Actuator, liquid discharge head, and liquid feeding device

Abstract

To provide an actuator capable of reducing position fluctuation dependent on a temperature.SOLUTION: This actuator comprises: a drive body that receives a voltage to elongate / shrink in one direction; and a drive body support member having a butting unit that butts one end side of the drive body in the elongating / shrinking direction, and a contact part provided so as to be contactable with the drive body and extending from the butting unit to the other end side of the drive body. At least the butting unit of the drive body support member has a linear expansion coefficient of the drive body and a linear expansion coefficient of a reverse code.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an actuator, a liquid ejection head, and a liquid applying device. [Background technology]

[0002] Patent document 1 describes a liquid ejection head having a valve body (needle valve) that opens and closes a liquid ejection port (nozzle), a driver body (piezoelectric element) that drives the valve body, and a housing that holds the valve body and driver body, in which the head has a heat sink that is in contact with the driver body via an elastic heat transfer layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-073547 Summary of the Invention [Problem to be solved by the invention]

[0004] In actuators used in this type of liquid ejection head, etc., it is desirable to further reduce positional fluctuations caused by thermal deformation of the driving body, which depends on temperature. [Means for solving the problem]

[0005] The present invention is characterized in that it comprises a driver that expands and contracts in one direction when a voltage is applied to it, a driver support member having an abutment portion that abuts against one end of the driver in the expanding and contracting direction, and a contact portion that extends from the abutment portion to the other end of the driver and is arranged so as to be able to come into contact with the driver, and at least the abutment portion of the driver support member has a linear expansion coefficient with an opposite sign to that of the linear expansion coefficient of the driver. Effect of the Invention

[0006] According to the present invention, it is possible to provide an actuator capable of reducing temperature-dependent positional fluctuations. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an overall configuration diagram showing an example of an actuator according to an embodiment. [Diagram 2] FIG. 1 is an explanatory diagram showing a configuration example of a driver support member; [Diagram 3] FIG. 4 is a graph showing the relationship between driving time and temperature rise. [Figure 4] FIG. 11 is an explanatory diagram showing the relationship between drive time and tip displacement amount. [Diagram 5] 11A and 11B are explanatory diagrams showing examples of determining the length of abutting portions of a driver support member. [Figure 6] FIG. 4 is an explanatory diagram showing an example of assembly of a driver support member. [Figure 7] FIG. 4 is an explanatory diagram showing the positional relationship between a driver and a driver support member. [Figure 8] 5 is an explanatory diagram of the natural vibration of a driver support member. FIG. [Figure 9] 13A and 13B are explanatory diagrams showing modified examples of the driver support member. [Figure 10] FIG. 13 is an explanatory diagram showing another modified example of the driver support member. [Figure 11] FIG. 1 is a diagram showing an overall configuration of an example of a liquid ejection head according to an embodiment. [Figure 12] FIG. 4 is a diagram showing the overall configuration of another example of a liquid ejection head according to an embodiment. [Figure 13] FIG. 4 is a block diagram showing an example of a control system for the liquid ejection head. [Figure 14] FIG. 4 is a block diagram showing an example of a hardware configuration of a control unit. [Figure 15] FIG. 2 is an overall configuration diagram showing an application example of a liquid ejection head. [Figure 16] FIG. 2 is an explanatory diagram showing a first example of an apparatus for applying a liquid according to the embodiment. [Figure 17] FIG. 2 is an explanatory diagram showing an example of use of the first example of the liquid applying device. [Figure 18] FIG. 4 is an explanatory diagram showing a second example of the device for applying a liquid according to the embodiment. [Figure 19] FIG. 13 is a perspective view of a carriage portion of a second example liquid dispensing device. [Figure 20] FIG. 11 is an explanatory diagram showing a third example of the device for applying a liquid according to the embodiment. [Figure 21] FIG. 13 is an explanatory diagram showing another example of the device for applying the liquid of the third example. [Figure 22] FIG. 13 is an explanatory diagram showing a modified example of the liquid applying device of the third example. [Figure 23] FIG. 11 is an explanatory diagram showing a fourth example of the device for applying a liquid according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted.

[0009] <Actuator configuration> FIG. 1 is a diagram showing an overall configuration of an example of an actuator according to an embodiment.

[0010] Piezoelectric actuator 130, which is an example of an actuator, includes a piezoelectric element 132 and a holder 136. Piezoelectric element 132 expands and contracts in one direction (Z direction in the figure) when a voltage is applied to an external electrode, for example. Holder 136 has end portion 136a and rim portion 136b. End portion 136a is disposed at one end of piezoelectric element 132 in the direction in which it expands and contracts (end portion on the negative side of Z direction in the figure), and end portion 136a is joined to piezoelectric element 132 by joint portion 137.

[0011] Of the end portion 136a and rim portion 136b that constitute the holder 136, at least the end portion 136a is formed from a material having a linear expansion coefficient with an opposite sign to that of the piezoelectric element 132. "Linear expansion coefficient with an opposite sign" means, for example, that in the case where the piezoelectric element 132 is a piezoelectric element that has the property of shrinking due to self-heating or an increase in the ambient temperature, the end portion 136a has the property of expanding due to an increase in temperature.

[0012] The rim portion 136b extends from the bottom of the end portion 136a toward the other end (the end on the positive side in the Z direction in the figure) of the piezoelectric element 132. The inner surface of the rim portion 136b contacts the outer surface of the piezoelectric element 132 with a force that does not interfere with the expansion and contraction action when a voltage is applied to the piezoelectric element 132. In addition, one end of the rim portion 136b (the end on the negative side in the Z direction in the figure) is fixed to the bottom of the end portion 136a.

[0013] With the above configuration, heat generated by the self-heating of the piezoelectric element 132 is transferred from the piezoelectric element 132 to the rim portion 136b, and then transferred to the end portion 136a via the rim portion 136b. The end portion 136a is thermally deformed in the opposite direction to the thermal deformation of the piezoelectric element 132 due to the heat received from the rim portion 136b. In other words, when the piezoelectric element 132 is thermally deformed in the contracting direction in the Z direction, the end portion 136a is thermally deformed in the expanding direction, and the negative thermal deformation of the piezoelectric element 132 is offset by the positive thermal deformation of the end portion 136a. Here, the piezoelectric element 132 is an example of a "driver", and the holder 136 is an example of a "driver support member". The end portion 136a is an example of a "butting portion", and the rim portion 136b is an example of a "contact portion".

[0014] As described above, the piezoelectric actuator 130 of this embodiment includes a piezoelectric element 132 that expands and contracts in one direction (for example, Z direction) when a voltage is applied, an end portion 136a that abuts against one end of the piezoelectric element 132 in the direction in which the piezoelectric element 132 expands and contracts, and a holder 136 having a rim portion 136b that extends from the end portion 136a to the other end side of the piezoelectric element 132 and is provided so as to be able to come into contact with the piezoelectric element 132, and at least the end portion 136a of the holder 136 has a linear expansion coefficient with an opposite sign to that of the piezoelectric element 132. As a result, for example, when the piezoelectric element 132 is thermally deformed in a direction in which it contracts, the end portion 136a is thermally deformed in a direction in which it expands, and the thermal deformation of the piezoelectric element 132 is offset. As a result, an actuator that is less susceptible to the influence of thermal deformation of the driving body that depends on temperature and can reduce positional fluctuation can be provided.

[0015] The rim portion 136b is not limited to a configuration in which it directly contacts the piezoelectric element 132, and may be configured to be in indirect contact with the piezoelectric element 132 by providing a heat transfer layer 138 between the inner surface of the rim portion 136b and the outer surface of the piezoelectric element 132. In this case, since the heat transfer layer 138 needs to be designed not to impede the expansion and contraction action when a voltage is applied to the piezoelectric element 132, it is preferable to form the heat transfer layer 138 using heat conductive grease. Examples of heat conductive grease include silicon grease, silver grease, diamond grease, etc., each having a thermal conductivity of 0.5 to 16 W / mK. In addition, the heat transfer layer 138 needs to be heat resistant against the self-heating of the piezoelectric element 132, and it is preferable that the heat resistance temperature of the heat transfer layer 138 exceeds 100°C.

[0016] As described above, in this embodiment, the heat transfer layer 138 is provided between the piezoelectric element 132 and the rim portion 136b, and the piezoelectric element 132 and the rim portion 136b are in contact with each other via the heat transfer layer 138. This can increase the efficiency of heat transfer between the piezoelectric element 132 and the holder 136.

[0017] As described above, the heat transfer layer 138 is provided so as to be operable in the direction in which the piezoelectric element 132 expands and contracts. This allows heat to be transferred to the holder 136 without impeding the expansion and contraction action that occurs when a voltage is applied to the piezoelectric element 132.

[0018] The end portion 136a and the rim portion 136b of the holder 136 may be formed from two or more separate members, or the end portion 136a and the rim portion 136b may be integrated into a single member. In the latter case, from the viewpoint of offsetting the thermal deformation of the piezoelectric element 132, the material used for the end portion 136a is given priority, and the rim portion 136b is formed from the same material as the end portion 136a.

[0019] As described above, in this embodiment, the end portion 136a and the rim portion 136b are made of different materials. This makes it possible to select materials suited to the characteristics of each of the end portion 136a and the rim portion 136b, and to efficiently deal with heat. In addition, the design freedom in material selection can be increased. For example, by using aluminum, which has a large linear expansion coefficient, as the material for the end portion 136a and copper, which has a large thermal conductivity, as the material for the rim portion 136b, the heat of the piezoelectric element 132 can be transferred to the end portion 136a with high efficiency. This can increase the responsiveness of the thermal deformation of the end portion 136a, which offsets the thermal deformation caused by the temperature change of the piezoelectric element 132.

[0020] Furthermore, the difference in thermal deformation between the piezoelectric element 132 and the rim portion 136b may be reduced by using a material with a small linear expansion coefficient for the material of the rim portion 136b. This reduces the stress that occurs at the contact portion between the piezoelectric element 132 and the rim portion 136b when the temperature of the piezoelectric element 132 rises. The rim portion 136b may be made of a ceramic material with a small linear expansion coefficient and high thermal conductivity, such as silicon carbide or aluminum nitride. In this way, by constructing the end portion 136a and the rim portion 136b from different materials, it is possible to design their respective linear expansion coefficients and thermal conductivities separately.

[0021] As described above, the end portion 136a and the rim portion 136b are made of a single member. This reduces the number of parts and simplifies the configuration, which makes it possible to reduce manufacturing costs. In addition, since there is no connecting portion connecting the end portion 136a and the rim portion 136b, heat transfer loss at the connecting portion can be eliminated.

[0022] In the following, a description will be given based on a holder configuration in which the end portion and the rim portion are integrally formed.

[0023] Fig. 2 is an explanatory diagram showing an example of the configuration of a driver support member. Of these, Fig. 2(a) is a side view showing a first example of the configuration of the driver support member, and Fig. 2(a-1) is a cross-sectional view taken along line AA in Fig. 2(a). Fig. 2(b) is a side view showing a second example of the configuration of the driver support member, and Fig. 2(b-1) and Fig. 2(b-2) are cross-sectional views taken along line BB in Fig. 2(b).

[0024] In the first configuration example, as shown in Fig. 2(a-1), the rim portion 136b contacts three of the four side surfaces of the quadrangular prism-shaped piezoelectric element 132 via the heat transfer layer 138, and opens one side of the piezoelectric element 132. The outer shape of the cross section of the piezoelectric element 132 is not limited to a rectangle. For example, the piezoelectric element may have an outer shape of a polygon, such as a pentagonal, hexagonal, or octagonal cross section.

[0025] Furthermore, the cross-sectional shape of the piezoelectric element 132 may be an octagonal cross-sectional shape by chamfering each vertex of the rectangular cross-sectional shape (C-face processing). Furthermore, the side surface of the piezoelectric element 132 where the rim portion 136b is open may be one or more open, and the side surface where the rim portion 136b is open may be two or more. For example, when the cross-sectional shape of the piezoelectric element 132 is a hexagon, by providing the rim portion 136b so that two side surfaces of the piezoelectric element 132 are open, it becomes possible to insert the piezoelectric element 132 into the holder 136 from a portion where the rim portion 136b is not present. This allows the piezoelectric element 132 to be easily assembled to the holder 136.

[0026] That is, the cross section (XY plane) of the piezoelectric element 132 in a direction perpendicular to the direction in which it expands and contracts due to the application of voltage (Z direction in the figure) forms a polygonal outer shape having four or more sides, and the rim portion 136b is provided so as to be able to contact the remaining sides of the four or more sides of the piezoelectric element 132, excluding at least one side. This makes it possible to access the piezoelectric element 132 and the holder 136 from the side (side surface) on which the rim portion 136b is not provided, making it possible to easily perform the joining work between the piezoelectric element 132 and the holder 136, etc. Furthermore, when the heat transfer layer 138 is provided, it also becomes easier to apply heat conductive grease, and the thickness of the heat transfer layer 138 can be made uniform.

[0027] The second configuration example differs from the first configuration example in that a rim portion 136b is provided so as to cover the entire circumference of the piezoelectric element 132. In the case of the second configuration example, the piezoelectric element 132 is not limited to a square prism shape, but may be a columnar (or cylindrical) shape. When the piezoelectric element 132 is square shaped, the rim portion 136b contacts the four side surfaces of the piezoelectric element 132 via the heat transfer layer 138 as shown in FIG. 2(b-1). When the piezoelectric element 132 is columnar (or cylindrical), the rim portion 136b contacts the outer peripheral surface of the piezoelectric element 132 via the heat transfer layer 138 as shown in FIG. 2(b-2).

[0028] That is, the cross section (XY plane) of the piezoelectric element 132 in a direction perpendicular to the direction in which it expands and contracts due to the application of a voltage (Z direction in the figure) has a polygonal shape having four or more sides, or a circular shape, and the rim portion 136b is provided so as to be able to contact the entire circumference of the outer shape of the piezoelectric element 132. By making the cross section a polygonal shape having four or more sides, the interior angles of each vertex can be made right angles or obtuse angles, so that the rim portion 136b can be in contact with the vicinity of the vertices. In addition, since the interior angles of the vertices of the polygonal shape of the cross section are not acute angles, an increase in the heat transfer resistance at the vertices can be suppressed. It is preferable that the number of sides of the polygonal shape of the cross section is large because the surface area of ​​the piezoelectric element 132 can be increased, but since processing of the piezoelectric element 132 becomes difficult, it is preferable that the number of sides of the polygonal shape is 16 or less. This increases the contact area between the piezoelectric element 132 and the rim portion 136b, increasing the amount of heat flow, and therefore the amount of heat transferred from the rim portion 136b to the end portion 136a, making it possible to further improve the responsiveness to thermal deformation. In addition, because the responsiveness is improved, the length of the holder 136 in the Z direction can be made shorter, making it possible to reduce the size of the entire piezoelectric actuator 130.

[0029] The heat flow rate Q can be expressed by Equation 1 when the thermal conductivity is k, the contact area is A, the temperature difference is ΔT, and the heat flow distance is d. The larger the contact area A, the larger the heat flow rate Q. Q = k A(ΔT / d) Equation 1

[0030] In addition, in equation 1, the contact area A can be expressed by equation 2 when the cross-sectional area of ​​the piezoelectric element is Ap, the width of the piezoelectric element is Ax, the length of the rim portion 136b of the holder is L, and the number of rim portions 136b formed on the holder is N. A=Ap+(Ax L)N...Equation 2

[0031] When Equation 2 is considered for the piezoelectric actuator 130 shown in FIG. 2, the cross-sectional area Ap is the product of the length of the piezoelectric element 132 in the X direction and the length of the piezoelectric element 132 in the Y direction.

[0032] Furthermore, the width Ax is the length of the piezoelectric element 132 in the X direction and the length in the Y direction, and in formula 2, the lengths in both the X direction and the Y direction are set to be equal.

[0033] The length L is the length of the rim portion 136b in the Z direction, and the number of rim portions N is the number of rim portions 136b (number of faces) provided around the piezoelectric element 132 in the XY plane.

[0034] For example, if the external dimensions (X direction x Y direction x Z direction) of the piezoelectric element are 3 mm x 3 mm x 40 mm, the length L of the rim portion is 30 mm, and the number of rim portions N is increased to 2, 3, or 4, then the contact area A increases as the number of rim portions N increases, as follows: [In the case of N=2] A = Ap + (Ax L) × 2 =(3×3)+(3×30)×2 =189mm 2 [In the case of N=3] A = Ap + (Ax L) × 3 =(3×3)+(3×30)×3 =279mm 2 [In the case of N=4] A = Ap + (Ax L) × 4 =(3×3)+(3×30)×4 =369mm 2

[0035] As described above, the contact area A between the piezoelectric element 132 and the holder 136 can be increased by increasing the number N of rim portions. The larger the contact area A, the better the responsiveness of heat transfer from the piezoelectric element 132 to the holder 136.

[0036] Furthermore, a longer length L of rim portion 136b in the Z direction can increase the contact area A between piezoelectric element 132 and holder 136, improving the responsiveness of heat transfer from piezoelectric element 132 to holder 136. Since piezoelectric element 132 generates the most heat in its center in the Z direction when driven, it is preferable that the length of rim portion 136b in the Z direction be at least half the length of piezoelectric element 132 in the Z direction. This allows rim portion 136b to efficiently transfer heat from the center portion of piezoelectric element 132, which generates the most heat, to end portion 136a.

[0037] Furthermore, the length L of the rim portion 136b in the Z direction may be shorter than the length of the piezoelectric element 132 in the Z direction. The amount of heat generated at the lower end of the piezoelectric element 132 is smaller than that at the center, and the amount of movement (deformation) due to driving is the largest. If the rim portion 136b is provided over the length of the piezoelectric element in the Z direction, the contact area between the rim portion 136b and the piezoelectric element 132 becomes large, and the two come into contact even at the lower end where the amount of movement (deformation) due to driving is the largest. Therefore, the amount of sliding and stress between the rim portion 136b and the piezoelectric element 132 increases. Therefore, it is preferable that the length of the rim portion 136b in the Z direction is shorter than the length of the piezoelectric element 132 in the Z direction.

[0038] Fig. 3 is an explanatory diagram showing the relationship between drive time and temperature rise. Of these, Fig. 3(a) is a graph based on a comparative example, showing the temperature change when the end part of a rimless configuration, i.e., N=0, is joined to a piezoelectric element. Fig. 3(b) is a graph based on an embodiment of the present invention, showing the temperature change in a three-sided rim configuration, i.e., N=3 as shown in Fig. 2(a) and Fig. 2(a-1), as an example.

[0039] In each graph, the vertical axis indicates the temperature rise (°C) and the horizontal axis indicates the driving time of the piezoelectric element (sec). Each graph shows the temperature change of the piezoelectric element and the end portion when the piezoelectric element is driven for 60 seconds at a specified duty.

[0040] In both Fig. 3(a) and Fig. 3(b), the linear expansion coefficient of the piezoelectric element is -5×10 -6 ~-10×10 -6 (1 / °C), the linear expansion coefficient of the holder is 23.5×10 -6 (1 / °C) and the material of the holder is aluminum. By selecting a material that has a difference of about 2 to 3 times between the linear expansion coefficient of the piezoelectric element and that of the holder, it is possible to shorten the length of the end portion of the holder (hereinafter also referred to as "end portion length" or "butting portion length"). The end portion length (butting portion length) will be described later.

[0041] In the comparative example (no rim) configuration, as shown in Fig. 3(a), the temperature of the piezoelectric element rises by 23°C after 60 seconds, and the temperature of the end portion rises by 11°C, with the difference in temperature rise ΔT between the piezoelectric element and the end portion being 12°C. In contrast, in the embodiment (three-sided rim) configuration, as shown in Fig. 3(b), the temperature of the piezoelectric element rises by 15°C after 60 seconds, and the temperature of the end portion rises by 12.5°C, with the difference in temperature rise ΔT being 2.5°C.

[0042] Thus, in the comparative example, ΔT increases as the driving time of the piezoelectric element becomes longer, and the effect of the end portion offsetting the thermal deformation of the piezoelectric element can only be obtained for a temporary period from the start of driving of the piezoelectric element. In contrast, in the embodiment, ΔT does not become large as in the comparative example, so the effect of the end portion offsetting the thermal deformation of the piezoelectric element is maintained. In addition, the increased contact area improves the responsiveness of heat conduction and suppresses the temperature rise of the piezoelectric element itself, thereby reducing the thermal deformation (variation in the amount of expansion and contraction) of the piezoelectric element, which is dependent on temperature.

[0043] It is desirable to set the contact area of ​​the rim of the holder and the length of the end and rim after measuring the linear expansion coefficient of the piezoelectric element. For example, some piezoelectric elements have a positive linear expansion coefficient, in which case the piezoelectric element thermally deforms in the direction of expansion due to a rise in temperature. In such a case, it is necessary to use a material with a negative linear expansion coefficient for the end. A material with a negative linear expansion coefficient can be obtained by synthesizing a material with a negative linear expansion coefficient, such as zirconium tungstate phosphate (Zr2WO4(PO4)2). As a result, when the piezoelectric element thermally deforms in the direction of expansion due to a rise in temperature, the end deforms in the direction of contraction, offsetting the thermal deformation of the piezoelectric element.

[0044] FIG. 4 is an explanatory diagram showing the relationship between drive time and tip displacement amount, where FIG. 4(a) is a diagram comparing the relationship between the presence or absence of an end portion and the tip displacement amount, and FIG. 4(b) is an explanatory diagram providing additional information about the length of the end portion.

[0045] In Figure 4(a), the vertical axis represents the tip displacement (μm) and the horizontal axis represents the driving time (sec) of the piezoelectric element, and the figure shows the change in the tip displacement of the piezoelectric element when the piezoelectric element is driven for 1000 seconds at a specified duty.

[0046] In Figure 4(a), the line connecting the triangles (▲) indicates the case of a piezoelectric element 132 alone without a holder 136. The line connecting the circles (○) indicates the case of a holder 136 formed with an end portion having a length of 7 mm, and the line connecting the squares (□) indicates the case of a holder 136 formed with an end portion having a length of 14 mm. The material of the holder 136 (end portion 136a, rim portion 136b) is both aluminum.

[0047] 4(b), the "end length (abutting length)" is the length z1 from the end face of the end portion 136a to the surface against which the piezoelectric element 132 abuts. Also, the "tip displacement amount" is the displacement amount in the Z direction of the tip position of the piezoelectric element 132, that is, the amount of thermal deformation in the Z direction caused in the piezoelectric element 132 depending on the temperature.

[0048] Specifically, a change in the tip displacement amount to the negative side as shown by the line connecting the triangles in Fig. 4(a) means that the tip position of the piezoelectric element 132 has been displaced more negatively than 0 in Fig. 4(b). Conversely, a change in the tip displacement amount to the positive side as shown by the line connecting the circles and the line connecting the squares in Fig. 4(a) means that the tip position of the piezoelectric element 132 has been displaced more positively than 0 in Fig. 4(b). Data comparing such tip displacement amounts is used when determining the end portion length z1 of the end portion 136a. An example will be described below.

[0049] FIG. 5 is an explanatory diagram showing an example when determining the length of the abutting portion of the driver support member.

[0050] In Fig. 5, the vertical axis indicates the tip displacement (μm) and the horizontal axis indicates the end length (abutment length) z1 (mm). Fig. 5 plots the tip displacement at 1000 seconds of drive time when the tip displacement reaches saturation for each of the configurations in Fig. 4(a) with no holder, an end length of 7 mm, and an end length of 14 mm.

[0051] The end length z1 of the holder 136 is selected to be an optimal value in light of the desired tip displacement amount based on the data in Fig. 5. For example, if it is desired to set the tip displacement amount at the time point of 1000 seconds of drive time to 0, the end length z1 is selected to be 4.8 mm.

[0052] FIG. 6 is an explanatory diagram showing an example of assembling a driver support member, where FIG. 6(a) shows the state before assembling the driver support member (holder), and FIG. 6(b) shows the state after assembling the driver support member (holder).

[0053] An actual piezoelectric element 132 has electrodes, and lead wires 132a and 132b for applying a voltage extend from the electrodes, as shown in FIG. 6(a), for example.

[0054] For this reason, it is desirable to provide the rim portion 136b with a length such that the bottom end of the rim portion 136b does not hit the lead wires 132a, 132b as shown in Fig. 6(b) when the holder 136 is attached to the piezoelectric element 132. In this case, it is preferable to extend the rim portion 136b to a position just before the lead wires 132a, 132b and maximize the contact area with the outer surface of the piezoelectric element 132 in order to improve the responsiveness of heat conduction.

[0055] Next, the relationship between the central position of the driver (piezoelectric element) and the center of gravity of the driver support member (holder) will be described with reference to FIGS.

[0056] Fig. 7 is an explanatory diagram showing the positional relationship between the driver and the driver support member. Fig. 7(a) and Fig. 7(b) are cross-sectional views taken in a direction perpendicular to the direction of expansion and contraction of the piezoelectric element when the piezoelectric actuator is mounted in the housing of the mounting section. Fig. 8 is an explanatory diagram of the natural vibration of the driver support member.

[0057] 7, the piezoelectric actuator 130 is loaded into a loading hole Fa provided in a mounting housing F. The mounting housing F is a housing for various devices or units in which the piezoelectric actuator 130 is mounted.

[0058] In the case where the holder 136 (rim portion 136b) covers three of the four sides of the rectangular prism-shaped piezoelectric element 132, the piezoelectric element 132 and the holder 136 are likely to shift toward the open surface where the rim portion 136b is not present. Therefore, as shown in Fig. 7(b), it is considered that the holder 136 may be joined in a state where the center of gravity o2 is shifted from the center o1 of the piezoelectric element 132.

[0059] Since the piezoelectric element 132 and the holder 136 are fixed only by the joint 137, if the holder center of gravity position o2 and the piezoelectric element center position o1 are misaligned, a natural vibration occurs in the holder 136 when the piezoelectric element is driven. When the piezoelectric element 132 is driven at high frequency, the natural vibration causes the holder 136 to vibrate laterally in the direction of the arrow in Fig. 8, which may cause problems such as a decrease in the efficiency of heat transfer to the holder 136 or peeling off of the joint 137.

[0060] Therefore, in this embodiment, as shown in Fig. 7(a), the center of gravity o2 of the holder 136 is set to be substantially the same as the center position o1 of the piezoelectric element 132, thereby solving the above problem. The center of gravity o2 of the holder 136 and the center position o1 of the piezoelectric element 132 are preferably within a range of 1 / 10 or less of the total width of the piezoelectric element 132 (width in the left-right direction in Fig. 7(b)), and more preferably within a range of 1 / 20 or less. By setting the center of gravity o2 and the center position o1 within the aforementioned range, the influence of lateral shaking due to natural vibration can be kept within an allowable range.

[0061] As described above, in this embodiment, in a cross section perpendicular to the direction in which the piezoelectric element 132 expands and contracts due to the application of a voltage, the center of gravity o2 of the holder 136 is set to be substantially the same as the center position o1 of the piezoelectric element 132. This makes it possible to prevent lateral shaking of the piezoelectric actuator 130 due to a shift in the center of gravity, and to suppress problems such as a decrease in heat transfer efficiency and peeling of joints.

[0062] <Modifications of Driver Support Member> Next, modified examples of the driver support member (holder) will be described with reference to Figures 9 and 10. Figure 9 is an explanatory diagram showing a modified example of the driver support member.

[0063] When the rim portion 136b covers the entire circumference of the piezoelectric element 132 as in the holder shown in Fig. 2(b), the rim portion 136b may be provided with a heat transfer material filling hole 136c for filling with a heat transfer material (e.g., thermally conductive grease) that forms the heat transfer layer 138. The heat transfer material filling hole 136c is provided on one surface or multiple surfaces of the rim portion 136b. This makes it possible to form the heat transfer layer 138 between the piezoelectric element 132 and each rim portion 136b by filling with thermally conductive grease from the heat transfer material filling hole 136c after the piezoelectric element 132 and the holder 136 are joined at the joint 137.

[0064] When the piezoelectric element 132 has a rectangular prism shape, the heat transfer material filling holes 136c may be provided in the rim portions 136b of each surface as shown in FIG. 9(a), or in the rim portions 136b of two opposing surfaces as shown in FIG. 9(b). The heat transfer material filling holes 136c may be provided not only in the rim portions 136b but also in the end portions 136a. When the heat transfer material filling holes 136c are provided in the end portions 136a, they are provided so as to be in communication with the surface of the piezoelectric element 132 at a position that does not interfere with the joint portion 137. Here, the heat transfer material filling holes 136c are an example of a "through hole".

[0065] As described above, in this embodiment, the end portion 136a or the rim portion 136b has the heat transfer material filling hole 136c that communicates with the surface of the piezoelectric element 132. This makes it possible to fill the heat transfer material that forms the heat transfer layer through the heat transfer material filling hole 136c even after the piezoelectric element 132 and the holder 136 are joined.

[0066] FIG. 10 is an explanatory diagram showing another modified example of the driver support member.

[0067] In the case where the rim portion 136b covers the entire circumference of the piezoelectric element 132 as in the holder shown in FIG. 2(b), the rim portion 136b may be provided so as to be separable in a direction intersecting with the direction in which the piezoelectric element 132 expands and contracts (Z direction). This allows the thermally conductive grease to be applied in a state in which the rim portion 136b is divided, making it easier to form the heat transfer layer 138 with a uniform thickness. Note that the division is not limited to the rim portion 136b, and the holder 136 including the end portion 136a may be provided so as to be separable as a whole. Here, being separable can be rephrased as meaning that the rim portion 136b of the holder 136 is configured by combining multiple members that can be combined in a direction intersecting with the direction in which the piezoelectric element 132 expands and contracts (Z direction). Here, being combineable means a configuration in which multiple parts can be integrated by a method such as joining, bonding, or fastening.

[0068] As described above, in this embodiment, the end portion 136a or the rim portion 136b is provided so as to be separable in a direction intersecting with the direction in which the piezoelectric element 132 expands and contracts (Z direction). In other words, in this embodiment, the end portion 136a or the rim portion 136b is formed by combining a plurality of members that can be combined in a direction intersecting with the direction in which the piezoelectric element 132 expands and contracts (Z direction). This makes it possible to apply the heat transfer material (e.g., thermally conductive grease) that forms the heat transfer layer 138 in a divided state, and makes it possible to make the thickness of the heat transfer layer 138 uniform.

[0069] The piezoelectric actuator 130 configured as described above can be applied to various industrial machines that require precise position control, minute supply control of fluid, etc. Examples include fine movement control of a precision stage or XY table of a semiconductor exposure device, marking position control of a laser marker on a PET bottle, etc., sensing position control in a detection device, etc. Other examples include flow rate control of fluid in semiconductor manufacturing equipment, supply control of liquid (ink, cleaning liquid, etc.) used in printing equipment, painting equipment, etc., flow rate control of medicines, etc. in medical equipment, injectors for fuel injection in automobile engines, etc. Below, an example will be described in which the above piezoelectric actuator is applied to a liquid ejection head that ejects liquid such as ink.

[0070] <Configuration of Liquid Ejection Head> Fig. 11 is a general configuration diagram showing an example of a liquid ejection head according to an embodiment, Fig. 11(a) is a schematic cross-sectional view of the liquid ejection head showing a state in which the nozzles are closed, and Fig. 11(b) is a schematic cross-sectional view of the liquid ejection head showing a state in which the nozzles are open.

[0071] The liquid ejection head 100 (hereinafter referred to as the head) comprises a housing 110 and a nozzle plate 101 attached to one end of the housing 110. Nozzles 102 for ejecting liquid are formed in the nozzle plate 101. Here, the nozzles 102 are an example of "ejection ports". The housing 110 comprises a liquid inlet 113 for feeding liquid into the head, a liquid chamber 114 for temporarily storing the liquid fed from the liquid inlet 113, and a liquid outlet 115 for feeding the liquid out of the head. The housing 110 also comprises a bearing 135 for supporting the needle valve 131 movably in the opening and closing directions of the nozzle 102.

[0072] The piezoelectric actuator 130 is housed in a space within the housing 110 provided above the bearing 135. The configuration of the piezoelectric actuator 130 is as described above, and therefore description thereof will be omitted here. A fixing member 118 is provided via an elastic member 133 to one end of the piezoelectric actuator 130, i.e., the end of the end portion 136a (the upper end in the figure). A needle valve 131 is provided via an elastic member 133 to the other end of the piezoelectric actuator 130, i.e., the end of the piezoelectric element 132 (the lower end in the figure).

[0073] The elastic member 133 includes a frame portion 133a formed to surround the piezoelectric actuator 130, a spring portion 133b provided on a part of the frame portion 133a, and contact portions 133c and 133d that contact both ends of the piezoelectric actuator 130. The piezoelectric actuator 130 is supported by the elastic member 133 by being sandwiched between the contact portions 133c and 133d due to the restoring force of the spring portion 133b as it tries to contract.

[0074] One end of the needle valve 131 is joined to the lower part (opposite the abutment part 133d) of the frame part 133a of the elastic member 133, and the other end of the needle valve 131 is arranged so as to be able to abut against the nozzle 102 formed in the nozzle plate 101.

[0075] Moreover, a fixed member 118 abuts against an upper portion (opposite side to the abutting portion 133c) of the frame portion 133a of the elastic member 133. This fixed member 118 is fixed to the housing 110, and serves as a fixed point so that the elastic member 133 cannot move upward due to the displacement (expansion and contraction) of the piezoelectric element 132.

[0076] As described above, the needle valve 131 and the piezoelectric element 132 are arranged coaxially, i.e., in series in the liquid discharge direction, via the elastic member 133. The elastic member 133 does not necessarily need to be formed as an integral member, and may be formed, for example, by connecting a frame portion 133a and a spring portion 133b prepared as separate members. It is also preferable to use a low-expansion metal such as stainless steel or Invar material for the elastic member 133. Here, the needle valve 131 is an example of a "valve body".

[0077] In the above configuration, when a predetermined drive voltage is applied to the piezoelectric element 132, the piezoelectric element 132 contracts by ΔL from the position shown in Fig. 11(a) to the position shown in Fig. 11(b). This causes the elastic member 133 to also deform in a contracting direction, and the needle valve 131 attached to the elastic member 133 moves in a direction forming a gap G with the nozzle plate 101. Due to the movement of the needle valve 131, the nozzle 102 changes from a closed state to an open state, and the fluid supplied under pressure to the liquid chamber 114 is discharged from the nozzle 102 as droplets D.

[0078] As described above, this embodiment is a liquid ejection head 100 including a nozzle 102 that ejects liquid, a needle valve 131 that is movable between a closed position for closing the nozzle 102 and an open position for opening the nozzle 102, and a piezoelectric actuator that moves the needle valve 131 between the closed position and the open position, the piezoelectric actuator being the above-mentioned piezoelectric actuator 130, and the other end of the piezoelectric element 132 in the direction in which it expands and contracts being connected to the needle valve 131. This reduces the positional fluctuation of the piezoelectric element 132 that depends on temperature, and therefore reduces the positional fluctuation of the needle valve 131, making it possible to provide a liquid ejection head that is capable of maintaining ejection performance.

[0079] Fig. 12 is a general configuration diagram showing another example of a liquid ejection head according to an embodiment, Fig. 12(a) is a schematic cross-sectional view of the liquid ejection head showing a state in which the nozzles are closed, and Fig. 12(b) is a schematic cross-sectional view of the liquid ejection head showing a state in which the nozzles are open.

[0080] This configuration example differs from the configuration of the head shown in Fig. 11 in that an inverse spring mechanism 134 as an example of a movement magnifying mechanism is provided between the needle valve 131 and the piezoelectric element 132. Therefore, the configuration and operation of the inverse spring mechanism 134 will be mainly described here, and members having the same configuration and function as those in the head of Fig. 11 will be given the same reference numerals and will not be described. Note that in this configuration example, a piezoelectric element 132 is used that has an expansion and contraction characteristic that expands toward the nozzle plate 101 side when a voltage is applied.

[0081] The inverse spring mechanism 134 is an elastic member formed by molding appropriately deformable rubber, soft resin, etc., or a thin metal plate, etc. The inverse spring mechanism 134 includes a deformation portion 134a, a fixed portion 134b, a guide portion 134c, and a bent side 134d.

[0082] The deformation portion 134a has a generally trapezoidal cross section formed so as to abut against the base end surface of the needle valve 131 (the upper end surface of the needle valve 131 in FIG. 12(a)). The fixed portion 134b is fixed to the deformation portion 134a and the inner wall surface of the housing 110. The guide portion 134c connects the fixed portion 134b and the piezoelectric element 132 via the elastic member 133. The bent side 134d connects the long side of the trapezoidal deformation portion 134a (corresponding to the lower base of the trapezoid) and the fixed portion 134b.

[0083] In the inverse spring mechanism 134 having the above-described structure, when a predetermined voltage is applied to the piezoelectric element 132 to expand the piezoelectric element 132, the expansion of the piezoelectric element 132 pushes the guide portion 134c toward the nozzle 102 (the direction of the arrow a in FIG. 12(b)). This pushing force draws the deformation portion 134a in a direction away from the nozzle 102 (the direction of the arrow b in FIG. 12(b)). In other words, the inverse spring mechanism 134 converts the expanding force of the piezoelectric element 132 into a force that draws in the needle valve 131, and transmits it to the needle valve 131.

[0084] In the head 100 according to this configuration example, when a voltage is applied to the piezoelectric element 132, the piezoelectric element 132 expands, and accordingly the needle valve 131 opens the nozzle 102, and a droplet D is ejected from the nozzle 102.

[0085] The head 100 equipped with the inverse spring mechanism 134 can obtain a large displacement with a small displacement of the piezoelectric element 132 compared to a head not equipped with the inverse spring mechanism. In other words, it has the characteristic that it can expand (amplify) the original displacement amount of the piezoelectric element 132. However, this characteristic means that the positional fluctuation of the needle valve 131 becomes large when the piezoelectric element 132 is thermally deformed.

[0086] For example, if the piezoelectric element 132 expands due to a temperature rise caused by self-heating or the like, the nozzle 102, which is normally closed, will be opened through the inverse spring mechanism 134, causing liquid to leak from the nozzle 102. Conversely, if the piezoelectric element 132 contracts, the needle valve 131 will be pushed further toward the nozzle 102 than its normal closed position, accelerating deterioration of the needle valve 131.

[0087] Therefore, by using a holder 136 having an end portion 136a having a linear expansion coefficient with an opposite sign to that of the piezoelectric element 132, it is possible to suppress the above-mentioned problems even when the temperature of the piezoelectric element 132 rises.

[0088] As described above, in this embodiment, between the piezoelectric element 132 and the needle valve 131, there is provided the inverse spring mechanism 134 which expands the amount of expansion and contraction of the piezoelectric element 132 to move the needle valve 131. This makes it possible to reduce problems particular to the inverse spring mechanism, such as incomplete closing of the nozzle and excessive contact of the needle valve with the nozzle.

[0089] <Control Unit Configuration> FIG. 13 is a block diagram showing an example of a control system for a liquid ejection head.

[0090] 13, the control unit 600 is electrically connected to the drive control unit 500 of the head 100, the liquid pressurizing mechanism 200, the head moving mechanism 300, and the like. The control unit 600 may, for example, control the overall operation of various systems and devices described below, and components other than those shown in FIG. 13 may be added as necessary.

[0091] The control unit 600 transmits, for example, an ink ejection period signal based on image data to the drive control unit 500. The control unit 600 receives status information and the like of the head 100 via the drive control unit 500. The control unit 600 also transmits a switching signal to the liquid pressurizing mechanism 200 for switching pressurization on and off. Furthermore, the control unit 600 transmits a movement signal to the head moving mechanism 300 for moving the head 100.

[0092] The drive control unit 500 includes an input unit 501, a drive voltage generation unit 502, an amplification unit 503, and an output unit 504. The input unit 501 receives an ink ejection periodic signal based on image data from the control unit 600. The drive voltage generation unit 502 generates a drive voltage for driving the piezoelectric element 132 of the head 100 in accordance with information such as the ink ejection periodic signal received by the input unit 501.

[0093] The amplifier 503 amplifies the drive voltage generated by the drive voltage generator 502, and outputs the amplified signal to the output unit 504. The output unit 504 applies a drive voltage to the piezoelectric element 132 based on the signal amplified by the amplifier 503.

[0094] The functions of the input unit 501, the drive voltage generating unit 502, the amplifying unit 503, the output unit 504, etc. can be realized by electric circuits, and some of these functions can also be realized by software. Furthermore, each of the above functions may be realized by multiple circuits or multiple pieces of software.

[0095] As described above, the drive control unit 500 generates a drive signal based on the ink ejection periodic signal received from the control unit 600, and uses the generated drive signal to drive the head 100. The head 100 opens and closes the nozzles 102 in response to the drive signal from the drive control unit 500, and ejects ink.

[0096] The liquid pressurizing mechanism 200 switches, for example, a compressor and an air regulator on and off based on a switching signal received from the control unit 600, and switches the ink sent to the liquid chamber 114 of the head 100 between a pressurized state and a non-pressurized state.

[0097] Based on a movement signal received from the control unit 600, the head movement mechanism 300 drives, for example, a drive device in a predetermined direction by a predetermined distance, to move the head 100 to a desired position.

[0098] Here, in the case of a head not equipped with a reverse spring mechanism, the needle valve 131 closes the nozzle 102 when the piezoelectric element 132 expands, and the needle valve 131 opens the nozzle 102 when the piezoelectric element 132 contracts, but this relationship is reversed in the case of a head equipped with a reverse spring mechanism 134. That is, in a head equipped with a reverse spring mechanism 134, the needle valve 131 opens the nozzle 102 when the piezoelectric element 132 expands, and the needle valve 131 closes the nozzle 102 when the piezoelectric element 132 contracts. Therefore, in a head equipped with a reverse spring mechanism 134, drive control is executed taking into account the fact that the relationship between the expansion and contraction of the piezoelectric element 132 and the opening and closing of the nozzle 102 is reversed.

[0099] The control unit 600 and the drive control unit 500 are not limited to being provided separately. For example, the control unit 600 may have the function of the drive control unit 500 and may be configured as a single control unit. Also, the drive control unit 500 and the head 100 may be unitized and configured as a head unit.

[0100] FIG. 14 is a block diagram illustrating an example of a hardware configuration of the control unit.

[0101] Each control unit 600, 500 includes a CPU (Central Processing Unit) 6001, 5001, a ROM (Read Only Memory) 6002, 5002, a RAM (Random Access Memory) 6003, 5003, an I / O port 6004, 5004, and a bus line 6005, 5005.

[0102] The CPU 6001, 5001 is an arithmetic unit that executes programs stored in the ROM 6002, 5002 to perform sequential, branch, iterative processing, and the like.

[0103] The ROM 6002, 5002 is a non-volatile storage device that stores the programs executed by the CPU 6001, 5001, etc.

[0104] The RAMs 6003 and 5003 are memories that function as work areas for the operations of the CPUs 6001 and 5001 .

[0105] The I / O ports 6004, 5004 are interfaces that input various command signals and data for operating various systems and devices, etc., described below, and output various signals, such as drive signals, to various drive mechanisms such as the liquid pressurizing mechanism 200 and the head moving mechanism 300.

[0106] The bus lines 6005, 5005 are address buses, data buses, etc. for electrically connecting the components such as the CPUs 6001, 5001.

[0107] <Applications of liquid ejection heads> Next, an application example of the liquid ejection head will be described below. Fig. 15 is a general configuration diagram showing an application example of the liquid ejection head.

[0108] 15 is configured as a head module 700 having a plurality of the above-mentioned heads 100. The head module 700 includes a plurality of heads 100 (eight in this application example) in a housing 710. The housing 710 has a supply port 711 that supplies liquid into the housing 710, a supply path 712 that connects the supply port 711 and a liquid inlet 713, and a liquid outlet 715 provided on the opposite side of the liquid inlet 713 with a liquid chamber 714 in between. The housing 710 also has a recovery port 717 that recovers liquid in the housing 710, and a recovery path 716 that connects the recovery port 717 and the liquid outlet 715.

[0109] 15, head 100 is illustrated as a head not equipped with reverse spring mechanism 134, but it is of course possible to use a head equipped with reverse spring mechanism 134. The basic configuration of head 100 is similar to that explained in FIG. 11, and in FIG. 15, corresponding elements are indicated by reference numerals in the 700 series.

[0110] The eight heads 100 are arranged in one-to-one correspondence with the eight nozzles 702 formed at equal intervals on a nozzle plate 701, and are installed so that the up-down direction in the figure corresponds to the opening and closing direction of a needle valve 731.

[0111] Furthermore, the liquid chamber 714 is provided between adjacent heads so that the liquid outlet 715 of the upstream head communicates with the liquid inlet 713 of the downstream head, and connects the supply path 712 with the recovery path 716. As a result, the liquid supplied under pressure from the supply port 711 into the housing 710 is sent to the liquid chamber 714 of each head 100 via the supply path 712. The liquid is pressurized when it is supplied into the housing 710 by, for example, a liquid pressurizing mechanism 200 shown in FIG.

[0112] The liquid flowing through the liquid chamber 714 of each head 100 is ejected as droplets from the nozzle 102 when the needle valve 731 is moved by the piezoelectric actuator 730 to the side that opens the nozzle 102. The liquid that is not ejected from the nozzle 102 passes through the recovery path 716 and is sent out from the housing 710 through the recovery port 717. The liquid sent out from the recovery port 717 is sent to a waste liquid tank or the like and disposed of. Alternatively, a circulation path that returns the liquid sent out from the recovery port 717 to the supply port 711 again may be provided, allowing the liquid to be reused.

[0113] In the head module 700 as well, by using the piezoelectric actuator 730 of the present invention, it is possible to provide a liquid ejection head that is capable of suppressing positional fluctuation of the needle valve 731 relative to the nozzle plate 701 (nozzle 702) and maintaining ejection performance.

[0114] In the head module 700, the specifications of the piezoelectric actuator 730 may be different for each head 100. In a configuration having a plurality of heads 100, such as the head module 700, it is conceivable that the heads disposed near the supply port 711 and the recovery port 717 will experience different temperature rises than the heads disposed in the center. In such cases, the holder specifications of the piezoelectric actuator 730, i.e., the material of the end and rim portions and the length of the end portions, may be changed for each head, and optimized for each head.

[0115] <Liquid application device> Hereinafter, a liquid applying device using the above-mentioned liquid ejection head will be described.

[0116] <Application example to car body painting system> As an example of the device for applying a liquid, an application example to a vehicle body painting system will be described with reference to Figures 16 and 17. Figure 16 is an explanatory diagram showing a first example of the device for applying a liquid according to an embodiment, and Figure 17 is an explanatory diagram showing a usage example of the first example of the device for applying a liquid.

[0117] The body painting system 810 includes at least one head 100, a camera 812 arranged near the head 100, an XY table 811 for moving the head 100 and the camera 812 in the X and Y directions, image editing software S for editing images captured by the camera 812, a monitor 610 for displaying the images to be edited, a control unit 600, etc.

[0118] The head 100 may not include the inverse spring mechanism 134, or may include the inverse spring mechanism 134. Moreover, instead of the head 100, a head module 700 shown in FIG.

[0119] The control unit 600 operates the XY table 811 and causes the head 100 to eject a liquid (eg, paint) based on a predetermined control program.

[0120] The vehicle body painting system 810 can apply paint discharged from a head 100 to an object U to which paint is to be applied. The head 100 discharges paint from a nozzle 102 toward a surface of the object U to which paint is to be applied. The paint discharged from the nozzle 102 is discharged in a direction approximately perpendicular to the XY plane. The distance between the nozzle 102 and the surface of the object U to which paint is to be applied is, for example, about 20 cm.

[0121] The XY table 811 has an X-axis 813 formed with a linear movement mechanism, and a Y-axis 814 that moves the X-axis 813 in the Y direction while holding the X-axis 813 with two arms. The head 100 and the camera 812 are attached to, for example, a head holding member. A shaft 815 is provided on the Y-axis 814. By holding this shaft 815 with a robot arm 816, the head 100 and the camera 812 can be freely positioned with respect to the object U to be treated.

[0122] For example, when the object U is a car, the robot arm 816 can be placed on the top of the object U as shown in Fig. 17(a) or on the side of the object U as shown in Fig. 17(b). The control unit 600 controls the operation of the robot arm 816 based on a predetermined program.

[0123] The camera 812 photographs a predetermined range on the surface of the object U to which the application is to be applied at constant minute intervals while moving in the XY directions together with the head 100. The camera 812 is, for example, a digital camera. In the camera 812, specifications such as a lens specification or a resolution capable of photographing a plurality of sub-divided images obtained by dividing the predetermined range of the surface to which the application is to be applied are appropriately selected. The photographing of the plurality of sub-divided images of the surface to which the application is to be applied by the camera 812 is performed continuously and automatically according to a program previously provided in the control unit 600.

[0124] As described above, the vehicle body painting system 810 is equipped with the head 100 according to this embodiment, which enables stable ejection of paint and allows paint to be applied to the object U with high precision.

[0125] <Example of application to printing devices> Next, as another example of the device for applying a liquid, an example of application to a printing device will be described with reference to Figures 18 and 19. Figure 18 is an explanatory diagram showing a second example of the device for applying a liquid according to an embodiment, and Figure 19 is a perspective view of a carriage portion of the device for applying a liquid of the second example.

[0126] 18 is installed facing an object U. The printing device 830 includes an X-axis rail 833, a Y-axis rail 834 intersecting with the X-axis rail 833, and a Z-axis rail 835 intersecting with the X-axis rail 833 and the Y-axis rail 834.

[0127] The Y-axis rail 834 holds the X-axis rail 833 so that the X-axis rail 833 can move in the Y direction (positive and negative sides). The X-axis rail 833 holds the Z-axis rail 835 so that the Z-axis rail 835 can move in the X direction (positive and negative sides). The Z-axis rail 835 holds the carriage 831 so that the carriage 831 can move in the Z direction (positive and negative sides).

[0128] The printing device 830 includes a first Z-direction drive unit 838 that moves the carriage 831 in the Z direction along the Z-axis rail 835, and an X-direction drive unit 836 that moves the Z-axis rail 835 in the X direction along the X-axis rail 833. The printing device 830 also includes a Y-direction drive unit 837 that moves the X-axis rail 833 in the Y direction along the Y-axis rail 834. The printing device 830 also includes a second Z-direction drive unit 839 that moves the head holder 832 in the Z direction relative to the carriage 831.

[0129] The printing device 830 configured as described above ejects ink from the head module 700 provided on the head holder 832 while moving the carriage 831 in the X, Y, and Z directions, and performs printing on the object U. Note that the movement of the carriage 831 and the head holder 832 in the Z direction does not necessarily mean that it is parallel to the Z direction, and may be an oblique movement as long as it includes at least a component in the Z direction.

[0130] In addition, although the surface shape of the object U to be treated is shown as a flat surface in the figure, the surface shape of the object U to be treated may be a surface that is close to vertical, such as the body of a car or truck, or the body of an aircraft, a surface with a large radius of curvature, or a surface with some unevenness.

[0131] FIG. 19 shows a carriage 831 mounted on the printing device 830 shown in FIG. 18, as viewed from the object U side.

[0132] The carriage 831 includes a head holder 832. The carriage 831 is also movable in the Z direction (positive and negative sides) along the Z-axis rail 835 by the power from the first Z-direction drive unit 838 described above.

[0133] The head holder 832 is movable in the Z direction (positive and negative sides) relative to the carriage 831 by power from the above-mentioned second Z-direction drive unit 839. The head holder 832 also includes a head fixing plate 832a for mounting the head module 700. In this application example, a configuration is exemplified in which six head modules 700 shown in Fig. 15 are mounted on the head fixing plate 832a, and the six head modules 700 are arranged in a stacked configuration.

[0134] Each head module 700 includes a plurality of nozzles 702. The type and number of colors of liquid (e.g., ink) used in the head modules 700 may be different for each head module, or may all be the same color. For example, if the printing device 830 is a device that uses a single color, the ink used in the six head modules 700 may be the same color. Also, the number of head modules 700 is not limited to six. It may be more than six, or it may be less than six.

[0135] The head module 700 is fixed to the head fixing plate 832a in a state in which the nozzle row (row of eight nozzles 702) of each head module intersects with the horizontal plane (XZ plane) and the arrangement direction of the multiple nozzles 702 is tilted with respect to the X axis. In this state, the nozzles 702 eject liquid in a direction intersecting with the direction of gravity (positive side of the Z direction).

[0136] As described above, the printing device 830 is equipped with a head module 700 having multiple heads 100 according to this embodiment, which enables stable ejection of ink and allows ink to be applied to the desired position on the object U with high precision.

[0137] <Application example to electrode manufacturing equipment> Next, as another example of the liquid applying device, an application example to an electrode manufacturing device will be described with reference to Figures 20 to 22. Figure 20 is an explanatory diagram showing a third example of the liquid applying device according to the embodiment, Figure 21 is an explanatory diagram showing another example of the liquid applying device of the third example, and Figure 22 is an explanatory diagram showing a modified example of the liquid applying device of the third example.

[0138] 20 is an apparatus for manufacturing negative electrodes used in electrochemical elements such as primary batteries, secondary batteries, capacitors, condensers, etc. The electrode manufacturing apparatus 850 includes a liquid ejection unit 852 including the head 100 or head module 700 described above, and ejects liquid onto an object (an electrode substrate for a negative electrode in this embodiment) U on a stage 851 using an inkjet method.

[0139] The head 100 and the head module 700 may use a head that does not include the inverse spring mechanism 134, or may use a head that includes the inverse spring mechanism 134. The liquid tank 853 contains the liquid composition D1 for forming the negative electrode mixture layer 855, and supplies the liquid composition D1 from the liquid tank 853 to the liquid discharge unit 852 via the tube 854.

[0140] Moreover, the electrode manufacturing apparatus 850 shown in FIG. 21 can also be used to manufacture negative electrodes for use in electrochemical devices.

[0141] In the electrode manufacturing apparatus 850, a belt-shaped object U (a negative electrode substrate in this embodiment) made of stainless steel, copper, or the like is wound around a cylindrical core, and loaded onto a delivery roller 857 and a take-up roller 859 with the surface on which the negative electrode composite layer 855 is to be formed facing up. The delivery roller 857 and the take-up roller 859 rotate counterclockwise, and the object U moves from right to left in the drawing.

[0142] The liquid tank 853 contains a liquid composition D1 for forming a negative electrode composite layer 855, and supplies the liquid composition D1 from the liquid tank 853 to the liquid discharge unit 852 via a tube 854. The liquid discharge unit 852 is installed above the object U to be treated and between a delivery roller 857 and a take-up roller 859. Furthermore, a plurality of the liquid discharge units 852 may be installed in a direction substantially parallel to or substantially perpendicular to the transport direction of the object U to be treated.

[0143] The delivery roller 857 and the take-up roller 859 transport the object U on which the liquid composition D1 is placed to a drying device 858. As a result, the liquid composition D1 on the object U is dried by the drying device 858 to become a negative electrode mixture layer 855, and a negative electrode 856 is formed in which the negative electrode mixture layer 855 is bonded to the electrode base for a negative electrode as the object U. Thereafter, the negative electrode 856 is cut to a desired size by punching or the like.

[0144] The drying device 858 is not particularly limited as long as it does not directly contact the liquid composition D1, and can be appropriately selected. For example, a resistance heater, an infrared heater, a fan heater, etc. can be mentioned. The drying device 858 may be configured to be installed either above or below the object U to be treated. Furthermore, a plurality of drying devices 858 may be installed.

[0145] In the above, an apparatus for manufacturing a negative electrode used in an electrochemical element has been described as an example, but it is of course possible to apply the present invention to an apparatus for manufacturing a positive electrode. When manufacturing a positive electrode, the object U is replaced from the negative electrode substrate to a positive electrode substrate, and the liquid composition D1 for forming the negative electrode mixture layer 855 is replaced with a liquid composition for forming a positive electrode mixture layer.

[0146] As described above, the electrode manufacturing apparatus 850 includes a liquid ejection unit 852 having the head 100 or the head module 700 according to this embodiment. As a result, the liquid composition can be stably ejected, and the liquid composition can be applied to a desired position on the object U with high accuracy.

[0147] 20 and 21, the liquid composition D1 is supplied from the liquid tank 853 to the liquid discharge unit 852 via the tube 854. However, the liquid composition D1 may be circulated through the liquid discharge unit 852.

[0148] 22, an external tank 860 is connected to a liquid tank 853 via a valve 861, and the liquid tank 853 is connected to a liquid discharge unit 852 via a valve 862. Furthermore, the liquid discharge unit 852 is connected to a pump 864 via a valve 863, and the pump 864 is connected to the liquid tank 853. In the above configuration, by controlling the flow of the liquid composition D1 using the pump 864 and the valves 862 and 863, the liquid composition D1 contained in the liquid tank 853 can be circulated within the electrode manufacturing apparatus 850.

[0149] In addition, by providing an external tank 860 and controlling a valve 861, when the amount of the dischargeable liquid composition D1 decreases, it is also possible to supply the liquid composition D1 from the external tank 860 to a liquid tank 853 of the electrode manufacturing apparatus 850. The negative electrode mixture layer 855 can be suitably used as a part of the configuration of an electrochemical element, for example. There are no particular limitations on the configuration other than the electrode mixture layer in the electrochemical element, and known configurations can be appropriately selected, for example, a positive electrode, a negative electrode, a separator, etc.

[0150] <Application example to a running robot> Next, as another example of the device for applying a liquid, an application example to a running robot will be described with reference to Fig. 23. Fig. 23 is an explanatory diagram showing a fourth example of the device for applying a liquid according to the embodiment.

[0151] 23 is an unmanned vehicle capable of traveling on a road surface, for example. The traveling robot 870 can move an object U (in this embodiment, a road surface such as a roadway or a sidewalk) by driving wheels 871. The traveling robot 870 includes a liquid ejection unit 872 including the head 100 or head module 700 described above, and supplies liquid (e.g., paint) contained in a liquid tank 873 to the liquid ejection unit 872 through a cable 874 using an inkjet method.

[0152] The head 100 and the head module 700 may use a head that does not include the inverse spring mechanism 134, or may use a head that includes the inverse spring mechanism 134. The traveling robot 870 ejects liquid from the liquid ejection unit 872 toward the object U, and applies the liquid to the coating portion P of the object U, thereby forming, for example, a crosswalk, a stop line, a center line, or the like on the road surface.

[0153] <Supplementary Information> In the present invention, a "liquid applying device" is a device that has a liquid ejection head and applies liquid by driving the liquid ejection head. The liquid applying device includes not only a device that can apply liquid to a receiving object, but also a device that ejects liquid into air or liquid.

[0154] This "liquid applying device" can also include means for supplying, transporting, and discharging the object to be applied, as well as other pre-processing devices, post-processing devices, etc. For example, "liquid applying devices" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to form a three-dimensional object (a three-dimensional model).

[0155] In addition, the term "liquid applying device" is not limited to devices that visualize meaningful images such as letters and figures by applying liquid. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0156] The above-mentioned "subject" means something to which the liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include recording media such as paper, recording paper, film, and cloth, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all things to which the liquid adheres.

[0157] The material of the "subject" may be any material to which the liquid can be attached even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, a current collector such as aluminum foil or copper foil, or an electrode having an active material layer formed on a current collector.

[0158] The "liquid" may have a viscosity and surface tension that allows it to be discharged from the head, and is not particularly limited. However, it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, an amino acid, a protein, or calcium, an edible material such as a natural dye, an active material or a solid electrolyte used as an electrode material, or an ink containing a conductive material or an insulating material. These may be used, for example, in inkjet inks, surface treatment liquids, liquids for forming components of electronic elements or light-emitting elements or electronic circuit resist patterns, material liquids for three-dimensional modeling, electrodes, electrochemical elements, paints for coating, and the like.

[0159] In addition, the "liquid applying device" may be a device in which the liquid ejection head and the object to be applied move relatively, but is not limited to this. Specific examples include a serial type device in which the liquid ejection head moves, a line type device in which the liquid ejection head does not move, etc.

[0160] Other examples of "liquid applying devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that sprays a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0161] Furthermore, the "liquid applying device" is not limited to a stationary device. The liquid applying device may be, for example, a robot equipped with a liquid ejection head and capable of moving by remote control or autonomous driving, and a mobile robot can be used to paint the exterior walls of buildings or road markings (crosswalks, stop lines, speed signs, etc.). In this case, buildings and roads are also included in the "object to which liquid is applied."

[0162] What has been described above is one example, and other embodiments, additions, modifications, deletions, and other changes can be made within the scope of what a person skilled in the art can imagine. As long as the effects of the present invention are achieved in any of the following aspects, they are included in the scope of the present invention.

[0163] [Aspect 1] Aspect 1 comprises a driver (e.g., piezoelectric element 132) that expands and contracts in one direction (e.g., Z direction) when a voltage is applied, and a driver support member (e.g., holder 136) having an abutment portion (e.g., end portion 136a) that abuts against one end of the driver in the expanding and contracting direction, and a contact portion (e.g., rim portion 136b) that extends from the abutment portion toward the other end of the driver and is arranged so as to be able to come into contact with the driver, wherein at least the abutment portion of the driver support member has a linear expansion coefficient with an opposite sign to that of the linear expansion coefficient of the driver.

[0164] [Aspect 2] Aspect 2 is characterized in that, in aspect 1, a heat transfer layer (e.g., heat transfer layer 138) is provided between the driving body and the contact portion, and the driving body and the contact portion are in contact with each other via the heat transfer layer.

[0165] [Aspect 3] A third aspect of the present invention is characterized in that in the first or second aspect, the heat transfer layer is provided so as to be operable in the direction in which the driving body expands and contracts.

[0166] [Aspect 4] A fourth aspect of the present invention is characterized in that in any one of the first to third aspects, the abutting portion and the contact portion are formed of different members.

[0167] [Aspect 5] A fifth aspect is any one of the first to third aspects, characterized in that the abutting portion and the contact portion are formed of a single member.

[0168] [Aspect 6] Aspect 6 is characterized in that, in any of aspects 1 to 5, the driving body has a cross-section (e.g., XY plane) perpendicular to the extension / contraction direction (e.g., Z direction) that has a polygonal outer shape having four or more sides, and the contact portion is configured to be able to contact the remaining sides excluding at least one of the four or more sides.

[0169] [Aspect 7] Aspect 7 is characterized in that, in any of aspects 1 to 5, the driving body has a cross-section (e.g., an XY plane) perpendicular to the extension / contraction direction (e.g., the Z direction) that has a polygonal shape with four or more sides or a circular shape, and the contact portion is arranged to be able to contact the entire circumference of the shape.

[0170] [Aspect 8] Aspect 8 is characterized in that, in aspect 6, in a cross section (e.g., an XY plane) perpendicular to the direction in which the driver expands and contracts (e.g., the Z direction), the center of gravity position of the driver support member (e.g., the holder center of gravity o2) is arranged to be approximately identical to the central position of the driver (e.g., the piezoelectric element center o1).

[0171] [Aspect 9] A ninth aspect is the same as the seventh aspect, characterized in that the abutting portion or the contact portion has a through hole (for example, a heat transfer material filling hole 136c) that communicates with the surface of the driver.

[0172] [Aspect 10] Aspect 10 is characterized in that, in aspect 7, the abutment portion or the contact portion is formed by combining a plurality of components that can be combined in a direction (e.g., the X direction or the Y direction) intersecting the extension / contraction direction (e.g., the Z direction) of the driving body.

[0173] [Aspect 11] Aspect 11 is a liquid ejection head (e.g., head 100) comprising an ejection port (e.g., nozzle 102) for ejecting liquid, a valve body (e.g., needle valve 131) movable between a closed position for closing the ejection port and an open position for opening the ejection port, and an actuator for moving the valve body between the closed position and the open position, wherein the actuator is an actuator (e.g., piezoelectric actuator 130) described in any one of claims 1 to 10, and the other end of the driving body (e.g., piezoelectric element 132) in the direction of expansion and contraction (e.g., Z direction) is connected to the valve body.

[0174] [Aspect 12] Aspect 12 is characterized in that, in aspect 11, there is provided a movement amplification mechanism (e.g., an inverse spring mechanism 134) between the driver and the valve body, which amplifies the amount of expansion and contraction of the driver to move the valve body.

[0175] [Aspect 13] Aspect 13 is a liquid-applying device (e.g., a body painting system 810, a printing device 830, an electrode manufacturing device 850, a traveling robot 870) characterized by comprising the liquid ejection head of aspect 11 and a drive control unit (e.g., drive control unit 500) that drives the drive body.

[0176] [Aspect 14] Aspect 14 is a liquid-applying device (e.g., a body painting system 810, a printing device 830, an electrode manufacturing device 850, a traveling robot 870) characterized by comprising the liquid ejection head of aspect 12 and a drive control unit (e.g., a drive control unit 500) that drives the drive body. [Explanation of symbols]

[0177] 100 Head (Example of liquid ejection head) 101 Nozzle plate 102 Nozzle 110 Cabinet 113 Liquid inlet 114 Liquid chamber 115 Liquid outlet 118 Fixing member 130 Piezoelectric actuator (an example of an actuator) 131 Needle valve (an example of a valve body) 132 Piezoelectric element (an example of a driver) 133 Elastic Members 133a Frame 133b Spring part 133c Contact part 133d Contact part 134 Reverse spring mechanism (an example of a movement magnification mechanism) 134a Deformation part 134b Fixed part 134c Guide section 134d Bent Edge 135 Bearings 136 Holder (an example of a driver support member) 136a End portion (an example of abutment portion) 136b Rim portion (an example of a contact portion) 136c Heat transfer material filling hole (an example of a through hole) 137 Joint 138 Heat Transfer Layer 500 Drive control unit (an example of a drive control unit) 600 Control section 700 Head Module 810 Painting system (an example of a device that applies liquid) 830 Printing device (an example of a device that applies liquid) 850 Electrode manufacturing equipment (an example of equipment for applying liquid) 870 Traveling robot (an example of a device that dispenses liquid) U Grantee

Claims

1. A driving body that expands and contracts in one direction when a voltage is applied; a driver support member having an abutment portion that abuts against one end of the driver in the extending and contracting direction, and a contact portion that extends from the abutment portion toward the other end of the driver and is provided so as to be able to come into contact with the driver; Equipped with An actuator, wherein at least the abutting portion of the driver support member has a linear expansion coefficient having an opposite sign to that of the driver.

2. 2. The actuator according to claim 1, further comprising a heat transfer layer between the driving body and the contact portion, the driving body and the contact portion being in contact with each other via the heat transfer layer.

3. 3. The actuator according to claim 2, wherein the heat transfer layer is provided so as to enable the driving body to move in the direction in which the driving body expands and contracts.

4. 2. The actuator according to claim 1, wherein the abutment portion and the contact portion are formed of different members.

5. 2. The actuator according to claim 1, wherein the abutment portion and the contact portion are formed from a single member.

6. The cross section of the driving body in a direction perpendicular to the direction of expansion and contraction has a polygonal shape having four or more sides, The contact portion is provided so as to be able to come into contact with the remaining sides excluding at least one side among the four or more sides.

2. The actuator according to claim 1.

7. the driving body has a cross section in a direction perpendicular to the direction of expansion and contraction that has a polygonal shape having four or more sides or a circular shape; The contact portion is provided so as to be able to come into contact with the entire periphery of the outer shape.

2. The actuator according to claim 1.

8. 7. The actuator according to claim 6, wherein the center of gravity of the driver support member is substantially the same as a center of the driver in a cross section perpendicular to the direction in which the driver expands and contracts.

9. 8. The actuator according to claim 7, wherein the abutment portion or the contact portion has a through hole communicating with a surface of the driver.

10. 8. The actuator according to claim 7, wherein the abutment portion or the contact portion is formed by combining a plurality of members that can be combined in a direction intersecting the direction in which the driver expands and contracts.

11. A discharge port for discharging liquid; a valve body that is movable between a closing position at which the discharge port is closed and an opening position at which the discharge port is opened; an actuator that moves the valve element between the closed position and the open position; A liquid ejection head comprising: The actuator comprises an actuator according to any one of claims 1 to 10, The other end of the driver in the direction in which it expands and contracts is connected to the valve body. A liquid ejection head comprising:

12. 12. The liquid ejection head according to claim 11, further comprising a movement enlarging mechanism between the driving body and the valve body, for enlarging an amount of expansion and contraction of the driving body to move the valve body.

13. The liquid ejection head according to claim 11, A drive control unit that drives the driving body; A liquid ejection device comprising:

14. A liquid ejection head according to claim 12; A drive control unit that drives the driving body; A liquid ejection device comprising:

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