ranges match.

[0083] If the comparison shows that the two color distribution ranges match (step S7: Yes), the comparison and judgment unit 614 determines in step S8 that there is no abnormality in the printed image. On the other hand, if the two color distribution ranges do not match (step S7: No), the comparison and judgment unit 614 determines in step S9 that there is an abnormality in the printed image.

[0084] In this abnormality detection process, for example, the reading unit 300 reads the pre-printing background information of the paper every time a paper is fed from the paper feed unit 200. That is, the background information acquisition unit 611 of the control unit 600 acquires new pre-printing background information for each paper.

[0085] Note that the acquisition of pre-printing background information is not limited to this example. For example, when the paper used has different specifications, the reading unit 300 and the background information acquisition unit 611 may read new pre-printing background information and supply it to the background information acquisition unit 611. Specifically, when the state of the paper feed unit 200 changes, for example, when the type of paper stored in the paper feed trays 201, 202, and 203 of the paper feed unit 200 changes, the reading unit 300 reads the pre-printing background information of the transported paper and supplies it to the background information acquisition unit 611.

[0086] Furthermore, for example, if the paper is the same, the background information acquisition unit 611 may reuse the pre-printing background information stored in the storage unit 615. In other words, the background information acquisition unit 611 may acquire the same pre-printing background information from the storage unit 615 until the type of paper is changed.

[0087] As described above, in the image forming system 1 according to the present embodiment, pre-printing substrate information and post-printing substrate information are acquired. Then, based on the pre-printing substrate information and post-printing substrate information, it is determined whether or not there is an abnormality in the recording medium after printing. If an abnormality occurs in the recording medium after printing, the state of the substrate of the recording medium changes. Therefore, by determining whether or not there is an abnormality based on the substrate information before and after printing in this manner, it is possible to accurately detect abnormalities in the printed recording medium. [Explanation of symbols]

[0088] 1. Image forming system 10 Image processing section 20 Image forming unit 21 Image forming unit 22 Intermediate transfer unit 23 Secondary transfer unit 30 Fixing unit 40 Paper transport section 41 Conveying path section 41a Registration roller pair 50 Operation display section 71 Communications Department 72 Memory section 100 Image forming device 200 Paper feed section 201, 202, 203 paper trays 300 Reading unit 301, 302 sensors 400 Paper output section 401 Paper output tray 402 Purge Tray 500 Inspection Department 501, 502 sensors 600 control section 601 CPU 602 ROM 603 RAM 611 Base Information Acquisition Unit 612 Color information extraction section 613 Distribution Range Determination Unit 614 Comparative Judgment Department 615 Storage section

Claims

1. a base information acquisition unit that acquires pre-printing base information of a recording medium before printing and post-printing base information of the recording medium after printing; an abnormality determination unit that determines whether or not there is an abnormality in the recording medium after printing based on the pre-printing base information and the post-printing base information; An inspection device comprising:

2. a distribution range determination unit that determines a pre-printing color distribution range of the recording medium before printing based on the pre-printing base information, and determines a post-printing color distribution range of the recording medium after printing based on the post-printing base information, The abnormality determination unit determining whether or not there is an abnormality in the recording medium after printing based on the difference between the pre-printing color distribution range and the post-printing color distribution range; The inspection device according to claim 1 .

3. The distribution range determination unit determining the pre-printing color distribution range to be wider than the actual color distribution range based on the pre-printing base information; The inspection device according to claim 2 .

4. a reading device that reads pre-printing base information from the conveyed recording medium before printing; an image forming device that forms an image on the recording medium conveyed from the reading device; The inspection device according to claim 1 ; An image forming system comprising:

5. The reading device is reading the pre-printing base information every time the recording medium is supplied; The image forming system according to claim 4 .

6. The printing apparatus further includes a supply device that supplies the recording medium before printing to the reading device, The reading device is reading the pre-printing substrate information every time the state of the supply device changes; The image forming system according to claim 4 .

7. The inspection device includes: Further, a storage unit for storing the pre-printing base information is provided. The abnormality determination unit When the conveyed recording medium is the same recording medium, the pre-printing base information stored in the storage unit is used. The image forming system according to claim 4 .

8. The reading device is extracting a print area and a background area from the recording medium; The inspection device includes: determining whether or not there is an abnormality in the recording medium in the background area; The image forming system according to claim 4 .

9. The inspection device includes: determining whether or not there is an abnormality in the recording medium with respect to the background area; The image forming system according to claim 8 .

10. Acquire pre-printing base information of the recording medium before printing and post-printing base information of the recording medium after printing; determining whether or not there is an abnormality in the recording medium after printing based on the pre-printing base information and the post-printing base information; Anomaly detection methods.

11. A program that causes a computer to execute the anomaly detection method according to claim 10.

Images