JP2010076317A - Printing device, printing method, and printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To print while satisfying both texture obtained by specific glossy ink and color reproducibility obtained by color ink. <P>SOLUTION: A CPU 40 for a printer 20 specifies, as main ink, one color ink that is large in amount used for printing a target image. When a dot for metallic ink is turned on, the CPU 40 continuously uses the same dither mask so as to prevent the dot for the main ink from being turned on, that is, so as to prevent overlapping of the dot for the metallic ink and the dot for the main ink. After performing a halftone process by a structural dither method, the CPU 40 carries out printing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing technique for performing printing using special glossy ink and color ink.

  Conventionally, a method is known in which an undercoat layer is first formed on a print medium, and printing is further performed on the undercoat layer (for example, Patent Document 1 below). Such a method can be used for various printing methods, for example, when reproducing metallic colors of various tones.

Special Table 2002-530229 JP-A-10-81026 JP-A-10-157167

  In order to reproduce the metallic color, for example, a metallic ink layer may be formed on a printing medium, and color ink may be superimposed on the layer to be printed.

  However, when such superposition printing is performed, there has been a problem that metallic feeling and saturation are lowered. Further, for example, when a pigment ink is used as a color ink, the transparency of the pigment ink is low, which causes a problem that the resulting metallic feeling is small. These problems are not limited to metallic inks that contain metallic pigments that exhibit a metallic luster, but various special types that exhibit a texture other than coloring, such as inks that contain pigments that exhibit a luster similar to pearl luster. This is a common problem when glossy ink is used.

  In light of the above-described problems, the problem to be solved by the present invention is to perform printing while achieving both the texture obtained with the special glossy ink and the color expression with the color ink.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A printing apparatus that performs printing using special glossy ink and color ink,
An input unit for inputting image data;
Based on the input image data, the special gloss at each position on the print medium while suppressing the superimposition of the special gloss dots formed by the special gloss ink and the color dots formed by the color ink. A dot formation determination unit for determining whether or not dots and color dots are formed;
A printing apparatus comprising: a printing unit that discharges the special gloss ink and the color ink onto the print medium based on the determination, and executes printing of the image data.

  The printing apparatus having such a configuration performs printing while suppressing superposition of special glossy dots and color dots. Therefore, it is possible to suppress a decrease in the saturation of the color dots due to the superposition of both dots and a decrease in the texture obtained by the special glossy dots. As a result, the texture obtained by the special gloss ink and the color expression by the color ink can be reduced. Printing can be carried out at the same time.

[Application Example 2] The printing apparatus according to Application Example 1, wherein the printing apparatus includes a plurality of color inks, and further includes a specifying unit that specifies a main ink from among the plurality of color inks. A printing apparatus that performs determination while suppressing overlapping of dots and main ink dots formed by main ink.

  The printing apparatus having such a configuration specifies a main ink from among a plurality of color inks, and performs printing while suppressing superposition of special glossy dots and main ink dots. Therefore, even when there are multiple color inks, the superimposition of the special glossy dots and the color dots is effectively suppressed, and printing is performed with both the texture obtained by the special glossy ink and the color expression by the color inks. It can be carried out.

[Application Example 3] Application Example 2 in which the specifying unit determines, among a plurality of color inks, an ink that has a relatively large amount of use in printing image data, and identifies an ink that has a large amount of use as the main ink. The printing apparatus as described.

  The printing apparatus having such a configuration specifies an ink that is used in a relatively large amount in printing image data as a main ink. Since ink with a relatively large amount of use has a great influence on the printed image, printing can be performed while efficiently balancing the texture obtained with the special glossy ink and the color expression with the color ink. In addition, since the printing apparatus identifies the main ink, the user of the printing apparatus can easily perform such printing.

Application Example 4 The printing apparatus according to Application Example 3, further including a reduction unit that reduces the image data to generate reduced image data, and the specifying unit uses a large amount based on the reduced image data. A printing apparatus for determining ink.

  Since the printing apparatus configured as described above determines ink that is used in large quantities based on the reduced image data, it is possible to efficiently and quickly perform processing relating to identification of main ink.

[Application Example 5] The printing apparatus according to any one of Application Example 2 to Application Example 4, further including a dividing unit that divides input image data into predetermined regions, and the specifying unit includes the divided predetermined regions A printing device that identifies the main ink for each.

  Since the printing apparatus having such a configuration specifies the main ink for each predetermined divided area, even if the tendency of the type of ink used in one image printing is uneven for each area, the special gloss ink can be used. It is possible to perform printing while making the texture and color expression by color ink compatible over the entire print image.

Application Example 6 The printing apparatus according to Application Example 5, wherein the dividing unit detects an object present in the input image data and divides an area for each object as the predetermined area.

  Since the printing apparatus having such a configuration specifies the main ink for each object, a single main ink is specified in one object. That is, one object is divided into a plurality of areas, different main inks are specified in each area, and dot formation determination with different characteristics is not made based on them. The print image quality does not deteriorate due to the occurrence of gradation discontinuity at the corresponding location.

Application Example 7 The printing apparatus according to Application Example 6, wherein the dividing unit detects an edge of the input image data and detects each area closed by the detected edge as an object.
Since the printing apparatus configured as described above detects the area closed by the edge as an object, the object can be reliably detected.

[Application Example 8] The printing apparatus according to any one of Application Example 2 to Application Example 7, wherein the dot formation determination unit performs systematic dithering on one of the special glossy dots and the main ink dots. The presence or absence of dot formation is determined by the method, and the presence or absence of dot formation is determined by the systematic dither method for the other of the special glossy dots and the main ink dots, except for the position where it is determined that one dot will be formed. The printing device to judge.

  The printing apparatus having such a configuration can determine whether or not a dot is formed so that the other dot is not formed at a position where one of the special glossy dot and the main ink dot is formed. Superimposition of dots and main ink dots can be prevented.

[Application Example 9] The printing apparatus according to any one of Application Example 2 to Application Example 7, wherein either one of the special glossy dots and the main ink dots is used with a predetermined dither mask. The presence or absence of dot formation is determined by a specific dither method, and a special dither mask and a dither mask in which the magnitude of each threshold value of the predetermined dither mask is replaced with respect to the other of the main ink dots are used for systematic dithering. Printing device that determines the presence or absence of dot formation by law.

  The printing apparatus having such a configuration determines the presence or absence of dot formation for the other of the special glossy dots and the main ink dots by using a dither mask in which the threshold value of the dither mask is changed. That is, since the priority order of the dot formation positions is reversed between the special glossy dot and the main ink dot, the overlapping of both dots can be prevented until the duty of the special glossy dot and the main ink dot reaches 100.

[Application Example 10] The printing apparatus according to any one of Application Example 2 to Application Example 7, wherein the dot formation determination unit performs systematic dithering on any one of the special glossy dots and the main ink dots. The dot formation is determined by the error diffusion method for the positions where it is determined that dots are formed by the systematic dither method for the other of the special glossy dots and the main ink dots. A printing apparatus that determines the presence or absence of dot formation by an error diffusion method after relatively increasing the threshold value used for the determination.

  Since the printing apparatus having such a configuration determines the presence or absence of dot formation by the error diffusion method after relatively increasing the threshold value of the error diffusion method for the position determined to form dots by the systematic dither method, At this position, it becomes difficult to form dots by the error diffusion method. Therefore, the superimposition of the special glossy dot and the main ink dot can be suppressed.

[Application Example 11] In the printing apparatus according to any one of Application Example 2 to Application Example 7, the specifying unit specifies two types of color inks as main inks, and the dot formation determination unit includes special glossy dots and 2 For the second dot selected from the first dot group consisting of two types of main ink dots respectively formed by the types of main inks, the presence or absence of dot formation is determined by a systematic dither method. For the third dot selected from the dot group, except for the position where it is determined that the second dot is to be formed, the presence / absence of dot formation is determined by the systematic dither method, and selected from the first dot group A printing apparatus that determines the presence or absence of dot formation by a systematic dither method using a dither mask in which the size of each threshold of a predetermined dither mask is changed for the fourth dot.

  The printing apparatus having such a configuration determines whether or not dots are formed by combining the methods of Application Example 8 and Application Example 9 with respect to the special glossy dots and the two types of main ink dots respectively formed by the two types of main inks. Since the determination is made, it is possible to prevent these three types of dots from overlapping each other. That is, even if two types of main ink are specified, the operational effects of any one of Application Examples 2 to 7 can be obtained.

[Application Example 12] The printing unit can form relatively large large dots and small small dots, and any one of Application Examples 1 to 11 in which special glossy dots and / or color dots are formed with small dots. The printing apparatus as described.

  Since the printing apparatus having such a configuration forms the special glossy dots and / or color dots with small dots, the effect of suppressing the superimposition of the special glossy dots and the color dots can be enhanced as compared with the case of forming with the large dots.

In addition to the configuration as the above-described printing apparatus, the present invention can also be realized as a printing method of Application Example 13 and a printed matter of Application Example 14.
Application Example 13 A printing method that performs printing using special gloss ink and color ink, and suppresses the overlap of special gloss dots formed by the special gloss ink and color dots formed by the color ink. A printing method in which printing is performed by discharging special glossy ink and color ink onto a printing medium.

Application Example 14 Printed matter printed using special gloss ink and color ink, and formed with dots and color ink formed with special gloss ink in at least a part of the print area on the print medium. Printed matter that is printed with mixed dots so that they do not overlap.

  Further, the present invention can be implemented as a computer program, a storage medium storing the program, and the like in addition to the above-described printing apparatus, printing method, and configuration as a printed matter.

A. Overview of printing equipment:
FIG. 1 is a schematic configuration diagram of a printer 20 as an embodiment of the present invention. As shown in the figure, the printer 20 includes a mechanism for transporting the print medium P by the paper feed motor 74, a mechanism for reciprocating the carriage 80 in the axial direction of the platen 75 by the carriage motor 70, and a print head mounted on the carriage 80. And a control unit 30 that controls the exchange of signals with the paper feed motor 74, the carriage motor 70, the print head 81, and the operation panel 93. .

  A mechanism for reciprocating the carriage 80 in the axial direction of the platen 75 is installed in parallel with the axis of the platen 75 and is driven endlessly between the slide shaft 73 slidably holding the carriage 80 and the carriage motor 70. A pulley 72 and the like for stretching the belt 71 are included.

  On the carriage 80, ink cartridges 82 to 85 for color ink respectively containing cyan ink C, magenta ink M, yellow ink Y, and black ink K are mounted as color inks. In addition, an ink cartridge 86 for metallic ink containing metallic ink S is mounted on the carriage 80. The print head 81 below the carriage 80 is formed with nozzle rows corresponding to the color inks and the metallic ink S described above. When these ink cartridges 82 to 86 are mounted on the carriage 80 from above, ink can be supplied from each cartridge to the print head 81.

  In the present embodiment, the term “color ink” includes black ink. In this embodiment, the dye ink that uses the ink discharged to the printing medium to permeate the ink absorption layer and develops color in the ink absorption layer is used. However, pigment ink may be used.

  In addition, the metallic ink is an ink in which a printed matter develops a metallic feeling. As such a metallic ink, for example, an oil-based ink composition containing a metal pigment, an organic solvent, and a resin can be used. In order to produce a visually metallic texture effectively, the above-mentioned metal pigment is preferably tabular grains, the major axis on the plane of the tabular grains is X, the minor axis is Y, When the thickness is Z, the 50% average particle diameter R50 of the equivalent circle diameter determined from the area of the XY plane of the tabular grains is 0.5 to 3 μm, and the condition of R50 / Z> 5 is satisfied. It is preferable. Such a metal pigment can be formed of, for example, aluminum or an aluminum alloy, or can be formed by crushing a metal vapor-deposited film. The concentration of the metal pigment contained in the metallic ink can be set to 0.1 to 10.0% by weight, for example. Of course, the metallic ink is not limited to such a composition, and any other composition can be adopted as long as it is a composition that produces a metallic feeling.

  In this example, the composition of the metallic ink S is 1.5% by weight of an aluminum pigment, 20% by weight of glycerin, 40% by weight of triethylene glycol monobutyl ether, and 0.1% by weight of BYK-UV3500 (manufactured by Big Chemie Japan Co., Ltd.). It was.

  The control unit 30 includes a CPU 40, a ROM 51, a RAM 52, and an EEPROM 60 that are connected to each other via a bus. The control unit 30 develops a program stored in the ROM 51 or the EEPROM 60 in the RAM 52 and executes it as an input unit 41, a dot formation determination unit 42, a printing unit 43, a specifying unit 44, a reduction unit 45, and a division unit 46. Function. Details of these functional units will be described later. The EEPROM 60 stores a lookup table (LUT) 62 for converting RGB gradation values into CMYK gradation values.

  A memory card slot 91 is connected to the control unit 30, and image data ORG can be read and input from the memory card MC inserted into the memory card slot 91. In this embodiment, the image data ORG input from the memory card MC is data composed of three color components of red (R), green (G), and blue (B).

  The control unit 30 receives an instruction from the user via the operation panel 93 or the like, and an area (hereinafter referred to as “R”, “G”, “B”) for an arbitrary area in the input image data ORG. In addition to “color area”, an area composed of a metallic color (hereinafter referred to as “metallic area”) can be designated. The metallic area and the color area may be overlapped (the overlapping area is referred to as “metallic color area”). That is, each area may be designated so that printing in which dots formed by color ink and dots formed by metallic ink are mixed is performed in the same area.

  The printer 20 having the above hardware configuration drives the carriage motor 70 to reciprocate the print head 81 with respect to the print medium P in the main scanning direction, and also drives the paper feed motor 74. Thus, the print medium P is moved in the sub-scanning direction. The control unit 30 performs printing by driving the nozzles at an appropriate timing based on the print data in accordance with the movement of the carriage 80 in the reciprocating motion (main scanning) and the paper feeding movement of the printing medium (sub scanning). Ink dots of appropriate colors are formed at appropriate positions on the medium P. Thus, the printer 20 can print the color image input from the memory card MC on the print medium P.

B. Printing process:
A printing process in the printer 20 will be described. FIG. 2 is a flowchart of the printing process in this embodiment. The printing process is a process for performing metallic color printing, and is started when the user performs a print instruction operation for a predetermined image stored in the memory card MC using the operation panel 93 or the like. In this embodiment, the user designates a metallic area for the print target image together with the print instruction operation. When the printing process is started, the CPU 40 first performs a main ink specifying process as a process of the specifying unit 44 (step S110). This process will be described in detail with reference to FIG. As shown in the figure, when the main ink specifying process is started, the CPU 40 first reads and inputs RGB format image data ORG to be printed from the memory card MC via the memory card slot 91 (step S111). .

  When the image data ORG is input, the CPU 40 reduces the input image data ORG to a predetermined size and generates reduced image data RORG as a process of the reduction unit 45 (step S112). In this embodiment, the reduced image data RORG having a size that is 1/16 of the image data ORG is generated by the nearest neighbor method. However, the reduction method and the reduction size are not particularly limited.

  When the reduced image data RORG in the RGB format is generated, the CPU 40, according to the LUT 62 stored in the EEPROM 60, for cyan (C) and magenta (M) that are color components that can be expressed by the printer 20 for the color area in the reduced image data RORG. ), And converted into CMYK format image data in yellow (Y) and black (K) (step S115).

  When color conversion is performed, the CPU 40 determines, based on the converted image data, the type of ink that uses the largest amount of ink for printing the image data ORG, and identifies the type of ink as the main ink. (Step S116). In this embodiment, the main ink is specified using the reduced image data RORG generated in step S112. This is because the main ink can be identified efficiently and quickly. However, the reduction process of the image data ORG is not essential, and the main ink may be specified directly from the image data ORG. In this way, the accuracy of identifying the main ink is improved.

  The main ink specifying method is such that, for the reduced image data RORG, the total value of gradation values of each pixel is calculated for each color of CMYK, and the ink of the color having the largest total value is specified as the main ink. . In this way, it is possible to easily identify the main ink that has the largest amount of ink usage and has a large influence on the printed image. However, the configuration for specifying the main ink is not limited to this, and various configurations can be adopted. For example, the evaluation value may be calculated by multiplying the total value of the gradation values for each color by the weighting coefficient for each color, and the ink of the color having the largest evaluation value may be specified as the main ink. Specifically, for example, even if the weighting coefficients of cyan ink C, magenta ink M, and yellow ink Y, which are easily affected by saturation when superimposed on metallic ink S, are superimposed on metallic ink S, they are also affected by saturation. The evaluation value may be calculated by making it larger than the weighting coefficient of the black ink K which is difficult. Alternatively, halftone processing may be performed based on the converted image data, and based on the result, the type of ink having the largest ink usage may be specified as the main ink.

  When the main ink is specified, the CPU 40 stores the main ink type as main ink information in the RAM 52 (step S117), and returns the process to the printing process.

  When the main ink specifying process is completed, the CPU 40 inputs the image data ORG as the process of the input unit 41 (step S120). Then, the CPU 40 inputs the main ink information stored in step S117 (step S130).

  When the image data ORG and the main ink information are input, the CPU 40 performs color conversion from the RGB format to the CMYK format for the color area in the image data ORG as in step S115 (step S140).

  When the color conversion process is performed, the CPU 40 performs a halftone process that represents the degree of metallic feeling to be expressed by the distribution of dots for the metallic ink as a process of the dot formation determination unit 42 (step S150). Here, a well-known organized dither method is used. In this embodiment, when the user designates the metallic area, the degree of metallic feeling to be generated on the printed material is also input, and the CPU 40 has a duty corresponding to the inputted degree of metallic feeling. The halftone process was performed. However, the duty may be predetermined.

  When halftone processing is performed on the metallic ink, the CPU 40 selects one of the color inks (step S160), and determines whether or not the selected ink is the main ink specified in step S110 (step S170). ). As a result, if the selected ink is not the main ink (step S170: NO), the CPU 40 performs halftone processing in which the tone of the ink is expressed by the distribution of dots by a systematic dither method using a dither mask prepared in advance. (Step S200). In this embodiment, a dither mask having blue noise characteristics is used, and the dither mask is the same as the dither mask used in step S150 described above and step S180 described later.

  On the other hand, if the selected ink is the main ink specified in step S110 (step S170: YES), the CPU 40 performs halftone processing by continuously using the same dither mask as processing of the dot formation determination unit 42 (step S170: YES). Step S180). The halftone process here will be described in detail with reference to FIG. When this processing is started, the CPU 40 inputs the gradation value pixel data Dn (n represents a pixel position) of the image data ORG (step S181). When the pixel data is input, the CPU 40 determines whether or not the metallic ink dot at the pixel position n is determined to be ON in step S150 of the printing process (step S182).

As a result, if it is determined that the metallic ink dots are ON (step S182: YES), the CPU 40 determines that the main ink dots are OFF (step S186). On the other hand, if the dot of the metallic ink is determined to be OFF (step S182: NO), the CPU 40 adds the gradation value Vs of the metallic ink to the pixel data Dn, and the corrected pixel data RDn according to the following equation (1). Is calculated (step S183).
RDn = Dn + Vs (1)

  After calculating the corrected pixel data RDn, the CPU 40 determines whether or not the corrected pixel data RDn is greater than or equal to the dither mask threshold THn corresponding to the pixel position n (step S184). As a result, if the corrected pixel data RDn is equal to or greater than the threshold value THn (step S184: YES), the CPU 40 determines that the main ink dot at the pixel position n is ON (step S185). On the other hand, if the corrected pixel data RDn is less than the threshold value THn (step S184: NO), the CPU 40 advances the process to step S186. Thus, when the ON / OFF of the main ink dot is determined, the CPU 40 returns the process to the printing process.

  In such a halftone process, the dot of the main ink is turned OFF at the position where the metallic ink dot is turned ON, and the ON / OFF of the main ink dot is determined except for the position. Ink dots do not overlap. In the above-described example, the main color ink is determined in step S183 by determining ON / OFF of the main ink dot based on the corrected pixel data RDn obtained by adding the gradation value Vs of the metallic ink to the pixel data Dn. It is possible to accurately determine the occurrence of dots.

  In FIG. 2, ON / OFF of metallic ink dots is determined first, and ON / OFF of main ink dots is determined avoiding the positions of metallic ink dots ON. The order of determining / OFF is not particularly limited, and ON / OFF of the main ink dots is determined first, and ON / OFF of the metallic ink dots is determined avoiding the positions of the main ink dots ON. It is good also as a structure.

  Here, the description returns to FIG. When the halftone process is performed, the CPU 40 determines whether or not the processing in steps S160 to S200 has been completed for all ink types (step S210), and if there is an ink type for which processing has not been completed. (Step S210: NO), the process is returned to Step S160, and the processes of Steps S160 to S200 are performed for the unprocessed ink type. Although not particularly illustrated, in the present embodiment, the processes in steps S150 to S210 (also referred to as step SST) are repeated for each pixel, but may be repeated for each predetermined region. Alternatively, the entire image may be used as a unit.

  On the other hand, if the processing has been completed for all ink types (step S210: YES), the CPU 40 performs processing by the printing unit 43 based on the halftone processed print data, the carriage motor 70, the motor 74, and printing. The head 81 and the like are driven, and metallic ink and color ink are ejected from the print head 81 to execute metallic color printing (step S220). Thus, the printing process ends.

  The printer 20 having such a configuration specifies the main ink from among the color inks. In the metallic region, the presence or absence of the main ink and metallic ink dots is determined so that the dots formed by the main ink and the dots formed by the metallic ink do not overlap on the print medium. Printing is performed with such a dot arrangement. Therefore, in the printed matter in the metallic area, the dots formed by the metallic ink can sufficiently express the metallic feeling, and the dots formed by the main ink can sufficiently express the saturation, so that the metallic color can be expressed sufficiently. Printing can be performed while achieving both the metallic feel of ink and the color expression of color ink. Further, since the main ink is the ink having the largest amount of ink used for printing the image data ORG, that is, the ink having a large influence on the entire image, the above-described effects can be efficiently obtained. . This method is possible when the total duty of the metallic ink and the main ink is 100 or less. Needless to say, the present embodiment can be applied even when the printer 20 has a single color ink. Further, since the CPU 40 identifies the main ink, the user of the printer 20 can easily perform the above-described printing.

C. Variation:
A modification of the above embodiment will be described.
C-1. Modification 1:
In the embodiment, in the printing process shown in FIG. 2, halftone processing of each color is performed using the same dither mask in step S180 and step S200, but the dither mask used in steps S180 and S200 is as follows. Different ones may be used. By so doing, it is possible to suppress the overlapping of the metallic ink and the dots of the color ink other than the main ink, and the color expression by the color ink can be improved.

C-2. Modification 2:
The flow of the printing process as the modified example 2 is shown in FIGS. The difference from the embodiment shown in FIG. 3 and FIG. 4 is that image data ORG is divided into predetermined areas, and main ink is specified for each of the divided areas. Hereinafter, this point will be described in detail. 5 and 6, processes similar to those in the embodiment are denoted by the same reference numerals as in FIGS. 3 and 4, and the description is simplified. When starting the printing process as the second modification, the CPU 40 first performs a main ink specifying process (step S310).

  In this process, as shown in FIG. 6, the CPU 40 receives the image data ORG (step S111) and generates reduced image data RORG (step S112), as in the embodiment. Then, the CPU 40 divides the reduced image data RORG into a plurality of areas as processing of the dividing unit 46 (step S313). In this embodiment, the image data ORG is divided into 16 parts.

  When the reduced image data RORG is divided, the CPU 40 stores the coordinates of each divided region in the RAM 52 as divided region information (step S314), performs color conversion processing for each divided region, specifies the main ink, and then stores the main ink information. The data is stored in the RAM 52 (steps S315 to S317), and the process returns to the printing process. The processing of steps S315 to S317 is the same as steps S115 to S117 (see FIG. 3) in the embodiment except that the processing is performed for each divided region.

  When the main ink determination process is performed, the CPU 40 inputs the image data ORG (step S120), and further inputs the divided area information stored in step S314 and the main ink information stored in step S317 (step S317). S330).

  Then, the CPU 40 performs color conversion processing in the same manner as in the embodiment (step S140), and moves the divided areas (step S345). Here, one of the divided areas divided in step S313 is sequentially selected. In the present embodiment, the divided area selected first is the upper left area of the image data ORG. In the present embodiment, the input divided region information is coordinates in the reduced image data RORG. Therefore, by calculating the coordinates of the corresponding image data ORG based on this, the divided regions of the image data ORG can be obtained. Identified.

  When the divided area is moved, the CPU 40 executes the process shown in step SST of FIG. 2 for the moved divided area. That is, for the metallic ink and the main ink, halftone processing is performed by a systematic dither method by continuously using a dither mask so that dots are not overlapped. For color inks other than the main ink, a normal systematic dither method is used. Perform halftone processing.

  When the process of step SST is executed, the CPU 40 determines whether or not the process of step SST has been completed for all the divided areas of the image data ORG (step S355). As a result, if there is a divided area where the process has not been executed (step S355: NO), the CPU 40 returns the process to step S345 to move the divided area, and executes the process of step SST on the destination divided area. .

  On the other hand, if the process of step SST has been completed for all the divided regions (step S355: YES), the CPU 40 executes the printing of the image data ORG as in the embodiment (S220).

  The printer 20 having such a configuration divides the image data ORG into a plurality of divided areas, specifies the main ink for each divided area, and performs halftone processing so that the dots of the main ink and the metallic ink do not overlap. Therefore, even if the tendency of the type of ink used in the entire image data ORG is biased for each region, it is possible to prevent overlapping of ink and metallic ink dots that have a large influence on the image for each biased region. Therefore, the compatibility between the metallic feeling by the metallic ink and the color expression by the color ink can be realized over the entire printed image.

Further, the above-described divided area may be each area closed by the edge of the image data. For example, the luminance value Y of each pixel is calculated by the following equation (2) using the red, green, and blue gradation values R, G, and B in the input RGB format image data ORG, and a differential operator is used. A luminance edge may be detected, and an area closed by an edge having a strength equal to or greater than a predetermined value may be set as a divided area.
Y = 0.29891 × R + 0.58661 × G + 1.14848 × B (2)

  In this way, it is possible to reliably detect an object present in the image data and divide the area in units of the object. As a result, within one closed object, a single primary ink is identified and a single method of halftoning is performed, so multiple divided areas are assigned to one object, Different main inks are identified among the plurality of divided regions, and different halftone processes are not performed. Therefore, the print image quality does not deteriorate due to, for example, occurrence of gradation discontinuity at a location corresponding to the boundary of the divided area of the print image. Note that object detection is not limited to edge detection, and other methods may be used. For example, a region in a predetermined hue range may be detected, or may be detected by pattern matching of a predetermined shape.

C-3. Modification 3:
In the embodiment, the CPU 40 uses the same dither mask for the metallic ink and the main ink continuously, and performs halftone processing by a systematic dither method, thereby superimposing the dots of the metallic ink and the main ink. Although the configuration for suppressing the ink is described, the suppression of the overlapping of these inks is not limited to the method of the embodiment, and can be realized by various methods. For example, the halftone process shown in FIG. 7 may be performed instead of the halftone process in step S180 in the printing process of the embodiment. Hereinafter, the halftone process of FIG. 7 will be specifically described. In addition, about the process similar to FIG. 4, the code | symbol same as FIG. 4 is attached | subjected and description is simplified.

Specifically, the CPU 40 inputs the pixel data Dn of the image data ORG (Step S181). When the pixel data Dn is input, the CPU 40 calculates the corrected threshold value RTHn by correcting the threshold value THn at the position corresponding to the pixel position n in the dither mask used for the halftone process of the metallic ink in step S150 of FIG. (Step S481). Specifically, the correction threshold value RTHn is calculated by the following equation (3) using the threshold value THn and the maximum value THmax of the dither mask threshold value. For example, if the dither mask threshold is set from 0 to 255 and the THn threshold is 200, the correction threshold RTHn is 55 (= 255-200).
RTHn = THmax−THn (3)

  When the correction threshold value RTHn is calculated, the CPU 40 determines whether or not the pixel data Dn is greater than or equal to the correction threshold value RTHn (step S482). As a result, if the pixel data Dn is equal to or greater than the correction threshold value RTHn (step S482: YES), the main ink dot is determined to be ON (step S185), and if the pixel data Dn is less than the correction threshold value RTHn (step S482: NO), the dot of the main ink is determined to be OFF (step S186).

  That is, in the method of FIG. 7, the formation of the main ink dots is determined using a dither mask having thresholds whose magnitudes are interchanged with the threshold values of the dither mask used to determine the formation of metallic ink dots. It is. The dither mask configured with such a correction threshold value RTHn corresponds to a dither mask obtained by inverting the ease of dot formation with respect to the original dither mask. As a result, if it is considered that the same dither mask is used, dots are formed in the metallic ink in order from the portion with the smallest threshold, and dots are formed in the main ink in the order from the portion with the larger threshold. This method is hereinafter referred to as a reverse dither mask method.

  When the halftone process with such a configuration is performed, if the sum of the duties of the metallic ink and the main ink is 100 or less, the overlap of the dots of both inks can be prevented, and the sum of the duties exceeds 100. However, since the dots of both inks are overlapped only when the sum of the duties exceeds 100, the overlapping of the dots of both inks can be suppressed. Therefore, as in the embodiment, it is possible to improve the compatibility between the metallic feeling by the metallic ink and the color expression by the color ink. In addition, the configuration of the present modification can also be applied to printing in which the total duty of the metallic ink and the main ink exceeds 100.

C-4. Modification 4:
The configuration for suppressing the overlapping of the dots of the metallic ink and the main ink is not limited to the configuration using only the systematic dither method shown in the above-described embodiment, and various configurations are possible. For example, instead of the processing in step S180 in the printing processing of the embodiment, halftone processing may be performed by an error diffusion method as shown in FIG. Hereinafter, the halftone process of FIG. 8 will be described in detail. In addition, about the process similar to FIG. 4, the code | symbol same as FIG. 4 is attached | subjected and description is simplified.

  Specifically, the CPU 40 inputs the pixel data Dn of the image data ORG as in the third modification (step S181). When the pixel data is input, the CPU 40 determines whether or not the metallic ink dot is determined to be ON in step S150 (step S182). As a result, if the dot is determined to be ON (step S182: YES). ), A predetermined value β is added to the threshold value THn2 for determining whether or not dots are formed in the error diffusion method, and a relatively large correction threshold value RTHn2 is calculated (step S583).

  When the correction threshold value RTHn2 is calculated, the CPU 40 determines whether or not to form a dot of the main ink by the error diffusion method using the correction threshold value RTHn2 (step S584). In step S584, if the metallic ink dot is determined to be OFF (step S182: NO), the CPU 40 uses the threshold value THn2 to determine whether or not the main ink dot is formed by the error diffusion method. decide.

  In the printer 20 having such a configuration, whether or not dots are formed with metallic ink is determined by a systematic dither method, and whether or not dots are formed by main ink is determined by an error diffusion method. Further, when the metallic ink dots are determined to be ON, the threshold THn2 used in the error diffusion method is relatively increased and then the presence / absence of formation of the main ink dots is determined (steps S182 to S584). ). By adopting such a configuration, since the dots formed by the main ink are unlikely to be turned on at the locations where the dots formed by the metallic ink are turned on, the overlapping of both dots can be suppressed. As a result, it is possible to improve the compatibility between the metallic feeling of the metallic ink and the color expressibility of the color ink.

  In the above example, the main ink is configured to perform halftone processing by the error diffusion method, and the color ink other than the main ink is subjected to the halftone process by the systematic dither method. Tone processing may be performed. In this way, the main ink specifying process in step S110 can be omitted, and the process can be simplified. Further, the halftone processing method may be interchanged between the metallic ink and the main ink.

C-5. Modification 5:
In the above-described embodiment, the CPU 40 identifies one type of main ink and exemplifies a configuration that suppresses the overlap between the one type of main ink dot and the metallic ink dot. However, the main ink includes two types of main ink. Color ink may be used. For example, in the main ink specifying process in step S110, the CPU 40 uses the color ink (referred to as ink A) with the largest amount of ink used for printing the reduced image data RORG and the color ink (ink B) with the second largest amount. May be specified as the main ink.

  In such a case, the CPU 40 uses the same dither mask method shown in FIG. 4 for halftone for any two of the three types of ink A, ink B, and metallic ink S. Processing is performed, and the remaining one type of ink may be subjected to halftone processing by the method of using the reverse order of the dither mask shown in FIG. By so doing, it is possible to suppress the superposition of three types of ink.

  In the above-described continuous use of the dither mask, the ink (ink X) to which the dither mask is first applied, the ink to which the same dither mask is applied following the ink (ink Y), and the ink (ink that uses the dither mask in reverse order) The combination C (X, Y, Z) of Z) is (A, B, S), (A, S, B), (B, A, S), (B, S, A), (S, A , B) and (S, B, A) are considered, but considering that avoiding the overlapping of the metallic ink S and the ink A that uses the largest amount of ink as much as possible, (A, B, S) ), (A, S, B), (S, A, B), (S, B, A) are desirable.

C-6. Modification 6:
In the embodiment, in the main ink specifying process shown in FIG. 3, the CPU 40 specifies the type of ink that uses the largest amount of ink for printing the reduced image data RORG as the main ink. However, the present invention is not limited to such an ink, and may be a type of ink that is desired to avoid overlapping with dots formed by metallic ink, among a plurality of color inks. For example, the user inputs the type of ink whose saturation is most emphasized among the color inks installed in the printer 20 through the operation panel 93, and the CPU 40 receives the type and specifies the type of ink as the main ink. May be.

C-7. Modification 7:
When the printer 20 has a configuration capable of forming relatively large large dots and small small dots, dots formed by metallic ink and / or dots formed by main ink are formed by small dots. You may control as follows. In this way, even if ink bleeding or the like occurs, the overlapping of both dots can be reliably suppressed.

C-8. Modification 8:
In the above-described embodiment, the configuration in which metallic color printing is performed using metallic ink and color ink is exemplified, but the present invention is not limited to metallic color printing, and color ink and various special glossy inks are used. Can be applied to printing. A special gloss material is an ink that exhibits a special gloss on the surface of a print medium that has undergone printing. In addition to a metallic ink containing a pigment that expresses a metallic feeling, the optical properties of the ink printed on the surface of the print medium are reflected. The ink may have angle dependency and may have various appearances depending on the viewing angle. Specifically, as the ink, in addition to the metallic ink, a pearly ink containing a pigment that develops a pearly luster after fixing on the medium surface, a so-called lame sensation caused by irregular reflection after fixing on the medium surface. A laminar ink or a pigmented ink containing a pigment having fine irregularities so as to express a textured background can be used.

C-9. Modification 9:
In the above-described embodiment, the printer 20 is configured to execute all of the print processing of FIG. 2, but when a computer is connected to the printer 20, even if the computer executes a part of the print processing. Good. In such a case, the printing system constituted by the computer and the printer 20 can be regarded as a printing device in a broad sense.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. For example, the present invention can be applied to various printing apparatuses such as a laser printer that performs printing by adhering a special glossy toner and a color toner onto a printing medium in addition to an inkjet printer. In addition to the configuration as a printing apparatus, the present invention can be realized as a printing method, a printed matter, a program, a storage medium, and the like.

1 is a schematic configuration diagram of a printer 20 as an embodiment of the present invention. 3 is a flowchart illustrating a printing process procedure in the printer 20. It is a flowchart which shows the procedure of the main ink determination process in a printing process. It is a flowchart which shows the procedure of the process of step S180 in a printing process. It is a flowchart which shows the procedure of the printing process as a modification. It is a flowchart which shows the procedure of the main ink determination process in the printing process as a modification. It is a flowchart which shows the procedure of the process of step S180 in the printing process as a modification. It is a flowchart which shows the procedure of the process of step S180 in the printing process as a modification.

Explanation of symbols

20 ... Printer 30 ... Control unit 40 ... CPU
DESCRIPTION OF SYMBOLS 41 ... Input part 42 ... Dot formation judgment part 43 ... Printing part 44 ... Specific part 45 ... Reduction part 46 ... Dividing part 51 ... ROM
52 ... RAM
60 ... EEPROM
62 ... LUT
DESCRIPTION OF SYMBOLS 70 ... Carriage motor 71 ... Drive belt 72 ... Pulley 73 ... Sliding shaft 74 ... Paper feed motor 75 ... Platen 80 ... Carriage 81 ... Print head 82-86 ... Ink cartridge 91 ... Memory card slot 93 ... Operation panel P ... Printing medium MC ... Memory card

Claims (14)

A printing apparatus that performs printing using special glossy ink and color ink,
An input unit for inputting image data;
Based on the input image data, the special gloss at each position on the print medium while suppressing the superimposition of the special gloss dots formed by the special gloss ink and the color dots formed by the color ink. A dot formation determination unit for determining whether or not dots and color dots are formed;
A printing apparatus comprising: a printing unit that discharges the special gloss ink and the color ink onto the print medium based on the determination, and executes printing of the image data. The printing apparatus according to claim 1,
The color ink is plural,
Furthermore, a specific unit for specifying a main ink from the plurality of color inks is provided,
The dot formation determination unit is a printing apparatus that performs the determination while suppressing superimposition of the special glossy dot and a main ink dot formed by the main ink.   The determination unit determines an ink having a relatively large amount of use in printing the image data among the plurality of color inks, and identifies an ink having a large amount of use as the main ink. The printing apparatus as described. The printing apparatus according to claim 3,
Furthermore, a reduction unit that reduces the image data to generate reduced image data is provided,
The identification unit is a printing apparatus that performs determination of ink that increases the usage amount based on the reduced image data. The printing apparatus according to any one of claims 2 to 4,
Furthermore, the image processing apparatus includes a dividing unit that divides the input image data into predetermined areas.
The specifying unit specifies the main ink for each of the divided predetermined areas.   The printing apparatus according to claim 5, wherein the dividing unit detects an object existing in the input image data and divides an area for each object as the predetermined area.   The printing apparatus according to claim 6, wherein the dividing unit detects an edge of the input image data, and detects each area closed by the detected edge as the object. The printing apparatus according to any one of claims 2 to 7,
The dot formation determination unit
For any one of the special glossy dots and the main ink dots, the presence or absence of dot formation is determined by a systematic dither method,
A printing apparatus that determines the presence or absence of dot formation by a systematic dither method for the other dot of the special glossy dot and the main ink dot, except for the position where it is determined that the one dot is to be formed. The printing apparatus according to any one of claims 2 to 7,
For any one of the special glossy dots and the main ink dots, using a predetermined dither mask, determine the presence or absence of dot formation by a systematic dither method,
With respect to the other of the special glossy dots and the main ink dots, the presence or absence of dot formation is determined by a systematic dither method using a dither mask in which the threshold values of the predetermined dither mask are changed. Printing device. The printing apparatus according to any one of claims 2 to 7,
The dot formation determination unit
For any one of the special glossy dots and the main ink dots, determine the presence or absence of dot formation by a systematic dither method,
For the other dot of the special glossy dot and the main ink dot, the threshold used for the determination of dot formation by the error diffusion method is relative to the position where it is determined that the dot is formed by the systematic dither method. A printer that determines the presence or absence of dot formation using the error diffusion method. The printing apparatus according to any one of claims 2 to 7,
The specifying unit specifies two kinds of color inks as the main ink,
The dot formation determination unit
Whether or not dots are formed by a systematic dither method for the second dots selected from the first dot group consisting of the special glossy dots and the two types of main ink dots respectively formed by the two types of main inks. Judging
For the third dot selected from the first dot group, except for the position where it is determined that the second dot is to be formed, the presence or absence of dot formation is determined by a systematic dither method,
For the fourth dot selected from the first dot group, the presence or absence of dot formation is determined by a systematic dither method using a dither mask in which the threshold values of the predetermined dither mask are changed. apparatus.   The said printing part can form a comparatively large large dot and a small small dot, The said special glossy dot and / or the said color dot are formed in the said small dot. Printing device. A printing method that performs printing using special glossy ink and color ink,
Printing is performed by discharging the special glossy ink and the color ink onto the print medium while suppressing the overlap of the special glossy dot formed by the special glossy ink and the color dot formed by the color ink. Printing method. It is a printed matter printed using special gloss ink and color ink,
A printed matter in which dots formed by the special glossy ink and dots formed by the color ink are mixed so as not to overlap each other in at least a part of the printing area on the printing medium.

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