JP2011055395A - Printing using multiple color inks including white ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate approximating a color of a white image to a target color when performing printing color images and the white image. <P>SOLUTION: A printing device includes: a head having a first nozzle group which jets inks for forming color images and a second nozzle group which jets a white ink and at least one color ink other than the white ink for forming a color-toning white image; a control unit which controls the head to form the color images and the color-toning white image on a printing medium; a designation information acquisition unit for acquiring a designation of one of a plurality of specific white inks as a target of a color for the color-toning white image; an image data acquisition unit for acquiring white image data indicating a gray scale value of the white image; and a memory for storing information, preset for the plurality of specific white inks, indicating a correspondence relationship between the gray scale value of the white image and a gray scale value for each ink color. The control unit converts the white image data into gray scale value data for each ink color based on the correspondence relationship information of the designated specific white ink and uses the gray scale value data for each ink color to form the color-toning white image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for performing printing using a plurality of colors of ink including white ink.

  In addition to color inks such as cyan, magenta, and yellow, printing apparatuses that perform printing using white (white) ink are known (see, for example, Patent Document 1). Printing apparatus that performs printing using a plurality of color inks including a white ink, for example, in order to reproduce a color image without being influenced by the ground color of the print medium, the underlying process and the land of the print medium using the white ink It is possible to perform complementary color processing according to the color.

JP 2007-282205 A

  In general, the color of white ink (white ink) used in a printer such as gravure printing or flexographic printing and the color of white ink used in a printer such as an ink jet printer, even for the same ink called “white ink” May be different from each other. Further, even for white ink used in a printing press, the color may differ depending on the manufacturer or the type of printing press. Therefore, for example, it has not been easy to reproduce a white image formed by a specific white ink used in a gravure printing machine using an inkjet printer.

  Such a problem is not limited to the case of using an ink jet printer, but is a common problem when a color image and a white image are printed using a plurality of colors of ink including white ink.

  The present invention has been made to solve the above-described problems, and when printing a color image and a white image using a plurality of colors of ink including white, the color of the white image can be easily set to the target color. It aims to make it possible to approximate.

  In order to solve at least a part of the above problems, the present invention can be realized as the following forms or application examples.

A printing apparatus for performing printing using a plurality of color inks including Application Example 1] White,
A first nozzle group that ejects ink to form a color image on the print medium; and at least one other than white and white to form a toned white image that is an adjusted white color on the print medium A head having a second nozzle group for ejecting ink of color;
A control unit that controls the head to form the color image and the toned white image on the print medium;
A designation information acquisition unit for acquiring designation information for designating one of a plurality of specific white inks as a color target of the toned white image;
An image data acquisition unit for acquiring white image data indicating a gradation value of the white image;
A storage unit configured to store correspondence information indicating a correspondence relationship between a gradation value of the white image and a gradation value for each ink color used in the printing apparatus, which is set in advance for each of the plurality of specific white inks; With
The control unit converts the white image data into data representing a gradation value for each ink color based on the correspondence information for the specific white ink designated by the designation information, and converts the level for each ink color. A printing apparatus that forms the toned white image using data representing a tone value.

  In this printing apparatus, correspondence information indicating the correspondence between the gradation value of the white image and the gradation value for each ink color used in the printing apparatus is preset and stored, and the color of the toned white image The white image data indicating the gradation value of the white image is converted into data representing the gradation value for each ink color based on the correspondence information for one specific white ink designated as the target of the ink, and the level for each ink color is converted. Since the toned white image is formed using the data representing the tone value, the color of the white image can be easily approximated to the target color.

[Application Example 2] The printing apparatus according to Application Example 1,
The correspondence information is set so that the entire range of gradation values of the white image is associated with a partial range that does not include the maximum gradation value of the white ink with respect to at least one specific white ink. A printing device.

  In this printing apparatus, the color of the white image can be approximated to the target color by flexibly setting the gradation value of the white ink according to the type of the specific white ink.

[Application Example 3] The printing apparatus according to Application Example 1 or Application Example 2,
The printing device, wherein the plurality of specific white inks are inks that are not used in the printing device.

  In this printing apparatus, the color of the white image can be easily approximated to the color of the specific white ink that is not used in the printing apparatus as the target color.

[Application Example 4] The printing apparatus according to Application Example 3,
The specified information acquisition unit acquires information specifying at least one of a manufacturer of the specific white ink and a manufacturer of a printing machine in which the specific white ink is used as the specified information.

  In this printing apparatus, the specific white ink as the target color can be easily specified.

Application Example 5 In the printing apparatus according to any one of Application Examples 1 to 4,
The designation information includes printing order designation showing the print order of the color image and the toned-white image,
The printing apparatus, wherein the correspondence information indicates the correspondence set for each combination of the specific white ink and the printing order.

  In this printing apparatus, in accordance with the combination of the print order and the type of the specific white ink, by setting the gray scale value of the white ink flexible, it can be approximated by the target color the color of the white image.

Application Example 6 In the printing apparatus according to any one of Application Examples 1 to 5,
The control unit is configured to form the color image using the first nozzle group and form the toned white image using the second nozzle group in at least a part of the printing period. A printing apparatus that controls the head so that the two are performed in parallel.

  In this printing apparatus, when a color image and a white image are printed in parallel using a plurality of colors including white, the color of the white image can be easily approximated to the target color.

Application Example 7 In the printing apparatus according to any one of Application Examples 1 to 6,
The multi-color ink includes a combination of a light color ink and a dark color ink for at least one hue;
The printing apparatus in which the second nozzle group does not eject the dark ink.

  In this printing apparatus, it is possible to suppress deterioration in image quality (increase in graininess) in a toned white image while approximating the color of the white image to the target color.

  The present invention can be realized in various modes. For example, a printing method and apparatus, a printing control method and apparatus, a printing system, and a computer program for realizing the functions of these method, apparatus, and system It can be realized in the form of a recording medium recording the computer program, a data signal including the computer program and embodied in a carrier wave, and the like.

It is explanatory drawing which shows schematically the structure of the printing system in the Example of this invention. It is explanatory drawing which shows the structure of PC200 roughly. FIG. 2 is an explanatory diagram schematically illustrating a configuration of a printer. 2 is a block diagram functionally showing the configuration of a PC 200. FIG. FIG. 2 is a block diagram functionally showing the configuration of a printer. 3 is a flowchart showing a flow of printing processing in the printing system 10 of the present embodiment. It is explanatory drawing which shows an example of the printing image PI color image data Cdata and white image data WIdata. It is explanatory drawing which shows the printing order of a color image and a toning white image. 4 is a flowchart illustrating a flow of processing by a CPU 210 that executes a printer driver 300. It is explanatory drawing which shows an example of the window W1 for simulation ink selection. It is a flowchart which shows the flow of the ink color data generation process for white images. It is explanatory drawing which shows an example of the content of the ink information table IIT. It is explanatory drawing which shows notionally the outline | summary of the production | generation of ink color data, and a halftone process. It is a flowchart which shows the flow of the ink color separation process for color images. It is explanatory drawing which shows partially an example of the look-up table for color images LUTc. It is a flowchart which shows the flow of a halftone process. It is a flowchart which shows the flow of command creation processing. It is explanatory drawing which shows an example of the command produced by command creation processing. It is explanatory drawing which shows an example of the content of the ink code table | surface ICT. 3 is a flowchart showing a flow of processing by the printer. It is explanatory drawing which shows the detailed structure of a raster buffer and a head buffer. 4 is an explanatory diagram illustrating a configuration of a print head 144 of the printer 100. FIG.

Next, embodiments of the present invention will be described in the following order based on examples.
A. Example:
A-1. Printing system configuration:
A-2. Printing process:
B. Variation:

A. Example:
A-1. Configuration of printing system:
Figure 1 is an explanatory view schematically showing a configuration of a printing system in an embodiment of the present invention. The printing system 10 according to the present exemplary embodiment includes a printer 100 and a personal computer (PC) 200. The printer 100 is an ink jet color printer that prints an image by ejecting ink to form ink dots on a printing medium (for example, printing paper or transparent film). The PC 200 functions as a print control apparatus that supplies printing data to the printer 100 and controls the printing operation by the printer 100. The printer 100 and the PC 200, and is information communicably connected by wire or wireless. Specifically, in this embodiment, the printer 100 and the PC 200 are connected to each other by a USB cable.

  The printer 100 of this embodiment includes cyan (C), magenta (M), yellow (Y), black (K), light cyan (Lc), light magenta (Lm), and white (W). The printer performs printing using a total of seven colors of ink. The printing system 10 according to the present embodiment realizes a printing process in which a color image and a toned white image are formed in parallel on a transparent film as a printing medium. The transparent film on which the color image and the toned white image are formed is used, for example, as a color proof or product sample (mockup) of a product packaging film printed by a gravure printing machine.

  In the present specification, adjusting white by mixing white ink with another color ink is referred to as “white toning”. Further, white (adjusted white) generated by white toning is called “toned white”, and an image composed of toned white is called “toned white image”.

  FIG. 2 is an explanatory diagram schematically showing the configuration of the PC 200. The PC 200 includes a CPU 210, a ROM 220, a RAM 230, a USB interface (USB I / F) 240, a network interface (N / W I / F) 250, a display interface (display I / F) 260, and a serial interface ( Serial I / F) 270, hard disk drive (HDD) 280, and CD drive 290 are included. Each component of the PC 200 is connected to each other via a bus.

  A USB cable for connection with the printer 100 is connected to the USB interface 240 of the PC 200. A monitor MON as a display device is connected to the display interface 260. The serial interface 270 is connected to a keyboard KB and a mouse MOU as input devices. Note that the configuration of the PC 200 illustrated in FIG. 2 is merely an example, and some of the components of the PC 200 may be omitted or further components may be added to the PC 200.

  FIG. 3 is an explanatory diagram schematically showing the configuration of the printer 100. The printer 100 includes a CPU 110, a ROM 120, a RAM 130, a head controller 140, a print head 144, a carriage controller (CR controller) 150, a carriage motor (CR motor) 152, and a print medium feed controller (PF controller) 160. A print medium feed motor (PF motor) 162, a USB interface (USB I / F) 170, and a network interface (N / W I / F) 180. Each component of the printer 100 is connected to each other via a bus.

  The CPU 110 of the printer 100 functions as a control unit that controls the operation of the entire printer 100 by executing a computer program stored in the ROM 120. The print head 144 of the printer 100 is mounted on a carriage (not shown). The carriage controller 150 controls the carriage motor 152 to reciprocate the carriage in a predetermined direction. Thereby, the main scanning in which the print head 144 reciprocates along a predetermined direction (main scanning direction) of the print medium is realized. The print medium feed controller 160 controls the print medium feed motor 162 to perform sub-scanning for transporting the print medium in a direction (sub-scanning direction) orthogonal to the main scanning direction. The print head 144 has a nozzle group (see FIG. 22) that ejects ink, and the head controller 140 controls ink ejection from the nozzle group by the print head 144 in conjunction with main scanning and sub scanning. Thereby, formation of an image (printing of an image) on the print medium is realized.

  FIG. 4 is a block diagram functionally showing the configuration of the PC 200. The hard disk drive 280 (FIG. 2) of the PC 200 stores an application program AP and a printer driver 300 as computer programs executed by the CPU 210. The application program AP is a program for setting, generating, editing, and the like of an image (hereinafter also referred to as “print image PI”) to be printed on a transparent film as a print medium. The CPU 210 executes setting of the print image PI, generation, and editing by executing the application program AP.

  In addition, the CPU 210 that executes the application program AP outputs color image data Cdata, white image data WIdata, and print order designation information SS to the printer driver 300 in accordance with a print execution instruction from the user. The contents of each data will be described in detail in “A-2. Printing process”.

  The printer driver 300 (FIG. 4) is a program for controlling the printer 100 (FIG. 1) to print the print image PI. The CPU 210 (FIG. 2) implements print control of the print image PI by the printer 100 by executing the printer driver 300.

  As shown in FIG. 4, the printer driver 300 includes an ink color image color separation processing module 310, a halftone processing module 320, a simulation ink selected ink color data generation module 330, a command producing module 370, the Contains. The simulation ink selection / ink color data generation module 330 includes a UI control module 332. The HDD 280 (FIG. 2) of the PC 200 stores an ink information table IIT, a color image lookup table (LUT) LUTc, a halftone (HT) resource HT, and an ink code table ICT. The printer driver 300 and each module execute processing with reference to these pieces of information. The function of each module and the contents of each information will be described in detail in “A-2. Printing process”.

  FIG. 5 is a block diagram functionally showing the configuration of the printer 100. A command processing module 112 is stored in the ROM 120 (FIG. 3) of the printer 100 as a computer program executed by the CPU 110. As will be described later, the CPU 110 executes a command processing module 112 to realize processing of a command received from the PC 200. In addition, the RAM 130 (FIG. 3) of the printer 100 has a raster buffer 132. The raster buffer 132 includes two areas of a color image raster buffer 132c and a toned white image raster buffer 132w. The head controller 140 (FIG. 3) of the printer 100 has a head buffer 142. The head buffer 142 includes an upstream head buffer 142u and a downstream head buffer 142l. The functions and detailed configurations of these programs and buffers will be described in detail in “A-2. Printing Process”.

A-2. Printing process:
FIG. 6 is a flowchart showing the flow of printing processing in the printing system 10 of the present embodiment. The printing process of the present embodiment is a process of forming a color image and a toned white image in parallel on a transparent film as a printing medium, and creating a printed matter in which the color image and the toned white image are formed. is there.

  In addition, the printing process of a present Example is performed for preparation of the color proof of the film for product packaging printed with a gravure printing machine or a flexographic printing machine, and a product sample, for example. White ink (white ink) used in the gravure printing machine or flexographic printing machine is different from the white ink used in the printer 100. For this reason, in the printing process of this embodiment, the toning of the white image is executed so that the color of the formed white image approximates the color of a specific white ink used in the printing machine as the target color. Hereinafter, the white ink as the target of the color of the toned white image is also referred to as “simulation ink”.

  In step S110 (FIG. 6), the CPU 210 (FIG. 2) that executes the application program AP (FIG. 4) receives a print execution instruction from the user. In response to receiving the print execution instruction, the CPU 210 outputs the color image data Cdata, the white image data WIdata, and the print order designation information SS to the printer driver 300 (FIG. 4). The color image data Cdata is data for specifying a color image in the print image PI, the white image data WIdata is data for specifying a white image in the print image PI, and the print order designation information SS is a color image and toning. This is data for specifying the printing order (described later) of the color image and the toned white image in the portion where the white image overlaps.

  FIG. 7 is an explanatory diagram illustrating an example of the print image PI, color image data Cdata, and white image data WIdata. FIG. 7A shows an example of the print image PI. The print image PI includes a color image Ic (an image “ABC” in the figure). The print image PI includes a white area Aw and a non-white area An. The white area Aw is an area where a toned white image is formed, and the non-white area An is an area where no toned white image is formed. In this example, an example of characters is described as the color image Ic, but the color image Ic may be an image such as a photograph or an illustration.

  FIG. 7B conceptually shows the color image data Cdata. In this embodiment, the color image data Cdata includes the 8-bit C value, M value, and Y value of the color (gradation value) of each pixel of the print image PI when attention is paid only to the color image Ic of the print image PI. , Data specified by the K value. The color image data Cdata is data specifying the color of the color image Ic for pixels corresponding to the color image Ic of the print image PI, and data indicating that no color image is formed for the remaining pixels (for example, C , M, Y, K = 0).

  FIG. 7C conceptually shows the white image data WIdata. In the present embodiment, the white image data WIdata is data that specifies the color (gradation value) of each pixel of the print image PI with an 8-bit W value when the color image Ic is excluded from the print image PI. White image data WIdata, for the pixels corresponding to the white area Aw of the print image PI, adjustment becomes data indicating the gradation values of the white image, for the remaining pixels (pixels corresponding to the non-white area An), tone Data indicating that a fair image is not formed (for example, W = 0).

  FIG. 8 is an explanatory diagram showing the printing order of a color image and a toned white image. FIG. 8A shows a printing order in which the toned white image Iw is formed on the transparent film as the print medium PM and the color image Ic is formed on the toned white image Iw. In this specification, this printing order is referred to as “white-color printing” or “WC printing”. In the WC printing shown in FIG. 8A, the observer observes the printed matter from the side on which the image of the print medium PM is formed (that is, the front side, the upper side of the figure) (see the arrow in the figure). ). Therefore, “white-color printing” is also called “front printing”.

  FIG. 8B shows a printing order in which the color image Ic is formed on the transparent film as the print medium PM, and the toned white image Iw is formed on the color image Ic. In this specification, this printing order is referred to as “color-white printing” or “C-W printing”. C-W in the print shown in FIG. 8 (b), the viewer becomes possible to observe the printed matter from the image is not formed side of the print medium PM (i.e. the back side, the lower figure) (see an arrow in the drawing) . Therefore, “color-white printing” is also referred to as “back printing”.

  The user selects whether to perform W-C printing or C-W printing according to the usage of the printed matter. The CPU 210 that executes the application program AP generates printing order designation information SS that specifies the printing order selected by the user, and outputs it to the printer driver 300 (FIG. 4).

  In step S120 of the printing process (FIG. 6), processing by the CPU 210 that executes the printer driver 300 (FIG. 4) is executed. FIG. 9 is a flowchart showing the flow of processing by the CPU 210 that executes the printer driver 300. In step S210, the CPU 210 receives the color image data Cdata, white image data WIdata, and printing order designation information SS output from the application program AP (see FIG. 4).

  In step S212 (FIG. 9), the simulation ink selection / ink color data generation module 330 (FIG. 4) executes a simulation ink selection process. The simulation ink selection process is a process of selecting the simulation ink as the color target of the toned white image Iw described above.

  In the simulation ink selection process, the UI control module 332 (FIG. 4) of the simulation ink selection / ink color data generation module 330 displays a window W1 for selecting simulation ink on the monitor MON. FIG. 10 is an explanatory diagram showing an example of a window W1 for selecting simulation ink. As shown in FIG. 10, the window W1, includes a simulated ink selection field for displaying a simulation ink options (e.g., "Company A white ink"), the user, the one ink from the options select. As a result, the simulation ink selection / ink color data generation module 330 receives designation information for designating simulation ink. The simulation ink is ink that is used by a gravure printing machine or the like, and is ink that is not used by the printer 100. In this embodiment, the simulation ink is specified by the manufacturer name of the simulation ink or the manufacturer name of the printing machine in which the simulation ink is used. The simulation ink selection / ink color data generation module 330 corresponds to the designation information acquisition unit in the present invention, and the choice of simulation ink corresponds to the specific white ink in the present invention.

  Note that the window W1 shown in FIG. 10 also includes a printing order (W-C printing or C-W printing) selection field. In the present embodiment, as described above, the printing order designation information SS for designating the printing order is transmitted from the application program AP to the printer driver 300 (see FIG. 4). The print order selection column of the window W1 is displayed in a state where the print order designated by the print order designation information SS is selected. The user can also reselect the printing order in the printing order selection field of the window W1.

  In step S220 in the process by the printer driver 300 (FIG. 9), the printer driver 300 executes a white image ink color data generation process. Ink color data generation processing for a white image is processing for generating data (hereinafter also referred to as “ink color data”) representing the gradation value (density value) of each ink color for forming the toned white image Iw. It is. FIG. 11 is a flowchart showing a flow of ink color data generation processing for a white image. In step S310, the simulation ink selection / ink color data generation module 330 refers to the ink information table IIT (FIG. 4), and the input / output characteristics of the simulation ink designated in the simulation ink selection process (step S212 in FIG. 9). The information indicating is taken out.

  FIG. 12 is an explanatory diagram showing an example of the contents of the ink information table IIT. As shown in FIG. 12, the ink information table IIT includes a combination of a simulation ink type (for example, “A company white ink” or “B company white ink”) and a printing order (CW printing or WC printing). As the information indicating the input / output characteristics, a table indicating the gradation value of each ink color for approximating the color of the toned white image Iw with the color of the simulation ink is included. Specifically, the ink information table IIT is a table showing the correspondence between the gradation value and the gradation value of each ink color of the white image data WIdata for each combination of types of simulation ink and printing order, And a table indicating a pointer indicating the position of each of the plurality of tables. The simulation ink selection / ink color data generation module 330 refers to the pointer and extracts a table regarding the combination of the designated simulation ink type and the printing order as information indicating the input / output characteristics. In FIG. 12, the simulation ink color is shown on the a * b * plane in the CIE-LAB L * a * b * space beside each simulation ink table. As shown in FIG. 12, for example, the color of “Company A white ink” is reddish white made by yellow (Y) and light magenta (Lm), and the color of “B company white ink” is Bluish white made by light cyan (Lc) and light magenta (Lm).

  In this embodiment, as shown in FIG. 12, in this embodiment, a white tone (mixing white ink with another color ink to adjust the white color) and yellow (Y) of six colors of ink other than white are used. , Light cyan (Lc) and light magenta (Lm) are used, and cyan (C) and magenta (M) inks are not used. That is, for the white tone, dark ink is not used among the two types of inks of light color ink and dark color ink for the same hue. Therefore, in the printing process according to the present exemplary embodiment, it is possible to suppress deterioration in image quality (increase in graininess) in the toned white image while setting the color of the toned white image to a desired color. For white toning, black (K) ink may be used. In this way, the brightness of the toned white image can be adjusted, and the selectable range of colors of the toned white image can be expanded.

  Also, as shown in FIG. 12, in the ink information table IIT, the gradation value of the white image as the input value is a value in the range of 0 to 255, whereas the scale of each ink color as the output value. The tone value is in the range of 0 to 4080. For example, in the “WC printing” table of “Company A white ink”, the gradation value of white (W) ink corresponding to the maximum gradation value (255) of the white image is the maximum value (4080). It has become. In this table, light magenta (Lm) and yellow (Y) inks are used for white tones, and light magenta and yellow ink gradation values corresponding to the highest gradation value (255) of the white image. Is much smaller than the maximum value (4080). FIG. 13 is an explanatory diagram conceptually showing an outline of generation of ink color data and halftone processing. FIG. 13 shows an example of a graph (input / output curve) of the correspondence relationship between the gradation value of the white image and the ink gradation value (ink color data) for a certain ink color. As shown in FIGS. 12 and 13, when forming the toned white image Iw, only the low gradation value range is used for inks other than the white ink. In this embodiment, since you are wider range than the range of the gradation values of the ink color (0-4080) of the gradation values of the white image (0 to 255), a relatively even in intermediate gray white image An accurate input / output curve can be set, and the formation of the toned white image Iw closer to the desired color can be realized.

  Also, as shown in FIG. 12, the correspondence between each gradation value of the white image and each ink color gradation value is set independently for each combination of simulation ink and printing order. For example, in the “WC printing” table for “A company white ink” and the “WC printing” table for “B company white ink”, the distribution of gradation values of white (W) ink is mutually Is different. In the “WC printing” table of “Company B white ink”, the gradation value of the white (W) ink corresponding to the maximum gradation value (255) of the white image is higher than the maximum value (4080). It is a small value. That is, in this table, the entire range of gradation values of the white image is associated with a partial range that does not include the maximum gradation value of white (W) ink. As described above, the tone value of each ink color is flexibly set according to the type of the simulation ink and the printing order, whereby the toned white image Iw closer to the desired color can be formed.

  After taking out the information indicating the input / output characteristics of the simulation ink (step S310 in FIG. 11), the simulation ink selection / ink color data generation module 330 takes out the data of one pixel in the white image data (step S320). In step S330, the simulation ink selection / ink color data generation module 330 sets each pixel data (tone value) taken out based on the input / output characteristics (FIG. 12) of the simulation ink shown in the ink information table IIT. Conversion into ink color data representing the gradation value of the ink color. The processing from step S320 to S330 in FIG. 11 is repeatedly executed until the processing for all the pixels of the white image data is completed (see step S350). When the processing for all the pixels is completed (step S350: Yes), the white image ink color data generation processing ends.

  In step S230 in the processing by the printer driver 300 (FIG. 9), the printer driver 300 executes ink color separation processing for a color image. FIG. 14 is a flowchart showing the flow of ink color separation processing for a color image. In step S410, the color image ink color separation processing module 310 (FIG. 4) extracts one pixel data in the color image data. In step S420, the color image ink color separation processing module 310 performs ink color separation processing for converting the extracted one-pixel data (CMYK value) into gradation values (ink color data) for each ink color. As described above, the printer 100 according to this embodiment includes cyan (C), magenta (M), yellow (Y), black (K), light cyan (Lc), and light magenta (Lm). Printing is performed using white (W) and a total of seven colors of ink. Therefore, in the ink color separation process, the CMYK values are converted into the gradation values of the seven ink colors. The ink color separation process is executed with reference to the color image lookup table LUTc (FIG. 4).

  FIG. 15 is an explanatory diagram partially showing an example of the color image lookup table LUTc. As shown in FIG. 15, the color image look-up table LUTc defines a correspondence relationship between preset CMYK values and respective tone values of ink colors. In the color image lookup table LUTc, the CMYK gradation values are defined as values in the range of 0 to 100, and the ink color gradation values are defined as values in the range of 0 to 4080. Has been. The color image ink color separation processing module 310 refers to the color image look-up table LUTc and converts the CMYK values into gradation values for each ink color. As shown in FIG. 15, in this embodiment, six color inks except white are used for forming a color image, and no white ink is used.

  The processes in steps S410 and S420 in FIG. 14 are repeatedly executed until the processes for all the pixels of the color image data are completed (see step S430). When the process for all the pixels is completed (step S430: Yes), the ink color separation process for the color image is completed.

  In step S240 in the processing by the printer driver 300 (FIG. 9), the printer driver 300 executes halftone processing. FIG. 16 is a flowchart showing the flow of halftone processing. Halftone processing is executed by the halftone processing module 320 for each of a white image and a color image. First, pixel data of image data is extracted (step S510), and binarization processing is performed with reference to a dither pattern for each ink color (step S520). The binarization process is executed with reference to a preset halftone resource HT (FIG. 4). The binarization process is repeatedly executed until the process for all ink colors is completed (see step S530). Further, the processing from step S510 to S530 is repeatedly executed until the processing for all the pixels is completed (see step S540).

  With the halftone process shown in FIG. 16, for each of the color image Ic and the toned white image Iw, dot data defining ON / OFF of each ink color dot of each pixel when the image is formed is generated. .

  In step S250 in the processing by the printer driver 300 (FIG. 9), the command creation module 370 (FIG. 4) of the printer driver 300 performs command creation processing. FIG. 17 is a flowchart showing the flow of command creation processing.

  In step S610 of the command creation process (FIG. 17), the command creation module 370 (FIG. 4) creates a print order designation command based on the print order designation information SS output from the application program AP. FIG. 18 is an explanatory diagram showing an example of a command created by command creation processing. FIG. 18A shows an example of the print order designation command. As shown in FIG. 18A, the print order designation command includes an identifier indicating the head of the command, an identifier indicating the print order designation command, a command length (2 bytes), and a print order designation. It is out. In the printing order designation, for example, the value “0” represents C-W printing (the printing order in which the color image Ic is first formed and the toned white image Iw is formed on the color image Ic), and the value “1”. "Represents WC printing (printing order in which the toned white image Iw is first formed and the color image Ic is formed on the toned white image Iw). The command creation module 370 identifies the print order with reference to the print order designation information SS, and creates a print order designation command that designates the identified print order.

  In step S620 (FIG. 17), the command creation module 370 (FIG. 4) creates a vertical position designation command based on the color image dot data and the toned white image dot data received from the halftone processing module 320. . The vertical position designation command is a command for designating the start position of the image along the vertical direction (Y direction). The vertical position designation command is created as a command common to all inks.

  Next, the command creation module 370 (FIG. 4) creates a raster command corresponding to the color image through the processing from step S630 (FIG. 17) to S670. In step S630, the command creation module 370 creates a horizontal position designation command for the selected one ink color based on the color image dot data. The horizontal position designation command is a command for designating the start position of an image along the horizontal direction (X direction) for one ink color when forming a color image. The command creation module 370 refers to color image dot data for one ink color, sets an appropriate image start position, and creates a horizontal position designation command.

  In step S640 (FIG. 17), the command creation module 370 (FIG. 4) extracts one raster worth of dot data for one selected ink color from the color image dot data. In step S650, the command creation module 370 searches the ink code with reference to the ink code table ICT. FIG. 19 is an explanatory diagram showing an example of the contents of the ink code table ICT. As shown in FIG. 19, in this embodiment, a unique ink abbreviation and ink code are assigned to each ink color. Further, in this embodiment, two different ink abbreviations and ink codes for color image and toned white image are assigned to one ink color. That is, the ink abbreviation and the ink code uniquely correspond to the combination of each of the plurality of ink colors and each of the color image and the toned white image. For example, for cyan, assigned ink abbreviation "C" and an ink code "01H" is, the ink abbreviation "WC" for the toned-white image and the ink code "81H" is allocated as a color image. Similarly, for white ink abbreviation and "IW" and ink code "40H" is assigned, the abbreviated ink name "W" for the toned-white image and the ink code "C0H" is allocated as a color image . In this step (S650), the command creation module 370 searches for an ink code for a color image in the ink code table ICT.

  In step S660 (FIG. 17), the command creation module 370 (FIG. 4) creates a raster command based on the extracted dot data for one raster and the retrieved ink code. FIG. 18B shows an example of a raster command. As shown in FIG. 18B, the raster command includes an identifier indicating the head of the command, an identifier indicating the raster command, an ink code, an identifier indicating the presence / absence of data compression, and the number of bits per pixel. X direction length (2 bytes), Y direction length (2 bytes), and raster data (dot data).

  The processing from step S630 to S660 of the command creation processing (FIG. 17) is repeatedly executed until all the ink colors used for forming the color image are completed. That is, when there is an ink color that is not yet a target of processing (step S670: No), one ink color that is not a target of processing is selected, and steps S630 to S660 are selected for the selected ink color. Processing is executed. When the processing for all inks is completed (step S670: Yes), the creation of raster commands corresponding to each of the ink colors used to form a color image is completed for one raster.

  Next, the command creation module 370 (FIG. 4) creates a raster command corresponding to the toned white image through the processing from step S680 (FIG. 17) to S720. In step S680, the command creation module 370 creates a horizontal position designation command for the selected one ink color based on the toned white image dot data. The horizontal position designation command is a command for designating the start position of the image along the horizontal direction (X direction) for one ink color when forming the toned white image. The command creation module 370 refers to the toned white image dot data for one ink color, sets an appropriate image start position, and creates a horizontal position designation command.

  In step S690 (FIG. 17), the command creation module 370 (FIG. 4) extracts dot data for one raster for one selected ink color from the toned white image dot data. In step S700, the command creation module 370 searches for an ink code with reference to the ink code table ICT. The command creation module 370 searches the ink code for the toned white image in the ink code table ICT (FIG. 19).

  In Step S710 (FIG. 17), the command producing module 370 (FIG. 4), based on the one raster the searched ink code dot data retrieved, to create a raster command (see FIG. 18 (b)) . The processing from step S680 to step S710 of the command creation processing is repeatedly executed until all the ink colors used for forming the toned white image are completed. That is, when there is an ink color that has not yet been processed (step S720: No), one ink color that has not been processed is selected, and steps S680 to S710 are performed for the selected ink color. Processing is executed. When the processing for all inks is completed (step S720: Yes), the creation of raster commands corresponding to each of the ink colors used for forming the toned white image is completed for one raster.

  The processing from step S620 to step S720 of the command creation processing (FIG. 17) is repeatedly executed until all rasters of the print image PI are completed. That is, when there is a raster that has not yet been processed (step S730: No), a raster that has not been processed (the raster that is one lower than the previous raster to be processed) is selected and selected. The process from step S620 to S720 is executed for the raster. When processing for all rasters is completed (step S730: Yes), creation of commands corresponding to each of the ink colors used for forming the color image and the toned white image is completed for all rasters.

  In step S260 in the process by the printer driver 300 (FIG. 9), the printer driver 300 transmits the print order designation command, the vertical position designation command, the horizontal position designation command, and the raster command created in step S250 to the printer 100. . Thus, the processing by the printer driver 300 is completed.

  In step S130 of the printing process (FIG. 6), the process by the printer 100 is executed. FIG. 20 is a flowchart showing the flow of processing by the printer 100. In step S810, the CPU 110 (FIG. 3) executing the command processing module 112 (FIG. 5) of the printer 100 receives a command transmitted from the printer driver 300 of the PC 200. CPU 110 determines the type of command received (step S820), and executes processing according to the type of command. If the received command is a printing order designation command, the CPU 110 stores information indicating the printing order designated by the printing order designation command in the RAM 130 (step S830), and the received command is a horizontal position designation command. In this case, the horizontal print start position X is updated (step S840).

  When the received command is a raster command, the CPU 110 (FIG. 3) that executes the command processing module 112 (FIG. 5) converts the raster data (dot data) included in the raster command into a raster buffer for each ink code. 132 (FIG. 5) (step S850). FIG. 21 is an explanatory diagram showing the detailed configuration of the raster buffer and the head buffer. The upper part of FIG. 21 shows a raster buffer 132c for a color image, and the middle part shows a raster buffer 132w for a toned white image. As shown in FIG. 21, the raster buffer 132 is assigned a region for each ink code (see FIG. 19). That is, the color image raster buffer 132c is configured as a set of regions corresponding to the color image ink codes, and the toned white image raster buffer 132w is also the toned white image ink code. It is comprised as a set of the area | region corresponding to each. The size in the X direction of each area of the raster buffer 132 corresponds to the image size, and the size in the Y direction is one half or more of the height of the print head 144. The raster buffer 132 has a raster buffer pointer in the Y direction that indicates how far raster data has been received.

  The lower part of FIG. 21 shows the head buffer 142 (FIG. 5). As shown in FIG. 21, the head buffer 142 is allocated with regions for each of seven ink colors. In other words, the head buffer 142 includes an area for cyan (for C and WC), an area for magenta (for M and WM), an area for yellow (for Y and WY), and an area for black (for K and WK). ), A light cyan (Lc, WLc) area, a light magenta (Lm, WLm) area, and a white (IW, W) area. The size in the X direction of each area of the head buffer 142 corresponds to the scanning distance of the carriage, and the size in the Y direction corresponds to the number of nozzles constituting the nozzle row 146 of the print head 144. Each region of the head buffer 142 for each ink color is divided into an upstream portion 142u and a downstream portion 142l.

  FIG. 22 is an explanatory diagram showing the configuration of the print head 144 of the printer 100. As shown in FIGS. 22A and 22B, the print head 144 is provided with nozzle rows 146 corresponding to the seven ink colors. The nozzle row 146 is formed so as to extend along the Y direction (print medium feeding direction). Further, as shown in FIG. 22C, each nozzle row 146 is composed of 32 nozzle groups arranged along the print medium feeding direction. Among the nozzle groups constituting the nozzle row 146, the nozzle group (from the first nozzle (nozzle 1) to the 16th nozzle (nozzle 16)) located in the upstream half along the print medium feeding direction is the upstream nozzle group. The nozzle group (from the 17th nozzle (nozzle 17) to the 32nd nozzle (nozzle 32)) located in the downstream half along the print medium feeding direction is called a downstream nozzle group.

  As shown in FIG. 22A, during WC printing, a toned white image is formed using the upstream nozzle group of each nozzle row 146 of the print head 144, and the downstream nozzle group is used. A color image is formed. Further, as shown in FIG. 22B, during C-W printing, a color image is formed using the upstream nozzle group of each nozzle row 146 of the print head 144, and the downstream nozzle group is used. A toned white image is formed.

  As shown in FIG. 21, the upstream head buffer 142u is a head buffer 142 corresponding to an upstream portion (upstream nozzle group) along the print medium feeding direction of the print head 144, and the downstream head buffer 142l is The head buffer 142 corresponds to a downstream portion (downstream nozzle group) along the print medium feeding direction of the print head 144.

  In step S850 of FIG. 20, the CPU 110 (FIG. 3) refers to the ink code included in the received raster command, and stores the raster data at the position specified by the raster buffer pointer of the raster buffer 132 corresponding to the ink code. To do. Therefore, the CPU 110 can distribute raster data to an appropriate raster buffer 132 without being aware of whether the raster command is for a color image or a toned white image.

  When the received command is a vertical position designation command, the CPU 110 (FIG. 3) that executes the command processing module 112 (FIG. 5) updates the print start position Y in the vertical direction (step S860). Next, the CPU 110 determines whether or not the raster buffer 132 corresponding to half the height of the print head 144 (FIG. 5) is full (that is, raster data is stored) (step S870). ). If it is determined that it is not yet full (step S870: No), the CPU 110 updates the raster buffer pointer of the raster buffer 132 (step S880).

  When the processing described above is repeated and raster data is stored in the raster buffer 132 corresponding to half of the height of the print head 144, the raster buffer corresponding to half of the height of the print head 144 is stored. It is determined that 132 is full (step S870: Yes). At this time, the CPU 110 (FIG. 3) determines whether the printing order is C-W printing or WC printing based on the information indicating the printing order stored in the RAM 130 (step S880). If it is determined that the printing order is C-W printing (step S880: Yes), the CPU 110 transfers raster data from the color image raster buffer 132c to the upstream head buffer 142u (FIG. 5), and Raster data is transferred from the toned white image raster buffer 132w to the downstream head buffer 142l (FIG. 5) (step S890). In FIG. 21, when the printing order is C-W printing, raster data is transferred from the color image raster buffer 132c to the upstream head buffer 142u, and the downstream head buffer from the toned white image raster buffer 132w. It shows how raster data is transferred to 142l. As a result, color image formation is performed using the upstream nozzle group of each nozzle row 146 of the print head 144, and toned white image formation is performed using the downstream nozzle group (FIG. 22B). )) Will be ready. Since the printing position on the physical paper is different between the upstream nozzle group and the downstream nozzle group, when the raster data is transferred from the raster buffer 132, the difference in the printing position between the upstream nozzle group and the downstream nozzle group is considered. Then, the transfer start data position on the raster buffer is determined.

  On the other hand, when it is determined that the printing order is WC printing (step S880: No), the CPU 110 transfers raster data from the color image raster buffer 132c to the downstream head buffer 142l (FIG. 5). At the same time, the raster data is transferred from the toned white image raster buffer 132w to the upstream head buffer 142u (step S900). Thereby, the toned white image is formed using the upstream nozzle group of each nozzle row 146 of the print head 144, and the color image is formed using the downstream nozzle group (see FIG. 22A). )) Will be ready.

  Next, the CPU 110 (FIG. 3) controls the print medium feed controller 160 and the print medium feed motor 162 to transport (sub-scan) the print medium PM to the head position Y (step S910) and the CR controller 150. Then, the CR motor 152 is controlled to move the print head 144 to the print start position X (step S920), and further, the main scan is performed to perform printing for the height of the print head 144 (step S930). At this time, in WC printing (see FIG. 22A), the formation of the toned white image by the upstream nozzle group (see FIG. 22C) of the nozzle row 146 of the print head 144 and the color image by the downstream nozzle group. Are formed in parallel. In C-W printing (see FIG. 22B), the color image formation by the upstream nozzle group of the nozzle row 146 of the print head 144 and the toned white image formation by the downstream nozzle group are executed in parallel. The

  Next, the CPU 110 (FIG. 3) clears the raster buffer pointer of the raster buffer 132 (step S940), determines whether or not the printing process for the entire print image PI has been completed (step S950), and the printing process is performed. The processes from step S810 to S940 are repeatedly executed until it is determined that the process has been completed. If it is determined that the printing process has been completed, the printing process (FIG. 6) ends.

  As described above, in the printing system 10 according to the present exemplary embodiment, it is possible to execute a printing process that forms a color image and a toned white image on the print medium PM using a plurality of colors including white. Here, in the printing system 10 of the present embodiment, the color of the toned white image Iw is approximated to the color of the simulation ink for each type of the simulation ink that is the white ink as the color target of the toned white image. An ink information table IIT including information indicating the correspondence between the gradation value of the white image and the gradation value of each ink color is preset and stored. Further, when the simulation ink is designated by the simulation ink selection process (step S212 in FIG. 9), each of the formation of the toned white image Iw is based on the contents of the ink information table IIT corresponding to the designated simulation ink. Since the gradation value (density value) of the ink color is determined, the color of the toned white image Iw can be easily approximated to the color of the simulation ink. That is, in the printing system 10 of the present embodiment, a dedicated LUT for the toned white image Iw is not provided, and the application program AP does not hold or change the data for white toning, and matches the simulation ink. A printing simulation can be performed. Therefore, even when the printing machine or printing ink corresponding to the target color of the simulation is changed, the printing simulation for the changed target color can be easily executed.

B. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

B1. Modification 1:
The configuration of the printing system 10 in the above embodiment is merely an example, and the configuration of the printing system 10 can be variously modified. For example, in the above embodiment, the printer 100 is a printer that performs printing using seven colors of ink of cyan, magenta, yellow, black, light cyan, light magenta, and white, but the printer 100 includes white. Any printer that performs printing using multiple colors of ink may be used. For example, the printer 100 may be a printer that performs printing using inks of five colors of cyan, magenta, yellow, black, and white.

  In the above embodiment, six colors of ink other than white are used for forming a color image, and no white ink is used. However, the ink color used for forming a color image can be used by the printer 100. It can be arbitrarily set according to various ink colors. For example, white ink may be used to form a color image.

  Further, in the above-described embodiment, five color inks of white, yellow, black, light cyan, and light magenta are used to form the toned white image, and two colors of cyan and magenta are not used. The ink color used for forming the toned white image only needs to include at least one color other than white and white, and can be arbitrarily set according to the ink color that can be used by the printer 100. For example, only four colors of white, yellow, light cyan, and light magenta may be used to form a toned white image, or white, yellow, black, light cyan, light magenta, cyan, and magenta. Color ink may be used.

  In the above embodiment, the printer 100 is a printer that performs printing while reciprocating (main scanning) the carriage on which the print head 144 is mounted. However, the present invention is a line printer that does not involve reciprocal movement of the carriage. It is also applicable to printing processing by

  In the above embodiment, the printer driver 300 is included in the PC 200, and the printer 100 receives a command from the printer driver 300 of the PC 200 and executes printing (see FIG. 4). However, the printer 100 is a printer driver. The printer 100 may include the same function as 300, and the printer 100 may receive the color image data Cdata, the white image data WIdata, and the print order designation information SS from the application program AP of the PC 200 and execute printing. Alternatively, the printer 100 may further include the same function as the application program AP, and the printer 100 may generate the color image data Cdata, the white image data WIdata, the print order designation information SS, and perform print processing.

  Further, the contents of the ink information table IIT and the color image lookup table LUTc in the above embodiment are merely examples, and these contents can be experimentally set in advance according to, for example, the composition of ink used in the printer 100. . Further, these contents can be variously modified according to the contents of data (used color space) output from the application program AP and the used ink color of the printer 100. Similarly, the contents of color conversion processing and ink color separation processing using these tables can be variously modified.

  In the above embodiment, the halftone processing module 320 (FIG. 4) performs halftone processing with reference to the dither pattern. However, halftone processing by another method such as an error diffusion method may be performed. . If the printer 100 can form dots of a plurality of sizes for each ink color, the dot ON / OFF and the dot size are not binarized for determining dot ON / OFF by halftone processing. Multi-value conversion may be performed.

  Further, the configuration of the printing order designation command and the raster command (FIG. 18) and the contents of the ink code table ICT (FIG. 19) in the above embodiment are merely examples and can be variously modified. In the above embodiment, the ink code uniquely corresponds to the combination of each of the plurality of ink colors and each of the color image and the toned white image, but the ink code is not necessarily in this way. It does not need to be set. However, if the ink code is set in this way, the CPU 110 of the printer 100 processes the command according to the ink code included in the raster command without being conscious of whether the raster command is for a color image or a toned white image. be able to.

  In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. Good.

  In addition, when part or all of the functions of the present invention are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but an internal storage device in a computer such as various RAMs and ROMs, a hard disk, etc. It also includes an external storage device fixed to the computer.

  Moreover, in the said Example, the printing process which forms the color image and the toned white image in parallel on the transparent film as the printing medium PM, and produces the printed matter in which the color image and the toned white image were formed. However, the print medium PM used in the printing process is not limited to a transparent film, and any medium such as a translucent film, paper, or cloth can be selected. When a transparent film is used as the print medium PM, the color image Ic can be formed as it is even in C-W printing (FIG. 8B).

  Further, the printer 100 in the above embodiment can execute a printing process for forming only a color image (including a color image formed using white ink). In this case, the nozzle row 146 of the print head 144 is executed. Printing is performed using the entire nozzle row 146 without dividing the upstream side and the downstream side (see FIG. 22). That is, the printer 100 uses the nozzle group 146 to form a color image and a nozzle group to form a toned white image only when performing a printing process for forming a color image and a toned white image. It is sufficient to divide into two types and perform printing.

  In the above embodiment, the printer driver 300 includes the simulation ink selection / ink color data generation module 330 (FIG. 4), but the application program AP may include the simulation ink selection / ink color data generation module 330. . In this case, the simulation ink selection process (step S212 in FIG. 9) and the ink color data generation process for white image (step S220 in FIG. 9) are executed not by the printer driver 300 but by the application program AP.

  In the above embodiment, the process of converting raster data (dot data) into the data transfer method to the print head 144 is executed by the command processing module 112 of the printer 100, but the process is executed by the printer driver 300. It may be done.

  In the above-described embodiment, the ink information table IIT is set for each combination of the simulation ink type and the printing order. However, the ink information table IIT is not related to the printing order and the simulation ink type. It may be set every time.

  In the above embodiment, the simulation ink is specified using the manufacturer name. However, the manufacturer name may be the manufacturer of the simulation ink itself, or the manufacture of the printing machine using the simulation ink. It may be a person's name. Further, when there is a possibility that one manufacturer name corresponds to a plurality of white inks, such as when a certain manufacturer manufactures a plurality of white inks, the simulation ink is used as the manufacturer name and the white ink. It may be specified using the type name.

10 ... Printing system 100 ... Printer 110 ... CPU
112 ... Command processing module 120 ... ROM
130 ... RAM
132: Raster buffer 140 ... Head controller 142 ... Head buffer 144 ... Print head 146 ... Nozzle array 150 ... Carriage controller 152 ... Carriage motor 160 ... Print medium feed controller 162 ... Print medium feed motor 170 ... USB interface 180 ... Network interface 200 ... PC
210 ... CPU
220 ... ROM
230 ... RAM
240 ... USB interface 250 ... Network interface 260 ... Display interface 270 ... Serial interface 280 ... Hard disk drive 290 ... CD drive 300 ... Printer driver 310 ... Color image ink color separation processing module 320 ... Halftone processing module 330 ... Simulation ink selection Ink color data generation module 332 ... UI control module 370 ... Command creation module

Claims (8)

A printing apparatus that performs printing using a plurality of colors of ink including white,
A first nozzle group that ejects ink to form a color image on the print medium; and at least one other than white and white to form a toned white image that is an adjusted white color on the print medium A head having a second nozzle group for ejecting ink of color;
A control unit that controls the head to form the color image and the toned white image on the print medium;
A designation information acquisition unit for acquiring designation information for designating one of a plurality of specific white inks as a color target of the toned white image;
An image data acquisition unit for acquiring white image data indicating a gradation value of the white image;
A storage unit configured to store correspondence information indicating a correspondence relationship between a gradation value of the white image and a gradation value for each ink color used in the printing apparatus, which is set in advance for each of the plurality of specific white inks; With
The control unit converts the white image data into data representing a gradation value for each ink color based on the correspondence information for the specific white ink designated by the designation information, and converts the level for each ink color. A printing apparatus that forms the toned white image using data representing a tone value. The printing apparatus according to claim 1,
The correspondence information is set so that the entire range of gradation values of the white image is associated with a partial range that does not include the maximum gradation value of the white ink with respect to at least one specific white ink. A printing device. The printing apparatus according to claim 1 or 2, wherein
It said plurality of specific white ink is an ink which is not used in the printing device, the printing device. The printing apparatus according to claim 3,
The specified information acquisition unit acquires information specifying at least one of a manufacturer of the specific white ink and a manufacturer of a printing machine in which the specific white ink is used as the specified information. The printing apparatus according to any one of claims 1 to 4,
The designation information includes printing order designation showing the print order of the color image and the toned-white image,
The printing apparatus, wherein the correspondence information indicates the correspondence set for each combination of the specific white ink and the printing order. A printing apparatus according to any one of claims 1 to 5,
The control unit is configured to form the color image using the first nozzle group and form the toned white image using the second nozzle group in at least a part of the printing period. A printing apparatus that controls the head so that the two are performed in parallel. The printing apparatus according to any one of claims 1 to 6,
The multi-color ink includes a combination of a light color ink and a dark color ink for at least one hue;
The printing apparatus in which the second nozzle group does not eject the dark ink. A first nozzle group that ejects ink to form a color image on the print medium; and at least one other than white and white to form a toned white image that is an adjusted white color on the print medium A printing method for controlling a head having a second nozzle group for ejecting ink of color and performing printing using a plurality of colors of ink including white,
(A) controlling the head to form the color image and the toned white image on the print medium;
(B) obtaining designation information for designating one of a plurality of specific white inks as a color target of the toned white image;
(C) obtaining white image data indicating a gradation value of the white image;
(D) A step of acquiring correspondence information indicating a correspondence relationship between a gradation value of the white image and a gradation value for each ink color used for printing, which is set in advance for each of the plurality of specific white inks. And comprising
The step (a) converts the white image data into data representing a gradation value for each ink color based on the correspondence information for the specific white ink designated by the designation information, and for each ink color a step of forming an image of the toned-white using the data representing the tone value, the printing method.

Images