Liquid dispensing head

Abstract

To suppress generation of unevenness in the viscosity of liquid in a flow channel member in a constitution in which an actuator member includes a trunk part.SOLUTION: A head 3 includes a flow channel member 21 having a plurality of individual flow channels formed therein, and an actuator member 22 having a plurality of actuator parts. The actuator member 22 includes a plurality of individual electrodes, a plurality of branch parts connecting the plurality of individual electrodes, and a trunk part connecting the plurality of branch parts and provided with a contact point with a COF. The head 3 further includes a cooling flow channel 60 which is independent from the plurality of individual flow channels and through which a cooling liquid flows. The cooling flow channel 60 has a first portion 61 overlapping with the trunk part in a Z direction.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a liquid ejection head that ejects a liquid such as ink.

Background Art

[0002] Patent Document 1 discloses a head (liquid ejection head) including a flow path member (flow path member) in which a plurality of pressure chambers are formed and an actuator member (actuator member) disposed on the surface of the flow path member. The actuator member includes a plurality of individual parts (individual electrodes) respectively corresponding to the plurality of pressure chambers, a plurality of branch parts connecting the plurality of individual parts, and a trunk part connecting the plurality of branch parts. A contact with a COF (power supply part) is provided on the trunk part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The trunk part is a part that supplies charges from the power supply part to the individual electrodes via the plurality of branch parts. Compared with the branch parts and the individual electrodes, a large amount of charges flow through the trunk part, and the amount of heat generation tends to increase. Therefore, the vicinity of the trunk part in the flow path member becomes locally high in temperature, and unevenness may occur in the viscosity of the liquid in the flow path member. As a result, the quality of an image formed by the liquid may deteriorate.

[0005] An object of the present invention is to provide a liquid ejection head capable of suppressing unevenness in the viscosity of a liquid in a flow path member in a configuration where an actuator member includes a trunk part.

Means for Solving the Problems

[0006] The liquid discharge head according to the present invention comprises a flow path member having a plurality of individual flow paths, each including a nozzle and a pressure chamber communicating with the nozzle, and an actuator member disposed on the surface of the flow path member and having a plurality of actuator portions that overlap each of the pressure chambers of the plurality of individual flow paths in a first direction perpendicular to the surface, wherein the actuator member includes a plurality of individual electrodes constituting the plurality of actuator portions, a plurality of branch portions connecting the plurality of individual electrodes, and a main body that connects the plurality of branch portions and is provided with a contact point for a power supply unit, and further comprises a cooling flow path through which a cooling liquid flows, independent of the plurality of individual flow paths, wherein the cooling flow path has a first portion that overlaps with the main body in the first direction. [Effects of the Invention]

[0007] According to the present invention, the portion of the flow channel member near the main body is cooled by the coolant flowing through the first portion of the cooling channel, thereby suppressing localized high temperatures in that portion. This makes it possible to suppress unevenness in the viscosity of the liquid within the flow channel member. [Brief explanation of the drawing]

[0008] [Figure 1] This is an overall configuration diagram of a printer including a print head according to one embodiment of the present invention. [Figure 2] Figure 1 is a plan view of the head. [Figure 3] This is an enlarged view of region III in Figure 2. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 3. [Figure 5] This is a cross-sectional view along the VV line in Figure 3. [Figure 6] This figure shows the operation of the actuator in a cross-sectional view. [Figure 7] This is a plan view showing the upper surface of the uppermost piezoelectric layer, one of the three piezoelectric layers that make up the actuator member in Figure 2. [Figure 8] This is a plan view showing the upper surface of the middle piezoelectric layer, one of the three piezoelectric layers that make up the actuator member in Figure 2. [Figure 9] It is a plan view showing the upper surface of the lowermost piezoelectric layer among the three piezoelectric layers constituting the actuator member of FIG. 2. [Figure 10] It is a plan view corresponding to FIG. 2 showing the flow path in the head. [Figure 11] It is a cross-sectional view taken along line XI-XI of FIG. 11. [Figure 12] It is an exploded perspective view of the flow path member, the actuator member, and the COF. [Figure 13] It is a cross-sectional view taken along line XIII-XIII of FIG. 12.

Mode for Carrying Out the Invention

[0009] In the following description, the Z direction is the vertical direction, and the X direction and the Y direction are the horizontal directions. Both the X direction and the Y direction are orthogonal to the Z direction. The X direction is orthogonal to the Y direction. The Z direction corresponds to the "first direction" of the present invention, the X direction corresponds to the "second direction" of the present invention, and the Y direction corresponds to the "third direction" of the present invention.

[0010] <Overall Configuration of Printer> First, referring to FIG. 1, the overall configuration of a printer 1 including a head 3 according to an embodiment of the present invention will be described.

[0011] The printer 1 includes a head 3, a carriage 2, and two pairs of conveyance rollers 4.

[0012] The carriage 2 is supported by two guide rails 5 extending in the Y direction and is movable in the Y direction along the guide rails 5.

[0013] The head 3 is of a serial type, is mounted on the carriage 2, and is movable in the Y direction together with the carriage 2. A plurality of nozzles 15 are opened on the lower surface of the head 3.

[0014] Two pairs of conveying rollers 4 are arranged sandwiching the carriage 2 in the X direction. By rotating while the conveying roller pairs 4 hold the sheet P, the sheet P is conveyed in the conveying direction along the X direction.

[0015] The control unit (not shown) of the printer 1 causes the ejection operation of ejecting ink from the nozzles 15 while moving the head 3 in the Y direction together with the carriage 2, and the conveying operation of conveying the sheet P by a predetermined amount in the conveying direction by the conveying roller pairs 4, to be performed alternately. Thereby, an image is recorded on the sheet P.

[0016] <Head> As shown in FIG. 2, the head 3 has a flow path member 21 and an actuator member 22. Both the flow path member 21 and the actuator member 22 are rectangular in shape with a length in the X direction longer than the length in the Y direction on a plane orthogonal to the Z direction.

[0017] <Flow path member> As shown in FIG. 4, the flow path member 21 is composed of four metal plates 31 to 34 laminated in the Z direction.

[0018] A plurality of pressure chambers 10 are formed in the plate 31. Communication passages 12 and 13 are formed in the plate 32 for each pressure chamber 10. The communication passages 12 and 13 overlap with one end and the other end in the Y direction of the corresponding pressure chamber 10 in the Z direction, respectively. Communication passages 14 are formed in the plate 33 for each communication passage 13. The communication passage 14 overlaps with the corresponding communication passage 13 in the Z direction. A plurality of nozzles 15 are formed in the plate 34. Each nozzle 15 overlaps with the communication passage 14 in the Z direction.

[0019] The flow path member 21 is formed with a plurality of individual flow paths 19 each including a nozzle 15 and a pressure chamber 10 communicating with the nozzle 15. As shown in FIG. 2, the plurality of individual flow paths 19 are arranged in the X direction and constitute 12 individual flow path rows 19R. The 12 individual flow path rows 19R are arranged side by side in the Y direction.

[0020] The flow channel member 21 further has 12 common flow channels 11 formed therein (see Figure 10). The common flow channels 11 are formed in the plate 33 (see Figure 4) and are provided for each individual flow channel row 19R (see Figure 2). Each of the 12 common flow channels 11 extends in the X direction and communicates with the multiple individual flow channels 19 that make up the corresponding individual flow channel row 19R. The 12 common flow channels 11 are aligned in the Y direction.

[0021] On the upper surface of plate 31 (surface 21a of flow channel member 21), an ink supply port 8, an ink return port 9, and a coolant communication port 6 are formed in the area where the actuator member 22 is not located (see Figure 2). Two ink supply ports 8, two ink return ports 9, and one coolant communication port 6 are arranged on one side and the other side in the X direction relative to the actuator member 22, respectively. The coolant communication port 6 is located in the center of the flow channel member 21 in the Y direction. The ink supply ports 8 and ink return ports 9 are arranged alternately in the Y direction.

[0022] The ink supply port 8 and the ink return port 9 are in communication with the ink tank (not shown). The ink supply port 8 and the ink return port 9 are positioned on either side of the three common flow channels 11 in the X direction, and each is in communication with the three common flow channels 11 (see Figure 10). Each common flow channel 11 has one end in communication with the ink supply port 8 and the other end in communication with the ink return port 9. Ink supplied from the ink tank to each ink supply port 8 is supplied to the three common flow channels 11 and returned to the ink tank from the ink return port 9.

[0023] Ink is supplied from each common channel 11 to multiple individual channels 19 that constitute the corresponding individual channel rows 19R. Then, as will be described later, when the actuator member 22 is driven, pressure is applied to the ink in the pressure chamber 10, and the ink is ejected from the nozzle 15 through the connecting passages 13 and 14.

[0024] The flow of coolant through the coolant communication port 6 will be described in detail later.

[0025] <Actuator component> As shown in Figure 4, the actuator member 22 is positioned on the surface 21a of the flow channel member 21. The actuator member 22 has a piezoelectric body 40 including three piezoelectric layers 41 to 43, and an electrode body 70 including three electrode layers 71 to 73 positioned on the upper surface of each piezoelectric layer 41 to 43.

[0026] The three piezoelectric layers 41-43 are each made of a piezoelectric material mainly composed of lead zirconate titanate, etc., and are stacked in the Z direction. A piezoelectric layer 42 is positioned between piezoelectric layer 43 and piezoelectric layer 41.

[0027] The piezoelectric layer 43 is positioned on the upper surface of the plate 31 (the surface 21a of the flow channel member 21) and covers all of the pressure chambers 10 formed in the plate 31.

[0028] Of the three electrode layers 71 to 73, electrode layer 71, which is located on the upper surface of the piezoelectric layer 41 (the surface of the piezoelectric layer 41 opposite to the piezoelectric layer 42 in the Z direction), includes, as shown in Figure 7, a plurality of driving electrodes 51, a dummy electrode 59, two high-potential sections 54, and two low-potential sections 55. Electrode layer 71 corresponds to the "first electrode layer" of the present invention.

[0029] As shown in Figure 3, the drive electrode 51 is positioned corresponding to the pressure chamber 10. The drive electrode 51 has a main portion 51a and a protruding portion 51b. The main portion 51a overlaps substantially the entire area of ​​the corresponding pressure chamber 10 in the Z direction. The protruding portion 51b protrudes from the main portion 51a in the Y direction and does not overlap the corresponding pressure chamber 10 in the Z direction. The protruding portion 51b is provided with contacts that are electrically connected to the COF (Chip On Film) 81 (see Figures 12 and 13). The driver IC 82 mounted on the COF 81 (see Figures 12 and 13), under the control of the control unit, supplies individual drive signals to each drive electrode 51 via the wiring of the COF 81, selectively applying either a high potential (VDD potential) or a low potential (GND potential). The high potential corresponds to the "first potential" of the present invention, the low potential corresponds to the "second potential" of the present invention, and the drive electrode 51 corresponds to the "first electrode" of the present invention. COF81 corresponds to the "power supply unit" of the present invention, and driver IC82 corresponds to the "drive circuit" of the present invention.

[0030] As shown in Figure 7, the multiple drive electrodes 51 are arranged in the X direction, forming multiple drive electrode rows 51R corresponding to each of the individual flow path rows 19R (see Figure 2). The multiple drive electrode rows 51R are arranged in the Y direction.

[0031] For each drive electrode row 51R, dummy electrodes 59 are provided on one side (upper part of Figure 7) and the other side (lower part of Figure 7) in the X direction. The dummy electrodes 59 have the same size and shape as the drive electrodes 51 belonging to the corresponding drive electrode row 51R in the plane perpendicular to the Z direction, and are arranged together with the drive electrodes 51 at equal intervals in the X direction. The dummy electrodes 59 are not electrically connected to the COF 81 and are not given any potential. By providing the dummy electrodes 59, the difference in the amount of shrinkage due to electrode formation between the drive electrode 51 in the center of the X direction and the drive electrode 51 at the end of the X direction in each drive electrode row 51R can be suppressed, and consequently, variations in the discharge amount from the multiple nozzles 15 corresponding to each drive electrode row 51R can be suppressed.

[0032] The two high-potential sections 54 are located on one side of the piezoelectric layer 41 in the X direction (upper side of Figure 7) at one end (left end in Figure 7) and the other end (right end in Figure 7) of the piezoelectric layer 41 in the Y direction, respectively. The two low-potential sections 55 are located on the other side of the piezoelectric layer 41 in the X direction (lower side of Figure 7) at one end (left end in Figure 7) and the other end (right end in Figure 7) of the piezoelectric layer 41 in the Y direction, respectively.

[0033] Each of the two high-potential sections 54 consists of multiple electrodes 54a arranged spaced apart from each other in the X direction. Each of the two low-potential sections 55 consists of multiple electrodes 55a arranged spaced apart from each other in the X direction. The electrodes 54a and 55a are approximately the same in size and shape in a plane perpendicular to the Z direction. The driver IC 82, under the control of the control unit, applies a high potential (VDD potential) to electrode 54a and a low potential (GND potential) to electrode 55a via the wiring of COF 81. Electrode 54a is held at a high potential, and electrode 55a is held at a low potential.

[0034] Of the three electrode layers 71 to 73, electrode layer 72, which is positioned on the upper surface of the piezoelectric layer 42 (between the piezoelectric layer 41 and the piezoelectric layer 42 in the Z direction), includes a high-potential electrode 52, two low-potential portions 56, two floating electrode portions 64, and a floating electrode portion 65, as shown in Figure 8. Electrode layer 72 corresponds to the "second electrode layer" of the present invention.

[0035] The high-potential electrode 52 includes a main stem 521, seven branch portions 523 branching from the main stem 521, and a plurality of individual electrodes 52a branching from each branch portion 523. The high-potential electrode 52 is maintained at a high potential (first potential) and corresponds to the "second electrode" of the present invention.

[0036] The main body 521 includes one extension 521a extending in the Y direction and two extensions 521b extending in the X direction. The extension 521a extends in the Y direction at one end of the piezoelectric layer 42 in the X direction (upper end in Figure 8). One of the two extensions 521b is connected to one end of the extension 521a in the Y direction (left end in Figure 8). The other of the two extensions 521b is connected to the other end of the extension 521a in the Y direction (right end in Figure 8). Each of the two extensions 521b extends from the connection point with the extension 521a to the other side in the X direction (lower side in Figure 8).

[0037] Each of the two extended portions 521b overlaps with the three electrodes 54a (see Figure 7) of the high-potential portion 54 in the Z direction. Each of the two extended portions 521b is electrically connected to the three electrodes 54a via through holes 41x (see Figure 7) formed in the piezoelectric layer 41, and receives a high potential from the electrodes 54a. That is, the two extended portions 521b are provided with contacts with the COF 81, which is the power supply portion. The high potential received by the two extended portions 521b is supplied to each individual electrode 52a via the branch portion 523.

[0038] The seven branches 523 each extend from the extension 521a to the other side in the X direction (the lower side in Figure 8) and are aligned in the Y direction. The width of each branch 523 is smaller than the width of the main trunk 521 (extension 521a, 521b).

[0039] Each individual electrode 52a overlaps the central portion of the pressure chamber 10 in the X direction with the portion in the Z direction, and has a portion that overlaps with the drive electrode 51 in the Z direction (see Figure 5). Multiple individual electrodes 52a are arranged in the X direction, forming multiple individual electrode rows 52R corresponding to each of the drive electrode row 51R (see Figure 7). Multiple individual electrode rows 52R are arranged in the Y direction.

[0040] The branch portion 523 connects multiple individual electrodes 52a that constitute each individual electrode row 52R. The extension portion 521a of the main body 521 connects seven branch portions 523. The extension portion 521a has seven branch portions A from which each of the seven branch portions 523 branches off.

[0041] The two low-potential sections 56 are located on the other side of the piezoelectric layer 42 in the X direction (lower side in Figure 8) at one end (left end in Figure 8) and the other end (right end in Figure 8) of the piezoelectric layer 42 in the Y direction. Each of the two low-potential sections 56 consists of two electrodes 56a and one electrode 56b, which are spaced apart from each other in the X direction.

[0042] The two floating electrode portions 64 are positioned between the extended portion 521b and the low-potential portion 56 in the X direction, at one end (left end in Figure 8) and the other end (right end in Figure 8) of the piezoelectric layer 42 in the Y direction. Each of the two floating electrode portions 64 is composed of multiple electrodes 64a arranged spaced apart from each other in the X direction.

[0043] The floating electrode portion 65 is located at the other end of the piezoelectric layer 42 in the X direction (the lower end in Figure 8). The floating electrode portion 65 is composed of a plurality of electrodes 65a arranged spaced apart from each other in the Y direction. The electrodes 65a have substantially the same size and shape in a plane perpendicular to the Z direction and are arranged at equal intervals in the Y direction.

[0044] The electrode 56a of the low-potential section 56 and the electrode 64a of the floating electrode section 64 are substantially the same in size and shape in a plane perpendicular to the Z direction, and are arranged at equal intervals in the X direction at one end (left end in Figure 8) and the other end (right end in Figure 8) of the piezoelectric layer 42 in the Y direction. On the other hand, the electrode 56b of the low-potential section 56 is longer in the X direction than the electrode 56a.

[0045] The two electrodes 56a overlap in the Z direction with the two electrodes 55a of the low-potential section 55 (see Figure 7). The two electrodes 56a are electrically connected to the two electrodes 55a via through holes 41y (see Figure 7) formed in the piezoelectric layer 41, and receive a low potential from the electrodes 55a.

[0046] Electrode 56b overlaps with one electrode 55a (see Figure 7) of the low-potential section 55 in the Z direction. Electrode 56b is electrically connected to the electrode 55a via a through-hole 41y (see Figure 7) formed in the piezoelectric layer 41, and receives a low potential from the electrode 55a.

[0047] The electrodes 64a and 65a of the floating electrode portions 64 and 65 are not electrically connected to any other electrode, and therefore no potential is applied to them.

[0048] Of the three electrode layers 71 to 73, electrode layer 73, which is located on the upper surface of piezoelectric layer 43 (the surface of piezoelectric layer 42 opposite to piezoelectric layer 41 in the Z direction), includes a low-potential electrode 53, a high-potential portion 57, and two floating electrode portions 66, as shown in Figure 9. Electrode layer 73 corresponds to the "third electrode layer" of the present invention.

[0049] The low-potential electrode 53 includes a main stem 531, six branch portions 533 branching from the main stem 531, and a plurality of individual electrodes 53a branching from each branch portion 533. The low-potential electrode 53 is maintained at a low potential (second potential) and corresponds to the "third electrode" of the present invention.

[0050] The main body 531 includes one extending portion 531a extending in the Y direction and two extending portions 531b, each extending in the X direction. The extending portion 531a extends in the Y direction at the other end of the piezoelectric layer 43 in the X direction (the lower end in Figure 9). One of the two extending portions 531b is connected to one end of the extending portion 531a in the Y direction (the left end in Figure 9). The other of the two extending portions 531b is connected to the other end of the extending portion 531a in the Y direction (the right end in Figure 9). Each of the two extending portions 531b extends to one side in the X direction (the upper side in Figure 9) from the connection point with the extending portion 531a.

[0051] The two extended portions 531b each overlap in the Z direction with the three electrodes 55a of the low-potential portion 55 (see Figure 7) and the three electrodes 56a and 56b of the low-potential portion 56 (see Figure 8). The two extended portions 531b are each electrically connected to the three electrodes 56a and 56b of the low-potential portion 56 via through holes 42y (see Figure 8) formed in the piezoelectric layer 42, and receive low potential from these electrodes 56a and 56b. That is, each of the two extended portions 531b is provided with a contact point with the COF 81, which is the power supply portion. The low potential received by the two extended portions 531b is supplied to each individual electrode 53a via the branch portion 533.

[0052] Each of the six branches 533 extends from the main stem 531a to one side in the X direction (upper side in Figure 9) and is aligned in the Y direction. The width of each branch 533 is smaller than the width of the main stem 531 (main stems 531a, 531b).

[0053] Of the multiple individual electrodes 53a, with the exception of the individual electrodes 53a located at one end and the other end in the X direction, each individual electrode 53a straddles two pressure chambers 10 adjacent to each other in the X direction and has a portion that overlaps with the two pressure chambers 10 in the Z direction (see Figure 5). The individual electrodes 53a located at one end and the other end in the X direction have a portion that overlaps with one pressure chamber 10 in the Z direction. In addition, each individual electrode 53a has a portion that overlaps with the drive electrode 51 in the Z direction. The multiple individual electrodes 53a are arranged in the X direction and constitute multiple individual electrode rows 53R corresponding to each of the drive electrode row 51R (see Figure 7). The multiple individual electrode rows 53R are arranged in the Y direction.

[0054] The branch portion 523 connects multiple individual electrodes 53a that constitute each individual electrode row 53R. The extension portion 531a of the main body 531 connects six branch portions 533. The extension portion 531a has six branch portions B from which each of the six branch portions 533 branches off.

[0055] The high-potential section 57 includes one first portion 57a ​​extending in the Y direction and two second portions 57b, each extending in the X direction. The first portion 57a ​​extends in the Y direction at one end of the piezoelectric layer 43 in the X direction (upper end in Figure 9). One of the two second portions 57b is connected to one end of the first portion 57a ​​in the Y direction (left end in Figure 9). The other of the two second portions 57b is connected to the other end of the first portion 57a ​​in the Y direction (right end in Figure 9). Each of the two second portions 57b extends from the connection point with the first portion 57a ​​to the other side in the X direction (lower side in Figure 9).

[0056] The two second portions 57b each overlap in the Z direction with the three electrodes 54a of the high-potential portion 54 (see Figure 7) and the respective extended portions 521b of the high-potential electrode 52 (see Figure 8). The two second portions 57b are each electrically connected to the extended portions 521b via through holes 42x (see Figure 8) formed in the piezoelectric layer 42, and receive a high potential from the extended portions 521b.

[0057] The two floating electrode portions 66 are positioned between the second portion 57b and the extended portion 531b in the X direction, at one end (left end in Figure 9) and the other end (right end in Figure 9) of the piezoelectric layer 43 in the Y direction. Each of the two floating electrode portions 66 is composed of multiple electrodes 66a arranged spaced apart from each other in the X direction. The electrodes 66a have substantially the same size and shape in a plane perpendicular to the Z direction and are arranged at equal intervals in the X direction.

[0058] Each electrode 66a of the floating electrode portion 66 is not electrically connected to any other electrode, and therefore no potential is applied to it.

[0059] <Actuator section> As shown in Figure 5, the portion of the piezoelectric layer 41 sandwiched between the drive electrode 51 and the individual electrodes 52a of the high-potential electrode 52 in the Z direction is called the first active portion 91. The portion of the piezoelectric layers 42 and 43 sandwiched between the drive electrode 51 and the individual electrodes 53a of the low-potential electrode 53 in the Z direction is called the second active portion 92. The first active portion 91 is mainly polarized upward, and the second active portion 92 is mainly polarized downward. The actuator member 22 has an actuator portion 90 for each pressure chamber 10, which consists of one first active portion 91 and two second active portions 92. In each actuator portion 90, the two second active portions 92 are separated from each other in the X direction and sandwich the first active portion 91. The X direction corresponds to the "orthogonal direction" of the present invention.

[0060] Now, referring to Figure 6, the operation of the actuator unit 90 corresponding to a nozzle 15 when ink is ejected from that nozzle 15 will be explained.

[0061] Before the printer 100 starts recording, a low potential (GND potential) is applied to each drive electrode 51, as shown in Figure 6(a). At this time, the potential difference between the drive electrode 51 and the high-potential electrode 52 generates an upward electric field equal to its polarization direction in the first active part 91, causing the first active part 91 to contract in the planar direction (along the X and Y directions). As a result, the portion of the laminate consisting of piezoelectric layers 41-43 that overlaps with the pressure chamber 10 in the Z direction is bent so as to become convex toward the pressure chamber 10 (downward). At this time, the volume of the pressure chamber 10 is smaller compared to when the laminate is flat.

[0062] When printer 1 starts recording and ejects ink from a nozzle 15, first, as shown in Figure 6(b), the potential of the drive electrode 51 corresponding to the nozzle 15 is switched from a low potential (GND potential) to a high potential (VDD potential). At this time, the contraction of the first active part 91 is eliminated as the potential difference between the drive electrode 51 and the high-potential electrode 52 disappears. On the other hand, a potential difference is created between the drive electrode 51 and the low-potential electrode 53, generating a downward electric field equal to its polarization direction in the second active part 92, causing the second active part 92 to contract in the planar direction. However, the second active part 92 has the function of suppressing crosstalk (a phenomenon in which pressure fluctuations due to the deformation of the actuator part 90 in a certain pressure chamber 10 are transmitted to another pressure chamber 10 adjacent to the pressure chamber 10 in the X direction), and therefore contributes almost nothing to the deformation of the actuator part 90. In other words, at this time, the laminate does not bend so that the part overlapping with the pressure chamber 10 in the Z direction becomes convex (upward) away from the pressure chamber 10, but remains flat. As a result, the volume of the pressure chamber 10 becomes larger than that shown in Figure 6(a).

[0063] Subsequently, as shown in Figure 6(a), the potential of the drive electrode 51 corresponding to the nozzle 15 is switched from a high potential (VDD potential) to a low potential (GND potential). At this time, the potential difference between the drive electrode 51 and the low-potential electrode 53 disappears, and the contraction of the second active part 92 is relieved. On the other hand, the potential difference between the drive electrode 51 and the high-potential electrode 52 creates an upward electric field equal to its polarization direction in the first active part 91, causing the first active part 91 to contract in the planar direction. As a result, the portion of the laminate that overlaps with the pressure chamber 10 in the Z direction bends so that it becomes convex toward the pressure chamber 10 (downward). At this time, the volume of the pressure chamber 10 decreases significantly, so that a large pressure is applied to the ink in the pressure chamber 10, and ink is ejected from the nozzle 15.

[0064] <Cooling channel> In addition to the ink channels, which include individual channels 19 and a common channel 11, the flow channel member 21 also has a cooling channel 60 (see Figures 10, 11, and 13) through which a cooling liquid (e.g., water) flows. The cooling channel 60 is independent of the ink channels and is in communication with a cooling liquid tank (not shown).

[0065] As shown in Figure 10, the cooling channel 60 has two U-shaped channels 6X formed along the outer circumference of the actuator member 22. Each of the two U-shaped channels 6X consists of one first portion 61 extending in the Y direction and two portions 63 extending in the X direction, and is arranged symmetrically with respect to the center of the channel member 21 in the X direction.

[0066] Two coolant communication ports 6 are provided on the outside in the X direction relative to the two U-shaped flow channels 6X. The first portion 61 of each U-shaped flow channel 6X and the coolant communication ports 6 are connected via a connecting portion 69.

[0067] Of the two U-shaped channels 6X, the first portion 61 of the U-shaped channel 6X located on one side in the X direction (upper side in Figure 10) overlaps with the extended portion 521a of the main body 521 of the high-potential electrode 52 (see Figure 8) in the Z direction and extends across seven branch sections A. Of the two U-shaped channels 6X, the first portion 61 of the U-shaped channel 6X located on the other side in the X direction (lower side in Figure 10) overlaps with the extended portion 531a of the main body 531 of the low-potential electrode 53 (see Figure 9) in the Z direction and extends across six branch sections B.

[0068] In the U-shaped flow channel 6X, part 63 is connected to one end and the other end of the first part 61 in the Y direction. Part 63 extends from the first part 61 toward the center of the flow channel member 21 in the X direction and has one end connected to the first part 61 and the other end opposite to the first part 61.

[0069] In the U-shaped flow path 6X, an inlet 60x is provided at the other end of one of the two sections 63, and an outlet 60y is provided at the other end of the other section 63. The inlet 60x and the outlet 60y are in communication with a coolant tank. In the U-shaped flow path 6X, the coolant flowing in from the inlet 60x flows through one of the two sections 63, then through the first section 61, then through the other section 63, and flows out from the outlet 60y.

[0070] As shown in Figure 11, the U-shaped channel 6X is formed in the plates 31 and 32 of the channel member 21. The portions 61 and 63 of the U-shaped channel 6X are formed by recesses formed by half-etching or the like on the lower surface of plate 31 and the upper surface of plate 32, respectively.

[0071] The cooling channel 60 has portions 61, 63, and 69 formed on the channel member 21 (see Figures 10 and 11), as well as portions 62 and 68 formed on the heat sink 83 and the intermediate member 88 (see Figure 13).

[0072] As shown in Figures 12 and 13, the COF81 has a central portion 81a positioned on the upper surface of the actuator member 22, and two lead portions 81b extending upward from both ends of the central portion 81a in the X direction. A driver IC 82 is mounted on each of the two lead portions 81b.

[0073] As shown in Figure 13, the COF81 is positioned along the outer surface of the holding member 80. The holding member 80 has the function of holding the orientation of the COF81 and is positioned on the upper surface of the central portion 81a. The pull-out portion 81b is positioned on the upper surface of the holding member 80. In the Z direction, the central portion 81a of the COF81 and the actuator member 22 are positioned between the holding member 80 and the flow path member 21.

[0074] The heatsink 83 is positioned on the top surface of the two driver ICs 82 and has the function of dissipating heat from the driver ICs 82. The intermediate member 88 is positioned between the heatsink 83 and the flow channel member 21.

[0075] A second portion 62 of the cooling channel 60 is formed in the heat sink 83. A portion 68 of the cooling channel 60 is formed in the intermediate member 88. The second portion 62 extends in the X direction and overlaps with the driver IC 82 in the Z direction. The portion 68 extends downward from one end and the other end of the second portion 62 in the X direction and is connected to the coolant communication port 6.

[0076] An inlet 60a and an outlet 60b communicating with a coolant tank are formed on the upper surface of the heat sink 83. Coolant flowing in from the inlet 60a flows through the second section 62 and flows out from the outlet 60b. Coolant flowing through the second section 62 flows through section 68 and into the U-shaped flow path 6X in the flow path member 21 from the coolant communication port 6.

[0077] <Effects of this embodiment> As described above, according to this embodiment, the cooling channel 60 has a first portion 61 that overlaps with the main body 521 (extended portion 521a) or the main body 531 (extended portion 531a) in the Z direction (see Figures 8 to 10). The cooling liquid flowing through the first portion 61 cools the portion of the channel member 21 near the main body 521 (extended portion 521a) or the main body 531 (extended portion 531a), thereby suppressing localized high temperatures in that portion. This suppresses unevenness in the viscosity of the ink within the channel member 21. Furthermore, since the cooling channel 60 is independent of the individual channels 19, the flow velocity of the cooling liquid can be controlled separately from the flow velocity of the ink flowing through the individual channels 19, and it is possible to increase the flow velocity to enhance the cooling effect.

[0078] The first section 61 extends across multiple branch sections A and B (see Figures 8 to 10). In this case, the configuration of the cooling channel 60 can be simplified compared to the case where the first section 61 is provided for each branch section A and B.

[0079] At least a portion of the first part 61 is formed on the plate 31 in which the pressure chamber 10 is formed (see Figure 11). In this case, by using the plate 31 in which the pressure chamber 10 is formed to form the cooling channel 60, it is not necessary to prepare a large number of plates for forming the cooling channel 60, thereby simplifying the configuration of the head 3 and reducing costs.

[0080] The width of the main stems 521 and 531 is greater than the width of the branches 523 and 533 (see Figures 8 and 9). The main stems 521 and 531 need to have sufficient cross-sectional area for charge supply. To ensure sufficient cross-sectional area, it is conceivable to increase the thickness and / or width, but increasing the thickness makes warping due to thermal shrinkage during electrode firing more likely. Therefore, from the viewpoint of suppressing warping, it is preferable to increase the width. However, if the width of the main stems 521 and 531 is increased, problems due to heat generation in the main stems 521 and 531 become more pronounced. By applying the present invention in such cases, the effects of the present invention can be effectively obtained.

[0081] The actuator unit 90 has a first active unit 91 and two second active units 92 (see Figure 6). In this case, when pressure fluctuations due to the deformation of the first active unit 91 are transmitted to the adjacent pressure chamber 10, they are canceled out by the deformation of the second active units 92, thereby effectively suppressing crosstalk.

[0082] The cooling channel 60 further has a second portion 62 that overlaps with the driver IC 82 in the Z direction (see Figure 13). In this case, not only the channel member 21 but also the driver IC 82 can be cooled. The driver IC 82 and the channel member 21 are thermally coupled, and by cooling the driver IC 82, unevenness in the viscosity of the ink in the channel member 21 can be further suppressed.

[0083] Multiple individual electrode rows 52R, 53R are provided, each consisting of multiple individual electrodes 52a, 53a arranged in the X direction (see Figures 8 and 9). The multiple individual electrode rows 52R, 53R are aligned in the Y direction. The branch portions 523, 533 extend in the X direction and are aligned in the Y direction to correspond to the individual electrode rows 52R, 53R. The extended portions 521a, 531a of the main body 521, 531 extend in the Y direction. The first portion 61 of the cooling channel 60 extends in the Y direction to correspond to the extended portions 521a, 531a and overlaps with the extended portions 521a, 531a in the Z direction (see Figure 10). In this case, an efficient configuration that matches the arrangement of the individual electrodes 52a, 53a can be realized.

[0084] <Variation> Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various design modifications are possible as long as they are within the scope of the claims.

[0085] The cooling channel is not limited to being located below the main body, but may also be located above the main body.

[0086] In the embodiment described above, the cooling channel is composed of a recess formed in the plate (see Figure 11), but it is not limited to this and may be composed of a through hole.

[0087] The first and second parts of the cooling channel do not need to be in communication with each other. Furthermore, the cooling channel does not need to have a second part.

[0088] The first potential is not limited to being high potential and the second potential to being low potential; the opposite may also be true (i.e., the first potential is low potential and the second potential is high potential). In this case, the high-potential electrode 52 may be located in the bottom layer and the low-potential electrode 53 in the intermediate layer.

[0089] In the above embodiment, there are three piezoelectric layers constituting the actuator member, but there may be two or four or more. For example, in the above embodiment (see Figure 4), a diaphragm made of stainless steel or the like may be provided instead of the piezoelectric layer 43. Alternatively, in the above embodiment (see Figure 4), another piezoelectric layer may be placed between the piezoelectric layer 43 of the actuator member 22 and the plate 31 of the flow channel member 21.

[0090] The present invention is not limited to printers, but can also be applied to facsimile machines, copiers, multifunction devices, etc. Furthermore, the present invention can also be applied to liquid dispensing devices used for purposes other than image recording (for example, liquid dispensing devices that dispense conductive liquid onto a substrate to form conductive patterns). [Explanation of Symbols]

[0091] 3 heads (liquid dispensing heads) 10 Pressure chamber 15 nozzles 19 Individual channel 21 Flow channel member 21a surface 22 Actuator component 31 Plates 40 Piezoelectric element 41-43 Piezoelectric layer 51 Driving electrode (first electrode) 52 High potential electrode (second electrode) 52a Individual electrode 52R individual electrode row 521 Executive 521a Extension 523 Branch 53 Low potential electrode (3rd electrode) 53a Individual electrode 53R Individual electrode array 531 Executive 531a Extension 533 Branches 60 Cooling channel 61 Part 1 62 Part 2 70 Electrode body 71 Electrode layer (first electrode layer) 72 Electrode layer (second electrode layer) 73 Electrode layer (3rd electrode layer) 81 COF (Power Supply Section) 82 Driver IC (Driver Circuit) 90 Actuator section 91 1st active part 92 2nd active part A, B branching point

Claims

1. A flow channel member having a plurality of individual flow channels formed therein, each including a nozzle and a pressure chamber communicating with the nozzle, The actuator member comprises an actuator member disposed on the surface of the flow channel member and having a plurality of actuator portions that overlap each of the pressure chambers of the plurality of individual flow channels in a first direction perpendicular to the surface, The actuator member includes a plurality of individual electrodes constituting the plurality of actuator parts, a plurality of branch parts connecting the plurality of individual electrodes, and a main body connecting the plurality of branch parts and having a contact point with the power supply part. The system further comprises a cooling channel through which coolant flows, independent of the aforementioned plurality of individual channels, The liquid discharge head is characterized in that the cooling channel has a first portion that overlaps with the main body in the first direction.

2. The aforementioned trunk has multiple branching points from which each of the multiple branching points branches, The liquid dispensing head according to claim 1, characterized in that the first portion extends across the plurality of branching portions.

3. The flow channel member has a plate in which the pressure chamber is formed, The liquid dispensing head according to claim 1, characterized in that at least a portion of the first part is formed on the plate.

4. The liquid dispensing head according to claim 1, characterized in that the width of the trunk is greater than the width of the branch.

5. The actuator member is A piezoelectric body comprising a plurality of piezoelectric layers stacked in the first direction, The electrode body includes a first electrode layer, a second electrode layer separated from the first electrode layer in the first direction, and a third electrode layer separated from the first electrode layer in the first direction. The first electrode layer comprises a plurality of first electrodes to which a first potential and a second potential different from the first potential are selectively applied, and includes a plurality of first electrodes that overlap each of the pressure chambers of the plurality of individual flow channels in the first direction. The second electrode layer includes a second electrode that is maintained at the first potential. The third electrode layer includes a third electrode that is maintained at the second potential. The piezoelectric material has a first active portion sandwiched between the first electrode and the second electrode in the first direction, and two second active portions sandwiched between the first electrode and the third electrode in the first direction, wherein the two second active portions are separated from each other in an orthogonal direction perpendicular to the first direction, sandwiching the first active portion. The liquid dispensing head according to claim 1, characterized in that at least one of the second electrode and the third electrode has the plurality of individual electrodes, the plurality of branches, and the main trunk.

6. The system further includes a drive circuit that supplies drive signals to the plurality of actuator units, The liquid discharge head according to claim 1, characterized in that the cooling channel further has a second portion that overlaps with the drive circuit in the first direction.

7. The device comprises a plurality of individual electrode rows, each composed of a plurality of individual electrodes arranged in a second direction perpendicular to the first direction, The plurality of individual electrode rows are arranged in a third direction that is perpendicular to the first direction and intersects the second direction. The plurality of branches each extend in the second direction and are aligned in the third direction, The aforementioned section has an extended portion that extends in the third direction, The liquid dispensing head according to any one of claims 1 to 6, characterized in that the first portion extends in the third direction and overlaps with the extended portion in the first direction.

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