JP4978534B2 - Image forming apparatus, image forming program, and computer-readable recording medium storing image forming program - Google Patents

Description

  The present invention relates to an image forming apparatus, an image forming program, and a computer-readable recording medium storing the image forming program, and more specifically, a print area other than an area where an original image is arranged can be made transparent. The present invention relates to an image forming apparatus, an image forming program, and a computer-readable recording medium storing the image forming program.

  2. Description of the Related Art Conventionally, an ink jet printing apparatus that uses ink for forming color pixels (hereinafter referred to as “color ink”) is known in order to perform printing on a printing medium with color. In this inkjet printing apparatus, color ink is guided from an ink supply source to a plurality of ejection channels of an inkjet head, and an actuator such as a heating element or a piezoelectric element is selectively driven, so that a nozzle provided at the tip of the ejection channel is used. Color ink is ejected. Then, for example, the color inks corresponding to the three primary colors of cyan (C), magenta (M), and yellow (Y) are adjusted according to the respective pixels forming the image, and color printing is performed. Yes. The black pixels are formed by mixing color inks or using black (K) ink.

  On the other hand, since white pixels cannot be formed with the above-described CMY three-primary color inks, normally, color ink is ejected to white pixel portions on a printing medium with a white background color. The method of expressing white is taken by not having. Also, printers that can use white (W) ink in addition to the above-described color inks are known, and if such a printer is used, even if the background color of the print medium is not white, the print medium It becomes possible to form white pixels on the top.

  When an image created by an application is printed by a printer, the printer driver converts image data (image data) output from the application into print data and transmits the print data to the printer. Specifically, individual objects (vector objects drawn in vector format or bitmap objects drawn in bitmap format) composing image data created by an application are converted into commands according to the format defined by the OS. And output from the application to the printer driver. In the printer driver, each received command is spooled, rasterized in order, and a print image corresponding to a printable area (a range in which printing can be performed on a printing medium) is made, for example, red (R), green ( G) Data (raster data) expressed by pixels having blue (B) as the three primary colors is created. Further, pseudo-gradation processing is performed on the created raster data, and each pixel is expressed by a print gradation with CMY as the three primary colors, thereby creating data (ejection map data) as a color ink ejection image. A printer control command or the like is added to the print data to create print data and transmit the print data to the printer. The printer that has received the print data created in this way performs printing by ejecting the color inks of the respective colors onto the print medium in accordance with the print data.

  Here, the size and shape of the image created by the application do not necessarily match the printable area. For this reason, generally, the area (image blank area) excluding the position where the image is arranged in the printable area is treated as a background color (usually white). In contrast, the discharge map data is generated so that the color ink is not discharged. However, when printing is performed with a printer using white ink, if the background color is treated as white, ejection map data for ejecting white ink to that pixel is created by the printer driver. Therefore, a color used as a background color in an application (for example, white mixed with a slight black) is distinguished from white, and the background color is set in advance as a transparent color that does not discharge color ink or white ink. Thus, it is possible to prevent white ink or the like from being ejected to an area other than the image arrangement position in the printable area (see, for example, Patent Document 1).

By the way, in the case of a printer using white ink, when the color of the background of the printing medium is not white, by discharging the color ink on top of the white ink previously discharged and printing the image, It is also possible to print a high-quality image that is not affected by the color or brightness of the background. In order to realize this, it is necessary to create print data in which white ink is ejected at a position where an image is arranged in a printable area, separately from normal print data creation in the printer driver. Therefore, when creating the raster data, the printer driver recognizes the layout position and size of the image in the print image for the printable area, and performs the mask processing on the image data to obtain the raster data for overlay. Create (for example, refer to Patent Document 2). Based on the created raster data for overlay, print data for printing the mask part as white and the other parts as transparent color is created and sent to the printer prior to normal print data to print with white ink. Just do it.
JP 2003-231300 A JP 2000-163238 A

  However, in Patent Document 1, there is a troublesome problem that the user has to specify a white portion for discharging white ink and a transparent color for preventing white ink from being discharged. Furthermore, when the image created by the application is smaller than the printable area, it is necessary to create image data of the printable area size by adding a background color. Some applications create and output a bitmap object in which an image and a background are integrated as an object to be output to a printer driver. A printer driver that has received such an object cannot specify at which position in the printable area and in which size the image is arranged (that is, the image and the background cannot be distinguished). There is a problem that it is impossible to create raster data for overlay.

  The present invention has been made to solve the above-described problems, and does not print the print area except the area where the original image is arranged, that is, it can be printed transparently and make use of the color of the printing medium. An object of the present invention is to provide an image forming apparatus, an image forming program, and a computer-readable recording medium storing the image forming program.

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention is an image forming apparatus that outputs image data as a basis for creating print data to a print data creating apparatus that creates the print data. Of the original image data input means for inputting the original image data which is the image data of the original image, and the image expression color which is the color used for expressing the image, the input by the original image data input means When the unused color is specified by the unused color specifying means for specifying the unused color that is the image expression color that is not used for the pixels constituting the original image data, and when the unused color is specified by the unused color specifying means, unused color, a first background color setting means for setting a background color to be used for the pixels constituting the background area that is the area other than the area where the original image is placed in the printable area, the unused When the unused color is not specified by the specifying unit, the specific image expression color of the pixel expressed by the specific image expression color used for the pixel constituting the original image data is changed to another image. A color changing means for changing to an expression color; a second background color setting means for setting the specific image expression color that has become the unused color as a result of the color change by the color changing means; wherein the background color set by the first background color setting means or the second background color setting means, use the pixels constituting the background area, placing the original image in the print area Image data creation means for creating image data of the image obtained, image data output means for outputting the image data created by the image data creation means to the print data creation device, and the background color, And a background color storage means whose serial print data creation apparatus and stores the possible background color storage means reference.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the color changing unit includes any one of the color components constituting the specific image expression color. The specific image expression color is changed to the other image expression color by changing a gradation value of a component.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect , the other image expression color is a pixel adjacent to a pixel where the specific image expression color is located. It is an image expression color used in the above.

Further, the image forming apparatus of the invention according to claim 4, in addition to the configuration of the invention according to any one of claims 1 to 3, wherein the non-use color identification means for each of said image representation color, the original image Count means for counting the number of times of use, which is the number of times used for the pixels constituting the data, and judgment means for determining whether there is the image expression color for which the number of times of use counted by the count means is zero And specifying means for specifying, as the unused color, the image expression color with the zero use count when the determination means determines that there is the image expression color with the use count of zero. Yes.

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect of the invention, the specific image expression color is the image expression color with the smallest number of uses counted by the counting means. It is characterized by being.

An image forming program according to a sixth aspect of the present invention is an image forming program used in an image forming apparatus that outputs image data that is a basis for creating print data to a print data creating apparatus that creates the print data. Of the original image data input step of inputting original image data which is image data of the original image, and the image expression color which is a color used for expressing the image, the input of the original image data in the original image data input step An unused color specifying step for specifying an unused color that is an image expression color that is not used for pixels constituting original image data, and when the unused color is specified in the unused color specifying step, The unused color is set as the background color used for the pixels constituting the background area, which is an area other than the area where the original image is arranged in the printable area. In the background color setting step of 1 and the unused color specifying step, when the unused color is not specified, the specific image expression color used for the pixel constituting the original image data is used. A color changing step of changing the specific image expression color of a pixel to another image expression color, and the specific image expression color that has become the unused color due to the color change in the color changing step is changed to the background color And using the background color set in the first background color setting step or the second background color setting step for the pixels constituting the background region. An image data creation step for creating image data of an image in which the original image is arranged in the print area; and the image data created in the image data creation step. The controller of the image forming apparatus includes: an image data output step for outputting a data to the print data creation device; and a background color storage step for storing the background color in a background color storage means that can be referred to by the print data creation device. Contains instructions for execution.

According to a seventh aspect of the present invention, there is provided a computer-readable recording medium having an image forming program used in an image forming apparatus for outputting image data as a basis for generating print data to a print data generating apparatus for generating the print data. The image forming program stores an original image data input step for inputting original image data, which is image data of the original image, and a color used for expressing the image. Among the image expression colors, an unused color specifying step for specifying an unused color that is the image expression color that is not used for the pixels constituting the original image data input in the original image data input step; When the unused color is specified in the unused color specifying step, the unused color is changed to the original image in the printable area. When the unused color is not specified in the first background color setting step that is set as a background color to be used for the pixels constituting the background region that is a region other than the region where the non-used color is arranged, and the unused color specifying step A color changing step of changing the specific image expression color of the pixel expressed by the specific image expression color used for the pixel constituting the original image data to another image expression color; and the color change A second background color setting step for setting the specific image expression color that has become the unused color as a background color by changing the color in the step; and the first background color setting step or the second background color setting step. Using the background color set in the background color setting step for the pixels constituting the background area, image data of an image in which the original image is arranged in the print area is created. An image data creation step, an image data output step for outputting the image data created in the image data creation step to the print data creation device, and a background color that can be referred to by the print data creation device An instruction for causing the controller of the image forming apparatus to execute a background color storing step to be stored in the storage unit.

In the image forming apparatus according to the first aspect, among the image expression colors used for expressing the image, the unused colors that are not used for the pixels constituting the original image data are the original colors in the printable area. It is set as the background color used for the background area that is an area other than the area where the image is placed. Then, using the background color for the background area, the image data of the image in which the original image is arranged in the printable area is output to the print data creating apparatus, and the background color is stored in the background color storage means. Thereby, the print data creation device can create print data set not to print in the background area based on the output image data and the background color stored in the background color storage means. It becomes. In this way, since the unused color specified based on the original image data is automatically set to the background color that is a transparent color, the user specifies a background region other than the region where the original image is arranged. The background area can be made transparent even if the transparent color is not specified. In particular, when printing with a printer using white ink, there is no risk that the background area will be automatically printed with white ink, and printing utilizing the color of the print medium is possible, enabling more diverse users. Can meet your needs. In addition, since it is not necessary to previously determine a transparent color that is not used for the original image, the color used for the original image is not limited. Further, in the image forming apparatus, when the unused color is not specified, the specific image expression color used for the pixels constituting the original image data is changed to another image expression color. As a result, a specific image expression color that is an unused color is set as the background color. Therefore, in addition to the effect of the invention according to claim 1, even when there is no unused color as it is, the unused color is created and used as the background color, so that the background area can be automatically made transparent.

In the image forming apparatus according to the second aspect of the present invention, when an unused color is not specified, the specific color expression component is specified by changing the tone value of any one of the color components constituting the specific image expression color. The image expression color of is changed to another image expression color. Therefore, in addition to the effect of the invention described in claim 1 , an unused color can be created by color change that is not unnatural from the viewpoint of the user.

In the image forming apparatus according to the third aspect , when the unused color is not specified, the specific image expression color is changed to the image expression color of the pixel adjacent to the pixel where the specific image expression color is located. Adjacent pixels often have approximate colors, and for one pixel, there is no significant difference in area even if the same color continues to increase. Therefore, in addition to the effect of the invention described in claim 1 or 2 , an unused color can be created by a color change that is not recognized as a change in the color of the original image from the viewpoint of the user.

In the image forming apparatus according to the fourth aspect of the invention, in specifying the unused color, the number of uses used for all the pixels is counted for each of the image representation colors, and the image representation color having the number of uses of zero is counted. If there is, the image expression color is specified as an unused color. Therefore, in addition to the effects of the invention according to any one of claims 1 to 3 , an unused color can be easily specified with a simple configuration.

In the image forming apparatus according to the fifth aspect , the pixel of the image expression color that is least used is changed to another image expression color. That is, among the pixels constituting the original image data, the number of pixels whose color is changed is minimized. Therefore, in addition to the effect of the invention according to the fourth aspect , the user can create an unused color by a color change that cannot be recognized by the user as a color change of the original image.

The image forming program according to claim 6 of the present invention can cause a computer to function as various processing means of the image forming apparatus according to claim 1 . Therefore, by causing the computer to execute the image forming program, the effect of the invention of claim 1 can be achieved.

A computer-readable recording medium according to a seventh aspect of the present invention stores the image forming program according to the sixth aspect . Therefore, the effect of the invention of claim 1 can be achieved by causing the computer to read and execute the image forming program.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. As an image forming apparatus according to the present invention, a known personal computer 100 that creates image data as a basis of print data for causing a known inkjet printer 1 for fabric printing (see FIGS. 1 and 2) to execute printing. (See FIG. 3).

  First, the inkjet printer 1 will be described with reference to FIG. FIG. 1 is a plan view of the inkjet printer 1. As shown in FIG. 1, the inkjet printer 1 includes a flat plate-like base 2 having a longitudinal direction in the left-right direction on the bottom surface, and a box-shaped main body cover 3 that covers the entire apparatus. A rail 4 extending in the front-rear direction is disposed substantially at the center of the base 2, and the rail 4 can move a replaceable flat platen 5 in the front-rear direction (sub-scanning direction) of the base 2. I support it. A platen drive motor 7 that is a stepping motor for moving the platen 5 along the rail 4 is disposed at the rear end of the rail 4. The platen 5 is a substantially rectangular plate-like member whose longitudinal direction is the front-rear direction of the base 2, and a printing medium made of a fabric such as a T-shirt is placed on the upper surface of the platen 5 in parallel.

  In addition, on the back side (upper side in FIG. 1) above the platen 5 and inside the main body cover 3, a first carriage 10 for guiding the first carriage 10 on which the four inkjet heads 11 to 14 are mounted in the left-right direction. A guide rail 16 is installed. A first carriage motor 17 is provided near the left end of the first guide rail 16, and a pulley (not shown) is provided near the right end. A carriage belt (not shown) is provided between the first carriage motor 17 and the pulley. ) Is built. The carriage belt is fixed to the first carriage 10, and when the first carriage motor 17 is driven, the first carriage 10 fixed to the carriage belt moves along the first guide rail 16 in the left-right direction (main scanning). Direction).

  A first ink cartridge accommodating portion 30 that accommodates four ink cartridges 31 to 34 is disposed at the right end portion of the main body cover 3. The ink cartridges 31 to 34 are connected to the inkjet heads 11 to 14 mounted on the first carriage 10 by ink supply tubes 36 having appropriate flexibility. In the inkjet printer 1, all of the inkjet heads 11 to 14 of the first carriage 10 are provided for ejecting white (W) ink, and the four ink cartridges 31 to 34 all store white ink. Yes.

  A second guide rail 26 for guiding the second carriage 20 in the left-right direction is provided above the platen 5 and on the front side (lower side in FIG. 1) inside the main body cover 3. 16 is laid in parallel with 16. The second carriage 20 is equipped with four inkjet heads 21 to 24, and similarly to the first carriage 10, a carriage belt (not shown) provided between the second carriage motor 27 and a pulley (not shown). Move in the horizontal direction (main scanning method).

  A second ink cartridge housing portion 40 that houses four ink cartridges 41 to 44 is disposed at the left end portion of the main body cover. The ink cartridges 41 to 44 are connected to the inkjet heads 21 to 24 mounted on the second carriage 20 by ink supply tubes 46. The four inkjet heads 21 to 24 of the second carriage 20 are provided to eject each of cyan (C) ink, magenta (M) ink, yellow (Y) ink, and black (K) ink. Each of the cartridges 41 to 44 contains cyan ink, magenta ink, yellow ink, and black ink.

  Each of the inkjet heads 11 to 14 and 21 to 24 mounted on the first carriage 10 and the second carriage 20 is provided with, for example, 128 ejection channels (not shown) for ejecting ink. Each discharge channel is provided with a piezoelectric actuator (not shown) that is driven separately. Further, fine nozzles (not shown) are formed in the bottom surfaces of the respective inkjet heads 11 to 14 and 21 to 24 so as to correspond to the respective ejection channels, and ink droplets are ejected downward from these nozzles. Is done. Note that a capping mechanism, a purge mechanism, and the like (not shown) that perform maintenance of the inkjet heads 11 to 14 and 21 to 24 are provided at either of the left and right ends in the movement range of the carriages 10 and 20.

  An operation panel 50 for operating the ink jet printer 1 is disposed at a position on the right side of the ink jet printer 1. The operation panel 50 is provided with a display 51, a print start button 52, a print stop button 53, a platen feed button 54, an arrow button 55, an error lamp 56, a data reception lamp 57, and the like. The display 51 displays various images such as an operation screen, the print start button 52 is a button for starting printing, and the print stop button 53 is a button for stopping printing operation. The platen feed button 54 is a button for moving the platen to a position where the cloth can be placed on or removed from the platen 5, and the arrow button 55 is used when the user selects a menu or the like. Used. An error lamp 56 indicates that an error has occurred due to light emission, and a data reception lamp 57 indicates that print data has been received.

  Next, the electrical configuration of the inkjet printer 1 will be described with reference to FIG. FIG. 2 is a block diagram showing an electrical configuration of the inkjet printer 1. As shown in FIG. 2, the inkjet printer 1 is provided with a CPU 60 that controls the inkjet printer 1. A ROM 61, a RAM 62, a head drive unit 71, a motor drive unit 72, a display control unit 76, an input detection unit 77, and a USB interface 79 are connected to the CPU 60 via a bus 65.

  The ROM 61 includes a program storage area that stores a control program for controlling the operation of the inkjet printer 1, a print execution program for executing print processing, and settings, initial values, data, and the like necessary for executing the program. And a program-related information storage area for storing the above information. The ROM 61 is provided with other various storage areas.

  The RAM 62 includes a received print data storage area for storing print data received from the personal computer 100, a printing data storage area for storing print data that is being printed when the print start button 52 is pressed, and other various storage areas. Is provided.

  The head drive unit 71 is connected to the inkjet heads 11 to 14 and 21 to 24 that discharge ink. And the piezoelectric actuator provided in each discharge channel of each inkjet head 11-14, 21-24 is driven.

  The motor drive unit 72 includes a first carriage motor 17 that operates the first carriage 10, a second carriage motor 27 that operates the second carriage 20, and a platen roller (not shown) that adjusts the timing and speed at which the platen 5 is sent out. Is connected to a platen drive motor 7 for operating the. Then, these motors are driven.

  The display control unit 76 is connected to the display 51, the error lamp 56, the data reception lamp 57, and the like, and performs these display processes under the control of the CPU 60. The input detection unit 77 is connected to a print start button 52, a print stop button 53, a platen feed button 54, an arrow button 55, and the like, and detects these inputs. The inkjet printer 1 is connected to external devices including the personal computer 100 by the USB interface 79.

  With such a configuration, the inkjet printer 1 according to the present embodiment receives the print data created by the printer driver from the personal computer 100 and then places the fabric on the platen 5 by the user and prints the start button. When 52 is pressed, the printing process is started. In the printing process, first, the platen 5 is moved to the rear side (back side) of the main body by driving the platen drive motor 7 so that the moving path of the first carriage 10 that discharges white ink becomes the recording start position. Next, the ink jet printer 1 ejects white ink by the ink jet heads 11 to 14 according to the white (W) data in the print data (CMYKW) while moving the first carriage 10 in the left-right direction. Make a record. Then, the platen 5 is moved forward by one line to record the next line, and white printing is completed by repeating these operations. Next, the inkjet printer 1 moves the platen 5 forward so that the movement path of the second carriage 20 is at the recording start position, and causes the second carriage 20 to perform the same operation as the first carriage 10. Color ink (CMYK) is discharged. When the color printing is completed, the platen 5 is moved forward to a position where the cloth can be removed, and the printing process is terminated. Note that the four inkjet heads 11 to 14 that discharge white ink are controlled based on two-tone data of W in the print data. That is, the W data in the print data is used in common by the four inkjet heads 11 to 14 for white ink.

  Next, the personal computer 100 will be described with reference to FIGS. FIG. 3 is a block diagram showing an electrical configuration of the personal computer 100, and FIG. 4 is a schematic diagram showing a configuration of the RAM 112 of the personal computer 100. FIG. 5 is a schematic diagram showing a configuration of a hard disk drive (hereinafter referred to as “HDD”) 116 of the personal computer 100. The personal computer 100 is connected to the inkjet printer 1 by a communication cable based on a standard such as USB. In the personal computer 100, print data is created based on image data created by the user using various applications, and the print data is transmitted to the inkjet printer 1 for printing.

  As shown in FIG. 3, the personal computer 100 is provided with a CPU 110 that controls the personal computer 100. A ROM 111, a RAM 112, a CD-ROM drive 115, an HDD 116, a display control unit 126, an input detection unit 127, and a USB interface 129 are connected to the CPU 110 via a bus 114.

  The ROM 111 stores programs such as BIOS executed by the CPU 110. A CD-ROM 131 that is a recording medium is inserted into the CD-ROM drive 115, and data recorded on the CD-ROM 131 is read by the CD-ROM drive 115. The CD-ROM 131 stores an image data creation program according to the present invention, a printer driver in which a print data creation program is incorporated, and data such as settings and tables used when the program is executed. The program and data read by the CD-ROM drive 115 are stored in various storage areas provided in an HDD 116 (see FIG. 5) described later.

  The display control unit 126 is connected to a monitor 133 for displaying an operation screen, and controls the display of the monitor 133. The input detection unit 127 is connected to a keyboard 135 and a mouse 136 for a user to input an operation, and detects these inputs. The personal computer 100 is connected to an external device including the ink jet printer 1 through the USB interface 129, and data can be transmitted and received.

  Note that the configuration of the personal computer 100 in this embodiment is a general form, and the connection between the personal computer 100 and the inkjet printer 1 can also be made via a network. Further, data recorded on the CD-ROM 131 may be read by a DVD-ROM drive.

  As shown in FIG. 4, the RAM 112 has an original image data storage area 1121, a color use count storage area 1122, a background color storage area 1123, a background color image data storage area 1124, an original image pasting data storage area 1125, a conversion CMKYW. A data storage area 1126 and a print data storage area 1127 are provided.

  In the original image data storage area 1121, original image data that is image data of an original image to be printed is temporarily stored. The color use count storage area 1122 stores the color use count, which is the number of times used for pixels constituting the original image data, for each color expressed in 256 gradations in the sRGB format. The background color storage area 1123 stores a color (hereinafter referred to as a background color) used for an area (hereinafter referred to as a background area) other than an area where an original image is arranged within a printable area corresponding to the paper size. Is done. The background color image data storage area 1124 stores data of an image in which the entire printable area is filled with the background color (hereinafter referred to as background color image data). The original image pasting data storage area 1125 stores image data created by pasting original image data to the background color image data 140 (hereinafter referred to as original image pasting data). The converted CMYKW data storage area 1126 stores data converted from sRGB format image pasting data to CMYKW format (hereinafter referred to as converted CMYKW data). The print data storage area 1127 stores print data created from converted CMYKW data expressed in 256 gradations through pseudo gradation processing. The print data expresses the color of each pixel with two gradations (whether ink is ejected) in the CMYKW format.

  As shown in FIG. 5, the HDD includes a program storage area 1161, a program related information storage area 1162, a color conversion table storage area 1163, a white conversion table storage area 1164, an image data storage area 1165, a background color storage area 1166, and the like. Various storage areas are provided.

  The program storage area 1161 stores programs for various processes executed by the personal computer 100 including an image editing application, an image data creation program, and a printer driver (print data creation program). The program related information storage area 1162 stores information such as settings, initial values, and data necessary for program execution. The color conversion table storage area 1163 stores a color conversion table for converting color information of the original image data expressed by the RGB space into information of a level expressed by the CMYK space. The white conversion table storage area 1164 stores a white conversion table for converting color information of original image data into white ink level (W value) information. The image data storage area 1165 stores a plurality of original image data. The original image data is image data created by an image editing application or the like. The background color storage area 1166 stores the background color. The background color storage area 1166 corresponds to “background color storage means” of the present invention.

  Next, an image data creation process and a print data creation process related thereto, which are features of the present invention, will be described with reference to FIGS. FIG. 6 is a flowchart of image data creation processing performed by the personal computer 100, and FIG. 7 is a flowchart of print data creation processing. FIG. 8 is an explanatory diagram for explaining the relationship between the original image 182, the printable area 181, and the background area 183. FIG. 9 is an explanatory diagram of an image 185 corresponding to the original image pasting data. Hereinafter, each step of the flowchart is abbreviated as “S”.

  As described above, the inkjet printer 1 of the present embodiment can perform printing using white ink in addition to CMYK color inks. Accordingly, it is possible to form white pixels on a print medium (for example, fabric) such as black, and after forming a white background, color pixels may be formed on the background. it can. As a result, a high-quality image can be printed regardless of the color of the printing medium. However, in the inkjet printer 1, for example, as shown in FIG. 8, the background area 183 that is an area other than the original image 182 in the printable area 181 of the inkjet printer 1 is automatically white unless otherwise specified. Will be printed. Therefore, it is necessary to specify whether printing is actually performed in white or nothing is printed (transparent). Therefore, in the present embodiment, image data creation processing shown in FIG. 6 is performed as pre-processing for creating print data by the printer driver.

  When the user designates desired original image data and gives an instruction to execute printing, the image data creation process shown in FIG. 6 is started. The image data creation process is executed by the CPU 110 based on an image data creation program.

  As shown in FIG. 6, when the image data creation process is started, the original image data designated as the print target is read from the image data storage area 1165 of the HDD 116 and is stored in the original image data storage area 1121 of the RAM 112. Stored (S1). The original image data is, for example, image data of the original image 182 shown in FIG. 8 created by an image editing application. In the present embodiment, it is assumed that the original image data represents the color of each pixel with 256 gradations in the sRGB format. The sRGB format is an international standard for a color space defined by IEC (International Electrotechnical Commission). Next, the original image data is resampled by a known method in accordance with the print resolution (S2). As a resampling method, for example, a bicubic method can be employed.

  Next, for each color expressed in 256 gradations in the sRGB format, the number of times used for the pixels constituting the re-sampled original image data is counted (S5). Specifically, for example, the sRGB value of a color expressed in 256 gradations is a combination of an R value, a G value, and a B value, and is approximately 1,677,000. These sRGB values are read in order, and the number of pixels in the original image data in which the sRGB values that match the read sRGB values are used is counted as the number of times the color is used. The counted color usage count is stored in the color usage count storage area 1122 in association with the sRGB value. In the present embodiment, the sRGB value of a color expressed with 256 gradations corresponds to an “image expression color”.

  In S5, after the number of times of color use corresponding to all sRGB values is counted, it is determined whether or not there is a color whose color use number is zero (0) (S7). Specifically, it is determined whether or not the sRGB value for which the corresponding color usage count is zero is stored in the color usage count storage area 1122. If there is an sRGB value for which the corresponding color usage count is zero (S7: YES), the sRGB value is specified as an unused color that is not used in the original image (S12). Subsequently, the unused color is set as the background color to be used for the background area and stored in the background color storage area 1123 (S13). Specifically, if there is one unused color specified in S12, that unused color is set as the background color, and when a plurality of unused colors are extracted, one of them is arbitrarily selected. And set as the background color. For example, if the sRGB value is stored in the color usage count storage area 1122 with the color usage count corresponding to “R = 63, G = 63, B = 63” being zero (S7: YES), it is an unused color. A certain “R = 63, G = 63, B = 63” is stored in the background color storage area 1123 as a background color (S12, S13).

  On the other hand, when it is determined that there is no color whose number of times of color use is zero (S7: NO), all the sRGB values are used for any of the pixels constituting the original image data, and the unused color is not changed as it is. That is not. Therefore, in order to dare to provide an unused color, the color of the pixel in which the color with the smallest number of color uses is used is replaced with another color (S9). Specifically, first, of the sRGB values stored in the color usage count storage area 1122, the sRGB value with the smallest number of corresponding color usages is selected as a change target. In addition, when there are a plurality of sRGB values corresponding to the smallest number of color uses, one of them may be arbitrarily selected. When pixels constituting the original image data stored in the original image data storage area 1121 are noticed in order, and the sRGB value selected as a change target is used, the sRGB value of the pixel Is replaced by the sRGB value. The other sRGB values can be, for example, any one component in the sRGB color space, that is, a value obtained by changing one gradation value of any one of the R value, the G value, and the B value. For example, when the sRGB value with the smallest number of color uses is “R = 0, G = 0, B = 0”, only one of the R value, G value, and B value is changed to “1”. R = 1, G = 0, B = 0 ”,“ R = 0, G = 1, B = 0 ”, or“ R = 0, G = 0, B = 1 ”. In this way, by replacing the sRGB value of the pixel in which the sRGB value with the least number of color uses is used, the replaced sRGB value with the least number of color use times (in the above example, “R = 0, The number of times the color is used is “G = 0, B = 0”). That is, the sRGB value that is the change target is an unused color. Therefore, the color that has become the unused color and has the smallest number of color uses counted in S5 is set as the background color and stored in the background color storage area 1123 (S11). As described above, when the pixel having the least number of times of color use is changed to a color in which the gradation value of any one component in the sRGB color space is different by one, the color of the original image is changed by the user. The color can be changed to an extent that cannot be recognized.

  Next, background color image data in which the entire printable area is filled with the background color is created (S17). Specifically, image data of an image having a printable area size of the inkjet printer 1 is created using the sRGB values set as the background color in S11 or S13 and stored in the background color storage area 1123 for all pixels. The Subsequently, the original image pasted data is created by pasting the resampled original image data to the background color image data (S18). Specifically, the original image is arranged at an arbitrary position in the printable area, and the sRGB values of the pixels constituting the area where the original image is arranged among all the pixels constituting the printable area are the original image. Is replaced with the sRGB value used in. As a result, in the printable area, the color of the pixels constituting the background area, which is an area other than the area where the original image is arranged, is the background color, and the pixels constituting the area where the original image is arranged are the original image The color of the street. For example, when “R = 0, G = 0, B = 0” is set as the background color, the background area 183 that is the printable area 181 other than the original image 182 is filled with black as shown in FIG. Original image pasting data corresponding to the image 185 is created. The original image pasting data is stored in the original image pasting data storage area 1125.

  Subsequently, the original image pasting data created in S18 is output to the printer driver through the OS (S19). Further, after the background color (sRGB value) set in S11 or S13 and stored in the background color storage area 1123 is stored in the background color storage area 1166 of the HDD 116 (S20), the image data creation processing in FIG. finish.

  Next, the print data creation process will be described with reference to FIG. When the user instructs execution of printing of desired original image data, the printer driver is activated. Then, based on the print data creation program in the program for operating the printer driver, the CPU 110 starts print data creation processing.

  As shown in FIG. 7, in the print data creation process, first, the original image pasting data created in S18 of the image data creation process (see FIG. 6) is input through the OS and stored in the original image pasting data in the RAM 112. It is stored in the area 1125 (S21). Next, the background color (sRGB value) is read from the background color storage area 1166 of the HDD 116 and stored in the background color storage area 1123 of the RAM 112 (S23). The background color stored in the background color storage area 1166 of the HDD 116 is cleared (S25).

  Next, one of the plurality of pixels constituting the original image pasting data is sequentially set as a target pixel (S27). Based on whether the background color (sRGB value) read in S23 matches the sRGB value of the target pixel, it is determined whether the color of the target pixel is the background color (S31). For example, when the original image pasting data corresponding to the image 185 shown in FIG. 9 is input in S21 and “R = 0, G = 0, B = 0” indicating black is read as the background color in S23 The background color (black) is not used for the pixels constituting the original image 182. Therefore, if the pixel of interest is a pixel constituting the original image and the color is not the background color (S31: NO), the 256th floor expressing the color of the pixel of interest is printed in order to perform printing according to the color of the original image. The key sRGB values are converted into 256-tone CMYKW values based on the CMYKW format. The CMYKW format is a color expression method using five colors of cyan (C), magenta (M), yellow (Y), black (K), and white (W), and includes C value, M value, Y value, The color of each pixel is expressed by 256 gradations of K value and W value, and the ejection amount of each ink is determined. For the conversion from the sRGB value to the CMYKW value, a color conversion table and a white conversion table that are created by a known method and stored in advance in the color conversion table storage area 1163 and the white conversion table storage area 1164 of the HDD 116 may be used. . More specifically, the sRGB value data is converted into color ink level data in CMYK format and white ink level data in W format using a color conversion table and a white conversion table, respectively. The CMYK value of color ink level data and the W value of white ink level data constitute converted CMYKW data of 256 gradations. The CMKYW values obtained by such conversion are sequentially stored in the converted CMYKW data storage area 1126, and constitute converted CMYKW data.

  On the other hand, if the color of the target pixel is the background color (S31: YES), the target pixel is a pixel constituting the background region. Therefore, conversion to CMYKW values is performed in which all gradation values of C, M, Y, K, and W of the target pixel are set to zero (S33). The fact that all of the C value, M value, Y value, K value, and W value are zero means that neither color ink nor white ink is ejected. Therefore, the target pixel having the same color as the background color, that is, the pixel constituting the background area is set to be printed with neither color ink nor white ink.

  Then, all the pixels constituting the original image pasting data are noticed, and it is determined whether or not conversion processing to CMYKW values has been performed (S35). If all the pixels have not been processed (S35: NO), the process returns to S27, and the process for the next pixel is performed (S27 to S33). When the processing of S27 to S33 is completed for all the pixels (S35: YES), all of the C value, M value, Y value, K value, and W value of the pixels constituting the background area are changed to zero and transparent. Will be set. In such a state, pseudo gradation processing is performed on the converted CMYKW data stored in the converted CMYKW data storage area 1126 by a known method (S37). For example, an error diffusion method can be employed as the pseudo gradation processing method. The converted CMYKW data expressed in 256 gradations in the CMYKW format is converted into print data expressed in 2 gradations in the CMYKW format by the pseudo gradation processing, and stored in the print data storage area 1127 of the RAM 112. In the present embodiment, the print data represents whether or not to eject ink with two gradations. Then, the print data creation process shown in FIG. 7 ends.

  As described above, according to the personal computer 100 of the present embodiment, the number of times used for the pixels constituting the original image data to be printed is counted for each color expressed in the sRGB format. As a result, if there is an unused color whose use count is zero, the unused color is set as the background color which is the color of the background area. If there is no unused color, the color of the pixel in which the color that is used the least number of times is used is changed to a value in which one of the gradation values of R, G, and B is different, and this color change causes the unused color The color with the least number of uses is set as the background color. Thereafter, the original image data is pasted on the background color image data in which the printable area is filled with the background color, thereby creating the original image pasting data. Then, the original image pasting data is converted into converted CMYKW data. As a result, the background area portion is not printed, that is, can be printed as transparent. Therefore, even if the user specifies a background area other than the area where the original image is arranged and does not particularly specify the background color as a transparent color, the user can make the background area transparent without printing. In addition, printing that makes use of the color of the printing medium becomes possible, and more diverse user needs can be met.

  In the above embodiment, the personal computer 100 corresponds to the “image forming apparatus” and the “print data creating apparatus” of the present invention. More specifically, the personal computer 100 in which the image data creation program for creating and outputting the original image pasting data corresponding to the printable area based on the original image data is installed corresponds to the “image forming apparatus”. . Further, the personal computer 100 installed with a printer driver that creates print data based on the original image pasting data created by the image data creation program corresponds to a “print data creation device”.

  Further, the CPU 110 that reads the original image data from the original image data storage area 1121 in S1 of FIG. 6 functions as the “original image data input means” of the present invention. In S5, S7, and S12 of FIG. 6, the CPU 110 that specifies an unused color functions as an “unused color specifying unit”. In S5 of FIG. 6, the CPU 110 that counts the number of times used for the pixels constituting the original image data for the color represented by each sRGB value functions as a “counting unit”. In S7, the color that is not used The CPU 110 that determines the presence / absence of the color functions as “determination means”, and the CPU 110 that identifies the unused color in S12 functions as “specification means”. In S13 of FIG. 6, the CPU 110 that sets the unused color as the background color functions as the “first background color setting means” of the present invention.

  In S9 of FIG. 6, when there is no unused color, the CPU 110 that changes the color with the smallest number of color use times to another color functions as the “color changing means” of the present invention. In S11 of FIG. 6, the CPU 110 that sets the color that has become the unused color as a result of the color change in S9 as the background color as the background color functions as the “second background color setting unit” of the present invention. To do. Further, in S17 and S18 of FIG. 6, the CPU 110 that creates the original image pasting data by creating the background color image data and pasting the original image data on the background color image data is the “image data creation” of the present invention. Functions as a means. In S19 of FIG. 6, the CPU 110 that outputs the original image pasting data created in S17 and S18 to the printer driver through the OS functions as an “image data output unit”. In S20 of FIG. 6, the CPU 110 that stores the background color in the background color storage area 1166 functions as a “background color storage unit”.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above embodiment, for all sRGB values used to represent an image, the number of times used for the pixels constituting the original image is counted in order, and there may be colors where the number of uses is zero. For example, the color is specified as an unused color and set as a background color (FIG. 6, S5, S7: YES, S12, S13). However, the specification of the unused color is not limited to the above example, and may be performed by other methods. For example, first, one sRGB value is arbitrarily selected from all sRGB values used to represent an image. Then, it is determined whether or not the selected sRGB values are used in order for all the pixels constituting the original image. When a pixel in which the selected sRGB value is used is found, it can be determined that the sRGB value is not an unused color, so the next sRGB value is selected. Similarly, it is determined whether or not the selected sRGB value is used in order for all the pixels constituting the original image. As a result, if the selected sRGB value is not used in all pixels, this sRGB value can be specified as an unused color.

  In the above embodiment, when an unused color is not specified as a result of searching for an unused color based on the original image data (FIG. 6, S5, S7: NO), the color with the smallest number of uses is used. An unused color is created by replacing the color of the current pixel with another color. In the above embodiment, the color that is used the least number of times can be replaced with any one component in the RGB color space, that is, a value obtained by changing one gradation value among the R value, G value, and B value. ing. However, the other colors after replacement do not necessarily have to be a value obtained by changing one gradation value among the R value, the G value, and the B value, and it is recognized from the user that the color of the original image has changed. Any color that is as natural as possible is acceptable. For example, any one of the R value, the G value, and the B value can be changed to an arbitrary value of 10 or less. Alternatively, not only one of R value, G value, and B value, but a plurality of (for example, R value and G value) gradation values may be changed one by one. Or you may replace with the color of the pixel located next to the pixel in which the color with the least frequency of use is used. Adjacent pixels often have approximate colors, and for one pixel, there is no significant difference in area even if the same color continues to increase. Therefore, an unused color can be created with a color change that is not recognized as a change in the color of the original image from the viewpoint of the user.

  In addition, when an unused color is not specified, a color that is replaced with another color does not necessarily need to be a color that is used the least number of times. For example, a color that is empirically known to be less likely to be used in the color space may be stored in a predetermined storage area of the HDD 116, for example. And when an unused color is not specified, a color change can be performed about the pixel in which this color is used.

  In the above-described embodiment, the case where the original image data in the sRGB format is converted into the data in the CMYKW format by the color conversion table and the white conversion table is exemplified, but such a data format can be arbitrarily changed. For example, the original image data may be data expressed in another color space such as CMYK format or HSV format. The color conversion table and the white conversion table need only define the correspondence of the data format so as to enable conversion of the original image data. Also, the data format of the print data can adopt other data formats such as CMYW format. Furthermore, the gradation of data is not limited to 256 gradations.

  Further, the configuration of the ink jet printer 1 can be changed as appropriate. The inkjet printer 1 according to the embodiment includes two carriages, a first carriage 10 that discharges white ink and a second carriage 20 that discharges color ink, and four inkjet heads 11 are provided on each carriage. Ink is discharged from -14, 21-24. However, even for an ink jet printer having one carriage having five ink jet heads, printing of the print data created by the print data creation device is executed based on the image data created by the image data creation device according to the present invention. It is possible to make it. Further, an inkjet printer that does not use black (K) ink may be used.

1 is a plan view of an inkjet printer 1. FIG. 1 is a block diagram showing an electrical configuration of an inkjet printer 1. FIG. 2 is a block diagram showing an electrical configuration of a personal computer 100. FIG. 2 is a schematic diagram showing a configuration of a RAM 112. FIG. 2 is a schematic diagram illustrating a configuration of an HDD. FIG. 4 is a flowchart of image data creation processing performed by the personal computer 100. 4 is a flowchart of print data creation processing performed by the personal computer 100. 5 is an explanatory diagram illustrating a relationship between an original image 182 and a printable area 181 and a background area 183. FIG. It is explanatory drawing of the image 185 corresponding to original image paste data.

1 Inkjet printer 100 Personal computer 110 CPU
111 ROM
112 RAM
116 HDD

Claims (7)

An image forming apparatus that outputs image data that is a basis for print data creation to a print data creation apparatus that creates the print data,
Original image data input means for inputting original image data which is image data of the original image;
Among the image representation colors that are used to represent the image, the unused color that is the image representation color that is not used for the pixels constituting the original image data input by the original image data input means An unused color identifying means for identifying
When the unused color is specified by the unused color specifying means, the unused color is used for pixels constituting a background area which is an area other than the area where the original image is arranged in the printable area. First background color setting means for setting as a background color to be
The specific image representation color of the pixel represented by the specific image representation color used for the pixel constituting the original image data when the unused color is not identified by the unused color identification means A color changing means for changing the color to another image expression color,
Second background color setting means for setting, as the background color, the specific image expression color that has become the unused color by the color change by the color changing means;
Wherein the background color set by the first background color setting means or the second background color setting means, use the pixels constituting the background area, placing the original image in the print area Image data creating means for creating image data of the obtained image;
Image data output means for outputting the image data created by the image data creation means to the print data creation device;
An image forming apparatus comprising: a background color storage unit that stores the background color in a background color storage unit that can be referred to by the print data generation apparatus. The color changing unit changes the specific image expression color to the other image expression color by changing a gradation value of any one of the color components constituting the specific image expression color. The image forming apparatus according to claim 1 . The other image representations color image forming apparatus according to claim 1 or 2, wherein the specific image representations color is an image display color being used next to the pixel of the pixel position. The unused color specifying means includes
For each of the image expression colors, a counting means for counting the number of times of use, which is the number of times used for the pixels constituting the original image data,
Determining means for determining whether or not there is the image expression color whose use count counted by the counting means is zero;
And a specifying unit that specifies the image expression color with the zero use count as the unused color when the determination unit determines that there is the image expression color with the use count of zero. the image forming apparatus according to any one of claims 1 to 3, characterized. The image forming apparatus according to claim 4 , wherein the specific image expression color is an image expression color that is least used and counted by the counting unit.   An image forming program used in an image forming apparatus that outputs image data that is a basis for creating print data to a print data creating apparatus that creates the print data,
  An original image data input step for inputting original image data which is image data of the original image;
  Among image representation colors that are used for representing an image, unused colors that are not used for the pixels constituting the original image data input in the original image data input step An unused color identification step to identify
  When the unused color is specified in the unused color specifying step, the unused color is used for pixels constituting a background area which is an area other than the area where the original image is arranged in the printable area. A first background color setting step for setting as a background color to be performed;
  In the unused color specifying step, when the unused color is not specified, the specific image expression color of the pixel expressed by the specific image expression color used for the pixel constituting the original image data A color change step for changing the color to another image expression color,
  A second background color setting step of setting, as the background color, the specific image expression color that has become the unused color by the color change in the color change step;
  Using the background color set in the first background color setting step or the second background color setting step for the pixels constituting the background region, the original image is arranged in the print region An image data creation step for creating image data of the image;
  An image data output step of outputting the image data created in the image data creation step to the print data creation device;
  A background color storing step of storing the background color in a background color storage means that can be referred to by the print data creation device;
An image forming program including an instruction for causing the controller of the image forming apparatus to execute.   A computer-readable recording medium storing an image forming program used in an image forming apparatus that outputs image data serving as a basis for creating print data to a print data creating apparatus that creates the print data,
  The image forming program includes:
  An original image data input step for inputting original image data which is image data of the original image;
  Among image representation colors that are used for representing an image, unused colors that are not used for the pixels constituting the original image data input in the original image data input step An unused color identification step to identify
  When the unused color is specified in the unused color specifying step, the unused color is used for pixels constituting a background area which is an area other than the area where the original image is arranged in the printable area. A first background color setting step for setting as a background color to be performed;
  In the unused color specifying step, when the unused color is not specified, the specific image expression color of the pixel expressed by the specific image expression color used for the pixel constituting the original image data A color change step for changing the color to another image expression color,
  A second background color setting step of setting, as the background color, the specific image expression color that has become the unused color by the color change in the color change step;
  Using the background color set in the first background color setting step or the second background color setting step for the pixels constituting the background region, the original image is arranged in the print region An image data creation step for creating image data of the image;
  An image data output step of outputting the image data created in the image data creation step to the print data creation device;
  A background color storing step of storing the background color in a background color storage means that can be referred to by the print data creation device;
Including a command for causing the controller of the image forming apparatus to execute the process.

Images