JP2008173787A - Liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head which can reduce a difference in delivering characteristics between nozzle openings in the same nozzle array. <P>SOLUTION: The recording head equipped with pressure chambers and a common ink chamber 17 delivers liquid droplets by the action of a pressure generating source such as a diaphragm set corresponding to the pressure chamber. A part of a partition wall which forms partitioning the common ink chamber 17 is constituted thinner than the other part to be a diaphragm part 28 long in a nozzle array direction. An island-shaped beam part 29 long in the nozzle array direction is formed on a surface of the diaphragm part 28. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head such as an ink jet recording head, and in particular, has a nozzle row in which a plurality of nozzle openings are arranged in a row, and the liquid stored in a common liquid chamber is passed through the pressure chamber through the nozzle opening. The present invention relates to a liquid ejecting head that can be ejected as droplets.

  As a representative liquid ejecting head capable of ejecting liquid as liquid droplets, for example, an ink jet printer that performs recording by ejecting and landing liquid ink on a recording medium (ejection target) such as recording paper Examples thereof include an ink jet recording head (hereinafter referred to as a recording head) mounted on (a kind of liquid ejecting apparatus, hereinafter referred to as a printer). In addition, color material ejection heads used in the manufacture of color filters such as liquid crystal displays, electrode material ejection heads used in the formation of electrodes such as organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), biochips ( There are bioorganic ejecting heads and the like used in the manufacture of biochemical elements.

  As a recording head which is a kind of the liquid ejecting head, a pressure chamber communicating with a nozzle opening, a common ink chamber (common liquid chamber) for introducing a liquid to be supplied to the pressure chamber, a common ink chamber and a pressure chamber are provided. An ink supply path (common liquid flow path) that communicates and supplies ink in the common ink chamber to the pressure chamber side is provided, and a drive means (pressure generation source) is operated to cause pressure fluctuation in the liquid in the pressure chamber. In some cases, the ink in the pressure chamber can be ejected from the nozzle opening as an ink droplet (a kind of droplet). As this recording head, there are various drive systems. For example, a pressure generating element such as a piezoelectric vibrator or a heating element is provided, and an ink droplet is ejected by operating the pressure generating element, or a pressure chamber is created by electrostatic force generated between opposing electrodes. There is a configuration in which an ink droplet is ejected by elastically deforming a partitioning elastic surface (vibrating plate) (Patent Document 1).

JP-A-11-115179

  By the way, the recording head described in Patent Document 1 has a nozzle row in which a plurality of nozzle openings are arranged, and ink is supplied from one common ink chamber to the one nozzle row. It is configured. When a pressure fluctuation occurs in the pressure chamber in order to eject ink droplets, the ink pressure flow generated by the pressure fluctuation is transmitted to the ink in the common ink chamber via the ink supply path. Then, pressure fluctuation occurs in the common ink chamber, and the vibration of the pressure flow is reflected by the ink in the common ink chamber and is transmitted to the ink in each pressure chamber via each ink supply path. This causes problems such as unstable discharge characteristics. For this reason, in this recording head, a pressure fluctuation buffer portion thinner than the other portions is formed on a part of the partition wall that defines the common ink chamber, and the pressure fluctuation buffer portion is provided with compliance. The ink pressure fluctuation in the common ink chamber is absorbed.

  However, it is difficult to absorb all the pressure fluctuations of the ink in the common ink chamber in a short time, and vibration (residual vibration) due to the pressure flow remaining without being absorbed is reflected in the common ink chamber and is reflected in each pressure chamber. Communicated. In addition, since the common ink chamber is long in the nozzle row direction, the pressure fluctuation buffer portion is deformed unevenly and vibrates particularly in the nozzle row direction when the ink pressure flow interferes in the common ink chamber. For this reason, non-uniform residual vibration is transmitted to the pressure chambers arranged in the nozzle row direction. As a result, there is a problem that the ejection characteristics of the nozzle openings in the same nozzle row become non-uniform.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid jet head capable of reducing a difference in ejection characteristics between nozzle openings in the same nozzle row. .

The liquid jet head of the present invention has been proposed in order to achieve the above object, and has a nozzle row in which a plurality of nozzle openings are arranged, a pressure chamber communicating with each nozzle opening, and each pressure A liquid ejecting head that discharges liquid droplets from the nozzle opening by the operation of a pressure generation source provided corresponding to the pressure chamber, and a common liquid chamber that stores liquid to be supplied to the chamber via a liquid supply path. ,
A part of the partition wall that defines the common liquid chamber is configured to be thinner than the other part to form a diaphragm portion that is long in the nozzle row direction,
An island-like beam portion elongated in the nozzle row direction is formed on the surface of the diaphragm portion.

Further, the liquid jet head of the present invention includes a nozzle forming substrate having a nozzle row in which a plurality of nozzle openings are arranged,
By sealing the opening of the concave portion formed on the surface with the nozzle forming substrate, a pressure chamber communicating with each nozzle opening is partitioned and liquid supplied to each pressure chamber via a liquid supply path is stored. A flow path forming substrate that partitions and forms a common liquid chamber;
With
A liquid ejecting head that ejects liquid droplets from the nozzle opening by operation of a pressure generation source provided corresponding to the pressure chamber;
The nozzle forming substrate is configured such that a part of a partition wall that defines the common liquid chamber is made thinner than the other part to be a diaphragm part elongated in the nozzle row direction, and the surface of the diaphragm part An island-shaped beam portion that is long in the nozzle row direction is formed thereon.

  According to these configurations, since the island-shaped beam portion that is long in the nozzle row direction is formed on the surface of the diaphragm portion, the rigidity of the diaphragm portion in the nozzle row direction is improved and can be bent unevenly. It can be suppressed. Therefore, when the pressure fluctuation at the time of droplet discharge is transmitted from each pressure chamber to the liquid in the common liquid chamber, the diaphragm part vibrates uniformly in the nozzle row direction and absorbs the pressure fluctuation of the liquid in the common liquid chamber. can do. Thereby, the residual vibration reflected from the common liquid chamber and transmitted to the liquid in each pressure chamber can be made substantially uniform. From this, it is possible to make the ejection characteristics of the droplets uniform in each nozzle opening communicating with each pressure chamber and constituting the nozzle row. That is, even if residual vibration occurs in the liquid in each pressure chamber, it is possible to reduce the difference in droplet discharge characteristics between the nozzle openings in the same nozzle row. As a result, the quality of the recording image quality can be improved.

  In each of the above configurations, it is preferable that the beam portion is formed on at least one of an outer surface and an inner surface of the diaphragm portion.

  In each of the above configurations, it is desirable that both end portions are formed in a state in which the beam portion extends to a position before reaching the end of the diaphragm portion in the nozzle row direction.

  According to the above configuration, since the compliance can be imparted also to the periphery of both end portions of the beam portion in the diaphragm portion, there is no possibility of causing trouble in absorbing the pressure fluctuation of the liquid in the common liquid chamber.

  In each of the above configurations, it is preferable to form a plurality of the beam portions.

  In each of the above configurations, it is preferable that the beam portion is formed integrally with the diaphragm portion by etching.

  According to the above configuration, there is no need to separately form a beam portion, and the step of forming only this beam portion can be omitted.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following description, an ink jet recording apparatus (ink jet printer: hereinafter referred to as a printer) will be described as an example of the liquid ejecting apparatus of the invention.

  FIG. 1 is a perspective view illustrating the basic configuration of the printer. As shown in FIG. 1, a printer 1 is provided with a recording head 2 that is a kind of liquid ejecting head, a carriage 4 to which an ink cartridge 3 is detachably attached, and a lower portion of the recording head 2. A platen 5, a carriage moving mechanism 7 for moving the recording head 2 (carriage 4) in the paper width direction of the recording paper 6 (a kind of discharge target), and a recording paper 6 in a paper feed direction that is a direction orthogonal to the head moving direction. And a paper feed mechanism 8 for conveying the paper. Here, the paper width direction is the main scanning direction, and the paper feed direction is the sub-scanning direction. The ink cartridge 3 may be a type that is mounted on the carriage 4 or a type that is mounted on the housing side of the printer 1 and is supplied to the recording head 2 via an ink supply tube. Hereinafter, the recording head 2 will be described.

  FIG. 2 is an exploded perspective view showing the configuration of the recording head of this embodiment, and FIG. 3 is a cross-sectional view of the recording head in the longitudinal direction of the pressure chamber. The recording head 2 (head chip) has a glass electrode substrate 14 on one surface of a flow path forming substrate 12 made of silicon, and a nozzle forming substrate 13 made of silicon on the other surface of the flow path forming substrate 12. Each is arranged and laminated, and each member is joined by an adhesive to form a three-layer structure.

  The nozzle forming substrate 13 is a silicon plate member having nozzle rows 15 ′ in which a plurality of nozzle openings 15 are opened in a row at a pitch (for example, 180 dpi) corresponding to the dot formation density. The channel forming substrate 12 is subjected to anisotropic etching from its surface to form a groove portion serving as an ink channel, and the opening portion of the groove portion is blocked by the nozzle forming substrate 13. A plurality of pressure chambers 16 corresponding to the respective nozzle openings 15, a common ink chamber 17 (corresponding to a common liquid chamber of the present invention) into which common ink is introduced into each pressure chamber 16, and a common ink chamber 17 And a series of ink flow paths comprising ink supply paths 18 (corresponding to the liquid supply paths of the present invention) communicating with the pressure chambers 16 are defined.

  In the flow path forming substrate 12, an ink introduction port 24 penetrating in the substrate thickness direction is provided on the bottom surface of the groove portion that is long in the nozzle row direction serving as the common ink chamber 17. Further, a diaphragm 19 that functions as an elastic surface that can be elastically displaced in the head stacking direction (vertical direction in FIG. 3) is formed on the bottom surface of the groove portion that becomes each pressure chamber 16. That is, the diaphragm 19 is configured to partition at least one surface of the pressure chamber 16. A common electrode terminal 20 is formed on the flow path forming substrate 12, and since the flow path forming substrate 12 has conductivity, the diaphragm 19 functions as a common electrode. Note that an insulating layer (not shown) made of inorganic glass is provided on the surface of the flow path forming substrate 12 to which the electrode substrate 14 is bonded. In the present embodiment, the flow path forming substrate 12 is manufactured by etching a Si substrate.

  The electrode substrate 14 is made of borosilicate glass. This borosilicate glass has a thermal expansion coefficient similar to that of silicon. For this reason, separation between the head constituent members due to temperature changes is difficult to occur. On the surface of the electrode substrate 14 that is bonded to the flow path forming substrate 12, a recess 14 a that is shallowly etched in a tray shape is formed at a position facing the vibration plate 19 of the pressure chamber 16 corresponding to each pressure chamber 16. Is formed. Individual electrodes 21 formed by laminating thin films such as indium tin oxide (ITO) are laid on the bottom surfaces of the recesses 14a. Each individual electrode 21 includes a segment electrode 21 a extending corresponding to each pressure chamber 16 and an electrode terminal portion 21 b exposed to the outside. When the electrode substrate 14 is joined to the flow path forming substrate 12, the diaphragm 19 of each pressure chamber 16 and the segment electrode 21a of each individual electrode 21 face each other in a state where a narrow gap is formed. This gap is sealed by the sealing material 22 and is in a sealed state.

  The electrode substrate 14 is formed with an ink introduction path 23 penetrating in the substrate thickness direction. The ink introduction path 23 communicates with the ink introduction port 24 in a joined state with the flow path forming substrate 12. It is like that. For example, ink from an ink tank (not shown) provided on the printer 1 side is introduced into the common ink chamber 17 through the ink introduction path 23 and the ink introduction port 24. The ink in the common ink chamber 17 is distributed and supplied to each pressure chamber 16 through an ink supply path 18 branched from the common ink chamber 17. The ink in each pressure chamber 16 is supplied to a nozzle opening 15 communicating with the pressure chamber 16. That is, in the present embodiment, the ink is supplied to one common ink chamber 17 corresponding to one nozzle row 15 ′.

  A drive voltage supply source 25 is electrically connected between the common electrode terminal 20 of the flow path forming substrate 12 and the individual electrode 21 of the electrode substrate 14. A driving voltage is applied between each individual electrode 21 and the common electrode terminal 20 by the driving voltage supply source 25. As a result, an electrostatic force is generated between the diaphragm 19 functioning as a common electrode and the individual electrode 21, and by this electrostatic force, the diaphragm 19 is elastically deformed and bent toward the individual electrode 21 side, and the surface of the segment electrode 21a Adsorb to. As a result, the volume of the pressure chamber 16 increases and ink flows into the pressure chamber 16 from the common ink chamber 17 side through the ink supply path 18. When the driving voltage from the driving voltage supply source 25 is not applied and the electrostatic force is released, the diaphragm 19 is separated from the surface of the segment electrode 21a by the elastic force and returns to the initial state. As a result, the volume of the pressure chamber 16 is rapidly reduced. As a result, a pressure fluctuation occurs in the ink in the pressure chamber 16, and a part of the ink in the pressure chamber 16 is ejected as an ink droplet from the nozzle opening 15 due to the pressure fluctuation. That is, the diaphragm 19, the common electrode terminal 20, the individual electrode 21, and the drive voltage supply source 25 function as a pressure generation source in the present invention.

  Here, the nozzle forming substrate 13 in the recording head 2 of the present embodiment is configured such that a part of the partition wall that partitions the common ink chamber 17 is thinner than the other part, and this thin part is formed in the nozzle row direction. A long diaphragm portion 28 is provided. An island-shaped beam portion 29 that is long in the nozzle row direction is formed together with the diaphragm portion 28 on the surface of the diaphragm portion 28 opposite to the flow path forming substrate 12 side. 4A is a plan view for explaining the diaphragm portion of the nozzle forming substrate, FIG. 4B is a cross-sectional view in the AA direction of FIG. 5A, and FIG. 5 is a diagram of the diaphragm portion of the nozzle forming substrate. It is sectional drawing of the AA direction of Fig.4 (a) explaining a vibration state. Hereinafter, the diaphragm portion 28 and the beam portion 29 will be described in detail.

  As shown in FIGS. 2 to 4, the diaphragm portion 28 is a substantially rectangular (or parallelogram-shaped) region that is long in the nozzle row direction so as to correspond to the opening surface of the groove portion that becomes the common ink chamber 17. In the present embodiment, the nozzle forming substrate 13 in a region facing the opening surface of the groove serving as the common ink chamber 17 is formed by partially removing the thickness by anisotropic etching. The diaphragm portion 28 is formed integrally with the above-described groove portion serving as the other ink flow path, the nozzle opening 15 and the like, and a part of the region serving as the partition wall for partitioning and forming the common ink chamber 17 is thinned. Have sex. As a result, it functions as a damper that absorbs ink pressure fluctuations in the common ink chamber 17. Further, in the diaphragm portion 28, an island-like beam portion 29 that is long in the nozzle row direction is formed on the surface opposite to the flow path forming substrate 12 side, that is, on the outer surface of the common ink chamber 17. is doing. The beam portion 29 is formed in a state in which both side edges in the longitudinal direction are separated from the side edges of the diaphragm portion 28 and both end portions thereof extend to a position before reaching the end of the diaphragm portion 28 in the nozzle direction. That is, the diaphragm portion 28 has a beam portion 29 at the center in the width direction, and is configured by a thin region surrounding the beam portion 29. As a result, compliance can be imparted to the periphery of both end portions of the beam portion 29 in the diaphragm portion 28, so that there is no possibility of hindering the absorption of ink pressure fluctuations in the common ink chamber 17. In addition, the beam part 29 in this embodiment is integrally formed with the diaphragm part 28 by different direction etching like other parts. Therefore, there is no need to separately form the beam portion 29, and the step of forming only the beam portion 29 can be omitted.

  Further, when the pressure fluctuation at the time of ink droplet ejection is transmitted from each pressure chamber 16 to the ink in the common ink chamber 17, the ink in the common ink chamber 17 vibrates, and as shown in FIG. The diaphragm portion 28 vibrates up and down. At this time, the diaphragm portion 28 of the present embodiment is formed with island-like beam portions 29 that are long in the nozzle row direction on the surface thereof, so that the rigidity in the nozzle row direction is improved and flexed unevenly. It can be suppressed. Therefore, the diaphragm portion 28 can vibrate uniformly in the nozzle row direction and can absorb ink pressure fluctuation in the common ink chamber 17. Thereby, the residual vibration reflected from the common ink 17 chamber and transmitted to the ink in each pressure chamber 16 can be made substantially uniform. From this, it is possible to make the ejection characteristics of the ink droplets ejected from each nozzle opening 15 constituting one nozzle row 15 'uniform. That is, even if residual vibration is generated in the ink in each pressure chamber 16, the difference in the ink droplet ejection characteristics between the nozzle openings 15 in the same nozzle row 15 ′ can be reduced. As a result, the ejection characteristics of each nozzle row 15 ′ in the recording head 2 can be made uniform. Therefore, the landing position deviation of the ink droplets can be reduced, the recording unevenness can be suppressed, and the quality of the recording image quality can be improved.

  By the way, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the description of the scope of claims. The beam portion 29 is illustrated as being formed on the outer surface of the diaphragm portion 28 (common ink chamber 17), but is not limited thereto, and may be formed on at least one of the outer surface and the inner surface of the diaphragm portion 28. For example, as shown in FIG. 6A, a beam portion 29 that is long in the nozzle row direction may be formed on the inner surface of the diaphragm portion 28 (common ink chamber 17), or in FIG. As shown, the diaphragm 28 (common ink chamber 17) may be formed on both the inner and outer surfaces. In short, any shape may be used as long as the beam portion 29 can be provided to improve the rigidity so that the diaphragm portion 28 vibrates uniformly in the nozzle row direction.

  Moreover, although the example which formed the one beam part 29 in the diaphragm part 28 was shown in the said embodiment, not only this but the beam part 29 may be divided | segmented into several and formed. For example, as shown in FIG. 7A, three nozzles may be arranged in series in the nozzle row direction, and as shown in FIG. 7B, two in parallel in the direction orthogonal to the nozzle row direction. They may be formed side by side. As described above, according to the present invention, the beam portion 29 may be provided so that the diaphragm portion 28 vibrates uniformly in the nozzle row direction. Therefore, the arrangement relation, shape, and number of the outer surface and the inner surface of the diaphragm portion 28 are appropriately set. Can be set in combination.

  In the above embodiment, the diaphragm portion 28 as a part of the partition wall that seals the groove portion that becomes the common ink chamber 17 of the flow path forming substrate 12 and the beam portion 29 formed on the surface of the diaphragm portion 28 are provided. Although an example in which the nozzle forming substrate 13 made of a silicon plate material is partially removed by etching has been shown, the present invention is not limited to this. For example, an elastic plate in which an elastic film made of PP (polypropylene) or the like is laminated on the surface of a support plate made of stainless steel or the like is partially removed by etching, and a beam made of a support plate is formed on a diaphragm portion made only of the elastic film. A part may be formed.

  In the above description, the ink jet recording head 2 is described as an example of the liquid ejecting head mounted on the liquid ejecting apparatus. However, the present invention provides a common ink chamber (common liquid chamber) in which a plurality of pressure chambers communicate with each other. Any other liquid ejecting head can be used as long as it has such a structure. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, an FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

FIG. 3 is a perspective view illustrating a basic configuration of a printer. FIG. 3 is an exploded perspective view illustrating the configuration of a recording head to which the invention is applied. FIG. 4 is a cross-sectional view of the recording head in the longitudinal direction of the pressure chamber. (A) is a top view explaining the diaphragm part of a nozzle formation board | substrate, (b) is sectional drawing of the AA direction of (a). It is sectional drawing of the AA direction of Fig.4 (a) explaining the vibration state of the diaphragm part of a nozzle formation board | substrate. It is sectional drawing of the AA direction of Fig.4 (a) which shows the modification of the beam part of a diaphragm part. It is a top view which shows the modification of the beam part of the diaphragm part in a nozzle formation board | substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 3 ... Ink cartridge, 4 ... Carriage, 5 ... Platen, 6 ... Recording paper, 7 ... Carriage moving mechanism, 8 ... Paper feed mechanism, 12 ... Channel formation board, 13 ... Nozzle formation Substrate, 14 ... electrode substrate, 14a ... recess, 15 ... nozzle opening, 16 ... pressure chamber, 17 ... common ink chamber, 18 ... ink supply path, 19 ... diaphragm, 20 ... common electrode terminal, 21 ... individual electrode, 21a ... Segment electrode, 21b ... Electrode terminal part, 22 ... Sealing material, 23 ... Ink introduction path, 24 ... Ink introduction port, 25 ... Drive voltage supply source, 28 ... Diaphragm part, 29 ... Beam part

Claims (6)

A nozzle row having a plurality of nozzle openings arranged in a row, and a pressure chamber that communicates with each nozzle opening and a common liquid chamber that stores liquid to be supplied to each pressure chamber via a liquid supply path. A liquid ejecting head that ejects liquid droplets from the nozzle opening by operation of a pressure generation source provided corresponding to the chamber;
A part of the partition wall that defines the common liquid chamber is configured to be thinner than the other part to form a diaphragm portion that is long in the nozzle row direction,
A liquid ejecting head, wherein an island-like beam portion elongated in the nozzle row direction is formed on a surface of the diaphragm portion. A nozzle forming substrate having a nozzle row in which a plurality of nozzle openings are arranged;
By sealing the opening of the concave portion formed on the surface with the nozzle forming substrate, a pressure chamber communicating with each nozzle opening is partitioned and liquid supplied to each pressure chamber via a liquid supply path is stored. A flow path forming substrate that partitions and forms a common liquid chamber;
With
A liquid ejecting head that ejects liquid droplets from the nozzle opening by operation of a pressure generation source provided corresponding to the pressure chamber;
The nozzle forming substrate is configured such that a part of a partition wall that defines the common liquid chamber is made thinner than the other part to be a diaphragm part elongated in the nozzle row direction, and the surface of the diaphragm part A liquid ejecting head having an island-like beam portion elongated in the nozzle row direction formed thereon.   The liquid jet head according to claim 1, wherein the beam portion is formed on at least one of an outer surface and an inner surface of the diaphragm portion.   4. The liquid jet according to claim 1, wherein both ends of the beam portion are formed so as to extend to a position before reaching the end in the nozzle row direction of the diaphragm portion. 5. head.   The liquid jet head according to claim 1, wherein a plurality of the beam portions are formed.   The liquid jet head according to claim 1, wherein the beam portion is integrally formed with the diaphragm portion by etching.

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