Jetting device

Abstract

The present invention provides a jetting device with which jetting stability can be improved.　This jetting device is for jetting a thermoplastic material onto a jet-receiving medium, and comprises: a metal support part that supports the jet-receiving medium; a syringe having at the tip a nozzle that jets the thermoplastic material onto the jet-receiving medium; a power source that applies a voltage between the nozzle and the support part; an insulating part provided on the outer circumference of the syringe; a first heating part provided on the outer circumference of the insulating part; a second heating part that heats the nozzle indirectly; and a control device, wherein the control device causes the thermoplastic material to be jetted onto the jet-receiving medium from the nozzle while a voltage is applied between the nozzle and the support part by the power source.

Description

Discharge device

[0001] The present disclosure relates to a dispensing device that dispenses a thermoplastic material onto a receiving medium.

[0002] Conventionally, an inkjet recording method has been known in which a voltage pulse is applied between a recording electrode of a recording head and a counter electrode on a recording medium, and the resulting electrostatic force (Coulomb force) causes ink to fly from an orifice in the recording head onto the recording medium to form an image (Patent Document 1). In the invention described in this document, a temperature control means is provided on the recording medium side to control the surface temperature of the recording medium, thereby controlling the temperature of the ink flying from the orifice and adhering to the recording medium. The above document also describes providing a heater in the orifice and controlling the temperature of the heater.

[0003] Patent No. 2853517

[0004] However, while the above prior art inventions are configured to provide a heater in the orifice and control the heater temperature, there is a risk that the ink may not be heated enough to melt when using highly viscous ink, and there is also a risk that the thermoplastic material may not land in the desired position. Therefore, there is room for improvement in ejection stability.

[0005] Therefore, an object of the present disclosure is to provide a discharge device that can improve the stability of discharge.

[0006] The ejection device disclosed herein is an ejection device that ejects a thermoplastic material onto an ejection medium, and includes a metal support part that supports the ejection medium, a syringe having a nozzle at its tip that ejects the thermoplastic material onto the ejection medium, a power source that applies a voltage between the nozzle and the support part, an insulating part provided on the outer periphery of the syringe, a first heating part provided on the outer periphery of the insulating part, a second heating part that indirectly heats the nozzle, and a control device, wherein the control device ejects the thermoplastic material from the nozzle onto the ejection medium while the power source applies a voltage between the nozzle and the support part.

[0007] According to the present disclosure, an insulating portion is provided on the outer periphery of the syringe. This makes it difficult for electrostatic force, generated when a voltage is applied between the nozzle and the support portion from a power source, to be transmitted to the first heating portion via the syringe. This reduces the risk of damage to the first heating portion due to electrostatic force. Furthermore, electrostatic force is more easily applied to the thermoplastic material ejected from the nozzle, thereby increasing the likelihood that the thermoplastic material will land at the desired position on the ejection medium. Furthermore, the nozzle can be indirectly heated to a high temperature by the second heating portion. This allows the temporarily solidified thermoplastic material to be steadily melted within the nozzle before being ejected. As a result, the ejection stability of the thermoplastic material is improved. Furthermore, as described above, the configuration in which the second heating portion indirectly heats the nozzle allows for effective heating of the nozzle, even if the nozzle has a shape that makes it difficult to attach a heating portion, such as a conical shape.

[0008] The ejection device disclosed herein is an ejection device that ejects a thermoplastic material onto a metal receiving medium, and includes a syringe having a nozzle at its tip that ejects the thermoplastic material onto the receiving medium, a power source that applies a voltage between the nozzle and the receiving medium, an insulating section provided on the outer periphery of the syringe, a first heating section provided on the outer periphery of the insulating section, a second heating section that indirectly heats the nozzle, and a control device, wherein the control device ejects the thermoplastic material from the nozzle onto the receiving medium while the power source applies a voltage between the nozzle and the receiving medium.

[0009] According to the present disclosure, the same effects as those described above can be achieved, and further, by having the ejected medium act as an electrode, the support part becomes unnecessary, and it becomes possible to use a material other than metal as the support part.

[0010] According to the present disclosure, it is possible to provide a discharge device that can improve the stability of discharge.

[0011] It is a schematic diagram showing the configuration of a discharge device according to an embodiment.It is a block diagram showing the configuration of the discharge device of Figure 1.It is a schematic diagram showing the configuration of a discharge device according to an embodiment.

[0012] Hereinafter, a discharge device according to an embodiment of the present disclosure will be described with reference to the drawings. The discharge device described below is merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiment, and additions, deletions, and modifications are possible within the scope of the present disclosure.

[0013] Fig. 1 is a schematic diagram showing the configuration of a discharge device 100 according to an embodiment of the present invention. Fig. 2 is a block diagram showing the configuration of the discharge device 100 shown in Fig. 1.

[0014] The ejection device 100 ejects a thermoplastic material (so-called hot-melt ink, which is solid at room temperature and melts when heated) onto an ejection receiving medium W. After the thermoplastic material is ejected onto the ejection receiving medium W, it solidifies on the ejection receiving medium W, thereby achieving printing. Conventional hot-melt inks can be used, including those containing oil-soluble dyes of various colors, such as black, cyan, magenta, and yellow, a fatty acid that dissolves or disperses the oil-soluble dyes, a mixed solvent consisting of an organic solvent such as polyethylene or a mixture thereof, an antioxidant, a preservative, a polymerization inhibitor, and the like. An example of the ejection receiving medium W is a metal plate.

[0015] As shown in Fig. 1, the discharge device 100 includes a syringe 2 having a nozzle 1, a support unit 3, a power source 4, a ceramic tube 5, a tube heater 6, an infrared heater 7, a first temperature controller 9, a second temperature controller 10, a reflecting unit 11, a temperature sensor 12, an air pressure supply system 20, and a control device 30. As shown in Fig. 2, the discharge device 100 further includes a drive circuit 40, a drive unit 41, a third temperature controller 42, and a heater 43. The ceramic tube 5 corresponds to an insulating unit, the tube heater 6 corresponds to a first heating unit, and the infrared heater 7 corresponds to a second heating unit.

[0016] The syringe 2 extends in a predetermined direction and is formed in a cylindrical shape. The syringe 2 has a nozzle 1 at its tip. At least a portion of the outer surface of the nozzle 1 is black. A supply pipe (not shown) is connected to the syringe 2. Thermoplastic material is supplied into the syringe 2 through this supply pipe. The thermoplastic material supplied into the syringe 2 is discharged from the nozzle 1 towards the discharge medium W. An air pressure supply system 20 is also connected to the syringe 2. The air pressure supply system 20 will be described in detail later. Note that in this embodiment, a drive unit (not shown) may be provided that moves the syringe 2 back and forth in three axial directions. This makes it possible for the tip of the nozzle 1 to move closer to or farther away from the support unit 3.

[0017] The support unit 3 supports the ejection receiving medium W. The support unit 3 is made of metal. The support unit 3 is capable of reciprocating movement in three axial directions by a drive unit 41 including, for example, a ball screw or a rack and pinion. This allows the support unit 3 to move closer to or farther away from the tip of the nozzle 1. Note that it is only necessary for the support unit 3 to be able to move relatively closer to or farther away from the tip of the nozzle 1, so it is sufficient to provide at least one of the drive unit and drive unit 41.

[0018] Furthermore, the support part 3 is provided with a temperature sensor 12. The temperature sensor 12 detects the temperature of the support part 3. Temperature information of the support part 3 detected by the temperature sensor 12 is sent to the first temperature controller 9.

[0019] The power supply 4 is, for example, a high-voltage power supply, and applies a voltage between the nozzle 1 and the support portion 3. The power supply 4 is connected to the nozzle 1 by an electric wire 4a, and is also connected to the support portion 3 by an electric wire 4b. As a result, a predetermined voltage is applied between the nozzle 1 and the support portion 3, and the thermoplastic material in the syringe 2 is ejected onto the ejection receiving medium W so as to be attracted to the support portion 3, as will be described later.

[0020] The ceramic tube 5 is provided on the outer periphery of the syringe 2. Specifically, the ceramic tube 5 is wound around the outer periphery of the syringe 2. The ceramic tube 5 has a thermal conductivity higher than 1 W / (m·k). A material having high thermal conductivity and insulating properties is used as the insulating portion.

[0021] The tube heater 6 is provided on the outer periphery of the ceramic tube 5. Specifically, the tube heater 6 is wound around the outer periphery of the ceramic tube 5. An example of the tube heater 6 is an electric heater made of ceramic. The second temperature controller 10 is connected to the tube heater 6 by a power supply line 10a and is also connected to the tube heater 6 by a temperature control line 10b. This supplies power to the tube heater 6, and the second temperature controller 10 controls the heating of the tube heater 6. Therefore, the heat from the tube heater 6 is conducted to the syringe 2 via the ceramic tube 5, thereby heating the syringe 2.

[0022] Infrared heater 7 indirectly heats nozzle 1 and syringe 2. Infrared heater 7 has a heating element 8, such as a halogen lamp, and a reflecting mirror 18, such as a semicircular mirror, arranged behind heating element 8. First temperature controller 9 is connected to heating element 8 by a power supply line 9b and to temperature sensor 12 by a temperature control line 9a. This allows power to be supplied to heating element 8, and first temperature controller 9 controls the heat generation of heating element 8. Therefore, nozzle 1 and syringe 2 are heated by infrared rays from heating element 8. In this case, reflecting mirror 18 reflects the infrared rays from heating element 8 toward nozzle 1. This makes it easier for nozzle 1 and syringe 2 to be heated.

[0023] The reflecting portion 11 reflects the infrared rays emitted by the heating element 8 toward the nozzle 1. Furthermore, the reflecting portion 11 focuses the infrared rays emitted by the heating element 8 toward the nozzle 1. The reflecting portion 11 is formed, for example, in an arc shape. The reflecting portion 11 is disposed, for example, on the outer side in the radial direction of the nozzle 1. The reflecting portion 11 is provided so as to surround the nozzle 1 from the radial direction of the nozzle 1.

[0024] The air pressure supply system 20 includes a compressor 21, a regulator filter 22, a pressure gauge 23, and an air supply pipe 24. The compressor 21 compresses the outside air it takes in and introduces the compressed air into the air supply pipe 24. The regulator filter 22 removes water droplets, dust, and the like contained in the compressed air and reduces the pressure of the compressed air to a predetermined pressure. The pressure gauge 23 measures the pressure of the compressed air flowing through the air supply pipe 24. The downstream end of the air supply pipe 24 is connected to the inside of the syringe 2. In this configuration, the compressed air generated by the compressor 21 is supplied into the syringe 2 via the air supply pipe 24. As a result, the thermoplastic material in the syringe 2 is pushed out by the compressed air and ejected from the nozzle 1 onto the ejection receiving medium W. By supplying compressed air into the syringe 2 in this way, it is also possible to eject the thermoplastic material onto the ejection receiving medium W.

[0025] 2, the control device 30 has a calculation unit 31, a storage unit 32, and an interface 33. The control device 30 may be a single controller or may be configured with multiple controllers.

[0026] The interface 33 is connected to an external device 34 such as a computer, a network, or a recording medium, and receives various data such as print data from the external device 34. The print data is data for forming an image by discharging the thermoplastic material onto the discharge receiving medium W. Note that the print data may be data stored in the storage unit 32, or may be data input by the user using an input device 35 such as a keyboard and mouse provided in the discharge device 100.

[0027] The storage unit 32 is a storage medium accessible by the calculation unit 31, and is composed of, for example, RAM and ROM. The RAM temporarily stores various data. Examples of this data include print data and data calculated by the calculation unit 31. The ROM stores programs for performing various processes. Note that the programs may be stored in a storage medium other than the storage unit 32.

[0028] The calculation unit 31 is configured by a processor such as a CPU and an integrated circuit such as an ASIC, etc. The calculation unit 31 executes various controls by executing programs stored in a ROM.

[0029] The control device 30 is connected to the drive unit 41 via the drive circuit 40, and outputs a control signal based on print data to the drive circuit 40. The drive circuit 40 generates a drive signal based on the control signal and outputs it to the drive unit 41. This causes the drive unit 41 to drive the support unit 3 in accordance with the drive signal. In this case, the drive unit 41 moves the support unit 3 so that the position of the ejection receiving medium W in the three axial directions relative to the nozzle 1 is a predetermined position.

[0030] The control device 30 controls the application of voltage by the power supply 4. The control device 30 ejects the thermoplastic material from the nozzle 1 onto the ejection receiving medium W while applying a voltage between the nozzle 1 and the support part 3 by the power supply 4. When a predetermined voltage is applied between the nozzle 1 and the support part 3 by the power supply 4, an electric field (electrostatic field) is generated between the nozzle 1 and the support part 3. At this time, an electrostatic force (Coulomb force) in the electric field is applied to the thermoplastic material in the syringe 2. As a result, the thermoplastic material in the syringe 2 is ejected onto the ejection receiving medium W so as to be attracted to the support part 3.

[0031] In this embodiment, the control device 30 applies a voltage between the nozzle 1 and the support part 3 using the power source 4, causing the thermoplastic material in the syringe 2 to be ejected from the nozzle 1 onto the ejected medium W, but in addition, the ejection of the thermoplastic material by the nozzle 1 may be assisted by supplying compressed air into the syringe 2 using the air pressure supply system 20.

[0032] After the thermoplastic material is ejected from the nozzles 1 onto the ejection receiving medium W as described above, the control device 30 causes the drive circuit 40 to continuously move the support part 3 that supports the ejection receiving medium W in two axial directions, i.e., in a plane. As a result, the thermoplastic material is drawn in lines on the ejection receiving medium W.

[0033] Here, in order to improve the accuracy of the landing position of the thermoplastic material ejected from the nozzle 1 on the ejection receiving medium W, it is necessary to control the strength of the electric field that is generated between the nozzle 1 and the support part 3 when a voltage is applied between the nozzle 1 and the support part 3 by the power supply 4. In this regard, if the strength of the electric field is small, the landing position of the thermoplastic material will not be accurate, and if the strength of the electric field is large, a discharge phenomenon will occur between the nozzle 1 and the support part 3. Therefore, in this embodiment, the range of the electric field strength is set as follows:

[0034] When a voltage is applied between the nozzle 1 and the support portion 3 by the power supply 4, the electric field E generated between the nozzle 1 and the support portion 3 is expressed as V / d [kV / mm], where V [kV] is the voltage and d [mm] is the distance between the tip of the nozzle 1 and the support portion 3. In this case, the control device 30 controls either the application operation of the power supply 4, the drive operation of the drive portion 41, or the application operation of the power supply 4 and the drive operation of the drive portion 41 so as to satisfy the relationship 0.2<V / d<2 (hereinafter referred to as the relational expression). Control by the control device 30 as described above improves the accuracy of the landing position of the thermoplastic material ejected from the nozzle 1 on the ejection receiving medium W.

[0035] The strength of the electrostatic force caused by the electric field controlled by the control device 30 based on the above relational expression is sufficiently large compared to the frictional force of the thermoplastic material against the inner surface of the nozzle 1 when it is ejected from the nozzle 1 and the tension of the thermoplastic material. Furthermore, even when ejection receiving media W of different shapes are used, the control device 30 may control the application operation, etc. of the power source 4 based on the above relational expression. Furthermore, the control device 30 may control the application operation, etc. of the power source 4 based on the above relational expression depending on whether or not the discharge phenomenon occurs.

[0036] The control device 30 transmits control signals to the first temperature controller 9, the second temperature controller 10, and the third temperature controller 42. The first temperature controller 9 controls the heat generation of the heating element 8 of the infrared heater 7 based on the detection result of the temperature sensor 12 in accordance with the control signal from the control device 30. This heats the nozzle 1 to a predetermined temperature. The second temperature controller 10 controls the heating of the tube heater 6 in accordance with the control signal from the control device 30. This heats the syringe 2, and the thermoplastic material in the syringe 2 reaches a predetermined temperature.

[0037] The heater 43 heats the ejection receiving medium W and the support unit 3. The heater 43 may be provided, for example, on the surface of the support unit 3 opposite to the surface that supports the ejection receiving medium W. The third temperature controller 42 controls the heating of the heater 43 in accordance with a control signal from the control device 30. As a result, the ejection receiving medium W and the support unit 3 are heated to a predetermined temperature. The control device 30 also controls the pressure reduction operation by the regulator filter 22 based on the measurement results from the pressure gauge 23.

[0038] Fig. 3 is a schematic diagram showing the configuration of a discharge device 100 according to another embodiment. As shown in Fig. 3, in this embodiment, a power source 4 is connected to the nozzle 1 by an electric wire 4a and to the metallic discharge receiving medium W by an electric wire 4b. Other points are the same as those in Fig. 1, and therefore a description thereof will be omitted.

[0039] 3, instead of applying a voltage between the nozzle 1 and the support part 3 as in Fig. 1, the power supply 4 applies a voltage between the nozzle 1 and the ejection receiving medium W in accordance with instructions from the control device 30. With the power supply 4 applying a voltage between the nozzle 1 and the ejection receiving medium W, the control device 30 causes the thermoplastic material to be ejected from the nozzle 1 onto the ejection receiving medium W.

[0040] As described above, according to the ejection device 100 of this embodiment, the ceramic tube 5 is wrapped around the outer periphery of the syringe 2. Therefore, the electrostatic force generated when the power supply 4 applies voltage between the nozzle 1 and the support unit 3 (or between the nozzle 1 and the ejection receiving medium W) is less likely to be conducted to the tube heater 6 via the syringe 2. This prevents damage to the tube heater 6. Furthermore, electrostatic force is more likely to act on the thermoplastic material ejected from the nozzle 1, thereby increasing the likelihood that the thermoplastic material will land at the desired position on the ejection receiving medium W. Furthermore, the infrared rays from the infrared heater 7 can indirectly heat the nozzle 1 to a high temperature. This allows the thermoplastic material to be steadily melted within the nozzle 1 before ejection, even if it is temporarily solidified before ejection. This improves the stability of the ejection of the thermoplastic material. Furthermore, since the configuration in which the infrared heater 7 indirectly heats the nozzle 1 is adopted as described above, the nozzle 1 can be effectively heated even if it has a shape that makes it difficult to attach a heating means, such as a conical shape.

[0041] In this embodiment, the reflecting portion 11 is provided so as to surround the nozzle 1 from the radial direction of the nozzle 1. The reflecting portion 11 reflects and condenses the infrared rays from the heating element 8 toward the nozzle 1, thereby making it possible to heat the nozzle 1 and the syringe 2 more efficiently with the infrared rays.

[0042] In this embodiment, at least a part of the outer surface of the nozzle 1 is black, which makes it easier for the nozzle 1 to absorb heat, thereby making the nozzle 1 more efficiently heated.

[0043] Furthermore, in this embodiment, the heater 43 heats the ejection receiving medium W and the support part 3. This allows the thermoplastic material ejected from the nozzle 1 to land on the ejection receiving medium W and adhere to the ejection receiving medium W at the same time.

[0044] In this embodiment, the ceramic tube 5 has a thermal conductivity higher than 1 W / (m·k), which allows the heat from the tube heater 6 to be efficiently transferred to the syringe 2 via the ceramic tube 5.

[0045] Furthermore, in this embodiment, the power supply 4 may apply a voltage between the nozzle 1 and the metallic ejection receiving medium W in accordance with instructions from the control device 30. In this case, the control device 30 causes the power supply 4 to apply a voltage between the nozzle 1 and the ejection receiving medium W, and causes the thermoplastic material to be ejected from the nozzle 1 onto the ejection receiving medium W. According to this aspect, the support part 3 that supports the ejection receiving medium W does not have to be made of metal, and the support part 3 can be made of, for example, resin, which widens the range of materials that can be used for the support part 3.

[0046] Furthermore, in this embodiment, the control device 30 controls the application operation of the power source 4 and the drive operation of the drive unit 41 so that 0.2<V / d<2 is satisfied. This makes it possible to increase the accuracy of the landing position of the thermoplastic material ejected from the nozzle 1 onto the ejection receiving medium W, without causing a discharge phenomenon in the thermoplastic material.

[0047] The present disclosure is not limited to the above-described embodiment. Although several modifications have been given in the above-described embodiment, the following modifications can also be adopted without departing from the spirit of the present disclosure.

[0048] In the above embodiment, the nozzle 1 is indirectly heated by infrared rays from the infrared heater 7, but this is not limiting. Instead of or in addition to the infrared rays from the infrared heater 7, the nozzle 1 may be indirectly heated by laser irradiation.

[0049] In the above embodiment, the nozzle 1 is heated by the infrared heater 7, but this is not limiting. For example, the nozzle 1 may be formed into a cylindrical shape including the tip of the nozzle 1, and a heater may be wrapped around the outer periphery of the nozzle 1 to heat the nozzle 1 and apply an electrostatic force to it.

[0050] Furthermore, in the above embodiment, the ceramic tube 5 is used as the insulating portion, but instead of the ceramic tube 5, for example, a rubber material or the like may be used.

[0051] Furthermore, in the above embodiment, the air pressure supply system 20 is provided, but the air pressure supply system 20 is not an essential component.

[0052] The above-described embodiments should be construed as examples only, and are provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure.

[0053] REFERENCE SIGNS LIST 1 nozzle 2 syringe 3 support portion 4 power supply 5 ceramic tube 6 tube heater 7 infrared heater 8 heating element 11 reflecting portion 18 reflecting mirror 20 air pressure supply system 30 control device 41 driving portion 43 heater 100 ejection device W ejection receiving medium

Claims

1. An ejection device that ejects a thermoplastic material onto a receiving medium, comprising: a metal support part that supports the receiving medium; a syringe having a nozzle at its tip that ejects the thermoplastic material onto the receiving medium; a power source that applies a voltage between the nozzle and the support part; an insulating part provided on the outer periphery of the syringe; a first heating part provided on the outer periphery of the insulating part; a second heating part that indirectly heats the nozzle; and a control device, wherein the control device ejects the thermoplastic material from the nozzle onto the receiving medium while the power source applies a voltage between the nozzle and the support part.

2. The ejection device according to claim 1, wherein the second heating section is an infrared heater that heats the nozzle with infrared rays, and further comprises a reflecting section that reflects the infrared rays toward the nozzle.

3. The dispensing device of claim 1, wherein at least a portion of the outer surface of the nozzle is black.

4. The ejection device according to claim 1, further comprising a heater that heats the ejection receiving medium or the support portion.

5. The discharge device according to claim 1, wherein the insulating portion has a thermal conductivity higher than 1 W / (m·k).

6. The ejection device according to claim 1, which is an ejection device that ejects the thermoplastic material onto the ejection receiving medium made of metal, wherein the power source applies a voltage between the nozzle and the ejection receiving medium instead of applying a voltage between the nozzle and the support part, and the control device ejects the thermoplastic material from the nozzle onto the ejection receiving medium while the power source applies a voltage between the nozzle and the ejection receiving medium.

7. The discharge device according to claim 1, further comprising a drive unit that moves the support unit relatively closer to or farther away from the tip of the nozzle, wherein an electric field E generated between the nozzle and the support unit when a voltage is applied by the power supply is expressed as V / d [kV / mm], where V [kV] is the voltage and d [mm] is the distance between the tip of the nozzle and the support unit, and wherein the control device controls either one of the application operation of the power supply, the operation of the drive unit, or the application operation of the power supply and the operation of the drive unit so that 0.2<V / d<2.

8. An ejection device that ejects a thermoplastic material onto a metallic ejection medium, comprising: a syringe having a nozzle at its tip that ejects the thermoplastic material onto the ejection medium; a power source that applies a voltage between the nozzle and the ejection medium; an insulating section provided on the outer periphery of the syringe; a first heating section provided on the outer periphery of the insulating section; a second heating section that indirectly heats the nozzle; and a control device, wherein the control device ejects the thermoplastic material from the nozzle onto the ejection medium while the power source applies a voltage between the nozzle and the ejection medium.

9. The ejection device according to claim 8, wherein the second heating section is an infrared heater that heats the nozzle with infrared rays, and further comprises a reflecting section that reflects the infrared rays toward the nozzle.

10. The dispensing device of claim 8, wherein at least a portion of the outer surface of the nozzle is black.

11. The ejection device according to claim 8, further comprising a heater for heating the ejection receiving medium.

12. The discharge device according to claim 8, wherein the insulating portion has a thermal conductivity higher than 1 W / (m·k).

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