JP2005233029A - Electrostatic actuator, droplet delivery head, image forming device and micropump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator capable of high density arrangement, and providing a stable operation characteristic. <P>SOLUTION: This electrostatic actuator is constituted for deforming a vibrating plate 11 by electrostatic force between the vibrating plate 11 and an electrode 13, by arranging the vibrating plate 11 and the electrode 13 opposed to this plate via a gap 12 on a wall surface of an inter-liquid chamber partition wall 8 between pressurized liquid chambers 4 and 4, that is, both wall surfaces of the pressurized liquid chambers 4. The gap 12 is formed by removing a sacrifice layer formed between the vibrating plate 11 and the electrode 13 by etching via a sacrifice layer removing hole 14 formed in the vibrating plate 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrostatic actuator, a droplet discharge head, an image forming apparatus, and a micropump.

  For example, an ink jet head used in an ink jet recording apparatus used as an image forming apparatus such as a printer, a facsimile machine, a copying machine, or a plotter has a nozzle that ejects ink droplets and a liquid chamber (discharge chamber, pressure chamber, pressure chamber) that communicates with the nozzle. Pressure chamber, also referred to as an ink flow path) and actuator means for generating energy for pressurizing the ink in the liquid chamber, and generating pressure to apply pressure to the ink in the liquid chamber. Ink droplets are ejected from the nozzles.

  As an ink jet head, one using a piezoelectric actuator such as an electromechanical transducer, one using a thermal actuator utilizing film boiling as an electrothermal transducer, or an electrostatic utilizing an electrostatic force between a diaphragm and an electrode. Ink jet heads using electrostatic actuators are superior to other types of heads in terms of size reduction, speed, density, and power saving. Currently, development is actively underway.

As an ink jet head using such an electrostatic actuator, an electrode substrate on which individual electrodes are formed, a flow path substrate on which a liquid chamber and an individual electrode are opposed to each other via a gap (gap), and a nozzle What is comprised by the laminated structure with the nozzle board | substrate which formed this is known.
Japanese Patent Laid-Open No. 6-71882

  In this electrostatic ink jet head, a diaphragm is formed on one surface (bottom surface) of a liquid chamber communicating with a nozzle, an individual electrode is disposed opposite to the diaphragm, and a drive pulse voltage is applied between the diaphragm and the individual electrode. By applying voltage, the diaphragm is deformed by the electrostatic force generated between the individual electrode and the diaphragm, and the diaphragm is restored by deforming by removing the voltage. To discharge.

  By the way, in order to perform high-density and high-quality recording using an inkjet head, it is necessary to form nozzle holes for discharging droplets at high density.

  However, in the electrostatic ink jet head having the above-described structure, since the diaphragms are arranged along the direction in which the liquid chambers are arranged, if the liquid chambers are arranged with high density in order to arrange the nozzles with high density, There is a problem that the area of the diaphragm is reduced, and a required diaphragm displacement cannot be obtained by low voltage driving.

Therefore, by forming a diaphragm and a gap on the wall surface of the partition wall (liquid chamber interval wall) between the liquid chambers (flow channels) formed on the flow path forming member such as the liquid chamber substrate, the nozzles can be arranged with high density. Inkjet heads are known.
JP 2002-316418 A JP 2002-25226 A

  In such a head, as a method of forming a diaphragm and a gap in the liquid chamber interval wall of the liquid chamber substrate, the above-mentioned Patent Document 2 uses (1) anisotropic etching and thermal oxidation of a single crystal silicon substrate. (2) A recess is formed from both the electrode side and the liquid chamber side of the substrate by etching. A method is disclosed in which a portion sandwiched between the recesses is used as a diaphragm, and a gap is formed by contraction of a member filled in the electrode recesses.

  Patent Document 3 discloses a method of forming a digging to be a gap by anisotropically etching a single crystal silicon substrate, leaving a portion to be a diaphragm from a wall surface of a recess to be a liquid chamber. Yes.

  However, in the inkjet head in which the diaphragm and the gap are formed on the liquid chamber interval wall of the liquid chamber substrate as described above, the liquid chamber substrate and the diaphragm member are separately formed, and the diaphragm member is attached to the wall surface of the liquid chamber substrate. If a gap is pasted, a high-precision gap cannot be formed, and recesses are formed on both the electrode side and the liquid chamber side of the substrate by etching, and a portion sandwiched between the recesses is formed. If the gap is formed by contraction of the member filled in the electrode concave portion with the diaphragm, there is a problem that the diaphragm cannot be formed with high accuracy.

  In addition, when forming a digging that becomes a gap while leaving a portion that becomes a vibration plate by anisotropic etching of a single crystal silicon substrate, a long gap in the depth direction must be formed by etching. It takes time, and it is difficult to form the diaphragm and the gap with high precision because it is difficult to perform etching with the same width with the same width because of side etching. There is.

  As a result, there is a problem that the droplet ejection characteristics of the head fluctuate and high-quality image formation cannot be performed.

  The present invention has been made in view of the above-described problems, and is an electrostatic actuator capable of high-density arrangement and capable of obtaining stable operation characteristics, small size, low-cost high-density arrangement, and stable droplet discharge. To provide a droplet discharge head capable of obtaining characteristics, an image forming apparatus capable of forming a high-quality image equipped with this droplet discharge head, and a micropump including the electrostatic actuator and capable of stable liquid transport Objective.

  The electrostatic actuator according to the present invention has a configuration in which a vibration plate is provided on the wall surface of the liquid chamber interval wall, and a gap between the vibration plate and the electrode is formed by a sacrificial layer etching process. In this specification, the liquid chamber interval wall is used to include a partition that separates the liquid chamber from the outside.

  Here, it is preferable that the sacrificial layer removal hole for removing the sacrificial layer is formed in a portion corresponding to a surface of the liquid chamber interval wall that does not form the liquid chamber wall surface. In addition, it is preferable that at least one surface of the liquid chambers forming the wall surface of the liquid chamber interval wall in the arrangement direction is an inclined surface.

  Furthermore, it is preferable that a diaphragm is provided on each of the opposing wall surfaces of the liquid chamber. And it is preferable that the deformable area | region of a diaphragm is smaller than the wall surface area | region of a liquid chamber space | interval wall.

  In addition, it is preferable that a communication path that communicates gaps corresponding to the diaphragms is provided. Furthermore, it is preferable that a plurality of communication paths are provided.

  The liquid droplet ejection head according to the present invention includes the electrostatic actuator according to the present invention.

  An image forming apparatus according to the present invention is equipped with a droplet discharge head according to the present invention.

  The micropump according to the present invention includes the electrostatic actuator according to the present invention.

  According to the electrostatic actuator according to the present invention, the diaphragm is provided on the wall surface of the liquid chamber interval wall, and the gap between the diaphragm and the electrode is formed by the sacrificial layer etching process. A gap (air gap) can be formed, high-density arrangement becomes possible, and stable operating characteristics can be obtained.

  According to the droplet discharge head according to the present invention, since the electrostatic actuator according to the present invention is provided, stable droplet discharge characteristics capable of high-density recording can be obtained, and the head member can be downsized and reduced. Cost can be reduced.

  According to the image forming apparatus of the present invention, since the liquid droplet ejection head according to the present invention is provided, high image quality recording can be performed with low power consumption.

  According to the micropump according to the present invention, since the electrostatic actuator according to the present invention is provided, efficient liquid movement can be stably performed with low power consumption.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a first embodiment of a droplet discharge head according to the present invention including an electrostatic actuator according to the present invention will be described with reference to FIGS. 1 is a schematic perspective explanatory view showing the head disassembled, FIG. 2 is a plan explanatory view showing the head viewed from the nozzle plate side, and FIG. 3 is a plan view showing extracted patterns of each part of FIG. 4 is a cross-sectional explanatory view taken along line X1-X1 in FIG. 2, FIG. 5 is a cross-sectional explanatory view taken along line X2-X2 in FIG. 2, and FIG. 6 is a cross-sectional explanatory view taken along line Y1-Y1 in FIG. 7 is a cross-sectional explanatory view taken along the line Y2-Y2 of FIG. 2, and FIG. 8 is a cross-sectional explanatory view taken along the line Y3-Y3 of FIG.

  This droplet discharge head is configured by laminating a flow path / actuator substrate 1 and a nozzle substrate 2. The flow path / actuator substrate 1 is previously formed with recesses that serve as a pressurized liquid chamber 4, a fluid resistance portion 5, a common liquid chamber 6, and the like, and a nozzle hole 3 is formed in the nozzle substrate 2.

  By joining the flow path / actuator substrate 1 and the nozzle substrate 2, liquid (ink) is supplied to the pressurized liquid chamber 4 and the pressurized liquid chamber 4 through which the nozzle holes 3 for discharging droplets formed on the nozzle substrate 2 communicate. The fluid resistance portion 5 and the common liquid chamber 6 are formed. Each pressurized liquid chamber 4 is partitioned by a liquid chamber interval wall 8. A liquid supply port 7 for supplying a liquid to the common liquid chamber 6 is formed in advance from the back surface of the flow path / actuator substrate 1 through the substrate.

  In addition, although the fluid resistance part 5 shown in FIG. 1 is not restrict | squeezed, the width | variety and height can be restrict | squeezed. The liquid chamber interval wall 8 separating the pressurized liquid chamber 4 is formed substantially perpendicular to the horizontal direction of the flow path / actuator substrate 1, and the wall surface of the liquid chamber interval wall 8 is a vertical surface 8a.

  And the wall surface of the liquid chamber space | interval wall 8 (as shown also in FIG.4 and FIG.5 on the wall surface of the liquid chamber in the alignment direction of a liquid chamber, arrange | positions the diaphragm 11 and this with the gap (space | gap) 12 facing. An actuator element 10 which is an electrostatic actuator according to the present invention configured with an electrode 13 (this is referred to as a “fixed electrode 13”) is disposed, in which case the liquid chamber of one pressurized liquid chamber 4 The actuator elements 10 are arranged on the wall surfaces 8a and 8a of the liquid chamber interval walls 8 and 8 in the arrangement direction.

  Here, the gap 12 between the diaphragm 11 and the fixed electrode 13 is formed by etching the sacrificial layer formed between the diaphragm 11 and the fixed electrode 13 through the sacrificial layer removing hole 14 formed in the diaphragm 11. It is formed by removing with. The sacrificial layer removal hole 14 is formed on the surface of the liquid chamber interval wall 8 where the liquid chamber wall surface is not formed, here, the bonding surface with the nozzle substrate 2, and the flow path / actuator substrate 1 and the nozzle substrate 2 are bonded to each other. When joining, the sacrificial layer removal hole 14 is sealed with an adhesive so that liquid or the like does not enter the gap 12. Further, the sacrificial layer removal hole 14 and the gap 12 are communicated with each other through a communication path (gap) 12a.

  In FIG. 2, only two nozzles are shown for convenience, but in actuality, a larger number of nozzles are arranged. In addition, although only five sacrificial layer removal holes 14 are drawn per wall surface of the pressurized liquid chamber 4, in actuality a large number (for example, a pitch of 10 to 50 μm. When the pressurized liquid chamber length is 1000 μm, per wall surface (100 to 20) are preferably arranged. The same applies to the following drawings.

  Further, in this head, the fixed electrode 13 is provided as an individual electrode for each nozzle (pressure liquid chamber) and is provided separately, and the vibration plate 11 is electrically used as a common electrode at each nozzle (pressure liquid chamber). The nozzle 3 to be ejected is selected according to the presence or absence of a drive voltage applied to the fixed electrode 13 in common.

  The fixed electrode 13 is provided so as to extend from the pressurized liquid chamber 4 to the flat surface of the surface of the flow path / actuator substrate 1, and an electrode take-out pad 15A and an electrode connection hole 16A of the fixed electrode 13 are formed on the flat surface portion. ing. The vibration plate 11 is also provided to extend from the pressurized liquid chamber 4 to the flat surface of the surface of the flow path / actuator substrate 1, and an electrode take-out pad and an electrode connection hole for a vibration plate electrode are formed on the flat surface portion, although not shown. ing.

  Thus, according to the electrostatic actuator according to the present invention, the diaphragm is provided on the wall surface of the liquid chamber interval wall, and the gap between the diaphragm and the electrode is formed by the sacrificial layer etching process. Since the diaphragm and the gap can be formed, high-density arrangement is possible and stable operation characteristics can be obtained. By configuring a droplet discharge head including this electrostatic actuator, stable liquid discharge characteristics can be obtained. As a result, high-density recording can be performed stably.

  Here, the flow path / actuator substrate 1 is formed by, for example, growing a thermal oxide film serving as an anisotropic etch mask layer on a silicon substrate having a crystal plane orientation (110), and forming a portion serving as a liquid chamber / flow path as a photolithography process.・ Open by etching process, and then perform anisotropic etching of silicon with KOH aqueous solution or TMAH aqueous solution, and then remove the thermal oxide film used as anisotropic etch mask with buffered hydrofluoric acid etc. can do.

  The nozzle substrate 2 is formed of a metal plate such as Ni or SUS, ceramics, glass, or resin, and the nozzle hole 3 can be formed by a known method such as dry or wet etching or laser processing. A water repellent film is formed on the discharge direction surface of the nozzle substrate 2 by a known method such as a plating film or a water repellent coating in order to ensure water repellency with ink.

  The droplet discharge of the droplet discharge head according to the present invention is configured as a so-called side shooter (face shooter) that discharges from a nozzle hole 3 formed in the nozzle substrate 2 in a direction substantially perpendicular to the nozzle substrate surface. ing.

  Next, details of the configuration of the above-described droplet discharge head will be described with reference to FIGS. 9 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall along the X1-X1 line of FIG. 2, FIG. 10 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall along the X2-X2 line of FIG. 2 is an enlarged cross-sectional view of the upper portion of the liquid chamber interval wall along the line Y3-Y3, FIG. 12 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the nozzle arrangement direction, and FIG. 13 is an additional view along the line Y1-Y1 of FIG. 14 is an enlarged cross-sectional view of the bottom of the hydraulic fluid chamber, FIG. 14 is a cross-sectional explanatory view of a fixed electrode electrode take-out pad portion along line Y1-Y1 in FIG. 2, and FIG. 15 is not shown in FIG. It is a cross-sectional explanatory view of the take-out pad portion.

  As described above, the diaphragm 11 and the gap 11 formed by etching the diaphragm 11 and the sacrificial layer are formed on the wall surfaces 8a and 8a of the liquid chamber interval walls 8 and 8 facing each other in the pressurized liquid chamber 4. And an opposing fixed electrode 13 to form an actuator element 10 that is an electrostatic actuator according to the present invention.

  Here, the diaphragm 11 is composed of four layers of a diaphragm-side insulating film 18, a diaphragm electrode 19, a stress adjustment film 20 and a diaphragm crack prevention film 21, and each has a desired rigidity. The film thickness is adjusted.

  The diaphragm insulating film 18 has a function of preventing a short circuit between the diaphragm electrode 19 and the fixed electrode 13 and protecting the diaphragm electrode 19 when the sacrificial layer is removed. The electrode layer 13 is resistant to sacrificial layer etching. Effective when there is no or low. For example, polysilicon can be used as a material for the sacrificial layer and the diaphragm electrode 19. When this material is used, the electrode layer 19 needs to be covered with a protective film when the sacrificial layer is removed. Further, as the material of the diaphragm electrode layer 19, for example, doped polysilicon can be used.

  The stress adjustment film 20 is, for example, a nitride film, cancels compressive stress such as an oxide film or a polysilicon film, and the vibration plate 11 bends in an initial state (a state where no voltage is applied between the fixed electrode 13). It has a function to prevent it.

  The diaphragm crack prevention film 21 is an oxide film, for example, and has a function of preventing the diaphragm 11 from cracking. That is, when the outermost surface of the vibration plate 11 is a nitride film, there arises a problem that the vibration plate 11 is easily broken during processing by the sacrificial layer etching process or during the operation of the head after completion of the head. By forming the oxide film, the diaphragm can be prevented from cracking.

  Here, in the vicinity of the sacrificial layer removal hole 14, as shown in FIGS. 9 and 11, the opening diameter of the diaphragm electrode 19 is larger than the diameter of the sacrificial layer removal hole 14 so that the surface of the diaphragm electrode 19 is not exposed. The opening edge of the diaphragm electrode 19 is covered with the stress adjusting film 20 and the diaphragm crack preventing film 21.

  On the other hand, since the fixed electrode 13 is an individual electrode corresponding to each nozzle 3, as shown in FIGS. 9 and 10, the separation groove 13A is formed on the liquid chamber interval wall 8 on the upper surface (joining surface with the nozzle substrate 2) side. Are formed separately. Then, a fixed electrode side insulating film 22 is formed on the surface of the fixed electrode 13 on the gap 12 side including a separation groove between the fixed electrodes 13, and an insulating film 23 is formed on the liquid chamber interval wall 8 side.

  Here, the gap 12 formed between the fixed electrode side insulating film 22 and the diaphragm side insulating film 18 is formed only in a predetermined region so that the diaphragm 11 can be deformed. The side insulating film 22 and the diaphragm side insulating film 18 are in close contact with each other to form the diaphragm fixing portion 25 at the bottom of the pressurized liquid chamber 4 or the like. This configuration is determined by the presence or absence of a sacrificial layer pattern to be described later.

Further, the nozzle substrate 2 is bonded and bonded onto the flow path / actuator substrate 1 via the adhesive layer 17, and the sacrificial layer removal hole 14 is sealed by the nozzle substrate 2 and the adhesive layer 17. Thus, by forming the sacrificial layer removal hole in a portion corresponding to the surface of the liquid chamber interval wall that does not form the liquid chamber wall surface, the sacrificial layer removal hole can be easily sealed. Further, since the sacrificial layer removal holes can be formed with high density and high accuracy, the sacrificial layer can be removed with high efficiency and low variation.

  Further, as shown in FIG. 14, the electrode connection holes 16A are opened in the fixed electrode side insulating film 22, the diaphragm side insulating film 18, the diaphragm electrode 19, the stress adjusting film 20, and the diaphragm crack preventing film 21, for example, An electrode extraction pad 15A for the fixed electrode 13 is formed of Al, Al—Si, Al—Si—Cu, or the like.

  Similarly, as shown in FIG. 15, an electrode connection hole 16B is opened in the stress adjusting film 20 and the diaphragm crack prevention film 21, and the diaphragm electrode 19 is made of, for example, Al, Al—Si, Al—Si—Cu, or the like. The electrode extraction pad 15B is formed.

  Next, another example of the first embodiment will be described with reference to FIGS. 16 is an enlarged cross-sectional view of the upper portion of the liquid chamber interval wall corresponding to the cross section taken along line X1-X1 in FIG. 2, and FIG. 17 is an upper view of the liquid chamber interval wall corresponding to the cross section taken along line X2-X2 of FIG. FIG. 18 is an enlarged cross-sectional view, and FIG. 18 is an enlarged cross-sectional view of the upper portion of the liquid chamber interval wall along the line Y3-Y3 in FIG.

  In this example, a sacrificial layer 24 that is not removed by the sacrificial layer etching process is formed in a region where the diaphragm 11 above the liquid chamber interval wall 8 is fixed, so that the upper portion of the liquid chamber interval wall 8 (the bonding surface with the nozzle substrate). Is made flatter. By adopting such a configuration, it is possible to improve the bonding degree of the constituent members (here, the flow path / actuator substrate 1 and the nozzle substrate 2). Other configurations are the same as described above.

  Here, after the sacrificial layer is formed on the fixed electrode 13, the sacrificial layer 24 is separated in advance from the region to be left and the region to be the gap 12, and the sacrificial layer removal hole 14 is not provided in the remaining portion. Can be obtained.

  Next, still another example of the first embodiment will be described with reference to FIGS. 19 and 20. 19 is a cross-sectional explanatory view of the bottom of the pressurizing liquid chamber along the nozzle arrangement direction, and FIG. 20 is an enlarged cross-sectional view of the bottom of the pressurizing liquid chamber along the Y1-Y1 line of FIG.

  In this example, the fixed electrode 13 is not formed on the bottom surface of the pressurized liquid chamber 4. Accordingly, if the depth of the concave portion (digging) for forming the pressurized liquid chamber 4 is the same, the volume of the pressurized liquid chamber 4 can be relatively increased, and the pressurized liquid chamber 4 Can be made thinner, the thickness of the flow path / actuator substrate 1 can be reduced. In addition, since there is no capacitance between the fixed electrode and the diaphragm and between the fixed electrode and the substrate at the bottom portion of the pressurized liquid chamber 4, the capacitance of the fixed electrode is reduced, thereby reducing the driver IC and the like. The load on the driving circuit is reduced.

  Next, an example of a manufacturing method of the droplet discharge head according to the first embodiment will be described with reference to FIGS. 21A to 28A are cross-sectional explanatory views of the liquid chamber interval wall portion along line X1-X1 in FIG. 2, and FIGS. 21A to 28B are Y1 in FIG. It is sectional explanatory drawing of the electrode extraction pad 15A periphery along a -Y1 line. In the following, the supplementary notes (a) and (b) are omitted.

  First, as shown in FIG. 21, a thermal oxide film serving as an anisotropic etch mask layer is grown on a silicon substrate having a crystal plane orientation (110) serving as a flow path / actuator substrate 1, and a liquid chamber / flow path This part is opened by a photolithographic etching process. Thereafter, anisotropic etching of silicon is performed using a KOH solution or a TMAH aqueous solution to form liquid chambers such as the pressurized liquid chamber 4, the fluid resistance portion 5, and the common liquid chamber 6, and concave portions that serve as flow paths. The thermal oxide film used as the anisotropic etch mask is removed with buffered hydrofluoric acid or the like to obtain the flow path / actuator substrate 1 having the liquid chamber interval walls 8 and the like.

  At this time, since the crystal plane orientation (111) plane appears by performing anisotropic etching, by selecting the pattern direction, the liquid chamber interval wall 8 corresponding to the adjacent nozzle is defined in the flow path / actuator substrate 1. Can be formed substantially perpendicular to the surface of the substrate.

  Next, as shown in FIG. 22, a thermal oxide film as a substrate insulating film 23 is formed to a thickness of 1.6 μm on the surface of the flow path / actuator substrate 1 in which the liquid chambers and flow paths are formed, and the fixed electrode 13 is formed to a thickness of about 0.4 μm, and a separation groove 13A is formed in the phosphorus-doped polysilicon by a photolithography / etching process, and the fixed electrode 13 corresponding to each liquid chamber 4 is formed by patterning. To do.

  Next, as shown in FIG. 23, a CVD oxide film having a thickness of about 0.2 μm is formed on the patterned fixed electrode 13 as the fixed electrode side insulating film 22. This oxide film has a function of protecting the fixed electrode 13 from the etchant when the sacrificial layer 24 is removed later, and preventing a short circuit with the diaphragm electrode 19 when the head is driven.

  Thereafter, polysilicon is deposited to a thickness of about 0.3 μm as the sacrificial layer 24, and the gap 12 and the communication path 12a are patterned by photolithography and etching processes. The portion where the gap 12 is formed is determined by the pattern and the arrangement of the sacrificial layer removal hole 14 at this time.

  Next, as shown in FIG. 24, a CVD oxide film having a thickness of about 0.2 μm is formed on the patterned sacrificial layer 24 as the diaphragm-side insulating film 18. This oxide film has a function of protecting the fixed electrode 13 from the etchant when the sacrificial layer 24 is removed later, and preventing a short circuit with the fixed electrode 13 when the head is driven.

  Thereafter, 0.2 μm of phosphorus-doped polysilicon is deposited as the diaphragm electrode 19 and patterned by a photolithographic etching process.

  Next, as shown in FIG. 25, a CVD nitride film is formed as a stress adjusting film 20 on the patterned diaphragm electrode 19 to a thickness of about 0.15 μm, and a CVD cracking film 21 is formed thereon as a CVD crack prevention film 21. An oxide film is formed to a thickness of about 0.4 μm. Thereafter, a resist mask 26 is formed by a photolithography process in order to open the sacrificial layer removal hole 14 and the electrode pad connection hole 16A in these CVD nitride film and CVD oxide film.

  In this step, if the resist 26 is applied so as to completely cover the stepped structure, the concave portion of the pressurized liquid chamber 4 and the like is often filled with the resist. At this time, even if the resist 26 is not completely buried, the thickness of the resist 26 is thin in the portion that was the surface of the substrate first, and the thickness of the resist 26 is thick in the low portion as seen from the surface of the substrate such as the bottom of the pressurized liquid chamber 4. Become. On the other hand, regarding the relationship between the thickness of the resist 26 and the patterning dimension, when the thickness of the resist 26 is increased, the resolution is decreased (the minimum processing dimension is increased) and the dimensional variation tends to be increased.

  As for the exposure, when exposure is performed by a projection exposure apparatus, patterning with high accuracy can be performed when the patterning surface is generally flat because of focusing. Here, when using an exposure apparatus that does not use a projection optical system, that is, a so-called general aligner, the depth of focus can be made very deep, but high resolution cannot be obtained.

  In this embodiment, since the sacrificial layer removal hole 14 is formed on a substantially flat surface of the surface of the substrate 1, the thickness of the resist 26 is thin at that portion, so that the high-density / high-precision sacrificial layer removal hole 14 is formed. Pattern formation is possible.

Next, as shown in FIG. 26, the sacrifice layer removal hole 14 and the electrode connection hole 16A are opened by etching using the resist 26 formed in the above-described process as a mask. At this time, by performing etching by RIE using CF ₄ + CHF ₃ gas, the laminated film of the oxide film and the nitride film (the diaphragm crack preventing layer 21, the stress adjusting film 20, and the diaphragm side insulating film 18) is continuously etched. And etching can be stopped at the polysilicon layer (sacrificial layer 24).

  After this etching process, the resist 26 is removed to obtain the predetermined sacrificial layer removal hole 14 and the electrode connection hole 16A.

Next, as shown in FIG. 27, after an Al-1% Si film serving as an electrode extraction pad 15A is formed to a thickness of about 0.8 μm, patterning is performed by photolithography and etching processes. Thereafter, the sacrificial layer 24 where the gap 12 is formed is removed by dry etching using SF ₆ plasma or XeF ₂ gas, or wet etching using TMAH to which ammonium persulfate is added.

  Here, when the above materials and etching methods are used, the fixed electrode side insulating layer 22, the diaphragm side insulating layer 18, the diaphragm crack preventing film 21 (all of which are oxide films) exposed to the etchant, and the electrode extraction pad It is possible to remove the sacrificial layer 24 with sufficient selectivity with respect to 15A (Al-1% Si film).

  Then, as shown in FIG. 28, a separately prepared nozzle substrate 2 is attached to the flow path / actuator substrate 1 obtained as described above via an adhesive layer 17. At this time, since the sacrificial layer removal hole 14 is formed in a flat portion on the surface of the substrate 1, the sacrificial layer removal hole 14 can be closed simultaneously with the attachment of the nozzle substrate 2.

  Next, a second embodiment of the droplet discharge head according to the present invention will be described with reference to FIGS. 29 is an explanatory plan view showing the head seen from the nozzle plate side in a transparent state, FIG. 30 is an explanatory plan view showing the pattern of each part in FIG. 29, and FIG. 31 is along the line X3-X3 in FIG. FIG. 32 is a sectional explanatory view taken along line X4-X4 of FIG. 29, FIG. 33 is a sectional explanatory view taken along line Y4-Y4 of FIG. 29, and FIG. 34 is a sectional explanatory view taken along line Y5-Y5 of FIG. FIG. 35 is a cross-sectional explanatory view of the bottom of the pressurized liquid chamber along line X3-X3 in FIG. 29, FIG. 36 is a cross-sectional explanatory view of the bottom of the pressurized liquid chamber along line X4-X4 in FIG. It is sectional explanatory drawing of the pressurized liquid chamber bottom part in alignment with 29 Y4-Y4 lines.

  In the present embodiment, a plurality of gaps (air gaps) 12 and 12 between the diaphragm 11 and the fixed electrode 13 formed on the wall surfaces of two corresponding liquid chamber partition walls 8 of one pressurized liquid chamber 4 are communicated. A communication path 12 b is formed on the bottom surface of the pressurized liquid chamber 4. Other configurations are substantially the same as those in the first embodiment.

  Here, as shown in FIG. 30 (b), the formation positions of the plurality of communication paths 12b are alternated with the communication paths 12a corresponding to the sacrificial layer removal holes 14 in plan view.

  Further, the communication path 12 b is arranged alternately with the diaphragm fixing portion 25 on the bottom surface of the pressurized liquid chamber 4. By forming the diaphragm fixing portion 25 on the bottom surface of the pressurized liquid chamber 4, it is possible to suppress mutual interference between the diaphragms 11 that face each other via the pressurized liquid chamber 4. On the other hand, when the entire surface is communicated with the communication path 12b without forming the diaphragm fixing portion 25 on the bottom surface of the pressurized liquid chamber 4, the two diaphragms 11, 11 facing each other are mutually connected. Interference occurs and stable droplet ejection characteristics cannot be obtained.

  In this way, the formation of the communication passage 12b that communicates the gaps 12 and 12 between the opposing wall surfaces reduces the stagnation of the liquid when the sacrificial layer is removed by the wet process. Is easier to do. As a result, it becomes easy to apply the sacrificial layer removal step by a wet process with high mass productivity, and at the same time, the cost can be reduced.

  Further, when the sacrificial layer is removed by a dry process, the same effect can be obtained when wet cleaning is performed after etching.

  Note that the plan view of FIG. 29 and the cross-sectional views of FIGS. 33 and 34 show different numbers of communication passages 12b, but this is for convenience of illustration and is actually the same. Further, the number of communication paths 12b to be formed is not limited to the number shown in these drawings. For example, when the communication paths 12b are arranged at a pitch of 10 to 50 μm in the pressurized liquid chamber 4 having a liquid chamber length of 1000 μm, 1 100 to 20 nozzles can be formed.

  This embodiment is different from the first embodiment in the pattern of the sacrificial layer 24, but the other configuration is the same as that in the first embodiment, and the manufacturing process is also described in the first embodiment. It is almost the same. Specifically, in the step of forming the fixed electrode side insulating film 22 and the sacrificial layer 24 according to the first embodiment described with reference to FIG. 23, the sacrificial layer 24 remains in the portion that becomes the communication path 12 b. It can be formed by performing a photolithography process using a mask or the like of a sacrificial layer (gap and communication path) pattern shown in FIG.

  Next, a third embodiment of the droplet discharge head according to the present invention will be described with reference to FIGS. 38 is an explanatory plan view showing the head seen from the nozzle plate side in a transparent state, FIG. 30 is an explanatory plan view showing the pattern of each part in FIG. 29, and FIG. 40 is along the line X5-X5 in FIG. 41 is a cross-sectional explanatory view taken along line X6-X6 in FIG. 38, FIG. 42 is a cross-sectional explanatory view taken along line Y7-Y7 in FIG. 38, and FIG. 43 is a cross-sectional explanatory view taken along line Y8-Y8 in FIG. FIG.

  In this embodiment, the diaphragm 11 is individually divided for each nozzle 3 to be individual electrodes, and the electrode (fixed electrode) side facing the diaphragm 11 is a common electrode, and this common electrode is a flow path / actuator substrate. 1 also serves. Other configurations are substantially the same as those in the first embodiment.

  In this case, a silicon substrate having a crystal plane orientation (110) is used as the flow path / actuator substrate 1. However, in order to function as an electrode, the flow path / actuator substrate 1 is manufactured from a low-resistance silicon wafer or reduced in resistance after the flow path is formed. It is preferable to dope impurities for the purpose.

  Next, details of the head configuration of the third embodiment will be described with reference to FIGS. 44 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall taken along line X5-X5 in FIG. 38, FIG. 45 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall taken along line X6-X6 in FIG. 38 is an enlarged cross-sectional view of the upper portion of the liquid chamber interval wall along the line Y9-Y9, FIG. 47 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the nozzle arrangement direction, and FIG. 48 is an additional view along the line Y7-Y7 of FIG. 49 is an enlarged cross-sectional view of the bottom of the pressurized fluid chamber, FIG. 49 is a detailed cross-sectional view of the electrode take-out pad portion for the diaphragm electrode along the line Y9-Y9 in FIG. 38, and FIG. It is.

  Also in the present embodiment, the diaphragm 11 is composed of four layers, the diaphragm side insulating film 18, the diaphragm electrode 19, the stress adjusting film 20, and the diaphragm crack preventing film 21, as in the first embodiment. Each film thickness is adjusted to have a desired rigidity. In addition, the flow path / actuator substrate 1 is fixed separately from the flow path / actuator substrate 1 in order to use the flow path / actuator substrate 1 as an electrode facing the diaphragm 11. The electrode-side insulating film 22 is formed on the flow path / actuator substrate 1 without forming electrodes.

  Thus, by using the flow path / actuator substrate 1 as an electrode (common electrode) opposed to the diaphragm 11, it can be manufactured with fewer steps compared to the head according to the first embodiment. Specifically, the step of forming the substrate insulating film 23 and the fixed electrode 13 is omitted in the example of the first embodiment shown in FIG. 22 described above, and patterning is performed to divide the diaphragm electrode 19 into individual electrodes.

  Further, in the present embodiment, the electrode take-out pad portion 15A for the fixed electrode forms the electrode take-out pad 15A by forming the electrode connection hole 16A penetrating to the flow path / actuator substrate 1.

  Next, a fourth embodiment of the droplet discharge head according to the present invention will be described with reference to FIGS. 51 is an explanatory plan view showing the head seen from the nozzle plate side in a transparent state, FIG. 52 is an explanatory plan view extracting patterns of each part of FIG. 51, and FIG. 53 is along the line X8-X8 in FIG. 54 is a cross-sectional explanatory view taken along line X8-X8 in FIG. 51, FIG. 55 is a cross-sectional explanatory view taken along line Y1-Y10 in FIG. 51, and FIG. 56 is a cross-sectional explanatory view taken along line Y11-Y11 in FIG. 57 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber taken along line X7-X7 in FIG. 51, FIG. 58 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber taken along line X8-X8 in FIG. It is an expanded sectional view of the pressurization liquid room bottom which meets the Y10-Y10 line of 51.

  In the present embodiment, a configuration in which the communication path 12b of the second embodiment described above is provided in the third embodiment described above is applied. As a result, in addition to the operational effects of the third embodiment, it becomes easy to apply the sacrificial layer removal by a wet process with high mass productivity, and the cost can be reduced at the same time, as in the second embodiment.

  Next, a fifth embodiment of the droplet discharge head according to the present invention will be described with reference to FIGS. 60 is an exploded perspective view of the head, FIG. 61 is a plan view showing the head viewed from the nozzle plate side in a transparent state, and FIG. 62 is a plan view showing the extracted patterns of each part of FIG. 63 is a sectional view taken along line X9-X9 in FIG. 61, FIG. 64 is a sectional view taken along line X10-X10 in FIG. 61, FIG. 65 is a sectional view taken along line Y13-Y13 in FIG. 61 is a cross-sectional explanatory view taken along line Y14-Y14 in FIG. 61, FIG. 67 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall taken along line X9-X9 in FIG. 69 is an enlarged cross-sectional view of the upper part of the partition wall, FIG. 69 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall along the line Y3-Y3 in FIG. 61, FIG. FIG. 7 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the line Y13-Y13 in FIG. The cross-sectional view of the pad portion extraction electrode diaphragm electrode, FIG. 73 is a sectional view of the pad portion extraction electrode for the fixed electrode.

  In this droplet discharge head, the pressurized liquid chamber 4 of the flow path / actuator substrate 1 is formed in a V shape in a section in the liquid chamber alignment direction, and the wall surface of the liquid chamber interval wall 8 separating the pressurized liquid chamber 4 is inclined. The surface 8b is used.

  The liquid chamber interval wall 8 having such an inclined surface 8b is formed by digging into the pressurized liquid chamber 4 by anisotropic etching using a crystal plane orientation (100) silicon wafer (silicon substrate). Since the inclined surface appears due to the crystal plane orientation, it can be easily formed. Although other methods can be used as the method for forming the liquid chamber interval wall 8, an inclined surface can be easily and highly accurately formed by combining (100) a single crystal silicon substrate and anisotropic etching. can do.

  As in the third embodiment, the flow path / actuator substrate 1 is a common electrode, and the diaphragm 11 is an individual electrode. Here, the diaphragm 11 corresponding to one wall surface (inclined surface 8 b) of the liquid chamber interval wall 8 fixes the upper and lower portions of the inclined surface 8 a as the diaphragm fixing portions 25 and 25. That is, the area of the deformable region 11 a of the diaphragm 11 is smaller than the area of the inclined surface of the liquid chamber interval wall 8, and the short side length of the deformable region 11 a of the diaphragm 11 is that of the inclined surface of the liquid chamber interval wall 8. It is shorter than the length, or the deformable region 11 a of the diaphragm 11 is configured to face the inclined surface 8 b in the inclined surface 8 b of the liquid chamber interval wall 8. Other configurations and details of each part are the same as those of the third embodiment described above.

  Thus, in this head, the vibration plate 11 is fixed by forming the vibration plate fixing portions 25, 25 on the upper portion (the upper portion of the liquid chamber) and the lower portion (the bottom portion of the liquid chamber) of the inclined surface 8 a of the liquid chamber interval wall 8. Since it is a structure, the length (short side length) of the diaphragm 11 is determined by the angle of the inclined surface 8b of the liquid chamber interval wall 8 and the pattern accuracy in the sacrificial layer photolithography etching, and is highly accurate. A diaphragm (deformable region) can be formed and a stable operation can be obtained.

  That is, in the case of forming by anisotropic etching, as described above, the angle of the inclined surface 8b is determined by the crystal plane orientation, so that it can be formed with reduced variation. The pattern accuracy by photolithography and etching varies depending on the equipment used, resist type, process conditions, etc., but should be within ± 1μm (diaphragm length. ± 0.6μm within the length projected on the plane). Is fully possible.

  On the other hand, for example, as shown in FIG. 74, the diaphragm fixing portion 25 is provided only at the lower part of the inclined surface 8 b of the liquid chamber interval wall 8, that is, at the bottom side of the pressurized liquid chamber 4. The diaphragm fixing portion 25 may not be provided on the upper portion of the inclined surface 8b of FIG. 8, but the variation in the diaphragm length (short side length) in this case is also present on the upper side of the pressurized liquid chamber 4. It becomes larger than the case where the diaphragm fixing | fixed part 25 is provided.

  This point will be described with reference to FIGS. 76 is an explanatory view of the vibration plate length variation when the diaphragm fixing portions 25, 25 are provided on the upper and lower portions of the inclined surface 8b of the liquid chamber interval wall 8. FIG. It is explanatory drawing of the diaphragm length variation at the time of setting it as the structure which provides the diaphragm fixing | fixed part 25 only in the lower part of the inclined surface 8b.

  First, in the configuration in which the diaphragm fixing portions are provided in the upper part and the lower part of the liquid chamber shown in FIG. 76, a recess is formed by anisotropic etching using a silicon substrate in the flow path / actuator substrate 1 to form a liquid chamber interval wall. When the inclined surface 8b of FIG. 8 is formed, a variation W1 of (mask variation in anisotropic etching + side etching variation in anisotropic etching) occurs. On the other hand, since sacrificial layer patterning for leaving a sacrificial layer for forming the gap 12 is performed using a mask, variations W2 and W2 due to mask alignment occur at the liquid chamber upper fixed end and the liquid chamber lower fixed end.

  In this case, the variations W2 and W2 of the mask alignment simultaneously form the liquid chamber upper fixed end and the liquid chamber lower fixed end with one mask, so that the alignment deviation occurs in the same direction, and the diaphragm length (short) The side length) will not change. Since exposure for sacrificial layer patterning is performed from above in FIG. 76, the vibration plate length (short side length) does not change even if the variation W1 occurs on the inclined surface 8b by anisotropic etching. . For example, the diaphragm length b1 when the inclined surface 8b is at the position shown by the solid line and the diaphragm length b2 when the inclined surface 8b is at the position shown by the phantom line are the same. In other words, since the diaphragm length (short side length) b is defined by the liquid chamber upper fixed end and the liquid chamber lower fixed end, accuracy can be obtained.

  On the other hand, in the configuration in which the diaphragm fixing portion is provided only at the lower part of the liquid chamber shown in FIG. 77, if the variation W2 in the mask alignment for sacrificial layer patterning occurs, the variation W2 is obtained even if the position of the inclined surface 8b is constant. The diaphragm length changes by a considerable amount, and even if the mask alignment variation W2 is changed, it also varies depending on the anisotropic etching mask size and the side etch variation W1 when the inclined surface 8b is formed. . For example, a difference of (b12−b11) occurs between the diaphragm length b11 when the inclined surface 8b is at the position shown in the solid line and the diaphragm length b12 when the inclined surface 8b is at the position shown in the phantom line. As a result, accuracy cannot be obtained.

  The value of the vibration plate length variation when the vibration plate fixing portion 25 is provided only on the liquid chamber bottom side is (the vibration plate fixing portion 25 size (fixed portion end position) variation under the pressurized liquid chamber 4 + Alignment variation + anisotropic etch mask variation + anisotropic etch side etch variation).

  On the other hand, as shown in FIG. 75, when the diaphragm fixing portion 25 is not formed in the lower part of the pressurized liquid chamber 4, the two inclined surfaces 8b and 8b facing each other through the pressurized liquid chamber 4 of the diaphragm 11 are provided. The areas facing each other interfere with each other, and stable operating characteristics cannot be obtained.

  In this embodiment, the diaphragm electrode 19 is individually provided for each nozzle 3, the diaphragm 11 is an individual electrode, and the flow path / actuator substrate 1 is a common electrode. However, the diaphragm electrode 19 is a common electrode. The individual electrodes may be provided on the flow path / actuator substrate 1 side.

  Next, a sixth embodiment of the droplet discharge head according to the present invention will be described with reference to FIGS. 78 is an explanatory plan view showing the head viewed from the nozzle plate side in a transparent state, FIG. 79 is an explanatory plan view extracting patterns of each part of FIG. 78, and FIG. 80 is taken along line X11-X11 in FIG. 81 is a cross-sectional explanatory view taken along line X12-X12 in FIG. 78, FIG. 82 is a cross-sectional explanatory view taken along line Y16-Y16 in FIG. 78, and FIG. 83 is a cross-sectional explanatory view taken along line Y17-Y17 in FIG. 84 and FIG. 84 are enlarged sectional views of the bottom of the pressurized liquid chamber along line X11-X11 in FIG. 78, FIG. 85 is an enlarged sectional view of the bottom of the pressurized liquid chamber along line X12-X12 in FIG. It is an expanded sectional view of the pressurization liquid room bottom which meets the Y16-Y16 line of 78.

  In the present embodiment, as in the second and fourth embodiments described above, the gap 12 formed on the inclined surfaces 8b, 8b of the two liquid chamber spacing walls 8 facing each other via the pressurized liquid chamber 4 is The pressurized liquid chamber 4 is communicated via a plurality of communication passages 12 b formed on the bottom surface. Other configurations are substantially the same as those of the fifth embodiment.

  By adopting such a configuration, in addition to the effects of the fifth embodiment, the sacrificial layer removal by the wet process with high mass productivity can be applied as described in the second and fourth embodiments. At the same time, and cost can be reduced.

Next, a seventh embodiment of the droplet discharge head according to the present invention will be described with reference to FIG. FIG. 87 is an explanatory perspective view of the head in an exploded state.
This droplet discharge head is configured by laminating a flow path / actuator substrate 1 and a nozzle substrate 2. The flow path / actuator substrate 1 is previously formed with recesses that serve as the pressurized liquid chamber 4 and the common liquid chamber 6, and the nozzle substrate 2 has liquid in the nozzle hole 3, the fluid resistance portion 5, and the common liquid chamber 6. A liquid supply port 7 for supplying the liquid is formed.

  By joining the flow path / actuator substrate 1 and the nozzle substrate 2, liquid (ink) is supplied to the pressurized liquid chamber 4 and the pressurized liquid chamber 4 through which the nozzle holes 3 for discharging droplets formed on the nozzle substrate 2 communicate. The fluid resistance portion 5 and the common liquid chamber 6 are formed. Each pressurized liquid chamber 4 is partitioned by a liquid chamber interval wall 8.

Next, an eighth embodiment of the droplet discharge head according to the present invention will be described with reference to FIG. FIG. 88 is an explanatory perspective view of the head in an exploded state.
This droplet discharge head is formed by laminating a flow path / actuator substrate 1 and a top plate 42. In the flow path / actuator substrate 1, recesses are formed in advance such as a nozzle 43, a pressurized liquid chamber 4, a fluid resistance portion 5, a common liquid chamber 6, and the like. A liquid supply port 7 for supplying is formed.

  By joining the flow path / actuator substrate 1 and the top plate 2, the pressurized liquid chamber 4 communicated with the nozzle 43, the fluid resistance section 5 for supplying liquid (ink) to the pressurized liquid chamber 4, and the common liquid chamber 6 is formed. Each pressurized liquid chamber 4 is partitioned by a liquid chamber interval wall 8.

  When this embodiment is compared with the first embodiment, the droplet discharge of the droplet discharge head of the first embodiment is discharged from the nozzle hole 3 formed in the nozzle substrate 2 in a direction substantially perpendicular to the nozzle plate surface. In contrast to the so-called side shooter (face shooter) configuration, the droplet discharge of the droplet discharge head according to the present embodiment is joined by the nozzle 43 formed on the flow path / actuator substrate 1. It is a so-called edge shooter type structure that discharges in a substantially horizontal direction with respect to the substrate surface. FIG. 88 is a conceptual diagram of this embodiment, and details of the nozzle 3 are not shown.

Next, a ninth embodiment of the droplet discharge head according to the present invention will be described with reference to FIG. FIG. 89 is an explanatory perspective view of the head in an exploded state.
In the present embodiment, like the fifth embodiment, the liquid chamber interval wall 8 has an inclined surface 8b, and other configurations are substantially the same as those of the ninth embodiment.

  As described above, according to the electrostatic actuator according to the present invention, the diaphragm is provided on the wall surface of the liquid chamber interval wall, and the gap between the diaphragm and the electrode is formed by the sacrificial layer etching process. A diaphragm and a gap can be formed, and highly accurate droplet discharge can be performed.

  Further, according to the electrostatic actuator according to the present invention, the sacrificial layer removal hole is formed in a portion corresponding to the surface of the liquid chamber interval wall that does not form the liquid chamber wall surface. It becomes easy. Further, since the sacrificial layer removal holes can be formed with high density and high accuracy, the sacrificial layer can be removed with high efficiency and low variation.

  According to the electrostatic actuator according to the present invention, since at least one surface forming the wall surface of the liquid chamber interval wall is an inclined surface, the accuracy of the length of the diaphragm is improved. In addition, variations in droplet discharge characteristics can be reduced.

  Furthermore, according to the electrostatic actuator according to the present invention, the diaphragm, the gap (gap) corresponding to the diaphragm, the sacrificial layer removal hole, and the diaphragm fixing portion are provided on the opposing wall surfaces of the liquid chamber, Since the deformable region is formed smaller than the wall surface region of the liquid chamber interval wall and the communication path that connects the gaps corresponding to the diaphragms to each other is provided, the mutual interference of the plurality of diaphragms can be suppressed. When the sacrificial layer is removed by a wet process due to the effect of the communication path, it becomes easy to perform the water washing and drying process after etching, so that the sacrificial layer can be easily removed by the wet process with high productivity and the cost is reduced. be able to.

  Further, according to the droplet discharge head according to the present invention, since the electrostatic actuator according to the present invention is provided, stable droplet discharge characteristics can be obtained, and the head member can be reduced in size and cost. be able to.

  In all the above embodiments, the configuration of the diaphragm 11 shows a four-layer structure made of an oxide film, polysilicon, nitride film, and oxide film, but the number of layers and combinations thereof are limited to this. It is not a thing, but it can also be set as the other combination from which the number of lamination | stacking and material differ.

  Next, an example of the mechanism of an ink jet recording apparatus that is an image forming apparatus according to the present invention on which an ink jet head that is a liquid droplet ejection head according to the present invention is mounted will be described with reference to FIGS. 91 and 92. FIG. 91 is a perspective explanatory view of the recording apparatus, and FIG. 92 is a side explanatory view of a mechanism portion of the recording apparatus.

  The ink jet recording apparatus includes a carriage that can move in the main scanning direction inside the recording apparatus main body 111, a recording head that includes the droplet discharge head according to the present invention mounted on the carriage, an ink cartridge that supplies ink to the recording head, and the like. The printing mechanism 112 and the like configured are accommodated, and a paper feed cassette (or a paper feed tray) 114 on which a large number of sheets 113 can be stacked from the front side is detachably attached to the lower part of the apparatus main body 111. In addition, the manual tray 115 for manually feeding the paper 113 can be opened, the paper 113 fed from the paper feed cassette 114 or the manual tray 115 is taken in, and the printing mechanism unit 112 is loaded. After recording a required image, the paper is discharged to a paper discharge tray 116 mounted on the rear side.

  The printing mechanism 112 holds a carriage 123 slidably in the main scanning direction by a main guide rod 121 and a sub guide rod 122 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), black (Bk) each head is composed of an ink jet head that is a liquid droplet ejection head according to the present invention for ejecting ink droplets of each color, and a plurality of ink ejection openings are mainly used. They are arranged in a direction crossing the scanning direction and mounted with the ink droplet ejection direction facing downward. Also, each ink cartridge 125 for supplying each color ink to the head 124 is replaceably mounted on the carriage 123. The ink cartridge according to the present invention can be mounted.

  The ink cartridge 125 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the inkjet head below, and a porous body filled with ink inside, and the capillary force of the porous body Thus, the ink supplied to the inkjet head is maintained at a slight negative pressure.

  Further, although the heads 124 of the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used.

  Here, the carriage 123 is slidably fitted to the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 122 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a driving pulley 128 and a driven pulley 129 that are rotationally driven by a main scanning motor 127. The carriage 123 is reciprocally driven by forward and reverse rotations of the main scanning motor 127.

  On the other hand, in order to convey the sheet 113 set in the sheet cassette 114 to the lower side of the head 124, the sheet 113 is guided from the sheet feeding cassette 114 to the sheet feeding roller 131 and the friction pad 132. A guide member 133, a transport roller 134 that reverses and transports the fed paper 113, a transport roller 135 that is pressed against the peripheral surface of the transport roller 134, and a tip that defines the feed angle of the paper 113 from the transport roller 134 A roller 136 is provided. The transport roller 134 is rotationally driven by a sub-scanning motor 137 through a gear train.

  A printing receiving member 139 is provided as a paper guide member that guides the paper 113 fed from the transport roller 134 on the lower side of the recording head 124 corresponding to the movement range of the carriage 123 in the main scanning direction. On the downstream side of the printing receiving member 139 in the paper conveyance direction, a conveyance roller 141 and a spur 142 that are rotationally driven to send the paper 113 in the paper discharge direction are provided, and paper discharge that further feeds the paper 113 to the paper discharge tray 116. A roller 143 and a spur 144, and guide members 145 and 146 forming a paper discharge path are disposed.

  At the time of recording, the recording head 124 is driven according to the image signal while moving the carriage 123, thereby ejecting ink onto the stopped sheet 113 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 113 reaches the recording area, the recording operation is terminated and the sheet 113 is discharged.

  A recovery device 147 for recovering defective ejection of the head 124 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 123. The recovery device 147 includes a cap unit, a suction unit, and a cleaning unit. The carriage 123 is moved to the recovery device 147 side during printing standby, and the head 124 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the head 124 is sealed by the capping unit, and bubbles and the like are sucked out from the discharge port by the suction unit through the tube. Is removed by the cleaning means to recover the ejection failure. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  According to this ink jet recording apparatus, since the ink jet head which is the liquid droplet ejection head according to the present invention is provided, stable liquid droplet ejection characteristics with low power consumption and little variation can be obtained, and high quality images can be obtained. A forming apparatus can be realized.

Next, an example of a micropump according to the present invention that includes an electrostatic actuator according to the present invention will be described with reference to FIG.
The micropump includes an actuator substrate 201 that constitutes an electrostatic actuator according to the present invention, and a top plate 202 that forms a flow path 203 for flowing a fluid between the actuator substrate 201. As described in the fifth embodiment of the droplet discharge head, a liquid chamber 204 (liquid chamber interval wall 208) having an inclined surface having a substantially V-shaped cross section is formed on the actuator substrate 201. The actuator substrate 201 itself Is used as a common electrode, and a diaphragm 211 is provided on the inclined surface of each liquid chamber interval wall 208. Note that the diaphragm 211 is fixed to the substrate 201 on the upper and lower sides of the inclined surface as in the fifth embodiment.

  The operation principle of the micropump will be described. As in the case of the liquid droplet ejection head described above, the pulsed potential is selectively applied to the diaphragm 211 so that the diaphragm 211 and the actuator substrate 201 which is a fixed electrode are connected. Since an electrostatic attraction force is generated between them, the diaphragm 211 is deformed. Here, by sequentially driving the diaphragm 211 corresponding to one liquid chamber 204 from the right side in the drawing, the fluid in the channel 201 flows in the direction of the arrow, and the fluid can be transported.

  In this case, by providing the electrostatic actuator according to the present invention, it is possible to obtain a small and low-power-consumption micropump capable of stable liquid transportation with little variation in characteristics. In addition, although the example which has two or more diaphragms (deformable area | regions) was shown here, one deformable area | region may be sufficient. In order to increase transport efficiency, one or more valves such as a check valve may be provided between the liquid chambers.

FIG. 2 is an exploded perspective view of the first embodiment of the droplet discharge head according to the present invention. FIG. 3 is an explanatory plan view showing the head in a transmissive state when viewed from the nozzle plate side. FIG. 3 is an explanatory plan view in which patterns of respective parts in FIG. 2 are extracted. FIG. 3 is a cross-sectional explanatory view taken along line X1-X1 in FIG. FIG. 3 is a cross-sectional explanatory view taken along line X2-X2 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line Y1-Y1 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line Y2-Y2 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line Y3-Y3 in FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part which follows the X1-X1 line | wire of FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part which follows the X2-X2 line | wire of FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part along the Y3-Y3 line | wire of FIG. It is an expanded sectional view of the pressurizing liquid chamber bottom along the arrangement direction of the nozzles. FIG. 3 is an enlarged cross-sectional view of the bottom of a pressurized liquid chamber along the line Y1-Y1 in FIG. It is sectional explanatory drawing of the electrode extraction pad part for fixed electrodes. It is a cross-sectional explanatory view of the electrode take-out pad portion for the diaphragm electrode. It is an expanded sectional view of the liquid chamber space | interval wall upper part which follows the X1-X1 line | wire of FIG. 2 which shows the other example of the same embodiment. It is an expanded sectional view of the liquid chamber space | interval wall upper part corresponding to the cross section which follows the X2-X2 line of FIG. FIG. 3 is an enlarged cross-sectional view of an upper portion of the liquid chamber interval wall corresponding to a cross section along line Y3-Y3 in FIG. FIG. 10 is a cross-sectional explanatory view of the bottom of the pressurized liquid chamber along the nozzle arrangement direction showing still another example of the embodiment. FIG. 3 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber corresponding to a cross section along line Y1-Y1 in FIG. FIG. 5 is a cross-sectional explanatory diagram for explaining a manufacturing process of the droplet discharge head according to the first embodiment. FIG. 22 is a cross-sectional explanatory view illustrating the process following FIG. 21. FIG. 23 is a cross-sectional explanatory view illustrating the process following FIG. 22. FIG. 24 is an explanatory cross-sectional view illustrating a step that similarly follows FIG. 23. FIG. 25 is a cross-sectional explanatory view illustrating the process following FIG. 24. FIG. 26 is a cross-sectional explanatory view illustrating the process following FIG. 25. FIG. 27 is an explanatory cross-sectional view illustrating a process following FIG. 26. FIG. 28 is a cross-sectional explanatory view illustrating the process following FIG. 27. It is a plane explanatory view showing the second embodiment of the droplet discharge head according to the present invention in a transmissive state as viewed from the nozzle plate side. It is plane explanatory drawing which extracted the pattern of each part of FIG. FIG. 30 is an explanatory cross-sectional view taken along line X3-X3 of FIG. FIG. 30 is an explanatory cross-sectional view taken along line X4-X4 of FIG. FIG. 30 is an explanatory cross-sectional view taken along line Y4-Y4 of FIG. 29. FIG. 30 is an explanatory cross-sectional view taken along line Y5-Y5 of FIG. FIG. 30 is an explanatory cross-sectional view of the bottom of the pressurized liquid chamber along the line X3-X3 in FIG. 29. FIG. 30 is a cross-sectional explanatory view of the bottom of the pressurized liquid chamber along the line X4-X4 of FIG. 29. FIG. 30 is an explanatory cross-sectional view of the bottom of the pressurized liquid chamber along the line Y4-Y4 in FIG. 29. It is a plane explanatory view shown in the permeation | transmission state seen from the nozzle plate side of 3rd Embodiment of the droplet discharge head concerning this invention. It is plane explanatory drawing which extracted the pattern of each part of FIG. It is sectional explanatory drawing which follows the X5-X5 line | wire of FIG. It is sectional explanatory drawing which follows the X6-X6 line | wire of FIG. FIG. 39 is an explanatory cross-sectional view taken along line Y7-Y7 of FIG. FIG. 39 is an explanatory cross-sectional view taken along line Y8-Y8 of FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part along the X5-X5 line | wire of FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part along the X6-X6 line | wire of FIG. It is an expanded sectional view of the liquid chamber space | interval wall upper part along the Y9-Y9 line | wire of FIG. It is an expanded sectional view of the pressurizing liquid chamber bottom along the arrangement direction of the nozzles. FIG. 39 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the line Y7-Y7 in FIG. It is a cross-sectional explanatory view of the electrode take-out pad portion for the diaphragm electrode. It is sectional explanatory drawing of the electrode extraction pad part for fixed electrodes. It is a plane explanatory view shown in the permeation | transmission state seen from the nozzle plate side of 4th Embodiment of the droplet discharge head concerning this invention. FIG. 52 is an explanatory plan view showing a pattern extracted from each part of FIG. 51. FIG. 52 is a cross-sectional explanatory view taken along line X7-X7 in FIG. 51. FIG. 52 is a cross-sectional explanatory view taken along line X8-X8 in FIG. 51. FIG. 52 is an explanatory cross-sectional view taken along line Y10-Y10 of FIG. 51. FIG. 52 is an explanatory cross-sectional view taken along line Y11-Y11 of FIG. 51. FIG. 52 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the line X7-X7 in FIG. 51. FIG. 52 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the line X8-X8 in FIG. 51. FIG. 52 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the line Y10-Y10 in FIG. 51. FIG. 9 is a perspective explanatory view of a fifth embodiment of a droplet discharge head according to the present invention. It is plane explanatory drawing shown in the permeation | transmission state seen from the nozzle plate side of the head. FIG. 62 is an explanatory plan view of the pattern of each part in FIG. 61 extracted. FIG. 62 is an explanatory cross-sectional view taken along line X9-X9 of FIG. 61. FIG. 62 is a cross-sectional explanatory view taken along line X10-X10 in FIG. 61. FIG. 62 is an explanatory cross-sectional view taken along line Y13-Y13 of FIG. 61. FIG. 62 is an explanatory cross-sectional view taken along line Y14-Y14 of FIG. 61. FIG. 62 is an enlarged cross-sectional view of an upper part of the liquid chamber interval wall taken along line X9-X9 in FIG. 61. FIG. 62 is an enlarged cross-sectional view of the upper part of the liquid chamber interval wall taken along line X10-X10 in FIG. 61. FIG. 62 is an enlarged cross-sectional view of an upper portion of a liquid chamber interval wall along the line Y15-Y15 in FIG. 61. FIG. 70 is an enlarged cross-sectional view of the bottom of the pressurized liquid chamber along the nozzle arrangement direction. It is an expanded sectional view of the pressurization liquid room bottom which meets the Y13-Y13 line of FIG. It is a detailed explanatory view of an electrode extraction pad portion for a diaphragm electrode. It is detailed explanatory drawing of the electrode extraction pad part for fixed electrodes. FIG. 62 is a cross-sectional explanatory diagram of another form corresponding to the cross section taken along the line X9-X9 of FIG. 61 for explaining the operation of the same embodiment; FIG. 69 is a cross-sectional explanatory view of yet another embodiment corresponding to a cross section taken along line X9-X9 of FIG. It is explanatory drawing with which it uses for operation | movement description of the same embodiment. FIG. 75 is an explanatory diagram for describing an operation of the embodiment of FIG. 74. It is plane explanatory drawing shown in the permeation | transmission state seen from the nozzle plate side of 6th Embodiment of the droplet discharge head concerning this invention. FIG. 79 is an explanatory plan view showing a pattern extracted from each part of FIG. 78; FIG. 79 is an explanatory sectional view taken along line X11-X11 in FIG. 78. FIG. 79 is an explanatory sectional view taken along line X12-X12 of FIG. 78. FIG. 79 is an explanatory sectional view taken along the line Y16-Y16 in FIG. 78. FIG. 79 is an explanatory sectional view taken along the line Y17-Y17 in FIG. 78. FIG. 79 is an enlarged cross-sectional view of the bottom of a pressurized liquid chamber along line X11-X11 in FIG. 78. FIG. 79 is an enlarged cross-sectional view of the bottom of a pressurized liquid chamber along line X12-X12 in FIG. 78. FIG. 79 is an enlarged cross-sectional view of the bottom of a pressurized liquid chamber along the line Y16-Y16 in FIG. 78. It is a disassembled perspective explanatory drawing of 7th Embodiment of the droplet discharge head which concerns on this invention. It is a disassembled perspective explanatory drawing of 8th Embodiment of the droplet discharge head which concerns on this invention. It is a disassembled perspective explanatory drawing of 9th Embodiment of the droplet discharge head which concerns on this invention. 1 is a perspective explanatory view illustrating an example of an image forming apparatus according to the present invention. FIG. 3 is a side explanatory view of a mechanism unit of the image forming apparatus. It is a typical section bright view explaining an example of a micro pump concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flow path / actuator substrate 2 ... Nozzle substrate 3 ... Nozzle hole 4 ... Pressurized liquid chamber 5 ... Fluid resistance part 6 ... Common liquid chamber 7 ... Liquid supply port 8 ... Liquid chamber space | interval wall part 10 ... Actuator element 11 ... Vibration Plate 24 ... Sacrificial layer 12 ... Gaps
DESCRIPTION OF SYMBOLS 12b ... Communication path 13 ... Fixed electrode 14 ... Sacrificial layer removal hole 15 ... Electrode extraction pad 16 ... Electrode connection hole 17 ... Adhesive layer 18 ... Diaphragm side insulating layer 19 ... Diaphragm electrode 20 ... Stress adjustment layer 21 ... Diaphragm Crack prevention film 22 ... Fixed electrode side insulating layer 23 ... Insulating film 24 ... Sacrificial layer 25 ... Diaphragm fixing part

Claims (10)

  An electrostatic actuator comprising a diaphragm and an electrode opposed to the diaphragm through a gap, wherein the diaphragm is deformed by an electrostatic force, the diaphragm is provided on a wall surface of a liquid chamber interval wall, and the diaphragm and the electrode An electrostatic actuator characterized in that the gap is formed by a sacrificial layer etching process.   2. The electrostatic actuator according to claim 1, wherein a sacrificial layer removal hole for removing the sacrificial layer is formed in a portion corresponding to a surface of the liquid chamber interval wall that does not form a liquid chamber wall surface. Electrostatic actuator that performs.   3. The electrostatic actuator according to claim 1, wherein at least one surface forming a wall surface of the liquid chamber of the liquid chamber interval wall is an inclined surface.   4. The electrostatic actuator according to claim 1, wherein a diaphragm is provided on each of the opposing wall surfaces of the liquid chamber.   5. The electrostatic actuator according to claim 1, wherein a deformable region of the diaphragm is smaller than a wall surface region of the liquid chamber interval wall.   5. The electrostatic actuator according to claim 4, further comprising a communication path that connects gaps corresponding to the respective diaphragms to each other.   The electrostatic actuator according to claim 6, wherein a plurality of the communication paths are provided.   8. A droplet discharge head including an electrostatic actuator for discharging droplets from a nozzle, wherein the electrostatic actuator is the electrostatic actuator according to any one of claims 1 to 7. Droplet discharge head.   9. An image forming apparatus comprising a droplet discharge head according to claim 8, wherein the image forming apparatus includes a droplet discharge head for discharging a droplet to form an image on a recording medium.   A micropump for transporting a liquid by deformation of a diaphragm, comprising the electrostatic actuator according to any one of claims 1 to 7.

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