JP2019201280A - Inspection device, image reading device, image forming apparatus, calculation method, and program - Google Patents

Abstract

To accurately execute gray balance adjustment of image reading means in a reduced space.SOLUTION: An inspection device comprises: an achromatic color reference member that has a uniform gray patch having a constant density in a main scanning direction; a movable body that holds the achromatic color reference member in an advanceable/retreatable manner with respect to a reading position opposite to image reading means; movable body control means that controls a movement of the movable body during gray balance adjustment to move the achromatic color reference member to the reading position; reading control means that reads the achromatic color reference member with the image reading means during the gray balance adjustment; and calculation means that calculates a gray balance adjustment coefficient of the image reading means so that each of the RGB colors becomes a target value according to a result of reading performed by the reading control means.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an inspection apparatus, an image reading apparatus, an image forming apparatus, a calculation method, and a program.

  In an image reading apparatus, the spectral sensitivity of a reading sensor (CCD or CIS) that is an image reading means, the spectral sensitivity of an infrared cut filter for removing infrared light components, and the spectral characteristics of a light source (LED) are reduced. Variations occur. Due to these variations, read data obtained by reading the same color document may be different for each image reading apparatus.

  Therefore, in order to correct the above-described various variations, a reference original on which a uniform pattern of achromatic colors is printed is read, and level correction (hereinafter, gray balance adjustment) is performed for each color so that each color of RGB becomes a target value. It is known.

  Patent Document 1 includes a black subtraction value correction unit that adds and subtracts the black subtraction value subtracted by the black subtraction unit, and adjusts the gray balance even in a portion having a small reflectance, thereby achieving a gray balance in a wider reflectance range. A technique capable of maintaining the above is disclosed.

  In a conventional gray balance adjustment method, a reference document formed by an image forming apparatus is read by an image reading unit to be adjusted. In other words, the image reading unit to be adjusted needs to read a reference document formed through a conveyance path such as transfer and fixing. Therefore, the conventional gray balance adjustment method has a problem that it is difficult to perform the gray balance adjustment with high accuracy because the reference original is contaminated with toner or the like and is damaged due to conveyance, thereby causing a reading error.

  The present invention has been made in view of the above, and an object of the present invention is to accurately adjust the gray balance of an image reading unit in a small space.

  In order to solve the above-described problems and achieve the object, the present invention provides an achromatic reference member having a uniform gray patch having a constant density in the main scanning direction, and the achromatic reference member facing the image reading unit. A movable body that can be moved forward and backward with respect to the reading position to be moved, a movable body control unit that controls the operation of the movable body to adjust the gray balance adjustment, and moves the achromatic reference member to the reading position; A read control means for reading the achromatic color reference member by the image reading means at the time of adjustment, and a gray balance adjustment coefficient of the image reading means so as to be a target value for each color of RGB according to a reading result by the read control means And calculating means for calculating.

  According to the present invention, there is an effect that the gray balance adjustment of the image reading unit can be performed with a small amount of space and with high accuracy.

FIG. 1 is a schematic diagram illustrating an example of a hardware configuration of a printing system according to the embodiment. FIG. 2 is a schematic diagram illustrating an installation mode of the reading device and the reference member. FIG. 3 is a perspective view showing an achromatic color reference plate provided on the rotating member. FIG. 4 is a plan view exemplarily showing an achromatic color pattern of the achromatic color reference plate. FIG. 5 is a block diagram illustrating an example of electrical connection of hardware of the printing system. FIG. 6 is a block diagram illustrating an example of electrical connection of hardware related to the inspection apparatus. FIG. 7 is a functional block diagram illustrating a functional configuration of the printing system. FIG. 8 is a diagram illustrating the relationship between the reading device, the achromatic color reference plate, and the recording medium. FIG. 9 is a timing chart showing the timing of the achromatic color reference plate reading operation during gray balance adjustment. FIG. 10 is a flowchart schematically showing the flow of the gray balance adjustment process. FIG. 11 is a diagram illustrating a rotating operation of the rotating member in the gray balance adjustment process. FIG. 12 is a diagram illustrating a modification of the reference member.

  Hereinafter, embodiments of an inspection apparatus, an image reading apparatus, an image forming apparatus, a calculation method, and a program will be described in detail with reference to the accompanying drawings. Hereinafter, an example in which the inspection apparatus, the image reading apparatus, and the image forming apparatus are applied to a printing system including a printing apparatus such as a commercial printing machine (production printing machine) that continuously prints a large number of sheets in a short time will be described. However, the present invention is not limited to this.

  FIG. 1 is a schematic diagram illustrating an example of a hardware configuration of a printing system 1 according to the embodiment. As illustrated in FIG. 1, a printing system 1 that is an image forming apparatus includes a printing apparatus 100, an inspection apparatus 200, and a stacker 300.

  The printing apparatus 100 includes an operation panel 101, tandem electrophotographic image forming units 103Y, 103M, 103C, and 103K, a transfer belt 105, a secondary transfer roller 107, a paper feeding unit 109, and a pair of conveying rollers. 102, a fixing roller 104, and a reverse path 106.

  The operation panel 101 is an operation display unit that performs various operation inputs to the printing apparatus 100 and the inspection apparatus 200 and displays various screens.

  Each of the image forming units 103Y, 103M, 103C, and 103K forms a toner image by performing an image forming process (charging process, exposure process, development process, transfer process, and cleaning process), and the formed toner image Is transferred to the transfer belt 105. In this embodiment, a yellow toner image is formed on the image forming unit 103Y, a magenta toner image is formed on the image forming unit 103M, a cyan toner image is formed on the image forming unit 103C, and the image forming unit 103K However, the present invention is not limited to this.

  The transfer belt 105 conveys the toner image (full color toner image) transferred from the image forming units 103Y, 103M, 103C, and 103K to the secondary transfer position of the secondary transfer roller 107. In this embodiment, a yellow toner image is first transferred to the transfer belt 105, and then a magenta toner image, a cyan toner image, and a black toner image are sequentially superimposed and transferred. It is not limited.

  The paper feeding unit 109 accommodates a plurality of recording media that are objects to be processed (conveyed objects) in an overlapping manner, and feeds the recording media. Examples of the recording medium include, but are not limited to, recording paper (transfer paper). For example, images such as coated paper, cardboard, OHP (Overhead Projector) sheet, plastic film, and copper foil can be recorded. Any medium may be used. In the present embodiment, the recording medium on which an image is formed is a processing target (conveyed object), but the present invention is not limited to this, and a sheet that is not a target for forming an image such as a prepreg is a processing target ( (Conveyed object).

  The transport roller pair 102 transports the recording medium fed by the paper feed unit 109 in the direction of arrow s on the transport path a.

  The secondary transfer roller 107 collectively transfers the full-color toner image conveyed by the transfer belt 105 onto the recording medium conveyed by the conveyance roller pair 102 at the secondary transfer position.

  The fixing roller 104 fixes the full-color toner image on the recording medium by heating and pressurizing the recording medium on which the full-color toner image is transferred.

  In the case of single-sided printing, the printing apparatus 100 sends a printed matter that is a recording medium on which a full-color toner image is fixed to the inspection apparatus 200. On the other hand, in the case of duplex printing, the printing apparatus 100 sends the recording medium on which the full-color toner image is fixed to the reverse path 106.

  The reverse path 106 reverses the front and back surfaces of the recording medium by switching back the sent recording medium and conveys it in the direction of the arrow t. The recording medium transported by the reverse path 106 is transported again by the transport roller pair 102, the full-color toner image is transferred to the surface opposite to the previous time by the secondary transfer roller 107, fixed by the fixing roller 104, and printed. And sent to the inspection apparatus 200 and the stacker 300.

  The inspection apparatus 200 located downstream of the printing apparatus 100 also functions as an image reading apparatus, and includes a reading device 201 dedicated to inspection and a reference member 202.

  The reading device 201 can be realized by, for example, a CIS (Contact Image Sensor) in which a plurality of imaging elements (CMOS image sensors) are arranged in a line. The reading device 201 receives reflected light from a reading target and outputs an image signal. Specifically, the reading device 201 sets the reference member 202 as a reading target.

  The CIS applied to the reading device 201 is generally known to have a configuration that ensures a necessary effective reading length in the main scanning direction by arranging a plurality of sensor chips having a plurality of pixels in the main scanning direction.

  The reference member 202 is used for gray balance adjustment. Gray balance adjustment includes variations in spectral sensitivity of the line sensor (CIS) in the reading device 201, variations in spectral sensitivity of the infrared cut filter for removing infrared light components, variations in spectral characteristics of the light source (LED), and the like. For correction, a uniform pattern of achromatic colors is read, and level correction is performed for each color so that each color of RGB becomes a target value.

  Further, the reading device 201 sets the conveyance position of the recording medium sent from the printing apparatus 100 and the processing position (printing position) for the recording medium as the reading target. That is, the printing system 1 arranges an inspection apparatus 200 having a reading device 201 dedicated for inspection at the subsequent stage of the printing apparatus 100, thereby performing image reading on the recording medium output from the printing apparatus 100, color calibration, Position detection or the like can also be performed.

  The inspection apparatus 200 discharges the recording medium to the stacker 300.

  The stacker 300 includes a tray 301. The stacker 300 stacks the recording medium discharged by the inspection apparatus 200 on the tray 301.

  Next, the reading device 201 and the reference member 202 in the inspection apparatus 200 will be described.

  FIG. 2 is a schematic diagram illustrating how the reading device 201 and the reference member 202 are installed. As shown in FIG. 2, the reference member 202 includes a rotating member 203 that is a moving body. The rotating member 203 is a rotating body that can rotate around a shaft 203 a and is driven to rotate by a motor 204. On the surface of the rotating member 203, an achromatic reference plate 205, which is an achromatic reference member, and a white reference plate 206, which is a white reference member, are installed.

  Here, FIG. 3 is a perspective view showing the achromatic reference plate 205 provided on the rotating member 203. As shown in FIG. 3, the achromatic color reference plate 205 is a flat plate having a flat surface, and a print sheet on which an achromatic color pattern having a constant density is printed in the main scanning direction.

  Here, FIG. 4 is a plan view illustrating an achromatic color pattern of the achromatic color reference plate 205 as an example. As shown in FIG. 4, the achromatic color pattern of the achromatic color reference plate 205 is a uniform gray patch having a constant density in the main scanning direction. As shown in FIG. 4, the detection of the achromatic pattern is performed in a plurality of areas divided in the main scanning direction. In FIG. 4, the achromatic pattern is divided into 16 areas, but there is no problem with other division numbers.

  The achromatic color reference plate 205 may be a plate in which an achromatic color pattern is applied on a plane. The reason why the print sheet is not directly attached to the surface of the rotating member 203 with an adhesive or a double-sided tape is that there is a concern that the print sheet may peel off from the end portion over time.

  The achromatic color reference plate 205 is used for gray balance adjustment. The white reference plate 206 is used for shading correction and light amount adjustment for correcting optical main scanning unevenness.

  The achromatic color reference plate 205 and the white color reference plate 206 are arranged on the facing surface of the reading device 201 at a predetermined timing as the rotation member 203 rotates. That is, the rotating member 203 holds the achromatic color reference plate 205 and the white color reference plate 206 so as to be movable forward and backward with respect to the reading position facing the reading device 201.

  According to such an inspection apparatus 200, by installing the achromatic color reference plate 205 inside the inspection apparatus 200, it is not necessary to convey the reference document for gray balance adjustment, and the gray balance adjustment can be performed with high accuracy. It becomes possible.

  Further, according to the inspection apparatus 200, by installing the achromatic color reference plate 205 and the white color reference plate 206 on the rotating member 203, it is possible to perform shading correction and gray balance adjustment with high accuracy in a small space.

  FIG. 5 is a block diagram illustrating an example of electrical connection of hardware of the printing system 1.

  As shown in FIG. 5, the printing system 1 has a configuration in which a controller 10, an engine unit (Engine) 60, an engine unit (Engine) 70, and a motor drive unit 80 are connected by a PCI bus. The controller 10 is a controller that controls the entire printing system 1, drawing, communication, and input from the operation panel 101 that is an operation display unit.

  The engine unit 60 is an engine that can be connected to the PCI bus, and is, for example, a scanner engine such as the reading device 201. The engine unit 60 includes an image processing part such as error diffusion and gamma conversion in addition to the engine part.

  The engine unit 70 is an engine that can be connected to the PCI bus, and is, for example, a print engine such as a plotter including the image forming units 103Y, 103M, 103C, and 103K.

  The motor driving unit 80 connects the motor 204.

  The controller 10 includes a central processing unit (CPU) 11, a north bridge (NB) 13, a system memory (MEM-P) 12, a south bridge (SB) 14, a local memory (MEM-C) 17, and an ASIC. (Application Specific Integrated Circuit) 16 and a hard disk drive (HDD) 18, and the North Bridge (NB) 13 and the ASIC 16 are connected by an AGP (Accelerated Graphics Port) bus 15. The MEM-P 12 further includes a ROM 12a and a RAM 12b.

  The CPU 11 performs overall control of the printing system 1 and has a chip set including the NB 13, the MEM-P 12, and the SB 14, and is connected to other devices via the chip set.

  The NB 13 is a bridge for connecting the CPU 11 to the MEM-P 12, SB 14, and the AGP bus 15, and includes a memory controller that controls reading / writing with respect to the MEM-P 12, a PCI master, and an AGP target.

  The MEM-P 12 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a memory for drawing a printer, and the like, and includes a ROM 12a and a RAM 12b. The ROM 12a is a read-only memory used as a program / data storage memory, and the RAM 12b is a writable / readable memory used as a program / data development memory, a printer drawing memory, or the like.

  The SB 14 is a bridge for connecting the NB 13 to a PCI device and peripheral devices. The SB 14 is connected to the NB 13 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The ASIC 16 is an IC (Integrated Circuit) for image processing having hardware elements for image processing, and has a role of a bridge for connecting the AGP bus 15, the PCI bus, the HDD 18, and the MEM-C 17. The ASIC 16 includes a PCI target and an AGP master, an arbiter (ARB) that is the core of the ASIC 16, a memory controller that controls the MEM-C 17, and a plurality of DMACs (Direct Memory) that perform rotation of image data by hardware logic. Access Controller) and a PCI unit that performs data transfer between the engine unit 60 and the engine unit 70 via the PCI bus. The ASIC 16 is connected with a USB 40 and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface (I / F) 50 via a PCI bus. The operation panel 101 is directly connected to the ASIC 16.

  The MEM-C 17 is a local memory used as a copy image buffer and a code buffer, and the HDD 18 is a storage for storing image data, programs, font data, and forms.

  The AGP bus 15 is a bus interface for a graphics accelerator card proposed for speeding up graphics processing. The AGP bus 15 speeds up the graphics accelerator card by directly accessing the MEM-P 12 with high throughput. It is.

  A program executed in the printing system 1 according to the present embodiment is a file in an installable format or an executable format, and is a computer such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk). The information may be provided by being recorded on a recording medium that can be read by the user.

  Furthermore, the program executed in the printing system 1 of the present embodiment may be configured to be stored by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the program executed by the printing system 1 of the present embodiment may be configured to be provided or distributed via a network such as the Internet.

  FIG. 6 is a block diagram illustrating an example of electrical connection of hardware related to the inspection apparatus 200. As shown in FIG. 6, the reading device 201 receives a light source 201 a that irradiates light to the reference member 202 and the processing target (conveyed object), and reflected light from the reference member 202 and the processing target (conveyed object). A reading sensor (image sensor) 201b that is an image reading unit, a signal processing unit 201c that performs A / D conversion or the like on image signals (R, G, B) output from the image sensor 201b, and a light source 201a A control unit 201d that controls the image sensor 201b and the signal processing unit 201c.

  The signal processing unit 201c performs shading correction and the like on the image signals (R, G, B) output from the image sensor 201b.

  As shown in FIG. 6, the CPU 11 controls the reading device 201 and the motor driving unit 80 via the PCI bus. More specifically, the reading device 201 starts and stops acquisition of image data in response to an imaging command from the CPU 11. The motor drive unit 80 receives a motor drive command from the CPU 11 and outputs a motor pulse. The motor drive unit 80 includes a circuit that counts the output motor pulses, and can feed back the count value to the CPU 11 at an arbitrary timing.

  Next, functions that are exhibited when the CPU 11 of the printing system 1 executes a program stored in the HDD 18 or the ROM 12a will be described. Here, description of conventionally known functions is omitted, and characteristic functions exhibited by the printing system 1 of the present embodiment will be described in detail.

  FIG. 7 is a functional block diagram illustrating a functional configuration of the printing system 1.

  As illustrated in FIG. 7, the CPU 11 of the printing system 1 functions as a reading control unit 110 that is a reading control unit, a motor control unit 111 that is a moving body control unit, and a correction coefficient calculation unit 112 that is a calculation unit. In addition to the reading control unit 110, the motor control unit 111, and the correction coefficient calculation unit 112, the CPU 11 relatively moves a processing target (conveyed object) to be read by the reading device 201 in the sub-scanning direction. It goes without saying that functions such as a moving unit may be realized.

  In this embodiment, the characteristic functions exhibited by the printing system 1 are realized by the CPU 11 executing the program. However, the present invention is not limited to this. For example, the functions of the respective units described above are implemented. Some or all of them may be realized by a dedicated hardware circuit.

  The motor control unit 111 outputs a motor drive command to the motor drive unit 80 to drive the rotation member 203 to rotate. In addition, the motor control unit 111 outputs a motor drive stop command to the motor drive unit 80 to stop the rotation of the rotation member 203.

  More specifically, the motor control unit 111 controls the operation of the rotating member 203 during gray balance adjustment to rotate the achromatic reference plate 205 to the reading position facing the reading device 201, and then rotates the rotating member 203. Stop. As a result, variations in reading an achromatic pattern can be reduced, and gray balance adjustment can be performed with high accuracy.

  Here, FIG. 8 is a diagram showing the relationship between the reading device 201, the achromatic color reference plate 205, and the recording medium 211. As shown in FIG. 8A, the achromatic color reference plate 205 is rotationally controlled to a reading position facing the reading device 201 during gray balance adjustment. FIG. 8B shows the position of the rotating member 203 in the reading mode, and rotation control is performed so that the achromatic reference plate 205 and the white reference plate 206 do not face the reading device 201. The distance L between the reading device 201 and the achromatic color reference plate 205 at the time of gray balance adjustment is the same as the distance L between the reading device 201 and the recording medium 211 on the transport surface 210 in the reading mode shown in FIG. Become. As a result, since the reading conditions when reading the recording medium 211 and the achromatic color reference plate 205 are the same, reading can be performed with minimal influences such as illumination depth of the light source and depth of focus. Therefore, the gray balance adjustment can be performed with high accuracy.

  As shown in FIG. 8B, the achromatic color reference plate 205 and the white color reference plate 206 are rotationally controlled so as not to face the reading device 201 in the reading mode. This is to prevent the white reference plate 206 from being stained. As shown in FIG. 8B, in the reading mode, the reading device 201 detects color information and position information of the recording medium 211.

  The reading control unit 110 outputs an imaging command to the control unit 201 d of the reading device 201 and starts reading by the reading device 201. In addition, when the reading control unit 110 receives a reading signal from the reading device 201, the reading control unit 110 outputs an imaging end command to the control unit 201 d of the reading device 201 and ends reading by the reading device 201.

  More specifically, the reading control unit 110 waits for a time until the vibration of the rotating member 203 is stabilized after the rotation of the rotating member 203 by the motor control unit 111, and then reads the achromatic color reference plate 205 by the reading device 201. Start. As described above, since the achromatic color reference plate 205 is read after the vibration at the time of stopping of the rotating member 203 is settled, the gray balance adjustment can be performed with high accuracy.

  The correction coefficient calculation unit 112 calculates a gray balance correction coefficient so as to be a target value for each color of RGB in accordance with the reading result of the achromatic color reference plate 205.

  Here, FIG. 9 is a timing chart showing the timing of the reading operation of the achromatic color reference plate 205 at the time of gray balance adjustment. As shown in FIG. 9, first, a motor drive command for moving the rotating member 203 to a reading position where the achromatic reference plate 205 faces the reading device 201 is issued from the motor control unit 111 to the motor driving unit 80. The motor driving unit 80 that has received the signal starts outputting motor pulses.

  At this time, the motor driving unit 80 starts counting output pulses at the same time, and a pulse equivalent to the amount of movement from the initial position of the achromatic reference plate 205 to the reading position, that is, from the initial position of the white reference plate 206 to the reading start position. Is counted, and a count completion notification is fed back to the reading control unit 110.

  Upon receiving the count completion notification, the reading control unit 110 issues an imaging command after the motor vibration period (arrow A), and the control unit 201d of the reading device 201 that has received this starts reading an image.

  By the above operation, the achromatic color reference data can be acquired in a state where the achromatic color reference plate 205 is stopped and after the vibration is stopped.

  Next, gray balance adjustment processing executed by the printing system 1 will be described. The printing system 1 has an adjustment scan mode for performing gray balance adjustment in addition to a reading mode for normal document reading.

  Schematically, in the adjustment scan mode, the inspection apparatus 200 reads the achromatic color reference plate 205, calculates a gray balance correction coefficient so as to be a target value for each color of RGB, and performs level adjustment (gray balance adjustment). To do. The achromatic color reference plate 205 is previously measured with a colorimeter. Then, RGB target values are set from the measurement results. At the time of gray balance adjustment, the inspection apparatus 200 sets the gray balance correction coefficient for each RGB so that the set target value is obtained.

  The following formula (1) is a formula for calculating the gray balance correction coefficient. As shown in the following formula (1), the correction coefficient calculation unit 112 calculates a gray balance correction coefficient (Xref) for each RGB. The target value obtained from the colorimeter is different for each RGB. Normally, the reflectance of the gray patch of the achromatic color reference plate 205 is 40% to 60% in the vicinity of the halftone.

Xref_x = (255 / gb_tgt_x) × (D−B) / (W−B) (1)
Xref_x ... Gray balance correction coefficient (x: r / g / b)
gb_tgt_x ... Target value obtained from the colorimeter (x: r / g / b)
D: Gray patch reading value of the achromatic reference plate 205 W: Reading value of the white reference plate 206 B: Black subtraction value

  The correction coefficient calculation unit 112 calculates an average value of reading values for each area obtained by dividing the achromatic color reference plate 205 in the main scanning direction as shown in FIG. Calculate the average value of the area. Thereby, even if dust adheres to the achromatic color pattern (gray patch) of the achromatic color reference plate 205, it is possible to minimize a decrease in reading accuracy.

As a method of reflecting the gray balance correction coefficient, there is a method of inserting the gray balance correction coefficient into the shading calculation as shown in the following equation (2).
Dout (n) = (D−B) / ((W−B) × Xref_x) × 255 (2)

  As a result, the gray balance adjustment of the image sensor 201b of the inspection apparatus 200 is accurately performed in a space-saving manner.

  Next, the flow of gray balance adjustment processing will be described.

  FIG. 10 is a flowchart schematically showing the flow of the gray balance adjustment process, and FIG. 11 is a view showing the rotation operation of the rotating member 203 in the gray balance adjustment process.

  As shown in FIG. 10, when performing gray balance adjustment, the reading control unit 110 first acquires the black subtraction value of the image sensor 201b of the reading device 201 with the light source 201a of the reading device 201 turned off ( Step S101).

  Thereafter, the reading control unit 110 turns on the light source 201a of the reading device 201 (step S102).

  Thereafter, the reading control unit 110 waits for the light amount stabilization time of the light source 201a of the reading device 201 (step S103).

  On the other hand, the motor control unit 111 controls the motor driving unit 80 to execute homing to move the rotating member 203 to the home position (step S201).

  After performing the homing, the motor control unit 111 starts rotating the rotating member 203 so that the white reference plate 206 is positioned at the reading position facing the reading device 201 for the shading operation (step S202).

  Thereafter, the motor control unit 111 stops the rotation of the rotating member 203 when the white reference plate 206 is positioned at the reading position facing the reading device 201 (step S203). After stopping the rotating member 203, the motor control unit 111 waits until the vibration of the rotating member 203 is stabilized (step S204).

  As shown in FIG. 11A, the white reference plate 206 is positioned at a reading position facing the reading device 201 during shading correction and light amount adjustment.

  Waiting for the light amount stabilization time of the light source 201a of the reading device 201 (step S103) or waiting for the vibration stabilization time of the rotating member 203 (step S204), whichever is longer (in this embodiment, the rotating member 203) The reading control unit 110 controls the reading device 201 to read an image of the white reference plate 206 (step S104). Further, after the completion of the weighting and after reading the image of the white reference plate 206, the motor control unit 111 causes the achromatic color reference plate 205 to be positioned at a reading position facing the reading device 201 for the gray balance adjustment operation. Reverse rotation of the rotating member 203 is started (step S205).

  In this embodiment, the white reference plate 206 is read while the rotating member 203 is stopped. However, the white reference plate 206 is read while rotating the rotating member 203 in the reverse direction. You may make it do.

  Thereafter, the motor control unit 111 stops the rotation of the rotating member 203 when the achromatic color reference plate 205 is positioned at the reading position facing the reading device 201 (step S206). After stopping the rotating member 203, the motor control unit 111 waits until the vibration of the rotating member 203 is stabilized (step S207).

  As shown in FIG. 11B, the achromatic color reference plate 205 is positioned at a reading position facing the reading device 201 during gray balance adjustment.

  After waiting for the vibration stabilization time of the rotating member 203 (step S207), the reading control unit 110 controls the reading device 201 to execute image reading of the achromatic reference plate 205 (step S105).

  Thereafter, the motor control unit 111 controls the motor driving unit 80 to perform homing to move the rotating member 203 to the home position (step S208), and then stops the rotation of the rotating member 203 (step S209).

  On the other hand, the correction coefficient calculation unit 112 calculates the average value of the reading values for each area obtained by dividing the achromatic color reference plate 205 in the main scanning direction, and further calculates the average value of all the areas of the achromatic color reference plate 205 ( In step S106, a gray balance correction coefficient is calculated (step S107).

  The calculated gray balance correction coefficient is put into the shading calculation at the time of shading correction at the time of actual image reading. By performing the shading correction using the gray balance correction coefficient in this way, a gray-balanced read value is obtained.

  As described above, according to the present embodiment, the gray balance adjustment of the inspection apparatus 200 is performed by reading the achromatic color reference plate 205 having the gray patch installed on the rotating member 203, and thus the image sensor 201b of the inspection apparatus 200. The gray balance can be adjusted with high accuracy in a small space.

  In the present embodiment, the achromatic color reference plate 205 and the white color reference plate 206 are installed on the surface of the rotating member 203, but the present invention is not limited to this. Here, FIG. 12 is a view showing a modification of the reference member 202. As shown in FIG. 12, for example, the achromatic color reference plate 205 and the white color reference plate 206 are held by a plate-like member 207 that is a moving body, and the achromatic color reference plate 205 and the reading position facing the reading device 201. The white reference plate 206 may be moved in the direction of arrow B so as to freely advance and retract.

  In this embodiment, a CIS that is a so-called equal-magnification optical system is applied as the reading device 201. However, the present invention is not limited to this. For example, the reading device 201 may be a so-called reduction optical system reading device including a light source, a plurality of reflecting members (mirrors), an imaging lens, a linear image sensor (reading sensor), and the like. .

  In this embodiment, the inspection apparatus, the image reading apparatus, and the image forming apparatus according to the present invention are described as examples applied to a printing system including an electrophotographic printing apparatus. However, the present invention is not limited to this. The present invention can also be applied to a printing system including an inkjet printing apparatus.

  In the present embodiment, the inspection apparatus, the image reading apparatus, and the image forming apparatus according to the present invention have been described as examples applied to a printing system including a printing apparatus such as a commercial printing machine (production printing machine). The present invention is not limited to this, and any image forming apparatus such as a multifunction machine, a copier, a printer, a scanner device, and a facsimile machine having at least two functions among a copy function, a printer function, a scanner function, and a facsimile function. Can be applied.

  Furthermore, in the present embodiment, the inspection apparatus and the image reading apparatus according to the present invention have been described with reference to an example applied to the image forming field. However, the present invention is not limited to this, and various fields such as inspection in the FA field, for example. It can be applied to.

DESCRIPTION OF SYMBOLS 1 Reading apparatus, image forming apparatus 70 Print engine 110 Reading control means 111 Moving body control means 112 Calculation means 200 Inspection apparatus 201 Reading device 201b Image reading means 203,207 Moving body 205 Achromatic reference member 206 White reference member

JP 2005-295158 A

Claims (12)

An achromatic reference member having a uniform gray patch having a constant density in the main scanning direction;
A moving body that holds the achromatic reference member so as to be movable forward and backward with respect to a reading position facing the image reading means;
Moving body control means for controlling the operation of the moving body during gray balance adjustment and moving the achromatic color reference member to the reading position;
Reading control means for reading the achromatic reference member by the image reading means at the time of gray balance adjustment;
A calculation unit that calculates a gray balance adjustment coefficient of the image reading unit so as to be a target value for each color of RGB according to a reading result by the reading control unit;
An inspection apparatus comprising: A white reference member which is held by the movable body so as to be movable back and forth with respect to the reading position and is used for shading correction;
The moving body control means controls the operation of the moving body during shading correction, and moves the white reference member to the reading position.
The inspection apparatus according to claim 1. The moving body is a rotating body that rotates the achromatic reference member.
The inspection apparatus according to claim 1 or 2, wherein The moving body control means controls the operation of the moving body at the time of reading a processing target, and moves the achromatic color reference member and the white color reference member to a position that avoids the reading position.
The inspection apparatus according to claim 2. The achromatic reference member is a plane,
The moving body control means controls the operation of the rotating body during gray balance adjustment, rotates the achromatic color reference member to the reading position, and then stops the rotating body.
The inspection apparatus according to claim 3. The reading control means waits for a time until the rotating body is stabilized after the rotating body is stopped by the moving body control means, and starts reading the achromatic color reference member by the image reading means.
The inspection apparatus according to claim 5. The distance between the achromatic reference member and the image reading unit at the time of gray balance adjustment is the same as the distance between the image reading unit and the processing target at the time of reading the processing target.
The inspection apparatus according to any one of claims 1 to 6, wherein: The calculating means calculates an average value for each of a plurality of areas obtained by dividing the achromatic color reference member in the main scanning direction, calculates an average value of all the areas, and calculates the gray balance adjustment coefficient.
The inspection apparatus according to any one of claims 1 to 7, wherein A reading device having image reading means;
The inspection apparatus according to any one of claims 1 to 8, which performs gray balance adjustment of the image reading unit;
An image reading apparatus comprising: A print engine,
An image reading apparatus according to claim 9,
An image forming apparatus comprising: An inspection comprising: an achromatic reference member having a uniform gray patch having a constant density in the main scanning direction; and a moving body that holds the achromatic reference member so as to be movable forward and backward with respect to a reading position facing the image reading means. A gray balance adjustment coefficient calculation method executed by an apparatus,
A moving body control step of controlling the operation of the moving body during gray balance adjustment and moving the achromatic color reference member to the reading position;
A reading control step of reading the achromatic reference member by the image reading means at the time of gray balance adjustment;
A calculation step of calculating a gray balance adjustment coefficient of the image reading unit so as to be a target value for each of RGB colors according to a reading result of the reading control step;
The calculation method characterized by including. An inspection comprising: an achromatic reference member having a uniform gray patch having a constant density in the main scanning direction; and a moving body that holds the achromatic reference member so as to be movable forward and backward with respect to a reading position facing the image reading means. The computer that controls the device,
Moving body control means for controlling the operation of the moving body during gray balance adjustment and moving the achromatic color reference member to the reading position;
Reading control means for reading the achromatic reference member by the image reading means at the time of gray balance adjustment;
A calculation unit that calculates a gray balance adjustment coefficient of the image reading unit so as to be a target value for each color of RGB according to a reading result by the reading control unit;
Program to function as.

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