JP2019152722A - Image forming apparatus, method for determining screen pattern, and program - Google Patents

Abstract

To prevent a deterioration in image quality of an image formed on an irregular recording medium having irregularities formed on its surface, such as embossed paper, without using a special sensor for detecting irregularities on the surface of the recording medium.SOLUTION: According to an image forming apparatus 1, a control section 100 forms a plurality of patches generated by using a plurality of screen patterns on an intermediate transfer belt 421 with an image forming unit 41 and transfers the patches onto embossed paper, subsequently detects the amount of residual toner remaining on the intermediate transfer belt 421, and determines the screen pattern having the largest number of screen lines among the screen patterns used for the generation of the patches in which the detected amount of residual toner is smaller than a predetermined reference, as a screen pattern to be used in forming an image on the embossed paper.SELECTED DRAWING: Figure 3

Description

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

  Embossed paper has irregularities on the surface, and has a different texture from plain paper, and is used for printing invitations. 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, and image quality degradation such as transfer omission (white omission) as shown in FIG. 10 occurs. .

  As a technique for suppressing image quality deterioration for a recording medium having unevenness formed on the surface of embossed paper or the like, for example, in Patent Document 1, a surface shape measuring device is provided upstream of the intermediate transfer unit to provide surface unevenness on the recording paper. A technique is described in which the amount of undulation is measured, and when the undulation is large, the exposure position of the first color and the exposure position of the second color are not overlapped.

JP 2008-122627 A

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

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

In order to solve the above problems, the invention described in claim 1
In an image forming apparatus that forms a toner image on an image carrier and forms an image on the recording medium by transferring the toner image formed on the image carrier to a recording medium.
Storage means for storing a plurality of screen patterns;
Detecting means for detecting a residual toner amount remaining on the image carrier after transfer;
A concavo-convex recording medium in which a plurality of patches generated using a plurality of screen patterns stored in the storage means are formed on the image carrier, and a plurality of patches formed on the image carrier are provided with irregularities on the surface. After the transfer to the image carrier, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection unit, and the uneven recording is performed based on the detected residual toner amount of the plurality of patches. Screen pattern determining means for determining a screen pattern used when forming an image on a medium;
Is provided.

The invention according to claim 2 is the invention according to claim 1,
The screen pattern determining means selects a screen pattern having the largest number of screen lines from among the screen patterns used for generating a patch having a residual toner amount less than a predetermined reference among the plurality of patches. Are determined as screen patterns 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 uses the toner image formed on the photoconductor for each color component as an intermediate as the image carrier. The toner image transferred to the intermediate transfer member is transferred to a recording medium after sequentially transferring on the transfer member.

The invention according to claim 4 is the invention according to claim 3,
A plurality of patches having different numbers of superimposed color components are formed on the intermediate transfer member, and the plurality of patches formed on the intermediate transfer member are transferred to the concavo-convex recording medium, and then remain on the intermediate transfer member. The residual toner amount of each of the plurality of patches is detected by the detecting unit, and the developing device used when forming an image on the uneven recording medium based on the detected residual toner amount of the plurality of patches. Development parameter determination means for determining development parameters is provided.

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

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

The invention described in claim 7
A method for determining a screen pattern in an image forming apparatus that forms a toner image on an image carrier and forms the image on the recording medium by transferring the toner image formed on the image carrier to the recording medium,
A plurality of patches generated by using a plurality of screen patterns stored in a storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on a concavo-convex recording medium having a concavo-convex surface formed thereon. After the transfer, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by a detecting unit, and the uneven recording medium is detected based on the detected residual toner amount of the plurality of patches. A screen pattern used for forming an image is determined.

The program of the invention described in claim 8 is:
A computer used in an image forming apparatus that forms a toner image on an image carrier and forms an image on the recording medium by transferring the toner image formed on the image carrier to a recording medium;
A plurality of patches generated by using a plurality of screen patterns stored in a storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on a concavo-convex recording medium having a concavo-convex surface formed thereon. After the transfer, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by a detecting unit, and the uneven recording medium is detected based on the detected residual toner amount of the plurality of patches. It is made to function as a screen pattern determining means for determining a screen pattern used when forming an image.

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

1 is a diagram illustrating a schematic configuration of an image forming apparatus. 2 is a block diagram illustrating a main functional configuration of the image forming apparatus. FIG. 3 is a flowchart showing transferability adjustment processing A executed by the control unit of FIG. 2 in the first embodiment. It is a flowchart which shows the transferability adjustment process B performed by the control part of FIG. 2 in 2nd Embodiment. FIG. 5 is a diagram schematically illustrating a state of a development parameter determination patch on an intermediate transfer belt before transfer onto embossed paper. It is a figure which shows the state which transcribe | transferred the development parameter determination patch shown in FIG. 5 to the recessed part of the embossed paper with a deep recessed part. FIG. 6 is a diagram illustrating a state in which a development parameter determination patch illustrated in FIG. 5 is transferred to a concave portion of embossed paper that is shallower than the embossed surface illustrated in FIG. 6. FIG. 8 is a diagram illustrating a state in which a development parameter determination patch illustrated in FIG. 5 is transferred to a recess of embossed paper that is shallower than the emboss illustrated in FIG. 7. FIG. 6 is a diagram illustrating a state where the development parameter determination patch illustrated in FIG. 5 is transferred to plain paper without a recess. It is a figure which shows the example of the 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 the first embodiment of the present invention. FIG. 2 is a block diagram showing the main functional configuration of the image forming apparatus 1 according to the first embodiment. An image forming apparatus 1 shown in FIGS. 1 and 2 is an intermediate transfer type color image forming apparatus using electrophotographic process technology. That is, the image forming apparatus 1 sequentially superimposes toner images of Y (yellow), M (magenta), C (cyan), and K (black) color components formed on the photosensitive drum 413 on the intermediate transfer belt 421. After transferring (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 photosensitive drums 413 corresponding to the four colors of YMCK are arranged in series in the running direction of the intermediate transfer belt 421 and the respective color toner images 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 the like. A 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 out a program corresponding to the processing content from the ROM 102 and 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 developed program. For example, when image data of a job is input from the image reading unit 10 or the communication unit 80, the control unit 100 executes the job, controls the operation of each block, and applies the paper based on the input image data. Form an image. In addition, the control unit 100 executes various processes including a transferability adjustment process A, which will be described later, in response to a user operation.
The control unit 100 functions as a screen pattern determination unit and a development parameter determination unit.

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

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

  The operation display unit 20 is configured by, for example, a liquid crystal display (LCD) 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 in accordance with 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. Based on the image data subjected to these processes, the image forming unit 40 forms an image on a sheet.

  The image forming unit 40 is based on the input image data that has undergone image processing, and the image forming units 41Y, 41M, 41C, 41K, and the like are configured to form an image using each color toner of Y component, M component, C component, and K component. An intermediate transfer unit 42 and the like are provided.

  The Y component, M component, C component, and K component image forming units 41Y, 41M, 41C, and 41K have the same configuration. For convenience of illustration and explanation, common constituent elements are denoted by the same reference numerals, and Y, M, C, or K are added to the reference numerals when distinguished from each other. In FIG. 1, only the components of the Y-component image forming unit 41Y are denoted by reference numerals, and the constituent elements of the other image forming units 41M, 41C, and 41K are omitted.

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

  A photosensitive drum (photosensitive member) 413 is formed by forming an undercoat layer (UCL), a charge generation layer on a peripheral surface of an aluminum conductive cylinder (aluminum base tube) having a drum diameter of 80 [mm], for example. This is a negatively charged organic photoconductor (OPC) in which (CGL: Charge Generation Layer) and a charge transport layer (CTL) are sequentially stacked. The charge generation layer is made of an organic semiconductor in which a charge generation material (for example, phthalocyanine pigment) is dispersed in a resin binder (for example, polycarbonate), and generates a pair of positive charges and negative charges by exposure by the exposure device 411. The charge transport layer consists of a material in which a hole transport material (electron donating nitrogen-containing compound) is dispersed in a resin binder (for example, polycarbonate resin), and transports positive charges generated in the charge generation layer to the surface of the charge transport layer. To do.

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

  The charging device 414 uniformly charges the surface of the photoconductive drum 413 to a negative polarity. The exposure device 411 is composed of, for example, a semiconductor laser, and irradiates the photosensitive drum 413 with laser light corresponding to the image of each color component. A positive charge is generated in the charge generation layer of the photosensitive drum 413 and is transported to the surface of the charge transport layer, whereby the surface charge (negative charge) of the photosensitive drum 413 is neutralized. An electrostatic latent image of each color component is formed on the surface of the photosensitive drum 413 due to a potential difference from the surroundings.

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

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

  The intermediate transfer unit 42 includes an intermediate transfer belt (intermediate transfer member) 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 an endless belt, and is stretched around a plurality of support rollers 423 in a loop shape. At least one of the plurality of support rollers 423 is configured by a driving roller, and the other is configured by a driven roller. For example, it is preferable that the roller 423A disposed downstream of the K component primary transfer roller 422 in the belt traveling direction is a drive roller. This makes it easy to keep the belt running speed constant in the primary transfer portion. As the driving roller 423A rotates, the intermediate transfer belt 421 travels in the direction of arrow A at a constant speed.

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

  The secondary transfer roller 424 is disposed on the outer peripheral surface side of the intermediate transfer belt 421 so as to face a roller 423B (hereinafter referred to as “backup roller 423B”) disposed on the downstream side of the driving 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 sheet.

  When the intermediate transfer belt 421 passes through the primary transfer nip, the toner images on the photoconductive drum 413 are primarily transferred onto the intermediate transfer belt 421 in sequence. Specifically, a primary transfer bias is applied to the primary transfer roller 422, and an electric charge having a polarity opposite to that of the toner is applied to the back side of the intermediate transfer belt 421 (the side in contact with the primary transfer roller 422). It is electrostatically transferred to the intermediate transfer belt 421.

  Thereafter, when the sheet passes through the secondary transfer nip, the toner image on the intermediate transfer belt 421 is secondarily transferred to the sheet. Specifically, by applying a secondary transfer bias to the secondary transfer roller 424 and applying a charge having a polarity opposite to that of the toner to the back side of the paper (the side in contact with the secondary transfer roller 424), the toner image becomes It is electrostatically transferred to the paper. The sheet on which the toner image has been transferred is conveyed toward the fixing unit 60.

  The belt cleaning device 426 includes a belt cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 421 and removes 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 (so-called belt-type secondary transfer unit) in which a secondary transfer belt is looped around a plurality of support rollers including the secondary transfer roller is adopted. Also good.

  An image density sensor 427 is provided on the outer peripheral surface side of the intermediate transfer belt 421 and downstream of the secondary transfer roller 424 in the belt traveling direction. The image density sensor 427 is a sensor that detects the toner density of the patch formed on the intermediate transfer belt 421 and outputs the detected toner density to the control unit 100 in order to determine the maximum density. 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 a transferability adjustment process described later. Output to the controller 100. The control unit 100 detects the residual toner amount of each patch based on the density of the toner remaining on 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 fixes the toner image on the sheet by secondarily transferring the toner image and heating and pressurizing the conveyed sheet at the fixing nip.

  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 conveyance path unit 53 includes a plurality of conveyance roller pairs such as registration roller pairs 53a.

  The sheets stored in the sheet feed tray units 51 a to 51 c are sent one by one from the top and are conveyed to the image forming unit 40 by the conveyance path unit 53. At this time, the inclination of the fed paper is corrected and the conveyance timing is adjusted by the registration roller portion in which the registration roller pair 53a is provided. Then, in the image forming unit 40, the toner image on the intermediate transfer belt 421 is secondarily transferred to one side of the sheet all at once, and a fixing process is performed in the fixing unit 60. The paper on which the image has been formed is discharged out of the apparatus by a paper discharge unit 52 having a paper discharge roller 52a.

  The storage unit 70 is configured by, for example, a nonvolatile 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, the storage unit 70 stores a plurality of screen patterns having different angles, line numbers, and the like in association with screen pattern identification information. Further, in the storage unit 70, information (paper type, basis weight, paper size, used) regarding paper loaded in the paper feed tray unit in association with the identification information of each of the paper feed tray units 51a to 51c. Screen pattern, 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 WAN (Wide Area Network). Send and receive various data.

Next, the operation in the first embodiment will be described.
FIG. 3 is executed when a paper feed tray unit (any one of the paper feed tray units 51a to 51c) is selected by the operation unit 22 and embossed paper is set as loaded paper in the first embodiment. 10 is a flowchart showing a flow of transferability adjustment processing A. The transferability adjustment process A shown in FIG. 3 is executed in cooperation with the CPU 101 of the control unit 100 and a program stored in the ROM 102.

  First, the control unit 100 feeds embossed paper from the selected paper feed tray unit, and performs a predetermined gradation (one gradation) of a predetermined image (for example, a predetermined color (which may be one color or a plurality of colors)). However, a plurality of patches generated by performing screen processing using a plurality of screen patterns stored in the storage unit 70 on an image having a predetermined size (which may be a plurality of gradations) may be intermediated by the image forming unit 41. The toner image 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 patch remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. A residual toner amount is detected (step S2).

  Next, the control unit 100 supplies the screen pattern having the largest number of screen lines among the screen patterns used for generating a patch having a residual toner amount less than a predetermined reference to the embossed paper (step S1) in the job. It is determined as a screen pattern to be used when an image is formed on the embossed paper of the same type as the embossed paper that has been printed (not the embossed paper itself fed in step S1) (step S3).

  Here, it is considered effective to select a screen pattern with a small number of isolated points and a small number of lines in order to suppress transfer omission on embossed paper with a rough surface. Deteriorates. Therefore, the screen pattern with the largest number of screen lines among the screen patterns used for generating patches with a residual toner amount less than a predetermined standard when transferred to the embossed paper is printed on the embossed paper in the job. It is determined as a screen pattern used when forming. As a result, an optimal screen pattern in which transfer omission is suppressed and deterioration of graininess is suppressed can be determined as a screen pattern used when an image is formed on the embossed paper in a 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 feed tray unit (step S4), and the transferability adjustment processing A is performed. finish.

  When the start of the job is instructed, the control unit 100 discriminates the type of paper used in the job and the paper feed tray unit based on the job setting information, the paper used is embossed paper, and the storage unit 70 When the screen pattern identification information 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. Screen processing is performed on the image data.

  Note that, for example, when loading a sheet of paper that has no embossed paper such as plain paper into the paper feed tray unit that has been loaded with embossed paper, the operation unit 22 selects the corresponding paper feed tray unit and loads it. When plain paper is set as the finished paper, the control unit 100 stores information relating to the paper stored in the storage unit 70 in association with the identification information of the selected paper feed tray unit (paper paper). Type, basis weight, paper size, etc.). Delete the screen pattern information to be used.

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

  In the first embodiment, the case where the present invention is applied to a color image forming apparatus has been described as an example. However, 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 photosensitive drum on the downstream side of the nip portion with the transfer roller in the rotation direction of the photosensitive 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 photosensitive drum, transfers the patches onto the embossed paper, and then determines the amount of toner remaining on the photosensitive drum for each patch. The screen pattern used when forming the image on the embossed paper with the screen pattern having the largest number of screen lines among the screen patterns used for creating the patch with the detected residual toner amount smaller than a predetermined reference. Determine as. As a result, even in a monochrome image forming apparatus, it is possible to select an optimum screen pattern for embossed paper to be used without using a special sensor for detecting unevenness of the paper surface, and transfer omission and graininess can be selected. Image quality deterioration such as deterioration can be suppressed.

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

  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 will be used and the operation of the second embodiment will be described below.

  In FIG. 4, in the second embodiment, a paper feed tray unit (any of the paper feed tray units 51 a to 51 c) is selected by the user's operation of the operation unit 22, and embossed paper is set as loaded paper. 6 is a flowchart showing a flow of transferability adjustment processing B executed at this time. The transferability adjustment process B shown in FIG. 4 is executed in cooperation with the CPU 101 of the control unit 100 and a program stored in the ROM 102.

First, the control unit 100 feeds embossed paper from the selected paper feed tray unit, causes the image forming unit 41 to form a plurality of patches for determining development parameters on the intermediate transfer belt 421, and the secondary transfer roller 424. Thus, the image is transferred onto the fed embossed paper (step S11).
The plurality of patches for determining development parameters are a plurality of patches with different numbers of superimposed color components. For example, a patch P1 of a solid image of Y1 color, a patch P2 of which a solid image of YM2 color is superimposed, a patch P3 of which a solid image of YMC3 color is superimposed, and a patch P4 of which a solid image of YMCK4 color is superimposed (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 patch remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. The residual toner amount 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 smaller than a predetermined reference among a plurality of patches for determining development parameters, and the number of superimposed color components is the smallest. When the image is formed on the embossed paper in the job (refers to the embossed paper of the same type as the embossed paper fed in step S11, not the embossed paper itself fed in step S11) in the job. Development parameters are determined (step S13).

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

  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 YMCK4 colors are superimposed is transferred to the recesses of the embossed paper EP1, and the number of superimposed color components is three colors. In the following patches P1 to P3, an air layer is formed between the concave portion of the embossed paper EP1 and the toner on the patch, so that the toner is not transferred to the concave portion of the embossed paper EP1 and remains as residual toner on the intermediate transfer belt 421. End up. That is, the patches P1 to P3 are all detected as residual toner, and the patch P4 detects a slight residual toner or the residual toner amount becomes zero. In this case, the control unit 100 uses a patch in which the residual toner amount remaining on the intermediate transfer belt 421 is smaller than a predetermined reference (at least smaller than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameter. 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, in FIG. 6, when a solid image is formed in each of the image forming units 41 </ b> Y, 41 </ b> M, 41 </ b> K, a toner image having a toner amount equivalent to that of the patch P <b> 4 is formed on the intermediate transfer belt 421. Determine development parameters (development bias or development θ). Here, the development θ is a ratio of the rotational speed of the developing sleeve 412a to the rotational speed of the photosensitive drum 413 (the rotational speed of the developing sleeve 412a / the rotational speed of the photosensitive drum 413). Thereby, transfer omission can be suppressed. However, if the determined development parameter exceeds the upper limit of the apparatus (for example, if the development is performed with the development parameter, the toner consumption is excessive, or the paper is wound around the fixing unit 60), the upper limit of the development parameter A value within a range not exceeding the value is determined as the 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 superimposed color components are transferred to the concave portion of the embossed paper EP2. However, for the patches P1 to P2 in which the number of superimposed color components is two or less, an air layer is formed between the concave portion of the embossed paper EP2 and the toner of the patch, so that the toner is not transferred to the concave portion of the embossed paper EP2. The toner remains on the intermediate transfer belt 421 as residual toner. That is, the patches P1 to P2 are all detected as residual toner, and the patches P3 to P4 are detected with a slight residual toner, or the residual toner amount 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 smaller than a predetermined reference (at least smaller than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameter. 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, 41M, 41K, the development parameters (development) so that a toner image having a toner amount equivalent to that of the patch P3 is formed on the intermediate transfer belt 421. Determine the bias or development θ). Thereby, transfer omission can be suppressed. In addition, the development parameters are determined based on the amount of toner in the patch with the least amount of color components among the patches with a residual toner amount less than the reference, so that wasteful toner consumption is reduced and the paper is fixed due to excessive toner amount. Winding around the portion 60 can be prevented. However, if the determined development parameter exceeds the upper limit of the apparatus (for example, if the development is performed with the development parameter, the toner consumption is excessive, or the paper is wound around the fixing unit 60), the upper limit of the development parameter A value within a range not exceeding the value is determined as the development parameter.

  As shown in FIG. 8, when embossed paper EP3 having a shallower recess than embossed paper EP2 is used as the paper, patches P2 to P4 having two or more superimposed color components are transferred to the recessed portion of embossed paper EP3. However, in the patch P1 having one color component that is superimposed, an air layer is formed between the concave portion of the embossed paper EP3 and the toner of the patch, so that the toner is not transferred to the concave portion of the embossed paper EP3, and the intermediate transfer is performed. Residual toner remains on the belt 421. That is, all the patches P1 are detected as residual toner, and the patches P2 to P4 are detected with a slight residual toner, or the residual toner amount 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 smaller than a predetermined reference (at least smaller than the toner amount of the Y1 color patch) among the plurality of patches for determining the development parameter. 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, 41M, 41C, and 41K, development parameters (development) so that a toner image having a toner amount equivalent to that of the patch P2 is formed on the intermediate transfer belt 421. Determine the bias or development θ). Thereby, transfer omission can be suppressed. In addition, the development parameters are determined based on the amount of toner in the patch with the least amount of color components among the patches with a residual toner amount less than the reference, so that wasteful toner consumption is reduced and the paper is fixed due to excessive toner amount. Winding around the portion 60 can be prevented. However, if the determined development parameter exceeds the upper limit of the apparatus (for example, if the development is performed with the development parameter, the toner consumption is excessive, or the paper is wound around the fixing unit 60), the upper limit of the development parameter A value within a range not exceeding the value is determined as the development parameter.

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

  Next, the control unit 100 feeds the embossed paper from the selected paper feed tray unit, causes the image forming unit 41 to form a plurality of patches for determining the screen pattern on the intermediate transfer belt 421, and the secondary transfer roller 424. Thus, the image is transferred onto the embossed paper (step S15). A plurality of patches for determining a screen pattern is a predetermined size of a predetermined image (for example, a predetermined color (which may be one color or a plurality of colors)) (a single gradation or a plurality of gradations). Are patches obtained by performing screen processing 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 patch remains on the intermediate transfer belt 421 without being transferred to the embossed paper for each patch. The residual toner amount is detected (step S16).

Next, the control unit 100 selects the screen pattern having the largest number of screen lines from among the screen patterns used for the patch in which the density of the toner remaining on the intermediate transfer belt 421 is less than a predetermined reference, and the embossed paper ( It is determined as a screen pattern used when an image is formed on the embossed paper of the same type as the embossed paper fed in step S15 (not the embossed paper fed in step S15) (step S17).
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 processing 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 job setting information, and the paper to be used is embossed paper. When the screen pattern and the development parameters are associated with the paper feed tray unit loaded with the paper to be used, when the screen processing is performed on the image data of the job in the image processing unit 30, the screen pattern is used. Allow processing. Further, when developing the toner image based on the job on the photosensitive drum 413 by the developing device 412, the developing parameter is set in the developing device 412, and the developing is performed.

  Note that, for example, when loading a sheet of paper that has no embossed paper such as plain paper into the paper feed tray unit that has been loaded with embossed paper, the operation unit 22 selects the corresponding paper feed tray unit and loads it. When plain paper is set as the finished paper, the control unit 100 stores information relating to the paper stored in the storage unit 70 in association with the identification information of the selected paper feed tray unit (paper paper). Type, basis weight, paper size, etc.). The screen pattern information to be used and development parameters are deleted.

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

  Therefore, first, after determining development parameters that can suppress transfer omission while suppressing wasteful toner consumption and winding of the paper around the fixing unit 60 when an image is formed on embossed paper, Determines the screen pattern that can suppress image quality deterioration such as missing transfer and graininess of the image formed on the embossed paper when the image is formed on the embossed paper, so it detects irregularities on the paper surface Therefore, it is possible to suppress image quality deterioration such as transfer omission of images formed on embossed paper and deterioration of graininess with higher accuracy without using a special sensor.

  In addition, the description content in the above-mentioned embodiment is a suitable example of this invention, and is not limited to this.

  For example, in the above embodiment, an example has been described in which an image forming apparatus that forms an image on paper determines a screen pattern and development parameters for forming an image on embossed paper. However, the image forming apparatus forms an image. The recording medium used for this is not limited to paper, and may be a cloth. The uneven recording medium is not limited to embossed paper, and a cloth or the like having an uneven surface may be used.

  Further, for example, in the above-described embodiment, the control unit 100 as the screen pattern determination unit and the development parameter determination unit, the storage unit 70 as the storage unit that stores a plurality of screen patterns, the image forming unit 40, and the like form one image. The configuration provided in the device 1 has been described, but a configuration provided in a plurality of devices connected via a communication network may be employed.

  In the above-described embodiment, it is described that the transferability adjustment processing A and the transferability adjustment processing B are performed in advance using the embossed paper used for the job before the job is executed. In addition, the control unit 100 determines whether or not the paper used in the job is embossed paper. When the paper is embossed paper, the above-described transferability adjustment processing A or transferability adjustment processing B is automatically executed. Alternatively, the job may be executed after determining a screen pattern to be used and development parameters. Thereby, the transferability adjustment processing A or the transferability adjustment processing B is automatically executed at the start of the job, so that the convenience for the user can be improved. Further, the screen pattern and the development parameters determined by the transferability adjustment processing A or transferability adjustment processing B executed at the start of the job are associated with the identification information of the paper feed tray unit that has fed the embossed paper. 70, and when executing a job using the same embossed paper, the transferability adjustment processing A or the transferability adjustment processing B is omitted, and the screen pattern and development parameters stored in the storage section 70 are stored. It is good also as executing a job using.

  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 is 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. A carrier wave is also applied as a medium for providing program data according to the present invention via a communication line.

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

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Control part 10 Image reading part 20 Operation display part 30 Image processing part 40 Image forming part 412 Developing device 412a Developing sleeve 413 Photosensitive drum 421 Intermediate transfer belt 427 Image density sensor 50 Paper conveyance part 60 Fixing part 70 Memory Part 80 communication part

Claims (8)

In an image forming apparatus that forms a toner image on an image carrier and forms an image on the recording medium by transferring the toner image formed on the image carrier to a recording medium.
Storage means for storing a plurality of screen patterns;
Detecting means for detecting a residual toner amount remaining on the image carrier after transfer;
A concavo-convex recording medium in which a plurality of patches generated using a plurality of screen patterns stored in the storage means are formed on the image carrier, and a plurality of patches formed on the image carrier are provided with irregularities on the surface. After the transfer to the image carrier, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by the detection unit, and the uneven recording is performed based on the detected residual toner amount of the plurality of patches. Screen pattern determining means for determining a screen pattern used when forming an image on a medium;
An image forming apparatus comprising:   The screen pattern determining means selects a screen pattern having the largest number of screen lines from among the screen patterns used for generating a patch having a residual toner amount less than a predetermined reference among the plurality of patches. The image forming apparatus according to claim 1, wherein the image pattern is determined as a screen pattern used when an image is formed on the screen.   The image forming apparatus forms a toner image on the photoconductor for each color component by the developing device for each color component, and uses the toner image formed on the photoconductor for each color component as an intermediate as the image carrier. The image forming apparatus according to claim 1, wherein the toner image transferred to the intermediate transfer member is transferred to a recording medium after being sequentially transferred on the transfer member.   A plurality of patches having different numbers of superimposed color components are formed on the intermediate transfer member, and the plurality of patches formed on the intermediate transfer member are transferred to the concavo-convex recording medium, and then remain on the intermediate transfer member. The residual toner amount of each of the plurality of patches is detected by the detecting unit, and the developing device used when forming an image on the uneven recording medium based on the detected residual toner amount of the plurality of patches. The image forming apparatus according to claim 3, further comprising a development parameter determining unit that determines the development parameter.   The development parameter determining means is a patch in which the residual toner amount in the intermediate transfer member is smaller than a predetermined reference among the plurality of patches, and is based on the toner amount of the patch having the smallest number of superimposed color components. The image forming apparatus according to claim 4, wherein the development parameter is determined.   5. The screen pattern determination unit forms a plurality of patches on the image carrier using the development parameters determined by the development parameter determination unit when forming the plurality of patches on the image carrier. 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 forms the image on the recording medium by transferring the toner image formed on the image carrier to the recording medium,
A plurality of patches generated by using a plurality of screen patterns stored in a storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on a concavo-convex recording medium having a concavo-convex surface formed thereon. After the transfer, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by a detecting unit, and the uneven recording medium is detected based on the detected residual toner amount of the plurality of patches. A screen pattern determining method for determining a screen pattern used for forming an image. A computer used in an image forming apparatus that forms a toner image on an image carrier and forms an image on the recording medium by transferring the toner image formed on the image carrier to a recording medium;
A plurality of patches generated by using a plurality of screen patterns stored in a storage means are formed on the image carrier, and the plurality of patches formed on the image carrier are formed on a concavo-convex recording medium having a concavo-convex surface formed thereon. After the transfer, the residual toner amount of each of the plurality of patches remaining on the image carrier is detected by a detecting unit, and the uneven recording medium is detected based on the detected residual toner amount of the plurality of patches. A program for functioning as a screen pattern determining means for determining a screen pattern used for forming an image.