JP5673740B2 - 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, or the irregularity of the medium surface constituted by the dots will increase, The glossiness of the image may be deteriorated.
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.

The main invention for achieving the above object is:
A transport unit for transporting the medium in the transport direction;
A plurality of nozzles that discharge a liquid that is cured by irradiation of electromagnetic waves are arranged along the transport direction, and a nozzle array that moves in a movement direction that intersects the transport direction;
An irradiation unit that moves in the moving direction together with the nozzle row and irradiates the electromagnetic wave;
A control unit for controlling the irradiation unit;
With
A transport operation for transporting the medium in the transport direction by a predetermined transport amount by the transport unit, and dot formation for forming dots on the medium by ejecting the liquid from the nozzles while moving the nozzle row A liquid ejection device that repeats operation,
The irradiation unit is
A first irradiation unit that is provided at a position aligned with the nozzle row in the movement direction, and irradiates the electromagnetic wave in a range where the nozzle row forms dots during the dot forming operation;
A second irradiation unit that is provided downstream of the first irradiation unit in the conveyance direction and irradiates the electromagnetic wave having an irradiation amount larger than the irradiation amount of the electromagnetic wave of the first irradiation unit in a range corresponding to the conveyance amount. When,
Have
The control unit slows the spreading speed of the dots by irradiating the electromagnetic waves of the first irradiating unit, stops the spreading of the dots by irradiating the electromagnetic waves of the second irradiating unit, and controls the electromagnetic waves of the first irradiating unit. Controlling the size of the dots by controlling the amount of irradiation or the timing of irradiating the electromagnetic wave from the second irradiation unit,
This is a liquid discharge apparatus.
In addition, the liquid ejection apparatus of the present invention includes a transport unit that transports the medium in the transport direction, a nozzle that moves in a moving direction that intersects the transport direction, and discharges a liquid that is cured by irradiation with electromagnetic waves, and the nozzle together An irradiation unit that moves in a moving direction and irradiates the electromagnetic wave, and a control unit, wherein the irradiation unit irradiates the electromagnetic wave to the liquid that has landed on the medium, and the first irradiation. The liquid that is not irradiated with the electromagnetic wave is formed between the first irradiation unit and the first irradiation unit, and the liquid irradiated with the electromagnetic wave from the first irradiation unit is formed between the first irradiation unit and the liquid. A second irradiating unit that irradiates the electromagnetic wave with an irradiation amount greater than the irradiation amount of the electromagnetic wave of the first irradiating unit; Slows the spread speed , By irradiation of the electromagnetic wave of the second irradiating unit stops the spread of the liquid may be a liquid ejecting apparatus.

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 dot shape and the UV irradiation timing. FIG. 6A to FIG. 6F are explanatory diagrams of image formation according to the first embodiment. FIG. 7A to FIG. 7D are explanatory diagrams of the state of image formation according to the second embodiment.

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

A transport unit that transports the medium in the transport direction and a nozzle array in which a plurality of nozzles that eject liquid that is cured by electromagnetic wave irradiation are arranged along the transport direction, and moves in a moving direction that intersects the transport direction A nozzle row, and an irradiation unit that moves in the movement direction together with the nozzle row and irradiates the electromagnetic wave, and a transport operation for transporting the medium in the transport direction by a predetermined transport amount by the transport unit; A liquid ejecting apparatus that repeats a dot forming operation for forming dots on the medium by ejecting the liquid from the nozzles while moving the nozzle rows, wherein the irradiation unit moves in the moving direction with respect to the nozzle rows. More than the first irradiation unit, the first irradiation unit provided at the position where the nozzle row irradiates the electromagnetic wave in a range in which the nozzle row forms dots during the dot formation operation; Serial provided downstream in the transport direction, having a second irradiation unit which irradiates the electromagnetic wave in a range corresponding to the carry amount, it becomes clear that a liquid discharge apparatus according to claim.
According to such a liquid ejecting apparatus, it is possible to achieve both suppression of bleeding and gloss and density of an image, and good image quality can be obtained when a liquid that is cured by irradiation with electromagnetic waves is used.

In this liquid ejection apparatus, the second irradiation unit can irradiate the electromagnetic wave in a range corresponding to a range in which the nozzle row forms dots on the downstream side in the transport direction of the first irradiation unit. Is desirable.
According to such a liquid ejecting apparatus, it is possible to cope with printing methods having different conveyance amounts.

In such a liquid ejection apparatus, it is preferable that an area of the second irradiation unit that irradiates the electromagnetic wave is set according to the transport amount.
According to such a liquid discharge apparatus, power saving can be achieved.

In the liquid ejecting apparatus, it is preferable that there is a region where the electromagnetic wave of the second irradiation unit is not irradiated between the region of the second irradiation unit that irradiates the electromagnetic wave and the first irradiation unit.
According to such a liquid ejecting apparatus, it is possible to control the size of dots and the gloss and density of an image.

In this liquid ejection apparatus, it is desirable that the electromagnetic wave irradiation amount of the second irradiation unit is equal to or larger than the electromagnetic wave irradiation amount of the first irradiation unit.
According to such a liquid ejection device, it is possible to obtain the gloss and density of an image while suppressing bleeding between dots.

  In addition, a transport unit that transports the medium in the transport direction, and a nozzle row in which a plurality of nozzles that discharge a liquid that is cured by irradiation with electromagnetic waves are arranged along the transport direction, and a moving direction that intersects the transport direction A nozzle row that moves in the movement direction together with the nozzle row, and an irradiation unit that irradiates the electromagnetic wave, and the conveyance unit conveys the medium in the conveyance direction by a predetermined conveyance amount. And a dot forming operation for forming dots on the medium by discharging the liquid from the nozzle while moving the nozzle row, and the irradiation unit moves with the nozzle row. A first irradiation unit that is provided at a position aligned in a direction and that irradiates the electromagnetic wave in a range in which the nozzle row forms dots during the dot formation operation; and the first irradiation unit Provided remote the downstream side, with a, a second irradiation unit which irradiates the electromagnetic wave in a range corresponding to an integral multiple of the conveying quantity, it becomes clear that a liquid discharge apparatus according to claim.

  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 this embodiment includes first temporary curing irradiation units 42 a and 42 b, second temporary curing irradiation units 43 a and 43 b, 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 units 43a and 43b correspond to the second irradiation unit. The first temporary curing irradiation units 42 a and 42 b and the second temporary curing irradiation units 43 a and 43 b are provided on the carriage 21. For this reason, when the carriage 21 moves in the movement direction, the first temporary curing irradiation units 42a and 42b and the second temporary curing irradiation units 43a and 43b also move in the movement direction.

  The first pre-curing irradiation portions 42 a and 42 b are provided on one end side and the other end side in the moving direction of the head 31 on the carriage 21 so as to sandwich the head 31. 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. In other words, the first pre-curing irradiation units 42 a and 42 b are provided at positions aligned with the nozzle rows of the head 31 in the movement direction. Then, the first temporary curing irradiation units 42a and 42b move together with the head 31 to irradiate UV to a range where the nozzle row of the head 31 forms dots. 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. In addition, the first temporary curing irradiation units 42a and 42b of the present embodiment include a plurality of LEDs along the transport direction, and the UV irradiation range (transport direction) is controlled by controlling the turning on and off of each LED. Range) can be set. For example, when only half of the nozzle row of the head 31 on the downstream side in the transport direction is used, it is possible to irradiate UV to a range where the half nozzles form dots.

  The second pre-curing irradiation units 43a and 43b are provided on the downstream side in the transport direction of the first pre-curing irradiation units 42a and 42b, respectively. The length in the transport direction of the second pre-curing irradiation units 43a and 43b is the same as the length in the transport direction of the first pre-curing irradiation units 42a and 42b (that is, the length of the nozzle row of the head 31). It has become.

  Similarly to the first temporary curing irradiation units 42a and 42b, the second temporary curing irradiation units 43a and 43b of the present embodiment also include LEDs as light sources for UV irradiation. Further, the second pre-curing irradiation units 43a and 43b are also provided with a plurality of LEDs along the transport direction, and the UV irradiation range (range in the transport direction) is controlled by controlling the turning on and off of each LED. Can be set. In the present embodiment, the second pre-curing irradiation units 43a and 43b irradiate UV in a range corresponding to the transport amount of the medium.

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 42a and 42b and the second temporary curing irradiation units 43a and 43b. 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 (after pass 2) 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 in order to obtain a predetermined density image.
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. And / or the print density is increased. 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. When the timing of pre-curing is determined, the size of the dot is determined by the size at the time of pre-curing (when UV is irradiated from the pre-curing irradiation unit). 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. 6F are explanatory diagrams of image formation according to the first embodiment.
In these drawings, the dot forming operation (pass) and the conveying operation in the first embodiment are shown in order. In each figure, the hatched (hatched) portion of the head 31 indicates the range of nozzles that eject ink, and the non-hatched portion indicates the range of nozzles that do not eject ink. Moreover, the hatching part of each irradiation part shows the area | region which turns on LED (area | region which irradiates UV), and the non-hatching part has shown the area | region which turns off LED (area | region which does not irradiate UV).
In the present embodiment, the medium conveyance amount in the conveyance operation is half the nozzle row length of the head 31.

  First, as shown in FIG. 6A, in the first pass (outward path), the controller 60 moves the carriage 21 in the moving direction (outward direction) while moving the upstream side of the head 31 in the transport direction (the side with the larger nozzle number). UV ink is ejected from each of the half nozzles. At this time, dots are formed, for example, every other pixel in the moving direction by each nozzle. In this way, dots are formed in the first pass (pass 1) using half of the nozzles on the upstream side of the nozzle row of the head 31. Thereby, a dot row in which dots are arranged in the transport method is formed every other pixel in the moving direction.

Further, the controller 60 causes the first temporary curing irradiation unit (in this case, the first temporary curing irradiation unit 42a) on the upstream side in the moving direction of the head 31 to irradiate UV. At this time, the controller 60 turns on the LED of the portion corresponding to the range in which the nozzles on the upstream side in the transport direction of the head 31 form dots (shaded portions in the drawing) of the first temporary curing irradiation unit 42a. Is irradiated. In this way, UV irradiation is performed only in pass 1 by using the half region on the upstream side of the first temporary curing irradiation unit.
In pass 1 (and pass 2 described later), the second provisional curing irradiation parts 43a and 43b are not used (UV irradiation is not performed).

In the present embodiment, the first pre-curing irradiation section 42a is provided on the carriage 21 at a position aligned with the nozzle row of the head 31 in the movement direction. Temporary curing is performed. As described above, by performing the first temporary curing at the timing immediately after the dot formation, bleeding between dots can be suppressed.
By this pass 1, an image is printed on the area A of the medium as shown in FIG. 6B. Note that the printed image in the region A is in a state after the first temporary curing (a state in which bleeding is suppressed but dots continue to spread).
The printed image in the area A is an incomplete image (an image having only half the dots of the completed image).

  After pass 1, the controller 60 transports the medium by a transport amount that is half the nozzle row length (transport operation). By this transport operation, as shown in FIG. 6C, the print image in the region A in FIG. 6B is positioned downstream in the transport direction of the print region.

  After the carrying operation, the controller 60 causes pass 2 (return pass). 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).

  At this time, the controller 60 forms dots at every other pixel in the moving direction by the half of the nozzles on the upstream side in the transport direction of the head 31 (the side with the larger nozzle number), as in pass 1. Further, the controller 60 uses a half nozzle on the downstream side in the transport direction (smaller nozzle number side) to form a dot row (in the transport direction) formed by the half nozzle on the upstream side in the transport direction in the previous pass (forward path). Dots are formed between the aligned dot rows. For example, when dots are formed in odd rows in the previous pass, dots are formed in even rows in the next pass.

In the pass 2 (return path), the controller 60 irradiates the UV with the first temporary curing irradiation unit 42b (the hatched line in the drawing) on the upstream side in the moving direction of the head 31. In FIG. 6C, since the moving direction is opposite to that in FIG. 6A, the first temporary effect irradiation unit used for the first temporary curing is opposite to that in FIG. 6A.
In this pass 2 as well, the second temporary curing irradiation parts 43a and 43b are not used.

  Since the first temporary curing irradiation part 42b is provided in the carry 21 at a position aligned with the nozzle row of the head 31 in the moving direction, the first temporary curing is performed immediately after the dot formation. As described above, the first temporary curing is performed immediately after the dot formation, thereby preventing bleeding between the dots.

  In this pass 2, the first temporary curing irradiation unit 42b also irradiates the image of FIG. 6B (dots subjected to the first temporary curing UV irradiation) with UV. That is, the portion (dot) formed in FIG. 6B in the half (region A in the figure) on the downstream side in the conveyance direction of the image in FIG. 6D receives the first pre-curing UV irradiation twice.

  Thus, the printed image shown in FIG. 6D is in a state after the first temporary curing. However, in the printed image of FIG. 6D, the upstream half (region B) in the transport direction is only the dots that have undergone the first temporary curing once, and the downstream half (region A) in the transport direction is the first temporary cure. The dot that has been performed once and the dot that has been performed twice are mixed.

  In addition, the image in the region B is an incomplete image (an image having only half the dots of the completed image), and the image in the region A is a completed image.

  After pass 2, the controller 60 transports the medium by a transport amount that is half the nozzle row length (transport operation). By this transport operation, as shown in FIG. 6E, the region B in FIG. 6D is positioned on the upstream side in the transport direction of the print region, and the region A in FIG. 6D is positioned on the downstream side in the transport direction with respect to the print region.

  In pass 3 (outward pass), the controller 60 discharges UV ink from each nozzle of the head 31 while moving the carriage 21 in the movement direction (outward direction), as shown in FIG. 6E. At this time, the controller 60 forms dots at every other pixel in the movement direction by the half of the nozzles on the upstream side in the transport direction (the side with the larger nozzle number), as in pass 2. Also, dots are formed between the dot rows formed by the upstream half nozzles in the previous pass (return pass) by the half nozzles on the downstream side in the transport direction (smaller nozzle number side).

  Further, the controller 60 irradiates the UV with the first temporary curing irradiation section 42a (the hatched line in the drawing) on the upstream side in the moving direction of the head 31 in the pass 3 (outward path). In FIG. 6E, since the moving direction is opposite to that in FIG. 6C, the first temporary effect irradiation part used for the first temporary curing is opposite to that in FIG. 6C.

  In addition, the controller 60 is an LED corresponding to the downstream half of the second temporary curing irradiation unit (in this case, the second preliminary curing irradiation unit 43a) on the upstream side in the movement direction of the head 31 (for the conveyance amount). Lights up. Thereby, UV is irradiated to the dot of the area | region A (The part where the 1st temporary hardening is 1 time and the dot of 2 times mixed) conveyed downstream in the conveyance direction of the printing area | region. In the present embodiment, since the second pre-curing irradiation portions 43a and 43b are provided at positions protruding from the nozzle row of the head 31 (downstream in the transport direction), the dots formed in the previous pass are 2 Pre-curing UV can be irradiated.

  Thus, in the present embodiment, the second temporary curing is performed in a pass after the pass in which the 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. If the second temporary curing is performed immediately after the dot formation, the dots do not spread (see FIG. 5A), so that the irregularities on the surface of the medium constituted by the dots increase and the gloss deteriorates, or the dot area decreases and printing is performed. The concentration will decrease.

  The print image shown in FIG. 6F is in a state after the first temporary curing in the print region (region B and region C) (a state in which bleeding is suppressed but dots continue to spread). Note that the upstream half (area C) in the transport direction of the printing area is formed by only dots that have undergone the first temporary curing once, and the first half of the printing direction downstream half (area B) is subjected to the first temporary curing once. A dot that has been performed and a dot that has been performed twice are mixed.

In addition, the image on the downstream side in the conveyance direction (area A) from the printing area is in a state after the second temporary curing (a state where the spread of dots has stopped).
Note that the image in the region C is an incomplete image (an image having only half the dots of the completed image), and the images in the region A and the region B are completed images.

  Thereafter, similarly, the controller 60 repeatedly performs the pass and the transport operation alternately. As a result, images are sequentially 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.

  In the first embodiment, UV irradiation (LED is turned on) from the area corresponding to half of the transport amount of the transport operation in the second pre-curing irradiation unit 43a is performed. The lighting range may be changed. For example, when the transport amount is ¼ of the nozzle row length, UV irradiation may be performed from a ¼ region upstream of the transport direction in the second temporary curing irradiation unit 43a (43b). Good.

  Further, if the transport amount of the transport operation is determined in advance, the length of the second temporary curing irradiation portions 43a and 43b may be a length corresponding to the transport amount. In this case, it is not possible to cope with a plurality of printing modes with different transport amounts, but the length of the second provisional curing irradiation units 43a and 43b does not have to be the length of the nozzle row of the head 31, and therefore the second provisional curing irradiation. The parts 43a and 43b can be shortened.

  As described with reference to FIG. 6, in the present embodiment value, when the second temporary curing is performed, the first temporary curing includes a single dot and two dots. That is, there is a double difference in the UV irradiation amount of the first temporary curing. Therefore, the first temporary curing irradiation units 42a and 42b are each divided into two regions in the transport direction so that the UV irradiation amount on the downstream side in the transport direction is larger than the UV irradiation amount on the upstream side in the transport direction. Good. By doing so, the difference in the irradiation amount of the first temporary curing of each dot can be reduced. Thereby, the shape of a dot can be made more uniform.

  As described above, in the printer 1 of the present embodiment, after the first temporary curing is performed immediately after the dot formation, the second temporary curing is performed in a pass after the pass in which the dots are formed. Therefore, it is possible to secure the time from performing the first temporary curing to performing the second temporary curing, and in consideration of the fact that the dots spread a little during this period, the dots are finally desired by the second temporary curing. Irradiation conditions for the first temporary curing and the second temporary curing are set so that the size is fixed. This makes it possible to achieve both suppression of blurring and obtaining gloss and density.

  The second pre-curing irradiation units 43a and 43b are provided downstream of the first pre-curing irradiation units 42a and 42b in the transport direction, and the length in the transport direction is the same as the length of the nozzle row. It has become. Thereby, even when printing methods with different carry amounts are performed, the second pre-curing UV can be irradiated to the dot formation range.

  In addition, the second pre-curing irradiation units 43a and 43b have a plurality of LEDs along the transport direction, and the UV irradiation range can be set by turning on and off the LEDs. For this reason, UV can be irradiated only to the part conveyed downstream from the printing area | region by the conveyance operation | movement in the conveyance direction. Thereby, power saving can be achieved.

=== Second Embodiment ===
In 1st Embodiment, the lighting range of LED of the irradiation parts 43a and 43b for 2nd temporary hardening was the conveyance direction upstream. That is, the LED lighting range of the second pre-curing irradiation units 43a and 43b is adjacent to the first pre-curing irradiation units 42a and 42b, but in the second embodiment, the second pre-curing irradiation units 43a and 43b. The LED lighting range is set on the downstream side in the transport direction.

FIG. 7A to FIG. 7D are explanatory diagrams of the state of image formation according to the second embodiment.
In the second embodiment, the same operation is performed from FIG. 6A to FIG. 6D of the first embodiment. 7A to 7D are explanatory diagrams of operations after that.

  After the transport operation in FIG. 6D (the transport operation after pass 2), as shown in FIG. 7A, the region B (the portion where the first temporary curing is only one dot) is downstream in the transport direction of the print region. The region A (the portion in which the first temporary curing is mixed with one dot and the two dots) is located on the downstream side in the transport direction with respect to the printing region.

  In pass 3 (outward path), as shown in FIG. 7A, the controller 60 discharges UV ink from each nozzle of the head 31 while moving the carriage 21 in the movement direction (outward direction). At this time, the controller 60 forms dots at every other pixel in the movement direction by the half of the nozzles on the upstream side in the transport direction (the side with the larger nozzle number), as in pass 2. Also, the controller 60 forms dots between the dot rows formed by the upstream half nozzles in the previous pass (return pass) by the half nozzles on the downstream side in the transport direction (side with the smaller nozzle number). Let

  In the pass 3 (outward path), the controller 60 irradiates the UV with the first pre-curing irradiation unit 42 a located on the upstream side in the moving direction of the head 31. In FIG. 6E, since the moving direction is opposite to that in FIG. 6C, the first temporary effect irradiation part used for the first temporary curing is opposite to that in FIG. 6C.

  However, in the case of the second embodiment, in pass 3 shown in FIG. 7A, the controller 60 turns off the LED of the second temporary curing irradiation unit 43a on the upstream side in the moving direction of the head 31. That is, the second pre-curing UV irradiation is not performed in this pass.

  Therefore, in the image after pass 3 (outward path) shown in FIG. 7B, the area C in the upstream half of the printing area is in a state after the first temporary curing is performed once, and the area B and the area A In (a half on the downstream side of the printing area + one conveyance amount from the downstream end of the printing area), the dot that has been subjected to the first temporary curing once and the dot that has been performed twice are mixed. .

  In addition, the image in the region C is an incomplete image (an image having only half the dots of the completed image), and the images in the region A and the region B are completed images.

  After pass 3, the controller 60 transports the medium by a transport amount that is half the nozzle row length (transport operation). By this transport operation, as shown in FIG. 7C, the upstream side in the transport direction in the print area of FIG. 7B is positioned downstream in the transport direction in the print area. In addition, a region where the first and second temporary curing dots are mixed is a position aligned with the second temporary curing amount irradiation units 43a and 43b in the moving direction.

  Then, in pass 4 (return path bus), as shown in FIG. 7C, the controller 60 ejects UV ink from each nozzle of the head 31 while moving the carriage 21 in the movement direction (return path direction). At this time, the controller 60 forms dots at every other pixel in the movement direction by using half of the nozzles on the upstream side in the transport direction (the side with the larger nozzle number). Also, the controller 60 forms dots between the dot rows formed by the upstream half nozzles in the previous pass (outward pass) by the half nozzles on the downstream side in the transport direction (side with the smaller nozzle number). Let

  Further, in the pass 4 (return path), the controller 60 irradiates the UV by the first temporary curing irradiation unit 42b located on the upstream side in the moving direction of the head 31. In FIG. 7C, since the moving direction is opposite to that in FIG. 7A, the first temporary effect irradiation unit used for the first temporary curing is opposite to that in FIG. 7A.

  Further, in pass 4, as shown in FIG. 7C, the controller 60 corresponds to the downstream half of the second temporary curing irradiation unit 43b on the upstream side in the movement direction of the head 31 (for the conveyance amount). Is turned on, and the second pre-curing UV is irradiated. By doing so, it is possible to secure a time until the second temporary curing is performed further than in the first embodiment. Specifically, in the first embodiment, the second pre-curing UV is irradiated in pass 3 to the region (region A) that has been subjected to the first pre-curing UV irradiation in pass 2 for the second time. In contrast, in the second embodiment, the same region A is irradiated with UV of the second temporary curing in pass 4. That is, the time from the first temporary curing to the second preliminary curing is longer than that of the first embodiment by one pass and one transport operation.

  In this way, the lighting range of the second temporary curing irradiation units 43a and 43b is set to the downstream side in the transport direction (that is, a region not irradiated with UV is provided between the irradiation region with the first temporary curing amount irradiation unit). Thus, the timing of the second temporary curing can be further delayed. As described above, in the second embodiment, the time interval from the first temporary curing to the second temporary curing can be set longer than that in the first embodiment.

  In addition, although UV irradiation (LED was lit) from the area | region equivalent to the downstream half of the conveyance amount of conveyance operation | movement among 2nd provisional curing irradiation parts 43a and 43b, the lighting range of LED according to conveyance amount is carried out. May be changed. For example, when the transport amount is 1/4 of the nozzle row length, the LED in the 1/4 region on the downstream side in the transport direction of the second temporary curing irradiation unit 43a (43b) may be turned on. Furthermore, you may change the position of the lighting range of LED. In addition, the timing of 2nd temporary hardening can be delayed, so that a lighting range is located in the conveyance direction downstream.

  As described above, in the second embodiment, since a region where UV is not irradiated is provided between the first temporary curing irradiation unit and the second temporary curing irradiation unit, the timing for performing the second temporary curing (that is, the dot) Spread time). Thereby, the size, gloss, and density of the dots can be controlled.

=== 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 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.

<About the irradiation part for temporary curing>
In the above-described embodiment, the first temporary curing irradiation unit and the second temporary curing irradiation unit are separated. However, the present invention is not limited to this. If the irradiation amount of the electromagnetic wave for the second temporary curing may be the same as the irradiation amount of the first temporary curing, the temporary curing irradiation unit may be configured integrally.

  In the present embodiment, the upstream side in the moving direction of the head 31 among the second pre-curing irradiation units 43a and 43b is lit, but at least one of the second pre-curing irradiation units 43a and 43b can be lit. That's fine. For example, in FIG. 6E, the second temporary curing irradiation unit 43b may be turned on. Alternatively, both of them may be turned on and second pre-curing may be performed by both of the second pre-curing irradiation units 43a and 43b.

  Alternatively, the second temporary curing may be performed for an integral number of times by setting the lighting range of the second temporary curing irradiation units 43a and 43b to an integral multiple of the length of the conveyance amount. In this case, the dots are fixed by an integer number of times of the second temporary curing, but the provisional curing conditions may be set in consideration of the fact that the dots spread slightly even during the second number of times of the second temporary curing. Further, the length in the transport direction of the second pre-curing irradiation units 43a and 43b may be the length in the transport direction of the lighted area of the length in the transport direction of the second pre-curing irradiation units 43a and 43b. . Also in this case, it is possible to achieve both suppression of blurring and obtaining gloss and density, and good image quality can be obtained.

  DESCRIPTION OF SYMBOLS 1 Printer, 10 conveyance unit, 11 Paper feed roller, 13 Transport roller, 14 Platen, 15 Paper discharge roller, 20 Carriage unit, 21 Carriage, 30 Head unit, 31 Head, 40 Irradiation unit, 42a, 42b For 1st temporary curing Irradiation unit, 43a, 43b Second temporary 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 (4)

A transport unit for transporting the medium in the transport direction;
A nozzle that moves in a moving direction intersecting the transport direction and discharges a liquid that is cured by irradiation with electromagnetic waves;
An irradiation unit that moves in the moving direction together with the nozzle and irradiates the electromagnetic wave;
A control unit;
With
The irradiation unit is
A first irradiation unit that irradiates the electromagnetic wave to the liquid that has landed on the medium;
Provided on the downstream side in the transport direction from the first irradiation unit so that a region not irradiated with the electromagnetic wave is formed between the first irradiation unit and the electromagnetic wave is irradiated from the first irradiation unit. A second irradiation unit that irradiates the liquid with the electromagnetic wave having an irradiation amount greater than the irradiation amount of the electromagnetic wave of the first irradiation unit;
The control unit slows down the spreading speed of the liquid by irradiating the electromagnetic wave of the first irradiating unit, and stops the spreading of the liquid by irradiating the electromagnetic wave of the second irradiating unit.
Liquid ejection device. The liquid ejection device according to claim 1,
The length in the transport direction of the region irradiating the electromagnetic wave in the second irradiation unit is shorter than the length in the transport direction of the region irradiating the electromagnetic wave in the first irradiation unit.
Liquid ejection device. The liquid ejection device according to claim 1 or 2, wherein
The length of the second irradiation unit in the transport direction is shorter than the length of the first irradiation unit in the transport direction,
Liquid ejection device. The liquid ejection device according to any one of claims 1 to 3,
The controller is
A transport operation for transporting the medium in the transport direction by a predetermined transport amount by the transport unit;
A dot forming operation of forming dots on the medium by discharging the liquid from the nozzle while moving the nozzle in the moving direction; and
The second irradiation unit can irradiate the electromagnetic wave in a range corresponding to an integral multiple of the transport amount.
Liquid ejection device.

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