JP5765393B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection apparatus.

  There is known a liquid ejecting apparatus that performs printing using a liquid (for example, UV ink) that is cured by irradiation with an electromagnetic wave (for example, ultraviolet (UV)). In such a liquid ejecting apparatus, after ejecting a liquid from a nozzle onto a medium, the dots formed on the medium are irradiated with electromagnetic waves. 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 dots are formed with UV ink, if an electromagnetic wave is irradiated immediately after dot formation, bleeding between other inks can be prevented. However, after the ink has landed on the medium, if the ink is cured before the dots spread, the dot area will decrease, the print density will decrease, and the irregularity of the medium surface constituted by the dots will increase. There is a risk that the gloss may deteriorate.
On the other hand, if the electromagnetic waves are applied after the ink has landed on the medium after the dots have spread sufficiently, bleeding may occur between other inks even if the image density and image gloss are obtained. .
As described above, when ink that is cured by irradiation with electromagnetic waves is used, there is a conflict between suppressing ink bleeding and obtaining gloss and density of an image, and obtaining good image quality has been a problem. .
An object of the present invention is to obtain good image quality when an ink that is cured by irradiation with electromagnetic waves is used.

A main invention for achieving the above object is that a plurality of nozzles that discharge a liquid that cures when irradiated with electromagnetic waves are arranged in a first direction, and the liquid that has landed on a medium can be irradiated with the electromagnetic waves. The first irradiation unit, the second irradiation unit, and the third irradiation unit, and the nozzle row, the first irradiation unit, the second irradiation unit, and the third irradiation unit are moved in a second direction that intersects the first direction. And the first irradiation unit is opposed to a region where at least one of the plurality of nozzles of the nozzle array is opposed when the carriage unit moves in the second direction. disposed possible position, the third illumination unit, the disposed between the second irradiation unit and the Oite the first irradiation portion in a first direction, does not irradiate the electromagnetic wave from the third irradiating unit In the state, the first irradiation unit is illuminated. It is possible to irradiate the electromagnetic wave greater than the dose of the electromagnetic wave from the second irradiation unit to a liquid ejecting apparatus.
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. 2 is a schematic view around a printer head. 3A and 3B are cross-sectional views of the printer. It is explanatory drawing of a structure of a head. 5A to 5C are explanatory diagrams of the shape of the UV ink (dots) landed on the medium and the UV irradiation timing. FIG. 6A to FIG. 6D are explanatory diagrams of the state of image formation according to the first embodiment. It is explanatory drawing of the head part of 2nd Embodiment. 8A to 8E are explanatory diagrams of the dot forming operation of the second embodiment. It is explanatory drawing of the head part of 3rd Embodiment. It is explanatory drawing of the head part of 4th Embodiment. It is explanatory drawing of the printing operation of 4th Embodiment. 12A to 12E are explanatory diagrams of dot formation and UV irradiation conditions in the region a of FIG. It is explanatory drawing of the head part of 5th Embodiment.

=== Summary of disclosure ===
At least the following matters will become clear from the description of the present specification and the accompanying drawings.
(A) a carriage for moving in a moving direction a nozzle that discharges a liquid that is cured by irradiation with electromagnetic waves;
(B) a first irradiation unit that is provided on the carriage and irradiates the electromagnetic wave to dots formed by landing the liquid ejected from the moving nozzle on a medium;
(C) a second irradiation unit that is provided on the carriage and that irradiates the electromagnetic waves to the dots irradiated with the electromagnetic waves from the first irradiation unit, wherein the first irradiation unit has an irradiation amount of the electromagnetic waves A different second irradiation part;
A liquid ejection apparatus having the above becomes clear.
According to such a liquid ejecting apparatus, good image quality can be obtained when ink that is cured by irradiation with electromagnetic waves is used.

In this liquid ejection apparatus, it is preferable that the irradiation amount of the second irradiation unit is larger than the irradiation amount of the first irradiation unit.
According to such a liquid ejecting apparatus, it is possible to achieve both suppression of bleeding and gloss.

In this liquid ejection apparatus, it is preferable that the increase in the diameter of the dot that has progressed after the irradiation of the electromagnetic wave by the first irradiation unit is suppressed by the irradiation of the electromagnetic wave by the second irradiation unit.
According to such a liquid ejection apparatus, it is possible to easily control the dot diameter.

In this liquid ejection apparatus, the medium is transported in a transport direction intersecting the movement direction while the nozzle is reciprocated in the movement direction, and the liquid lands on the medium by the second irradiation unit. You may provide in the downstream of the said conveyance direction rather than the liquid landing area | region.
According to such a liquid ejection apparatus, it is possible to secure time until the dots are irradiated with the electromagnetic waves from the second irradiation unit.

In the liquid ejection apparatus, the first irradiation unit may be configured such that the irradiation amount of the upstream region in the transport direction and the downstream region in the transport direction of the irradiation unit that irradiates the electromagnetic wave are different. And it is preferable to comprise the said 2nd irradiation part.
According to such a liquid discharge apparatus, power saving can be achieved.

In such a liquid ejection device, there may be a region where the electromagnetic wave of the certain irradiation unit is not irradiated between the first irradiation unit and the second irradiation unit.
According to such a liquid ejecting apparatus, it is possible to secure a longer time until the dots are irradiated with the electromagnetic wave by the second irradiation unit. This makes it possible to control the dot diameter.

In this liquid ejection apparatus, the second irradiation unit may be provided at a position aligned with the first irradiation unit in the movement direction of the nozzle.
According to such a liquid ejecting apparatus, the electromagnetic wave is irradiated from the second irradiation unit following the irradiation of the electromagnetic wave of the first irradiation unit. Therefore, it is effective when it is not desired to spread the dots.

In the following embodiments, an ink jet printer (hereinafter also referred to as a printer 1) will be described as an example of the liquid ejection device.
=== First Embodiment ===
<About printer configuration>
Hereinafter, the printer 1 of the present embodiment will be described with reference to FIGS. 1, 2, 3 </ b> A, and 3 </ b> B. FIG. 1 is a block diagram illustrating a configuration of the printer 1. FIG. 2 is a schematic view around the head of the printer 1. 3A and 3B are cross-sectional views of the printer 1. 3A corresponds to the AA cross section of FIG. 2, and FIG. 3B corresponds to the BB cross section of FIG.

  The printer 1 of the present embodiment ejects 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 toward a medium such as paper, cloth, or film sheet. Thus, the apparatus prints an image on a medium. 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 this embodiment prints an image using four colors of CMYK UV ink.

  The printer 1 includes a transport unit 10, a carriage 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 10, the carriage unit 20, the head unit 30, and the irradiation unit 40) by the controller 60. 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 10 is for transporting a medium (for example, paper) in a predetermined direction (hereinafter referred to as a transport direction). The transport unit 10 includes a paper feed roller 11, a transport motor (not shown), a transport roller 13, a platen 14, and a paper discharge roller 15. The paper feed roller 11 is a roller for feeding the medium inserted into the paper insertion slot into the printer. The transport roller 13 is a roller that transports the medium fed by the paper feed roller 11 to a printable area, and is driven by a transport motor. The platen 14 supports the medium being printed. The paper discharge roller 15 is a roller for discharging the medium to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area.

  The carriage unit 20 is for moving (also referred to as “scanning”) the head in a predetermined direction (hereinafter referred to as a moving direction). The carriage unit 20 includes a carriage 21 and a carriage motor (not shown). The carriage 21 detachably holds an ink cartridge that stores UV ink. The carriage 21 is reciprocated along the guide shaft 24 by a carriage motor while being supported by a guide shaft 24 that intersects a conveyance direction described later.

The head unit 30 is for ejecting liquid (UV ink in this embodiment) onto a medium. The head unit 30 includes a head 31 having a plurality of nozzles. Since the head 31 is provided on the carriage 21, when the carriage 21 moves in the movement direction, the head 31 also moves in the movement direction. Then, when the head 31 is intermittently ejected while moving in the moving direction, dot lines (raster lines) along the moving direction are formed on the medium. In the following, the path moving from one end side to the other end side in FIG. 2 is referred to as the forward path, and the path moving from the other end side to the one end side is referred to as the return path. In the present embodiment, UV ink is ejected during both the forward and return periods. That is, the printer 1 of the present embodiment performs bidirectional printing.
The configuration of the head 31 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 the present embodiment includes first temporary curing irradiation units 42 a and 42 b, a second temporary curing irradiation unit 43, and a main curing irradiation unit 44. The first temporary curing irradiation units 42a and 42b correspond to the first irradiation unit, and the second temporary curing irradiation unit 43 corresponds to the second irradiation unit. The first temporary curing irradiation units 42 a and 42 b and the second temporary curing irradiation unit 43 are provided in the carriage 21.

  The first temporary curing irradiation portions 42a and 42b are provided on one end side and the other end side in the moving direction of the head 31 so as to sandwich the head 31, respectively. That is, the first temporary curing irradiation parts 42 a and 42 b are provided at positions aligned with the head 31 in the moving direction. Further, the length in the transport direction of the first temporary curing irradiation portions 42 a and 42 b is substantially the same as the length of the nozzle row of the head 31. Then, the first temporary curing irradiation units 42a and 42b move with the head 31 to irradiate the dots formed on the medium with UV. The first temporary curing irradiation units 42a and 42b of the present embodiment include light emitting diodes (LEDs) as light sources for UV irradiation. The LED can easily change the irradiation energy by controlling the magnitude of the input current.

The second pre-curing irradiation unit 43 is provided downstream of the head 31 in the transport direction at the center in the movement direction of the carriage 21. That is, the second temporary curing irradiation unit 43 is provided on the downstream side in the transport direction from the head 31 and the first temporary curing irradiation units 42a and 42b. In other words, the second pre-curing irradiation unit 43 is provided on the downstream side in the transport direction from the printing area (corresponding to the liquid landing area) where ink is landed on the medium and dots are formed.
The length of the second temporary curing irradiation unit 43 in the transport direction is also substantially the same as the length of the nozzle row of the head 31. The second pre-curing irradiation unit 43 moves with the head 31 when the head 31 moves, and irradiates the dots formed on the medium with UV. The second temporary curing irradiation unit 43 of the present embodiment includes an LED as a light source for UV irradiation.

  The main curing irradiation section 44 is provided downstream of the carriage 21 in the transport direction. That is, the main curing irradiation unit 44 is provided on the downstream side in the transport direction with respect to the first temporary curing irradiation units 42 a and 42 b and the second temporary curing irradiation unit 43. Further, the length in the moving direction of the main curing irradiation unit 44 is longer than the width of the medium to be printed. Then, the main curing irradiation unit 44 irradiates UV onto the medium conveyed under the main curing irradiation unit 44 by the conveying operation to cure the dots on the medium (main curing described later). 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 first temporary curing, the second temporary curing, and the main curing will be described later.

  The detector group 50 includes a linear encoder (not shown), a rotary encoder (not shown), a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder detects the position of the carriage 21 in the moving direction. The rotary encoder detects the rotation amount of the transport roller 13. The paper detection sensor 53 detects the position of the leading edge of the paper being fed. The optical sensor 54 detects the presence or absence of paper by a light emitting unit and a light receiving unit attached to the carriage 21. The optical sensor 54 can detect the position of the edge of the paper while being moved by the carriage 21, and can detect the width of the paper. The optical sensor 54 also detects the leading end (the end on the downstream side in the transport direction, also referred to as the upper end) and the rear end (the end on the upstream side in the transport direction, also referred to as the lower end) depending on the situation. it can.

  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. 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 1. 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.

  When printing, the controller 60 alternately repeats a dot forming operation for ejecting UV ink from the head 31 moving in the forward direction and the backward direction and a transport operation for transporting paper in the transport direction, as will be described later. An image composed of a plurality of dots is printed on paper. Hereinafter, the dot forming operation is referred to as “pass”. The n-th pass is called a pass n. In the pass, first temporary curing and second temporary curing are also performed as described later.

<About the configuration of the head 31>
FIG. 4 is an explanatory diagram of an example of the configuration of the head 31. As shown in FIG. 4, a black ink nozzle group K, a cyan ink nozzle row C, a magenta ink nozzle row M, and a yellow ink nozzle row Y are formed on the lower surface of the head 31. Each nozzle row includes a plurality of nozzles (180 in the present embodiment) that are ejection openings for ejecting each color of UV ink.

  The plurality of nozzles in each nozzle row are aligned at a constant interval (nozzle pitch: k · D) along the transport direction. Here, D is the minimum dot pitch in the carrying direction (that is, the interval at the highest resolution of dots formed on the medium). K is an integer of 1 or more. For example, when the nozzle pitch is 180 dpi (1/180 inch) and the dot pitch in the transport direction is 720 dpi (1/720 inch), k = 4.

  The nozzles in each nozzle row are assigned a lower number toward the downstream side in the transport direction. Each nozzle is provided with a piezo element (not shown) as a drive element for discharging UV ink from each nozzle. By driving this piezo element with a drive signal, droplet-like UV ink is ejected from each nozzle. The discharged UV ink lands on the medium and forms dots.

<About temporary curing and main curing>
5A to 5C 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. 5A, 5B, and 5C.
When UV is irradiated so as to stop the spread of dots immediately after dot formation, for example, FIG. 5A 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. Alternatively, the dot area is reduced, the printing density is lowered, and it is necessary to use a large amount of ink to obtain an image having a predetermined density.

On the other hand, when UV is irradiated for the first time after the dots are sufficiently spread, for example, as shown in FIG. 5C. In this case, the gloss is good. Or, the print density image becomes darker. However, bleeding tends to occur between other inks.
Therefore, the printer 1 of the present embodiment includes the first temporary curing irradiation units 42a and 42b, the second temporary curing irradiation unit 43, and the main curing irradiation unit 44 as the irradiation unit 40, and after dot formation, Three stages of curing are performed: first temporary curing, second temporary curing, and main curing. Hereinafter, the function of each curing will be described.

  The function of the first temporary curing is to prevent bleeding between dots. However, the amount of UV irradiation applied to the dots during the first temporary curing is small, and the UV ink (dots) continues to spread even after the first temporary curing.

The function of the second temporary curing is to stop the spread of dots. The irradiation amount for the second temporary curing is larger than the irradiation amount for the first temporary curing. The irradiation amount (mJ / cm ² ) is a product of irradiation energy (mW / cm ² ) and irradiation time (sec).

  In this embodiment, in order to change the irradiation amount of the first temporary curing and the second temporary curing, the input current of the LED of each irradiation unit is changed. However, the present invention is not limited to this. For example, the distance between the LED and the medium may be changed. For example, the irradiation time may be adjusted by changing the length of the LED in the moving direction.

The function of the main curing is to completely solidify the ink. The UV irradiation amount of the main curing is larger than the UV irradiation amount in the first temporary curing and the second temporary curing. That is,
The irradiation amount of the first temporary curing <the irradiation amount of the second temporary curing <the irradiation amount of the main curing.

As described above, in the present embodiment, the temporary curing is performed twice (first temporary curing and second temporary curing). Hereinafter, this reason will be described.
It is assumed that the total irradiation amount corresponding to the first temporary curing and the second temporary curing is irradiated at one time by one temporary curing irradiation unit. At this time, when the timing of temporary curing is determined, the size of the dot is determined by the size at the time of temporary curing (when UV is irradiated from the irradiation unit for temporary curing). For this reason, when the timing of temporary hardening is decided, the magnitude | size of a dot cannot be controlled. Even if the timing of temporary curing can be controlled, the spreading speed of dots during temporary curing is fast. For this reason, it is difficult to control the dot size at the irradiation timing.

  When two provisional curing irradiation units (first provisional curing irradiation unit and second provisional curing irradiation unit) are provided as in the present embodiment, bleeding can be prevented by the first preliminary curing. Even after the first temporary curing, the dots continue to spread. However, the spreading speed is slower than in the case where the first temporary curing is not performed.

  Next, in this embodiment, the spread of dots is stopped by the second temporary curing. When the timing of the second temporary curing is determined, the irradiation amount of the first temporary curing is controlled so that a desired dot size is obtained during the second temporary curing. Thus, the dot size can be controlled. In addition, when the timing of the second pre-curing can be changed, the dot spreading speed is slowed down in the first pre-curing, so the dots of a desired size can be obtained by controlling the timing of the second pre-curing. Is easy.

<Printing Operation of First Embodiment>
Next, the printing operation of the first embodiment will be described.
FIG. 6A to FIG. 6D are explanatory diagrams of the state of image formation according to the first embodiment.
6A and 6B show dot formation in the forward path, and FIGS. 6C and 6D show dot formation in the backward path. In addition, in each figure, the part used (it performs UV irradiation) among 1st temporary curing irradiation parts 42a and 42b and 2nd temporary curing irradiation part 43 is shown with the oblique line.

  First, as shown in FIG. 6A, in the first pass (outward path), the controller 60 discharges UV ink from the nozzles of the head 31 while moving the carriage 21 in the movement direction (outward direction). In addition, the controller 60 discharges ink from the head 31, and then the first temporary curing irradiation unit on the upstream side in the direction in which the head 31 moves (in this case, the first temporary curing irradiation unit that is shaded). The first temporary curing is performed by irradiating UV from 42a). In the present embodiment, since the first temporary curing irradiation portions 42a and 42b are provided at positions aligned with the head 31 of the carriage 21 in the moving direction, UV irradiation for the first temporary curing is performed immediately after dot formation. be able to. As described above, the first temporary curing is performed immediately after the dot formation, thereby preventing bleeding between the dots.

  With this forward path, an image is printed on the medium as shown in FIG. 6B. The printed image is in a state after the first temporary curing (a state in which bleeding is suppressed but dots continue to spread).

  After the forward path, the controller 60 conveys the medium by a predetermined amount (conveying operation). In the present embodiment, the transport amount is substantially the same as the length of the nozzle row, and as a result of this transport operation, as shown in FIG. 6, the print image by the pass of FIG. 6B is transported in the print area by the pass of FIG. Located immediately adjacent downstream in the direction.

  After the transport operation, the controller 60 causes the next pass (return path) to be performed. As shown in FIG. 6C, the controller 60 discharges UV ink from the nozzles of the head 31 while moving the carriage 21 in the movement direction (return path direction). In addition, the controller 60 discharges ink from the head 31, and then the first temporary curing irradiation unit on the upstream side in the direction in which the head 31 moves (in this case, the first temporary curing irradiation unit that is shaded). The first temporary curing is performed by irradiating UV from 42b). In FIG. 6C, since the moving direction is reverse to that in FIG. 6A, the first temporary effect irradiation unit used for the first temporary curing is reverse to that in FIG. 6A.

  By this pass, an image is printed on the medium as shown in FIG. 6D, and the first temporary curing is performed immediately after the formation of the dots of the image. In addition, it is possible to prevent bleeding between dots by performing the first temporary curing immediately after the dot formation.

  In this pass, the controller 60 causes the dots formed in the previous pass (outward path) to be irradiated with UV by the second temporary curing irradiation unit 43 that moves in the moving direction together with the head 31. Since the second pre-curing irradiation unit 43 is provided downstream of the head 31 of the carriage 21 in the transport direction, it can irradiate the dots formed in the previous pass with UV. As described above, in the first embodiment, the second temporary curing is performed in a pass subsequent to a pass in which dots are formed. By performing the second temporary curing at this timing, it is possible to stop the spreading of the dots while spreading the dots to some extent. That is, it is possible to secure time for spreading the dots. Since the first temporary curing is performed immediately after the dot formation, the spreading speed of the dots is slowed, thereby making it easy to control the spreading. Note that if the second temporary curing is performed immediately after the dot formation, the dots do not spread (see FIG. 5A), so that the unevenness of the surface of the medium constituted by the dots increases and the gloss deteriorates.

The image of the print area shown in FIG. 6D after the return pass is in a state after the first temporary curing (a state in which bleeding is suppressed but dots continue to spread), and the print area is conveyed. The printed image on the downstream side in the direction is in a state after the second temporary curing (a state in which the spread of dots has stopped).
Thereafter, similarly, the controller 60 repeatedly performs the pass and the transport operation alternately. Thereby, an image is printed on the medium.

  In addition, the controller 60 causes the main curing irradiation unit 44 to perform UV irradiation on the dots on the medium while printing is being continued or during paper discharge (main curing). This is because the dots are fixed by the second temporary curing, so that the main curing may be performed at a remote location.

  As described above, in the printer 1 of the present embodiment, the first temporary curing is performed by the first temporary curing irradiation units 42a and 42b with a small irradiation amount, and then the first temporary curing irradiation unit 43 performs the first. The second temporary curing is performed with a larger dose than the temporary curing. As a result, it is possible to achieve both suppression of ink bleeding and obtaining gloss and density of an image, and good image quality can be obtained.

Further, since the second pre-curing irradiation unit 43 is provided on the carriage 21 so as to be downstream in the transport direction from the printing region, the time from performing the first pre-curing to performing the second pre-curing. In consideration of the fact that the dots spread slightly during this time, the first temporary curing and the second temporary curing are performed so that the dots are finally fixed at a desired size by the second temporary curing. Irradiation conditions are set.
=== Second Embodiment ===
<About printer configuration>
FIG. 7 is an explanatory diagram of the head portion of the second embodiment. Compared with the first embodiment, the position of the second temporary curing irradiation section is different.
In the second embodiment, the carriage 21 is provided with first temporary curing irradiation units 42a and 42b and second temporary curing irradiation units 43a and 43b.

The first temporary curing irradiation parts 42a and 42b are respectively provided on one end side and the other end side in the moving direction of the head 31, as in the first embodiment.
The second pre-curing irradiation unit 43a is provided on the outer side (one end side in the moving direction) than the first pre-curing irradiation unit 42a. Further, the second pre-curing irradiation unit 43b is provided on the outer side (the other end side in the movement direction) than the first pre-curing irradiation unit 42b. As described above, the second pre-curing irradiation units 43 a and 43 b are provided at positions aligned in the moving direction of the first pre-curing irradiation units 42 a and 42 b and the head 31.
In addition, the length of the nozzle row of the head 31, the first temporary curing irradiation units 42a and 42b, and the second temporary curing irradiation units 43a and 43b in the transport direction is substantially the same.

Also in the second embodiment, the UV irradiation amount of the second temporary curing irradiation units 43a and 43b is larger than the UV irradiation amount of the first temporary curing irradiation units 42a and 42b. This is because the functions of the first temporary curing and the second temporary curing are different as described in the first embodiment.
The positions of the second pre-curing irradiation portions 43a and 43b may be adjustable in the movement direction by a guide (not shown) on the carriage 21. By doing so, the distance between the first temporary curing irradiation unit 42a (42b) and the second temporary curing irradiation unit 43c (43d) can be adjusted, and the timing of the second temporary curing can be adjusted. Thereby, the size of the dot can be adjusted.

<Printing Operation of Second Embodiment>
Next, the printing operation of the second embodiment will be described.
8A to 8E are explanatory diagrams of the dot forming operation of the second embodiment. In the figure, only dot formation in the forward path is shown.

  First, the controller 60 moves the carriage 21 in the movement direction (forward direction) as shown in FIG. 8A in the forward path. In the figure, the first pre-curing irradiation section and the second pre-curing irradiation section to be used are indicated by oblique lines. As shown in the figure, the pre-curing irradiation section (first pre-curing irradiation section 42a, second pre-curing irradiation section 43a) on the upstream side in the moving direction of the head 31 is used.

In FIG. 8B, the controller 60 in which the nozzle row of the head 31 is located on the medium causes ink (UV ink) to be ejected from each nozzle of the head 31. Thereby, UV ink is landed on the medium and dots are formed. Further, the controller 60 moves the carriage 21 in the movement direction. Since the first pre-curing irradiation part 42a is located on the upstream side in the moving direction of the head 31, as shown in FIG. 8C, the first pre-curing irradiation is performed on the dots immediately after being formed in FIG. 8B. Part 42a passes. At this time, the controller 60 irradiates the first temporary curing UV from the first temporary curing irradiation unit 42a. In this way, by performing the first temporary curing at the timing immediately after the dot formation, it is possible to prevent bleeding between the dots immediately after being formed on the medium.

  Also in FIG. 8B, the controller 60 discharges UV ink from the nozzles of the head 31. Therefore, as shown in FIG. 8C, the region facing the head 31 is in a state immediately after the dots are formed (not temporarily cured), and the region facing the first temporary curing irradiation unit 42a is the first. 1 It is in a state after temporary curing (a state in which bleeding is suppressed but dots continue to spread).

  Further, the controller 60 moves the carriage 21 in the movement direction. Since the second pre-curing irradiation unit 43a is located on the downstream side in the moving direction of the first pre-curing irradiation unit 42a, as shown in FIG. 8D, the region over the first pre-cured region in FIG. 8C. The second pre-curing irradiation part 43a passes. At this time, the controller 60 irradiates the second temporary curing UV from the second preliminary curing irradiation unit 43a. As can be seen, the timing of the second temporary curing is determined by the distance between the first temporary curing irradiation unit 42a and the second preliminary curing irradiation unit 43a. For this reason, according to timing, you may enable it to adjust the position of the irradiation part 43a for 2nd temporary hardening as mentioned above. For example, as the distance between the second pre-curing irradiation unit 43a and the first pre-curing irradiation unit 42a is increased, the timing of the second pre-curing can be delayed and the spread of the dots can be increased.

  Also in FIG. 8D, the controller 60 ejects UV ink from the nozzles of the head 31 and irradiates the first temporary curing UV from the first temporary curing irradiation unit 42a. Thus, in FIG. 8D, the region immediately opposite to the head 31 is in a state immediately after the dots are formed (not temporarily cured), and the region temporarily opposing the first temporary curing irradiation unit 42a is the first temporary region. It is in a state after curing (a state in which bleeding is suppressed but dots continue to spread), and in a region facing the second pre-curing irradiation portion 43a, a state after second pre-curing (dot spreading) Stopped state).

  Thereafter, the controller 60 similarly moves the carriage 21, discharges UV ink from the nozzle row of the head 31, performs the first temporary curing UV irradiation from the first temporary curing irradiation unit 42 a, and performs the second irradiation. The pre-curing irradiation unit 43a performs UV irradiation for the second pre-curing.

Then, as shown in FIG. 8E, when the carriage 21 passes through the medium, the dots formed on the medium are in a state after the second temporary curing.
Also in the case of a return trip, the controller 60 performs the same processing. It should be noted that the direction of movement on the return path is different from the case of the outbound path (reverse). Therefore, on the return path, the controller 60 uses the first temporary curing irradiation unit 42b and the second temporary curing irradiation unit 43b located on the upstream side in the moving direction of the head 31 on the return path, respectively, for the first temporary curing and the second temporary curing, respectively. Allow to cure.

  As described above, in the second embodiment, after the first temporary curing is performed by the first temporary curing irradiation unit 42a (42b), the second temporary curing is performed by the second preliminary curing irradiation unit 43a (43b). Yes. Accordingly, it is possible to achieve both suppression of ink bleeding and obtaining gloss of an image.

In the second embodiment, the second pre-curing irradiation units 43 a and 43 b are provided outside the first pre-curing irradiation units 42 a and 42 b on the carriage 21, respectively. Thereby, in the pass, after performing the first temporary curing, the second temporary curing can be subsequently performed. In other words, it is effective when you do not want to spread the dots too much. The time until the second temporary curing (that is, the spread of dots) can be adjusted by changing the distance between the second preliminary curing irradiation units 43a and 43b and the first temporary curing irradiation units 42a and 42b. .
=== Third Embodiment ===
FIG. 9 is an explanatory diagram of the head portion of the third embodiment. In the third embodiment, the configuration of the head is different from that of the second embodiment.
In the third embodiment, the carriage 21 includes four heads (heads 31a, 31b, 31c, and 31d). Similarly to the second embodiment, the carriage 21 includes first temporary curing irradiation units 42a and 42b and second preliminary curing irradiation units 43a and 43b.

  The head 31a and the head 31c are arranged side by side in the transport direction on the other end side in the movement direction. The head 31b and the head 31d are arranged side by side in the transport direction on one end side in the movement direction. The heads are arranged so as to be shifted in the transport direction.

The first pre-curing irradiation units 42a and 42b are provided outside the respective heads so as to sandwich the four heads.
Further, the second pre-curing irradiation units 43a and 43b are provided on the outer sides of the first pre-curing irradiation units 42a and 42b, respectively.
The lengths in the transport direction of the first temporary curing irradiation units 42a and 42b and the second temporary curing irradiation units 43a and 43b are the same as the length of the nozzle row composed of four heads.

Since the printing operation (dot formation and UV irradiation) according to the third embodiment is the same as that of the second embodiment, the description thereof is omitted.
Also in the third embodiment, after the first temporary curing is performed by the first temporary curing irradiation unit 42a (42b), the second temporary curing is performed by the second preliminary curing irradiation unit 43a (43b). Accordingly, it is possible to achieve both suppression of ink bleeding and obtaining gloss of an image.
=== Fourth Embodiment ===
<About printer configuration>
FIG. 10 is an explanatory diagram of the head portion of the fourth embodiment. Compared with the first and second embodiments, the position and shape of the second pre-curing irradiation section are different.
As shown in FIG. 10, in the fourth embodiment, second temporary curing irradiation units 43 c and 43 d are provided on the downstream side in the transport direction of the first temporary curing irradiation units 42 a and 42 b of the carriage 21, respectively. .
The length of the second pre-curing irradiation units 43c and 43d in the transport direction is the same as the length of the first pre-curing irradiation units 42a and 42b in the transport direction (the length of the nozzle row of the head 31). . However, if the transport amount of the medium is determined in advance, the length may be the same as the transport amount. For example, if the transport amount is 1/4 of the nozzle row length, the lengths of the second temporary curing irradiation units 43c and 43d may be 1/4 of the nozzle row length.
The UV irradiation amount of the second temporary curing irradiation units 42a and 42b is larger than the UV irradiation amount of the first temporary curing irradiation units 42a and 42b. This is because, as described above, the first temporary curing and the second temporary curing have different functions.

<Printing Operation of Fourth Embodiment>
FIG. 11 is an explanatory diagram of the printing operation of the fourth embodiment of the present embodiment. In the fourth embodiment, for convenience of explanation, the dot forming operation is performed only in the forward path, not in bidirectional printing. FIG. 11 shows the positions of the heads (nozzle rows), the first temporary curing irradiation unit 42a, and the second preliminary curing irradiation unit 43c in pass 1 to pass 3, and how dots are formed.
In FIG. 11, for simplification of description, only one nozzle row of a plurality of nozzle rows is shown, and the number of nozzles in the nozzle row is eight.

The left side of the drawing shows the position of the head (nozzle row) in pass 1 to pass 3. The nozzles indicated by black circles in the figure are nozzles that can eject ink. On the other hand, nozzles indicated by white circles are nozzles that cannot eject ink. For convenience of explanation, the head (nozzle row) is depicted as moving with respect to the paper, but the paper is actually moved (conveyed) in the transport direction.
Also, the right side of the figure shows the dots formed on the paper by the pass. A dot indicated by a black circle is a dot formed in the last pass, and a dot indicated by a white circle is a dot formed in a previous pass. That is, in this figure, white circles are dots formed in pass 1 or pass 2, and black circles are dots formed in pass 3.

  In this reference example, interlaced printing is performed. “Interlaced printing” means a printing method in which k is 2 or more and raster lines that are not formed are sandwiched between raster lines formed in one pass. For example, in FIG. 11, one raster line is sandwiched between raster lines formed in one pass. That is, k = 2 in this case.

  In interlace printing, each time the paper is transported by a constant transport amount F in the transport direction, each nozzle forms a raster line immediately above the raster line formed in the immediately preceding pass. Thus, in order to perform printing with a constant carry amount, (1) the number N of nozzles capable of ejecting ink is an integer of k and (2) the carry amount F is N · The condition is that it is set to D.

In the figure, the nozzle row has eight nozzles arranged along the transport direction. Since the nozzle pitch k of the nozzle row is 2, in order to satisfy the condition “N and k are relatively prime” for performing interlaced printing, all the nozzles are not used and seven nozzles (nozzles # 1 to # 1) are used. In addition, since seven nozzles are used, the paper is transported at a transport amount of 7 · D, and as a result, using a nozzle row having a nozzle pitch of 180 dpi (2 · D), 360 dpi ( = D), the dots are formed on the paper with an actual number of nozzles (180) greater than 7, so the actual transport amount (179 · D) is greater than 7 · D. Become more.

In the case of interlaced printing, k passes are required to complete a raster line having a continuous nozzle pitch width. For example, two passes are required to complete two raster lines that are continuous at a dot interval of 360 dpi using a nozzle row having a nozzle pitch of 180 dpi.
As will be described later, in FIG. 11, the hatched portion of the second pre-curing irradiation unit 43c indicates a region where the LED is turned on, and the unhatched portion indicates a region where the LED is turned off.

12A to 12E are explanatory diagrams of dot formation and UV irradiation conditions in the region a of FIG.
FIG. 12A is a diagram showing a dot formation operation (pass 2) in the region a. FIG. 12B is a diagram illustrating temporary curing (first temporary curing) in pass 2. FIG. 12C is a diagram illustrating a dot formation operation (pass 3) in the region a. FIG. 12D is a diagram illustrating temporary curing (first temporary curing) in pass 3. FIG. 12E is a diagram showing temporary curing (second temporary curing) in pass 4.

  First, as shown in 12A, in pass 2, the region a faces the nozzles on the upstream side of the head 31 (# 5 to # 7 nozzles). Then, UV ink is ejected from each nozzle to form dots on the medium.

  Thereafter, as the carriage 21 (head 31) moves in the moving direction, as shown in FIG. 12B, the first pre-curing irradiation unit located at the position aligned with the upstream nozzles (# 5 to # 7 nozzles) in the moving direction. 42a passes over area a. At this time, the controller 60 irradiates the medium from the first provisional curing irradiation unit 42a toward the medium. Thereby, the 1st temporary hardening of the dot formed by the upstream nozzle is performed. This temporary curing suppresses bleeding between dots, but the dots continue to spread. However, the speed of this spread is slowing down.

  Thereafter, the transport operation is performed, and in the next pass (pass 3), the region a faces the downstream nozzles (# 1 to # 4 nozzles) in the nozzle row as shown in FIG. 12C. Then, UV ink is ejected from each nozzle to form dots. At this time, dots are formed between the dots formed in pass 2. For example, in pass 2, a dot is formed by the # 3 nozzle in pass 3 between the dot formed by the # 7 nozzle and the dot formed by the # 6 nozzle. That is, at this time, in the region a, the dots immediately after formation (dots that have not been temporarily cured) and the dots that have been temporarily cured (first temporarily cured) are mixed.

  Thereafter, when the carriage 21 (head 31) moves in the moving direction, the first temporary curing irradiation unit 42a located in a position aligned with the downstream nozzles (# 1 to # 4 nozzles) moves over the region a. Pass through. At this time, the controller 60 irradiates the medium from the first provisional curing irradiation unit 42a toward the medium. As a result, both the dots immediately after the formation of the region a and the temporarily hardened dots (dots formed in pass 2) are both UV-irradiated and first temporarily hardened. In this case as well, bleeding between dots is suppressed, but the dots continue to spread.

  Thereafter, a transport operation is performed, and in the next pass (pass 4), the upstream region of the second pre-curing irradiation unit 43c passes over the region a. At this time, the controller 60 turns on the LED in the region upstream in the transport direction of the second pre-curing irradiation unit 43c (hatched portion in the drawing), whereby the dots in the region a are second pre-cured. The spread of dots is stopped by the second temporary curing. That is, the dot shape is fixed. At this time, the LED is extinguished in the region (the unhatched portion in FIG. 11) on the downstream side in the transport direction of the second pre-curing irradiation unit 43c. Thereby, power saving can be achieved.

  In this embodiment, half of the second provisional curing irradiation unit 43c is lit, but the LED lighting range of the second provisional curing irradiation unit 43c may be changed according to the transport amount. For example, when the transport amount is 1/4 of the nozzle row length, LEDs in a range of 1/4 on the upstream side in the transport direction of the second pre-curing irradiation unit 43c may be lit. In this way, further power saving can be achieved.

  Moreover, in this embodiment, the LED lighting range of the irradiation part 43c for 2nd temporary curing was the upstream of the conveyance direction. That is, the LED lighting range of the second temporary curing irradiation unit was adjacent to the first temporary curing irradiation unit 42a. Thereby, the time interval of 1st temporary hardening and 2nd temporary hardening was shortened.

  Therefore, the LED lighting range of the second pre-curing irradiation unit 43c may be set on the downstream side in the transport direction with the LED extinguishing range having a length that is an integral multiple of the transport amount or the transport amount interposed therebetween. By doing so, the time interval from the first temporary curing to the second temporary curing is increased. For example, in this case, the time for one pass or several passes and the transport operation becomes longer. That is, the dot spread time becomes longer and the dot becomes larger. In this way, the dot spreading time can be controlled by setting the LED lighting range of the second pre-curing irradiation unit 43c, and thereby the dot size can be controlled.

  In the present embodiment, in FIG. 12D, the dot immediately after formation and the dot that has been first provisionally cured once formed in the previous pass are mixed. The first temporary curing is performed by irradiating these dots with the first temporary curing UV from the downstream side in the transport direction of the first temporary curing amount irradiation unit 42a. That is, in the present embodiment, the difference in the UV irradiation amount of the first temporary curing to each dot in the region a is doubled. Therefore, the UV irradiation amount on the downstream side in the transport direction of the first pre-curing irradiation unit 42a (corresponding to the irradiation amount in FIG. 12D) is set to the UV irradiation amount on the upstream side in the transport direction (corresponding to the irradiation amount in FIG. 12B). May be increased. By doing so, the difference in the UV irradiation amount of the first temporary curing received by each dot can be reduced, and the dot shape can be formed more uniformly.

  Thus, in the fourth embodiment, after the first temporary curing is performed by the first temporary curing irradiation unit 42a (42b), the second temporary curing is performed by the second preliminary curing irradiation unit 43c (43d). Yes. Accordingly, it is possible to achieve both suppression of ink bleeding and obtaining gloss of an image.

Further, the second pre-curing irradiation portions 43c and 43d are provided on the downstream side in the transport direction from the printing region. Thereby, time until 2nd temporary hardening is performed is securable.
In addition, since the LEDs in the upstream area in the transport direction of the second pre-curing irradiation unit 43c are turned on and the LEDs in the downstream area in the transport direction are turned off, power saving can be achieved. In addition, by setting the lighting range of the second temporary curing irradiation unit 43c to the downstream side in the transport direction, it is possible to secure a longer time until the second temporary curing.

One of the second pre-curing irradiation units 43c and 43d may be lit and used for the second pre-curing, or both may be lit and the second pre-curing irradiation units 43c and 43d may be used for the second pre-curing irradiation unit 43c and 43d. 2 You may make it harden | cure.
In the above-described embodiment, as shown in FIG. 11, in order to form a dot between raster lines with a nozzle pitch interval formed in one pass, in another pass, the nozzle row is conveyed. Although the transport amount is shorter than the length in the direction, one raster line may be formed by a plurality of passes instead of or in addition to this. Also in this case, the carry amount is shorter than the length of the nozzle row.
=== Fifth Embodiment ===
<About printer configuration>
FIG. 13 is an explanatory diagram of the head portion of the fifth embodiment. Compared to the second embodiment, the shape of the second pre-curing irradiation part is different. Moreover, compared with 4th Embodiment, the position and shape of the irradiation part for 2nd temporary hardening differ.
As shown in FIG. 13, in the fifth embodiment, second preliminary curing irradiation units 43e and 43f are provided on the upstream side in the transport direction outside the first temporary curing irradiation units 42a and 42b of the carriage 21, respectively. Yes.
The length in the transport direction of the second pre-curing irradiation units 43e and 43f is shorter than the length in the transport direction of the first pre-curing irradiation units 42a and 42b and corresponds to the transport amount of the medium. For example, if the transport amount is predetermined as 1/4 of the nozzle row length, the length in the transport direction of the second pre-curing irradiation units 43e and 43f is 1/4 of the nozzle row length. However, as in the second embodiment, the second provisional curing irradiation units 43a and 43b may be configured and set to a lighting range as shown in FIG. 13 according to the transport amount.

Further, the UV irradiation amount of the second pre-curing irradiation units 43e and 43f is larger than the UV irradiation amount of the first pre-curing irradiation units 42a and 42b. This is because, as described above, the first temporary curing and the second temporary curing have different functions.
As in the second embodiment, the positions of the second pre-curing irradiation units 43e and 43f may be adjustable in the moving direction by a guide (not shown) on the carriage 21. By doing so, the distance between the head 31 and the first temporary curing irradiation unit 42a (42b) and the second preliminary curing irradiation unit 43e (43f) can be adjusted, and the timing of the second temporary curing can be adjusted. Thereby, the dot size can be adjusted.

<Printing Operation of Fifth Embodiment>
The dot formation and UV irradiation of the fifth embodiment are substantially the same as those in FIG. 12 of the fourth embodiment. However, in the fifth embodiment, the temporary curing in FIG. 12E is immediately after the dot formation in FIG. 12C and the first temporary curing in FIG. 12D (in the same pass as the dot formation in FIG. 12C and the first temporary curing in FIG. 12D). Become).

In the fifth embodiment, as in the second embodiment, the timing of the second temporary curing is determined by the distance between the first temporary curing irradiation unit and the second temporary curing irradiation unit. For this reason, you may enable it to adjust the position of the irradiation part 43a for 2nd temporary hardening according to a timing.
Furthermore, the position in the transport direction of the second pre-curing irradiation units 43e and 43f may be changed. For example, as the second pre-curing irradiation units 43e and 43f are provided on the downstream side in the transport direction, the time until the second pre-hardening is performed can be increased.

  Thus, in the fifth embodiment, after the first temporary curing is performed by the first temporary curing irradiation unit 42a (42b), the second temporary curing is performed by the second preliminary curing irradiation unit 43e (43f). Yes. Accordingly, it is possible to achieve both suppression of ink bleeding and obtaining gloss of an image.

  In the fifth embodiment, the second pre-curing irradiation units 43e and 43f are provided outside the first pre-curing irradiation units 42a and 42b on the carriage 21, respectively. Thereby, in the pass, after performing the first temporary curing, the second temporary curing can be subsequently performed. Further, the time until the second temporary curing is performed can be adjusted by changing the distance between the second preliminary curing irradiation unit 43e (43f) and the first temporary curing irradiation unit 42a (42b). That is, the spread of dots can be adjusted.

=== 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.
In each of the above-described embodiments, the length of the second temporary curing irradiation unit 43 in the transport direction is the same as the length of the transport amount, but the length of the second temporary curing irradiation unit 43 in the transport direction is The second temporary curing may be performed by an integral number of times of the length of the conveyance amount. In this case, the dots are fixed by an integer number of times of the second pre-curing, but it is only necessary to set the pre-curing conditions in consideration of the fact that the dots slightly spread even during the second number of times of the second pre-curing. . Further, the length in the transport direction of the second pre-curing irradiation unit 43 may be the length in the transport direction of the illuminated region of the length of the second pre-curing irradiation unit 43 in the transport direction.

<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 liquid ejection devices to which inkjet technology such as a device and a DNA chip manufacturing device is applied.

<About nozzle>
In the above-described embodiment, ink is ejected using a piezoelectric element (piezo element). However, the method for discharging the liquid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

<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, an electromagnetic wave (such as visible light) for curing the liquid may be irradiated from each irradiation unit.

1 printer, 10 transport unit, 11 paper feed roller,
13 transport roller, 14 platen, 15 paper discharge roller,
20 carriage unit, 21 carriage,
30 head units, 31 heads,
40 irradiation unit, 42a, 42b first temporary curing irradiation unit,
43, 43a to 43f Second provisional curing irradiation unit, 44 main curing irradiation unit,
50 detector group, 53 paper detection sensor, 54 optical sensor 60 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit,
110 computer

Claims (5)

A nozzle row in which a plurality of nozzles that discharge liquid that is cured by being irradiated with electromagnetic waves are arranged in the first direction;
A first irradiation unit, a second irradiation unit, and a third irradiation unit capable of irradiating the liquid that has landed on the medium with the electromagnetic wave;
A carriage unit that moves the nozzle row, the first irradiation unit, the second irradiation unit, and the third irradiation unit in a second direction that intersects the first direction;
The first irradiation unit is disposed at a position that can be opposed to a region where at least one of the plurality of nozzles of the nozzle row is opposed when the carriage unit moves in the second direction,
The third irradiation section is disposed between the second irradiation unit and the Oite the first irradiation portion in a first direction,
The liquid ejection device capable of irradiating the second irradiating unit with the electromagnetic wave that is larger than the irradiation amount of the electromagnetic wave irradiated by the first irradiating unit in a state where the electromagnetic wave is not irradiated from the third irradiating unit. The liquid ejection device according to claim 1,
The nozzle row has a color nozzle row for discharging color ink,
The liquid ejecting apparatus, wherein the third irradiation unit is located closer to the second irradiation unit than a region where the color ink lands on the medium. The liquid ejection device according to claim 1 or 2,
The liquid ejection apparatus, wherein a position of the second irradiation unit in the first direction is adjustable. The liquid ejection device according to any one of claims 1 to 3,
A transport unit configured to transport the medium in the direction from the first irradiation unit toward the second irradiation unit along the first direction;
A control unit that controls the nozzle, the carriage unit, and the transport unit;
The control unit can perform a transport operation for transporting the medium, and a liquid discharge operation for discharging liquid from the nozzle while moving the carriage unit in the second direction.
The liquid ejection apparatus, wherein a length of the third irradiation unit in the first direction is an integral multiple of a transport distance of the medium in one transport operation. A transport unit for transporting the medium in the transport direction;
A nozzle that discharges a liquid that is cured by being irradiated with electromagnetic waves;
A first irradiation unit capable of irradiating the electromagnetic wave to the liquid landed on a medium;
A second irradiation unit that is located downstream of the first irradiation unit in the transport direction and that can irradiate the liquid irradiated with the electromagnetic wave from the first irradiation unit;
A third irradiation unit located between the first irradiation unit and the second irradiation unit in the transport direction and capable of irradiating the electromagnetic wave to the liquid;
The liquid ejection device capable of irradiating the second irradiating unit with the electromagnetic wave that is larger than the irradiation amount of the electromagnetic wave irradiated by the first irradiating unit in a state where the electromagnetic wave is not irradiated from the third irradiating unit.

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