JP2009274294A - Liquid jet device and liquid jet method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the technique which can suppress the generation of strip banding and gloss banding. <P>SOLUTION: A printer 10 comprises a jet control section 372 which controls the jet amount of ink in a printed region formed by a black system or dark gray system color using a first mask pattern 610 gradually increasing from a jet ratio R1 to a jet ratio R2 from the edges of a duplicated region toward the center, and controls the jet amount of ink in a printed region formed by the other colors using a second mask pattern 620 gradually increasing from a jet ratio R3 to a jet ratio R4 from the edges of the duplicated region toward the center. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus that ejects liquid.

  A typical example of the liquid ejecting apparatus is an ink jet printer that ejects ink droplets onto a thin plate-like recording medium such as paper or plastic to record characters and figures. In addition, as a liquid ejecting apparatus, a liquid forming a color material, an electrode, or the like in a display manufacturing apparatus that manufactures a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, a surface emission display (FED), or the like In some cases, various shaped materials are injected into the pixel formation region and the electrode formation region.

  In a printing apparatus such as an ink jet printer, if the head unit is moved in the main scanning direction, ink is ejected from the head unit to form ink dots on the printing paper, and the printing paper is moved in the sub scanning direction. By alternately repeating the sub-scanning process, the print image is continuously formed in the sub-scanning direction of the printing paper. In the printed image formed in this way, due to printer operation errors such as paper feed error and left / right skew difference, the printed images are overly or underexposed, resulting in color shading. In some cases, light and dark streaks occur at the joints of the formed printed images. In the present specification, such light and dark stripes are referred to as “striping”. In Patent Document 1 below, in order to suppress stripe banding, the ink ejection ratio is gradually reduced toward the end in the sub-scanning direction in the overlap region where the print images formed by the front and rear main scans overlap. A technique for forming ink dots is disclosed.

JP 2006-281574 A

  However, although the conventional technique can suppress the stripe banding, the surface condition in the printed image is caused by the difference in the color overlapping order of the ink, the difference in the drying time of the ink, the overlapping state of the ink dots, and the like. In some cases, it becomes non-uniform, and a difference in gloss may occur at the joint between printed images formed by the main scanning before and after. In the present specification, such a gloss difference is referred to as “gloss banding”.

  In view of the above-described problems, an object of the present invention is to provide a technique capable of suppressing the occurrence of gloss banding as well as stripe banding.

  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 The liquid ejecting apparatus according to Application Example 1 is a liquid ejecting apparatus that ejects liquid onto an ejection target, and includes a head unit having a nozzle row in which a plurality of nozzles that eject the liquid are arranged, and the head A main scanning unit that performs a main scanning to move the unit in a main scanning direction intersecting the nozzle row relative to the ejection target; and after the main scanning by the main scanning unit, the ejection target is moved to the head Using a sub-scanning unit that performs sub-scanning that moves in a sub-scanning direction substantially along the nozzle row relative to the unit, and a mask pattern in which the liquid ejection ratio is set in synchronization with the main scanning And an ejection control unit that controls the ejection amount of the liquid ejected from the plurality of nozzles, and the mask pattern is an overlapping region that overlaps the preceding and following main scans among the ejection regions ejected in one main scan In The first mask pattern that gradually increases from the first injection ratio to the second injection ratio as it goes from the end in the sub-scanning direction to the center in the injection region, and the sub-scan in the injection region in the overlapping region A mask pattern that gradually increases from the third injection ratio to the fourth injection ratio from the end of the direction toward the center, wherein the difference between the third injection ratio and the fourth injection ratio is the first injection ratio. A second mask pattern that is larger than a difference between the ratio and the second ejection ratio, and the ejection control unit has a predetermined color in an ejection area formed by the liquid ejected onto the ejection object. The first ejection control unit that controls the ejection amount of the liquid in the formed first region by using the first mask pattern, and a color different from the predetermined color in the ejection region. Liquid in the second region And a second ejection control unit that controls a body ejection amount using the second mask pattern. According to the liquid ejecting apparatus of the first application example, the gloss banding is relatively suppressed while suppressing the stripe banding by gradually increasing the ejection ratio from the end in the sub-scanning direction toward the center in the overlapping region where the front and rear main scans overlap. For the first region formed with a predetermined color having characteristics that are likely to occur, a mask pattern in which the width of the injection ratio for gradually increasing the injection ratio is narrower than the second region formed with another color is used. Gloss banding can be suppressed by reducing the difference in the amount of liquid injected between the region with a high injection ratio and the region with a low injection ratio.

  Application Example 2 In the liquid ejecting apparatus of Application Example 1, the predetermined color in the first region may be a color having a relatively dark color density than the color in the second region. According to the liquid ejecting apparatus of the application example 2, it is possible to suppress the gloss banding in the ejection area formed with a relatively dark color in which gloss banding is relatively likely to occur.

  Application Example 3 The predetermined color in the first region may be a black color or a gray color. According to the liquid ejecting apparatus of the application example 3, it is possible to suppress the gloss banding in the ejection area formed with a black or gray color in which gloss banding is relatively easily generated.

  Application Example 4 In the liquid ejecting apparatus according to any one of Application Examples 1 to 3, the first mask pattern is directed from the end in the sub-scanning direction in the ejection region toward the center in the overlapping region. The second mask pattern gradually increases from the vicinity of 0% toward the center in the sub-scanning direction in the injection area in the overlapping area. The pattern may gradually increase to an injection ratio in the vicinity of 100%. According to the liquid ejecting apparatus of the application example 4, it is possible to suppress the stripe banding and the gloss banding with a good balance.

  Application Example 5 In the liquid ejecting apparatus according to any one of Application Examples 1 to 4, the first and second mask patterns have a constant ejection ratio that is a maximum value apart from the overlapping region. It may have a certain collective area. According to the fifth application example, since there is a collective region formed by one main scan separately from an overlap region formed by two or more main scans, rather than forming all of the ejection regions by overlap regions. The processing efficiency for forming the injection region can be improved.

  Application Example 6 In the liquid ejecting apparatus according to any one of Application Example 1 to Application Example 5, the first and second mask patterns may be formed by overlapping the overlapping region with the front and rear main scanning in the overlapping region. The injection ratio may be the maximum value. According to the application example 6, since the overlapping region can be completed by two main scans, the processing efficiency for forming the ejection region is improved as compared to completing the overlapping region by three or more main scans. be able to.

  Application Example 7 The liquid ejection method of Application Example 7 is a liquid ejection method that ejects liquid onto an ejection target using a control device, and a plurality of main scanning units of the control device eject the liquid. A step of performing a main scan for moving a head unit having a nozzle row in which nozzles are arranged in a main scanning direction intersecting the nozzle row relative to the ejection target; and a sub-scanning unit of a control device, After main scanning by the main scanning unit, a step of performing sub-scanning in which the ejection target is moved relative to the head unit in a sub-scanning direction substantially along the nozzle row, and ejection control means of the control device And an ejection control step of controlling the ejection amount of the liquid ejected from the plurality of nozzles using a mask pattern in which the ejection ratio of the liquid is set in synchronization with the main scanning, the liquid ejecting step comprising: , One time main In the overlapping region that overlaps the front and rear main scans in the injection region injected in the inspection, the first injection ratio gradually increases from the first injection ratio to the second injection ratio from the end in the sub-scanning direction toward the center in the injection region. A first ejection control step of controlling a liquid ejection amount in a first area formed in a predetermined color among ejection areas formed by the liquid ejected onto the ejection target using one mask pattern And a mask pattern that gradually increases from a third injection ratio to a fourth injection ratio in the overlapping area from the end in the sub-scanning direction toward the center in the injection area, wherein the third injection ratio and the A color different from the predetermined color in the ejection region using a second mask pattern in which a difference from the fourth ejection ratio is larger than a difference between the first ejection ratio and the second ejection ratio. Formed with And a second ejection control step for controlling a liquid ejection amount in the second region. According to the liquid ejecting method of the application example 7, in the overlapping region where the front and rear main scans overlap each other, the gloss banding is relatively suppressed while suppressing the stripe banding by gradually increasing the ejection ratio from the end in the sub-scanning direction toward the center. For the first region formed with a predetermined color having characteristics that are likely to occur, a mask pattern in which the width of the injection ratio for gradually increasing the injection ratio is narrower than the second region formed with another color is used. Gloss banding can be suppressed by reducing the difference in the amount of liquid injected between the region with a high injection ratio and the region with a low injection ratio. The control device may be configured as a part of the liquid ejecting apparatus or may be configured separately from the liquid ejecting apparatus.

  The form of the present invention is not limited to the liquid ejecting apparatus, and can be applied to other forms such as a method for controlling the liquid ejecting apparatus and a program for causing a computer to realize a function of controlling the liquid ejecting apparatus. . Further, the present invention is not limited to the above-described embodiments, and it is needless to say that the present invention can be implemented in various forms without departing from the spirit of the present invention.

  In order to further clarify the configuration and operation of the present invention described above, a liquid ejecting apparatus to which the present invention is applied will be described below. In the present embodiment, an ink jet printer typified by an image recording apparatus that is one form of the liquid ejecting apparatus will be described as an example.

A. Example:
A1. Printer configuration:
FIG. 1 is an explanatory diagram mainly showing the external configuration of the printer 10. The printer 10 is an ink jet printer that prints data such as characters and images by ejecting ink droplets onto a print medium 900 such as paper or a label. In this embodiment, the printer 10 has various functions such as a scanner and a copy as a so-called multifunction machine.

  The printer 10 includes a card slot 140 and a communication connector 150. The card slot 140 of the printer 10 is an interface that connects to a memory card 810 containing a storage medium such as a flash memory or a small hard disk so that data can be exchanged. The communication connector 150 of the printer 10 is an interface that connects to an external device 820 such as a personal computer, a digital still camera, or a digital video camera so as to exchange data. In this embodiment, the printer 10 is connected to the memory card 810 connected to the card slot 140 and the communication connector 150 in addition to the function of printing based on a print request from the external device 820 connected to the communication connector 150. It has a function of printing image data stored in the external device 820.

  The printer 10 further includes a scanner unit 130, a display 160, and an operation panel 170. The scanner unit 130 of the printer 10 reads a document placed on a document table and converts it into digital data (scan). The display 160 of the printer 10 displays characters and images for the user of the printer 10. The operation panel 170 of the printer 10 receives an instruction input from the user of the printer 10.

  FIG. 2 is an explanatory diagram mainly showing the internal configuration of the printer 10. In addition to the card slot 140 and the communication connector 150 described in FIG. 1, the printer 10 further includes a main control unit 110 that is a control device that controls each unit of the printer 10 and a printing mechanism that executes printing on the printing medium 900. Unit 120.

  As shown in FIG. 2, the printing mechanism unit 120 of the printer 10 includes a carriage 200, a head unit 210, a carriage drive unit 240, and a conveyance unit 250. The carriage driving unit 240 of the printing mechanism unit 120 drives the carriage 200 in the main scanning (head scanning) direction above the printing medium 900. The transport unit 250 of the printing mechanism unit 120 transports the print medium 900 in the sub-scanning direction that intersects the main scanning direction in which the carriage 200 moves.

  The carriage 200 of the printing mechanism unit 120 holds the head unit 210 and mounts the ink cartridge 220. The ink cartridge 220 mounted on the carriage 200 supplies ink to the head unit 210. In the present embodiment, the ink cartridge 220 contains eight colors of ink of photo black, gray, light gray, cyan, light cyan, magenta, light magenta, and yellow. In this embodiment, the photo black ink is a highly glossy pigment ink mainly used for photographic printing.

  The head unit 210 of the printing mechanism unit 120 includes an ejection head 212 for each type of ink stored in the ink cartridge 220. In this embodiment, the head unit 210 includes a total of eight ejection heads 212 for each color ink of photo black, gray, light gray, cyan, light cyan, magenta, light magenta, and yellow accommodated in the ink cartridge 220. . Printing on the print medium 900 is realized by the respective units of the ejection head 212, the carriage driving unit 240, and the transport unit 250 of the printing mechanism unit 120 based on instructions from the main control unit 110.

  FIG. 3 is an explanatory diagram schematically showing the arrangement configuration of the ejection head 212 in the head unit 210. The ejection head 212 has a nozzle row in which a plurality of nozzles 214 that eject ink supplied from the ink cartridge 220 are arranged in the sub-scanning direction. Injection and injection stop are controlled by adjusting the voltage of a piezo element (not shown) corresponding to each of the plurality of nozzles 214. In this embodiment, the nozzle 214 can form ejection dots with three types of sizes, large dots, medium dots, and small dots. In the present embodiment, each of the ejection heads 212 has 360 nozzles 214, and the nozzles 214 are arranged at an interval of 360 dpi (hereinafter referred to as “dpi”) in the sub-scanning direction. In FIG. 3, all of the plurality of nozzles 214 in the ejection head 212 are shown arranged in a row, but in another embodiment, the plurality of nozzles 214 may be arranged in a plurality of rows.

  Returning to the description of FIG. 2, the main control unit 110 of the printer 10 includes a print data acquisition unit 310 and a print control unit 370. In this embodiment, the main control unit 110 of the printer 10 includes a central processing unit (hereinafter referred to as CPU) 112, a read only memory (hereinafter referred to as ROM), and a random access memory (Random Access). Memory 114 (hereinafter referred to as “RAM”). In this embodiment, the functions of the print data acquisition unit 310 and the print control unit 370 in the main control unit 110 are realized by the CPU 112 operating based on software. However, as another embodiment, the main control unit 110 This electronic circuit may be realized by operating based on its physical circuit configuration.

  The print data acquisition unit 310 of the main control unit 110 acquires the print data 710 from the memory card 810 connected to the card slot 140 or the external device 820 connected to the communication connector 150. In this embodiment, the print data 710 acquired by the print data acquisition unit 310 is stored in the memory 114.

  The print control unit 370 of the main control unit 110 instructs the print mechanism unit 120 to print the print data 710. The print control unit 370 includes an ejection control unit 372, a main scanning unit 374, and a sub scanning unit 376. The main scanning unit 374 of the print control unit 370 controls main scanning that moves the head unit 210 in the main scanning direction relative to the print medium 900. The sub-scanning unit 376 of the print control unit 370 controls sub-scanning that moves the print medium 900 relative to the head unit 210 in the sub-scanning direction after the main scanning by the main scanning unit 374.

  The ejection control unit 372 of the print control unit 370 uses a first mask pattern 610 and a second mask pattern 620 in which the ink ejection ratio is set in synchronization with the main scanning by the main scanning unit 374, and uses a plurality of nozzles. The ejection amount of ink ejected from 214 is controlled. In the present embodiment, the first mask pattern 610 and the second mask pattern 620 are stored in the memory 114 in advance. The ejection control unit 372 sets the ejection amount of the ink in the first color region formed with a black or dark gray color among the print regions that are ejection regions formed by the ink ejected onto the print medium 900. Control is performed using the first mask pattern 610. The ejection control unit 372 sets the ejection amount of ink in the second color area formed in a color area different from the first color area in the print area, that is, in a color different from the black and dark gray colors. Control is performed using the second mask pattern 620. In this embodiment, the black or dark gray color in the first color region formed by using the first mask pattern 610 is the usage ratio of photo black in the ink necessary to reproduce the color. Is a color with a relatively high color density such as (0: 0: 0), (10:10:10), (20:20:20), for example. The proper use of the first mask pattern 610 and the second mask pattern 620 is determined based on the average color density in the print area. In this embodiment, the average usage ratio of photo black in the print area is 40. The first mask pattern 610 is used for color areas exceeding%.

  FIG. 4 is an explanatory diagram schematically showing the first mask pattern 610. The first mask pattern 610 extends from the end in the sub-scanning direction toward the center of the ejection region in the overlapping region overlapping the main scanning before and after the main scanning (pass) in the ejection region where ink is ejected. It gradually increases from the first injection ratio R1 to the second injection ratio R2. In this embodiment, the first injection ratio R1 is an injection ratio in the vicinity of 10% including 5% to 15%, and the second injection ratio R2 is an injection ratio in the vicinity of 90% including 85% to 95%. It is. The first mask pattern 610 has an ejection ratio of 100%, which is the maximum value, by overlapping the overlapping area with the overlapping areas in the preceding and following passes. In the example shown in FIG. 4, in the ejection area formed in the first pass, a print dot raster is formed overlapping the subsequent sixth pass, the second pass is the seventh pass, and the third pass. The 8th pass, the 4th pass overlap the 8th pass, and the 5th pass overlaps the 10th pass. The first mask pattern 610 has a collective region where the injection ratio is constant at the maximum value of 100%. In the present specification, the ejection ratio means a ratio of pixels to be recorded in one main scanning among pixels included in a raster which is a pixel row arranged in one main scanning direction. Whether or not to actually record is determined based on the print data. For example, if the injection ratio is 50% in the solid area where all the pixels are recorded, 50% of the pixels included in the raster are included. Recording is performed in one main scanning, and the remaining 50% of pixels are recorded in the subsequent main scanning. In this embodiment, it is a mask pattern that determines whether or not to be recorded on a pixel-by-pixel basis, and the pattern of pixels to be recorded and pixels that are not to be recorded is preferably a dispersedly arranged pattern. A pattern in which pixels are periodically arranged every predetermined pixel in the main scanning direction may be used, or a pattern in which these pixels are irregularly arranged may be used. In another embodiment, instead of a mask pattern that determines whether or not to record on a pixel-by-pixel basis, the liquid ejection amount to be recorded in one pixel is recorded in one pixel that is recorded in one main scan. It may be a mask pattern that determines the ratio of the liquid ejection amount.

  FIG. 5 is an explanatory diagram schematically showing the second mask pattern 620. The second mask pattern 620 is located in the overlapping area overlapping with the preceding and following main scans in the ejection area where ink is ejected in one main scan (pass), from the end in the sub-scanning direction toward the center in the ejection area. It gradually increases from the third injection ratio R3 to the fourth injection ratio R4. The third injection ratio R3 in the second mask pattern 620 is smaller than the first injection ratio R1 in the first mask pattern 610, and the fourth injection ratio R4 in the second mask pattern 620 is the first injection ratio R4. It is larger than the second injection ratio R2 in the mask pattern 610. In the present embodiment, the third injection ratio R3 is an injection ratio in the vicinity of 0% including 0% to 4%, and the fourth injection ratio R4 is an injection ratio in the vicinity of 100% including 96% to 100%. It is. Similar to the first mask pattern 610, the second mask pattern 620 has an ejection ratio of 100%, which is the maximum value, by overlapping the overlapping area with the preceding and succeeding passes in the overlapping area. Similar to the first mask pattern 610, the second mask pattern 620 has a collective region in which the ejection ratio is constant at the maximum value of 100%.

A2. Comparison of Examples and Comparative Examples:
FIG. 6 is an explanatory diagram showing a comparison between Example 1 to Example 3 and Comparative Example 1 to Comparative Example 4. FIG. 7 is an explanatory diagram showing a comparison between Example 4 and Comparative Examples 5 and 6. In the examples and comparative examples in FIG. 6 and FIG. 7, under the respective printing conditions, “PX20000 (manufactured by Seiko Epson Corporation)” (the configuration of the head unit is the same as FIG. 3) for the printer, and photo black, Gray, light gray, cyan, light cyan, vivid magenta, vivid light magenta, yellow Each of the image quality evaluation colors was printed with a width of 44 inches (1118 millimeters), and gloss banding and stripe banding were visually determined under a fluorescent lamp. The five image quality evaluation colors are “Gray 1: RGB value (0, 0, 0)”, “Gray 2: RGB value (10, 10, 10)”, “Gray 3: RGB value (20, 20, 20). ”,“ Gray 4: RGB values (100, 100, 100) ”,“ Gray 5: RGB values (120, 120, 120) ”. In the example and comparative example shown in FIG. 6, the printing resolution was 720 × 720 dpi, the paper feed amount was (98 to 99) / 720 inch, and the number of overlapping nozzles was 148. In the example and comparative example shown in FIG. 7, the printing resolution was 1440 × 720 dpi, the paper feed amount was (64 to 65) / 720 inch, and the number of overlapping nozzles was 97.

  The evaluation criteria for gloss banding in the examples and comparative examples in FIGS. 6 and 7 are “evaluation value 5: no gloss banding is seen even when the angle is changed near”, “evaluation value 4:30 cm apart. Even if the angle is changed, the glossy banding is not visible ”,“ Evaluation value: 3-30 cm away and the angle is changed to see the glossy banding ”,“ Evaluation value: 2:30 cm away and the angle is changed to change the glossy banding “It stands out”, “If you change the angle 30 centimeters away, the gloss banding will stand out.”

  The evaluation criteria of the stripe banding in the examples and comparative examples in FIG. 6 and FIG. 7 are “evaluation value 5: no stripe banding can be seen at a close distance”, “evaluation value 4: 30 cm away and stripe banding can be seen. “No”, “Evaluation value: 3: 30 cm away, you can see streak banding”, “Evaluation value: 2: 30 cm away, streak banding is noticeable”, “30 cm away, streak banding is noticeable” .

  In the first embodiment, using the first mask pattern 610 in which the first injection ratio R1 is set to “5%” and the second injection ratio R2 is set to “95%”, gray 1 and gray 2 that are dark gray are used. , Gray 3, a second mask that controls the amount of ink ejected in the printing region formed by each color, and the third ejection ratio R3 is set to “0%” and the fourth ejection ratio R4 is set to “100%”. The pattern 620 was used to control the amount of ink ejected in the print area formed by the other colors, gray 4 and gray 5.

  In the second embodiment and the fourth embodiment, the first mask pattern 610 in which the first injection ratio R1 is set to “10%” and the second injection ratio R2 is set to “90%” is used. The ink ejection amount in the printing area formed by each color of 1, gray 2 and gray 3 was controlled, and the third ejection ratio R3 was set to “0%” and the fourth ejection ratio R4 was set to “100%”. The second mask pattern 620 was used to control the amount of ink ejected in the print area formed with the other colors, gray 4 and gray 5.

  In the third embodiment, using the first mask pattern 610 in which the first injection ratio R1 is set to “15%” and the second injection ratio R2 is set to “85%”, gray 1 and gray 2 that are dark gray are used. , Gray 3, a second mask that controls the amount of ink ejected in the printing region formed by each color, and the third ejection ratio R3 is set to “0%” and the fourth ejection ratio R4 is set to “100%”. The pattern 620 was used to control the amount of ink ejected in the print area formed by the other colors, gray 4 and gray 5.

  In Comparative Example 1 and Comparative Example 5, the second mask pattern 620 in which the third injection ratio R3 is set to “0%” and the fourth injection ratio R4 is set to “100%” is used in all print regions. The amount of ink ejected was controlled.

  In Comparative Example 2, the first mask pattern 610 in which the first ejection ratio R1 is set to “5%” and the second ejection ratio R2 is set to “95%” is used. Controlled.

  In Comparative Example 3 and Comparative Example 6, the first mask pattern 610 in which the first injection ratio R1 is set to “10%” and the second injection ratio R2 is set to “90%” is used in all print regions. The amount of ink ejected was controlled.

  In Comparative Example 4, the first mask pattern 610 in which the first ejection ratio R1 is set to “15%” and the second ejection ratio R2 is set to “85%” is used. Controlled.

  In Comparative Example 1 and Comparative Example 5 in which overlapping regions are formed with an ejection ratio of 0% to 100% for all printing regions, a relatively large gloss banding occurs in dark gray (gray 1, 2, 3). In Comparative Examples 2 to 4 and Comparative Example 6 in which overlapping regions were formed at an ejection ratio of 5% to 95%, 10% to 90%, and 15% to 85% for all printing regions, Comparative Examples 1 and 5 On the other hand, the improvement tendency is seen in suppression of the glossy banding in dark gray (gray 1, 2, 3). In particular, Comparative Example 3 and Comparative Example 6 in which overlapping regions are formed at an injection ratio of 10% to 90% have a higher improvement tendency in suppressing gloss banding than other comparative examples. For this reason, in order to improve the gloss banding, it is preferable to form an overlapping area at an injection ratio of 5% to 95%, 10% to 90%, 15% to 85%, and in particular, an overlapping area at an injection ratio of 10% to 90%. It turns out that it is good to form.

In Comparative Example 1 and Comparative Example 5 in which overlapping regions are formed with an ejection ratio of 0% to 100% for all printing regions, no occurrence of streaking is observed in all image quality evaluation colors. In Comparative Example 2 to Comparative Example 4 and Comparative Example 6 in which overlapping regions were formed with ejection ratios of 5% to 95%, 10% to 90%, and 15% to 85% for all inks, light gray (gray 4, 5) was used. The occurrence of stripe banding is observed. From this, it can be seen that it is better to form an overlapping region at an injection ratio of 0% to 100% in order to improve the stripe banding.

  In the first to fourth embodiments, the printing ratios of 5% to 95%, 10% to 90%, and 15% to 85% for the print areas formed by the dark gray, gray 1, gray 2, and gray 3 are used. Both the gloss banding and the stripe banding are improved by forming the overlapping area and forming the overlapping area at the injection ratio of 0% to 100% for the printing areas formed by the other colors, gray 4 and gray 5, which form the overlapping area. You can see that

A3. effect:
According to the printer 10 described above, relatively high gloss banding occurs while suppressing streaking by gradually increasing the ejection ratio from the end in the sub-scanning direction toward the center in the overlapping region where the front and rear main scans overlap. For a printing region formed with a black or gray color having a relatively dark color density and having an easy characteristic, the width of the ejection ratio for gradually increasing the ejection ratio is narrower than that of other liquids. Gloss banding can be suppressed by using the mask pattern 610 to reduce the difference in the ink ejection amount between the high ejection ratio area and the low ejection ratio area. In particular, when printing is performed using pigment ink, the color material floating without being dissolved in the solution of the pigment ink jetted onto the print medium 900 remains on the surface of the print medium 900. In some cases, the surface state of the printed image becomes non-uniform and the surface glossiness of the printed image changes due to the difference in the ink, the difference in the drying time of the ink, the degree of overlapping of the ink dots, and the like. According to the printer 10 in the present embodiment, it is possible to effectively suppress gloss banding in a printed image using pigment ink and other ink that easily generates gloss banding.

B. Other embodiments:
As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, it can implement with various forms within the range which does not deviate from the meaning of this invention. is there. For example, in the above-described embodiment, the overlapping region is formed at the ejection ratio of 5% to 95%, 10% to 90%, and 15% to 85% based on the first mask pattern 610. However, the first mask pattern The ejection ratio of 610 is not limited to these values, and can be appropriately set according to ink characteristics, head unit structure, recording medium characteristics, ink ejection method, and recording method. In the above-described embodiment, the overlapping region is formed with an injection ratio of 0% to 100% based on the second mask pattern 620. However, the injection ratio of the second mask pattern 620 is limited to these values. Instead, it can be set as appropriate according to the ink characteristics, the structure of the head unit, the characteristics of the recording medium, the ink ejection method, and the recording method. The relationship between the first mask pattern 610 and the second mask pattern 620 is that the difference between the third injection ratio R3 and the fourth injection ratio R4 in the second mask pattern 620 is the first mask pattern. What is necessary is just to be larger than the difference between the first injection ratio R1 and the second injection ratio R2 at 610. In this case, the third injection ratio R3 is smaller than the first injection ratio R1 (condition 1), and the fourth injection ratio R4 is larger than the second injection ratio R2 (condition 2). It is sufficient to satisfy at least one of the two conditions, and it is preferable to satisfy these two conditions at the same time.

  In the above-described embodiment, the ink ejection is controlled using the first mask pattern 610 in the print area formed with a color in which the usage ratio of the photo black exceeds 40%. However, the usage ratio of the photo black is The value is not limited to 40%, and can be set as appropriate according to the ink characteristics, the structure of the head unit, the characteristics of the recording medium, the ink ejection method, and the recording method. In the above-described embodiment, the color using the first mask pattern 610 is determined according to the usage ratio of photo black. However, the color is not limited to the usage ratio of photo black, and ink that easily generates gloss banding. For example, among the pigment inks, the color that uses the first mask pattern 610 according to the usage ratio of other inks such as inks that are particularly prone to gloss banding, inks having a relatively high color density, and black or gray inks. May be determined.

  In the above-described embodiment, the ink ejection is controlled by using the two mask patterns of the first mask pattern 610 and the second mask pattern 620. However, the mask pattern used for controlling the ink ejection is as follows. It is not limited to two, and can be set as appropriate according to ink characteristics, head unit structure, recording medium characteristics, ink ejection method, and recording method. For example, gloss banding and stripe banding for each color region A mask pattern in which a different ejection ratio is set for each color region may be prepared in accordance with the characteristics related to the above. In the above-described embodiment, the ink ejection is controlled by using the first mask pattern 610 only for the color region in which the usage ratio of the photo black exceeds 40%, but other color regions in which gloss banding is likely to occur. The first mask pattern 610 may be used (for example, in a color area where the usage ratio of light black or gray next to photo black is relatively high). In this case, a different ejection ratio is set for each color area. Two or more types of the first mask patterns 610 may be used. In the above-described embodiment, the single second mask pattern 620 is used in the other color areas except the color area where the usage ratio of the photo black exceeds 40%. Two or more set second mask patterns 620 may be used.

  In the present embodiment, the first mask pattern 610 and the second mask pattern 620 are mask patterns having an overlapping region and a collective region. However, the first mask pattern 610 and the second mask pattern 620 are composed of only overlapping regions in which the injection ratio gradually decreases and increases. It may be a mask pattern having no region. Further, the length of the overlapping region or the collective region in the nozzle row direction is not limited to the length of the present embodiment, but depends on the ink characteristics, the structure of the head unit, the characteristics of the recording medium, the ink ejection method, and the recording method. It can be set appropriately.

  Further, in the present embodiment, pixels recorded in other passes (second pass to fifth pass in the examples of FIGS. 4 and 5) are arranged between the pixels in the nozzle row direction printed in the first pass. The recording resolution in the nozzle row direction is higher than the nozzle density of the nozzle row, but in other embodiments, the recording resolution in the nozzle row direction is the same as the nozzle density of the nozzle row, and the first time The pass, the second pass, the second pass, and the third pass may overlap.

  The liquid targeted by the liquid ejecting apparatus of the present invention is not limited to the ink described above, but is intended to target various fluids such as metal paste, powder, and liquid crystal. As a typical example of the liquid ejecting apparatus, there is an ink jet recording apparatus provided with the ink jet recording head for image recording as described above. However, the present invention is not limited to the ink jet recording apparatus, and other methods are used. Electrode materials used to form electrodes for image recording devices, color material injection devices used in the manufacture of color filters such as liquid crystal displays, organic EL (Electro Luminescence) displays, and surface emission displays (Field Emission Displays, FEDs) The present invention can also be applied to an ejecting apparatus, a liquid ejecting apparatus that ejects a liquid containing a biological organic material used in biochip manufacturing, a sample ejecting apparatus as a precision pipette, and the like.

2 is an explanatory diagram mainly illustrating an external configuration of a printer. FIG. 2 is an explanatory diagram mainly showing an internal configuration of a printer. FIG. 4 is an explanatory diagram schematically showing an arrangement configuration of ejection heads 212 in a head unit 210. FIG. It is explanatory drawing which shows the 1st mask pattern 610 typically. It is explanatory drawing which shows the 2nd mask pattern 620 typically. It is explanatory drawing which shows contrast with Example 1 thru | or Example 3 and Comparative Example 1 thru | or Comparative Example 4. FIG. It is explanatory drawing which shows contrast with Example 4 and the comparative example 5 and the comparative example 6. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printer 110 ... Main control part 112 ... CPU
DESCRIPTION OF SYMBOLS 114 ... Memory 120 ... Printing mechanism part 130 ... Scanner part 140 ... Card slot 150 ... Communication connector 160 ... Display 170 ... Operation panel 200 ... Carriage 210 ... Head unit 212 ... Ejection head 214 ... Nozzle 220 ... Ink cartridge 240 ... Carriage drive part 250 ... Conveying section 310 ... Print data acquisition section 370 ... Print control section 372 ... Ejection control section 374 ... Main scanning section 376 ... Sub scanning section 610 ... First mask pattern 620 ... Second mask pattern 710 ... Print data 810 ... Memory card 820 ... External device 900 ... Print medium

Claims (7)

A liquid ejecting apparatus that ejects liquid onto an ejection target,
A head unit having a nozzle row in which a plurality of nozzles for ejecting the liquid are arranged;
A main scanning unit that performs main scanning for moving the head unit in a main scanning direction that intersects the nozzle row relative to the ejection target;
After the main scanning by the main scanning unit, a sub-scanning unit that performs sub-scanning that moves the ejection target in a sub-scanning direction substantially along the nozzle row relative to the head unit;
An ejection control unit that controls the ejection amount of the liquid ejected from the plurality of nozzles using a mask pattern in which the ejection ratio of the liquid is set in synchronization with the main scanning; and
The mask pattern is
In the overlapping region overlapping with the preceding and following main scans in the injection region injected in one main scan, the first injection ratio to the second injection ratio in the injection region from the end in the sub-scanning direction toward the center. A first mask pattern that gradually increases to
In the overlapping region, a mask pattern that gradually increases from a third injection ratio to a fourth injection ratio from the end in the sub-scanning direction toward the center in the injection region, the third injection ratio and the fourth A second mask pattern having a difference between the first injection ratio and the second injection ratio larger than the difference between the first injection ratio and the second injection ratio,
The injection control unit
A first ejection that controls the ejection amount of the liquid in the first area formed with a predetermined color among the ejection areas formed by the liquid ejected onto the ejection target using the first mask pattern. A control unit;
A liquid, comprising: a second ejection control unit that controls, using the second mask pattern, a liquid ejection amount in a second area formed in a color different from the predetermined color in the ejection area. Injection device.   The liquid ejecting apparatus according to claim 1, wherein the predetermined color in the first region is a color having a relatively dark color density than the color in the second region.   The liquid ejecting apparatus according to claim 1, wherein the predetermined color in the first region is a black color or a gray color. The liquid ejecting apparatus according to any one of claims 1 to 3,
The first mask pattern is a pattern that gradually increases from a vicinity of 10% to an injection ratio of about 90% toward the center from the end in the sub-scanning direction in the injection area in the overlapping area,
The liquid ejecting apparatus, wherein the second mask pattern is a pattern that gradually increases from a vicinity of 0% to a vicinity of 100% as the distance from the end in the sub-scanning direction toward the center in the ejection area in the overlapping area.   5. The liquid ejecting apparatus according to claim 1, wherein the first and second mask patterns have a collective region in which an ejection ratio is constant at a maximum value, apart from the overlapping region.   6. The liquid ejecting apparatus according to claim 1, wherein the first and second mask patterns have a maximum ejection ratio in the overlapping area when the overlapping area is overlapped with the overlapping area by front and rear main scanning. . A liquid ejecting method for ejecting liquid onto an ejected object using a control device,
A main scanning unit of the control device moves a head unit having a nozzle row in which a plurality of nozzles that eject the liquid are arranged in a main scanning direction that intersects the nozzle row relative to the ejection target. Scanning, and
A step in which the sub-scanning means of the control device performs sub-scanning after the main scanning by the main scanning unit to move the jetting object relative to the head unit in the sub-scanning direction substantially along the nozzle row. When,
An ejection control step in which an ejection control means of the control device controls an ejection amount of the liquid ejected from the plurality of nozzles using a mask pattern in which the liquid ejection ratio is set in synchronization with the main scanning. Prepared,
The liquid ejecting step includes
In the overlapping region overlapping with the preceding and following main scans in the injection region injected in one main scan, the first injection ratio to the second injection ratio in the injection region from the end in the sub-scanning direction toward the center. The first mask pattern that gradually increases to the first is used to control the liquid ejection amount in the first area formed in a predetermined color among the ejection areas formed by the liquid ejected onto the ejection target. An injection control process of
In the overlapping region, a mask pattern that gradually increases from a third injection ratio to a fourth injection ratio from the end in the sub-scanning direction toward the center in the injection region, the third injection ratio and the fourth The second injection pattern is formed in a color different from the predetermined color in the injection region using a second mask pattern in which a difference from the injection ratio is larger than a difference between the first injection ratio and the second injection ratio. A liquid ejection method comprising: a second ejection control step of controlling a liquid ejection amount in the second region to be performed.

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