JP7456272B2 - Image inspection device and image forming system - Google Patents

Description

The present invention relates to an image inspection device and an image forming system including the image inspection device.

2. Description of the Related Art Image processing apparatuses that use GPUs (Graphics Processing Units) for graphic processing of image data are known. In addition, in image processing devices, GPUs are used as GPGPUs (General-Purpose Computing on Graphics Processing units) that are used for calculation purposes other than graphic processing. With this configuration, higher processing performance can be obtained compared to processing using only a CPU (Central Processing Unit).

In general, GPUs are faster at graphics-related processing such as resolution conversion and image rotation than CPUs. Further, the CPU temporarily stores and processes data in a RAM (Random Access Memory) (main memory, system memory), and the GPU stores and processes data in a video memory such as a VRAM (Video Random Access Memory). For example, when performing graphics-related calculations, which the GPU is good at, it is necessary to copy data that has been preprocessed by the CPU from the main memory to the video memory. The time to copy this image data is called overhead, and is required in addition to the actual processing time. Furthermore, the copied data is stored in the cache memory of the GPU and processed. When data is stored from the video memory to the cache memory, the next data can be stored faster once the data has been stored than when nothing is stored in the cache memory. Then, the cache memory is usually cleared after a series of processing is completed.

Japanese Patent Application Publication No. 2017-164914 Japanese Patent Application Publication No. 2011-204052

In general image inspection, a correct image and a test image are compared and the difference is extracted as a defect. Therefore, when using a GPU for image inspection, it is necessary to copy the image data to be processed by the GPU from the main memory to the video memory.

That is, in image inspection, when inspecting an image printed on the first sheet of recording material, it is necessary to process the correct image and the inspection image by the GPU. On the other hand, when inspecting images printed on the second and subsequent sheets of recording material, the cache data processed during the inspection of the first sheet can be used, so the processing load on the GPU is small. Therefore, in image inspection, the processing load on the GPU differs between the first image and the second and subsequent images. As a result, in the image inspection device, the processing time of the first image, which has a large processing load, becomes the limiting factor.
Therefore, in an image inspection device, it is required to reduce the processing load on the GPU during image inspection of the first sheet.

In order to solve the above-mentioned problems, the present invention provides an image inspection apparatus and an image forming apparatus that can reduce the processing load on a second processor (for example, GPU) used in image inspection.

The image inspection apparatus of the present invention includes a reading section that reads an image printed on a recording material, a first processor, a second processor having higher image processing ability than the first processor, and a first processor used by the first processor. 1 memory and a second memory used by a second processor, and the first processor and the second processor cooperate to read an image printed on a recording material with a reading unit. and an inspection section that performs an image inspection that compares the image data of the inspection image obtained by the test with the image data of the correct image to extract defects in the inspection image. Before executing the image inspection, the inspection unit executes a dummy inspection in which image data of the correct images are compared with each other.
Further, an image forming system of the present invention includes an image forming apparatus and the image inspection apparatus described above.

According to the present invention, it is possible to provide an image inspection apparatus and an image forming apparatus that can reduce the processing load on a second processor during image inspection.

1 is a diagram showing a schematic configuration of an image forming system. FIG. 1 is a block diagram showing the main system configuration of an inkjet recording apparatus. FIG. 2 is a block diagram showing the main system configuration of an inspection section of the image inspection apparatus. It is a flowchart of an image inspection method. It is a flowchart of an image inspection method.

Examples of modes for carrying out the present invention will be described below, but the present invention is not limited to the following examples.

1. Image forming system
An embodiment of an image forming system of the present invention will be described below.
A schematic configuration of an image forming system is shown in Fig. 1. The image forming system 1 shown in Fig. 1 includes a paper feeder 10, an inkjet recording device 20, and an image inspection device 30. Note that in the following description, an image forming system using an inkjet recording device will be described, but the image forming system is not limited to an inkjet recording system and may include an image forming device of another system.

[Paper feeding device]
The paper feeding device 10 holds the recording material S on which an image is to be formed, and supplies it to the image forming section 200 during image formation. Paper feeding device 10 includes a paper feeding tray 11 and a transport section 12.
The paper feed tray 11 is plate-shaped and can hold a plurality of recording materials S. The paper feed tray 11 moves up and down depending on the amount of recording material S placed thereon. The paper feed tray 11 is held at a position where the uppermost recording material S is transported by the transport section 12 .

The conveyance unit 12 includes a plurality of (two in FIG. 1) rollers 121 and 122 and a ring-shaped belt 123. The belt 123 is rotationally driven by a plurality of rollers 121 and 122. The conveyance section 12 includes a conveyance mechanism that conveys the recording material S on the belt 123 and a supply section that delivers the uppermost recording material S placed on the paper feed tray 11 to the belt 123. The conveyance unit 12 conveys the recording material S transferred to the belt 123 by the supply unit as the belt 123 rotates.

[Inkjet recording device]
The inkjet recording apparatus 20 includes an image forming section 200 and a control section 50. The inkjet recording apparatus 20 transports the recording material S from the paper feeding device 10 to the image forming section 200 under the control of the control section 50 . Then, an image is formed on the conveyed recording material S by the image forming section 200, and the recording material S on which the image has been formed is conveyed to the image inspection apparatus 30.

The image forming unit 200 forms an image on the recording material S by discharging ink such as UV ink onto the recording material S. The image forming section 200 includes an image forming drum 21 , a delivery unit 22 , a recording material heating section 23 , a plurality of head units 24 , an irradiation section 25 , and a delivery section 26 .

The image forming drum 21 carries a recording material S along its cylindrical outer peripheral surface, and conveys the recording material S as it rotates. The conveying surface of the image forming drum 21 faces the recording material heating section 23 , the plurality of head units 24 , and the irradiation section 25 . The image forming drum 21 performs processing related to image formation on the recording material S being conveyed.

The delivery unit 22 is provided between the image forming drum 21 and the conveying section 12 of the paper feeding device 10. The delivery unit 22 delivers the recording material S transported by the transport section 12 to the image forming drum 21 . The delivery unit 22 includes a swing arm portion 221, a cylindrical delivery drum 222, and the like. The swing arm section 221 supports one end of the recording material S conveyed by the conveyance section 12. The delivery drum 222 delivers the recording material S carried by the swing arm section 221 to the image forming drum 21. The delivery unit 22 picks up the recording material S on the conveyance section 12 with the swing arm section 221 and delivers it to the delivery drum 222, thereby guiding the recording material S in a direction along the outer peripheral surface of the image forming drum 21 to form an image. Deliver it to drum 21.

The recording material heating section 23 heats the recording material S carried on the image forming drum 21 . The recording material heating unit 23 includes, for example, an infrared heater and the like, and generates heat in response to energization. The recording material heating section 23 is provided near the outer peripheral surface of the image forming drum 21 and upstream of the head unit 24 along the direction in which the recording material S is conveyed by the rotation of the image forming drum 21 . The heat generation of the recording material heating section 23 is controlled by the control section 50 so that the recording material S carried by the image forming drum 21 and passing near the recording material heating section 23 reaches a predetermined temperature.

The plurality of head units 24 eject ink of each color of C (cyan), M (magenta), Y (yellow), and K (black) onto the recording material S carried on the image forming drum 21. Then, an image is formed on the recording material S. Head units 24 are provided separately for each of the CMYK colors. In FIG. 1, head units 24 corresponding to each color of YMCK are provided in this order along the conveyance direction of the recording material S conveyed as the image forming drum 21 rotates.

Note that the head unit 24 is provided with a length (width) that covers the entire recording material S in a direction (width direction) perpendicular to the conveyance direction of the recording material S. That is, the inkjet recording device 20 is a one-pass line head type inkjet recording device. The head unit 24 can configure a line head by arranging a plurality of inkjet heads.

The irradiation unit 25 irradiates energy rays for curing the ink ejected onto the recording material S. The irradiation unit 25 includes, for example, a fluorescent tube such as a low-pressure mercury lamp. The irradiation unit 25 irradiates energy rays such as ultraviolet rays by causing a fluorescent tube to emit light. The irradiation section 25 is provided near the outer circumferential surface of the image forming drum 21 and downstream of the head unit 24 with respect to the direction in which the recording material S is conveyed by the rotation of the image forming drum 21 . The irradiation unit 25 irradiates the recording material S carried by the image forming drum 21 and on which ink has been ejected with energy rays, thereby curing the ink on the recording material S.

Fluorescent tubes that emit ultraviolet light include low-pressure mercury lamps, mercury lamps with an operating pressure of several hundred Pa to 1 MPa, light sources that can be used as germicidal lamps, cold cathode tubes, ultraviolet laser light sources, metal halide lamps, light-emitting diodes, etc. can be mentioned. Among these, a light source (for example, a light emitting diode) that can irradiate ultraviolet rays with higher intensity and consumes less power is more desirable. Further, the energy rays are not limited to ultraviolet rays, and may have the property of curing the ink depending on the properties of the ink. In the irradiation unit 25, the light source may be replaced depending on the wavelength of the energy ray.

The delivery unit 26 transports the recording material S, which has been irradiated with energy rays by the irradiation unit 25, from the image forming drum 21 to the image inspection device 30. The delivery unit 26 includes a plurality of (two in FIG. 2) rollers 261 and 262, a ring-shaped belt 263, and the like. The belt 263 is rotationally driven by a plurality of rollers 261 and 262. The delivery unit 26 includes a transport mechanism that transports the recording material S on a belt 263, and a cylindrical delivery drum 264 that delivers the recording material S from the image forming drum 21 to the transport mechanism. The delivery unit 26 transports the recording material S delivered to the belt 263 by the delivery drum 264 using the belt 263 and sends it out to the image inspection apparatus 30 .

The control section 50 controls the operation of each section of the inkjet recording apparatus 20 and oversees the overall operation. The control unit 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Details of the control unit 50 will be described later.

The inkjet recording device 20 uses, for example, UV ink. In a state where UV ink is not irradiated, the phase changes between a gel state and a liquid (sol) state depending on the temperature. UV ink has a phase change temperature of, for example, about 100° C., and uniformly liquefies (sols) when heated above this phase change temperature. On the other hand, this ink gels at temperatures below the phase change temperature, including around normal room temperature (0° C. to 30° C.).

(System configuration of inkjet recording device)
FIG. 2 shows a block diagram showing the main system configuration of the inkjet recording apparatus 20.
The inkjet recording device 20 includes a conveyance drive section 581 and a rotary encoder 582 provided in the conveyance section 58, a head control section 241 and a head drive section 242 provided in the head unit 24, a control section 50, and an image processing section 55. , an operation display section 56 , an input/output interface 57 , a bus 59 , and the like.

The transport drive unit 581 supplies a drive signal to the transport motor based on a control signal supplied from the control unit 50, and rotates the drive roller at a predetermined rotational speed, thereby moving the transport belt at a predetermined moving speed.

The head control unit 241 outputs various control signals and image data to the head drive unit 242 at appropriate timings according to the control signal from the control unit 50 and the count number of pulse signals input from the rotary encoder 582. do.
The head drive section 242 supplies a drive signal for deforming the piezoelectric element to the recording element of the head unit 24 in accordance with the control signal and image data input from the head control section 241, and supplies ink from the opening of each nozzle. Discharge.

The control unit 50 includes a CPU 51, a RAM 52, a ROM 53, and a storage unit 54.
The CPU 51 reads various control programs and setting data stored in the ROM 53, stores them in the RAM 52, and executes the programs to perform various calculation processes. Further, the CPU 51 centrally controls the entire operation of the inkjet recording apparatus 20.
The RAM 52 provides a working memory space for the CPU 51 and stores temporary data. RAM 52 may include nonvolatile memory.
The ROM 53 stores various control programs executed by the CPU 51, setting data, and the like. Note that in place of the ROM 53, a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 54 stores a print job (image recording command) input from the external device 100 via the input/output interface 57 and image data related to the print job. As the storage unit 54, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

The image processing section 55 performs predetermined image processing on the image data stored in the storage section 54 under the control of the control section 50 and causes the storage section 54 to store the image data after the image processing. Image processing performed by the image processing unit 55 includes RIP (Raster Image Processor) processing, which converts PDL (Page Description Language) data input from the external device 100 and stored in the storage unit 54 into raster format image data; There is a color conversion process that converts image data of each color component such as Red), G (Green), and B (Blue) into image data of each color component such as Y, M, C, and K.

The Y, M, C, and K image data generated in the image processing section 55 are supplied to the head unit 24 corresponding to the ink color among the four head units 24. Then, under the control of the control section 50 and the head control section 241, the head unit 24 performs an ink ejection operation based on the supplied image data.

Note that the image processing section 55 may not be provided and the various image processing described above may be performed in the control section 50. Alternatively, the various types of image processing described above may be performed in the external device 100 provided outside the inkjet recording apparatus 20, and the processed image data may be stored in the storage unit 54.

The operation display unit 56 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as operation keys and a touch panel placed over the screen of the display device. The operation display unit 56 displays various information on the display device, and also converts a user's input operation on the input device into an operation signal and outputs it to the control unit 50.

The input/output interface 57 mediates data transmission and reception between the external device 100 and the control unit 50. The input/output interface 57 is configured of, for example, one of various serial interfaces, various parallel interfaces, or a combination thereof.

The bus 59 is a path for transmitting and receiving signals between the control unit 50 and other components.
The external device 100 is, for example, a personal computer, and supplies print jobs, image data, etc. to the control unit 50 via an input/output interface 57.

Note that the components of the inkjet recording apparatus 20 are not limited to those described above, and other components may be provided as necessary. For example, a sensor (abnormality detection section) may be provided on the upstream side of the head unit 24 in the transport direction to detect a placement abnormality such as floating of the recording material S, a foreign object attached to the recording material S, etc. .

[Inspection equipment]
The image inspection apparatus 30 of the image forming system 1 shown in FIG. It has a paper discharge tray 45 on which the material S is discharged, and an inspection section 40.

The image inspection device 30 uses a reading section 44 to read an image formed (printed) on the recording material S conveyed from the inkjet recording device 20, and the inspection section 40 inspects whether the read image is normal or abnormal. The recording material S conveyed to the image inspection device 30 is a printed matter with an image formed on both sides or one side.

The reading unit 44 includes an optical sensor such as an image sensor and a colorimeter such as a spectrophotometer. For example, the reading unit 44 projects light onto the surface of the recording material S and reads reflected light from the recording material S as image data. The reading unit 44 reads the image data of the recording material S in this way, thereby acquiring read image data. The reading unit 44 reads the recording material S conveyed through the conveyance path 41 from above the conveyance path 41 . The reading section 44 outputs the read image data of the recording material S to the inspection section 40 .

In the image inspection apparatus 30 , the conveyance path 41 is connected to a reversing conveyance path 42 that branches downstream of the reading section 44 and joins the conveyance path 41 upstream of the image inspection apparatus 30 . The reversing conveyance path 42 is provided with a reversing section 43 for reversing the front and back sides of the recording material S. The recording material S reversed by the reversing unit 43 is returned to the upstream side of the transport path 41 through the reversing transport path 42 . The recording material S inspected by the image inspection device 30 is discharged to a paper discharge tray 45 (an example of a paper discharge section). Note that if reading sections are provided above and below the conveyance path 41, the reversal conveyance path 42 is not necessary.

If there is only one paper ejection tray 45, as in the image inspection apparatus 30 shown in FIG. 1, normal recording materials and abnormal recording materials are mixed and ejected. In this case, the normal recording material and the abnormal recording material are each discharged with a slight shift in the direction orthogonal to the direction in which they are discharged. Note that the recording material S is conveyed to either the paper ejection tray where the recording material S (waste paper) whose image is determined to be abnormal by the image inspection device 30 is ejected, the paper ejection tray 45, or another paper ejection tray. A switching unit may be provided to switch the conveyance direction of the recording material S so that the conveyance direction of the recording material S is changed.

The inspection section 40 stores the read image data input from the reading section 44 and performs an image inspection of the read image data. For example, if the inspection unit 40 does not detect any abnormalities such as stains, streaks, or positional deviations in the read image data of an image printed on the recording material S, the inspection unit 40 determines that the image is a normal image. Furthermore, when the inspection unit 40 detects an abnormality that satisfies the conditions in the read image data, it determines this image as an abnormal image.

The inspection unit 40 determines whether the image is normal or abnormal in the image inspection described above by comparing the correct image with the read image of the image formed on the recording material S. The image data of the correct image (correct image data) is stored in the storage unit 54 (FIG. 2) or the like in the control unit 50 of the inkjet recording apparatus 20. For this reason, the inspection unit 40 reads the correct image data from the storage unit 54, compares it with the image data of the read image (read image data), and performs an image inspection.

The image inspection device 30 also outputs the results of the image inspection to the inkjet recording device 20. The inkjet recording device 20 can display the results of the image inspection on the operation display unit 56 (Figure 2). This allows the user to check the results of the image inspection from the content displayed on the operation display unit 56 of the inkjet recording device 20.

(System configuration of inspection department)
FIG. 3 shows a block diagram showing the main system configuration of the inspection section 40 of the image inspection apparatus 30.
The inspection unit 40 includes a frame grabber 61, a chipset 62, a recording unit 63, a CPU 64, a system memory 65, a GPU 66, and a GPU memory 67.
The CPU 64 and the GPU 66 are processors that perform arithmetic processing in the inspection unit 40, with the CPU 64 corresponding to a first processor and the GPU 66 corresponding to a second processor having higher image processing ability than the first processor. Further, the system memory 65 is a memory (first memory) used by the first processor (CPU 64). The GPU memory 67 is a memory (second memory) used by the first processor (GPU 66).

The chipset 62 manages the exchange of data from devices installed in the inspection section 40 . For example, it manages data exchange among the CPU 64, system memory 65, GPU 66, frame grabber 61, and the like.
The frame grabber 61 is an input/output interface of the inspection section 40. The inspection unit 40 communicates with external equipment via the frame grabber 61. Then, the inspection unit 40 stores the information input via the frame grabber 61 in the recording unit 63 based on the management of the chipset 62. The frame grabber 61 is, for example, communicably connected to the reading section 44 and receives image data acquired by the reading section 44 . The frame grabber 61 is also communicably connected to, for example, the input/output interface 57 (FIG. 2) of the inkjet recording device 20, and receives image-processed image data processed by the image processing unit 55 of the inkjet recording device 20. Receive.

The recording unit 63 stores various control programs and setting data executed by the CPU 64. It also stores various information input via the frame grabber 61, such as the read image data acquired by the reading unit 44 and image-processed image data acquired from the memory unit 54 (Figure 2) of the control unit 50 of the inkjet recording device 20.

The CPU 64 reads various control programs and setting data stored in the recording unit 63, stores them in the system memory 65, executes the programs, and performs image inspection. System memory 65 is composed of RAM.
The GPU 66 stores the image data stored in the recording unit 63 and the system memory 65 in the GPU memory 67 according to instructions from the CPU 64, and performs image processing, image inspection, etc. on the image data.

The inspection unit 40 includes a CPU 64 and a GPU 66 as processors that perform arithmetic processing, so that the processing by the CPU 64 on data developed in the system memory 65 and the processing by the GPU 66 in relation to data developed in the GPU memory 67 are performed in cooperation with each other. It can be carried out. For example, image data processed by the CPU 64 is copied from the system memory 65 to the GPU memory 67 of the GPU 66. Further, the image data copied to the GPU memory 67 is stored in the cache memory of the GPU 66, and processed by the GPU 66.

In the inspection unit 40, two processors, a CPU 64 and a GPU 66, that perform arithmetic processing cooperate to perform image inspection. In the image inspection, an image formed by executing a print job in the inkjet recording device 20 is read by the reading unit 44 of the image inspection device 30, and image data for inspection of the formed image (inspection image data) is obtained. Then, by comparing this inspection image data with image data of a correct image that does not include an abnormality (correct image data), an abnormality in the inspection image is detected. The correct image data is registered in advance in the storage section 54 of the control section 50 and the recording section 63 of the inspection section 40 before executing the print job.

The inspection unit 40 also performs an image inspection (dummy inspection) using correct image data as inspection image data. In the dummy test, correct image data registered in advance in the storage section 54 of the control section 50 or the recording section 63 of the inspection section 40 is used instead of the read data of the image formed in the inkjet recording device 20. That is, in the dummy test, an image test is performed in which correct image data are compared with each other.

Reading of image data in a dummy test in the test section 40 is performed, for example, as follows.
First, the CPU 64 reads image data as a correct image from the recording section 63 and stores it in an arbitrary area of the system memory 65. Further, the CPU 64 reads image data as an inspection image from the recording section 63 and stores it in another area of the system memory 65. Next, each image data is stored in the GPU memory 67. Further, each image data stored in the GPU memory 67 is stored in a cache memory of the GPU 66, and processed by the GPU 66. After the series of processing is completed, the cache memory is cleared.

The CPU 64 and GPU 66 compare the image data and perform an image inspection. Note that in the image inspection process, the CPU 64 and the GPU 66 may perform parallel processing, and the processing performed by the GPU 66 may be part of the image inspection process. Image data stored in the GPU memory 67 may also be part of each data.

[Image inspection method (1)]
Next, image inspection using the above-described image forming system 1 will be described. A flowchart of the image inspection method is shown in FIG. In the following inspection method, an example will be described in which image data formed by the inkjet recording device 20 and acquired by the reading unit 44 is used as the correct image.

First, when the image inspection menu is selected by the user in the image forming system 1, the inkjet recording device 20 outputs an image for image inspection (proof image) (step S10). Proof image output is performed before actually executing the print job. In the proof image output, a test print of a proof image is performed on the recording material S using the inkjet recording device 20 in order to proofread the print.

Next, the user visually checks whether the proof image is a normal image (step S11).
If the image is not normal (NO in step S11), that is, if the outputted proof image includes an abnormal part, the user may perform various adjustments (mechanical adjustment, etc.) of the inkjet recording device 20 depending on the content of the abnormal part that has occurred. (Step S12).
The outputting of the proof image (step S10) and the determination of whether the image is normal (step S11) are repeated until the image is determined to be normal.

If the proof image is determined to be a normal image by visual inspection by the user (YES in step S11), the output proof image is saved as a correct image (step S13). The proof image may be read by passing it through the reading section 44 after being inspected by the user, or the proof image may be read by the reading section 44 in conjunction with the output of the proof image by the inkjet recording device 20. good. For example, a user supplies a recording material on which a proof image determined to be a normal image is printed to the reading section 44 of the image inspection apparatus 30, and the reading section 44 reads the proof image to generate read image data. Furthermore, each time the inkjet recording device 20 outputs a proof image, the reading unit 44 may read the proof image and generate read image data for all the proof images.
The read image data generated by the reading section 44 is sent to the inspection section 40 via the frame grabber 61. The inspection unit 40 stores the read image data of the proof image acquired from the reading unit 44 in the recording unit 63 as correct image data in the image inspection.

Next, a dummy test is performed using the correct image data acquired by the test unit 40 (step S14). The dummy test is executed using only the correct image data stored in the recording unit 63 of the testing unit 40. Note that in the dummy test, the data (cache data) stored in the cache memory is not cleared even after the dummy test is completed.
Note that in the dummy inspection, since copies of the same image data are compared, abnormalities are usually not detected.

Next, the image forming system 1 permits execution of the print job in the image forming system 1 (step S15). Then, the print job is executed in the inkjet recording device 20 of the image forming system 1 (step S16).
The above-mentioned dummy inspection is performed before executing the print job instructed by the user. That is, the image forming system 1 does not allow the inkjet recording device 20 to execute a print job until the dummy inspection is completed. For example, the image forming system 1 may stop the operation of the operation display unit 56 so as not to accept an operation by the user, or may suspend the operation of the paper feeder 10 or the image forming unit 200 in response to the received execution process. This is controlled by the control section 50. Therefore, after the dummy inspection is completed, the control unit 50 cancels the suspension, suspension, etc. of execution of the print job by the inkjet recording device 20. This allows the image forming system 1 to execute a print job.

Next, the image inspection device 30 performs an image inspection on the image formed by the inkjet recording device 20 (step S17). The image test here is a normal image test. For example, the image formed on the recording material S by the inkjet recording device 20 is read by the reading unit 44 of the image inspection device 30 to generate inspection image data. Then, the inspection section 40 acquires the inspection image data from the reading section 44 and compares it with the correct image data.

In this image inspection, for example, the inspection section 40 acquires inspection image data from the reading section 44 via the frame grabber 61 and stores it in the recording section 63. The CPU 64 reads the correct image data and the inspection image data from the recording section 63 and stores them in the system memory 65. Next, each image data is stored in the GPU memory 67. Further, each image data stored in the GPU memory 67 is stored in a cache memory of the GPU 66, and processed by the GPU 66.

In the conventional inspection method, when inspecting the first image, in addition to processing the above-mentioned inspection image data, the CPU 64 reads the correct image data from the recording unit 63 and stores it in the system memory 65, and the CPU 64 transfers it to the GPU 66. instructions and reading and storing correct image data from the system memory 65 to the GPU memory 67 are performed.

In contrast, in this inspection method, in the inspection unit 40, image data is read from the recording unit 63 in a dummy inspection performed before the execution of a print job, and is stored in the system memory 65 and GPU memory 67, and then stored in the cache memory of the GPU 66, where processing is performed by the GPU 66. Therefore, when storing data from the GPU memory 67 to the cache memory of the GPU 66, the storage of the inspection image data is faster than the storage of the correct image during dummy inspection. Therefore, in image inspection after the execution of a print job, the time required for image processing by the GPU 66 can be shortened. As a result, the time required for image inspection of the first sheet can be shortened.

Next, in the image forming system 1, the control unit 50 of the inkjet recording device 20 determines whether the print job is finished after the image inspection (step S18). If the print job is to be continued (NO in step S18), the process returns to step S16 and the print job is executed in the inkjet recording device 20.

When the print job is completed (YES in step S18), the cache data of the GPU 66 is erased (step S19). After the print job is finished, there is no need to perform image inspection, so the cache data is deleted. In accordance with this, the CPU 64 may erase the correct image data stored in the system memory 65. After erasing the cache data of the GPU 66, the processing according to this flowchart ends.

[Image inspection method (2)]
Next, as an image inspection method using the image forming system 1 described above, an example will be described in which a RIP-processed image (CMYK) of a document image input by a user in a print job is used as correct image data (RGB). A flowchart of the inspection method according to this example is shown in FIG. Note that in the flowchart shown in FIG. 5, the same processing as in the flowchart shown in FIG. 4 described above is performed except for the method of acquiring correct image data. Therefore, detailed description of the same processing as the flowchart shown in FIG. 4 described above will be omitted.

First, the image processing section 55 of the inkjet recording apparatus 20 performs RIP processing on the original image input by the user (step S20). The image processing unit 55 performs RIP processing on the document image data input by the user, thereby creating a raster image having information on each color component of CMYK for use in image formation in the inkjet recording device 20.

Next, the image processing unit 55 performs color conversion processing on the RIP-processed raster image (step S21). Generally, the read image data acquired by the reading unit 44 has information on each color component of RGB. On the other hand, the raster image used for image formation that has been subjected to RIP processing by the image processing unit 55 of the inkjet recording apparatus 20 has information on each color component of CMYK. That is, the RIP-processed raster image and the read image data, which is the inspection image, have different color component information. Therefore, the RIP-processed raster image cannot be used as a correct image for inspecting read image data.

Therefore, by performing color conversion processing on the RIP-processed raster image so that it has the same information on each RGB color component as the read image data, a color-converted raster image having information on each RGB color component is generated. . If it is a raster image after color conversion, it has the same information on each RGB color component as the read image data, so it can be used as a correct image for the read image data.

Note that the resolution may be changed in accordance with the color conversion of the raster image described above. The resolution of the read image data serving as the inspection image depends on the resolution of the reading section 44. For this reason, it is preferable that the color-converted raster image that is the correct image is also converted to the same resolution as the resolution of the reading unit 44. Further, in order to match the resolutions of the correct image and the test image, image adjustments such as vertical doubling, horizontal doubling, and tilting may be performed on each image. The GPU 65 may be used for image processing such as color conversion processing, resolution conversion, and image adjustment.

Next, the color-converted raster image is saved as a correct image (step S22). The data of the raster image (raster image after color conversion) that has been subjected to color conversion processing in the image processing section 55 is stored in the storage section 54 of the control section 50 . The inspection unit 40 acquires the color-converted raster image from the storage unit 54 of the control unit 50 and stores it in the recording unit 63 as correct image data in the image inspection.

Next, a dummy test is performed using the correct image data acquired by the test unit 40 (step S23). In the dummy test, the CPU 64 reads out the color-converted raster image data as correct image data from the recording unit 63 and stores it in the system memory 65 twice. That is, the CPU 64 reads the correct image data of the color-converted raster image data as the correct image from the recording unit 63. Then, the CPU 64 performs a dummy test by comparing the image data stored in the system memory 65.

Next, the image forming system 1 permits execution of the print job in the image forming system 1 (step S24). Then, the print job is executed in the inkjet recording device 20 of the image forming system 1 (step S25). The control unit 50 does not allow the inkjet recording device 20 to execute a print job until the dummy test is completed. The control unit 50 allows execution of the print job after the dummy inspection is completed.

Next, the image inspection device 30 performs an image inspection on the image formed by the inkjet recording device 20 (step S26). The image test here is a normal image test. For example, the image formed on the recording material S by the inkjet recording device 20 is read by the reading unit 44 of the image inspection device 30 to generate inspection image data. Then, the inspection section 40 acquires the inspection image data from the reading section 44 and compares it with the correct image data of the raster image data after color conversion.

Next, the image forming system 1 determines whether the print job has ended after the image inspection (step S27), and if the print job is to be continued (NO in step S27), the process returns to step S25 and the inkjet recording device 20 Execute the print job.

When the print job is finished (YES in step S27), the cache data of the GPU 66 is erased. (Step S28). The CPU 64 may erase the correct image data stored in the system memory 65. After deleting the cache data, the process according to this flowchart ends.

With the above method, a correct image can be obtained without outputting a proof image or visual inspection by the user. Therefore, the burden on the user can be reduced and the image inspection and dummy inspection can be performed using a simple method.

Also, in the above inspection method, image data is read out from the recording unit 63 in a dummy inspection performed before execution of a print job, stored in the system memory 65 or GPU memory 67, and then stored in the cache memory of the GPU 66. The data is stored and processed by the GPU 66. Therefore, when data is stored from the GPU memory 67 to the cache memory of the GPU 66, the test image data is stored faster than the correct image during the dummy test. Therefore, in image inspection after execution of a print job, the time required for image processing by the GPU 66 can be shortened. Therefore, the time required for the first image inspection can be shortened. As a result, the processing time for the first image inspection can be shortened without installing a CPU or GPU capable of faster processing.

Note that the present invention is not limited to the configuration described in the above-described embodiments, and various modifications and changes can be made without departing from the configuration of the present invention.

1 Image forming system, 10 Paper feeding device, 11 Paper feeding tray, 12, 41, 58 Conveyance section, 20 Inkjet recording device, 21 Image forming drum, 22 Transfer unit, 23 Recording material heating section, 24 Head unit, 25 Irradiation section , 26 delivery section, 30 image inspection device, 40 inspection section, 42 reversing conveyance path, 43 reversing section, 44 reading section, 45 paper discharge tray, 50 control section, 51, 64 CPU, 52 RAM, 53 ROM, 54 storage section , 55 image processing section, 56 operation display section, 57 input/output interface, 59 bus, 61 frame grabber, 62 chipset, 63 recording section, 65 system memory, 66 GPU, 67 GPU memory, 100 external device, 121,261 roller , 123,263 belt, 200 image forming section, 221 swing arm section, 222,264 transfer drum, 241 head control section, 242 head drive section, 581 conveyance drive section, 582 rotary encoder

Claims (7)

a reading unit that reads images printed on recording material;
a first processor, a second processor with higher image processing ability than the first processor, a first memory used by the first processor, and a second memory used by the second processor. The first processor and the second processor cooperate to generate image data of a test image obtained by reading an image printed on the recording material with the reading unit, and an image of a correct image. an inspection unit that performs an image inspection to extract defects in the inspection image by comparing the data with the inspection image;
Before executing the image inspection, the inspection unit executes a dummy inspection that compares image data of the correct images,
In the dummy test,
The first processor reads image data of the correct image into an arbitrary area of the first memory,
The second processor reads at least a part of the image data of the correct image into the second memory, and then stores it in a cache memory.
Image inspection equipment. The inspection unit erases the image data stored in the cache memory of the second processor after the image inspection is completed.
The image inspection device according to claim 1 . The inspection unit acquires, as the correct image, a read image of the printed matter output before executing the dummy inspection and inspected by the user through the reading unit.
The image inspection apparatus according to claim 1 or 2 . Before executing the dummy inspection, the inspection unit may perform color conversion, in which a raster image obtained by raster processing the image printed on the recording material is color-converted into color components similar to those of the inspection image. Get the raster image as the correct image
The image inspection apparatus according to claim 1 or 2 . An image forming system including an image forming device and an image inspection device,
a reading unit that reads images printed on recording material;
a first processor, a second processor with higher image processing ability than the first processor, a first memory used by the first processor, and a second memory used by the second processor. The first processor and the second processor cooperate to generate image data of a test image obtained by reading an image printed on the recording material with the reading unit, and an image of a correct image. an inspection unit that performs an image inspection to extract defects in the inspection image by comparing the data with the inspection image;
Before executing the image inspection, the inspection unit executes a dummy inspection that compares image data of the correct images,
In the dummy test,
The first processor reads image data of the correct image into an arbitrary area of the first memory,
The second processor reads at least a part of the image data of the correct image into the second memory, and then stores it in a cache memory.
Image forming system. During the dummy inspection by the image inspection device, the image forming device stops image formation.
The image forming system according to claim 5 . The image forming apparatus generates a color-converted raster image by color-converting the raster image into color components similar to those of the inspection image;
The image inspection device acquires the color-converted raster image as a correct image.
The image forming system according to claim 5 or 6 .

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