JP2012045877A - Inkjet drawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet drawing device capable of forming a high-quality image.SOLUTION: The inkjet drawing device includes a head carriage, a head moving mechanism for moving the head carriage to a main scanning direction, an active light irradiation part for emitting active light, an irradiation part moving mechanism for moving the active light irradiation part to the main scanning direction, and a control part. The head carriage has an inkjet head for discharging an active light curable ink as liquid droplets on a medium to be recorded like an image, a first mirror, and a second mirror. The control part controls the head moving mechanism and the irradiation part moving mechanism so that light from the active light irradiation part is irradiated to a mirror positioned behind in the moving direction of the head carriage, which is the first mirror or the second mirror, and so that the light reflected by the mirror is irradiated to the active light curable ink on the medium to be recorded.

Description

  The present invention relates to a technique for ejecting liquid from an ejection nozzle provided in an ejection head.

2. Related Art There is known an ink jet drawing apparatus that ejects a liquid onto a medium from an ejection nozzle provided in an ejection head while reciprocating the ejection head. By using this ink jet drawing apparatus, a liquid that is cured by irradiation with ultraviolet rays (ultraviolet light) is ejected from the ejection nozzle onto the medium, and the liquid is cured by irradiating the ejected liquid with ultraviolet rays. A technology for fixing a liquid on the surface has been developed.
In such a technique, the liquid can be instantly cured and fixed on the medium, so that the liquid can be well fixed even on a material that does not absorb liquid, such as plastic (polyethylene terephthalate, polycarbonate). Is possible. Such a conventional ink jet drawing apparatus includes a light source that emits ultraviolet light mounted on a carriage (see, for example, Patent Document 1).

JP 2009-119862 A

In the ink jet drawing apparatus described in Patent Document 1, the path of ultraviolet light from one light source can be selectively switched to one of a plurality of paths. For this reason, it is possible to easily reduce the number of light sources. As a result, the ink jet drawing apparatus can be easily miniaturized.
However, in the ink jet drawing apparatus described in Patent Document 1, since the light source is mounted on the carriage, the load on the carriage tends to increase. When the load applied to the carriage increases, it becomes difficult to improve the accuracy of the carriage position control, and thus the recording accuracy.
That is, the conventional ink jet drawing apparatus has a problem that it is difficult to improve drawing accuracy.

  Application Example 1 An ink jet drawing apparatus according to this application example includes a platen that supports a sheet-like recording medium, an ink jet head that ejects actinic ray curable ink as droplets imagewise on the recording medium, and , A head carriage having a first mirror and a second mirror, a head moving mechanism for moving the head carriage in the main scanning direction, an actinic ray irradiating unit for emitting actinic rays, and the actinic ray irradiating unit An irradiating part moving mechanism for moving the ink jet head in the main scanning direction, and a control unit, wherein the ink jet head is positioned between the first mirror and the second mirror in the main scanning direction of the head carriage. Of the first mirror or the second mirror, the active mirror is positioned on a mirror located behind the moving direction of the head carriage. The control unit includes the head moving mechanism and the head moving mechanism so that the active light from the light irradiation unit is irradiated and the active light reflected by the mirror is applied to the active light curable ink on the recording medium. The irradiation unit moving mechanism is controlled.

In the above configuration, the head carriage is provided with the first mirror and the second mirror together with the ink jet head, and the head carriage is moved by the head moving mechanism. Then, the actinic ray irradiation unit moves by an irradiation unit moving mechanism different from the head moving mechanism. Then, by the control of the head moving mechanism of the control unit and the irradiation unit moving mechanism, the light from the actinic ray irradiation unit is irradiated to the mirror located behind the moving direction of the head carriage among the first mirror or the second mirror. Then, the light reflected by the mirror is applied to the actinic ray curable ink on the recording medium.
According to the above configuration, the head carriage is not provided with the actinic ray irradiating unit, so that the head carriage can be reduced in weight. Therefore, it is possible to improve the accuracy of the carriage position control, and thus the recording accuracy. In addition, the time from when an image is drawn on the recording medium by the inkjet head to when the image portion on the recording medium is irradiated with ultraviolet rays by the light source unit and cured can be shortened, and the recording It is possible to prevent image disturbance caused by the image formed on the medium blurring on the recording medium or the image shifting. Thereby, a high-quality image can be formed.

  Application Example 2 In the ink jet drawing apparatus according to the application example described above, the first mirror or the second mirror may be disposed at a position higher than a nozzle surface of the ink jet head.

  According to such a structure, it can suppress that the light from an actinic ray irradiation part enters between a recording medium and an inkjet head. As a result, it is possible to form a high-quality image in which image disturbance due to ejection failure is prevented on the recording medium. In addition, ink droplets can be ejected satisfactorily for a long time without performing maintenance such as cleaning / cleaning on the inkjet head.

  Application Example 3 In the ink jet drawing apparatus according to the application example, the actinic ray irradiation unit may be arranged at a position higher than a nozzle surface of the ink jet head.

  According to such a structure, it can suppress that the light from an actinic ray irradiation part enters between a recording medium and an inkjet head. As a result, it is possible to form a high-quality image on the recording medium in which image disturbance due to ejection failure is prevented. In addition, ink droplets can be ejected satisfactorily for a long time without performing maintenance such as cleaning / cleaning on the inkjet head.

1 is a schematic top view showing a schematic configuration of a plate making apparatus as an embodiment to which an ink jet drawing apparatus according to the present invention is applied. It is a typical side view of the plate making apparatus shown in FIG. It is sectional drawing which shows schematic structure of the inkjet head used for the plate-making apparatus shown in FIG. It is typical sectional drawing which looked at the scanning UV irradiation part of the plate-making apparatus shown in FIG. 1 from the back surface. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic top view showing a positional relationship between an ink jet head carriage and a light source unit of the plate making apparatus shown in FIG. 1. FIG. 2 is a schematic sectional view showing the positional relationship between the ink jet head carriage and the light source unit of the plate making apparatus shown in FIG. 1.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an ink jet drawing apparatus according to the invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic top view showing a schematic configuration of a plate making apparatus as an embodiment to which an ink jet drawing apparatus according to the present invention is applied, and FIG. 2 is a schematic side view of the plate making apparatus shown in FIG. It is. 3 is a cross-sectional view showing a schematic configuration of an example of the ink jet head shown in FIG. 1, and FIG. 4 is a schematic cross-sectional view of the scanning UV irradiation unit of the plate making apparatus shown in FIG. It is.

  In the following, a lithographic printing original plate as a recording medium, an ultraviolet ray curable ink (hereinafter referred to as UV ink) Q as an actinic ray curable ink, and a dot shape or a substantially dot shape for irradiating ultraviolet rays (hereinafter referred to as UV light). A plate making apparatus for producing a printing plate using an ultraviolet lamp (hereinafter referred to as a UV lamp) as a light source will be described as a representative example. However, the present invention is not limited to this, and may be, for example, a printed circuit board manufacturing apparatus for manufacturing a printed circuit board, an ink jet printer for drawing an image on paper, a resin sheet, or the like.

A plate making apparatus 10 shown in FIGS. 1 and 2 is an ink jet drawing apparatus that forms a printing ink receptive (ink affinity) image portion on a recording surface of a sheet-like printing original plate P as a recording medium by an ink jet recording method. Applicable.
The plate making apparatus 10 includes a platen 12 that supports the printing original plate P, a head including an inkjet head (recording head) 62 that discharges the UV ink Q imagewise onto the printing original plate P, a first mirror 47A, and a second mirror 47B. The carriage 14, the scanning UV irradiation unit 16 that scans and irradiates the UV ink Q ejected on the printing original plate P with UV light in the main scanning direction (direction indicated by arrow Y in FIG. 1), and the head carriage 14 are mainly used. A head moving mechanism 18 that moves in the Y direction, which is the scanning direction, and the printing original plate P supported by the platen 12 in the sub-scanning direction (indicated by an arrow X in FIGS. 1 and 2) substantially orthogonal to the main scanning direction (Y direction). And a control unit 22 that controls operations of the head carriage 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 20.

  The platen 12 has a flat plate shape, and supports the printing original plate P supplied from an automatic plate feeding apparatus (not shown) on the surface thereof. Here, it is preferable to provide an air suction hole on the surface of the platen 12 to attract the printing original plate P during drawing by the head carriage 14, that is, during drawing by the inkjet head 62 of the head carriage 14. Thereby, the flatness of the printing original plate P can be maintained appropriately. Further, when the printing original plate P is conveyed in the sub-scanning direction (X direction) by the conveying mechanism 20, it is preferable that the surface of the platen 12 has a small friction coefficient with the back surface of the printing original plate P. The platen 12 is attached to a plate making apparatus housing (not shown).

  The transport mechanism 20 transports the printing original plate P to the head carriage 14 in the sub-scanning (X) direction. The transport mechanism 20 includes a feed roller 30 that is a drive roller connected to a drive source (not shown) and a holding roller 32 that is a driven roller, and the printing original plate P is placed between the feed roller 30 and the holding roller 32. It is nipped and conveyed in the sub-scanning (X) direction. The feed roller 30 and the pressing roller 32 are arranged on the transport path of the printing original plate P so as to sandwich the front and back of the printing original plate P from above and below. The printing original plate P supplied from the automatic plate feeder is sandwiched between the feed roller 30 and the suppression roller 32 with a predetermined nip pressure. By rotating the feed roller 30 in a predetermined direction (counterclockwise in FIG. 2) by a driving source (not shown), the printing original plate P is conveyed in the sub-scanning (X) direction.

Further, when the printing original plate P is attracted to the surface of the platen 12 during drawing by the head carriage 14, the feed roller 30 and the suppression roller 32 stop rotating, and the feed roller 30 during non-drawing by the head carriage 14. It is preferable that the printing original plate P 30 is rotated by a drive source (not shown) and is sandwiched between the pressing roller 32 and conveyed in the sub-scanning (X) direction. That is, the transport mechanism 20 preferably transports the printing original plate P intermittently in the sub-scanning direction. Both the feed roller 30 and the pressure roller 32 are rotatably supported by a plate making apparatus casing (not shown).
The transport mechanism used in the present invention (described in the above embodiment as the transport mechanism 20) may be of any type as long as it can transport the printing original plate in the sub-scanning direction. The sub-scanning transport mechanism can be applied.

  The head carriage 14 includes an inkjet head 62, a first mirror 47A, and a second mirror 47B. In the present embodiment, the head carriage 14 is disposed such that the platen 12 and the inkjet head 62 are opposed to each other, and the head carriage 14 is disposed above the recording surface of the printing original plate P supported on the surface of the platen 12. The head carriage 14 is supported by a later-described head moving mechanism 18 so as to be capable of reciprocating (scanning) in the main scanning direction (Y direction) parallel to the surface of the platen 12.

The ink jet head 62 of the head carriage 14 ejects the UV ink Q as ink droplets on the recording surface of the printing original plate P placed on the platen 12 in an image-like manner. That is, the UV ink Q is ejected according to the ejection signal based on the image data of the image to be recorded. An image is recorded on the printing original plate P by the discharged UV ink Q to form an ink-philic image portion.
Here, the ejection signal is a data signal for ejecting droplets so as to selectively apply ink to a portion to be an image portion based on image data of an image to be recorded. The recording surface of the printing original plate P exhibits ink repellency (hydrophilicity), and only the image portion formed by the ejection of the UV ink Q exhibits ink affinity (hydrophobicity).

FIG. 3 is a cross-sectional view showing a schematic configuration of the inkjet head 62 of the head carriage 14 used in the plate making apparatus 10 shown in FIG.
The inkjet head 62 includes a case 102, a nozzle plate 104, a guard plate 106, and a piezoelectric element 108.

In the inkjet head 62 shown in FIG. 3, a flow path for the UV ink Q is formed by the discharge port 102 c formed in the case 102 and the nozzle 104 a formed in the nozzle plate 104. A plurality of nozzles 104a are formed in communication with the nozzle plate 104 at a position corresponding to the side surface of the ink flow path, and the ink Q in the case 102 is ejected as ink droplets from the nozzle 104a on the side surface of the ink flow path. This is a side shooter type inkjet head.
Here, FIG. 3 shows only some of the nozzles 104a of the inkjet head 62. However, the inkjet head 62 has a plurality of nozzles 104a (not shown) that discharge ink droplets. Are arranged in a line in the sub-scanning direction (X direction) at the time of drawing.

Hereinafter, each member of the inkjet head 62 will be described in detail.
The case 102 has a hollow box shape, and a plurality of ink outlets 102a and a plurality of ink inlets 102b are formed on one surface. On the surface opposite to the surface on which the ink outlet 102a and the ink inlet 102b are formed, an ejection port 102c is formed at a position between the ink outlet 102a and the ink inlet 102b. In addition, piezoelectric elements 108 (for example, PZT drive) are arranged in the ink flow path which is also a pressure chamber inside the case 102 so as to correspond to the respective ejection ports 102c.

  The nozzle plate 104 is disposed on the surface of the case 102 on the discharge port 102c side, and the nozzle 104a is formed at a position corresponding to the discharge port 102c. The nozzle 104a communicates with the ejection port 102c, and the ink Q fed to the ejection port 102c is ejected as ink droplets.

  The guard plate 106 is disposed on the outer surface of the nozzle plate 104 and is disposed so as to protrude near the nozzle 104 a of the nozzle plate 104. The guard plate 106 protects the nozzle 104a so that other members do not collide with the nozzle 104a.

  The ink jet head 62 drives the piezoelectric element 108 to eject the ink Q fed from the ink inlet 102b to the ejection outlet 102c from the nozzle 104a. Then, the ink Q that is not ejected is delivered from the ink outlet 102a. At this time, the ink Q is ejected as ink droplets without being precipitated by the circulation and stirring of the ink Q in the pressure chamber of the case 102. For the inkjet head 62, a method may be used in which the temperature of the entire head is controlled and heated with a heater or the like to reduce the viscosity of the ink Q to facilitate ejection.

  The ink jet head is not limited to the side shooter type piezo method of the above-described embodiment, and various types of ink jets such as a continuous type and an on-demand type piezo method, a thermal method, a solid method, and an electrostatic suction method. A head (discharge head) can be used, and it is particularly preferable to use various types of on-demand ink jet heads. Further, the nozzles are not limited to a single row arrangement, and may be arranged in a plurality of rows or in a staggered pattern.

  The first mirror 47A and the second mirror 47B of the head carriage 14 reflect UV light from a light source unit (ultraviolet irradiation unit) 38, which will be described later, on the recording surface of the printing original plate P as shown in FIG. The discharged UV ink Q is irradiated.

  When the recording surface of the printing original plate P is viewed from above in the vertical direction, the inkjet head 62 is disposed so as to be positioned between the first mirror 47A and the second mirror 47B in the main scanning direction (Y direction). Is done. The irradiation range of the first mirror 47A and the second mirror 47B is configured to be an irradiation range longer than the length of the row of the plurality of nozzles 104a arranged in the sub-scanning direction (X direction).

  Typically, the length of the first mirror 47A and the second mirror 47B in the sub-scanning direction (X direction) is longer than the length of the row of the plurality of nozzles 104a. Then, since the UV light from the light source unit 38 is reflected by the first mirror 47A or the second mirror 47B disposed on both sides of the inkjet head 62 in the main scanning direction (Y direction), the inkjet head 62 is mainly used. The UV ink Q ejected from the inkjet head 62 during the period of passing once over the printing original plate P in the scanning direction (Y direction) is irradiated with the UV light from the light source unit 38 within that period.

  The first mirror 47 </ b> A and the second mirror 47 </ b> B are preferably arranged at a position higher in the vertical direction than the inkjet head 62, particularly the nozzle plate 104. 2 and 11, the heights h1 and h2 from the lower ends of the first mirror 47A and the second mirror 47B to the recording surface of the printing original plate P are higher than the height h0 of the nozzle plate 104 in the vertical direction. It is high.

  According to such a configuration, it is possible to prevent UV light from the light source unit (ultraviolet irradiation unit) 38 from entering between the recording surface of the printing original plate P and the inkjet head 62. As a result, it is possible to form a high-quality image on the recording medium in which image disturbance due to ejection failure is prevented. Further, it is possible to discharge ink droplets stably for a long time without performing maintenance such as cleaning / cleaning on the inkjet head 62.

  As shown in FIGS. 1 and 2, the head moving mechanism 18 reciprocates (scans) the head carriage 14 in the main scanning direction. The head moving mechanism 18 includes a drive screw 34, a guide rail 35, a drive support portion 36a, and a support portion 36b. The drive screw 34 and the guide rail 35 are both extended so as to extend in the main scanning direction (Y direction in FIG. 1) so that the maximum size of the printing original plate P that can be drawn extends from one end to the other end in the main scanning direction. Has been.

The drive screw 34 is composed of a ball screw (not shown) having a male screw portion that is screwed with a female screw portion (not shown) formed on the head carriage 14, and rotates the head carriage 14 in the main scanning direction. Move.
The guide rail 35 is a guide that is inserted into a through-hole formed in the head carriage 14 and guides the posture of the inkjet head 62 that moves by the rotation of the drive screw 34 so as not to change.

  The drive support portion 36a is provided at one end portion of the drive screw 34 and the guide rail 35, and the support portion 36b is provided at the other end portion thereof, and supports the drive screw 34 in a state where the drive screw 34 can be rotated forward and backward. The guide rail 35 is supported so as not to move. The drive support portion 36 a includes a drive source (not shown) such as a motor that drives the drive screw 34.

The head carriage 14 is movably supported by a drive screw 34 and a guide rail 35, and is rotated in the forward and reverse directions by the drive support portion 36a, so that the head carriage 14 is guided by the guide rail 35 while being guided in the Y direction (main scanning). Direction).
The head moving mechanism 18 may be provided with a plurality of guide rails or other posture holding means in order to maintain the posture of the head carriage 14. The head carriage 14 is moved by the guide rail 35 while maintaining a predetermined posture in which the ink droplet ejection portion, that is, the ink droplet ejection surface of the inkjet head 62 faces the platen 12.

Here, the moving mechanism of the head carriage 14 is not limited to the head moving mechanism 18 described above, and various known moving mechanisms can be used.
For example, the drive screw is a rod-shaped member such as a guide rail, and guide wires are attached to both sides of the Y-direction end of the inkjet head, and the guide wire in the moving direction is wound and moved along the guide rail. Can also be used.
Moreover, you may move with a timing belt instead of a guide wire. In this case, a timing belt sprocket may be used instead of the wire reel.
Further, a rack and pinion mechanism may be used. Moreover, it is good also as a self-propelled type. Further, a linear motor may be used.

  FIG. 4 is a rear cross-sectional view schematically showing the scanning UV irradiation unit 16 of the plate making apparatus 10 shown in FIG. 1, and the downstream side is viewed from the upstream side in the feeding direction (sub-scanning (X) direction) of the printing original plate P. It is a figure.

Next, as shown in FIG. 4, the scanning UV irradiation unit 16 includes a light source unit (ultraviolet irradiation unit) 38 and a light source unit moving mechanism 46. The scanning UV irradiation unit 16 is disposed on the downstream side of the head carriage 14 in the feeding direction of the printing original P (sub-scanning (X) direction).
The scanning UV irradiation unit 16 scans the light source unit 38 in the main scanning (Y) direction and emits UV light toward either the first mirror 47A or the second mirror 47B provided on the head carriage 14. Irradiate. The UV light emitted from the light source unit 38 is reflected by either the first mirror 47A or the second mirror 47B provided on the head carriage 14, and is applied to the UV ink Q on the recording surface of the printing original plate P. The The UV ink Q is ejected from the inkjet head 62 in an image-like manner on the recording surface of the printing original plate P to form an image portion.

The UV ink Q on the recording surface of the printing original plate P is cured by the UV light irradiated and reflected from the light source unit 38.
Here, the scanning UV irradiation unit 16 has a light source unit on a mirror located on the rear side of the moving direction in the main scanning direction (Y direction) of the ink jet head 62 among the first mirror 47A or the second mirror 47B. It is controlled by the control unit 22 so that the UV light from 38 is irradiated. Therefore, the UV ink Q immediately after being ejected from the ink jet head 62 is irradiated with the UV light from the light source unit 38. In addition, since the light source unit 38 is provided in the scanning UV irradiation unit 16 that can move (scan) independently of the head carriage 14, compared with the case where the light source unit 38 is attached to the head carriage 14. The head carriage 14 can be reduced in weight.

As shown in FIGS. 2 and 4, the light source unit 38 includes a UV lamp 40 that emits UV light, and light that is parallel to the recording surface of the printing original plate P supported on the platen 12. And a reflector 42.
The light source unit 38 is housed in a housing 51 and configured as a lamp house. Here, the inner surface of the housing 51 is preferably a mirror surface.

The UV lamp 40 emits UV light for curing the UV ink Q. As the UV lamp 40, for example, various lamps (point light sources) such as ultra-high pressure mercury lamps and metal halide lamps, tube bulbs such as ultraviolet fluorescent tubes, and lamps made substantially dotted using these can be used. .
These light sources may emit light including visible light. If the photosensitive area of the actinic ray curable ink (in this embodiment, the UV ink) has sensitivity in the visible light range, the sensitivity can be further increased by irradiating light including visible light, The UV ink can be suitably cured.
In the present invention, a UVLED or a UVLED array may be used instead of the UV lamp 40 used in the present embodiment. Further, as the UV lamp 40, it is preferable to use an ultra high pressure mercury lamp (ultra high pressure mercury lamp) used in a video projector or a rear projection type television. By using an ultra-high pressure mercury lamp as the UV lamp 40, the light source unit 38 can be made inexpensive.

  The reflector 42 includes a UV lamp 40 and includes an injection port 42 a having a rectangular cross-sectional shape for emitting UV light emitted from the UV lamp 40. The inner surface of the reflector 42 is a mirror surface, and the UV light emitted from the UV lamp 40 is reflected without being absorbed by the inner surface. Thereby, the UV light emitted from the UV lamp 40 is directly or directly reflected by the reflector 42 and is emitted as UV light from the emission port 42a without being absorbed.

  As shown in FIG. 4, the light source unit moving mechanism 46 is positioned on both outer sides of the platen 12 or an area serving as a transport path for the maximum-size printing original plate P that can be drawn, that is, on both outer sides in the main scanning direction (Y direction). Two wire reels 48a and 48b, a wire 50 stretched between the two wire reels 48a and 48b, and a drive source (motor) 52 that rotationally drives the wire reel 48a. The light source unit 38 is fixedly attached to the wire 50 with the illumination window 53 of the housing 51 facing upstream in the feeding direction of the printing original plate P (sub-scanning (X) direction). In other words, the light source unit 38 is fixedly attached to the wire 50 with the illumination window 53 of the housing 51 facing the head carriage 14. Both ends of the wire 50 are wound around wire reels 48a and 48b, respectively.

  The wire reels 48a and 48b are pivotally supported by a frame (not shown), and the wire reel 48b is always urged with a predetermined tension in the direction of winding the wire 50. A conventionally well-known technique may be used as a method for biasing the wire reel 48b. For example, a mainspring spring, a coil spring, or a plate coil spring can be used as the biasing means. The urging force of the wire reel 48 b may be set so that the light source unit 38 can be held at a certain distance from the printing original plate P without loosening the wire 50.

  Here, the position of the light source unit 38, particularly the UV lamp 40 or the illumination window 53, is preferably arranged at a position higher than the inkjet head 62, particularly the nozzle plate 104. As shown in FIG. 2, the height h3 from the lower end of the illumination window 53 to the recording surface of the printing original plate P is higher than the height h0 of the nozzle plate 104 in the vertical direction.

According to such a configuration, it is possible to prevent UV light from the light source unit (ultraviolet irradiation unit) 38 from entering between the recording surface of the printing original plate P and the inkjet head 62. As a result, a high-quality image in which image disturbance due to defective ejection is prevented can be formed on the printing original plate P (recording medium).
In addition, ink droplets can be ejected satisfactorily for a long time without performing maintenance such as cleaning / cleaning on the inkjet head.

When the wire reel 48a is rotationally driven by the drive source 52 in the direction in which the wire 50 is unwound (counterclockwise in FIG. 4), the wire reel 48b is rotated by the biasing force and winds the wire 50. When the wire reel 48a stops, the wire reel 48b also stops when the wire 50 reaches a predetermined tension.
Conversely, when the wire reel 48a is rotationally driven in the direction in which the drive source 52 winds the wire 50 (clockwise in FIG. 4), the urging force of the wire reel 48b is lost and the wire 50 is unwound from the wire reel 48b. It is wound on a reel 48a.

  In this way, the scanning UV irradiation unit 16 moves the wire 50 in the main scanning direction (arrow Y in the figure) while maintaining a substantially constant tension on the wire 50 by the rotational driving of the wire reel 48a by the drive source 52. The light source unit 38 attached to the wire 50 is reciprocated in the main scanning direction substantially parallel to the recording surface of the printing original plate P.

  In the example shown in FIG. 4, only the state in which the light source unit 38 is attached to the wire 50 is shown in order to clearly show the configuration of the light source unit moving mechanism 46. In order to keep the posture of the unit 38 parallel to the platen 12, it is preferable to include one or more guide rails or other posture holding means for guiding the movement of the light source unit 38 in the main scanning direction.

  The light source unit 38 scans while irradiating the head carriage 14 with the UV light emitted from the UV lamp and reflected by the reflector 42 by moving in the main scanning direction. By controlling the amount of rotation of the wire reel 48a by the drive source 52 and controlling the movement of the light source unit 38 by the control unit 22, the left end of the full width area of the printing original plate P as the light source unit 38 reciprocates. UV irradiation is performed in order from the right end to the right end.

Here, the mechanical accuracy of the light source unit moving mechanism 46 may be lower than that of the head moving mechanism 18. This is because the UV light from the light source unit 38 may be configured to reach the first mirror 47A or the second mirror 47B. The lengths of the first mirror 47A and the second mirror 47B in the main scanning direction are preferably longer than the length of the illumination window 53 in the main scanning direction.
For example, if the length of the first mirror 47A and the second mirror 47B in the main scanning direction is three times that of the illumination window 53, the movement delay of the light source unit 38 relative to the head carriage 14 is within three times that of the illumination window 53. The light source unit moving mechanism 46 may be controlled so as to be within the range.

  The drive source 52 only needs to be capable of rotating the wire reel 48a in the forward direction and the reverse direction. For example, an electric motor can be used.

As described above, the control unit 22 controls the operations of the head carriage 14, the scanning UV irradiation unit 16, the head moving mechanism 18, and the transport mechanism 20.
Specifically, the control unit 22 discharges the UV ink Q according to the image data by the inkjet head of the head carriage 14 to form the image portion on the printing original plate P, and forms the image portion on the printing original plate P. Scanning UV irradiation by the scanning UV irradiation unit 16 for curing the UV ink Q, that is, the reciprocation of the light source unit 38 by the light source unit moving mechanism 46 (main scanning direction), the head carriage by the head moving mechanism 18 14 reciprocating movements (main scanning direction) and continuous conveyance (preferably intermittent conveyance) of the printing original plate P in the sub-scanning direction by the conveyance mechanism 20 are controlled. In addition, it is preferable that the control part 22 controls the whole plate-making apparatus 10 or all the components which are not shown in figure.

  Here, the control unit 22 uses the head moving mechanism 18 and the light source unit moving mechanism 46 to move the head carriage 14 and the light source unit 38 in the main scanning direction at the same cycle and the positional relationship between the head carriage 14 and the light source unit 38. Move so as to be within a predetermined range.

Next, the operation of the plate making apparatus 10 shown in FIGS. 1 and 2 will be described with reference to FIGS.
5 to 10 are schematic top views showing the positional relationship between the ink jet head 14 and the light source unit 38 of the plate making apparatus 10 shown in FIG. FIGS. 11A and 11B are schematic cross-sectional views showing the positional relationship between the inkjet head 14 and the light source unit 38.
In the description, left and right are used, but the left side indicates the direction from the center to the wire reel 48a side in the main scanning direction (Y direction), and the right side indicates the main scanning direction (Y direction). The direction from the center to the wire reel 48b side is indicated.

  In the plate making apparatus 10 shown in FIGS. 1 and 2, the printing original plate P is supplied to the platen 12 from an automatic plate feeding apparatus (not shown). The printing original plate P supplied to the platen 12 is intermittently conveyed at a predetermined speed by the conveyance mechanism 20 in the sub-scanning direction (X direction in FIG. 1).

  The printing original plate P is transported to a position facing the head carriage 14 by the transport mechanism 20. The head carriage 14 ejects UV ink Q from the inkjet head 62 onto the surface of the printing original plate P in accordance with the image signal while being moved in the main scanning direction by the head moving mechanism 18. As a result, an image portion is formed on the surface of the printing original plate P by the UV ink Q.

  As shown in FIG. 5, when the UV ink Q is ejected while scanning the head carriage 14 toward the right side in the main scanning direction (Y direction), the UV light from the light source unit 38 is applied to the second mirror 47B. The head carriage 14 and the light source unit 38 are moved in the main scanning direction by the head moving mechanism 18 and the light source unit moving mechanism 46 while maintaining the positional relationship toward the head.

  Here, as shown in FIG. 11B, the relative positional relationship between the head carriage 14 and the light source unit 38 is set so that the UV light from the light source unit 38 is directed to the second mirror 47B. Here, the UV light from the light source unit 38 emitted in parallel to the recording surface is irradiated to the second mirror 47B. The UV light applied to the second mirror 47B is reflected toward the recording surface of the printing original plate P by being reflected by the second mirror 47B. Since the UV ink Q discharged from the ink jet head 62 is disposed on the recording surface of the printing original plate P, the UV light from the light source unit 38 is irradiated to the UV ink Q, and the UV ink Q is cured. It will be.

  As shown in FIG. 6, when the head carriage 14, in particular, the inkjet head 62 passes through the position facing the printing original plate P and is positioned on the right side of the platen 12, the head carriage 14 stops. On the other hand, the light source unit 38 does not stop and moves to the right in the main scanning direction. Further, after the movement in the main scanning direction is finished, the printing original plate P supplied to the platen 12 is conveyed by a predetermined amount in the sub-scanning direction (X direction in FIG. 1) by the conveying mechanism 20.

  Then, as shown in FIG. 7, the main scanning direction is moved to the right until the UV light from the light source unit 38 moves from the state toward the second mirror 47 </ b> B toward the first mirror 47 </ b> A, and the light source unit 38. Stops.

Next, as shown in FIG. 8, when the UV ink Q is ejected while scanning the head carriage 14 toward the left side in the main scanning direction (Y direction), the UV light from the light source unit 38 is the first light. While maintaining the positional relationship toward the mirror 47A, the head carriage 14 and the light source unit 38 are moved to the left in the main scanning direction by the head moving mechanism 18 and the light source unit moving mechanism 46.
Here, as shown in FIG. 11A, the relative positional relationship between the head carriage 14 and the light source unit 38 is set so that the UV light from the light source unit 38 is directed to the first mirror 47A. . Here, the UV light from the light source unit 38 emitted in parallel to the recording surface is irradiated to the first mirror 47A. Then, the UV light irradiated on the first mirror 47A is guided toward the recording surface of the printing original plate P by being reflected by the first mirror 47A. Since the UV ink Q discharged from the ink jet head 62 is disposed on the recording surface of the printing original plate P, the UV light from the light source unit 38 is irradiated to the UV ink Q, and the UV ink Q is cured. It will be.

As shown in FIG. 9, when the head carriage 14, particularly the inkjet head 62, passes through the position facing the printing original plate P and is positioned on the left side of the platen 12, the head carriage 14 stops. On the other hand, the light source unit 38 does not stop and moves to the left in the main scanning direction. Further, after the movement in the main scanning direction is finished, the printing original plate P supplied to the platen 12 is conveyed by a predetermined amount in the sub-scanning direction (X direction in FIG. 1) by the conveying mechanism 20.
Then, as shown in FIG. 10, the UV light from the light source unit 38 moves until it moves from the state toward the first mirror 47A to the state toward the second mirror 47B, and the light source unit 38 stops. Next, if the image formation is not completed, returning to FIG. 5, drawing by the inkjet head 62 and UV light irradiation by the light source unit 38 are performed.

  Thus, the movement period of the light source unit 38 is slightly longer than the movement period of the head carriage 14. Further, the moving distance of the light source unit 38 is slightly longer than the moving distance of the head carriage 14. Note that, by using the difference in the movement period, the transport mechanism 20 may transport the printing original plate P in the sub-scanning direction or perform regular flushing of the inkjet head.

Then, the ink jet head 62 of the head carriage 14 is transported by the transport mechanism 20 in the sub-scanning direction and the head carriage 14 is reciprocated in the main scanning direction (Y direction in FIG. 1) by the head moving mechanism 18. The entire surface of the printing original plate P is scanned, and an image portion using UV ink Q is formed at a required position on the entire surface of the printing original plate P.
More specifically, as shown in FIG. 1, every time the inkjet head carriage 14 scans the entire area of the printing original P (recording medium) in the main scanning direction, the transport mechanism 20 moves the printing original P in the sub-scanning direction. By moving dx, the entire printing original plate P is scanned to form an image.

  In this way, the head carriage 14 is moved at a position where the head carriage 14 does not overlap each other in plan view. Therefore, adjustment of the relative positional relationship between the head carriage 14 and the light source unit 38 is performed without interfering with each other, so that control becomes easy. Further, since the light source unit 38, the first mirror 47A, and the second mirror 47B can be arranged close to the printing original plate P, the light source is arranged on the inkjet head 62 as in Patent Document 1. In comparison, the optical path from the light source unit 38 to the printing surface of the printing original plate P can be shortened. Therefore, the UV light from the light source unit 38 can be irradiated to the UV ink Q on the printing original plate P without loss.

  Further, of the first mirror 47A or the second mirror 47B, the UV light from the light source unit 38 is irradiated to the mirror on the rear side in the traveling direction of the head carriage 14 with respect to the inkjet head 62. Then, the printing original plate P (part thereof) that has passed through the position of the head carriage 14 that faces the inkjet head 62 is then moved from the first mirror 47A or the second mirror 47B to the inkjet carriage 62 with respect to the head carriage 14. Is conveyed to a position facing the rear mirror in the traveling direction. Therefore, the UV ink Q discharged from the inkjet head 62 is irradiated with the UV light from the light source unit 38 during the movement period in the main scanning direction in which the UV ink Q is discharged. Therefore, after the image is drawn on the printing original plate P by the ink jet head 62, the time until the image portion on the printing original plate P is irradiated with UV light by the light source unit and cured can be shortened. It is possible to prevent image disturbance caused by an image formed on the printing original plate P blurring on the printing original plate P or an image shift. Thereby, a high-quality image can be formed.

  As described above, the scanning UV irradiation unit 16 causes the light source unit 38 to reciprocate in the main scanning direction by the light source unit moving mechanism 46, and causes the UV light emitted from the UV lamp 40 to be emitted from the first mirror 47A or the second mirror. Is irradiated onto the UV ink Q of the image portion formed on the recording surface of the printing original plate P through the mirror 47B. That is, by performing serial scanning on the printing original plate P of UV light emitted from the UV lamp 40, the entire surface of the printing original plate can be irradiated with UV light in the same manner as the above-described inkjet head carriage 14.

  The UV ink Q formed as an image portion on the surface (recording surface) of the printing original plate P is cured by being irradiated with UV light emitted from the UV lamp 40. The printing original plate P whose image portion is cured by UV light emitted from the scanning UV irradiation unit 16 is further transported in the sub-scanning direction (X direction in FIG. 1) and transported to the next process or completed. It is discharged from the plate making apparatus 10 as a printing plate.

Here, the control unit 22 uses the head moving mechanism 18 and the light source unit moving mechanism 46 to move the head carriage 14 and the light source unit 38 in the main scanning direction at the same cycle and the positional relationship between the head carriage 14 and the light source unit 38. Move so as to be within a predetermined range.
Here, as the UV ink Q, a radical polymerization type ink is preferably used.
By using radical polymerization type ink as the UV ink Q, an image can be formed at a lower cost.

  The UV ink Q is preferably a radical polymerization type ink as described above, but the present invention is not limited to this, and various ultraviolet curable inks such as a cationic polymerization type ink can be used. .

  In the above embodiment, the wire reels 48a and 48b and the wire 50 are used as the light source unit moving mechanism 46, and both ends of the wire 50 are wound around the wire reels 48a and 48b, respectively. With such a configuration, only one drive source is required and the configuration is simple, so that there are advantages that the cost of the apparatus can be suppressed, and that operation control and maintenance are simple.

  However, the present invention is not limited to this, and various configurations can be adopted as long as the light source unit 38 can reciprocate in parallel with the platen 12. For example, by wrapping the endless wire 50 around the wire reels 48a and 48b, urging the wire reels 48a and 48b toward the outside of the transport path of the printing original P and rotating the wire 50 while applying tension, The light source unit 38 may be configured to reciprocate in the main scanning direction. Moreover, it can replace with the wire 50 and can also employ | adopt the transmission system by a belt or a chain. Alternatively, a mechanism using a rack and pinion, a self-propelled mechanism, or a linear motor may be used.

Here, in this embodiment, ultraviolet curable ink is used as the UV ink, but the present invention is not limited to this, and various active light curable inks that can use visible light and infrared light as curable light are used. Can be used.
Similarly, various active light sources that emit active light such as visible light can be used as the light source, that is, an active light irradiation unit can be used.

  Here, in the present invention, the “actinic ray” is not particularly limited as long as it can impart energy capable of generating a starting species in the ink by the irradiation, and is broadly divided into α rays, γ rays, X-rays, ultraviolet rays, visible rays, electron beams and the like are included. Among these, from the viewpoints of curing sensitivity and device availability, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable. Therefore, as the actinic ray curable ink, it is preferable to use an ultraviolet curable ink that can be cured by irradiating ultraviolet rays as in the present embodiment.

  As mentioned above, although one embodiment of the ink jet drawing apparatus and the ink jet drawing method of the present invention has been described in detail, the present invention is not limited to the above embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course you can go.

In each of the above-described embodiments, the scanning UV irradiation unit 16 is disposed downstream of the head carriage 14 in the feeding direction of the printing original P (sub-scanning (X) direction), but the present invention is not limited to this. The printing original plate P may be arranged upstream in the feeding direction (sub-scanning (X) direction).
For example, when a UV light source different from the scanning UV irradiation unit 16 is provided on the downstream side in the feeding direction of the printing original plate P with respect to the head carriage 14, the scanning UV irradiation unit 16 is disposed upstream in the feeding direction of the printing original plate P. It is preferable to arrange in.

  In addition, when pre-processing is performed prior to the ejection of the UV ink Q by the ink jet head 62, it is preferable that the scanning UV irradiation unit 16 be disposed downstream of the head carriage 14 in the feeding direction of the printing original P. Examples of the pretreatment include surface coating and plasma treatment for controlling the surface characteristics of the printing original plate P, such as wettability.

  In the above-described embodiment, the present invention is described in detail by giving an example in which the present invention is applied to the plate making apparatus 10 using the printing original plate P as a recording medium. However, the present invention is not limited to this, and various As described above, the present invention may be applied to a drawing apparatus and a recording medium.

  DESCRIPTION OF SYMBOLS 10 Plate making apparatus, 12 Platen, 14 Inkjet head carriage, 16 Scan type UV (ultraviolet) irradiation part, 18 Head movement mechanism, 20 Conveyance mechanism, 22 Control part, 24 Irradiation part movement mechanism, 30 Feed roller, 32 Stopping roller, 34 Drive screw, 35 guide rail, 36a drive support, 36b support, 38 light source unit, 40 UV (ultraviolet) lamp, 42 reflector, 42a exit, 46 light source unit moving mechanism, 47A, 47B mirror, 48a, 48b wire reel , 50 wires, 52 drive source (motor), 54 illumination window, 51 housing, 62 inkjet head, P recording medium.

Claims (3)

A platen for supporting a sheet-like recording medium;
A head carriage having an inkjet head that ejects actinic ray curable ink as droplets imagewise on the recording medium, a first mirror, and a second mirror;
A head moving mechanism for moving the head carriage in the main scanning direction;
An actinic ray irradiation unit that emits actinic rays;
An irradiation unit moving mechanism for moving the actinic ray irradiation unit in the main scanning direction;
A control unit;
With
The ink jet head is disposed between the first mirror and the second mirror in the main scanning direction of the head carriage;
The control unit is configured to irradiate an active ray from the actinic ray irradiating unit on a mirror located behind the head carriage in the moving direction of the first mirror or the second mirror and reflect the active ray from the mirror. An inkjet drawing apparatus, wherein the head moving mechanism and the irradiation unit moving mechanism are controlled so that the active light curable ink on the recording medium is irradiated with the active light.   The inkjet drawing apparatus according to claim 1, wherein the first mirror or the second mirror is arranged at a position higher than a nozzle surface of the inkjet head.   3. The inkjet drawing apparatus according to claim 1, wherein the actinic ray irradiation unit is disposed at a position higher than a nozzle surface of the inkjet head.

Images