JP5861265B2 - Droplet ejecting apparatus and droplet ejecting method - Google Patents

Description

  The present invention relates to a droplet ejecting apparatus and a droplet ejecting method.

  The droplet ejecting apparatus includes an ejecting head in which nozzles for ejecting ink are formed. By relatively moving the ejecting head and the ejected object, the ink is ejected and arranged in a wide range of the ejected object.

In such a droplet ejecting apparatus, for example, as shown in Patent Document 1 and Patent Document 2, an inspection unit for inspecting an ink ejecting state of a nozzle is installed.
The droplet ejecting device is configured to recover the ink ejecting state of the nozzle by performing cleaning or the like on the nozzle when the inspection unit detects that the ink ejecting state of the nozzle is abnormal. Yes.

JP 2006-76067 A JP 2009-255086 A

Incidentally, in the inspection unit, ink is ejected to the inspection ejection unit, and the landed ink is imaged. The ink ejection state is performed based on the captured image data.
However, the ink ejected to the inspection ejection unit may be difficult to detect in the image processing, and the ink ejection state may be misidentified.
In particular, in recent years, clear ink for overcoating or undercoating is sometimes used, making it difficult to detect ink.

  SUMMARY An advantage of some aspects of the invention is that it provides a droplet ejecting apparatus and a droplet ejecting method capable of reliably detecting ink in an inspection unit.

  As means for solving the above problems, the present invention adopts the following configuration.

  According to a first aspect of the present invention, there is provided an ejection head having a nozzle that ejects ink onto an ejection target, and an inspection unit that receives the ink outside the ejection target and inspects the ink ejection state of the nozzle. In the liquid droplet ejecting apparatus, a configuration is adopted in which a region to be ejected in which the ink is ejected in the inspection unit has liquid repellency with respect to the ink.

According to the present invention employing such a configuration, since the ejected area of the inspection unit has liquid repellency, the ink ejected to the inspection unit approaches a spherical shape, and the height of the ink increases. Even if it is a clear ink, it is not completely transparent, so that it becomes difficult for light to pass through as the height of the ink increases. That is, as the ink height increases, the difference in density between the area where the ink exists and the surrounding area increases. Therefore, the ejected area of the inspection unit has liquid repellency, and the height of the ink ejected onto the ejected area increases, so that ink can be detected easily and reliably.
Therefore, according to the present invention, it is possible to reliably detect ink in the inspection unit.

  A second invention is an ultraviolet curable ink in which the ink is cured by ultraviolet irradiation in the first invention, and the ink is applied before the ink ejection for inspecting the ink ejection state of the nozzle. A configuration is adopted in which the ink is ejected onto the ejection region, and the ejected ink is cured to control to impart liquid repellency to the ejected region.

The ultraviolet curable ink exhibits liquid repellency with respect to the ink before being cured by being cured by being irradiated with ultraviolet rays.
For this reason, according to the present invention employing the above-described configuration, it is possible to impart liquid repellency to the ejected area even when the ejected area does not have ink liquid repellency in advance. .

  According to a third invention, in the second invention, the nozzles eject a first color ink as the ink, and a second nozzle ejects a second color ink as the ink. When the liquid-repellent property is imparted to the ejected area, a configuration is adopted in which control is performed to eject the first color ink and the second color ink to the ejected area.

  According to the present invention employing such a configuration, since ink is ejected from a large number of nozzles to the ejected area at a time, liquid repellency can be imparted to the ejected area in a short time. It becomes.

  According to a fourth aspect, in the second aspect, the nozzle includes a third nozzle that ejects a clear ink as the ink, and the clear ink is added to the ejected region when the liquid ink has liquid repellency. A configuration is adopted in which control is performed to inject into the injection target region.

  When the ultraviolet curable ink is cured, it exhibits strong liquid repellency with respect to the same kind of ink before being cured. In a liquid droplet ejecting apparatus using clear ink, the most difficult to detect by image processing is clear ink having a large light transmittance. However, according to the present invention, the ejected region has a large liquid repellency relative to the clear ink. Therefore, clear ink can be detected more reliably.

  According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the ink is ejected onto the ejected object at a moving speed of the ejecting head when imparting liquid repellency to the ejected area. A configuration is adopted in which control is performed to make the control speed slower than the moving speed of the ejection head.

According to the present invention adopting such a configuration, since the moving speed of the ejection head when imparting liquid repellency to the ejected area becomes slow, the jet head is ejected to impart liquid repellency to the ejected area. The time until the ink is irradiated with ultraviolet rays becomes longer, and the ink can be spread over a wide range.
For this reason, it is possible to dispose ink over the entire area to be ejected with a small amount of ink.

  According to a sixth invention, in any one of the second to fifth inventions, the ink is ejected from the nozzle to the ejected object while the ejecting head is repeatedly reciprocated in the main scanning direction. The ink is ejected onto the ejected area during the first reciprocal movement, and the ultraviolet light is irradiated onto the ink ejected onto the ejected area during the second and subsequent reciprocating movements of the ejection head. Therefore, a configuration is adopted in which control for imparting liquid repellency to the sprayed region is performed.

According to the present invention employing such a configuration, since the ink is irradiated with ultraviolet rays during the second and subsequent reciprocating movements of the ejecting head, the liquid repellency is maintained until the ejecting head reciprocates at least once. The ink ejected to impart the property is not irradiated with ultraviolet rays, and it is possible to secure a time for the ink to spread.
Accordingly, it is possible to dispose ink over the entire area to be ejected with a small amount of ink.

  According to a seventh invention, in any one of the second to sixth inventions, the ejection resolution of the ink at the time of imparting liquid repellency to the ejected area is determined when the ink ejection state of the nozzle is inspected. A configuration is adopted in which control is performed so that the resolution and the jetting resolution at the time of jetting the ink are coarser than the jetting target.

  According to the present invention employing such a configuration, the amount of ink required to impart liquid repellency can be reduced.

  According to an eighth invention, in any one of the second to seventh inventions, the landing diameter of the ink when imparting liquid repellency to the ejected area is set as the landing diameter of the ink on the ejected object and the nozzle. A configuration is adopted in which control is performed to make the diameter larger than the landing diameter when the ink ejection state is inspected.

According to the present invention employing such a configuration, the landing diameter of ink when imparting liquid repellency is increased, and therefore the number of inks ejected when imparting liquid repellency can be reduced.
For this reason, it is possible to complete the ejection of ink for imparting liquid repellency in a shorter time.

  In a ninth aspect of the present invention, in any one of the first to eighth aspects, a configuration is adopted in which control is performed to eject ink a plurality of times at the same position of the inspection section when the ink ejection state of the nozzle is inspected. .

  According to the present invention employing such a configuration, when the ink ejection state is inspected, the ink ejected later overlaps the ink ejected earlier, so that the height of the ink in the inspection unit is increased. This makes it possible to detect ink more easily and reliably.

  According to a tenth aspect of the present invention, in any one of the first to eighth aspects, the control is performed to eject ink from a single nozzle to a different position of the inspection unit when inspecting the ink ejection state of the nozzle. Is adopted.

  According to the present invention employing such a configuration, it is possible to determine the ink ejection state inspection for a single nozzle from the ink ejected to a plurality of locations in the inspection unit. For this reason, it is possible to more reliably determine the ink ejection state.

  An eleventh invention adopts a configuration in which control is performed so that ink ejected from a single nozzle is connected linearly in the ejected area in the tenth invention.

  According to the present invention employing such a configuration, since the ink ejected from a single nozzle is linearly connected in the inspection section, the ink ejected from the nozzle is not connected to other ink. Thus, it is possible to easily detect ink by image processing.

  In a twelfth aspect of the invention according to any one of the first to eleventh aspects of the invention, the width of the ejected region is set to be twice or more the landing diameter of the ink ejected when the ink ejection state of the nozzle is inspected. Adopted the configuration that is.

  According to the present invention employing such a configuration, it is possible to prevent a portion of the ink ejected when inspecting the ink ejection state from exceeding the ejected region and to inspect the ink ejection state. Can be reliably arranged in the injection region.

  In a thirteenth aspect of the invention, the ink is ejected from the nozzles formed on the ejection head to the ejected object, and the ink is applied to the inspection unit provided outside the ejected object. Is a liquid droplet ejecting method for inspecting the ink ejection state of the nozzles, and adopts a configuration in which a region to be ejected in which the ink is ejected in the inspection unit has liquid repellency with respect to the ink. .

  According to the present invention employing such a configuration, since the ejected area of the inspection unit has liquid repellency, the ink ejected to the inspection unit approaches a spherical shape, and the height of the ink increases. Even if it is a clear ink, it is not completely transparent, so that it becomes difficult for light to pass through as the height of the ink increases. That is, as the ink height increases, the difference in density between the area where the ink exists and the surrounding area increases. Therefore, the ejected area of the inspection unit has liquid repellency, and the height of the ink ejected onto the ejected area increases, so that ink can be detected easily and reliably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a schematic configuration of a droplet ejecting apparatus according to an embodiment of the present invention, where (a) is a plan view of the droplet ejecting apparatus and (b) is a side view of the droplet ejecting apparatus. (A)-(c) is a figure which shows schematic structure of an ejection head. It is a top view which shows the ejection surface (lower surface) of an ejection head. It is a bottom view which shows schematic structure of a head unit. It is a schematic diagram containing the test | inspection part 6 with which the droplet ejecting apparatus in 1st Embodiment of this invention is provided. It is a schematic diagram for demonstrating operation | movement of the droplet ejecting apparatus of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a droplet ejecting apparatus and a droplet ejecting method according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

1A and 1B are schematic views showing a schematic configuration of a first embodiment of a droplet ejecting apparatus according to the present invention, wherein FIG. 1A is a plan view of the droplet ejecting apparatus, and FIG. FIG. 3 is a side view of the droplet ejecting apparatus. FIGS. 1A and 1B show a case where the droplet ejecting apparatus of the present invention is applied to a printing apparatus that performs printing on a continuous long recording medium 10 (an ejected object). ing. In FIGS. 1A and 1B, reference numeral 1 denotes a droplet ejecting apparatus. The droplet ejecting apparatus 1 includes an ejecting head 20 that ejects droplets of ultraviolet curable ink as ink, and an ejecting head 20. An irradiation device 80 (see FIG. 4) for irradiating the ejected ultraviolet curable ink S (see FIG. 6 and the like) with ultraviolet rays is provided.
The droplet ejecting apparatus 1 according to the present embodiment includes a head mechanism unit 2 having an ejecting head 20, a supply / discharge mechanism unit 3, an ink supply unit (not shown), a maintenance unit 5, and an inspection unit 6. , And a control unit 60.

  The ejection head 20 is an inkjet ejection head, and includes an ink containing an ultraviolet curable component, that is, an ultraviolet curable ink S as droplets, and a recording portion of a continuous long band-shaped recording medium 10. It is sprayed toward the surface. Here, as the recording medium 10, a medium capable of recording with the ultraviolet curable ink S is used in this embodiment, and specifically, polyethylene terephthalate (PET), polyethylene (PE), polycarbonate (PC), or the like is used. A flexible film is used.

  The supply / discharge mechanism 3 supplies the recording medium 10 to a recording position by the ejection head 20 and discharges the recording medium 10 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. In this embodiment, the maintenance unit 5 recovers the nozzle ejection state by cleaning 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 44, 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 recording medium 10 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 recording medium 10 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 slider 42b is moved on the Y-axis guide rail 42a by a Y-axis drive motor (not shown). It is configured to slide in the extending direction.

  The suction table 33 a of the suction unit 33 is fixed to a table lifting mechanism 44 fixed on the table base 43. The suction table 33a is configured to hold the recording medium 10 on the upper surface thereof, and therefore, the upper surface is a surface on the side that holds the recording medium 10, that is, a holding surface. Under such a configuration, the ultraviolet curable ink S is ejected from the ejection head 20 in a state where the recording medium 10 is held on the holding surface, and droplets of the ink land on the recording medium 10. It is like that.

  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 recording medium 10 is held and fixed on the holding surface by being sucked and sucked by the suction recess connected to the negative pressure source in a state where the predetermined portion is positioned on the holding surface. It has become.

  The table raising / lowering mechanism 44 raises and lowers the suction table 33a in the Z-axis direction. The holding position (suction surface) of the suction table 33a becomes a predetermined position in the Z-axis direction, and the table base from the suction position. It is moved up and down between the retreat positions close to 43 and is 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.

  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, which is the supply direction of the recording medium 10. The supply reel 31 side is the upstream side in the supply direction of the recording medium 10, 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 recording medium 10 is wound around the supply reel 31, and the recording medium 10 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 recording medium 10 sandwiched between the supply roller 34 and the driven roller 34 a 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 recording medium 10 between the supply reel 31, the supply roller 34, and the driven roller 34a by the urging force. Under such a configuration, the recording medium 10 is urged by the idler roller 37, so that it is 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, the state when the recording medium 10 is supplied and sandwiched between the supply roller 34 and the driven roller 34a is easily maintained substantially flat. 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 recording medium 10 in the supply roller 34 and the feeding speed of the recording medium 10 in 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 fluctuation of the slack amount of the recording medium 10 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 recording medium 10 sandwiched between the medium feeding roller 36 and the driven roller 36 a 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 recording medium 10 that is fed faster than the supply roller 34 by the medium feed roller 36 has a torque controlled by the torque control mechanism at a portion between the supply roller 34 and the medium feed roller 36. It is designed to be tensioned according to the tension.

  The holding surface of the suction table 33a faces the stretched portion. That is, a portion of the recording medium 10 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 is in contact with and holds the recording medium 10 stretched between the supply roller 34 and the medium feed roller 36.

  The suction table 33a is configured to hold the recording medium 10 on its holding surface. The holding surface is a flat surface. Therefore, the surface to be held in the recording medium 10, that is, the surface opposite to the surface to be recorded is held flat 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. The suction surface is used to suck the holding surface of the recording medium 10, 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 recording medium 10 located on the opening. ing.

The take-up reel 32 is rotated by a take-up motor (not shown), so that the recording medium 10 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. The idler roller 38 is brought into contact with the portion of the recording medium 10 between the medium feeding roller 36 and the driven roller 36 a and the take-up reel 31 by the urging force. Under such a configuration, the recording medium 10 is urged by the idler roller 38, so that the medium feeding roller 36, 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 recording medium 10 is easily maintained in a substantially flat state when being wound on the take-up reel 32. 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 recording medium 10 at the medium feed roller 36 and the take-up speed of the recording medium 10 at 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 recording medium 10 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 recording medium 10 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 portion) 33a in the middle. 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, and a nozzle substrate 25 on which nozzles 24 are formed is disposed on the bottom side of the ejection head 20 as shown in FIG. . 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 the portion of the recording medium 10 held by suction on the holding surface of the suction table 33a in the Y-axis direction.
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.
In the present embodiment, the inspection unit 6 is installed on the −X direction side of the suction table 33a. In the X-axis scanning mechanism 11, the length of the X-axis guide rail 11a is set so that the ejection head 20 can reach an inspection ejection unit 61 of the inspection unit 6 described later.

  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 suctions and holds the suction head 33 on the holding surface of the suction table 33a. 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 recording medium 10 held by the holding surface of the suction table 33a.

  Therefore, the recording target portion of the recording medium 10 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 the ultraviolet curable ink S as droplets from the ejection head 20, the droplets (dots) of the ultraviolet curable ink S can be arranged at desired positions on the recording medium 10. Therefore, main scanning for moving the head unit 21 in the X-axis direction and sub-scanning (line feed) for moving the recording medium 10 sucked and held on the holding surface of the suction table 33a in the Y-axis direction are controlled as described later. By controlling by the unit 60, the ejection head 20 of the head unit 21 is opposed to an arbitrary position on the recording medium 10 held on the holding surface of the suction table 33a, and in this state, the ultraviolet curable ink S is used as a droplet. Can be injected. As a result, a desired image can be formed (recorded) on the recording medium 10. That is, in the present embodiment, the ultraviolet curable ink S is ejected onto the recording medium 10 while the ejecting head 20 is repeatedly reciprocated in the main scanning direction (X direction), and the ejecting head 20 is moved one way (forward movement). Each time the recording medium 10 is moved backward, the recording medium 10 is turned in the sub-scanning direction, thereby forming a desired image on the recording medium 10.

  Next, the ejection head 20 will be described with reference to FIGS. 2 (a) to 2 (c) and FIG. 2A to 2C are diagrams illustrating a schematic configuration of the ejection head 20, FIG. 2A is an external perspective view illustrating a schematic configuration of the ejection head 20, and FIG. 2B is an internal structure of the ejection head 20. FIG. 4C is a main part perspective view illustrating the nozzle part of the ejection head 20. FIG. 3 is a plan view showing an ejection surface (lower surface) of the ejection head 20, and is a diagram for explaining a schematic configuration of the nozzle row. 2A and 3, the X axis, the Y axis, and the Z axis indicate the state in which the ejection head 20 is incorporated in the droplet ejection apparatus 1. Are coincident with the X axis, the Y axis, and the (Z axis).

  As shown in FIG. 2A, the ejection head 20 is formed with a nozzle substrate 25, and a large number of nozzles 24 are linearly arranged on the nozzle substrate 25 along the Y-axis direction. A plurality of nozzle rows 70 are formed in the X-axis direction. In the present embodiment, eight nozzle rows 70 are formed as shown in FIG. 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. 3, as the first nozzle row 71, a first nozzle row 71C that ejects C (cyan) as color ink, and a first nozzle that ejects M (magenta). The rows 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. That is, in the present embodiment, the number of the second nozzle rows 72CR and 72W is larger than the number of the first nozzle rows 71C, 71M, 71Y, and 71K that eject the color ink.

  Here, in FIG. 3, odd-numbered nozzle rows from the left side, that is, the first first nozzle row 71C, the third first nozzle row 71Y, the fifth second nozzle row 72CR, and the seventh first nozzle row 71CR. In the second nozzle row 72W, the positions of the corresponding nozzles 24 in the Y-axis direction are the same between the nozzle rows, and the intervals between the nozzles 24 along the Y-axis direction are all the same. Accordingly, the nozzles 24 in each nozzle row are arranged at an equal pitch. Similarly, in FIG. 3, the even-numbered nozzle rows from the left side, that is, the second first nozzle row 71M, the fourth first nozzle row 71K, the sixth second nozzle row 72CR, and the eighth eighth nozzle row. In the second nozzle row 72W, the positions of the corresponding nozzles 24 in the Y-axis direction are the same between the nozzle rows, and the intervals between the nozzles 24 along the Y-axis direction are all formed and arranged the same. Accordingly, the nozzles 24 in each nozzle row are arranged at an equal pitch.

However, two nozzle rows adjacent in the X-axis direction, for example, between the first nozzle row 71C and the first nozzle row 71M, between the first nozzle row 71Y and the first nozzle row 71K, Between the second nozzle rows 72CR and between the two second nozzle rows 72W, the positions of the nozzles 24 are staggered with a half-pitch shift in the Y-axis direction.
Note that each of the nozzle rows 71 and 72 is formed by arranging 180 nozzles 24 in this embodiment.
Then, the ultraviolet curable ink S is ejected as droplets from the nozzle 24 and landed on the surface of the opposing recording medium 10, so that the ejection head 20 is placed at a desired position on the recording medium 10. S can be arranged.

  As shown in FIGS. 2B and 2C, the ejection head 20 is obtained by laminating a pressure chamber plate 51 on a nozzle substrate 25 and further laminating a diaphragm 52 on the pressure chamber plate 51. The pressure chamber plate 51 is formed with a liquid pool 55 that is always filled with the ultraviolet curable ink S supplied to the ejection head 20. The liquid pool 55 includes the vibration plate 52, the nozzle substrate 25, and a wall ( (Not shown). The ultraviolet curable ink S is supplied to the liquid pool 55 via the liquid supply hole 53 of the vibration plate 52. The pressure chamber plate 51 is formed with a pressure chamber 58 partitioned by a plurality of head partition walls 57.

  The pressure chambers 58 are provided corresponding to the respective nozzles 24, and the number of the pressure chambers 58 and the number of the nozzles 24 are the same. A functional liquid is supplied to the pressure chamber 58 from a liquid pool 55 through a supply port 56 positioned between the two head partition walls 57. A set of the pressure chamber 58, the nozzle 24, and the supply port 56 of the head partition wall 57 is arranged in a line along the liquid pool 55, and the nozzles 24 arranged in a line form a nozzle line 24A. Although not shown in FIG. 2B, another nozzle row 24 </ b> A is formed on the side of the nozzle row 24 </ b> A including the nozzles 24.

  As shown in FIG. 2C, piezoelectric elements 59 are arranged on the diaphragm 52 corresponding to the respective pressure chambers 58, that is, corresponding to the individual nozzles 24. The piezoelectric element 59 has a piezoelectric layer sandwiched between a lower electrode and an upper electrode. When a driving waveform (driving voltage) is applied between the electrodes, the ultraviolet curable ink S is ejected from the corresponding nozzle 24. It is supposed to let you. Here, the piezoelectric element 59 is controlled by the control unit 60 shown in FIGS. 1 (a) and 1 (b).

Next, a schematic configuration of the head unit 21 provided in the head mechanism unit 2 will be described with reference to FIG. FIG. 4 is a bottom view showing a schematic configuration of the head unit 21. 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 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. 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 ultraviolet curable ink S is ejected from the ejection head 20 toward the recording medium 10. In addition, the ultraviolet curable ink S landed on the recording medium 10 can be irradiated with ultraviolet rays. That is, the ejection head 20 ejects the ultraviolet curable ink S while being scanned (main scanning) in the X-axis direction. Therefore, when the unit plate 23 is scanned in the X-axis direction, it irradiates the recording medium 10 by irradiating the recording medium 10 with ultraviolet rays from the irradiation device 80 located on the rear side with respect to the scanning direction. The ultraviolet curable ink S can be irradiated 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.

  The ultraviolet curable ink S that is cured by ultraviolet rays irradiated from such an ultraviolet light source is prepared by adding an auxiliary agent such as an antifoaming agent or a polymerization inhibitor to a mixture of a vehicle, a photopolymerization initiator and a pigment. Can be mentioned. The vehicle is prepared by adjusting the viscosity of an oligomer, monomer or the like having photopolymerization curability with a reactive diluent. Therefore, the solvent is not volatilized for the purpose of curing the ink.

  As the vehicle, monofunctional or polyfunctional polymerizable compounds can be used. More specifically, oligomers (prepolymers) such as polyester acrylate, epoxy acrylate, and urethane acrylate can be exemplified, and these materials can also be used as a reactive diluent for adjusting the viscosity as an ink.

  As the photopolymerization initiator, benzophenone series, benzoin series, acetophenone series, and thioxanthone series are widely used. More specifically, 4-benzoyl-N, N, N-trimethyl benzene methanenannium chloride, 2-hydroxy 3- (4-benzoyl-phenoxy) -N, N, N-trimethyl 1-propylene, -N, N-dimethyl N- [2- (1-oxo-2-propenyloxy) ethyl] A quaternary ammonium salt type water-soluble organic substance such as benzene methanol bromide can be used. This type of photopolymerization initiator has different ultraviolet absorption characteristics, reaction initiation efficiency, yellowing, and the like depending on its composition, so that it is properly used depending on the color of the ink.

  As the polymerization inhibitor, any compound that has radical scavenging ability and inhibits radical polymerization can be used. However, in consideration of jetting suitability in the ink jet recording apparatus, at least one compound selected from hydroquinones, catechols, hindered amines, phenols, phenothiazines, and condensed aromatic ring quinones is preferable.

  Examples of hydroquinones include hydroquinone, hydroquinone monomethyl ether, 1-o-2,3,5-trimethylhydroquinone, 2-tert-butylhydroquinone and the like. Examples of catechols include catechol, 4-methylcatechol, 4-tert-butylcatechol and the like. Examples of hindered amines include compounds having a tetramethylpiperidinyl group.

  Examples of phenols include phenol, butylhydroxytoluene, butylhydroxyanisole, pyrogallol, gallic acid, gallic acid alkyl ester, and the like. Examples of phenothiazines include phenothiazine. Examples of the condensed aromatic ring quinones include naphthoquinone and the like.

  Furthermore, the polymerization inhibitor may be carbon black or inorganic / organic fine particles having a polymerization-inhibiting functional group introduced on the surface. Examples of the polymerization-preventing functional group include a hydroxyphenyl group, a dihydroxyphenyl group, a tetramethylpiperidinyl group, and a condensed aromatic ring.

  Examples of the ultraviolet curable ink S include color inks containing color materials (color components) such as pigments and dyes, and clear inks for undercoat and overcoat. In addition, a white ink and a black ink that are used for overcoating, although containing a color material, can also be used.

Next, the inspection unit 6 will be described with reference to FIG. FIG. 5 is a schematic view including the inspection unit 6, and is a side view seen from the + Y direction of FIG. 1.
The inspecting unit 6 inspects the ink ejection state of the nozzles 24, and specifically, detects mainly missing dots that occur when ink is not ejected from the nozzles 24.
As shown in FIG. 5, the inspection unit 6 includes an inspection ejection unit 61 and an inspection scanner 62 (imaging unit).

The inspection ejection unit 61 is for ejecting ink from the nozzles 24 of the ejection head 20 for inspection, and is disposed on the −X direction side of the suction table 33a.
The inspection ejection unit 61 includes, for example, a flexible film 61a (inspection medium) that can be used as an ejected area where the entire surface exposed toward the ejection head 20 can eject ultraviolet curable ink, and an ink A winding device that winds up the region of the ejected flexible film 61a and a delivery device that sends out the region of the flexible film 61a that is not ejected of ink are provided.
In the flexible film 61 a, the width of the exposed area (area where ink can be ejected) is set to about several times the width of the ejecting head 20, and the length of the exposed area is set to be approximately the same as that of the head unit 21.
In other words, the inspection ejection unit 61 can linearly arrange the ink ejected from each of the ejection heads 20 arranged shifted in the Y direction for each nozzle row 24A, and further includes the inspection ejection unit 61. By displacing in the X direction, the operation of ejecting ink from all the nozzles 24 can be repeated a plurality of times.
As the flexible film 61a, for example, a flexible film 61a made of polyethylene terephthalate (PET), polyethylene (PE), polycarbonate (PC), polypropylene (PP), or the like can be used.

Further, as shown in FIG. 5, the inspection ejection unit 61 is movable in the horizontal direction by a slide device 63 that is movable in the X direction.
In the present embodiment, the slide device 63 is configured to be able to move the inspection ejection unit 61 from a position below the ejection head 20 to a position below the inspection scanner 62.

The inspection scanner 62 is further spaced apart from the suction table 33a in the −X direction than the inspection ejection unit 61, and is fixedly disposed in an external region of the movable range of the ejection head 20 (head unit 21). Yes.
Then, the inspection scanner 62 images the ink ejected to the inspection ejecting unit 61 in the external region of the movable range of the ejection head 20.

As described above, in the liquid droplet ejecting apparatus 1 according to the present embodiment, the inspection ejection unit 61 can be moved horizontally, and the inspection scanner 62 is fixed.
Then, ink is ejected from the ejection head 20 to the inspection ejection unit 61 disposed below the ejection head 20, and then the ejected ink is imaged by moving the ejection head 20 to the inspection scanner 62. .

  Returning to FIG. 1, the control unit 60 controls the entire operation of the liquid droplet ejecting apparatus 1 of the present embodiment. For example, the control unit 60 controls the X-axis scanning mechanism 11 to perform main scanning in the X-axis direction, and controls the Y-axis scanning mechanism 42 to perform sub-scanning in the Y-axis direction. ing. Further, in addition to the scanning control by the control of the X-axis scanning mechanism 11 and the Y-axis scanning mechanism 42, the ejection control from the nozzles 24 (nozzle row 70) at the time of each scanning is performed. That is, it also has a function as an injection control unit that controls the injection corresponding to each scan.

  In the droplet ejecting apparatus 1 of the present embodiment, the control unit 60 imparts liquid repellency to the flexible film 61 a of the inspection unit 6 (hereinafter referred to as “liquid repellency imparting step”), and each nozzle 24. The step of inspecting the ink ejection state (hereinafter referred to as the inspection step) and the step of drawing on the recording medium 10 (hereinafter referred to as the drawing step) are performed.

The liquid repellency imparting step is performed before the inspection step, and the ultraviolet curable ink is ejected to the ejected region where the ultraviolet curable ink is ejected in the inspection step. This is a step of imparting liquid repellency to the ejected region by curing the ink.
That is, in the liquid droplet ejecting apparatus 1 of the present embodiment, the control unit 60 performs ultraviolet curing on the ejected area of the flexible film 61a before ejecting ultraviolet curing ink for inspecting the ink ejection state of the nozzles 24. Control is performed to impart liquid repellency to the ejected region by ejecting ink and curing the ejected ultraviolet curable ink.

In the inspection step, ultraviolet curable ink is ejected onto the ejected region to which liquid repellency is imparted.
That is, in the droplet ejecting apparatus 1 of the present embodiment, the ejected area of the flexible film 61a of the inspection unit 6 has liquid repellency, and ultraviolet curable ink is applied to the ejected area having the liquid repellency. Be injected.

  In the liquid droplet ejecting apparatus 1 of the present embodiment, the control unit 60 includes a nozzle 24 that ejects cyan ultraviolet curable ink, a nozzle 24 that ejects magenta ultraviolet curable ink, The ultraviolet curable ink is ejected from the nozzle 24 that ejects the yellow ultraviolet curable ink and the nozzle 24 that ejects the black ultraviolet curable ink to the ejected region of the flexible film 61a.

  In order to eject the ultraviolet curable ink onto the recording medium 10 and print a desired image by performing the drawing process with the droplet ejecting apparatus 1 having such a configuration, first, the control unit 60 performs X-axis scanning. The X-axis drive motor in the mechanism 11 and the Y-axis drive motor in the Y-axis scanning mechanism 42 are driven to sequentially change the relative positions of the ejection head 20 and the recording medium 10 on the suction table 33a. In parallel with such scanning control, a drive waveform (drive voltage) is applied to the piezoelectric element 59 of the ejection head 20 to drive it, and ultraviolet curable ink is ejected from each nozzle array 70 of the ejection head 20. The ink is sprayed and landed on the surface, and further irradiated with ultraviolet rays to cure the ultraviolet curable ink.

  When the liquid repellency imparting step is performed, cyan ultraviolet curable ink, magenta ultraviolet curable ink, and yellow ultraviolet curable ink are applied to the ejected area (exposed surface) of the flexible film 61a. As shown in FIG. 6A, a liquid repellent layer 100 is formed on the ejected region R by jetting black ultraviolet curable ink and further irradiating with ultraviolet rays. Liquid repellency is imparted to the region R.

  When performing the inspection process, as shown in FIG. 6B, the ultraviolet curable ink S is sprayed and arranged on the surface of the liquid repellent layer 100. Then, the control unit 60 moves the inspection ejection unit 61 by the slide device 63 to cause the inspection scanner 62 to image the ink landed on the inspection ejection unit 61, and based on this imaging data (by image processing) ) Determine the ink ejection state.

In such a droplet ejecting apparatus 1 (droplet ejecting method) of the present embodiment, since the ejected region R of the inspection unit 6 has liquid repellency, the ultraviolet rays that are ejected to the inspection unit 6 The curable ink approaches a spherical shape, and the height of the ultraviolet curable ink increases. Even a clear ink is not completely transparent, and therefore the light becomes difficult to transmit as the height of the ultraviolet curable ink increases. That is, as the height of the ultraviolet curable ink increases, the difference in density between the location where the ultraviolet curable ink exists and the surrounding area increases. Accordingly, the ejection region R of the inspection unit 6 has liquid repellency, and the height of the ultraviolet curable ink ejected onto the ejection region R increases, so that the detection of the ultraviolet curable ink can be easily and reliably performed. Can be done.
Therefore, according to the liquid droplet ejecting apparatus 1 (liquid droplet ejecting method) of the present embodiment, it is possible to reliably detect the ultraviolet curable ink in the inspection unit 6.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, before the inspection step (ink ejection for inspecting the ink ejection state of the nozzles 24), the ultraviolet curable ink is ejected to the ejection region R, The ejected ultraviolet curable ink is cured to impart liquid repellency to the ejected region R.
The ultraviolet curable ink exhibits liquid repellency with respect to the ink before being cured by being cured by being irradiated with ultraviolet rays.
For this reason, according to the droplet ejecting apparatus 1 of the present embodiment, even if the ejected region R does not have liquid repellency with respect to the ultraviolet curable type in advance, the liquid repellency with respect to the ejected region R Can be granted.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, in the liquid repellency imparting step, the nozzle 24 for ejecting cyan ultraviolet curable ink, the nozzle 24 for ejecting magenta ultraviolet curable ink, and the yellow ultraviolet light. The ultraviolet curable ink is ejected from the nozzle 24 that ejects the curable ink and the nozzle 24 that ejects the black ultraviolet curable ink to the ejection area of the flexible film 61a.
For this reason, since the ultraviolet curable ink is ejected from the many nozzles 24 to the ejection region R at a time, it becomes possible to impart liquid repellency to the ejection region R in a short time.

In the liquid droplet ejecting apparatus 1 of the present embodiment, clear ink may be ejected to the ejection region R in the liquid repellency imparting step.
When the ultraviolet curable ink is cured, it exhibits strong liquid repellency with respect to the same kind of ink before being cured. In a liquid droplet ejecting apparatus using clear ink, the most difficult to detect by image processing is clear ink having a large light transmittance. However, by using clear ink in the liquid repellency imparting step, the ejected region R is The clear ink has a large liquid repellency, and the clear ink can be detected more reliably.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, the moving speed of the ejecting head 20 is set in the liquid repellency imparting process, and the moving speed of the ejecting head 20 in the drawing process (when ejecting ink onto the ejected object). It is preferable to make it slower.
As a result, the moving speed of the ejection head 20 in the liquid repellency imparting process is slowed down, so that the ultraviolet curable ink ejected to impart liquid repellency to the ejected region R is irradiated with ultraviolet rays. As a result, the UV curable ink can be spread over a wide range.
For this reason, it is possible to arrange the ultraviolet curable ink over the entire area R to be ejected with a small amount of ink.

Moreover, in the droplet ejecting apparatus 1 of the present embodiment, it is preferable to impart liquid repellency to the entire exposed surface of the flexible film 61a of the inspection unit 6 before the inspection process.
The entire surface of the exposed flexible film 61a is wide enough to perform several inspection steps. This provides liquid repellency to the entire exposed flexible film 61a.
For this reason, it is not necessary to impart liquid repellency to the ejection region R every inspection step, and the ink ejection state can be inspected in a short time.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, the liquid repellency imparting step and the inspection step are performed in parallel with the drawing step. That is, when the ejection head 20 is disposed to face the recording medium 10, a drawing process is performed, and when the ejection head 20 is opposed to the inspection unit 6, a liquid repellency imparting process or an inspection process is performed.
Here, for example, in the liquid repellency imparting step, the ultraviolet curable ink is ejected onto the ejection region R when the ejection head 20 is reciprocated for the first time, and when the ejection head 20 is reciprocated for the second and subsequent times. It is conceivable to impart liquid repellency to the ejected region R by irradiating the ejected region R with ultraviolet rays.
According to this, since the ultraviolet curable ink is irradiated with ultraviolet rays during the second and subsequent reciprocating movements of the ejection head 20, liquid repellency is imparted until the ejection head 20 reciprocates at least once. Therefore, the ultraviolet curable ink ejected is not irradiated with ultraviolet rays, and the time for the ultraviolet curable ink to spread out can be secured.
Therefore, it is possible to dispose the ultraviolet curable ink over the entire area R to be ejected with a small amount of ink.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, it is preferable that the ejection resolution (ejection pitch) in the liquid repellency imparting step is coarser than the ejection resolution in the inspection step and the drawing step.
This also reduces the amount of ink required to impart liquid repellency.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, it is preferable that the landing diameter of the ultraviolet curable ink in the liquid repellency imparting process is larger than the landing diameter of the drawing process and the inspection process. According to this, since the landing diameter of the ultraviolet curable ink in the liquid repellency imparting step is increased, it is possible to reduce the number of times the ultraviolet curable ink is ejected when the liquid repellency is imparted.
For this reason, it becomes possible to complete the ejection of the ultraviolet curable ink for imparting liquid repellency in a shorter time.

Moreover, in the droplet ejecting apparatus 1 of the present embodiment, it is preferable that the ultraviolet curable ink is ejected a plurality of times to the same position of the inspection unit 6 (flexible film 61a) in the inspection process.
Accordingly, since the ultraviolet curable ink ejected later overlaps the ultraviolet curable ink ejected earlier, the height of the ultraviolet curable ink in the flexible film 61a can be increased, and the ultraviolet curable ink of the ultraviolet curable ink can be increased. Detection can be performed more easily and reliably. As a method of ejecting the ultraviolet curable ink a plurality of times at the same position, a method may be used in which ultraviolet curable ink is ejected to the same position from a plurality of different nozzles and then cured by irradiating ultraviolet rays all at once. Each time the ejection head 20 is moved once, a method of ejecting ink from one nozzle to the same place and irradiating ultraviolet rays to cure the ink may be used a plurality of times.

Further, in the liquid droplet ejecting apparatus 1 of the present embodiment, the ultraviolet curable ink may be ejected from the single nozzle 24 to different positions of the inspection unit 6 (flexible film 61a) in the inspection process.
In such a case, the inspection of the ink ejection state with respect to the single nozzle 24 can be determined from the ultraviolet curable ink ejected to a plurality of locations on the flexible film 61a. For this reason, it is possible to more reliably determine the ink ejection state.

The ultraviolet curable ink ejected from the single nozzle 24 may be linearly connected in the ejected region R.
Accordingly, it is possible to easily detect the ultraviolet curable ink by image processing as compared with the case where the ultraviolet curable ink ejected from the nozzle 24 is not connected to another ultraviolet curable ink.

Furthermore, in the liquid droplet ejecting apparatus 1 of the present embodiment, it is preferable that the width of the ejected region R is set to be not less than twice the landing diameter of the ultraviolet curable ink ejected in the inspection process.
Thus, a part of the ultraviolet curable ink ejected in the inspection process is prevented from exceeding the ejected region R, and the ultraviolet curable ink for inspecting the ink ejection state is surely ejected. It becomes possible to arrange in.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the above embodiment, the liquid droplet ejecting apparatus of the present invention is applied to a printing apparatus that performs printing on a continuous long recording medium. However, the present invention is not limited thereto, The object to be ejected is not long but can be a rectangular substrate. Moreover, as such a board | substrate, a glass substrate can also be made into object besides resin mentioned above.

  In the above embodiment, the irradiation device 80 is applied to a serial type printing device that is fixed to the sub-carriage 28 or the unit plate 23 and scans the head unit 21 in the X-axis direction by the X-axis scanning mechanism 11. The invention is not limited to this, and a head carriage in which the length of the head carriage 22 is equal to or longer than the length in the width direction of the printing area of the recording medium 10, a so-called line head, may be employed. Further, an irradiation device having a length equal to or greater than the length in the width direction of the printing area of the recording medium 10, a so-called line irradiation device may be employed. Further, an apparatus configuration is adopted in which the length of the head carriage 22 is equal to or less than the length in the width direction of the print area of the recording medium 10 and the head carriage 22 is fixed and the recording medium 10 is scanned in the X-axis direction. Also good.

  In the above embodiment, the case where the present invention is applied to a droplet ejecting apparatus mainly for industrial use has been described. However, the present invention can also be applied to a printer for consumer use.

Moreover, in the said embodiment, the structure which provides liquid repellency by injecting | curing an ultraviolet curable ink to the to-be-ejected area | region R, and hardening was demonstrated.
However, the present invention is not limited to this, and a configuration in which the jetted region R has liquid repellency may be employed by using a flexible film or the like that has been subjected to liquid repellency in advance by corona treatment or the like. .
In such a case, it is possible to use ink other than ultraviolet curable ink.

  DESCRIPTION OF SYMBOLS 1 ... Droplet injection apparatus, 10 ... Recording medium (jetting object), 6 ... Inspection part, 61 ... Inspection injection part, 61a ... Flexible film (inspection medium), 62 ... Inspection scanner, 20... Ejection head, 21... Head unit, 24... Nozzle, 60... Control unit, S .. UV curable ink (ink), R.

Claims (3)

A droplet ejecting apparatus comprising: a head that ejects ultraviolet curable ink; an ultraviolet irradiation unit that irradiates ultraviolet rays; and an inspection unit that inspects an ink ejection state of the head,
The head has a plurality of nozzles,
A first nozzle that ejects ink of a first color as the ink;
A second nozzle that ejects a second color ink as the ink;
Have
The head ejects the ink of the first color to form an ink layer;
The ultraviolet irradiation part irradiates the ink layer with ultraviolet rays to form a liquid repellent layer,
The head ejects the ink of the second color to be inspected toward the liquid repellent layer,
The droplet ejecting apparatus, wherein the inspection unit inspects the second color ink landed on the liquid repellent layer. Wherein either the one of the first color ink and the second color ink, a liquid droplet jetting apparatus according to claim 1, characterized in that the clear ink. A droplet ejection method for inspecting an ink ejection state of a droplet ejection device,
UV-curable first color ink is ejected to form an ink layer;
Irradiating the ink layer with ultraviolet rays to form a liquid repellent layer,
Injecting the ultraviolet curable second color ink to be inspected toward the liquid repellent layer,
A method for ejecting liquid droplets, wherein the ink of the second color landed on the liquid repellent layer is inspected.

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