JP7081212B2 - Image forming device, screen pattern determination method and program - Google Patents

Description

The present invention relates to an image forming apparatus, a method for determining a screen pattern, and a program.

Embossed paper has irregularities on its surface and has a different texture from plain paper, and is used for printing invitations and the like. However, in the recesses on the surface of the embossed paper, an air layer is formed between the toner layer adhering to the intermediate transfer belt and the embossed paper, so that image quality deterioration such as transfer omission (white omission) as shown in FIG. 10 occurs. ..

As a technique for suppressing image quality deterioration of a recording medium having irregularities on the surface of embossed paper or the like, for example, in Patent Document 1, a surface shape measuring device is provided upstream of an intermediate transfer portion to provide surface irregularities on the recording paper. A technique is described in which the amount of undulations is measured, and when the undulations are large, the exposure position of the first color and the exposure position of the second color are arranged so as not to overlap.

Japanese Unexamined Patent Publication No. 2008-12627

However, the technique described in Patent Document 1 requires a special sensor for detecting unevenness on the surface of the recording paper.

An object of the present invention is to suppress deterioration of image quality of an image formed on an uneven recording medium having irregularities formed on the surface of embossed paper or the like without using a special sensor for detecting irregularities on the surface of the recording medium. be.

In order to solve the above problems, the invention according to claim 1 is
In an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A storage means for storing multiple different screen patterns,
A detection means for detecting the amount of residual toner remaining on the image carrier after transfer, and
A plurality of patches generated by using a plurality of screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of an uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of residual toner amounts of the plurality of patches are detected based on the detected residual toner amount of each of the plurality of patches. A screen pattern determining means for determining a screen pattern used for screen processing when forming an image on the uneven recording medium from among the screen patterns.
To prepare for.

The invention according to claim 2 is the invention according to claim 1.
The screen pattern determining means uses the screen pattern having the largest number of screen lines among the screen patterns used to generate the patches having a residual toner amount less than a predetermined standard among the plurality of patches as the uneven recording medium. It is determined as a screen pattern to be used when forming an image.

The invention according to claim 3 is the invention according to claim 1 or 2.
The image forming apparatus forms a toner image on the photoconductor for each color component by the developing device for each color component, and the toner image formed on the photoconductor for each color component is used as an intermediate as the image carrier. After sequentially superimposing and transferring on the transfer body, the toner image transferred to the intermediate transfer body is transferred to the recording medium.

The invention according to claim 4 is the invention according to claim 3.
After forming a plurality of patches having different numbers of stacked color components on the intermediate transfer body and transferring the plurality of patches formed on the intermediate transfer body to the uneven recording medium, the patch remaining on the intermediate transfer body. The developing apparatus used for detecting the residual toner amount of each of the plurality of patches by the detection means and forming an image on the uneven recording medium based on the detected residual toner amount of each of the plurality of patches. A development parameter determining means for determining a development parameter is provided.

The invention according to claim 5 is the invention according to claim 4.
The development parameter determining means is based on the toner amount of the patch in which the residual toner amount in the intermediate transfer body is less than a predetermined standard among the plurality of patches and the number of superimposed color components is the smallest. , The development parameters are determined.

The invention according to claim 6 is the invention according to claim 4 or 5.
When forming the plurality of patches on the image carrier, the screen pattern determining means forms a plurality of patches on the image carrier using the development parameters determined by the development parameter determining means.

The invention according to claim 7 is
A method for determining a screen pattern in an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A plurality of patches generated by using a plurality of different screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of the uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of screens are based on the detected residual toner amount of each of the plurality of patches. From the patterns, a screen pattern used for screen processing when forming an image on the uneven recording medium is determined.

The program of the invention according to claim 8 is
A computer used for an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A plurality of patches generated by using a plurality of different screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of the uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of screens are based on the detected residual toner amount of each of the plurality of patches. From the patterns, it functions as a screen pattern determining means for determining a screen pattern used for screen processing when forming an image on the uneven recording medium.

According to the present invention, it is possible to suppress deterioration of image quality of an image formed on an uneven recording medium having irregularities formed on the surface of embossed paper or the like without using a special sensor for detecting irregularities on the surface of the recording medium. can.

It is a figure which shows the schematic structure of the image forming apparatus. It is a block diagram which shows the main functional composition of an image forming apparatus. It is a flowchart which shows the transferability adjustment process A executed by the control part of FIG. 2 in 1st Embodiment. It is a flowchart which shows the transferability adjustment process B executed by the control part of FIG. 2 in the 2nd Embodiment. It is a figure which shows the state of the patch for determining the development parameter on the intermediate transfer belt before transfer to the embossed paper schematically. It is a figure which shows the state which transferred the patch for determining the development parameter shown in FIG. 5 to the concave part of the embossed paper deep in the concave part. It is a figure which shows the state which transferred the patch for determining the development parameter shown in FIG. 5 to the concave part of the embossed paper which is shallower than the embossing shown in FIG. It is a figure which shows the state which transferred the patch for determining the development parameter shown in FIG. 5 to the concave part of the embossed paper which is shallower than the embossing shown in FIG. It is a figure which shows the state which transferred the patch for determining the development parameter shown in FIG. 5 to the plain paper which does not have a recess. It is a figure which shows the example of transfer omission in embossed paper.

Hereinafter, the present embodiment will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

<First Embodiment>
FIG. 1 is a diagram schematically showing an overall configuration of an image forming apparatus 1 according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a main functional configuration of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 shown in FIGS. 1 and 2 is an intermediate transfer type color image forming apparatus using an electrophotographic process technique. That is, the image forming apparatus 1 sequentially superimposes the toner images of the Y (yellow), M (magenta), C (cyan), and K (black) color components formed on the photoconductor drum 413 on the intermediate transfer belt 421. After the transfer (primary transfer), the image is formed on the paper by transferring it to the paper (secondary transfer).

The image forming apparatus 1 employs a tandem method in which the photoconductor drums 413 corresponding to the four colors of YMCK are arranged in series in the traveling direction of the intermediate transfer belt 421, and the toner images of each color are sequentially transferred to the intermediate transfer belt 421. ..

As shown in FIG. 2, the image forming apparatus 1 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper transport unit 50, a fixing unit 60, a storage unit 70, a communication unit 80, and an image forming unit 1. The control unit 100 is provided.

The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and the like. The CPU 101 reads a program according to the processing content from the ROM 102, develops it in the RAM 103, and centrally controls the operation of each block of the image forming apparatus 1 shown in FIG. 2 in cooperation with the expanded program. For example, when the image data of a job is input by the image reading unit 10 or the communication unit 80, the control unit 100 executes the job, controls the operation of each block, and forms a sheet of paper based on the input image data. Form an image. Further, the control unit 100 executes various processes including the transferability adjustment process A, which will be described later, according to the user operation.
The control unit 100 functions as a screen pattern determining means and a developing parameter determining means.

The image reading unit 10 includes an automatic document feeding device 11 called an ADF (Auto Document Feeder), a document image scanning device 12 (scanner), and the like.
The automatic document feeding device 11 conveys the document D placed on the document tray by the conveying mechanism and sends it out to the document image scanning device 12. The automatic document feeding device 11 can continuously read a large number of images (including both sides) of the document D placed on the document tray at once.

The document image scanning device 12 optically scans the document conveyed on the contact glass from the automatic document feeding device 11 or the document placed on the contact glass, and the reflected light from the document is CCD (Charge Coupled Device). ) An image is formed on the light receiving surface of the sensor 12a, and the original image is read. The image reading unit 10 generates job image data based on the scanning result by the document image scanning device 12. Predetermined image processing is applied to this image data by the image processing unit 30.

The operation display unit 20 is composed of, for example, a liquid crystal display (LCD: Liquid Crystal Display) with a touch panel, and functions as a display unit 21 and an operation unit 22. The display unit 21 displays various operation screens, an image status display, an operation status of each function, and the like according to a display control signal input from the control unit 100. The operation unit 22 includes various operation keys such as a numeric keypad and a start key, receives various input operations by the user, and outputs an operation signal to the control unit 100.

The image processing unit 30 performs various image processing such as color conversion processing, gradation correction processing, and screen processing on the input image data. An image is formed on paper by the image forming unit 40 based on the image data subjected to these processes.

The image forming unit 40 is an image forming unit 41Y, 41M, 41C, 41K for forming an image with each colored toner of Y component, M component, C component, and K component based on the input image data after image processing. It includes an intermediate transfer unit 42 and the like.

The image forming units 41Y, 41M, 41C, 41K for the Y component, the M component, the C component, and the K component have the same configuration. For convenience of illustration and description, common components are indicated by the same reference numerals, and when distinguishing between them, the reference numerals are given with Y, M, C, or K. In FIG. 1, reference numerals are given only to the components of the image forming unit 41Y for the Y component, and the reference numerals are omitted for the other components of the image forming units 41M, 41C, and 41K.

The image forming unit 41 includes an exposure device 411, a developing device 412, a photoconductor drum 413, a charging device 414, a drum cleaning device 415, and the like.

The photoconductor drum (photoreceptor) 413 has, for example, an undercoat layer (UCL: Under Coat Layer) and a charge generation layer on the peripheral surface of a conductive cylinder (aluminum element tube) made of aluminum having a drum diameter of 80 [mm]. (CGL: Charge Generation Layer) and a charge transport layer (CTL: Charge Transport Layer) are sequentially laminated to form a negatively charged organic photo-conductor (OPC). The charge generation layer is made of an organic semiconductor in which a charge generation material (for example, a phthalocyanine pigment) is dispersed in a resin binder (for example, polycarbonate), and a pair of positive charges and negative charges are generated by exposure by an exposure apparatus 411. The charge transport layer is composed of a hole transporting material (electron donating nitrogen-containing compound) dispersed in a resin binder (for example, a polycarbonate resin), and transports positive charges generated in the charge generation layer to the surface of the charge transport layer. do.

The control unit 100 rotates the photoconductor drum 413 at a constant peripheral speed by controlling the drive current supplied to the drive motor (not shown) that rotates the photoconductor drum 413.

The charging device 414 uniformly charges the surface of the photoconductor drum 413 having photoconductivity to a negative electrode property. The exposure apparatus 411 is composed of, for example, a semiconductor laser, and irradiates the photoconductor drum 413 with a laser beam corresponding to an image of each color component. Positive charges are generated in the charge generation layer of the photoconductor drum 413 and transported to the surface of the charge transport layer, so that the surface charge (negative charge) of the photoconductor drum 413 is neutralized. An electrostatic latent image of each color component is formed on the surface of the photoconductor drum 413 due to the potential difference from the surroundings.

The developing apparatus 412 includes a developing sleeve 412a arranged so as to face the photoconductor drum 413 with the developing region interposed therebetween. For example, a DC development bias having the same polarity as the charging polarity of the charging device 414 or a development bias in which a DC voltage having the same polarity as the charging polarity of the charging device 414 is superimposed on the AC voltage is applied to the developing sleeve 412a. A developer is supplied onto the electrostatic latent image formed on the photoconductor drum 413 to form a toner image on the photoconductor drum 413. The developer includes a toner and a carrier for charging the toner. The toner is not particularly limited, and a commonly used known toner can be used. For example, a binder resin containing a colorant, a charge control agent, a mold release agent, or the like, if necessary, and treated with an external additive can be used.

The drum cleaning device 415 has a drum cleaning blade or the like that is slidably contacted with the surface of the photoconductor drum 413, and removes the transfer residual toner remaining on the surface of the photoconductor drum 413 after the primary transfer.

The intermediate transfer unit 42 includes an intermediate transfer belt (intermediate transfer body) 421 as an image carrier, a primary transfer roller 422, a plurality of support rollers 423, a secondary transfer roller 424, a belt cleaning device 426, an image density sensor 427, and the like. ..

The intermediate transfer belt 421 is composed of an endless belt and is stretched in a loop on a plurality of support rollers 423. At least one of the plurality of support rollers 423 is composed of a driving roller, and the other is composed of a driven roller. For example, it is preferable that the roller 423A arranged on the downstream side in the belt traveling direction with respect to the primary transfer roller 422 for the K component is the drive roller. This makes it easier to keep the running speed of the belt in the primary transfer unit constant. As the drive roller 423A rotates, the intermediate transfer belt 421 travels at a constant speed in the direction of arrow A.

The primary transfer roller 422 is arranged on the inner peripheral surface side of the intermediate transfer belt 421 so as to face the photoconductor drum 413 of each color component. The primary transfer roller 422 is pressed against the photoconductor drum 413 with the intermediate transfer belt 421 interposed therebetween, thereby forming a primary transfer nip for transferring the toner image from the photoconductor drum 413 to the intermediate transfer belt 421.

The secondary transfer roller 424 is arranged on the outer peripheral surface side of the intermediate transfer belt 421 so as to face the roller 423B (hereinafter referred to as “backup roller 423B”) arranged on the downstream side of the drive roller 423A in the belt traveling direction. The secondary transfer roller 424 is pressed against the backup roller 423B with the intermediate transfer belt 421 interposed therebetween, thereby forming a secondary transfer nip for transferring the toner image from the intermediate transfer belt 421 to the paper.

When the intermediate transfer belt 421 passes through the primary transfer nip, the toner image on the photoconductor drum 413 is sequentially superimposed on the intermediate transfer belt 421 and the primary transfer is performed. Specifically, a primary transfer bias is applied to the primary transfer roller 422, and a charge having a polarity opposite to that of the toner is applied to the back surface side (the side that abuts the primary transfer roller 422) of the intermediate transfer belt 421 to obtain a toner image. It is electrostatically transferred to the intermediate transfer belt 421.

After that, when the paper passes through the secondary transfer nip, the toner image on the intermediate transfer belt 421 is secondarily transferred to the paper. Specifically, the toner image is obtained by applying a secondary transfer bias to the secondary transfer roller 424 and applying a charge having the opposite polarity to the toner on the back surface side of the paper (the side that abuts on the secondary transfer roller 424). It is electrostatically transferred to the paper. The paper on which the toner image is transferred is conveyed toward the fixing unit 60.

The belt cleaning device 426 has a belt cleaning blade or the like that is in sliding contact with the surface of the intermediate transfer belt 421, and removes the transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer. Instead of the secondary transfer roller 424, a configuration in which a secondary transfer belt is stretched in a loop on a plurality of support rollers including the secondary transfer roller (so-called belt-type secondary transfer unit) is adopted. Is also good.

An image density sensor 427 is provided on the outer peripheral surface side of the intermediate transfer belt 421 on the downstream side in the belt traveling direction with respect to the secondary transfer roller 424. The image density sensor 427 is a sensor that detects the toner density of the patch formed on the intermediate transfer belt 421 to determine the maximum density and outputs the toner density to the control unit 100. The image density sensor 427 also detects the density of toner remaining on the surface of the intermediate transfer belt 421 after transferring a plurality of patches formed on the intermediate transfer belt 421 to embossed paper in the transferability adjusting process described later. Output to the control unit 100. The control unit 100 detects the amount of residual toner in each patch based on the concentration of the toner remaining in the intermediate transfer belt 421 detected by the image density sensor 427. That is, the image density sensor 427 and the control unit 100 function as detection means.

The fixing unit 60 secondarily transfers the toner image, and heats and pressurizes the conveyed paper with the fixing nip to fix the toner image on the paper.

The paper transport unit 50 includes a paper feed unit 51, a paper discharge unit 52, a transport path unit 53, and the like. The paper feed unit 51 includes paper feed tray units 51a to 51c for loading paper. The transport path portion 53 has a plurality of transport roller pairs such as a resist roller pair 53a.

The paper contained in the paper feed tray units 51a to 51c is sent out one by one from the uppermost portion, and is conveyed to the image forming unit 40 by the transfer path unit 53. At this time, the resist roller portion in which the resist roller pair 53a is arranged corrects the inclination of the fed paper and adjusts the transfer timing. Then, in the image forming unit 40, the toner image of the intermediate transfer belt 421 is collectively secondarily transferred to one surface of the paper, and the fixing step is performed in the fixing unit 60. The image-formed paper is discharged to the outside of the machine by the paper ejection unit 52 provided with the paper ejection roller 52a.

The storage unit 70 is composed of, for example, a non-volatile semiconductor memory (so-called flash memory), a hard disk drive, or the like. The storage unit 70 stores various data including various setting information related to the image forming apparatus 1. For example, a plurality of screen patterns having different angles, numbers of lines, and the like are stored in the storage unit 70 in association with the identification information of the screen patterns. Further, the storage unit 70 is associated with the identification information of each of the paper feed tray units 51a to 51c, and information about the paper loaded in the paper feed tray unit (paper type, basis weight, paper size, used). Screen patterns, development parameters, etc.) are stored.

The communication unit 80 is composed of a communication control card such as a LAN (Local Area Network) card, and is connected to an external device (for example, a personal computer) connected to a communication network such as a LAN or a WAN (Wide Area Network). Send and receive various data.

Next, the operation in the first embodiment will be described.
FIG. 3 is executed when the paper feed tray unit (any of the paper feed tray units 51a to 51c) is selected by the operation unit 22 and the embossed paper is set as the loaded paper in the first embodiment. It is a flowchart which shows the flow of the transferability adjustment process A. The transferability adjustment process A shown in FIG. 3 is executed in cooperation with the CPU 101 of the control unit 100 and the program stored in the ROM 102.

First, the control unit 100 feeds embossed paper from the selected paper feed tray unit, and has a predetermined gradation (one gradation) of a predetermined image (for example, a predetermined color (one color or a plurality of colors)). However, the image forming unit 41 intermediates a plurality of patches generated by performing screen processing using a plurality of screen patterns stored in the storage unit 70 for an image of a predetermined size (which may be a plurality of gradations). It is formed on the transfer belt 421 and transferred onto the fed embossed paper by the secondary transfer roller 424 (step S1).

Next, the control unit 100 causes the image density sensor 427 to detect the toner density of the intermediate transfer belt 421, and based on the detection result, the control unit 100 remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. The amount of residual toner is detected (step S2).

Next, the control unit 100 supplies the embossed paper (in step S1) with the screen pattern having the largest number of screen lines among the screen patterns used to generate the patch having a residual toner amount less than a predetermined standard. It refers to an embossed paper of the same type as the paper embossed paper, and is determined as a screen pattern used when forming an image on the embossed paper (not the embossed paper itself) fed in step S1 (step S3).

Here, in order to suppress transfer omission on embossed paper having irregularities on the surface, it is considered effective to select a screen pattern having few isolated points and a small number of lines, but the graininess deteriorates and the image quality deteriorates. Deteriorates. Therefore, among the screen patterns used to generate patches in which the amount of residual toner is less than a predetermined standard when transferred to embossed paper, the screen pattern with the largest number of screen lines is used as an image on the embossed paper in the job. It is determined as a screen pattern to be used when forming. Thereby, the optimum screen pattern in which transfer omission is suppressed and the deterioration of graininess is also suppressed can be determined as the screen pattern used when forming an image on the embossed paper in the job.

When the screen pattern is determined, the control unit 100 stores the determined screen pattern identification information in association with the identification information of the selected embossed paper input tray unit (step S4), and performs the transferability adjustment process A. finish.

When the start of the job is instructed, the control unit 100 determines the type of paper used in the job and the paper feed tray unit based on the setting information of the job, and the paper used is embossed paper, and the storage unit 70. When the identification information of the screen pattern is associated with the paper feed tray unit loaded with the paper to be used, the screen pattern is used when the image processing unit 30 performs screen processing on the image data of the job. The image data is screened.

For example, when loading paper such as plain paper having no unevenness on the surface into the paper feed tray unit loaded with embossed paper, the operation unit 22 selects and loads the corresponding paper feed tray unit. When plain paper is set as the selected paper, the control unit 100 stores information about the paper (paper of paper) stored in the storage unit 70 in association with the identification information of the selected paper feed tray unit. Seeds, basis weight, paper size, etc.) are updated. Delete the information of the screen pattern to be used.

As described above, according to the first embodiment, a plurality of patches obtained by performing screen processing using a plurality of screen patterns are formed on the intermediate transfer belt 421 by the image forming unit 41 and on the embossed paper. After transfer, the screen with the largest number of screen lines is the screen pattern used to detect the amount of residual toner remaining on the intermediate transfer belt 421 and generate a patch in which the detected residual toner amount is less than a predetermined standard. It is determined as a screen pattern used when forming an image on the embossed paper.
Therefore, it is possible to automatically determine a screen pattern that can suppress image quality deterioration such as transfer omission and deterioration of graininess of the image formed on the embossed paper as a screen pattern used when forming the image on the embossed paper. Therefore, it is possible to suppress image quality deterioration such as transfer omission and deterioration of graininess of the image formed on the embossed paper without using a special sensor for detecting unevenness on the paper surface.

In the first embodiment, the case where the present invention is applied to a color image forming apparatus has been described as an example, but the present invention may be applied to a monochrome image forming apparatus. When the present invention is applied to a monochrome image forming apparatus, an image density sensor is provided at a position facing the photoconductor drum on the downstream side of the nip portion with the transfer roller in the rotation direction of the photoconductor drum as an image carrier. The control unit forms a plurality of patches obtained by performing screen processing using a plurality of screen patterns on the photoconductor drum, transfers them onto embossed paper, and then applies the amount of toner remaining on the photoconductor drum for each patch. The screen pattern used to create the patch with the detected residual toner amount less than the predetermined standard, which has the largest number of screen lines, is used to form an image on the embossed paper. To be determined as. As a result, even in a monochrome image forming apparatus, it is possible to select the optimum screen pattern for the embossed paper to be used without using a special sensor for detecting the unevenness of the paper surface, and it is possible to select the optimum screen pattern for transfer omission and graininess. It is possible to suppress deterioration of image quality such as deterioration.

<Second embodiment>
Next, a second embodiment of the present invention will be described.
In the first embodiment, the case where the image quality deterioration such as transfer omission and deterioration of graininess is suppressed by selecting the optimum screen pattern according to the embossed paper to be used has been described, but the second embodiment has been described. First, an example of determining the optimum development parameters according to the embossed paper to be used and determining the optimum screen pattern when forming an image with the determined development parameters will be described.

Since the configuration of the image forming apparatus 1 in the second embodiment is the same as that described in the first embodiment, the description is incorporated, and the operation of the second embodiment will be described below.

In FIG. 4, in the second embodiment, the paper feed tray unit (any of the paper feed tray units 51a to 51c) is selected by the operation of the operation unit 22 of the user, and the embossed paper is set as the loaded paper. It is a flowchart which shows the flow of the transferability adjustment process B executed at the time. The transferability adjustment process B shown in FIG. 4 is executed in cooperation with the CPU 101 of the control unit 100 and the program stored in the ROM 102.

First, the control unit 100 feeds embossed paper from the selected paper feed tray unit, forms a plurality of patches for determining development parameters on the intermediate transfer belt 421 by the image forming unit 41, and causes the secondary transfer roller 424. Is transferred onto the embossed paper that has been fed (step S11).
The plurality of patches for determining the development parameters are a plurality of patches having different numbers of superimposed color components. For example, a patch P1 of a solid image of Y1 color, a patch P2 of a solid image of two colors of YM, a patch P3 of a solid image of three colors of YMC, and a patch P4 of a solid image of four colors of YMCK (see FIG. 5). ..

Next, the control unit 100 causes the image density sensor 427 to detect the toner density of the intermediate transfer belt 421, and based on the detection result, the control unit 100 remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. The amount of residual toner is detected (step S12).

Next, the control unit 100 is a patch in which the amount of residual toner remaining on the intermediate transfer belt 421 is less than a predetermined standard among the plurality of patches for determining the development parameters, and the number of superimposed color components is the smallest. When forming an image on the embossed paper (pointing to the same type of embossed paper as the embossed paper fed in step S11, not the embossed paper itself fed in step S11) based on the amount of toner in the job. The development parameters are determined (step S13).

FIG. 5 is a diagram schematically showing the state of patches P1 to P4 for determining development parameters on the intermediate transfer belt 421 before transfer to embossed paper. FIG. 6 is a diagram showing a state in which patches P1 to P4 for determining development parameters shown in FIG. 5 are transferred to the recesses of the embossed paper EP1 having deep recesses. FIG. 7 is a diagram showing a state in which patches P1 to P4 for determining development parameters shown in FIG. 5 are transferred to the recesses of the embossed paper EP2 having shallower recesses than the embossed EP1 shown in FIG. FIG. 8 is a diagram showing a state in which patches P1 to P4 for determining development parameters shown in FIG. 5 are transferred to the recesses of the embossed paper EP3 having shallower recesses than the embossed EP2 shown in FIG. 7. FIG. 9 is a diagram showing a state in which patches P1 to P4 for determining development parameters shown in FIG. 5 are transferred to plain paper EP0 having no recess.

As shown in FIG. 6, when embossed paper EP1 with deep recesses is used as the paper, only the patch P4 on which the solid images of YMCK 4 colors are superimposed is transferred to the recesses of the embossed paper EP1, and the number of superimposed color components is three colors. For the following patches P1 to P3, an air layer is formed between the recess of the embossed paper EP1 and the toner of the patch, so that the toner is not transferred to the recess of the embossed paper EP1 and remains as residual toner on the intermediate transfer belt 421. It ends up. That is, all the patches P1 to P3 are detected as residual toner, and in the patch P4, a slight amount of residual toner is detected or the amount of residual toner becomes 0. In this case, the control unit 100 uses a patch in which the amount of residual toner remaining on the intermediate transfer belt 421 is less than a predetermined standard (at least less than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameters. Therefore, the development parameter (development bias or development θ) is determined based on the amount of toner in the patch having the smallest number of overlapping color components. For example, in FIG. 6, when forming a solid image in each of the image forming units 41Y, M, C, and K, a toner image having the same amount of toner as patch P4 is formed on the intermediate transfer belt 421. Determine the development parameters (development bias or development θ). Here, the development θ is the ratio of the rotation speed of the development sleeve 412a to the rotation speed of the photoconductor drum 413 (rotation speed of the development sleeve 412a / rotation speed of the photoconductor drum 413). This makes it possible to suppress transcription omission. However, if the determined development parameter exceeds the upper limit of the device (for example, the toner consumption is too large when developing with the development parameter, the paper is wrapped around the fixing unit 60, etc.), the upper limit of the development parameter is used. A value in the range not exceeding is determined as a development parameter.

As shown in FIG. 7, when the embossed paper EP2 having a shallower recess than the embossed paper EP1 is used as the paper, the patches P3 to P4 having three or more overlapping color components are transferred to the recesses of the embossed paper EP2. However, for patches P1 to P2 in which the number of overlapping color components is two or less, an air layer is formed between the recess of the embossed paper EP2 and the toner of the patch, so that the toner is not transferred to the recess of the embossed paper EP2. , It remains as residual toner on the intermediate transfer belt 421. That is, all patches P1 to P2 are detected as residual toner, and patches P3 to P4 are detected with a small amount of residual toner, or the amount of residual toner becomes zero. In this case, the control unit 100 is a patch in which the amount of toner remaining on the intermediate transfer belt 421 is less than a predetermined standard (at least less than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameters. Then, the development parameter (development bias or development θ) is determined based on the toner amount of the patch having the smallest number of superimposed color components. For example, when forming a solid image in each of the image forming units 41Y, M, C, and K, a development parameter (development) is formed so that a toner image having the same amount of toner as patch P3 is formed on the intermediate transfer belt 421. Bias or development θ) is determined. This makes it possible to suppress transcription omission. In addition, since the development parameters are determined based on the toner amount of the patch with the smallest number of overlapping color components among the patches with less residual toner amount than the standard, wasteful toner consumption is suppressed and the paper is fixed due to the excessive toner amount. It is possible to prevent wrapping around the portion 60. However, if the determined development parameter exceeds the upper limit of the device (for example, the toner consumption is too large when developing with the development parameter, the paper is wrapped around the fixing unit 60, etc.), the upper limit of the development parameter is used. A value in the range not exceeding is determined as a development parameter.

As shown in FIG. 8, when the embossed paper EP3 having a shallower recess than the embossed paper EP2 is used as the paper, the patches P2 to P4 having two or more overlapping color components are transferred to the recesses of the embossed paper EP3. However, for the patch P1 in which the number of overlapping color components is one, an air layer is formed between the recess of the embossed paper EP3 and the toner of the patch, so that the toner is not transferred to the recess of the embossed paper EP3 and is intermediately transferred. It remains as residual toner on the belt 421. That is, all patches P1 are detected as residual toner, and patches P2 to P4 are detected with a small amount of residual toner, or the amount of residual toner becomes zero. In this case, the control unit 100 is a patch in which the amount of toner remaining on the intermediate transfer belt 421 is less than a predetermined standard (at least less than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameters. Then, the development parameter (development bias or development θ) is determined based on the toner amount of the patch having the smallest number of superimposed color components. For example, when forming a solid image in each of the image forming units 41Y, M, C, and K, a development parameter (development) is formed so that a toner image having the same amount of toner as patch P2 is formed on the intermediate transfer belt 421. Bias or development θ) is determined. This makes it possible to suppress transcription omission. In addition, since the development parameters are determined based on the toner amount of the patch with the smallest number of overlapping color components among the patches with less residual toner amount than the standard, wasteful toner consumption is suppressed and the paper is fixed due to the excessive toner amount. It is possible to prevent wrapping around the portion 60. However, if the determined development parameter exceeds the upper limit of the device (for example, the toner consumption is too large when developing with the development parameter, the paper is wrapped around the fixing unit 60, etc.), the upper limit of the development parameter is used. A value in the range not exceeding is determined as a development parameter.

Next, the control unit 100 stores the determined development parameters in association with the identification information of the selected embossed paper input tray unit, and sets the determined development parameters in the developing device 412 (step S14).

Next, the control unit 100 feeds the embossed paper from the selected paper feed tray unit, forms a plurality of patches for determining the screen pattern on the intermediate transfer belt 421 by the image forming unit 41, and causes the secondary transfer roller 424. Is transferred onto embossed paper (step S15). The plurality of patches for determining the screen pattern are a predetermined size of a predetermined image (for example, a predetermined color (which may be one color or a plurality of colors) and a predetermined gradation (which may be one gradation or a plurality of gradations)). This is a plurality of patches obtained by performing screen processing on the image) using a plurality of screen patterns stored in the storage unit 70.

Next, the control unit 100 causes the image density sensor 427 to detect the toner density of the intermediate transfer belt 421, and based on the detection result, the control unit 100 remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. The amount of residual toner is detected (step S16).

Next, the control unit 100 uses the embossed paper (embossed paper) in the job to use the screen pattern having the largest number of screen lines among the screen patterns used for the patch in which the concentration of the toner remaining on the intermediate transfer belt 421 is less than the predetermined standard. It refers to an embossed paper of the same type as the embossed paper fed in step S15, and is determined as a screen pattern to be used when forming an image on the embossed paper (not the embossed paper itself fed in step S15).
Then, the control unit 100 stores the determined screen pattern identification information in association with the identification information of the selected embossed paper feed tray unit (step S18), and ends the transferability adjustment process B.

When the start of the job is instructed, the control unit 100 determines the type of paper used for the job and the paper feed tray unit based on the setting information of the job, and the paper to be used is embossed paper. When a screen pattern and development parameters are associated with the paper feed tray unit loaded with the paper to be used, when the image processing unit 30 performs screen processing on the image data of the job, the screen is used for the screen. Have the treatment applied. Further, when the photoconductor drum 413 develops the toner image based on the job by the developing apparatus 412, the developing parameters are set in the developing apparatus 412 to perform the development.

For example, when loading paper such as plain paper having no unevenness on the surface into the paper feed tray unit loaded with embossed paper, the operation unit 22 selects and loads the corresponding paper feed tray unit. When plain paper is set as the selected paper, the control unit 100 stores information about the paper (paper of paper) stored in the storage unit 70 in association with the identification information of the selected paper feed tray unit. Seeds, basis weight, paper size, etc.) are updated. Delete the screen pattern information and development parameters to be used.

As described above, according to the second embodiment, first, the control unit 100 forms a plurality of patches having different numbers of superimposed color components on the intermediate transfer belt 421 by the image forming unit 41 for determining the development parameters. After transferring onto the selected embossed paper, the amount of residual toner remaining on the intermediate transfer belt 421 is based on the amount of toner in the patch with the smallest number of overlapping color components in the patch with less than a predetermined standard. Then, the development parameters used when forming an image on the embossed paper are determined, and the determined development parameters are set in the developing apparatus 412. Next, the control unit 100 forms a plurality of patches generated using the plurality of screen patterns on the intermediate transfer belt 421 by the image forming unit 41, transfers them onto the embossed paper fed, and then transfers the intermediate transfer belt 421. The screen pattern having the largest number of screen lines among the screen patterns used to generate a patch in which the amount of residual toner remaining in the embossed paper is less than a predetermined standard is determined as the screen pattern used when forming an image on the embossed paper. ..

Therefore, first, the development parameters that can suppress transfer omission while suppressing wasteful toner consumption and wrapping around the paper fixing portion 60 when an image is formed on embossed paper are determined, and then the determined development parameters are determined. Since the screen pattern that can suppress image quality deterioration such as transfer omission and deterioration of graininess of the image formed on the embossed paper when the image is formed on the embossed paper is determined, the unevenness of the paper surface is detected. It is possible to suppress image quality deterioration such as transfer omission and deterioration of graininess of the image formed on the embossed paper with higher accuracy without using a special sensor for the purpose.

It should be noted that the description content in the above-described embodiment is a preferable example of the present invention, and is not limited thereto.

For example, in the above embodiment, in the image forming apparatus for forming an image on paper, a case where a screen pattern and development parameters for forming an image on embossed paper are determined has been described as an example, but an image is formed by the image forming apparatus. The recording medium used at the time is not limited to paper but may be cloth or the like, and the uneven recording medium is not limited to embossed paper and may be a cloth or the like having irregularities formed on the surface.

Further, for example, in the above-described embodiment, the screen pattern determining means, the control unit 100 as the developing parameter determining means, the storage unit 70 as the storage means for storing a plurality of screen patterns, the image forming unit 40, and the like form one image. Although described as the configuration provided inside the device 1, the configuration may be provided in a plurality of devices connected via a communication network.

Further, in the above embodiment, it has been described that the transferability adjustment process A and the transferability adjustment process B are performed in advance using the embossed paper used for the job before the job is executed. However, when the job is started. In addition, the control unit 100 determines whether or not the paper used in the job is embossed paper, and if it is embossed paper, the above-mentioned transferability adjustment process A or transferability adjustment process B is automatically executed. , You may execute the job after deciding the screen pattern and development parameters to be used. As a result, the transferability adjustment process A or the transferability adjustment process B is automatically executed at the start of the job, so that the convenience of the user can be improved. Further, the screen pattern and the development parameters determined by the transferability adjustment process A or the transferability adjustment process B executed at the start of the job are stored in association with the identification information of the paper feed tray unit that feeds the embossed paper. When the job is stored in the storage unit 70 and the same embossed paper is used, the transferability adjustment process A or the transferability adjustment process B is omitted, and the screen pattern and development parameters stored in the storage unit 70 are stored. It may be used to execute a job.

Further, in the above description, an example in which a non-volatile memory, a hard disk, or the like is used as a computer-readable medium for the program according to the present invention has been disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. Further, a carrier wave is also applied as a medium for providing the data of the program according to the present invention via a communication line.

In addition, the detailed configuration and detailed operation of the image forming apparatus can be appropriately changed without departing from the spirit of the present invention.

1 Image forming device 100 Control unit 10 Image reading unit 20 Operation display unit 30 Image processing unit 40 Image forming unit 412 Developing device 412a Development sleeve 413 Photoreceptor drum 421 Intermediate transfer belt 427 Image density sensor 50 Paper transport unit 60 Fixing unit 70 Storage Department 80 Communication Department

Claims (8)

In an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A storage means for storing multiple different screen patterns,
A detection means for detecting the amount of residual toner remaining on the image carrier after transfer, and
A plurality of patches generated by using a plurality of screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of an uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of residual toner amounts of the plurality of patches are detected based on the detected residual toner amount of each of the plurality of patches. A screen pattern determining means for determining a screen pattern used for screen processing when forming an image on the uneven recording medium from among the screen patterns.
An image forming apparatus. The screen pattern determining means uses the screen pattern having the largest number of screen lines among the screen patterns used to generate the patches having a residual toner amount less than a predetermined standard among the plurality of patches as the uneven recording medium. The image forming apparatus according to claim 1, which is determined as a screen pattern used when forming an image. The image forming apparatus forms a toner image on the photoconductor for each color component by the developing device for each color component, and the toner image formed on the photoconductor for each color component is used as an intermediate as the image carrier. The image forming apparatus according to claim 1 or 2, wherein the toner image transferred to the intermediate transfer body is transferred to a recording medium after being sequentially stacked and transferred onto the transfer body. After forming a plurality of patches having different numbers of stacked color components on the intermediate transfer body and transferring the plurality of patches formed on the intermediate transfer body to the uneven recording medium, the patch remaining on the intermediate transfer body. The developing apparatus used for detecting the residual toner amount of each of the plurality of patches by the detection means and forming an image on the uneven recording medium based on the detected residual toner amount of each of the plurality of patches. The image forming apparatus according to claim 3, further comprising a development parameter determining means for determining a development parameter. The development parameter determining means is based on the toner amount of the patch in which the residual toner amount in the intermediate transfer body is less than a predetermined standard among the plurality of patches and the number of superimposed color components is the smallest. The image forming apparatus according to claim 4, wherein the development parameters are determined. 4. The screen pattern determining means, when forming the plurality of patches on the image carrier, forms a plurality of patches on the image carrier using the development parameters determined by the development parameter determining means. Or the image forming apparatus according to 5. A method for determining a screen pattern in an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A plurality of patches generated by using a plurality of different screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of the uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of screens are based on the detected residual toner amount of each of the plurality of patches. A method for determining a screen pattern for determining a screen pattern used for screen processing when forming an image on the uneven recording medium from among the patterns. A computer used for an image forming apparatus that forms a toner image on an image carrier and transfers the toner image formed on the image carrier to a recording medium to form an image on the recording medium.
A plurality of patches generated by using a plurality of different screen patterns stored in the storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on the surface of the uneven recording medium. The residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection means, and the plurality of screens are based on the detected residual toner amount of each of the plurality of patches. A program for functioning as a screen pattern determining means for determining a screen pattern used for screen processing when forming an image on the uneven recording medium from among the patterns.

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