JP6047927B2 - Droplet ejecting apparatus and printing method - Google Patents

Description

  The present invention relates to a droplet ejecting apparatus, a printed matter, and a printing method.

In recent years, printing technology using UV ink has been known. The UV ink is an ink that cures when irradiated with UV light (ultraviolet light), and is fixed to a non-absorbing material to be printed. The non-absorbing material is a material that does not absorb or hardly absorbs normal ink. When the UV ink is cured on the non-absorbing material, the UV ink is fixed in a state of protruding from the material. For example, a printer using UV ink can print a projected image on a substrate.
By the way, in printing, shading unevenness, color unevenness and the like are related to printing quality. For example, printed matter may have uneven stripes (banding). As a technique related to this banding, for example, the technique of Patent Document 1 is known.

JP 2009-119806 A

  However, the height of the ink protruding from the substrate also affects the print quality. Therefore, the technique described in Patent Document 1 may not improve the printing quality.

  SUMMARY An advantage of some aspects of the invention is that it is a droplet ejecting apparatus that prints dots protruding from the surface of a substrate, and at least two of the dots are connected. And a droplet ejecting apparatus that prints an image including a set of dots.

  According to another aspect of the present invention, the droplet ejecting apparatus includes an ejecting unit that ejects each of the inks forming the dots toward a position where the dots are connected to each other.

  Further, according to one embodiment of the present invention, in the above-described droplet ejecting apparatus, at least one of the dots in the dot group is connected to another dot, so that the height from the printed material is Lower than when not connected.

  According to another aspect of the present invention, the droplet ejecting apparatus includes a fixing control unit that solidifies the ink ejected by the ejecting unit so that the at least two dots are connected and fixed.

  Another embodiment of the present invention is a printed material on which an image including a dot protruding from the surface of the printing material and a dot group in which at least two dots are connected is printed.

  Further, according to one embodiment of the present invention, an ejection process in which each of the inks forming the dots is ejected toward a position where dots protruding from the surface of the substrate are connected to each other, and at least two of the dots are connected and fixed. And a fixing control process for solidifying the ink ejected in the ejection process.

It is the schematic which shows the printed matter which concerns on embodiment of this invention. It is the schematic which shows the dot and dot group which concern on this embodiment. It is a schematic diagram which shows schematic structure of the droplet ejecting apparatus which concerns on this embodiment. It is a schematic diagram which shows schematic structure of the head unit which concerns on this embodiment. It is a top view which shows the ejection surface of the ejection head which concerns on this embodiment. It is a schematic block diagram which shows the logic structure of the control apparatus which concerns on this embodiment. It is the schematic which shows an example of the mask information which the mask production | generation part which concerns on this embodiment outputs. It is a flowchart which shows an example of operation | movement of the droplet ejecting apparatus which concerns on this embodiment. It is a top view which shows a motion of the ejection surface of the ejection head which concerns on this embodiment. It is the schematic which shows an example of the mask information which the mask production | generation part which concerns on the modification of this embodiment outputs. It is the schematic which shows the dot and dot group which concern on this modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a printed matter P1 according to an embodiment of the present invention. In this figure, the X-axis direction is the X-axis scanning direction during printing, and the Y-axis direction is the Y-axis scanning direction during printing (see FIG. 3). The printed material P1 is printed by curing and fixing UV (UltraViolet) ink on the non-absorbing material P0. Here, the non-absorbing material is a material that does not absorb or hardly absorbs ink. That is, the dots constituting the image and formed from the UV ink protrude from the surface of the substrate P0 (see FIG. 2B).

In FIG. 1, an enlarged view P11 is an enlarged view of a part of the printed matter P1. The dots I11 and I12 and the dot groups I13 to I15 in the enlarged view P11 are cured and fixed UV ink. Here, each of the dots I11 and I12 is obtained by curing the UV ink ejected toward one point. In the dot groups I13 and I14, UV inks jetted toward two different points intersect and are then cured. In the dot group I15, UV inks jetted toward three different points intersect and are then cured. That is, the dot groups I13 to I15 are obtained by connecting a plurality of dots.
Thus, the printed matter P1 includes an image composed of dot groups. In the present embodiment, a case will be described in which the printed matter P1 is a printed matter on which an image including dots I11 and I12 and dot groups I13 to I15 in which at least two dots are connected is printed. . However, the present invention is not limited to this, and the printed matter P1 may be an image printed with only a dot group.

FIG. 2 is a schematic diagram showing dots I11 and I12 and dot groups I13 and I14 according to the present embodiment. The X axis, Y axis, and Z axis in FIG. 2 are the same as those in FIG. Here, the X axis is graduated for each distance a. The dots I11 and I12 and the dot groups I13 and I14 are those shown in FIG.
In FIG. 2, for simplicity of explanation, the amount of UV ink per drop is the same, dots I11 and I12 are formed with one drop of UV ink, and dots I13 and I14 are formed with two drops of UV ink. And However, the present invention is not limited to this, and the amount of UV ink per droplet may be different.

FIG. 2A is a plan view when the printed surface (XY plane) of the printed material P1 is observed facing the printed surface. The dot I12 is a circle centered on the center C12. The dot group I13 is oval. In the dot group I13, the UV ink ejected toward the center 131 intersects with the UV ink ejected toward the center 132, and then cured.
For example, the radius of curvature of the dashed curve A131 (part of the outline of the dot group) is r1, the curvature circle is the circle 131 (for example, the center is the center 131), the radius of curvature of the dashed curve A132 is r2, and the curvature circle is A circle 132 (for example, the center is the center 132) is assumed. In this case, the distance between the center 131 and the center 132 (“a” in FIG. 2A) is smaller than the sum of r1 and r2 (a <r1 + r2). That is, at least a part of the circle 131 and the circle 132 intersect. For this reason, the UV ink ejected toward two different points intersects to form a dot group I13 in which dots are connected.
The distance between the dots may be determined in advance based on, for example, the viscosity of the ink or the amount of ink ejected (for example, the amount of ink per droplet).

FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG. 2A and is an XZ plan view. In FIG. 2B, the dots I11 and I12 and the dot groups I13 and I14 are fixed in a state of protruding from the substrate P0. Here, as for the height protruding from the substrate P0 (the size of the dot on the Z-axis is also simply referred to as “height”), the dots I11 and I12 are T1. On the other hand, the height of the dot groups I13 and I14 is T2. Here, T2 is smaller than T1, that is, the heights of the dot groups I13 and I14 are lower than the heights of the dots I11 and I12.
Thus, for example, at least one of the dots in the dot group I13 (dots formed with UV ink ejected toward the center 131) is another dot (UV ink ejected toward the center 132). By connecting to the dots to be formed, the height from the printing material P0 is lower than when not connecting to other dots (for example, the dot I11).

<About the droplet ejection device>
FIG. 3 is a schematic diagram showing a schematic configuration of the droplet ejecting apparatus 1 according to the present embodiment. FIG. 3A is a plan view of the droplet ejecting apparatus 1. FIG. 3B is a side view of the droplet ejecting apparatus 1.
In FIG. 3, a droplet ejecting apparatus 1 includes a head mechanism unit 2 having an ejecting head 20 (ejecting unit), a supply / discharge mechanism unit 3, an ink supply unit (not shown), a maintenance unit 5, and a control unit. C1.

  The ejection head 20 is an inkjet ejection head. The ejection head 20 ejects UV ink as droplets toward the surface of the substrate P0. In addition, as the to-be-printed material P0, flexible films, such as a polyethylene terephthalate (PET) and polyethylene (PE), are used, for example.

  The supply / discharge mechanism unit 3 supplies (conveys) the printing material P0 to a recording position by the ejection head 20, and discharges (conveys) the printed material P0 from the recording position. The ink supply unit supplies ink stored in a storage tank (not shown) to the ejection head 20. The maintenance unit 5 performs maintenance of the ejection head 20 and cleans the ejection head 20.

The supply / discharge mechanism unit 3 includes a supply reel 31, a take-up reel 32, a suction unit 33, an idler roller 37, an idler roller 38, and a Y-axis scanning mechanism 42. The Y-axis scanning mechanism 42 includes two sets of Y-axis guide rails 42a and Y-axis sliders 42b.
The suction unit 33 includes a suction table 33a, a table base 43, a table lifting mechanism, a supply roller 34, a driven roller 34a, a medium feeding roller 36, and a driven roller 36a. Each reel and each roller are rotatable around a rotation axis, and the respective rotation axes are substantially parallel to each other.
The direction in which the printing material P0 is fed is a direction substantially orthogonal to the rotation axes of the reels and rollers that are substantially parallel to each other. A direction parallel to the axial direction of the rotation axis of each reel and each roller is expressed as an X-axis direction, and a feeding direction of the printing material P0 is expressed as a Y-axis direction.

  One Y-axis guide rail 42a of the Y-axis scanning mechanism 42 is disposed on each side in the X-axis direction with the suction table 33a interposed therebetween, and extends in the Y-axis direction. The Y-axis slider 42b is provided on the bottom surface of the table base 43, and is disposed on the Y-axis guide rail 42a in that state. The Y-axis guide rail 42a is configured to slide in the extending direction on the Y-axis guide rail 42a by a Y-axis drive motor (not shown).

  The suction table 33 a of the suction unit 33 is fixed to a table lifting mechanism fixed on the table base 43. The suction table 33a is configured to hold the printing material P0 on its upper surface, and therefore, the upper surface is a surface on the side that holds the printing material P0, that is, a holding surface. Under such a configuration, the UV ink is ejected from the ejection head 20 in a state where the substrate P0 is held on the holding surface, and the ink droplets land on the substrate P0. ing.

The suction table 33a is provided with a suction recess (not shown) consisting of a suction hole or suction groove connected to a negative pressure source (not shown), and the suction recess opens on the holding surface. .
As a result, the printed material P0 is held and fixed on the holding surface by being sucked and sucked by the suction concave portion connected to the negative pressure source in a state where the predetermined portion is positioned on the holding surface. It has become.

  The table lifting mechanism moves the suction table 33a up and down in the Z-axis direction. The suction table 33a is a suction position where the holding surface (suction surface) of the suction table 33a is a predetermined position in the Z-axis direction, and the table base 43 from this suction position. It is moved up and down between the retracted position close to the position and held and fixed at each position. The position of the holding surface of the suction table 33a when in the suction position substantially coincides with the positions of the upper ends of the outer periphery of the supply roller 34 and the outer periphery of the medium feed roller 36, which will be described later. Here, the Z-axis direction refers to the normal direction on the holding surface of the suction table 33a.

  On both sides of the suction table 33a in the Y-axis direction, a supply roller 34 and a driven roller 34a, and a medium feeding roller 36 and a driven roller 36a are disposed. The supply roller 34 and the driven roller 34a, and the medium feeding roller 36 and the driven roller 36a are fixed to the table base 43 via a support member (not shown), and in that state, the suction table 33a is sandwiched on both sides thereof. It is arranged. The supply roller 34 and the driven roller 34a are disposed on the upstream side of the suction table 33a, that is, on the supply reel 31 side, and the medium feed roller 36 and the driven roller 36a are on the downstream side of the suction table 33a, that is, the take-up reel 32. It is arranged on the side.

  The table base 43 can be moved in the Y-axis direction by the Y-axis scanning mechanism 42 and can be held at an arbitrary position in the Y-axis direction. The suction table 33a, the supply roller 34 and the driven roller 34a, the medium feeding roller 36 and the driven roller 36a arranged on the table base 43 are also movable in the Y-axis direction by the Y-axis scanning mechanism 42. And it can hold | maintain in the arbitrary positions in a Y-axis direction.

  The supply reel 31, the idler roller 37, the suction unit 33, the idler roller 38, and the take-up reel 32 included in the supply / discharge mechanism unit 3 are arranged in this order in the Y-axis direction that is the supply direction of the printing material P0. The supply reel 31 side is the upstream side in the supply direction of the printing material P0, and the take-up reel 32 side is the downstream side.

  In the suction unit 33, the supply roller 34 and the driven roller 34a, the suction table 33a, the medium feeding roller 36, and the driven roller 36a are arranged in this order in the Y-axis direction. Therefore, in the supply / discharge mechanism 3, the supply reel 31, the idler roller 37, the supply roller 34 and the driven roller 34a, the suction table 33a, the medium feeding roller 36 and the driven roller 36a, the idler roller 38, and the winding roller The reels 32 are arranged in this order in the Y-axis direction.

  A belt-shaped printed material P0 is wound around the supply reel 31, and the printed material P0 is fed out by rotating the supply reel 31 by a supply motor (not shown). The outer periphery of the driven roller 34a is disposed in contact with the outer periphery of the supply roller 34 and is pressed against the supply roller 34 by an urging device (not shown). The supply roller 34 is rotated by a supply motor (not shown), and the driven roller 34a that is in direct or indirect contact with the supply roller 34 is rotated by the rotation of the supply roller 34. It has become. Under such a configuration, the printing material P0 sandwiched between the supply roller 34 and the driven roller 34a is fed by the rotation of the supply roller 34.

  The idler roller 37 has a rotating shaft that can swing in the Z-axis direction and is biased to one of the swing directions (downward in the present embodiment). The idler roller 37 is brought into contact with the portion of the substrate P0 between the supply reel 31, the supply roller 34, and the driven roller 34a by the urging force. Under such a configuration, the printed material P0 is urged by the idler roller 37, and between the supply reel 31 and the idler roller 37, and between the idler roller 37, the supply roller 34, and the driven roller 34a. The part of is stretched without slack.

  Therefore, it is easy for the printing material P0 to be maintained substantially flat when being supplied and sandwiched between the supply roller 34 and the driven roller 34a. Note that the amount of slack in the portion between the supply reel 31, the supply roller 34, and the driven roller 34a varies depending on the difference between the supply speed of the substrate P0 on the supply roller 34 and the feeding speed of the substrate P0 on the supply reel 31. To do. However, by changing the position of the idler roller 37 following the fluctuation of the slack amount, the tensioned state is maintained without slack. Similarly, the variation in the amount of looseness of the printing material P0 between the supply reel 31, the supply roller 34, and the driven roller 34a due to the movement of the suction unit 33 is also maintained in a tensioned state without any slack. It has become.

  The outer periphery of the driven roller 36a is disposed in contact with the outer periphery of the supply roller 36, and is pressed against the medium feeding roller 36 by an urging device (not shown). The medium feed roller 36 is rotated by a medium feed motor (not shown), and a driven roller 36a that directly or indirectly contacts the medium feed roller 36 is driven by the rotation of the medium feed roller 36. To rotate. Under such a configuration, the printing material P0 sandwiched between the medium feeding roller 36 and the driven roller 36a is fed by the rotation of the medium feeding roller 36.

  Here, the feed amount by the medium feed roller 36 is set to be larger than the feed amount by the supply roller 34. Further, a torque control mechanism (not shown) is incorporated in the power transmission mechanism from the medium feed motor to the medium feed roller 36. Under such a configuration, the printed material P0 that is fed faster than the supply roller 34 by the medium feeding roller 36 is a torque in which the portion between the supply roller 34 and the medium feeding roller 36 is controlled by the torque control mechanism. It is designed to be tensioned according to the tension.

  The holding surface of the suction table 33a faces the stretched portion. That is, the portion of the substrate P0 located on the holding surface of the suction table 33a is stretched with a tension according to the torque controlled by the torque control mechanism. Here, the position of the holding surface of the suction table 33 a located at the above-described suction position substantially coincides with the position of the surface formed by the outer peripheral upper end of the medium feeding roller 36 and the outer peripheral upper end of the supply roller 34. Therefore, the holding surface of the suction table 33a located at the suction position comes into contact with and holds the substrate P0 stretched between the supply roller 34 and the medium feed roller 36.

  The suction table 33a is configured to hold the substrate P0 on its holding surface. The holding surface is a flat surface, and thus the held surface of the printed material P0, that is, the surface opposite to the recording surface is held in a flat state by the holding surface. Although not shown, the holding surface is provided with a suction concave portion including a suction hole or a suction groove, and the target surface of the printed material P0 is sucked by the suction concave portion, and the suction table 33a. It is adsorbed and held on the holding surface. That is, a negative pressure source (not shown) such as a suction pump is connected to the suction concave portion via a pipe or the like, so that the suction concave portion sucks the printing material P0 located on the opening. ing.

The take-up reel 32 is rotated by a take-up motor (not shown), so that the printed material P0 fed from the medium feed roller 36 is taken up by the take-up reel 32. It has become.
The idler roller 38 has a rotating shaft that can swing in the Z-axis direction and is biased in one of the swing directions. Further, the idler roller 38 is brought into contact with the portion between the medium feeding roller 36 and the driven roller 36a and the take-up reel 31 in the substrate P0 by the urging force. Under such a configuration, the printed material P <b> 0 is urged by the idler roller 38, whereby the medium feeding roller 36 and the driven roller 36 a and the take-up reel 31, and the idler roller 38 and the take-up reel 32. The part between is stretched without slack.

  Therefore, the printed material P0 is easily maintained in a substantially flat state when being wound on the take-up reel 32. Note that the amount of slack in the portion between the medium feed roller 36 and the take-up reel 32 depends on the difference between the feed speed of the print target P 0 on the medium feed roller 36 and the take-up speed of the print target P 0 on the take-up reel 32. fluctuate. However, by changing the position of the idler roller 38 following the fluctuation of the slack amount, the tensioned state is maintained without slack. Similarly, the fluctuation of the slack amount of the printing material P0 between the medium feeding roller 36 and the take-up reel 32 due to the movement of the suction unit 33 is also maintained in a tensioned state without slack. ing.

  Under such a state, the printing material P0 is sent from the supply reel 31 to the take-up reel 32 and recorded (printed) on a portion held on the holding surface of the suction table (medium holding unit) 33a. Has been made.

The head mechanism unit 2 includes a head carriage 22 and an X-axis scanning mechanism 11.
The X-axis scanning mechanism 11 includes two sets of an X-axis guide rail 11a, an X-axis slider 11b, and a support base 11d, and four guide rail support columns 11c.
The support base 11d is disposed on each side of the suction table 33a in the X-axis direction with the suction table 33a interposed therebetween, and is located between the pair of Y-axis guide rails 42a and 42a. It is arranged. A maintenance unit 5 is disposed between one Y-axis guide rail 42a and the support base 11d.

  On each of the two support bases 11d and 11d, two guide rail support pillars 11c are erected on each end in the Y-axis direction, one in total. One of the two X-axis guide rails 11a is bridged between the guide rail support pillars 11c erected at the end of the support base 11d on the supply reel 31 side, and above the suction table 33a. It is arranged in a state extending in the X-axis direction. The other of the pair of X-axis guide rails 11a is bridged between the guide rail support columns 11c erected at the end of the support base 11d on the take-up reel 32 side, and the suction table 33a It is arranged in a state extending upward in the X-axis direction.

  The X-axis slider 11b is disposed on the X-axis guide rail 11a, and is configured to slide on the X-axis guide rail 11a in the extending direction by an X-axis drive motor (not shown). Is. Both ends of the bridge plate 27 of the head carriage 22 are fixed to the X-axis slider 11b supported on each of the two X-axis guide rails 11a. The bridge plate 27 having both ends fixed to the X-axis slider 11b is suspended between the two X-axis guide rails 11a while being supported by the X-axis slider 11b. Based on such a configuration, the bridge plate 27 is slid in the extending direction on the X-axis guide rail 11a by the X-axis drive motor, and at an arbitrary position in the X-axis direction. It is supposed to be retained.

  The head carriage 22 includes a bridge plate 27, a sub-carriage 28, and a head unit 21. The sub-carriage 28 is provided at substantially the center of the lower surface of the bridge plate 27, and the head unit 21 is fixed to the lower surface side of the sub-carriage 28. An ejection head 20 is provided on the lower surface side of the head unit 21. Under such a configuration, the ejection head 20 is positioned on the holding surface of the suction table 33a. At this time, the nozzle substrate 25 is opposed to the holding surface.

Here, the suction unit 33 can be moved in the Y-axis direction by the Y-axis scanning mechanism 42, and thus the holding surface of the suction table 33a can be moved in the Y-axis direction. That is, it is possible to scan in the Y-axis direction the part sucked and held on the holding surface of the suction table 33a in the substrate P0.
On the other hand, the ejection head 20 of the head unit 21 fixed to the sub-carriage 28 is scanned in the X-axis direction when the bridge plate 27 provided with the sub-carriage 28 is moved in the X-axis direction by the X-axis scanning mechanism 11. It is supposed to be made.

  Under such a configuration, the X-axis scanning mechanism 11 causes the ejection head 20 of the head unit 21 to scan in the X-axis direction, and the Y-axis scanning mechanism 42 is sucked and held on the holding surface of the suction table 33a on the printed material P0. Can be scanned in the Y-axis direction. That is, the nozzle 24 of the ejection head 20 can be made to face almost the entire surface of the printing material P0 that is sucked and held on the holding surface of the suction table 33a.

  Therefore, the recording portion of the printing material P0 sucked and held on the holding surface of the suction table 33a is moved to the ejection position in the Y axis direction and stopped, and synchronized with the movement of the head unit 21 in the X axis direction. By ejecting UV ink as droplets from the ejection head 20, UV ink droplets (dots) can be arranged at desired positions on the substrate P0. Accordingly, movement in the second direction in which the head unit 21 is moved in the X-axis direction and movement in the first direction in which the printed material P0 sucked and held on the holding surface of the suction table 33a is moved in the Y-axis direction (line feed). Is controlled by the control unit C1 as will be described later, the ejection head 20 of the head unit 21 is made to face an arbitrary position on the substrate P0 held on the holding surface of the suction table 33a, and in this state, the UV Ink can be ejected as droplets. This makes it possible to form (record) a desired image on the substrate P0. In other words, in the present embodiment, UV ink is ejected onto the printing material P0 while the ejection head 20 is repeatedly reciprocated in the second direction (X-axis direction), and the ejection head 20 is moved one way (forward or backward). Each time the movement is made, a line feed is made in the first direction intersecting with the second direction, thereby forming a desired image on the printed material P0.

FIG. 4 is a schematic diagram showing a schematic configuration of the head unit 21 according to the present embodiment. Note that the X-axis and Y-axis shown in FIG. 4 coincide with the X-axis and Y-axis shown in FIG.
As shown in FIG. 4, the head unit 21 has a unit plate 23 attached to the lower surface of the sub-carriage 28, and nine ejection heads 20 mounted on the lower surface side of the unit plate 23. Irradiation devices 80 (fixing control units) for irradiating ultraviolet rays are respectively disposed on both sides of the ejection head 20 in the X-axis direction. In FIG. 4, nine ejection heads 20 are arranged. However, the number of ejection heads 20 is not limited to this, and for example, 15 may be arranged.

  The ejection head 20 is fixed to the unit plate 23 by a holding member (not shown) with the nozzle substrate 25 facing downward. The nine ejection heads 20 are divided in the Y-axis direction to form three head groups 20A each including three ejection heads 20 each. The nozzle row 24A of each ejection head 20 is arranged along the Y-axis direction with the head unit 21 attached to the droplet ejection device 1.

  The three ejection heads 20 constituting one head set 20A are arranged so that the ejection heads 20 of the other ejection head 20 are in the Y axis direction with respect to the nozzles 24 of the ejection heads 20 adjacent to each other. The nozzles 24 at the end are arranged with a shift of one nozzle pitch. In the three jet heads 20 included in the head set 20A under such a configuration, all the nozzles 24 are arranged at an equal pitch in the Y-axis direction when the positions of all the nozzles 24 in the X-axis direction are the same. become. In other words, at the same position in the X-axis direction, the droplets ejected from the nozzles 24 constituting the respective nozzle rows 24A of the respective ejection heads 20 are arranged in a straight line at equal intervals in the Y-axis direction by design. To land.

  Further, in the three head sets 20A included in the head unit 21, all the nozzles 24 are arranged at an equal pitch in the Y-axis direction when the positions of all the nozzles 24 in the X-axis direction are the same. In other words, at the same position in the X-axis direction, the droplets ejected from the nozzles 24 constituting the respective nozzle rows 24A of the respective ejection heads 20 are arranged in a straight line at equal intervals in the Y-axis direction by design. It has come to land. Therefore, the 18 nozzle rows 24A included in the nine ejection heads 20 in the three head sets 20A included in the head unit 21 can be handled as one nozzle row.

  The irradiation device 80 includes an ultraviolet light source (not shown), and is fixed to the sub-carriage 28 or the unit plate 23 with the ultraviolet light source facing downward. As described above, the irradiation device 80 is disposed on each side of the ejection head 20 in the X-axis direction. As a result, immediately after the UV ink is ejected from the ejection head 20 toward the printing material P0, The UV ink that has landed on the printed material P0 can be irradiated with ultraviolet rays. That is, the ejection head 20 ejects UV ink while being scanned in the X-axis direction. Therefore, when the unit plate 23 is scanned in the X-axis direction, the irradiation is performed on the substrate P0 by irradiating the substrate P0 with ultraviolet rays from the irradiation device 80 located on the rear side in the moving direction. It is possible to irradiate the UV ink with ultraviolet rays.

  Here, as the ultraviolet light source, a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, or the like can be used. An LED that emits light in the ultraviolet band can also be used.

FIG. 5 is a plan view showing an ejection surface (lower surface) of the ejection head 20 according to the present embodiment. The X-axis, Y-axis, and (Z-axis) shown in FIG. 5 indicate the state in which the ejection head 20 is incorporated in the droplet ejection device 1. (Z axis).
As shown in FIG. 5, eight nozzle rows 70 are formed. In the present embodiment, these nozzle rows 70 are an image forming ink having a color material, that is, a first nozzle row 71 in which nozzles for ejecting color ink are arranged, and an undercoat or overcoat ink, that is, a color. And a second nozzle row 72 in which nozzles for ejecting clear ink, white ink, or the like without material are arranged.

  Specifically, in order from the left side in FIG. 5, as the first nozzle row 71, the first nozzle row 71C that ejects C (cyan) as a color, the first nozzle row that ejects M (magenta). 71M, the first nozzle row 71Y that ejects Y (yellow), and the first nozzle row 71K that ejects black (K) are arranged one by one. Furthermore, as the second nozzle row 72, two second nozzle rows 72CR for ejecting clear ink for undercoat and two second nozzle rows 72W for ejecting white ink for overcoat are arranged. Yes. However, the present invention is not limited to this arrangement, and other arrangements may be used.

  FIG. 6 is a schematic block diagram illustrating a logical configuration of the control device C1 according to the present embodiment. The control device C1 is mounted on the droplet ejection device 1. However, the present invention is not limited to this, and a part or all of the control device C1 may be provided in a computer device capable of communicating with the droplet ejection device 1. In FIG. 6, the control device C1 includes an image generation unit C111, a color separation processing unit C112, a quantization processing unit C113, a path decomposition unit C114, a dot determination unit C115, a mask information storage unit C116, a mask generation unit C117, and a thinning process. A part C118, an injection control part C119, and a curing control part C120 are included.

The image generation unit C111 receives data representing an image. The image generation unit C111 generates image data for printing by converting data representing the received image. For example, the image generation unit C111 generates image data having pixel values indicating CMYK (cyan, magenta, yellow, black) for each pixel. The image generation unit C111 outputs the generated image data to the color separation processing unit C112 and the dot determination unit C115.
The color separation processing unit C112 generates color separation data for each color of CMYK by performing color separation on the image data input from the image generation unit C111. For example, the color separation processing unit C112 generates cyan color separation data by extracting pixel values indicating cyan from the image data. The color separation processing unit C112 outputs the generated color separation data for each color to the quantization processing unit C113.

The quantization processing unit C113 quantizes the color separation data input from the color separation processing unit C112 to generate quantization data for each color. Specifically, the quantization processing unit C113 converts each pixel value of the color separation data into one of predetermined discrete values that are closest to the pixel value. The quantization processing unit C113 outputs the generated quantized data of each color to the path decomposition unit C114.
The path decomposition unit C114 decomposes the quantized data of each color input from the path decomposition unit C114 into data for each path. Specifically, the pass separation unit C114 extracts data of a set (column) of pixels in the X-axis scanning direction for each dot in the Y-axis scanning direction. The path decomposition unit C114 outputs the quantized data of each pass to the thinning processing unit C118 according to the order of the pass for each color.

The dot determination unit C115 determines whether to print with dots or a group of dots based on the image data input from the image generation unit C111. Specifically, the dot determination unit C115 determines that printing is performed with a dot group when the difference between adjacent pixel values is smaller than a predetermined value. On the other hand, when the difference between adjacent pixel values is equal to or greater than a predetermined value, the dot determination unit C115 determines that printing is performed with dots.
The dot determination unit C115 may determine whether to print with dots or a group of dots for each region. In this case, for example, the dot determination unit C115 calculates the average value of the variance of the pixel values for each region, and if the calculated average value of the variance is smaller than a predetermined value, the region is printed as a dot group. judge. On the other hand, when the average value of the dispersion is equal to or greater than a predetermined value, the dot determination unit C115 determines to print with dots.
The dot determination unit C115 outputs determination information indicating the determination result to the mask generation unit C117.

The mask information storage unit C116 stores mask information. The mask information is information indicating whether or not to eject ink.
The mask generation unit C117 reads the mask information from the mask information storage unit C116 based on the determination information input from the dot determination unit C115. Specifically, when the determination information indicates printing with dots, the mask information storage unit C116 reads out mask information for dots (for example, mask information M11 in FIG. 7). On the other hand, when the determination information indicates that printing is performed with a dot group, the mask information storage unit C116 reads out mask information for the dot group (for example, mask information M12 in FIG. 7). The mask generation unit C117 outputs the read mask information (see FIG. 7) to the thinning processing unit C118.

The thinning processing unit C118 performs a thinning process for thinning the quantized data input from the path decomposition unit C114 based on the mask information input from the mask generation unit C117. Specifically, the thinning processing unit C118 outputs the quantized data corresponding to the position where the mask information is “1” without being masked. The thinning processing unit C118 masks the quantized data corresponding to the position where the mask information is “0”, and sets it to “0”.
The thinning processing unit C118 outputs the data after the thinning processing to the injection control unit C119.

The ejection control unit C119 ejects UV ink as droplets based on the data input from the thinning processing unit C118. Here, when the data is “1”, the ejection control unit C119 ejects UV ink. When the data is “0”, the ejection control unit C119 does not eject UV ink. For example, when mask information for a dot group is input, the ejection control unit C119 ejects each UV ink that forms dots toward a position where the dots are connected to each other.
Further, the injection control unit C119 outputs the input data to the curing control unit C120.

  The curing controller C120 causes the irradiation device 80 to irradiate ultraviolet rays based on the data input from the injection controller C119. For example, the curing control unit C120 starts ultraviolet irradiation when the data becomes “0”. Thereby, for example, when the data is not continuously “0” but the UV ink is continuously ejected, the curing control unit C120 starts the ultraviolet irradiation after the ejection is completed. That is, the UV ink ejected toward a plurality of different points is cured after crossing each other. That is, the irradiation device 80 hardens the ejected ink so that at least two dots are connected and fixed.

The curing control unit C120 may control the timing at which the irradiation device 80 is not irradiated with ultraviolet rays based on the data input from the injection control unit C119. In this case, the curing control unit C120 normally causes the irradiation device 80 to irradiate ultraviolet rays, and starts control not to irradiate ultraviolet rays when the data is other than “0”. In the present embodiment, the case where the curing control unit C120 controls whether or not to irradiate ultraviolet rays has been described. However, the present invention is not limited to this, and ultraviolet rays are based on data input from the injection control unit C119. The intensity of irradiation intensity may be changed.
Further, the curing control unit C120 may change the intensity of the ultraviolet irradiation intensity according to the time required until the UV ink is cured and the intensity of the ultraviolet light. Further, the curing control unit C120 may not perform the above control. For example, when the time for curing the UV ink is longer than the movement time of the ejection head 20 (for example, the movement time when moving by one dot in the X-axis direction), the curing control unit C120 performs control. Even without this, at least two dots can be connected and fixed.

FIG. 7 is a schematic diagram illustrating an example of mask information output by the mask generation unit C117 according to the present embodiment. In FIG. 7, mask information M1 and M11 are dot mask information, and mask information M12 is dot group mask information.
FIG. 7A shows mask information when printing using dots is performed without printing using dots. FIG. 7A shows that “1000” as the mask information M11 is repeatedly output.
FIG. 7B shows mask information when printing is performed using both dots and dot groups. The mask information M12 for the dot group is “1100”, for example, and “1” is continuous. In this case, for example, as shown in FIG. 2, UV ink is ejected toward points separated by an interval a, and ultraviolet rays are irradiated after ejection toward at least two points.

FIG. 8 is a flowchart showing an example of the operation of the droplet ejecting apparatus 1 according to the present embodiment.
(Step S <b> 101) The droplet ejecting apparatus 1 determines whether or not to print with a dot group. If it is determined to print with a dot group (YES), the process proceeds to step S121. On the other hand, if it is not determined to print with a dot group (NO), the process proceeds to step S111.

(Step S111) The droplet ejecting apparatus 1 ejects (discharges) the first dots. The first dot is, for example, the dot I12 in FIG. Thereafter, the process proceeds to step S112.
(Step S112) The droplet ejecting apparatus 1 determines whether or not the time t1 has elapsed. The time t1 is related to the time for the UV ink to spread before curing starts. The time t1 is related to the size (height or radius) of each direction of the dot, for example. For example, a dot with a high height and a small radius is associated with a shorter time t1 compared to a dot with a low height and a large radius. The droplet ejecting apparatus 1 may store a plurality of candidates for a time t1 in advance, and control the size of the dot by selecting the time t1 from the candidates. When it is determined that the time t1 has elapsed (YES), the process proceeds to step S113. On the other hand, when it is determined that the time t1 has not elapsed (NO), the process returns to step S112.

(Step S113) The droplet ejecting apparatus 1 starts irradiation with ultraviolet rays. Thereafter, the process proceeds to step S114.
(Step S114) The droplet ejection device 1 determines whether or not the time t2 has elapsed. The time t2 is related to the time during which the UV ink spreads from the start of curing to the curing. The time t2 is related to the size of each direction of the dots, for example. For example, a dot with a high height and a small radius is associated with a shorter time t2 compared to a dot with a low height and a large radius. The droplet ejecting apparatus 1 may store a plurality of candidates for time t2 in advance, and control the dot size by selecting the time t2 from the candidates. When it is determined that the time t2 has elapsed (YES), the process proceeds to step S131. On the other hand, when it is determined that the time t2 has not elapsed (NO), the process returns to step S114.

(Step S121) The droplet ejecting apparatus 1 ejects the first dot. The first dot is, for example, UV ink ejected toward the center 131 (see FIG. 2). Thereafter, the process proceeds to step S122.
(Step S122) The droplet ejecting apparatus 1 ejects the second dot. The second dot is, for example, UV ink ejected toward the center 132 (see FIG. 2). Thereafter, the process proceeds to step S123.

(Step S123) The droplet ejection device 1 determines whether or not the time t3 has elapsed. The time t3 is related to the time for the UV ink to spread before curing starts. The time t3 is related to, for example, the size of each dot group in each direction and how the dots in the dot group are connected. The droplet ejecting apparatus 1 may store a plurality of candidates for the time t3 in advance, and control the size of the dots by selecting the time t3 from the candidates. When it is determined that the time t3 has elapsed (YES), the process proceeds to step S124. On the other hand, when it is determined that the time t3 has not elapsed (NO), the process returns to step S123.

(Step S124) The droplet ejecting apparatus 1 starts irradiation with ultraviolet rays. Thereafter, the process proceeds to step S125.
(Step S125) The droplet ejection device 1 determines whether or not the time t4 has elapsed. The time t4 is related to the time during which the UV ink spreads from the start of curing to the curing. The time t4 is related to, for example, the size of each dot group in each direction and how the dots in the dot group are connected. The droplet ejecting apparatus 1 may control the size of the dots by storing a plurality of candidates for a time t4 in advance and selecting the time t4 from the candidates. When it is determined that the time t4 has elapsed (YES), the process proceeds to step S131. On the other hand, when it is determined that the time t4 has not elapsed (NO), the process returns to step S125.

(Step S131) The droplet ejecting apparatus 1 determines whether or not the processing for one pass has been completed. If it is determined that the process for one path has not been completed (NO), the process returns to step S101. On the other hand, if it is determined that the processing for one path has been completed (YES), the process proceeds to step S132.
(Step S132) The droplet ejecting apparatus 1 determines whether or not the processing has been completed for all passes of the image to be printed. If it is determined that there is a path that has not been processed (NO), the process returns to step S101. On the other hand, when it is determined that the processing has been completed for all paths (YES), the operation of FIG. 8 is terminated.

  FIG. 9 is a plan view showing the movement of the ejection surface (lower surface) of the ejection head 20 according to the present embodiment. The ejection head 20 ′ is the one when the ejection head 20 has moved by a distance a in the X-axis direction. The ejection head 20 can eject dots at an interval of the distance a. That is, when “1” continues in the mask information, for example, UV ink is ejected at the time of the ejection head 20 and the time of the ejection head 20 ′. Thereby, the UV ink is ejected to the center separated by the distance a, and the UV inks intersect each other. When the UV ink is cured, a dot group is formed.

Thus, according to the present embodiment, the droplet ejecting apparatus 1 prints dots that protrude from the surface of the substrate P0. The droplet ejecting apparatus 1 prints an image including a dot group in which at least two dots are connected. For example, the droplet ejecting apparatus 1 ejects each ink that forms a dot toward a position where the dots are connected to each other.
Thereby, at least one of the dots in the dot group is connected to the other dots, so that the height from the printing material P0 is lower than that in the case where the dots are not connected to the other dots. Therefore, the droplet ejecting apparatus 1 can adjust the height of the dots protruding from the substrate P0, and can improve the printing quality. Further, for example, the droplet ejecting apparatus 1 can reduce banding caused by surface irregularities. In addition, for example, the droplet ejecting apparatus 1 can adjust the graininess by adjusting the height and the dot spread by the dot group. Moreover, the droplet ejecting apparatus 1 can adjust the roughness of the image.

  Further, according to the present embodiment, the irradiation device 80 solidifies the ink ejected by the ejection head 20 so that at least two dots are connected and fixed. Since the two dots are connected and fixed, the droplet ejecting apparatus 1 can adjust the height of the dots protruding from the substrate P0 and improve the printing quality.

(Modification)
In the above embodiment, an example in which a plurality of dots in the X-axis scanning direction forms a dot group has been described. However, the present invention is not limited to this, and a plurality of dots in the Y-axis direction may form a dot group. A plurality of dots in both the X-axis direction and the Y-axis direction may form a dot group.

FIG. 10 is a schematic diagram illustrating an example of mask information output by the mask generation unit C117 according to the modification of the present embodiment. In FIG. 7, mask information M2 and M22 are mask information for dots, and mask information M21 is mask information for dot groups.
FIG. 10A shows mask information when printing using dots is performed without printing using dots. FIG. 10A shows that “1000” is repeatedly output in the first and fifth paths on the Y axis. FIG. 10A shows that “0000” is repeatedly output in the second to fourth paths on the Y-axis.

FIG. 10B shows mask information when printing is performed using both dots and dot groups. FIG. 10B shows that “1000” is repeatedly output in the first and fifth passes on the Y axis. In the second pass on the Y axis, the mask information M21 for the dot group is, for example, “1000”. As a result, “1” continues in the Y-axis direction in the first and second passes on the Y-axis. That is, a plurality of dots in the Y-axis direction form a dot group.
On the other hand, the mask information M22 for dots is, for example, “0000”. In this case, “1” does not continue in the Y-axis direction in the first and second passes on the Y-axis. Dots are formed in the Y-axis direction.
In this modification, ultraviolet light is irradiated after the UV ink is ejected in a plurality of passes. For example, the droplet ejecting apparatus 1 irradiates ultraviolet rays every four passes.

FIG. 11 is a schematic diagram showing dots I22 and I23 and dot groups I21 and I24 according to this modification. The X axis, Y axis, and Z axis in FIG. 11 are the same as those in FIG. Here, the Y axis is graduated for each distance b.
In FIG. 11, for simplicity of explanation, the amount of UV ink per drop is the same, the dots I22 and I23 are formed with one drop of UV ink, and the dots I21 and I24 are formed with two drops of UV ink. And However, the present invention is not limited to this, and the amount of UV ink per droplet may be different.

Fig.11 (a) is a top view at the time of observing the printing surface (XY plane) of printed matter P1 facing a printing surface. The dot I22 is circular. The dot group I21 is oval. In the dot group I21, the UV ink ejected toward the center 221 and the UV ink ejected toward the center 222 intersect and are then cured.
For example, the distance between the center 221 and the center 222 (“b” in FIG. 11A) is smaller than 2r (a <2r). That is, at least a part of the circle at the center 221 and the circle at the center 222 intersect. For this reason, the UV ink ejected toward two points intersect to form a dot group I21.

  FIG. 11B is a B-B ′ cross-sectional view of FIG. 11A and an XZ plan view. In FIG. 11B, the dots I22 and I23 and the dot groups I21 and I24 are fixed in a state of protruding from the substrate P0. Here, the height protruding from the substrate is T1 at the dot I22. On the other hand, the height of the dot group I21 is T2. Here, T2 is smaller than T1, that is, the heights of the dot groups I21 and I24 are lower than the heights of the dots I22 and I23.

  In the above embodiment, the times t1 and t3, and t2 and t4 may be the same time or different times. For example, the droplet ejecting apparatus 1 may start irradiation with ultraviolet rays earlier than t1> t3, that is, in the case of a dot group, as compared with the case of a dot. Further, for example, the droplet ejecting apparatus 1 may irradiate with ultraviolet rays at t2 <t4, that is, in the case of a dot group, which is longer than that in the case of dots.

  In the above-described embodiment, in the droplet ejecting apparatus 1, the mask information storage unit C116 may store only mask information for dots, and the mask generation unit C117 may generate mask information for dot groups. That is, the mask generation unit C117 may generate the mask information for the dot group by expanding the information (“1”) indicating that no masking is performed (for example, “1000” is “1100”).

In addition, you may make it implement | achieve a part of control apparatus C1 in embodiment mentioned above with a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. Here, the “computer system” is a computer system built in the control device C1, and includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
Moreover, you may implement | achieve part or all of the control apparatus C1 in embodiment mentioned above as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the control device C1 may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

  DESCRIPTION OF SYMBOLS 1 ... Droplet injection apparatus, 3 ... Supply / discharge mechanism part, 5 ... Maintenance part, 20 ... Injection head (injection part), 21 ... Head unit, 24 ... Nozzle, 80 ... irradiation device, C1 ... control device, C111 ... image generation unit, C112 ... separation processing unit, C113 ... quantization processing unit, C114 ... pass decomposition unit, C115 ... -Dot determination unit, C116 ... mask information storage unit, C117 ... mask generation unit, C118 ... thinning processing unit, C119 ... injection control unit, C120 ... curing control unit, I11, I12 , I22, I23 ... dot, I13, I14, I15, I21, I24 ... dot group, P1 ... printed material, P0 ... printed material

Claims (5)

A droplet ejecting apparatus that prints dots protruding from the surface of a substrate,
An image generator that converts data representing the received image to generate image data for printing;
A dot determination unit that determines whether to print with dots or a group of dots based on the image data for printing generated by the image generation unit;
A mask information storage unit in which the first mask information and the second mask information are stored;
Based on the determination result of the dot determination unit, a mask generation unit that reads mask information from the mask information storage unit,
With
The dot determination unit calculates an average value of dispersion of pixel values for each area, and determines that the area is printed as a dot group when the calculated average value of dispersion is smaller than a predetermined value. If the average value of the variance is greater than the predetermined value, it is determined that the area is printed with dots,
The mask generation unit reads the first mask information from the mask information storage unit when the dot determination unit determines to print with the dots, and when the dot determination unit determines to print with the dot group , Reading the second mask information from the mask information storage unit,
The first mask information is mask information for performing printing using only the dots without including a dot group in which at least two dots are connected .
The droplet ejecting apparatus, wherein the second mask information is mask information for performing printing using both the dot and the dot group .   The droplet ejecting apparatus according to claim 1, further comprising: an ejecting unit that ejects each of the inks forming the dots toward a position where the dots are connected to each other.   The liquid droplet according to claim 2, wherein at least one of the dots in the dot group is connected to another dot, so that the height from the printed material is lower than that in a case where the dot is not connected to another dot. Injection device. Such that at least two of the dots is fixed connected, liquid-droplet jetting apparatus according to claim 2 or 3 comprising a fixing control unit solidify ink the ejection portion is injected. A printing image data generation process for converting the data representing the received image to generate printing image data;
A dot determination process for determining whether to print with dots or to print with a group of dots based on the printing image data generated in the printing image data generation step;
Based on the determination result of the dot determination process, a mask generation process for reading out mask information used when printing the image data for printing from a mask information storage unit,
An ejection process of ejecting each of the inks forming the dots based on the mask information toward a position where the dots protruding from the surface of the printed material are formed ;
A fixing control process for solidifying the ink ejected in the ejection process;
I have a,
In the dot determination step, an average value of dispersion of pixel values is calculated for each region, and when the calculated average value of dispersion is smaller than a predetermined value, it is determined that the region is printed as a dot group. If the average value of the variance is greater than the predetermined value, it is determined that the area is printed with dots,
In the mask generation process, when the dot determination unit determines to print with the dots, the mask information storage unit does not include a dot group in which at least two dots are connected, and prints using only the dots. While reading the mask information as mask information to be used in the ejection process, when the dot determination unit determines to print with the dot group, printing using both the dot and the dot group is performed from the mask information storage unit. A printing method for reading out mask information to be used as mask information used in the ejection process .

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