JP7537253B2 - Inspection device and image forming system - Google Patents

Description

The present invention relates to an inspection device that detects the conveyance state of recording material, and an image forming system that includes this inspection device.

In an image forming apparatus, recording materials are transported from a paper feed unit along a transport path to an image forming unit. In an image forming apparatus having a paper feed unit that automatically feeds recording materials, it is necessary to separate the recording materials one by one and transport them to the image forming unit. Even if the performance of the separation mechanism in the paper feed unit is improved, multiple feeding, in which multiple sheets of recording materials are stacked and transported at one time, occurs.
When a double feed occurs during the conveyance of recording materials, there is a possibility that the recording materials may become clogged during conveyance, i.e., a so-called jam may occur. Even if the recording materials can be conveyed without jamming, if an image is formed on the recording materials in the double-fed state, the output may be different from what the user intended. In view of this, an image forming apparatus has been proposed that has a detection sensor such as an optical element or an ultrasonic element for detecting the double feed on the conveyance path between the paper feed unit and the image forming unit (see, for example, Patent Document 1 and Patent Document 2).

Japanese Patent Application Publication No. 9-142699 Japanese Patent Application Publication No. 6-183605

However, in an image forming device with the above configuration, although it can detect double feeding of recording materials using a detection sensor, it cannot grasp the conveyance state of the recording materials, such as the amount of overlap between the double-fed recording materials or which recording material is located forward in the conveyance direction.

To solve the above-mentioned problems, the present invention provides an inspection device and an image forming system capable of detecting the transport state of overlapping recording materials.

The inspection device of the present invention includes a reading unit that reads a recording material being transported on a transport path and generates read image data of the recording material, and a control unit that detects the transport state of the recording material based on the read image data. The control unit has an image acquisition unit that acquires the read image data read by the reading unit, an analysis unit that analyzes the read image data acquired by the image acquisition unit and acquires image information of the recording material, and a detection unit that acquires predetermined parameters from the image information analyzed by the analysis unit to detect the transport state of the recording material.
An image forming system according to the present invention includes an image forming apparatus that forms an image on a recording material, and an inspection device that detects the conveyance state of the recording material conveyed to the image forming apparatus.

The present invention provides an inspection device and an image forming system that can detect the transport state of overlapping recording materials.

FIG. 1 is a diagram illustrating a schematic configuration of an image forming system. FIG. 2 is a block diagram showing a configuration of each device included in the image forming system. FIG. 4 is a block diagram of a functional configuration of a control unit of the first inspection apparatus. 5 is a flowchart of a recording material inspection method executed by the first inspection device. 11 is a diagram showing the positional relationship between the recording materials that are fed in multiples and the edge of the recording materials. FIG. 11 is a diagram showing the positional relationship between the recording materials that are fed in multiples and the edge of the recording materials. FIG. 5 is a flowchart of a recording material inspection method executed by the first inspection device. 6A to 6C are diagrams illustrating examples of patterns on a recording material that are acquired by a detection unit as predetermined parameters. 6A to 6C are diagrams illustrating examples of patterns on a recording material that are acquired by a detection unit as predetermined parameters. 6A to 6C are diagrams illustrating examples of patterns on a recording material that are acquired by a detection unit as predetermined parameters.

Hereinafter, examples of embodiments of the present invention will be described, but the present invention is not limited to the following examples.
The explanation will be given in the following order.
1. Image forming system 2. Inspection device

1. Image forming system
A specific embodiment of the image forming system of the present invention will be described below. Fig. 1 shows a schematic configuration diagram of the image forming system of this embodiment. Fig. 2 shows a block diagram of each device that constitutes the image forming system. Note that the configuration of the image forming system shown in Figs. 1 and 2 is one example, and more devices may be connected.

The image forming system shown in Figures 1 and 2 includes a paper feeder 300, a first inspection device 200, an image forming device 100, a second inspection device 400, and a post-processing device 500, which are arranged along the conveying direction of the recording material.

1 and 2, the paper feeder 300 is connected to the image forming apparatus 100 on the upstream side in the recording material conveying direction. The paper feeder 300 includes a control unit 301 that controls each unit in the paper feeder 300, a communication unit 302 for communicating with other connected devices, a paper feed unit 303 consisting of a multi-stage paper feed tray that stores recording materials, and a conveying unit 304 that conveys the recording materials. The paper feeder 300 has the paper feed unit 303 inside the housing. The paper feed unit 303 stores recording materials of the same size or different sizes. The conveying unit 304 of the paper feeder 300 includes an air blower, an adsorption conveying unit, a conveying roller, a conveying path, and the like (not shown). When a print job is started, the recording material specified in the print job is taken out of the paper feed unit 303 by the air blower, the adsorption conveying unit, and the like, and conveyed to the downstream image forming apparatus 100 via the conveying unit 304.

The first inspection device 200 is disposed between the paper feed device 300 and the image forming device 100. The first inspection device 200 inspects the recording material conveyed from the paper feed device 300. The first inspection device 200 includes a control unit 201 that controls each unit in the first inspection device 200, a communication unit 202 that communicates with other devices, a reading unit 203 that generates read image data of the conveyed recording material, a recording material detection unit 204 that detects the passage of the recording material, an image data storage unit 205 that stores the read image data generated by the reading unit 203, and a paper discharge tray 206 that discharges the recording materials that are being fed in multiples. The configuration of the first inspection device 200 will be described in detail later.

The image forming apparatus 100 includes a control unit 101 that controls each unit in the image forming apparatus 100, and a communication unit 102 for communicating with other connected devices. It also includes a transport unit 107 that transports the recording material, an image processing unit 140 that performs various image processing, an image forming unit 150 that forms a toner image on the recording material, and a fixing unit 160 that fixes the toner image formed on the recording material. The image forming apparatus 100 also includes an operation display unit 103 that allows the user to input operations and displays information, a storage unit 104 that stores various data such as image data and various settings when forming an image, and an original reading unit 110 that reads an original. The operation display unit 103 includes an input device and a display device.

The image forming unit 150 forms a toner image based on image data processed by the image processing unit 140 in accordance with an image formation command from the control unit 101. The image forming apparatus shown in FIG. 2 includes an image forming unit 150 of a so-called electrophotographic type that develops an electrostatic latent image on a charged image carrier to create a toner image of each color, and superimposes the toner images on an intermediate transfer body and transfers them to a recording material. In the image forming apparatus 100, the configuration of the image forming unit 150 is not limited to the electrophotographic type described above, and may be other image forming methods such as inkjet printing.

The second inspection device 400 includes a control unit 401 that controls each unit within the second inspection device 400, a communication unit 402 that communicates with other devices, an image reading unit 410 that reads an image of the recording material being transported, and an image data storage unit 430 that temporarily stores reference image data and read image data. The second inspection device 400 reads an image formed on the recording material in the image forming device 100 and inspects the read image.

The image reading unit 410 includes an image sensor such as an image sensor and a colorimeter such as a spectrophotometer. For example, the image reading unit 410 projects light onto the surface of the recording material and reads the reflected light from the recording material as image data. In this way, the image reading unit 410 reads the image data of the recording material S to obtain read image data. The obtained read image data is then stored in the image data storage unit 430. Furthermore, the control unit 401 performs an image inspection on the read image data to detect abnormal images.

The post-processing device 500 includes a control unit 501 that controls each unit within the post-processing device 500, a communication unit 502 that communicates with other devices, a post-processing unit 530 that performs various post-processing such as cutting, punching, and stapling on the recording material, and a paper discharge unit 590 that discharges the recording material. The processing content of the post-processing unit 330 is not particularly limited, and for example, various post-processing such as cutting, stapling, punching, and folding of the recording material is performed for each sheet of recording material or for multiple sheets. In addition, the paper discharge unit 590 is configured with paper discharge trays 590a, 590b, and 590c, as an example.

(Configuration of the control unit)
In the image forming system, each of the control units 101, 201, 301, 401, 501 of the sheet feeding device 300, the first inspection device 200, the image forming device 100, the second inspection device 400, and the post-processing device 500 has a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a non-volatile storage, etc. The CPU reads out and executes a control program stored in the ROM or the non-volatile storage to perform various arithmetic processing. The RAM provides a working memory space for the CPU and stores temporary data. The ROM stores various control programs and setting data executed by the CPU. Note that rewritable non-volatile storage such as an electrically erasable programmable read-only memory (EEPROM) or a flash memory may be used instead of the ROM. Each of the control units 101, 201, 301, 401, and 501, which includes a CPU, a RAM, a ROM, and a non-volatile storage, controls each device constituting the image forming system in accordance with various control programs.

2. Inspection Equipment
Next, a configuration of the first inspection device 200 in the above-mentioned image forming system will be described. As described above, the first inspection device 200 includes the control unit 201, the communication unit 202, the reading unit 203, the recording material detection unit 204, the image data storage unit 205, and the paper discharge tray 206.

The reading unit 203 is composed of an image sensor such as a CCD sensor or a CMOS sensor. The reading unit 203 can read the conveyed recording material over the entire direction (main scanning direction) perpendicular to the conveying direction (sub-scanning direction). The reading unit 203 generates read image data of the recording material by capturing an image of the recording material passing through. The reading unit 203 also includes an image sensor that reads the top surface (image forming surface, one surface) of the conveyed recording material, and an image sensor that reads the bottom surface (the other surface) of the recording material. The reading unit 203 generates read image data for both sides of the recording material by reading both sides of the recording material. The read image data of the recording material acquired by the reading unit 203 is stored in the image data storage unit 205.

The recording material detection unit 204 is composed of media sensors such as an ultrasonic sensor and a contact displacement sensor. The recording material detection unit 204 acquires information such as the passage of recording material through the detection area and the thickness of the passing recording material.

The control unit 201 detects double feeding of recording materials based on information from the recording material detection unit 204 and the reading unit 203. The control unit 201 also detects the state of the double-fed recording materials from the read image data of the recording materials acquired by the reading unit 203. When double feeding of recording materials is detected, the control unit 201 switches the conveying path of the recording materials from the image forming device 100 side to the paper output tray 206 side, and outputs the double-fed recording materials from the paper output tray 206.

The first inspection device 200 can detect double feeding of recording materials and the state of the double-fed recording materials by having the control unit 201 analyze the read image data acquired by the reading unit 203. The first inspection device 200 can also detect double feeding of recording materials based on the thickness of the recording materials detected by the recording material detection unit 204, and can detect the state of the double-fed recording materials by having the control unit 201 analyze the read image data acquired by the reading unit 203.

The first inspection device 200 does not have to include the recording material detection unit 204. If the first inspection device 200 does not have the recording material detection unit 204, the reading unit 203 alone detects the double feed of recording materials and detects the state of the double-fed recording materials. It is preferable that the first inspection device 200 detects the double feed of recording materials in advance using the recording material detection unit 204, and then the reading unit 203 generates read image data only for the double-fed recording materials.

[Control unit]
Next, detection of double feeding of recording materials and detection of the state of double-fed recording materials in the control unit 201 will be described. Fig. 3 shows a block diagram of the functional configuration of the control unit 201 of the first inspection device 200. As shown in Fig. 3, the control unit 201 of the first inspection device 200 has an image acquisition unit 210, an image analysis unit 220, a detection unit 230, a storage unit 240, a transport control unit 250, and a display control unit 260.

The image acquisition unit 210 acquires the read image data of the recording material that is generated by the reading unit 203 of the first inspection device 200 and stored in the image data storage unit 205 .
The image analysis unit 220 analyzes the read image data acquired by the image acquisition unit 210, and acquires image information of the recording material, such as the conveying state of the recording material, information about the recording material, the position of the ends of the recording material, and the dimensions of the recording material (length in the main scanning direction and sub-scanning direction).
In addition, when the recording material is special paper on which a pattern is formed by embossing or graining, or when the recording material is patterned paper with a design or background pattern, the image analysis unit 220 analyzes the read image data to detect the patterns on both sides of the recording material and the characteristic points of the patterns.

The detection unit 230 acquires predetermined parameters from the image information of the recording material acquired by the image analysis unit 220. Then, the detection unit 230 detects the conveying state of the recording material by comparing it with the reference parameters of the recording material stored in the storage unit 240. For example, the detection unit 230 detects, as the conveying state of the recording material, conveying abnormalities such as the occurrence of double feeding of the recording material, and conveying states such as a state of double feeding of the recording material.

The detection unit 230 also obtains the dimensions of the recording material being conveyed from the image information acquired by the image analysis unit 220 as the predetermined parameters, and obtains the dimensions of the recording material that are set in advance as the reference parameters. The dimensions of the recording material to be acquired are preferably at least one of the length of the recording material in the main scanning direction and the length of the recording material in the sub-scanning direction. The detection unit 230 then obtains the dimensions of the recording material (the length in the main scanning direction and the length in the sub-scanning direction) as the reference parameters stored in the storage unit 240, and detects double feeding of the recording material by comparing the dimensions with the above-mentioned predetermined parameters. For example, if the predetermined parameters and the reference parameters match, the detection unit 230 determines that the conveyance of the recording material is normal. If the predetermined parameters and the reference parameters differ, the detection unit 230 detects double feeding of the recording material.

In addition, when the recording material is special paper or patterned paper, the detection unit 230 detects the pattern on both sides of the recording material as a predetermined parameter from the image information acquired by the image analysis unit 220. For example, the patterns on the front side (image forming surface) and back side (opposite side of the image forming surface) of the recording material are symmetrical. Therefore, when the recording material is transported normally, the patterns on the front side and back side of the recording material are symmetrical. On the other hand, when a double feed of recording material occurs, the patterns on the front side and back side do not match in the area where the preceding recording material and the following recording material overlap. Therefore, the detection unit 230 can detect a double feed of recording material by detecting the patterns on both sides of the recording material as a predetermined parameter.

The detection unit 230 detects the pattern on the recording material by, for example, detecting multiple feature points of the pattern. A feature point is a point (position) that is easy to detect in an image, and the detection unit 230 detects, for example, the ends of the pattern, intersections between patterns, corners, points where the pattern intensity is maximum or minimum, the end points of a curve, points on a curve where the curvature is maximum, etc. as feature points of the pattern.

When the conveyance of the recording material is normal, all feature points are detected at positions that are symmetrical on both sides of the recording material. On the other hand, when double feeding of recording material occurs, some feature points are detected at positions that are not symmetrical on both sides in the area where the preceding recording material overlaps with the succeeding recording material. For this reason, the detection unit 230 can detect double feeding of recording material by detecting the positions of feature points on both sides of the recording material as a predetermined parameter.

Furthermore, when the above-mentioned double feeding is detected, the detection unit 230 detects, from the image information of the recording materials acquired by the image analysis unit 220, whether the preceding recording material or the following recording material is located on the imaging surface side among the recording materials overlapping in the transport direction.

For example, the entire length of the overlapping recording material in the sub-scanning direction and the position of the end of the overlapping recording material are detected. When the overlapping recording materials are misaligned, the end of either the rear end of the preceding recording material or the front end of the following recording material is detected at the boundary portion where the overlapping recording materials overlap between the front end of the preceding recording material and the rear end of the following recording material. Therefore, if the distance from the front end of the preceding recording material to the end of the boundary portion is the length in the sub-scanning direction of the recording material registered as the reference parameter, the detection unit 230 can determine that the preceding recording material is located on the imaging surface side. Also, if the distance to the end of the boundary portion is less than the length in the sub-scanning direction of the recording material registered as the reference parameter, the detection unit 230 can determine that the following recording material is located on the imaging surface side.

In addition, when the recording material is special paper or patterned paper, the detection unit 230 can detect the position of the characteristic points to detect which of the recording materials overlapping in the transport direction, the leading recording material or the trailing recording material, is located on the imaging surface side. As described above, the patterns on both sides of the recording material are symmetrical. Therefore, when overlapping recording materials occurs, the positions of the pattern (characteristic points) of the leading recording material and the pattern (characteristic points) of the trailing recording material are detected at positions shifted in the transport direction on the back and front sides. Therefore, by detecting the shift of the patterns (characteristic points) in the overlapping area between the leading recording material and the trailing recording material, it is possible to detect which of the leading recording material or the trailing recording material is located on the imaging surface side.

The memory unit 240 stores parameters (reference parameters) that serve as a reference when detecting the transport state. It also stores various information acquired by the image analysis unit 220 and various information detected by the detection unit in a storage device and reads them out. The memory unit 240 may store information in a storage device (storage, etc.) that constitutes the control unit 201, or it may be the image data storage unit 205 of the first inspection device 200.

The conveyance control section 250 controls the conveyance of the recording material based on the conveyance state of the recording material detected by the detection section 230. In the case of double feeding, the recording material is discharged from the apparatus without forming an image thereon.
The display control unit 260 causes the display unit to display various types of information in the first inspection device 200. For example, the display control unit 260 displays information notifying the occurrence of double feeding of recording materials, information to eject the recording materials where double feeding has occurred, and the like, on the operation display unit 103 of the image forming apparatus 100. Note that the display control unit 260 may not only be included in the control unit 201 of the first inspection device 200, but may also be included in a control unit of another device in the image forming system, for example, the control unit 101 of the image forming apparatus 100.

[Testing method]
Next, there will be described a method for inspecting the conveyance state of the recording material in the first inspection device 200. The first inspection device 200 detects the occurrence of double feeding and the state of the double-fed recording material as the conveyance state of the recording material.

(Flow chart of inspection method-1)
FIG. 4 shows a flowchart of the recording material inspection method executed by the first inspection apparatus 200. As shown in FIG.
First, in the image forming system, a recording material is fed from the sheet feeding device 300 to the first inspection device 200 (step S101). The control unit 301 of the sheet feeding device 300 drives the sheet feeding unit 303 and the conveying unit 304. Then, the recording material accommodated in the sheet feeding unit 303 is conveyed via the conveying unit 304 to the first inspection device 200 disposed downstream of the sheet feeding device 300.

Next, the recording material conveyed from the paper feeder 300 to the first inspection device 200 is detected by the recording material detection unit 204 of the first inspection device 200, and is further read by the reading unit 203 to generate read image data, which is stored in the image data storage unit 205 (step S102). The recording material detection unit 204 may detect the thickness of the recording material as the recording material arrives. If the thickness of the recording material is detected, the thickness of the recording material is also stored in the image data storage unit 205 together with the read image data.

Next, the image acquisition unit 210 acquires the scanned image data stored in the image data storage unit 205, and the image analysis unit 220 analyzes the acquired scanned image data (step S103). At this time, the image analysis unit 220 analyzes the scanned image data to acquire image information about the recording material, such as the conveyance state of the recording material, information about the recording material, the position of the edges of the recording material, and the dimensions of the recording material (length in the main scanning direction and sub-scanning direction).

Next, the detection unit 230 extracts predetermined parameters from the image information of the read image data analyzed by the image analysis unit 220 (step S104). Examples of the predetermined parameters extracted by the detection unit 230 include the length of the recording material in the main scanning direction and the length in the sub-scanning direction.

Next, the detection unit 230 reads out the reference parameters of the recording material stored in the storage unit 240, and determines whether the extracted predetermined parameters of the recording material match the reference parameters (step S105). For example, the detection unit 230 extracts the length in the sub-scanning direction from the image information of the read image data as the predetermined parameter. The detection unit 230 then reads out the length in the sub-scanning direction of the recording material that is set in advance from the storage unit 240 as the reference parameter. The detection unit 230 then compares the length in the sub-scanning direction of the recording material extracted as the predetermined parameter with the length in the sub-scanning direction of the recording material read out as the reference parameter. In this way, the detection unit 230 determines whether the predetermined parameters match the reference parameters.

When the predetermined parameter and the reference parameter match (YES in step S105), the detection unit 230 determines that the conveyance of the recording material is normal (step S106).
Then, the conveyance control section 250 conveys the recording material without switching the conveyance path, and conveys the recording material from the first inspection device 200 to the image forming device 100 (step S107).

If the predetermined parameters are different from the reference parameters (NO in step S105), the detection unit 230 detects a recording material transport abnormality (step S108). For example, the detection unit 230 detects the occurrence of double feeding of recording materials as a recording material transport abnormality.

Next, the detection unit 230 detects the positions of the ends of the overlapping recording materials as a predetermined parameter of the recording materials for which abnormal conveyance was detected (step S109). The detection unit 230 detects the leading end of the preceding recording material and the trailing end of the following recording material for the overlapping recording materials from the image information analyzed by the image analysis unit 220. Furthermore, the detection unit 230 detects the ends of the recording materials in the area where the recording materials overlap. The ends of the recording materials in the area where the recording materials overlap are either the trailing end of the preceding recording material or the leading end of the following recording material.

Next, the detection section 230 determines whether or not an edge of the area where the recording materials overlap has been detected on the rear side in the transport direction of the overlapped recording materials (step S110).
5 and 6 show the positional relationship between the overlapped recording materials and the ends of the recording materials. Fig. 5 and Fig. 6 show the state in which overlapped recording materials 700 are transported in the direction of the arrow. The overlapped recording materials 700 are transported in a state in which the preceding recording material 701 and the succeeding recording material 702 are partially overlapped.
In the case of the overlapped printing material 700 shown in Fig. 5, the detection unit 230 detects the leading end 701a and the trailing end 701b of the preceding printing material 701, and the trailing end 702b of the following printing material 702. On the other hand, in the case of the overlapped printing material 700 shown in Fig. 6, the detection unit 230 detects the leading end 701a of the preceding printing material 701, and the leading end 702a and the trailing end 702b of the following printing material 702.

As shown in FIG. 5, when the trailing end 701b of the preceding recording material 701 is detected, the end (trailing end 701b) in the area where the recording materials overlap is detected on the rear side (rear half) in the transport direction. Also, as shown in FIG. 6, when the leading end 702a of the succeeding recording material 702 is detected, the end (leading end 702a) in the area where the recording materials overlap is detected on the rear side (rear half) in the transport direction. Therefore, the detection unit 230 can detect the state of the overlapping recording materials 700 based on the position of the end detected in the area where the recording materials overlap.

If the edge of the overlapping area of the recording materials is detected on the rear side of the transport direction of the overlapping recording materials (YES in step S110), the detection unit 230 detects the state of the overlapping recording materials as being in a state where the preceding recording material is positioned on the upper side (image forming surface) (step S111).

If the edge of the overlapping area of the recording materials is not detected on the rear side of the conveying direction of the overlapped recording materials (NO in step S110), the detection unit 230 detects the state of the overlapped recording materials as being in a state where the succeeding recording material is positioned on the upper side (image forming surface) (step S112).

Next, the state of the overlapped recording materials detected by the detection unit 230 is recorded in the storage unit 240 (step S113).
Next, the display control unit 260 displays information such as the occurrence of double feeding of recording materials and ejection of recording materials on the operation display unit 103 of the image forming system (step S114), thereby notifying the user of the occurrence of double feeding and the state of the double-fed recording materials.
Next, the conveyance control unit 250 switches the conveyance path, and ejects the recording material in which the double feed occurred from the paper ejection tray 206 (step S115).
After the recording material is transported to the image forming apparatus 100, or after the recording materials are discharged by double feeding, the process according to this flowchart ends.

(Inspection method flow chart-2)
Next, another embodiment of the recording material inspection method will be described. Fig. 7 shows a flowchart of the recording material inspection method executed by the first inspection device. Note that the inspection method of this embodiment is an inspection method for when the recording material is special paper or patterned paper, and performs the same processing as the above inspection method with some exceptions. Therefore, detailed explanations of the same processing as the above inspection method will be omitted.

First, in the image forming system, a recording material is fed from the sheet feeding device 300 to the first inspection device 200 (step S201). Next, the recording material conveyed from the sheet feeding device 300 to the first inspection device 200 is detected by the recording material detection unit 204 of the first inspection device 200, and is further read by the reading unit 203 to generate read image data, which is stored in the image data storage unit 205 (step S202).
Next, the image acquisition unit 210 acquires the scanned image data stored in the image data storage unit 205, and the image analysis unit 220 analyzes the acquired scanned image data (step S203). At this time, the image analysis unit 220 analyzes the scanned image data to acquire image information of the recording material, such as patterns formed by unevenness such as embossing or graining on the surface of the recording material, various patterns such as patterns and background patterns, and feature points formed by these patterns, for both sides of the recording material.

Next, the detection unit 230 extracts predetermined parameters from the image information of the read image data analyzed by the image analysis unit 220 (step S204). The predetermined parameters extracted by the detection unit 230 include, for example, the pattern of the recording material and characteristic points of the pattern. The detection unit 230 also extracts the above-mentioned predetermined parameters for both sides of the recording material.

Next, the detection unit 230 compares the pattern and pattern feature points of the recording material extracted as the predetermined parameters between both sides of the recording material, and determines whether the predetermined parameters match between both sides (step S205). For example, the detection unit 230 obtains the pattern of the front side of the recording material from the image information of the read image data as the predetermined parameter. Furthermore, the detection unit 230 obtains the pattern of the back side of the recording material from the image information of the read image data as the predetermined parameter. The detection unit 230 then compares the pattern of the front side of the recording material with the pattern of the back side.

If the specified parameters of the front side and the back side of the recording material match (YES in step S205), the detection unit 230 determines that the recording material is being transported normally (step S206). Then, the transport control unit 250 transports the recording material without switching the transport path, and transports the recording material from the first inspection device 200 to the image forming device 100 (step S207).

If the predetermined parameters of the front side and the back side of the recording material do not match (NO in step S205), the detection unit 230 detects a recording material transport abnormality (step S208). For example, the detection unit 230 detects the occurrence of double feeding of recording material as a recording material transport abnormality.

Examples of patterns on recording materials that the detection unit 230 acquires as the specified parameters are shown in Figures 8, 9, and 10. Figure 8 shows a case where the specified parameters on the front side match the specified parameters on the back side. Also, Figure 9 shows a case where the specified parameters on the front side do not match the specified parameters on the back side. Furthermore, Figure 10 shows a state where recording materials are fed in a state where they are partially misaligned.

The detection unit 230 extracts the pattern on a front surface 601 of the printing material as a predetermined parameter for the front surface side, and obtains the pattern on a back surface 602 as a predetermined parameter for the back surface side, as shown in FIG.
When no double feeding or the like has occurred on the recording material, the pattern on the front surface 601 and the pattern on the back surface 602 extracted by the detection unit 230 as the predetermined parameters are mirror-symmetrical in the main scanning direction or the sub-scanning direction. In this way, when the patterns on the front surface and the back surface are symmetrical, the detection unit 230 can determine that the predetermined parameters on the front surface and the predetermined parameters on the back surface match. Note that the pattern on the front surface 601 and the pattern on the back surface 602 may be symmetrical other than mirror-symmetrical, or may match as they are, depending on the imaging method and the processing of the read image data.

In addition, the detection unit 230 may extract the pattern on the front surface 603 of the recording material as the predetermined parameters of the front surface side, and obtain the pattern on the back surface 604 as the predetermined parameters of the back surface side, as shown in FIG. 9. In FIG. 9, the patterns on the front surface 603 and the back surface 604 extracted by the detection unit 230 as the predetermined parameters are not symmetrical in the main scanning direction or the sub-scanning direction. In this way, when the overall patterns on the front surface and the back surface are not symmetrical, the detection unit 230 can determine that the predetermined parameters of the front surface and the predetermined parameters of the back surface do not match. Furthermore, in this case, the detection unit 230 can determine that a double feed has occurred, in which the recording materials are transported overlapping each other without being misaligned.

FIG. 10 shows a state in which a printing material 611 and a printing material 612 are conveyed overlapping each other as a double-fed printing material 610 .
The patterns on the front surface 605 and the back surface 606 of the overlapped recording material 610 extracted by the detection unit 230 as the predetermined parameters have some mirror-symmetrical patterns, but are not mirror-symmetrical as a whole. For example, the area where the recording material 611 is detected from the front surface 605 is partially mirror-symmetrical with the area 611a on the back surface 606. Also, the area where the recording material 612 is detected from the back surface 606 is partially mirror-symmetrical with the area 612a on the back surface 606. In this way, when the patterns of the entire recording material detected in the read image data are not symmetrical or matched, and have areas that are partially mirror-symmetrical or matched, the detection unit 230 can determine that the predetermined parameters of the front surface and the predetermined parameters of the back surface do not match. Furthermore, in this case, the detection unit 230 can determine that the overlapping of the recording materials is caused by the recording materials being conveyed while overlapping with some misalignment.

Next, the detection unit 230 determines whether some of the predetermined parameters of the recording material in which abnormal conveyance was detected match between the front and back sides of the overlapping recording material (step S209). From the image information analyzed by the image analysis unit 220, the detection unit 230 determines whether the overlapping recording material 610 has an area where the pattern on the front side 605 and the pattern on the back side 606 are partially mirror-symmetric or match, as shown in FIG. 10 above, or whether the overall pattern on the front side and the back side is not symmetric, as shown in FIG. 9 above.

If some of the specified parameters match between the front and back sides of the overlapping recording materials (YES in step S209), the detection unit 230 detects that the overlapping recording materials are being transported in a misaligned state (step S210).

Next, the detection unit 230 extracts the position of the end of the overlapping recording material as a predetermined parameter of the recording material for which abnormal conveyance was detected (step S211). The detection unit 230 then determines whether the end of the area where the recording materials overlap has been detected on the rear side of the conveyance direction of the overlapping recording material (step S212).

If the edge of the overlapping area of the recording materials is detected on the rear side of the conveying direction of the overlapping recording materials (YES in step S212), the detection unit 230 detects the state of the overlapping recording materials as being in a state where the preceding recording material is positioned on the upper side (image forming surface) (step S213).

If the edge of the overlapping area of the recording materials is not detected on the rear side of the conveying direction of the overlapped recording materials (NO in step S212), the detection unit 230 detects the state of the overlapped recording materials as being in a state where the succeeding recording material is positioned on the upper side (image forming surface) (step S214).

If some of the specified parameters do not match between the front and back sides of the overlapping recording materials (NO in step S209), the detection unit 230 detects that the overlapping recording materials are being transported in an overlapping state without being misaligned (step S215).

Next, the state of the overlapped recording materials detected by the detection unit 230 is recorded in the storage unit 240 (step S216).
Next, the display control unit 260 displays information such as the occurrence of double feeding of recording materials and ejection of recording materials on the operation display unit 103 of the image forming system (step S217), thereby notifying the user of the occurrence of double feeding and the state of the double-fed recording materials.
Next, the conveyance control unit 250 switches the conveyance path, and ejects the recording material in which the double feed occurred from the paper ejection tray 206 (step S218).
After the recording material is transported to the image forming apparatus 100, or after the recording materials are discharged by double-feeding, the process according to this flowchart is completed.

The present invention is not limited to the configurations described in the above-mentioned embodiment examples, and various modifications and variations are possible without departing from the scope of the present invention.

100 Image forming apparatus, 101, 201, 301, 401, 501 Control unit, 102, 202, 302, 402 Communication unit, 103 Operation display unit, 104, 240 Storage unit, 107, 304 Conveying unit, 110 Document reading unit, 140 Image processing unit, 150 Image forming unit, 160 Fixing unit, 200 First inspection device, 203 Reading unit, 204 Recording material detection unit, 205, 430 Image data storage unit, 206, 590a, 590b, 590c Paper discharge tray, 210 Image acquisition unit, 220 Image analysis unit, 230 Detection unit, 250 Conveying control unit, 260 Display control unit, 300 Paper feeder, 303 Paper feed unit, 330, 530 Post-processing unit, 400 Second inspection device, 410 Image reading unit, 500 Post-processing device, 502 Communication unit, 590 Paper discharge unit, 601, 603, 605, 602 Front surface, 604, 606 Back surface, 610, 611, 612, 700, 701, 702 Recording material, 611a, 612a Area, 701a, 702a Front end, 701b, 702b Rear end

Claims (8)

a reading section that reads a recording material being conveyed on a conveying path and generates read image data of the recording material;
a control unit that detects a conveying state of the recording material based on the read image data,
The control unit is
an image acquisition unit that acquires the read image data read by the reading unit;
an analysis unit that analyzes the read image data acquired by the image acquisition unit and acquires image information of the recording material;
a detection unit that acquires a predetermined parameter from the image information analyzed by the analysis unit and detects a conveyance state of the recording material based on the predetermined parameter ,
the analyzing unit acquires, as the image information, a first pattern formed on one side of the recording material being conveyed and a second pattern formed on the other side of the recording material;
The detection unit detects a conveying state of the recording material by acquiring characteristics of the first pattern and the second pattern as the predetermined parameters and comparing the characteristics of the first pattern and the second pattern. the control unit has a storage unit that stores a reference parameter that is a reference for detecting an abnormality in the transport state,
The inspection device according to claim 1 , wherein the detection unit detects an abnormality in the transport state by comparing the predetermined parameter acquired from the image information with a reference parameter. The inspection device according to claim 2 , wherein the detection section acquires a dimension of the recording material detected from the image information as the predetermined parameter, and acquires a dimension of the recording material that is set in advance as the reference parameter. The inspection device according to claim 3 , wherein the detection unit acquires a length of the recording material in a conveying direction as the dimension of the recording material. The inspection device according to claim 3 or 4, wherein the detection section acquires a length of the recording material in a direction perpendicular to a conveying direction of the recording material as the dimension of the recording material. The detection unit detects double feeding of the recording material as the abnormality in the conveying state.
6. An inspection device according to claim 1 . When the detection unit detects double feeding of the recording materials,
When the detection unit detects an edge of the recording material in a portion where the recording materials overlap, it determines that the recording materials are being fed in a misaligned state.
7. The inspection apparatus according to claim 6 . An image forming system including an image forming apparatus that forms an image on a recording material, and an inspection apparatus that detects a conveyance state of the recording material conveyed to the image forming apparatus,
The inspection device includes:
a reading section that reads a recording material being conveyed on a conveying path and generates read image data of the recording material;
a control unit that detects a conveying state of the recording material based on the read image data,
The control unit is
an image acquisition unit that acquires the read image data read by the reading unit;
an analysis unit that analyzes the read image data acquired by the image acquisition unit and acquires image information of the recording material;
a detection unit that acquires a predetermined parameter from the image information analyzed by the analysis unit and detects a conveyance state of the recording material based on the predetermined parameter ,
the analyzing unit acquires, as the image information, a first pattern formed on one side of the recording material being conveyed and a second pattern formed on the other side of the recording material;
The detection unit detects a conveying state of the recording material by acquiring characteristics of the first pattern and the second pattern as the predetermined parameters and comparing the characteristics of the first pattern and the second pattern.

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