JP2010179536A - Printing method and printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress image quality deterioration due to ink feathering. <P>SOLUTION: The printing method is performed by using: a first nozzle for ejecting color ink that is used for printing an image on a medium and is cured by irradiation with an electromagnetic wave; a second nozzle for ejecting process solution that is used for processing the surface of the medium and is cured by irradiation with an electromagnetic wave; and an irradiation part that emits the electromagnetic wave. The printing method includes: forming color dots on the medium by ejecting the color ink from the first nozzle, and printing the image constituted of the color dots on the medium and ejecting the process solution from the second nozzle so as not come in contact with the color dots and forming process dots in areas other than the image area on the medium; and irradiating the color dots and the process dots with the electromagnetic wave from the irradiation part before the color dots and the process dots formed on the medium come in contact with one another. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing method and a printing apparatus.

  2. Description of the Related Art Printing apparatuses that perform printing using ink (for example, UV ink) that is cured by irradiation with electromagnetic waves (for example, ultraviolet (UV)) are known. In such a printing apparatus, ink is ejected from a nozzle onto a medium (paper, film, etc.), and then an electromagnetic wave is irradiated onto dots formed on the medium. By doing so, the dots are cured and fixed to the medium, so that it is possible to perform good printing even on a medium that hardly absorbs liquid (for example, see Patent Document 1).

JP 2000-158793 A

When an image is printed with UV ink, glossiness differs between a region where the image is printed and a region where the image is not printed. Therefore, it is conceivable to form dots of colorless and transparent UV clear ink (a kind of processing liquid) in a region where an image is not printed so that the surface of the medium has a uniform gloss.
However, when dots of UV color ink for printing an image come into contact with dots of processing liquid such as clear ink, the image quality may be deteriorated due to ink bleeding. Similarly, even if dots of UV color ink for printing an image come into contact with dots of background ink such as white ink for printing a background, a problem of ink bleeding occurs.
An object of the present invention is to suppress deterioration in image quality due to ink bleeding.

A main invention for achieving the above object is a color ink for printing an image on a medium, the first nozzle for discharging the color ink that is cured when irradiated with electromagnetic waves, and the surface of the medium. A printing method using a second nozzle that discharges a processing liquid that is cured when irradiated with an electromagnetic wave, and an irradiation unit that irradiates the electromagnetic wave. By ejecting ink to form color dots on the medium, an image composed of the color dots is printed on the medium, and the processing liquid is ejected from the second nozzle without contacting the color dots. Then, forming processing dots in areas other than the image on the medium, and before the color dots formed on the medium and the processing dots contact, And irradiating the electromagnetic wave morphism unit to the color dot and the processing dots, a printing method having a.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

FIG. 2 is a block diagram illustrating a configuration of a printer. FIG. 3 is a schematic view around a print area. 3A and 3B are explanatory diagrams of the nozzle arrangement of each head. 4A to 4C are explanatory diagrams of the shape of the UV ink (dots) landed on the medium and the UV irradiation timing. It is explanatory drawing which shows the case where it prints only with color ink (1st comparative example). It is the schematic which shows the case where a clear dot is formed in the pixel which does not form a color dot (2nd comparative example). It is explanatory drawing of the formation position of the dot of this embodiment. It is explanatory drawing of the dot at the time of the main hardening of this embodiment. It is explanatory drawing which shows the case where clear ink is apply | coated to the whole surface after image formation. It is explanatory drawing which shows the case where clear ink is apply | coated to the whole surface after image formation. It is a schematic explanatory drawing of this embodiment. FIG. 6 is a flowchart of processing performed by a printer driver. It is a flowchart of the printing process by the printer 1 of this embodiment. It is the schematic of the printing area periphery of 2nd Embodiment. FIG. 15A to FIG. 15C are a schematic diagram around the print area and an explanatory diagram of a print operation according to the third embodiment. It is a perspective view of the serial printer of 4th Embodiment. It is explanatory drawing of the structure of the head 32 of 4th Embodiment. It is the schematic of the printing area periphery of 5th Embodiment. It is a flowchart of the printing process by the printer of 5th Embodiment.

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

A color ink for printing an image on a medium, which is a first nozzle that discharges color ink that is cured when irradiated with electromagnetic waves, and a processing liquid for processing the surface of the medium, which is irradiated with electromagnetic waves. Then, a printing method using a second nozzle that discharges a working fluid to be cured and an irradiation unit that irradiates the electromagnetic wave, wherein the color ink is discharged from the first nozzle to form a color dot on the medium. By forming, an image composed of color dots is printed on the medium, and the processing liquid is ejected from the second nozzle without being in contact with the color dots, and other than the image on the medium. Forming the processing dots in the region, and before the color dots formed on the medium and the processing dots come into contact with each other, Printing method having a method comprising irradiating the processing dots becomes apparent.
According to such a printing method, it is possible to suppress deterioration in image quality due to ink bleeding between the color dots and the processing dots.

In this printing method, before the color dots formed on the medium come into contact with the processing dots, the color dots and the processing are performed with an irradiation amount that temporarily cures the color dots and the processing dots. After the electromagnetic dots are irradiated with the electromagnetic waves, and the diameters of the color dots and the processing dots are expanded after the irradiation of the electromagnetic waves, the color dots and the processing dots are further brought into contact with each other. It is preferable to irradiate the dots with the electromagnetic waves.
According to such a printing method, since the dots are solidified after expanding the color dots and the processing dots, the gap between the color dots and the processing dots is reduced, and the gloss can be made more uniform. .

In this printing method, the time from when the color dots are formed to when the electromagnetic wave of the irradiation unit is irradiated, and after the formation of the processing dots, the electromagnetic wave of the irradiation unit is irradiated. It is desirable that the region is determined according to at least one of the time until.
According to such a printing method, it is possible to prevent the color dots and the processing dots from coming into contact when irradiating electromagnetic waves.

In this printing method, after the electromagnetic wave is applied to the color dots and the processing dots, the processing liquid is applied onto the color dots and the processing dots, and the color dots and the processing dots are applied. It is desirable that the electromagnetic wave is applied to the processing liquid applied on the dots.
According to such a printing method, the height difference of the surface can be reduced and the gloss can be improved.

In this printing method, in addition to the second nozzle, a third nozzle that discharges the processing liquid is provided, and the irradiation unit is disposed downstream of the third nozzle in the conveyance direction of the medium. May be provided with another irradiation section.
According to such a printing method, as the medium is transported in the transport direction, color dots are formed, processing dots are formed, electromagnetic waves are irradiated before the color dots contact the processing dots, color dots, and processing dots. The processing liquid can be applied in this order, and the applied processing liquid can be irradiated with an electromagnetic wave.

In this printing method, it is preferable that the first nozzles are arranged at a predetermined nozzle pitch, and the third nozzles are arranged at a nozzle pitch narrower than the predetermined nozzle pitch.
According to such a printing method, when applying the working fluid, dots can be formed at a high density, and the surface can be made uniform even if the surface of the medium is somewhat uneven.

Also, color ink for printing an image on a medium, which is a first nozzle that discharges color ink that cures when irradiated with electromagnetic waves, and a processing liquid for processing the surface of the medium, the electromagnetic waves being By forming a color dot on the medium by ejecting the color ink from the second nozzle that ejects the processing liquid that cures when irradiated, the irradiation unit that irradiates the electromagnetic wave, and the first nozzle. An image composed of the following is printed on the medium, and the processing liquid is ejected from the second nozzle without being in contact with the color dots, thereby forming processing dots in an area other than the image on the medium. In addition, before the color dots formed on the medium come into contact with the processing dots, the electromagnetic waves are transmitted from the irradiation unit to the color dots and the processing dots. And the controller to be irradiated to,
A printing apparatus having

Further, a color ink for printing an image on a medium, a first nozzle that discharges a color ink that is cured when irradiated with electromagnetic waves, and a background ink for printing the background of the image, A printing method using a second nozzle that discharges background ink that is cured when irradiated with an electromagnetic wave, and an irradiation unit that irradiates the electromagnetic wave, wherein the color ink is discharged from the first nozzle and the color ink is discharged. By forming color dots on the medium, an image composed of the color dots is printed on the medium, and the processing liquid is ejected from the second nozzle without contacting the color dots. Forming a background dot in a region other than the image, and before the color dot formed on the medium contacts the background dot, the electromagnetic wave of the irradiation unit Printing method having a method comprising irradiating the color dots and the background dots becomes apparent.
According to such a printing method, it is possible to suppress deterioration in image quality due to ink bleeding between color dots and background dots.

=== First Embodiment ===
In the first embodiment, a line printer (printer 1) will be described as an example of a printing apparatus.

<About printer configuration>
FIG. 1 is a block diagram of the overall configuration of the printer 1. FIG. 2 is a schematic view around the print area.

The printer 1 is a printing device that prints an image on a medium such as paper, cloth, or film, and is communicably connected to a computer 110 that is an external device.
A printer driver is installed in the computer 110. The printer driver is a program for displaying a user interface on a display device (not shown) 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. The printer driver can also be downloaded to the computer 110 via the Internet. In addition, this program is comprised from the code | cord | chord for implement | achieving various functions.
Then, the computer 110 outputs print data corresponding to the image to be printed to the printer 1 in order to cause the printer 1 to print an image.
The “printing apparatus” means an apparatus that prints an image on a medium, and corresponds to the printer 1, for example. The “printing control device” means a device that controls the printing device, and corresponds to, for example, the computer 110 in which a printer driver is installed.

  The printer 1 of the present embodiment is an apparatus that prints an image on a medium by ejecting ultraviolet curable ink (hereinafter referred to as UV ink) that is cured by irradiation with ultraviolet light (hereinafter referred to as UV) as an example of a liquid. The UV ink is an ink containing an ultraviolet curable resin, and is cured by undergoing a photopolymerization reaction in the ultraviolet curable resin when irradiated with UV. Note that the printer 1 of the present embodiment prints an image using four colors of CMYK UV ink (color ink) and colorless and transparent UV ink (clear ink).

  The printer 1 according to this embodiment includes a transport unit 20, a head unit 30, an irradiation unit 40, a detector group 50, and a controller 60. The printer 1 that has received print data from the computer 110 that is an external device controls each unit (the transport unit 20, the head unit 30, and the irradiation unit 40) by the controller 60, and prints an image on a medium according to the print data. The controller 60 controls each unit based on the print data received from the computer 110 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.

  The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined direction (hereinafter referred to as a transport direction). The transport unit 20 includes an upstream transport roller 23 </ b> A, a downstream transport roller 23 </ b> B, and a belt 24. When a transport motor (not shown) rotates, the upstream transport roller 23A and the downstream transport roller 23B rotate, and the belt 24 rotates. The medium fed by a paper feed roller (not shown) is conveyed by the belt 24 to a printable area (area facing the head). As the belt 24 transports the medium, the medium moves in the transport direction with respect to the head unit 30. The medium that has passed through the printable area is discharged to the outside by the belt 24. Note that the medium being transported is electrostatically attracted or vacuum attracted to the belt 24.

The head unit 30 is for ejecting UV ink onto a medium. In the present embodiment, a color ink for forming an image and a colorless and transparent clear ink are used as the UV ink. The head unit 30 discharges each ink to the medium being conveyed, thereby forming dots on the medium and printing an image on the medium. The printer 1 of the present embodiment is a line printer, and each head of the head unit 30 can form dots for the medium width at a time. As shown in FIG. 2, in order from the upstream side in the transport direction, a black ink head K that discharges black UV ink, a cyan ink head C that discharges cyan UV ink, and a magenta ink that discharges magenta UV ink. A head M, a yellow ink head Y that discharges yellow UV ink, a first clear ink head CL1 that discharges clear ink, and a second clear ink head CL2 are provided. Hereinafter, each color head that discharges color ink is also referred to as a color ink head, and each head that discharges clear ink is also referred to as a clear ink head. Of the clear ink heads, the first clear ink head CL1 is also simply referred to as the first head CL1, and the second clear ink head CL2 is also simply referred to as the second head CL2.
Details of the configuration of the head unit 30 will be described later.

  The irradiation unit 40 irradiates UV toward the UV ink that has landed on the medium. The dots formed on the medium are cured by receiving UV irradiation from the irradiation unit 40. The irradiation unit 40 of this embodiment includes a provisional curing irradiation unit 42 and a main curing irradiation unit 44.

The pre-curing irradiation unit 42 irradiates UV for pre-curing dots formed on the medium. In the present embodiment, the term “temporary curing” refers to curing performed to prevent bleeding between dots.
The provisional curing irradiation unit 42 is provided between the first head CL1 and the second head CL2 of the clear ink head. Further, the length in the medium width direction of the pre-curing irradiation unit 42 is equal to or larger than the medium width. Then, the pre-curing irradiation unit 42 irradiates the dots formed by the color ink head of the head unit 30 and the first head CL1 with UV.
The provisional curing irradiation unit 42 of the present embodiment includes a light emitting diode (LED) as a light source for UV irradiation. The LED can easily change the irradiation energy by controlling the magnitude of the input current.
The details of temporary curing will be described later.

The main curing irradiation unit 44 irradiates UV for main curing the dots formed on the medium. In the present embodiment, the main curing is curing performed to completely solidify the dots.
The main curing irradiation unit 44 is provided downstream of the second head CL2 in the transport direction. Further, the length of the main curing irradiation unit 44 in the medium width direction is equal to or greater than the medium width. The main curing irradiation unit 44 irradiates the dots formed by the heads of the head unit 30 with UV.
The main curing irradiation unit 44 of the present embodiment includes a lamp (a metal halide lamp, a mercury lamp, or the like) as a UV irradiation light source.
Details of the main curing will be described later.

  The detector group 50 includes a rotary encoder (not shown), a paper detection sensor (not shown), and the like. The rotary encoder detects the rotation amount of the upstream side conveyance roller 23A and the downstream side conveyance roller 23B. The transport amount of the medium can be detected based on the detection result of the rotary encoder. The paper detection sensor detects the position of the leading edge of the medium being fed.

  The controller 60 is a control unit (control unit) for controlling the printer. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. 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 unit for controlling the entire printer. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

<About printing operation>
When the printer 1 receives print data from the computer 110, the controller 60 first rotates a paper feed roller (not shown) by the transport unit 20 and sends a medium to be printed onto the belt 24. The medium is conveyed on the belt 24 without stopping at a constant speed, and passes under the head unit 30 and the irradiation unit 40. During this time, ink is intermittently ejected from the nozzles of each head of the head unit 30 to form dots on the medium, and UV is irradiated from each irradiation section of the irradiation unit 40. Thus, an image is printed on the medium. Finally, the controller 60 discharges the medium on which image printing has been completed.

<About the configuration of the head>
As shown in FIG. 2, the printer 1 of this embodiment has a color ink head and a clear ink head.
The color ink head ejects UV ink for printing an image for each ink color. In this embodiment, as a color ink head, a black ink head K, a cyan ink head C, a magenta ink head M, and a yellow ink head Y are provided in order from the upstream side in the transport direction. The color ink head is provided upstream of the clear ink head and each irradiation unit in the transport direction. The nozzle arrangement of the color ink head will be described later.

The first head CL1 for clear ink ejects colorless and transparent clear ink which is a kind of processing liquid for processing the surface of the medium. In the present embodiment, the first head CL1 discharges clear ink to a region other than the image. The first head CL <b> 1 is provided between the color ink head and the temporary curing irradiation unit 42. The nozzle arrangement of the first head CL1 will be described later.
The second head CL2 for clear ink ejects clear ink (hereinafter also referred to as application) over the entire surface of the medium. The second head CL <b> 2 is provided between the provisional curing irradiation unit 42 and the main curing irradiation unit 44. The nozzle arrangement of the second head CL2 will be described later.

3A and 3B are explanatory diagrams of the nozzle arrangement of each head.
FIG. 3A shows the arrangement of nozzles of the first head CL1 of the color ink head or the clear ink head. Each of these heads is provided with two nozzle rows of “A row” and “B row” as shown in the figure.
The nozzles in each row are arranged at an interval (nozzle pitch) of 1/180 inch along a direction (nozzle row direction) intersecting the transport direction. Further, the position in the nozzle row direction of the nozzles in the A row and the position in the nozzle row direction of the nozzles in the B row are shifted by a half nozzle pitch (1/360 inch). As a result, color dots or clear dots can be formed with a resolution of 1/360 inch.

FIG. 3B shows the arrangement of the nozzles of the second head CL2 for clear ink. The second head CL2 includes an upstream head CL2a and a downstream head CL2b. Each of the upstream head CL2a and the downstream head CL2b includes two nozzle rows, “A row” and “B row”, as in the color ink head or the clear ink first head CL1. Yes.
In the second head CL2, the position of the nozzle of the upstream head CL2a in the nozzle row direction and the position of the nozzle of the downstream head CL2b in the nozzle row direction are shifted by a quarter nozzle pitch (1/720 inch). . As a result, the second clear dot can be formed with a resolution of 1/720 inch. Thus, since the second head CL2 has twice as many nozzle rows as the respective heads for color ink or the first head CL1 for clear ink, it is possible to form dots with high density.

  The length of each nozzle row in the nozzle row direction is equal to or longer than the length corresponding to the medium width, whereby dots corresponding to the medium width can be formed at a time.

<About temporary curing and main curing>
4A to 4C are explanatory diagrams of the shape of the UV ink (dots) landed on the medium and the UV irradiation timing. Note that the irradiation timing is delayed in the order of FIGS. 4A, 4B, and 4C.
When UV is irradiated so as to stop the spread of dots immediately after dot formation, for example, FIG. 4A is obtained. In this case, bleeding can be suppressed, but the gloss is deteriorated because the irregularities on the surface of the medium constituted by the dots increase.
On the other hand, when the UV is irradiated for the first time after the dots have sufficiently spread, for example, as shown in FIG. 4C. In this case, the gloss is good. However, bleeding tends to occur between other inks.

In the printer 1 of the present embodiment, the irradiation unit 40 includes a provisional curing irradiation unit 42 and a main curing irradiation unit 44, and performs two-stage curing, that is, provisional curing and main curing after dot formation. Hereinafter, the function of each curing will be described.
The function of temporary curing is to prevent bleeding between dots. The amount of UV irradiation applied to the dots during the first temporary curing is small, and the UV ink (dots) continues to spread without being completely solidified even after the first temporary curing. However, after the temporary curing is performed, the problem of bleeding hardly occurs even if the dots come into contact with each other.
The function of the main curing is to completely solidify the ink. The UV irradiation amount for the main curing is larger than the UV irradiation amount for the temporary curing. That is, the irradiation amount of temporary curing <the irradiation amount of main curing.

<The subject of a comparative example and the outline of this embodiment>
(First comparative example)
FIG. 5 is an explanatory diagram illustrating a case where printing is performed using only color ink. In the following description, the dots formed by each color ink are also referred to as color dots.
When UV ink is used, the unevenness of the surface due to the dots is larger than that of normal water-based ink dots (for example, there are unevenness of elevation difference of about 5 to 10 μm). In the case of normal water-based ink, the unevenness of the paper is larger than the unevenness of the dots, so the surface unevenness due to the dots is not noticeable. On the other hand, in the case of UV ink, glossy unevenness occurs when printing is performed using only color ink, which deteriorates image quality (referred to as problem 1). Therefore, for such a problem 1, it is conceivable to form a dot (hereinafter, clear dot) with clear ink in a portion where no color dot is formed (an area other than an image).
Further, since the density of the image is expressed by the change in the dot density, the unevenness of the surface varies depending on the density of the image (referred to as problem 2). A thick portion in FIG. 5 indicates a dark portion of the image, and a thin portion indicates a light portion of the image. For such a problem 2, it can be considered that clear ink is applied to the entire surface after image formation.

(Second comparative example)
The second comparative example is a comparative example that copes with the problem 1 described above.
FIG. 6 is a schematic diagram illustrating a case where clear dots are formed on pixels in which color dots are not formed. Square squares in the figure indicate pixels on the medium. Circles indicate dots, hatched dots indicate color dots, and non-hatched dots indicate clear dots.
Usually, the dots are formed larger than the pixels on the medium as shown in FIG. This is because the filled image can be printed without a gap. In this comparative example, clear dots are formed in pixels where color dots are not formed.
However, in such a case, a bleeding problem occurs in a portion painted in black in the drawing (referred to as problem 3).

(Summary 1 of this embodiment)
FIG. 7 is an explanatory diagram of dot formation positions in the present embodiment. Also in FIG. 7 (and FIG. 8 to be described later), square boxes in the figure indicate pixels on the medium. Circles indicate dots, hatched dots indicate color dots, and non-hatched dots indicate clear dots.
In the present embodiment, in order to cope with the above-described problem 3 of the second comparative example, clear dots are formed so as not to come into contact with color dots during dot formation. For example, as shown in FIG. 7, clear dots are not formed in pixels adjacent to pixels forming color dots.
Although the dot diameter is expanded after the dot formation, in this embodiment, the color dots and the clear dots are not in contact with each other even before temporary curing. Thereby, it is possible to suppress bleeding while making the gloss uniform.

FIG. 8 is an explanatory diagram of dots at the time of main curing according to the present embodiment.
After temporary curing, even if the color dots and clear dots are expanded and contacted before the main curing, the ink is difficult to spread. That is, after the temporary curing, the problem of bleeding as shown in FIG. 6 does not occur even if the color dots and the clear dots come into contact with each other. Therefore, in this embodiment, the controller 60 adjusts the UV irradiation amount of the temporary curing so that the color dots and the clear dots are in contact with each other during this period (from the temporary curing to the main curing). Thus, by controlling the UV irradiation amount at the time of temporary curing, even if the color dots and the clear dots are in a non-contact state before the temporary curing, it is possible to bring them into a contact state at the time of main curing. Thereby, the gloss of the printed image can be made more uniform.

(Third comparative example)
The third comparative example is a comparative example that copes with the problem 2 described above.
9 and 10 are explanatory diagrams showing a case where clear ink is applied to the entire surface after image formation.
In FIG. 9, clear ink is applied to the entire surface after the image formation of FIG. Even if the clear ink is uniformly applied to the entire surface as shown in FIG. 9, if a large amount of clear ink is applied directly to the medium, the ink moves in the horizontal direction (surface direction), and ink aggregation occurs.
Therefore, as shown in FIG. 10, the clear ink aggregates in a region other than the image, and uniform gloss cannot be obtained (referred to as problem 4).

(Summary 2 of this embodiment)
FIG. 11 is a schematic explanatory diagram of this embodiment.
In this embodiment, in order to cope with the problem 4 of the third comparative example, clear dots are formed in a portion where no color dots are formed (an area other than an image). Thereafter, the color dots and the clear dots are temporarily cured, and after the temporary curing, clear ink is applied to the entire surface.
Thus, in this embodiment, since clear ink is apply | coated on the temporarily hardened ink, aggregation like FIG. 10 becomes difficult to produce. In this way, the height difference (unevenness) can be reduced by applying clear ink. Thereby, gloss can be made favorable.

<Regarding the Printing Process of the First Embodiment>
FIG. 12 is a flowchart of processing performed by the printer driver when the printer 1 performs printing.
The printer driver receives 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. When converting image data from an application program into print data, the printer driver performs resolution conversion processing, color conversion processing, halftone processing, contact dot detection processing, clear dot removal processing, rasterization processing, command addition processing, etc. . Various processes performed by the printer driver will be described below.

  The resolution conversion process is a process for converting image data (text data, image data, etc.) output from an application program into a resolution (print resolution) for printing on paper. 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. Note that each pixel data of the image data after the resolution conversion process is multi-gradation (for example, 256 gradations) RGB data represented by an RGB color space.

The color conversion process is a process for converting RGB data into data in a CMYKCl color space in which a Cl plane is added to the CMYK color space. Note that the image data in the CMYK color space is data corresponding to the ink color of the printer, and the image data on the Cl plane is data indicating that there is an image in an area where there is no image in the image data on the CMYK plane. . In other words, the printer driver generates data indicating that there is an image in an area where there is no image in the CMYK plane image data based on the RGB data. Further, the gradation value of the image data on the Cl plane is the average gradation value of the image data on the CMYK plane.
This color conversion processing is performed based on a table (color conversion lookup table LUT) in which gradation values of RGB data and gradation values of CMYK data are associated with each other. Note that the pixel data after the color conversion processing is CMYK data of 256 gradations represented by a CMYK color space.

  The halftone process is a process for converting high gradation number data into gradation number data that can be formed by a printer. For example, data representing 256 gradations is converted into 1-bit data representing 2 gradations or 2-bit data representing 4 gradations by halftone processing. In the halftone process, a dither method, a γ correction, an error diffusion method, or the like is used. The data subjected to the halftone process has a resolution equivalent to the print resolution (for example, 720 × 720 dpi). The image data after halftone processing corresponds to 1-bit or 2-bit pixel data for each pixel, and this pixel data is data indicating the dot formation status (presence / absence of dot, dot size) in each pixel. become. Of the image data in the CMYKCl color space after halftone processing, the image data on the Cl plane is data indicating the formation status of clear dots in each pixel.

The contact dot detection process is a process for detecting a clear dot in contact with a color dot using image data on the Cl plane. The method will be described below.
First, the printer driver determines the size of each color dot. In the present embodiment, the dot size differs for each color. This is because the time from dot formation to temporary curing is different. For example, in the case of FIG. 2, the time from when the dots are formed by the black head K to when the preliminary curing irradiation unit 42 performs the temporary curing is the time from the formation of the dots by the yellow head Y to the temporary curing irradiation unit 42. It becomes longer than the time until temporary curing is performed. That is, when ejecting the same amount of ink, the black ink has a longer spreading time and larger dots than the yellow ink.

Next, the printer driver determines the size of the clear dot. The size of the clear dot is determined based on the time from the dot formation to the temporary curing similarly to the size of the color dot.
Further, the printer driver detects the position of the clear dot adjacent to the color dot.
Then, the printer driver calculates the distance between the detected clear dot and the adjacent color dot, and determines contact / non-contact based on the calculated distance and the size of the color dot and the clear dot.

  The clear dot removal process is a process of removing clear dots that come into contact with color dots. In this clear dot removal process, the image data on the Cl plane is corrected so that clear dots that come into contact with the color dots are not formed. Specifically, pixel data indicating that a clear dot is to be formed is replaced with pixel data indicating that a dot is not formed.

  The rasterizing process rearranges the pixel data arranged in a matrix for each pixel data in 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.

The command addition process is a process for adding command data corresponding to the printing method to the rasterized data. The command data includes, for example, conveyance data indicating the medium conveyance speed.
The print data generated through these processes is transmitted to the printer 1 by the printer driver.

FIG. 13 is a flowchart of print processing by the printer 1 of this embodiment.
First, the controller 60 discharges the color ink from each head of the color ink head based on the print data during the conveyance of the medium, and forms color dots in the image formation area (S101). In this way, an image composed of color dots is printed.

  Next, the controller 60 causes the clear ink to be ejected to a region where no image is formed by the first head CL1 for clear ink. In this way, clear dots are formed in a region other than the image (S102). At this time, the color dots and the clear dots are not in contact (see FIG. 7). This is because when the print data is created by the printer driver, the above-described contact dot detection process and clear dot removal process are performed to remove the clear dots that are in contact with the color dots. As described above, in this embodiment, since color ink and clear ink are not brought into contact with each other when dots are formed, image bleeding as shown in FIG. 6 does not occur.

  Next, the controller 60 irradiates the UV with the pre-curing irradiation unit 42 to perform temporary curing of the color dots and the clear dots (S103). Even in this temporary curing, the color dots and the clear dots are not in contact. This is because, in the contact dot detection process of the printer driver, when detecting clear dots that come into contact with color dots, the size of the dots in temporary curing is taken into consideration. By this temporary curing, bleeding between dots is suppressed. Further, since the dot diameter is expanded even after temporary curing, the gloss can be improved. The controller 60 controls the amount of UV light for temporary curing so that the color dots and the clear dots are in contact with each other as shown in FIG.

  Then, after temporary curing, the controller 60 applies clear ink to the entire surface of the medium by the second head CL2 for clear ink (S104). As described above, the second head CL2 for clear ink has a larger number of nozzles than other heads. Thereby, even if there is some unevenness before application, the surface becomes uniform. In addition, since clear ink is applied on the color dots (and clear dots) that have already been temporarily cured, there is no problem of ink bleeding.

  At this time, the already pre-cured clear dots function like wedges, and the clear ink applied to the entire surface is less likely to move in the horizontal direction (surface direction) and is less likely to aggregate. Therefore, aggregation like FIG. 10 becomes difficult to occur. Thus, by applying clear ink over the entire surface, the height difference (unevenness) of the dots can be reduced. Thereby, gloss can be made favorable. Further, since the clear ink does not aggregate as shown in FIG. 10, the gloss can be made more uniform.

Thereafter, the controller 60 performs the main curing by irradiating UV with the main curing irradiation unit 44 (S105). In the main curing, UV is irradiated on the clear ink applied to the entire surface of the medium. By this main curing, each dot is completely solidified. At the time of the main curing, the color dots and the clear dots are in contact with each other as shown in FIG. This is because the controller 60 controls the UV irradiation amount of the pre-curing irradiation unit 42 so that the color dots and the clear dots come into contact with each other during the main curing.
Then, after the main curing, the medium is discharged.

(Summary of the first embodiment)
In this embodiment, an image composed of color dots is printed on a medium by forming color dots with a color ink head, and the first head CL1 for clear ink is used to print images other than images so as not to contact the color dots. Clear dots are formed in this area. And before a color dot and a clear dot contact, UV is irradiated to the colored dot and the clear dot by the irradiation part 42 for temporary curing. Thereby, it is possible to suppress deterioration in image quality due to ink bleeding while obtaining uniform gloss.

  Further, in the present embodiment, before the color dots and the clear dots are in contact with each other, provisional curing is performed with an irradiation amount capable of expanding the diameter of the dots by the provisional curing irradiation unit 42, and after the color dots and the clear dots are in contact with each other, The main curing is performed by the curing irradiation unit 44. Thus, since the dots are solidified after the dots are expanded, the gap between the color dots and the clear dots is reduced, and the gloss can be made more uniform. In addition, since temporary curing is performed before the color dots and the clear dots come into contact with each other, the problem of ink bleeding does not occur even if the color dots and the clear dots come into contact with each other.

  Further, in the present embodiment, the area for forming the clear dots is determined by the printer driver in consideration of the size of the color dots at the time of temporary curing and the size of the clear dots. Thereby, it can prevent a dot from contacting at the time of temporary hardening.

  In the present embodiment, after the color dots and the clear dots are temporarily cured, the clear ink is applied to the entire surface by the second clear head CL2. The clear ink applied by the main curing irradiation section 44 is irradiated with UV for main curing. Thereby, the height difference (unevenness | corrugation) of the surface can be made small, and glossiness can be made favorable.

  In this embodiment, the color ink head, the clear ink first head CL1, the temporary curing irradiation unit 42, the clear ink second head CL2, and the main curing irradiation unit are sequentially arranged from the upstream side in the transport direction. 44 is provided, the printing of the image, the formation of clear dots in areas other than the image, temporary curing, application of clear ink on the entire surface, and main curing can be performed in order as the medium is conveyed in the conveying direction. .

  The nozzle pitch of the second head CL2 is narrower than the nozzle pitch of the color ink head or the first head CL1. Thereby, when clear ink is applied to the entire surface, dots can be formed at a high density, and the surface can be made uniform even if the surface of the medium is somewhat uneven.

=== Second Embodiment ===
FIG. 14 is a schematic view of the periphery of the printing area of the second embodiment. Compared to the first embodiment (FIG. 2), a pre-curing irradiation section is provided behind each color ink head (downstream in the transport direction). In FIG. 14, parts having the same configuration as in FIG.
The irradiation unit 40 of the second embodiment includes provisional curing irradiation units 42 a to 42 e and a main curing irradiation unit 44.
The provisional curing irradiation units 42a to 42e are for irradiating UV for preventing bleeding between dots. However, after temporary curing, the dots are not completely solidified and continue to spread. The pre-curing irradiation sections 42a to 42e are provided on the downstream side in the transport direction of the black ink head K, cyan ink head C, magenta ink head M, yellow ink head Y, and first clear ink head CL1, respectively. That is, in the second embodiment, a provisional curing irradiation unit is provided for each ink color.
Similarly to the first embodiment, the pre-curing irradiation units 42a to 42e include LEDs as light sources for UV irradiation.
The main curing irradiation unit 44 is the same as that in the first embodiment.

<Printing Operation of Second Embodiment>
Next, the printing operation of the second embodiment will be described.
First, the controller 60 discharges black ink from the black ink head K when the medium passes under the black ink head K. Thereafter, UV is irradiated when the medium passes through the pre-curing irradiation section 42a, and the dots formed by the black ink head K are pre-cured. Dot formation and UV irradiation are similarly performed for cyan ink, magenta ink, and yellow ink.

In the second embodiment liquid, as described above, UV irradiation is performed from the corresponding provisional curing irradiation section immediately after the color dots of the color ink are formed for each color.
Then, the controller 60 causes clear dots to be formed in a region other than the image by the first head CL1 for clear ink. At this time, as in the first embodiment, the clear dots are formed so that the clear dots do not contact the color dots. And before a color dot and a clear dot contact, each dot is irradiated with UV by the irradiation part 42e for temporary hardening.
Thereafter, the clear ink is applied to the entire surface by the second head CL2, and the dots formed on the medium are irradiated with UV by the main-curing irradiation unit 44 to be main-cured.

  In the second embodiment, as in the first embodiment, the first head CL1 for clear ink forms dots as shown in FIG. In order to realize this, the printer driver of the second embodiment calculates the size of the dot at the time of temporary curing after the formation of the clear dot in the above-described “contact dot detection process”. In the second embodiment, when calculating the size of the color dots at the time of temporary curing after the clear dot formation, the printer driver E is not the time from the dot formation to the provisional curing, but after each color dot formation. The amount of UV irradiation at the time of temporary curing is also considered. For example, the larger the UV irradiation amount at the time of temporary curing after forming the color dots, the smaller the size of the color dots at the time of temporary curing after forming the clear dots.

In the second embodiment, the same effect as that of the first embodiment can be obtained.
Further, in the second embodiment, since temporary curing is performed immediately after each color dot is formed, the speed of the dot diameter expansion is slowed, so that the dot size can be easily calculated.

=== Third Embodiment ===
FIG. 15A to FIG. 15C are a schematic diagram around the print area and an explanatory diagram of a print operation according to the third embodiment. In these drawings, the same components as those in FIG. In the third embodiment, a head that discharges clear ink to a region other than an image and a head that applies clear ink to the entire surface are used together. Further, the irradiation unit that performs temporary curing and the irradiation unit that performs main curing are used in combination. In the printer 1 of the third embodiment, the medium can be transported (reverse transported) in the reverse direction of the transport direction by reversing the rotation of the upstream transport roller 23A and the downstream transport roller 23B. It has become.

<Differences in configuration between the third embodiment and the first embodiment>
In the third embodiment, the same second head CL2 as that in FIG. 2 is provided as a head for clear ink, and an irradiation unit 45 that combines temporary curing and main curing is provided as a UV irradiation unit.
The second head CL2 is provided downstream of the color ink head in the transport direction. As described above, the second head CL2 has the upstream head CL2a and the downstream head CL2b. The nozzle arrangement of each head is the same as in FIG. 3B. One of the upstream head CL2a and the downstream head CL2b is used both for forming clear dots in a region where no image is formed and for applying clear ink to the entire surface, as will be described later.
The irradiation unit 45 is provided downstream of the second head CL2 in the transport direction. The irradiation unit 45 includes, for example, an LED as a light source for UV irradiation, and can change the amount of UV irradiation as in the above-described embodiment. The irradiation unit 45 of the third embodiment performs both temporary curing and main curing by changing the irradiation amount.

<Operation at the time of printing in the third embodiment>
First, as shown in FIG. 15A, the controller 60 transports the medium in the transport direction, and sequentially ejects ink from each head for color ink when the medium passes under the head for color ink. Thereby, an image composed of color dots is printed on the medium.
In addition, when the medium passes under the second head CL2 for clear ink, the controller 60 ejects clear ink from one of the upstream head CL2a and the downstream head CL2b to form clear dots in a region other than the image. Let At this time, the clear dots are formed so as not to contact the color dots, as in the above-described embodiment.
Of the two heads, the upstream head CL2a and the downstream head CL2b, one head is not used. This is because the clear dots have the same resolution (360 dpi) as the color dots.

When the medium passes under the irradiation unit 45, the controller 60 causes the irradiation unit 45 to irradiate the pre-curing UV. In this temporary curing, the color dots and the clear dots are not in contact with each other as in the above-described embodiment. That is, the pre-curing UV is irradiated before the color dots and the clear dots come into contact with each other. Further, the amount of irradiation of the temporary curing is controlled by the controller 60 so that the color dots and the clear dots are in contact with each other during the main curing described later.
After the temporary curing, as shown in FIG. 15B, the controller 60 reverses the rotation of the upstream transport roller 23A and the downstream transport roller 23B to transport the medium in the direction opposite to the transport direction (reverse transport). By this reverse conveyance, the medium is conveyed to the front (upstream side in the conveyance direction) of the second head CL2 for clear ink.

  Then, as shown in FIG. 15C, the controller 60 reverses the rotation of the upstream side conveyance roller 23A and the downstream side conveyance roller 23B again to convey the medium in the normal conveyance direction. Then, when the medium passes under the second head CL2, clear ink is ejected from the second head CL2, and the clear ink is applied to the entire surface of the medium. At this time, all the nozzles (see FIG. 3B) of the two heads of the second head CL2 for clear ink are used. As described above, in the third embodiment, when applying clear ink to the entire surface, two heads (upstream head CL2a and downstream head CL2b) can be used, so dot formation (application) on the entire surface of the medium is possible. It can be done quickly. In this case, since the reverse conveyance is performed, only the entire surface is applied to the medium on the belt 24. Therefore, in 3rd Embodiment, the conveyance speed in the case of whole surface application | coating can be made quick.

  Then, when the medium passes under the irradiation unit 45, the controller 60 causes the irradiation unit 45 to emit UV for main curing.

  In addition, when the reverse conveyance is performed in this manner, the accuracy of the position of the medium is deteriorated, and an error may occur in the dot formation position. However, since the clear ink is applied to the entire surface of the medium after reverse conveyance, even if an error occurs in the clear dot formation position, the image quality is not affected.

Also in the third embodiment, the same effect as in the first embodiment can be obtained.
Further, in the third embodiment, by carrying the reverse, the clear ink head and the UV irradiation unit can be used as one each. Therefore, the number of components around the head of the printer 1 is reduced compared to the first embodiment. it can. Further, as described above, the conveyance speed during the entire surface application can be increased, and the time required for the entire surface application can be shortened.

=== Fourth Embodiment ===
In the fourth embodiment, the above-described embodiment is an embodiment of a line printer. In the fourth embodiment, the head moves while moving the medium in the direction of movement (moving direction) intersecting the direction of conveyance and the head. The same processing is performed for a printer (serial printer) that alternately performs dot forming operations for ejecting ink from the printer. In the serial printer of the fourth embodiment, as will be described later, nozzle rows that discharge clear ink are provided on both sides (outside) of a plurality of color ink nozzle rows. Further, the serial printer of the fourth embodiment can perform reverse conveyance as will be described later.

FIG. 16 is a perspective view of the serial printer according to the fourth embodiment.
The serial printer shown in FIG. 16 includes a carriage 11, a head 32, and a provisional curing irradiation unit 43.
The carriage 11 is for moving the head 32 in the moving direction. Further, the carriage 11 detachably holds a cartridge that stores UV ink. The carriage 11 reciprocates in the movement direction along the guide shaft by a carriage motor (not shown).
The head 32 is provided on the carriage 11. The head 32 ejects UV ink from each nozzle of the head while moving in the moving direction as the carriage 11 moves. Details of the head 32 will be described later.
The provisional curing irradiation unit 43 is provided over a length equal to or larger than the medium width on the downstream side in the transport direction from the printing region (that is, the head 32). The temporary curing irradiation unit 43 includes an LED as a light source for UV irradiation.

<Regarding Configuration of Head of Fourth Embodiment>
FIG. 17 is an explanatory diagram of a configuration of the head 32 according to the fourth embodiment. As shown in FIG. 17, the black ink nozzle row K, the cyan ink nozzle row C, the magenta ink nozzle row M, and the yellow ink nozzle row Y are moved on the lower surface of the head 32 as nozzle rows for color ink. They are formed in order from one end side to the other end side in the direction.
Further, a clear ink nozzle row is provided on both sides of the color ink nozzle row. Specifically, a first clear ink nozzle row CL1 ′ is provided on one end side in the movement direction from the black ink nozzle row K, and a second clear ink is provided on the other end side in the movement direction from the yellow ink nozzle row Y. A nozzle row CL2 ′ is provided. Each nozzle row is provided with a plurality (for example, 180) of nozzles that discharge UV ink at a predetermined nozzle pitch.

<Operation at the time of printing in the fourth embodiment>
Next, an operation during printing according to the fourth embodiment will be described. Note that the subject of the following operations is the controller of the printer of the fourth embodiment.
In the first dot forming operation, UV ink is ejected from the color ink nozzles of the head 32 while moving the carriage 11 from one end of the moving direction to the other end (hereinafter also referred to as the forward path), and is composed of color dots. Print the image on the media.
Further, during this forward dot forming operation, the clear ink is ejected from the first clear ink nozzle row CL1 ′ on the upstream side of the movement of the head 32 in the clear ink nozzle row and cleared to a region other than the image. Form dots. Note that, as in the above-described embodiment, the clear dots are ejected so as not to contact the color dots.
Thereafter, the medium is transported in the transport direction by a predetermined amount (transport operation).

In the next dot forming operation, UV ink is ejected from the color ink nozzles of the head 32 while moving the carriage 11 from the other end in the moving direction to one end (hereinafter also referred to as a return path), and the color dots are configured. The image to be printed is printed on the medium.
In addition, during the dot forming operation in the backward path, clear ink is ejected from the second clear ink nozzle array CL2 ′ on the upstream side of the movement of the head 32 among the clear ink nozzle arrays and cleared to an area other than the image. Form dots. At this time, the clear dots are ejected so as not to contact the color dots.
In this way, the nozzle rows used to form clear dots are switched in the forward path and the backward path.

  Thereafter, the carrying operation and the dot forming operation are repeated. Then, when the medium is transported below the provisional curing irradiation unit 43, the provisional curing UV is irradiated from the provisional curing irradiation unit 43. In this case as well, the color dots and the clear dots are not in contact with each other as in the above-described embodiment. That is, pre-curing UV is irradiated before the color dots and the clear dots come into contact. In addition, the irradiation amount of temporary hardening is adjusted so that a color dot and a clear dot may contact before main hardening.

  Thereafter, the medium is reversely conveyed upstream in the conveyance direction. By this reverse conveyance, the medium is conveyed to a position on the upstream side in the conveyance direction with respect to the printing area (that is, the head 32). Then, the transport operation for transporting the medium again in the transport direction and the dot forming operation are repeated. In this case, the dot forming operation is to apply clear ink to the entire surface of the medium, and the color ink nozzle rows are not used, but two clear ink nozzle rows at both ends thereof are used. In other words, two clear ink nozzle arrays are used together in the forward and backward dot forming operations. Since two nozzle rows can be used in this way, the dot formation operation time can be shortened.

  Thereafter, before the medium is discharged, the medium is irradiated with UV for main curing by an irradiation unit (not shown) for main curing. As in the third embodiment, the provisional curing irradiation unit 43 may perform both provisional curing and main curing UV irradiation.

  As described above, also in the case of the fourth embodiment, the formation of clear ink and UV irradiation similar to those of the first embodiment can be performed, and the same effects as those of the first embodiment can be obtained.

=== Fifth Embodiment ===
In the above-described embodiment, the clear dots are formed by the clear ink in the area other than the image. However, in the fifth embodiment, the background ink (the white ink in this embodiment) is used for the background in the area other than the image. Dots are formed.

FIG. 18 is a schematic view of the periphery of a printing area according to the fifth embodiment. In FIG. 18, the same components as those in FIG.
As shown in FIG. 18, the printer of the fifth embodiment includes a white ink head W1 for forming white ink dots, instead of the clear ink first head CL1 shown in FIG. Note that the fifth embodiment also includes the second head CL2 for clear ink shown in FIG.
White ink is for printing the background of an image. For example, simply printing characters on a transparent film makes it difficult to see the characters without a background color. As described above, simply printing an image on a transparent medium makes it difficult to see the image. In such a case, it is necessary to use background ink such as white ink.

Other configurations are almost the same as those of the first embodiment. Also, the printer driver processing is almost the same as in the first embodiment. However, in the fifth embodiment, in the processing of the printer driver, the Cl plane of the first embodiment becomes the W plane.
In the fifth embodiment, white dots (corresponding to background dots) by white ink are formed in the portions where the clear dots were formed by the first head CL1 in the first embodiment.

FIG. 19 is a flowchart of the printing process performed by the printer 1 according to the fifth embodiment.
First, the controller 60 discharges color ink from each head of the color ink heads according to the conveyance of the medium, and forms color dots in the image formation region with the color ink (S201). In this way, an image composed of color dots is printed.
Next, the controller 60 causes the white ink head W1 to discharge the white ink to the area where the image is not formed with the color ink. Thus, white dots are formed in a region other than the image (S202). At this time, the color dots and the white dots are not in contact (see FIG. 7). This is because when the print data is created by the printer driver, the above-described contact dot detection process and clear dot removal process are performed to remove the white dots that are in contact with the color dots. As described above, in this embodiment, since color ink and white ink are not brought into contact with each other when dots are formed, image bleeding as shown in FIG. 6 does not occur.

  Next, the controller 60 causes the provisional curing irradiation unit 42 to irradiate UV, and performs provisional curing of color dots and white dots (S203). Even during this pre-curing UV irradiation, the color dots and the white dots are not in contact. This is because, in the contact dot detection process of the printer driver, when detecting clear dots that come into contact with color dots, the size of the dots in temporary curing is taken into consideration. By this temporary curing, bleeding between dots is suppressed. Further, since the dot diameter is expanded even after temporary curing, the gloss can be improved. The controller 60 controls the irradiation amount of the temporary curing so that the color dots and the white dots are in contact with each other as shown in FIG.

  Then, after temporary curing, the controller 60 applies clear ink to the entire surface of the medium by the second head CL2 for clear ink (S204). As described above, the second head CL2 for clear ink has a larger number of nozzles than other heads. Thereby, even if there is some unevenness before application, the surface becomes uniform. In addition, since the clear ink is applied on the color dots (and white dots) that have already been temporarily cured, there is no problem of ink bleeding.

  At this time, the already pre-cured white dots function like wedges, and the clear ink applied to the entire surface is less likely to move in the horizontal direction and is less likely to aggregate. Therefore, aggregation like FIG. 10 becomes difficult to occur. Thus, by applying clear ink to the entire surface, the height difference (unevenness) can be reduced. Thereby, gloss can be made favorable. Further, since the clear ink does not aggregate as shown in FIG. 10, the gloss can be made more uniform.

  After that, the controller 60 performs the main curing by irradiating the UV with the main curing irradiation unit 44 (S205). In the main curing, UV is irradiated onto the clear ink applied to the entire surface of the medium. By this main curing, each dot is completely solidified. At the time of the main curing, the color dots and the white dots are in contact with each other as shown in FIG. This is because the controller 60 controls the UV irradiation amount of the provisional curing irradiation unit 42 so that the color dots and the white dots come into contact with each other during the main curing.

  Then, after the main curing is performed, the medium is discharged.

<Difference between Print Processing and Trapping Processing of Fifth Embodiment>
The trapping process is a print target image and a background image, and when the print target image portion is printed with a plain background image, for example, the print target image is slightly expanded. And processing so as to overlap the background image.
When the trapping process is not performed, for example, when the overlapping position is slightly shifted due to expansion / contraction of the medium, a portion that is neither the print target image nor the background image (for example, a solid portion) is visible at the boundary between the print target image and the background image. It will be. In this case, the completed image may be unsightly. When the trapping process is performed, such a problem does not occur even if the overlapping positions are slightly shifted.

However, if the trapping process is performed in the configuration of the present embodiment, the color dots constituting the image to be printed and the background dots (white dots) constituting the background image overlap, so that the color dots and white dots Bleeding occurs.
On the other hand, in this embodiment, since the color dots and the white dots are not brought into contact without performing the trapping process, bleeding does not occur between the color dots and the white dots. Although the trapping process is not performed in the present embodiment, the problem that the portion that is neither the print target image nor the background image is visible at the boundary between the print target image and the background image as described above hardly occurs. This is because, as shown in FIG. 8, the diameters of the color dots and white dots (background dots) are expanded before the main curing.

  As described above, in the fifth embodiment, the color ink is formed on the medium by forming the color dots with the color ink head, and the white ink head W1 is used so as not to contact the color dots. Thus, white dots are formed in a region other than the image. Then, before the color dots and the white dots come into contact with each other, the pre-curing irradiation unit 42 irradiates the colored dots and the white dots with UV. Thereby, it is possible to suppress deterioration in image quality due to ink bleeding while obtaining uniform gloss.

  In the fifth embodiment, before the color dots and the white dots are in contact with each other, the provisional curing is performed with an irradiation amount that can expand the diameter of the dots by the provisional curing irradiation unit 42, and after the color dots and the white dots are in contact with each other, The main curing is performed by the main curing irradiation unit 44. Accordingly, since the dots can be widened without causing bleeding between the dots, the gloss can be made more uniform.

=== Other Embodiments ===
Although a printer or the like 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 the printer>
In the above-described embodiment, a printer has been described as an example of an apparatus, but the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporizer, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technology as that of the present embodiment may be applied to various printing apparatuses to which ink jet technology is applied, such as an apparatus and a DNA chip manufacturing apparatus.

<About ink>
In the above-described embodiment, ink (UV ink) that is cured by being irradiated with ultraviolet rays (UV) is ejected from the nozzles. However, the liquid ejected from the nozzle is not limited to such an ink, and a liquid that is cured by being irradiated with an electromagnetic wave other than UV (for example, visible light) may be ejected from the nozzle. In this case, electromagnetic waves (such as visible light) for curing the liquid may be irradiated from the temporary curing irradiation unit and the main curing irradiation unit.

<Applying clear ink to the entire surface>
In the embodiment described above, the clear ink is applied to the entire surface, but it is not always necessary to apply the clear ink to the entire surface. Even with such a configuration, if dots are formed as shown in FIG. 7, the effect of preventing bleeding can be obtained.

<About the realization method of FIG. 7>
The process for realizing the state of FIG. 7 is not limited to the method described in the first embodiment.
For example, the printer driver may perform color conversion into a normal CMYK color space when performing color conversion processing. Then, a region where no dot is formed is specified in the image data of the CMYK color space after the halftone process, and the Cl plane image data is generated so that the clear dots are arranged as shown in FIG. .

<About the printer driver>
The printer driver processing in FIG. 12 may be performed on the printer side. In that case, a printing apparatus is configured by the printer and the PC on which the printer driver is installed.

<About clear ink 1>
In the embodiment described above, the colorless and transparent clear ink is used to form dots other than the image. However, the present invention is not limited to the clear ink. For example, it may be a translucent processing liquid that gives the surface of the medium gloss. Further, the processing does not have to be glossy. A working fluid that adjusts the texture of the surface of the medium may be used.

<About clear ink 2>
In the embodiment described above, the clear dots are formed after the color dots are formed, but the present invention is not limited to this. For example, the color dots may be formed after the clear dots are formed, or the clear dots and the color dots may be formed at the same time.

<About white ink>
In the fifth embodiment, white ink is used to form background dots, but the present invention is not limited to white ink. For example, if the medium is cream, the same cream-colored ink as the medium may be used as the background ink.

<About the state after temporary curing>
In the embodiment described above, the color dots and the clear dots are in contact with each other after temporary curing (before the main curing) as shown in FIG. 8, but the color dots and the clear dots may not be in contact with each other after the temporary curing. Even in such a case, an effect of suppressing deterioration of image quality due to ink bleeding can be obtained.

DESCRIPTION OF SYMBOLS 1 Printer, 11 Carriage, 20 Conveyance unit, 23A Upstream conveyance roller, 23B Downstream conveyance roller, 24 Belt, 30 Head unit, 32 Head, 40 Irradiation unit, 42, 42a-42e, 43 Temporary curing irradiation part, 44 Main curing irradiation unit, 45 irradiation unit, 50 detector group, 60 controller, 61 interface unit, 62 CPU, 63 memory, 64 unit control circuit, 110 computer, K black ink head, C cyan ink head, M magenta ink head , Y Yellow ink head, CL1 first clear ink head, CL2 second clear ink head, CL2a upstream head, CL2b downstream head, W1 white ink head

Claims (8)

A color ink for printing an image on a medium, the first nozzle discharging a color ink which is cured when irradiated with electromagnetic waves;
A processing liquid for processing the surface of the medium, the second nozzle discharging a processing liquid that hardens when irradiated with electromagnetic waves;
An irradiation unit for irradiating the electromagnetic wave;
A printing method using
By ejecting the color ink from the first nozzle to form color dots on the medium, an image composed of the color dots is printed on the medium, and the second without contacting the color dots. Discharging the processing liquid from a nozzle to form processing dots in a region other than the image on the medium;
Irradiating the color dots and the processing dots with the electromagnetic wave of the irradiation unit before the color dots formed on the medium and the processing dots come into contact;
A printing method comprising: The printing method according to claim 1, comprising:
Irradiate the electromagnetic wave to the color dots and the processing dots with an irradiation amount that temporarily cures the color dots and the processing dots before the color dots formed on the medium come into contact with the processing dots. And
After the color dots and the processing dots come into contact with each other by expanding the diameters of the color dots and the processing dots after the irradiation of the electromagnetic waves, the color dots and the processing dots are further irradiated with the electromagnetic waves. Printing method. The printing method according to claim 1 or 2,
At least one of the time from the formation of the color dot to the irradiation of the electromagnetic wave of the irradiation unit and the time from the formation of the processing dot to the irradiation of the electromagnetic wave of the irradiation unit The printing method in which the area is determined accordingly. The printing method according to any one of claims 1 to 3,
After the electromagnetic wave is applied to the color dots and the processing dots, the processing liquid is applied onto the color dots and the processing dots, and then applied onto the color dots and the processing dots. A printing method in which the processing solution is irradiated with the electromagnetic wave. The printing method according to claim 4, wherein
In addition to the second nozzle, a third nozzle for discharging the machining liquid is provided,
A printing method, wherein an irradiation unit different from the irradiation unit is provided downstream of the third nozzle in the medium conveyance direction. The printing method according to claim 5, wherein
The first nozzles are arranged at a predetermined nozzle pitch,
The third nozzles are arranged at a nozzle pitch narrower than the predetermined nozzle pitch.
Printing method. A color ink for printing an image on a medium, the first nozzle discharging a color ink which is cured when irradiated with electromagnetic waves;
A processing liquid for processing the surface of the medium, the second nozzle discharging a processing liquid that hardens when irradiated with electromagnetic waves;
An irradiation unit for irradiating the electromagnetic wave;
By ejecting the color ink from the first nozzle to form color dots on the medium, an image composed of the color dots is printed on the medium, and the second without contacting the color dots. Before discharging the processing liquid from a nozzle to form processing dots in a region other than the image on the medium, and before the color dots formed on the medium and the processing dots come into contact, A controller that irradiates the color dots and the processing dots with the electromagnetic waves from the irradiation unit;
A printing apparatus. A color ink for printing an image on a medium, the first nozzle discharging a color ink which is cured when irradiated with electromagnetic waves;
A background nozzle for printing the background of the image, the second nozzle discharging the background ink that is cured when irradiated with electromagnetic waves;
An irradiation unit for irradiating the electromagnetic wave;
A printing method using
By ejecting the color ink from the first nozzle to form color dots on the medium, an image composed of the color dots is printed on the medium, and the second without contacting the color dots. Discharging the processing liquid from a nozzle to form a background dot in a region other than the image on the medium;
Irradiating the color dots and the background dots with the electromagnetic waves of the irradiation unit before the color dots formed on the medium and the background dots contact with each other;
A printing method comprising:

Images