JP6048205B2 - Image forming apparatus and image forming apparatus control method - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus that forms an image using color materials of a plurality of colors and a control method therefor, and in particular, image formation having a function of adjusting a shift in image forming position due to the plurality of color materials. The present invention relates to an apparatus and a control method thereof.

  Conventionally, in a color image forming apparatus, a plurality of color materials (for example, ink and toner, in this specification, “toner” is used as a specific color material in an electrophotographic image forming apparatus) are used. It is necessary to accurately superimpose the toner image formed on the image carrier of the above color on an intermediate transfer member such as a transfer belt.

  However, the image transfer position with respect to the transfer belt may be shifted between a plurality of colors due to machine accuracy, transfer belt speed fluctuation, and the like. Also, due to temperature changes, the distance between the image carriers for each color and the length of the transfer belt change, the distance between the colors changes, and the image transfer position onto the transfer belt may shift between colors.

  That is, the color misregistration appears as color misregistration. In order to prevent this color misregistration, a color misregistration measurement pattern (hereinafter referred to as “color resist pattern”) is formed on the transfer belt, and color misregistration correction is performed based on the detection result of this color resist pattern. (Hereinafter referred to as “registration adjustment”).

  The following patent documents 1 and 2 disclose various techniques for resist adjustment.

JP 2011-170318 A JP 2011-102940 A

  In the above Patent Document 1, as the resist adjustment in the image forming apparatus that outputs the color toner such as YMCK and the colorless clear toner in an overlapping manner, the overlapping of the two color toners from the pattern in which the clear toner and the color toner are completely overlapped is performed. A technique is described in which a plurality of patterns whose amounts are changed in stages are formed, density values are measured, a resist deviation amount is calculated based on the density values, and resist adjustment is performed.

  In Patent Document 2 described above, in an image forming system that separately includes a first image forming apparatus that forms a colored toner image and a second image forming apparatus that forms a colorless toner image, the first image forming apparatus A test pattern based on a color toner image is formed on a test sheet on which a test pattern based on a color toner image is formed by a second image forming apparatus, and an image formation position deviation is calculated based on the detection timing of the two color test patterns. A technique for adjusting the position of the colorless toner image of the second image forming apparatus is described.

  By the way, the required image forming position accuracy may differ between the colored toner image and the colorless toner image. For example, since a colorless toner image is used on the entire surface of a sheet, a predetermined range (such as the upper half of the sheet), or a watermark or background pattern on a sheet, the required image forming position accuracy is lower than that of a colored toner image. There are many cases.

  However, regardless of the image forming position accuracy, uniform registration adjustment is performed for the colored toner image and the colorless toner image, and the time required for the registration adjustment and the toner consumed by the registration adjustment are wasted. This technique for reducing waste has not been proposed in other documents including the above patent documents.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and when the required image forming position accuracy is different between the colored toner image and the colorless toner image, the time required for the resist adjustment and the toner consumed by the resist adjustment. An object of the present invention is to realize an image forming apparatus and an image forming apparatus control method capable of appropriately performing registration adjustment between a colored toner image and a colorless toner image without causing waste.

That is, the present invention for solving the above-described problems is as follows.
(1) An image forming unit that executes a job for forming an image using a colorless color material and a plurality of colored color materials on recording paper based on image data, and using one of the colored colors as a reference color, A control unit having a function of performing registration adjustment for adjusting an image forming position of a color material of another color with respect to an image forming position of the reference color material, or an image forming apparatus control method. The control unit has a function of controlling color registration adjustment for at least one color and a function of controlling colorless resist adjustment for colorless, and for a job to be executed at a colorless image forming position. According to the two types of required accuracy, high accuracy and non-high accuracy, when the high accuracy is required and at the registration adjustment timing, the colorless resist adjustment and If the non-high accuracy is required and the registration adjustment timing is required, the colorless registration adjustment is performed with the same accuracy as the colored registration adjustment before the execution of the job. By not executing the control, the colorless resist adjustment is controlled to be executed more easily than the colored resist adjustment.

  (2) In the above (1), the control unit executes the colorless resist adjustment more easily than the colored resist adjustment by executing the colorless resist adjustment at a lower accuracy than the colored resist adjustment. It is characterized by that.

  (3) In the above (1)-(2), the control unit performs the colorless resist adjustment more frequently than the colored resist adjustment by executing the colorless resist adjustment at a lower frequency than the colored resist adjustment. It is easy to execute.

  (4) In the above (1) to (3), the control unit determines that the colorless resist adjustment is looser than a range in which image forming position deviation is recognized as normal than the colored resist adjustment. The colorless resist adjustment is performed more simply than the colored resist adjustment.

  (5) In the above (1) to (4), the control unit forms a resist adjustment mark having a predetermined shape and detects the position of the resist adjustment mark, thereby executing the resist adjustment. The colorless resist adjustment is performed more easily than the colored resist adjustment by making the number of resist adjustment marks formed by the colorless resist adjustment smaller than the number of resist adjustment marks formed by the colored resist adjustment. To do.

(1) An image forming apparatus or an image forming apparatus control method that solves the above-described problems has a function of controlling colored resist adjustment for at least one color and a function of controlling colorless resist adjustment for colorlessness. Since the colorless resist adjustment can be executed more easily than the colored resist adjustment, the time required for the colorless resist adjustment and the colorless registration can be reduced when the required image formation position accuracy differs between the colored toner image and the colorless toner image. It is possible to appropriately perform registration adjustment between a colored toner image and a colorless toner image without causing waste due to toner consumed by registration adjustment.
If the job to be executed requires non-high accuracy according to two types of accuracy, high accuracy and non-high accuracy, which are required at the colorless image forming position, the colorless resist adjustment is performed. Since it can be executed more easily than the adjustment, the time required for the colorless resist adjustment and the toner consumed by the colorless resist adjustment when the required image formation position accuracy differs between the colored toner image and the colorless toner image. Therefore, it is possible to appropriately perform registration adjustment between the colored toner image and the colorless toner image without causing waste. On the other hand, if the job to be executed requires high accuracy according to the two types of accuracy, high accuracy and non-high accuracy, which are required at the colorless image forming position, and the registration adjustment timing, Colorless registration adjustment and colored registration adjustment are controlled to be executed with the same accuracy before execution. Therefore, if the image formation position accuracy required for the colored toner image and the colorless toner image is both high, Resist adjustment and colorless resist adjustment can be executed with appropriate accuracy.

  (2) In the above (1), since the colorless resist adjustment is controlled to be executed with lower accuracy than the colored resist adjustment, the required color formation position is different between the colored toner image and the colorless toner image. Therefore, it is possible to appropriately perform registration adjustment between a colored toner image and a colorless toner image without causing waste due to time required for colorless resist adjustment and toner consumed by colorless resist adjustment.

  (3) In the above (1)-(2), since the colorless resist adjustment is controlled to be executed at a lower frequency than the colored resist adjustment, an image forming position required for the colored toner image and the colorless toner image is required. When the accuracy is different, it is possible to appropriately perform registration adjustment between a colored toner image and a colorless toner image without causing waste due to the time required for colorless resist adjustment and toner consumed by colorless resist adjustment. .

  (4) In the above (1) to (3), since the colorless resist adjustment is controlled so as to determine the range in which the image forming position shift is recognized as being normal rather than the colored resist adjustment, the color toner image and the colorless toner image are controlled. When the required image formation position accuracy differs between toner images, the registration of colored toner images and colorless toner images can be done without waste due to the time required for colorless resist adjustment or toner consumed by colorless resist adjustment. Can be properly executed.

  (5) In the above (1) to (4), when a resist adjustment mark having a predetermined shape is formed and the position of the resist adjustment mark is detected, the resist adjustment is performed by colorless resist adjustment. Since the number of registration adjustment marks is controlled to be less than the number of registration adjustment marks formed by colored registration adjustment, when the required image formation position accuracy differs between colored toner images and colorless toner images, colorless registration adjustment is possible. It is possible to appropriately perform registration adjustment between a colored toner image and a colorless toner image without causing waste due to the time required and toner consumed by the colorless resist adjustment.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 1 is a configuration diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. It is explanatory drawing which shows an example of the chart used for a resist adjustment with the image forming apparatus of embodiment of this invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows an example of the chart used for a resist adjustment with the image forming apparatus of embodiment of this invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows the mode of the determination of the registration adjustment of the image forming apparatus of embodiment of this invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows an example of the chart used for a resist adjustment with the image forming apparatus of embodiment of this invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.
<Configuration of image forming apparatus>
FIG. 1 shows a system configuration of an image forming apparatus 100 according to the first embodiment of the present invention.

  The image forming apparatus 100 includes a printer controller 110 and an image forming unit 120. The printer controller 110 is connected to an information processing apparatus 20 such as a personal computer (PC) via a network 30 such as a LAN (Local Area Network), and rasterizes a print job sent from the information processing apparatus 20. The function of executing processing for generating image data (RIP processing) is achieved. The image data is bitmap format data used for image formation.

  The print job received by the printer controller 110 from the information processing apparatus 20 includes print data in which characters and figures are represented by code data and vector data, for example, print data described in PDL (Page Description Language). It is a waste. The rasterization process (RIP process) in the printer controller 110 is a process for developing print data composed of code data and vector data into image data in a bitmap format.

  The image forming unit 120 receives print job data including image data (hereinafter referred to as job data) from the printer controller 110, and forms a color image or a monochrome image on recording paper based on the image data. Fulfills the print output function. Here, the image forming unit 120 is configured as a so-called digital color multifunction peripheral having a copy function for optically reading a document and forming a duplicate image on a recording sheet in addition to a print output function.

  The printer controller 110 includes a CPU (Central Processing Unit) 111 that performs overall control of the operation of the printer controller 110, a LAN-IF unit 112 that performs a communication function for connection to the network 30, and image data generated by RIP processing. For example, an image memory 113 for storing the data, a hard disk device (HDD) 114 for storing print data received from the network 30, intermediate data generated in the course of the RIP processing, and data read / write to the image memory 113 And a DRAM control unit 115 that performs a function of transmitting and receiving various data to and from the image forming unit 120.

  In addition, although not shown in the figure, the CPU 111 temporarily stores programs (ROMs) that are read and executed by the CPU 111 and various data when the CPU 111 executes the programs. A working memory is connected.

  FIG. 2 shows a schematic mechanical configuration of the image forming unit 120. The image forming unit 120 includes a scanner unit 122 including an automatic document feeder 121, an operation display unit 123, a printer unit 124 that forms and outputs an image on a recording sheet, and a main control unit 150. .

  The automatic document feeder 121 has a function of feeding the originals J stacked on the original placement tray 121a one by one to the reading portion of the scanner unit 122 and discharging the read originals J 'to the paper output tray 121b.

  The scanner unit 122 performs a function of optically reading the original J in color or monochrome and acquiring corresponding image data. The scanner unit 122 includes an exposure scanning unit including a light source and a mirror, a color line image sensor 122a that receives reflected light from a document and outputs an electrical signal corresponding to the light intensity, and reflected light from the document. Are provided with various mirrors, condenser lenses, and the like for guiding the light to the line image sensor 122a. The scanner unit 122 can read the document while the document is placed on the platen glass in addition to the flow reading format in which the document is conveyed by the automatic document feeder 121 and moved relative to the reading position. .

  The printer unit 124 includes a plurality of stages of image forming units, and includes an endless annular intermediate transfer belt 131 and a plurality of image forming units 140CL, 140Y, and 140M that respectively form single color toner images on the intermediate transfer belt 131. 140C and 140K, a paper feed unit 132 that feeds recording paper on which an image is formed, a transport unit 133 that transports the fed recording paper, and a fixing device 134. Here, the image forming units 140Y, 140M, 140C, and 140K form a colored toner image, and the image forming unit 140CL forms a colorless (transparent: clear) toner image.

  Note that toner and ink correspond to the color material as a material used for forming an image, but in this embodiment, toner is a specific example of the color material for electrophotographic image formation.

Colored is a color that is not transparent, and includes achromatic and chromatic colors. Yellow (Y), magenta (M), cyan (C), black (K), and the like are mainly used.
Colorless means transparent (clear (CL)), and is a material that produces gloss, reflection, watermark, etc. Including not only completely colorless, but also some color and minute glossy substances A material may be used, and in this embodiment, clear (CL) is taken as a specific example.

  The image forming unit 140CL forms a clear (CL) color image on the intermediate transfer belt 131, the image forming unit 140Y forms a yellow (Y) image on the intermediate transfer belt 131, and the image forming unit 140M sets magenta. An (M) color image is formed on the intermediate transfer belt 131, the image forming unit 140C forms a cyan (C) color image on the intermediate transfer belt 131, and the image forming unit 140K is a black (K) color image. Are formed on the intermediate transfer belt 131.

  The image forming unit 140CL includes a photosensitive member 141CL as a cylindrical electrostatic latent image carrier on which an electrostatic latent image is formed, and a charging device 142CL, a developing device 143CL, and a cleaning device 144CL disposed around the photosensitive member 141CL. Have Further, a laser unit 145CL including a laser diode, a polygon mirror, various lenses, a mirror, and the like is provided. The photoconductor 141CL is driven by a driving unit (not shown) and rotates in a certain direction (the direction of arrow A in the figure), and the charging device 142CL uniformly charges the photoconductor 141CL. The laser unit 145CL forms an electrostatic latent image on the surface of the photoreceptor 141CL by scanning the photoreceptor 141CL with laser light turned on / off according to colorless (CL color) image data. The developing device 143CL visualizes the electrostatic latent image on the photoreceptor 141CL with colorless toner. The toner image formed on the surface of the photoreceptor 141CL is transferred to the intermediate transfer belt 131 at a location where it contacts the intermediate transfer belt 131. The cleaning device 144CL functions to remove and collect the toner remaining on the surface of the photoreceptor 141CL after the transfer by rubbing with a blade or the like.

  The image forming unit Y, the image forming unit 140M, the image forming unit 140C, and the image forming unit 140K have different toner colors, and the laser light of the laser unit is turned on / off with image data corresponding to each color. Is the same as the image forming unit 140CL, and redundant description thereof is omitted. In the figure, elements having the same configuration but different colors have the same number, and the symbols Y (corresponding to the Y color) and M (corresponding to the M color) indicating the color instead of the subscript CL. , C (corresponding to C color), and K (corresponding to K color).

  The intermediate transfer belt 131 is wound around a plurality of rollers and circulates in the direction of arrow B in the figure during image formation. In the process of turning, the images (toner images) of the respective colors in the order of (CL), (Y), (M), (C), (K) are transferred to the intermediate transfer belt by the image forming units 140CL, 140Y, 140M, 140C, 140K. A color image is synthesized by being superimposed on 131. This color image is transferred from the intermediate transfer belt 131 to the recording paper at the secondary transfer position D. The arrangement order of the image forming units 140CL, 140Y, 140M, 140C, and 140K is an example, and the present invention is not limited to this.

A belt cleaning device 135 for removing toner remaining on the intermediate transfer belt 131 after the transfer is installed downstream of the secondary transfer position D in the circumferential direction.
The paper feed unit 132 has a plurality of paper feed cassettes 132a to 132c that store recording papers used for image formation, and transports recording paper one by one from one of the selected paper feed cassettes 132a to 132c. It fulfills the function of sending out to 133. The transport unit 133 passes the secondary transfer position D and the fixing device 134 through the recording paper fed from the paper supply unit 132 and discharges the recording paper to a post-processing device (not shown) or a paper discharge tray. In addition, a reverse path 133b that reverses the front and back sides of the recording paper that has passed through the fixing device 134 and then merges again with the normal path 133a upstream of the secondary transfer position D is provided, which supports double-sided printing.

  The post-processing device is a device having a function of making a crease in a recording sheet, bundling a plurality of recording sheets, binding them with staples, or making holes with a punch, and is connected to the subsequent stage of the image forming unit 120. . The processing content in the post-processing device is specified by a control command output from the main control unit 150 of the image forming unit 120 to the post-processing device.

  Returning to FIG. 1, the electrical configuration of the image forming unit 120 will be described. The image forming unit 120 is configured by connecting a scanner unit 122, a printer unit 124, and an operation display unit 123 to a main control unit 150 that performs overall control of the operation of the image forming unit 120.

In addition to the line image sensor 122a shown in FIG. 2, the scanner unit 122 includes a scanner control unit 122b that controls the entire operation of the scanner unit 122.
In addition to each laser diode (LD) 124a that is turned on / off according to image data, the printer unit 124 includes an intermediate transfer belt 131, image forming units 140CL, 140Y, 140M, 140C, and 140K, a paper feeding unit 132, and a conveyance unit 133. The printer controller 124b controls the operation of the fixing device 134 and the like. In addition, although not shown, the printer control unit 124b includes a motor for operating the intermediate transfer belt 131, the image forming units 140CL, 140Y, 140M, 140C, and 140K, the paper feeding unit 132, the conveying unit 133, and the like. Solenoid, sensor, etc. are connected.

  The operation display unit 123 has a function for displaying various setting screens, operation screens, job selection screens, job editing screens, output reservation job list screens, etc., a function for displaying various guidance information, notifications, warnings, and the like for the operator. Functions to receive various setting / selection operations, editing operations, and output instructions (image formation start instructions). The operation display unit 123 includes a display unit 123a formed of a liquid crystal display, an operation unit 123b formed of a touch switch and other switches laid on the screen, and an operation control unit 123c that controls the display unit 123a and the operation unit 123b. It is comprised.

  The scanner control unit 122b, the operation control unit 123c, and the printer control unit 124b are configured by circuits each having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as main parts. Various controls are executed in accordance with programs stored in the ROM.

  The main control unit 150 performs a function of overall control of the operation of the image forming unit 120, and includes a reading processing unit 152, a DRAM (Dynamic Random Access Memory) control unit 153, a compression IC 154a, a decompression IC 154b, and a semiconductor memory. The image memory 155, the write processing unit 158, the CPU 151, the ROM 159a, the RAM 159b, the nonvolatile memory 159c, the hard disk device 156 (also referred to as HDD), and the like are configured.

  The CPU 151 functions to control the entire operation of the image forming unit 120. The ROM 159a stores a program, various fixed data, and the like, and the CPU 151 operates according to the program stored in the ROM 159a. The RAM 159b is used as a work memory that temporarily stores various data when the CPU 151 executes a program. The nonvolatile memory 159c is a memory that stores user data, system data, various setting values, and the like that should be stored even after the power is turned off. A print queue described later is created and stored in the RAM 159b or the nonvolatile memory 159c.

The reading processing unit 152 has a function of performing enlargement processing, mirror image processing, error diffusion processing, and the like on the image data output from the scanner unit 122.
The DRAM control unit 153 controls read / write timing and refresh timing for the image memory 155 composed of dynamic RAM, compresses the image data and stores the compressed data in the compressed memory 155b, and reads and decompresses the compressed image data from the compressed memory 155b. Control the timing when you do. The DRAM control unit 153 is connected to the DRAM control unit 115 of the printer controller 110 through a PCI (Peripheral Component Interconnect) bus 104 and performs a function of transferring various data to and from the printer controller 110 through the PCI bus 104. .

  The compression IC 154a compresses the image data, and the decompression IC 154b functions to decompress the compressed image data (compressed image data) into the original uncompressed image data. The image memory 155 is used as a function as a page memory 155a capable of storing uncompressed image data in units of pages, a compression memory 155b storing compressed image data, and the like.

The hard disk device 156 stores and stores print job data (job data) received from the printer controller 110.
The writing processing unit 158 outputs a signal for turning on / off the laser diodes of the laser units 145CL, 145Y, 145M, 145C, and 145K according to the image data read out from the compression memory 155b and expanded. It performs the function of outputting at a timing according to.

  The sensor 160 is a detection unit that reads density patches, registration adjustment marks, and the like formed on the intermediate transfer belt 131, and the detection result is transmitted to the CPU 151. In this embodiment, it has at least a function of reading a registration adjustment mark formed on the intermediate transfer belt 131.

  Here, the printer controller 110 is shown as being incorporated in the image forming apparatus 100. When the printer controller 110 is provided outside the image forming apparatus 100, data transmission / reception between the printer controller 110 and the image forming unit 120 is performed using an interface suitable for that.

<Operation of image forming apparatus>
<Registration adjustment>
Here, an image forming operation in the image forming apparatus of the present embodiment will be described focusing on registration adjustment.

  3 is an example of a registration adjustment mark formed on the intermediate transfer belt 131. Here, for each color of CL, Y, M, C, and K, 3 at the end, center, and end in the main scanning direction. This shows a state in which a plurality of registration adjustment marks are attached, and registration adjustment marks in each color order are attached in five colors in the sub-scanning direction or the traveling direction of the intermediate transfer belt 131.

  Such registration adjustment marks are formed on the intermediate transfer belt 131 at a predetermined timing, and the registration adjustment marks for the respective colors formed on the intermediate transfer belt 131 are read by the sensor 160. For example, color (Y, M, C, One color (for example, K) of K) is used as a reference color, and the image formation position by the toner of another color (for example, CL, Y, M, C) is compared with the image formation position by the toner of the reference color. The shift is detected, and the image forming position is adjusted so as to eliminate the shift.

  In this case, as the registration adjustment marks, those having various shapes can be used, but those having a "F" shape composed of a line parallel to the main scanning direction and an oblique line can be used. it can. By using the registration adjustment mark having such a shape, the positions in the main scanning direction and the sub-scanning direction can be detected. This principle is already known, and details thereof are omitted.

<Overall operation>
By the way, the required image forming position accuracy may differ between the colored toner images of Y, M, C, and K and the colorless toner image of CL. For example, since the CL colorless toner image is used on the entire surface of the sheet, a predetermined range (such as the upper half of the sheet), or a watermark or background pattern on the sheet, the required image forming position accuracy may be low. is there.

  On the other hand, since the specific toner image is superimposed on the specific color toner image in the page to give the gloss and gloss of the specific image, not only the color toner image but also the image formation position accuracy of the colorless toner image may be important. .

  Therefore, when executing the registration adjustment, the main control unit 150 can perform control so that the colorless registration adjustment for the colorless toner image is performed more easily than the colored registration adjustment for the colored toner image. Features.

Here, “simple execution” means that the colorless resist adjustment is controlled to be executed with lower accuracy than the colored resist adjustment.
As described above, the colorless resist adjustment is performed more easily than the colored resist adjustment, that is, the colorless resist adjustment is performed with lower accuracy than the colored resist adjustment, so that an image required for the colored toner image and the colorless toner image is obtained. When the formation position accuracy is different, it is possible to properly perform registration adjustment between colored toner images and colorless toner images without causing waste due to the time required for colorless resist adjustment and toner consumed by colorless resist adjustment. become.

  A specific example in which colorless resist adjustment is performed more easily or less accurately than colored resist adjustment will be described below using specific examples (1) to (3), and colorless toner is designated in the high accuracy mode. A specific example in which the colorless resist adjustment and the colored resist adjustment are executed with the same accuracy will be described below using a specific example (4).

<Specific example (1)>
In the specific example (1) of this embodiment, both “colored” and “colorless” image forming positions are highly accurate “image quality priority mode”, and “colorless” image forming positions are not necessary for colorless and “colored image forming positions” are important. Consider a case in which image formation is controlled in three modes, a “balance mode” intermediate between an image quality priority mode and a speed priority mode.

The main control unit 150 periodically executes the processing of the flowchart of FIG. 4 as to whether or not to perform registration adjustment.
First, the main control unit 150 confirms whether the current time is the registration adjustment timing (step S101 in FIG. 4). Here, the registration adjustment timing refers to a state in which a predetermined number of image formations are performed or the operation time of the image forming unit 120 for a predetermined time has elapsed since the previous registration adjustment execution. It means that there is.

If the current time is not the registration adjustment timing (NO in step S101 in FIG. 4), the main control unit 150 ends the process of the flowchart in FIG. 4 (“END” in FIG. 4).
On the other hand, if the current time is the registration adjustment timing (YES in step S101 in FIG. 4), the main control unit 150 increments the parameter CountReg_NUM of the number of color registration execution (step S102 in FIG. 4).

  Then, the main control unit 150 confirms whether the image quality mode of the job currently being executed or about to be executed is image quality priority (step S103 in FIG. 4). In this specific example (1), as described above, a case is considered in which image formation is controlled in the three modes of “image quality priority mode”, “speed priority mode”, and “balance mode”.

  If the image quality mode of the job being executed or about to be executed is image quality priority (YES in step S103 in FIG. 4), the main control unit 150 executes registration adjustment in all colors (colored + colorless). (Step S106 in FIG. 4) is set, and the parameter CountReg_NUM of the number of color resist executions is reset (Step S107 in FIG. 4).

  On the other hand, if the image quality mode of the job being executed or about to be executed is not image quality priority (NO in step S103 in FIG. 4), the main control unit 150 determines that the image quality mode of the job being executed or about to be executed is speed priority. (Step S104 in FIG. 4).

  Here, if the image quality mode of the job being executed or about to be executed is speed priority (YES in step S104 in FIG. 4), the main control unit 150 performs registration adjustment in a color other than colorless. Setting is made (step S108 in FIG. 4).

  On the other hand, if the image quality mode of the job being executed or about to be executed is not speed priority, that is, the balance mode (NO in step S104 in FIG. 4), the main control unit 150 sets the parameter CountReg_NUM for the number of times of color registration execution. The all color color resist execution threshold value AllCountReg_NUM is compared (step S105 in FIG. 4).

  Here, the color registration execution count parameter CountReg_NUM is a value corresponding to the number of registration adjustments to be executed from now on, and is actually incremented every time color registration adjustment is executed, and the registration adjustment for all colors is performed. Cleared after execution. That is, it is a value corresponding to the number of times the colored registration adjustment is to be executed after the registration adjustment for all colors is executed.

  In addition, for the all-color color registration execution threshold AllCountReg_NUM, when CountReg_NUM becomes equal to AllCountReg_NUM at the timing when the registration adjustment is to be performed, the calculation for performing registration adjustment for all colors instead of colored registration adjustment Is the threshold value.

  Therefore, if CountReg_NUM ≧ AllCountReg_NUM is not satisfied (NO in step S105 in FIG. 4), the number of color registration adjustments has not reached the threshold value AllCountReg_NUM, and thus the main control unit 150 performs color registration except for colorlessness. It sets so that it may perform (step S108 in FIG. 4).

  On the other hand, if CountReg_NUM ≧ AllCountReg_NUM is satisfied (YES in step S105 in FIG. 4), the number of colored registration adjustments has reached the threshold value AllCountReg_NUM, so that the main control unit 150 performs registration adjustment for all colors. It is set (step S106 in FIG. 4), and the parameter CountReg_NUM of the number of color resist executions is reset (step S107 in FIG. 4).

Then, the main control unit 150 executes all-color or colored registration adjustment set as described above (step S109 in FIG. 4).
In the above operation, increasing the value of the all-color color registration execution threshold AllCountReg_NUM increases the frequency of colored registration adjustment and decreases the frequency of all-color registration adjustment. However, since the registration adjustment of all colors is executed when the value of the all color registration execution threshold AllCountReg_NUM is reached, the registration adjustment is also periodically executed even for the achromatic color although it is infrequent.

  That is, in the above specific example (1), since the colorless resist adjustment is controlled to be executed less frequently than the colored resist adjustment, the required image forming position accuracy differs between the colored toner image and the colorless toner image. In this case, it is possible to appropriately perform the resist adjustment between the colored toner image and the colorless toner image without causing waste due to the time required for the colorless resist adjustment or the toner consumed by the colorless resist adjustment.

  Here, the resist adjustment mark as shown in FIG. 3 is formed in the case of all color registration adjustment, but in the case of the color resist adjustment, the CL registration adjustment mark is omitted and the resist adjustment mark as shown in FIG. Since the adjustment mark is formed, the effects of reducing the adjustment time and reducing the amount of colorless toner used can be obtained. Further, when the image quality priority mode or the number of registration adjustments reaches a threshold value, registration adjustment for all colors including colorless toner is executed, so that necessary accuracy is maintained even for a colorless toner image.

<Specific example (2)>
In the specific example (2) of this embodiment, both “color priority” and “color priority” are high-precision “image quality priority mode”, and “color priority” is important because the color image formation position is important when it is colorless. Consider a case where image formation is controlled in two modes.

The main control unit 150 periodically executes the process of the flowchart of FIG. 6 as to whether or not to perform registration adjustment.
First, the main control unit 150 confirms whether the current time is the registration adjustment timing (step S201 in FIG. 6). Here, the registration adjustment timing refers to a state in which a predetermined number of image formations are performed or the operation time of the image forming unit 120 for a predetermined time has elapsed since the previous registration adjustment execution. It means that there is.

If the current time is not the registration adjustment timing (NO in step S201 in FIG. 6), the main control unit 150 ends the process of the flowchart in FIG. 6 (“END” in FIG. 6).
On the other hand, if the current time is the registration adjustment timing (YES in step S201 in FIG. 6), the main control unit 150 confirms whether the image quality mode of the job currently being executed or about to be executed is image quality priority. (Step S202 in FIG. 6). In this specific example (2), a case is considered in which image formation is controlled in two modes of “image quality priority mode” and “speed priority mode”.

  If the image quality mode of the job being executed or about to be executed is image quality priority (YES in step S202 in FIG. 6), the main control unit 150 sets the normal range threshold value for the colorless registration adjustment and the colored registration adjustment. Set equal (step S203 in FIG. 6). For example, when the registration adjustment mark (see FIG. 3) is read, the main control unit 150 determines whether the color (Y, M, C) registration mark image formation position deviation from the reference K registration mark and the reference As for the image forming position deviation of the colorless (CL) registration mark with respect to the K registration mark, 10 pixels are determined as the normal range threshold.

  On the other hand, if the image quality mode of the job being executed or about to be executed is speed priority rather than image quality priority (NO in step S202 in FIG. 6), the main control unit 150 sets the normal range threshold for colorless registration adjustment to a colored range. It is set to be looser than the normal range threshold for registration adjustment (step S204 in FIG. 6). For example, when the registration adjustment mark (see FIG. 3) is read, the main control unit 150 sets 10 pixels for the image formation position deviation of the colored (Y, M, C) registration mark with respect to the reference K registration mark. The normal range threshold is set, and 20 pixels are set as the normal range threshold with respect to the image formation position deviation of the colorless (CL) registration mark with respect to the reference K registration mark.

Then, the main control unit 150 performs registration adjustment for all colors (colored + colorless) with the normal range threshold set as described above (step S205 in FIG. 6).
In the image quality priority mode, when the registration adjustment mark (see FIG. 3) is read, the main controller 150 forms the image formation position of the colored (Y, M, C) registration mark with respect to the reference K registration mark. If the deviation is within 10 pixels, it is determined to be normal, and if the image formation position deviation is 11 pixels or more, it is determined to be an error (see “Image quality priority” in FIG. 7). Further, the main control unit 150 determines that the colorless (CL) registration mark image formation position deviation with respect to the reference K registration mark is within 10 pixels, and determines that the image formation position deviation is 11 pixels or more. If it is an error, In other words, in the image quality priority mode, the normal range threshold value of the image forming position deviation is set to 10 pixels for both the colored resist adjustment and the colorless resist adjustment, and the high-quality resist is generated without causing a difference between colored and colorless. Make adjustments.

  On the other hand, in the speed priority mode, when the registration adjustment mark (see FIG. 3) is read, the main control unit 150 displays an image of a colored (Y, M, C) registration mark with respect to the reference K registration mark. If the formation position deviation is within 10 pixels, it is determined to be normal, and if the image formation position deviation is 11 pixels or more, it is determined to be an error (see “Speed priority” in FIG. 7). The main control unit 150 determines that the image forming position deviation of the colorless (CL) registration mark with respect to the reference K registration mark is within 20 pixels, and determines that the image forming position deviation is 21 pixels or more. It is determined that there is an error. That is, in the speed priority mode, since the normal range of colorless resist adjustment is determined to be loose relative to the colored resist adjustment, the resist adjustment itself is performed for colorless (CL), but the number of adjustments is reduced. Occurs.

  Accordingly, since the colorless resist adjustment is controlled so as to determine a range in which the image formation position shift is recognized as being normal compared to the colored resist adjustment, the image forming position accuracy required for the colored toner image and the colorless toner image is improved. In different cases, it is possible to appropriately perform the resist adjustment between the colored toner image and the colorless toner image without causing waste due to the time required for the colorless resist adjustment or the toner consumed by the colorless resist adjustment.

In addition, since the resist adjustment itself is performed for colorless (CL), a phenomenon in which the resist misalignment for colorless is prevented can be prevented.
In this specific example (2), an example of two modes of the image quality priority mode and the speed priority mode has been shown. However, the present invention is not limited to this, and colorless registration adjustment is performed in three or more modes in three or more modes. It is also possible to determine the strictness of the determination criteria.

<Specific example (3)>
In the specific example (3) of this embodiment, both the colored and colorless image forming positions are high-precision “image quality priority mode”, and the non-colorless color forming position is not necessary and the “color priority” is important. Consider a case where image formation is controlled in two modes.

  In the specific example (2) described above, in the speed priority mode, the normal range threshold for colorless resist adjustment is set to be looser than the normal range threshold for colored resist adjustment. On the other hand, in the specific example (3), in the case of registration adjustment in the speed priority mode, the CL registration adjustment marks are formed with a smaller number than the K, C, M, and Y registration adjustment marks.

The main control unit 150 periodically executes the process of the flowchart of FIG. 8 as to whether or not to perform registration adjustment.
First, the main control unit 150 confirms whether the current time is the registration adjustment timing (step S301 in FIG. 8). Here, the registration adjustment timing refers to a state in which a predetermined number of image formations are performed or the operation time of the image forming unit 120 for a predetermined time has elapsed since the previous registration adjustment execution. It means that there is.

If the current time is not the registration adjustment timing (NO in step S301 in FIG. 8), the main control unit 150 ends the process of the flowchart in FIG. 8 (“END” in FIG. 8).
On the other hand, if the current time is the registration adjustment timing (YES in step S301 in FIG. 8), the main control unit 150 confirms whether the image quality mode of the job currently being executed or about to be executed is image quality priority. (Step S302 in FIG. 8). In this specific example (3), a case is considered in which image formation is controlled in two modes of “image quality priority mode” and “speed priority mode”.

  If the image quality mode of the job being executed or about to be executed is image quality priority (YES in step S302 in FIG. 8), the main control unit 150 sets the number of registration adjustment marks for each color in the color resist pattern to an equal number. For example, in the color resist pattern of FIG. 3, the number of K, C, M, Y, CL registration adjustment marks is set equal to 5 in the sub-scanning direction at each position in the main scanning direction (step in FIG. 8). S303).

  On the other hand, if the image quality mode of the job being executed or about to be executed is speed priority instead of image quality priority (NO in step S302 in FIG. 8), the main control unit 150 sets the CL registration adjustment mark for registration adjustment. The number is set to be smaller than the number of registration adjustment marks of K, C, M, and Y (step S304 in FIG. 8). For example, in the color resist pattern of FIG. 3, the number of K, C, M, and Y registration adjustment marks is 5 in the sub-scanning direction at each position in the main scanning direction, and the number of CL registration adjustment marks is each position in the main scanning direction. To set three in the sub-scanning direction.

  Then, the main control unit 150 performs registration adjustment for all colors (colored and colorless) with the color registration pattern in which the number of registration adjustment marks is set as described above (step S305 in FIG. 8).

  Accordingly, in the image quality priority mode, registration adjustment is executed by reading five registration adjustment marks (see K, C, M, and Y in FIG. 3) at each position in the main scanning direction for all colors. The main control unit 150 controls each unit so as to do this.

  In the speed priority mode, five registration adjustment marks (see K, C, M, and Y in FIG. 9) are provided at each position in the main scanning direction for colored (K, C, M, and Y). The main control unit 150 controls each unit to read and execute registration adjustment. Then, for the colorless (CL), three registration adjustment marks (see CL in FIG. 9) in the sub-scanning direction are read at each position in the main scanning direction, and the main control unit 150 controls each unit so as to execute registration adjustment.

  In this specific example (3), in the registration adjustment in the image quality priority mode, five CL registration adjustment marks are formed in the same manner as the registration adjustment marks for K, C, M, and Y, but the registration in the speed priority mode is performed. In the case of adjustment, the number of CL registration adjustment marks is set to a small number to form registration adjustment marks as shown in FIG. 9, reducing the color resist pattern creation time, reducing the color resist pattern reading time, and adjusting the resist. The effects of reducing processing time, reducing resist adjustment time, and reducing the amount of colorless toner used can be obtained.

In addition, since the registration adjustment itself is performed for colorless (CL), a phenomenon in which the resist misalignment for colorless is prevented can be prevented.
Further, in this specific example (3), the two modes of the image quality priority mode and the speed priority mode are shown. However, the present invention is not limited to this, and the number of colorless registration adjustment marks is 3 in three or more modes. You may make it fix to the number of steps or more.

<Specific example (4)>
Hereinafter, a specific example (4) of the embodiment will be described with reference to the flowchart of FIG.

  First, when a job is input (step S401 in FIG. 10), the main control unit 150 analyzes the contents of the job and determines whether colorless (CL) toner is used for image formation (in FIG. 10). Step S402).

  When colorless (CL) toner is not used for image formation (NO in step S402 in FIG. 10), the main control unit 150 controls each unit to start job processing (image formation) (FIG. 10 step S406).

  On the other hand, when colorless (CL) toner is used for image formation (YES in step S402 in FIG. 10), the main control unit 150 determines the accuracy of the colorless (CL) toner image based on the contents of the analyzed job. It is determined whether or not the (image quality) mode is designated (step S403 in FIG. 10).

  Here, when the high-precision (high-quality) mode is not designated for the colorless (CL) toner image (NO in step S403 in FIG. 10), the main control unit 150 starts job processing (image formation). Each part is controlled so as to perform (step S406 in FIG. 10).

  On the other hand, when the high accuracy (high image quality) mode is designated for the colorless (CL) toner image (YES in step S403 in FIG. 10), the main control unit 150 checks whether the current time is the registration adjustment timing. (Step S404 in FIG. 10).

  Note that the registration adjustment timing is a state in which, for example, a predetermined number of images are formed or the operation time of the image forming unit 120 for a fixed time has elapsed since the previous registration adjustment execution. It means that. In this embodiment, since control is performed with respect to a colorless (CL) toner image, the registration adjustment timing means that a predetermined number of images are formed starting from the previous registration adjustment execution including colorlessness. It is desirable that the operation time of the image forming unit 120 for a certain time elapses.

  For example, when a predetermined number of images have not been formed or a certain amount of operation time has not elapsed since the previous registration adjustment, the previous registration adjustment is a colored registration adjustment (step S108 in FIG. 4). It is desirable to determine the number of image formations and the elapsed operation time from the point of registration adjustment including colorless (CL) before that.

  If the current time is not the registration adjustment timing (NO in step S404 in FIG. 10), the main control unit 150 controls each unit to start job processing (image formation) (step S406 in FIG. 10). .

  On the other hand, colorless (CL) toner is used for image formation (YES in step S402 in FIG. 10), and a high-precision (high image quality) mode is designated for the colorless (CL) toner image (in FIG. 10). If the current time is the registration adjustment timing (YES in step S404 in FIG. 10), the main control unit 150 determines that the image quality priority all colors described in the specific examples (1) to (3) above are present. Each part is controlled to execute the registration adjustment (step S405 in FIG. 10), and thereafter, each part is controlled to start job processing (image formation) (step S406 in FIG. 10).

  That is, when the colorless (CL) toner is used with high accuracy, the main control unit 150 may execute both the colored registration adjustment and the colorless registration adjustment with high accuracy before the job starts at the registration adjustment timing. Control each part. On the other hand, when no colorless (CL) toner is used, when colorless (CL) toner is not used with high accuracy, when colorless (CL) toner is used with high accuracy but not at the registration adjustment timing, it corresponds to any one of them. For example, high-precision colorless resist adjustment is not executed before the job starts. For this reason, it is possible to appropriately perform registration adjustment between the colored toner image and the colorless toner image without waste.

<Other embodiments>
The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to that shown in the embodiment, and there are changes and additions within the scope of the present invention. Are also included in the present invention.

In addition, the resist adjustment marks in the above color resist pattern are only examples, and various modifications are possible.
Further, in combination with the above specific example (2) and specific example (3), in the speed priority mode, the normal range threshold for colorless resist adjustment is set to be looser than the normal range threshold for colored resist adjustment, and for colorless CL It is also possible to perform control such that the number of registration adjustment marks is controlled to be smaller than the number of colored K, C, M, and Y registration adjustment marks. In this way, by performing colorless resist adjustment more simply than colored resist adjustment, it is possible to appropriately perform resist adjustment between a colored toner image and a colorless toner image without waste.

100 Image forming apparatus 104 PCI bus 110 Printer controller 111 CPU
112 LAN-IF unit 113 Image memory 114 Hard disk device (HDD)
115 DRAM Control Unit 120 Image Forming Unit 121 Automatic Document Feeder 121a Document Placement Tray 121b Paper Discharge Tray 122 Scanner Unit 122a Line Image Sensor 122b Scanner Control Unit 123 Operation Display Unit 123
123a Display unit 123b Operation unit 123c Operation control unit 124 Printer unit 124a LD
124b Printer control unit 131 Intermediate transfer belt 132 Paper feed unit 132a Paper feed cassette 133 Transport unit 133a Normal path 133b Reverse path 134 Fixing device 135 Belt cleaning devices 140CL, 140Y, 140M, 140C, 140K Image forming units 141CL, 141Y, 141M, 141C, 141K Photoconductor 142CL, 142Y, 142M, 142C, 142K Charging device 143CL, 143Y, 143M, 143C, 143K Developing device 144CL, 144Y, 144M, 144C, 144K Cleaning device 145CL, 145Y, 145M, 145C, 145K Laser unit 150 Main control unit 151 CPU
152 Reading Processing Unit 153 DRAM Control Unit 154a Compression IC
154b Extension IC
155 Image memory 155a Page memory 155b Compression memory 156 Hard disk drive (HDD)
158 Write processing unit 159a ROM
159b RAM
159c nonvolatile memory

Claims (10)

An image forming unit that executes a job for forming an image using a colorless color material and a plurality of colored color materials on recording paper based on image data ;
A control unit having a function of performing registration adjustment for adjusting an image forming position by a color material of another color with respect to an image forming position by a color material of the reference color using one of the colors as a reference color;
An image forming apparatus comprising:
Wherein,
Having a function of controlling the color resist adjustment for at least one color, and a function of controlling the colorless resist adjustment for colorless;
For jobs to be executed, depending on two types of accuracy, high accuracy and non-high accuracy, which are required at the colorless image forming position,
When the high accuracy is required and it is the registration adjustment timing, the colorless registration adjustment and the colored registration adjustment are executed with the same accuracy before the execution of the job,
If the non-high accuracy is required and it is the registration adjustment timing, the colorless registration adjustment is not performed with the same accuracy as the colored registration adjustment for the colorless registration adjustment before executing the job. Control to execute easier than adjustment ,
An image forming apparatus. The control unit performs the colorless resist adjustment more easily than the colored resist adjustment by performing the colorless resist adjustment at a lower accuracy than the colored resist adjustment.
The image forming apparatus according to claim 1. The control unit performs the colorless resist adjustment more easily than the colored resist adjustment by performing the colorless resist adjustment at a lower frequency than the colored resist adjustment.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit performs the colorless resist adjustment more easily than the colored resist adjustment by determining that the colorless resist adjustment is more gradual than the colored resist adjustment in a range that is recognized to be normal with respect to the deviation of the image forming position. ,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The controller is
When performing the registration adjustment by forming a registration adjustment mark of a predetermined shape and detecting the position of the registration adjustment mark,
The colorless resist adjustment is performed more easily than the colored resist adjustment by reducing the number of resist adjustment marks formed by the colorless resist adjustment to be less than the number of resist adjustment marks formed by the colored resist adjustment.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. An image forming unit that executes a job for forming an image using a colorless color material and a plurality of colored color materials on recording paper based on image data, and using the one of the colored colors as a reference color, the reference color An image forming apparatus control method for controlling the operation of the image forming apparatus, the controller having a function of performing registration adjustment for adjusting the image forming position of the color material of another color with respect to the image forming position of the color material of There,
Having a function of controlling the color resist adjustment for at least one color, and a function of controlling the colorless resist adjustment for colorless;
For the job to be executed, the control unit has two types of accuracy, high accuracy and non-high accuracy, as the accuracy required at the colorless image forming position.
When the high accuracy is required and it is the registration adjustment timing, the colorless registration adjustment and the colored registration adjustment are executed with the same accuracy before the execution of the job,
If the non-high accuracy is required and it is the registration adjustment timing, the colorless registration adjustment is not performed with the same accuracy as the colored registration adjustment for the colorless registration adjustment before executing the job. Control to execute easier than adjustment ,
An image forming apparatus control method. The colorless resist adjustment is performed more easily than the colored resist adjustment by performing the colorless resist adjustment at a lower accuracy than the colored resist adjustment.
The image forming apparatus control method according to claim 6 . The control unit performs the colorless resist adjustment more easily than the colored resist adjustment by performing the colorless resist adjustment at a lower frequency than the colored resist adjustment.
Claim 6, characterized in that - 7 or the image forming apparatus control method according to one of. The colorless resist adjustment is performed more easily than the colored resist adjustment by determining the range in which image forming position deviation is recognized to be normal more gently than the colored resist adjustment.
Claim 6, characterized in that - 8 image forming apparatus control method according to any one of. By forming a resist adjustment mark of a predetermined shape and detecting the position of the resist adjustment mark, the number of resist adjustment marks formed by the colorless resist adjustment is formed by the colored resist adjustment when the resist adjustment is executed. The colorless resist adjustment is performed more easily than the colored resist adjustment by reducing the number of registration adjustment marks to be less,
9 or the image forming apparatus control method according to one of - claim 6, characterized in that.