JP2019177559A - Liquid discharge head - Google Patents

Abstract

To suppress decrease in a deformation amount of an actuator part caused by positional deviation between a flow passage unit and a piezoelectric actuator.SOLUTION: A piezoelectric actuator 22 includes an actuator part 60 structured of one first active part 61 and two second active parts 62, 63 for each pressure chamber 10. In a cross section along an X direction and a Z direction passing the pressure chamber 10, the first active part 61, and the second active parts 62, 63 of each actuator part 60, a separation distance (d4+d5) between the second active part 62 and the second active part 63 in the X direction is longer than a length D in the X direction of the pressure chamber 10.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a liquid discharge head including a flow path unit and a piezoelectric actuator stacked on the flow path unit.

  In FIG. 8 of Patent Document 1, a flow path unit having a discharge surface parallel to the X direction (first direction) and the Y direction (second direction) is stacked on the flow path unit in the Z direction (third direction). A liquid discharge head having a piezoelectric actuator is shown. The piezoelectric actuator includes a first active portion that overlaps with the pressure chamber of the flow path unit in the Z direction, and two second active portions that are separated from each other in the X direction. In FIG. 8 of Patent Document 1, in the cross section along the X direction and the Z direction passing through the pressure chamber, the first active portion, and the two second active portions, the separation distance in the X direction of the two second active portions is the pressure. It is the same as the length of the chamber in the X direction.

JP 2009-096173 A

  When the piezoelectric actuator is stacked on the flow path unit, if an X-direction misalignment occurs between the flow path unit and the piezoelectric actuator, the actuator section composed of the first active section and the two second active sections The amount of deformation can be reduced as compared with the case where there is no positional deviation. In the configuration of FIG. 8 of Patent Document 1, in the cross section along the X direction and the Z direction passing through the pressure chamber, the first active part, and the two second active parts, the separation distance in the X direction of the two second active parts is Since it is the same as the length of the pressure chamber in the X direction, as is clear from the analysis result described later, the deformation amount of the actuator portion is greatly reduced due to the positional deviation between the flow path unit and the piezoelectric actuator.

  An object of the present invention is to provide a liquid discharge head capable of suppressing a decrease in deformation amount of an actuator portion due to a positional deviation between a flow path unit and a piezoelectric actuator.

  A liquid discharge head according to a first aspect of the present invention has a discharge surface that is a discharge surface parallel to a first direction and a second direction orthogonal to the first direction and that defines a discharge port, A flow path unit in which a pressure chamber communicating with the discharge port is formed; and a piezoelectric actuator stacked on the flow path unit in a third direction orthogonal to the discharge surface. Piezoelectric material having a plurality of piezoelectric layers stacked in three directions, a first electrode, a second electrode spaced from the first electrode in the third direction, and spaced from the first electrode in the third direction The piezoelectric body is a first portion sandwiched between the first electrode and the second electrode in the third direction and overlaps the pressure chamber in the third direction A first portion having the third portion A second portion sandwiched between the first electrode and the third electrode in the direction, and a third portion sandwiched between the first electrode and the third electrode in the third direction, the first portion A third portion spaced apart from the second portion in the direction, and the first portion has a portion disposed between the second portion and the third portion in the first direction; In the cross section along the first direction and the third direction passing through the pressure chamber, the first portion, the second portion, and the third portion, the second portion and the third portion in the first direction, The separation distance is longer than the length of the pressure chamber in the first direction.

  A liquid discharge head according to a second aspect of the present invention has a discharge surface that is a discharge surface parallel to a first direction and a second direction orthogonal to the first direction, and is a surface that defines a discharge port, A flow path unit in which a pressure chamber communicating with the discharge port is formed; and a piezoelectric actuator stacked on the flow path unit in a third direction orthogonal to the discharge surface. Piezoelectric material having a plurality of piezoelectric layers stacked in three directions, a first electrode, a second electrode spaced from the first electrode in the third direction, and spaced from the first electrode in the third direction The piezoelectric body is a first portion sandwiched between the first electrode and the second electrode in the third direction and overlaps the pressure chamber in the third direction A first portion having the third portion A second portion sandwiched between the first electrode and the third electrode in the direction, and a third portion sandwiched between the first electrode and the third electrode in the third direction, the first portion A third portion spaced apart from the second portion in the direction, and the first portion has a portion disposed between the second portion and the third portion in the first direction; The piezoelectric actuator has one end in the first direction and the other end in the first direction, and the pressure chamber has one end in the first direction and the other end in the first direction. The other end of the pressure chamber is located between the one end of the pressure chamber and the other end of the piezoelectric actuator in the first direction, and the second portion is one end of the first direction. And the other end in the first direction, and the other end of the second portion is in the first direction. , Located between the one end of the second portion and the other end of the piezoelectric actuator, the other end of the second portion and the one end of the pressure chamber in the first direction of the piezoelectric actuator. The distance in the first direction from the other end of the second part to the center of the first part is located between the one end and the center of the first part in the first direction. Longer than half of the distance in the first direction from the one end to the other end of the pressure chamber.

  According to a first aspect of the present invention, in the cross section along the first direction and the third direction passing through the pressure chamber, the first portion, the second portion, and the third portion, the second portion and the third portion in the first direction, Satisfies the requirement that the separation distance is longer than the length of the pressure chamber in the first direction. According to a second aspect of the present invention, “the distance in the first direction from the other end of the second part to the center of the first part is more than half of the distance in the first direction from one end of the pressure chamber to the other end of the pressure chamber. Satisfy the requirement of “long”. In the configuration satisfying the requirements of the first aspect, when a displacement in the first direction occurs between the flow path unit and the piezoelectric actuator, the amount of deformation of the actuator portion due to contraction of one of the second portion and the third portion Becomes large, and a decrease in the deformation amount of one actuator portion as a whole can be suppressed. In a configuration that satisfies the requirements of the second aspect described above, when the positional deviation in the first direction occurs between the flow path unit and the piezoelectric actuator, and the separation distance in the first direction from the pressure chamber of the second part becomes short. Alternatively, when the second portion overlaps the pressure chamber in the third direction, the deformation amount of the actuator portion due to the contraction of the second portion is increased, and a decrease in the deformation amount as a whole of one actuator portion is suppressed. That is, by satisfying any of the above requirements, it is possible to suppress a decrease in the deformation amount of the actuator portion due to the positional deviation.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the deformation amount of an actuator part by the position shift between a flow path unit and a piezoelectric actuator can be suppressed.

1 is an overall configuration diagram of a printer including a head according to a first embodiment of the present invention. It is a top view of the head of FIG. FIG. 3 is a plan view showing the upper surfaces of three piezoelectric layers in the piezoelectric actuator of FIG. 2, wherein (a) is the upper surface of the uppermost piezoelectric layer, (b) is the upper surface of the intermediate piezoelectric layer, and (c) is the lowermost layer. The upper surface of a piezoelectric layer is shown. FIG. 4 is a cross-sectional view taken along line IV-IV in FIGS. 2 and 3. FIG. 5 is a cross-sectional view taken along line VV in FIGS. 2 and 3. FIG. 6 is an enlarged view of a region VI in FIG. 5 illustrating an operation of the actuator unit. FIG. 7 is a diagram corresponding to FIG. 6 and illustrating the operation of the actuator unit when a positional shift in the X direction occurs. It is a top view equivalent to Drawing 3 (c) in a head concerning a 2nd embodiment of the present invention. FIGS. 9A and 9B are enlarged views of one actuator unit corresponding to a region IX in FIG. 8, where FIG. 9A shows a state where there is no positional deviation, and FIG. It is a graph which shows an analysis result. (A)-(c) is a figure corresponding to field VI of Drawing 5 of a head concerning the 1st, 2nd, and 3rd modification of the present invention, respectively. (A)-(c) is a figure corresponding to field VI of Drawing 5 of a head concerning the 4th, 5th, and 6th modification of the present invention, respectively.

<First Embodiment>
First, the overall configuration of the printer 1 including the head 3 according to the first embodiment of the present invention will be described with reference to FIG.

  In the following description, the Z direction is a vertical direction, and the X direction and the Y direction are 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 X direction corresponds to the first direction, the Y direction corresponds to the second direction, and the Z direction corresponds to the third direction.

  The printer 1 includes a head 3, a carriage 2, and two transport roller pairs 4.

  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.

  The head 3 is a serial type, is mounted on the carriage 2, and can move in the Y direction together with the carriage 2. On the lower surface of the head 3 (surface facing downward in the Z direction), 32 discharge ports 15x are opened. The lower surface of the head 3 is a discharge surface 34x that defines 32 discharge ports 15x (see FIG. 4). The discharge surface 34x is parallel to the X direction and the Y direction, and is orthogonal to the Z direction.

  The two conveying roller pairs 4 are arranged with the carriage 2 sandwiched in the X direction. By rotating the conveyance roller pair 4 with the sheet P being sandwiched, the sheet P is conveyed in the conveyance direction along the X direction.

  A control unit (not shown) of the printer 1 transports the paper P by a predetermined amount in the transport direction by the discharge operation of discharging the ink from the discharge port 15x while moving the head 3 in the Y direction together with the carriage 2, and the transport roller pair 4. The transfer operation is alternately performed. As a result, an image is recorded on the paper P.

  Next, the configuration of the head 3 will be described with reference to FIGS.

  As shown in FIG. 2, the head 3 includes a flow path unit 21, a piezoelectric actuator 22, and a COF (Chip On Film) 23.

  In the flow path unit 21, one end 21a in the X direction and the other end 21b in the X direction are both parallel to the Y direction, and one end 21c in the Y direction and the other end 21d in the Y direction are both parallel to the X direction. In the piezoelectric actuator 22, one end 22a in the X direction and the other end 22b in the X direction are both parallel to the Y direction, and one end 22c in the Y direction and the other end 22d in the Y direction are both parallel to the X direction. That is, the flow path unit 21 and the piezoelectric actuator 22 are both substantially rectangular when viewed from the Z direction. The flow path unit 21 has a size that is slightly larger than the piezoelectric actuator 22 when viewed from the Z direction.

  As shown in FIG. 4, the flow path unit 21 includes four plates 31 to 34 stacked in the Z direction.

  Thirty-two pressure chambers 10 are formed in the plate 31. As shown in FIG. 2, each of the 32 pressure chambers 10 is substantially rectangular when viewed from the Z direction, and the length in the Y direction is longer than the length in the X direction. The 32 pressure chambers 10 form four pressure chamber rows 9. Each of the four pressure chamber rows 9 extends in the X direction and includes eight pressure chambers 10. In each of the four pressure chamber rows 9, eight pressure chambers 10 are arranged at equal intervals in the X direction. The four pressure chamber rows 9 are arranged in the Y direction.

  As shown in FIG. 4, through holes 12 and 13 are formed in the plate 32 for each pressure chamber 10. The through holes 12 and 13 respectively overlap the corresponding one of the pressure chamber 10 in the Y direction with one end 10c in the Y direction and the other end 10d in the Y direction. Here, the ink flows through the through hole 12 in the Z direction and flows through the pressure chamber 10 in the Y direction. The cross-sectional area perpendicular to the Z direction in the through hole 12 is smaller than the cross-sectional area perpendicular to the Y direction in the pressure chamber 10. Therefore, the through hole 12 functions as a throttle channel.

  A through hole 14 is formed in the plate 33 for each through hole 13. The through holes 14 overlap the corresponding through holes 13 in the Z direction.

  Four manifold channels 11 are further formed in the plate 33. The four manifold channels 11 correspond to each of the four pressure chamber rows 9 as shown in FIG. Each manifold channel 11 has a portion that extends in the X direction and overlaps the eight pressure chambers 10 of the corresponding pressure chamber row 9 in the Z direction.

  On the upper surface of the plate 31, four ink supply ports 8 are formed in a region where the piezoelectric actuator 22 is not disposed. Each of the four ink supply ports 8 is in a position overlapping with one end in the X direction (the lower end in FIG. 2) of the four manifold channels 11 in the Z direction. Ink is supplied from the four ink supply ports 8 to each of the four manifold channels 11.

  On the plate 34, 32 nozzles 15 are formed. Each of the 32 nozzles 15 overlaps with the through hole 14 in the Z direction. The opening of the nozzle 15 opened on the lower surface (discharge surface 34x) of the plate 34 corresponds to the discharge port 15x.

  Each of the four manifold channels 11 communicates with the eight pressure chambers 10 of the corresponding pressure chamber row 9 via the through holes 12. The pressure chamber 10 communicates with the discharge port 15x of the nozzle 15 through the through holes 13 and 14, respectively.

  As shown in FIG. 4, the piezoelectric actuator 22 is stacked on the flow path unit 21 in the Z direction, and is disposed on the upper surface of the plate 31.

  The piezoelectric actuator 22 includes a piezoelectric body 40, an ink separation layer 44, 32 drive electrodes 51, a high potential electrode 52, and a low potential electrode 53.

  The piezoelectric body 40 has three piezoelectric layers 41 to 43 stacked in the Z direction. The piezoelectric layers 41 to 43 and the ink separation layer 44 have the same shape and size in a plane along the X direction and the Y direction, and the outer shape of the substantially rectangular piezoelectric actuator 22 as viewed from the Z direction as shown in FIG. Is defined.

  As shown in FIG. 4, the ink separation layer 44 is disposed on the upper surface of the plate 31 and covers all the pressure chambers 10 formed in the plate 31. The ink separation layer 44 is made of, for example, a metal material such as stainless steel, a piezoelectric material mainly composed of lead zirconate titanate, a synthetic resin material, or the like.

  The piezoelectric layer 43 is disposed on the upper surface of the ink separation layer 44. The piezoelectric layer 42 is disposed on the upper surface of the piezoelectric layer 43. The piezoelectric layer 41 is disposed on the upper surface of the piezoelectric layer 42. Each of the piezoelectric layers 41 to 43 overlaps the ink separation layer 44 in the Z direction. The piezoelectric layers 41 to 43 are made of a piezoelectric material mainly composed of lead zirconate titanate.

  The 32 drive electrodes 51, the high potential electrode 52, and the low potential electrode 53 are different from each other in the Z direction. Specifically, 32 drive electrodes 51, a high potential electrode 52, and a low potential electrode 53 are arranged in order from the top in the Z direction. The 32 drive electrodes 51 are farther from the pressure chamber 10 in the Z direction than the high potential electrode 52 and the low potential electrode 53. The high potential electrode 52 is farther from the pressure chamber 10 in the Z direction than the low potential electrode 53. The high potential electrode 52 and the low potential electrode 53 are spaced apart from the 32 drive electrodes 51 in the Z direction.

  In the present embodiment, there is no positional deviation between the flow path unit 21 and the piezoelectric actuator 22, and the electrodes and active portions of the piezoelectric actuator 22 described below and the pressure chamber 10 of the flow path unit 21 This positional relationship is for the case where there is no positional deviation.

  As shown in FIG. 2, the 32 drive electrodes 51 are provided on the upper surface of the piezoelectric layer 41 so as to correspond to the pressure chambers 10 formed in the plate 31. The 32 drive electrodes 51 each have a main part 51a and a protruding part 51b. The main part 51a is a substantially rectangular part when viewed from the Z direction, a part that overlaps the substantially entire region of the corresponding pressure chamber 10 in the Z direction, and a corresponding pressure chamber 10 on both sides of the X direction in the Z direction. And non-overlapping parts. The length of the main portion 51a in the X direction is longer than the length of the corresponding pressure chamber 10 in the X direction. The protruding portion 51b is a portion protruding in the Y direction from the main portion 51a, and does not overlap with the corresponding pressure chamber 10 in the Z direction. In the 32 drive electrodes 51, the protruding directions of the protruding portions 51b are the same. The protrusion 51 b is provided with a contact point that is electrically connected to the wiring of the COF 23.

  The driver IC 24 mounted on the COF 23 individually applies either a high potential (VDD potential) or a low potential (GND potential) to the 32 drive electrodes 51 via the wiring of the COF 23.

  As shown in FIG. 4, the high potential electrode 52 is formed on the upper surface of the piezoelectric layer 42, and is disposed between the piezoelectric layer 41 and the piezoelectric layer 42 in the Z direction.

  As shown in FIG. 3B, the high potential electrode 52 includes 32 individual parts 52a, four connection parts 52b, a connection part 52c, and a lead part 52d. The 32 individual parts 52a overlap with the center part in the X direction of each pressure chamber 10 formed in the plate 31 in the Z direction. The four connection portions 52b correspond to the four pressure chamber rows 9 respectively. Each connecting portion 52b extends in the X direction, and connects one end (the right end in FIG. 3B) of the individual portion 52a corresponding to each of the eight pressure chambers 10 of the pressure chamber row 9 to each other. Yes. The connection part 52c extends in the Y direction, and connects one end (the lower end of FIG. 3B) of the four connection parts 52b in the X direction. The lead-out portion 52d is drawn from the other end in the Y direction of the connecting portion 52c (the left end in FIG. 3B) from the one end 22a in the X direction of the piezoelectric actuator 22 toward the other end 22b in the X direction. The direction in which the lead-out portion 52d extends from the connection portion 52c is the same as the direction in which the four connection portions 52b extend from the connection portion 52c. The lead portion 52d is connected to the surface electrode 72 through a through hole 41x (see FIG. 3A) formed in the piezoelectric layer 41. The surface electrode 72 is disposed on the upper surface of the piezoelectric layer 41 so as to overlap the lead portion 52d in the Z direction. The surface electrode 72 is electrically connected to the wiring of the COF 23.

  The driver IC 24 applies a high potential (VDD potential) to the high potential electrode 52 via the wiring of the COF 23.

  As shown in FIG. 4, the low potential electrode 53 is formed on the upper surface of the piezoelectric layer 43, and is disposed between the piezoelectric layer 42 and the piezoelectric layer 43 in the Z direction.

  As shown in FIG. 3C, the low-potential electrode 53 includes 32 individual parts 53a, four connection parts 53b, a connection part 53c, and a lead-out part 53d. The 32 individual portions 53a are arranged at positions adjacent to each of the pressure chambers 10 formed in the plate 31 in the X direction and not overlapping in the Z direction. An individual portion 53a is disposed between two pressure chambers 10 adjacent to each other in the X direction. Furthermore, the individual portion 53a is disposed between the one end 22a in the X direction of the piezoelectric actuator 22 and the pressure chamber 10 adjacent to the one end 22a in the X direction. The four connection portions 53b correspond to the four pressure chamber rows 9 respectively. Each connecting portion 53b extends in the X direction, and connects the other ends in the Y direction (left end in FIG. 3C) of the individual portions 53a corresponding to the eight pressure chambers 10 in the pressure chamber row 9 respectively. ing. The connection portion 53c extends in the Y direction and connects the other ends in the X direction of the four connection portions 53b (upper ends in FIG. 3C). The lead portion 53d is drawn from the other end in the Y direction of the connecting portion 53c (the left end in FIG. 3C) from the other end 22b in the X direction of the piezoelectric actuator 22 toward one end 22a in the X direction. The direction in which the lead-out portion 53d extends from the connection portion 53c is the same as the direction in which the four connection portions 53b extend from the connection portion 53c. The lead-out portion 53d is connected to the surface electrode 73 via a through hole 41y (see FIG. 3A) formed in the piezoelectric layer 41 and a through hole 42y (see FIG. 3B) formed in the piezoelectric layer 42. It is connected. The surface electrode 73 is disposed on the upper surface of the piezoelectric layer 41 so as to overlap the lead portion 53d in the Z direction. The surface electrode 73 is electrically connected to the wiring of the COF 23.

  The driver IC 24 applies a low potential (GND potential) to the low potential electrode 53 via the wiring of the COF 23.

  With the arrangement of the electrodes 51 to 53 as described above, among the 32 drive electrodes 51, the drive electrodes 51 excluding the four drive electrodes 51 located at the other end in the X direction (the upper end in FIG. 3A) As shown in FIG. 5, in the central portion in the X direction of the main portion 51 a, it overlaps with the individual portion 52 a of the high potential electrode 52 in the Z direction, and the low potential electrode 53 of both ends of the main portion 51 a in the X direction. It overlaps with the individual part 53a in the Z direction. Each of the four drive electrodes 51 overlaps with the individual portion 52a of the high potential electrode 52 in the Z direction at the center portion in the X direction of the main portion 51a, and the low potential electrode 53 of one end in the X direction of the main portion 51a. It overlaps with the individual portion 53a in the Z direction, and overlaps with the connection portion 53c of the low potential electrode 53 in the Z direction at the other end in the X direction of the main portion 51a.

  A portion of the piezoelectric layer 41 sandwiched between the drive electrode 51 and the high potential electrode 52 in the Z direction is referred to as a “first active portion 61”. The portions of the piezoelectric layers 42 and 43 sandwiched between the drive electrode 51 and the low potential electrode 53 in the Z direction are referred to as “second active portions 62 and 63”. The first active portion 61 is mainly polarized upward, and the second active portions 62 and 63 are mainly polarized downward.

  In the present embodiment, the drive electrode 51 corresponds to a “first electrode”, the high potential electrode 52 corresponds to a “second electrode”, and the low potential electrode 53 corresponds to a “third electrode”. The first active part 61 corresponds to the “first part”, the second active part 62 corresponds to the “second part”, and the second active part 63 corresponds to the “third part”.

  The piezoelectric actuator 22 includes an actuator unit 60 that includes one first active unit 61 and two second active units 62 and 63 for each pressure chamber 10. Here, the second active portions 62 and 63 have a function of suppressing crosstalk. Crosstalk refers to a phenomenon in which pressure fluctuation accompanying deformation of the actuator unit 60 in a certain pressure chamber 10 is transmitted to another pressure chamber 10 adjacent to the pressure chamber 10 in the X direction.

  In the present embodiment, as described above, there is no positional deviation between the flow path unit 21 and the piezoelectric actuator 22, and the first active portion in the X direction with respect to each of the 32 pressure chambers 10. The center 61 c of 61 is at the same position as the center of the pressure chamber 10.

  FIG. 5 shows the X direction and the Z direction passing through the two pressure chambers 10 adjacent to each other in the X direction and the active portions 61 to 63 of the two actuator units 60 corresponding to the two pressure chambers 10, respectively. It is a cross section.

  Hereinafter, referring to the left actuator unit 60 and the pressure chamber 10 in FIG. 5, the positional relationship between the active units 61 to 63 in one actuator unit 60, and the active units 61 to 63 of one actuator unit 60 and corresponding to this A positional relationship with the one pressure chamber 10 will be described.

  The second active portions 62 and 63 are spaced apart from each other in the X direction, and are disposed symmetrically with respect to an axis along the Z direction passing through the center 61 c of the first active portion 61 in the X direction. The first active portion 61 is disposed between the second active portions 62 and 63 in the X direction, and is separated from each of the second active portions 62 and 63 in the X direction.

  The first active portion 61 has a portion that overlaps the pressure chamber 10 in the Z direction. Specifically, the first active portion 61 overlaps the central portion in the X direction of the pressure chamber 10 in the Z direction.

  The second active parts 62 and 63 do not overlap the pressure chamber 10 in the Z direction. In the X direction, the second active portion 62 is located between one end 10a in the X direction of the pressure chamber 10 (left end in FIG. 5) and one end 22a in the X direction of the piezoelectric actuator 22 (see FIG. 3). The second active portion 63 is located between the other end 10b in the X direction of the pressure chamber 10 (the right end in FIG. 5) and the other end 22b in the X direction of the piezoelectric actuator 22 (see FIG. 3) in the X direction. . The other end 10b is located between the one end 10a and the other end 22b of the piezoelectric actuator 22 in the X direction in the X direction.

  The positional relationship between the end portions in the X direction of the pressure chamber 10 and the active portions 61 to 63 is as follows.

  One end 61a and the other end 61b in the X direction of the first active portion 61 are located between one end 10a and the other end 10b in the X direction of the pressure chamber 10 in the X direction. The other end 61b is located between the one end 61a and the other end 22b of the piezoelectric actuator 22 in the X direction in the X direction.

  One end 62 a and the other end 62 b in the X direction of the second active portion 62 are positioned between one end 10 a in the X direction of the pressure chamber 10 and one end 22 a in the X direction of the piezoelectric actuator 22 in the X direction. The other end 62b is located between the one end 62a and the other end 22b of the piezoelectric actuator 22 in the X direction in the X direction.

  One end 63 a and the other end 63 b in the X direction of the second active portion 63 are located between the other end 10 b in the X direction of the pressure chamber 10 and the other end 22 b in the X direction of the piezoelectric actuator 22 in the X direction. The other end 63b is located between the one end 63a and the other end 22b of the piezoelectric actuator 22 in the X direction in the X direction.

  In the present embodiment, as described above, the second active portions 62 and 63 are arranged symmetrically with respect to the axis along the Z direction passing through the center 61c, and the position between the flow path unit 21 and the piezoelectric actuator 22 is set. There is no deviation. Therefore, the distance d2 in the X direction from the other end 62b in the X direction of the second active portion 62 to the one end 10a in the X direction of the pressure chamber 10, and the second active portion 63 from the other end 10b in the X direction of the pressure chamber 10 The distance d3 in the X direction to the one end 63a in the X direction is the same.

  The other end 62b in the X direction of the second active portion 62 and the one end 10a in the X direction of the pressure chamber 10 are the one end 22a in the X direction of the piezoelectric actuator 22 and the center 61c in the X direction in the first active portion 61 in the X direction. Located between and. The distance d4 in the X direction from the other end 62b to the center 61c is longer than half the length D of the pressure chamber 10 in the X direction (that is, the distance in the X direction from the one end 10a to the other end 10b) D.

  One end 63a in the X direction of the second active part 63 and the other end 10b in the X direction of the pressure chamber 10 are the center 61c in the X direction in the first active part 61 and the other end in the X direction of the piezoelectric actuator 22 in the X direction. 22b. The distance d5 in the X direction from the center 61c to the one end 63a is longer than half of the length D of the pressure chamber 10 in the X direction.

  Since the second active portions 62 and 63 are disposed symmetrically with respect to the axis along the Z direction passing through the center 61c, the distances d4 and d5 are the same.

  In a cross section along the X direction and the Z direction passing through the pressure chamber 10, the first active portion 61, and the second active portions 62 and 63 (that is, a cross section orthogonal to the Y direction: see FIG. 5), the second in the X direction. The separation distance (d4 + d5) between the active part 62 and the second active part 63 is longer than the length D of the pressure chamber 10 in the X direction. In other words, the separation distance (d4 + d5) is a distance in the X direction from the other end 62b in the X direction of the second active portion 62 to one end 63a in the X direction of the second active portion 63.

  The separation distance (d4 + d5) is, for example, when the length D of the pressure chamber 10 in the X direction is 340 μm, the length of the drive electrode 51 in the X direction is 438 μm, and the length of the first active portion 61 in the X direction is 220 μm. Based on the analysis result described later, it is preferable that the length is not less than the length obtained by adding 30 μm to the length D and not more than the length obtained by adding 140 μm to the length D. That is, the distances d2 and d3 are preferably 15 μm or more and 70 μm or less.

  Furthermore, with reference to FIG. 5, the positional relationship between the active parts 61-63 of the actuator part 60 provided with respect to the two pressure chambers 10 adjacent to each other in the X direction will be described.

  In the X direction, the first active part 61 provided for one of the two pressure chambers 10 (the left pressure chamber 10 in FIG. 5) and the other (the right pressure chamber 10 in FIG. 5) Between the first active part 61 provided for the second active part 61, a second active part 63 provided for one side and a second active part 62 provided for the other side are arranged.

  The distance d1 between the active parts 63 and 62 is, for example, that the length D of the pressure chamber 10 in the X direction is 340 μm, the length of the drive electrode 51 in the X direction is 438 μm, and the length of the first active part 61 in the X direction is 220 μm, one of the two pressure chambers 10 (left pressure chamber 10 in FIG. 5) from the other end 10b in the X direction to the other end 10a in the X direction (right pressure chamber 10 in FIG. 5). When the distance W in the X direction is 84 μm, it is preferably 60 μm or more from the viewpoint of preventing a short circuit between the drive electrodes 51 constituting the active portions 63 and 62. The separation distance d1 is along the X direction and the Z direction passing through the second active portion 63 provided for one of the two pressure chambers 10 and the second active portion 62 provided for the other. In the cross section (ie, the cross section orthogonal to the Y direction: see FIG. 5), the second active portion 63 provided for one side and the second active portion 62 provided for the other side are separated in the X direction. Distance. In other words, the separation distance d1 is from the other end 63b in the X direction of the second active part 63 provided for one of the two pressure chambers 10 to the other of the second active part 62 provided for the other. This is the distance in the X direction to the one end 62a in the X direction.

  Next, with reference to FIG. 6, the operation of the actuator unit 60 corresponding to the ejection port 15x when ejecting ink from a certain ejection port 15x will be described.

  Before the printer 1 starts the recording operation, a low potential (GND potential) is applied to the 32 drive electrodes 51 as shown in FIG. At this time, in each of the 32 actuator parts 60, due to the potential difference between the drive electrode 51 and the high potential electrode 52, an upward electric field equal to the polarization direction is generated in the first active part 61, so that the first active part 61 It contracts in the direction (direction along the X direction and the Y direction). As a result, the portion of the laminate composed of the piezoelectric body 40 and the ink separation layer 44 that overlaps the pressure chamber 10 in the Z direction is bent toward the pressure chamber 10 (downward). At this time, the pressure chamber 10 has a smaller volume than the case where the laminate is flat.

  When the printer 1 starts a recording operation and ink is ejected from a certain ejection port 15x, first, as shown in FIG. 6B, the potential of the drive electrode 51 corresponding to the ejection port 15x is low ( The potential is switched from (GND potential) to high potential (VDD potential). At this time, the contraction of the first active part 61 is eliminated by eliminating the potential difference between the drive electrode 51 and the high potential electrode 52 in the actuator part 60. On the other hand, when a potential difference between the drive electrode 51 and the low potential electrode 53 is generated, a downward electric field equal to the polarization direction is generated in the second active portions 62 and 63, and the second active portions 62 and 63 contract in the surface direction. . However, the second active parts 62 and 63 have a crosstalk suppressing function as described above, and contribute almost to the deformation of the actuator part 60 when there is no positional deviation between the flow path unit 21 and the piezoelectric actuator 22. do not do. That is, at this time, the laminate does not bend so that the portion overlapping the pressure chamber 10 in the Z direction is convex in the direction away from the pressure chamber 10 (upward), and is in a flat state. Thereby, the volume of the pressure chamber 10 becomes larger than that in FIG.

  Thereafter, as shown in FIG. 6A, the potential of the drive electrode 51 corresponding to the ejection port 15x is switched from a high potential (VDD potential) to a low potential (GND potential). At this time, in the actuator unit 60, the potential difference between the drive electrode 51 and the low potential electrode 53 is eliminated, and thus the contraction of the second active units 62 and 63 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the high potential electrode 52, an upward electric field equal to the polarization direction is generated in the first active portion 61, and the first active portion 61 contracts in the surface direction. Thereby, the part which overlaps with the pressure chamber 10 in the said laminated body in a Z direction bends so that it may become convex toward the pressure chamber 10 (downward). At this time, since the volume of the pressure chamber 10 is greatly reduced, a large pressure is applied to the ink in the pressure chamber 10, and the ink is ejected from the ejection port 15x.

  In the present embodiment, AL (Acoustic Length: 1/2 of the acoustic resonance period in the pressure chamber 10 of the pressure wave generated in the pressure chamber 10 due to the deformation of the actuator unit 60) is 4.5 μs or less. For example, AL is 4.3 μs, and the driving frequency of the piezoelectric actuator 22 is 18 kHz.

  FIG. 6 is a diagram for explaining the operation of one actuator unit 60 when there is no positional deviation between the flow path unit 21 and the piezoelectric actuator 22. On the other hand, for example, when a displacement in the X direction occurs as shown in FIG. 7, the deformation amount of one actuator unit 60 decreases to some extent.

  In FIG. 7, a part of the second active part 62 overlaps the pressure chamber 10 in the Z direction. That is, the second active portion 62 includes a portion that overlaps the pressure chamber 10 in the Z direction and a portion that does not overlap the pressure chamber 10 in the Z direction. The second active portion 63 has a longer distance in the X direction from the pressure chamber 10 than that in FIG. That is, the distance d3 in the X direction from the other end 10b in the X direction of the pressure chamber 10 (the right end in FIG. 7) to the one end 63a in the X direction of the second active portion 63 is longer than that in FIG. However, even when the positional deviation in the X direction occurs in this way, the requirement that the separation distance (d4 + d5) is longer than the length D of the pressure chamber 10 in the X direction, and the distances d4 and d5 are in the X direction of the pressure chamber 10. The requirement that it is longer than half of the length D is satisfied.

  Also in the example of FIG. 7, as in FIG. 6, the contraction of the first active part 61 (FIG. 7A) and the contraction of the second active parts 62 and 63 (FIG. 7) according to the change in the potential of the drive electrode 51. (B)) occurs sequentially. However, compared with the case where there is no position shift (FIG. 6), the deformation amount of the deformation that bends downward so that the actuator portion 60 protrudes downward due to the contraction of the first active portion 61 is reduced, and the contraction of the second active portion 62 The deformation amount of the deformation that bends so as to be convex upward is increased. That is, the amount of deformation of one actuator unit 60 when there is a positional deviation in the X direction is one actuator when there is no positional deviation because the amount of deformation of the actuator unit 60 due to the contraction of the first active unit 61 is reduced. Although the amount of deformation is lower than the deformation amount of the portion 60, the deformation amount of the actuator portion 60 due to the contraction of the second active portion 62 is increased (see FIG. 7B). Reduction is suppressed.

  That is, according to the present embodiment, the distance (d4 + d5) is longer than the length D of the pressure chamber 10 in the X direction, and the distances d4 and d5 are half of the length D of the pressure chamber 10 in the X direction. By satisfying the requirement of “long”, the amount of deformation of the actuator unit 60 when there is no positional deviation is deliberately reduced as compared with the case where the above requirement is not satisfied. And when the position shift of a X direction arises, the deformation amount of the actuator part 60 by one contraction of the 2nd active parts 62 and 63 becomes large, and the fall of the deformation amount as one actuator part 60 whole is suppressed. It is done. That is, by satisfying the above requirements, it is possible to suppress a decrease in the deformation amount of the actuator unit 60 due to the positional deviation in the X direction.

  The separation distance (d4 + d5) is preferably 30 μm or more longer than the length D of the pressure chamber 10 in the X direction. This is because, as will be understood from the analysis result described later, it is possible to more reliably suppress a decrease in the deformation amount of the actuator unit 60 due to the displacement in the X direction.

  The 32 drive electrodes 51 are farther from the pressure chamber 10 in the Z direction than the high potential electrode 52 and the low potential electrode 53. The high potential electrode 52 is farther from the pressure chamber 10 in the Z direction than the low potential electrode 53. Such electrode arrangement facilitates the formation of the active portions 61 to 63.

  In the present embodiment, the drive electrode 51, the high potential electrode 52, the low potential electrode 53, the first active portion 61, the second active portion 62, and the second active portion provided for the left pressure chamber 10 in FIG. 63 corresponds to “first electrode”, “second electrode”, “third electrode”, “first part”, “second part”, and “third part”. The drive electrode 51, the high potential electrode 52, the low potential electrode 53, the first active portion 61, the second active portion 62, and the second active portion 63 provided for the right pressure chamber 10 in FIG. This corresponds to “four electrodes”, “fifth electrode”, “sixth electrode”, “fourth part”, “fifth part”, and “sixth part”. Here, the X direction passing through the second active portion 63 provided for the left pressure chamber 10 in FIG. 5 and the second active portion 62 provided for the right pressure chamber 10 in FIG. 5. In the cross section along the Z direction, the separation distance d1 between the second active portion 63 and the second active portion 62 in the X direction is preferably 60 μm or more. In this case, a short circuit between the drive electrodes 51 can be reliably prevented.

  The length D in the X direction of the pressure chamber 10 is preferably 340 μm or less. As the length D is shorter, the pressure chambers 10 can be arranged at a higher density. However, the deformation amount of the actuator unit 60 is significantly reduced due to the displacement in the X direction between the flow path unit 21 and the piezoelectric actuator 22. obtain. In this respect, according to the present embodiment, a decrease in the deformation amount of the actuator unit 60 due to a positional shift in the X direction between the flow path unit 21 and the piezoelectric actuator 22 can be suppressed. Ten high density arrangements are possible.

  AL (Acoustic Length: 1/2 of the acoustic resonance period in the pressure chamber 10 of the pressure wave generated in the pressure chamber 10 due to the deformation of the actuator unit 60) is 4.5 μs or less. The shorter the AL is, the higher the drive frequency of the piezoelectric actuator 22 can be. On the other hand, as the length D of the pressure chamber 10 is shorter, the AL is shorter, so that the pressure chambers 10 can be arranged at a high density. However, due to the displacement in the X direction between the flow path unit 21 and the piezoelectric actuator 22. A decrease in the deformation amount of the actuator unit 60 can be significant. In this respect, according to the present embodiment, since it is possible to suppress a decrease in the deformation amount of the actuator unit 60 due to the positional deviation in the X direction between the flow path unit 21 and the piezoelectric actuator 22, the AL is shortened, The driving frequency can be increased.

Second Embodiment
Subsequently, a head according to a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in the configuration of 32 individual portions 253a and connection portions 253c in the low potential electrode 253.

  In the present embodiment, the 32 individual parts 253a each have a wide part 254 and a narrow part 255 arranged in the Y direction, as shown in FIG. The wide portion 254 is disposed between the connection portion 53b and the narrow portion 255 in the Y direction. The width of the wide portion 254 (the length in the X direction) is larger than the width of the narrow portion 255. The center of the wide portion 254 in the X direction and the center of the narrow portion 255 in the X direction coincide with each other in the X direction. Accordingly, each individual portion 253a has a convex shape when viewed from the Z direction.

  The connecting portion 253c has four concave portions 257 on one side in the X direction (the lower end in FIG. 8). The four concave portions 257 correspond to the four pressure chamber rows 9 respectively. Each recess 257 is located at a position overlapping the narrow portion 255 corresponding to the pressure chamber row 9 in the X direction. The connecting portion 253c has a wide portion 258 and a narrow portion 259 corresponding to each concave portion 257. The width of the wide portion 258 (the length in the X direction) is larger than the width of the narrow portion 259.

  With this configuration of the low-potential electrode 253, in the present embodiment, as shown in FIG. 9A, in the single actuator unit 60, the second active units 62 and 63 are respectively connected to the drive electrode 51 in the Z direction. And portions 62x and 63x sandwiched between the wide portion 254 or the wide portion 258 and portions 62y and 63y sandwiched between the drive electrode 51 and the narrow portion 255 or the narrow portion 259 in the Z direction. The width of the portion 62x is larger than the width of the portion 62y. The width of the portion 63x is larger than the width of the portion 63y. The width of the portion 62x is the same as the width of the portion 63x. The width of the portion 62y is the same as the width of the portion 63y.

  The distance (d4 + d5) between the second active part 62 and the second active part 63 in the X direction in the cross section along the X direction and the Z direction passing through the parts 62x and 63x is the X direction and Z passing through the parts 62y and 63y. It is shorter than the separation distance (d4 ′ + d5 ′) between the second active part 62 and the second active part 63 in the X direction in the cross section along the direction. The separation distance (d4 + d5) and the separation distance (d4 ′ + d5 ′) are based on the length in the X direction of the pressure chamber 10 corresponding to the actuator unit 60 (that is, the distance in the X direction from the one end 10a to the other end 10b) D. Also long.

  As shown in FIG. 9A, when there is no positional deviation between the flow path unit 21 and the piezoelectric actuator 22, the second cross section along the X direction and the Z direction passing through the portions 62x and 63x. The distance d2 in the X direction from the other end 62b in the X direction of the active part 62 to the one end 10a in the X direction of the pressure chamber 10 and the X direction of the second active part 63 from the other end 10b in the X direction of the pressure chamber 10 The distance d3 in the X direction to the one end 63a is the same. Further, in a cross section along the X direction and the Z direction passing through the portions 62y, 63y, a distance d2 ′ in the X direction from the other end 62b in the X direction of the second active portion 62 to one end 10a in the X direction of the pressure chamber 10; The distance d3 ′ in the X direction from the other end 10b in the X direction of the pressure chamber 10 to the one end 63a in the X direction of the second active portion 63 is the same. The distances d2 and d3 are shorter than the distances d2 'and d3'.

  In a cross section along the X direction and the Z direction passing through the portions 62x and 63x, the distance d4 in the X direction from the other end 62b to the center 61c in the X direction in the first active portion 61, and the X from the center 61c to the one end 63a The distance d5 in the direction is the same length as each other, and is longer than half of the length D of the pressure chamber 10 in the X direction. In a cross section along the X direction and the Z direction passing through the portions 62y and 63y, a distance d4 ′ in the X direction from the other end 62b to the center 61c and a distance d5 ′ in the X direction from the center 61c to the one end 63a are The length is the same, and is longer than half the length D of the pressure chamber 10 in the X direction. The distances d4 and d5 are shorter than the distances d4 'and d4'.

  On the other hand, for example, as shown in FIG. 9B, when a displacement in the rotational direction about the axis O along the Z direction occurs between the flow path unit 21 and the piezoelectric actuator 22, one actuator The separation distance (d4 + d5) and the separation distance (d4 ′ + d5 ′) are longer than the length D in the X direction of the pressure chamber 10 between the active portions 61 to 63 of the portion 60 and the corresponding one pressure chamber 10. Although the requirement that it is long and the requirements that the distances d4, d5, d4 ′, d5 ′ are longer than half of the length D in the X direction of the pressure chamber 10 are maintained, the positional relationship between them is misaligned in the rotational direction. It is different from the case without it.

  In FIG. 9B, the first active part 61 is closer to the X direction between the center 61 c in the X direction in the first active part 61 and the center in the X direction in the pressure chamber 10 as the part is separated from the axis O in the Y direction. The distance is getting bigger. In the portion 62x of the second active portion 62, the distance d2 is shorter than that in the portion away from the axis O in the Y direction compared to FIG. The other end in the Y direction of the portion 62x (the left end in FIG. 9B) overlaps the pressure chamber 10 in the Z direction. In the portion 62y, the distance d2 'is longer than that in FIG. 9A as the portion is separated from the axis O in the Y direction. In the portion 63x of the second active portion 63, the distance d3 is longer as compared to FIG. 9A as the portion is separated from the axis O in the Y direction. In the portion 63y, the distance d3 'is shorter than that in FIG. 9A as the portion is separated from the axis O in the Y direction.

  In this case, the amount of contraction of the first active part 61 decreases as the part is separated from the axis O in the Y direction, and the amount of deformation of the actuator unit 60 due to the contraction decreases. In the second active parts 62 and 63, there are parts where the separation distance from the pressure chamber 10 in the X direction becomes longer in the parts 62y and 63x. The deformation amount of the actuator unit 60 due to the contraction of the portion is smaller than that in the case where there is no positional deviation in the rotation direction, as will be understood from the analysis result described later. On the other hand, in the portions 62x and 63y, there are portions where the separation distance from the pressure chamber 10 in the X direction is shortened and portions where the pressure chamber 10 overlaps in the Z direction. The amount of deformation of the actuator unit 60 due to the contraction of the portion is larger than that in the case where there is no positional deviation in the rotational direction, as will be understood from the analysis result described later. That is, the amount of deformation of one actuator unit 60 when there is a positional deviation in the rotational direction is the amount of deformation of the actuator unit 60 due to the contraction of the first active unit 61 and the contraction of the portions 62y and 63x of the second active units 62 and 63. The amount of deformation of the actuator unit 60 due to the reduction is smaller than the amount of deformation of one actuator unit 60 when there is no positional deviation in the rotational direction, but the contraction of the portions 62x and 63y of the second active portions 62 and 63 By increasing the deformation amount of the actuator unit 60 due to the above, a decrease in the deformation amount of one actuator unit 60 as a whole is suppressed.

  In the present embodiment, as shown in FIG. 9A, the separation distance (d4 + d5) and the separation distance (d4 ′ + d5 ′) are different from each other (that is, the second active portion 62 and the second active portion 62 in the X direction). 2 The separation distance from the active part 63 is not constant in the Y direction). On the other hand, when the separation distance (d4 + d5) is constant in the Y direction as in the first embodiment (for example, when the width of the narrow portion 255 is the same as the width of the wide portion 254), FIG. When such a positional deviation in the rotational direction occurs, not only the portion 62x but also the portion 63y has a position where the separation distance from the pressure chamber 10 in the X direction is a predetermined distance or less (for example, a position overlapping the pressure chamber 10 in the Z direction). ). That is, when the separation distance is constant in the Y direction, if the positional deviation in the rotational direction occurs, the separation distance from the pressure chamber 10 is greater in the second active portions 62 and 63 than in the case where the separation distance is not constant in the Y direction. The region arranged at a position that is equal to or less than the predetermined distance becomes large, and the deformation amount of the actuator unit 60 can be excessively increased. On the other hand, in the present embodiment, since the separation distance is not constant in the Y direction, the separation distance from the pressure chamber 10 is equal to or less than the predetermined distance in the second active portions 62 and 63 even if a positional deviation in the rotation direction occurs. It is possible to suppress an excessive increase in the amount of deformation of the actuator unit 60 without an excessively large area disposed at a certain position.

  The configuration in which the separation distance (d4 + d5) and the separation distance (D4 ′ + D5 ′) are different from each other as in the present embodiment is that the actuator unit is caused by contraction of the first active unit 61 when a positional deviation in the rotation direction occurs. This is particularly suitable when the amount of deformation of 60 is small. According to the present embodiment, when the positional deviation in the rotation direction occurs, the second active portion 62 together with the deformation amount of the deformation that bends downward so that the actuator portion 60 protrudes downward due to the contraction of the first active portion 61. Alternatively, it is possible to adjust the deformation amount of the deformation that is bent so as to protrude upward due to the contraction of the second active portion 63.

  For example, when the shape viewed from the Z direction is a circle, the first active portion 61 is located in the X direction of the first active portion 61 at a portion separated from the axis O in the Y direction when a rotational misalignment occurs. The distance in the X direction between the center 61 c of the pressure chamber 10 and the center of the pressure chamber 10 in the X direction is difficult to increase. Examples of the “shape of the first active portion 61 viewed from the Z direction” in which the decrease in the deformation amount of the actuator portion 60 due to the contraction of the first active portion 61 due to the displacement in the rotation direction is small. , A shape having square corners and curved corners and a large radius of curvature of the corners.

<Analysis results>
The inventor of the present application analyzed the head 3 (FIG. 5) according to the first embodiment under the following conditions.
The thickness of the piezoelectric layer 41 (length in the Z direction) = 15 μm
The thickness of the piezoelectric layer 42 (length in the Z direction) = 15 μm
The thickness of the piezoelectric layer 43 (length in the Z direction) = 13.3 μm
The thickness of the ink separation layer 44 (length in the Z direction) = 10 μm
・ Length of drive electrode 51 in X direction = 438 μm
The length of the high potential electrode 52 in the X direction (the length of the first active part 61 in the X direction) = 220 μm
-Length D of pressure chamber 10 in the X direction D = 340 μm
X from the other end 10b in the X direction of one of the two pressure chambers 10 (left pressure chamber 10 in FIG. 5) to one end 10a in the X direction of the other (right pressure chamber 10 in FIG. 5) Directional distance W = 84μm

  In FIGS. 10A and 10B, when the horizontal axis (distances d2 and d3) is positive, the second active portions 62 and 63 do not overlap with the pressure chamber 10 in the Z direction. When the horizontal axis (distances d2, d3) is zero, the other end 62b in the X direction of the second active part 62 and the one end 63a in the X direction of the second active part 63 are respectively one end 10a in the X direction of the pressure chamber 10 and It coincides with the other end 10b in the X direction. When the horizontal axis (distances d2 and d3) is negative, the second active portions 62 and 63 have portions that overlap the pressure chamber 10 in the Z direction.

  10A, when the distances d2 and d3 are 15 μm (that is, the separation distance (d4 + d5) is a length obtained by adding 30 μm to the length D in the X direction of the pressure chamber 10). It can be seen that the gradient of quantity turns from minus to plus. In addition, when the distances d2 and d3 are 15 μm or more and the positional deviation in the X direction between the flow path unit 21 and the piezoelectric actuator 22 occurs as shown in FIG. While the amount of deformation of the actuator unit 60 due to the contraction of the active portion 63 gradually decreases, the distance d2 decreases, so that the amount of deformation of the actuator unit 60 due to the contraction of the second active portion 62 increases greatly, and the actuator unit 60 as a whole. It can be seen that a decrease in the deformation amount is suppressed.

  Further, from FIG. 10A, it can be seen that the longer the distances d2 and d3, the lower the deformation amount of the actuator portion 60. When the distances d2 and d3 reach 50 μm, the deformation amount of the actuator portion 60 greatly decreases. . Therefore, from the viewpoint of securing the deformation amount of the actuator unit 60, the distances d2 and d3 are 70 (= 50 + 20), where the allowable value of the positional deviation amount in the X direction between the flow path unit 21 and the piezoelectric actuator 22 is 20 μm. It can be seen that it is preferable that the distance is not more than μm (that is, the separation distance (d4 + d5) is not more than a length obtained by adding 140 μm to the length D of the pressure chamber 10 in the X direction).

  From FIG. 10B, when the distances d2 and d3 are approximately 15 μm (that is, the separation distance (d4 + d5) is equal to the length D in the X direction of the pressure chamber 10 plus 30 μm), FIG. When the positional deviation in the X direction between the flow path unit 21 and the piezoelectric actuator 22 as shown (positional deviation amount = 20 μm) occurs, the deformation amount of the actuator unit 60 due to the contraction of the second active part 62 causes the positional deviation. It turns out that it increases compared with the case without.

  In FIG. 10C, the solid line shows the analysis result for the embodiment of the present invention (distances d2, d3 = 20 μm), and the broken line shows the analysis result for the comparative example (distances d2, d3 = 0 μm) of the present invention. . From FIG. 10 (c), the positional deviation in the X direction between the flow path unit 21 and the piezoelectric actuator 22 as shown in FIG. 7 occurs, and as the positional deviation amount increases, both the examples and the comparative examples are actuator sections. Although the deformation amount of 60 is reduced, it can be seen that the embodiment reduces the deformation amount of the actuator unit 60 more than the comparative example.

  In FIGS. 10B and 10C, the positional deviation amount means a distance in the X direction from the center 61 c in the X direction of the first active portion 61 to the center in the X direction of the pressure chamber 10.

<Modification>
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  For example, the configuration of the piezoelectric layer and the electrode in the piezoelectric actuator can be changed as follows. As the electrode arrangement is changed, the thickness (length in the Z direction) of the first active part 61 and the second active part 62, 63 and the positional relationship between the first active part 61 and the second active part 62, 63 in the Z direction. Can also change.

  In the first modification of FIG. 11A, the positions of the high potential electrode 52 and the low potential electrode 53 in the Z direction are opposite to those in the above-described embodiment. A drive electrode 51, a low potential electrode 53, and a high potential electrode 52 are arranged in this order from the top in the Z direction. The low potential electrode 53 is disposed between the piezoelectric layer 41 and the piezoelectric layer 42 in the Z direction. The high potential electrode 52 is disposed between the piezoelectric layer 42 and the piezoelectric layer 43 in the Z direction. The low potential electrode 53 is farther from the pressure chamber 10 in the Z direction than the high potential electrode 52.

  In the second modified example of FIG. 11B, the positions of the drive electrode 51 and the high potential electrode 52 in the Z direction are opposite to those in the above-described embodiment. In the Z direction, a high potential electrode 52, a drive electrode 51, and a low potential electrode 53 are arranged in order from the top. The high potential electrode 52 is disposed on the upper surface of the piezoelectric layer 41. The drive electrode 51 is disposed between the piezoelectric layer 41 and the piezoelectric layer 42 in the Z direction.

  In the third modified example of FIG. 11C, the number of piezoelectric layers is two. The piezoelectric body 40 has two piezoelectric layers 41 and 42 stacked in the Z direction. The high potential electrode 52 and the low potential electrode 53 are disposed between the piezoelectric layer 41 and the piezoelectric layer 42 (that is, the same layer) in the Z direction.

  In the fourth modification of FIG. 12A, the high potential electrode 52 extends to a position adjacent to the low potential electrode 53 in the X direction. Accordingly, the first active portion 61 is adjacent to the second active portions 62 and 63 without being separated from the second active portions 62 and 63 in the X direction.

  In the fifth modified example of FIG. 12B, as in the fourth modified example, the high potential electrode 52 extends to a position adjacent to the low potential electrode 53 in the X direction. Accordingly, the first active portion 61 is adjacent to the second active portions 62 and 63 without being separated from the second active portions 62 and 63 in the X direction. In the fifth modification, the low potential electrode 53 is further formed on the entire upper surface of the piezoelectric layer 43 and has a portion overlapping the high potential electrode 52 in the Z direction.

  In the sixth modified example of FIG. 12C, the drive electrode 51 is formed not only on the upper surface of the piezoelectric layer 41 but also on the upper surface of the piezoelectric layer 43. The high potential electrode 52 and the low potential electrode 53 are disposed between the piezoelectric layer 41 and the piezoelectric layer 42 (that is, the same layer) in the Z direction. Accordingly, the piezoelectric layers 41 and 42 are sandwiched between the drive electrode 51 and the low potential electrode 53 in the Z direction, respectively, in the first active portion 61 sandwiched between the drive electrode 51 and the high potential electrode 52 in the Z direction. Second active portions 62 and 63 are formed.

  The separation layer 44 may be omitted.

  The first portion may include a portion that does not overlap with the pressure chamber in the third direction (see FIGS. 12A and 12B). The first portion may include a portion adjacent to the second portion and / or the third portion in the first direction, and a portion overlapping the second portion and / or the third portion in the third direction.

  In a state where there is no displacement between the flow path unit and the piezoelectric actuator, the second portion may not overlap the pressure chamber in the third direction, and the third portion may overlap the pressure chamber in the third direction. Even in this case, when the positional deviation in the first direction occurs and the separation distance in the first direction from the pressure chamber of the second portion becomes shorter, or when the second portion overlaps the pressure chamber in the third direction, The amount of deformation of the actuator portion due to the contraction of the second portion is increased, and a decrease in the amount of deformation of the actuator portion can be suppressed.

  In the second embodiment, the separation distance between the second portion and the third portion in the first direction is locally at the boundary between the wide portion 254 and the narrow portion 255 or at the boundary between the wide portion 258 and the narrow portion 259. Although it has changed, the said separation distance may change gradually in a 2nd direction.

  The length of the pressure chamber in the first direction may be longer than the length in the second direction.

  The number of discharge ports and pressure chambers is 32 in the above-described embodiment, but is not limited thereto. For example, more than 32 outlets and pressure chambers may be provided.

  The liquid ejection head is not limited to ejecting one color ink, and may eject plural colors of ink.

  The liquid ejected by the liquid ejection head is not limited to ink, and may be any liquid (for example, a treatment liquid that aggregates or precipitates components in the ink).

  The liquid discharge head is not limited to a serial type, and may be a line type.

  The present invention is not limited to a printer, but can also be applied to a facsimile machine, a copier, a multifunction machine, and the like. The present invention is also applicable to a liquid ejecting apparatus used for purposes other than image recording (for example, a liquid ejecting apparatus that forms a conductive pattern by ejecting a conductive liquid onto a substrate).

1 Printer 3 Head (Liquid ejection head)
DESCRIPTION OF SYMBOLS 10 Pressure chamber 10a One end 10b Other end 15x Discharge port 21 Flow path unit 22 Piezoelectric actuator 22a One end 22b Other end 34x Discharge surface 40 Piezoelectric body 41-43 Piezoelectric layer 51 Drive electrode (1st electrode, 4th electrode)
52 High-potential electrodes (second electrode, fifth electrode)
53; 253 Low potential electrode (third electrode, sixth electrode)
60 Actuator part 61 1st active part (1st part, 4th part)
61c center 62 second active part (second part, fifth part)
62a one end 62b other end 63 2nd active part (3rd part, 6th part)

Claims (8)

A flow having a discharge surface parallel to a first direction and a second direction orthogonal to the first direction, the discharge surface being a surface defining a discharge port, and having a pressure chamber communicating with the discharge port. Road unit,
A piezoelectric actuator stacked on the flow path unit in a third direction orthogonal to the ejection surface;
The piezoelectric actuator is
A piezoelectric body having a plurality of piezoelectric layers stacked in the third direction;
A first electrode;
A second electrode spaced from the first electrode in the third direction;
A third electrode spaced apart from the first electrode in the third direction,
The piezoelectric body is
A first portion sandwiched between the first electrode and the second electrode in the third direction, the first portion having a portion overlapping the pressure chamber in the third direction;
A second portion sandwiched between the first electrode and the third electrode in the third direction;
A third portion sandwiched between the first electrode and the third electrode in the third direction, and a third portion spaced from the second portion in the first direction,
The first portion has a portion disposed between the second portion and the third portion in the first direction;
In the cross section along the first direction and the third direction passing through the pressure chamber, the first portion, the second portion, and the third portion, the second portion and the third portion in the first direction, The liquid discharge head is characterized in that the separation distance is longer than the length of the pressure chamber in the first direction.   The distance between the second portion and the third portion in the first direction in the cross section is 30 μm or more longer than the length of the pressure chamber in the first direction. Liquid discharge head. The first electrode is separated from the pressure chamber in the third direction than the second electrode and the third electrode,
3. The liquid ejection head according to claim 1, wherein the second electrode is separated from the pressure chamber in the third direction than the third electrode. 4. The separation distance in the cross-section;
Another cross section along the third direction and the third direction passing through the pressure chamber, the first portion, the second portion, and the third portion, and a position different from the cross section in the second direction. 4. The liquid ejection head according to claim 1, wherein the separation distances in different cross sections passing through are different from each other. 5. In the flow path unit, another pressure chamber separated from the pressure chamber in the first direction is formed,
The piezoelectric actuator is
A fourth electrode spaced from the first electrode in the first direction;
A fifth electrode spaced from the fourth electrode in the third direction;
A sixth electrode spaced apart from the fourth electrode in the third direction,
The piezoelectric body is
A fourth portion sandwiched between the fourth electrode and the fifth electrode in the third direction, the fourth portion having a portion overlapping the other pressure chamber in the third direction;
A fifth portion sandwiched between the fourth electrode and the sixth electrode in the third direction;
A sixth portion sandwiched between the fourth electrode and the sixth electrode in the third direction, and a sixth portion spaced from the fifth portion in the first direction;
The fourth portion has a portion disposed between the fifth portion and the sixth portion in the first direction;
In the cross section along the first direction and the third direction passing through the another pressure chamber, the fourth portion, the fifth portion, and the sixth portion, the fifth portion and the sixth portion in the first direction. The separation distance from the portion is longer than the length of the another pressure chamber in the first direction,
The third portion and the fifth portion are disposed between the first portion and the fourth portion in the first direction;
In a cross section along the first direction and the third direction passing through the third portion and the fifth portion, a separation distance between the third portion and the fifth portion in the first direction is 60 μm or more. The liquid ejection head according to claim 1, wherein the liquid ejection head is characterized in that:   6. The liquid ejection head according to claim 1, wherein a length of the pressure chamber in the first direction is 340 μm or less.   2. AL (Acoustic Length: 1/2 of an acoustic resonance period in the pressure chamber of a pressure wave generated in the pressure chamber due to deformation of the piezoelectric actuator) is 4.5 μs or less. The liquid discharge head according to any one of -6. A flow having a discharge surface parallel to a first direction and a second direction orthogonal to the first direction, the discharge surface being a surface defining a discharge port, and having a pressure chamber communicating with the discharge port. Road unit,
A piezoelectric actuator stacked on the flow path unit in a third direction orthogonal to the ejection surface;
The piezoelectric actuator is
A piezoelectric body having a plurality of piezoelectric layers stacked in the third direction;
A first electrode;
A second electrode spaced from the first electrode in the third direction;
A third electrode spaced apart from the first electrode in the third direction,
The piezoelectric body is
A first portion sandwiched between the first electrode and the second electrode in the third direction, the first portion having a portion overlapping the pressure chamber in the third direction;
A second portion sandwiched between the first electrode and the third electrode in the third direction;
A third portion sandwiched between the first electrode and the third electrode in the third direction, and a third portion spaced from the second portion in the first direction,
The first portion has a portion disposed between the second portion and the third portion in the first direction;
The piezoelectric actuator has one end in the first direction and the other end in the first direction,
The pressure chamber has one end in the first direction and the other end in the first direction;
The other end of the pressure chamber is located between the one end of the pressure chamber and the other end of the piezoelectric actuator in the first direction;
The second portion has one end in the first direction and the other end in the first direction,
The other end of the second portion is located between the one end of the second portion and the other end of the piezoelectric actuator in the first direction;
The other end of the second portion and the one end of the pressure chamber are located between the one end of the piezoelectric actuator and a center of the first portion in the first direction in the first direction, The distance in the first direction from the other end of the two portions to the center of the first portion is less than half of the distance in the first direction from the one end of the pressure chamber to the other end of the pressure chamber. A liquid discharge head characterized by its long length.

Images