Control device and inkjet printing apparatus

Abstract

The control device includes: a plurality of circuit boards; a plurality of heat conduction parts which are connected with the plurality of circuit substrates; and at least one cooling unit that is disposed on one end side in the width direction of the plurality of circuit substrates and cools the plurality of circuit substrates via the plurality of heat transfer units, the plurality of circuit substrates being disposed so as to be offset from each other in the width direction.

Description

Technical Field

[0001] The present disclosure relates to a control device and an inkjet printing device. Background Art

[0002] For most devices or equipment, heat dissipation countermeasures for circuit substrates are an important issue. Generally speaking, in a control box or the like that houses multiple circuit substrates, the following air cooling method is adopted to improve heat dissipation efficiency: multiple circuit substrates are arranged sufficiently apart from each other, and air is sent from a cooling fan arranged nearby for cooling. In addition, in such an air cooling method, a heat dissipation fan is also provided for the part that generates more heat or is not heat-resistant to dissipate heat.

[0003] However, depending on the device, due to the limitation of the installation space, it is necessary to stack a plurality of identical circuit substrates. In this case, it is sometimes impossible to install a cooling fan or a heat dissipation fan on each circuit substrate for air cooling. In this case, the circuit substrate is cooled by liquid cooling using water or the like as a refrigerant. In addition, liquid cooling is sometimes used in equipment where airflow generated by air cooling is not desired, such as equipment installed in a clean room.

[0004] As a technology of a liquid cooling mechanism for a unit having a structure formed by stacking a plurality of identical circuit substrates, for example, Patent Document 1 discloses a cooling mechanism comprising: a stacked unit formed by alternately stacking a plurality of semiconductor modules and a plurality of coolers having a flow path for a refrigerant; and a refrigerant supply and discharge pipe for supplying the refrigerant to the plurality of the coolers or discharging the refrigerant.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6206359 Summary of the invention

[0008] A control device involved in one scheme of the present disclosure comprises: a plurality of circuit substrates; a plurality of heat-conducting parts connected to the plurality of circuit substrates; and at least one cooling part, which is arranged on one end side in the width direction of the plurality of circuit substrates, and cools the plurality of circuit substrates via the plurality of heat-conducting parts, and the plurality of circuit substrates are arranged to be staggered with respect to each other in the width direction.

[0009] An inkjet printing device involved in one embodiment of the present invention includes multiple inkjet heads and a control device, wherein the control device includes: multiple circuit substrates, which are used to control at least one of the multiple inkjet heads; multiple heat-conducting parts, which are connected to the multiple circuit substrates; and at least one cooling part, which is arranged on one end side in the width direction of the multiple circuit substrates, and the multiple circuit substrates are cooled via the multiple heat-conducting parts, and the multiple circuit substrates are arranged to be staggered in the width direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic cross-sectional view of the control device according to the first embodiment.

[0011] Figure 2 It is an enlarged cross-sectional view of the boundary between the circuit board and the heat transfer portion according to the first embodiment.

[0012] Figure 3 This is an enlarged cross-sectional view of a structure in which a viscous body is provided at a boundary between a circuit substrate and a heat conducting portion according to the first embodiment.

[0013] Figure 4 It is a schematic cross-sectional view of a control device according to a modified example of the first embodiment.

[0014] Figure 5 It is a schematic cross-sectional view of a control device according to a second embodiment.

[0015] Figure 6 It is an enlarged cross-sectional view of a boundary between a circuit board and a heat transfer portion according to the second embodiment.

[0016] Figure 7 This is a schematic diagram of the control device according to the sixth embodiment as viewed from one side in the width direction.

[0017] Figure 8 It is a schematic cross-sectional view showing a state where the heat transfer part and the cooling part are connected by screws.

[0018] Fig. 9 It is a schematic cross-sectional view showing a state where the heat transfer part and the cooling part are connected by screws.

[0019] Fig.10 It is a schematic cross-sectional view showing a state where a heat transfer unit and a cooling unit in the sixth embodiment are connected by screws.

[0020] Fig.11 This is a schematic diagram of a control device according to a modification of the sixth embodiment as viewed from one side in the width direction.

[0021] Fig.12This is a schematic diagram showing the flow of a refrigerant in a cooling unit when the control device according to the tenth embodiment is viewed from one side in the width direction.

[0022] Fig.13 This is a schematic diagram showing the flow of the refrigerant in the cooling unit when the control device according to the modification example of the tenth embodiment is viewed from one side in the width direction.

[0023] Fig.14 This is a schematic diagram showing the flow of the refrigerant in the cooling unit when a control device according to another modified example of the tenth embodiment is viewed from one side in the width direction. DETAILED DESCRIPTION

[0024] In the cooling mechanism disclosed in Patent Document 1, a cooling pipe for passing a refrigerant is sandwiched between stacked circuit substrates. Therefore, when one or more circuit substrates need to be replaced due to a failure, the replacement cannot be performed without separating the cooling pipe adjacent to the circuit substrate to be replaced. Therefore, the replacement procedure is complicated, and when separating the cooling pipe, if the refrigerant is not sufficiently removed in advance, the circuit substrate will be wetted by the refrigerant leaking from the cooling pipe, which may damage the circuit substrate.

[0025] An object of the present disclosure is to provide a control device and an inkjet printing device having good heat dissipation characteristics and maintainability.

[0026] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings as appropriate. It should be noted that, regarding the description of the drawings in the specification, for substantially the same components, the same reference numerals are given and repeated descriptions are omitted.

[0027] [First embodiment]

[0028] First, a first embodiment of the present disclosure will be described. Figure 1 is a cross-sectional schematic diagram of the control device. Figure 2 This is an enlarged cross-sectional view of the boundary between the circuit board and the heat conducting portion. Figure 3 This is an enlarged cross-sectional view of a structure in which a viscous body is provided at the boundary between a circuit substrate and a heat conducting portion. Figure 4 It is a schematic cross-sectional view of a control device according to a modified example.

[0029] like Figure 1 As shown in FIG. 1 , the control device 1 includes a plurality of circuit boards 2, a plurality of heat conducting parts 3, a low heat conducting part 4, and a cooling part 5. Each component is described below. Figure 1In the prescribed figures, the X axis represents the width direction of the circuit board 2, the Y axis represents the thickness direction of the circuit board 2, and the Z axis represents the depth direction of the circuit board 2. In addition, the arrangement relationship of each structure is sometimes described using expressions such as the width direction, the thickness direction, or the depth direction.

[0030] The control device 1 includes five circuit substrates 2. The five circuit substrates 2 are arranged at positions offset from each other in the width direction. Hereinafter, the five circuit substrates 2 are sometimes referred to as the first circuit substrate 21, the second circuit substrate 22, the third circuit substrate 23, the fourth circuit substrate 24, and the fifth circuit substrate 25. It should be noted that the number of circuit substrates 2 is not limited to five as long as it is a plurality of circuit substrates. In addition, the circuit substrate 2 disclosed in the present invention is not particularly limited to the purpose as long as it enables a plurality of circuit substrates 2 having the same structure to function as a whole and is used for purposes where the circuit substrates 2 cannot be fully separated from each other due to the relationship of the installation space. As an example of the use of the circuit substrate 2, the control of an inkjet head constituting an industrial inkjet printing device can be exemplified.

[0031] In order to increase the printing speed, an industrial inkjet printing device arranges a plurality of inkjet heads to form a line head, and uses a plurality of nozzles arranged in the width direction of the printing object to print the printing object through a single scan, thereby increasing the printing speed. In order to perform high-precision printing, a plurality of nozzles need to be arranged at a high density. Therefore, due to the restriction of the arrangement of the nozzles, the inkjet head, and more specifically, the circuit substrate 2 of the inkjet head, cannot be arranged sufficiently separately. In addition, in the case where it is necessary to control the strength of the signal for ejecting droplets from the inkjet head for each individual nozzle, it is necessary to configure an amplifying circuit for the ejection signal corresponding to the number of nozzles on the circuit substrate 2, so that the structure of the circuit substrate 2 becomes large-scale and complicated, and the heat generated by the circuit substrate 2 may also increase.

[0032] The heat conducting part 3 is formed into a plate shape using a material with high thermal conductivity. The control device 1 has six heat conducting parts 3. Hereinafter, the six heat conducting parts 3 are sometimes referred to as the first heat conducting part 31, the second heat conducting part 32, the third heat conducting part 33, the fourth heat conducting part 34, the fifth heat conducting part 35 and the sixth heat conducting part 36. The heat conducting part 3 is arranged in a manner of surrounding the circuit substrate 2 between adjacent circuit substrates 2. The heat conducting part 3 is thermally connected to the circuit substrate 2 so that the heat generated from the circuit substrate 2 is transferred to the heat conducting part 3 as a whole. Two of the six heat conducting parts 3 are fixed to two surfaces of a circuit substrate 2. The remaining four heat conducting parts 3 are respectively fixed to a single surface of a circuit substrate 2. For example, the first and second heat conducting parts 31 and 32 are fixed to two surfaces of the first circuit substrate 21, and the third to sixth heat conducting parts 33 to 36 are fixed to a single surface of the second to fifth circuit substrates 22 to 25. In this way, a circuit board 2 and a heat transfer part 3 fixed to one or both surfaces of the circuit board 2 constitute a cooled part to be cooled by the cooling part 5. In such a cooled part, the heat transfer part 3 functions as a housing of the circuit board 2. The cooled parts are configured to be attachable to and detachable from each other.

[0033] The low heat conduction portion 4 is formed in a layered form by a material having a lower thermal conductivity than the heat conduction portion 3. Figure 1 As shown, the low heat conduction portion 4 is formed on the surface of the heat conduction portion 3 facing the circuit substrate 2. The interval between the adjacent circuit substrates 2 is very small, so the heat generated in the circuit substrate 2 (for example, the third circuit substrate 23) heats the adjacent circuit substrates 2 (for example, the second and fourth circuit substrates 22 and 24) through the heat conduction portion 3 in contact with the circuit substrate 2. In addition, due to the heat generated from the portion (hereinafter sometimes referred to as the concentrated heat generation portion 7) of the electrical structural element 8 arranged on the circuit substrate 2 with a large amount of heat, for example, the third heat conduction portion 33 or the fourth heat conduction portion 34 adjacent to the third circuit substrate 23 is locally heated to a high temperature, and the second circuit substrate 22 or the fourth circuit substrate 24 adjacent to the high temperature portion is heated. Therefore, for example, by using the low heat conduction portion 4 formed on the surface of the third heat conduction portion 33 facing the third circuit substrate 23, the heat of the concentrated heat generation portion 7 of the third circuit substrate 23 is temporarily dispersed in the horizontal direction including the width direction and the depth direction. Then, the third heat transfer portion 33 suppresses the dispersed heat from being transferred to the second circuit board 22 .

[0034] The cooling part 5 is composed of a cooling part having a refrigerant flow path 51. The cooling part 5 is configured in a manner of contacting a contact surface 301 which is one end surface of the heat conducting part 3 in the width direction, that is, a surface which is not opposite to the circuit substrate 2. Since the low heat conduction part 4 is not formed between the heat conducting part 3 and the cooling part 5, heat cannot be efficiently transferred from the heat conducting part 3 to the cooling part 5. The heat transferred from the heat conducting part 3 to the cooling part 5 is removed by the liquid refrigerant flowing in the refrigerant flow path 51. In addition, by adopting a structure in which a plurality of heat conducting parts 3 are in contact with one cooling part 5, the number of cooling parts 5 can be made less than the number of circuit substrates 2, thereby simplifying the structure of the refrigerant flow path 51.

[0035] It should be noted that in Figure 1 In the embodiment, a structure is adopted in which five circuit substrates 2 are cooled by one cooling unit 5, but there is no limitation on the relationship between the number of circuit substrates 2 and the number of cooling units 5. For example, four cooling units 5 may be in contact with 40 circuit substrates 2, that is, ten circuit substrates 2 may be in contact with one cooling unit 5, and the groups may be arranged into four groups, thereby forming a mechanism for cooling 40 circuit substrates 2. In addition, in order not to hinder the transfer of heat to the refrigerant, the material of the cooling unit 5 is preferably a material with a high thermal conductivity, preferably a metal with a high thermal conductivity such as copper or aluminum, or an alloy such as brass. In addition, since the refrigerant is in contact with the refrigerant, the refrigerant flow path 51 may also be subjected to a surface treatment for corrosion protection.

[0036] like Figure 2 As shown, various electrical structural elements 8 are mounted on the surface (one side in the thickness direction) of the circuit substrate 2. In this way, the circuit substrate 2 having the concave-convex corresponding to the electrical structural element 8 on the surface can be provided with a heat conducting portion 3 having the concave-convex corresponding to the concave-convex, thereby reducing the gap between the circuit substrate 2 and the low thermal conductivity portion 4, thereby improving the thermal conductivity between the circuit substrate 2 and the heat conducting portion 3. In addition, due to the deviation in the processing of at least one of the circuit substrate 2 and the heat conducting portion 3, the contact state or the size of the gap between the two will also vary. In order to prevent the quality of the control device 1 from fluctuating due to such deviation in the contact state or the size of the gap, as shown in FIG. Figure 3 As shown, a thermally conductive viscous body 9 made of a heat dissipation gel or a heat dissipation paste may be disposed between the circuit board 2 and the low thermal conductive portion 4 .

[0037] Next, the function and effect of the control device 1 of the first embodiment will be described. Since the configuration of the electrical components 8 mounted on the plurality of circuit substrates 2 is the same, the concentrated heat generating portion 7 of each circuit substrate 2 is generated at the same place of each circuit substrate 2. Therefore, if the plurality of circuit substrates 2 are simply stacked, the concentrated heat generating portions 7 of each other are close to each other, and the temperature rise of the close portions becomes larger. Figure 1As shown, in the control device 1 of the first embodiment, the plurality of circuit substrates 2 are arranged at positions staggered in the width direction, so the positions of the concentrated heat generating portions 7 of the adjacent circuit substrates 2 are staggered and separated in the width direction, so that the temperature rise near the concentrated heat generating portions 7 can be suppressed. Therefore, the heat of the control device 1 can be efficiently released by the cooling portion 5. In addition, since the cooling portion 5 is not arranged between the adjacent circuit substrates 2 but is arranged at one end side in the width direction of the plurality of circuit substrates 2, when the circuit substrate 2 constituting a part of the control device 1 is replaced, the cooling portion 5 can be easily removed from the circuit substrate 2, and the circuit substrate 2 can be suppressed from being wetted by the refrigerant leaking from the cooling portion 5. Thus, a control device 1 having good heat dissipation characteristics and maintainability can be provided.

[0038] In addition, by arranging the plurality of circuit substrates 2 at positions staggered in the width direction, the plurality of heat conducting parts 3 can also be arranged at positions staggered in the width direction. Therefore, the contact surface 301 of the heat conducting part 3 that contacts the cooling part 5 can be set as a surface inclined with respect to the vertical direction. Therefore, compared with the case where the contact surface 301 is set as a surface parallel to the vertical direction, the area of ​​the contact surface 301 can be increased, and the heat can be transferred from the heat conducting part 3 to the cooling part 5 more efficiently.

[0039] In particular, since the plurality of cooled portions including one circuit board 2 and the heat transfer portion 3 fixed to one or both surfaces of the circuit board 2 are configured to be independently attachable and detachable, the user can easily remove the circuit board 2 from the control device 1 .

[0040] Next, a modified example of the control device 1 of the first embodiment will be described. Figure 4 As shown, the control device 1A has a structure in which two cooling parts 5 are arranged so as to contact the inclined contact surface 301 at one end side in the width direction of the heat conducting part 3 and the contact surface 302 at the other end side which is inclined in the same manner as the contact surface 301. If such a structure is adopted, the heat dissipation efficiency of the control device 1A can be improved.

[0041] [Second embodiment]

[0042] Next, a second embodiment of the present disclosure will be described. Figure 5 is a cross-sectional schematic diagram of the control device. Figure 6 It is an enlarged cross-sectional view of the boundary between the circuit substrate and the heat conducting part. It should be noted that the same names and the same reference numerals are given to the same structures as those of the control device 1 of the first embodiment, and the description is simplified or omitted. In addition, the number of each component is not limited to the number described below, and can also be other numbers.

[0043] like Figure 5 As shown in FIG. 1 , the control device 1B includes five circuit substrates 2 arranged at positions offset from each other in the width direction, ten heat conducting portions 3B, a low heat conducting portion 4, and two cooling portions 5. Hereinafter, the ten heat conducting portions 3B may be referred to as a first heat conducting portion 31B, a second heat conducting portion 32B, a third heat conducting portion 33B, a fourth heat conducting portion 34B, a fifth heat conducting portion 35B, a sixth heat conducting portion 36B, a seventh heat conducting portion 37B, an eighth heat conducting portion 38B, a ninth heat conducting portion 39B, and a tenth heat conducting portion 40B.

[0044] Two heat conducting parts 3B are fixed to two surfaces of one circuit substrate 2. For example, the first and second heat conducting parts 31B and 32B are fixed to two surfaces of the first circuit substrate 21, and the ninth and tenth heat conducting parts 39B and 40B are fixed to two surfaces of the fifth circuit substrate 25. In this way, a circuit substrate 2 and the heat conducting parts 3B fixed to two surfaces of the circuit substrate 2 constitute a cooled part cooled by the cooling part 5. In such a cooled part, the heat conducting part 3B functions as a shell of the circuit substrate 2. Each cooled part is configured to be detachable from each other. The mutually opposing surfaces of the adjacent heat conducting parts 3B are formed in a flat shape.

[0045] One cooling unit 5 is disposed so as to contact a contact surface 301B which is one end surface of the heat transfer unit 3B in the width direction. The other cooling unit 5 is disposed so as to contact a contact surface 302B which is the other end surface of the heat transfer unit 3B in the width direction.

[0046] like Figure 6 As shown, an electrical structural element 8a is arranged on one side of the circuit substrate 2, and an electrical structural element 8b is arranged on the other side. In this case, the heat generating portion is located on both sides of the circuit substrate 2. The cooled portions adjacent to each other are arranged in a manner to form a gap C therebetween. For example, the cooled portion including the third circuit substrate 23 and the cooled portion including the fourth circuit substrate 24 are arranged in a manner to form a gap C between the sixth heat conducting portion 36B and the seventh heat conducting portion 37B. It should be noted that a gap C may also be arranged between the circuit substrate 2 and the low heat conducting portion 4. Figure 3 The viscous body 9 is shown.

[0047] According to the second embodiment, since the heat transfer portions 3B are disposed on both surfaces of the circuit board 2 , heat generated from either surface of the circuit board 2 can be effectively removed.

[0048] Furthermore, since the gap C is formed between the adjacent cooled portions, the heat transfer between the adjacent heat transfer portions 3B can be suppressed by the heat insulating effect of the air present in the gap C.

[0049] In addition, since the opposing surfaces of the adjacent heat conducting parts 3B are formed into a flat surface, when the cooled part including the specified circuit substrate 2 is moved toward the front side or the inner side in the depth direction to be removed from the control device 1, it can be easily removed without interfering with other cooled parts.

[0050] [Third embodiment]

[0051] Next, a third embodiment of the present disclosure will be described. The control device of the third embodiment is based on the control device 1 of the first embodiment or the control device 1B of the second embodiment, and has a structure in which the heat conducting parts 3 and 3B are formed of metal and the heat conducting parts 3 and 3B are fixed to the cooling part 5 by screws. As the material of the heat conducting parts 3 and 3B, metals such as iron, aluminum, and copper, or alloys such as brass can be used, but it is not limited to this.

[0052] According to the third embodiment, by forming the heat transfer parts 3 and 3B with metal, the thermal conductivity of the heat transfer parts 3 and 3B can be improved, and the heat dissipation efficiency of the control device 1 can be further improved.

[0053] Furthermore, even if the positions of the contact surfaces 301 of the plurality of heat transfer parts 3 or the positions of the contact surfaces 301B and 302B of the plurality of heat transfer parts 3B are slightly offset due to processing deviation, by tightening the screws, the contact surfaces 301, 301B and 302B of the plurality of heat transfer parts 3 and 3B are pressed against the outer peripheral surface of the cooling part 5, which is the same surface, so that the contact surfaces 301, 301B and 302B can conform to the outer peripheral surface of the cooling part 5 by utilizing the flexibility of the metal, and the contact surfaces 301, 301B and 302B can be reliably brought into contact with the cooling part 5. Therefore, by using a simple screw tightening method, the heat dissipation efficiency of the control device 1 can be further improved.

[0054] In addition, by screwing the heat conducting parts 3, 3B and the cooling part 5, the circuit board 2 can be easily removed from the control device, thereby improving the maintainability. In addition, by using the high axial force of the screw to press the heat conducting parts 3, 3B and the cooling part 5, stable high thermal conductivity can be obtained.

[0055] [Fourth embodiment]

[0056] Next, a fourth embodiment of the present disclosure will be described. The control device of the fourth embodiment is the control device 1 of the first embodiment or the control device 1B of the second embodiment, and has a structure in which the low heat conductive portion 4 is formed of resin.

[0057] According to the fourth embodiment, by forming the low thermal conductive portion 4 with resin, it is possible to suppress the transfer of heat from the thermal conductive portion 3 or 3B heated by the heat generated from the circuit board 2 to the circuit board 2 adjacent to the circuit board 2 .

[0058] [Fifth Embodiment]

[0059] Next, a fifth embodiment of the present disclosure will be described. The control device of the fifth embodiment is the control device 1 of the first embodiment or the control device 1B of the second embodiment, and has a structure in which a low heat conductive portion 4 is formed by insulating coating.

[0060] As the material of the insulating coating, acrylic, epoxy, urethane, polyimide and the like can be cited. Here, since the low thermal conductivity portion 4 is the portion receiving heat from the circuit substrate 2, it is preferred that the heat resistance is high. In addition, when the control device 1, 1B is used in an industrial inkjet printing device, resistance to the solvent of the ink is also required. In consideration of these necessary characteristics, as the material of the insulating coating, it is preferred to use a material such as a polyimide that has both insulation, heat resistance and chemical resistance, but it is not limited thereto.

[0061] In addition, as a method for forming an insulating coating, electrodeposition coating, spray coating, electrostatic coating, powder coating, etc. can be listed. Here, when the concave and convex corresponding to the electrical structural elements 8, 8a, 8b of the circuit substrate 2 are set on the heat conducting part 3, 3B, it is necessary to set a coating film corresponding to the concave and convex. In addition, for each of the multiple heat conducting parts 3, 3B, or within the surface of the heat conducting part 3, 3B, if there is a deviation in the thermal conductivity of the low heat conducting part 4, the heat dissipation characteristics will be deviated, so the uniformity of the thickness of the coating film is required. In consideration of these necessary matters, as a method for forming an insulating coating, it is preferred to use electrodeposition coating, but it is not limited to this.

[0062] According to the fifth embodiment, by forming the low thermal conductive portion 4 by insulating coating, the electrodes and wiring portions on the circuit board 2 can be insulated from the thermal conductive portions 3 and 3B, thereby preventing a short circuit from occurring on the circuit board 2 .

[0063] [Sixth embodiment]

[0064] Next, a sixth embodiment of the present disclosure will be described. Figure 7 This is a schematic diagram of the control device viewed from one side in the width direction. Fig.11This is a schematic diagram of the control device involved in the modification example observed from one side in the width direction. It should be noted that the same names and the same reference numerals are given to the same structures as those of the control device 1 of the first embodiment, and the description is simplified or omitted. In addition, the number of each component is not limited to the number described below, and may be other numbers.

[0065] Figure 7 The control device 1C shown has a structure in which a plurality of cooling units 5C are in contact with the contact surfaces 301 of the heat transfer units 3 of the control device 1 of the first embodiment. Figure 7 Although not shown in the figure, the other structures of the control device 1C are the same as those of the control device 1 of the first embodiment.

[0066] The control device 1C includes, for example, two cooling units 5C. Hereinafter, the two cooling units 5C are sometimes referred to as a first cooling unit 5C1 and a second cooling unit 5C2, respectively. The first cooling unit 5C1 is arranged in contact with the contact surfaces 301 of the first to sixth heat transfer units 31 to 36. The second cooling unit 5C2 is arranged on one side ( Figure 7 The first cooling unit 5C1 and the second cooling unit 5C2 are combined to form a size that is the same as the size of the cooling unit 5 of the first embodiment. Figure 7 In the example, the structure in which two cooling parts 5C are in contact with six heat transfer parts 3 is shown, but the number of cooling parts 5C can be plural, and three or more may be sufficient.

[0067] Each heat conducting part 3 is preferably fixed to the first and second cooling parts 5C1 and 5C2 by screws. With such a structure, the circuit substrate 2 can be easily removed from the control device 1C, thereby improving the maintainability. In addition, by using the high axial force of the screws to press each heat conducting part 3 and the first and second cooling parts 5C1 and 5C2, stable high thermal conductivity can be obtained.

[0068] According to the sixth embodiment, since the first and second cooling parts 5C1 and 5C2 are in contact with the first to sixth heat transfer parts 31 to 36, the contact area between each heat transfer part 3 and the first cooling part 5C1 or the second cooling part 5C2 can be reduced compared with the structure of the first embodiment. Therefore, even if the contact surface 301 of each heat transfer part 3 has unevenness due to processing deviation, the reliability of the contact between each heat transfer part 3 and the first and second cooling parts 5C1 and 5C2 is improved, and poor contact is not likely to occur. As a result, the reduction in the heat dissipation efficiency of the control device 1C can be suppressed.

[0069] Figure 84 is a cross-sectional schematic diagram showing a state where the heat conducting part and the cooling part are connected by screws. When the heat conducting part 3 and the cooling part 5C are connected by screws 400 as in the first embodiment, even if the contact surface 301 of the heat conducting part 2 has unevenness such as warping, the cooling part 5C can be slightly bent by the axial force of the screws 400 in a manner conforming to the shape of the contact surface 301 of the heat conducting part 3, thereby improving the reliability of contact.

[0070] On the other hand, Fig. 9 As shown, the structure of the sixth embodiment is effective when the desired contact area cannot be ensured only by the axial force of the screw 400 because the cooling portion 5C is a member that is not easily bent or the axial force of the screw 400 is weak. Fig.10 As shown, if the cooling portion 5C is divided into the first cooling portion 5C1 and the second cooling portion 5C2, the gap between the contact surface 301 and the first cooling portion 5C1 and the second cooling portion 5C2 becomes smaller, so that the contact area can be increased by the axial force of the screw 400. In addition, there is also a case where the cooling portion 5C is warped. In this case, as long as the cooling portion 5C is divided, the contact area can also be increased by the axial force of the screw.

[0071] Next, a modification of the control device 1C according to the sixth embodiment will be described. Fig.11 The control device 1D shown in the figure has a structure in which four cooled parts composed of a circuit substrate 2 and a heat conducting part 3 fixed to a single surface of the circuit substrate 2 are further arranged in the control device 1 of the first embodiment, and the contact surface 301 of each heat conducting part 3 is respectively in contact with a plurality of cooling parts 5D. The four additional cooled parts are stacked on Figure 1 Hereinafter, the heat transfer part 3 included in the four additional cooled parts may be referred to as the seventh, eighth, ninth, and tenth heat transfer parts 37 , 38 , 39 , and 40 .

[0072] The control device 1D, for example, includes five cooling units 5D. Hereinafter, the five cooling units 5D are sometimes referred to as the first cooling unit 5D1, the second cooling unit 5D2, the third cooling unit 5D3, the fourth cooling unit 5D4, and the fifth cooling unit 5D5. The control device 1D is configured in such a way that the combinations of cooling units 5D that abut against the first to tenth heat transfer units 31 to 40 are different. Specifically, the first cooling unit 5D1 is configured in such a way as to contact the contact surface 301 of the first to fifth heat transfer units 31 to 35. The second cooling unit 5D2 is disposed on one side ( Fig.11 The third cooling portion 5D3 is disposed on one side (the lower side) in the depth direction relative to the first cooling portion 5D1 so as to contact the contact surface 301 of the sixth to tenth heat transfer portions 36 to 40. Fig.11 The fourth cooling part 5D4 is configured in a manner of contacting the contact surfaces 301 of the third to eighth heat conducting parts 33 to 38 on one side in the thickness direction relative to the third cooling part 5D3. The fifth cooling part 5D5 is configured in a manner of contacting the contact surfaces 301 of the ninth and tenth heat conducting parts 39 and 40 on one side in the thickness direction relative to the fourth cooling part 5D4. According to such a structure, all the heat conducting parts 3 and the cooling part 5D are integrated and fixed, so that the control device 1D as a whole can be treated as a whole, and the strength of the control device 1D as a whole can be improved.

[0073] It should be noted that Fig.11 The structure of the cooling part 5D abutting against the first to sixth heat transfer parts 31 to 36 or the first to tenth heat transfer parts 31B to 40B shown in the figure is different from that shown in the figure. The control devices 1 and 1B of the first and second embodiments may also be used. Figure 7 The same structure as the combination of the cooling portion 5D in contact with the first to tenth heat transfer portions 31B to 40B shown is applied to the control device 1B of the second embodiment.

[0074] [Seventh embodiment]

[0075] Next, a seventh embodiment of the present disclosure will be described. The control device of the seventh embodiment has a configuration in which heat transfer parts 3 and 3B are connected to a frame ground in addition to the control device 1 of the first embodiment or the control device 1B of the second embodiment.

[0076] When the control device 1, 1B is driven, when electromagnetic waves are generated from the electrical structural elements 8, 8a, 8b of the circuit substrate 2, the electromagnetic waves become noise, which may have an adverse effect on the circuit substrate 2 adjacent to the circuit substrate 2. In the seventh embodiment, by connecting the heat conducting portion 3, 3B located between the circuit substrates 2 to the frame ground, the heat conducting portion 3, 3B can function as an electromagnetic wave shielding member of the circuit substrate 2. Therefore, the noise from the adjacent circuit substrates 2 can be blocked, so that the operation of each circuit substrate 2 can be stabilized. Therefore, the situation where excess heat is generated from each circuit substrate 2 can be suppressed, so that the heat dissipation efficiency of the control device 1, 1B can be further improved.

[0077] [Eighth Embodiment]

[0078] Next, an eighth embodiment of the present disclosure will be described. The control device of the eighth embodiment has a configuration in which a cooling unit 5 is connected to a frame ground in addition to the control device 1 of the first embodiment or the control device 1B of the second embodiment.

[0079] In the case where the refrigerant flowing in the cooling unit 5 is water, if the potential of the metal constituting the surface of the cooling unit 5 is on the oxidation side compared to the inherent potential of the metal, the metal on the surface of the cooling unit 5 will be ionized and dissolved into the refrigerant, thereby causing corrosion. In the eighth embodiment, by connecting the cooling unit 5 to the frame ground, the potential of the cooling unit 5 relative to the refrigerant can be controlled, thereby preventing the ionization of the metal on the surface of the cooling unit 5. Therefore, even if water with high cooling performance is used as the refrigerant, the corrosion of the cooling unit 5 can be suppressed.

[0080] [Ninth embodiment]

[0081] Next, the ninth embodiment of the present disclosure will be described. The control device of the eighth embodiment is based on the control device 1 of the first embodiment or the control device 1B of the second embodiment, and has a structure in which the heat transfer part 3, 3B is softer than the cooling part 5. As a method for realizing such a structure, a method of using a metal softer than the metal constituting the cooling part 5 to constitute the heat transfer part 3, 3B can be cited. The heat transfer part 3, 3B and the cooling part 5 are fixed with screws.

[0082] According to the ninth embodiment, when the heat conducting parts 3 and 3B are pressed against the cooling part 5 by tightening the screws, the positions of the contact surfaces 301 of the plurality of heat conducting parts 3 or the positions of the contact surfaces 301B and 302B of the plurality of heat conducting parts 3B are shifted, the cooling part 5 is not deformed, and on the other hand, the contact surfaces 301, 301B and 302B are plastically deformed and conform to the outer peripheral surface of the cooling part 5, whereby the contact surfaces 301, 301B and 302B are in contact with the cooling part 5. Therefore, when the heat conducting parts 3 and 3B are replaced during maintenance, the contact surfaces 301, 301B and 302B of the heat conducting parts 3 and 3B can be brought into contact with the cooling part 5 that is not deformed, so that the contact surfaces 301, 301B and 302B can be easily brought into close contact with the cooling part 5. Therefore, stable high thermal conductivity can be obtained. It should be noted that even if the heat transfer parts 3 and 3B are deformed to conform to the cooling part 5, this will not be a problem because it is a part that is removed during replacement.

[0083] It should be noted that, in order to make the heat transfer part 3, 3B softer than the cooling part 5, a surface treatment to increase the hardness may be performed on the contact part of the cooling part 5 with the heat transfer part 3, 3B. Such surface treatments include heat treatments or plating treatments that do not hinder the movement of heat.

[0084] [Tenth embodiment]

[0085] Next, a tenth embodiment of the present disclosure will be described. Fig.12It is a schematic diagram showing the flow of the refrigerant in the cooling unit when the control device is viewed from one side in the width direction. Fig.13 This is a schematic diagram showing the flow of the refrigerant in the cooling unit when the control device according to the modification example is viewed from one side in the width direction. Fig.14 Schematic diagram showing the flow of refrigerant in the cooling unit when observing the control device involved in another modified example from one side in the width direction. It should be noted that the same names and the same figure marks are given to the same structures as the control device 1 of the first embodiment, and the description is simplified or omitted. In addition, the number of each component is not limited to the number described below, and it can also be another number. In addition, the structure shown below can also be applied to the control device 1B of the second embodiment.

[0086] Fig.12 The control device 1E shown has the same structure as the control device 1 of the first embodiment, except that a cooling unit 5E is provided instead of the cooling unit 5. The cooling unit 5E is provided in a manner of contacting the contact surfaces 301 of the six heat transfer units 3 arranged in one direction. The cooling unit 5E includes a refrigerant flow path 51E, and the refrigerant flow path 51E includes a first flow path 51E1, a second flow path 51E2, and a third flow path 51E3.

[0087] The first flow path 51E1 is configured to allow the refrigerant R to flow along a first direction D1, which is parallel to the thickness direction and runs from the first heat transfer part 31 at one end side in the thickness direction (arrangement direction) toward the sixth heat transfer part 36 at the other end side. The second flow path 51E2 is directly connected to the downstream end of the first flow path 51E1. The second flow path 51E2 is configured to allow the refrigerant R to flow along a second direction D2, which runs from the sixth heat transfer part 36 toward the first heat transfer part 31 and is inclined relative to the thickness direction. The third flow path 51E3 is connected to the downstream end of the second flow path 51E2. The third flow path 51E3 is configured to allow the refrigerant R to flow along the first direction D1.

[0088] In the refrigerant flow path 51E of such a structure, the refrigerant R flowing in from the inlet 52E1 formed at the upstream end of the first flow path 51E1 passes through the first, second, and third flow paths 51E1, 51E2, and 51E3, and flows out from the outlet 52E2 formed at the downstream end of the third flow path 51E3. Due to the heat transferred from the heat transfer part 3, the temperature of the refrigerant R flowing in the refrigerant flow path 51E increases as it goes downstream. Therefore, the heat transfer efficiency of the refrigerant R flowing in the refrigerant flow path 51E from the downstream side heat transfer part 3 is lower than the heat transfer efficiency of the heat transfer part 3 from the upstream side.

[0089] In the tenth embodiment, the refrigerant flow path 51E is formed by the first flow path 51E1, the second flow path 51E2, and the third flow path 51E3. Therefore, the heat transfer efficiency from the downstream heat transfer part 3 (for example, the fourth heat transfer part 34) in the refrigerant R flowing in the first flow path 51E1 is lower than the heat transfer efficiency from the upstream heat transfer part 3 (for example, the third heat transfer part 33). On the other hand, the heat transfer efficiency from the downstream heat transfer part 3 (for example, the third heat transfer part 33) in the refrigerant R flowing in the second flow path 51E2 is lower than the heat transfer efficiency from the upstream heat transfer part 3 (for example, the fourth heat transfer part 34). In this way, for example, the heat transfer efficiency from the fourth heat transfer part 34 to the refrigerant is lower than the third heat transfer part 33 with respect to the refrigerant R flowing in the first flow path 51E1, and on the other hand, it is higher than the third heat transfer part 33 with respect to the refrigerant R flowing in the second flow path 51E2. Therefore, it is possible to suppress variations in heat transfer efficiency between the first to sixth heat transfer parts 31 to 36 and the refrigerant R, and thus it is possible to suppress variations in cooling effects on the first to sixth heat transfer parts 31 to 36 .

[0090] Next, a modification of the control device 1 according to the tenth embodiment will be described.

[0091] Fig.13 The control device 1F shown has the same configuration as the control device 1E of the tenth embodiment except that a cooling unit 5F is provided instead of the cooling unit 5E. The cooling unit 5F includes a refrigerant flow path 51F including a first flow path 51F1, a second flow path 51F2, and a third flow path 51F3.

[0092] The first flow path 51F1 is configured to allow the refrigerant R to flow in a first direction D1 from the first heat transfer part 31 at one end side in the thickness direction toward the sixth heat transfer part 36 at the other end side. The third flow path 51F3 is connected to the downstream end of the first flow path 51F1. The third flow path 51F3 is configured to allow the refrigerant R to flow in a third direction D3 parallel to the depth direction. The second flow path 51F2 is connected to the downstream end side of the first flow path 51F1 via the third flow path 51F3. The second flow path 51F2 is configured to allow the refrigerant R to flow in a fourth direction D4, which is from the sixth heat transfer part 36 toward the first heat transfer part 31 and is parallel to the thickness direction.

[0093] In the refrigerant flow path 51F having such a structure, the refrigerant R flowing in from the inlet 52F1 formed at the upstream end of the first flow path 51F1 passes through the first, third, and second flow paths 51F1, 51F3, and 51F2, and flows out from the outlet 52F2 formed at the downstream end of the second flow path 51F2. Fig.13In the illustrated structure, for example, the heat transfer efficiency from the fourth heat transfer part 34 to the refrigerant is lower than that of the third heat transfer part 33 with respect to the refrigerant R flowing in the first flow path 51F1, but is higher than that of the third heat transfer part 33 with respect to the refrigerant R flowing in the second flow path 51F2. Therefore, the variation in the cooling effect on the first to sixth heat transfer parts 31 to 36 can be suppressed.

[0094] Fig.14 The control device 1G shown has the same configuration as the control device 1E of the tenth embodiment except that a cooling unit 5G is provided instead of the cooling unit 5E. The cooling unit 5G includes a coolant flow path 51G, and the coolant flow path 51G includes a first flow path 51G1 and a second flow path 51G2.

[0095] The first flow path 51G1 is configured to allow the refrigerant R to flow in a first direction D1 from the first heat transfer part 31 at one end in the thickness direction toward the sixth heat transfer part 36 at the other end. The second flow path 51G2 is not connected to the first flow path 51G1. The second flow path 51G2 is configured to allow the refrigerant R to flow in a fourth direction D4 from the sixth heat transfer part 36 toward the first heat transfer part 31.

[0096] In the refrigerant flow path 51G of such a structure, the refrigerant R flowing in from the inlet 52G1 formed at the upstream end of the first flow path 51G1 flows out from the outlet 52G2 formed at the downstream end of the first flow path 51G1. In addition, the refrigerant R flowing in from the inlet 52G3 formed at the upstream end of the second flow path 51G2 flows out from the outlet 52G4 formed at the downstream end of the second flow path 51G2. Fig.14 In the illustrated structure, for example, the heat transfer efficiency from the fourth heat transfer part 34 to the refrigerant is lower than that of the third heat transfer part 33 with respect to the refrigerant R flowing in the first flow path 51G1, but is higher than that of the third heat transfer part 33 with respect to the refrigerant R flowing in the second flow path 51G2. Therefore, it is possible to suppress the variation in the cooling effect on the first to sixth heat transfer parts 31 to 36.

[0097] [Eleventh Embodiment]

[0098] Next, the eleventh embodiment of the present disclosure is described. The eleventh embodiment is an inkjet printing device having the control device 1 of the first embodiment or the control device 1B of the second embodiment. The inkjet printing device has a plurality of inkjet heads. Each circuit substrate 2 of the control devices 1 and 1B controls at least one inkjet head. The control devices 1 and 1B have a liquid cooling mechanism instead of an air cooling mechanism, so the problems caused by the air cooling mechanism can be avoided.

[0099] Specifically, as a problem caused by the air cooling mechanism, there is, for example, the influence of the air flow cooled by air on the ejected droplets of the inkjet. The inkjet droplets are very small, especially if high-precision inkjet printing is to be performed, the droplet size is even smaller, and a typical example of the droplet size is 1pL (picoliter) to 30pL. Therefore, even if the air flow is slightly turbulent, the flying direction of the droplets will change, resulting in a decrease in printing quality. In addition, the air-cooled air flow collides with the circuit substrate 2, so it is possible that the mist of the ink floating in the air adheres to the circuit substrate 2. If the mist of the ink adheres to the circuit substrate 2, depending on the components in the mist, it will have an adverse effect on the electrical structural elements on the circuit substrate 2, thereby becoming a cause of failure. The liquid-cooled control device 1, 1B will not cause such an adverse situation to occur, and is therefore suitable as a control device for an inkjet printing device. In particular, the control devices 1 and 1B of the present disclosure are liquid-cooled and have excellent maintainability. Therefore, when one or more inkjet heads mounted on the inkjet printing device fail, the inkjet heads can be easily replaced, and thus they are preferably used.

[0100] In addition, for a plurality of inkjet heads, when a one-to-one corresponding circuit substrate 2 is mounted on the control device 1, 1B, the ejection of each inkjet head can be controlled by using the same plurality of circuit substrates 2, so that the ejection characteristics are consistent between each inkjet head, thereby enabling high-quality inkjet printing. In addition, by separating the circuit substrate 2 from the inkjet head and connecting them with a flexible substrate, the heat generated by the circuit substrate 2 can be suppressed from being transferred to the inkjet head. Therefore, the influence on the inkjet ejection caused by heat can be avoided, the inkjet head can be easily replaced, and an inkjet printing device with excellent maintainability can be provided.

[0101] According to the present disclosure, it is possible to provide a control device and an inkjet printing device having good heat dissipation characteristics and maintainability.

[0102] Industrial Applicability

[0103] The present disclosure can be applied to a control device and an inkjet printing device.

[0104] Description of Reference Numerals

[0105] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G: control device; 2: circuit board; 3, 3B: heat transfer part; 4: low heat transfer part; 5, 5C, 5D, 5E, 5F, 5G: cooling part; 5C1, 5D1: first cooling part; 5C2, 5D2: second cooling part; 5D3: third cooling part; 5D4: fourth cooling part; 5D5: fifth cooling part; 7: concentrated heating part; 8, 8a, 8b: electrical structural element; 9: viscous body; 21, 22, 23, 24, 25: first, second, third, fourth, fifth circuit board; 31, 31B: first heat transfer part; 32, 32B: second heat transfer part; 33, 33B: third heat transfer part; 34, 34B: fourth heat transfer part Heat part; 35, 35B: fifth heat conducting part; 36, 36B: sixth heat conducting part; 37, 37B: seventh heat conducting part; 38, 38B: eighth heat conducting part; 39, 39B: ninth heat conducting part; 40, 40B: tenth heat conducting part; 51, 51E, 51F, 51G: refrigerant flow path; 51E1, 51F1, 51G1: first flow path; 51E2, 51F2, 51G2: second flow path; 51E3, 51F3: third flow path; 52E1, 52F1, 52G1, 52G3: inlet; 52E2, 52F2, 52G2, 52G4: outlet; 301, 301B, 302, 302B: contact surface; 400: screw; C: gap; R: refrigerant.

Claims

1. A control device comprising: a plurality of circuit substrates; a plurality of heat conducting parts connected to the plurality of circuit substrates; and at least one cooling unit is disposed on one end side of the plurality of circuit substrates in the width direction, and cools the plurality of circuit substrates via the plurality of heat conducting units, The plurality of circuit boards are arranged so as to be offset from each other in the width direction.

2. The control device according to claim 1, wherein: The plurality of circuit substrates and the plurality of heat conducting parts constitute a plurality of cooled parts. The plurality of cooled parts respectively include one circuit substrate among the plurality of circuit substrates, and one or more heat conducting parts among the plurality of heat conducting parts fixed to a single surface or two surfaces of the one circuit substrate, The plurality of cooled portions are configured to be attachable to and detachable from each other.

3. The control device according to claim 1, wherein: The control device further includes a low heat conduction portion arranged between one of the plurality of circuit substrates and one of the plurality of heat conduction portions.

4. The control device according to claim 1, wherein: The plurality of heat conducting parts and the at least one cooling part are connected by screws.

5. The control device according to claim 3, wherein: The low thermal conductivity portion is composed of a resin layer.

6. The control device according to claim 5, wherein: The resin layer is formed by insulating coating.

7. The control device according to claim 1, wherein: The at least one cooling section comprises a plurality of cooling sections, The plurality of heat transfer parts are arranged so as to abut against the plurality of cooling parts.

8. The control device according to claim 1, wherein: The plurality of heat conducting parts are connected to frame grounds of the plurality of circuit substrates.

9. The control device according to claim 1, wherein: The at least one cooling unit is connected to frame grounds of the plurality of circuit substrates.

10. The control device according to claim 1, wherein: The at least one cooling unit has a refrigerant flow path, The at least one cooling portion is arranged in contact with the plurality of heat conducting portions arranged in one direction. The plurality of heat conducting parts include a first heat dissipating part located at a first end in the one direction, and a second heat dissipating part located at a second end opposite to the first end in the one direction, The refrigerant flow path includes a first flow path through which the refrigerant flows in a direction from the first heat transfer portion toward the second heat transfer portion, and a second flow path through which the refrigerant flows in a direction from the second heat transfer portion toward the first heat transfer portion.

11. The control device according to claim 10, wherein: The downstream end of the first flow path is directly connected to the upstream end of the second flow path or is connected via a third flow path.

12. An inkjet printing device comprising: a plurality of inkjet heads; and Control device, The control device comprises: A plurality of circuit substrates, which are used to control at least one of the plurality of inkjet heads; a plurality of heat conducting parts connected to the plurality of circuit substrates; and at least one cooling unit is disposed on one end side of the plurality of circuit substrates in the width direction, and cools the plurality of circuit substrates via the plurality of heat conducting units, The plurality of circuit boards are arranged so as to be offset from each other in the width direction.

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