JP2012187838A - Liquid ejecting device - Google Patents

Abstract

An object of the present invention is to make a heat sink contact with a drive circuit and to improve the reliability of connection between an actuator and a flexible cable with a simple configuration.
A heat sink holding member is a deformed portion that bends so that a region of the heat sink holding member that comes into contact with the seal member is closer to the seal member than other regions by attaching the heat sink to the heat sink holding member. have.
[Selection] Figure 5

Description

  The present invention relates to an inkjet head that forms an image by ejecting ink onto a print medium, and an inkjet printer having the inkjet head.

  In an inkjet printer, an inkjet head distributes ink to a plurality of pressure chambers, and ejects ink from nozzles by selectively applying pressure to each pressure chamber. In this ink jet head, there is known one in which a part of the wall of the pressure chamber is constituted by an actuator made of a piezoelectric material. When a voltage is applied to the actuator, the piezoelectric material is deformed, pressure is applied to the pressure chamber, and ink is ejected.

  In order to drive the actuator, a drive signal for driving the actuator is output from the drive circuit. The drive circuit is disposed on the flexible substrate, and the flexible substrate is electrically connected to the actuator in order to supply a drive signal to the actuator.

  However, when a force for peeling the flexible substrate from the actuator is applied to the flexible substrate from the outside, the connection between the flexible substrate and the actuator may be disconnected. As a result, the electrical continuity between the drive circuit and the actuator is interrupted, so that the drive signal output from the drive circuit is not supplied to the actuator, and the actuator cannot be driven. A problem occurs.

  In order to avoid such a problem, Patent Document 1 describes a technique for fixing a flexible substrate by disposing a seal member between a holder body and an actuator. In this technology, since the flexible substrate is fixed to the actuator via the seal member, even if a force that peels off the flexible substrate from the actuator is applied to the flexible substrate from the outside, the connection between the flexible substrate and the actuator is applied. A large force is prevented from being directly applied. The electrical reliability between the flexible substrate and the actuator can be improved.

JP 2003-311953 A

  However, in the technique described in Patent Document 1, a gap is formed between the holder and the actuator, and the seal member is introduced into the gap, so the amount of the introduced seal member fills this gap. If the amount is not sufficient, the flexible substrate and the actuator are not fixed via the seal member, and the flexible substrate and the holder are not fixed via the seal member. In this case, when a force that peels off the flexible substrate from the actuator is applied to the flexible substrate from the outside, it is not possible to suppress a large force from being applied to the connection portion between the flexible substrate and the actuator.

  Another problem is that the drive circuit generates heat. Due to the heat generated in the drive circuit, the drive circuit itself fails or the ink characteristics in the actuator change, leading to variations in ejection quality. In order to avoid this, it is necessary to provide a heat sink that dissipates heat generated in the drive circuit. The heat sink is fixed by the heat sink holding member so as to come into contact with the drive circuit. However, the shape of the heat sink holding member needs to ensure sufficient heat dissipation and consider the ease of mounting the heat sink and miniaturization. .

  It is an object of the present invention to bring a heat sink into contact with a drive circuit and increase the reliability of connection between an actuator and a flexible cable with a simple configuration.

  In order to achieve the above object, a liquid ejection apparatus according to claim 1, a head unit that ejects liquid, and a drive signal that is electrically connected to the head unit and that ejects liquid, A flexible substrate having flexibility, an electronic component disposed on the surface of the flexible substrate and generating the drive signal, a heat sink that releases heat generated by the electronic component to the outside, and the electronic component and the heat sink A heat sink holding member that holds the heat sink so that the heat sink is in contact with the heat sink, and a seal member that is disposed at least between the flexible substrate and the heat sink holding member and that joins the flexible substrate and the heat sink holding member. The heat sink holding member attaches the heat sink to the heat sink holding member. By attaching, it is characterized in that it has a deformable portion that regions in contact with the sealing member of the heat sink holding member is bent to approach the sealing member compared to the other regions.

  According to the first aspect, by attaching the heat sink to the heat sink holding member, the heat sink holding member is deformed, and the region of the heat sink holding member that comes into contact with the seal member approaches the seal member, and between the flexible substrate and the heat sink holding member. Since the flexible substrate and the heat sink holding member are in reliable contact with the seal member, the flexible substrate and the heat sink holding member can be reliably adhered with a simple configuration.

Further, in the liquid ejection device according to claim 2, the heat sink holding member includes a base portion,
A plurality of support portions formed to protrude from the base, and a space in which the heat sink is accommodated is formed in a region sandwiched between the plurality of support portions, and the width of the sandwiched region is the width of the heat sink It is characterized by being smaller.

  According to claim 2, when the heat sink having a width larger than the width of the region is held by the heat sink holding member, the heat sink presses the heat sink holding member and the heat sink holding member is deformed. Due to the deformation of the heat sink holding member, the heat sink holding member is securely bonded to the seal member, so that the flexible substrate and the heat sink holding member can be reliably adhered with a simple configuration.

  According to a third aspect of the present invention, in the liquid ejecting apparatus, the heat sink holding member is made of a metal material.

  According to the third aspect, the heat sink holding member having a large heat capacity can be used for the heat radiation of the IC, and the cooling efficiency can be increased with a simple configuration.

  According to a fourth aspect of the present invention, in the liquid ejection device according to the fourth aspect, the electronic component is disposed between the heat sink and the heat sink holding member.

  According to the fourth aspect, since the electronic component is disposed between the heat sink and the holding member, the electronic component can be fixed. Further, since the heat sink holding member and the electronic component are brought into contact with each other, the electronic component can be radiated with a simple configuration.

  According to a fifth aspect of the present invention, in the liquid discharge apparatus, the heat sink holding member has a head support portion that supports the head unit.

  According to the fifth aspect, the heat sink is held and the head unit is supported by one member, the number of parts is reduced, and the configuration of the liquid ejection device can be simplified.

  Further, in the liquid ejection device according to claim 6, the heat sink includes two portions facing each other, and is configured in a U shape that is elastically deformable as a whole, and an initial set distance between the two portions. Is smaller than the electronic component, and the electronic component is disposed between the two parts.

  According to the sixth aspect, the electronic component and the heat sink can be brought into contact with each other without providing an elastic member, so that the configuration of the liquid ejection device can be simplified.

  According to the present invention, the flexible substrate and the heat sink holding member reliably come into contact with the seal member between the flexible substrate and the heat sink holding member due to the deformation, so that the flexible substrate and the heat sink holding member can be reliably connected with a simple configuration. It can be adhered.

1 is a schematic configuration diagram of a printer of the present invention. 4 is a top view of the inkjet head 4. FIG. The state where the heat sink 29 is not attached to the inkjet head 4 is shown. FIG. 3 is a cross-sectional view taken along the line II in FIG. 2. The state where the heat sink 29 is attached to the inkjet head 4 is shown. It is sectional drawing along the II-II line of FIG. The state where the heat sink 29 is not attached to the inkjet head 4 is shown. It is sectional drawing along the II-II line of FIG. The state where the heat sink 29 is attached to the inkjet head 4 is shown. (A) It is sectional drawing which looked at the supporting member 27 and the heat sink 29 from the scanning direction of embodiment of this invention. A state in which the heat sink 29 is not attached to the support member 27 is shown. (B) It is sectional drawing which looked at the supporting member 27 and the heat sink 29 from the scanning direction of embodiment of this invention. A state in which a heat sink 29 is attached to the support member 27 is shown. (A) It is sectional drawing of the liquid discharge apparatus by the modification of embodiment of this invention. (B) It is sectional drawing of the liquid discharge apparatus by the modification of embodiment of this invention.

  FIG. 1 is a schematic configuration diagram of a printer according to the present embodiment. As shown in FIG. 1, the printer 1 includes a carriage 2, a sub tank 3, an ink jet head 4, four tubes 5, four ink cartridges 6 and the like.

  The carriage 2 reciprocates in the left-right direction (scanning direction) in FIG. The sub tank 3 is attached to the carriage 2, and an ink jet head 4 (liquid ejection head) is attached to the lower surface thereof. For example, black, yellow, cyan, and magenta inks are supplied from the sub tank 3 to the inkjet head 4, and the inkjet head 4 ejects ink from a plurality of nozzles 10 formed on the lower surface thereof.

  The four tubes 5 are made of a flexible material (for example, a material such as synthetic resin), and one end is connected to the sub tank 3 and the other end is connected to the ink cartridge 6. The four ink cartridges 6 are filled with the aforementioned black, yellow, cyan, and magenta inks, respectively, and the ink in the ink cartridge 6 is supplied to the sub tank 3 through the tube 5.

  In the printer 1, ink is ejected from the nozzles 10 of the inkjet head 4 that reciprocates in the scanning direction together with the carriage 2 onto the recording paper P that is transported downward (in the paper feed direction) in FIG. Printing is performed on the recording paper P by discharging.

  Next, the structure of the inkjet head will be described in more detail.

  FIG. 2 is a top view of the inkjet head 4. FIG. 3 is a cross-sectional view taken along the line II of FIG. 4 and 5 are cross-sectional views taken along line II-II in FIG. 2 and 4 show a state in which the heat sink 29 is not attached to the inkjet head 4, and FIGS. 3 and 5 show a state in which the heat sink 29 is attached to the inkjet head 4.

  The inkjet head 4 includes a head unit 4, a COF (Chip On Film) 24, a driver IC 25, a support member 27, a sponge 28, and a heat sink 29, which will be described later, disposed on the inkjet head 4. The head unit 21 has a flow path unit 22 and an actuator unit 23.

  As shown in FIGS. 2 and 3, the inkjet head 4 according to the present embodiment includes a head unit 21 having a substantially rectangular planar shape, a support member 27 for supporting the head unit 21, and the inkjet head 4. A driver IC 25 that supplies a drive signal to the disposed COF 24, the individual electrode 35, and the like, and a heat sink 29 are provided.

  The head unit 21 includes a flow path unit 22 and a plurality of actuator units 23 bonded to the upper surface of the flow path unit 22. The head unit 21 is a substantially rectangular flat plate member for discharging ink onto paper. is there.

  The flow path unit 22 is a substantially rectangular plate-like body, and an ink flow path including a plurality of nozzles 10 and a plurality of pressure chambers (not shown) communicating with the plurality of nozzles 10 is formed in the flow path unit 22. Ink supplied from the ink supply port flows into the ink flow path.

  The actuator unit 23 is disposed on the upper surface of the flow path unit 22. The actuator unit 23 individually applies pressure to ink in a pressure chamber (not shown). In the inkjet head 4, the actuator unit 23 is supplied with a plurality of piezoelectric deformation portions corresponding to each pressure chamber from a driver IC. Ink is ejected from the nozzle 10 communicating with the pressure chamber by being individually deformed based on the drive signal and applying pressure to the ink in each pressure chamber individually.

  A COF 24 is disposed on the upper surface of the actuator unit 23. The COF 24 is drawn upward from the end portion on the upper surface of the actuator unit 23 (the right end portion in FIGS. 2 and 4), and the actuator unit 23 is driven on the upper surface of the portion in the middle of the extracted portion. A driver IC 25 is mounted. The drawn out end of the COF 24 is connected to a drive board (not shown). In addition, a wiring 241 made of a conductive material such as a copper foil is disposed on the COF 24, and the driver IC 25 is electrically connected to the drive substrate and the actuator unit 23 through the wiring 241 on the COF 24.

  Further, a support member 27 is disposed on the upper surface of the actuator unit 23 where the COF 24 is disposed. The support member 27 is for connecting the head unit 21 and a heat sink 29 described later. The support member 27 is partially bonded to the upper surface of the head unit 21 to hold the head support portion 271 that supports the head unit 21, and is bonded to the upper surface of the head support portion 271 to hold the head support portion 271. The base 272 includes four engaging portions 273 extending from the base to the side opposite to the head unit. The head support portion 271 extends in parallel with the scanning direction as shown by a dotted line in FIG. 2, and the lower portion thereof is in contact with the upper surface of the head unit 21 as shown in FIG. 4. At this time, the position where the head support portion 271 and the head unit 21 are in contact avoids a region facing the pressure chamber.

  The deforming portion 2721 is an end portion of the base portion 272 and is a portion where the engaging portion 273 is erected, and is deformed as the heat sink 29 is attached, as will be described later.

  Further, a sponge 28 (elastic member) is disposed on a portion of the upper surface of the base 272 facing the driver IC 25. The sponge 28 supports the driver IC 25 from below. The COF 24 is arranged so as to be sandwiched between the sponge 28 and the driver IC 25.

  A heat sink 29 is disposed on the upper surface of the driver IC 25 so as to be in close contact with the upper surface of the driver IC 25. The heat sink 29 is a substantially rectangular parallelepiped member for releasing heat generated in the driver IC 25.

  As shown in FIGS. 6A and 6B, the length a of the heat sink 29 in the paper feed direction is configured to be larger than the length b between the two engaging portions 273 in the paper feed direction. When the heat sink 29 is disposed so as to be in close contact with the upper surface of the driver IC 25, the heat sink 29 presses the engaging portion 273 in a direction parallel to the paper feeding direction. The engagement portion 273 is deformed in a direction in which the two engagement portions 273 are separated from each other as the heat sink 29 is pressed. As a result of the deformation in the direction in which the engaging portions 273 are separated from each other, the length between the two engaging portions 273 is substantially equal to the length of the heat sink 29, so the heat sink 29 is between the two engaging portions 273. It becomes possible to arrange | position. At this time, as the engaging portion 273 is deformed, the deforming portion 2721 of the base 272 formed integrally with the engaging portion 273 is also deformed. The deforming portion 2721 is deformed in a direction opposite to the heat sink 29 (direction on the head unit 21 side) when the engaging portion 273 is deformed in the paper feeding direction. That is, the deforming portion 2721 is closer to the head unit. Therefore, the distance between the base 272 and the head unit 21 is smaller in the state where the heat sink 29 is attached than in the state where the heat sink 29 is not attached. The effect of this will be described later. At this time, when the deformable portion 2721 is formed of a material having rigidity smaller than that of the engaging portion 273, the deformable portion 2721 is easily deformed. In addition, the shape of the deformable portion 2721 can be easily changed. For example, the deformed portion 2721 can be formed thinner than the base portion 272. At this time, the deformation portion 2721 is easily deformed.

  In a state where the heat sink 29 is attached to the support member 27, the sponge 28 presses the driver IC 25 through the COF 24. Since the driver IC 25 and the heat sink 29 are in close contact with each other, heat generated when the driver IC 25 is driven is transmitted to the heat sink 29, and the heat is released to the outside through the heat sink 29.

  The support member 27 can be formed of a material having high thermal conductivity such as metal. Since the support member 27 and the heat sink 29 are in contact with each other, heat generated by the driver IC 25 is transmitted to the support member 27 through the heat sink 29, and the heat is released to the outside through the heat sink 29. Therefore, since the support member 27 releases the heat generated by the driver IC 25 to the outside, the heat dissipation efficiency can be increased.

  Next, the connection between the actuator unit 23 and the COF 24 will be described.

  The actuator unit 23 includes a plurality of piezoelectric sheets formed to have the same thickness of about 15 μm. These piezoelectric sheets are formed into a continuous layered flat plate (continuous flat plate layer) so as to be disposed across a number of pressure chambers formed in one ink discharge region in the inkjet head 4.

  An individual electrode 35 having a thickness of about 1 μm is formed on the upper surface of the actuator unit 23 and corresponding to the pressure chamber.

  The COF 24 is a member for connecting the individual electrode 35 and the common electrode (not shown) of the actuator unit 23 to the driver IC 25. As shown in FIGS. 3 to 5, the wiring 241 on the COF 24 is an actuator unit. Electrically joined to the individual electrode 35a disposed on the upper surface of the solder 23 by soldering.

  A predetermined gap is formed between the lower surface of the base 272 and the upper surface of the actuator unit 23.

  A seal member 26 is disposed between the lower surface of the base 272 and the upper surface of the actuator unit 23 so as to sandwich the COF 24. The seal member 26 fixes the COF 24 to the actuator unit 23 and the base 272. As the seal member 26, an adhesive, a double-sided tape, or the like is used. Examples of the adhesive include those made of a silicon-based material.

  As a result, it is possible to prevent stress from being applied to the connecting portion between the actuator unit 23 and the COF 24 and to hold the COF 24 with certainty as will be described later.

  Since the COF 24 including the wiring 241 electrically connected to the actuator unit 23 is fixed to the vicinity of the end of the flow path unit 22 and the base 272 which is a part of the support member 27 by the seal member 26, Even when an external force is applied to the COF 24 from the actuator unit 23, it is possible to prevent a large force from being directly applied to the connecting portion between the actuator unit 23 and the COF 24. Therefore, since the COF 24 is less likely to be peeled off from the actuator unit 23, the reliability of the electrical connection between the actuator unit 23 and the driver IC 25 can be improved.

  At this time, if the sealing member 26 is also disposed between the COF 24 and the actuator unit 23 and the COF 24 and the actuator unit 23 are joined, a large force is directly applied to the connecting portion between the actuator unit 23 and the COF 24. The addition is further suppressed.

  However, the amount of the seal member 26 introduced between the lower surface of the base portion 272 and the upper surface of the flow path unit 4 is small, and the space between the lower surface of the base portion 272 and the upper surface of the flow path unit 4 may not be completely closed. Conceivable. In such a case, the COF 24 is separated from the actuator unit 23 and the base 272, and when a force is applied from the outside to the COF 24 so as to peel off the actuator unit 23, the connection between the actuator unit 23 and the COF 24 is applied. There is a possibility that a large force is directly applied and the connecting portion is peeled off.

  On the other hand, in the present embodiment, as described above, the distance between the base 272 and the head unit 21 is smaller when the heat sink 29 is attached than when the heat sink 29 is not attached. . Therefore, if there is a sufficient amount of the sealing member 26 to block between the lower surface of the base portion 272 and the upper surface of the flow path unit 4, the COF 24 is reliably fixed by the sealing member 26.

  Next, a modification of the embodiment of the present invention will be described. 7A and 7B are cross-sectional views of a liquid ejection apparatus according to a modification of the embodiment of the present invention.

  7A and 7B is different from the liquid discharge device of FIGS. 3 to 5 in FIG. 3 to FIG. 5 in that the driver IC 25 is arranged on the upper surface of the sponge 28 and the elasticity of the sponge 28 is changed. The driver IC 25 is in close contact with the heat sink 29 by force, whereas in FIGS. 7A and 7B, the driver IC 25 is sandwiched between substantially U-shaped heat sinks 290 and does not have a sponge configuration. Is a point. In the modification, the other configuration is the same as the configuration of the printer described with reference to FIGS. 7 (a) corresponds to FIG. 3, and FIG. 7 (b) corresponds to FIG. 5. As described in FIGS. 3 and 5, the support member 27 is deformed as the heat sink 290 is attached. In contact with the seal member 26.

  The heat sink 290 in the modified example is formed of an elastically deformable material, includes two portions facing each other, and is configured in a U shape as a whole. A driver IC 25 is disposed between the two portions facing each other. In a state where the driver IC 25 is not disposed, the length (initial setting distance) between the two facing portions is smaller than the length of the driver IC 25. Therefore, when the driver IC 25 is disposed at two opposite portions of the heat sink 290, the heat sink 290 presses the driver IC 25 so as to come into contact with the driver IC 25. Therefore, the heat sink 290 and the driver IC 25 can be reliably contacted without preparing a member such as a sponge to press the driver IC 25. Since there is no need to newly prepare a member for pressing the driver IC 25, the number of parts can be reduced, the cost can be suppressed, and the configuration can be simplified.

1 Printer 2 Carriage 3 Subtank 4 Inkjet Head (Liquid Ejecting Device)
5 Four tubes 6 Ink cartridge 10 Nozzle P Recording paper 21 Head unit (head unit)
22 Flow path unit 23 Actuator unit 24 COF (flexible substrate)
241 Wiring 25 Driver IC (electronic component)
27 Support member (heat sink holding member)
28 Sponge 29 Heat sink (heat sink)
35 Individual electrode 271 Head support (head support)
272 Base (base)
273 Engagement part (support part)
2721 Deformation part (deformation part)
26 Seal member (seal member)
290 heat sink

Claims (6)

A head unit for discharging liquid;
A flexible substrate that is electrically connected to the head unit and supplies a drive signal for discharging liquid; and a flexible substrate;
An electronic component disposed on the surface of the flexible substrate and generating the drive signal;
A heat sink that releases heat generated in the electronic component to the outside;
A heat sink holding member for holding the heat sink so that the electronic component and the heat sink are in contact with each other;
A seal member disposed at least between the flexible substrate and the heat sink holding member, and joining the flexible substrate and the heat sink holding member;
The heat sink holding member has a deformed portion that bends so that a region of the heat sink holding member that contacts the seal member is closer to the seal member than other regions by attaching the heat sink to the heat sink holding member. A liquid ejecting apparatus comprising: The heat sink holding member is
The base,
A plurality of support portions formed protruding from the base,
A space in which a heat sink is accommodated is configured in a region sandwiched between the plurality of support portions,
The liquid ejection apparatus according to claim 1, wherein a width of the sandwiched region is smaller than a width of the heat sink. The liquid discharge apparatus according to claim 1, wherein the heat sink holding member is made of a metal material. 4. The liquid ejection device according to claim 1, wherein the electronic component is disposed between the heat sink and the heat sink holding member. The liquid discharge apparatus according to claim 1, wherein the heat sink holding member includes a head support portion that supports the head unit. The heat sink includes two portions facing each other, and is configured in a U shape that is elastically deformable as a whole.
The initial set distance between the two parts is smaller than the electronic component,
The liquid ejecting apparatus according to claim 1, wherein the electronic component is disposed between the two parts.

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