JP2016101673A - Liquid discharge head, liquid discharge unit, device for discharging liquid, and diaphragm member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem, wherein, when a salient formed on a diaphragm and an electric mechanical conversion element are jointed, the diaphragm is curved to increase the thickness of an adhesive of a central part thereby to lower a displacement transmission efficiency for the diaphragm.SOLUTION: In a diaphragm member 3, a vibration area 30 or a diaphragm for forming the wall surface of a portion of an individual liquid chamber 6 is formed with a salient 31 or an island-shaped thick part to be jointed to a piezoelectric element 12A by an adhesive. The salient 31 includes three salient portions 31a, 31b and 31c to become joint faces 33a, 33b and 33c individually to the piezoelectric element 12A. Between the adjoining salient parts 31a and 31b and between the salient parts 31b and 31c, individually, there are formed grooves 34 and 34. The three salient portions 31a, 31b and 31c are arranged, and the height of the salient 31b of the central portion is higher than the remaining salient parts 31a and 31c.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a liquid discharge head, a liquid discharge unit, an apparatus for discharging liquid, and a diaphragm member.

  As a liquid discharge head, a vibration plate made of a thin wall portion serving as a wall surface of a part of an individual liquid chamber through which a nozzle for discharging droplets communicates, and an electromechanical conversion element joined to an island-shaped convex portion provided on the vibration plate There is something with.

  2. Description of the Related Art Conventionally, there has been known a technique in which a concave portion is formed on an adhesive surface of a diaphragm with a piezoelectric element, and excess adhesive is allowed to escape in the concave portion (Patent Document 1).

  Also known is an island-shaped convex portion of the diaphragm that is formed in a cross-sectional shape whose width becomes narrower toward the piezoelectric element side and is fitted into a concave portion provided on the piezoelectric element side (Patent Document 2). ).

JP 2006-076128 A JP 2000-334949 A

  By the way, when the electromechanical conversion element is adhesively bonded to the island-shaped convex portion of the diaphragm, the thin-walled portion provided with the island-shaped convex portion is curved, and as a result, the joint surface of the island-shaped convex portion with the electromechanical conversion element Is curved. Therefore, the thickness of the adhesive at the central portion on the joint surface with the electromechanical conversion element of the island-shaped convex portion is relatively thick compared to other portions.

  As described above, when the thickness of the adhesive at the central portion of the joint surface with the electromechanical conversion element of the island-shaped convex portion is increased, the displacement transmission at the central portion of the joint surface where the displacement amount of the electromechanical conversion element is the largest is the adhesive. There is a problem that the transmission efficiency is reduced.

  The present invention has been made in view of the above problems, and an object thereof is to improve the displacement transmission efficiency with respect to the diaphragm.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A diaphragm that forms a thin wall portion that is a part of a wall surface of an individual liquid chamber through which a nozzle that discharges liquid communicates;
An electromechanical transducer element joined to a convex portion provided on the thin portion of the diaphragm,
The convex part has at least three convex part parts, the three convex part parts are arranged side by side, and a groove is formed between the adjacent convex part parts,
The height from the surface of the thin portion to the joint surface of the at least three convex portions with the electromechanical conversion element is higher in the convex portion of the central portion than the other convex portions,
In the state where the electromechanical conversion element is joined to the convex portion, the thin-walled portion has the portion corresponding to the convex portion portion in the central portion with respect to the portion corresponding to the other convex portion portion. The configuration is convex on the chamber side.

  According to the present invention, the displacement transmission efficiency with respect to the diaphragm can be improved.

FIG. 3 is an external perspective view illustrating an example of a liquid discharge head according to the present invention. FIG. 2 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction along the line AA in FIG. 1. It is a cross-sectional explanatory drawing of the nozzle arrangement direction (liquid chamber short direction) along the BB line of FIG. FIG. 5 is an explanatory cross-sectional view along the nozzle arrangement direction in a state before a piezoelectric element is bonded to the diaphragm member according to the first embodiment of the present invention. It is a plane explanatory view of one vibration region portion of the diaphragm member. FIG. 6 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where a piezoelectric element is joined to the diaphragm member. Similarly, it is an enlarged explanatory view of one vibration region portion. Similarly, it is a plane explanatory view of one vibration region portion. 6 is a cross-sectional explanatory view along the nozzle arrangement direction in a state before a piezoelectric element is bonded to the diaphragm member in Comparative Example 1. FIG. It is a plane explanatory view of one vibration region portion of the diaphragm member. FIG. 6 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where a piezoelectric element is joined to the diaphragm member. Similarly, it is an enlarged explanatory view of one vibration region portion. 10 is an explanatory cross-sectional view along a nozzle arrangement direction in a state in which a piezoelectric element is bonded to a diaphragm member in Comparative Example 2. FIG. Similarly, it is an enlarged explanatory view of one vibration region portion. FIG. 10 is an enlarged explanatory view of one vibration region portion in a state before being joined to a piezoelectric element of a vibration plate member of a liquid ejection head according to a second embodiment of the present invention. Similarly, it is an enlarged explanatory view of one vibration region portion in a state where the diaphragm member is joined to the piezoelectric element. FIG. 10 is an enlarged explanatory view of one vibration region portion in a state before being bonded to a piezoelectric element of a vibration plate member of a liquid ejection head according to a third embodiment of the present invention. Similarly, it is an enlarged explanatory view of one vibration region portion in a state where the diaphragm member is joined to the piezoelectric element. It is sectional explanatory drawing in alignment with the nozzle arrangement | sequence direction of the state before joining a piezoelectric element to the diaphragm member in 4th Embodiment of this invention. It is a plane explanatory view of one vibration region portion of the same diaphragm member. FIG. 6 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where a piezoelectric element is joined to the diaphragm member. Similarly, it is an enlarged explanatory view of one vibration region portion. Similarly, it is a plane explanatory view of one vibration region portion. It is side explanatory drawing of the mechanism part of an example of the apparatus which discharges the liquid which concerns on this invention provided with the liquid discharge unit which concerns on this invention. It is a principal part top explanatory drawing of a mechanism part similarly.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A liquid discharge head according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the head, FIG. 2 is a cross-sectional explanatory view in a direction (longitudinal direction of the liquid chamber) orthogonal to the nozzle arrangement direction along the line AA in FIG. 1, and FIG. It is sectional explanatory drawing of the nozzle arrangement direction (liquid chamber short direction) in alignment with a line.

  In this liquid discharge head, a nozzle plate 1, a flow path plate 2, and a vibration plate member 3 as a wall surface member are laminated and joined. And the piezoelectric actuator 11 which displaces the diaphragm member 3 and the frame member 20 as a common flow path member are provided.

  The nozzle plate 1 has two nozzle rows in which a plurality of nozzles 4 that discharge liquid are arranged.

  The flow path plate 2 has an individual liquid chamber 6 through which the nozzle 4 communicates via the passage 5, a fluid resistance portion 7 that supplies liquid to the individual liquid chamber 6, and a liquid introduction portion 8 that communicates with the fluid resistance portion 7. doing.

  Then, the liquid is supplied from the common liquid chamber 10 of the frame member 20 to the individual liquid chamber 6 through the liquid introduction portion 8 and the fluid resistance portion 7 through the opening 9 formed in the diaphragm member 3. Note that a filter may be provided in the opening 9.

  Here, the nozzle plate 1 is formed of a nickel (Ni) metal plate and is manufactured by an electroforming method (electroforming). Not limited to this, other metal members, resin members, laminated members of resin layers and metal layers, and the like can be used. In the nozzle plate 1, nozzles 4 are formed corresponding to the individual liquid chambers 6 and bonded to the flow path plate 2 with an adhesive. Further, a liquid repellent film is provided on the liquid ejection side surface of the nozzle plate 1.

  The flow path plate 2 forms a groove portion that forms the individual liquid chamber 6, the fluid resistance portion 7, the liquid introduction portion 8 and the like by etching the single crystal silicon substrate. In addition, not only a silicon substrate but metal members, such as SUS, can also be used, for example.

  The diaphragm member 3 is a wall surface member that forms a partial wall surface of the individual liquid chamber 6. The diaphragm member 3 has a multi-layer structure including a first layer 3a that is a thin-walled portion and a second layer 3b that may be a thick-walled portion (may be three or more layers) from the individual liquid chamber 6 side. A vibration region 30 that is a deformable diaphragm is formed in a portion corresponding to the individual liquid chamber 6 in the first layer 3a.

  A piezoelectric actuator 11 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3 on the opposite side of the diaphragm member 3 from the individual liquid chamber 6. Is arranged.

  The piezoelectric actuator 11 has a plurality of laminated piezoelectric members 12 bonded with adhesive on a base member 13, and the piezoelectric member 12 is grooved by half-cut dicing to have a required number of piezoelectric members 12. Columnar piezoelectric elements 12A and 12B are formed in a comb shape at a predetermined interval.

  The piezoelectric elements 12A and 12B of the piezoelectric member 12 are the same. In the present embodiment, one piezoelectric element 12A is used as a piezoelectric element that is displaced by giving a driving waveform, and the other piezoelectric element 12B is used as a simple support without giving a driving waveform.

  The piezoelectric element 12 </ b> A is bonded to a convex portion 31 that is an island-shaped thick portion formed in the vibration region 30 of the diaphragm member 3. The piezoelectric element 12 </ b> B is bonded to the convex portion 32 that is a thick portion of the diaphragm member 3.

  This piezoelectric member 12 is formed by alternately laminating piezoelectric layers and internal electrodes, and the internal electrodes are each extended to the end face and provided with external electrodes, and are flexible for applying drive signals to the external electrodes of the drive column 12A. An FPC 15 as a wiring board is connected.

  The frame member 20 is formed of, for example, an epoxy resin or a thermoplastic resin by injection molding (the material is not limited), and a common liquid chamber 10 to which liquid is supplied from a head tank or a liquid cartridge (not shown) is formed. ing.

  In the liquid discharge head configured as described above, for example, the voltage applied to the piezoelectric element 12A is lowered from the reference potential, so that the piezoelectric element 12A contracts, and the vibration region 30 of the diaphragm member 3 is pulled outward, so that the individual liquid As the volume of the chamber 6 expands, the liquid flows into the individual liquid chamber 6.

  Thereafter, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, and the vibration region 30 of the diaphragm member 3 is deformed in the nozzle 4 direction to contract the volume of the individual liquid chamber 6. As a result, the liquid in the individual liquid chamber 6 is pressurized, and the liquid is dropletized from the nozzle 4 and ejected (jetted) as droplets.

  Then, by returning the voltage applied to the piezoelectric element 12A to the reference potential, the vibration region 30 of the diaphragm member 3 is restored to the initial position, and the individual liquid chamber 6 expands to generate a negative pressure. The liquid is filled into the individual liquid chamber 6 from the liquid chamber 10. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (pulling-pushing), and it is also possible to perform striking or pushing depending on the direction to which the driving waveform is given.

  Next, a first embodiment of the present invention will be described with reference to FIGS. 4 is a cross-sectional explanatory view along the nozzle arrangement direction before the piezoelectric element is bonded to the diaphragm member in the same embodiment, and FIG. 5 is a plan explanatory view of one vibration region portion of the diaphragm member. 6 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where a piezoelectric element is bonded to the vibration plate member, FIG. 7 is also an enlarged explanatory view of one vibration region portion, and FIG. 8 is a plan view of the same vibration region portion. FIG.

  The diaphragm member 3 is formed with a convex portion 31 that is an island-shaped thick portion joined to the piezoelectric element 12A with an adhesive in a vibration region 30 that is a diaphragm that forms a part of the wall surface of the individual liquid chamber 6. Has been.

  And the convex part 31 has the three convex part parts 31a, 31b, 31c from which the front end surface becomes joining surface 33a, 33b, 33c with the piezoelectric element 12A, respectively, and the three convex part parts 31a, 31b, 31c are Grooves 34 and 34 are formed between the convex portion 31a and the convex portion 31b, and between the convex portion 31b and the convex portion 31c, which are arranged side by side.

  In the present embodiment, as shown in FIG. 5, by forming the groove 34 along the longitudinal direction of the piezoelectric element 12A in the convex part 31, the convex part 31 is arranged in three convex directions along the short side of the piezoelectric element 12A. Part portions 31a, 31b and 31c are formed. The “longitudinal direction” is a direction orthogonal to the nozzle arrangement direction, and the “short direction” is the nozzle arrangement direction.

  In the present embodiment, the adjacent convex portion 31a and convex portion 31b, and the convex portion 31b and convex portion 31c each form a thin portion from the joint surface with the piezoelectric element 12A that is an electromechanical transducer. The first layer 3a is formed up to the surface (thin wall surface) position, and the entire convex portion is separated by the groove 34.

  In the state where the piezoelectric element 12A is bonded to the convex portion 31, as shown in FIG. 7A, the vibration region 30 (thin wall portion) has portions corresponding to the convex portion 31b in the central portion on both sides. It protrudes toward the individual liquid chamber 6 with respect to the position corresponding to the protruding portion 31a and the protruding portion 31c.

  That is, the thickness of the convex portion 31b at the center is larger than the thickness of the convex portion 31a and the convex portion 31c located on both sides. In other words, when the height of the convex portion is from the surface of the first layer 3a that forms the vibration region 30 that is the thin-walled portion to the bonding surface with the piezoelectric element 12A that is the electromechanical transducer, the central convex portion The joint surface 33b of 31b is higher than the joint surfaces 33a and 33c of the other convex part 31a and convex part 31c located on both sides.

  In addition, the height of the convex part parts 31a-31c here is a height in the state before joining with the piezoelectric element 12A.

  Moreover, in this embodiment, the height of the convex part 31b of the center part is about 1-2 micrometers higher than the height of the other convex parts 31a and 31c.

  As described above, the difference between the height of the convex portion 31b and the height of the convex portions 31a and 31c is a state in which the vibration region 30 which is a thin portion is curved and deformed when bonded to the piezoelectric element 12A with the adhesive 300. Therefore, the height of the convex portion 31b at the center and the heights of the other convex portions 31a and 31c are substantially equal.

  In this case, in the state where the piezoelectric element 12A is joined to the convex portion 31a, the convex portion 31b, and the convex portion 31c, as shown in FIG. 7B, the joint surface 33b of the central convex portion 31b is formed. The height position h2 is the convex portion 31a located on both sides, the joint surface 33a of the convex portion 31c, the lowest point position h1 of the joint surface 33c, the convex portion 31a located on both sides, the joint surface 33a of the convex portion 31c, It is preferable to be located between the uppermost point position h3 of 33c.

  Thereby, it can reduce more reliably that the adhesive agent which moves to the joint surface 33b side from the joint surfaces 33a and 33c flows into the joint surface 33b.

  Next, in order to clarify the effect of this embodiment, a comparative example will be described first.

  First, Comparative Example 1 will be described with reference to FIGS. FIG. 9 is a cross-sectional explanatory view along the nozzle arrangement direction before the piezoelectric element is bonded to the diaphragm member in Comparative Example 1, and FIG. 10 is a plan explanatory view of one vibration region portion of the diaphragm member. FIG. 11 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where a piezoelectric element is bonded to the vibration plate member, and FIG. 12 is an enlarged explanatory view of one vibration region portion. In addition, the same code | symbol is attached | subjected to the part corresponding to this embodiment.

  The diaphragm member 3 of the comparative example 1 has an island-shaped convex portion 31 having a fixed height in a bonding surface 33 to be bonded to the piezoelectric element 12A in a vibration region 30 that is a diaphragm.

  Here, when the diaphragm member 3 and the piezoelectric member 12 are bonded with the adhesive 300, the adhesive 300 is cured while pressing the piezoelectric member 12 against the diaphragm member 3 side. At this time, since the individual liquid chamber 6 side becomes a space in the vibration region 30 and is not supported, the island-shaped convex portion 31 is pushed from the piezoelectric element 12A side, so that the vibration region 30 is formed as shown in FIG. It bends and deforms into a shape that is convex toward the individual liquid chamber 6 side.

  Therefore, the joint surface 33 of the convex portion 31 with the piezoelectric element 12 </ b> A is also curved and deformed into a shape that is convex toward the individual liquid chamber 6, similarly to the vibration region 30. Therefore, the central portion of the bonding surface 33 is moved away from the piezoelectric element 12A, and as shown in FIG. 12, the thickness of the layer of the adhesive 300 between the convex portion 31 and the piezoelectric element 12A is the central portion in the nozzle arrangement direction. The thickness tb is thicker than both end side thicknesses ta and tc.

  As described above, when the thickness of the adhesive 300 at the center portion of the joint surface 33 with the piezoelectric element 12A is increased, the displacement transmission at the center portion of the joint surface 33 with the largest displacement amount of the piezoelectric element 12A is transmitted by the adhesive 300. Absorbed and the transmission efficiency of the displacement of the piezoelectric element 12A is lowered.

  Next, Comparative Example 2 will be described with reference to FIGS. 13 and 14. 13 is a cross-sectional explanatory view along the nozzle arrangement direction in a state in which a piezoelectric element is bonded to the vibration plate member in Comparative Example 2, and FIG. 14 is an enlarged explanatory view of one vibration region portion. In addition, the same code | symbol is attached | subjected to the part corresponding to this embodiment.

  The diaphragm member 3 of the comparative example 2 has three convex portions 31a to 31c in which a joining surface 33 that joins the piezoelectric element 12A has a certain height in a vibration region 30 that is a diaphragm. That is, in the configuration of Comparative Example 2, the height of the convex portion 31b at the center is the same as the height of the other convex portions 31a and 31c, and the joint surfaces 33a, 33b, and 33c are the same height. However, this is different from the configuration of the present embodiment.

  Even with this configuration, when the vibration region 30 is curved and deformed into a shape that protrudes toward the individual liquid chamber 6 when the vibration plate member 3 and the piezoelectric member 12 are joined together with the adhesive 300, as shown in FIG. In addition, the joint surface 33b of the central convex portion 31b moves away from the piezoelectric element 12A.

  That is, in the state of FIG. 14, the joint surfaces 33 a and 33 c of the convex portion 31 a and the convex portion 31 c located on both sides are inclined such that the convex portion 31 b side of the central portion is on the lower side in the inclination direction. The joint surface 33b of the central convex portion 31b is positioned lower than the convex portions 31a and the joint surfaces 33a and 33c of the convex portion 31c located on both sides. Thereby, the adhesive 300 adhering to the joint surfaces 33a and 33c of the convex portion 31a and the convex portion 31c located on both sides is easily moved onto the joint surface 33b of the central convex portion 31b.

  Accordingly, as in Comparative Example 1 described above, the thickness of the adhesive 300 layer between the joint surface 33b of the central convex portion 31b and the piezoelectric element 12A is equal to the joint surface 33a of the convex portions 31a and 31c on both sides. , 33c becomes thicker than the thicknesses ta and tc.

  Therefore, even in the configuration of Comparative Example 2, the displacement transmission at the center of the joint surface 33 where the displacement amount of the piezoelectric element 12A is the largest is absorbed by the adhesive 300, and the displacement transmission efficiency of the piezoelectric element 12A is lowered.

  On the other hand, in the diaphragm member 3 in the present embodiment, the height of the convex portion 31b at the center is higher than the height of the other convex portions 31a and 31c in a state before being bonded to the piezoelectric element 12A. doing. That is, the joint surface 33b in the central part is higher than the heights of the joint surfaces 33a and 33c in other parts.

  Therefore, as shown in FIG. 6, when the convex portion 31 of the vibration plate member 3 and the piezoelectric element 12A are joined, when the vibration region 30 is curved and deformed to be convex toward the individual liquid chamber 6 side, The distance between the bonding surface 33b and the piezoelectric element 12A is substantially the same as the distance between the bonding surfaces 33a and 33c and the piezoelectric element 12A in other parts.

  That is, as described above, it is possible to reduce the adhesive that moves from the bonding surfaces 33a and 33c to the bonding surface 33b from flowing onto the bonding surface 33b.

  Thereby, the center part of the convex part 31 and the center part with the largest displacement amount of the piezoelectric element 12A can be joined in a state where the thickness of the layer of the adhesive 300 is not increased, and the displacement of the piezoelectric element 12A is efficiently performed. It is transmitted to the vibration area 30.

  Moreover, since the groove | channel 34 formed in the convex part 31 functions also as an adhesive agent escape which escapes an excess adhesive agent, the protrusion of the adhesive agent 300 can be reduced.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 15 and 16. FIG. 15 is an enlarged explanatory view of one vibration region portion before being joined to the piezoelectric element of the diaphragm member of the liquid ejection head according to the embodiment, and FIG. 16 is also a state in which the diaphragm member is joined to the piezoelectric element. It is expansion explanatory drawing of one vibration area | region part.

  In the present embodiment, in the first embodiment, the central convex portion constituting the convex portion 31 is further divided in the nozzle arrangement direction to form two convex portions 31b1 and 31b2, and the convex portion The portion 31 is constituted by four convex portions as a whole.

  By configuring in this way, the same effects as the first embodiment can be obtained, and the convex portion 31b (31b1, 31b2) in the central portion can be more accurately matched to the curved shape of the vibration region 30. Can be followed.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 17 is an enlarged explanatory view of one vibration region portion before joining with the piezoelectric element of the diaphragm member of the liquid ejection head according to the embodiment, and FIG. 18 is a state in which the diaphragm member is joined with the piezoelectric element. It is expansion explanatory drawing of one vibration area | region part.

  In the present embodiment, the groove 34 formed from the joint surface 33 side of the convex portion 31 is formed in a state that does not reach the thickness portion of the vibration region 30.

  Thereby, as for the convex part 31, the part by the side of a front-end | tip part (joining surface side) is divided into three convex part parts 31a-31c, and the vibration area | region 30 side which is a thin part side is formed by the integral common part 31d. .

  Even in this configuration, since the thickness of the convex portion 31 itself is thin, as shown in FIG. 18, when the convex portion 31 of the diaphragm member 3 and the piezoelectric element 12A are joined, the bending deformation of the vibration region 30 is performed. Accordingly, the common portion 31d of the convex portion 31 is also curved and deformed in the same shape.

  Therefore, as in the above embodiments, the distance between the central joint surface 33b and the piezoelectric element 12A is substantially the same as the distance between the other joint surfaces 33a and 33c and the piezoelectric element 12A, and the displacement of the piezoelectric element 12A is efficient. Is transmitted to the vibration region 30.

  In each of the above embodiments, the diaphragm member is formed by an etching method, but it can also be formed by a method other than etching, such as a Ni electroforming method.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 19 is a cross-sectional explanatory view along the nozzle arrangement direction before the piezoelectric element is bonded to the diaphragm member in the same embodiment, and FIG. 20 is a plan explanatory view of one vibration region portion of the diaphragm member. 21 is a cross-sectional explanatory view along the nozzle arrangement direction in a state where the piezoelectric element is bonded to the vibration plate member, FIG. 22 is an enlarged explanatory view of one vibration region portion, and FIG. 23 is a plan view of the same vibration region portion. FIG.

  The diaphragm member 3 of the present embodiment is formed by forming a first layer 3a, a second layer 3b, a third layer 3c, and a fourth layer 3d by a Ni electroforming method.

  And the 1st layer 3a forms the vibration area | region 30 which is a thin part. The 2nd layer 3b and the 3rd layer 3c form the convex parts 31 and 32 used as a thick part. The 4th layer 3d is formed on the 3rd layer 3c which forms the convex part 31b of the center part. The second layers 3b and 3c have an overhang shape.

  Here, the convex part 31 is integrally formed by the second layer 3b on the vibration region 30 side (thin wall part side), and the separated convex part parts 31a, 31b, A third layer 3c to be 31c is formed. And the 4th layer 3d is formed in the convex part 31b formed of the 3rd layer 3c.

  Thereby, the convex part 3b of the center part formed with the 3rd layer 3c and the 4th layer 3d becomes higher than the convex parts 31a and 31c formed with the other 3rd layer 3c.

  Therefore, the joint surface 33 of the convex portion 31 has a central joint surface 33b higher than the joint surfaces 33a and 33c of other portions.

  Since it is configured in this manner, as shown in FIG. 22, when the convex portion 31 and the piezoelectric element 12A are joined, when the vibration region 30 is curved and deformed into a shape that protrudes toward the individual liquid chamber 6, The distance between the central joint surface 33b and the piezoelectric element 12A is substantially the same as the distance between the other joint surfaces 33a and 33c and the piezoelectric element 12A.

  As a result, as in each of the above embodiments, the bonding can be performed without increasing the thickness of the layer of the adhesive 300 between the piezoelectric element 12A and the bonding surface 33b at the center of the convex portion 31, and the piezoelectric element 12A can be bonded. The displacement can be efficiently transmitted to the vibration region 30.

  In the above embodiment, the groove 34 is formed in the convex portion 31 of the vibration region 30 along the nozzle arrangement direction, and the three convex portion portions 31a and 31b are arranged in the direction orthogonal to the nozzle arrangement direction. , 31c. Moreover, the number of the convex part which comprises a convex part is not limited to 3 or 4 mentioned above, It can also be 5 or more.

  Moreover, in the above embodiment, the convex part 32 can be similarly formed with a groove and divided into a plurality of convex parts, and the groove can be used as an adhesive relief. However, it is preferable that the height of each convex portion in this case be the same.

  Next, an example of an apparatus for ejecting a liquid according to the present invention that includes the liquid ejection unit according to the present invention will be described with reference to FIGS. FIG. 24 is an explanatory side view of the mechanism portion of the apparatus, and FIG. 25 is an explanatory plan view of an essential part of the mechanism portion.

  The apparatus for discharging the liquid is a serial type image forming apparatus. A carriage 433 is held so as to be reciprocally movable in the main scanning direction (arrow direction) by main and sub guide rods 431 and 432 which are guide members horizontally mounted on the left and right side plates 421A and 421B.

  In the carriage 433, two liquid discharge units 430 (430A, 430A, 430A, 430A, 430A) according to the present invention are integrated with a liquid discharge head 434 according to the present invention and a head tank (also referred to as a sub tank) 435 that supplies liquid to the liquid discharge head 434. 430B). The liquid discharge head 434 is mounted with a nozzle row composed of a plurality of nozzles in the sub-scanning direction orthogonal to the main scanning direction and the liquid discharging direction facing downward.

  Here, the liquid discharge head 434 has two nozzle rows. Then, one nozzle row of the liquid discharge head 434 of one liquid discharge unit 430A discharges black (K) liquid, and the other nozzle row discharges cyan (C) liquid.

  In addition, one nozzle row of the liquid discharge head 434 of the other liquid discharge unit 430B discharges magenta (M) liquid, and the other nozzle row discharges yellow (Y) liquid.

  Note that, here, two liquid discharge heads are used to discharge four colors of liquid, but four nozzle rows are arranged in one liquid discharge head, and four liquids are discharged from one liquid discharge head. Each color can also be ejected.

  In addition, “integration” in the liquid discharge units 430A and 430B means that the liquid discharge head 434 and the head tank 435 are fixed directly or via a filter member or the like by a fastening member or an adhesive, or It means that they are connected to each other by tubes.

  A main tank 410 (410k, 410c, 201m, 210y), which is a liquid cartridge of each color, is detachably attached to the cartridge holder 404 on the apparatus main body side. Then, the liquids of the respective colors are fed from the main tanks 410 of the respective colors to the head tanks 435 of the respective liquid discharge units 430A and 430B through the supply tubes 436 of the respective colors by the liquid feeding unit 424 including a liquid feeding pump.

  On the other hand, as a paper feeding unit for feeding the paper 442 stacked on the paper stacking unit (pressure plate) 441 of the paper feed tray 402, a half-moon roller (feeding) that separates and feeds the paper 442 from the paper stacking unit 441 one by one. Paper separation roller 443 and a separation pad 444 facing the paper feeding roller 443.

  Further, a guide 445 for conveying and guiding the fed paper 442, a counter roller 446, a conveyance guide member 447, and a pressing member 448 having a tip pressure roller 449 are provided. Further, a transport belt 451 is provided as a transport unit that sucks the transported paper 442 and transports the transported paper 442 at a position facing the liquid discharge head 434 of the liquid discharge unit 430.

  Here, the conveyance belt 451 is an endless belt, and is configured to be wound around the conveyance roller 452 and the tension roller 453 so as to circulate in the belt conveyance direction (sub-scanning direction). Here, an electrostatic conveyance belt charged by a charging roller 456 that is a charging unit is used as the conveyance belt 451. However, the conveyance belt 251 may be a conveyance belt that is attracted by air suction. Moreover, as a conveyance means, you may convey by two rollers, without using a conveyance belt.

  A separation claw 461 for separating the paper 242 from the transport belt 451, a paper discharge roller 462, and a paper discharge roller 463 are provided on the downstream side of the tension roller 453 around which the transport belt 451 is wound. A paper discharge tray 403 is provided below.

  A double-sided unit 471 is detachably attached to the back surface of the apparatus main body. The duplex unit 471 takes in and reverses the sheet 442 returned by the reverse rotation of the transport belt 451 and feeds it again between the counter roller 446 and the transport belt 451. The upper surface of the duplex unit 471 is a manual feed tray 472.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the state of the nozzles of the liquid discharge heads 434 of the liquid discharge units 430A and 430B is disposed in the non-print region on one side in the scanning direction of the carriage 433.

  The maintenance / recovery mechanism 481 includes caps 482a and 482b for capping the nozzle surface of the liquid discharge head 434. The maintenance / recovery mechanism 481 includes a blade member 483 for wiping the nozzle surface. In addition, the maintenance / recovery mechanism 481 includes an empty discharge receptacle 484 for receiving a liquid when performing an empty discharge for discharging a liquid that does not contribute to image formation in order to discharge the thickened liquid.

  In the non-printing area on the other side in the scanning direction of the carriage 433, an empty discharge receiver 488 that receives liquid when empty discharge is performed during image formation or the like is disposed. The idle discharge receptacle 488 includes an opening 489 along the nozzle row direction of the liquid discharge head 434.

  In this image forming apparatus, the paper 442 is separated and fed one by one from the paper feed tray 402, and the paper 442 fed substantially vertically upward is guided by the guide 445, and between the transport belt 451 and the counter roller 446. It is sandwiched and conveyed. Further, the leading edge of the sheet 442 is guided by the conveying guide 437 and pressed against the conveying belt 451 by the leading end pressing roller 449, and the conveying direction is changed by approximately 90 °.

  When the paper 442 is fed onto the charged transport belt 451, the paper 442 is attracted to the transport belt 451, and the paper 442 is transported in the sub-scanning direction by the circular movement of the transport belt 451.

  Therefore, by driving the liquid discharge heads 434 of the liquid discharge units 430A and 430B according to the image signal while moving the carriage 433, liquid is discharged onto the stopped paper 442 to record an image for one line. . Then, after the sheet 442 is conveyed by a predetermined amount, image formation of the next row is performed. Upon receiving a recording end signal or a signal that the trailing edge of the paper 442 has reached the recording area, the recording operation is finished and the paper 442 is discharged onto the paper discharge tray 403.

  As described above, since the image forming apparatus includes the liquid discharge head or the liquid discharge head unit according to the present invention, a high-quality image can be stably formed.

  In the present application, the “apparatus for ejecting liquid” is an apparatus capable of ejecting a liquid to an object to which the liquid can adhere.

  This "device for ejecting liquid" includes not only a portion for ejecting liquid, but also means for feeding, transporting, and discharging paper to which liquid adheres, and other devices referred to as pre-processing devices and post-processing devices Etc. can be included.

  In addition, the “device for ejecting liquid” includes devices called conventional recording devices, printing devices, image forming devices, droplet ejecting devices, liquid ejecting devices, processing liquid coating devices, three-dimensional modeling devices themselves. It is.

  Further, the “apparatus for ejecting liquid” is not limited to the one in which a significant image such as a character or a figure is visualized by the liquid adhering to the liquid adherable one. For example, what forms a pattern etc. which does not have a meaning itself, and what forms a three-dimensional image are also included.

  In addition, the above-mentioned “thing to which the liquid adheres” means that the liquid can adhere even temporarily. In place of the term “the liquid adheres to”, when using alternative terms such as paper, medium, recording medium, recording medium, recording paper, recording paper, powder layer (powder layer), etc. The term is intended to include those to which all liquids adhere unless specifically limited.

  In addition, the material of “the material to which the liquid adheres” is not limited as long as the liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics can be adhered even temporarily.

  In addition, “liquid” includes ink, processing liquid, DNA sample, resist, pattern material, binder, and the like.

  Further, the “device for ejecting liquid” includes both a serial type device that moves the liquid ejection head and a line type device that does not move the liquid ejection head, unless otherwise specified.

  In addition, the “liquid discharge unit” means a unit in which liquid discharge portions are integrated. For example, the “liquid discharge unit” includes a head tank, a carriage, a supply mechanism, a maintenance mechanism, and a main scanning movement mechanism arbitrarily combined with a liquid discharge head.

  For example, the “liquid discharge unit” includes the liquid discharge head and the head tank described in the above embodiment integrated, the liquid discharge head and the carriage integrated, and the liquid discharge head, the head tank, and the carriage integrated. Things are included.

  In addition, a liquid filter unit in which a filter unit (a filter member and a distribution channel described above are added) is added to these liquid discharge units.

  Also included are those in which the liquid ejection head and the maintenance mechanism are integrated, those in which the liquid ejection head, the maintenance mechanism, and the main scanning movement mechanism are integrated, and those in which the liquid ejection head, the main scanning movement mechanism, and the supply mechanism are integrated. It is.

  The main scanning movement mechanism is configured by combining a carriage, a guide member for guiding the carriage, or a driving source and a carriage movement mechanism. The supply mechanism includes a loading unit on which a main tank is mounted, a tube, a head tank, and the like. The maintenance mechanism is a combination of at least two of a cap, a wiper member, a suction means such as a suction pump leading to the cap, and an idle discharge receiver.

  Furthermore, the “liquid discharge unit” includes a unit constituted by a part excluding a mechanism for transporting a liquid adhering unit from the mechanism unit described in the embodiment.

  “Integrated” means a state in which two or more members related to liquid ejection are connected to each other as a representative example, and means that two or more members related to liquid ejection constitute one unit. .

  The “liquid discharge head” is not limited to the pressure generating means to be used. For example, in addition to the piezoelectric actuator described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, an electrostatic actuator including a diaphragm and a counter electrode, or the like may be used.

  In addition, the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Flow path plate 3 Vibrating plate member 4 Nozzle 6 Individual liquid chamber 10 Common liquid chamber 11 Piezoelectric actuator 12 Piezoelectric member 20 Frame member 30 Vibrating region 31 Convex part 33 Joint surface 34 Groove 430 Liquid discharge unit 434 Liquid discharge head 435 Head tank 300 Adhesive

Claims (9)

A diaphragm that forms a thin wall portion that is a part of a wall surface of an individual liquid chamber through which a nozzle that discharges liquid communicates;
An electromechanical transducer element joined to a convex portion provided on the thin portion of the diaphragm,
The convex part has at least three convex part parts, the three convex part parts are arranged side by side, and a groove is formed between the adjacent convex part parts,
The height from the surface of the thin portion to the joint surface of the at least three convex portions with the electromechanical conversion element is higher in the convex portion of the central portion than the other convex portions,
In the state where the electromechanical conversion element is joined to the convex portion, the thin-walled portion has the portion corresponding to the convex portion portion in the central portion with respect to the portion corresponding to the other convex portion portion. A liquid discharge head that is convex toward the chamber. The liquid ejection according to claim 1, wherein the groove of the convex portion is formed along a longitudinal direction of the electromechanical conversion element, and the at least three convex portion portions are arranged in a short direction. head. The groove of the convex portion is formed along a short direction of the electromechanical conversion element, and the at least three convex portions are formed side by side in the longitudinal direction. The liquid discharge head described in 1. The adjacent convex part is separated by the groove formed from the joint surface with the electromechanical transducer to the thin part surface position. Liquid discharge head. The adjacent convex portions are partially separated on the joint surface side by the groove formed from the joint surface with the electromechanical conversion element to a position not reaching the thin wall surface position. The liquid discharge head according to claim 1. The convex portion has at least a two-layer structure,
2. The liquid discharge head according to claim 1, wherein the layer on the thin-walled portion side is integrated, and the at least three convex portions are formed by a layer forming the bonding surface.   A liquid discharge unit comprising the liquid discharge head according to claim 1.   An apparatus for ejecting liquid, comprising the liquid ejection head according to claim 1 or the liquid ejection unit according to claim 7. Form a thin wall that will be part of the wall of the individual liquid chamber that leads to the nozzle that discharges the liquid,
A diaphragm member in which an electromechanical conversion element is joined to a convex portion provided in the thin portion,
The convex part has at least three convex part parts, the three convex part parts are arranged side by side, and a groove is formed between the adjacent convex part parts,
The height from the surface of the thin wall portion to the joint surface of the at least three convex portions with the electromechanical conversion element is such that the convex portion at the center is higher than the other convex portions. Diaphragm member.

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