JP2022065551A - Inspection device, image forming system, inspection method, and program - Google Patents

Abstract

To improve the accuracy of detecting a poor condition of a recording medium.SOLUTION: An inspection device comprises: a difference image generation unit that generates difference image data indicating the difference between read image data obtained by reading a recording medium on which an image is formed and master image data to be a reference of comparison; an image processing unit that converts the difference image data into image data in which part of an image is emphasized; and an output unit that, based on the converted difference image data, outputs information indicating the presence or absence of a poor condition of the recording medium.SELECTED DRAWING: Figure 5

Description

The present invention relates to an inspection device, an image forming system, an inspection method and a program.

Conventionally, in commercial printing and the like, a technique for inspecting whether printing by a printer is normally performed from a result of reading an image printed by a printer has been developed. For example, a wrinkle detecting device for detecting a printing abnormality caused by "wrinkles" generated on printed paper or the like is disclosed. This wrinkle detection device detects "wrinkles" generated on the recording medium by comparing the scanned image data obtained by reading the image formed on the recording medium with the image data used for forming the image on the recording medium. do.

Of the differences in pixel values that occur between the scanned image data and the reference image data, the difference due to poor condition of the recording medium such as "wrinkles" is greater than the difference due to defects in the image forming apparatus. Often small. Therefore, it is difficult to extract the difference in pixel values due to the poor condition of the recording medium by simply comparing the image data as in the conventional technique, and the detection accuracy is not sufficient.

The disclosed technique aims to improve the detection accuracy of the state defect of the recording medium.

The disclosed technique includes a difference image generation unit that generates a difference image data showing a difference between a scanned image data obtained by reading a recording medium on which an image is formed and a master image data as a reference for comparison, and the difference image data. An image processing unit that converts a part of the image into image data emphasized, and an output unit that outputs information indicating the presence or absence of a state defect of the recording medium based on the converted difference image data. It is an inspection device to be equipped.

It is possible to improve the detection accuracy of the state defect of the recording medium.

It is a figure which shows an example of the system structure of the image formation system which concerns on 1st Embodiment. It is a figure which shows an example of the hardware composition of the image forming apparatus. It is a figure which shows an example of the structure of the electric system of an image forming apparatus. It is a figure which shows an example of the hardware composition of the inspection apparatus. It is a figure which shows an example of the function of the image forming apparatus and inspection apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the flow of the inspection process which concerns on 1st Embodiment. It is a figure which shows an example of the flow of the alignment processing. It is a figure for demonstrating the alignment method. It is a figure for demonstrating the method of generating a difference image. It is a figure which shows an example of the flow of image processing. It is the first figure for demonstrating the method of image processing. It is a 2nd figure for demonstrating the method of image processing. It is a figure which shows an example of the result of image processing. It is a figure which shows an example of the flow of a wrinkle determination process. It is a figure which shows an example of the result of a wrinkle determination process. It is a figure which shows an example of the system structure of the image formation system which concerns on the 2nd Embodiment. It is a figure which shows an example of the function of the image forming apparatus and inspection apparatus which concerns on 2nd Embodiment. It is a figure which shows an example of the flow of the inspection process which concerns on the 2nd Embodiment. It is a figure which shows an example of the inspection result display screen which concerns on the 2nd Embodiment. It is a figure which shows an example of the flow of the print stop processing which concerns on the 2nd Embodiment. It is a figure which shows an example of the print stop confirmation screen which concerns on 2nd Embodiment.

(First embodiment)
Hereinafter, embodiments of the image forming system according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of a system configuration of an image forming system according to the first embodiment.

The image forming system 1 includes an image forming device 10, an inspection device 20, a DFE (Digital Front End) 30, a terminal device 40, and a job management server 50.

The image forming apparatus 10, the inspection apparatus 20, the DFE 30, the terminal apparatus 40, and the job management server 50 are connected to each other so as to be able to communicate with each other via the communication network 60.

The image forming apparatus 10 is an apparatus for forming an image, for example, a color production printer. The image forming apparatus 10 receives image data from the DFE 30 and prints an image on paper based on the received image data.

Further, the image forming apparatus 10 includes a reading device. The reading device reads the paper on which the image is printed and generates the scanned image data. Then, the image forming apparatus 10 transmits the scanned image data generated by the reading apparatus to the inspection apparatus 20.

The inspection device 20 inspects whether or not "wrinkles" are generated on the paper of the image forming apparatus 10 based on the scanned image data received from the image forming apparatus 10. Further, the inspection device 20 transmits information indicating the inspection result to the image forming device 10. The image forming apparatus 10 displays information indicating the received inspection result on the operation panel.

The paper is an example of a recording medium, and may be another sheet-like material such as a film or plastic. Further, "wrinkles" are an example of poor condition of the recording medium. The poor condition of the recording medium may be other than that, for example, it may be torn, defective, or soiled. When a poor condition occurs in the recording medium, the scanned image data read from the recording medium includes not only the image formed by printing but also the pixel values affected by the poor condition of the recording medium. ing. Therefore, the inspection device 20 inspects whether or not the state defect has occurred by extracting the pixel value affected by the state defect of the recording medium given to the scanned image data.

When the DFE 30 receives image data from the terminal device 40 together with a signal instructing printing of an image, the built-in RIP (Raster Image Processor) engine processes the received image data by the image forming apparatus 10. It is converted into image data and the RIP image data is transmitted to the image forming apparatus 10.

The terminal device 40 is a terminal that receives an operation from the user and instructs the printing of an image. Specifically, the terminal device 40 transmits the job data including the image data to the DFE 30 or the job management server 50.

When the job management server 50 receives the job data from the terminal device 40, the job management server 50 adds it as a queue to the storage unit that stores the job data waiting to be printed. Then, the job management server 50 extracts the job data from the queue in the order in which it is added to the queue or according to the priority set as appropriate, and sends the job data to the DFE 30.

Next, the hardware configuration of the apparatus included in the image forming system 1 will be described.

FIG. 2 is a diagram showing an example of the hardware configuration of the image forming apparatus.

The image forming apparatus 10 includes a printer 101, a stacker 102, and an operating device 103.

The printer 101 receives RIP image data from DFE30 and forms an image on paper based on the received RIP image data.

The printer 101 includes a configuration in which photoconductor drums 112Y, 112M, 112C, and 112K (hereinafter, collectively referred to as photoconductor drums 112) of each color are arranged along a transport belt 111 which is an endless moving means.

Specifically, the printer 101 includes photoconductor drums 112Y, 112M, 112C and 112K arranged in order from the upstream side in the transport direction of the transport belt 111. The transfer belt 111 is an intermediate transfer belt on which an intermediate transfer image for transferring from the paper feed tray 113 to paper fed along the transfer belt 111 is formed.

The printer 101 superimposes and transfers the toner images of K (black), C (cyan), M (magenta) and Y (yellow) developed by the toner on the surface of the photoconductor drum 112 of each color on the transport belt 111 and transfers the toner images. By doing so, a full-color image is formed. Then, the printer 101 transports the full-color image formed on the transport belt 111 on the path by the function of the transfer roller 114 at the position closest to the transport path of the paper shown by the broken line in the drawing. Transfer to the paper.

The printer 101 further conveys the paper on which the image is formed on the paper surface, fixes the image by the fixing roller 115, and then conveys it to the reading device 131. The reading device 131 reads the paper conveyed via the fixing roller 115 and generates scanned image data.

In the case of single-sided printing, the printer 101 discharges the paper read by the reading device 131 to the stacker 102 as it is. Further, in the case of double-sided printing, the printer 101 inverts the paper read by the reading device 131 by the inversion pass 116, and then conveys the paper to the transfer position of the transfer roller 114 again.

Subsequently, the printer 101 transfers and fixes the toner image on the opposite side of the paper printed on one side. Then, the reading device 131 reads the printed surface. The printer 101 then ejects the double-sided printed paper to the stacker 102.

The stacker 102 stacks and stores the paper ejected from the printer 101 on the tray 141.

The operation device 103 has an operation panel and the like, and receives user operations such as print setting and print execution. Specifically, the operating device 103 displays information indicating the inspection result by the inspection device 20.

Although FIG. 2 shows an example in which the image forming apparatus 10 has an electrophotographic image forming mechanism, another image forming mechanism such as an inkjet method may be provided.

FIG. 3 is a diagram showing an example of the configuration of the electrical system of the image forming apparatus.

The image forming apparatus 10 includes a controller 910, a short-range communication circuit 920, an engine control unit 930, an operation panel 940, and a network I / F 950.

Of these, the controller 910 is a CPU (Central Processing Unit) 901, a system memory (MEM-P) 902, a north bridge (NB) 903, a south bridge (SB) 904, and an ASIC (Application Specific Integrated), which are the main parts of a computer. It has a Circuit) 906, a local memory (MEM-C) 907 which is a storage unit, an HDD (Hard Disk Drive) controller 908, and an HD909 which is a storage unit.

Further, the NB 903 and the ASIC 906 are connected by an AGP (Accelerated Graphics Port) bus 921.

Of these, the CPU 901 is a control unit that controls the entire image forming apparatus 10. The NB903 is a bridge for connecting the CPU901, the MEM-P902, the SB904, and the AGP bus 921, and has a memory controller that controls reading and writing to the MEM-P902, a PCI (Peripheral Component Interconnect) master, and an AGP target. Has.

The MEM-P902 includes a ROM 902a that is a memory for storing programs and data that realizes each function of the controller 910, and a RAM 902b that is used as a memory for developing programs and data and for drawing in memory printing. The program stored in the RAM 902b is configured to be recorded and provided as a file in an installable format or an executable format on a computer-readable recording medium such as a CD-ROM, CD-R, or DVD. You may.

The SB904 is a bridge for connecting the NB903 to a PCI device and a peripheral device. The ASIC 906 is an IC (Integrated Circuit) for image processing applications having hardware elements for image processing, and has a role of a bridge connecting the AGP bus 921, the PCI bus 922, the HDD controller 908, and the MEM-C907, respectively.

The ASIC906 includes a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC906, a memory controller that controls the MEM-C907, and a plurality of DMACs (Direct Memory Access Controllers) that rotate image data by hardware logic. It also includes a PCI unit that transfers data between the scanner unit 931 and the printer unit 932 via the PCI bus 922. The ASIC906 may be connected to an interface such as a USB (Universal Serial Bus) interface or an IEEE 1394 (Institute of Electrical and Electronics Engineers 1394) interface.

The MEM-C907 is a local memory used as a copy image buffer and a code buffer. The HD909 is a storage for accumulating image data, accumulating font data used at the time of printing, accumulating forms, and the like. The HD909 controls reading or writing of data to the HD909 according to the control of the CPU 901.

The AGP bus 921 is a bus interface for a graphics accelerator card proposed for speeding up graphic processing. The AGP bus 921 can speed up the graphics accelerator card by directly accessing the MEM-P902 at high throughput.

Further, the short-range communication circuit 920 includes a short-range communication antenna 920a. The short-range communication circuit 920 is a communication circuit such as NFC and Bluetooth (registered trademark).

Further, the engine control unit 930 is composed of a scanner unit 931 and a printer unit 932. Further, the operation panel 940 displays the current setting value, the selection screen, and the like, and receives the panel display unit 940a such as a touch panel that accepts the input from the operator, and the setting value of the condition related to image formation such as the density setting condition. It includes an operation key 940b including a numeric keypad and a start key for receiving a copy start instruction.

The controller 910 controls the entire image forming apparatus 10, for example, drawing, communication, input from the operation panel 940, and the like. The scanner unit 931 or the printer unit 932 executes image processing such as error diffusion and gamma conversion.

Further, the network I / F950 is an interface for performing data communication using the communication network 60. The short-range communication circuit 920 and the network I / F 950 are electrically connected to the ASIC 906 via the PCI bus 922.

FIG. 4 is a diagram showing an example of the hardware configuration of the inspection device.

The inspection device 20 is composed of a computer and includes a CPU 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, an HDD / SSD (Solid State Drive) 204, and an I / F 205.

The CPU 201 reads the program stored in the ROM 202 or the HDD / SSD 204 and stores it in the RAM 203. Then, the CPU 201 executes various processes described later according to the program stored in the RAM 203.

ROM 202 is a non-volatile auxiliary storage device. The ROM 202 stores a program that defines the basic operation of the inspection device 20 such as the BIOS.

The RAM 203 is a volatile main storage device. The RAM 203 is used as a work area of the CPU 201.

The HDD / SSD 204 is a large-capacity non-volatile auxiliary storage device. The HDD / SSD 204 stores received read image data, programs for various processes described later, setting information, and the like.

The I / F 205 is, for example, a LAN (Local Area Network) card or the like, and is a repeater for communicating with the communication network 60.

Next, the function of the apparatus included in the image forming system 1 will be described.

FIG. 5 is a diagram showing an example of the functions of the image forming apparatus and the inspection apparatus according to the first embodiment.

The image forming apparatus 10 includes a RIP image receiving unit 11, a RIP image transmitting unit 12, an image forming unit 13, a reading unit 14, and an operation unit 15.

The RIP image receiving unit 11 receives the RIP image data 801 from the DFE 30. The RIP image data 801 is image data in CMYK format. The RIP image transmission unit 12 transmits the received RIP image data 801 to the image forming unit 13 and also transmits it to the inspection device 20. The RIP image receiving unit 11 and the RIP image transmitting unit 12 are realized by the network I / F950.

The image forming unit 13 prints an image on a recording medium based on the RIP image data 801. The image forming unit 13 is realized by the printer 101.

The reading unit 14 reads the recording medium (printed matter 802) on which the image is printed, generates the scanned image data 803, and transmits the generated scanned image data 803 to the inspection device 20. The reading unit 14 is realized by the reading device 131.

The operation unit 15 receives the inspection result information 808 from the inspection device 20 and displays the received inspection result information 808. The inspection result information 808 includes a determination result of whether or not wrinkles are present on the paper, the shape and size of the wrinkles when they are present, and the like. The operation unit 15 is realized by the operation device 103.

The inspection device 20 includes a master image generation unit 21, a reading image acquisition unit 22, an alignment processing unit 23, a difference image generation unit 24, an image processing unit 25, a wrinkle determination unit 26, and an output unit 27. To prepare for.

The master image generation unit 21 generates master image data 804 based on the RIP image data 801 received from the image forming apparatus 10. Specifically, the master image generation unit 21 converts the CMYK format RIP image data 801 into the RGB format master image data 804. The master image generation unit 21 is realized by the CPU 201 or the like.

The master image data 804 is data that serves as a reference for comparison with the scanned image data 803, and functions as correct answer data when correctly printed. Further, the master image data 804 includes data indicating feature points (hereinafter referred to as reference points) that serve as reference points for comparison during the alignment process. The master image generation unit 21 determines the number of reference points for each page according to the paper size, image pattern, and the like, and embeds data indicating the determined number of reference points in the master image data 804.

The scanned image acquisition unit 22 receives the scanned image data 803 from the image forming apparatus 10. The scanned image acquisition unit 22 is realized by the I / F 205.

The alignment processing unit 23 aligns the master image data 804 and the read image data 803 in order to compare them. Specifically, the position of the image to be printed differs depending on the situation such as transportation and printing. Therefore, the alignment processing unit 23 searches the scanned image data 803 for points corresponding to the reference points included in the master image data 804, and evaluates them as the same pixels included in the master image data 804 and the scanned image data 803. Calculate the magnitude of the relative positional deviation of the pixels to be used.

Then, the alignment processing unit 23 generates the positional deviation information 805 indicating the magnitude of the positional deviation. For example, the misalignment information 805 includes the difference between the X coordinate value and the Y coordinate value between the master image data 804 and the read image data 803.

The difference image generation unit 24 generates the difference image data 806. Specifically, the difference image generation unit 24 calculates the difference between the pixel values of the master image data 804 and the read image data 803 for each pixel based on the position shift information 805. Here, the difference image generation unit 24 calculates the difference in pixel values for each of the red (Red), green (Green), and blue (Blue) colors in order to compare the RGB format data, and calculates each color. The difference image data 806 showing the difference is generated.

The image processing unit 25 performs filtering processing on the difference image data 806 to generate edge-enhanced image data 807 in which the edges included in the difference image data 806 are emphasized.

The edge is a term of image processing indicating a boundary in which the brightness (pixel value) changes discontinuously. When the edge extends linearly, it can be said that the edge forms a boundary line.

Further, the emphasis refers to a process of converting the difference of the pixel values having a certain tendency among the differences of the pixel values in the difference image data 806 into a value larger than the original value by a filtering process or the like. Alternatively, in order to make a pixel value having a certain tendency stand out as a large value, a process may be performed in which a value deviating from the tendency is converted into a small value.

This facilitates the determination of the presence or absence of wrinkles by the wrinkle determination unit 26 even when the difference in pixel values due to wrinkles is small. That is, even if the effect of poor condition on the recording medium such as wrinkles on the color is small and the difference between the pixel values included in the difference image data 806 is small, the edge is emphasized to emphasize the recording medium. It is possible to emphasize the entire area where the poor condition of is generated. As a result, it is possible to easily determine the entire region where the recording medium is in poor condition as the recording medium in poor condition.

The wrinkle determination unit 26 determines whether or not the paper has wrinkles based on the edge-enhanced image data 807 generated by the image processing unit 25.

The output unit 27 transmits the inspection result information 808 indicating the inspection result based on the determination result of the wrinkle determination unit 26 to the image forming apparatus 10.

Next, the operation of the image forming system 1 will be described.

FIG. 6 is a diagram showing an example of a flow of inspection processing according to the first embodiment.

The inspection device 20 executes an inspection process every time the image forming device 10 prints one page on paper. When the inspection device 20 starts the inspection process, the master image generation unit 21 generates the master image data 804 (step S11).

Next, the scanned image acquisition unit 22 acquires the scanned image data 803 (step S12). The order of the processes in steps S11 and S12 may be reversed, and the inspection device 20 may execute these processes in parallel.

Next, the alignment processing unit 23 executes the alignment process (step S13). The details of the alignment process will be described later.

Next, the difference image generation unit 24 generates the difference image data 806 showing the difference between the master image data 804 and the read image data 803 (step S14).

Subsequently, the image processing unit 25 performs image processing on the difference image data 806 (step S15) to generate edge-enhanced image data 807. The details of image processing will be described later.

Next, the wrinkle determination unit 26 executes the wrinkle determination process based on the edge-enhanced image data 807 (step S16). The details of the wrinkle determination process will be described later.

The output unit 27 outputs the inspection result information 808 indicating the presence or absence of wrinkles (step S17). The operation unit 15 of the image forming apparatus 10 displays the received inspection result information 808. This allows the user to check for wrinkles on the paper after printing and, in some cases, stop printing.

FIG. 7 is a diagram showing an example of the flow of the alignment process.

In the alignment process (step S13) of the inspection process, the alignment processing unit 23 detects a point corresponding to the reference point of the master image data 804 from the scanned image data 803 (step S131).

Specifically, the alignment processing unit 23 performs pattern matching with the coordinates of the reference point set in the master image data 804 on the read image data 803 with a region in a certain range centered on the reference point. .. Then, the alignment processing unit 23 searches the scanned image data 803 for a region having the highest degree of matching with the image in a certain range region centered on the reference point of the master image data 804 from the result of pattern matching, and searches for the region of the region. The center point is the corresponding point in the scanned image data 803. However, the search method is not limited to this method, and other methods may be used.

Next, the alignment processing unit 23 compares the position of the reference point of the master image data 804 with the position of the corresponding point of the read image data 803, and calculates the amount of misalignment (step S132). Specifically, the amount of positional deviation between the coordinates of the reference point in the master image data 804 and the coordinates of the corresponding points in the scanned image data 803 is the X coordinate value (main scanning direction) and the Y coordinate value (secondary scanning direction). It is calculated for each of the above, and the position shift information 805 indicating the calculated position shift amount is generated.

FIG. 8 is a diagram for explaining an alignment method.

The alignment processing unit 23 applies an algorithm such as corner detection by a Harris operator to set a reference point at a characteristic location of the master image data 804. Further, the alignment processing unit 23 sets a sufficient number of reference points at arbitrary intervals in the sub-scanning direction in order to determine the movement of the paper in the transfer.

For example, as shown in FIG. 8, the alignment processing unit 23 may divide the image into six regions and set six reference points from (a) to (f). Further, when there are few features of the image in the divided area and there is no settable reference point in the area, the alignment processing unit 23 may set the reference point only in the settable area.

Although the method of dividing the image into a plurality of areas and setting the reference point is illustrated, another method may be used as long as the reference point for determining the position deviation can be obtained by transporting or printing.

FIG. 9 is a diagram for explaining a method of generating a difference image.

In step S14 of the inspection process, the difference image generation unit 24 calculates the difference between the read image data 803 and the master image data 804. At that time, the difference image generation unit 24 determines the position of the pixel to be compared with the pixel of the master image data 804 with reference to the position shift information 805.

For example, the difference image generation unit 24 determines which pixel difference is to be compared based on the amount of positional deviation between the coordinate value of the reference point 804a of the master image data and the coordinate value of the point 803a of the read image data. .. The generated difference image data 806 is image data showing the difference between the pixel values of each color (R, G, B) to be compared.

If the paper is wrinkled, it is considered that the wrinkles appear as a difference in the pixel values of the read image data 803 and the master image data 804. However, depending on how the wrinkles are broken and the content of the corresponding image, it is conceivable that the pixel value may be larger or the pixel value may be smaller when the wrinkles are generated.

Therefore, the difference image data 806 is an absolute value of the difference between the pixel values of each color. For example, for the pixels to be compared, the pixel value of the master image data 804 is (R, G, B) = (233,222,10), and the pixel value of the read image data 803 is (R, G, B) = (230). , 240, 30), the pixel value of the difference image data 806 is (R, G, B) = (| 233-230 |, | 222-240 |, | 10-30 |) = (3,20). , 20).

FIG. 10 is a diagram showing an example of an image processing flow.

In the image processing (step S15) of the inspection processing, the image processing unit 25 generates image data in which the 0 degree filter A is applied to the difference image data 806 (step S151). 0 degree is an angle with respect to the positive direction of the X axis on the XY plane consisting of the main scanning direction (X direction) and the sub scanning direction (Y direction) in printing. The 0 degree filter A is a filter that emphasizes the edge along the boundary line of the 0 degree angle.

Next, the image processing unit 25 generates image data in which the filter B of 45 degrees is applied to the difference image data 806 (step S152). The 45-degree filter B is a filter that emphasizes the edge along the boundary line of the 45-degree angle with respect to the positive direction of the X-axis.

Next, the image processing unit 25 generates image data in which the 90-degree filter C is applied to the difference image data 806 (step S153). The 90-degree filter C is a filter that emphasizes the edge along the boundary line of the 90-degree angle with respect to the positive direction of the X-axis.

Next, the image processing unit 25 generates image data in which the filter D of 135 degrees is applied to the difference image data 806 (step S154). The 135 degree filter D is a filter that emphasizes the edge along the boundary line of the 135 degree angle with respect to the positive direction of the X axis.

The order of each process from steps S151 to S154 may be different, and the image processing unit 25 may process the four processes in parallel.

Next, the image processing unit 25 synthesizes the four generated image data (step S155). In this way, the image processing unit 25 generates the edge-enhanced image data 807.

FIG. 11 is a first diagram for explaining a method of image processing.

The image processing unit 25 applies the (a) 0 degree filter A shown in FIG. 11 to (b) the difference image data 806, and the pixel value a of the filter A and the pixel value b of the difference image data 806 are described below. The value c of the pixel of interest is calculated as in Equation 1.

c = Σa × b = (-1) × 0 + (-1) × 1 + (-1) × 1 + ... + (-1) × 3 + (-1) × 0 = -21 (Equation 1)

In this case, (b) the pixel value of the difference image data 806 does not form an edge along an angle of 0 degrees, so that the pixel of interest is not emphasized and the pixel value is low.

FIG. 12 is a second diagram for explaining a method of image processing.

The image processing unit 25 applies (a) a 45-degree filter B shown in FIG. 12 to (b) the difference image data 806, and uses the pixel value a of the filter B and the pixel value b of the difference image data 806 to determine the following. The value c of the pixel of interest is calculated as in Equation 2.

c = Σa × b = (-1) × 0 + (-1) × 1 + 0 × 1 + ... + (-1) × 3 + (-1) × 0 = 56 (Equation 2)

In this case, (b) the pixel value of the difference image data 806 forms an edge along an angle of 45 degrees, so that the pixel of interest is emphasized and the pixel value is high.

The filters shown in FIGS. 11 and 12 are filters having a size of 5 pixels each in the vertical and horizontal directions. This size is an example, and is determined in advance by the administrator of the image forming system 1 in consideration of the printing environment, the characteristics of the image forming apparatus 10, the characteristics of wrinkles that are frequently formed, and the like.

FIG. 13 is a diagram showing an example of the result of image processing.

(A) The image data to which the 0 degree filter A is applied is the image data in which the edges along the 0 degree angle are emphasized. (B) The image data to which the filter B of 45 degrees is applied is the image data in which the edges along the angle of 45 degrees are emphasized.

(C) The image data to which the 90-degree filter C is applied is the image data in which the edges along the 90-degree angle are emphasized. (D) The image data to which the filter D of 135 degrees is applied is the image data in which the edges along the angle of 135 degrees are emphasized.

In the image processing step S155, the image processing unit 25 combines these four image data to generate (e) edge-enhanced image data 807. Specifically, the image processing unit 25 generates image data having the maximum value of each pixel value for each color of the four image data as the pixel value as the edge-enhanced image data 807.

Since wrinkles often form edges along various angles, the edge-enhanced image data 807 is image data in which the difference due to wrinkles is emphasized.

FIG. 14 is a diagram showing an example of the flow of the wrinkle determination process.

In the wrinkle determination process of step S16 of the inspection process, the wrinkle determination unit 26 extracts pixels having a pixel value of the first threshold value Th1 or more from all the pixels in the page of the edge-enhanced image data 807 (step S161). The first threshold value Th1 is set in advance in consideration of the accuracy of the reading device, the occurrence of wrinkles, and the like.

Next, the wrinkle determination unit 26 classifies the extracted plurality of pixels as a group of pixel sets in which the pixels whose distances from each other are equal to or less than the second threshold value Th2 are grouped together (step S162). The second threshold value Th2 is set in advance according to the occurrence of wrinkles and the like. If the second threshold Th2 is too large, the probability of determining a defect that is not a wrinkle is high, and conversely, if the second threshold Th2 is too small, the probability of not being able to determine a wrinkle even though it is actually a wrinkle is high. Since it will be higher, it will be decided in consideration of the trade-off between the two.

Subsequently, the wrinkle determination unit 26 calculates the horizontal length and the vertical length for each pixel set (step S163).

Next, the wrinkle determination unit 26 determines whether or not the horizontal length or the vertical length is the third threshold value Th3 or more (step S164). When the wrinkle determination unit 26 determines that the horizontal length or the vertical length is the third threshold value Th3 or more (step S164: Yes), the wrinkle determination unit 26 determines that the pixel set is a difference due to wrinkles (step S165).

Further, when the wrinkle determination unit 26 determines that the horizontal length or the vertical length is not equal to or greater than the third threshold value Th3 (step S164: No), the wrinkle determination unit 26 determines that the pixel set is a difference due to a defect other than wrinkles (step). S166).

Then, the wrinkle determination unit 26 determines whether or not all the pixel sets have been processed (step S167). When the wrinkle determination unit 26 determines that an unprocessed pixel set exists (step S167: No), the wrinkle determination unit 26 returns to step S163 and executes processing on the unprocessed pixel set.

When the wrinkle determination unit 26 determines that all the pixel sets have been processed (step S167: Yes), the wrinkle determination unit 26 ends the wrinkle determination process.

FIG. 15 is a diagram showing an example of the result of the wrinkle determination process.

At first glance, the pixel set 601 has a slight gap, and not all the pixels are in contact with each other. However, when the wrinkle determination unit 26 determines that the distance between the pixels is a distance equal to or less than the second threshold value Th2, the wrinkle determination unit 26 classifies the pixels as a group of pixel sets 601.

Further, if the horizontal length x1 or the vertical length y1 of the pixel set 601 is equal to or greater than the third threshold value Th3, the wrinkle determination unit 26 determines that the pixel set 601 is a difference due to wrinkles.

Even if the pixel value of the wrinkle is emphasized by image processing as in the pixel set 601 but the influence of the wrinkle on the pixel value is not necessarily large, a portion where the difference is less than the first threshold value Th1 may be included. Therefore, if it is determined that the distance between the two is equal to or less than the second threshold value Th2, it can be said that a method of classifying the pixels as a group of pixels and determining the length in each pixel set is a useful determination method.

If the horizontal length x2 and the vertical length y2 of the pixel set 602 are both less than the third threshold value Th3, the wrinkle determination unit 26 determines that the pixel set 602 is a difference due to a defect other than wrinkles.

In the case of defects other than wrinkles, such as the pixel set 602, the length is often shorter than that of wrinkles. It can be said that it is a method of evaluation by taking advantage of the characteristic that it usually has a certain length.

If the horizontal length x3 or the vertical length y3 of the pixel set 603 is equal to or greater than the third threshold value Th3, the wrinkle determination unit 26 determines that the pixel set 603 is a difference due to wrinkles. It is difficult to simply measure the length of the wrinkles because the wrinkles may be branched and do not necessarily have a simple line shape as in the pixel set 603. Therefore, it can be said that a method of determining based on the horizontal length and the vertical length is a highly practical determination method as a method of evaluating by taking advantage of the characteristic that wrinkles usually have a certain length.

According to the image forming system 1 according to the present embodiment, a part of the image of the difference image data is converted into the emphasized image data. This makes it possible to detect the difference even when the difference in pixel values generated by the poor condition such as wrinkles formed on the recording medium such as paper is small, so that the detection accuracy of the poor condition of the recording medium can be detected. Can be improved.

The image processing filter shown in this embodiment is an example, and may be other. For example, a Gabor filter may be used as a filter for emphasizing edges. A Gabor filter is a linear filter that extracts specific frequency components. Specifically, the angles with respect to the positive direction of the X axis on the XY plane consisting of the sub-scanning direction (X direction) and the main scanning direction (Y direction) in printing are 0 degrees, 45 degrees, 90 degrees, and 135 degrees. A Gabor filter is used to extract each frequency component.

An example of using four image processing filters is shown, but the number of filters may be other. As described above, the image processing unit 25 is a plurality of filters for emphasizing the edges along the boundary line of a specific direction, and is based on each of the plurality of filters in which the directions of the emphasized boundary lines are different from each other. Process the image. As a result, the image processing unit 25 can perform image processing that captures the characteristics of "wrinkles" that form edges along the boundaries in various directions.

(Second embodiment)
The second embodiment will be described below with reference to the drawings. The second embodiment is to determine whether or not there is a defect in the image due to a defective condition of the image forming apparatus such as a failure of a part or deterioration of consumables, in addition to determining whether or not the recording medium is in a defective condition, and an inspection. The point that the result is displayed on the terminal is different from the first embodiment. Therefore, in the following description of the second embodiment, only the differences from the first embodiment will be described, and the description of the first embodiment will be described for those having the same functional configuration as the first embodiment. The same reference numerals as those used in the above are given, and the description thereof will be omitted.

FIG. 16 is a diagram showing an example of the system configuration of the image forming system according to the second embodiment.

The image forming system 1 according to the present embodiment includes an inspection result management server 70. The inspection result management server 70 is communicably connected to the terminal device 40, the inspection device 20, and the like via the communication network 60.

The inspection result management server 70 manages the inspection result by the inspection device 20. Specifically, the inspection result management server 70 stores the inspection result information, searches for the inspection result information in response to a search request from the terminal device 40, and transmits the inspection result information to the terminal device 40.

FIG. 17 is a diagram showing an example of the functions of the image forming apparatus and the inspection apparatus according to the second embodiment.

The inspection device 20 according to the present embodiment includes a defect determination unit 28. The defect determination unit 28 determines whether or not there is a defect in the image due to a poor state of the image forming apparatus 10 based on the difference image data 806 generated by the difference image generation unit 24.

Further, the output unit 27 transmits the inspection result information 808 including the determination results of the wrinkle determination unit 26 and the defect determination unit 28 to the image forming apparatus 10 and the inspection result management server 70.

Further, when the operation unit 15 of the image forming apparatus 10 according to the present embodiment determines whether or not to temporarily stop printing based on the received inspection result information 808, and determines that the printing is temporarily stopped. Is to have the print stop unit 16 described later temporarily stop printing. Further, the operation unit 15 receives an operation of selecting whether to stop or continue printing from the user.

The image forming apparatus 10 according to the present embodiment includes a print stop unit 16. When the print stop unit 16 receives an instruction from the operation unit 15 to temporarily stop printing, the print stop unit 16 controls the image forming unit 13 so as to temporarily stop printing. Further, when the operation unit 15 receives an operation from the user to stop or continue printing, the print stop unit 16 stops printing or continues printing according to the operation.

FIG. 18 is a diagram showing an example of a flow of inspection processing according to the second embodiment.

In the inspection process according to the present embodiment, following the wrinkle determination process in step S16, the defect determination unit 28 determines the defect (step S21). Specifically, the conditions corresponding to each of the types of defects (dot stains, white spots, main scanning colored streaks, main scanning white streaks, sub-scanning colored streaks, sub-scanning white streaks, etc.) and the set coefficients ( Defect level) and is preset.

Based on the difference image data 806 generated in step S14, the defect determination unit 28 determines a part of the entire difference image area that matches the set conditions as the defect portion. The conditions corresponding to the defects are predetermined based on the density difference threshold value and the area threshold value of the pixels. Further, each threshold value, coefficient, etc. can be appropriately changed by the user.

The order of the wrinkle determination process in step S16 and step S21 may be reversed. Further, the inspection device 20 may execute the processes of step S16 and step S21 in parallel.

The inspection result information output in step S17 includes a wrinkle determination result and a defect determination result. The defect determination result includes information indicating the type and level of the defect.

FIG. 19 is a diagram showing an example of an inspection result display screen according to the second embodiment.

The terminal device 40 sends a search request to the inspection result management server 70 in response to the user's operation, and when the inspection result information is received as a response, the terminal device 40 displays the inspection result display screen shown in FIG. The terminal device 40 is an example of a display unit that displays information output by the output unit 27 of the inspection device 20.

On the inspection result display screen 700, the job ID, print date / time, threshold name, total number of pages, number of defective pages, number of wrinkled pages, and read information are collected in the list display area D1 on the left side of the screen. / Information about the job such as unread flag is displayed in a list. Further, the terminal device 40 may display information indicating in which job the page identification information is printed or not printed on the printed matter.

The number of wrinkled pages is the number of wrinkled pages in each job. The list display area D1 can be sorted in ascending order and descending order for each item.

Further, the terminal device 40 has information for specifying a job that is set to print page identification information, information for specifying a job that has a margin to be cut on paper and has page identification information printed in the margin, and the like. May be displayed. The unread flag 706 is displayed at the end of each job line. The unread flag 706 may have a different color depending on whether there is a defect or not.

Further, above the list display area D1, an "all jobs" tab 701, a "defective job" tab 702, an update button 703, an export button 704, and a search button 705 are displayed.

The "All Jobs" tab 701 is a tab for displaying inspection result information of all print jobs for each print job. The “Defect Job” tab 702 is a tab for displaying print jobs containing defects.

When the user presses the update button 703, the terminal device 40 acquires the latest inspection result information from the inspection result management server 70 and displays it in the list display area D1. Further, when the user selects the defect inspection information for each job displayed in the list and presses the export button 704, the inspection result management server 70 generates detailed information for each job in a file format such as HTML and is a terminal. It is transmitted to the device 40.

Further, when the user presses the search button 705, the terminal device 40 displays a dialog for specifying the search condition, receives the user's operation, and sends the specified search condition to the inspection result management server 70. , Acquire the search result by the inspection result management server 70.

The inspection result display screen 700 has a detailed display area D2 and a preview display area D3 on the right side of the screen.

The detail display area D2 includes the print date and time of the defective page, the number of copies of the defective or wrinkled page (the number of copies including the defective page or the wrinkled page when printing the same document in multiple copies in one job). ), The page number of the defective or wrinkled page, and an icon indicating the type of defect or wrinkle contained. The types of icons are, for example, dot stains, white spots, main scanning colored streaks, main scanning white streaks, sub-scanning colored streaks, sub-scanning white streaks, or wrinkles.

Upon receiving the selection of the row of the defective or wrinkled page of the defect detail displayed in the detailed display area D2, the terminal device 40 displays the scanned image data of the defective or wrinkled page in the preview display area D3. .. The defect or wrinkle occurrence location included in the scanned image data is surrounded by a color frame having the same color as the icon indicating the corresponding defect type or wrinkle.

For example, the color frame 707 is an example of a color frame showing a sub-scanned colored streak, and the color frame 708 is an example of a color frame showing a wrinkle.

On the inspection result display screen 700, the user can see how the poor condition of the recording medium such as wrinkles and the defect of the image due to the poor condition of the image forming apparatus 10 such as the failure of parts and the deterioration of consumables are found in the past jobs. It is possible to easily confirm whether or not it has occurred.

Next, the operation of the image forming apparatus 10 according to the present embodiment will be described.

FIG. 20 is a diagram showing an example of a flow of print stop processing according to the second embodiment.

When printing is executed, the image forming apparatus 10 receives inspection result information 808 from the inspection apparatus 20 for each page included in the job (step S301). The operation unit 15 determines whether or not the inspection result information 808 indicates “with” wrinkles (step S302). When the operation unit 15 determines that the inspection result information 808 indicates “with” wrinkles (step S302: Yes), the operation unit 15 determines whether or not the print job being executed is set to be paused when the inspection result information 808 is “with” wrinkles. (Step S303).

When the operation unit 15 determines that the job is temporarily stopped when there are wrinkles (step S303: Yes), the operation unit 15 displays a print stop confirmation screen (step S306). The print stop confirmation screen will be described later.

If the operation unit 15 determines that the inspection result information 808 indicates "none" (step S302: No), or determines that the job is not paused when the inspection result information 808 is "present" (step S303: No). No), it is determined whether or not the inspection result information 808 indicates “with” a defect (step S304).

The operation unit 15 determines whether or not the inspection result information 808 indicates “with” a defect (step S304). When the operation unit 15 determines that the inspection result information 808 indicates "presence" (step S304: Yes), the operation unit 15 determines whether the defect is at a level exceeding the threshold value or is a defect of a specific type. (Step S305). Thresholds and specific types of defects are preset.

When the operation unit 15 determines that the defect is at a level exceeding the threshold value or is a defect of a specific type (step S305: Yes), the operation unit 15 displays a print stop confirmation screen (step S306).

FIG. 21 is a diagram showing an example of a print stop confirmation screen according to the second embodiment.

The print stop confirmation screen 710 includes information indicating an error type code, an ID of a suspended print job, the number of copies being printed, the number of pages, and the like, and a print continuation button 711 and a job stop button 712.

Returning to FIG. 20, the operation unit 15 determines whether or not an operation for stopping the execution of the job has been received (step S307). The operation of stopping the execution of the job is an operation of pressing the job stop button 712 of the print stop confirmation screen 710.

When it is determined that the operation unit 15 has received an operation to stop the execution of the job (step S307: Yes), the print stop unit 16 stops the execution of the job (step S308).

Further, when the operation unit 15 determines that the operation for stopping the execution of the job has not been received (step S307: No), the operation unit 15 determines whether or not the operation for continuing the execution of the job has been received (step S309). The operation of continuing the execution of the job is an operation of pressing the print continuation button 711 on the print stop confirmation screen 710.

When the operation unit 15 determines that the operation for continuing the execution of the job has not been received (step S309: No), the operation unit 15 returns to the process of step S307. Further, when it is determined that the operation unit 15 has received an operation to continue the job execution (step S309: Yes), the print stop unit 16 continues the job execution (step S310).

Further, the operation unit 15 determines that the inspection result information 808 indicates "none" (step S304: No), or determines that the defect is not at a level exceeding the threshold value and is not a specific type of defect. Then (step S305: No), the print stop unit 16 continues the execution of the print job without pausing (step S310).

Since poor condition of the recording medium such as wrinkles is a fatal defect as a final product, it is usually necessary to discard and reprint. In addition, once a poor condition of a recording medium such as wrinkles occurs, it often occurs continuously thereafter. Therefore, according to the image forming system 1 according to the present embodiment, when it is determined that there is a state defect of the recording medium such as wrinkles during printing, the running print job is temporarily stopped and the user operates. To stop or continue the execution of the job. Therefore, by detecting the occurrence of a state defect of the recording medium such as wrinkles and stopping printing, the user can avoid waste such as reprinting and obtain an opportunity to reinsert the paper.

While the poor condition of the recording medium is fatal, the defects of the image due to the poor condition of the image forming apparatus 10 range from minute to fatal. Therefore, according to the image forming system 1 according to the present embodiment, all the images are printed out without stopping the job according to the type, level, etc. of the defect, and the user visually confirms the image containing the defect. You can decide whether to reprint the printed paper.

Further, according to the image forming system 1 according to the present embodiment, even if both the poor condition of the recording medium such as wrinkles and the defective image due to the poor condition of the image forming apparatus 10 can occur, they can occur respectively. Appropriate control can be performed.

The method for generating the master image data 804 described above is an example and may be used elsewhere. For example, the master image data 804 may be data (another file) different from the data used for the job as long as it is an image that serves as a reference for comparison with the scanned image data 803. For example, the image forming apparatus 10 or another apparatus may generate image data in CMYK format or RGB format and input the image data to the inspection apparatus 20. In that case, the master image generation unit 21 converts the input image data into RGB format if it is in CMYK format, and if the input image data is in RGB format, the master image data is used as it is. It may be 804.

Further, the image forming apparatus 10 may print an image on a recording medium in advance, scan the printed recording medium, and input the image data obtained into the inspection apparatus 20. In that case, the image forming apparatus 10 or the inspection apparatus 20 may display the image data obtained by scanning by the preview display function for confirming the master image data or the like. Then, it is desirable to use the image data whose wrinkles and the like have been confirmed by the operator as the master image data 804.

Further, the image forming apparatus 10 and the inspection apparatus 20 combine the disclosed processing steps, for example, the processing steps of the flow disclosed in FIGS. 6, 7, 10, 18, 18 or 20 in various combinations. Can be configured to be shared. Further, each element of the image forming apparatus 10 and the inspection apparatus 20 may be integrated into one apparatus or may be divided into a plurality of apparatus.

In certain embodiments, the inspection device 20 may be configured as an information processing system including a plurality of computing devices such as a server cluster. The plurality of computing devices are configured to communicate with each other via any type of communication link, including networks, shared memory, and the like, and the processes disclosed herein may be performed.

Each function of the embodiment described above can be realized by one or more processing circuits. Here, the "processing circuit" as used herein is a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, or a processor designed to execute each function described above. It shall include devices such as ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array) and conventional circuit modules.

Although the present invention has been described above based on each embodiment, the present invention is not limited to the requirements shown in the above embodiments. With respect to these points, the gist of the present invention can be changed to the extent that the gist of the present invention is not impaired, and can be appropriately determined according to the application form thereof.

1 Image forming system 10 Image forming device 11 RIP image receiving unit 12 RIP image transmitting unit 13 Image forming unit 14 Reading unit 15 Operation unit 16 Printing stop unit 20 Inspection device 21 Master image generation unit 22 Read image acquisition unit 23 Alignment processing unit 24 Difference image generation unit 25 Image processing unit 26 Wrinkle determination unit 27 Output unit 28 Defect determination unit 30 DFE
40 Terminal equipment 50 Job management server 60 Communication network 70 Inspection result management server

Japanese Unexamined Patent Publication No. 2006-084595

Claims (14)

A difference image generator that generates difference image data showing the difference between the scanned image data obtained by reading the recording medium on which the image is formed and the master image data used as a reference for comparison.
An image processing unit that converts the difference image data into image data in which a part of the image is emphasized, and
An output unit for outputting information indicating the presence or absence of a state defect of the recording medium based on the converted difference image data is provided.
Inspection equipment. The image processing unit executes a filtering process for emphasizing edges included in the difference image data.
The inspection device according to claim 1. The image processing unit is a plurality of filters for emphasizing edges forming a boundary line having a specific orientation, and is applied to each of a plurality of filters having different orientations of the boundary lines formed by the emphasized edges. A plurality of image data are generated based on the above, and the generated plurality of image data are combined.
The inspection device according to claim 2. The plurality of filters are Gabor filters having different frequency components to be extracted.
The inspection device according to claim 3. The poor condition of the recording medium is a wrinkle generated on the recording medium.
The inspection device according to any one of claims 1 to 4. In the difference image data obtained by converting some of the pixel values, a pixel set including pixels having a pixel value equal to or higher than a predetermined threshold is determined, and whether or not the determined pixel set is a difference due to wrinkles is determined. Equipped with a wrinkle judgment unit for judgment
The output unit outputs the information indicating the presence or absence of wrinkles on the recording medium based on the determination result of the wrinkle determination unit.
The inspection device according to any one of claims 1 to 5. The wrinkle determination unit determines that the recording medium has wrinkles when the horizontal length or the vertical length of each pixel set is equal to or greater than a predetermined threshold value.
The inspection device according to claim 6. A wrinkle determination unit that determines whether or not the recording medium is in a bad state based on the difference image data,
Further, a defect determination unit for determining the presence or absence of a defect in the image due to a state defect of the image forming apparatus that formed the image based on the difference image data is provided.
The output unit outputs information indicating the presence or absence of a defect in the image due to the presence or absence of a state defect of the recording medium or the state defect of the image forming apparatus.
The inspection device according to any one of claims 1 to 5. An image forming unit that forms an image on a recording medium,
A reading unit that reads a recording medium on which an image is formed by the image forming unit,
A difference image generation unit that generates difference image data indicating the difference between the scanned image data read by the reading unit and the master image data that serves as a reference for comparison.
An image processing unit that converts the difference image data into image data in which a part of the image is emphasized, and
An output unit that outputs information indicating the presence or absence of a state defect of the recording medium based on the converted difference image data, and an output unit.
When the information output from the output unit indicates that the recording medium has a state defect, a print stop unit for stopping a running print job is provided.
Image formation system. Further provided with an operation unit that accepts an operation as to whether or not to continue the print job when the information output from the output unit indicates that the recording medium has wrinkles.
When the information output from the output unit indicates that the recording medium has a state defect, the print stop unit suspends the printing job being executed, and the operation unit accepts the operation. Continuing or suspending the suspended print job, depending on the situation.
The image forming system according to claim 9. The output unit further outputs information indicating the type or level of defects existing in printing based on the difference image data generated by the difference image generation unit.
When the information output from the output unit indicates that a defect exists in the print, the print stop unit stops the print job according to the type or level of the defect.
The image forming system according to claim 9 or 10. A wrinkle determination unit that determines whether or not the recording medium is in a bad state based on the difference image data,
A defect determination unit that determines, based on the difference image data, whether or not there is a defect in the image due to a state defect of the image forming apparatus that formed the image.
A display unit for displaying the information output by the output unit is further provided.
The output unit outputs information indicating the presence or absence of a defect in the image due to the presence or absence of a state defect of the recording medium or the state defect of the image forming apparatus.
The image forming system according to any one of claims 9 to 11. A step of generating a difference image data showing a difference between a scanned image data obtained by reading a recording medium on which an image is formed and a master image data as a reference for comparison, and a step of generating a difference image data.
A step of converting the difference image data into image data in which a part of the image is emphasized, and
A step of outputting information indicating the presence or absence of a state defect of the recording medium based on the converted difference image data is provided.
Inspection methods. On the computer
A step of generating a difference image data showing a difference between a scanned image data obtained by reading a recording medium on which an image is formed and a master image data as a reference for comparison, and a step of generating a difference image data.
A step of converting the difference image data into image data in which a part of the image is emphasized, and
A step of outputting information indicating the presence or absence of a state defect of the recording medium based on the converted difference image data, and
A program to execute.

Images