JP2010113286A - Control device, image forming apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten image formation wait time, which incurs due to misalignment correction control and density correction control. <P>SOLUTION: When a predetermined density correction execution condition is satisfied, density correction control for correcting density by forming a density detection image is performed. When a predetermined misalignment correction execution condition is satisfied, the misalignment correction is performed by forming a misalignment detection image. When one of a density correction execution condition and a misalignment correction execution condition is satisfied and also a condition predetermined as a permissible range for the other correction execution condition is satisfied, the density detection image and the misalignment detection image are formed to correct the density and the misalignment. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device, an image forming apparatus, and a program.

  In Patent Document 1 below, after forming a detection pattern with the maximum density and correcting the density based on the detection result of the detection pattern, a color shift detection pattern and a plurality of different halftone density density detection patterns are simultaneously formed. An image forming apparatus for detection is disclosed.

  Japanese Patent Laid-Open Publication No. 2003-259259 discloses a method for correcting misregistration by creating a density detection pattern immediately after writing an image, changing an image forming parameter according to the output of the density detection pattern, and creating a misregistration detection pattern. A color image forming apparatus is disclosed.

  Patent Document 3 below discloses an image forming apparatus that switches the processing order of color misregistration correction processing and density correction processing in accordance with the temperature in the apparatus.

In Patent Document 4 below, a trapezoidal detection pattern that is used for both positional deviation detection and density detection is formed on a conveyance belt, and the detection pattern is detected by a plurality of sensors arranged in a direction crossing the conveyance direction of the conveyance belt. A color image forming apparatus that detects deviation and density is disclosed.
JP 2002-014505 A JP 2003-280316 A JP-A-2005-227615 JP 2006-047941 A

  It is an object of the present invention to provide a control device, an image forming apparatus, and a program that can shorten an image formation waiting time that occurs due to the execution of misregistration correction control and density correction control.

  According to a first aspect of the present invention, there is provided a control device for detecting reflected light or transmitted light from an image transferred to the transfer member by an image forming unit that forms a multi-color image and transfers the image to the transfer member. When the image forming unit satisfies a predetermined density correction execution condition, the image forming unit is controlled to form a density detection image for detecting the density of each color image, and the detection is performed. The image forming means so that the density of the image formed by the image forming means is corrected based on the density of each color detected based on the reflected or transmitted light from the density detection image detected by the means. When the density correction control for controlling the color deviation is executed and the predetermined positional deviation correction execution condition is satisfied in the image forming unit, the positional deviation detection image for detecting the positional deviation of the image of each color is formed. The image forming unit is controlled so that the image forming unit is formed based on the amount of misalignment detected based on the reflected light or transmitted light from the misalignment detected image detected by the detecting unit. Misalignment correction control is performed to control the image forming unit so that the image misregistration is corrected, and one correction execution condition of the density correction execution condition and the misregistration correction execution condition is set in the image forming unit. And satisfying a predetermined condition as an allowable range of the other correction execution condition, the image forming unit is controlled so that the density detection image and the displacement detection image are formed, and the detection is performed. The density of the image formed by the image forming means based on the density of each color detected based on the reflected or transmitted light from the density detection image detected by the means The image forming unit is controlled to be corrected, and the image forming unit detects, based on the amount of misalignment detected based on reflected light or transmitted light from the misalignment detected image detected by the detecting unit. And execution means for executing density positional deviation correction control for controlling the image forming means so that the positional deviation of the formed image is corrected.

  According to a second aspect of the present invention, there is provided a control device for detecting reflected light or transmitted light of an image transferred to the transfer target by an image forming unit that forms a multi-color image and transfers the image to the transfer target; When the image forming unit satisfies a predetermined density correction execution condition, the image forming unit is controlled so that a combined detection image for detecting the density and misregistration of each color image is formed; The image is formed so that the density of the image formed by the image forming unit is corrected based on the density of each color detected based on the reflected or transmitted light from the combined detection image detected by the detecting unit. Density correction control for controlling the forming unit is executed, and the amount of positional deviation detected based on the reflected light or transmitted light from the combined detection image detected by the detecting unit is out of a predetermined allowable range. And when the image forming unit satisfies a predetermined misregistration correction execution condition, the image forming unit is configured to form a misregistration detection image for detecting misregistration of each color image. And the positional deviation of the image formed by the image forming means is corrected based on the amount of positional deviation detected based on the reflected or transmitted light from the positional deviation detected image detected by the detecting means. As described above, an execution unit that executes misregistration correction control that controls the image forming unit is provided.

  According to a third aspect of the present invention, there is provided a control device for detecting reflected or transmitted light of an image transferred to the transfer target by an image forming unit that forms a multi-color image and transfers the image to the transfer target; When the image forming unit satisfies a predetermined misregistration correction execution condition, the image forming unit is controlled to form a misregistration detection image for detecting misregistration of each color image; The positional deviation of the image formed by the image forming means is corrected based on the positional deviation amount detected based on the reflected light or transmitted light from the positional deviation detected image detected by the detection means. The first misregistration correction control for controlling the image forming unit is executed, and when the predetermined density correction execution condition is satisfied in the image forming unit, the density and the misregistration of each color image are detected. Based on the density for each color detected based on the reflected light or transmitted light from the combined detection image detected by the detection unit, the image forming unit is controlled so that a combined combined detection image is formed, First density correction control is performed to control the image forming unit so that the density of the image formed by the image forming unit is corrected, and reflected light or transmission from the combined detection image detected by the detection unit When the amount of misregistration detected based on the light falls outside a predetermined allowable range, the misregistration of the image formed by the image forming unit is determined based on the detected misregistration amount of the combined detection image. The image forming unit is controlled so as to be corrected, and the next execution time of the first misregistration correction control is adjusted to be later than the next execution time determined by the misregistration correction execution condition. Includes first execution means for executing a second positional deviation correction control that, the.

  According to a fourth aspect of the present invention, when the density correction execution condition is satisfied in the image forming means, a density detection image for detecting the density of each color image is formed in the control device according to the third aspect. The image forming unit controls the image forming unit, and the image forming unit forms an image based on the density of each color detected based on the reflected or transmitted light from the density detection image detected by the detecting unit. Second density correction control is performed to control the image forming unit so that the density of the image is corrected. When the image forming unit satisfies the position shift correction execution condition, the first position shift correction control is performed. Second execution means to be executed, selection means for selecting an operation mode of the image forming means, and execution means to be operated according to a selection result of the selection means, the first execution means and the second execution And switching means for switching to either one of stages, in which the further provided.

  According to a fifth aspect of the present invention, in the control device according to the third or fourth aspect, the first execution unit controls the image forming unit so that the positional deviation is corrected by the second positional deviation correction control. In addition, control is performed so that the correction is performed with a correction amount smaller than the correction amount when the image forming unit is controlled so that the positional shift is corrected by the first positional shift correction control.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus comprising: an image forming unit that forms an image of a plurality of colors and transfers the image to a transfer target; and the control device according to any one of the first to fifth aspects. It is.

  According to the seventh aspect of the present invention, when a predetermined density correction execution condition is satisfied in an image forming means for forming a multi-color image and transferring it to a transfer medium on a computer, the density of the image of each color is detected. From the density detection image detected by the detection means for controlling the image forming means so as to form a density detection image for detecting the reflected light or transmitted light from the image transferred to the transfer target. Based on the density for each color detected based on the reflected light or transmitted light, density correction control is performed to control the image forming unit so that the density of the image formed by the image forming unit is corrected, When the image forming unit satisfies a predetermined misregistration correction execution condition, the image forming unit forms a misregistration detection image for detecting misregistration of each color image. And the positional deviation of the image formed by the image forming means is corrected based on the amount of positional deviation detected based on the reflected or transmitted light from the positional deviation detected image detected by the detecting means. In this way, the positional deviation correction control for controlling the image forming unit is executed so that one of the density correction execution condition and the positional deviation correction execution condition is satisfied in the image forming unit and the other correction execution condition is satisfied. When the predetermined condition as an allowable range is satisfied, the image forming unit is controlled so that the density detection image and the displacement detection image are formed, and the density detection image detected by the detection unit The image shape so that the density of the image formed by the image forming means is corrected based on the density of each color detected based on the reflected light or transmitted light from And a position shift of an image formed by the image forming means based on a position shift amount detected based on reflected light or transmitted light from the position shift detected image detected by the detection means. This is a program for executing density positional deviation correction control for controlling the image forming means so as to be corrected.

  According to the eighth aspect of the present invention, the density and position of the image of each color are satisfied when a predetermined density correction execution condition is satisfied in the image forming means for forming the image of a plurality of colors on the computer and transferring the image to the transfer target. The dual-purpose detection detected by the detection means for controlling the image forming means so as to form a dual-purpose detection image for detecting deviation and detecting reflected or transmitted light of the image transferred to the transfer target. Executes density correction control for controlling the image forming unit so that the density of the image formed by the image forming unit is corrected based on the density of each color detected based on reflected light or transmitted light from the image. If the amount of positional deviation detected based on the reflected or transmitted light from the combined detection image detected by the detection means is outside a predetermined allowable range, and the image forming means When the predetermined misregistration correction execution condition is satisfied, the image forming unit is controlled so that a misregistration detection image for detecting the misregistration of each color image is formed. The image forming unit is configured so that the positional deviation of the image formed by the image forming unit is corrected based on the amount of positional deviation detected based on reflected light or transmitted light from the detected positional deviation detected image. This is a program for executing positional deviation correction control to be controlled.

  According to the ninth aspect of the present invention, when an image forming unit that forms a multi-color image and transfers it to a transfer medium satisfies a predetermined misalignment correction execution condition, the misalignment of the image of each color is achieved. The misregistration detected by the sensing means for controlling the image forming means so as to form a misregistration detection image for detecting an image and detecting reflected light or transmitted light of the image transferred to the transfer target. A first misregistration for controlling the image forming unit so that the misregistration of the image formed by the image forming unit is corrected based on a misregistration amount detected based on reflected light or transmitted light from the detected image. When the correction control is executed and a predetermined density correction execution condition is satisfied in the image forming unit, a combined detection image for detecting the density and positional deviation of each color image is formed. The image forming means controls the image forming means, and based on the density of each color detected based on the reflected or transmitted light from the combined detection image detected by the detecting means, the image forming means A density correction control for controlling the image forming unit so as to correct the density is executed, and a positional deviation amount detected based on reflected light or transmitted light from the combined detection image detected by the detection unit is determined in advance. When the image forming unit is out of the allowable range, the image forming unit is controlled so that the positional deviation of the image formed by the image forming unit is corrected based on the detected positional deviation amount of the combined detection image. At the same time, the second misalignment correction control is executed to adjust the next execution timing of the first misalignment correction control to be later than the next execution timing determined by the misalignment correction execution condition. It is because of the program.

  According to the first aspect of the present invention, it is possible to reduce the image formation waiting time generated by the execution of the positional deviation correction control and the density correction control.

  According to the second aspect of the present invention, it is possible to reduce the image formation waiting time generated by the execution of the positional deviation correction control and the density correction control.

  According to the third aspect of the present invention, it is possible to reduce the image formation waiting time that occurs due to the execution of the positional deviation correction control and the density correction control.

  According to the fourth aspect of the present invention, it is possible to reduce the image formation waiting time that occurs due to the execution of the positional deviation correction control and the density correction control.

  According to the invention of claim 5, it is possible to prevent overcorrection.

  According to the sixth aspect of the present invention, it is possible to reduce the image formation waiting time that occurs due to the execution of the positional deviation correction control and the density correction control.

  According to the seventh aspect of the present invention, it is possible to reduce the image formation waiting time that occurs due to the execution of the positional deviation correction control and the density correction control.

  According to the eighth aspect of the present invention, it is possible to reduce the image formation waiting time generated by the execution of the positional deviation correction control and the density correction control.

  According to the ninth aspect of the present invention, it is possible to reduce the image formation waiting time generated by the execution of the positional deviation correction control and the density correction control.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a block diagram illustrating an example of the configuration of the image forming apparatus 20 according to the present embodiment.

  The image forming apparatus 20 includes a main control unit 22, a UI (user interface) 24, an image formation control unit 26, an image forming unit 28, and a detection unit 29.

  The main control unit 22 receives image information from the host computer and controls the entire operation of the image forming apparatus 20 so that image formation is performed based on the received image information.

  FIG. 2 is a block diagram showing the configuration of the main control unit 22.

  The main control unit 22 includes a CPU (Central Processing Unit) 30, a RAM (Random Access Memory) 32, a ROM (Read Only Memory) 34, a UI controller 36, an HDD (Hard Disk Drive) 38, an interface 40, and a communication interface 42. , They are connected to each other via a bus 44.

  The UI 24 is connected to the UI controller 36. The UI 24 is composed of, for example, a touch panel display and the like, and functions as a display unit that displays information such as images and various messages in accordance with control signals input from the CPU 30, and an arbitrary position on the image displayed on the UI 24. It also has a function as an input unit for inputting instructions by designating the user. Note that the UI 24 is not limited to a touch panel display, and for example, a display unit such as a liquid crystal display and an input unit such as an operation button operated by an operator may be individually equipped. .

  Various information such as image information and a program executed by the CPU 30 is stored in the HDD 38.

  An image formation control unit 26 and a detection unit 29 are connected to the interface 40. The CPU 30 transmits image information and various control signals to the image formation control unit 26 via the interface 40, and receives a signal indicating a detection result from the detection unit 29. The detection unit 29 includes the optical sensor 10 and the signal processing circuit 16. The detailed configuration and operation of the detection unit 29 will be described later.

  The main control unit 22 is connected to a host computer via a communication interface 42. The main control unit 22 receives image information and the like from the host computer via the communication interface 42.

  The CPU 30 executes a program stored in the ROM 34, the HDD 38, or the like. The RAM 32 is used not only as a memory for temporarily storing various data such as image information input from the host computer via the communication interface 42, but also as a work memory at the time of program execution.

  The recording medium on which the program executed by the CPU 30 is stored is not limited to the ROM 34, the HDD 38, or the like, but a portable recording medium such as a CD-ROM, an FD (flexible disk), a DVD disk, a magneto-optical disk, and an IC card. It may be. In this case, the image forming apparatus 20 is configured by providing a drive and a connection port for reading program data from the portable recording medium. Further, the recording medium on which the program executed by the CPU 30 is stored may be a storage device such as an HDD provided outside the image forming apparatus 20. Furthermore, it may be a database connected via a network, or another computer system and its database, or a transmission medium such as a carrier wave on a telecommunication line.

  Although not shown, the image formation control unit 26 includes a microcomputer including a CPU, a RAM, and a ROM, a buffer that temporarily stores image information, and an image processing circuit that performs image processing. The image forming operation of the image forming unit 28 is controlled based on the image information and the control signal input from the main control unit 22.

  Specifically, the image formation control unit 26 generates image information for each color of yellow Y, magenta M, cyan C, and black K from the image information input from the main control unit 22, and the image formation unit 28 will be described later. Output to the laser output unit (ROS) 3. The image formation control unit 26 also controls a transport operation for transporting a recording sheet on which an image is formed by the image forming unit 28 by transmitting a control signal.

  Although not shown, image information obtained by reading an image of a document from the image reading unit is also input to the image forming control unit 26. The image formation control unit 26 also processes this image information as described above and outputs it to the ROS 3.

  The image forming unit 28 forms an image on a recording sheet based on the image information and the control signal input from the image formation control unit 26.

  FIG. 3 is a configuration diagram of the image forming unit 28. The image forming unit 28 charges the surface of the photoreceptor with a contact charger, forms an electrostatic latent image by light irradiation, and develops the electrostatic latent image with toner using a yellow Y, magenta M, This is an image forming unit of a tandem type color electrophotographic system provided for each color of cyan C and black K.

  The image forming unit 28 includes four photoconductors 1Y, 1M, 1C, and 1K that rotate in the direction of arrow A in the figure, and a contact charger 2Y that charges the surface of each photoconductor by applying a charging bias. ROS (laser output unit) 3Y that exposes the surface of each charged photoconductor with 2M, 2C, and 2K with light modulated based on image information of each color and forms an electrostatic latent image on each photoconductor 3M, 3C, and 3K, and developing rolls 46Y, 46M, 46C, and 46K for holding the respective color developers, and electrostatic charges on the photosensitive members by applying a developing bias to the developing rolls 46Y, 46M, 46C, and 46K Developing units 4Y, 4M, 4C, and 4K that develop the latent image with each color developer to form a toner image on the photoreceptor, and a primary transfer unit 5Y that transfers each color toner image on the photoreceptor to the intermediate transfer belt 6. 5M, 5C, 5K and A secondary transfer device 7 that transfers the toner image on the intermediate transfer belt 6 to the recording paper, a fixing device 9 that fixes the toner image transferred to the recording paper, a paper storage portion T that stores the recording paper, A cleaner (not shown) for cleaning the surface of the photosensitive member, a static eliminator (not shown) for removing residual charges on the surface of each photosensitive member, and a belt cleaner 8 for cleaning the surface of the intermediate transfer belt. Yes.

  Although not shown, a temperature sensor that detects the temperature inside the image forming unit 28 is also provided in the image forming unit 28. Information on the temperature detected by the temperature sensor is output to the CPU 30.

  Hereinafter, when the photoreceptors 1Y, 1M, 1C, and 1K are described without particular distinction, the suffix at the end of the reference numerals is omitted and referred to as the photoreceptor 1. Also, contact chargers 2Y, 2M, 2C, 2K, ROS3Y, 3M, 3C, 3K, developing rolls 46Y, 46M, 46C, 46K, developing devices 4Y, 4M, 4C, 4K, and primary transfer devices 5Y, 5M, 5C. Similarly, in the case of 5K, in the case where the components of each of YMCK are not particularly distinguished, the suffix at the end of the code is omitted.

  Here, an image forming operation in the image forming apparatus 20 of the present embodiment will be briefly described. Driving is started by a control signal from the CPU 30, and the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K are charged to a predetermined charging potential by applying a charging bias to the contact chargers 2Y, 2M, 2C, and 2K from a power source. . When the surfaces of the photoconductors 1Y, 1M, 1C, and 1K charged by the contact chargers 2Y, 2M, 2C, and 2K reach the positions of the color developing devices 4Y, 4M, 4C, and 4K, the color developing devices 4Y, 4M, and 4C, respectively. A developing bias is applied to 4K from a power source so as to have a predetermined developing potential.

  On the other hand, after image information read from an original by an image reading unit (not shown) or image information created by an external host computer or the like is decomposed into image information for each color by the image formation control unit 26, Input to ROS3Y, 3M, 3C, 3K. Each of the ROS 3Y, 3M, 3C, and 3K is provided with a drive circuit and a laser diode. The drive circuit provided in each ROS 3Y, 3M, 3C, and 3K is provided with a laser diode according to input image information. A drive current is supplied, whereby light is emitted from the laser diode. The emitted light is applied to the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K charged by the contact chargers 2Y, 2M, 2C, and 2K. When light is scanned on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K, electrostatic latent images corresponding to input image information are formed on the photoreceptors 1Y, 1M, 1C, and 1K, respectively. Subsequently, the electrostatic latent images on the photoconductors are developed with toner by the color developing devices 4Y, 4M, 4C, and 4K, and toner images are formed on the photoconductors. The toner images formed on the photoreceptors 1Y, 1M, 1C, and 1K are transferred to the intermediate transfer belt 6 by the primary transfer units 5Y, 5M, 5C, and 5K. In each of the photoreceptors 1Y, 1M, 1C, and 1K, after the transfer of the toner image to the intermediate transfer belt 6 is completed, the remaining toner and other adhering matter adhered to the surface are cleaned by the cleaner, and the residual charge is removed by the static eliminator. The

  Next, the toner images of the respective colors on the intermediate transfer belt 6 are transferred onto the recording paper sent from the paper storage portion T by the secondary transfer device 7 and then transferred onto the recording paper by the fixing device 9. The toner image transferred to is fixed and a desired image is obtained. After the transfer of the toner image onto the recording paper, the intermediate transfer belt 6 is cleaned of adhering matters such as residual toner adhering to the surface by the belt cleaner 8 and is transferred to the contact chargers 2Y, 2M, 2C and 2K. The application of the charging bias is stopped, the application of the developing bias to each of the color developing devices 4Y, 4M, 4C, and 4K is stopped, and further, the driving of the image forming unit 28 is stopped, thereby completing one image forming operation. Hereinafter, image formation may be referred to as printing.

  In an electrophotographic color image forming apparatus, image fluctuations such as positional deviation and density fluctuation of each color toner image occur due to environmental conditions such as temperature and humidity and changes with time. Correction control is performed. In each correction control, a predetermined detection image is formed on the intermediate transfer belt 6 and is detected by the optical sensor 10. The detection result is transmitted to the CPU 30 via the signal processing circuit 16. In accordance with the detection result, the CPU 30 performs positional deviation correction (for example, correction of the light irradiation timing of the ROS 3) and density correction (for example, correction of the driving current supplied from the laser diode of the ROS 3).

  Here, the optical sensor 10 will be described in detail with reference to FIG.

  FIG. 4A is a diagram illustrating an arrangement example of the optical sensor 10, and FIG. 4B is a schematic configuration diagram of the optical sensor 10. Two optical sensors 10 are provided at positions facing the transfer surface of the intermediate transfer belt 6. The optical sensor 10 includes a light emitting unit 12 and a light receiving unit 14.

  The light emitting unit 12 and the light receiving unit 14 are arranged in a positional relationship that can receive reflected light by light applied to the detected image.

  When the light emitted from the light emitting unit 12 is applied to the detection image formed on the intermediate transfer body belt 6, the reflected light from the detection image is received by the light receiving unit 14. The light receiving unit 14 includes a photodiode, and outputs an analog output signal corresponding to the amount of received light (the density of the image). The analog output signal is subjected to necessary signal processing by the signal processing circuit 16 and then output to the CPU 30. The signal processing of the signal processing circuit 16 will be described later.

  In this embodiment, the optical sensor 10 that receives reflected light from an image has been described as an example. However, when the intermediate transfer belt 6 is made of a material that transmits light, the image is displayed. An optical sensor that receives the transmitted light may be used. In this case, the light receiving unit 14 is disposed on the back side of the intermediate transfer belt 6.

  Here, the types of detected images will be described. The detection image P includes two types of images, a position shift detection image P1 and a density detection image P2. FIG. 5A is a diagram showing an example of the positional deviation detection image P1, and FIG. 5B is a diagram showing an example of the density detection image P2. In the drawing, the first direction indicates the rotation direction of the photosensitive member 1 and the intermediate transfer belt 6, and the second direction indicates the scanning direction of light emitted from the ROS 3.

  In this embodiment, as the misregistration detection image P1, an I-shaped pattern image and a V-shaped pattern image having a halftone dot area ratio (density) of 100% are determined in advance for each color. In FIG. 5A, images arranged in the order of K, C, M, and Y) are formed. As the density detection image P2, here, five rectangular pattern images having a dot area ratio of 100%, 70%, 50%, 30%, and 10% are predetermined for each color. It shall be formed at intervals. Note that the halftone dot area ratios of the misregistration detection image P1 and the density detection image P2 are not limited to these. FIG. 5B illustrates only the density detection image P2 for K color.

  FIG. 6 shows the positional relationship between the V-shaped misalignment detection image P1 formed on the intermediate transfer body belt 6 and the visual field region R of the optical sensor 10 on the intermediate transfer body belt 6, and also from the optical sensor 10. The output sensor output signal and the pulse signal output from the signal processing circuit 16 are shown over time.

  The lower graph (A) shows the waveform of the sensor output signal corresponding to the position of the visual field region R of the optical sensor 10.

  The misregistration detection image P <b> 1 primarily transferred onto the intermediate transfer body belt 6 passes through the front surface of the optical sensor 10 as the intermediate transfer body belt 6 rotates, and crosses the visual field region R of the optical sensor 10. When the misalignment detection image P1 moves together with the intermediate transfer belt 6 and the visual field region R of the optical sensor 10 reaches the end of one side m1 of the misalignment detection image P1, the sensor output signal starts to change. When the displacement detection image P1 further moves, the area of the displacement detection image P1 included in the visual field region R increases, so that the sensor output signal gradually increases, and the position where the visual field region R is covered by the displacement detection image P1. In, the sensor output signal becomes maximum. After this position, the overlapping area between the visual field region R and the positional deviation detection image P1 decreases, so that the sensor output signal gradually decreases. Further, since the misregistration detection image P1 is V-shaped, the next side m2 crosses the visual field region R of the optical sensor 10 as the intermediate transfer belt 6 rotates. Thereby, the sensor output signal rises again, and after the sensor output signal reaches the maximum, it gradually falls.

  A sensor output signal output from the optical sensor 10 is input to the signal processing circuit 16. The signal processing circuit 16 compares the input sensor output signal with a predetermined threshold value and outputs a pulse signal. The rising edge of the pulse signal corresponds to the edge position of m1 and the edge position of m2. The I-shaped misalignment detection image P1 is also detected in the same manner as described above, and a pulse signal is output.

  Here, the example in which the sensor output signal and the threshold value are compared to output the pulse signal has been described. However, as shown in FIG. 7, the maximum position of the input sensor output signal is detected, and the maximum position is detected. In addition, a pulse signal may be output.

  By detecting the I-shaped displacement detection image P1 for each color, the distance of the rising edge of the output pulse signal is measured, and the displacement in the first direction is detected. Further, the distance of the rising edge of the output pulse signal is measured by detecting the V-shaped misregistration detection image P1 for each color, and the misregistration in the second direction is detected.

  Hereinafter, a pulse signal generated from an analog output signal obtained by detecting the displacement detection image P1 is referred to as a displacement detection signal.

  FIG. 8 shows the positional relationship between the density detection image P2 formed on the intermediate transfer body belt 6 and the visual field region R of the optical sensor 10 on the intermediate transfer body belt 6, and the sensor output output from the optical sensor 10. It is the figure which showed the signal along time passage.

  The density detection image P <b> 2 primarily transferred onto the intermediate transfer body belt 6 passes through the front surface of the optical sensor 10 as the intermediate transfer body belt 6 rotates and crosses the visual field region R of the optical sensor 10. As a result, a sensor output signal as shown in the lower part of FIG. The maximum level d of the sensor output signal output from the optical sensor 10 indicates the density of the density detection image P2. The signal processing circuit 16 generates a digital density detection signal indicating the maximum level d and outputs it to the CPU 30.

  Next, misregistration correction control performed in the image forming apparatus 20 will be described.

  FIG. 9 is a flowchart showing the flow of misalignment correction control performed by the CPU 30.

  In step 100, the CPU 30 supplies image information for forming the misalignment detection image P <b> 1 to the image formation control unit 26. As a result, the image forming unit 28 forms the misalignment detection image P1 on the intermediate transfer belt 6.

  In step 102, the CPU 30 detects the amount of positional deviation. Specifically, as described above, the positional deviation detection image P <b> 1 is detected by the optical sensor 10, and a positional deviation detection signal indicating the detection result is output from the signal processing circuit 16. The CPU 30 obtains a positional deviation amount between a predetermined reference color (for example, C color) and another color based on the positional deviation detection signal output from the signal processing circuit 16.

  In step 104, the CPU 30 corrects the positional deviation of the image forming position based on the positional deviation amount of the positional deviation detection image P1. Specifically, the irradiation timing of the light to the photoreceptor 1 in the first direction and the second direction by the ROS 3 is set.

  Next, density correction control performed in the image forming apparatus 20 will be described.

  FIG. 10 is a flowchart showing the flow of density correction control performed by the CPU 30.

  In step 100, the CPU 30 supplies image information for forming the density detection image P2 to the image formation controller 26. Accordingly, the image forming unit 28 forms the density detection image P2 on the intermediate transfer body belt 6.

  In step 102, the CPU 30 detects the density of the density detection image P2. Specifically, as described above, the density detection image P <b> 2 is detected by the optical sensor 10, and a density detection signal indicating the detection result is output from the signal processing circuit 16. The CPU 30 obtains the density of the density detection image P2 from the density detection signal output from the signal processing circuit 16.

  In step 104, the CPU 30 performs density correction based on the density of the density detection image P2. Specifically, the CPU 30 obtains a difference between the detected density and a predetermined density target value, and from the obtained difference. Also, change information is transmitted to the image formation control unit 26 so that the image formation conditions such as the exposure amount of ROS3 (drive current for driving the laser diode of ROS3), the development bias, the gradation correction curve, and the density correction table are changed. To do. Thereby, the setting of the image forming condition of the image forming unit 28 is changed.

  In many cases, the image position deviation is caused by an increase in the internal temperature of the apparatus, and the density reduction is caused by the number of printed sheets. As described above, since the factors are different from each other, conventionally, the density correction control and the positional deviation correction control are individually executed by using individually set execution conditions as triggers. In the present embodiment, each correction is performed. Control is executed as follows.

  FIG. 11 is a flowchart showing the flow of correction control execution processing according to the present embodiment.

  In step 200, the CPU 30 determines whether or not a predetermined misalignment correction execution condition for performing misalignment correction control is satisfied. In the present embodiment, an execution condition is set as a condition for executing the position shift correction, “an increase of t ° C. from the temperature detected when the previous position shift correction control is executed”. For example, when t = 2 and the temperature detected when the previous misregistration correction control is executed is 12 ° C., the next misregistration correction control uses the temperature detected by the temperature sensor as 14 ° C. It is executed at the timing.

  If the temperature detected by the temperature sensor does not satisfy the execution condition, a negative determination is made in step 200 and the process proceeds to step 202.

  In step 202, the CPU 30 determines whether or not a predetermined density correction execution condition for executing density correction control is satisfied. In the present embodiment, an execution condition “x printed after executing previous density correction control” is set as the density correction execution condition. For example, when x = 100 and the cumulative pudding and the number of sheets when the previous density correction control is executed are 200 sheets, the next density correction control is executed at the timing when the cumulative pudding and the number of sheets become 300 sheets. Is done.

  If the number of prints after the previous density correction control of the image forming unit 28 has not reached x, the CPU 30 makes a negative determination in step 202 and returns to step 200.

  On the other hand, if an affirmative determination is made in step 200, the process proceeds to step 204. In step 204, the CPU 30 determines whether or not a condition predetermined as an allowable range of the density correction execution condition is satisfied. In the present embodiment, the following expressions are set in advance as conditions for the allowable range.

  x−α ≦ β (1)

  Here, α is the number of prints from the previous execution of density correction control to the present, and β is a predetermined allowable value.

  For example, if x is 100 sheets, the number of printed sheets α from the previous execution of density correction control to 95 is 95, and the allowable value β is 5, 100−95 = 5. 1) is satisfied.

  Accordingly, in this case, an affirmative determination is made in step 204 and the process proceeds to step 206.

  In step 206, the CPU 30 executes misregistration correction control and density correction control. Since the positional deviation correction control is as described with reference to FIG. 9 and the density correction control is as described with reference to FIG. 10, detailed description is omitted here. Here, the density correction control may be performed first, or the positional deviation correction control may be performed first. In step 206, the density correction control and the positional deviation correction control may be performed individually and continuously. However, after the positional deviation detection image P1 and the density detection image P2 are continuously formed, these positional deviations are performed. The positional deviation amount of the detected image P1 and the density of the density detection image P2 may be detected, and the positional deviation correction may be performed based on the detected positional deviation amount and the density correction may be performed based on the detected density.

  After step 206, the process returns to step 200.

  If affirmative determination is made in step 204 before α reaches x, the execution timing of the density correction control from the next time also shifts accordingly. For example, when x = 100, correction control is normally executed at the timing when the cumulative number of printed sheets is 100, 200, 300,..., But the cumulative number of printed sheets is 95. If the determination in step 204 is affirmative and the density correction control is executed, based on the density correction execution condition, the timing when the cumulative number of prints will be 195, 295, 395,. Thus, the density correction control is executed.

  On the other hand, if a negative determination is made in step 204, the process proceeds to step 210. In step 210, the CPU 30 executes only misalignment correction control, and then returns to step 200.

  If a negative determination is made in step 200 and an affirmative determination is made in step 202, the process proceeds to step 208. In step 208, the CPU 30 executes density correction control, and then returns to step 200.

  Note that a condition “when the image forming apparatus 20 is activated” may be additionally set as the positional deviation correction control and the density correction execution condition.

  FIG. 12A is a diagram illustrating an example of execution timing of misalignment correction control when misalignment correction control is performed every 2 ° C.

  FIG. 12B is a diagram illustrating an example of execution timing of density correction control when density correction control is performed for every 100 printed sheets.

  FIG. 12C is a diagram showing the execution timing of the positional deviation correction control in FIG. 12A and the execution timing of the density correction control in FIG. If the correction control of the misregistration correction and the density correction is individually executed using individual execution conditions as triggers without performing the correction control execution process shown in FIG. The correction control is executed 13 times during the period.

  13A is the same diagram as FIG. 12C, and FIG. 13B is a diagram showing the execution timing of the correction control when the correction control execution process shown in FIG. 11 is performed. In FIGS. 13A and 13B, Δ indicates the timing when the positional deviation correction control and the density correction control are collectively executed in step 206 described above.

  In the period of the cumulative number of printed sheets of 0 to 500, the sum of the timing at which the positional deviation correction control is executed alone, the timing at which the density correction control is executed alone, and the timing at which the two correction controls are executed together is shown in FIG. In B), the number is 10 times, and when the correction control execution process of FIG. 11 is performed, the number of executions of the correction control is reduced. It should be noted that performing both the positional deviation correction correction control and the density correction control at a time is shortened in terms of time compared to performing individually at different timings under different conditions.

  Note that the correction control execution process shown in FIG. 14 may be performed instead of the correction control execution process shown in FIG.

  In step 240, the CPU 30 determines whether or not a predetermined density correction execution condition is satisfied. Here, it is assumed that an execution condition “x printed after executing previous density correction control” is set as the density correction execution condition.

  If the number of prints since the previous density correction control was performed is less than x, a negative determination is made in step 240 and the process proceeds to step 242.

  In step 242, the CPU 30 determines whether or not a predetermined misalignment correction execution condition is satisfied. Here, it is assumed that an execution condition that “the temperature has been increased by t ° C. from the temperature detected by the temperature sensor when the previous position deviation correction control was executed” is set as the position deviation correction execution condition.

  If the temperature detected by the temperature sensor does not satisfy the execution condition, a negative determination is made in step 242 and the process returns to step 240.

  On the other hand, if an affirmative determination is made in step 240, the process proceeds to step 244. In step 244, the CPU 30 determines whether or not a condition predetermined as an allowable range of the positional deviation correction execution condition is satisfied. Here, it is assumed that the following equation (2) is set in advance as a condition for the allowable range.

  t−γ ≦ ω (2)

  Here, γ is a temperature difference between the temperature when the previous positional deviation correction control was executed and the current temperature, and ω is a predetermined allowable value.

  For example, if t = 2 ° C., the temperature difference γ between the temperature when the previous positional deviation correction control was executed and the current temperature is 1.5 ° C. and the allowable value is 0.5 ° C., 2 −1.5 = 0.5, which satisfies the above (2).

  Therefore, in this case, step 244 is affirmed and the process proceeds to step 246.

  In step 246, the CPU 30 executes misalignment correction control and density correction control as in step 206 described above. After step 246, the process returns to step 240.

  If affirmative determination is made in step 244 before γ reaches 2 ° C., the execution timing of the subsequent positional deviation correction control is shifted accordingly. For example, if t = 2 ° C and the startup time is 0 ° C, the misalignment correction control is normally executed at the timing when the temperature becomes 0 ° C, 2 ° C, 4 ° C, 6 ° C, etc. However, if the step 204 is affirmatively determined when γ is 1.5 ° C. and the misregistration correction control is executed, assuming that the temperature at this time is 3.5 ° C., the misregistration described above is performed. Based on the correction execution condition, the positional deviation correction control is executed at the timing when the temperature becomes 5.5 ° C., 7.5 ° C.,.

  If a negative determination is made in step 244, the process proceeds to step 250. In step 250, the CPU 30 executes only the density correction control and then returns to step 240.

  On the other hand, if a negative determination is made in step 240 and a positive determination is made in step 242, the process proceeds to step 248. In step 248, the CPU 30 executes misalignment correction control and returns to step 240.

  In the present embodiment, with reference to FIG. 11, it is determined whether or not the allowable range of the positional deviation correction condition is satisfied when the density correction execution condition is viewed. With reference to FIG. Although an example in which it is determined whether or not the allowable range of the density correction condition is satisfied when the shift correction execution condition is viewed has been described, the present invention is not limited to this. For example, it is determined whether or not an allowable range condition of the positional deviation correction condition is satisfied when the density correction execution condition is viewed, and the allowable range condition of the density correction condition is satisfied when the positional shift correction execution condition is viewed. It may be determined whether or not.

  [Second Embodiment]

  In the above embodiment, an example in which the misregistration detection image P1 is formed and the misregistration correction control is performed, and the density detection image P2 is formed and the density correction control is performed has been described. An example in which simple correction control is performed using P4 will be described.

  Note that the apparatus configuration of the image forming apparatus 20 of the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  As shown in FIG. 5C, the combined detection image P4 is a detection image capable of detecting both density and positional deviation, and is a pattern image n1 for each color corresponding to the rectangular pattern of the density detection image P2. Between the pattern area n2 having a predetermined halftone dot area ratio z% in which a pattern image n2 having an edge with a predetermined inclination angle θ (0 <θ <90) with respect to the first direction is inserted. As shown in FIG. 5B, the image includes a displacement detection image P3 and a density detection image P2 made up of a plurality of halftone dot area ratio rectangular patterns excluding the halftone dot area ratio z%.

  As described in the first embodiment, the density of the combined detection image P4 is detected from the maximum level d of the sensor output signal. Further, the detection of the positional deviation of the combined detection image P4 is detected as shown in FIG.

  FIG. 15A shows the density / position shift detection image P3 of the dual-purpose detection image P4 formed on the intermediate transfer belt 6 and the center of the visual field region R of the optical sensor 10 when no position shift occurs. FIG. 6 is a diagram showing the positional relationship with the rotation of the intermediate transfer belt 6 with thick arrows.

  As described in the first embodiment, the edge positions of the pattern images n1 and n2 are detected by the pulse signal. The distance da of the edge position of the pattern image n1 for each color represents the amount of positional deviation in the first direction, and the distance db of the edge position of the pattern image n2 for each color represents the amount of positional deviation in the first direction + second direction. In order to indicate the positional deviation amount, the CPU 30 obtains the distances da and db and detects the positional deviation amount.

  For example, when only a positional deviation in the first direction occurs in the C color pattern image, as shown in FIG. 15B, the distance da and the distance db vary by the positional deviation amount in the first direction. .

  Further, in the case of the C color pattern image, when the positional deviation in the second direction occurs together with the positional deviation in the first direction, as shown in FIG. 15C, the distance da is equal to the first direction. However, the distance db varies by an amount obtained by adding the influence of the positional deviation in the second direction to the positional deviation amount in the first direction. The positional deviation amount h in the second direction can be obtained by the following equation, where v is the fluctuation amount of the distance da (= the positional deviation amount in the first direction) and u is the fluctuation amount of the distance db.

  h = (u−v) tan θ (3)

  Since the combined detection image P4 includes the pattern image n1 of the density detection image P2, the density detection is performed with the same accuracy as that of the density detection image P2. Since the accuracy as high as (the misalignment detection image P1) cannot be obtained, hereinafter, obtaining the misalignment amount using the combined detection image P4 as described above is referred to as simple misalignment detection.

  FIG. 16 is a flowchart showing a flow of correction control execution processing according to the present embodiment.

  In step 300, the CPU 30 determines whether or not a predetermined density correction execution condition is satisfied. Here, it is assumed that the execution condition “x printed after executing previous density correction control” is set as the density correction execution condition.

  If the number of prints since the previous density correction control was executed is less than x, a negative determination is made in step 300 and the process proceeds to step 302.

  In step 302, the CPU 30 determines whether or not a predetermined misalignment correction execution condition is satisfied. Here, it is assumed that an execution condition that “the temperature has been increased by t ° C. from the temperature detected by the temperature sensor when the previous position deviation correction control was executed” is set as the position deviation correction execution condition.

  If the temperature detected by the temperature sensor does not satisfy the execution condition, a negative determination is made in step 302 and the process returns to step 300.

  On the other hand, if an affirmative determination is made in step 300, the process proceeds to step 304. In step 304, the CPU 30 supplies image information for forming the combined detection image P4 to the image formation control unit 26. As a result, the image forming unit 28 forms the combined detection image P4 on the intermediate transfer belt 6.

  In step 306, the CPU 30 detects the density of the combined detection image P4.

  In step 308, the CPU 30 performs density correction based on the density of the combined detection image P4.

  In step 310, the CPU 30 performs simple positional deviation amount detection. The method for detecting the simple positional deviation amount is as described above.

  In step 312, the CPU 30 determines whether or not the positional deviation amounts in the first and second directions detected by the simple positional deviation amount detection are within a predetermined allowable range dp. Note that the allowable range of the positional deviation amount in the first direction may be different from the allowable range of the positional deviation amount in the second direction.

  If an affirmative determination is made in step 312, the process returns to step 300. When a negative determination is made at step 312 and when an affirmative determination is made at step 302, the process proceeds to step 314.

  In step 314 to step 318, the CPU 30 performs misalignment correction control. This misregistration correction control is the same as the misregistration correction control described with reference to FIG. Thereafter, the process returns to step 300.

  [Third Embodiment]

  In the second embodiment, the detection result of the simple misregistration amount detection is used to determine whether or not to execute misregistration correction control using the misregistration detection image P1 dedicated to misregistration detection. Alternatively, the misalignment correction may be performed using the detection result of the simple misalignment detection as it is.

  Note that the apparatus configuration of the image forming apparatus 20 of the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  FIG. 17 is a flowchart showing the flow of correction control execution processing according to the present embodiment.

  In step 340, the CPU 30 determines whether or not a predetermined density correction execution condition is satisfied. Here, it is assumed that the execution condition “x printed after executing previous density correction control” is set as the density correction execution condition.

  If the number of prints since the previous density correction control was executed is less than x, a negative determination is made in step 340 and the process proceeds to step 352.

  In step 352, the CPU 30 determines whether or not a predetermined positional deviation correction execution condition is satisfied. Here, it is assumed that an execution condition that “the temperature has been increased by t ° C. from the temperature detected by the temperature sensor when the previous position deviation correction control was executed” is set as the position deviation correction execution condition.

  If the temperature detected by the temperature sensor does not satisfy the execution condition, a negative determination is made in step 354 and the process returns to step 340.

  On the other hand, if an affirmative determination is made in step 352, the process proceeds to step 354. In step 354 to step 358, the CPU 30 performs misalignment correction control. This misregistration correction control is the same as the misregistration correction control described with reference to FIG. After the positional deviation correction control, the process returns to step 352.

  On the other hand, if an affirmative determination is made in step 340, the process proceeds to step 342. The processing from step 342 to step 348 is the same as step 304 to 310 in FIG.

  In step 350, the CPU 30 determines whether or not the positional deviation amounts in the first and second directions obtained in step 348 are within the allowable range dp. If an affirmative determination is made in step 350, the process returns to step 340. On the other hand, if a negative determination is made in step 350, the process proceeds to step 360.

  In step 360, the CPU 30 performs positional deviation correction with a correction amount corresponding to the detection result of the simple positional deviation amount detection in step 348. Hereinafter, the correction of the positional deviation according to the detection result of the simple positional deviation amount detection is referred to as simple positional deviation correction. Note that the correction amount for the simple misalignment correction may be reduced by a predetermined ratio or amount as compared with the correction amount in the normal misalignment correction control.

  In step 362, the CPU 30 adjusts the execution timing (execution timing) of the next misregistration correction control. Since the simple misalignment correction is performed by control different from the misalignment correction control, if the next execution timing is not adjusted as it is, the temperature does not rise so much from the temperature when the simple misalignment correction is executed. Further, misregistration correction control may be executed, and on the contrary, the waiting time for image formation may increase. Therefore, here, the execution timing of the next misregistration correction control is adjusted to be later than the next execution timing defined by the misregistration correction execution condition.

  For example, when the simple misregistration correction is handled in the same way as normal misregistration correction control and the temperature rises by t ° C. (2 ° C. in the present embodiment) from the temperature at which the simple misregistration correction is executed. You may adjust so that the next positional offset correction control may be performed. Specifically, the positional deviation correction control is normally performed at 12 ° C., 14 ° C.,... If the temperature when the simple positional deviation correction is performed is 13 ° C., the next time The misalignment correction control is adjusted to be performed when the temperature reaches 15 ° C. instead of 14 ° C.

  Further, the next misalignment correction control is executed when the temperature becomes a temperature obtained by adding a predetermined temperature s ° C. to the temperature that defines the execution timing of the next misalignment correction control determined by the misalignment correction execution condition. You may adjust as follows. More specifically, when the misregistration correction control is normally performed as 12 ° C., 14 ° C.,..., When simple misalignment correction is performed at 13 ° C. and s ° C. is 0.5 ° C. The next misalignment correction control is adjusted so as to be performed at 14.5 ° C. instead of 14 ° C.

  After step 362, the process returns to step 340.

  [Fourth Embodiment]

  In the present embodiment, the image forming apparatus 20 is provided with two operation modes: a productivity-oriented mode and an image quality-oriented mode. When the image forming apparatus 20 is set to the productivity-oriented mode by the user, the correction control execution process described with reference to FIG. 17 in the third embodiment is performed. When the image quality emphasis mode is set, the misregistration correction control is executed individually using the misregistration correction execution condition as a trigger, and the density correction control is executed individually using the density correction execution condition as a trigger.

  FIG. 18 is a flowchart showing a flow of correction control execution processing executed when the image forming apparatus 20 is set to the image quality emphasis mode by the user. In step 390, the CPU 30 determines whether or not a predetermined misalignment correction execution condition is satisfied. Here, when a negative determination is made, the process proceeds to step 392.

  In step 392, the CPU 30 determines whether or not a predetermined density correction execution condition is satisfied. If a negative determination is made here, the process returns to step 390.

  If an affirmative determination is made in step 390, the process proceeds to step 394. In step 394, the CPU 30 performs normal misalignment correction control. This misregistration correction control is the same as the misregistration correction control described with reference to FIG. After the normal misalignment correction control, the process returns to step 390.

  If an affirmative determination is made in step 392, the process proceeds to step 396. In step 396, the CPU 30 performs normal density correction control. This density correction control is the same as the density correction control described with reference to FIG. After the normal density correction control, the process returns to step 390.

  FIG. 19 is a flowchart showing the flow of mode selection processing.

  In step 400, the CPU 30 displays an operation mode selection screen on the UI 24.

  In step 402, the CPU 30 determines whether or not the user has operated the UI 24 to select an operation mode. In step 402, the standby state is continued until the user selects an operation mode.

  When the CPU 30 determines in step 402 that the user has selected the productivity-oriented mode, the CPU 30 proceeds to step 404 and sets the operation mode of the image forming apparatus 20 to the productivity-oriented mode. Thereby, the image forming apparatus 20 executes the correction control execution process of FIG.

  On the other hand, if the CPU 30 determines in step 402 that the user has selected the image quality emphasis mode, the CPU 30 proceeds to step 406 and sets the operation mode of the image forming apparatus 20 to the image quality emphasis mode. Thereby, the image forming apparatus 20 executes the correction control execution process of FIG.

  In the first to fourth embodiments, the example in which the number of prints is defined as the density correction execution condition and the temperature in the apparatus is defined as the positional deviation correction execution condition has been described. However, the present invention is not limited to this. Not. For example, time may be defined as a density correction execution condition (for example, T time has elapsed since the previous density correction control), or humidity in the apparatus may be defined as a positional deviation correction execution condition (for example, The humidity f f fluctuated from the previous misregistration correction control).

It is a block diagram which shows an example of a structure of the image forming apparatus which concerns on the 1st-4th embodiment. It is a block diagram which shows the structure of a main control part. It is a block diagram of an image forming part. (A) is a figure which shows the example of arrangement | positioning of an optical sensor, (B) is a schematic block diagram of an optical sensor. (A) is a figure which shows an example of position shift detection image P1, (B) is a figure which shows an example of density detection image P2, (C) is a figure which shows an example of combined use detection image P4. . The positional relationship between the V-shaped displacement detection image P1 formed on the intermediate transfer belt and the visual field region R of the optical sensor on the intermediate transfer belt is shown, and sensor output signals and signals output from the optical sensor The pulse signal output from the processing circuit is shown along with the passage of time. It is a modification of the pulse signal generated by the signal processing circuit. The positional relationship between the density detection image P2 formed on the intermediate transfer body belt and the visual field area R on the intermediate transfer body belt 6 of the optical sensor is shown, and the sensor output signal output from the optical sensor is shown with time. FIG. It is a flowchart which shows the flow of position shift correction control. It is a flowchart which shows the flow of density correction control. It is a flowchart which shows the flow of the correction | amendment control execution process which concerns on 1st Embodiment. (A) is a diagram showing an example of execution timing of misregistration correction control when misregistration correction control is performed every 2 ° C., and (B) is a case where density correction control is performed for every 100 printed sheets. FIG. 6C is a diagram illustrating an example of the execution timing of density correction control in FIG. 6C, and FIG. 5C is a diagram illustrating the execution timing of position deviation correction control in FIG. It is. (A) is the same figure as FIG. 12 (C), (B) is the figure which showed the execution timing of the correction control at the time of performing the correction control execution process shown in FIG. It is a flowchart which shows the modification of the correction | amendment control execution process which concerns on 1st Embodiment. (A) is accompanied by the rotation of the intermediate transfer body belt 6 between the dual-purpose detection image P4 formed on the intermediate transfer body belt 6 and the center of the field area R of the optical sensor when no positional deviation occurs. It is the figure which showed the positional relationship with the thick arrow, (B) is a figure which shows the state when the position shift has occurred in the first direction, (C) is the position in the first direction and the second direction It is a figure which shows a state when deviation | shift generate | occur | produced. It is a flowchart which shows the flow of the correction control execution process which concerns on 2nd this Embodiment. It is a flowchart which shows the flow of the correction control execution process which concerns on 3rd Embodiment. 14 is a flowchart illustrating a flow of correction control execution processing that is executed when the image quality emphasis mode is set in the fourth embodiment. It is a flowchart which shows the flow of the mode selection process which concerns on 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Contact charger 4 Developer 5 Primary transfer device 6 Intermediate transfer belt 7 Secondary transfer device 10 Optical sensor 12 Light emitting unit 14 Light receiving unit 16 Signal processing circuit 20 Image forming apparatus 22 Main control unit 24 UI
26 Image formation control unit 28 Image formation unit 29 Detection unit 30 CPU
36 UI controller 40 interface 42 communication interface 44 bus

Claims (9)

Detecting means for detecting reflected light or transmitted light from the image transferred to the transferred body by an image forming means for forming an image of a plurality of colors and transferring it to the transferred body;
When the image forming unit satisfies a predetermined density correction execution condition, the image forming unit is controlled to form a density detection image for detecting the density of each color image, and the detecting unit The image forming means is corrected so that the density of the image formed by the image forming means is corrected based on the density of each color detected based on the reflected light or transmitted light from the density detection image detected in step S2. When the density correction control to be controlled is executed and a predetermined positional deviation correction execution condition is satisfied in the image forming unit, a positional deviation detection image for detecting the positional deviation of each color image is formed. The image forming unit is controlled, and the image formation is performed based on the amount of misregistration detected based on reflected light or transmitted light from the misregistration detection image detected by the detecting unit. A positional deviation correction control for controlling the image forming unit so that the positional deviation of the image formed in a stage is corrected, and the image forming unit performs one of the density correction execution condition and the positional deviation correction execution condition. When the correction execution condition is satisfied and a predetermined condition as an allowable range of the other correction execution condition is satisfied, the image forming unit is controlled so that the density detection image and the positional deviation detection image are formed. The density of the image formed by the image forming unit is corrected based on the density of each color detected based on the reflected or transmitted light from the density detection image detected by the detecting unit. While controlling the image forming unit, based on the amount of displacement detected based on the reflected light or transmitted light from the displacement detection image detected by the detection unit, Execution means for executing a density positional deviation correction control a positional shift of an image formed by the serial image forming means controls the image forming means so as to be corrected,
A control device comprising: Detecting means for detecting reflected light or transmitted light of the image transferred to the transferred body by an image forming means for forming an image of a plurality of colors and transferring it to the transferred body;
When the image forming unit satisfies a predetermined density correction execution condition, the image forming unit is controlled so that a combined detection image for detecting the density and misregistration of each color image is formed; The image is formed so that the density of the image formed by the image forming unit is corrected based on the density of each color detected based on the reflected or transmitted light from the combined detection image detected by the detecting unit. When density correction control for controlling the forming unit is executed, and the amount of misalignment detected based on the reflected or transmitted light from the combined detection image detected by the detecting unit is out of a predetermined allowable range When the image forming unit satisfies a predetermined misregistration correction execution condition, a misregistration detection image for detecting misregistration of each color image is formed. The position of the image formed by the image forming unit based on the amount of misregistration detected based on the reflected or transmitted light from the misregistration detected image detected by the detecting unit by controlling the image forming unit. Execution means for executing positional deviation correction control for controlling the image forming means so that deviation is corrected;
A control device comprising: Detecting means for detecting reflected light or transmitted light of the image transferred to the transferred body by an image forming means for forming an image of a plurality of colors and transferring it to the transferred body;
When the image forming unit satisfies a predetermined misregistration correction execution condition, the image forming unit is controlled to form a misregistration detection image for detecting misregistration of each color image; The positional deviation of the image formed by the image forming means is corrected based on the positional deviation amount detected based on the reflected light or transmitted light from the positional deviation detected image detected by the detection means. When the first misregistration correction control for controlling the image forming unit is executed and the predetermined density correction execution condition is satisfied in the image forming unit, the image forming unit is used to detect the density and misregistration of each color image. The image forming unit is controlled so that a detection image is formed, and the density for each color detected based on reflected or transmitted light from the combined detection image detected by the detection unit Based on this, the first density correction control is performed to control the image forming means so that the density of the image formed by the image forming means is corrected, and the reflection from the combined detection image detected by the detection means. When the amount of misregistration detected based on light or transmitted light falls outside a predetermined allowable range, the image formed by the image forming unit is determined based on the misregistration amount of the detected combined use image. The image forming unit is controlled so that the misregistration is corrected, and the next execution timing of the first misregistration correction control is adjusted to be later than the next execution timing determined by the misregistration correction execution condition. First execution means for executing second positional deviation correction control,
A control device comprising: When the density correction execution condition is satisfied in the image forming unit, the image forming unit is controlled so that a density detection image for detecting the density of the image of each color is formed, and is detected by the detection unit. A second control unit configured to control the image forming unit so that a density of an image formed by the image forming unit is corrected based on a density of each color detected based on reflected light or transmitted light from the density detection image; A second execution unit that executes density correction control and executes the first position correction control when the image forming unit satisfies the position shift correction execution condition;
Selecting means for selecting an operation mode of the image forming means;
Switching means for switching the execution means to be operated to one of the first execution means and the second execution means according to the selection result of the selection means;
The control device according to claim 3, further comprising: When the first execution unit controls the image forming unit so that the positional deviation is corrected by the second positional deviation correction control, the first execution unit corrects the positional deviation by the first positional deviation correction control. The control device according to claim 3, wherein control is performed so that correction is performed with a correction amount that is smaller than a correction amount when the image forming unit is controlled. Image forming means for forming an image of a plurality of colors and transferring the image to a transfer target;
The control device according to any one of claims 1 to 5,
An image forming apparatus. On the computer,
When the predetermined density correction execution condition is satisfied in the image forming unit that forms a multi-color image and transfers it to the transfer target, a density detection image for detecting the density of each color image is formed. And detecting based on the reflected or transmitted light from the density detection image detected by the detecting means for controlling the image forming means and detecting reflected or transmitted light from the image transferred to the transfer object And executing density correction control for controlling the image forming unit so that the density of the image formed by the image forming unit is corrected based on the density for each color.
When the image forming unit satisfies a predetermined misregistration correction execution condition, the image forming unit is controlled to form a misregistration detection image for detecting misregistration of each color image; The positional deviation of the image formed by the image forming means is corrected based on the positional deviation amount detected based on the reflected light or transmitted light from the positional deviation detected image detected by the detection means. Execute misregistration correction control to control the image forming means,
When the image forming unit satisfies one correction execution condition of the density correction execution condition and the positional deviation correction execution condition, and satisfies a predetermined condition as an allowable range of the other correction execution condition, the density The image forming unit is controlled so that a detection image and the misregistration detection image are formed, and the density for each color is detected based on reflected light or transmitted light from the density detection image detected by the detection unit. Based on the reflected light or transmitted light from the misregistration detection image detected by the detection means and controlling the image formation means so that the density of the image formed by the image formation means is corrected. Based on the amount of misregistration detected in this step, the density misregistration compensation is performed to control the image forming unit so that the misregistration of the image formed by the image forming unit is corrected. Program for executing a control. On the computer,
When the predetermined density correction execution condition is satisfied in the image forming unit that forms a multi-color image and transfers it to the transfer target, a combined detection image for detecting the density and misregistration of the image of each color is provided. Based on the reflected light or transmitted light from the combined detection image detected by the detecting means for controlling the image forming means to be formed and detecting reflected light or transmitted light of the image transferred to the transfer object Density correction control for controlling the image forming unit so that the density of the image formed by the image forming unit is corrected based on the density for each color detected
A position shift amount detected based on reflected light or transmitted light from the combined detection image detected by the detection unit is outside a predetermined allowable range; and a predetermined position in the image forming unit. When the deviation correction execution condition is satisfied, the image forming unit is controlled so as to form a misregistration detection image for detecting misregistration of each color image, and the misregistration detected by the detection unit. Misregistration correction control for controlling the image forming unit so that the misregistration of the image formed by the image forming unit is corrected based on the misregistration amount detected based on reflected light or transmitted light from the detected image. A program for running On the computer,
When image forming means for forming a multi-color image and transferring it to a transfer medium satisfies a predetermined misregistration correction execution condition, a misregistration detection image for detecting misregistration of each color image is displayed. The reflected light or transmitted light from the misregistration detection image detected by the detecting means for controlling the image forming means to be formed and detecting reflected light or transmitted light of the image transferred to the transfer target. First misregistration correction control for controlling the image forming unit so that the misregistration of the image formed by the image forming unit is corrected based on the misregistration amount detected based on
When the image forming unit satisfies a predetermined density correction execution condition, the image forming unit is controlled so that a combined detection image for detecting the density and misregistration of each color image is formed; The image is formed so that the density of the image formed by the image forming unit is corrected based on the density of each color detected based on the reflected or transmitted light from the combined detection image detected by the detecting unit. Perform density correction control to control the forming means,
If the amount of misalignment detected based on the reflected or transmitted light from the combined detection image detected by the detection means is outside a predetermined allowable range, the detected misalignment of the combined detection image The image forming unit is controlled so that the positional deviation of the image formed by the image forming unit is corrected based on the amount, and the next execution timing of the first positional deviation correction control is the positional deviation correction execution condition. A program for executing the second misalignment correction control that is adjusted so as to be later than the next execution time determined in (1).