JP7106938B2 - liquid ejection head - Google Patents

Description

The present invention relates to a liquid ejection head including a channel unit and a piezoelectric actuator stacked on the channel unit.

FIG. 8 of Patent Document 1 shows a channel unit having a discharge surface parallel to the X direction (first direction) and the Y direction (second direction), and a channel unit stacked in the Z direction (third direction). and a piezoelectric actuator. The piezoelectric actuator includes a first active portion that overlaps the pressure chamber of the channel 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 a 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 between 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 channel unit, if a positional deviation occurs between the channel unit and the piezoelectric actuator in the X direction, the actuator section composed of the first active portion and the two second active portions will be deformed. The amount of deformation can be reduced compared to when there is no misalignment. In the configuration of FIG. 8 of Patent Document 1, in a 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 between the two second active portions is Since it is the same as the length of the pressure chamber in the X direction, as will be apparent from the analysis results described later, the amount of deformation of the actuator section is greatly reduced due to the positional deviation between the channel unit and the piezoelectric actuator.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid ejection head capable of suppressing a decrease in the amount of deformation of an actuator section due to a positional deviation between a channel unit and a piezoelectric actuator.

A liquid ejection head according to a first aspect of the present invention has an ejection surface parallel to a first direction and a second direction perpendicular to the first direction, the ejection surface defining an ejection port, A channel unit in which a pressure chamber communicating with the ejection port is formed; and a piezoelectric actuator stacked on the channel unit in a third direction orthogonal to the ejection surface, wherein the piezoelectric actuator A piezoelectric body having a plurality of piezoelectric layers laminated in three directions, a first electrode, a second electrode separated from the first electrode in the third direction, and a second electrode separated from the first electrode in the third direction. and a third electrode, wherein the piezoelectric body is a first portion sandwiched between the first electrode and the second electrode in the third direction and 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; and a portion sandwiched between the first electrode and the third electrode in the third direction a third portion spaced apart from the second portion in the first direction, wherein the first portion is located between the second portion and the third portion in the first direction; in the first direction in a 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 and having a portion disposed therebetween A separation distance between the second portion and the third portion is longer than a length of the pressure chamber in the first direction, and the channel unit is provided with another pressure spaced apart from the pressure chamber in the first direction. A chamber is formed, and the piezoelectric actuator includes a fourth electrode spaced from the first electrode in the first direction, a fifth electrode spaced from the fourth electrode in the third direction, and a fourth electrode spaced from the fourth electrode in the third direction. and a sixth electrode separated from the fourth electrode in the third direction, wherein the piezoelectric body is a fourth portion sandwiched between the fourth electrode and the fifth electrode in the third direction, the third a fourth portion having a portion overlapping the another pressure chamber in the direction; a fifth portion sandwiched between the fourth electrode and the sixth electrode in the third direction; and the fourth electrode in the third direction. and the sixth electrode, the sixth portion being separated from the fifth portion in the first direction, wherein the fourth portion is located in the first direction having a portion located between said fifth portion and said sixth portion, passing through said further pressure chamber, said fourth portion, said fifth portion and said sixth portion; In a cross section along the first direction and the third direction, the separation distance between the fifth portion and the sixth portion in the first direction is longer than the length of the another pressure chamber in the first direction. , wherein the third portion and the fifth portion are arranged between the first portion and the fourth portion in the first direction .
A liquid ejection head according to a second aspect of the present invention has an ejection surface parallel to a first direction and a second direction orthogonal to the first direction, the ejection surface being a surface defining ejection ports, A channel unit in which a pressure chamber communicating with the ejection port is formed; and a piezoelectric actuator stacked on the channel unit in a third direction orthogonal to the ejection surface, wherein the piezoelectric actuator A piezoelectric body having a plurality of piezoelectric layers laminated in three directions, a first electrode, a second electrode separated from the first electrode in the third direction, and a second electrode separated from the first electrode in the third direction. and a third electrode, wherein the piezoelectric body is a first portion sandwiched between the first electrode and the second electrode in the third direction and 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; and a portion sandwiched between the first electrode and the third electrode in the third direction a third portion spaced apart from the second portion in the first direction, wherein the first portion is located between the second portion and the third portion in the first direction; in the first direction in a 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 and having a portion disposed therebetween A separation distance between the second portion and the third portion is longer than a length of the pressure chamber in the first direction, and the separation distance in the cross section is the same as the pressure chamber, the first portion, and the second portion. and another cross section along the first direction and the third direction passing through the third portion, the separation distance in another cross section passing through a position different from the cross section in the second direction, characterized by being different from each other.

A liquid ejection head according to a third aspect of the present invention has an ejection surface parallel to a first direction and a second direction perpendicular to the first direction, the ejection surface defining an ejection port, A channel unit in which a pressure chamber communicating with the ejection port is formed; and a piezoelectric actuator stacked on the channel unit in a third direction orthogonal to the ejection surface, wherein the piezoelectric actuator A piezoelectric body having a plurality of piezoelectric layers laminated in three directions, a first electrode, a second electrode separated from the first electrode in the third direction, and a second electrode separated from the first electrode in the third direction. and a third electrode, wherein the piezoelectric body is a first portion sandwiched between the first electrode and the second electrode in the third direction and 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; and a portion sandwiched between the first electrode and the third electrode in the third direction a third portion spaced apart from the second portion in the first direction, wherein the first portion is located 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 in the first direction, the other end of the pressure chamber being positioned between the one end of the pressure chamber and the other end of the piezoelectric actuator in the first direction; The two portions have one end in the first direction and the other end in the first direction, and the other end of the second portion is located in the first direction with the one end of the second portion and the The other end of the second portion and the one end of the pressure chamber are positioned between the other end of the piezoelectric actuator and the first end of the first portion in the first direction. and the distance in the first direction from the other end of the second portion to the center of the first portion is the distance from the one end of the pressure chamber to the other of the pressure chambers. Another pressure chamber is formed in the flow channel unit and is separated from the pressure chamber in the first direction, and the piezoelectric actuator is arranged to move the piezoelectric actuator to the first direction. a fourth electrode separated from the first electrode in one direction; a fifth electrode separated from the fourth electrode in the third direction; and a fourth electrode separated from the fourth electrode in the third direction. and a sixth electrode, wherein the piezoelectric body is a fourth portion sandwiched between the fourth electrode and the fifth electrode in the third direction, and the pressure chamber is located in the third direction. a fifth portion sandwiched between the fourth electrode and the sixth electrode in the third direction; and between the fourth electrode and the sixth electrode in the third direction. a sandwiched sixth portion spaced apart from the fifth portion in the first direction, wherein the fourth portion is located between the fifth portion and the fourth portion in the first direction; 6, the another pressure chamber has one end in the first direction and the other end in the first direction, the other pressure chamber of the another pressure chamber The end is positioned between the one end of the another pressure chamber and the other end of the piezoelectric actuator in the first direction, and the fifth portion is located between the one end in the first direction and the first direction. and the other end of the fifth portion is located between the one end of the fifth portion and the other end of the piezoelectric actuator in the first direction, and the fifth The other end of the portion and the one end of the another pressure chamber are positioned between the one end of the piezoelectric actuator and the center of the fourth portion in the first direction in the first direction, The distance in the first direction from the other end of the portion to the center of the fourth portion is the distance in the first direction from the one end of the another pressure chamber to the other end of the another pressure chamber. It is characterized in that the third part and the fifth part are arranged between the first part and the fourth part in the first direction and are longer than half .

According to a first aspect of the present invention, "in a cross section along the first direction and the third direction passing through the pressure chamber, the first part, the second part and the third part, the second part and the third part in the first direction is longer than the length of the pressure chamber in the first direction". A second aspect of the present invention is that ``the distance in the first direction from the other end of the second portion to the center of the first portion is more than half the distance in the first direction from one end of the pressure chamber to the other end of the pressure chamber. also long". In the configuration that satisfies the requirements of the first aspect, when a displacement occurs in the first direction between the channel unit and the piezoelectric actuator, the amount of deformation of the actuator section due to contraction of one of the second portion and the third portion is increased, and a decrease in the amount of deformation of one actuator unit as a whole is suppressed. In the configuration that satisfies the requirements of the second aspect, a positional deviation occurs in the first direction between the channel unit and the piezoelectric actuator, and the separation distance in the first direction from the pressure chamber of the second portion is shortened. Alternatively, 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 increases, and a decrease in the amount of deformation of the entire actuator portion is suppressed. That is, by satisfying any one of the above requirements, it is possible to suppress a decrease in the amount of deformation of the actuator section due to positional deviation.

According to the present invention, it is possible to suppress a decrease in the amount of deformation of the actuator section due to a positional deviation between the channel unit and the piezoelectric actuator.

1 is an overall configuration diagram of a printer including a head according to a first embodiment of the invention; FIG. 2 is a plan view of the head of FIG. 1; FIG. 3A is a plan view showing the upper surface of each of the three piezoelectric layers in the piezoelectric actuator of FIG. 2, where (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. 2 shows the top surface of the piezoelectric layer. FIG. 4 is a cross-sectional view taken along line IV-IV of FIGS. 2 and 3; 4 is a cross-sectional view taken along line VV of FIGS. 2 and 3; FIG. 6 is an enlarged view of area VI in FIG. 5 showing the operation of the actuator section; FIG. FIG. 7 is a diagram corresponding to FIG. 6 and showing the operation of the actuator unit when a positional deviation in the X direction occurs; It is a top view equivalent to FIG.3(c) in the head based on 2nd Embodiment of this invention. 9A and 9B are enlarged views of one actuator unit corresponding to the region IX of FIG. 8, where (a) shows a state without positional deviation, and (b) shows a state where positional deviation occurs in the rotational direction; It is a graph which shows an analysis result. 6A to 6C are diagrams corresponding to area VI in FIG. 5 of heads according to first, second and third modifications of the present invention, respectively; FIG. 6A to 6C are diagrams corresponding to area VI in FIG. 5 of heads according to fourth, fifth and sixth modifications of the present invention, respectively; FIG.

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

In the following description, the Z direction is the vertical direction, and the X and Y directions are the horizontal directions. Both the X and Y directions 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 to the second direction, and the Z direction to the third direction.

The printer 1 has 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 along the guide rails 5 in the Y direction.

The head 3 is of a serial type, is mounted on the carriage 2, and is movable together with the carriage 2 in the Y direction. Thirty-two ejection ports 15x are opened on the lower surface of the head 3 (the surface facing downward in the Z direction). The lower surface of the head 3 is an ejection surface 34x defining 32 ejection openings 15x (see FIG. 4). The ejection surface 34x is parallel to the X and Y directions and orthogonal to the Z direction.

The two transport roller pairs 4 are arranged across the carriage 2 in the X direction. As the transport roller pair 4 rotates while nipping the paper P, the paper P is transported in the transport direction along the X direction.

A control unit (not shown) of the printer 1 moves the head 3 along with the carriage 2 in the Y direction while ejecting ink from the ejection port 15x, and transports the paper P by a predetermined amount in the transport direction with the transport roller pair 4. The conveying operation is performed alternately. Thus, an image is recorded on the paper P. FIG.

Next, the configuration of the head 3 will be described with reference to FIGS. 2 to 5. FIG.

The head 3 has a channel unit 21, a piezoelectric actuator 22 and a COF (Chip On Film) 23, as shown in FIG.

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

The channel unit 21 has four plates 31 to 34 stacked in the Z direction, as shown in FIG.

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

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

A through hole 14 is formed in each through hole 13 in the plate 33 . 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 respectively correspond to the four pressure chamber rows 9, as shown in FIG. Each manifold channel 11 extends in the X direction and has a portion overlapping with the eight pressure chambers 10 of the corresponding pressure chamber row 9 in the Z direction.

Four ink supply ports 8 are formed on the upper surface of the plate 31 in areas where the piezoelectric actuators 22 are not arranged. Each of the four ink supply ports 8 is located at a position overlapping in the Z direction with one end (lower end in FIG. 2) of the four manifold channels 11 in the X direction. Ink is supplied to each of the four manifold channels 11 from the four ink supply ports 8 .

32 nozzles 15 are formed in the plate 34 . Each of the 32 nozzles 15 overlaps 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 through the through holes 12 . Each of the pressure chambers 10 communicates with the outlet 15x of the nozzle 15 through the through holes 13 and 14. As shown in FIG.

The piezoelectric actuator 22 is stacked on the channel unit 21 in the Z direction and arranged on the upper surface of the plate 31, as shown in FIG.

The piezoelectric actuator 22 has 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 laminated in the Z direction. The piezoelectric layers 41 to 43 and the ink separation layer 44 have the same shape and size in the plane along the X direction and the Y direction, and as shown in FIG. is defined.

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

The piezoelectric layer 43 is arranged on the upper surface of the ink separation layer 44 . The piezoelectric layer 42 is arranged on the upper surface of the piezoelectric layer 43 . The piezoelectric layer 41 is arranged on the upper surface of the piezoelectric layer 42 . The piezoelectric layers 41 to 43 each overlap the ink separation layer 44 in the Z direction. The piezoelectric layers 41 to 43 are made of a piezoelectric material containing lead zirconate titanate as a main component.

The 32 driving electrodes 51, the high-potential electrodes 52, and the low-potential electrodes 53 are different in position in the Z direction. Specifically, 32 drive electrodes 51, high-potential electrodes 52, and low-potential electrodes 53 are arranged in order from the top in the Z direction. The 32 drive electrodes 51 are further apart from the pressure chambers 10 in the Z direction than the high potential electrodes 52 and the low potential electrodes 53 . The high potential electrode 52 is further away from the pressure chamber 10 in the Z direction than the low potential electrode 53 is. The high potential electrodes 52 and the low potential electrodes 53 are each separated from the 32 drive electrodes 51 in the Z direction.

In this embodiment, there is no positional deviation between the channel unit 21 and the piezoelectric actuator 22, and the electrodes and active portions of the piezoelectric actuator 22 and the pressure chambers 10 of the channel unit 21, which will be described below, are not displaced. The positional relationship of is for the case where there is no positional deviation.

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

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 through 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 arranged between the piezoelectric layers 41 and 42 in the Z direction.

As shown in FIG. 3B, the high potential electrode 52 has 32 individual portions 52a, four connection portions 52b, a connection portion 52c and a lead portion 52d. The 32 individual portions 52a overlap in the Z direction with the respective center portions in the X direction of the pressure chambers 10 formed in the plate 31 . 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 (right end in FIG. 3B) of the individual portion 52a in the Y direction corresponding to each of the eight pressure chambers 10 of the pressure chamber row 9. there is The connecting portion 52c extends in the Y direction and connects one ends (lower ends in FIG. 3B) of the four connecting portions 52b in the X direction. The lead-out portion 52d extends from the other Y-direction end of the connection portion 52c (the left end in FIG. 3B) from the one X-direction end 22a of the piezoelectric actuator 22 toward the other X-direction end 22b. 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 via a through hole 41x (see FIG. 3A) formed in the piezoelectric layer 41. As shown in FIG. The surface electrode 72 is arranged on the upper surface of the piezoelectric layer 41 so as to overlap with 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 arranged between the piezoelectric layers 42 and 43 in the Z direction.

As shown in FIG. 3(c), the low potential electrode 53 has 32 individual portions 53a, four connection portions 53b, a connection portion 53c and a lead portion 53d. The 32 individual portions 53a are arranged at positions adjacent to the respective pressure chambers 10 formed in the plate 31 in the X direction and not overlapping in the Z direction. An individual portion 53a is arranged between two pressure chambers 10 adjacent to each other in the X direction. Further, an individual portion 53a is arranged between one end 22a of the piezoelectric actuator 22 in the X direction and the pressure chamber 10 adjacent to the 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 (the left ends in FIG. 3C) of the individual portions 53a in the Y direction corresponding to the eight pressure chambers 10 of the pressure chamber row 9. ing. The connecting portion 53c extends in the Y direction and connects the other ends in the X direction (upper ends in FIG. 3C) of the four connecting portions 53b. The lead-out portion 53d extends from the other Y-direction end of the connection portion 53c (the left end in FIG. 3C) from the other X-direction end 22b of the piezoelectric actuator 22 toward the X-direction end 22a. 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 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 formed in the piezoelectric layer 42 (see FIG. 3B). It is connected. The surface electrode 73 is arranged 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 .

By arranging the electrodes 51 to 53 as described above, among the 32 drive electrodes 51, the drive electrodes 51 except for the four drive electrodes 51 located at the other end in the X direction (upper end in FIG. 3A) are As shown in FIG. 5, the central portion of the main portion 51a in the X direction overlaps the individual portion 52a of the high potential electrode 52 in the Z direction, and the low potential electrode 53 overlaps with both ends of the main portion 51a in the X direction. It overlaps with the individual portion 53a in the Z direction. Each of the four drive electrodes 51 overlaps the individual portion 52a of the high-potential electrode 52 in the Z-direction at the central portion of the main portion 51a in the X direction, and overlaps the low-potential electrode 53 at one end of the main portion 51a in the X-direction. 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 of the main portion 51a in the X direction.

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 called "second active portions 62 and 63". The first active portion 61 is polarized primarily upward, and the second active portions 62, 63 are polarized primarily downward.

In this embodiment, the drive electrode 51 corresponds to the "first electrode", the high potential electrode 52 corresponds to the "second electrode", and the low potential electrode 53 corresponds to the "third electrode". The first active portion 61 corresponds to the 'first portion', the second active portion 62 corresponds to the 'second portion', and the second active portion 63 corresponds to the 'third portion'.

The piezoelectric actuator 22 has an actuator section 60 composed of one first active section 61 and two second active sections 62 and 63 for each pressure chamber 10 . Here, the second active portions 62 and 63 have a function of suppressing crosstalk. Crosstalk is a phenomenon in which pressure fluctuations caused by deformation of the actuator section 60 in a pressure chamber 10 are transmitted to another pressure chamber 10 adjacent to the pressure chamber 10 in the X direction.

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

FIG. 5 is a diagram along the X and Z directions passing through 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.

5, the positional relationship between the active portions 61 to 63 in one actuator portion 60, the active portions 61 to 63 in one actuator portion 60, and the corresponding The positional relationship and the like with one pressure chamber 10 will be described.

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

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

The second active portions 62 and 63 do not overlap the pressure chambers 10 in the Z direction. The second active portion 62 is positioned in the X direction between one end 10a of the pressure chamber 10 in the X direction (the left end in FIG. 5) and one end 22a of the piezoelectric actuator 22 in the X direction (see FIG. 3). The second active portion 63 is positioned in the X direction 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). . The other end 10b is positioned 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 ends of the pressure chamber 10 and the active portions 61 to 63 in the X direction is as follows.

One end 61a and the other end 61b of the first active portion 61 in the X direction are located between the one end 10a and the other end 10b 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.

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

One end 63a and the other end 63b of the second active portion 63 in the X direction are located between the other end 10b of the pressure chamber 10 in the X direction and the other end 22b 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 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 channel unit 21 and the piezoelectric actuator 22 No deviation occurred. 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 distance d2 in the X direction from the other end 10b in the X direction of the pressure chamber 10 to the second active portion 63 are the same as each other.

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 arranged so that the one end 22a in the X direction of the piezoelectric actuator 22 and the center 61c in the X direction of the first active portion 61 are in the X direction. located between 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 one end 10a to the other end 10b).

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

The distances d4 and d5 are the same because the second active portions 62 and 63 are arranged symmetrically with respect to the Z-direction axis passing through the center 61c.

In a cross section along the X and Z directions 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 A separation distance (d4+d5) between the active portion 62 and the second active portion 63 is longer than the length D of the pressure chamber 10 in the X direction. The separation distance (d4+d5) is, in other words, the distance in the X direction from the other end 62b of the second active portion 62 in the X direction to the one end 63a of the second active portion 63 in the X direction.

The separation distance (d4+d5) is, for example, when the X-direction length D of the pressure chamber 10 is 340 μm, the X-direction length D of the drive electrode 51 is 438 μm, and the X-direction length of the first active portion 61 is 220 μm, Based on the analysis results described later, it is preferable that the length is equal to or greater than the length D plus 30 μm and equal to or less than the length D plus 140 μm. That is, the distances d2 and d3 are preferably 15 μm or more and 70 μm or less.

Furthermore, referring to FIG. 5, the positional relationship between the active portions 61 to 63 of the actuator section 60 provided for two pressure chambers 10 adjacent to each other in the X direction will be described.

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

As for the separation distance d1 between the active portions 63 and 62, for example, the length D in the X direction of the pressure chamber 10 is 340 μm, the length in the X direction of the drive electrode 51 is 438 μm, and the length in the X direction of the first active portion 61 is 220 μm, from the other end 10b in the X direction of one of the two pressure chambers 10 (the left pressure chamber 10 in FIG. 5) to the one end 10a in the X direction of the other (the 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 forming the active portions 63 and 62 . The separation distance d1 is along the X and Z directions 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 a cross section (that is, a cross section orthogonal to the Y direction: see FIG. 5), the separation in the X direction between the second active portion 63 provided on one side and the second active portion 62 provided on the other side. Distance. In other words, the separation distance d1 is from the other end 63b in the X direction of the second active portion 63 provided for one of the two pressure chambers 10 to the second active portion 62 provided for the other. It is the distance in the X direction to one end 62a in the X direction.

Next, with reference to FIG. 6, the operation of the actuator section 60 corresponding to the ejection port 15x when ink is ejected from the ejection port 15x will be described.

Before the printer 1 starts the recording operation, a low potential (GND potential) is applied to the 32 driving electrodes 51 as shown in FIG. 6(a). At this time, in each of the 32 actuator sections 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 section 61, and the first active section 61 becomes plane. It shrinks in the directions (directions along the X and Y directions). 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 bends so as to protrude toward the pressure chamber 10 (downward). At this time, the volume of the pressure chamber 10 is smaller than when the laminate is flat.

When the printer 1 starts a recording operation and ejects ink from a certain ejection port 15x, first, as shown in FIG. GND potential) to a high potential (VDD potential). At this time, the potential difference between the drive electrode 51 and the high-potential electrode 52 disappears in the actuator section 60, so that the contraction of the first active section 61 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the low potential electrode 53, 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 planar direction. . However, the second active portions 62 and 63 have the crosstalk suppressing function as described above, and contribute substantially to the deformation of the actuator portion 60 when there is no positional deviation between the channel unit 21 and the piezoelectric actuator 22. do not do. In other words, at this time, the laminate is in a flat state without flexing such that the portion overlapping the pressure chamber 10 in the Z direction is convex (upward) in the direction away from the pressure chamber 10 . As a result, the volume of the pressure chamber 10 becomes larger than that in FIG. 6(a).

After that, 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, the potential difference between the drive electrode 51 and the low potential electrode 53 disappears in the actuator section 60, so that the contraction of the second active sections 62 and 63 is eliminated. On the other hand, the potential difference between the drive electrode 51 and the high potential electrode 52 causes an upward electric field equal to the polarization direction to occur in the first active portion 61, causing the first active portion 61 to contract in the planar direction. As a result, the portion of the laminate that overlaps the pressure chamber 10 in the Z direction bends so as to protrude 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 this 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 section 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.

6A and 6B are diagrams for explaining the operation of one actuator section 60 when there is no positional deviation between the channel unit 21 and the piezoelectric actuator 22. FIG. On the other hand, for example, when there is a positional deviation in the X direction as shown in FIG. 7, the amount of deformation of one actuator section 60 decreases to some extent.

In FIG. 7, part of the second active portion 62 overlaps the pressure chamber 10 in the Z direction. That is, the second active portion 62 includes a portion overlapping the pressure chamber 10 in the Z direction and a portion not overlapping the pressure chamber 10 in the Z direction. The second active portion 63 has a longer separation distance in the X direction from the pressure chamber 10 than in FIG. That is, the distance d3 in the X direction from the other end 10b (the right end in FIG. 7) of the pressure chamber 10 in the X direction to the one end 63a of the second active portion 63 in the X direction is longer than that in FIG. However, even if such a positional deviation occurs in the X direction, there is a 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 The requirement that D is greater than half the length D is satisfied.

In the example of FIG. 7, similarly to FIG. 6, the contraction of the first active portion 61 (FIG. 7A) and the contraction of the second active portions 62 and 63 (FIG. (b)) occur sequentially. However, compared to the case where there is no positional deviation (FIG. 6), the amount of deformation of the actuator section 60 due to the contraction of the first active portion 61 becomes smaller, and the deformation amount of the actuator portion 60 is reduced so that the second active portion 62 contracts. The amount of deformation of the actuator portion 60 that bends upward due to is increased. That is, the amount of deformation of one actuator section 60 when there is a positional deviation in the X direction is reduced by the amount of deformation of the actuator section 60 due to the contraction of the first active section 61, and the amount of deformation of one actuator when there is no positional deviation is reduced. Although the amount of deformation of the actuator section 60 is lower than that of the portion 60, the amount of deformation of the actuator section 60 due to the contraction of the second active section 62 increases (see FIG. 7(b)). Decrease is suppressed.

That is, according to the present embodiment, there is a requirement that the separation distance (d4+d5) is longer than the length D of the pressure chamber 10 in the X direction, and that the distances d4 and d5 are longer than half the length D of the pressure chamber 10 in the X direction. By satisfying the requirement that the distance is long, the amount of deformation of the actuator section 60 when there is no positional deviation is intentionally made smaller than when the above requirement is not met. When there is a positional deviation in the X direction, the amount of deformation of the actuator section 60 due to the contraction of one of the second active sections 62 and 63 increases, and the reduction in the amount of deformation of the entire actuator section 60 is suppressed. be done. That is, by satisfying the above requirements, it is possible to suppress a decrease in the amount of deformation of the actuator section 60 due to positional deviation in the X direction.

The separation distance (d4+d5) is preferably longer than the length D of the pressure chamber 10 in the X direction by 30 μm or more. This is because, as will be understood from the analysis results to be described later, a reduction in the amount of deformation of the actuator section 60 due to positional deviation in the X direction can be more reliably suppressed.

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

In the present embodiment, the driving 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 correspond to "first electrode", "second electrode", "third electrode", "first portion", "second portion" and "third portion", respectively. 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 pressure chamber 10 on the right side of FIG. 4 electrodes,” “fifth electrode,” “sixth electrode,” “fourth portion,” “fifth portion,” and “sixth portion.” 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. And in a 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 of the pressure chamber 10 in the X direction is preferably 340 μm or less. The shorter the length D, the higher the density of the pressure chambers 10 can be arranged. obtain. In this regard, according to the present embodiment, since it is possible to suppress a decrease in the amount of deformation of the actuator section 60 due to the positional deviation in the X direction between the channel unit 21 and the piezoelectric actuator 22, the length D is shortened and the pressure chamber A high density arrangement of 10 is 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 section 60) is 4.5 μs or less. As AL becomes shorter, the driving frequency of the piezoelectric actuator 22 can be increased. On the other hand, the shorter the length D of the pressure chambers 10, the shorter the AL. A decrease in the amount of deformation of the actuator section 60 can become significant. In this respect, according to the present embodiment, it is possible to suppress a decrease in the amount of deformation of the actuator section 60 due to the positional deviation in the X direction between the channel unit 21 and the piezoelectric actuator 22. Driving frequency can be increased.

<Second embodiment>
Next, a head according to a second embodiment of the invention will be described with reference to FIGS. 8 and 9. FIG. This embodiment differs from the first embodiment in the configuration of 32 individual portions 253a and connection portions 253c in the low potential electrode 253. FIG.

In this embodiment, the 32 individual portions 253a each have a wide portion 254 and a narrow portion 255 aligned in the Y direction, as shown in FIG. The wide portion 254 is arranged between the connecting 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 greater than the width of the narrow portion 255 . The X-direction center of the wide portion 254 and the X-direction center of the narrow portion 255 match in the X direction. Therefore, 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 (lower end in FIG. 8). The four recesses 257 correspond to the four pressure chamber rows 9 respectively. Each recess 257 is positioned to overlap the narrow width portion 255 corresponding to the pressure chamber row 9 in the X direction. The connecting portion 253 c has a wide portion 258 and narrow portions 259 corresponding to the recesses 257 . The width of the wide portion 258 (the length in the X direction) is greater than the width of the narrow portion 259 .

With such a configuration of the low potential electrode 253, in this embodiment, as shown in FIG. and wide portion 254 or wide portion 258, and portions 62y and 63y sandwiched between driving electrode 51 and narrow portion 255 or narrow portion 259 in the Z direction. The width of portion 62x is greater than the width of portion 62y. The width of portion 63x is greater than the width of portion 63y. The width of portion 62x is the same as the width of portion 63x. The width of portion 62y is the same as the width of portion 63y.

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

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

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

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

In FIG. 9(b), the first active portion 61 is located in the X direction between the center 61c in the X direction of the first active portion 61 and the center in the X direction of the pressure chamber 10 as the portion of the first active portion 61 is further away from the axis O in the Y direction. distance is increasing. In the portion 62x of the second active portion 62, the distance d2 is shorter as the portion is further away from the axis O in the Y direction than in FIG. 9A. The other end of the portion 62x in the Y direction (the left end in FIG. 9B) overlaps the pressure chamber 10 in the Z direction. The portion 62y has a longer distance d2' as the portion is more distant from the axis O in the Y direction than in FIG. 9(a). A portion 63x of the second active portion 63 has a longer distance d3 as compared to FIG. In the portion 63y, the distance d3' becomes shorter as the portion is more distant from the axis O in the Y direction than in FIG. 9(a).

In this case, the amount of contraction of the first active portion 61 decreases as the distance from the axis O in the Y direction increases, and the amount of deformation of the actuator portion 60 due to the contraction decreases. The second active portions 62 and 63 have portions 62y and 63x where the separation distance from the pressure chamber 10 in the X direction increases. The amount of deformation of the actuator section 60 due to the contraction of this portion is smaller than when there is no positional deviation in the rotational direction, as will be understood from the analysis results 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 short and portions overlapping the pressure chamber 10 in the Z direction. The amount of deformation of the actuator section 60 due to the contraction of the relevant portion is greater than when there is no positional deviation in the rotational direction, as will be understood from the analysis results described later. That is, the amount of deformation of one actuator portion 60 when there is a positional deviation in the rotational direction is the amount of deformation of the actuator portion 60 due to the contraction of the first active portion 61 and the contraction of the portions 62y and 63x of the second active portions 62 and 63. , the amount of deformation of the actuator section 60 becomes smaller than the amount of deformation of one actuator section 60 when there is no positional deviation in the rotational direction. Since the amount of deformation of the actuator section 60 due to is increased, the decrease in the amount of deformation of the entire actuator section 60 is suppressed.

Further, 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 are different from each other). 2, the separation distance from the active portion 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), as shown in FIG. If such a positional deviation occurs in the rotational direction, not only the portion 62x but also the portion 63y will be located at a position where the separation distance from the pressure chamber 10 in the X direction is equal to or less than a predetermined distance (for example, a position overlapping the pressure chamber 10 in the Z direction). ). In other words, when the separation distance is constant in the Y direction, the separation distance from the pressure chamber 10 increases in the second active portions 62 and 63 compared to the case where the separation distance is not constant in the Y direction. The area arranged at the position where the distance is equal to or less than the predetermined distance becomes large, and the amount of deformation of the actuator section 60 may become excessively large. 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 in the second active portions 62 and 63 is equal to or less than the predetermined distance even if a positional shift occurs in the rotational direction. Since the area arranged at the position where the actuator portion 60 is located does not become too large, it is possible to suppress the amount of deformation of the actuator section 60 from becoming excessively large.

In 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, the actuator unit is caused by contraction of the first active portion 61 when a positional deviation occurs in the rotational direction. It is particularly suitable when the deformation amount of 60 is small. According to the present embodiment, when a positional deviation occurs in the rotational direction, the amount of deformation of the actuator section 60 due to the contraction of the first active section 61 causes the actuator section 60 to bend downwardly, and the second active section 62 Alternatively, it is possible to adjust the amount of deformation of the actuator section 60 due to the contraction of the second active section 63 so that the actuator section 60 bends upwardly.

For example, when the first active portion 61 has a circular shape as viewed in the Z direction, when a positional deviation occurs in the rotational direction, a portion spaced apart from the axis O in the Y direction in the X direction of the first active portion 61 The distance in the X direction between the center 61c of the pressure chamber 10 and the center in the X direction of the pressure chamber 10 is difficult to increase. The “shape of the first active portion 61 viewed from the Z direction” that reduces the amount of deformation of the actuator portion 60 due to shrinkage of the first active portion 61 due to positional displacement in the rotational direction may be circular or elliptical. , a square, and a shape having curved corners with a large radius of curvature at the corners.

<Analysis result>
The inventor of the present application analyzed the head 3 (FIG. 5) according to the first embodiment under the following conditions.
・Thickness of piezoelectric layer 41 (length in Z direction)=15 μm
・Thickness of piezoelectric layer 42 (length in Z direction)=15 μm
・Thickness of piezoelectric layer 43 (length in Z direction)=13.3 μm
・Thickness of ink separation layer 44 (length in Z direction)=10 μm
・Length of drive electrode 51 in X direction=438 μm
・Length in the X direction of the high-potential electrode 52 (length in the X direction of the first active portion 61)=220 μm
・The length of the 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=84 μm

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

10A, when the distances d2 and d3 are 15 μm (that is, the distance (d4+d5) is the length of the pressure chamber 10 in the X direction plus 30 μm), deformation of the actuator section 60 It can be seen that the gradient of the quantity turns from negative to positive. Further, when the distances d2 and d3 are 15 μm or more, if a positional deviation occurs between the channel unit 21 and the piezoelectric actuator 22 in the X direction as shown in FIG. While the amount of deformation of the actuator section 60 due to the contraction of the active portion 63 gradually decreases, the decrease in the distance d2 greatly increases the amount of deformation of the actuator section 60 due to the contraction of the second active portion 62, and the entire actuator portion 60 It can be seen that the decrease in the amount of deformation as is suppressed.

Further, from FIG. 10A, it can be seen that the longer the distances d2 and d3, the more the amount of deformation of the actuator section 60 decreases, and when the distances d2 and d3 reach 50 μm, the amount of deformation of the actuator section 60 significantly decreases. . Therefore, from the viewpoint of securing the amount of deformation of the actuator section 60, the distances d2 and d3 are 70 (=50+20), assuming that the allowable value for the amount of positional deviation in the X direction between the channel unit 21 and the piezoelectric actuator 22 is 20 μm. It can be seen that it is preferable that the separation distance (d4+d5) be equal to or less than the 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 or more (that is, the separation distance (d4+d5) is the length obtained by adding 30 μm to the length D of the pressure chamber 10 in the X direction), as shown in FIG. When there is a positional deviation in the X direction between the channel unit 21 and the piezoelectric actuator 22 as shown (amount of positional deviation = 20 µm), the amount of deformation of the actuator section 60 due to contraction of the second active portion 62 is It can be seen that it increases compared to the case without it.

In FIG. 10(c), the solid line indicates the analysis results for the example of the present invention (distances d2, d3=20 μm), and the dashed line indicates the analysis results for the comparative example of the present invention (distances d2, d3=0 μm). . From FIG. 10(c), a positional deviation in the X direction occurs between the channel unit 21 and the piezoelectric actuator 22 as shown in FIG. Although the amount of deformation of the actuator 60 is reduced, it can be seen that the reduction in the amount of deformation of the actuator section 60 is suppressed in the example more than in the comparative example.

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

<Modification>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes are possible within the scope of the claims.

For example, the configuration of the piezoelectric layers and electrodes in the piezoelectric actuator can be changed as follows. Along with the change in electrode arrangement, the thickness (length in the Z direction) of the first active portion 61 and the second active portions 62 and 63 and the positional relationship of the first active portion 61 and the second active portions 62 and 63 in the Z direction can also be changed.

In the first modification shown in FIG. 11A, the Z-direction positions of the high-potential electrode 52 and the low-potential electrode 53 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 order from the top in the Z direction. The low potential electrode 53 is arranged between the piezoelectric layers 41 and 42 in the Z direction. The high potential electrode 52 is arranged between the piezoelectric layers 42 and 43 in the Z direction. The low potential electrode 53 is further away from the pressure chamber 10 in the Z direction than the high potential electrode 52 is.

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

In the third modification of FIG. 11(c), the number of piezoelectric layers is two. The piezoelectric body 40 has two piezoelectric layers 41 and 42 laminated in the Z direction. The high-potential electrode 52 and the low-potential electrode 53 are arranged 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. 12(a), the high potential electrode 52 extends to a position adjacent to the low potential electrode 53 in the X direction. Therefore, the first active portion 61 is not separated from the second active portions 62 and 63 in the X direction and is adjacent to the second active portions 62 and 63 .

In the fifth modification shown in FIG. 12B, similarly to the fourth modification, the high potential electrode 52 extends to a position adjacent to the low potential electrode 53 in the X direction. Therefore, the first active portion 61 is not separated from the second active portions 62 and 63 in the X direction and is adjacent to the second active portions 62 and 63 . In the fifth modification, the low potential electrode 53 is further formed over 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 modification shown in FIG. 12C, drive electrodes 51 are formed not only on the top surface of the piezoelectric layer 41 but also on the top surface of the piezoelectric layer 43 . The high-potential electrode 52 and the low-potential electrode 53 are arranged between the piezoelectric layer 41 and the piezoelectric layer 42 (that is, the same layer) in the Z direction. As a result, in each of the piezoelectric layers 41 and 42, the first active portion 61 sandwiched between the drive electrode 51 and the high potential electrode 52 in the Z direction, and the first active portion 61 sandwiched between the drive electrode 51 and the low potential electrode 53 in the Z direction. Second active portions 62 and 63 are formed.

Separation layer 44 may be omitted.

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

The second portion may not overlap the pressure chambers in the third direction and the third portion may overlap the pressure chambers in the third direction when there is no positional displacement between the channel unit and the piezoelectric actuator. Even in this case, if a positional shift occurs in the first direction and the separation distance of the second portion from the pressure chamber in the first direction becomes short, or if the second portion overlaps the pressure chamber in the third direction, The amount of deformation of the actuator section due to the contraction of the second portion is increased, and a decrease in the amount of deformation of the actuator section can be suppressed.

In the second embodiment, the separation distance between the second portion and the third portion in the first direction is locally Although varying, the separation may vary gradually in the second direction.

The pressure chamber may have a length in the first direction that is longer than a length in the second direction.

Although the number of outlets and pressure chambers is 32 in the above embodiment, it is not limited to this. For example, more than 32 outlets or pressure chambers may be provided.

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

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 deposits components in ink).

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

The present invention is not limited to printers, but can also be applied to facsimiles, copiers, multi-function machines, and the like. The present invention can also be applied to a liquid ejection apparatus used for purposes other than image recording (for example, a liquid ejection apparatus that ejects a conductive liquid onto a substrate to form a conductive pattern).

1 printer 3 head (liquid ejection head)
10 Pressure Chamber 10a One End 10b Other End 15x Discharge Port 21 Channel Unit 22 Piezoelectric Actuator 22a One End 22b Other End 34x Discharge Surface 40 Piezoelectric Substrates 41 to 43 Piezoelectric Layer 51 Drive Electrode (First Electrode, Fourth Electrode)
52 high potential electrode (second electrode, fifth electrode)
53; 253 low potential electrode (third electrode, sixth electrode)
60 actuator part 61 first active part (first part, fourth part)
61c center 62 second active part (second part, fifth part)
62a one end 62b other end 63 second active portion (third portion, sixth portion)

Claims (8)

A flow having a discharge surface parallel to a first direction and a second direction orthogonal to the first direction and defining a discharge port, and having a pressure chamber communicating with the discharge port. a 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 laminated in the third direction;
a first electrode;
a second electrode spaced apart 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 and 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 separated 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 a 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 is longer than the length of the pressure chamber in the first direction,
Another pressure chamber separated from the pressure chamber in the first direction is formed in the channel unit,
The piezoelectric actuator is
a fourth electrode spaced apart from the first electrode in the first direction;
a fifth electrode spaced apart 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 another 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 separated 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 a 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;
A liquid ejection head , wherein the third portion and the fifth portion are arranged 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, the separation distance between the third portion and the fifth portion in the first direction is 60 μm or more. 2. The liquid ejection head according to claim 1 , characterized by: A flow having a discharge surface parallel to a first direction and a second direction orthogonal to the first direction and defining a discharge port, and having a pressure chamber communicating with the discharge port. a 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 laminated in the third direction;
a first electrode;
a second electrode spaced apart 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 and 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 separated 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 a 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 is longer than the length of the pressure chamber in the first direction,
the separation distance in the cross section;
Another 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, at a position different from the cross-section in the second direction. and the separation distances are different from each other in another section passing through the liquid ejection head. Claims 1 to 3 , characterized in that, in the cross section, a separation distance between the second portion and the third portion in the first direction is longer than the length of the pressure chamber in the first direction by 30 μm or more. The liquid ejection head according to any one of . the first electrode is further separated from the pressure chamber in the third direction than the second electrode and the third electrode;
5. The liquid ejection head according to claim 1, wherein the second electrode is further separated from the pressure chamber in the third direction than the third electrode. 6. The liquid ejection head according to claim 1, wherein the length of said pressure chamber in said first direction is 340 μm or less. 2. AL (Acoustic Length: 1/2 of an acoustic resonance period in the pressure chamber of pressure waves generated in the pressure chamber due to deformation of the piezoelectric actuator) is 4.5 μs or less. 7. The liquid ejection head according to any one of items 1 to 6. A flow having a discharge surface parallel to a first direction and a second direction orthogonal to the first direction and defining a discharge port, and having a pressure chamber communicating with the discharge port. a 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 laminated in the third direction;
a first electrode;
a second electrode spaced apart 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 and 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 separated 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 positioned 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 positioned 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 positioned between the one end of the piezoelectric actuator and the center of the first portion in the first direction in the first direction. The distance in the first direction from the other ends of the two parts to the center of the first part is less than half the distance in the first direction from the one end of the pressure chamber to the other end of the pressure chamber. long,
Another pressure chamber separated from the pressure chamber in the first direction is formed in the channel unit,
The piezoelectric actuator is
a fourth electrode spaced apart from the first electrode in the first direction;
a fifth electrode spaced apart 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 another 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 separated 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;
the other pressure chamber has one end in the first direction and the other end in the first direction;
the other end of the another pressure chamber is positioned between the one end of the another pressure chamber and the other end of the piezoelectric actuator in the first direction;
The fifth portion has one end in the first direction and the other end in the first direction,
the other end of the fifth portion is positioned between the one end of the fifth portion and the other end of the piezoelectric actuator in the first direction;
the other end of the fifth portion and the one end of the another pressure chamber are positioned between the one end of the piezoelectric actuator and the center of the fourth portion in the first direction in the first direction; The distance in the first direction from the other end of the fifth portion to the center of the fourth portion is the first direction from the one end of the another pressure chamber to the other end of the another pressure chamber. longer than half the distance of
A liquid ejection head , wherein the third portion and the fifth portion are arranged between the first portion and the fourth portion in the first direction .

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