JP2013193239A - Liquid ejection apparatus and liquid ejection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent degradation of image quality of each image and reduce the time needed for recording when recording a white image and color images overlapping the white image on a recording medium by ejecting a white liquid and non-white liquids of multiple colors.SOLUTION: A liquid ejection apparatus includes a liquid ejection section which records an image on a recording medium by ejecting a white liquid and non-white liquids of multiple colors. The liquid ejection section performs a first recording operation that ejects the white liquid for recording a white image, and then performs a second recording operation that performs ejection of the non-white liquids for recording color images and ejection of the white liquid to regions of the white image except regions overlapping the color images, in parallel after the first recording operation.

Description

  The present invention relates to a liquid ejecting apparatus and a liquid ejecting method, and more particularly, to a liquid ejecting apparatus and a liquid ejecting method for recording an image on a recording medium by ejecting a white liquid and a plurality of non-white liquids.

  In addition to non-white inks (hereinafter referred to as “color inks”) such as cyan, magenta, yellow, and black, inkjet printers that record images by discharging white (white) ink are known (for example, Patent Document 1). An ink jet printer that discharges white ink and color ink, for example, records a white image by discharging white ink onto a transparent film or color paper (non-white paper) as a recording medium. A color image overlapping the white image can be recorded by ejecting color ink on the top.

JP 2009-279888 A

  In conventional inkjet printers, when recording a white image and a color image that overlaps the white image on a recording medium, there is room for improvement in terms of both the reduction in image quality of each image and the reduction in time required for recording. was there.

  Such a problem is not limited to the white ink and the color ink, but is a common problem when an image is recorded on a recording medium by discharging a white liquid and a plurality of non-white liquids.

  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 liquid ejecting apparatus including a liquid ejecting unit that ejects white liquid and a plurality of non-white liquids to record an image on a recording medium, and the liquid ejecting unit is disposed on the recording medium. When recording a white image and a color image overlapping the white image, a first recording operation for discharging the white liquid for recording the white image is performed, and after the first recording operation, Performing a second recording operation in which the discharge of the non-white liquid for recording the color image and the discharge of the white liquid to a region other than the region overlapping the color image in the white image are performed in parallel. Liquid ejection device. In this liquid ejection apparatus, in the second recording operation performed after the first recording operation for recording a white image, in addition to the recording of the color image, the region other than the region overlapping the color image in the white image ( Since the white liquid is discharged to the non-overlapping region, the amount of white liquid discharged per unit area in the non-overlapping region of the white image can be increased, and the deterioration of the image quality of the white image can be suppressed. Further, in this liquid ejecting apparatus, since a color image is also recorded in the second recording operation in which the white liquid is applied to the non-overlapping region, the time required for recording can be shortened.

[Application Example 2] In the liquid ejection apparatus according to Application Example 1, in the second recording operation, the region in which the white liquid is ejected has a maximum ejection amount of the liquid ejection unit from the color image. A liquid ejection apparatus that is separated by a liquid from a dot diameter formed on a recording medium by a liquid. In this liquid ejecting apparatus, it is possible to prevent the white liquid ejected to the non-overlapping region from being mixed with the non-white liquid ejected for recording the color image, and to reduce the image quality of the color image and the white image. Can be suppressed.

  The present invention can be realized in various forms, for example, in the form of a liquid ejection apparatus and a liquid ejection method, a printing apparatus and a printing method, a liquid ejection apparatus or a control method for the printing apparatus, and the like. Can do.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a printer 20 according to an embodiment of the present invention. It is explanatory drawing which shows the outline | summary of the image recording process in a present Example. It is explanatory drawing which shows the outline | summary of the image recording process in a present Example. It is explanatory drawing which shows the outline | summary of the image recording process in a present Example. It is explanatory drawing which shows the production | generation method of the recording data for implement | achieving the image recording process in a present Example.

A. Example:
A-1. Printer configuration:
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a printer 20 according to an embodiment of the present invention. The printer 20 in this embodiment is an ink jet printer that forms ink dots on the recording medium TF by ejecting ink from a plurality of nozzles 63, thereby printing (recording) an image on the recording medium TF. In this specification, “image” includes all images that can be formed by ink dots, including characters, symbols, line drawings, graphics, and photographic images.

  As shown in FIG. 1, the printer 20 includes a print head unit 60 on which a print head 61 is mounted, and a print head unit transport that performs main scanning for reciprocating the print head unit 60 along a direction parallel to the axis of the platen 52. A mechanism 40, a recording medium transport mechanism 50 that performs sub-scanning to transport the recording medium TF in a direction crossing the main scanning direction (sub-scanning direction), an operation panel 98 that receives various instruction / setting operations related to recording, and a printer And a control unit 30 for controlling the respective units.

  The recording medium transport mechanism 50 has a motor 51. The rotation of the motor 51 is transmitted to the transport roller (not shown) via a gear train (not shown), and the recording medium TF is transported on the platen 52 along the sub-scanning direction by the rotation of the transport roller. In this embodiment, a transparent film is used as the recording medium TF.

  The print head unit transport mechanism 40 is slidably held by a motor 41, a pulley 43 that stretches an endless drive belt 42 between the motor 41, and a platen 52 in parallel. Shaft 44. The rotation of the motor 41 is transmitted to the print head unit 60 via the drive belt 42, whereby the print head unit 60 reciprocates along the axial direction (main scanning direction) of the shaft 44. The main scanning direction is a direction substantially orthogonal to the sub-scanning direction.

  Five ink cartridges 70 (70a to 70e) are mounted on the holder 62 of the print head unit 60. Each ink cartridge 70 contains inks of different colors (cyan (C), magenta (M), yellow (Y), black (K), white (white, W)). The ink accommodated in each ink cartridge 70 mounted on the holder 62 is supplied to the print head 61. Ink other than white ink is collectively referred to as color ink.

  The print head 61 has five nozzle rows 65 corresponding to the five colors of ink. Each nozzle row 65 is composed of a plurality of nozzles 63 arranged at a predetermined nozzle pitch NP (for example, a pitch corresponding to 180 dpi) along the sub-scanning direction. The five nozzle rows 65 are arranged on one surface of the print head 61 (the surface facing the platen 52) along the main scanning direction. The plurality of nozzles 63 constituting each nozzle row 65 need not be arranged in a straight line, and may be arranged in a staggered pattern, for example.

  The print head 61 has a nozzle actuator (for example, a piezo element) (not shown) for ejecting ink from each nozzle 63. When the nozzle actuator is driven, the diaphragm in the cavity (pressure chamber) communicating with the nozzle 63 is displaced to cause a pressure change in the cavity, and ink is ejected from the corresponding nozzle 63 by the pressure change. The

  The control unit 30 includes a CPU 31 that executes various arithmetic processes, a RAM 37 that temporarily stores and expands programs and data, and an EEPROM 38 that stores programs executed by the CPU 31. Various functions of the control unit 30 are realized by the CPU 31 developing and executing a program stored in the EEPROM 38 on the RAM 37.

  In the printer 20 having such a configuration, in accordance with an instruction from the user via the operation panel 98, the control unit 30 controls each part of the printer 20 in order to perform recording based on the input image data to be recorded. . Specifically, resolution conversion processing, color conversion processing, halftone processing, and rasterization processing are performed on the input image data, and the ink ejection mode (ink ejection / non-ejection or ejection ink amount) by each nozzle 63 is specified. Recording data to be generated, and based on the generated recording data, main scanning in which the print head unit 60 is reciprocated along the main scanning direction while ejecting ink from the nozzles 63, and the recording medium TF is conveyed in the sub scanning direction. The sub-scan is repeatedly executed, whereby the image is recorded on the recording medium TF.

  The printer 20 is one of liquid ejecting apparatuses that eject ink as liquid. The print head 61 corresponds to a liquid ejecting unit that ejects white ink as a white liquid and color inks as a plurality of non-white liquids to record an image on the recording medium TF. In this specification, the operation in which the print head 61 ejects ink while moving relative to the recording medium TF in the forward or backward direction is referred to as “pass”.

  Further, in the present specification, “white” is not limited to white in a strict sense that is a surface color of an object that reflects 100% of all wavelengths of visible light, but as a so-called “white color”. It is assumed that a color called white is included for social reasons. “White” means, for example, (1) color measurement mode: spot color measurement, light source: D50, backing: Black, recording medium: transparent film using x-rite colorimeter eye-one Pro If it is colored, the label in the Lab system is on the a * b * plane within the circumference of the radius 20 and inside thereof, and L * is in the hue range represented by 70 or more, or (2) Minolta When using the colorimeter CM2022 manufactured by the company with color measurement in the measurement mode D502 ° field of view, SCF mode, and white background, the label in the Lab system is on the circumference of the radius 20 and inside it on the a * b * plane. , And L * is a color within the hue range represented by 70 or more, or (3) the color of the ink used as the background of the image as described in JP-A-2004-306591, a pure color It is not limited to white.

A-2. Image recording processing:
2 to 4 are explanatory diagrams showing an outline of the image recording process in the present embodiment. The image recording process described here is a process for recording a white image Iw and a color image Ic1 overlapping the white image Iw on the recording medium TF (FIG. 2A) as shown in FIG. 2C. is there. That is, the white image Iw is recorded directly on the recording medium TF, and the color image Ic is recorded on the white image Iw. The white image Iw is an image in which the entire area is filled with white (so-called solid image), and is recorded by discharging white ink. The color image Ic is an image composed of one or a plurality of colors other than white, and is recorded by discharging color ink.

  FIG. 3 shows an ink ejection mode in a region having a predetermined width (a width corresponding to the nozzle pitch NP) along the sub-scanning direction on the recording medium TF. In FIG. 3, a hollow circle indicates an ink discharge position (a position along the sub-scanning direction) by a certain nozzle 63, and a number in the circle indicates a pass order.

  Recording of an image in the area shown in FIG. 3 on the recording medium TF is completed by 12 passes (6 reciprocations of the print head 61). FIG. 4 shows the relationship between each pass and the recorded image. As shown in FIGS. 3 and 4, the white image Iw is recorded in the first to fourth passes (p1-p4). Hereinafter, in the present embodiment, the first to fourth passes are collectively referred to as “first recording operation”. Each pass constituting the first recording operation is executed across the sub-scan that conveys the recording medium TF by a quarter of the nozzle pitch NP. The recording resolution along the main scanning direction in each pass constituting the first recording operation is such a resolution that the recording of the line in the main scanning direction is completed in one pass. In addition, the discharge amount of the white ink from each nozzle 63 in each pass constituting the first recording operation is set to a value such that the recording of the white image Iw is temporarily completed by the first recording operation. Specifically, the ink discharge amount is set such that no gap is generated between the lines in the main scanning direction of the white ink dots formed by each pass. Therefore, the recording of the white image Iw is temporarily completed by the first recording operation.

  As shown in FIG. 3, the transport of the recording medium TF is executed after the first recording operation (p1-p4), and the fifth to eighth passes (p5-p8) are executed. Hereinafter, in the present embodiment, the fifth to eighth passes are collectively referred to as “second recording operation”. As shown in FIGS. 3 and 4, in the second recording operation, the recording of the color image Ic and the region other than the region overlapping the color image Ic in the white image Iw (hereinafter referred to as “non-overlapping region Aw”). The white ink is discharged in parallel. Here, in this embodiment, as shown in FIG. 2C, the non-overlapping area Aw is an area excluding the buffer area As in the area other than the area overlapping the color image Ic in the white image Iw. Yes. The buffer area As is an area set around the color image Ic, and is an ink dot (hereinafter, “L dot”) formed on the recording medium TF by the maximum discharge amount of ink from the nozzle 63 in the printer 20. It is an area | region which has the width | variety substantially the same as the diameter of a). As shown in FIG. 3, each pass constituting the second recording operation is executed across the sub-scan that conveys the recording medium TF by a quarter of the nozzle pitch NP. In addition, the recording resolution along the main scanning direction of the white ink and the color ink in each pass constituting the second recording operation is such a resolution that the recording of the line in the main scanning direction is completed in one pass. It is. Further, the discharge amount of the white ink from each nozzle 63 in each pass constituting the second recording operation is set to a value such that the ink discharge to the entire non-overlapping area Aw is temporarily completed by the second recording operation. The Specifically, the ink discharge amount is set such that no gap is generated between the lines in the main scanning direction of the white ink dots formed by each pass. On the other hand, since the color image Ic is recorded by the second recording operation and the third recording operation described later, the discharge amount of the color ink from each nozzle 63 for recording the color image Ic in each pass is relatively It is set to a small value (for example, half of the amount of white ink discharged from each nozzle 63 in each pass constituting the first recording operation). Therefore, the recording of the color image Ic is not completed by the second recording operation.

  As shown in FIG. 3, the transport of the recording medium TF is executed after the second recording operation (p5-p8), and the ninth to twelfth passes (p9-p12) are executed. Hereinafter, in the present embodiment, the ninth to twelfth passes are collectively referred to as a “third recording operation”. As shown in FIGS. 3 and 4, in the third recording operation, a color image Ic is recorded. As shown in FIG. 3, each pass constituting the third recording operation is executed across the sub-scan that conveys the recording medium TF by a quarter of the nozzle pitch NP. Further, the recording resolution along the main scanning direction of the color ink in each pass constituting the third recording operation is such a resolution that the recording of the line in the main scanning direction is completed in one pass. In addition, in each pass constituting the third recording operation, ink is ejected to a position (position along the transport direction) that fills a portion of the color image Ic that has not been recorded by the second recording operation. To be executed. Therefore, the recording of the color image Ic is completed by the third recording operation.

  3 and 4 show the ink discharge mode in a region having a predetermined width (a width corresponding to the nozzle pitch NP) along the sub-scanning direction on the recording medium TF. The same is true for the ink ejection mode for these areas. That is, in the area where the image is recorded by one set of the first to third recording operations, the recording of the white image Iw is completed as shown in FIG. 2B at the end of the first recording operation. At the end of the second recording operation, as shown in FIG. 2C, a color image Ic (a part of the color image Ic) is recorded and a white color is displayed in the non-overlapping area Aw on the white image Iw. Ink is ejected, and at the end of the third recording operation, recording of the color image Ic is also completed. Note that the first to third recording operation groups are repeated a predetermined number of times for recording on the entire recording medium TF in accordance with the relationship between the length of the nozzle array 65 and the length of the recording medium TF along the sub-scanning direction. Executed.

  FIG. 5 is an explanatory diagram illustrating a recording data generation method for realizing the image recording processing in the present embodiment. As shown in FIG. 5A, color ink recording data for recording the color image Ic is generated by the above-described color conversion processing, halftone processing, and the like for the color image data representing the color image Ic. The color image data is also subjected to white ink recording control processing for generating white ink recording data.

  FIG. 5B shows details of the white ink recording control process of FIG. As shown in the upper part of FIG. 5B, all dot generation processing is performed so that as much white ink as possible is ejected in each pass (p1-p4) constituting the first recording operation described above. Recording data for the first recording operation is generated such that dots are formed by discharging white ink at the printing pixels.

  On the other hand, as shown in the lower part of FIG. 5B, based on the input color image data, white ink is ejected to the non-overlapping area Aw in each pass (p5-p8) constituting the second recording operation described above. Recording data for the second recording operation as described above is generated. That is, the color image data is binarized to generate data for distinguishing the color image Ic region from the other regions, and the color image Ic region is set to 1 using the expansion filter illustrated in FIG. Dilate by pixel. As described above, this expansion process is performed in order to provide the buffer region As having a width substantially the same as the diameter of the L dot. Next, white ink is not ejected to the expanded color image Ic area (that is, equivalent to the sum of the color image Ic area and the buffer area As), and the remaining area (that is, the non-overlapping area Aw). Dot exclusion processing is performed so that white ink is ejected. Thereby, recording data for the second recording operation is generated such that dots are formed by discharging white ink at all the printing pixels in the non-overlapping area Aw.

  As described above, in the printer 20 of this embodiment, when the white image Iw and the color image Ic overlapping the white image Iw are recorded on the recording medium TF, the white ink for recording the white image Iw is recorded. A first recording operation (first to fourth passes) for performing ejection is executed, and after the first recording operation, ejection of color ink for recording the color image Ic and a non-overlapping area Aw (white image) A second recording operation (5th to 8th passes) is performed in parallel with the discharge of the white ink onto the area of Ic other than the area overlapping the color image Ic. Here, regarding the region (non-overlapping region Aw) other than the region overlapping the color image Ic in the white image Iw, the image quality can be improved as the amount of white ink discharged per unit area increases (more whiteness can be realized). ). When the amount of white ink discharged per unit area is small, the recording medium TF may show through. In particular, when a transparent film is used as the recording medium TF, light shielding may be insufficient. On the other hand, there are few such problems in the area overlapping the color image Ic in the white image Iw. In the printer 20 of the present embodiment, in the second recording operation performed after the first recording operation for recording the white image Iw, in addition to the recording of the color image Ic, the ink ejection to the non-overlapping area Aw Therefore, the amount of white ink discharged per unit area in the non-overlapping area Aw of the white image Iw can be increased, and the image quality of the white image Iw is reduced (the recording medium TF is not transparent and the light is not sufficiently shielded). Can be suppressed.

  In the present embodiment, since the color image Ic is also recorded in the second recording operation in which the white ink is applied to the non-overlapping area Aw, the amount of white ink discharged per unit area is the same as that of the present embodiment. After completing the recording of the white image Iw (that is, after completing the recording of the white image Iw by eight passes), the time required for recording is shortened as compared with the conventional recording method in which the recording of the color image Ic is started. can do.

  Further, in the present embodiment, a buffer area As having a width substantially the same as the diameter of the L dot is provided between the non-overlapping area Aw from which the white ink is ejected in the second recording operation and the color image Ic. Yes. That is, the non-overlapping area Aw is separated from the color image Ic by at least the L dot diameter. For this reason, it is possible to prevent the white ink ejected to the non-overlapping area Aw from being mixed with the color ink ejected for recording the color image Ic, and to suppress deterioration in the image quality of the color image Ic and the white image Iw. can do.

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

  In the above embodiment, the buffer area As is an area having substantially the same width as the diameter of the ink dot (L dot) formed on the recording medium TF by the maximum discharge amount of ink from the nozzle 63. The region As may be a region having a width larger than the diameter of the L dot. A filter (FIG. 5C) used for the expansion process may be selected according to the width of the buffer area As. For example, if the buffer area As is an area having a width twice the diameter of the L dot, a 5 × 5 filter is used instead of the 3 × 3 filter shown in FIG. That's fine. Note that it is not always necessary to provide the buffer area As between the non-overlapping area Aw and the color image Ic.

  The configuration of the printer 20 in the above embodiment is merely an example, and various modifications can be made. For example, in the above embodiment, the printer 20 performs recording using four color inks in addition to the white ink. However, the number of colors of the color ink used by the printer 20 and the colors themselves can be variously modified. . In the above embodiment, the printer 20 records an image on a transparent film as the recording medium TF. However, the printer 20 according to the present embodiment is not limited to a transparent film, but a translucent film, a color paper, a cloth, or the like. The recording of an image on any recording medium such as the above can be performed in the same manner.

  In addition, the number of passes constituting the first to third recording operations in the above embodiment can be variously modified. In the above embodiment, the recording of the color image Ic may be completed by the second recording operation, and the third recording operation may not be performed. In the above embodiment, the printer 20 performs so-called bidirectional printing in which ink is ejected in either the forward direction or the backward direction of the print head unit 60. The present invention can be similarly applied to so-called unidirectional printing in which ink is ejected in any one of the backward directions. In the above embodiment, the printer 20 repeatedly executes main scanning in which the print head unit 60 reciprocates in the main scanning direction and sub scanning in which the recording medium TF is conveyed in the sub scanning direction. However, the present invention is also applicable to a so-called line head type ink jet printer.

  In the above embodiment, the recording system may be configured by the printer 20 and the host computer connected to the printer 20, and a part of the function of the control unit 30 of the printer 20 may be realized by the host computer. In a broad sense, this recording system corresponds to a liquid ejecting apparatus that ejects white liquid and a plurality of non-white liquids to record an image on a recording medium.

  In addition, the present invention is not limited to white ink and color ink, but may be any device that discharges white and non-white liquids (including fluids in which functional material particles are dispersed and fluids such as gels). It can also be applied to devices other than inkjet printers. In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. Good.

20 ... Printer 30 ... Control unit 31 ... CPU
37 ... RAM
DESCRIPTION OF SYMBOLS 40 ... Print head unit conveyance mechanism 41 ... Motor 42 ... Drive belt 43 ... Pulley 44 ... Shaft 50 ... Recording medium conveyance mechanism 51 ... Motor 52 ... Platen 60 ... Print head unit 61 ... Print head 62 ... Holder 63 ... Nozzle 65 ... Nozzle Row 70 ... Ink cartridge 98 ... Operation panel

Claims (3)

A liquid ejection device comprising:
A liquid ejection unit that ejects a white liquid and a plurality of non-white liquids to record an image on a recording medium;
The liquid ejecting unit performs a first recording operation for ejecting the white liquid for recording the white image when recording a white image and a color image overlapping the white image on a recording medium. After the first recording operation, the discharge of the non-white liquid for recording the color image and the discharge of the white liquid to a region other than the region overlapping the color image in the white image are performed in parallel. A liquid ejection apparatus that executes a second recording operation. The liquid ejection device according to claim 1,
The region in which the white liquid is discharged in the second recording operation is separated from the color image by a dot diameter formed on a recording medium by the maximum discharge amount of the liquid discharge unit. apparatus. A liquid ejection method comprising:
A step of recording an image on a recording medium by discharging a white liquid and a plurality of non-white liquids;
The step of recording the image includes a first recording operation for discharging the white liquid for recording the white image when recording a white image and a color image overlapping the white image on a recording medium. And after the first recording operation, discharging the non-white liquid for recording the color image and discharging the white liquid to a region of the white image that does not overlap the color image are performed in parallel. A liquid ejection method, which is a step of performing a second recording operation.

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