JP6517635B2 - DATA GENERATION APPARATUS, IMAGE FORMING APPARATUS, AND DATA GENERATION METHOD - Google Patents

Description

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

  The conventional inkjet printer forms a base by applying a white developer on the entire surface of the medium or the base of the entire print image (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-038063

  However, in the prior art, there is a problem that the white developer is wasted because the white developer is uniformly applied even in the case of printing light medium, dark printed image on the medium, etc. .

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

In order to solve the above problems, a data generation apparatus according to the present invention comprises: a first developer preparation unit for forming a first developer image for image formation to be transferred onto a recording medium; A second developer image forming unit for forming a second developer image for forming an undercoat in the second developer image, and the second developer image based on a first developer amount used for the first developer image A calculation unit for determining a second developer amount to be used , the calculation unit being obtained from the first developer image and a density coefficient preset according to the type of the recording medium The second developer amount is determined using a gray scale value, and the second developer concentration value is increased as the gray scale value obtained from the first developer image is increased. Is characterized by becoming smaller .

In the image forming apparatus according to the present invention, a first developer image forming unit for forming a first developer image for image formation to be transferred onto a recording medium, and a base formation on the recording medium A second developer image forming unit for forming a second developer image for the second 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 printing unit for forming the first developer image and the second developer image on the recording medium, the calculating unit further comprising: The second developer amount is determined using a density coefficient set in advance according to the type of the toner and the gray scale value obtained from the first developer image, and the first developer amount is determined. As the value of the gray scale value obtained from the developer image increases, the density value of the second developer decreases. It is characterized in Rukoto.

Further, according to the data generation method of the present invention, there is provided a first developer image forming step of forming a first developer image for image formation to be transferred onto a recording medium, and forming an undercoat on the recording medium A second developer image forming process for forming a second developer image for the second developer, and a second developer image used for the second developer image based on a first developer amount used for the first developer image Calculation step of determining the amount of developer in step 2, and in the calculation step, a density coefficient preset according to the type of the recording medium, and a gray scale value obtained from the first developer image The second developer amount is determined using the following equation, and the density value of the second developer decreases as the value of the gray scale value obtained from the first developer image increases. It is characterized by

  According to the present invention, it is possible to provide a data generating device, an image forming device and a data generating method capable of saving a white developer without impairing the identifiability of a print image.

FIG. 1 is a schematic configuration diagram of a printer 1 as an image forming apparatus according to the present embodiment. FIG. 2 is a block diagram for explaining the functional configuration of a printer 1 and a PC 100 connected to the printer 1; 6 is a flowchart illustrating main processing in the printer 1; It is a flowchart explaining the ground preparation processing in Step S110 of FIG. It is a flowchart explaining the gray scale processing in step S204 of FIG. The coefficients used to calculate the white density value are listed by color paper type. The graph shows the relationship between gray scale values and white density values. When forming the printing image from which a density | concentration differs on black paper, the difference of the white density value applied to a base is illustrated in figure. When forming an image of a predetermined density image on sheets 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.

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

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

  The ID units 4K to 4W are provided to form a developer image, and are configured to be attachable to and detachable from the printer 1. The ID units 4K to 4W include photosensitive drums 7K to 7W as image carriers for forming electrostatic latent images on the surfaces, and charging rollers 8K to 8W that 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 the toners are supplied to the developing rollers 9K to 9W and developing rollers 9K to 9W as a developing unit for forming a toner image, The image forming apparatus includes supply rollers 10K to 10W as a supply unit that performs frictional charging.

  The photosensitive drums 7K to 7W are each composed of a conductive support and a photoconductive layer, and for example, a charge generation layer as a photoconductive layer and a charge transport layer are sequentially laminated on a metal shaft such as aluminum as the conductive support. The organic photoreceptor is configured as described above.

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

  In the developing rollers 9K to 9W, for example, urethane rubber in which carbon black is dispersed is disposed 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 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 6 K to 6 W as exposure units for forming electrostatic latent images on the surfaces of the photosensitive drums 7 K to 7 W are provided immediately above the photosensitive drums 7 K to 7 W. The LED heads 6K to 6W are, for example, LED heads having light emitting elements such as LED elements and a lens array, and irradiation light output from the LED elements based on image data forms an image on the surfaces of the photosensitive drums 7K to 7W. It is arranged to be in position.

  In the present embodiment, although the amount of light irradiation in the LED head 6W is changed to adjust the amount of white toner of the base for changing the electrostatic latent image formed on the surface of the photosensitive drum 7W, The present invention is not limited to this, and the voltage applied to any one 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 drive roller 12, a belt driven roller 13, and a secondary transfer backup roller 14, and is driven by the rotation of the drive 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 movably between the primary transfer rollers 5K to 5W and the ID units 4K to 4W.

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

  The cleaning blade 15 is disposed in contact with a position facing the belt driven roller 13 of the intermediate transfer belt 11 and scrapes residual toner and the like remaining on the intermediate transfer belt 11 without being secondarily transferred. The residual toner and the like scraped off by the cleaning blade 15 are accommodated in the 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 onto the intermediate transfer belt 11 to the recording medium 3 based on a voltage applied from a high voltage power supply (not shown) based on an instruction from a transfer voltage control unit (not shown). Transcribe.

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

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

  The recording medium 3 on which the toner image is fixed is conveyed to the re-conveying path 34 or discharged out of the apparatus by the selection operation of the conveyance separator 33 driven by the driving means. When the recording medium 3 is conveyed to the re-conveying path 34, the recording medium 3 is conveyed by the re-conveying rollers 35-1, 35-2, and 35-3 and joins the conveyance path 32. On the other hand, when discharged out of the apparatus, the recording medium 3 is discharged out of the apparatus by the discharge roller 36. The writing sensor 37 and the discharge sensor 38 are mechanical sensors for detecting the passage of the recording medium 3, and operate each time the recording medium 3 passes. The detection signal output from the writing sensor 37 or the discharge sensor 38 is used, for example, as an image formation start timing or a driving 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 includes an application 101 for the 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 the user. Then, when the user executes a print start operation, the application 101 passes the PC creation data to the printer driver 102 to start printing.

  The printer driver 102 is software for driving the printer 1, and converts PC created data acquired from the application 101 into a format that can be analyzed by the printer 1. Specifically, the printer driver 102 converts PC creation data in the bitmap format generated in the application 101 into PDL data in the script format expressed in PDL (Page Description Language) format. Further, the printer driver 102 adds the sheet color information input from the sheet 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 matter to input paper color information including information on the user who receives the printed matter. For example, as a specific mode of the paper color information input unit 103, for example, a keyboard, a mouse or the like connected to the PC 100 can be mentioned. The paper color information input to the paper color information input unit 103 is the color of the paper serving as the recording medium 3. In the following, one of three types “black, gray, white” can be selected. If not selected, it is assumed that "white" is selected. The sheet color information input to the sheet 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 through 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 components.

  The controller control unit 200 includes a data receiving unit 210, a job control unit 220, a color image forming unit 230 as a first developer image forming unit, a background forming 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 divides the PDL data received by the data receiving unit 210 into job units and analyzes the printer job language. PJL (Printer Job Language) is a representative example of the printer job language.

  The job control unit 220 acquires print color settings 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 for using white (white use setting). Further, when there is a designation command for setting the white density value, the job control unit 220 notifies the white density value storage unit 255 to store the white density value (white density setting). The white use setting or the white density value setting 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, even if it is not acquired as a printer job language. It can also be stored in the unit 254 and the white density value storage unit 255. In addition, the printer 1 may store these setting values in advance. In this case, for example, the job control unit 220 includes a memory 220 a as a setting value storage unit, and stores the white use setting or the white density value setting in the memory 220 a. Accordingly, 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 to be able to change (update) the setting value stored in the memory 220 a when receiving an input from the user via the operator panel unit 400. Further, the job control unit 220 instructs the color image generation unit 230 to convert PDL data of one job into color image data. At the time of this conversion work, PDL data is analyzed in page units, and is converted into a printable data format by a printing unit 330 described later.

  The color image creation unit 230 analyzes the PDL data based on the instruction from the job control unit 220, and creates color image data as a first developer image. The created color image data is composed of 32 bits for each object, and the gradation values of each color to be drawn for each identical object are arranged at adjacent addresses. The color space used in the present embodiment is, for example, a CMYK color space. The color image data of each object has tone values arranged in the order of cyan (C), magenta (M), yellow (Y) and black (K). That is, 8 bits are allocated to each color, and the gradation value of each color is expressed in 256 steps of 0 to 255. Then, the color image generation unit 230 passes 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 creating unit 240 includes a gray scale converting unit 241, a white density value calculating unit 242 as a calculating unit that calculates a white density value of the background based on the gray scale value and the sheet color, and a second developer image creating unit. And color image data stored in the color image storage unit 251 according to an instruction from the job control unit 220, and white image data as a second developer image for background Create

  The grayscale unit 241 is a density conversion unit that converts color image data having color data into grayscale values 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, from the color image data stored in the color image storage unit 251, the gray scale conversion unit 241 sets cyan (C), magenta (M), yellow (Y), and black (K) as color data of each object. Read the tone value of each component of. Then, the gray scale unit 241 calculates a gray scale value from the read gray scale value. Then, the gray scale processing unit 241 passes the calculated gray scale value to the white density value calculation unit 242, and passes the information at which the object is located 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 the coefficient determined by the paper color. The method of 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 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 scaler 241, thereby forming the ground color image data for forming the ground of the color image data. Generate white image data as The white image data is binarized image data. Then, the white image generation unit 243 transfers 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 the setting 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 white use setting as a base color use setting indicating whether to use a base color.

  The white density value storage unit 255 stores white density settings indicating white density values 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 the color image data created by the controller control unit 200. For example, after the process control unit 300 forms an image represented by white image data on the recording medium 3 using a white color material (toner), an image represented by color image data is displayed for each color (cyan (C)). And magenta (M), yellow (Y) and black (K) color materials (toner). The process control unit 300 includes a white image tone conversion unit 310, a color image tone conversion unit 320, and a printing unit 330.

  The white image tone conversion unit 310 performs output tone conversion so that the white image data generated by the controller control unit 200 has an output resolution that the printing unit 330 can handle.

  The color image tone conversion unit 320 performs output tone conversion so that the color image data created by the controller control unit 200 can be output resolution that the printing unit 330 can handle.

  The printing unit 330 prints the white image data output toned by the white image gradation conversion unit 310 and the color image data output toned by the color image gradation 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 print 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 the density adjustment of the white image data in the base portion.

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

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

  The supply voltage control unit 344 adjusts the density of the white image data and the color image data by adjusting the applied voltage from the 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, and the like, and displays device information to the user and receives 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 use setting unit 410 receives an input of setting of use of white as the background color from the user, and stores the received setting in the white use storage unit 254.

  The white density value setting unit 420 receives an input of setting of the white density value as the density value of the background 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 the present embodiment will be described. FIG. 3 is a flowchart illustrating main processing in the printer 1.

  First, in step S101, the data receiving unit 210 receives PDL data, which is print data. 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 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 the presence or absence of use of colored paper (presence or absence of selection of colored paper by the printer driver 102). Then, if color paper is used (Yes at step S102), the process by the job control unit 220 proceeds to step S103. On the other hand, if the blank sheet is used (No at Step S102), the process by the job control unit 220 proceeds to Step S105.

  In step S103, 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. The 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 base formation instruction. The white use storage unit 254 that has received the notification stores the white use setting that uses white (step S104).

  The white use setting can be included in PDL data, which is print data, as setting information for each print job. However, even if there is no command that means them in the printer job language included in the PDL data, as described above, the memory 220a can be held in advance as a device setting, or the user via the operator panel unit 400 Can be set.

  In step S105, the job control unit 220 passes the acquired PDL data to the color image generation unit 230, and starts editing processing. The color image creation unit 230 analyzes the page description language, starts editing processing of graphic information, text information, image information and the like 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 the creation result is image data of 256 gradations expressed by the CMYK color model as a color space. 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 of one pixel is quadrupled, and one pixel is represented by 4 Bite (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 the adjacent address. The gray scale unit 241 calculates a gray scale value from the pixel value of each pixel of the color image data. Also, the background creating unit 240 creates white image data from the gray scale values calculated by the gray scale converting 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 generation unit 230 in the color image storage unit 251 (step S108).

  Next, the job control unit 220 acquires the setting value of the predetermined color stored in the paper color information storage unit 253, and determines whether the white color of the background can be printed. 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. The background creating unit 240 that has received the notification 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 (step S109 No), the process by the job control unit 220 proceeds to step S111.

  In step S111, 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, in the process control unit 300, the color image data acquired by the color image tone conversion unit 141 is subjected to tone conversion to output tone. 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 at Step 109), and when the background creation processing is performed, the printing unit 330 is based on the gradation-converted white image data and the gradation-converted color image data. Printing on the recording medium 3 is performed. On the other hand, when there is no background creation instruction (No at step S109) and the background creation processing is not performed, the printing unit 330 executes printing on the recording medium 3 based on the gradation-converted color image data. .

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

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

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

  In response to the reading instruction in step S103 of FIG. 3, the gray scale conversion unit 241 in the background creating unit 240 obtains coefficients (inclination: A, section: 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 object units from the color image data stored in the storage destination notified from the job control unit 220 in the color image storage unit 251. As described above, pixel values for one pixel are expressed in a 32 Bit pack format. Therefore, in step S202, the gray scale processing unit 241 extracts the gradation values of each color (here, cyan, magenta, yellow, and black) from the pixel information in the 32 bit pack format in 8 bits (step 203).

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

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

  Then, the background creation unit 240 determines whether or not the 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 at step S207), the process 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 at Step S207), in other words, if there are objects for which the 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 processing unit 241 acquires pixel values of objects for which grayscale processing has not been performed yet.

  In step S208, the background generation 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 the white image data to the process control unit 300 to form an image. For example, the process control unit 300 performs gradation conversion of the white image data acquired by the white image gradation conversion unit 310 into an output gradation (step S209). Then, the white image tone conversion unit 310 passes the tone-converted white image data to the printing unit 330. The printing unit 330 starts printing when color image data and white image data are collected in step S111 of FIG.

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

  The gray scale unit 241 averages the cyan, magenta, yellow, and black gradation values of the pixels extracted in step S203 of FIG. 4 in object units, and calculates each of the gradation values as a cyan average gradation value and a magenta average floor. A tone value, a yellow average tone value, and a black average tone value are defined (step S301).

  The gray scaler 241 multiplies the average cyan tone defined in step S301 by the preset gray scale factor value of cyan to calculate the gray scale value of cyan (step S302).

  The gray scale unit 241 multiplies the magenta average tone defined in step S301 by the preset gray scale factor value of magenta to calculate the magenta gray scale value (step S303).

  The gray scaler 241 multiplies the average yellow tone defined in step S301 by the preset gray scale factor value of yellow to calculate the gray scale value of yellow (step S304).

  Next, the gray scale unit 241 determines in step S301 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 like. The gray scale value is calculated by the sum of the calculated black average gradation value. Then, the gray scale processing unit 241 stores the calculated gray scale value and the information indicating the pixel position at which the pixel value used when calculating the gray scale value is acquired in the white density value storage unit 255 (step S305). ). The detailed calculation method of the gray scale value will be described later.

  FIG. 6 is a list of coefficients used to calculate the white density value for each type of color 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. And is stored in advance in the paper color information storage unit 253 according to the type of colored paper. Here, when "white paper" is selected as the paper, "black paper" and "grey paper" are selected as the paper, while the coefficient does not use white as the ground (A = 0, B = 0). If it is done, use white for the background. In the present invention, when printing a predetermined print image on colored paper, the coefficients A and B are both "black paper"> "grey paper" in order to make the background white density value darker as darker color paper It is a good value.

  FIG. 7 is a graph showing the relationship between gray scale values and white density values. As shown in FIG. 7, the white density value Y is represented by a straight line graph with an inclination -A, an intercept B, and a gray scale value (X). Here, the values shown in FIG. 6 are applied to the slope -A and the intercept B. Further, in the present invention, when a predetermined print image is printed on color paper, the lower the density of the print image, the darker the white density value of the background is. 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 dark (X = 255), the background Does not apply white density values to

FIG. 8 graphically illustrates differences in white density values applied to the base when printing images (objects 1 to 3) having different densities are formed on black paper. Here, since the paper serving 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 printing the object 1 on black paper, the white density value of the base of the print image (print image 1) to be formed is calculated as follows.
The gray scale value (X) of the object 1 is referred to the value of FIG. 10 described later.
Gray scale value (X): 8
Background white density value (D): D = −0.392 × 8 + 100 = 96.9 [%]
(2) When printing the object 2 on black paper, the white density value of the base of the print image (print image 2) to be formed is calculated as follows.
The gray scale value (X) of the object 2 is referred to the value of FIG. 11 described later.
Gray scale value (X): 26
Background white density value (D): D = -0.392 × 26 + 100 = 89.8 [%]
(3) When printing the object 3 on black paper, the white density value of the base of the print image (print image 3) to be formed is calculated as follows.
The gray scale value (X) of the object 3 is referred to the value of FIG. 12 described later.
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 paper (black paper, gray paper, white paper) of different colors.
(4) When printing the object 1 on gray paper, the white density value of the base of the print image (print image 4) to be formed is calculated as follows.
Since the paper serving as the recording medium 3 is gray paper, the coefficients shown in FIG. 6 are read out from the paper color information storage unit 253 as the coefficients (A, B) for calculating the white density value.
A [% / level] = B / 255 = 0.196 [% / level], B [%] = 50 [%]
The gray scale value (X) of the object 1 is referred to the value of FIG. 10 described later.
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 base of the print image (print image 5) to be formed is calculated as follows.
Since the sheet serving as the recording medium 3 is blank, the coefficients shown in FIG. 6 are read from the sheet color information storage unit 253 as the coefficients (A, B) for calculating the white density value.
The gray scale value (X) of the object 1 is referred to the value of FIG. 10 described later.
Gray scale value (X): 8
Background white density value (D): D = 0 × 8 + 0 = 0 [%]

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

The color images (objects 1 to 3) use the color images of different density shown in FIG.
The following equation is used to calculate the gray scale value.
GV = CV x CC + MV x MC + YV x YC + KV
However, GV is a gray scale value. CV is a tone value of cyan, and CC is a gray scale factor value of cyan, which is “0.2988” here. MV is a tone value of magenta, and MC is a gray scale factor value of magenta, which is "0.5868" here. YV is a tone value of yellow, and YC is a gray scale factor value of yellow, which is “0.1144” here. KV is a gradation value of black.
The cyan, magenta and yellow grayscale factor values are values used in the NTSC weighted average method. Note that these gray scale factor values are weighting factor values, and may be changed in consideration of the toner characteristics of each color. In the present embodiment, the gray scale value is calculated by the above equation. However, the gray scale value may be calculated by another method. In this case, for example, the gray scale value can be calculated by a simple averaging method, a median method, or a weighted averaging and correction method using HDTV coefficients.

In addition, the calculation example of the gray scale value of the objects 1-3 to which the said Formula is applied is as follows.
Object 1
GV = 0.2988 x 0.1 x 255 8 8
Object 2
GV = 0.2988 x 1 x 255 + 0.5868 x 1 x 255 226 226
Object 3
GV = 0.2988 x 0.1 x 255 + 0.5868 x 0.1 x 255 + 0.1144 x 0.1 x 255 26 26

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

  Although the case of using the color of the recording medium as a reference has been described in the description of the present embodiment, the present invention is not limited to the color of the recording medium. The amount of developer may be changed. Also, the amount of each developer may be changed according to the information of the recording medium acquired via a scanner or the like.

  In addition, although the white density value control of the background according to the present embodiment is performed in object units obtained by averaging a plurality of pixels due to restrictions on processing speed and LED head exposure control, control may be performed in pixel units.

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 charge roller 9K-9W development roller 10K-10W supply roller 11 intermediate transfer belt 12 drive roller 13 belt driven roller 14 secondary transfer backup roller 15 cleaning blade 16 cleaner container 18 cleaner roller 18 registration roller 19 transfer roller 21 secondary transfer roller 32 transfer path 33 transfer separator 34 re-transfer path 35-1, 35-2, 35- 3 re-conveying roller 36 discharging roller 37 writing sensor 38 discharging sensor 50 fixing device 51 heat roller 52 pressure roller 100 PC
101 application 102 printer driver 103 paper color information input unit 104 data transmission unit 200 controller control unit 210 data reception unit 220 job control unit 230 color image creation unit 240 background creation unit 241 gray scale unit 242 white density value calculation unit 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 tone conversion unit 320 color image tone conversion unit 330 printing unit 340 printing density control unit 341 exposure control unit 342 charging voltage control unit 343 developing 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 preparation unit for forming a first developer image for image formation to be reproduced on a recording medium;
A second developer image forming unit for forming a second developer image for base formation on the recording medium;
A calculation unit that determines a second developer amount used for the second developer image based on the first developer amount used for the first developer image ;
The calculation unit determines the second developer amount using a density coefficient set in advance according to the type of the recording medium and a gray scale value obtained from the first developer image. And
The data generating device according to claim 1, wherein the density value of the second developer decreases as the value of the gray scale value obtained from the first developer image increases . When the density value Y of the second developer has an inclination of the density coefficient of −A, an intercept of B, and the gray scale value of X,
Formula: Y = -A x X + B
Calculated from
The data generation device according to claim 1, characterized in that The gray scale value is calculated from the sum of the gray scale value of cyan, the gray scale value of magenta, the gray scale value of yellow, and the average gray scale value of black constituting the first developer image. about
The data generation apparatus according to claim 1 or 2, wherein The cyan gray scale value, the magenta gray scale value, or the yellow gray scale value may be calculated by multiplying the average gray scale value of each color by a predetermined gray scale factor.
The data generation apparatus according to claim 3, characterized in that The type of the recording medium is data generating apparatus according to any one of claims 1 to 4, characterized in that those classified based on the color. The data generating apparatus according to any one of claims 1 to 5, wherein the second developer image has a higher brightness than the first developer image. The data generation device according to any one of claims 1 to 6, wherein the second developer is white. A first developer image forming unit for forming a first developer image for image formation to be transferred onto a recording medium;
A second developer image forming unit for forming a second developer image for base formation on the recording medium;
A calculation unit that determines a second developer amount used for the second developer image based on the first developer amount used for the first developer image;
A printing unit that forms the first developer image and the second developer image on the recording medium;
The calculation unit determines the second developer amount using a density coefficient set in advance according to the type of the recording medium and a gray scale value obtained from the first developer image. And
2. An image forming apparatus according to claim 1, wherein the density value of the second developer decreases as the gray scale value obtained from the first developer image increases . When the density value Y of the second developer has an inclination of the density coefficient of −A, an intercept of B, and the gray scale value of X,
Formula: Y = -A x X + B
Calculated from
The image forming apparatus according to claim 8, characterized in that The gray scale value is calculated from the sum of the gray scale value of cyan, the gray scale value of magenta, the gray scale value of yellow, and the average gray scale value of black constituting the first developer image. about
The image forming apparatus according to claim 8 or 9, wherein The cyan gray scale value, the magenta gray scale value, or the yellow gray scale value may be calculated by multiplying the average gray scale value of each color by a predetermined gray scale factor.
The image forming apparatus according to claim 10, characterized in that The image forming apparatus according to any one of claims 8 to 11, 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 a higher brightness than the first developer image. The image forming apparatus according to any one of claims 8 to 13, wherein the second developer is white. A first developer image forming step of forming a first developer image for image formation to be transferred onto a recording medium;
A second developer image forming step of forming a second developer image for base formation on the recording medium;
Calculating a second developer amount to be used for the second developer image based on the first developer amount to be used for the first developer image;
In the calculation step, the second developer amount is determined using a density coefficient set in advance according to the type of the recording medium and a gray scale value obtained from the first developer image. And
2. A data generating method according to claim 1, wherein the density value of the second developer decreases as the value of the gray scale value obtained from the first developer image increases .