JP4650628B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method for inspecting an image state.

  The image formed on the recording medium is read by the image forming apparatus, and it is determined whether or not the formed image has a defect. If the defect has occurred, the image forming apparatus is configured so that the defect is removed. It is known to reset the recording conditions (Patent Document 1).

JP-A-11-109807

  However, if all the image data obtained by reading the image formed on the recording medium is stored, there is a problem that the memory capacity necessary for storing the image data increases. In the above conventional example, there is no disclosure about reducing the memory capacity necessary for storing image data obtained by reading an image.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus and an image forming method capable of inspecting an image state by efficiently using a memory.

  In order to achieve the above object, the first feature of the present invention is that output means for outputting an image, inspection condition acquisition means for acquiring an inspection condition for the state of an output image of the output means, and the output means The image forming apparatus includes a reading unit that reads an image output from the storage unit, and a storage unit that stores image data based on the image read by the reading unit according to the inspection condition acquired by the inspection condition acquisition unit. That is, since the amount of image data stored in the storage unit is switched according to the inspection condition acquired by the inspection condition acquisition unit, the state of the image can be inspected using the storage unit efficiently.

  The second feature of the present invention is that output means for outputting an image, inspection condition acquisition means for acquiring an inspection condition for the state of the output image of the output means, and an image output by the output means. A reading unit that reads, a storage unit that stores image data based on an image read by the reading unit in accordance with the inspection condition acquired by the inspection condition acquisition unit, and the image data stored by the storage unit based on the image data The image forming apparatus includes a correction unit that corrects an image output by the output unit. That is, since the amount of image data stored in the storage means can be switched according to the inspection conditions acquired by the inspection condition acquisition means, the storage means can be used efficiently to check the state of the image and correct the image. Can do.

  Preferably, the inspection condition acquisition unit acquires a condition for inspecting in-plane unevenness or streaks generated in an image output by the output unit.

  Preferably, the inspection condition acquisition unit acquires an inspection condition limited by at least one of the number of colors, the resolution, the limited range, and the number of bits of the image data. Therefore, the storage capacity required for the storage means to store the image data can be reduced, and the state of the image can be inspected using the storage means efficiently.

  The third feature of the present invention is that the image is output, the inspection condition for the state of the output image is acquired, the output image is read, and the read image is based on the acquired inspection condition. An image forming method for storing image data.

  The fourth feature of the present invention is that an image is output, an inspection condition for the state of the output image is acquired, the output image is read, and the read image is based on the acquired inspection condition. The image forming method stores image data and corrects the image based on the stored image data.

  According to the present invention, the state of an image can be inspected by efficiently using a memory.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes a user interface (UI) unit 11, a control unit 12, an exposure device 13, a plurality of image forming units 14, an intermediate transfer belt 16, recording medium trays 17 a to 17 d, a recording medium conveyance path 18, and a fixing device 19. And a DFE (Digital Front End) such as a computer or a server (not shown) from C (cyan), M (magenta), Y (yellow), and K (black) according to a user operation. Image data is acquired and an image is printed on a recording medium such as paper. The image forming apparatus 10 may include a computer and other terminal devices connected via a network as a system, and the UI unit 11 and the control unit 12 are arranged in any of the systems.

  An exposure device 13 is disposed above the image forming apparatus 10. The exposure apparatus 13 includes a light source, a lens, and the like (not shown), and a plurality of image forming units arranged below the exposure apparatus 13 with laser light modulated for each YMCK color according to image data input from the control unit 12. 14 respectively.

  The plurality of image forming units 14 are arranged corresponding to the colors constituting the color image. In this example, the first image forming unit 14Y, the second image forming unit 14M, and the third image forming corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K). The unit 14C and the fourth image forming unit 14K are horizontally arranged along the intermediate transfer belt 16 with a certain interval. The intermediate transfer belt 16 rotates as an intermediate transfer member in the direction of arrow a in the figure. The four image forming units 14Y, 14M, 14C, and 14K sequentially form toner images of the respective colors based on the image data input from the control unit 12, and the intermediate transfer belt 16 so that the plurality of toner images are superimposed on each other. The toner image is transferred to (primary transfer). The order of the colors of the image forming units 14Y, 14M, 14C, and 14K is not limited and is arbitrary.

  The recording medium conveyance path 18 is disposed below the intermediate transfer belt 16. The recording medium supplied from any of the recording medium trays 17a to 17d is conveyed on the recording medium conveying path 18, and the toner images of each color transferred onto the intermediate transfer belt 16 are collectively transferred (secondary transfer). The transferred toner image is fixed by the fixing device 19, the image is read by the image reading unit 20, and is discharged in the direction of the arrow b.

Next, the configuration of the image forming apparatus 10 will be described in detail.
The UI unit 11 is a user interface for the image forming apparatus 10, which is a touch panel, for example, and outputs a user instruction to the control unit 12.

  The first image forming unit 14Y, the second image forming unit 14M, the third image forming unit 14C, and the fourth image forming unit 14K are arranged and formed in parallel at a certain interval in the horizontal direction. The configuration is almost the same except that the color of the image is different. Accordingly, the first image forming unit 14Y will be described below. The configuration of each image forming unit 14 is distinguished by attaching Y, M, C, or K.

The image forming unit 14Y includes an optical scanning device 140Y and an image forming device 150Y.
The optical scanning device 140Y deflects and scans the laser beam corresponding to yellow (Y) input from the exposure device 13 with the rotary polygon mirror 142Y, and irradiates the photosensitive drum 152Y of the image forming device 150Y via the reflection mirror 144Y. To do.
The image forming apparatus 150Y includes a photosensitive drum 152Y as an image carrier that rotates at a predetermined rotation speed in the direction of arrow a, a charger 154Y that uniformly charges the surface of the photosensitive drum 152Y, and a photosensitive drum. The developing unit 156Y that develops the electrostatic latent image formed on the body drum 152Y, a cleaning device 158Y, and a charge removal device 159Y are included. The photosensitive drum 152Y is uniformly charged by the charger 154Y, and an electrostatic latent image is formed by the laser light irradiated by the optical scanning device 140Y. The electrostatic latent image formed on the photosensitive drum 152Y is developed with yellow toner by the developing unit 156Y and transferred to the intermediate transfer belt 16. After the toner image transfer process, residual toner and paper dust attached to the photoreceptor drum 152Y are removed by the cleaning device 158Y, and the photoreceptor drum 152Y is discharged by the charge removal device 159Y.
The other image forming units 14M, 14C and 14K also form magenta (M), cyan (C) and black (K) toner images in the same manner as described above, and intermediately transfer the formed toner images of the respective colors. Transfer to belt 16.

The intermediate transfer belt 16 is wound around the drive roll 160, the idle roll 162, the steering roll 164, and the backup roll 166 with a constant tension. The drive roll 160 is driven by a drive motor (not shown). By being rotationally driven, it is circulated at a predetermined speed in the direction of arrow a. The intermediate transfer belt 16 is formed into an endless belt by, for example, forming a flexible synthetic resin film such as polyimide in a belt shape and connecting both ends of the synthetic resin film formed in a belt shape by welding or the like. It has been done.
Further, the intermediate transfer belt 16 has a first primary transfer roll 168Y, a second primary transfer roll 168M, a third primary transfer roll 168C, and a position facing the image forming units 14Y, 14M, 14C, and 14K, respectively. A fourth primary transfer roll 168K is disposed, and the toner images of the respective colors formed on the photosensitive drums 152Y, 152M, 152C, and 152K are transferred onto the intermediate transfer belt 16 in a multiple manner by these primary transfer rolls 168. The

In the recording medium conveyance path 18, a paper feed roller 180 for taking out the recording medium from each of the recording medium trays 17a to 17d, a pair of recording medium conveyance rollers 182 and the recording medium are conveyed to a secondary transfer position at a predetermined timing. A resist roll 184 is provided.
A secondary transfer roll 186 that is in pressure contact with the backup roll 166 is disposed at the secondary transfer position on the recording medium conveyance path 18, and the toner images of the respective colors that are transferred onto the intermediate transfer belt 16 in a multiple manner. The secondary transfer roll 186 is secondarily transferred onto the recording medium by the pressing force and electrostatic force. The recording medium on which the toner image of each color is transferred is conveyed to the fixing device 19.
The fixing device 19 fixes the toner to the recording medium by applying heat and pressure to the recording medium on which the toner images of the respective colors are transferred.

  The image reading unit 20 is, for example, a contact-type image sensor that separates and reads an image into R (red), G (green), and B (blue-purple), reads a test image printed by the image forming apparatus 10, and performs a test image. Are output to the control unit 12. The image reading unit 20 may be a reading head including a reduction optical system.

  The control unit 12 includes a CPU 120, an image signal conversion unit 122, a test image data generation circuit 124, and a selector 126, and each color of CMYK acquired from the DFE according to a user instruction input via the UI unit 11. The image data is processed and output to the exposure device 13 and each part of the image forming apparatus 10 is controlled.

The CPU 120 controls each part constituting the image forming apparatus 10. Further, the CPU 120 acquires, for example, RGB image data read by the image reading unit 20 from the image signal conversion unit 122 in response to a user instruction input via the UI unit 11, for example, in-plane unevenness of the image or the like. A correction table (correction parameter) for detecting a streak, calculating a correction amount for correcting the density of each color of CMYK so that no in-plane unevenness or streak occurs in the image, and correcting the in-plane unevenness or streak from the calculated correction amount. ) And output to the image signal converter 122.
Note that the CMY density values corresponding to the RGB density values are set in advance.

The image signal conversion unit 122 includes a storage unit 128 including, for example, a FIFO and a non-volatile memory. The image signal conversion unit 122 acquires image data of CMYK colors from a DFE such as a computer or a server (not shown) under the control of the CPU 120 and receives the image data from the CPU 120. The density of the image data is converted in accordance with the correction parameter for each color and output to the selector 126. The image signal conversion unit 122 stores the image data read by the image reading unit 20 in accordance with an instruction (mode switching instruction) input from the CPU 120, and outputs the stored image data in response to an access from the CPU 120. To do.
Note that the storage unit 128 is also used for storing correction parameters received by the image signal conversion unit 122 from the CPU 120 and storing image data received from the image reading unit 20.

  FIG. 2 is a table showing combinations of mode switching instructions output from the CPU 120 to the storage unit 128. As a mode in which the CPU 120 instructs switching (correction mode), image correction conditions that limit the number of colors, resolution, stored image range, and number of bits (number of gradations) of image data to be stored in the storage unit 128 are combined. An in-plane unevenness correction mode and a streak correction mode are provided. When the CPU 120 outputs a mode switching instruction indicating the in-plane unevenness correction mode to the storage unit 128, the storage unit 128 has three colors (RGB) and a resolution of 100 dpi with resolution conversion. Store image data. When the CPU 120 outputs a mode switching instruction indicating the streak correction mode to the storage unit 128, the storage unit 128 has one color (any one of RGB), and the resolution is converted with resolution conversion. The image data of 200 dpi is stored. Furthermore, in both the in-plane unevenness correction mode and the streak correction mode, the storage conditions (limited range) for the image and the correction conditions that limit the number of bits can be combined.

The test image data generation circuit 124 (FIG. 1) generates test image data for forming a test image for each color of CMYK and outputs the test image data to the selector 126.
FIG. 3 is a diagram showing a pattern of a test image formed by the image forming unit 14 in accordance with the test image data generated by the test image data generation circuit 124. FIG. 3A shows any one of CMYK or tertiary colors. (B) is a second pattern in which YMCs are arranged in order. As shown in FIG. 3, in both the first pattern and the second pattern, the test image has a uniform density in the main scanning direction, and a plurality of regions having different densities from the low density in the sub-scanning direction. They are arranged in order of high density. The test image may be an image in which the density is set uniformly in the sub-scanning direction and a plurality of regions having different densities are arranged in order from the low density to the high density in the main scanning direction.

  The selector 126 (FIG. 1) corrects a mode in which the image forming apparatus 10 prints an image according to the CMYK color image data acquired from the DFE (normal print mode) or in-plane unevenness or streaks of the printed image. A setting indicating in which mode (test mode) to operate is acquired via the UI unit 11 or the like, and image data selected according to the acquired setting is output to the exposure apparatus 13. . That is, the selector 126 selects and outputs the image data input from the image signal converter 122 when acquiring the setting that should operate in the normal printing mode, and acquires the setting that should operate in the test mode. The test image data input from the test image data generation circuit 124 is selected and output.

Next, processing for generating correction parameters by the image forming apparatus 10 in order to correct in-plane unevenness or streaks of the image will be described in detail.
FIG. 4 is a conceptual diagram illustrating processing in which the image forming apparatus 10 generates correction parameters in order to correct in-plane unevenness or streaks of an image.
FIG. 5 is a flowchart illustrating a process (S10) in which the image forming apparatus 10 generates correction parameters in order to correct in-plane unevenness or streaks of an image.
As shown in FIG. 4, in step 100 (S <b> 100), the CPU 120 acquires an instruction indicating a correction mode corresponding to a correction condition for image density via the UI unit 11.

  In step 102 (S102), the CPU 120 instructs the selector 126, the image forming unit 14, and the like to output a test image.

  In step 104 (S104), the image forming unit 14 outputs a test image.

  In step 106 (S106), the image reading unit 20 reads the test image and outputs RGB image data obtained by disassembling the test image to the storage unit 128.

  In step 108 (S108), the storage unit 128 stores the RGB image data output from the image reading unit 20 in a limited manner according to the mode switching instruction output from the CPU 120.

  In step 110 (S110), the CPU 120 acquires the image data stored in the storage unit 128, and inspects the acquired image data according to the correction mode (detects in-plane unevenness or streaks).

  In step 112 (S112), the CPU 120 generates a correction parameter for correcting the detected in-plane unevenness or streaks.

  In step 114 (S114), the storage unit 128 stores the correction parameter generated by the CPU 120.

  As described above, since the CPU 120 switches the correction condition for limiting the image data to be stored in the storage unit 128 according to the mode switching instruction, the storage capacity of the storage unit 128 can be efficiently used according to the purpose of image correction. .

1 is a side view illustrating an outline of an image forming apparatus according to an embodiment of the present invention. It is a graph which shows the combination of the mode switching instruction | indication which CPU outputs with respect to a memory | storage part. It is a figure which shows the pattern of the test image which an image formation unit forms according to the test image data which the test image data generation circuit produced | generated, Comprising: (A) is any one color of CMY, or a tertiary color (gray which consists of CMY etc.) ) And (B) is a second pattern in which YMCs are arranged in order. FIG. 6 is a conceptual diagram illustrating processing in which an image forming apparatus generates correction parameters in order to correct in-plane unevenness or streaks of an image. 10 is a flowchart illustrating processing (S10) in which the image forming apparatus generates correction parameters in order to correct in-plane unevenness or streaks of an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 UI part 12 Control part 120 CPU
122 image signal conversion unit 124 test image data generation circuit 126 selector 128 storage unit 13 exposure device 14Y first image forming unit 14M second image forming unit 14C third image forming unit 14K fourth image forming unit 16 intermediate Transfer belts 17a to 17d Recording medium tray 18 Recording medium conveyance path 19 Fixing device 20 Image reading unit

Claims (4)

An output means for outputting an image;
Inspection conditions for acquiring inspection conditions limited by at least one of the number of colors, resolution, limited range, and number of bits of image data for inspecting in-plane unevenness or streaks occurring in the image output by the output means Acquisition means;
Reading means for reading an image output by the output means;
Number of colors of the image data based on the image in which the reading unit has read, the resolution, the limited range and the number of bits at least one, is limited to a predetermined value in accordance with the inspection conditions in which the test condition acquiring means acquires An image forming apparatus having storage means for storing. Based on the image data to which the storage means stores, correction means for correcting an image in which the output means outputs
The image forming apparatus according to claim 1, further comprising: Output an image,
Obtain inspection conditions limited by at least one of the number of colors, resolution, limited range and number of bits of image data for inspecting in-plane unevenness or streaks that occur in the output image ,
Read the output image,
An image forming method for storing at least one of the number of colors, the resolution, the limited range, and the number of bits of image data based on a read image , limited to a predetermined value according to an acquired inspection condition . Correct images based on stored image data
The image forming method according to claim 3 .

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