Abstract:
Provided is a printing device which prints an image using a metallic ink and a color ink, the device including: an input unit which inputs image data; a metallic dot formation unit which forms dot concentration dots on a printing medium using the metallic ink; and a color print unit which prints the image indicated by the image data using the color ink on the printing medium on which the dots using the metallic ink are formed.

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a technology of printing an image using a metallic ink and a color ink. 
     2. Related Art 
     In an electrophotographic field, a technology of forming a solid layer using a metallic toner with respect to a region, in which a metallic color is specified, of image data and forming a process color toner layer thereon with high precision or sparsely is suggested (JP-A-2006-50347). In this technology, metallic colors of various color tones are reproduced by printing the process color toner so as to be superposed on the metallic toner. 
     However, for example, in an ink jet printer field, in the case where printing using the metallic ink is performed, if a pigment-based color ink is printed on a printing region formed by the metallic ink, glossy feeling deteriorates. In addition, if a dye-based color ink is printed on the metallic ink, the ink is hardly fixed and color development deteriorates. 
     SUMMARY 
     An advantage of some aspects of the invention is that color development of each color is improved when printing using a metallic ink and a color ink is performed. 
     The invention is to solve at least a portion of the above-described problems and can be realized as the following aspects. 
     According to an aspect of the invention, a printing device which prints an image using a metallic ink and a color ink, the device including: an input unit which inputs image data; a metallic dot formation unit which forms dot concentration dots on a printing medium using the metallic ink; and a color print unit which prints the image indicated by the image data using the color ink on the printing medium on which the dots using the metallic ink are formed. 
     According to this printing device, the dot concentration types dots (hereinafter, referred to as “metallic dots”) are formed on the printing medium by the metallic ink. Accordingly, the printing medium is exposed as the base between the metallic dots. As a result, although the image is printed using the color ink on the printing medium on which the metallic dots are formed, the dots using the color ink are formed in the base portion. Accordingly, according to the printing device in the above state, it is possible to suppress the color development of the color ink or the glossy feeling of the metallic color and suppress the deterioration of the scratch resistance of the color ink. 
     In the printing device, the metallic dot formation unit may print halftone dots as the dot concentration dots. By such a printing device, it is possible to form the metallic dots having a halftone dot shape. 
     In the printing device, the metallic dot formation unit may print dots having green noise characteristics as the dot concentration dots. By such a printing device, since the metallic dots having the green noise characteristics are formed on the printing medium, it is possible to suppress the generation of a periodical shape in the metallic region due to the mechanistic factor of the printing device or the generation of moiré due to a relationship with the color region. 
     In the printing device, the metallic dot formation unit may change the size of each of the dot concentration dots according to a predetermined condition. In such a printing device, it is possible to properly adjust the size of each of the metallic dots. 
     In the printing device, the metallic dot formation unit may change the size of each of the dot concentration dots according to the color tone of the color ink printed at position where the dots are formed. In such a printing device, it is possible to flexibly adjust the color development both the color ink and the metallic ink. 
     The printing device, the metallic dot formation unit may form the dot concentration dots at a predetermined gap therein. In such a printing device, although the gap is present in the metallic dots, the gap can be embedded by the dot gain of the metallic ink. Accordingly, it is possible to reduce the use amount of metallic ink and suppress the overflow or bleeding of the metallic ink. 
     In the printing device, the metallic dot formation unit may form the dot concentration type dots by ejecting ink droplets of the metallic ink on the printing medium. As such a printing device, for example, an ink jet printing device is applicable. 
     The invention may be embodied as a printing method or a computer program in addition to the above-described printing device. Such a computer program may be recorded in a computer-readable recording medium. As the recording medium, for example, various media such as a flexible disc, a CD-ROM, a DVD-ROM, a magnetooptical disc, a memory card, a hard disc or the like may be used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a view showing the schematic configuration of a printing system  10 . 
         FIG. 2  is a view showing the configuration of a computer  100 . 
         FIG. 3  is a view showing the configuration of a printer  200 . 
         FIG. 4  is a flowchart showing a printing process. 
         FIG. 5  is a view explaining a first example of a dot concentration type metallic dot. 
         FIG. 6  is a view explaining a second example of a dot concentration type metallic dot. 
         FIG. 7  is a view explaining a third example of a dot concentration type metallic dot. 
         FIG. 8  is a view explaining a fourth example of a dot concentration type metallic dot. 
         FIG. 9  is a view explaining a fifth example of a dot concentration type metallic dot. 
         FIG. 10  is a view explaining a sixth example of a dot concentration type metallic dot. 
         FIG. 11  is a view explaining a seventh example of a dot concentration type metallic dot. 
         FIG. 12  is a view explaining an eighth example of a dot concentration type metallic dot. 
         FIG. 13  is a view showing an example of forming dot dispersion type color dots on a metallic region. 
         FIG. 14  is a view showing an example of forming dot concentration type color dots on a metallic region. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the embodiments of the invention will be described in following order. 
     A. Outline of Embodiment: 
     B. Device Configuration: 
     C. Printing Process: 
     D. Examples of Dot Concentration Type Metallic Dot: 
     E. Printing Example of Color Ink: 
     A. OUTLINE OF EMBODIMENT 
       FIG. 1  is a block diagram showing the schematic configuration of a printing system  10  according to an embodiment of the invention. As shown, the printing system  10  according to the present embodiment includes a computer  100  as a print control device and a printer  200  for actually printing an image under the control of the computer  100 . The printing system  10  functions as a broadly-defined printing device, of which the whole is integrally formed. 
     In the printer  200  of the present embodiment, a cyan ink, a magenta ink, a yellow ink and a black ink are included as a color ink, and a glossy metallic ink is further included. As the metallic ink, for example, an ink composition containing a pigment, an organic solvent, a fixing resin, and, as a pigment, using a metal foil piece having an average thickness of 30 nm or more and 100 nm or less, a 50% volume-average particle diameter of 1.0 μm or more and 4.0 μm or less, and a maximum particle diameter in particle size distribution of 12 μm or less may be used. In the present embodiment, a “color ink” includes a black ink. 
     In the computer  100 , a predetermined operating system is installed, and an application program  20  is operated by this operating system. In the operating system, a video driver  22  or a printer driver  24  is assembled. The application program  20  inputs image data ORG from a digital camera  120 , for example, via a peripheral interface  108 . Then, the application program  20  displays an image displayed by the image data ORG on a display  114  via the video driver  22 . In addition, the application program  20  outputs the image data ORG to the printer  200  via the printer driver  24 . The image data ORG received from the digital camera  120  by the application program  20  is data including three color components of red (R), green (G) and blue (B). 
     The application program  20  of the present embodiment may specify a region having a metallic color (hereinafter, referred to as a “metallic region”) in addition to a region having color components of R, G and B (hereinafter, referred to as a “color region”), with respect to any region in the image data ORG. The metallic region and the color region may be superposed. That is, the respective regions may be specified such that the metallic color is used as a background color and the color image is formed thereon. 
     A color conversion module  42 , a halftone module  44  and a print control module  46  are included in the printer driver  24 . Among them, the print control module  46  includes a metallic dot formation module  47  and a color print module  48 . 
     The color conversion module  42  converts the color components R, G and B of the color region of the image data ORG into color components (cyan (C), magenta (M), yellow (Y) and black (K)) which can be represented by the printer  200 , according to a color conversion table LUT which is prepared in advance. 
     The halftone module  44  performs a halftone process of representing gradation of image data color-converted by the color conversion module  42  by a dot distribution. In the present embodiment, a known systematic dither method is used this halftone process. Alternatively, as the halftone process, in addition to the systematic dither method, an error diffusion method, a concentration pattern method or the other halftone techniques may be used. 
     The print control module  46  rearranges the data arrangement of the halftone-processed image data in transmission order to the printer  200  and outputs the data to the printer  200  as printing data. In addition, the print control module  46  outputs various commands such as a print start command or a print end command to the printer  200  so as to control the printer  200 . 
     In the present embodiment, the print control module  46  includes the metallic dot formation module  47  and the color print module  48 . The metallic dot formation module  47  forms a dot concentration type metallic dot in the metallic region specified by the application program  20 . Meanwhile, the color print module  48  performs the formation of the dots using the color ink, with respect to the halftone-processed image, that is, the image of the color region. 
     B. DEVICE CONFIGURATION 
       FIG. 2  is a view showing the configuration of the computer  100  as the print control device. The computer  100  is a known computer which is configured by connecting a CPU  102 , a ROM  104  or a RAM  106 , and so on by a bus  116 . 
     A disc controller  109  for reading data of a flexible disc  124 , a compact disc  126  or the like, a peripheral interface  108  for transmitting or receiving data to or from a peripheral, and a video interface  112  for driving the display  114  is connected to the computer  100 . The printer  200  or a hard disc  118  is connected to the peripheral interface  108 . When the digital camera  120  or a color scanner  122  is connected to the peripheral interface  108 , an image process may be performed with respect to an image captured by the digital camera  120  or the color scanner  122 . When a network interface card  110  is mounted, the computer  100  may be connected to a communication line  300  and data stored in a storage  310  connected to the communication line  300  may be acquired. When image data to be printed is acquired, the computer  100  controls the printer  200  by the operation of the above-described printer driver  24  such that the image data is printed. 
     Next, the configuration of the printer  200  will be described with reference to  FIG. 3 . As shown in  FIG. 3 , the printer  200  includes a mechanism for transporting printing medium P by a paper sheet motor  235 , a mechanism for reciprocally moving a carriage  240  by a carriage motor  230  in an axial direction of a platen  236 , a mechanism for driving a printing head  241  mounted in the carriage  240 , ejecting an ink, and forming dots, and a control circuit  260  for managing the signal transmission/reception of the paper feed motor  235 , the carriage motor  230 , the printing head  241  and an operation panel  256 . 
     The mechanism for reciprocally the carriage  240  in the axial direction of the platen  236  includes a sliding shaft  233  which is bridged in parallel to the shaft of the platen  236  and slidably holds the carriage  240 , a pulley  232  on which an endless driving belt  231  is stretched with the carriage motor  230 , a position detection sensor  234  for detecting an original point position of the carriage  240 , and so on. 
     In the carriage  240 , a color ink cartridge  243  containing a cyan ink (C), a magenta ink (M), a yellow ink (Y) and a black ink (K) as the color ink is mounted. In the carriage  240 , a metallic ink cartridge  242  containing a metallic ink (S) is mounted. In the printing head  241  located under the carriage  240 , a total of five types of ink ejection heads  244  to  248  corresponding to these colors are formed. If these ink cartridges  242  and  243  are mounted in the carriage  240  from the upper side, the supply of the inks from the cartridges to the ejection heads  244  to  248  is possible. 
     In the control circuit  260  of the printer  200 , the CPU, the ROM, the RAM, the PIF (peripheral interface) and so on are connected by the bus, and a main scanning operation and a sub scanning operation of the carriage  240  are controlled by controlling the operations of the carriage motor  230  and the paper feed motor  235 . When printing data output from the computer  100  is received via the PIF, driving signals according to the printing data are applied to the ink ejection heads  244  to  248  according to the main scanning or sub scanning movement of the carriage  240  such that these heads can be driven. 
     The printer  200  having the above-described hardware configuration reciprocally moves the ink ejection heads  244  to  247  of the respective colors with respect to the printing medium P in a main scanning direction by driving the carriage motor  230 , and moves the printing medium P in a sub scanning direction by driving the paper feed motor  235 . The control circuit  260  drives nozzles at appropriate timings based on the printing data according to the reciprocal movement (main scanning) of the carriage  240  or the paper feed movement (sub scanning) of a printing medium so as to form ink dots of appropriate colors at appropriate positions on the printing medium P. Accordingly, the printer  200  can print a color image on the printing medium P. 
     Although the printer  200  of the present embodiment is described as a so-called ink jet printer for ejecting ink droplets to the printing medium so as to form ink dots, a printer for forming dots using any method may be used. For example, instead of the ink droplets, the invention is suitably applicable to a printer for attaching toner powders of respective colors to a printing medium using static electricity so as to form dots or a line printer. 
     C. PRINTING PROCESS 
     Subsequently, a printing process executed by the computer  100  by the operation of the printer driver  24  will be described. 
       FIG. 4  is a flowchart showing a printing process according to the present embodiment. If the printing process is started, the computer  100  receives image data, in which the metallic region and the color region are specified, from the application program  20  by the printer driver  24  (step S 100 ). 
     When the image data is received, the computer  100  converts the image data of an RGB format into image data of a CMYK format, with respect to the color region of the image data (step S 102 ). When the image data of the CMYK format is obtained, the computer  100  performs a halftone process using the halftone module  44  and generates data which can be transmitted to the printer  200  (step S 104 ). 
     Subsequent to the halftone process, the computer  100  controls the printer  200  by the metallic dot formation module  47  and performs printing of the metallic region included in the image data received in the step S 100  (step S 106 ). At this time, the computer  100  forms a dot concentration type metallic dot in the metallic region such that a base portion (printing medium) in the metallic region is exposed. The detailed example of the dot concentration type metallic dot will be described in the below-described example. 
     When the printing of the metallic region is finished, lastly, the computer  100  controls the printer  200  by the color print module  48  and printing of the halftone-processed color region (step S 108 ). 
     The above-described printing system  10  according to the present embodiment performs the printing of the metallic region by the dot concentration type metallic dot such that the printing medium is exposed as the base prior to the printing of the color region, when the image data including the metallic region is printed. Accordingly, although the metallic region and the color region are superposed in the image, (at least a portion of) the dots of the color ink is formed in a portion in which the base of the metallic region are exposed. As a result, even when the metallic region and the color region are superposed, the damage of the color development of the color ink or the glossy feeling of the metallic color is suppressed. In addition, according to the present embodiment, since the dots of the color inks are formed on the base between the metallic dots, the scratch resistance of the color ink does not significantly deteriorate even when the metallic region and the color region are superposed. 
     D. EXAMPLES 
     Hereinafter, the detailed example of the metallic region printed by the dot concentration type metallic dot will be described. 
     (D1) First Example 
       FIG. 5  is a view explaining a first example of a dot concentration type metallic dot. Each of lattices of the drawing denotes a minimum size of a dot which can be formed on the printing medium by the printer  200 . A hatched portion shown in the drawing denotes a portion in which the dot is formed by the metallic ink. 
     As shown in  FIG. 5 , in the present example, the metallic region is formed such that rectangular halftone dots configured by concentrating a plurality of dots are connected in four directions at an angle 45°. In the example shown in  FIG. 5 , an example in which each halftone dot and the base portion between the halftone dots have the same area such that the metallic region having an average concentration of 50% is printed is shown. 
     (D2) Second Example 
       FIG. 6  is a view explaining a second example of a dot concentration type metallic dot. As shown in  FIG. 6 , in the present example, the metallic region is formed such that circular bases are arranged at an angle of 45°. In the metallic region shown in  FIG. 6 , since the metallic portion occupies a larger area than that of the base portion, the average concentration of the metallic region is 50% or more. 
     (D3) Third Example 
       FIG. 7  is a view explaining a third example of a dot concentration type metallic dot. As shown in  FIG. 7 , in the present example, the metallic region is formed such that circular halftone dots configured by concentrating a plurality of dots are arranged at an angle of 45°. In the metallic region shown in  FIG. 7 , since the base portion occupies a larger area than that of the metallic portion, the average concentration of the metallic region is 50% or less. 
     (D4) Fourth Example 
       FIG. 8  is a view explaining a fourth example of a dot concentration type metallic dot.  FIG. 8  shows an example in which the metallic region is formed such that circular halftone dots are arranged at a predetermined angle other than 45°. The dot concentration type halftone dots may be arranged at any angle, instead of 45°. 
     (D5) Fifth Example 
       FIG. 9  is a view explaining a fifth example of a dot concentration type metallic dot.  FIG. 9  shows an example in which the shape of the metallic dot is changed in the metallic region. Circular metallic dots are formed on the left side of the metallic region shown in  FIG. 9 , and rectangular metallic dots are formed on the central portion thereof. In addition, metallic portions are formed such that circular bases are exposed on the right side. That is, the metallic region is formed such that the concentration of the metallic color is increased from the left side to the right side. By changing the metallic concentration in the metallic region, portions having different glossy feelings can be formed in the same metallic region. 
     The metallic concentration in the metallic region can be, for example, adjusted according to the concentration of the color region which is printed so as to be superposed on the metallic region. That is, when the metallic region is printed in the step S 106  of the above-described printing process, the ink concentration of the color region superposed on the position where the metallic dots are formed is read from the halftone-processed image by the step S 104 , and this ink concentration and a predetermined condition are compared. For example, if the read concentration of the color ink is higher than the predetermined concentration, the metallic concentration of that portion is decreased and, if the concentration of the color ink is lower than the predetermined concentration, the metallic concentration of that portion is increased. By performing such a process, it is possible to improve the color development of both regions, even when the metallic region and the color region are superposed. 
     (D6) Sixth Example 
       FIG. 10  is a view explaining a sixth example of a dot concentration type metallic dot. In the example shown in  FIG. 10 , an example in which metallic dots having irregular shapes and a spatial frequency having green noise characteristics are formed in the metallic region is shown. Such metallic dots may be formed by using a dither matrix for outputting characteristics in which a high frequency component and a low frequency component are low and an intermediate frequency component is high. When the metallic dots having irregular shapes are formed, it is possible to suppress the generation of a periodical shape in the metallic region due to the mechanistic factor of the printer  200  or the generation of moiré due to a relationship with the halftone-processed color region. 
     (D7) Seventh Example 
       FIG. 11  is a view explaining a seventh example of a dot concentration type metallic dot. In the example shown in  FIG. 11 , a linear region is formed by a plurality of metallic dots and the linear region is continuously arranged in parallel such that a stripe-shaped metallic region is formed. In the example shown in  FIG. 11 , although the angle of the stripe is approximately 40°, the angle may be arbitrarily adjusted and the stripe may be formed in a vertical direction or a horizontal direction. In addition, a gap between the stripes may be arbitrarily adjusted. 
     (D8) Eighth Example 
       FIG. 12  is a view explaining an eighth example of a dot concentration type metallic dot. In the example shown in  FIG. 12 , rectangular halftone dots configured by concentrating a plurality of dots are connected in four directions at an angle of 45°, and the dots in the halftone dots are randomly thinned so as to form gaps. Although the dots in the halftone dots are thinned, when the metallic ink is actually ejected on the printing medium, the metallic ink is embedded in the thinned portions for a dot gain. By this configuration, it is possible to reduce the use amount of the metallic ink and suppress the overflow or bleeding of the ink. In addition, in either of the above-described examples, the dots may be thinned like the present example. The thinning of the dots may be, for example, realized by previously generating a mask obtained by subtracting dots having blue noise characteristics from a mask of the halftone dots and applying this mask to the metallic region. 
     E. PRINTING EXAMPLE OF COLOR INK 
       FIGS. 13 and 14  are views showing examples in which the image of the color region is printed on the metallic region shown in the first example ( FIG. 5 ) using the color ink.  FIG. 13  shows an example of forming the color region by dot dispersion type dots and  FIG. 14  shows an example of forming the color region by dot concentration type dots. As shown in these drawings, when the color region is formed by the dot dispersion type dots or the dot concentration type dots after the metallic region is formed by the dot concentration type metallic dots, a portion of the color dots is ejected on the metallic region, but the other portion thereof is ejected on the base portion exposed from the metallic region. Accordingly, even when the metallic region and the color region are superposed, it is possible to suppress the damage of the color development of the color ink or the glossy feeling of the metallic color and suppress the deterioration of the scratch resistance of the color ink. Such effects are the same even when the color ink is the pigment-based ink or the dye-based ink. 
     Although the color ink is allowed to be ejected on the metallic ink in the printing example shown in  FIGS. 13 and 14 , the control may be performed such that the color ink is ejected on only the base portion except the metallic ink portion. 
     Although the embodiment and the various examples of the invention are described, the invention is not limited to the embodiment and the examples and various configurations can be taken without departing from the range of the invention. 
     For example, in the above-described embodiment, in the printing system  10  including the computer  100  and the printer  200 , the printing using the metallic ink is performed. In contrast, the printer  200  may receive the image data from the digital camera or various types of memory cards and perform the printing using the metallic ink. That is, the CPU of the control circuit  260  of the printer  200  may perform the same process as the above-described printing process and perform the printing using the metallic ink. 
     The printing system  10  according to the above-described embodiment may select a metallic region to be formed according to any one of the above-described examples in a setup screen of the printer driver  24 . At this time, the concentration of the metallic ink may be allowed to be input such that the average concentration of the metallic region, that is, the size of the metallic dot, is set according to this concentration.