JP2017044940A - Data generation device, image forming apparatus and data generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data generation device, an image forming apparatus and a data generation method capable of saving white developer without spoiling discriminability of a print image.SOLUTION: A data generation device is provided with: a first developer image creation part which forms a first developer image for forming an image to be reproduced on a recording medium; a second developer image creation part which forms a second developer image for forming a substrate on the recording medium; and a calculation part which determines a second developer amount to be used for the second developer image based on a first developer amount to be used for the first developer image. An image forming apparatus is provided with a printing part which forms the first developer image and the second developer image on the recording medium. A data generation method is provided with: a first developer image creation process for forming the image to be reproduced on the recording medium; a second developer image creation process for forming the substrate on the recording medium; and a calculation process for determining the second developer image amount to be used for the second developer image based on the first developer image amount to be used for the first developer image.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a data generation apparatus, an image forming apparatus, and a data generation method.

  A conventional ink jet printer forms a base by applying a white developer on the entire surface of a medium or the entire base of a printed image (see, for example, Patent Document 1).

JP 2002-038063 A

  However, the prior art has a problem that the white developer is used wastefully because the white developer is uniformly applied even in the case of printing a medium with a light color or a dark print image on the medium. .

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a data generation apparatus, an image forming apparatus, and an image forming apparatus capable of saving white developer without impairing the discrimination of a printed image. It is to provide a data generation method.

  In order to solve the above-described problems, a data generation apparatus according to the present invention includes a first developer image creating unit that forms a first developer image for image formation transferred on a recording medium, and the recording medium. A second developer image creating unit for forming a second developer image for forming a base on the top, and the second developer based on the first developer amount used for the first developer image; And a calculating unit for determining a second developer amount used for the image.

  In addition, an image forming apparatus according to the present invention includes a first developer image creating unit that forms a first developer image for image formation transferred on a recording medium, and a base formation on the recording medium. A second developer image creating unit for forming a second developer image for the first developer image, and a second developer image used for the second developer image based on a first developer amount used for the first developer image. And a calculation unit that determines the amount of the second developer, and a printing unit that forms the first developer image and the second developer image on the recording medium.

  Furthermore, the data generation method according to the present invention includes a first developer image creating step for forming a first developer image for image formation transferred on a recording medium, and a base formation on the recording medium. A second developer image forming step for forming a second developer image for the first developer image, and a second developer image used for the second developer image based on the first developer amount used for the first developer image. And a calculating step for determining the amount of developer.

  According to the present invention, it is possible to provide a data generation apparatus, an image forming apparatus, and a data generation method that can save white developer without impairing the discrimination of a printed image.

1 is a schematic configuration diagram of a printer 1 as an image forming apparatus according to an embodiment. 2 is a block diagram illustrating a functional configuration of a printer 1 and a PC 100 connected to the printer 1. FIG. 3 is a flowchart illustrating main processing in the printer 1. It is a flowchart explaining the background creation processing in step S110 of FIG. It is a flowchart explaining the gray scale process in step S204 of FIG. The coefficients used to calculate the white density value are listed according to the type of colored paper. The relationship between the gray scale value and the white density value is shown in a graph. When printing images having different densities are formed on black paper, the difference in white density values applied to the background is illustrated. When an image of a predetermined density image is formed on paper of different colors, the difference in white density value used for the background is illustrated. It is a figure explaining the calculation process of the gray scale value in a color image. It is a figure explaining the calculation process of the gray scale value in a color image. It is a figure explaining the calculation process of the gray scale value in a color image.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

  FIG. 1 is a schematic configuration diagram of a printer 1 as an image forming apparatus according to the present embodiment. The printer 1 according to this embodiment includes an image drum unit as a developing unit corresponding to a five-color toner as a colored developer of black (K), yellow (Y), magenta (M), cyan (C), and white (W). An intermediate transfer type image forming apparatus having 4K, 4Y, 4M, 4C, and 4W (4K to 4W, hereinafter referred to as an ID unit) and capable of color printing.

  Each of the ID units 4K to 4W is provided to form a developer image and is configured to be detachable from the printer 1. The ID units 4K to 4W include photosensitive drums 7K to 7W as image carriers that form an electrostatic latent image on the surface, charging rollers 8K to 8W that uniformly and uniformly charge the surfaces of the photosensitive drums 7K to 7W, The electrostatic latent images formed on the surfaces of the photosensitive drums 7K to 7W are developed, and toner is supplied to the developing rollers 9K to 9W as developing units for forming toner images, and the developing rollers 9K to 9W. Supply rollers 10K to 10W as supply units for frictional charging are provided.

  Each of the photosensitive drums 7K to 7W includes a conductive support and a photoconductive layer. For example, a charge generation layer as a photoconductive layer and a charge transport layer are sequentially stacked on a metal shaft such as aluminum as a conductive support. It is an organic photoconductor constructed.

  The charging rollers 8K to 8W are constituted by, for example, a metal shaft and semiconductive epichlorohydrin rubber. The charging rollers 8K to 8W are in contact with the photosensitive drums 7K to 7W with a predetermined pressure, and based on a voltage applied from a high voltage power source (not shown) based on an instruction of a charging voltage control unit 342 described later, the photosensitive drums The surface of 7K to 7W is uniformly and uniformly charged.

  The developing rollers 9K to 9W are provided with, for example, urethane rubber in which carbon black is dispersed on the outer periphery of a metal shaft such as stainless steel, and the surface thereof is subjected to isocyanate treatment. The developing rollers 9K to 9W are disposed so as to be in pressure contact with the surfaces of the photosensitive drums 7K to 7W, supply toner to the electrostatic latent images formed on the photosensitive drums 7K to 7W, and develop the toner images.

  In the supply rollers 10K to 10W, a semiconductive foamed silicone sponge layer is disposed on the outer periphery of a metal shaft such as stainless steel. The supply rollers 10K to 10W are in contact with the developing rollers 9K to 9W with a predetermined pressure, and supply the frictionally charged toner to the developing rollers 9K to 9W.

  By the way, LED heads 6K to 6W as exposure units for forming electrostatic latent images on the surfaces of the photosensitive drums 7K to 7W are provided immediately above the photosensitive drums 7K to 7W. The LED heads 6K to 6W are LED heads having a light emitting element such as an LED element and a lens array, for example, and irradiation light output from the LED element based on image data forms an image on the surface of the photosensitive drums 7K to 7W. It arrange | positions so that it may become a position.

  In the present embodiment, the amount of light emitted from the LED head 6W is changed to adjust the amount of white toner in the ground to change the electrostatic latent image formed on the surface of the photosensitive drum 7W. Not limited to this, the voltage applied to any of the charging roller 8W, the developing roller 9W, and the supply roller 10W may be adjusted, or a combination of these may be used.

  The intermediate transfer belt 11 is stretched by a driving roller 12, a belt driven roller 13 and a secondary transfer backup roller 14, and is driven by the rotation of the driving roller 12. Such an intermediate transfer belt 11 is formed in a seamless endless shape and is made of a high-resistance semiconductive plastic film. The upper surface portion of the intermediate transfer belt 11 is disposed so as to be movable between the primary transfer rollers 5K to 5W and the ID units 4K to 4W.

  The primary transfer rollers 5K to 5W are disposed so as to be in pressure contact with the photosensitive drums 7K to 7W. The primary transfer rollers 5 </ b> K to 5 </ b> W transfer toner images developed on the surfaces of the photosensitive drums 7 </ b> K to 7 </ b> W based on a voltage applied from a high voltage power source (not shown) based on an instruction of a transfer voltage control unit (not shown) to the intermediate transfer belt 11. Primary transfer.

  The cleaning blade 15 is disposed in contact with a position of the intermediate transfer belt 11 facing the belt driven roller 13 and scrapes off residual toner remaining on the intermediate transfer belt 11 without being subjected to secondary transfer. Residual toner or the like scraped off by the cleaning blade 15 is accommodated in a cleaner container 16.

  The secondary transfer roller 21 is disposed to face the secondary transfer backup roller 14. The secondary transfer roller 21 secondary-transfers the toner image primarily transferred to the intermediate transfer belt 11 to the recording medium 3 based on a voltage applied from a high voltage power source (not shown) based on an instruction from a transfer voltage control unit (not shown). Transcript.

  As the recording medium 3, paper such as high-quality paper, coated paper, art paper, and recycled paper can be used. The recording medium 3 is stored in a stacked state on the paper feed cassette 2 and is fed out one by one to the transport path 32 by a hopping roller 31 provided immediately above the paper feed cassette 2. The recording medium 3 fed out to the conveyance path 32 is conveyed to a secondary transfer point formed by the intermediate transfer belt 11 and the secondary transfer roller 21 at a predetermined timing by the registration roller 18 and the conveyance roller 19.

  The fixing device 50 includes a heat roller 51 and a pressure roller 52. The heat roller 51 is formed, for example, by covering a hollow cylindrical cored bar made of aluminum or the like with a heat-resistant elastic layer of silicone rubber and coating a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) tube thereon. Is formed by. A heater (not shown) such as a halogen lamp is provided in the cored bar. The pressure roller 52 has a structure in which a heat-resistant elastic layer of silicone rubber is coated on a metal core made of aluminum or the like, and PFA is coated thereon, so that a nip portion is formed between the pressure roller 52 and the heat roller 51. It is arranged. The recording medium 3 on which the toner image is transferred at the secondary transfer point passes through a nip formed by the heat roller 51 and the pressure roller 52 maintained at a predetermined temperature, so that the toner on the recording medium 3 is transferred to the recording medium 3. Heat and pressure are applied, the toner is melted, and the toner image is fixed.

  The recording medium 3 on which the toner image is fixed is transported to the re-transport path 34 or discharged out of the apparatus by the selection operation of the transport separator 33 driven by the driving means. When the recording medium 3 is conveyed to the reconveying path 34, the recording medium 3 is conveyed by the reconveying rollers 35-1, 35-2, and 35-3 and joins the conveying path 32. On the other hand, when the recording medium 3 is discharged outside the apparatus, the recording medium 3 is discharged outside the apparatus by the discharge roller 36. The write sensor 37 and the discharge sensor 38 are mechanical sensors for detecting the passage of the recording medium 3, and operate every time the recording medium 3 passes. The detection signal output from the writing sensor 37 or the discharge sensor 38 is used, for example, at an image formation start timing or a drive start timing of the transport separator 33.

  FIG. 2 is a block diagram for explaining the functional configuration of the printer 1 and a PC (Personal Computer) 100 as an information processing apparatus connected to the printer 1.

  The PC 100 is equipped with an application 101 for a user to generate an image. The application 101 is so-called document creation software or drawing software, and generates PC creation data to be used for printing when operated by a user. When the user performs an operation to start printing, the application 101 passes the PC creation data to the printer driver 102 in order to start printing.

  The printer driver 102 is software for driving the printer 1 and converts the PC creation data acquired from the application 101 into a format that can be analyzed by the printer 1. Specifically, the printer driver 102 converts bitmap-format PC creation data generated by the application 101 into script-format PDL data expressed in a PDL (Page Description Language) format. Further, the printer driver 102 adds the paper color information input from the paper color information input unit 103 to the PDL data.

  The paper color information input unit 103 is used by a user who outputs a printed material to input paper color information including information regarding a user who receives the printed material. For example, specific examples of the paper color information input unit 103 include a keyboard and a mouse connected to the PC 100, for example. The paper color information input to the paper color information input unit 103 is the color of the paper that is the recording medium 3, and in the following, it is possible to select one of three types of “black, gray, and white”. When not selected, “white” is selected. The paper color information input to the paper color information input unit 103 is passed to the printer driver 102. The printer driver 102 adds the acquired paper color information to, for example, the header portion of the PDL data and passes it to the data transmission unit 104.

  The data transmission unit 104 transmits PDL data to the printer 1 via an interface such as an output port.

  The printer 1 includes a controller control unit 200, a process control unit 300, and an operator panel unit 400 as functional configurations.

  The controller control unit 200 includes a data receiving unit 210, a job control unit 220, a color image creation unit 230 as a first developer image creation unit, a background creation unit 240, and a storage unit 250.

  The data receiving unit 210 receives PDL data transmitted from the PC 100.

  The job control unit 220 cuts the PDL data received by the data receiving unit 210 in units of jobs and analyzes the printer job language. A typical printer job language is PJL (Printer Job Language).

  The job control unit 220 acquires a print color setting used in the present embodiment as a printer job language. If there is a white use setting designation command, the job control unit 220 notifies the white use storage unit 254 to store the setting to use white (white use setting). Further, when there is a white density value setting designation command, the job control unit 220 notifies the white density value storage unit 255 to store the white density value (white density setting). Note that the white use setting or the white density value setting is not acquired as a printer job language, but is received from the user via the white use setting unit 410 and the white density value setting unit 420 provided in the operator panel unit 400. It can also be stored in the unit 254 and the white density value storage unit 255. The printer 1 may be configured to store these setting values in advance. In this case, for example, the job control unit 220 includes a memory 220a as a setting value storage unit, and stores the white use setting or the white density value setting in the memory 220a. Thereby, the job control unit 220 does not include the white use setting or the white density value setting in the print data, and the user does not input the white use setting or the white density value setting via the operator panel unit 400. However, the processing can be continued by referring to the white use setting or the white density value setting stored in the memory 220a. Further, the job control unit 220 may be configured such that the setting value stored in the memory 220a can be changed (updated) when an input from the user is received via the operator panel unit 400. Further, the job control unit 220 gives an instruction for converting the PDL data for one job into color image data to the color image creation unit 230. During this conversion work, the PDL data is analyzed in units of pages, and converted into a data format that can be printed by the printing unit 330 described later.

  The color image creation unit 230 creates color image data as a first developer image by analyzing the PDL data based on an instruction from the job control unit 220. The created color image data is composed of 32 bits for each object, and gradation values of respective colors to be rendered for the same object are arranged at adjacent addresses. The color space used in this embodiment is, for example, a CMYK color space. In the color image data of each object, gradation values are arranged in the order of cyan (C), magenta (M), yellow (Y), and black (K). That is, 8 bits are assigned to each color, and the gradation value of each color is expressed in 256 levels from 0 to 255. The color image creation unit 230 then passes the color image data for one job to the job control unit 220. The job control unit 220 stores the acquired color image data in the color image storage unit 251.

  The background creation unit 240 includes a gray scale unit 241, a white density value calculation unit 242 serving as a calculation unit that calculates the white density value of the background based on the gray scale value and the paper color, and a second developer image creation unit. And a white image generation unit 243, and based on an instruction from the job control unit 220, the color image data stored in the color image storage unit 251 is read and white image data as a second developer image for the background is read Create

  The gray scale conversion unit 241 is a density conversion unit that converts color image data having color data into a gray scale value indicating brightness. In the present embodiment, the gray scale value is a value managed for each object having a plurality of pixels as one block. For example, the gray scale unit 241 uses the color image data stored in the color image storage unit 251 as the color data of each object as cyan (C), magenta (M), yellow (Y), and black (K). The gradation value of each component is read. Then, the gray scale conversion unit 241 calculates a gray scale value from the read gradation value. Then, the gray scale conversion unit 241 passes the calculated gray scale value to the white density value calculation unit 242, and passes information on the position of the object to the white image generation unit 243.

  The white density value calculation unit 242 calculates a white density value by multiplying the gray scale value calculated for each object by the gray scale conversion unit 241 and a coefficient determined by the paper color. A method for calculating the white density value will be described later. The white density value calculated by the white density value calculation unit 242 is described in the white density value storage unit 255 and is passed to the white image generation unit 243.

  The white image generation unit 243 sets the white density value acquired from the white density value calculation unit 242 to the object position acquired from the gray scale conversion unit 241, thereby forming the background color image data for forming the background of the color image data. As white image data is generated. This white image data is binarized image data. Then, the white image generation unit 243 passes the generated white image data to the job control unit 220. The job control unit 220 stores the acquired white image data in the white image storage unit 252.

  The storage unit 250 includes a color image storage unit 251, a white image storage unit 252, a paper color information storage unit 253, a white use storage unit 254, and a white density value storage unit 255.

  The paper color information storage unit 253 stores settings relating to the color of the printing paper as the recording medium 3 received via the paper color information input unit 103 of the PC 100.

  The white use storage unit 254 stores a white use setting as a base color use setting indicating whether or not to use a base color.

  The white density value storage unit 255 stores a white density setting indicating a white density value used for the background color.

  The process control unit 300 executes image formation on the recording medium 3 based on the white image data and color image data created by the controller control unit 200. For example, the process control unit 300 forms an image indicated by white image data on the recording medium 3 using a white color material (toner), and then converts the image indicated by the color image data to each color (cyan (C)). , Magenta (M), yellow (Y), and black (K) color materials (toners). Such a process control unit 300 includes a white image gradation conversion unit 310, a color image gradation conversion unit 320, and a printing unit 330.

  The white image gradation conversion unit 310 performs output gradation conversion so that the white image data created by the controller control unit 200 has an output resolution that can be handled by the printing unit 330.

  The color image gradation conversion unit 320 performs output gradation so that the color image data created by the controller control unit 200 has an output resolution that can be handled by the printing unit 330.

  The printing unit 330 prints the white image data that has been output tones by the white image tone conversion unit 310 and the color image data that has been output tones by the color image tone conversion unit 320.

  The print density control unit 340 includes an exposure control unit 341, a charging voltage control unit 342, a development voltage control unit 343, and a supply voltage control unit 344.

  The print density control unit 340 controls the output of each unit based on the data acquired from the white image tone conversion unit 310 and the color image tone conversion unit 320 so that the printing unit 330 can perform printing at a predetermined density. .

  The exposure control unit 341 adjusts the density of the white image data and the color image data by adjusting the exposure amount of the LED heads 6K to 6W. The exposure control unit 341 performs adjustment including density adjustment of white image data in the background portion.

  The charging voltage control unit 342 adjusts the density of white image data and color image data by adjusting the voltage applied from a high voltage power supply (not shown) to the charging rollers 8K to 8W.

  The development voltage controller 343 adjusts the density of white image data and color image data by adjusting the voltage applied from a high voltage power supply (not shown) to the development rollers 9K to 9W.

  The supply voltage control unit 344 adjusts the density of white image data and color image data by adjusting the voltage applied from a high voltage power supply (not shown) to the supply rollers 10K to 10W.

  The operator panel unit 400 includes, for example, a display device such as an LCD (Liquid Crystal Display), an input device such as a touch panel, etc., and displays device information to the user and accepts a setting input from the user. Such an operator panel unit 400 includes the white use setting unit 410 and the white density value setting unit 420 described above.

  The white usage setting unit 410 receives an input of setting for using white as a background color from the user, and causes the white usage storage unit 254 to store the received setting.

  The white density value setting unit 420 receives an input of a white density value setting as a background density value from the user, and stores the received setting in the white density value storage unit 255.

  Next, the operation of the printer 1 according to this embodiment will be described. FIG. 3 is a flowchart for explaining main processing in the printer 1.

  First, in step S101, the data receiving unit 210 receives PDL data that is print data. The PDL data is transmitted from the PC 100. Then, the data receiving unit 210 passes the received PDL data to the job control unit 220.

  The job control unit 220 confirms whether or not the paper color is colored paper in the acquired PDL data. Specifically, the job control unit 220 analyzes the printer job language included in the PDL data and confirms whether or not colored paper is used (whether or not colored paper is selected by the printer driver 102). If color paper is used (Yes in step S102), the processing by the job control unit 220 proceeds to step S103. On the other hand, if blank paper is used (No in step S102), the processing by the job control unit 220 proceeds to step S105.

  In step S <b> 103, the job control unit 220 gives an instruction to read the setting value of the predetermined color stored in the paper color information storage unit 253. This set value is used to calculate the white density value of the background, and the set value will be described later.

  Next, the job control unit 220 notifies the white use storage unit 254 of a white use instruction, that is, a background formation instruction. The white use storage unit 254 that has received the notification stores the white use setting for using white (step S104).

  The white use setting can be included in the PDL data as print data as setting information for each print job. However, as described above, the printer job language included in the PDL data can be stored in advance in the memory 220a as a device setting or can be stored by the user via the operator panel unit 400, as described above. Can be set.

  In step S <b> 105, the job control unit 220 passes the acquired PDL data to the color image creation unit 230 and starts editing processing. The color image creation unit 230 analyzes the page description language, starts editing processing such as graphic information, character information, and image information for each page, and executes editing processing for one page (step S106).

  Then, the color image creation unit 230 creates color image data based on the edited information (step S107). The color image data as a creation result is image data of 256 gradations expressed as a color space with the CMYK color model. One pixel of image data having 256 gradations is expressed by 1 byte (8 bits). Furthermore, in the case of the CMYK color model, the number of bits per pixel is quadrupled, and one pixel is represented by 4 bits (32 bits). Here, since one pixel of the normal color image data is in the 32-bit pack format as described above, the gradation value of each color in the same pixel is arranged at an adjacent address. The gray scale unit 241 calculates a gray scale value from the pixel value of each pixel of the color image data. In addition, the background creation unit 240 creates white image data from the gray scale value calculated by the gray scale conversion unit 241. Then, when the creation of the color image data is completed, the color image creation unit 20 passes the created color image data to the job control unit 220.

  The job control unit 220 stores the color image data acquired from the color image creation unit 230 in the color image storage unit 251 (step S108).

  Next, the job control unit 220 acquires a set value of a predetermined color stored in the paper color information storage unit 253, and determines whether or not the background white printing is possible. If the acquired setting value of the predetermined color indicates white, that is, it is a background creation instruction (Yes in step S109), the job control unit 220 notifies the background creation unit 240 to that effect. Upon receiving the notification, the background creation unit 240 executes white processing to create white image data (step S110). The background creation processing by the background creation unit 240 will be described later. On the other hand, when the acquired setting value of the predetermined color does not indicate white (No in step S109), the process by the job control unit 220 proceeds to step S111.

  In step S <b> 111, the job control unit 220 passes the color image data stored in the color image storage unit 251 to the process control unit 300 to execute image formation. For example, the process control unit 300 converts the color image data acquired by the color image gradation conversion unit 141 into an output gradation. Then, the color image tone conversion unit 141 passes the tone-converted color image data to the printing unit 330.

  Here, the printing unit 330 has a background creation instruction (Yes in Step 109), and when the background creation processing is performed, based on the white image data subjected to gradation conversion and the color image data subjected to gradation conversion. Thus, printing on the recording medium 3 is executed. On the other hand, when there is no background creation instruction (No in step S109) and the background creation processing is not performed, the printing unit 330 executes printing on the recording medium 3 based on the color image data subjected to gradation conversion. .

  The job control unit 220 determines whether the editing process by the color image creation unit 230 has been completed for all pages. When the editing process has been completed for all pages (Yes in step S112), the series of processes is terminated. On the other hand, if the editing process has not been completed for all pages (No in step S112), in other words, if there is a page for which the editing process by the background creation unit 240 has not been completed, the process by the job control unit 220 proceeds to step S106. Return.

  FIG. 4 is a flowchart illustrating the background creation processing in step S110 of FIG.

  First, the job control unit 220 notifies the background creation unit 240 of the storage location of the color image data (step S201). At this time, the job control unit 220 creates a white image template having the same pixel arrangement as that of the color image data (for example, the number of pixels in the vertical and horizontal directions), and passes the template to the background generation unit 240. And

  In response to the read instruction in step S103 in FIG. 3, the gray scale unit 241 in the background creation unit 240 obtains coefficients (inclination: A, intercept: B) for calculating the density value of the white toner used for the background. (Step S202).

  Then, the gray scale conversion unit 241 acquires pixel values in units of objects from the color image data stored in the storage location notified from the job control unit 220 in the color image storage unit 251. As described above, the pixel value for one pixel is expressed in the 32-bit pack format. Accordingly, in step S202, the gray scale converting unit 241 extracts the gradation values of each color (here, cyan, magenta, yellow, and black) from 8 bits from the 32-bit pack format pixel information (step 203).

  Next, the gray scale conversion unit 241 executes a gray scale process (step S204). Note that the gray scale processing is processing for converting each acquired pixel value into a gray scale value. In addition, the gray scale conversion unit 241 passes information indicating the pixel position from which the pixel value is acquired and the gray scale value converted from the pixel value to the white density value calculation unit 242. The gray scale process will be described later.

  The white density value calculation unit 242 acquires the grayscale value (X) calculated in the grayscale processing (step S205), the coefficients A and B acquired in step S202, and the grayscale value acquired in step S205 ( A white density value D [%] is calculated from X) (step S206). A method for calculating the white density value D [%] will be described later.

  Then, the background creation unit 240 determines whether or not grayscale processing has been completed for all objects of the color image data. If the gray scale processing has been completed for all objects (Yes in step S207), the processing by the background creation unit 240 proceeds to step S208. On the other hand, if the grayscale processing has not been completed for all the objects (No in step S207), in other words, if there is an object for which grayscale processing has not been completed, the processing by the background creation unit 240 proceeds to step S203. Return. Here, when the process returns to step S203, the grayscale conversion unit 241 acquires the pixel value of an object that has not yet been subjected to the grayscale process.

  In step S <b> 208, the background creation unit 240 passes the generated white image data to the job control unit 220. The job control unit 220 stores the white image data in the white image storage unit 252 and passes it to the process control unit 300 for image formation. For example, the process control unit 300 performs tone conversion of the white image data acquired by the white image tone conversion unit 310 into an output tone (step S209). Then, the white image gradation conversion unit 310 passes the gradation-converted white image data to the printing unit 330. Note that the printing unit 330 starts printing when the color image data and the white image data are prepared in step S111 of FIG.

  FIG. 5 is a flowchart for explaining the gray scale processing in step S204 of FIG.

  The gray scale conversion unit 241 averages the cyan, magenta, yellow, and black tone values of the pixels extracted in step S203 of FIG. A tone value, a yellow average gradation value, and a black average gradation value are defined (step S301).

  The gray scale conversion unit 241 multiplies the cyan average gradation defined in step S301 by a preset cyan gray scale factor value to calculate a cyan gray scale value (step S302).

  The gray scale conversion unit 241 multiplies the magenta average gradation defined in step S301 by a preset magenta gray scale coefficient value to calculate a magenta gray scale value (step S303).

  The gray scale conversion unit 241 multiplies the yellow average gradation defined in step S301 by a preset yellow gray scale factor value to calculate a yellow gray scale value (step S304).

  Next, the gray scale converting unit 241 defines the cyan gray scale value calculated in step S302, the magenta gray scale value calculated in step S303, the yellow gray scale value calculated in step S304, and the definition in step S301. The gray scale value is calculated as the sum of the average black gradation value. Then, the gray scale conversion unit 241 stores the calculated gray scale value and information indicating the pixel position from which the pixel value used when calculating the gray scale value is acquired in the white density value storage unit 255 (step S305). ). A detailed method for calculating the gray scale value will be described later.

  FIG. 6 is a list of coefficients used for calculating the white density value for each type of colored paper. As described above, there are two types of coefficients, slope A [% / level] and intercept B [%], and these coefficients are applied when calculating the white density value used for the background of colored paper. The coefficient is stored in advance in the paper color information storage unit 253 for each type of colored paper. Here, when “white paper” is selected as the paper, white is used as the background (A = 0, B = 0), while “black paper” and “gray paper” are selected as the paper. In such a case, a coefficient for using white for the background is used. In the present invention, when a predetermined print image is printed on colored paper, the darker colored paper has a concept of increasing the white density value of the background so that the coefficients A and B both satisfy “black paper”> “gray paper”. It has become a value.

  FIG. 7 is a graph showing the relationship between the gray scale value and the white density value. As shown in FIG. 7, the white density value Y is represented by a straight line graph having a slope −A, an intercept B, and a gray scale value (X). Here, the values shown in FIG. 6 are applied to the inclination −A and the intercept B. Further, in the present invention, when a predetermined print image is printed on colored paper, the idea is that the lower the density of the print image, the darker the white density value of the background. For example, when the density of the printed image is extremely light (X = 0), the white density value used for the background is maximum (A [%]), and when the density of the printed image is extremely high (X = 255), the background The white density value is not applied to.

FIG. 8 illustrates the difference in white density values applied to the background when forming printed images (objects 1 to 3) having different densities on black paper. Here, since the paper as the recording medium 3 is black paper, the coefficients shown in FIG. 6 are read from the paper color information storage unit 253 as the coefficients (A, B) for calculating the white density value.
A [% / level] = B / 255 = 0.392 [% / level], B [%] = 100 [%]

(1) When the object 1 is printed on black paper, the white density value of the background of the formed print image (print image 1) is calculated as follows.
The gray scale value (X) of the object 1 is referred to the value shown in FIG.
Gray scale value (X): 8
Background white density value (D): D = −0.392 × 8 + 100 = 96.9 [%]
(2) When the object 2 is printed on black paper, the white density value of the background of the formed print image (print image 2) is calculated as follows.
The gray scale value (X) of the object 2 is referred to the value shown in FIG.
Gray scale value (X): 26
Background white density value (D): D = −0.392 × 26 + 100 = 89.8 [%]
(3) When the object 3 is printed on black paper, the white density value of the background of the formed print image (print image 3) is calculated as follows.
The gray scale value (X) of the object 3 is referred to a value shown in FIG.
Gray scale value (X): 226
Background white density value (D): D = −0.392 × 226 + 100 = 11.4 [%]

FIG. 9 illustrates the difference in white density values used for the background when forming an image of a predetermined density image (object 1) on papers of different colors (black paper, gray paper, white paper).
(4) When the object 1 is printed on gray paper, the white density value of the background of the formed print image (print image 4) is calculated as follows.
Since the paper as the recording medium 3 is gray paper, the coefficients (A, B) for calculating the white density value are read from the paper color information storage unit 253 as shown in FIG.
A [% / level] = B / 255 = 0.196 [% / level], B [%] = 50 [%]
The gray scale value (X) of the object 1 is referred to the value shown in FIG.
Gray scale value (X): 8
Background white density value (D): D = −0.196 × 8 + 50 = 48.4 [%]
(5) When printing the object 1 on white paper, the white density value of the background of the printed image (printed image 5) to be formed is calculated as follows.
Since the sheet as the recording medium 3 is a blank sheet, the coefficients (A, B) for calculating the white density value are read from the sheet color information storage unit 253 as shown in FIG.
The gray scale value (X) of the object 1 is referred to the value shown in FIG.
Gray scale value (X): 8
Background white density value (D): D = 0 × 8 + 0 = 0 [%]

  10, FIG. 11 and FIG. 12 illustrate the process of calculating the gray scale values in the color images (objects 1 to 3).

The color images (objects 1 to 3) use the color images with different densities shown in FIG.
In calculating the gray scale value, the following equation is used.
GV = CV × CC + MV × MC + YV × YC + KV
However, GV is a gray scale value. CV is a cyan gradation value, and CC is a cyan gray scale factor value, which is “0.2988” in this example. MV is a magenta tone value, and MC is a magenta gray scale factor value, which is “0.5868” here. YV is a gradation value of yellow, and YC is a gray scale factor value of yellow, which is “0.1144” here. KV is a black gradation value.
The gray scale factor values for cyan, magenta and yellow are numerical values used in the NTSC weighted average method. These gray scale coefficient values are weighting coefficient values, and may be changed in consideration of the toner characteristics of each color. In the present embodiment, the form in which the gray scale value is calculated using the above formula has been described. However, the form in which the gray scale value is calculated by another method may be used. In this case, for example, the gray scale value can be calculated by a simple average method, an intermediate value method, or a weighted average and correction method using HDTV coefficients.

An example of calculating the gray scale values of the objects 1 to 3 to which the above formula is applied is as follows.
Object 1
GV = 0.29888 × 0.1 × 255≈8
Object 2
GV = 0.29888 × 1 × 255 + 0.5868 × 1 × 255≈226
Object 3
GV = 0.29888 × 0.1 × 255 + 0.5868 × 0.1 × 255 + 0.1144 × 0.1 × 255≈26

  As described above, according to the present embodiment, printing is performed by changing the amount of white toner (white density value) for forming the background in accordance with the medium information and the density of the print image. White toner can be saved without loss.

  In the description of the present embodiment, the case where the color of the recording medium is used as a reference is described. However, not only the color of the recording medium but also the density value such as optical density (OD value) and the shape such as surface roughness are used. The developer amount may be changed. Further, the amount of each developer may be changed according to the information on the recording medium acquired through a scanner or the like.

  Further, the background white density value control according to the present embodiment is performed in units of objects taking an average of a plurality of pixels due to processing speed and LED head exposure control restrictions, but may be controlled in units of pixels.

DESCRIPTION OF SYMBOLS 1 Printer 2 Paper feed cassette 3 Recording medium 4K-4W Image drum unit 5K-5W Primary transfer roller 6K-6W LED head 7K-7W Photosensitive drum 8K-8W Charging roller 9K-9W Developing roller 10K-10W Supply roller 11 Intermediate transfer belt 12 Driving roller 13 Belt driven roller 14 Secondary transfer backup roller 15 Cleaning blade 16 Cleaner container 18 Registration roller 19 Transport roller 21 Secondary transfer roller 32 Transport path 33 Transport separator 34 Re-transport path 35-1, 35-2, 35- 3 Re-transport roller 36 Discharge roller 37 Write sensor 38 Discharge sensor 50 Fixing device 51 Heat roller 52 Pressure roller 100 PC
DESCRIPTION OF SYMBOLS 101 Application 102 Printer driver 103 Paper color information input part 104 Data transmission part 200 Controller control part 210 Data reception part 220 Job control part 230 Color image creation part 240 Background creation part 241 Gray scale conversion part 242 White density value calculation part 243 White image Generation unit 250 Storage unit 251 Color image storage unit 252 White image storage unit 253 Paper color information storage unit 254 White use storage unit 255 White density value storage unit 300 Process control unit 310 White image gradation conversion unit 320 Color image gradation conversion unit 330 Printing Unit 340 Print Density Control Unit 341 Exposure Control Unit 342 Charging Voltage Control Unit 343 Development Voltage Control Unit 344 Supply Voltage Control Unit 400 Operator Panel Unit 410 White Use Setting Unit 420 White Density Value Setting Unit

Claims (15)

A first developer image creating unit for forming a first developer image for image formation transferred on a recording medium;
A second developer image creating unit for forming a second developer image for forming a base on the recording medium;
A data generation device comprising: a calculation unit that determines a second developer amount used for the second developer image based on a first developer amount used for the first developer image. . The data generation apparatus according to claim 1, wherein the calculation unit determines the second developer amount according to a type of the recording medium. The data generation apparatus according to claim 2, wherein the calculation unit determines the second developer amount using a density coefficient that is set in advance according to a type of the recording medium. 4. The data generation according to claim 3, wherein the calculation unit determines the second developer amount by using a gray scale value obtained from the first developer image and the density coefficient. apparatus. The data generation apparatus according to any one of claims 2 to 4, wherein the type of the recording medium is classified based on a color. 6. The data generation apparatus according to claim 1, wherein the second developer image has higher brightness than the first developer image. 7. The data generation apparatus according to any one of claims 1 to 6, wherein the second developer is white. A first developer image creating unit for forming a first developer image for image formation transferred on a recording medium;
A second developer image creating unit for forming a second developer image for forming a base on the recording medium;
A calculation unit for determining a second developer amount used for the second developer image based on a first developer amount used for the first developer image;
An image forming apparatus comprising: a printing unit configured to form the first developer image and the second developer image on the recording medium. The image forming apparatus according to claim 8, wherein the calculation unit determines the second developer amount according to a type of the recording medium. The image forming apparatus according to claim 9, wherein the calculation unit determines the second developer amount using a density coefficient set in advance according to a type of the recording medium. The image forming apparatus according to claim 10, wherein the calculating unit determines the second developer amount by using a gray scale value obtained from the first developer image and the density coefficient. apparatus. 12. The image forming apparatus according to claim 9, wherein the type of the recording medium is classified based on a color. The image forming apparatus according to any one of claims 8 to 12, wherein the second developer image has higher brightness than the first developer image. The image forming apparatus according to claim 8, wherein the second developer is white. A first developer image creating step of forming a first developer image for image formation transferred on a recording medium;
A second developer image creating step of forming a second developer image for forming a base on the recording medium;
A calculation step of determining a second developer amount used for the second developer image based on a first developer amount used for the first developer image. .