Liquid discharge head, liquid discharge unit, and apparatus for discharging liquid

Abstract

To provide a liquid discharge head that exhibits excellent heat dissipation for a heating element, can prevent liquid from entering a circuit board, and prevents a failure in the circuit board that occurs when the liquid enters the circuit board.SOLUTION: A liquid discharge head that discharges liquid from a plurality of nozzles comprises a circuit board, a heat conductive sheet, a metal frame member, a drive IC, and a flexible printed wiring board. The metal frame member is disposed below the heat conductive sheet. The flexible printed wiring board has the drive IC mounted thereon, and one end of the flexible printed wiring board is connected to the circuit board. The heat conductive sheet is disposed on the bottom surface of the circuit board and disposed so as to extend from the bottom surface to the side surfaces of the circuit board.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, a liquid ejection unit, and an apparatus for ejecting a liquid.

Background Art

[0002] In a liquid ejection head, one formed by joining a plurality of members is known, and it is necessary to prevent liquid from entering inside from the joining portion. Examples of the liquid include not only the liquid to be ejected but also a temperature control liquid for adjusting the temperature of the members inside the liquid ejection head.

[0003] In Patent Document 1, in order to suppress the intrusion of liquid inside from between the frame member and the cover member, it is disclosed that an adhesive as a sealing agent is used between the outer peripheral surface of the cover member and the inner peripheral surface of the rib.

Summary of the Invention

Problems to be Solved by the Invention

[0004] For the purpose of adjusting the temperature of the members inside the liquid ejection head, a temperature control tube through which a temperature control liquid flows may be arranged in the vicinity of the cover member. In this case, the space between the temperature control port through which the temperature control liquid flows in and out and the cover member becomes narrow, and it may be difficult to seal the entire circumference of the cover member with a sealing agent. When the temperature control liquid leaks because the cover member cannot be sealed with a sealing agent, the liquid may enter up to the mounting portion of the circuit board due to capillary action or the like. In this case, the terminals in the circuit board are short-circuited and the circuit board is damaged.

[0005] Also, when using a drive IC as in Patent Document 1, the drive IC may generate heat. When the heat generation becomes excessive, it affects the drive, so for example, a refrigerant may be used as the temperature control liquid to dissipate heat from a heat generating element such as a drive IC. However, as described above, a liquid such as a temperature control liquid may enter up to the mounting portion of the circuit board, and there is a possibility that the terminals in the circuit board are short-circuited and the circuit board is damaged.

[0006] Therefore, an object of the present invention is to provide a liquid ejection head that has good heat dissipation properties of a heating element, can prevent liquid from entering a circuit board, and can prevent the occurrence of circuit board failures caused by the liquid entering the circuit board.

Means for Solving the Problems

[0007] To solve the above problems, the liquid ejection head of the present invention is a liquid ejection head that ejects liquid from a plurality of nozzles, comprising a liquid ejection part, a circuit board, a heat conduction sheet, a metal frame member, a driving IC, and a printed wiring board, wherein the nozzles are provided in the liquid ejection part, the metal frame member is disposed on the liquid ejection part, the circuit board is disposed on the metal frame member, the driving IC is mounted on the printed wiring board, one end of the printed wiring board is connected to the circuit board, the heat conduction sheet is disposed between the metal frame member and the circuit board and on the bottom surface of the circuit board, and is disposed from the bottom surface to the side surface of the circuit board characterized in that.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head that has good heat dissipation properties of a heating element, can prevent liquid from entering a circuit board, and can prevent the occurrence of circuit board failures caused by the liquid entering the circuit board.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a liquid ejection head, a liquid ejection unit, and an apparatus for ejecting a liquid according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc., and is included in the scope of the present invention as long as the functions and effects of the present invention are achieved in any aspect.

[0011] The liquid ejection head of the present embodiment is a liquid ejection head that ejects liquid from a plurality of nozzles, It includes a liquid ejection unit, a circuit board, a heat conduction sheet, a metal frame member, a driving IC, and a printed wiring board. The nozzle is provided in the liquid ejection unit, the metal frame member is disposed on the liquid ejection unit, and the circuit board is disposed on the metal frame member. The driving IC is mounted on the printed wiring board, and one end of the printed wiring board is connected to the circuit board. The heat conduction sheet is disposed between the metal frame member and the circuit board and on the bottom surface of the circuit board, and is disposed from the bottom surface to the side surface of the circuit board. It is characterized by this.

[0012] The liquid ejection unit of the present invention is characterized by including the liquid ejection head of the present invention. The apparatus for ejecting a liquid of the present invention is characterized by including the liquid ejection head or the liquid ejection unit of the present invention. The apparatus for ejecting a liquid may be used as, for example, a liquid ejection apparatus, an image forming apparatus, a printing apparatus, a recording apparatus, an inkjet recording apparatus, etc.

[0013] First, the liquid ejection head of the comparative example will be described with reference to FIG. 10. FIG. 10 is a schematic cross-sectional view for explaining the liquid ejection head of the comparative example. In the illustrated example, a temperature control liquid is caused to flow in and out from a temperature control port 41, and the temperature control liquid is circulated through a temperature control tube 42 and a frame 45 to perform temperature adjustment. The arrows in the figure schematically show the flow of the temperature control liquid. The temperature control liquid may be, for example, a coolant. Further, an insulating film 44 is provided between a substrate 46 and the frame 45.

[0014] In the comparative example, as shown in the figure, since the space (L in the figure) between the temperature control port 41 and the cover member 43 is narrow, it is difficult to seal the entire circumference of the cover member 43 with, for example, a sealing material. Therefore, when liquid such as a temperature control liquid leaks to the upper part of the frame 45 near the temperature control port 41 that is not sealed with the sealing material, the liquid may enter the mounting portion of the substrate 46 due to capillary action or the like. As a result, problems such as a short circuit between terminals in the substrate 46 and damage to the substrate 46 occur. Further, since the intrusion of the liquid can also occur on the side surface or the upper surface side of the substrate 46, countermeasures considering these are required.

[0015] In this embodiment, it is possible to prevent the liquid adhering to the upper surface portion or the like of the frame from entering the substrate and suppress the occurrence of substrate failure. In this embodiment, in order to prevent the liquid adhering to the upper surface portion or the like of the frame from entering the substrate, for example, the insulating film 44 of the comparative example is changed to a heat transfer sheet having heat conductivity, and in addition to the arrangement of the members, the arrangement, shape, etc. of the heat transfer sheet are appropriately changed.

[0016] The liquid ejection head of this embodiment includes a liquid ejection portion, a circuit board, a heat conduction sheet, a frame member, a drive IC, and a printed wiring board. In this embodiment, a nozzle is provided in the liquid ejection portion, a frame member is disposed on the liquid ejection portion, and a circuit board is disposed on the frame member. Further, a drive IC is mounted on the printed wiring board, and one end of the printed wiring board is connected to the circuit board.

[0017] The circuit board may be simply referred to as a substrate. The drive IC may be referred to as a DRV IC, and may also be referred to as a driver IC in other cases.

[0018] FIG. 1 is a schematic cross-sectional view for explaining an example of the heat conduction sheet. The heat conduction sheet 10 of this example has a base material 11 and an adhesive layer 12 provided on the base material 11. By doing so, the adhesiveness of the heat conduction sheet 10 is improved, and the disengagement of the members can be reduced. The adhesive layer may also be referred to as an adhesive or the like.

[0019] In the illustrated example, the adhesive layer 12 is provided on one side of the base material 11, but the present invention is not limited thereto, and the adhesive layer 12 may be provided on both sides of the base material 11. This embodiment is not limited to the case where the heat conduction sheet 10 has the adhesive layer 12, and an adhesive or the like may be used without the adhesive layer 12.

[0020] The outer dimensions of the heat conduction sheet can be appropriately selected. In this embodiment, the heat conduction sheet is disposed on the bottom surface of the circuit board and extends from the bottom surface of the circuit board to the side surface. To achieve this, when the heat conduction sheet is not bent, the outer dimensions of the heat conduction sheet are made larger than the outer dimensions of the substrate. When the heat conduction sheet 10 has the base material 11 and the adhesive layer 12, the sizes of the base material 11 and the adhesive layer 12 may be different. For example, the area of the adhesive layer 12 may be equivalent to the area of the circuit board 13.

[0021] The base material 11 is not particularly limited, and for example, a non-permeable and flexible heat conduction member is used. Examples of the material of the base material 11 include glass cloth base epoxy resin laminates. Commercially available products of glass cloth base epoxy resin laminates can be used. The material of the adhesive layer 12 is not particularly limited, and known materials can be used.

[0022] The heat conduction sheet has heat conductivity. It is preferably insulating. By having insulating properties, the occurrence of substrate failures due to short circuits can be prevented. In order for the heat conduction sheet to have insulating properties, for example, the numerical value of the insulation resistance is preferably 20 MΩ or more. The numerical value of the insulation resistance is measured, for example, by bringing terminals into contact with two different points on the sheet using an insulation resistance meter.

[0023] The thickness of the heat conduction sheet 10 can be appropriately selected. By being somewhat thin, the foldability can be improved and the expansion in the height direction can be suppressed. The thickness of the heat conduction sheet is preferably 0.1 mm or more and 1.0 mm or less. In this case, the bendability is improved, the adhesion from the bottom surface to the side surface of the substrate is improved, and the effect of preventing the intrusion of liquid can be enhanced. More preferably, the thickness of the heat conduction sheet is 0.5 mm or more and 1.0 mm or less. In this case, the bendability is further improved, the adhesion from the bottom surface to the side surface of the substrate is further improved, and the effect of preventing the intrusion of liquid can be further enhanced. In addition, since the thickness of the heat conduction sheet is 1.0 mm or less, the thermal resistance in the thickness direction can be kept low, so that the heat dissipation effect is improved.

[0024] FIG. 2 is a schematic plan view for explaining an example of the heat conduction sheet 10, and is an example when viewed from above. The heat conduction sheet 10 in this example is provided with an opening 20 for passing a flexible printed wiring board (sometimes also referred to as FPC). By passing the FPC through the opening 20, the FPC connected to the substrate can be brought into contact with the frame. The number, size, and arrangement of the openings 20 are not limited to those shown, and can be changed as appropriate.

[0025] FIG. 3 is a schematic cross-sectional view showing an example when the heat conduction sheet 10 is arranged. The liquid discharge portion 16 has a nozzle surface 16a, and nozzles are formed on the nozzle surface 16a. Here, the illustration of the nozzles is omitted. Liquid is discharged from the nozzles. The discharge direction of the liquid is schematically shown by the white arrow in the figure.

[0026] A frame member 15 is arranged on the liquid discharge portion 16. A circuit board 13 is arranged on the frame member 15. As shown in the figure, the heat conduction sheet 10 is arranged between the circuit board 13 and the frame member 15. In this example, the adhesive layer 12 of the heat conduction sheet 10 is on the side of the frame member 15, and the base material 11 is on the side of the circuit board 13. The reference numerals 10a and 10b are attached to explain that the heat conduction sheet 10 is bent.

[0027] An example of attaching the heat conduction sheet 10 will be described. The heat conduction sheet 10 is disposed between the circuit board 13 and the frame member 15 such that the adhesive layer 12 of the heat conduction sheet 10 faces the frame member 15 side. The end portion of the heat conduction sheet 10 protruding beyond the outer shape of the circuit board 13 is bent in the height direction of the circuit board 13 (bending portion 10a). By bending in this way, the heat conduction sheet 10 is disposed up to a position higher than the height dimension of the circuit board 13, and the heat conduction sheet 10 is further bent at the bending portion 10b.

[0028] In this example, by bending the heat conduction sheet 10 at the bending portion 10b, the adhesive layer 12 contacts the ink tank 14, so that it can be fixed to the tank 14 using the adhesive layer 12. When the heat conduction sheet 10 does not have the adhesive layer 12, it can be fixed using an adhesive or the like. The fixing to the ink tank 14 may be partial.

[0029] The heat conduction sheet 10 is disposed between the frame member 15 and the circuit board 13 and on the bottom surface of the circuit board 13, and is disposed from the bottom surface to the side surface of the circuit board 13. By doing so, even when liquid adheres to the upper surface of the end portion of the frame member 15, the heat conduction sheet 10 can prevent the liquid from entering the circuit board 13 due to capillary action or the like. Further, since the heat conduction sheet 10 is provided on the side surface of the circuit board 13, the heat conduction sheet 10 can prevent the liquid from entering the circuit board 13 due to capillary action or the like from the side surface side. Thereby, it is possible to prevent the occurrence of failures of the circuit board 13 caused by the liquid entering the circuit board 13.

[0030] As in the example shown in FIG. 3, it is preferable that the heat conduction sheet 10 is disposed from the bottom surface of the circuit board 13 through the side surface to at least a part of the upper portion of the circuit board 13. By doing so, when the liquid ejection head is tilted or turned upside down, it is possible to prevent liquid from entering the upper part of the circuit board 13, and further prevent the occurrence of failures due to liquid intrusion. If the liquid intrusion path seems to be limited, the heat conduction sheet 10 does not need to be arranged up to the upper surface portion of the circuit board 13, and it may be up to the side surface portion of the circuit board 13.

[0031] One or more components are provided on the upper part of the circuit board 13. The heat conduction sheet 10 is preferably arranged from the bottom surface of the circuit board 13 through the side surface portion to at least a part of the upper part of the circuit board 13 and in close contact with one or more components. Since the heat conduction sheet is in close contact not only with the circuit board 13 but also with the components on the circuit board 13, when the liquid ejection head is tilted or turned upside down, it is possible to prevent liquid from entering between the circuit board 13 and the components on the circuit board 13. Also, the occurrence of failures due to liquid intrusion can be further prevented.

[0032] The components provided on the circuit board 13 are not particularly limited, and examples include an ink tank and the like. When the component provided on the circuit board 13 is an ink tank, for example, an arrangement example as shown in FIG. 3 can be adopted. The number of components provided on the circuit board 13 is not particularly limited, and it may be one or a plurality. The method for the heat conduction sheet to be in close contact with the components on the circuit board 13 is not particularly limited, and examples include a method of attaching an adhesive or a sticky agent to the components.

[0033] A supplementary explanation of an example of attaching the heat conduction sheet 10 will be given with reference to FIG. 4. FIG. 4 is a schematic plan view for schematically explaining the outer shapes of the circuit board 13 and the heat conduction sheet 10. (A) is an example in which the outer shape of the heat conduction sheet 10 is larger than that of the circuit board 13 in the short side portion of the circuit board 13. The example shown in (A) can also be said to be an example in which the outer shape of the heat conduction sheet 10 is larger than that of the circuit board 13 in the longitudinal direction of the circuit board 13. For example, the heat conduction sheet 10 is bent at the bending portion 10a and the heat conduction sheet 10 is disposed on the side surface portion of the circuit board 13, and the heat conduction sheet 10 is bent at the bending portion 10b and the heat conduction sheet 10 is disposed on a part of the upper portion of the circuit board 13.

[0034] (B) is an example in which the outer shape of the heat conduction sheet 10 is larger than that of the circuit board 13 in both the short side and the long side portions of the circuit board 13. The example shown in (B) can also be said to be an example in which the outer shape of the heat conduction sheet 10 is larger than that of the circuit board 13 in both the longitudinal direction and the short side direction of the circuit board 13. For example, the heat conduction sheet 10 is bent at the bending portion 10a and the heat conduction sheet 10 is disposed on the side surface portion in the short side of the circuit board 13, the heat conduction sheet 10 is bent at the bending portion 10c and the heat conduction sheet 10 is disposed on the side surface portion in the long side of the circuit board 13, and the heat conduction sheet 10 is bent at the bending portion 10b and the heat conduction sheet 10 is disposed on a part of the upper portion of the circuit board 13. In the example shown in (B), the extra portion of the heat conduction sheet 10 may be cut.

[0035] In both (A) and (B) of FIG. 4, the heat conduction sheet 10 can be disposed as shown in FIG. 3(A). As in (A), the heat conduction sheet 10 may be disposed on the short side surface portion of the circuit board 13 and not on the long side surface portion. Even in this case, the effect of preventing liquid from entering can be obtained. In addition to this, the heat conduction sheet 10 may be disposed on the long side surface portion of the circuit board 13 and not on the short side surface portion. Even in this case, the effect of preventing liquid from entering can be obtained. On the other hand, as in (B), the heat conduction sheet 10 may be disposed on both the short side and the long side surface portions of the circuit board 13. In this case, the effect of preventing liquid from entering is improved. (A) is easier to manufacture than (B).

[0036] When the heat conduction sheet 10 has the base material 11 and the base material 11 is a non - permeable base material, it becomes more difficult for the liquid to penetrate, so the effect of liquid penetration is improved. Further, when the heat conduction sheet 10 has the adhesive layer 12, the adhesion with the frame member 15 and the ink tank 14 is improved, and it becomes more difficult for the liquid to penetrate, so the effect of liquid penetration is improved.

[0037] FIG. 5 is a schematic side view showing an example of the state before the heat conduction sheet 10 is attached to the frame member 15. FIG. 5 may be a schematic cross - sectional view. (A) is a view looking at the longitudinal direction, and (B) and (C) are views looking at the short - hand direction. The white arrow in the figure schematically shows the attachment direction of the frame member 15.

[0038] As also described in FIG. 4, as shown in FIG. 5(B), the heat conduction sheet 10 may be disposed on the short - hand side surface portion of the circuit board 13, and it is not necessary to dispose the heat conduction sheet 10 on the long - hand side surface portion. Further, as shown in FIG. 5(C), the heat conduction sheet 10 may be disposed on both the short - hand and long - hand side surface portions of the circuit board 13.

[0039] As the side surface portion of the circuit board 13 where the heat conduction sheet 10 is disposed, even if it is a part of the side surface portion, the effect of preventing the intrusion of the liquid can be obtained, but it is preferably the entire side surface portion of the circuit board 13. In FIGS. 3 and 5, it is done in this way. Unless otherwise specified, when referring to the side surface portion of the circuit board 13, it means the entire side surface portion. FIG. 5(B) shows that the heat conduction sheet 10 is disposed on the entire short - hand side surface portion of the circuit board 13, and FIG. 5(C) shows that the heat conduction sheet 10 is disposed on the entire short - hand and long - hand side surface portions of the circuit board 13.

[0040] Even when the side surface portion of the circuit board 13 where the heat conduction sheet 10 is disposed is a part of the side surface portion of the circuit board 13, the heat conduction sheet 10 is disposed on the bottom surface portion and a part of the side surface portion of the circuit board 13. Therefore, it is possible to prevent the liquid adhering on the frame member 15 from penetrating into the circuit board 13 side from the vicinity of the bottom surface portion of the circuit board 13.

[0041] Further, as the bottom surface portion of the circuit board 13 on which the heat conduction sheet 10 is disposed, it is preferable that it is the entire surface of the bottom surface portion of the circuit board 13, and this is the case in the present embodiment. As the bottom surface portion of the circuit board 13 on which the heat conduction sheet 10 is disposed, it may be a part of the bottom surface portion of the circuit board 13. In that case, at least the heat conduction sheet 10 is disposed on the bottom surface portion in the vicinity of the side surface portion of the circuit board 13.

[0042] FIG. 6(A) is a schematic plan view when the frame member 15 in FIG. 5 is viewed from above. FIG. 6(B) is a schematic cross-sectional view of the frame member 15 in FIG. 5. As shown in FIG. 6, an opening 21 is provided in the frame member 15.

[0043] A drive IC 18 is mounted on the FPC 17. The term "mounted" may also be referred to as simply the drive IC 18 being provided on the FPC 17, the drive IC 18 being attached to the FPC, etc.

[0044] As shown in FIG. 2, an opening 20 is provided in the heat conduction sheet 10 of this example, and one end of the FPC 17 (flexible printed wiring board) is connected to the circuit board 13 (circuit board) through the opening 20. In FIG. 5, the illustration of the opening 20 is omitted.

[0045] Referring to FIGS. 5 and 6 for explanation, the heat conduction sheet 10 and the frame member 15 are attached by passing the FPC 17 through the opening 21 of the frame member 15. Thereby, the FPC 17 is installed in the frame member 15 in a form inserted into the opening 21 in the frame member 15.

[0046] In this example, as shown in FIGS. 2, 5, and 6, two openings are provided, but the present embodiment is not limited to this, and one opening may be provided, or more than two openings may be provided.

[0047] The FPC 17 (flexible printed circuit board) is an example of a printed circuit board. One end of the FPC 17 is connected to the circuit board 13, and the other end of the FPC 17 is connected to, for example, a piezoelectric element or the like. The printed circuit board is not limited to the flexible printed circuit board, but in the case of the flexible printed circuit board, since the shape of the printed circuit board can be changed, it becomes easier to adjust the position of the printed circuit board within the frame member 15 or the like.

[0048] FIG. 7 is a schematic cross-sectional view for explaining an example in the example shown in FIG. 5 when the FPC 17 is disposed in the opening 21 of the frame member 15. The drive IC 18 is mounted on the FPC 17. The wiring pattern can be appropriately selected, and one end of the FPC 17 is connected to the component surface (front surface) of the circuit board 13. The drive IC 18 is disposed on one surface of the FPC 17 via, for example, a copper through hole.

[0049] Reference numeral 28 schematically indicates the connection destination of the other end of the FPC 17. Although not particularly limited, examples of the connection destination of the other end of the FPC 17 include a piezoelectric element.

[0050] The heat of the drive IC 18 is transmitted to the frame member 15 via the FPC 17, the circuit board 13, and the heat conduction sheet 10. In addition to the heat conduction sheet 10 for conducting heat being provided between the circuit board 13 and the frame member 15, in the present embodiment, since the frame member 15 is a metal member, the heat dissipation of heat generating elements such as the drive IC 18 can be improved.

[0051] The frame member 15 (metal frame member) is not particularly limited and can be appropriately selected. The metal used for the frame member 15 is not particularly limited, and examples include SUS303, SUS304, and the like.

[0052] The example shown in FIG. 3 is an example when the ink tank 14 is provided. The ink tank 14 supplies a liquid (e.g., ink) to the liquid flow path of the liquid ejection unit 16. The supplied liquid flows through the liquid flow path, for example, and is supplied to the liquid chamber, and is ejected from the nozzles provided on the nozzle surface 16a of the liquid ejection unit 16 by a piezoelectric element (which may be referred to as a piezo, etc.).

[0053] In FIG. 3, in the central part of the drawing plane, the ink tank 14 and the circuit board 13 appear to be in contact, but the ink tank 14 may or may not be in contact with the circuit board 13.

[0054] An example of the configuration when having the ink tank 14 will be described again. It includes the ink tank 14 arranged on the circuit board 13. The heat conduction sheet 10 is arranged from the bottom surface of the circuit board 13 through the side surface portion to at least a part of the upper portion of the circuit board 13. The ink tank 14 and the circuit board 13 are arranged via the heat conduction sheet 10.

[0055] The heat conduction sheet 10 fixes the ink tank 14 and at the same time will be pressed by the shape of the ink tank 14. Therefore, the ink tank 14 and the circuit board 13 can be brought into close contact without a gap. Also, by arranging the ink tank 14 as shown, the circuit board 13 and the frame member 15 can be brought into close contact without a gap. Further, since the contact thermal resistance of the heat conduction sheet 10 is reduced by being pressed, the heat conductivity to the frame member 15 is improved.

[0056] An example of the configuration when having the ink tank 14 and an example of the configuration when the heat conduction sheet 10 has the adhesive layer 12 will be described again. It includes an ink tank 14 disposed on the circuit board 13. The heat conduction sheet 10 is disposed from the bottom surface of the circuit board 13 through the side surface to at least a part of the upper portion of the circuit board 13. The ink tank 14 and the circuit board 13 are disposed via the heat conduction sheet 10. For the heat conduction sheet 10 disposed between the ink tank 14 and the circuit board 13, the adhesive layer 12 contacts the ink tank 14. For the heat conduction sheet 10 disposed between the frame member 15 and the circuit board 13, the adhesive layer 12 contacts the frame member 15.

[0057] By doing so, the ink tank 14 and the circuit board 13 can be closely adhered without a gap, and the circuit board 13 and the frame member 15 can be closely adhered without a gap. Also, since the contact thermal resistance of the heat conduction sheet 10 is reduced when it is pressed, the heat conductivity to the frame member 15 is improved. Furthermore, by making the adhesive layer 12 as described above, the adhesion of the ink tank 14, the circuit board 13, and the frame member 15 is improved.

[0058] In this embodiment, a flow path through which a temperature control liquid flows may be provided in the frame member 15. The flow path through which the temperature control liquid flows may be referred to as a temperature control liquid flow path or the like. Examples of the temperature control liquid include a refrigerant liquid.

[0059] Preferably, a flow path through which the refrigerant liquid flows is provided inside the frame member 15. By providing a flow path through which the refrigerant liquid flows, the frame member 15 can be cooled. As a result, since the heat from the driving IC 18 is transmitted to the frame member 15 via the FPC 17, the circuit board 13, and the heat conduction sheet 10, the heat dissipation effect of the driving IC 18 can be enhanced. The flow path through which the refrigerant liquid flows may be referred to as a refrigerant liquid flow path, a heat dissipation path, or the like.

[0060] FIG. 8(A) is a schematic cross-sectional view of the frame member 15 when a refrigerant liquid flow path is provided, and is a view showing an example when the frame member 15 is viewed from above. FIG. 8(B) is a schematic cross-sectional view of the frame member 15, and is a view showing an example when the frame member 15 is viewed from the side.

[0061] As shown in the figure, a refrigerant liquid flow path 22 is provided in the frame member 15 of this example. The refrigerant liquid flow path 22 is formed inside the frame member 15 so that the refrigerant liquid can circulate through the refrigerant liquid flow path 22.

[0062] The refrigerant liquid is not particularly limited, and known ones can be used. The method of circulating the refrigerant liquid is not particularly limited, and known circulation means can be used. For example, the temperature control port 41, the temperature control tube 42, etc. shown in FIG. 10 may be used. The shape of the refrigerant liquid flow path 22 is not particularly limited and can be appropriately selected. For example, it may be a single path with one end as the inlet and the other end as the outlet. Also, there may be a plurality of inlets and outlets.

[0063] FIG. 9 is a schematic cross-sectional view for explaining an example when the FPC 17 is arranged in the opening 21 of the frame member 15 in the example shown in FIG. 8. Similar to FIG. 7, the driving IC 18 is mounted on the FPC 17, and one end of the FPC 17 is connected to the component surface (front surface) of the circuit board 13. The driving IC 18 is arranged on one surface of the FPC 17 via, for example, a copper through hole.

[0064] The heat of the driving IC 18 is transmitted to the frame member 15 via the FPC 17, the circuit board 13, and the heat conduction sheet 10. Inside the frame member 15 which is a metal member, a refrigerant liquid flow path 22 is provided, and the frame member 15 is cooled. Therefore, the heat dissipation effect of heat generating elements such as the driving IC 18 can be further improved.

[0065] The comparative example shown in FIG. 10 will be described again, and the excellent effects obtained in the examples included in the present invention will be described again. Although illustration is omitted in the comparative example shown in FIG. 10, a driving IC (also referred to as a driver IC, DRV IC, etc.) that selects and drives necessary pulses is mounted on a flexible printed wiring board (sometimes also referred to as an FPC) in order to apply driving pulses to the piezo. Further, the FPC is disposed in the space within the frame member 15, and one end of the FPC is connected to the circuit board 13. The driving IC may have an analog switch or the like, and generates heat by supplying current to the piezo, discharging current from the piezo, and the like. In the comparative example, although the frame member 15 is cooled by a temperature control flow path, since the heat dissipation path of the driving IC is not directly connected to the frame member 15, there is a problem that the cooling efficiency of the driving IC is low.

[0066] In the example included in the present invention, the driving IC 18 is mounted on the FPC 17, and the wiring pattern of the FPC 17 is connected to the component surface (front surface) of the circuit board 13. The wiring pattern is disposed on the back surface of the circuit board 13 via, for example, a copper through hole. The heat of the driving IC 18 is transmitted from the FPC 17 to the wiring pattern on the back surface of the circuit board 13. Since the heat conduction sheet 10 is disposed on the back surface of the circuit board 13, the heat of the driving IC 18 is transmitted to the frame member 15 cooled by the temperature control liquid via the heat conduction sheet 10. In this example, the heat of the driving IC transmitted to the circuit board 13 is transmitted to the frame member 15 cooled by the refrigerant liquid via the heat conduction sheet 10. Thereby, the heat dissipation effect of the driving IC 18 can be enhanced.

[0067] In the liquid ejection head of the present embodiment, the temperature control tube 42, the temperature control port 41, and the cover member 43 shown in FIG. 10 may be used. Even in this case, it is not necessary to seal the periphery of the cover member 43 with a sealing agent to prevent the intrusion of liquid. In the present embodiment, even when temperature control as shown in FIG. 10 is performed, it is possible to prevent the intrusion of liquid into the circuit board 13 without using a sealing agent, and to prevent a failure of the circuit board 13 caused by the intrusion of liquid into the circuit board 13.

[0068] Next, an example of an apparatus for discharging a liquid according to the present invention will be described with reference to FIGS. 11 and 12. FIG. 11 is a plan explanatory view of a main part of the apparatus, and FIG. 12 is a side explanatory view of the main part of the apparatus.

[0069] This apparatus is a serial type apparatus. By the main scanning movement mechanism 493, the carriage 403 reciprocates in the main scanning direction. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 is bridged between the left and right side plates 491A and 491B and holds the carriage 403 movably. Then, by the main scanning motor 405, the carriage 403 is reciprocated in the main scanning direction via the timing belt 408 bridged between the drive pulley 406 and the driven pulley 407.

[0070] This carriage 403 is equipped with a liquid discharge unit 440 in which a liquid discharge head 404 and a head tank 441 according to the present invention are integrated. The liquid discharge head 404 of the liquid discharge unit 440 discharges liquids of respective colors such as yellow (Y), cyan (C), magenta (M), and black (K), for example. Further, the liquid discharge head 404 arranges a nozzle row composed of a plurality of nozzles 11 in the sub-scanning direction orthogonal to the main scanning direction and is mounted with the discharge direction facing downward.

[0071] By a supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404, the liquid stored in the liquid cartridge 450 is supplied to the head tank 441.

[0072] The supply mechanism 494 is composed of a cartridge holder 451 which is a filling part for mounting the liquid cartridge 450, a tube 456, a liquid feed unit 452 including a liquid feed pump, and the like. The liquid cartridge 450 is detachably mounted on the cartridge holder 451. The liquid is fed from the liquid cartridge 450 to the head tank 441 by the liquid feed unit 452 via the tube 456.

[0073] This device is equipped with a conveyance mechanism 495 for conveying the paper 410. The conveyance mechanism 495 includes a conveyance belt 412 which is a conveyance means, and a sub-scanning motor 416 for driving the conveyance belt 412.

[0074] The conveyance belt 412 adsorbs the paper 410 and conveys it to a position facing the liquid ejection head 404. This conveyance belt 412 is an endless belt and is stretched between a conveyance roller 413 and a tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction, etc.

[0075] Then, the conveyance belt 412 makes a circular movement in the sub-scanning direction by the conveyance roller 413 being rotationally driven via a timing belt 417 and a timing pulley 418 by the sub-scanning motor 416.

[0076] Furthermore, on one side of the carriage 403 in the main scanning direction, a maintenance and recovery mechanism 420 for maintaining and recovering the liquid ejection head 404 is arranged on the side of the conveyance belt 412.

[0077] The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 for capping the nozzle surface (the surface where the nozzles 11 are formed) of the liquid ejection head 404, a wiper member 422 for wiping the nozzle surface, etc.

[0078] The main scanning movement mechanism 493, the supply mechanism 494, the maintenance and recovery mechanism 420, and the conveyance mechanism 495 are attached to a housing including side plates 491A, 491B and a back plate 491C.

[0079] In this device configured in this way, the paper 410 is fed onto the conveyance belt 412 and adsorbed, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 412.

[0080] Therefore, while moving the carriage 403 in the main scanning direction, the liquid ejection head 404 is driven according to the image signal, thereby ejecting liquid onto the stationary paper 410 to form an image.

[0081] Thus, since this apparatus includes the liquid ejection head according to the present invention, a high-quality image can be stably formed.

[0082] Next, another example of the liquid ejection unit according to the present invention will be described with reference to FIG. 13. FIG. 13 is a plan explanatory view of the main part of the unit.

[0083] This liquid ejection unit includes a housing portion composed of side plates 491A and 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 404 among the members constituting the apparatus that ejects the liquid.

[0084] Note that a liquid ejection unit can also be configured by further attaching at least one of the above-described maintenance and recovery mechanism 420 and supply mechanism 494 to, for example, the side plate 491B of this liquid ejection unit.

[0085] Next, still another example of the liquid ejection unit according to the present invention will be described with reference to FIG. 14. FIG. 14 is a front explanatory view of the unit.

[0086] This liquid ejection unit includes a liquid ejection head 404 to which a flow path component 444 is attached and a tube 456 connected to the flow path component 444.

[0087] Note that the flow path component 444 is disposed inside a cover 442. Instead of the flow path component 444, a head tank 441 can also be included. Further, a connector 443 for making an electrical connection with the liquid ejection head 404 is provided above the flow path component 444.

[0088] In the present application, the "apparatus that ejects liquid" is an apparatus that includes a liquid ejection head or a liquid ejection unit and drives the liquid ejection head to eject liquid. The apparatus that ejects liquid includes not only an apparatus that can eject liquid onto an object to which the liquid can adhere but also an apparatus that ejects liquid into the air or liquid.

[0089] This "device for discharging a liquid" can also include means related to the feeding, conveying, and paper discharging of objects to which the liquid can adhere, as well as other pre-treatment devices, post-treatment devices, and the like.

[0090] For example, as the "device for discharging a liquid", there are an image forming device that discharges ink to form an image on a sheet, and a three-dimensional modeling device (3D modeling device) that discharges a modeling liquid onto a powder layer formed by layering powders in order to model a three-dimensional object (3D object).

[0091] Also, the "device for discharging a liquid" is not limited to those in which a significant image such as characters or figures is visualized by the discharged liquid. For example, those that form a pattern having no meaning by itself, and those that model a three-dimensional image are also included.

[0092] The above-mentioned "objects to which the liquid can adhere" means objects to which the liquid can adhere at least temporarily, such as those that adhere and adhere firmly, those that adhere and penetrate, etc. Specific examples include recording media such as paper, recording paper, recording sheets, films, and cloth, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and media such as test cells, and all objects to which the liquid adheres are included unless otherwise particularly limited.

[0093] The material of the above-mentioned "objects to which the liquid can adhere" may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and floor materials, textile for clothing, etc., as long as the liquid can adhere even temporarily.

[0094] Also, the "liquid" includes ink, treatment liquid, DNA sample, resist, pattern material, binder, modeling liquid, or solutions and dispersions containing amino acids, proteins, calcium, etc.

[0095] In addition, the "device for discharging a liquid" includes, but is not limited to, a device in which a liquid discharge head and an object to which the liquid can adhere move relative to each other. Specific examples include a serial type device that moves the liquid discharge head and a line type device that does not move the liquid discharge head.

[0096] In addition, other examples of the "device for discharging a liquid" include a processing liquid application device that discharges a processing liquid onto a sheet for the purpose of modifying the surface of the sheet, and an injection granulation device that injects a composition liquid in which raw materials are dispersed in a solution through a nozzle to granulate fine particles of the raw materials.

[0097] The "liquid discharge unit" is an integrated unit of functional components and mechanisms with a liquid discharge head, and is an assembly of components related to liquid discharge. For example, the "liquid discharge unit" includes at least one of the configurations of a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism combined with the liquid discharge head.

[0098] Here, the integration includes, for example, those in which the liquid discharge head and functional components and mechanisms are fixed to each other by fastening, adhesion, engagement, etc., and those in which one is held movably with respect to the other. Also, the liquid discharge head and functional components and mechanisms may be configured to be detachable from each other.

[0099] For example, as a liquid discharge unit, there is one in which a liquid discharge head and a head tank are integrated, such as the liquid discharge unit 440 shown in FIG. 12. Also, there is one in which a liquid discharge head and a head tank are integrated by being connected to each other with a tube or the like. Here, a unit including a filter can also be added between the head tank and the liquid discharge head of these liquid discharge units.

[0100] In addition, as a liquid discharge unit, there is one in which a liquid discharge head and a carriage are integrated.

[0101] In addition, as a liquid discharge unit, there is one in which a liquid discharge head is movably held by a guide member that forms part of a scanning movement mechanism, and the liquid discharge head and the scanning movement mechanism are integrated. Also, as shown in FIG. 13, as a liquid discharge unit, there is one in which a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

[0102] In addition, as a liquid discharge unit, there is one in which a cap member that is part of a maintenance and recovery mechanism is fixed to a carriage to which a liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance and recovery mechanism are integrated.

[0103] In addition, as a liquid discharge unit, as shown in FIG. 14, there is one in which a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated.

[0104] The main scanning movement mechanism shall include a single guide member. Also, the supply mechanism shall include a single tube and a single loading unit.

[0105] In addition, the "liquid discharge head" is not limited to the pressure generating means used. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, an electrostatic actuator composed of a diaphragm and a counter electrode, etc. may also be used.

[0106] Also, in the terms of this application, image formation, recording, printing, imprinting, printing, shaping, etc. are all synonymous.

[0107] Aspects of the present invention are as follows, for example. <1> A liquid discharge head that discharges liquid from a plurality of nozzles, comprising a liquid discharge portion, a circuit board, a heat conduction sheet, a metal frame member, a driving IC, and a printed wiring board. The nozzle is provided in the liquid ejection unit, the metal frame member is disposed on the liquid ejection unit, and the circuit board is disposed on the metal frame member. The drive IC is mounted on the printed wiring board, and one end of the printed wiring board is connected to the circuit board. The heat conductive sheet is disposed between the metal frame member and the circuit board and on the bottom surface of the circuit board, and is disposed from the bottom surface to the side surface of the circuit board. A liquid ejection head characterized by the above. <2> The heat conductive sheet has a base material and an adhesive layer provided on the base material. The liquid ejection head according to <1>, characterized by the above. <3> The heat conductive sheet disposed between the metal frame member and the circuit board has the adhesive layer in contact with the metal frame member. The liquid ejection head according to <2>, characterized by the above. <4> An ink tank is provided on the circuit board. The heat conductive sheet is disposed from the bottom surface to at least a part of the upper portion of the circuit board through the side surface of the circuit board. The ink tank and the circuit board are disposed via the heat conductive sheet. The heat conductive sheet disposed between the ink tank and the circuit board has the adhesive layer in contact with the ink tank. The heat conductive sheet disposed between the metal frame member and the circuit board has the adhesive layer in contact with the metal frame member. The liquid ejection head according to <2>, characterized by the above. <5> An ink tank is provided on the circuit board. The heat conductive sheet is disposed from the bottom surface to at least a part of the upper portion of the circuit board through the side surface of the circuit board. The ink tank and the circuit board are disposed via the heat conductive sheet. The liquid ejection head according to any one of <1> to <3>, characterized in that... <6> The heat conduction sheet is disposed from the bottom surface of the circuit board through the side surface portion to at least a part of the upper portion of the circuit board. The liquid ejection head according to any one of <1> to <5>, characterized in that... <7> The thickness of the heat conduction sheet is 0.1 mm or more and 1.0 mm or less. The liquid ejection head according to any one of <1> to <6>, characterized in that... <8> The thickness of the heat conduction sheet is 0.5 mm or more and 1.0 mm or less. The liquid ejection head according to any one of <1> to <6>, characterized in that... <9> A flow path through which a refrigerant liquid flows is provided inside the metal frame member. The liquid ejection head according to any one of <1> to <8>, characterized in that... <10> Comprises the liquid ejection head according to any one of <1> to <9>. The liquid ejection unit, characterized in that... <11> At least one of a head tank for storing the liquid to be supplied to the liquid ejection head, a carriage on which the liquid ejection head is mounted, a supply mechanism for supplying the liquid to the liquid ejection head, a maintenance and recovery mechanism for performing maintenance and recovery of the liquid ejection head, and a main scanning movement mechanism for moving the liquid ejection head in the main scanning direction is integrated with the liquid ejection head. The liquid ejection unit according to <10>, characterized in that... <12> Comprises the liquid ejection head according to any one of <1> to <9>, or the liquid ejection unit according to <10> or <11>. The apparatus for ejecting a liquid, characterized in that...

Explanation of Reference Numerals

[0108] 10 Heat conduction sheet 11 Substrate 12 Adhesive layer 13 Circuit board 14 Ink tank 15 Frame member 16 Liquid ejection part 17 FPC 18 Driving IC 20, 21 Opening 22 Refrigerant liquid flow path 41 Temperature control port 42 Temperature control tube 43 Cover member 44 Insulating film

Prior art documents

Patent documents

[0109]

Patent Document 1

Claims

1. A liquid ejection head that ejects liquid from a plurality of nozzles, comprising a liquid ejection section, a circuit board, a heat conduction sheet, a metal frame member, a drive IC, and a printed wiring board, wherein the nozzles are provided in the liquid ejection section, the metal frame member is disposed on the liquid ejection section, the circuit board is disposed on the metal frame member, the drive IC is mounted on the printed wiring board, one end of the printed wiring board is connected to the circuit board, the heat conduction sheet is disposed between the metal frame member and the circuit board and on the bottom surface of the circuit board, and is disposed from the bottom surface to the side surface of the circuit board, characterized in that it is a liquid ejection head.

2. The heat conduction sheet has a base material and an adhesive layer provided on the base material. The liquid ejection head according to claim 1, characterized in that.

3. For the heat conduction sheet disposed between the metal frame member and the circuit board, the adhesive layer contacts the metal frame member. The liquid ejection head according to claim 2, characterized in that.

4. comprising an ink tank disposed on the circuit board, the heat conduction sheet is disposed from the bottom surface to at least a part of the upper portion of the circuit board through the side surface of the circuit board, the ink tank and the circuit board are disposed via the heat conduction sheet, for the heat conduction sheet disposed between the ink tank and the circuit board, the adhesive layer contacts the ink tank, for the heat conduction sheet disposed between the metal frame member and the circuit board, the adhesive layer contacts the metal frame member. The liquid ejection head according to claim 2, characterized in that.

5. comprising an ink tank disposed on the circuit board, the heat conduction sheet is disposed from the bottom surface of the circuit board through the side surface portion to at least a part of the upper portion of the circuit board, the ink tank and the circuit board are disposed via the heat conduction sheet The liquid discharge head according to claim 1, characterized in that.

6. the heat conduction sheet is disposed from the bottom surface of the circuit board through the side surface portion to at least a part of the upper portion of the circuit board The liquid discharge head according to claim 1, characterized in that.

7. the thickness of the heat conduction sheet is 0.1 mm or more and 1.0 mm or less The liquid discharge head according to claim 1, characterized in that.

8. the thickness of the heat conduction sheet is 0.5 mm or more and 1.0 mm or less The liquid discharge head according to claim 1, characterized in that.

9. a flow path through which a refrigerant liquid flows is provided inside the metal frame member The liquid discharge head according to claim 1, characterized in that.

10. comprising the liquid discharge head according to any one of claims 1 to 9 The liquid discharge unit, characterized in that.

11. at least one of a head tank for storing a liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism for supplying the liquid to the liquid discharge head, a maintenance and recovery mechanism for maintaining and recovering the liquid discharge head, and a main scanning movement mechanism for moving the liquid discharge head in the main scanning direction and the liquid discharge head are integrated The liquid discharge unit according to claim 10, characterized in that.

12. A liquid discharging apparatus comprising the liquid discharging head according to any one of claims 1 to 9, or the liquid discharging unit according to claim 10 or 11. Characterized by discharging a liquid.

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