JP2014238495A - Image forming apparatus and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of performing a prioritized correction process, even when a plurality of correction processes are required, and to provide an image forming method.SOLUTION: The image forming apparatus used for image forming comprises: correction process means to perform a plurality of correction processes relating to the image forming; and determination means to determine whether a plurality of correction processes satisfying an execution condition exist or not. The correction process means performs the correction process which is selected on the basis of the levels of necessity of the plurality of correction processes which are determined on the basis of the state of the image forming apparatus, when the determination means determines that the plurality of correction processes satisfying the execution condition exist.

Description

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

  In recent years, various correction processes such as a color misregistration correction process and a density correction process are performed in an image forming apparatus.

  Further, in the conventional image forming apparatus, since it takes time to execute a plurality of correction processes, the time during which the image forming operation is stopped (so-called downtime, the same applies hereinafter) by efficiently executing the plurality of correction processes. Is described (for example, see Patent Document 1).

  Further, as a method for further shortening the downtime, conventionally, correction processing (so-called real-time correction processing, which will be described in the following) that is performed in parallel with the image forming operation using the outside of the image forming area is known (for example, Patent Document 2).

  In the conventional real-time correction process, since the control is complicated, it is difficult to perform a plurality of correction processes in parallel. Therefore, in the conventional real-time correction process, a preset correction process is executed. That is, in the conventional real-time correction process, there is a possibility that the correction process that should be preferentially executed when a plurality of correction processes are required is not performed.

  SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus and an image forming method capable of executing a correction process to be prioritized.

  An image forming apparatus according to an aspect is an image forming apparatus that performs image formation, and whether or not there are a plurality of correction processing units that perform a plurality of correction processes related to the image formation and a plurality of correction processes that satisfy the execution conditions. A determination unit that determines the plurality of correction processes based on the state of the image forming apparatus when it is determined that there are a plurality of correction processes that satisfy a condition to be executed by the determination unit. The correction process selected based on the necessity is executed.

  A correction process to be prioritized when a plurality of correction processes are required can be executed.

1 is a diagram illustrating an example of a schematic configuration of an image forming apparatus according to a first embodiment. It is a figure which shows an example of a structure of a detection sensor. 1 is a block diagram illustrating an example of a hardware configuration diagram of an image forming apparatus according to an embodiment of the present invention. 2 is a functional block diagram illustrating an example of a functional configuration of the image forming apparatus according to the first embodiment. FIG. It is a figure which shows an example of the corresponding | compatible table which matched the correction | amendment process and the conditions which can perform a correction | amendment process. It is a figure explaining an example of the detection of a test pattern and a pattern. It is a figure explaining an example of the various deviation | shift amount computed from a test pattern. FIG. 4 is a diagram illustrating an example in which detection units are arranged outside two image forming regions in the left-right direction from the conveyance direction of the intermediate transfer belt. It is a figure explaining an example of the execution timing of a some correction process. 6 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the first embodiment. It is a functional block diagram explaining an example of a function structure of the image forming apparatus which concerns on 2nd Embodiment. 12 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the second embodiment. 12 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the third embodiment.

Embodiments of the present invention will be described below.

<First Embodiment>
<Schematic configuration of image forming apparatus>
FIG. 1 is a diagram illustrating an example of a schematic configuration of the image forming apparatus according to the first embodiment. In the example of FIG. 1, an electrophotographic image forming apparatus having a secondary transfer mechanism called a tandem method in color image formation is shown.

  The image forming apparatus 1000 includes, for example, separate photosensitive drums (hereinafter, abbreviated as “photosensitive members”) corresponding to respective colors such as yellow (Y), cyan (C), magenta (M), and black (K). (Hereinafter, colors may be represented by symbols shown in parentheses as appropriate).

  The image forming apparatus 1000 is an image processing apparatus having, for example, a facsimile machine, a printing apparatus (printer), a copying machine, and a multifunction machine.

  The image forming apparatus 1000 includes an optical device 101, an image forming unit 102, and a transfer unit 103. The optical device 101, the image forming unit 102, and the transfer unit 103 perform image formation and test pattern formation.

  The optical device 101 deflects the light beam BM emitted from a plurality of light sources (not shown) by the polygon mirror 110 and makes the light beams BM enter the scanning lenses 111a and 111b. The scanning lenses 111a and 111b are, for example, fθ lenses.

  The number of light beams BM corresponds to each color of yellow (Y), black (K), magenta (M), and cyan (C). After passing through the scanning lenses 111a and 111b, the light beam BM is reflected by the reflection mirrors 112y to 112c.

  For example, the yellow light beam Y passes through the scanning lens 111a, is reflected by the reflection mirror 112y, and enters the WTL lens 113y. Since the other black, magenta, and cyan colors are the same, the description thereof is omitted here.

  The WTL lenses 113y to 113c shape the incident light beams Y to C and then deflect the light beams Y to C to the reflection mirrors 114y to 114c.

  The respective light beams Y to C deflected by the reflection mirrors 114y to 114c are reflected by the reflection mirrors 115y to 115c. After the reflection, the light beams Y to C are imagewise irradiated onto the photoconductors 120y to 120c for exposure.

  Irradiation of the light beams Y to C of the respective colors onto the photoconductors 120y to 120c uses a plurality of optical elements as described above. Therefore, timing synchronization is performed in the main scanning direction and the sub-scanning direction with respect to the photoconductors 120y to 120c.

  Hereinafter, the main scanning direction with respect to the photoconductors 120y to 120c is referred to as a light beam scanning direction. The sub-scanning direction with respect to the photoconductors 120y to 120c is a direction orthogonal to the main scanning direction, and the photoconductors 120y to 120c are rotated.

  The photoreceptors 120y to 120c have at least a charge generation layer, a charge transport layer, and a photoconductive layer on a conductive drum such as aluminum. The photoconductive layer is disposed corresponding to each of the photoconductors 120y to 120c, and includes a corotron, a scorotron, a charging roller, or the like. Surface charges are applied by the chargers 122y to 122c.

  The electrostatic charges applied to the photoreceptors 120y to 120c by the chargers 122y to 122c are imagewise exposed by the light beams Y to C, respectively. An electrostatic latent image is formed on the scanned surface of each of the chargers 122y to 122c.

  The developing devices 121y to 121c include a developing sleeve, a developer supply roller, a regulating blade, and the like. The electrostatic latent images formed on the scanned surfaces of the photoconductors 120y to 120c are developed by the developing units 121y to 121c, respectively. As a result, developer images are formed on the scanned surfaces of the photoreceptors 120y to 120c.

  The developers carried on the scanned surfaces of the photoreceptors 120y to 120c are transferred onto the intermediate transfer belt 130 that moves in the direction of arrow D by the transport rollers 131a to 131c. Reference numerals 132y to 132c denote primary transfer rollers for the photoreceptors 120y to 120c, respectively.

  The intermediate transfer belt 130 is conveyed to the secondary transfer unit while carrying Y, K, M, and C developers transferred from the scanned surfaces of the photoreceptors 120y to 120c, respectively. That is, the intermediate transfer belt 130 corresponds to an intermediate transfer member.

  The secondary transfer unit includes a secondary transfer belt 133 and conveying rollers 134a and 134b. The secondary transfer belt 133 is conveyed in the direction of arrow E by the conveyance rollers 134a and 134b.

  The recording medium P is supplied to the secondary transfer unit from the recording medium storage unit T such as a paper feed cassette by the transport roller 135. As the recording medium P, paper which is an image receiving material, high quality paper, a plastic sheet, a metal sheet, or the like is used. The secondary transfer unit applies a secondary transfer bias voltage to transfer the multicolor developer image carried on the intermediate transfer belt 130 onto the recording medium P held by suction on the secondary transfer belt 133.

  Next, the recording medium P is supplied to the fixing device 136 along with the conveyance of the secondary transfer belt 133.

  The fixing device 136 includes a fixing member 137 such as a fixing roller. The fixing roller is made of a member such as silicone rubber or fluorine rubber. The fixing device 136 pressurizes and heats the recording medium P and the multicolor developer image. Then, the recording medium P is discharged to the outside of the image forming apparatus 1000 by the paper discharge roller 138 as a printed material P2.

  After the multi-color developer image is transferred, the remaining transfer agent is removed from the intermediate transfer belt 130 by the cleaning unit 139. The cleaning unit 139 has a cleaning blade (not shown). After removal, the next image forming process is performed.

  In addition, three detection sensors (hereinafter also referred to as detection sensors) 5a to 5c are installed in the vicinity of the conveyance roller 131a.

  The detection sensors 5 a to 5 c detect the test pattern 30 formed on the intermediate transfer belt 130. Examples of the test pattern 30 include a color misregistration correction test pattern and a density correction processing test pattern.

  The detection sensors 5a to 5c are, for example, known reflection type photosensors. Various displacement amounts are calculated based on the detection results of the detection sensors 5a to 5c.

  The deviation amount is, for example, a skew deviation amount of each color with respect to the reference color, a main scanning registration deviation amount, a sub-scanning registration deviation amount, and a main scanning magnification error. Based on the deviation amount, various deviations are corrected. In the misalignment correction process, the image forming conditions (color misregistration, density, etc.) are corrected, and the test pattern 30 is formed under the corrected image forming conditions.

<Configuration of detection unit>
FIG. 2 is a diagram illustrating an example of the configuration of each of the detection sensors 5a to 5c illustrated in FIG. Here, the detection sensor 5a is illustrated. Since the detection sensors 5b and 5c are the same, description thereof is omitted.

  The detection sensor 5a includes one light emitting unit 10a, two light receiving units 11a and 12a, and a condenser lens 13a.

  The light emitting unit 10a is a light emitting element that emits light, and is, for example, an infrared LED (Light-Emitting Diode) that generates infrared light.

  The light receiving unit 11a is, for example, a regular reflection type light receiving element. The light receiving unit 12a is, for example, a diffuse reflection type light receiving element.

  The light L1 emitted from the light emitting unit 10a passes through the condenser lens 13a and then reaches the test pattern 30 (not shown) of the intermediate transfer belt 130.

  The light reaching the test pattern 30 is regularly reflected by the test pattern forming region and the toner layer in the test pattern forming region to become specularly reflected light L2. The regular reflection light L2 passes through the condenser lens 13a again and is received by the light receiving unit 11a.

  Further, the other part of the light is diffusely reflected by the test pattern forming region and the toner layer in the test pattern forming region to become diffusely reflected light L3. The diffuse reflected light L3 is retransmitted through the condenser lens 13a and received by the light receiving unit 12a.

  The light emitting element may be a laser light emitting element or the like instead of the infrared LED.

  Further, the light receiving portions 11a and 12a (regular reflection type light receiving element, diffuse reflection type light receiving element) may include a photodiode or an amplifier circuit.

<Hardware configuration>
FIG. 3 is a block diagram illustrating an example of a hardware configuration diagram of an image forming apparatus according to an embodiment of the present invention.

  The detection sensors 5a to 5c of the image forming apparatus 1000 include light emitting units 10a to 10c and light receiving units 11a to 11c and 12a to 12c, respectively. The condenser lenses 13a to 13c shown in FIG. 2 are not shown in FIG.

  The image forming apparatus 1000 includes a CPU (Central Processing Unit) 1, a ROM (Read-Only Memory) 2, a RAM (Random Access Memory) 3, and an input / output (hereinafter abbreviated as “I / O”). ) Port 4, light emission amount control units 14 a to 14 c, amplification units (Amplifier (hereinafter abbreviated as “AMP”)) 15 a to 15 c, and filter units 16 a to 16 c. The image forming apparatus 1000 includes an analog-digital (analog-digital (hereinafter abbreviated as “A / D”)) converters 17a to 17c, a first-in first-out (hereinafter, referred to as “first-in-first-out”). Abbreviated as “FIFO”)) having memory units 18a to 18c and sampling control units 19a to 19c.

  The ROM 2 stores various programs executed by the CPU 1 when an image is formed on the intermediate transfer belt 130.

  Various programs executed by the CPU 1 include, for example, correction processing, shift amount calculation processing for calculating a shift amount in the main scanning direction, processing for controlling the image forming apparatus 1000, and the like.

  The CPU 1 and the ROM 2 function as a control unit that controls the operation of the entire image forming apparatus.

  The CPU 1 executes various programs stored in the ROM 2 using the RAM 3 as a work area.

  Further, the CPU 1 monitors detection signals from the light receiving units 11a to 11c. Therefore, it is possible to detect deterioration of the transport belt and the light emitting units 10a to 10c.

  Further, the CPU 1 controls the light emission amount by the light emission amount control units 14a to 14c so that the level of the light reception signal from the light receiving unit is always constant.

  Next, processing of data detected by the detection sensors 5a to 5c will be described.

  The CPU 1 controls the light emission amount control units 14 a to 14 c via the I / O port 4 by detecting the test pattern 30. A light beam having a predetermined light amount is emitted from each of the light emitting units 10a to 10c of the detection sensors 5a to 5c.

  The light beam emitted from the light emitting unit 10a of the detection sensor 5a is applied to the test pattern 30, and the reflected light is received by the light receiving units 11a and 12a of the detection sensor 5a.

  The light receiving units 11a and 12a send data signals corresponding to the amounts of received light beams to the amplification unit 15a. The amplifying unit 15a amplifies the data signal sent from the light receiving units 11a and 12a and sends the amplified data signal to the filter unit 16a.

  The filter unit 16a passes only the signal component of the line detection to the data signal sent from the amplification unit 15a, and sends it to the A / D conversion unit 17a. The A / D conversion unit 17a converts the data signal sent from the filter unit 16a from analog data to digital data. The sampling control unit 19a samples the digital data converted by the A / D conversion unit 17a and stores it in the FIFO memory unit 18a.

  Similarly, the CPU 1 also processes data signals obtained from the light receiving portions 11b and 12b of the detection sensor 5b.

  The test pattern 30 can be detected by processing as described above. After the test pattern 30 is detected, the data stored in the FIFO memory unit 18 is loaded into the CPU 1 and the RAM 3 via the I / O port 4.

  The CPU 1 performs predetermined calculation processing to obtain a color misregistration correction processing amount. Details will be described later.

  The ROM 2 stores a program for calculating a color misregistration correction processing amount, and various programs for controlling the color misregistration correction processing apparatus and the image forming apparatus.

  The CPU 1 sets the image forming unit 6 such as setting the writing start timing and changing the pixel clock frequency based on the correction processing amount calculated from the detection of the test pattern 30 and the test pattern for color matching.

  The image forming unit 6 is a device that can set an output frequency. For example, a clock generator using a VCO (Voltage Controlled Oscillator) can be used as a pixel clock generation unit.

Based on this pixel clock, an image is written by controlling the lighting of an LD (Laser Diode) according to the image data sent from the controller unit 7.
<Overall configuration of image forming apparatus: block diagram>
FIG. 4 is a functional block diagram illustrating an example of a functional configuration of the image forming apparatus according to the first embodiment.

  The correction processing executed in the image forming apparatus 1000 of the present embodiment includes two types of correction processing, for example, density correction processing and color misregistration correction processing. It is determined whether or not the density correction and color misregistration correction processing of the present embodiment is executed according to the linear velocity described later. In this embodiment, the linear speed is the conveyance speed of the intermediate transfer belt 130, that is, the feeding speed of the recording medium in the sub-scanning direction. Correspondingly, it is set in the image forming apparatus 1000. Depending on the adjustment of the image forming apparatus 1000, for example, the corresponding linear speed may be different even in the same operation mode.

  In the image forming apparatus 1000 of the present embodiment, each process such as a measurement process, a correction process, and a determination process, which will be described later, is executed by the CPU 1. The CPU 1 includes a measurement unit 151, a determination unit 152, and a correction processing unit 153.

  The measurement unit 151 acquires data from each sensor (not shown) that measures temperature and detects a recording medium. The measurement unit 151 measures the number of image formations, the temperature in the apparatus, the number of recording media on which image formation has been performed, the elapsed time, and the like based on the acquired data of each sensor. Note that image formation in this embodiment refers to image formation for one page of a recording medium.

  The measurement unit 151 includes an image formation number measurement unit 1511, a temperature measurement unit 1512, a number measurement unit 1513, and a time measurement unit 1514.

  The image formation number measurement unit 1511 counts the number of image formations performed by the image forming apparatus 1000. The value counted by the image formation number measurement unit 1511 is notified to the measurement data holding unit 1525 as measurement data and held.

  The temperature measurement unit 1512 measures temperature data in or around the image forming apparatus 1000. The temperature data measured by the temperature measurement unit 1512 is notified to the measurement data holding unit 1525 as measurement data and held.

  The number counting unit 1513 counts the number of recording media on which the image forming apparatus 1000 has formed an image, and the value counted by the temperature measuring unit 1512 is notified to the measurement data holding unit 1525 as measurement data and held.

  The time measurement unit 1514 measures time data such as a time when the image forming apparatus 1000 is activated and an elapsed time since the previous image formation. The time data measured by the time measurement unit 1514 is notified to the measurement data holding unit 1525 as measurement data and held.

  Note that the measurement data notified from the measurement unit 151 of this embodiment to the determination unit 152 may be a difference value from the previous image formation or the previous correction process.

  When the determination unit 152 acquires a correction processing execution notification signal notified from the correction processing unit 153 when the correction processing is executed in the correction processing unit 153 described later, the determination unit 152 uses the signal as a reset signal as a measurement data holding unit. The measurement data held in 1525 may be reset. In the present embodiment, the measurement data held in the measurement data holding unit 1525 is measured after the previous correction process is executed by resetting the measurement data when the correction processing is executed in the correction processing unit 153. Can be a value.

  The determination unit 152 includes a density correction processing flag data holding unit 1521, a color misregistration correction processing flag data holding unit 1522, an execution condition determination unit 1523, a necessity determination unit 1524, and a measurement data holding unit 1525. The correction process to be executed is determined based on the measurement data notified from the measurement unit 151, and the determination result of the correction process to be executed is notified to the correction processing unit 153.

  Specifically, the determination unit 152 of the present embodiment determines whether to execute density correction processing or color misregistration correction processing based on the number of times of image formation from the previous execution of correction processing, and performs the determined execution. The correction processing unit 153 is notified of the determination result of the correction process.

  The determination unit 152 is an example of a determination unit.

  A process for determining the correction process executed by the determination unit 152 will be described below.

  The determination unit 152 of this embodiment has two storage areas corresponding to density correction processing and color misregistration correction processing in the measurement data holding unit 1525. The measurement data holding unit 1525 holds the count value of the number of times of image formation from the previous execution of the correction process measured by the image formation number measurement unit 1511.

  The determination unit 152 according to the present embodiment refers to, for example, the count value held in the measurement data holding unit 1525 corresponding to the density correction process, and the count value exceeds a predetermined value TL1 for the density correction process set in advance. In this case, it is determined that the density correction process needs to be executed. At this time, the determination unit 152 sets ON flag data in the density correction processing flag data holding unit 1521, and the density correction processing flag data holding unit 1521 holds the flag data.

  Similarly, the determination unit 152 refers to the count value held in the measurement data holding unit 1525 corresponding to the color misregistration correction process, and the count value exceeds a predetermined value TL2 for color misregistration correction processing set in advance. Then, it is determined that the color misregistration correction process needs to be executed. At this time, the determination unit 152 sets ON flag data in the color misregistration correction processing flag data holding unit 1522, and the color misregistration correction processing flag data holding unit 1522 holds the flag data.

  The determination unit 152 according to the present embodiment resets the count value corresponding to the density correction processing held in the measurement data holding unit 1525 to 0 when the density correction processing is executed in the correction processing unit 153. Further, the determination unit 152 of the present embodiment uses the ON flag data held in the density correction processing flag data holding unit 1521 as OFF flag data.

  Similarly, the determination unit 152 of the present embodiment resets the count value corresponding to the color misregistration correction process held in the measurement data holding unit 1525 to 0 when the color misregistration correction process is executed in the correction processing unit 153. . Further, the determination unit 152 according to the present embodiment sets the ON flag data held in the color misregistration correction processing flag data holding unit 1522 as OFF flag data.

  In the present embodiment, the number of flag data and flag data holding units is two corresponding to the density correction processing and the color misregistration correction processing, but the number of flag data and flag data holding units is the correction processing unit 153. Corresponds to the number of types of correction processing that can be executed. Therefore, if there are three types of correction processing that can be executed by the correction processing unit 153, the number of flag data and flag data holding units is three.

  The execution condition determination unit 1523 of this embodiment determines whether or not the necessary correction processing is performed. The execution condition determination unit 1523 of this embodiment determines whether the correction processing unit 153 can execute the correction process based on the execution condition of the image forming apparatus 1000 in the correspondence table 50 described later. Further, when the correction process corresponding to the ON flag can be executed, the correction process corresponding to the ON flag is determined as a necessary correction process.

  FIG. 5 is a diagram illustrating an example of a correspondence table in which correction processing is associated with conditions under which correction processing can be performed.

  In this embodiment, the linear velocity of the image forming apparatus 1001 is referred to as an execution condition. In the correspondence table 50 shown in FIG. 5, for example, when the execution condition is the linear velocity 1, the correction processing unit 153 can execute density correction processing and color misregistration correction processing. Similarly, in the correspondence table 50, when the execution condition is the linear velocity 2, only the density correction process can be executed by the correction processing unit 153. Further, when the execution condition is the linear velocity 4, only the color misregistration correction process can be executed by the correction processing unit 153.

  Note that the correspondence table 50 of the present embodiment is stored in advance in a storage area (not shown) of the CPU 1. The linear velocities 1 to 4 in the present embodiment indicate the respective stages when the linear velocities are distinguished into four stages. The stage of the linear velocity is set according to a plurality of thicknesses of transfer paper as a recording medium and the operation mode of the image forming apparatus 1000.

  The necessity determination unit 1524 according to the present embodiment is a case where the execution condition determination unit 1523 according to the present embodiment determines that both correction processing of density correction processing and color misregistration correction processing are necessary correction processing by the correction processing unit 153. The correction process to be executed is determined based on the necessity of each correction process. That is, when there are a plurality of necessary correction processes, the necessity level determination unit 1524 according to the present embodiment determines a correction process to be executed based on the level of necessity corresponding to each correction process. Specific determination will be described later.

  The necessity determination unit 1524 of the present embodiment uses the measurement data held in the measurement data holding unit 1525 as the necessity. More specifically, the necessity determination unit 1524 of the present embodiment uses the measurement data held in the measurement data holding unit 1525 corresponding to each correction process of the density correction process and the color misregistration correction process as the necessity level. The necessity determination unit 1524 according to the present embodiment determines a correction process to be executed by comparing the necessity of each correction process. More specifically, a correction process for executing any one of the density correction process and the color misregistration correction process by comparing the degree of necessity corresponding to each correction process of the density correction process and the color misregistration correction process to be described later. judge. The necessity determination unit 1524 according to the present embodiment notifies the correction processing unit 153 of the determined correction processing as a determination result of the correction processing to be executed.

  The correction processing unit 153 includes a density correction processing unit 1531 and a color misregistration correction processing unit 1532, and executes each correction process.

  The correction processing unit 153 is an example of a correction processing unit that executes a plurality of correction processes related to image formation.

  The correction processing unit 153 receives the notification of the correction processing execution command from the controller unit 7, selects and executes the correction processing to be executed based on the determination result of the correction processing executed by the necessity determination unit 1524. The correction process to be executed is selected based on the determination result of the correction process to be executed notified by the determination unit 152, and the correction process is executed. The correction processing unit 153 according to the present embodiment performs the color misregistration correction processing by the color misregistration correction processing unit 1532 in response to the notification of the determination result of the correction performed by the determining unit 152.

  In the present embodiment, the correction processing executed in the correction processing unit 153 is the density correction processing and the color misregistration correction processing, but is not limited thereto. The correction processing unit 153 includes a charging AC sub correction processing unit (not shown) that executes charging AC sub correction processing, a toner refresh correction processing unit (not shown) that executes toner refresh correction processing, and ACC ( An ACC correction processing unit (not shown) that executes AutoColorCalibration (hereinafter referred to as ACC correction processing) may be included.

The charging AC sub correction process is executed when the potential of the photoconductor 120 changes due to a change in temperature or a change with time, for example, by a contact method using the charger 122. The charging AC sub correction process is a correction process for adjusting the current value of the charging roller in the charger 122 so as to obtain an appropriate potential stored in advance. The toner refresh correction process is a correction process for performing a process of consuming toner staying for a long time (so-called deteriorated toner) based on the amount of toner used per area and the elapsed time in image formation. The ACC correction process corrects the density and color that change due to temperature changes and changes with time.
<Color shift correction processing>
In the color misregistration correction process, the CPU 1 calculates a correction processing amount from the test pattern 30, and the correction process is executed based on the correction processing amount calculated by the color misregistration correction processing unit 1532. FIG. 6 is a diagram for explaining an example of the test pattern 30 and pattern detection. The test pattern 30 includes a horizontal line pattern and a diagonal line pattern of each color of Y, K, M, and C.

  The horizontal line pattern is a pattern having a predetermined width and a predetermined length in a direction orthogonal to the main scanning direction of the photoconductors 120y to 120c.

  The oblique line pattern is a pattern having a predetermined width and a predetermined length with a predetermined inclination angle (for example, 45 °) with respect to the main scanning direction of the photoconductors 120y to 120c.

  A total of eight patterns of horizontal line patterns and diagonal line patterns of each color are taken as one set of test patterns 30. Two sets of test patterns 30 are arranged in the sub-scanning direction to form one row of test patterns 30.

  FIG. 6B is an example of a test pattern including three rows of test patterns 30 corresponding to the installation positions of the detection sensors 5a to 5c. The test pattern 30 is transferred onto the intermediate transfer belt 130 by the photoconductors 120y to 120c in the arrangement as described above.

  Dotted lines 31a to 31c shown in FIG. 6B show examples of the locus of the positions of the detection sensors 5a to 5c when the intermediate transfer belt 130 is conveyed in the sub-scanning direction.

  6 and FIG. 7 to be described later, each horizontal line pattern and each diagonal line pattern are arranged so that the test pattern 30 is arranged on the intermediate transfer belt 130 in the order of Y, K, M, and C from the beginning in the conveyance direction of the intermediate transfer belt 130. An example in which It should be noted that the color arrangement of each horizontal line pattern and each diagonal line pattern constituting the test pattern 30 may be arranged in other ways.

  The detection sensors 5a to 5c detect the test pattern 30 formed on the intermediate transfer belt 130.

  FIG. 6A shows the detection value of the detection sensor 5. The detection sensor 5 detects the intermediate transfer belt 130 at a portion other than the pattern formed, and outputs a detection value corresponding to the color of the intermediate transfer belt 130. For example, when the intermediate transfer belt 130 is white and the intermediate transfer belt 130 is being detected, the detection sensor 5 outputs a detection value corresponding to white. A detection value output from the detection sensor 5 when the intermediate transfer belt 130 is detected is set as a reference level.

  Since the pattern has any one color of Y, K, M, and C, the detection value output by the detection sensor 5 when detecting the location of the pattern is a detection value lower than the reference level.

  A broken line in (a) of FIG. 6 indicates a threshold voltage level (voltage value). The threshold voltage level is a value serving as a reference for determining whether or not the detection value output from the detection sensor 5 is a value obtained by detecting a pattern.

  For example, even when the detection value output from the detection sensor 5 detects the intermediate transfer belt 130 due to contamination of the intermediate transfer belt 130, the output detection value may decrease. The threshold voltage level is a threshold value for discriminating pattern detection when the detection value output from the detection sensor 5 falls below the threshold voltage level even when the detection value output from the detection sensor 5 is reduced. . By determining whether or not the detection value output from the detection sensor 5 is a value obtained by detecting a pattern with reference to the threshold voltage level, erroneous detection of the detection sensor 5 due to contamination of the intermediate transfer belt 130 is prevented. be able to.

  The detection sensor 5 detects the test pattern 30, and the CPU 1 measures various shift amounts of other colors (yellow: Y, cyan: C, magenta: M) with respect to a reference color (for example, black: K). The various shift amounts are, for example, a skew shift amount, a main scanning registration shift amount, a sub-scanning registration shift amount, and a main scanning magnification error. Various displacement amounts and a method for calculating the displacement amount will be described later.

  Various displacement amounts are measured by the CPU 1 using the installation center position of the detection sensor 5 and the pattern center position as displacement amounts, and the various displacement amounts are used to calculate correction processing values used for correction processing. The calculated correction processing amount is stored in a correction processing unit that executes each correction process. The calculation of the correction process value will be described later.

  Note that the CPU 1 may calculate an average value of various deviation amounts in the three rows of the test pattern 30 and use the calculated average value as various deviation amounts. By using the average value, the shift amount of each color can be accurately measured, and a high-quality image can be formed.

  The correction processing unit 153 executes correction processing based on the calculated correction processing amount. When the measurement of various displacement amounts is completed, the test pattern 30 used for the measurement is removed from the intermediate transfer belt 130 by the cleaning unit 139 in FIG.

  FIG. 7 is a diagram for explaining an example of various displacement amounts calculated from the test pattern 30.

  A method for calculating various displacement amounts when the test pattern 30 is detected by the detection sensor 5a will be described. In addition, since the method of calculating the deviation | shift amount with the other detection sensors 5b and 5c is the same as that of the detection sensor 5a, description is abbreviate | omitted.

  The detection sensor 5a performs pattern detection at a predetermined sampling time interval. The detection sensor 5a notifies the detection result to the CPU 1 in FIG. The CPU 1 calculates the distances y1, m1, c1, y2, k2, m2, and c2 between the patterns based on the detection result interval and the sampling time interval. The CPU 1 calculates the amount of deviation based on the calculated distance between patterns.

  Various displacement amounts will be described.

  A horizontal line pattern is used to calculate the sub-scanning registration shift amount (color shift amount in the sub-scan direction).

  The CPU 1 calculates values (y1, m1, c1) of distances between the reference color (K) and the patterns of the colors Y, M, and C. Next, the CPU 1 calculates the difference between the distance values (y1, m1, c1) between the patterns and the ideal interval values (y0, m0, c0) stored in advance.

  Specifically, the CPU 1 calculates an interval value y1-an ideal interval value y0, an interval value m1-an ideal interval value m0, an interval value c1-an ideal interval value c0, and thereby each color Y with respect to the reference color (K). , M, and C sub-scanning registration deviation amounts are calculated.

  The horizontal scanning pattern and the diagonal line pattern are used to calculate the main scanning registration shift amount (color shift amount in the main scanning direction).

  The CPU 1 calculates an interval value (y2, k2, m2, c2) between the horizontal line pattern and the diagonal line pattern of each color K to C. Specifically, the CPU 1 calculates the difference between the interval value of the reference color (K) and the interval values of the colors Y, M, and C based on the calculated interval value, so that each color Y with respect to the reference color (K) is calculated. , M, and C main scanning registration deviation amounts can be calculated.

  When there is a deviation in the main scanning direction, the diagonal line pattern is inclined by a predetermined angle with respect to the main scanning direction, so that the interval with the horizontal line pattern becomes wider or narrower than the interval of the other colors. Therefore, main scanning registration deviation occurs.

  Specifically, the CPU 1 has black and yellow, black and magenta, and black and cyan main scanning registration misregistration amounts of an interval value k2 to an interval value y2, an interval value k2 to an interval value m2, and an interval value k2 to an interval value c2. calculate. In this way, the registration deviation amount in the sub-scanning direction and the main scanning direction can be calculated.

  Furthermore, the skew deviation amount and the main scanning magnification error can also be calculated based on the detection results of different detection sensors 5a to 5c.

  The skew deviation amount is calculated by the CPU 1 from the difference between the sub-scanning registration deviation amounts of the detection sensors 5a and 5c.

  The magnification error deviation is calculated by the CPU 1 from the difference between the main scanning registration deviation amounts of the detection sensors 5a and 5b and the detection sensors 5b and 5c.

  The CPU 1 calculates a correction processing amount based on the calculated positional deviation amount, and executes the correction processing. The correction process corrects image forming conditions and the like when forming a color image on the intermediate transfer belt 130.

  In the correction processing, for example, the correction processing unit 153 calculates the correction processing amount so as to adjust the light emission timings of the light beams Y to C corresponding to the respective colors with respect to the photoconductors 120y to 120c so that the deviation amounts substantially coincide with each other. Execute correction processing.

Further, the correction process may be executed by driving a stepping motor (not shown) to adjust the inclination of the reflecting mirror (not shown). The image forming unit 6 may change the image data based on the correction processing amount and execute the correction processing.
<Density correction processing>
The density correction process will be described. The image forming section 6 forms a gradation test pattern for density correction processing set in advance, and a density sensor (not shown) detects the density value of the formed test pattern. The density correction process is a correction process for changing image forming process conditions such as laser power, charging bias, and developing bias of the image forming apparatus so that the detected density value becomes a preset value.
<Real-time correction processing>
In the real-time correction process, the test pattern 30 is formed in an area other than the area where the image forming unit 6 performs image formation (hereinafter referred to as “image forming area”), and the amount of correction processing is performed by the above-described color misregistration correction method. Is calculated and correction processing is performed.

  In the case of real-time correction processing, at least one detection unit 5 is arranged outside the image forming area in the main scanning direction. The arrangement position of the detection unit 5 corresponds to the position where the test pattern 30 is formed.

  FIG. 8 is a diagram illustrating an example in which the detection units 5a and 5c are arranged outside two image forming regions in the left-right direction from the conveyance direction of the intermediate transfer belt.

  In the real-time correction process, since the correction processing unit 153 can execute the correction process even when the image forming unit 6 is performing image formation, the image forming apparatus reduces the occurrence of downtime and the productivity of the image forming apparatus is reduced. Can be reduced.

When the test pattern 30 is formed outside the image forming area, the test pattern 30 may be formed at any position. The detection unit 5 is installed corresponding to a position where the test pattern 30 can be detected.
<Determination method of correction processing to be executed>
FIG. 9 is a diagram illustrating an example of execution timings of a plurality of correction processes. In the example of FIG. 9, the timing at which the correction processing unit 153 executes each correction process when the execution condition changes between linear velocities 1 to 3 will be described.

  First, a case where the execution condition is a linear velocity 1 will be described. When the execution condition is the linear velocity 1, correction processing that can be executed by the correction processing unit 153 is color misregistration correction processing and density correction processing (see FIG. 5).

  In FIG. 9, when the count value corresponding to the density correction process held in the measurement data holding unit 1525 reaches the predetermined value TL1 at the timing T1, the correction processing unit 153 executes the density correction process. Further, the count value corresponding to the density correction processing held in the measurement data holding unit 1525 is reset to zero.

  Similarly, in FIG. 9, when the count value corresponding to the color misregistration correction process held in the measurement data holding unit 1525 reaches the predetermined value TL2 at the timing T2, the correction processing unit 153 executes the color misregistration correction process. Further, the count value corresponding to the color misregistration correction process held in the measurement data holding unit 1525 is reset to zero.

  When the execution condition is the linear velocity 1, since the correction processing unit 153 can execute the density correction process and the color misregistration correction process, the correction processing unit 153 is held in the density correction flag data holding unit 1521 and the color misregistration correction flag data holding unit 1522. The flag data may remain OFF. That is, the density correction flag data holding unit 1521 and the color misregistration correction flag data holding unit 1522 according to this embodiment may hold ON flag data only when the corresponding correction process is not executed by the correction processing unit 153. .

  Next, the case where the execution condition is the linear velocity 2 will be described. When the execution condition is the linear velocity 2, the correction process that can be executed by the correction unit 153 is a density correction process (see FIG. 5).

  In FIG. 9, when the count value corresponding to the density correction processing held in the measurement data holding unit 1525 reaches the predetermined value TL1 at timing T3, the correction processing unit 153 executes the density correction processing. Further, the count value corresponding to the density correction processing held in the measurement data holding unit 1525 is reset to zero. The count value corresponding to the color misregistration correction process held in the measurement data holding unit 1525 reaches the predetermined value TL2 at timing T4. However, since the execution condition is the linear velocity 2, the correction processing unit 153 does not execute the color misregistration correction process. Therefore, the determination unit 152 causes the color misregistration correction flag data holding unit 1522 to hold ON flag data.

  Next, the case where the execution condition is the linear velocity 3 will be described. When the execution condition is the linear velocity 3, the correction processing unit 153 cannot execute the correction process in both the density correction process and the color misregistration correction process (see FIG. 5).

  Therefore, even when the count value corresponding to the density correction process held in the measurement data holding unit 1525 reaches the predetermined value TL1 at the timing T5, the correction unit 153 does not execute the density correction process. Also, the determination unit 152 causes the density correction flag data holding unit 1521 to hold ON flag data.

  Next, the case where the execution condition returns to the linear velocity 1 at timing T6 will be described. When the execution condition is changed from the linear speed 3 to the linear speed 1 at the timing T6, the correction unit 153 can execute the correction process of the density correction process and the color misregistration correction process. At timing T 6, ON flag data is held in the density correction flag data holding unit 1521 and the color misregistration correction flag data holding unit 1522. Therefore, the correction processing necessary at timing T6 is density correction processing and color misregistration correction processing.

  Here, the determination unit 152 of the present embodiment causes the necessity determination unit 1524 to compare the necessity of each correction process, and causes the necessity determination unit 1524 to determine a correction process to be executed. Specifically, the respective necessity levels of the density correction process and the color misregistration correction process are compared, and the correction process is determined to execute the correction process with the higher necessity level.

  At timing T6, the count value corresponding to the density correction processing held in the measurement data holding unit 1525 is K1. At the timing T6, the count value corresponding to the color misregistration correction process held in the measurement data holding unit 1525 is K2. In FIG. 9, the density correction process is not executed after timing T3, and the color misregistration correction process is not executed after timing T2. Therefore, at the timing T6, the count value K2 corresponding to the color misregistration correction process held in the measurement data holding unit 1525 is larger than K1.

  Therefore, the necessity determination unit 1524 of the present embodiment assumes that the necessity of color misregistration correction processing is high as a result of comparison, and notifies the correction processing unit 153 of the determination result of correction processing executed with the content to be color misregistration correction processing. . The correction processing unit 153 performs the color misregistration correction process based on the notification of the determination result of the correction process to be executed.

  As described above, the determination unit 152 according to the present embodiment determines the correction to be performed based on the necessity level of each of the plurality of correction processes when the correction process is determined to require a plurality of correction processes. In 153, correction processing is executed.

  An example of the operation of the image forming apparatus 1000 according to this embodiment will be described below with reference to FIG. FIG. 10 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the first embodiment.

  In the image forming apparatus 1000 of this embodiment, the CPU 1 accepts an image formation request from the controller unit 7 (step S1001). The CPU 1 accepts an image formation request when an image formation instruction for image data input to the image forming apparatus 1000 is issued, for example. Further, when the CPU 1 of this embodiment does not accept an image formation request, the correction unit 153 may execute the correction process in downtime.

  Subsequently, the execution condition determination unit 1523 of the present embodiment acquires execution conditions set in the image forming apparatus 1000 of the present embodiment (Step S1002). The execution condition of this embodiment is a linear velocity. Next, the execution condition determination unit 1523 of the present embodiment acquires flag data corresponding to each correction process from the flag data holding unit of each correction process (step S1003).

  Next, the execution condition determination unit 1523 determines whether there are a plurality of necessary correction processes (step S1004). Specifically, the execution condition determination unit 1523 of the present embodiment associates the execution condition acquired in step S1002 with the correction process in which the flag data holding unit of each correction process holds ON flag data in the correspondence table 50. It is determined whether or not execution is possible. The execution condition determination unit 1523 according to the present embodiment determines that a correction process that can be executed and holds ON flag data is a necessary correction process. Furthermore, when there are a plurality of necessary correction processes, the process proceeds to a process for determining the correction process to be executed by the necessity determination unit 1524 using the necessary degree (YES in step S1004). If there are not a plurality of necessary correction processes, it is determined whether or not the color misregistration correction process is a correction process (NO in step S1004).

  In the case of YES in step S1004, the necessity determination unit 1524 determines the correction to be executed based on the necessity of each of the plurality of correction processes among the plurality of necessary correction processes. Specifically, the necessity determination unit 1524 determines the correction to be executed based on whether or not the degree of necessity of the color misregistration correction process is greater than or equal to the degree of necessity of the density correction process (step S1005).

  When the necessary degree of color misregistration correction processing is equal to or higher than the necessity degree of density correction processing (YES in step S1005), the necessity degree determination unit 1524 corrects the determination result of the correction processing executed with the content to be color misregistration correction processing. The correction processing unit 153 executes the color misregistration correction process (step S1006) and ends the process.

  If the degree of color misregistration correction processing is not equal to or higher than the level of density correction processing (NO in step S1005), the necessity determination unit 1524 uses the correction processing determination result of the correction processing to be executed as the content to be density correction processing. The correction processing unit 153 executes density correction processing (step S1007), and ends the processing.

  Hereinafter, the processing of steps S1004 to 1007 will be described more specifically.

  For example, consider a case where the CPU 1 receives an image formation request at timing T6 in FIG.

  The execution condition of the timing T6 is the linear velocity 1. Therefore, the determination unit 152 refers to the correspondence table 50 and determines that the correction processing corresponding to the execution condition of the timing T6 is the density correction processing and the color misregistration correction processing. At timing T6, the flag data for each correction process is ON. Therefore, the determination unit 152 determines that there are a plurality of executable correction processes at the timing T6.

  Subsequently, the necessity determination unit 1524 determines the correction process to be executed based on the necessity of the density correction process and the color misregistration correction process. In the present embodiment, the degree of necessity is the number of image formations from the previous correction process. Therefore, the necessity of density correction processing is K1, and the necessity of color misregistration correction processing is K2.

  In the present embodiment, since K2 is a larger value, the necessity determination unit 1524 determines that the correction process to be executed is the color shift correction process because the color shift correction process is more necessary. Therefore, the determination unit 152 causes the correction unit 153 to perform color misregistration correction processing. The necessity determination unit 1524 determines that the correction process for executing the density correction process is performed when K2 is not greater than K1, and causes the correction unit 153 to execute the density correction process.

  If NO in step S1004, the determination unit 152 determines whether the correction process requires color misregistration correction processing (step S1008). Specifically, the determination unit 152 determines whether or not the execution condition acquired in step S1002 is the linear velocity 1 or the linear velocity 4 and the flag data set in the color misregistration correction flag data holding unit 1522 is ON. judge.

  When the execution condition acquired in step S1002 is the linear velocity 1 or the linear velocity 4, and the flag data set in the color misregistration correction flag data holding unit 1522 is ON (YES in step S1008), the determination unit 152 The correction unit 153 is caused to execute color misregistration correction processing (step S1009), and the processing ends.

  When the execution condition acquired in step S1002 is the linear velocity 1 or the linear velocity 4, and the flag data set in the color misregistration correction flag data holding unit 1522 is not ON (NO in step S1008), the determination unit 152 It is determined whether or not correction processing requires correction processing (step S1010). Specifically, the determination unit 152 determines whether or not the execution condition acquired in step S1002 is the linear velocity 2 or the linear velocity 3 and the flag data set in the density correction flag data holding unit 1521 is ON. To do.

  When the execution condition acquired in step S1002 is the linear velocity 2 or the linear velocity 3, and the flag data set in the density correction flag data holding unit 1521 is ON (YES in step S1010), the determination unit 152 performs correction. The density correction process is executed by the unit 153 (step S1011), and the process ends. When the execution condition acquired in step S1002 is the linear velocity 2 or the linear velocity 3, and the flag data set in the density correction flag data holding unit 1521 is not ON (NO in step S1010), the correction unit 153 performs the correction process. The process is terminated without executing.

  As described above, in the present embodiment, when there are a plurality of necessary correction processes, the correction process to be executed can be determined according to the degree of necessity according to the state of image formation such as the number of image formations. Therefore, in this embodiment, when there are a plurality of necessary correction processes, the correction process to be prioritized can be executed.

  In the present embodiment, the degree of necessity is the number of times of image formation from the previous correction process, but is not limited to this. In the present embodiment, instead of the number of image formations, the amount of temperature change, the number of output recording media, and the elapsed time may be used as necessary.

Second Embodiment
In the second embodiment, the image forming apparatus 1001 in FIG. 11 is used. In the image forming apparatus 1001 shown in FIG. 11, the same components as those in the image forming apparatus 1000 shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. explain.

  The necessity calculation determination unit 1526 calculates the necessity of each correction process by a method to be described later based on the weighting coefficient and the measurement data. The necessary degree calculation determination unit 1526 is an example of a calculating unit that calculates the necessary degree by multiplying the measurement data and the weighting coefficient.

  The weighting factor setting unit 1527 sets a weighting factor for each correction process. For example, a service person of the image forming apparatus 1000 sets a weighting factor for each correction process in setting work of the image forming apparatus.

  FIG. 12 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the second embodiment.

  The processing of the flowchart shown in FIG. 12 differs from the processing of the flowchart of FIG. 10 in the processing of S1205, S1206, and S1207.

  Therefore, the processing of S1001 to S1004 in FIG. 10 is the same as the processing of S1201 to S1204 in FIG. 12, and the processing of S1006 to S1011 in FIG. 10 is the same as the processing of S1207 to S1213 in FIG. Therefore, the description is omitted.

  The necessity calculation determination unit 1526 acquires the weighting coefficient W1 of the color misregistration correction process and the weighting coefficient W2 of the density correction process, which are the weighting coefficients of each correction process, from the weighting coefficient setting unit 1527 (S1205).

  The necessity calculation determination unit 1526 multiplies the necessity N1 of the color misregistration correction process and the necessity N2 of the density correction process by the weighting factors W1 and W2 of each correction process and the measurement data of each correction process acquired from the measurement unit 151. To calculate.

For example, in the case of FIG. 9, the number of image formations P1 and P2 from the last time of each correction process is acquired from the image formation number measurement unit 1511, and each correction process is required using the following (Formula 1) and (Formula 2). The degree is calculated (S1206).
N1 = W1 × P1 (Formula 1)
N2 = W2 × P2 (Formula 2)
The necessary degree calculation determining unit 1526 determines a correction process to be executed by comparing the calculated necessary degrees N1 and N2 (S1207).

  In the present embodiment, by setting the weighting coefficient for each correction process, the correction processing unit 153 can preferentially execute the correction process suitable for the user and the use environment.

  The necessity calculation determination unit 1526 uses the number of image formations from the previous time of each correction process used for calculation of the necessity in step S1206 as the temperature change amount, the number of image-formed recording media, and the elapsed time. The degree of necessity may be calculated based on the correction process to determine a correction process to be prioritized.

<Third Embodiment>
In the third embodiment, the image forming apparatus 1001 of the second embodiment is used. Therefore, the description of the configuration and functional block diagram of the image forming apparatus is omitted.

  FIG. 13 is a flowchart illustrating an example of a flow of a series of operations performed by the image forming apparatus according to the third embodiment.

  The processing of the flowchart shown in FIG. 13 differs from the processing of the flowchart of FIG. 12 in the processing of S1305, S1306, and S1307. Accordingly, the processing of S1301 to S1304 in FIG. 13 is the same as the processing of S1201 to S1204 in FIG. 12 of the second embodiment, and the processing of S1308 to S1314 in FIG. 13 is S1207 in FIG. 12 of the second embodiment. This process is the same as the process in S1213.

  In the third embodiment, the necessity calculation determination unit 1526 calculates a necessity using a plurality of measurement data, and determines a correction process executed by the correction processing unit 153 based on the calculated necessity.

  For example, a service person of the image forming apparatus 1001 sets the weighting coefficient of each correction process and measurement data used for determination in setting work of the image forming apparatus. The necessity calculation determination unit 1526 selects the set measurement data from the measurement unit 151 (S1305).

  For example, when the measurement data selected in step S1305 is a temperature change amount and the number of image formations, the necessity calculation determination unit 1526 corresponds to the temperature change amount and the number of image formations held in the measurement data holding unit 1525. Each measurement data is acquired (S1306).

Next, the necessity calculation determination unit 1526 includes measurement data P1 and P2 corresponding to the number of image formations acquired from the measurement data holding unit 1525 and measurement data T1 and T2 corresponding to the temperature change amount acquired from the measurement data holding unit 1525. Are used as shown in (Expression 1-2) and (Expression 2-2) below to calculate the necessity of each correction process.
N1 = P1 + T1 (Formula 1-2)
N2 = P2 + T2 (Formula 2-2)
Further, the necessity calculation determination unit 1526 may set the weighting factors WP1, WP2, WT1, and WT2 to each correction process and each measurement data, and use the following (Equation 1-3) and (Equation 2-3). .
N1 = WP1 × P1 + WT1 × T1 (Formula 1-3)
N2 = WP2 * P2 + WT2 * T2 (Formula 2-3)
Furthermore, even if the following (Formula 1-4) and (Formula 2-4) of the combination of adding three or more measurement data using P1, P2 and T1, T2, and elapsed time Time1, Time2 and the necessary degree are calculated Good.
N1 = P1 + T1 + Time1 (Formula 1-4)
N2 = P2 + T2 + Time2 (Formula 2-4)
The necessary degree calculation determination unit 1526 calculates (Equation 1-4) and (Equation 2-4) to each element in the equation in the same manner as (Equation 1-3) and (Equation 2-3). May be set to calculate the necessary degree.

  The necessity calculation determination unit 1526 calculates and calculates a necessity based on a plurality of measurement data, and determines and executes a correction process that should be prioritized based on a plurality of environmental changes and usage situations of the image forming apparatus. Can do.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be changed.

1 CPU
2 ROM
3 RAM
4 I / O ports 5, 5 a, 5 b, 5 c Detecting unit 6 Image forming unit 7 Controller unit 130 Intermediate transfer belt 151 Measuring unit 1511 Image forming number measuring unit 1512 Temperature measuring unit 1513 Number of sheets measuring unit 1514 Time measuring unit 152 Determination unit 1521 Density correction processing flag data holding unit 1522 Color misregistration correction processing flag data holding unit 1523 Execution condition determination unit 1524 Necessity determination unit 1525 Measurement data holding unit 1526 Necessity calculation determination unit 1527 Weight coefficient setting unit 153 Correction processing unit 1531 Density correction processing Unit 1532 color misregistration correction processing unit 30 test patterns 1000 and 1001 image forming apparatus

JP 2001-166553 A JP 2009-169031 A

Claims (6)

An image forming apparatus that performs image formation,
Correction processing means for executing a plurality of correction processes related to the image formation;
Determining means for determining whether or not there are a plurality of correction processes that satisfy the condition to be executed,
The correction processing means includes
When it is determined that there are a plurality of correction processes that satisfy the condition to be executed by the determination unit, the image forming apparatus executes the correction process selected based on the necessity of the plurality of correction processes based on the state of the image forming apparatus .   The degree of necessity includes the number of image formations counted after execution of the previous correction process, the amount of change in temperature after execution of the previous correction process, the number of recording media on which image formation has been performed after execution of the previous correction process, The image forming apparatus according to claim 1, wherein the image forming apparatus is determined based on at least one of measurement data among times elapsed since the execution of the correction process.   The image forming apparatus according to claim 2, further comprising a calculation unit that calculates the degree of necessity by multiplying the measurement data and a weighting factor.   The image forming apparatus according to claim 2, further comprising a calculation unit that calculates the degree of necessity by adding a plurality of the measurement data.   The image forming apparatus according to claim 4, wherein the calculation unit multiplies each of the plurality of measurement data by a weighting coefficient. An image forming apparatus that performs image formation
A correction processing procedure for executing a plurality of correction processes related to the image formation;
A determination procedure for determining whether or not there are a plurality of correction processes that satisfy a condition to be executed,
The correction processing procedure is as follows:
An image forming method for performing a correction process selected based on the necessity of the plurality of correction processes based on the state of the image forming apparatus when it is determined that there are a plurality of correction processes that satisfy the condition to be executed by the determination unit.

Images