JP2011240274A - Droplet discharge apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge apparatus, capable of controlling the position of a discharge object with high accuracy, and further capable of effectively cooling a portion irradiated by light.SOLUTION: The droplet discharge apparatus 1 includes: a discharge head 2 for discharging a photocurable liquid material; a supporting unit 4 for supporting the discharge object P of the discharge head 2; a cooling medium circulating unit 5 for circulating a cooling medium in a space between the supporting unit 4 and the discharge object P by a reduced pressure atmosphere; and a light source unit for irradiating the liquid material, which is discharged from the discharge head 2, by the light.

Description

  The present invention relates to a droplet discharge device.

  In recent years, attention has been focused on a droplet discharge device capable of forming a pattern by discharging ultraviolet curable ink from a discharge head. According to this droplet discharge device, the ink can be quickly cured by irradiating the ink discharged onto the discharge target with ultraviolet rays. Therefore, it becomes easy to form a three-dimensional molded product with ink, or to form a pattern on an ejection target having irregularities. In this technique, it is important to cool the portion irradiated with ultraviolet rays while controlling the position of the discharge target with respect to the droplet discharge device with high accuracy.

  In the following Patent Document 1, a plurality of three-dimensional printed materials (discharge objects) are attached to a flat bed that moves in a direction orthogonal to the moving direction of the printer head using a plurality of jigs. In the technique of Patent Document 1, a plurality of types of printed materials having different shapes can be fixed by exchanging a jig (adapter) according to the shape of the printed material.

  In the following Patent Document 2, a medium (ejection target) is adsorbed on a platen by a medium adsorbing means, and the medium is fixed. Further, the first medium cooling means circulates outside air for cooling over the inside and outside of the platen inner space to cool the medium.

JP 2007-136664 A JP 2005-153431 A

The conventional techniques as described above have the following problems.
For example, as in Patent Document 1, when a discharge target is fixed by a jig, the discharge head and the jig may interfere with each other. In addition, if the jig is changed to deal with different shapes of discharge objects, it is necessary to prepare a jig for each discharge object, which may reduce the convenience of the droplet discharge device.

  For example, when the outside air for cooling is circulated across the inside and outside of the platen inner space as in Patent Document 2, depending on the shape of the media, turbulence is generated by the air from the upper end of the platen to induce the flight of the droplets, There is a risk that the print quality is extremely lowered. That is, depending on the shape of the media, it may be difficult to fix the media or to cool it well. In addition, since the medium adsorbing means for adsorbing the media and the first media cooling means for cooling the media are provided, the apparatus configuration may be complicated.

  The present invention has been made in view of the above circumstances, and provides a droplet discharge device capable of controlling the position of a discharge target with high accuracy and effectively cooling a portion irradiated with light. One of the purposes is to do.

The present invention employs the following means in order to achieve the above object.
The droplet discharge device of the present invention includes a discharge head capable of discharging a photocurable liquid material, a support portion that supports a discharge target of the discharge head, and a space between the support portion and the discharge target. And a light source part for irradiating light to the liquid material discharged from the discharge head.

  In this case, since the light source unit that irradiates the discharged liquid material with light is provided, the liquid material can be quickly cured, and a three-dimensional molded product can be formed or the discharge target object having unevenness can be formed. It becomes easy to form a pattern on the surface. Since the refrigerant circulation part circulates the refrigerant in a reduced pressure atmosphere in the space between the support part and the discharge target object, the discharge target object can be adsorbed to the support part under reduced pressure, and the discharge target object and support can be supported by circulation of the refrigerant. The part can be cooled.

  Since the discharge target can be fixed to the support portion by vacuum suction, it is possible to save the trouble of preparing a fixing jig and to avoid interference between the droplet discharge device and the jig. In addition, since the discharge target and the support portion can be cooled, the temperature rise due to light irradiation or the like when curing the discharged liquid material can be suppressed, and the discharged liquid material or the droplet discharge device It is possible to avoid deterioration and deformation due to temperature rise of the member and the discharge target. As described above, according to the present invention, the position of the ejection target can be controlled with high accuracy, and the portion irradiated with light can be effectively cooled.

  The droplet discharge apparatus according to the present invention can take the following modes as typical modes.

The refrigerant circulation unit may be configured to depressurize the space more than between the discharge head and the discharge target.
If it does in this way, a discharge subject can be fixed to a support part with a pressure difference between the above-mentioned space between a discharge head and a discharge subject.

The aspect provided with the supply port which supplies the said refrigerant | coolant between the said support part and the said discharge target object, and the discharge port which discharges | emits the said refrigerant | coolant from between the said support part and the said discharge target object may be sufficient.
If it does in this way, a refrigerant | coolant can be distribute | circulated to this space, maintaining said space in a pressure-reduced atmosphere by discharging | emitting the refrigerant | coolant supplied from the supply port from the discharge port.

The support portion may be capable of rotating around an axis that intersects a discharge direction of the discharge head.
With this configuration, the posture of the discharge target with respect to the discharge head can be changed by the rotation of the support portion, and the liquid material can be discharged from the plurality of discharge directions with respect to the discharge target. Thereby, for example, according to the shape of the discharge object, the liquid material can be arranged on the discharge object in a multifaceted manner. In addition, since it is less necessary to change the posture of the discharge head itself, it is possible to avoid the occurrence of droplet flight bending due to a change in the posture of the discharge head.

An aspect in which the discharge operation of the discharge head is possible while the pressure reducing operation by the refrigerant circulation unit is being performed and the support unit is rotated around the axis is possible.
In this way, even when the support portion is rotated, the discharge target is adsorbed to the support under reduced pressure, so that the position of the discharge target with respect to the discharge head can be controlled with high accuracy.

It is a schematic block diagram which shows one Embodiment of a droplet discharge apparatus. (A) is a plan view of the carriage to which the ejection head is attached, and (b) is a side view of the carriage. (A) is a cutaway perspective view of the ejection head, and (b) is a cross-sectional view of the ejection head. It is sectional drawing which shows the structural example of a work stage. It is sectional drawing which shows the other structural example of a work stage.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used for explanation, in order to show characteristic parts in an easy-to-understand manner, dimensions and scales of structures in the drawings may be different from actual structures. In addition, in the embodiment, the same components are illustrated with the same reference numerals, and detailed description thereof may be omitted.

FIG. 1 is a schematic configuration diagram illustrating an embodiment of a droplet discharge device.
The droplet discharge device 1 shown in FIG. 1 can arrange (apply) droplets of an ultraviolet curable (photo-curable) liquid material on a discharge target P by a droplet discharge method. Further, the droplet discharge device 1 can form a desired film pattern by curing the liquid disposed on the discharge target P by ultraviolet irradiation (light irradiation).

  A droplet discharge device 1 shown in FIG. 1 includes a plurality of discharge heads 2, a carriage 3, a work stage 4 as a support portion, a coolant circulation portion 5, and a control portion 6. In the XYZ orthogonal coordinate system shown in FIG. 1, the X axis is parallel to the sub-scanning direction, the Y axis is parallel to the main scanning direction, and the Z axis is parallel to the ejection direction. Typically, the X-axis direction and the Y-axis direction are set to the horizontal direction, and the Z-axis direction is set to the vertical direction. In the following description, one of directions parallel to each axis may be referred to as a positive side and the other as a negative side.

  The work stage 4 is disposed on the upper surface of a base such as a surface plate, for example. The discharge target P is transported and placed on the work stage 4 by a transport robot or the like (not shown). The refrigerant circulation unit 5 circulates the refrigerant in the space between the discharge target P and the work stage 4 so that the discharge target P is detachably fixed to the work stage 4 by vacuum suction, and the discharge target P And the work stage 4 is cooled. The plurality of ejection heads 2 are held by the carriage 3 above the work stage 4. The control unit 6 controls the ejection operation of the ejection head 2 while controlling the relative position between the ejection target P and the ejection head 2.

Next, each component of the droplet discharge device 1 will be described in detail.
The carriage 3 is movably provided by a carriage moving unit (not shown). Here, the carriage 3 can be translated in the Y-axis direction, translated in the Z-axis direction, and rotated around the Z-axis. The control unit 6 controls the position of the carriage 3 by controlling the carriage moving unit, and substantially controls the positions of the plurality of ejection heads 2.

  The work stage 4 is provided so as to be movable by a stage moving unit (not shown). Here, the work stage 4 can be translated in the X axis direction, rotated around the X axis, and rotated around the Y axis. The control unit 6 controls the position of the work stage 4 by controlling the stage moving unit, and substantially controls the position of the discharge target P.

  As described above, the control unit 6 controls the stage moving unit and the carriage moving unit, thereby managing the relative positions of the discharge target P and the discharge head 2 in three directions in the XYZ axis direction and three directions around the XYZ axis. Is possible.

FIG. 2A is a plan view of the carriage to which the ejection head is attached as viewed from the upper surface side of the apparatus base, and FIG. 2B is a side view of the carriage.
In the present embodiment, a plurality (four in the drawing) of the ejection heads 2 are arranged in the Y-axis direction. The plurality of ejection heads 2 correspond to ink (liquid material) of key color (K) such as cyan (C), magenta (M), yellow (Y), and black. Each ejection head 2 includes a plurality of (for example, 180) nozzles N arranged in the X-axis direction. A plurality of nozzles N constitute a nozzle row NA. The discharge head 2 discharges a liquid droplet D from each nozzle N toward the discharge target P.

  The plurality of ejection heads 2 are supplied with a liquid material from a liquid material supply unit (not shown). The liquid supply unit includes a plurality of tanks and a piping system. Different liquids are stored in the plurality of tanks. Each tank is connected to each discharge head 2 by a piping system. Thereby, different liquid materials can be discharged from the plurality of discharge heads 2.

  Light source portions 21 are provided on both sides of each ejection head 2 in the Y-axis direction. The light source unit 21 includes, for example, an LED (light emitting diode), and irradiates the liquid disposed on the discharge target P with light L including light (ultraviolet light) having a wavelength for curing the liquid. The light source unit 21 is controlled by the control unit 6 to turn on and off.

  2A shows an example in which a plurality of nozzles N are arranged in a line in each discharge head 2, but the total number of nozzles N provided in the discharge head 2 and the nozzles N in the nozzle array NA are shown. The arrangement direction, the number of nozzles N included in each nozzle array NA, the number of nozzle arrays NA, and the like can be arbitrarily changed. Further, the number of ejection heads 2 arranged on the carriage 3 can be arbitrarily changed. Further, a plurality of carriages 3 may be provided for each sub-carriage. Further, the arrangement and configuration of the light source unit 21 can be changed as appropriate.

  3A is a cutaway perspective view of the ejection head, and FIG. 3B is a cross-sectional view of the ejection head. The plurality of ejection heads 2 have the same structure, and the structure of one ejection head 2 will be described as a representative of the plurality of ejection heads 2.

  The ejection head 2 includes a diaphragm 31, a nozzle plate 32, a reservoir 33, a partition wall 34, a plurality of cavities 35, and a plurality of piezoelectric elements 36. The diaphragm 31 is provided with a material supply hole 31a connected to the piping system of the liquid material supply unit. The nozzle plate 32 is made of, for example, SUS and has a nozzle surface 32a. The nozzle surface 32 a includes the open ends of a plurality of nozzles N. The partition wall 34 is provided so as to partition the diaphragm 31 and the nozzle plate 32 into a reservoir 33 and a plurality of cavities 35.

  Each nozzle N has a one-to-one correspondence with each cavity 35 and communicates with the corresponding cavity 35. Each piezoelectric element 36 has a one-to-one correspondence with each cavity 35. The piezoelectric element 36 is, for example, a piezoelectric element, and is provided on the side opposite to the cavity 35 with respect to the diaphragm 31. Each cavity 35 communicates with a plurality of cavities 35 through a common reservoir 33 and a supply path 35a. The reservoir 33 communicates with the material supply hole 31a. The liquid material supplied from the liquid material supply unit is stored in the reservoir 33 through the material supply hole 31a. The liquid material stored in the reservoir 33 is filled into each cavity 35 through the supply path 35a.

  As shown in FIG. 3B, the piezoelectric element 36 has a structure in which a piezoelectric material layer 37 is sandwiched between a pair of electrodes 38. When a voltage is applied to the pair of electrodes 38, the piezoelectric material layer 37 contracts or expands, and the piezoelectric element 36 deflects the diaphragm 31. Thereby, the volume of the cavity 35 increases or decreases. When the volume of the cavity 35 increases, the liquid material is filled into the cavity 35 from the reservoir 33. When the volume of the cavity 35 decreases, the liquid material in the cavity 35 is discharged as a droplet D from the nozzle N.

FIG. 4 is a diagram schematically showing a cross-sectional configuration of the work stage.
As shown in FIGS. 1 and 4, the work stage 4 has a plurality of recesses 41 formed on the surface on which the discharge target P is placed. A supply port 42 and a discharge port 43 are provided inside each recess 41. In addition, there is no limitation in the number of the recessed parts 41, and one may be sufficient in the end.

  The refrigerant circulation unit 5 is configured by a compressor, a decompression pump, or the like. A supply pipe 51 and a discharge pipe 52 are connected to the refrigerant circulation part 5. The refrigerant circulation unit 5 supplies outside air, liquid, or the like as the refrigerant Q to the supply pipe 51, and collects the refrigerant Q via the recess 41 from the discharge pipe 52. The refrigerant circulation part 5 may discharge the recovered refrigerant Q to the outside, or may be supplied again to the supply pipe 51 and circulated. When the refrigerant Q is circulated, a device for cooling the refrigerant Q before supply may be provided inside or outside the refrigerant circulation unit 5.

  In the refrigerant circulation section 5, the space between the discharge target P and the work stage 4 (concave portion 41) is lower than the space between the discharge head 2 and the discharge target P (hereinafter referred to as external space). In this way, the pressure of the refrigerant Q to be circulated is adjusted. The pressure difference between the external space and the recess 41 is set according to the weight of the discharge target P and the posture with respect to the direction of gravity so that the discharge target P can be fixed by this pressure difference.

  The supply pipe 51 of this embodiment branches into a plurality of branch pipes, and each branch pipe is connected to each supply port 42 of the work stage 4. A valve 53 is provided between each branch pipe of the supply pipe 51 and each supply port 42. Further, the discharge pipe 52 is branched into a plurality of branch pipes, and each branch pipe is connected to each discharge port 43 of the work stage 4. A valve 54 is provided between each branch pipe of the discharge pipe 52 and each discharge port 43.

  The valve 53 and the valve 54 are configured by, for example, electromagnetic valves, and the opening / closing thereof is individually controlled by the control unit 6 for each valve. Thereby, it becomes possible to select which of the recesses 41 of the work stage 4 the coolant Q is circulated in, for example, the recesses 41 positioned outside the bottom surface of the discharge target P according to the dimensions of the discharge target P. The refrigerant Q can be prevented from flowing.

  In order to form a planar pattern or a three-dimensional pattern on the ejection target P by the droplet ejection device 1 having the above configuration, first, the ejection target P is placed on the work stage 4. Then, the control part 6 controls the refrigerant circulation part 5 to make the inside of the concave part 41 of the work stage 4 have a reduced pressure atmosphere and to cause the refrigerant Q to circulate in the concave part 41. Accordingly, the discharge target P is fixed to the work stage 4 and the discharge target P and the work stage 4 can be cooled by the refrigerant Q.

  Then, liquid droplets D are ejected from the ejection head 2, and for example, each time the droplets D are ejected, the liquid L arranged on the ejection target P is irradiated with light L from the light source unit 21. Thereby, the liquid on the discharge target P is quickly cured, and dripping or the like is avoided. Further, a three-dimensional molded product can be formed by overlapping a plurality of patterns by discharging the liquid again on the pattern obtained by curing the liquid and discharging the liquid again and curing the liquid.

  By the way, if the light L is irradiated without cooling the discharge target P or the work stage 4, the discharge target P or the work stage 4 may be heated to about 200 ° C. to 500 ° C., for example. As described above, since the discharge target P and the work stage 4 can be cooled by the refrigerant Q, the temperature rise of the discharge target P and the work stage 4 can be suppressed, and the discharge target P and the work stage 4 can be controlled. Thermal deformation and thermal alteration can be suppressed.

  In addition, in order to form a pattern on the side surface of the discharge target P, the inside of the concave portion 41 of the work stage 4 is held in a reduced pressure atmosphere by the refrigerant circulation portion 5. Then, the work stage 4 is rotated in the rotational direction around the X axis or the rotational direction around the Y axis so that the side surface to be ejected faces the ejection head 2. Then, the liquid droplets D are discharged from the discharge head 2 in the same manner as described above, and the light L is irradiated from the light source unit 21 to the liquid disposed on the discharge target P. Since the discharge target P is adsorbed to the work stage 4 at a reduced pressure, even when the work stage 4 is tilted, the displacement of the discharge target P is avoided, and the relative position between the discharge target P and the discharge head 2 is determined. It can be controlled with high accuracy.

  As described above, in the droplet discharge device 1, the position of the discharge target P can be controlled with high accuracy, and the discharge target P and the work stage 4 irradiated with light can be effectively cooled. it can. Compared with a device that fixes a discharge object using a jig or the like, the necessity for preparing a jig is reduced, and the convenience of the device is increased. In addition, the configuration of the apparatus can be simplified as compared with the configuration in which the mechanism for fixing the discharge target is independent of the mechanism for cooling.

  Moreover, in the droplet discharge device 1, the posture of the discharge target P with respect to the discharge head 2 can be changed, and the liquid material can be discharged from the discharge target P from a plurality of discharge directions. . Thereby, for example, according to the shape of the discharge target P, the liquid material can be arranged on the discharge target P in a multifaceted manner, and various patterns can be formed. In addition, since it is less necessary to change the posture of the discharge head 2 itself, it is possible to avoid the occurrence of the flying curve of the droplet due to the change in the posture of the discharge head 2.

  The technical scope of the present invention is not limited to the above embodiment. Various modifications are possible without departing from the gist of the present invention. Next, another aspect of the work stage will be described.

FIG. 5 is a cross-sectional view showing another configuration example of the work stage.
A work stage 4B shown in FIG. 5 is different from the work stage 4 of the above-described embodiment in that no recess is formed. In this example, the discharge target P has a recess, and the recess is placed facing the work stage 4B. The refrigerant circulation unit 5 supplies the refrigerant Q from the supply port 42 into the recess of the discharge target P in a reduced pressure atmosphere, and collects the refrigerant Q passing through the recess from the discharge port 43. Even in the droplet discharge device provided with such a work stage 4B, the discharge target P can be cooled while fixing the discharge target P as in the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 2 ... Discharge head, 3 ... Carriage,
4, 4B ... Work stage (supporting part), 5 ... Refrigerant circulation part, 6 ... Control part,
21 ... light source part, 31 ... diaphragm, 31a ... material supply hole,
32 ... Nozzle plate, 32a ... Nozzle surface, 33 ... Reservoir,
34 ... partition wall, 35 ... cavity, 35a ... supply path, 36 ... piezoelectric element,
37 ... Piezoelectric material layer, 38 ... Electrode, 41 ... Recess, 42 ... Supply port,
43 ... discharge port, 51 ... supply piping, 52 ... discharge piping,
53, 54 ... Valve, D ... Droplet, L ... Light, N ... Nozzle,
NA: Nozzle array, P: Discharge target, Q: Refrigerant

Claims (5)

An ejection head capable of ejecting a photocurable liquid material;
A support portion for supporting the discharge target of the discharge head;
A refrigerant circulation part that circulates the refrigerant in a reduced-pressure atmosphere in a space between the support part and the discharge object;
A light source unit that emits light to the liquid material ejected from the ejection head;
A droplet discharge device comprising:   The liquid droplet ejection device according to claim 1, wherein the refrigerant circulation part decompresses the space more than between the ejection head and the ejection object.   The supply port which supplies the said refrigerant | coolant between the said support part and the said discharge target object, and the discharge port which discharges | emits the said refrigerant | coolant from between the said support part and the said discharge target object are provided. 3. A droplet discharge device according to 2.   4. The droplet discharge device according to claim 1, wherein the support portion is rotatable around an axis that intersects a discharge direction of the discharge head. 5.   The droplet discharge device according to claim 4, wherein the discharge operation of the discharge head is possible while the pressure reducing operation by the refrigerant circulation portion is being performed and the support portion is rotated around the axis.

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