Liquid ejecting head, liquid ejecting apparatus, and piezoelectric device
10562302 ยท 2020-02-18
Assignee
Inventors
Cpc classification
B41J2/14233
PERFORMING OPERATIONS; TRANSPORTING
B41J2/14201
PERFORMING OPERATIONS; TRANSPORTING
B41J2002/14306
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A liquid ejecting head includes a flow path substrate in which a nozzle through which liquid is ejected, a pressure chamber that communicates with the nozzle and a liquid supply chamber that communicates with the pressure chamber are formed, a vibration plate that is installed on the flow path substrate and overlaps with the pressure chamber and the liquid supply chamber, and a piezoelectric element that is formed on the vibration plate on an opposite side from the pressure chamber, in which a portion of the vibration plate overlapping with the pressure chamber is thinner in a thickness than a portion of the vibration plate overlapping with the liquid supply chamber.
Claims
1. A liquid ejecting head comprising: a nozzle through which liquid is ejected; a flow path substrate in which a pressure chamber and a liquid supply chamber are formed, the pressure chamber communicating with the nozzle, and the liquid supply chamber communicating with the pressure chamber; a housing section in which a liquid storage chamber is formed, the storage chamber storing liquid and communicating with the liquid supply chamber; a vibration plate that is installed on the flow path substrate; and a piezoelectric element that is formed on the vibration plate on an opposite side from the pressure chamber, wherein the vibration plate overlaps both the pressure chamber in the flow path substrate and the liquid storage chamber in the housing section, and wherein a portion of the vibration plate overlapping with the pressure chamber is thinner in a thickness than a portion of the vibration plate overlapping with the liquid storage chamber.
2. The liquid ejecting head according to claim 1, wherein the portion of the vibration plate overlapping with the liquid storage chamber includes a filter section in which a plurality of through-holes is formed.
3. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 2.
4. The liquid ejecting head according to claim 2, wherein a first through-hole and a second through-hole out of the plurality of through-holes are formed at different positions in both an X direction and a Y direction, the Y direction being orthogonal to the X direction.
5. The liquid ejecting head according to claim 1, wherein a recess section that is recessed in comparison with another portion is formed on a surface of the portion of the vibration plate overlapping with the pressure chamber on a side of the pressure chamber.
6. The liquid ejecting head according to claim 3, wherein a surface of the portion of the vibration plate overlapping with the liquid supply chamber on a side of the liquid supply chamber liquid storage chamber is formed of a compressive stress film, and the compressive stress film is not formed on the surface of the portion of the vibration plate overlapping with the pressure chamber on the side of the pressure chamber.
7. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 6.
8. The liquid ejecting head according to claim 3, wherein the surface of the portion of the vibration plate overlapping with the liquid supply chamber on the side of liquid storage chamber is formed of a tensile stress film, and the tensile stress film is not formed on the surface of the portion of the vibration plate overlapping with the pressure chamber on the side of the pressure chamber.
9. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 8.
10. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 5.
11. The liquid ejecting head according to claim 1, wherein a portion of the vibration plate at which the piezoelectric element is formed is thinner in a thickness over an entire area than the portion of the vibration plate overlapping with the liquid supply chamber.
12. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 11.
13. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 1.
14. The liquid ejecting head according to claim 1, wherein the filter section of the vibration plate comprises a first layer and a second layer, the first layer being closer to the flow path substrate than the second layer.
15. The liquid ejecting head according to claim 14, wherein the portion of the vibration plate overlapping with the pressure chamber consists from the second layer and does not consist from the first layer, and wherein the portion of the vibration plate overlapping with the liquid storage chamber consists from both the first layer and the second layer.
16. The liquid ejecting head according to claim 14, wherein the portion of the vibration plate overlapping with the liquid storage chamber includes a filter section in which a through-hole is formed, and wherein the through-hole passes through both the first layer and the second layer.
17. The liquid ejecting head according to claim 1, wherein the housing section stacks on the vibration plate.
18. A piezoelectric device that is provided in a liquid ejecting head that includes a flow path substrate in which a pressure chamber and a liquid supply chamber are formed, the pressure chamber communicating with a nozzle and the supply chamber communicating with the pressure chamber, the ejecting head further including a housing section in which a liquid storage chamber is formed, the storage chamber storing liquid and communicating with the liquid supply chamber, the piezoelectric device comprising: a vibration plate that is installed on the flow path substrate; and a piezoelectric element that is formed on the vibration plate on an opposite side from the pressure chamber, wherein the vibration plate overlaps both the pressure chamber in the flow path substrate and the liquid storage chamber in the housing section, and wherein a portion of the vibration plate overlapping with the pressure chamber is thinner in a thickness than a portion of the vibration plate overlapping with liquid storage chamber.
19. The liquid ejecting head according to claim 18, wherein the filter section of the vibration plate comprises a first layer and a second layer, the first layer being closer to the flow path substrate than the second layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
(2)
(3)
(4)
(5)
(6)
(7)
(8)
DESCRIPTION OF EXEMPLARY EMBODIMENTS
First Embodiment
(9)
(10) As illustrated in
(11) The moving mechanism 24 reciprocates the liquid ejecting head 26 in an X direction under the control of the control unit 20. The X direction is a direction that intersects with (typically, is orthogonal to) the Y direction in which the medium 12 is transported. The moving mechanism 24 according to the first embodiment includes a substantially box-shaped transport body 242 (carriage) for housing the liquid ejecting head 26, and a transport belt 244 to which the transport body 242 is fixed. Note that, a configuration in which a plurality of the liquid ejecting heads 26 is mounted in the transport body 242, or a configuration in which the liquid container 14 is mounted in the transport body 242 with the liquid ejecting head 26 may also be employed.
(12) The liquid ejecting head 26 ejects ink supplied from the liquid container 14 to the medium 12 through a plurality of nozzles (ejection holes) N under the control of the control unit 20. By each liquid ejecting head 26 ejecting the ink to the medium 12 in parallel with the transport of the medium 12 by the transport mechanism 22 and the repetitive reciprocation of the transport body 242, a desired image is formed on a surface of the medium 12.
(13)
(14) The nozzle plate 61, the flow path substrate 63, and the vibration plate 65 are plate-shaped members that are long in the Y direction. As illustrated in
(15) The nozzle plate 61 is a plate-shaped member in which the plurality of nozzles N arrayed in the Y direction is formed. Each of the nozzles N is a through-hole through which the ink is ejected. Note that, the nozzle plate 61 and the flow path substrate 63 are formed, for example, by processing a silicon (Si) single-crystal substrate through a semiconductor manufacturing technique such as etching or the like. Note that, any materials, any manufacturing methods, or the like may be employed for each element of the liquid ejecting head 26. The Y direction may also be rephrased as a direction in which the plurality of nozzles N is arrayed.
(16) The flow path substrate 63 is a plate-shaped member for forming a flow path of the ink. As illustrated in
(17) As illustrated in
(18) As illustrated in
(19) The filter chamber C21 is a space for supplying the ink to the pressure chamber C1, and stores the ink supplied from the liquid storage chamber CR. The ink stored in the filter chamber C21 is supplied to the pressure chamber C1 through the throttle section C22. The throttle section C22 is a space for ensuring flow path resistance, and functions as a flow path for causing the ink to flow from the filter chamber C21 to the pressure chamber C1. The filter chamber C21 and the throttle section C22 function as a liquid supply chamber C2 for supplying the ink to the pressure chamber C1. The liquid supply chamber C2 communicates with the pressure chamber C1. As is understood from the above description, the plurality of pressure chambers C1 is supplied with the ink stored in the liquid storage chamber CR through the liquid supply chambers C2, respectively, and filled with the ink, in parallel. As described above, the vibration plate 65 is installed on the flow path substrate 63, and overlaps with the pressure chamber C1 and the liquid supply chamber C2 (the throttle section C22 and the filter chamber C21). In the following description, a portion of the vibration plate 65 overlapping with the pressure chamber C1 is expressed as a vibrating portion R1, and a portion of the vibration plate 65 overlapping with the liquid supply chamber C2 is expressed as a fixing portion R2. The piezoelectric element 67 is installed in the vibrating portion R1, the filter section F is formed in the fixing portion R2 (specifically, in a portion overlapping with the filter chamber C21).
(20) As illustrated in
(21) A specific configuration of the vibration plate 65 will be described in detail below.
(22) As illustrated in
(23) The first layer 651 is, for example, formed by forming a film of silicon oxide (for example, SiO.sub.2) through chemical vapor deposition. The first layer 651 film-formed through the chemical vapor deposition of the silicon oxide is a compressive stress film with a compressive stress remaining in the inside. The second layer 652 is, for example, formed by laminating silicon (Si), polycrystalline silicon, amorphous silicon, silicon oxide, and silicon nitride (for example, Si.sub.3N.sub.4). The second layer 652 is formed using a known film formation technique. A film thickness of the first layer 651 is smaller than a film thickness of the second layer 652. By covering the surface of the second layer 652 with the first layer 651 after forming the second layer 652, and then selectively removing the first layer 651 in the vibrating portion R1 using a known processing technique such as etching or the like, the vibration plate 65 is formed. As is understood from the above description, the surface of the vibration plate 65 in the fixing portion R2 on the liquid supply chamber C2 side is formed of the compressive stress film, and the compressive stress film is not formed on the surface of the vibration plate 65 in the vibrating portion R1 on the pressure chamber C1 side.
(24)
(25)
(26) Here, in order to ensure the amplitude (displacement amount) of the vibrating portion R1, the vibration plate 65 is desirably thin in the thickness. On the other hand, in order to ensure a strength of the fixing portion R2, the vibration plate 65 is desirably thick in the thickness. Accordingly, in a configuration in which the thickness of the vibration plate 65 is constant regardless of a position in the vibration plate 65 (hereinafter, referred to as a comparative example 1), it is difficult to ensure the strength of the fixing portion R2 while ensuring the amplitude of the vibrating portion R1. In contrast, by the configuration according to the first embodiment in which the thickness T1 of the vibrating portion R1 is smaller than the thickness T2 of the fixing portion R2, it is possible to ensure the strength of the fixing portion R2 while ensuring the displacement amount of the vibrating portion R1. Additionally, since, by making the thickness T2 of the fixing portion R2 larger than that of the vibrating portion R1, the strength of the fixing portion R2 can be ensured, in comparison with a configuration in which a mechanical strength is ensured by forming an insulating layer on the second surface S2 of the fixing portion R2 in the comparative example 1, for example, the configuration of the liquid ejecting head 26 is simplified.
Second Embodiment
(27) A second embodiment of the invention will be described. Note that, in each mode described as an example below, the elements whose actions or functions are the same as those in the first embodiment are given the reference numerals used in the description in the first embodiment, and detailed descriptions thereof will be appropriately omitted.
(28) The first layer 651 according to the second embodiment is formed by forming a film of silicon nitride through chemical vapor deposition. The first layer 651 film-formed through the chemical vapor deposition of the silicon nitride is a tensile stress film with a tensile stress remaining in the inside. The second layer 652 according to the second embodiment is formed in the same manner as in the first embodiment, for example, by laminating silicon, polycrystalline silicon, amorphous silicon, silicon oxide, and silicon nitride. By covering the surface of the second layer 652 with the first layer 651 after forming the second layer 652, and then selectively removing the first layer 651 in the vibrating portion R1 using a known processing technique such as etching or the like, the vibration plate 65 is formed. As is understood from the above description, the surface of the vibration plate 65 in the fixing portion R2 on the liquid supply chamber C2 side is formed of the tensile stress film, and the tensile stress film is not formed on the surface of the vibration plate 65 in the vibrating portion R1 on the pressure chamber C1 side.
(29)
(30) Here, in a state where the piezoelectric element 67 is supplied with the driving signal (hereinafter, referred to as a driven state), since a pressure from the ink is applied to the vibrating portion R1 (force of the ink for pushing up the vibration plate 65), the vibrating portion R1 bends to the piezoelectric element 67 side. Accordingly, in a case where the vibrating portion R1 bends to the piezoelectric element 67 side in the non-driven state of the piezoelectric element 67 (hereinafter, referred to as a comparative example 2), the bend to the piezoelectric element 67 side is further increased in the driven state (that is, a degree of the deformation of the vibration plate 65 increases). Accordingly, in the vicinity of boundary between the portion that is bonded and the portion that is not bonded (typically, the vibrating portion R1) to the flow path substrate 63, of the vibration plate 65 in the comparative example 2, a crack is easy to be generated. In the second embodiment, since the vibrating portion R1 bends to the pressure chamber C1 side in the non-driven state of the piezoelectric element 67, in comparison with the comparative example 2, the crack can be suppressed from being generated in the vibration plate 65.
(31) In the second embodiment as well, in the same manner as in the first embodiment, the strength of the fixing portion R2 can be ensured while ensuring the displacement amount of the vibrating portion R1. Additionally, by making the fixing portion R2 thicker in the thickness than the vibrating portion R1, the strength of the fixing portion R2 can be ensured, the configuration of the liquid ejecting head 26 can be simplified.
(32) Variation
(33) Each mode described above may be variously modified. Specific modification aspects that may be applied to each mode described above will be described below as an example. Note that, two or more aspects arbitrarily selected from examples described below may appropriately be combined in a range in which they are not inconsistent with each other.
(34) 1. In the first embodiment, although the first layer 651 is formed by film-forming of the silicon oxide through the chemical vapor deposition, the formation method and the material of the first layer 651 are not limited to the above-described example. Further, in the second embodiment, although the first layer 651 is formed by film-forming of the silicon nitride through the chemical vapor deposition, the formation method and the material of the first layer 651 are not limited to the above-described example. It is not essential that the compressive stress or the tensile stress remains in the first layer 651.
(35) 2. In each mode described above, although the configuration in which the fixing portion R2 includes the filter section F is described as an example, whether to provide the filter section F in the fixing portion R2 is optional. Note that, according to the configuration in which the fixing portion R2 includes the filter section F, bubbles, foreign matter, or the like included in the ink can be captured. Additionally, since the vibration plate 65 also functions as the filter section F, in comparison with the configuration in which the filter section F is provided as a different element from the vibration plate 65, the configuration of the liquid ejecting head 26 is simplified.
(36) 3. In each mode described above, although the configuration in which the recess section D is formed on the surface of the vibrating portion R1 on the pressure chamber C1 side (that is, the first surface S1) is described as an example, a specific shape of the vibration plate 65 may be changed as desired as long as the vibrating portion R1 is thinner in the thickness than the fixing portion R2. For example, the recess section D that is recessed in comparison with other portions may be formed on the surface of the vibrating portion R1 on the piezoelectric element 67 side (that is, the second surface S2). In the configuration in which the vibrating portion R1 is thinner in the thickness than the fixing portion R2, an effect that the strength of the fixing portion R2 can be ensured while ensuring the displacement amount of the vibrating portion R1 is achieved. Note that, according to the configuration in which the recess section D is formed on the surface of the vibrating portion R1 on the pressure chamber C1 side, in comparison with the configuration in which the recess section D is formed on the surface of the vibrating portion R1 on the piezoelectric element 67 side, a capacity of the pressure chamber C1 can be sufficiently ensured.
(37) 4. In each mode described above, although the vibration plate 65 is configured of the first layer 651 and the second layer 652, the structure of the vibration plate 65 is not limited to the above-described example. For example, the vibration plate 65 may be formed as a single layer. For example, by film-forming any one or both of silicon oxide and silicon nitride through the chemical vapor deposition, the vibration plate 65 may be formed. Alternatively, by laminating silicon, polycrystalline silicon, amorphous silicon, silicon oxide, silicon nitride, or the like, the vibration plate 65 may be formed.
(38) 5. In the first embodiment, although the configuration in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the compressive stress film, and the compressive stress film is not formed on the surface of the vibrating portion R1 on the pressure chamber C1 side is described as an example, types of the surfaces of the vibrating portion R1 and the fixing portion R2 on the flow path substrate 63 side are not limited to the above-described configuration. For example, a configuration in which the compressive stress film is formed on the surfaces of both the vibrating portion R1 and the fixing portion R2, or a configuration in which a film other than the compressive stress film is formed on the surfaces of both the vibrating portion R1 and the fixing portion R2 may also be employed. Note that, by the configuration according to the first embodiment in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the compressive stress film, and the compressive stress film is not formed on the surface of the vibrating portion R1 on the pressure chamber C1 side, the vibrating portion R1 bends to the piezoelectric element 67 side. Accordingly, as described in the first embodiment, in comparison with the configuration in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the tensile stress film (that is, the configuration in which the vibrating portion R1 bends to the flow path substrate 63 side), the deterioration of the piezoelectric element 67 can be suppressed.
(39) 6. In the second embodiment, although the configuration in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the tensile stress film, and the tensile stress film is not formed on the surface of the vibration plate 65 in the vibrating portion R1 on the pressure chamber C1 side is described as an example, types of the surfaces of the vibrating portion R1 and the fixing portion R2 on the flow path substrate 63 side are not limited to the above-described configuration. For example, a configuration in which the tensile stress film is formed on the surfaces of both the vibrating portion R1 and the fixing portion R2, or a configuration in which a film other than the tensile stress film is formed on the surfaces of both the vibrating portion R1 and the fixing portion R2 may also be employed. Note that, by the configuration according to the second embodiment in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the tensile stress film, and the tensile stress film is not formed on the surface of the vibration plate 65 in the vibrating portion R1 on the pressure chamber C1 side, the vibrating portion R1 bends to the pressure chamber C1 side. Accordingly, as described in the second embodiment, in comparison with the configuration in which the surface of the fixing portion R2 on the liquid supply chamber C2 side is formed of the compressive stress film (that is, the configuration in which the vibrating portion bends to the piezoelectric element 67 side), the crack can be suppressed from being generated in the vibration plate 65.
(40) 7. In each mode described above, although the recess section D is formed by removing the first layer 651 at the vibrating portion R1, the formation method of the recess section D is not limited to the above-described example. For example, the recess section D may be formed by partially removing the first layer 651 in the vibrating portion R1 in the thickness direction. Additionally, the recess section D may be formed by removing the first layer 651 and a part of the second layer 652 in the thickness direction. In other words, any depth of the recess section D formed in the vibrating portion R1 may be used.
(41) 8. In each mode described above, although the configuration in which the portion of the vibration plate 65 in which the piezoelectric element 67 is formed is thinner in the thickness over the entire area than the fixing portion R2 is described as an example, the portion of the vibration plate 65 in which the piezoelectric element 67 is formed may partially be thinner in the thickness than the fixing portion R2. Note that, according to the configuration in which the portion of the vibration plate 65 in which the piezoelectric element 67 is formed is thinner in the thickness over the entire area than the fixing portion R2, in comparison with the configuration in which the portion of the vibration plate 65 in which the piezoelectric element 67 is formed is partially thin in the thickness, a more remarkable effect of ensuring the displacement amount of the vibrating portion R1 is obtained.
(42) 9. In each mode described above, although the configuration in which the vibrating portion R1 is thinner in the thickness over the entire area than the fixing portion R2 is described as an example, the vibrating portion R1 may partially be thinner in the thickness than the fixing portion R2. For example, a range in which the thickness is made to be smaller than that of the fixing portion R2 may arbitrarily be changed in accordance with the size of the piezoelectric element 67.
(43) 10. In each mode described above, although the liquid supply chamber C2 is configured of the filter chamber C21 and the throttle section C22, a specific configuration of the liquid supply chamber C2 is not limited to the above-described example. For example, the liquid supply chamber C2 may be configured only of the filter chamber C21.
(44) 11. In each mode described above, although the serial type liquid ejecting apparatus 100 that reciprocates the transport body 242 in which the liquid ejecting head 26 is mounted is described as an example, the invention can also be applied to a line type liquid ejecting apparatus in which the plurality of nozzles N is distributed over the entire width of the medium 12.
(45) 12. The liquid ejecting apparatus 100 described as an example in each mode described above may be employed in various types of apparatuses such as a facsimile machine, a copying machine, or the like, in addition to an apparatus dedicated to printing. Understandably, the application of the liquid ejecting apparatus according to the invention is not limited to printing. For example, the liquid ejecting apparatus that ejects a color material solution is used as a manufacturing apparatus for forming a color filter of a liquid crystal display device. Additionally, the liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming a wire or an electrode of a wiring substrate.