JP2013103461A - Apparatus and method for ejecting liquid, and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image with a flat surface by an inkjet system that uses photoluminescence ink.SOLUTION: A liquid ejection apparatus includes a head that can eject the ink and a control part that controls ejection of the ink from the head to the printing medium. The head can eject the color ink and the photoluminescence ink. When ejecting the color ink and the photoluminescence ink on the printing medium, the control part sets the time difference in the ejectable timing to the same location between one ink and the other ink, and adjusts the ink ejection amount of the other ink according to the ink ejection amount of the ons side to the same location, and controls both inks to flatten the ink surface formed by both inks on the printing medium after ink ejection.

Description

  The present invention relates to a liquid ejection apparatus, a liquid ejection method, and a printed matter.

2. Description of the Related Art There is known a printing apparatus that performs recording by ejecting a liquid from a nozzle and landing ink droplets (dots) on a medium. In such a printing apparatus, printing is performed using a glossy ink having a metallic luster (for example, a metal ink containing metal particles, aluminum foil, or the like) in addition to a general color ink (for example, each color ink of KCMY). Sometimes. In metallic printing using such glittering ink, the balance between the metallic luster and color tone of the printed matter changes depending on the amount of metal particles contained in the metal ink. It has been difficult to achieve metallic printing with gloss.
In contrast, in metallic printing, an image is printed so that the printed shape is substantially mesh-like, and the size of the mesh is changed to adjust the amount of metal particles contained in the printed matter, thereby improving the metallic luster. A changing printing method has been proposed (for example, Patent Document 1).

JP-A-11-78204

According to the method of Patent Document 1, a metallic image having a good color tone can be printed. However, in a metallic image that is actually printed, there may be a region where many color ink dots and metal ink dots are formed and a region where few color ink dots and metal ink dots are formed. Therefore, depending on the printing method, partial unevenness may occur on the surface of the metallic image. When unevenness occurs on the surface of the image, the light reflected at that portion is scattered, so that when the image is viewed, the glossiness may be uneven and the image quality may appear to be degraded.
Further, for example, in a printed matter such as a gift certificate in which metallic printing is frequently used, it is desirable that light is regularly reflected at the metallic printing portion in order to prevent unauthorized copying. This is because when the light is specularly reflected at the metallic printed portion, the portion is copied as black at the time of copying, which prevents forgery of the gift certificate. Therefore, it is desirable that the surface of the metallic image is flat so that light is not easily scattered.

  An object of the present invention is to form an image having a flat surface by an inkjet method using glitter ink.

A main invention for achieving the above object is a liquid ejection apparatus comprising: a head capable of ejecting ink; and a control unit that controls ejection of the ink from the head onto a printing medium.
The head is capable of ejecting color ink and glitter ink, and when the control section ejects the color ink and glitter ink onto the printing medium, the head uses one ink and the other ink. A time difference is provided in the dischargeable timing to the same place, and the discharge amount of the other ink is adjusted according to the amount of discharge of the one ink to the same place. The liquid ejecting apparatus is characterized in that both inks are controlled so that the ink surfaces formed by the both inks are flattened.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is a block diagram illustrating an overall configuration of a printing apparatus. FIG. 2A is a diagram illustrating the configuration of the printer 1 according to the present embodiment. FIG. 2B is a side view illustrating the configuration of the printer 1 of the present embodiment. It is sectional drawing for demonstrating the structure of a head. It is explanatory drawing of the nozzle Nz provided in the head. It is a figure explaining the concept of the discharge method of the color ink and metal ink in 1st Embodiment. It is a figure which shows the flow of a color layer process in 1st Embodiment. It is a figure which shows the flow of a process of the metal layer in 1st Embodiment. It is a figure explaining the relationship between the image surface at the time of copying (copying) an image, and reflected light. It is a figure explaining the concept of the discharge method of the color ink and metal ink in 2nd Embodiment. It is a figure explaining adjustment of the glossiness of an image. It is a figure which shows the flow of a process of the color layer in 2nd Embodiment. It is a figure which shows the flow of a process of the metal layer in 2nd Embodiment. It is a figure explaining the dot formation of 3rd Embodiment. It is a figure explaining dot formation of a 3rd embodiment modification.

  At least the following matters will become clear from the description of the present specification and the accompanying drawings.

In a liquid ejection apparatus comprising: a head capable of ejecting ink; and a control unit that controls ejection of the ink from the head to a printing medium.
The head is capable of ejecting color ink and glitter ink, and when the control section ejects the color ink and glitter ink onto the printing medium, the head uses one ink and the other ink. A time difference is provided in the dischargeable timing to the same place, and the discharge amount of the other ink is adjusted according to the amount of discharge of the one ink to the same place. In addition, the liquid ejecting apparatus is characterized in that both inks are controlled so that the ink surface formed by the both inks is flattened.
According to such a liquid ejecting apparatus, an image having a flat surface can be formed by an ink jet method using glitter ink.

In such a liquid discharge apparatus, the control unit provides a time difference so that the dischargeable timing to the same place is earlier than the discharge timing of the color ink. It is desirable to be.
According to such a liquid ejecting apparatus, it is possible to form a high-quality metallic image with less gloss unevenness and difficult to perform illegal copying.

In such a liquid ejection apparatus, it is desirable that the total ejection amount of the two inks on the printing medium is substantially the same regardless of the ejection location of the two inks.
According to such a liquid ejection apparatus, it is possible to print a flat image having a uniform height from the printing medium to the image surface (ink surface) at an arbitrary place.

In the liquid ejecting apparatus, the head can further eject clear ink, and the control unit ejects the clear ink when ejecting the color ink and the glitter ink onto the printing medium. It is desirable to control so that ink is ejected after ejection.
According to such a liquid ejecting apparatus, it is easy to form an image with a flat surface and little gloss unevenness even when the medium is uneven.

In this liquid ejection apparatus, the control unit ejects the clear ink onto the printing medium, ejects at least one of the color ink and the glitter ink onto the print medium, and further onto the liquid ink. It is desirable to control to discharge clear ink.
According to such a liquid ejecting apparatus, it is possible to print an image with higher gloss.

  In a liquid discharge method of a liquid discharge apparatus, comprising: a head capable of discharging ink; and a control unit that controls discharge of the ink from the head to a printing medium. One ejection step, corresponding to the ejection amount of one of the color ink and the glitter ink, and the other ink non-ejection at the same ejection location or the other ink ejection according to the one ejection amount. And a liquid discharging method characterized by comprising the steps of:

  Further, in the printed matter on which an image using the color ink and the glitter ink on the printing medium is formed, the color ink and the glitter ink have a laminated portion, and the color ink and the glitter ink. The printed matter is characterized in that the image forming surface is substantially flat.

=== Basic configuration ===
One form of a liquid ejection apparatus for carrying out the invention is a printing apparatus that prints an image by ejecting a liquid such as ink onto a medium. In the present embodiment, an ink jet printer (printer 1) will be described as an example.

<Configuration of Printer 1>
FIG. 1 is a block diagram illustrating the overall configuration of the printing apparatus.
The printer 1 is a printing device that prints characters and images on a printing medium such as paper, cloth, and film (hereinafter also simply referred to as a medium), and is connected to a computer 110 that is an external device so as to be communicable.

  A printer driver is installed in the computer 110. The printer driver is a program for causing a display device to display a user interface and converting image data output from an application program into print data. This printer driver is recorded on a recording medium (computer-readable recording medium) such as a flexible disk FD or a CD-ROM. Also, the printer driver can be downloaded to the computer 110 via the Internet. This program is composed of codes for realizing various functions.

  In order for the computer 110 to print an image on the printer 1, data corresponding to the image to be printed is generated and output to the printer 1. Therefore, it can be said that the computer 110 is a control unit of the printing apparatus.

  The printer 1 includes a transport unit 20, a carriage unit 30, a head unit 40, a detector group 50, and a controller 60. The controller 60 controls each unit based on the recording data received from the computer 110 which is a print recording apparatus control unit, and prints an image on a medium. The situation in the printer 1 is monitored by the detector group 50, and the detector group 50 outputs the detection result to the controller 60. The controller 60 controls each unit based on the detection result output from the detector group 50.

<Transport unit 20>
FIG. 2A is a diagram illustrating the configuration of the printer 1 according to the present embodiment. FIG. 2B is a side view illustrating the configuration of the printer 1 of the present embodiment.
The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined direction (hereinafter referred to as a transport direction). Here, the transport direction is a direction that intersects the moving direction of the carriage. The transport unit 20 includes a paper feed roller 21, a transport motor 22, a transport roller 23, a platen 24, and a paper discharge roller 25 (FIGS. 2A and 2B).
The paper feed roller 21 is a roller for feeding the paper S inserted into the paper insertion slot into the printer. The transport roller 23 is a roller that transports the paper S fed by the paper feed roller 21 to a printable region, and is driven by the transport motor 22. The operation of the transport motor 22 is controlled by a controller 60 on the printer side. The platen 24 is a member that supports the paper S being printed from the back side of the paper S. The paper discharge roller 25 is a roller for discharging the paper S to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area.

<Carriage unit 30>
The carriage unit 30 is for moving (also referred to as “scanning”) the carriage 31 to which the head unit 40 is attached in a predetermined direction (hereinafter referred to as a moving direction). The carriage unit 30 includes a carriage 31 and a carriage motor 32 (also referred to as a CR motor) (FIGS. 2A and 2B).
The carriage 31 can reciprocate in the moving direction and is driven by a carriage motor 32. The operation of the carriage motor 32 is controlled by a controller 60 on the printer side. The carriage 31 detachably holds a cartridge that stores liquid (ink) for printing an image.

<Head unit 40>
The head unit 40 is for ejecting ink onto the paper S. The head unit 40 includes a head 41 having a plurality of nozzles. The head 41 is provided on the carriage 31, and when the carriage 31 moves in the movement direction, the head 41 also moves in the movement direction. Then, by intermittently ejecting ink while the head 41 is moving in the moving direction, dot lines (raster lines) along the moving direction are formed on the paper.

  FIG. 3 is a cross-sectional view showing the structure of the head 41. The head 41 includes a case 411, a flow path unit 412, and a piezo element group PZT. The case 411 houses the piezo element group PZT, and the flow path unit 412 is joined to the lower surface of the case 411. The flow path unit 412 includes a flow path forming plate 412a, an elastic plate 412b, and a nozzle plate 412c. The flow path forming plate 412a is formed with a groove portion serving as a pressure chamber 412d, a through hole serving as a nozzle communication port 412e, a through port serving as a common ink chamber 412f, and a groove portion serving as an ink supply path 412g. The elastic plate 412b has an island portion 412h to which the tip of the piezo element PZT is joined. An elastic region is formed by an elastic film 412i around the island portion 412h. The ink stored in the ink cartridge is supplied to the pressure chamber 412d corresponding to each nozzle Nz via the common ink chamber 412f. The nozzle plate 412c is a plate on which the nozzles Nz are formed.

  The piezo element group PZT has a plurality of comb-like piezo elements (drive elements), and is provided by the number corresponding to the nozzles Nz. When a drive signal COM is applied to the piezoelectric element by a wiring board (not shown) on which the head controller HC and the like are mounted, the piezoelectric element expands and contracts in the vertical direction according to the potential of the drive signal COM. When the piezo element PZT expands and contracts, the island portion 412h is pushed toward the pressure chamber 412d or pulled in the opposite direction. At this time, the elastic film 412i around the island portion 412h is deformed, and the pressure in the pressure chamber 412d rises and falls, thereby ejecting ink droplets from the nozzles.

FIG. 4 is an explanatory diagram of the nozzle Nz provided on the lower surface of the head 41. On the nozzle surface, a color composed of a yellow nozzle row Y for discharging yellow ink, a magenta nozzle row M for discharging magenta ink, a cyan nozzle row C for discharging cyan ink, and a black nozzle row K for discharging black ink. An ink nozzle row and a metal ink nozzle row Me that ejects glitter ink (for example, metal ink described later) are formed. Further, a nozzle row that ejects ink of a color other than black (K), cyan (C), magenta (M), yellow (Y), and metal (Me) may be provided. For example, there may be a nozzle row that ejects clear (CL) or white (W) ink.
The head 41 may be integrated with a color ink discharge portion, a glitter ink discharge portion, a clear ink discharge portion, or the like, or may be separate from each other. Alternatively, any one of them may be separate and the rest may be integrated.

  As shown in FIG. 4, each of the color (KCMY) and metal (Me) nozzle arrays is configured by nozzles Nz serving as ejection openings for ejecting ink of each color being arranged at a predetermined interval D in the transport direction. ing. Each nozzle row includes 180 nozzles Nz # 1 to # 180. Note that the actual number of nozzles in each nozzle row is not limited to 180. For example, the number of nozzles may be 90 or 360. In FIG. 4, the nozzle rows are arranged in parallel along the moving direction, but may be arranged in a vertical row along the transport direction. Further, instead of having one nozzle row for each color of KCMY-Me, it may be configured to have a plurality of nozzle rows for each color.

<Detector group 50>
The detector group 50 is for monitoring the status of the printer 1. The detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, an optical sensor 54, and the like (FIGS. 2A and 2B).
The linear encoder 51 detects the position of the carriage 31 in the moving direction. The rotary encoder 52 detects the rotation amount of the transport roller 23. The paper detection sensor 53 detects the position of the leading edge of the paper S being fed. The optical sensor 54 detects the presence or absence of the paper S at the opposing position by the light emitting unit and the light receiving unit attached to the carriage 31, for example, detects the position of the edge of the paper while moving, and sets the width of the paper. Can be detected. The optical sensor 54 also has a leading edge (an end portion on the downstream side in the transport direction, also referred to as an upper end) and a rear end (an end portion on the upstream side in the transport direction, also referred to as the lower end) of the paper S depending on the situation. It can be detected.

<Controller 60>
The controller 60 is a control unit (control unit) for controlling the printer 1. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64 (FIG. 1).
The interface unit 61 transmits and receives data between the computer 110 that is an external device and the printer 1. The CPU 62 is an arithmetic processing device for performing overall control of the printer 1. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and is configured by a storage element such as a RAM or an EEPROM. Then, the CPU 62 controls each unit such as the transport unit 20 via the unit control circuit 64 in accordance with a program stored in the memory 63.

<Printer operation>
The printing operation of the printer 1 will be briefly described. The controller 60 receives a print command from the computer 110 via the interface unit 61 and controls each unit to perform a paper feed process, a dot formation process, a transport process, and the like.

  The paper feed process is a process of supplying paper to be printed into the printer and positioning the paper at a print start position (also referred to as a cue position). The controller 60 rotates the paper feed roller 21 and sends the paper to be printed to the transport roller 23. Subsequently, the transport roller 23 is rotated, and the paper fed from the paper feed roller 21 is positioned at the print start position.

  The dot formation process is a process of forming dots on paper by intermittently ejecting ink from a head that moves in the movement direction (scanning direction). The controller 60 moves the carriage 31 in the moving direction, and ejects ink from the head 41 based on the print data while the carriage 31 is moving. When the ejected ink droplets land on the paper, dots are formed on the paper, and a dot line composed of a plurality of dots along the moving direction is formed on the paper.

  The carrying process is a process of moving the paper relative to the head in the carrying direction. The controller 60 rotates the transport roller 23 to transport the paper in the transport direction. By this carrying process, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation process.

The controller 60 alternately repeats the dot formation process and the conveyance process until there is no more data to be printed, and gradually prints an image composed of dot lines on paper. When there is no more data to be printed, the paper discharge roller 25 is rotated to discharge the paper. The determination of whether or not to discharge paper may be based on a paper discharge command included in the print data.
The same processing is repeated when printing on the next paper, and the printing operation is terminated when not printing.

  In the printing operation of the printer 1, ink droplets are ejected from the nozzles during the forward path moving from the right side (home position) in the movement direction (scanning direction) to the left side, and the head 41 moves from the left side to the right side in the movement direction. There are sometimes “unidirectional printing” in which ink droplets are not ejected from the nozzles and “bidirectional printing” in which ink droplets are ejected from the nozzles during the forward pass and the return pass. The printing method described in the present embodiment is compatible with both “unidirectional printing” and “bidirectional printing” printing operations.

<About glitter ink used for printing>
In this embodiment, the image is made glossy by performing printing using the glitter ink that emits gloss by reflecting light. A metal ink containing metallic particles such as silver particles and aluminum particles will be described as the glitter ink.

  The metal ink containing aluminum particles can obtain a bright metallic luster on the printing surface, but since the aluminum particles are easily oxidized, the printing surface may be whitened over time. On the other hand, the metal ink containing silver particles has a problem that the metallic luster color tends to be darker and the cost is higher than the ink containing aluminum particles, but has the property of being hardly oxidized and having excellent stability. Although the metal ink used at the time of printing can be selected according to the use of printing, each embodiment of this specification demonstrates printing using the metal ink containing silver particles.

  As the solvent of the metal ink, pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, or distilled water is used. As long as it does not interfere with the dispersion of the metal particles, ions or the like may be present in the water. Moreover, you may contain surfactant, a polyhydric alcohol, a pH adjuster, resin, a coloring material, etc. as needed.

  Silver particles contained in the ink composition of the present embodiment are particles containing silver as a main component. For example, the silver particles may contain other metals, oxygen, carbon and the like as subcomponents. The purity of silver in the silver particles can be, for example, 80% or more. The silver particles may be an alloy of silver and another metal. Further, the silver particles in the ink composition may be present in a colloid (particle colloid) state. When the silver particles are dispersed in a colloidal state, the dispersibility is further improved, and can contribute to, for example, improving the storage stability of the ink composition.

  The particle size d90 in the particle size accumulation curve of the silver particles is 50 nm or more and 1 μm or less. Here, the particle size accumulation curve is a statistically calculated result obtained by measuring the diameter of the silver particles dispersed in a liquid such as an ink composition and the number of particles present. It is a kind of curve obtained by processing. The particle size accumulation curve in the present specification is a particle having a small diameter with respect to the mass of the particle (the product of the volume, the density of the particle, and the number of particles when the particle is regarded as a sphere). The value (integrated value) integrated from the large to large particles is plotted on the vertical axis. The particle size d90 is 90% (0.90) when the vertical axis is normalized (the total mass of the measured particles is 1) in the particle size accumulation curve. The value on the horizontal axis, that is, the diameter of the particle. In this case, the diameter of the silver particles may be the diameter of the silver particles themselves, or may be the diameter of the particle colloid when the silver particles are dispersed in a colloidal form.

  The particle size accumulation curve of the silver particles can be obtained, for example, by using a particle size distribution measuring apparatus based on the dynamic light scattering method. In the dynamic light scattering method, dispersed silver particles are irradiated with laser light, and the scattered light is observed with a photon detector. Generally, dispersed silver particles usually have a Brownian motion. The speed of movement of silver particles is larger for particles having a larger particle diameter and smaller for particles having a smaller particle diameter. When silver particles that are in Brownian motion are irradiated with laser light, fluctuations corresponding to the Brownian motion of each silver particle are observed in the scattered light. This fluctuation is measured, an autocorrelation function is obtained by a photon correlation method or the like, and the diameter of silver particles and the frequency (number) of silver particles corresponding to the diameter can be obtained by using a cumulant method and a histogram method analysis. . In particular, a dynamic light scattering method is suitable for a sample containing submicron-sized silver particles, and a particle size accumulation curve can be obtained relatively easily by the dynamic light scattering method. Examples of the particle size distribution measuring apparatus based on the dynamic light scattering method include Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.), ELSZ-2, DLS-8000 (above, manufactured by Otsuka Electronics Co., Ltd.), LB-550 ( Manufactured by HORIBA, Ltd.).

<About print images>
In this embodiment, an image (original image) to be printed is composed of a metallic image portion printed with metal ink (Me) and a color image portion printed with color ink (KCMY). This color image portion is expressed in three colors of RGB, and is printed with four color inks of KCMY at the time of printing. As described above, printing is performed using a color ink other than black (K), cyan (C), magenta (M), and yellow (Y), for example, clear (CL) or white (W). May be.
In this embodiment, for the sake of explanation, the original image is divided into two types of layers, a layer where a metallic image is formed (metal layer) and a layer where a color image is formed (color layer).

=== First Embodiment ===
<Regarding Dot Formation in the First Embodiment>
In the first embodiment, an image is printed using metal ink (bright ink) and color ink. At this time, the height of the metal ink dots formed on the medium with the metal ink from the medium surface and the height of the color ink dots formed on the medium with the color ink from the medium surface are made uniform. That is, the amount of ink ejected is controlled so that the surface (also referred to as ink surface or image forming surface) of the image formed on the medium after both the metal ink and the color ink are ejected becomes flat. Is done.

  Before describing specific processing during printing, an outline of the first embodiment will be described. FIG. 5 is a diagram illustrating the concept of the color ink and metal ink ejection method in the first embodiment. For the sake of explanation, it is assumed that printing is performed using only one color of cyan (C) as the color ink. FIG. 5A shows pixels in which color ink dots are formed in a predetermined region in the color layer. FIG. 5B shows pixels in which metal ink dots are formed in the same region as that of FIG. 5A in the metal layer. FIG. 5C shows a state where FIGS. 5A and 5B are superimposed. In addition, the area | region for 1 square enclosed with the broken line of a figure represents 1 pixel.

  First, the printer driver prints color ink (cyan (C) ink) dots at a predetermined location in the medium (for example, a 4 × 4 pixel area shown in FIG. 5A) according to image data for printing a color image. The data for discharging is generated. In the color layer shown in FIG. 5A, cyan (C) ink dots are ejected to the pixels indicated by black circles. In this state, since pixels where dots are formed and pixels where dots are not formed are adjacent to each other, irregularities occur on the image surface (ink surface). For example, in the AA cross section of FIG. 5A, ink dots are formed on the first and third pixels from the left, but no ink dot is formed on the second and fourth pixels from the left. Therefore, as indicated by the thick line portion of the AA cross section, the image surface has a shape with irregularities. The “image surface” in the figure represents the surface of the image in a state where the dots are flattened after a predetermined time has elapsed since the ink dots were formed on the medium. That is, the shape of the dot shown in the AA cross section of FIG. 5A schematically represents the state of the dot when the ink has landed, and then the dot is crushed by its own weight, so The space is filled, and an image surface having a flat portion as shown in the figure is formed.

  When the image surface is uneven, the light incident on the image surface is scattered and reflected in various directions, so that it appears that uneven gloss is generated on the image surface.

  Therefore, the printer driver discharges metal ink (Me) dots to pixels in which color ink (cyan (C) ink) dots are not formed in that place (4 × 4 pixel region shown in FIG. 5A). Generate data for In the metal layer shown in FIG. 5B, metal ink dots are formed in the pixels indicated by white circles.

  A state in which the color layer (FIG. 5A) and the metal layer (FIG. 5B) are superimposed is represented as shown in FIG. 5C. In FIG. 5C, color ink dots (black circles) or metal ink dots (white circles) are formed on all the pixels in the 4 × 4 pixel region. That is, since all the pixels are filled with ink dots, the unevenness of the image surface that occurred in FIG. 5A is flattened. For example, in the BB cross section of FIG. 5C, color ink dots (black circles) are formed on the first and third pixels from the left, and metal ink dots (white circles) are formed on the second and fourth pixels. Therefore, the image surface after a predetermined time elapses tends to be flat as shown by the thick line portion of the BB cross section. Since the light incident on the plane is almost regularly reflected, uneven glossiness is less likely to occur on the image surface.

  In FIG. 5C described above, an example in which ink dots are formed on all pixels has been described. However, if ink dots are formed on almost all pixels, the image surface can be flattened. Therefore, it is not always necessary to form ink dots on all pixels.

<Print processing>
Next, a specific print processing method in the first embodiment will be described. In the printing process, a process for a color layer and a process for a metal layer are performed, and finally print data of an image to be printed is generated.
Prior to the start of printing, the computer 110 and the printer 1 are first connected (see FIG. 1), and the printer driver stored in the CD-ROM included with the printer 1 (or downloaded from the printer manufacturer's website) Printer driver) is installed in the computer 110. This printer driver includes a code for causing a computer to execute each process of FIG.

The printer driver receives original image data from the application program, converts it into print data in a format that can be interpreted by the printer 1, and outputs the print data to the printer 1. When converting original image data into print data, the printer driver performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, and the like. Note that a printer driver may be installed in the printer 1 and various processes may be performed on the printer side.
Details of various processes performed by the printer driver will be described below.

(Color layer processing)
FIG. 6 shows a process flow of the color layer in the first embodiment. The color layer processing is performed by executing the steps S101 to S105. Each process is executed based on a command from the printer driver.
When printing is started by the user instructing printing from the application program, the printer driver is called to receive image data (original image data) to be printed from the application program (S101), and for the image data Resolution conversion processing (S102) is performed.

  The resolution conversion process (S102) is a process for converting image data (text data, image data, etc.) to a resolution (print resolution) for printing on a medium. For example, when the print resolution is specified as 720 × 720 dpi, the vector format image data received from the application program is converted into bitmap format image data with a resolution of 720 × 720 dpi. In addition, each pixel data of the image data after the resolution conversion process is composed of data of each gradation (for example, 256 gradations) represented by the RGB color space.

  Next, the printer driver performs color conversion processing (S103). The color conversion process is a process of converting image data in accordance with the color space of the ink color of the printer 1. Here, image data in the RGB color space is converted into image data in the KCMY color space. This color conversion process is performed based on a 3D-LUT in which the gradation value of RGB data is associated with the gradation value of KCMY data. Thereby, image data in the KCMY color space is obtained. The pixel data after the color conversion process is 256-bit 8-bit data represented by the KCMY color space.

  After the color conversion process (S103), the printer driver performs a halftone process (S104). The halftone process is a process of converting high gradation number data into low gradation number data that can be formed by the printer 1. Here, it is assumed that print image data of 256 gradations is converted into 1-bit data indicating 2 gradations. As a halftone processing method, a dither method, an error diffusion method, and the like are known, and this embodiment also performs such a halftone processing. The halftone processed data has a resolution equivalent to the recording resolution (for example, 720 × 720 dpi). In the image data after halftone processing, 1-bit pixel data corresponds to each pixel, and this pixel data is data (data corresponding to FIG. 5A) indicating the dot formation status (the presence or absence of dots) in each pixel. Become.

  Next, the printer driver performs rasterization processing (S105). The rasterization process is a process of changing the order of arrangement of pixel data on the print image data to the order of data to be transferred to the printer 1. For example, the pixel data is rearranged according to the arrangement order of the nozzles in each nozzle row. Thereafter, the printer driver generates print data of a color image by adding control data for controlling the printer 1 to the pixel data, and transmits the print data to the printer 1.

(Metal layer processing)
FIG. 7 shows a process flow of the metal layer in the first embodiment. The metal layer processing is performed by executing the steps S151 to S154. Each process is executed based on a command from the printer driver.

  In the processing of the metal layer, first, pixel data (data corresponding to FIG. 5A) of the color layer after the halftone processing in the above-described step S104 is acquired by the printer driver (S151). Print data for discharging metal ink is generated based on the pixel data of the color layer.

  After the pixel data of the color layer is acquired, a pixel other than the pixel from which the color ink indicated by the pixel data is ejected is selected (S152). That is, pixel data corresponding to the above-described FIG. 5B is generated, and a pixel to be ejected with metal ink (shining ink) is determined. Specifically, the gradation value of each pixel is examined in the pixel data of the color layer. When the pixel data of the color image is represented as 1-bit data as in the above example, a predetermined amount of color ink is ejected to the pixel having the gradation value [1], and each color ink dot has the same size Is formed. On the other hand, since color ink is not ejected to the pixel having the gradation value [0], no color ink dot is formed. The printer driver detects a pixel having a gradation value [0] and determines the pixel as a metal ink ejection pixel.

Then, the discharge amount of the metal ink for each pixel is determined so that the total amount of the color ink and the metal ink discharged to each pixel is substantially equal (S153). In the present embodiment, data that causes metal ink to be ejected at a gradation value [1] is generated for the pixel represented by the gradation value [0] of the color layer. As a result, color ink dots or metal ink dots are formed with gradation value [1] in each pixel. That is, pixel data is generated so that all pixels constituting the image are filled with color ink dots or metal ink dots of the same size. In other words, a large amount of metal ink is ejected at pixels where the amount of color ink ejected is relatively small relative to the total amount of ink ejected per pixel (pixels where the color ink ejection amount is zero in this embodiment). Is done. On the other hand, data is generated so that a small amount of metal ink is ejected in a pixel having a relatively large amount of color ink ejection (in this embodiment, the amount of metal ink ejection is zero). As a result, an image having a flat surface is formed. Thereafter, the printer driver performs rasterization processing in the same manner as in S105 described above (S154). Then, control data is added to the pixel data, and is sent to the printer 1 as print data of a metallic image. In the metal layer process, the color conversion process (S103) as performed in the color layer process may not be performed. This is because the metal ink color (Me) cannot be expressed by a combination of color inks (KCMY) and is therefore treated as a special color.

  The printer 1 performs a printing operation according to the received print data. Specifically, the controller 60 of the printer 1 controls the transport unit 20 and the like according to the control data of the received print data, controls the head unit 40 according to the pixel data of the print data, and sets the color from each nozzle provided in the head 41. Ink and metal ink are ejected.

<Effects of First Embodiment>
In the first embodiment, a larger amount of metal ink is ejected to a pixel with a relatively small amount of color ink ejection relative to the total amount of ink ejected to each pixel. Conversely, pixels with a relatively large amount of color ink ejected eject less metal ink. That is, the ejection amount of the other ink to the same location (region) is adjusted according to the magnitude of the ejection amount of one ink to a certain location (predetermined region). In other words, control is performed so that the sum of the amount of color ink ejected to each area constituting the image and the amount of metal ink (brilliant ink) becomes substantially equal regardless of the ejection location. As a result, the surface (ink surface, image forming surface) of the formed image is flattened, and light incident on the image surface is easily reflected regularly, so that a high-quality image with little gloss unevenness can be formed. .

  Further, illegal reflection can be prevented by regular reflection of light on the image surface. FIG. 8 is a diagram for explaining the relationship between the image surface and reflected light when an image is copied. When copying an image using a general copying machine, a light source is set at a predetermined angle (for example, 45 degrees) with respect to the normal direction of the image, and the incident angle is constant using the light source. In this way, the image surface is irradiated with light. A light receiving portion is provided at a position of 0 degrees with respect to the normal direction of the image, and the light reflected in the direction of 0 degrees on the image surface is received. The intensity of the received light is measured for each RGB component, so that the color at that portion can be reproduced.

  FIG. 8A is a conceptual diagram in the case of copying an image (general image) having an uneven surface as in the AA cross section of FIG. 5A. In this case, the light irradiated from the light source (incident light) is reflected on the image surface, but the reflected light is scattered because the surface is uneven. Of the scattered reflected light, only the light reflected in the direction of 0 degrees with respect to the normal direction of the image is detected by the light receiving unit. Thereby, the color in the said part is reproduced.

  On the other hand, FIG. 8B is a conceptual diagram in the case of copying an image with a flat surface (an image having a gloss like a mirror surface) as in the BB cross section of FIG. 5C. In this case, since the incident light is substantially regularly reflected on the image surface, for example, light incident at an angle of 45 degrees is reflected at an angle of 45 degrees. That is, if the image surface is flat, the component of incident light that reflects in the normal direction is very small. Therefore, since it is difficult for the light receiving unit to detect light, the portion is reproduced as black in the copy image.

  For this reason, in gift vouchers that frequently use metallic printing, flattening the metallic printing part makes it impossible to accurately reproduce the part, so it is easy to prevent counterfeiting such as unauthorized copying There is.

=== Second Embodiment ===
In the first embodiment, the case where the color ink dot and the metal ink dot are not formed in the same pixel, that is, the example in which the metal ink is ejected to the pixel where the color ink is not ejected has been described. In contrast, in the second embodiment, a case will be described in which color ink dots and metal ink dots are formed on the same pixel. In this case, there is a time difference between the timing at which one ink and the other ink can be ejected to the same location (pixel) so that the other ink dot is formed on one ink dot.
In this embodiment, the amount of the other ink discharged to the same location (pixel) is adjusted according to the magnitude of the amount of the ink discharged to the predetermined location (pixel), and the medium is discharged after both inks are discharged. The surface (ink surface) of the image formed thereon is flattened.
Note that the basic configuration of a printing apparatus used for printing an image is the same as that of the printer 1 of the first embodiment.

<Regarding Dot Formation in Second Embodiment>
FIG. 9 is a diagram illustrating the concept of the color ink and metal ink ejection method according to the second embodiment. For the sake of explanation, it is assumed that printing is performed using only one color of cyan (C) as the color ink. FIG. 9A shows pixels in which color ink dots are formed in a predetermined region in the color layer. FIG. 9B shows a pixel in which metal ink dots are formed in the same region as FIG. 9A in the metal layer. FIG. 9C shows a state where FIGS. 9A and 9B are superimposed. Note that a region corresponding to one square in the figure represents one pixel. The “image surface” represents a flattened image surface after a predetermined time has elapsed, as described with reference to FIG.

  Also in the second embodiment, the printer driver uses color ink (cyan (C) ink) in a predetermined area (4 × 4 pixel area shown in FIG. 9A) in the medium according to image data for printing a color image. ) Generate data for ejecting dots. Here, it is assumed that color ink dots are formed with four gradations of small dots, medium dots, large dots, and no dots. Since the size of the dot formed for each pixel (height from the medium surface to the upper end of the dot) is different, irregularities occur on the image surface. For example, in the AA cross section of FIG. 9A, large dots, no dots, small dots, and medium dots are formed in order from the left pixel. Therefore, the surface of the image after a predetermined time has a concavo-convex shape as indicated by the thick line portion of the AA cross section, and the reflected light is likely to be scattered as described above. It becomes easy.

  Therefore, in the second embodiment, the ejection amount of the metal ink dots is determined for each pixel so that the total height when the color ink dots and the metal ink dots ejected to each pixel are superimposed is approximately the same. Is done. That is, the discharge amount of the metal ink is adjusted so that the total amount of ink applied for each pixel becomes substantially equal. In other words, the discharge amount of the metal ink dot is decreased in a pixel having a relatively large discharge amount of color ink dots, and conversely, the discharge amount of the metal ink dot is increased in a pixel having a relatively small discharge amount of the color ink dot. As described above, the discharge amount of the metal ink is determined.

  Specifically, as shown in the metal layer of FIG. 9B, extra large metal ink dots are formed on the pixels in which color ink dots are not formed in FIG. 9A. Also, large dots of metal ink are formed on pixels where small dots of color ink are formed, medium dots of metal ink are formed on pixels where medium dots of color ink are formed, and large dots of color ink are formed. Small dots of metal ink are formed on the pixels to be formed.

  A state in which the color layer (FIG. 9A) and the metal layer (FIG. 9B) are superimposed is represented as shown in FIG. 9C. In FIG. 9C, ink dots are formed for all the 4 × 4 pixel regions. The color ink dot and / or metal ink dot formed on each pixel makes the height from the medium to the image surface constant. Thereby, the unevenness | corrugation of the image surface which has generate | occur | produced in FIG. 9A is planarized. For example, in the BB cross section of FIG. 9C, large dots of color ink and small dots of metal ink are formed on the first pixel from the left side. In addition, color ink dots are not formed on the second pixel from the left side, and extra large dots of metal ink are formed. Further, a small dot of color ink and a large dot of metal ink are formed on the third pixel from the left side. Further, the middle dot of color ink and the middle dot of metal ink are formed on the fourth pixel from the left side. Note that ink dots are formed in almost all pixels as in the first embodiment.

  Thus, the height from the medium surface to the image surface is made uniform by making the total amount of ink ejected for each pixel substantially equal. Therefore, the image surface becomes planar as shown by the thick line portion of the BB cross section. Since the light incident on the plane is almost regularly reflected, uneven glossiness is less likely to occur on the image surface.

  In the present embodiment, when ink is ejected according to the print data, the ejection timing of the metal ink (brilliant ink) is controlled to precede the ejection timing of the color ink. This is because if the metal ink is ejected later, metal ink dots are formed on the color ink dots, making it difficult to see the image of the color ink.

  In the present embodiment, the glossiness of the entire image can be adjusted by changing the size of the metal ink dots formed in each pixel. FIG. 10 is a diagram for explaining adjustment of glossiness of an image.

  10A is a view corresponding to the BB cross section of FIG. 9C. Since the image surface is flat, the incident light is easily regularly reflected, and an image with less gloss unevenness is printed. However, since a part of the incident light is absorbed on the image surface, the intensity of the reflected light is weaker than the incident light.

  On the other hand, FIG. 10B is a diagram illustrating a case where the amount of metal ink discharged to each pixel is increased as compared to FIG. 10A. Similar to the case of FIG. 10A, the image surface can be formed flat by adjusting the total discharge amount of the metal ink and the color ink in each pixel. Occurrence can be suppressed. Further, in FIG. 10B, the amount of metal ink forming an image is larger than in the case of FIG. 10A. That is, the amount of metal particles present on the medium is also increasing. Therefore, the light incident on the image surface is more easily reflected. This is because as the amount of metal particles contained in the ink dots constituting the image increases, the amount of light reflected without being absorbed on the image surface increases. As a result, the intensity of the reflected light becomes stronger than in the case of FIG. 10A, and a more glossy image can be printed.

  As described above, by adjusting the discharge amount of the metal ink, it is possible to form an image with less gloss unevenness and a desired glossiness. Further, since the image surface is formed flat, the metallic print portion is reproduced in black when performing color copying or the like, so that unauthorized copying can be suppressed.

<Print processing>
A specific print processing method in the second embodiment will be described. In the printing process, a process for a color layer and a process for a metal layer are performed, and finally print data of an image to be printed is generated.

(Color layer processing)
FIG. 11 shows a flow of color layer processing in the second embodiment. The color layer processing is performed by executing the steps S201 to S205. Each process is executed based on a command from the printer driver.
When printing is started, the printer driver receives image data (original image data) to be printed from the application program (S201), and resolution conversion processing (S202) is performed. The resolution conversion process is the same as S102 in the first embodiment. Subsequently, image data in the RGB color space is converted into image data in the KCMY color space by color conversion processing (S203). The color conversion process is the same as that in S103 of the first embodiment, and the pixel data after the color conversion process is expressed by 256-bit 8-bit data represented by the KCMY color space.

  Next, the printer driver performs halftone processing (S204). Here, it is assumed that print image data of 256 gradations is converted into 2-bit data indicating 4 gradations by halftone processing. In this embodiment, the image data after halftone processing corresponds to 2-bit pixel data for each pixel, and this pixel data is data indicating the dot formation status at each pixel (corresponding to FIG. 9A). Pixel data). For example, a large color dot is formed in a pixel with pixel data [11], a medium color dot is formed in a pixel [10], a small color dot is formed in a pixel [01], and [00]. No dot is formed in this pixel.

  After the halftone processing, the printer driver performs rasterization processing (S205). Thereafter, print data is generated by adding control data for controlling the printer 1 to the pixel data, and the print data is transmitted to the printer 1.

(Metal layer processing)
FIG. 12 shows a processing flow of the metal layer in the second embodiment. The metal layer processing is performed by executing the steps S251 to S255. Each process is executed based on a command from the printer driver.

In the processing of the metal layer, first, pixel data of the color layer after the halftone processing in S204 described above is acquired (S251).
From the acquired pixel data of the color layer, the discharge amount of the color ink is calculated for each pixel (S252). As described above, the pixel data of the color layer is represented as 2-bit data by halftone processing. Therefore, the ink discharge amount for each color is represented by four types of data for each pixel, and the color ink discharge amount for each pixel is calculated from this data.

  Subsequently, the glossiness of the image to be printed is set (S253). The glossiness is set by the user himself / herself through a user interface (not shown). For example, three levels of gloss, strong, medium, and weak, are set, and the intensity of reflected light in the printed image is set by the user selecting a desired gloss level. Note that the glossiness may be set at another timing (for example, at the start of printing).

  Next, the amount of metal ink discharged to each pixel is determined based on the color ink discharge amount of each pixel calculated in S252 and the glossiness set in S253 (S254). As described above, the discharge amount of the metal ink is adjusted for each pixel so that the total amount of the discharge amount of the color ink and the discharge amount of the metal ink in each pixel is approximately the same. That is, a large amount of metal ink is ejected in pixels where the amount of color ink ejected is relatively small, and a small amount of metal ink is ejected in pixels where the amount of color ink ejected is relatively large. For example, let A be the amount of metal ink ejected at a pixel with a gradation value of [00] in the color layer (a pixel that does not eject color ink). In this case, the printer driver sets the discharge amount of the metal ink to 0.7A in the pixel having the gradation value [01] in the color layer (the pixel from which the small dot of color ink is discharged), and the gradation value in the color layer The discharge amount of the metal ink is determined for each pixel according to the discharge amount of the color ink, for example, the discharge amount of the metal ink in the pixel of [11] (the pixel from which the large dot of color ink is discharged) is 0.2A. The

  Further, the amount of metal ink ejected for each pixel is adjusted according to the set glossiness. For example, if the metal ink discharge amount is set to A ′ when the gloss level is set to “medium”, the metal ink discharge amount is set to 1.5 A ′ when the gloss level is set to “strong”, and the gloss level Is set to “weak”, the intensity of the glossiness of the printed image is adjusted by increasing / decreasing the metal ink discharge amount for each pixel, such as setting the metal ink discharge amount to 0.5 A ′.

  A table of metal ink discharge amount data corresponding to the pixel data of the color layer may be stored in the memory 63 in advance, and the metal ink discharge amount for each pixel may be determined according to the table data. Good.

  Thereafter, the printer driver performs rasterization processing (S255), control data is added to the pixel data, and the print data is transmitted to the printer 1.

  The printer 1 performs a printing operation according to the received print data. Specifically, the controller 60 of the printer 1 controls the transport unit 20 and the like according to the control data of the received print data, controls the head unit 40 according to the pixel data of the print data, and sets the color from each nozzle provided in the head 41. Ink and metal ink are ejected. When printing, metal ink dots are ejected first, and then color ink dots are ejected.

<Effects of Second Embodiment>
In the second embodiment, the surface of the image to be formed is adjusted by adjusting the ejection amount of the metal ink so that the total height of the color ink dots and the metal ink dots formed for each pixel becomes substantially equal. Make it flat. As a result, it is possible to form a high-quality metallic image in which uneven glossiness on the image surface is less noticeable. At this time, the glossiness of the entire image can be adjusted by changing the ejection amount of the metal ink in each pixel to increase or decrease the amount of metal particles present on the medium.

=== Third Embodiment ===
In each of the above-described embodiments, color ink dots or metal ink dots are directly ejected on the medium. On the other hand, in the third embodiment, a transparent clear ink (CL) is ejected onto the medium to form a flat clear layer. Then, by forming color ink dots or metal ink dots on the clear layer, an image having a flat surface is printed.

<Regarding Dot Formation in the Third Embodiment>
FIG. 13 is a diagram illustrating dot formation according to the third embodiment. When printing is actually performed, irregularities may be generated on the surface of the medium to be printed (not flat). FIG. 13A shows a state of a cross section of the image surface when an image is printed using a medium having unevenness on the surface. As shown in the figure, when unevenness is generated on the surface of the medium, the dots that land on the medium form the image surface according to the unevenness. As described in the above-described embodiment, when the amount of dots ejected for each pixel is adjusted to be approximately the same, the image surface formed by the dots landed on the concave portion of the medium has a low height. Thus, the height of the image surface formed by the dots landed on the convex portion of the medium becomes high. Further, due to the unevenness on the surface of the medium, the metal ink dots (white circles in the figure) may land out of the ideal landing position (pixels). As a result, the image surface is not flat and gloss unevenness is likely to occur.

  In such a case, it is very difficult to detect irregularities on the surface of the medium and adjust the ink discharge amount for each pixel corresponding to the irregular shape. Therefore, before discharging the metal ink and the color ink, the clear ink is discharged over the entire surface of the medium (the area where the image is formed) to form a clear layer. Then, by forming metal ink dots and color ink dots on the formed clear layer, the surface of the printed image is made flat. Note that the clear ink is a transparent ink generally called “clear ink” that does not contain or contains a small amount of color material.

  FIG. 13B shows a cross-sectional state of the image surface when an image is printed after the clear layer is formed. By forming the clear layer as shown in the figure, at least one of the metal ink and the color ink is ejected onto the flat surface (clear layer), so that the image is the same as in the above embodiments. The surface is also formed flat. In addition, since metal ink dots (color ink dots) land on the surface of the flat clear layer, the possibility of deviation from the ideal landing position (pixels) is low, and metal ink dots do not depend on the type or nature of the medium. It becomes easy to fix. That is, in the present embodiment, the clear layer levels the surface of the medium (flattenes) and also has a function as a base layer when forming an image.

  In consideration of the function as the underlayer, the underlayer can be formed using an ink other than the clear ink (for example, white ink). However, since the clear layer is formed of transparent clear ink, the clear layer itself can easily reflect light regularly, thereby preventing unauthorized copying.

<About printing devices and print processing>
The configuration of the printing apparatus used in the third embodiment is the same as that of the printer 1 except for the head unit. In the present embodiment, a CL nozzle row that discharges clear ink (CL) is provided in the head portion 41 (not shown). The configuration of the clear ink nozzle row (CL) is the same as that of the other nozzle rows (see FIG. 4). The arrangement of the clear ink nozzle row (CL) is arbitrary, but it is desirable that the clear ink nozzle row (CL) be arranged next to the metal ink nozzle row (Me) in FIG. 4 or outside the black ink nozzle row (K).

  The printing process is basically the same as in the second embodiment (FIGS. 11 and 12). However, in this embodiment, in addition to the print data for ejecting the color ink and the metal ink, data that ejects the clear ink over the entire print area is generated by the printer driver. As the data for ejecting clear ink, for example, data for forming large dots of clear ink on all the pixels in the print area is generated. By forming large dots of clear ink on all pixels, adjacent clear inks can easily join together, and the entire surface of the medium is leveled to form a flat clear layer (see FIG. 13B). If a clear layer having a flat surface as shown in FIG. 13B can be formed, it is not always necessary to discharge clear ink to all pixels, and clear ink is discharged to predetermined pixels. There may be. For example, pixel data that forms large dots of clear ink at intervals of one pixel may be generated.

<Modification>
When printing is performed using clear ink, clear ink may be used not only as a base for the image but also for coating the upper surface of the image. FIG. 14 is a diagram illustrating dot formation according to a modification of the third embodiment.
First, as in the third embodiment described above, clear ink is ejected onto the medium to form a first clear layer for leveling unevenness on the medium surface. Thereafter, metallic ink and / or color ink is ejected onto the first clear layer to form a metallic image. In the modification, a clear ink is further ejected thereon to form a second clear layer having a flat surface. Similar to the data for forming the first clear layer, the printer driver generates data for forming the second clear layer and causes the clear ink to be ejected to predetermined pixels.
By providing a second clear layer on the metallic image that is formed on the first clear layer and has a flat surface, it is possible to make regular reflection of light more easily.

<Effect of the third embodiment>
In the third embodiment, clear ink is ejected onto a medium to form a clear layer, and metal ink dots and clear ink dots are formed on the clear layer so that the height of each pixel is uniform. Even when the surface of the medium has irregularities, the irregularities are leveled by the clear layer, making it easier to print an image with a flat surface. As a result, it is possible to print an image with less gloss unevenness and difficult to perform unauthorized copying or the like regardless of the state of the medium. Further, by forming a clear ink layer on the formed image, it is possible to print an image having a higher glossiness.

=== Other Embodiments ===
Although the printer as one embodiment has been described, the above embodiment is for facilitating the understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About liquid ejection device>
In the above-described embodiment, a printing apparatus (inkjet printer) that forms an image has been described as an example of a liquid ejection apparatus, but is not limited thereto. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional molding machine, liquid vaporizer, organic EL manufacturing apparatus (especially polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technology as that of the present embodiment may be applied to various liquid ejection devices to which inkjet technology such as a device and a DNA chip manufacturing device is applied.

<Ink used>
In the above-described embodiment, an example of recording using four color inks of black (K), cyan (C), magenta (M), and yellow (Y) as the color ink has been described. It is not something that can be done. For example, recording may be performed using color inks other than KCMY, such as light cyan (LC), light magenta (LM), and white (W).
In addition, examples of inks containing silver particles or aluminum particles have been described as metal inks, but inks containing other particles such as copper and gold are used as long as they can reproduce the metallic luster at the time of printing. It is also possible.

<About piezo elements>
In the above-described embodiment, the piezo element PZT is exemplified as the element that performs the operation for discharging the liquid. However, other elements may be used. For example, a heating element or an electrostatic actuator may be used.

<About other printing devices>
In the above-described embodiment, the type of printer 1 that moves the head 41 together with the carriage has been described as an example. However, the printer may be a so-called line printer in which the head is fixed.

1 Printer 20 transport unit, 21 paper feed roller, 22 transport motor, 23 transport roller,
24 platen, 25 paper discharge roller,
30 Carriage unit, 31 Carriage, 32 Carriage motor,
40 head units, 41 heads, 411 case, 412 flow path unit,
412a flow path forming plate, 412b elastic plate, 412c nozzle plate,
412d pressure chamber, 412e nozzle communication port, 412f common ink chamber,
412g Ink supply path, 412h island part, 412i elastic film,
50 detector groups, 51 linear encoder, 52 rotary encoder,
53 Paper detection sensor, 54 Optical sensor,
60 controller, 61 interface, 62 CPU, 63 memory,
64 unit control circuit,
110 computer

Claims (7)

A head capable of ejecting ink;
A liquid ejection apparatus comprising: a control unit that controls ejection of the ink from the head to the printing medium;
The head is capable of discharging color ink and glitter ink,
When the control unit discharges the color ink and the glitter ink onto the printing medium, the control unit sets a time difference in the dischargeable timing to the same place with one ink and the other ink, and the same place Adjusting the discharge amount of the other ink in accordance with the discharge amount of the one ink to the surface so that the ink surface formed by the both inks is flattened on the printing medium after both inks are discharged. And a liquid ejecting apparatus for controlling both the inks. The liquid ejection device according to claim 1,
The control unit provides a time difference so that the dischargeable timing to the same place is set so that the discharge timing of the glittering ink precedes the discharge timing of the color ink. apparatus. The liquid ejection device according to claim 1 or 2,
The liquid ejection apparatus according to claim 1, wherein the total ejection amount of the two inks is substantially the same on the printing medium regardless of the ejection locations of the two inks. The liquid ejection device according to any one of claims 1 to 3,
The head can further discharge clear ink,
When the color ink and the glitter ink are ejected onto the printing medium, the controller controls to eject the clear ink after ejecting the liquid ink. The liquid ejection device according to claim 4,
The control unit performs control so that the clear ink is ejected onto the printing medium, at least one of the color ink and the glitter ink is ejected thereon, and further the clear ink is ejected thereon. A liquid ejection apparatus characterized by being a thing. A head capable of ejecting ink;
In a liquid ejection method of a liquid ejection apparatus, comprising: a control unit that controls ejection of the ink from the head to a printing medium.
A step of discharging one of color ink and glitter ink,
A step of corresponding to the discharge amount of either the color ink or the glitter ink, and discharging the other ink in accordance with the other ink non-discharge or the one discharge amount at the same discharge location;
A liquid discharge method comprising: In a printed matter on which an image using color ink and glitter ink on a printing medium is formed,
The printed matter, wherein the color ink and the glitter ink have laminated portions, and an image forming surface composed of the color ink and the glitter ink is substantially flat.

Images