JP2003341055A - Droplet discharge head and ink jet recording apparatus - Google Patents

Abstract

(57) [Summary] [Problem] It is not possible to obtain a high drop ejection efficiency at low cost. SOLUTION: A second substrate 2 facing a diaphragm 10 is joined to a first substrate 1 via a spacer member 12 to form a space 13 between the first substrate 1 and the second substrate 2. Space 13
Inside, two first electrodes 14 having a substantially L-shaped cross section are provided on the diaphragm 10 side, and the first electrodes 1 are provided on the second substrate 2 side.
The second electrode 1 opposing the first and fourth electrodes 4 and 14 via the gap 17.
The first electrode 14 and the second electrode 15 generate an electrostatic attraction in a direction substantially parallel to the diaphragm 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head and an ink jet recording apparatus.

[0002]

2. Description of the Related Art An ink jet head, which is a liquid drop ejection head used in an ink jet recording apparatus used as an image recording apparatus such as a printer, a facsimile, a copying machine or an image forming apparatus, has a single or a plurality of nozzle holes for ejecting ink droplets. And a discharge chamber (also referred to as a pressurizing chamber, an ink chamber, a liquid chamber, a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) communicating with the nozzle hole, and a pressure for pressurizing the ink in the discharge chamber. And a pressure generating unit for generating the pressure, and pressurizing the ink in the discharge chamber with the pressure generated by the pressure generating unit to discharge the ink droplet from the nozzle hole.

As the droplet discharge head, for example, a droplet discharge head for discharging a liquid resist as droplets, DN
There is also a droplet discharge head that discharges the sample A as droplets, but in the following, an inkjet head will be mainly described. Further, the microactuator forming the actuator portion of the droplet discharge head is, for example, an optical device such as a micropump or a micro light modulation device, a micro switch (micro relay), an actuator (optical switch) of a multi-optical lens, a micro flow meter, It can also be applied to pressure sensors and the like.

By the way, as a droplet discharge head, an electromechanical conversion element such as a piezoelectric element is used as a pressure generating means to deform and displace a vibrating plate forming the wall surface of the discharge chamber to discharge ink droplets. Type, a thermal type that uses an electrothermal conversion element such as a heating resistor arranged in the discharge chamber to generate bubbles by ink film boiling and discharges ink droplets, vibration that forms the wall surface of the discharge chamber There is an electrostatic type in which a plate is deformed by electrostatic force to eject ink droplets.

In recent years, a lead-free bubble type and an electrostatic type have been attracting attention due to environmental problems. In addition to lead-free, a plurality of electrostatic types have been proposed which have little influence on the environment from the viewpoint of low power consumption. ing.

In this electrostatic ink jet head, for example, as described in Japanese Patent Laid-Open No. 6-71882, a pair of electrodes is provided through an air gap, and one electrode is a vibrating plate. An ink chamber filled with ink is formed on the side opposite to the electrodes facing the vibrating plate, and an electrostatic attractive force acts between the electrodes by applying a voltage between the electrodes (between the vibrating plate and the electrodes). (Vibration plate)
When the voltage is removed and the voltage is removed, the vibrating plate returns to its original state due to the elastic force, and there is a method in which the force is used to eject ink droplets.

Further, as described in Japanese Patent Application Laid-Open No. 2000-15805, a protrusion is provided on the surface of the vibration plate made of a silicon substrate, an electrode is formed on the protrusion, and a voltage is applied to the electrode. In some cases, the vibrating plate is deformed by an electrostatic force acting between the protrusions to eject ink droplets.

Further, as described in Japanese Patent Application Laid-Open No. 2001-47624, a vibrating plate is provided on one of the electrode pairs which are formed in a comb-like shape and are nested in each other, and a voltage is applied to the electrode pair. Generates electrostatic attraction between the comb teeth,
There is also a type in which the diaphragm is deformed by the displacement of the electrodes and the ink is ejected by the elastic force of the diaphragm when the voltage is cut off.

[0009]

However, in the above-described head using the diaphragm and the electrode (electrode pair) facing the diaphragm, the displacement of the diaphragm cannot be increased and a large excluded volume is obtained. It is difficult to eject large ink droplets. Further, since the return spring force of the vibration plate is used as the pressure generating means for ejecting the ink droplets, the pressure controllability for ejecting the liquid is not good, and it is difficult to control the droplet amount with high accuracy, and high image quality is achieved. In addition, it is difficult for the diaphragm to eject ink, and the driving voltage for attracting such a diaphragm having high rigidity by electrostatic force becomes high. Alternatively, to reduce the voltage, the air gap between the electrodes must be made extremely small, and such a minute gap can be accurately
It is very difficult to form with less variation.

Further, in a head having a vibrating plate on one side of electrode pairs formed in a comb shape and nested in each other,
Since the comb-teeth-shaped electrode is used, the displacement amount can be increased, but the generated force is very small, and if an attempt is made to generate the generated force enough to eject ink droplets, the voltage will be extremely high. There is a problem. Moreover, since the structure is complicated, it is difficult to manufacture, and there is a problem that the cost becomes high.

Moreover, it is necessary to form a protrusion on the diaphragm and attach an electrode to this protrusion, and it is difficult to attach an electrode to the surface of such a three-dimensional fine structure, and the electrode is not formed well. There is a problem that a part is formed or variation occurs, stable manufacturing cannot be performed, and yield is low.

Further, in order to reduce the voltage, the distance between the protrusions must be narrowed, but it is difficult to form an electrode in such a narrow space, and the electrode is formed between the narrow protrusions. Then, a defect such as a short circuit may occur. Further, it is impossible to form an electrode on the protrusion by a general method because the photolithography process in a three-dimensional structure is difficult in resist coating, exposure, etc. Therefore, using a special device, There is a problem that the manufacturing process becomes long and the cost becomes high.

The present invention has been made in view of the above problems, and is provided with a droplet ejection head that is low in cost, high in droplet ejection efficiency, and capable of obtaining stable droplet ejection characteristics. It is an object of the present invention to provide an inkjet recording device capable of high quality recording.

[0014]

In order to solve the above problems, a droplet discharge head according to the present invention is provided with a first electrode on a vibrating plate and a second electrode on a fixed portion facing the vibrating plate. The diaphragm is deformed by providing an electrostatic force in a direction substantially parallel to the diaphragm between the first electrode and the second electrode.

Here, it is preferable that the first electrode has a long portion in a direction substantially perpendicular to the diaphragm surface. Also,
The first electrode preferably has a substantially L-shaped cross section, and in this case, the first electrode having an L-shaped cross section has a length substantially parallel to the vibration plate rather than a length of a portion substantially perpendicular to the vibration plate surface. It is preferable that the length of the portion is long.

Furthermore, the second electrode can be arranged inside or outside the first electrode. The Young's modulus of the diaphragm is preferably 1E4MP or less, and the diaphragm is preferably made of an insulating organic polymer material.
Furthermore, it is preferable that the fulcrum portion of the second electrode is not fixed.

In the droplet discharge head according to the present invention, the vibrating plate is provided with the first electrode, the fixed portion facing the vibrating plate is provided with the second electrode, and the first electrode and the second electrode are provided. A piezoelectric material is sealed in between, and the diaphragm is deformed by the inverse piezoelectric effect of the piezoelectric material.

The ink jet recording apparatus according to the present invention is
The inkjet head for ejecting ink droplets is the droplet ejection head according to the present invention.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an inkjet head according to a first embodiment of a droplet discharge head of the present invention, which is a partial cross-sectional view. FIG. 2 is a cross-sectional explanatory view of the head taken along the lateral direction of the diaphragm, and FIG.

This ink jet head is of a side shooter type in which ink droplets are ejected from nozzle holes provided on the surface of the substrate, and three first, second and third substrates 1, 2 and 3 are stacked. It has a laminated structure that is joined by
By bonding the first substrate 1 and the third substrate 3 to each other, the discharge chambers 6 communicating with the plurality of nozzle holes 4 for discharging ink droplets, and the common ink supply to each discharge chamber 6 via the fluid resistance portion 7 A liquid chamber (common ink chamber) 8 and the like are formed. It is also possible to use an edge shooter type in which ink droplets are ejected from nozzle holes provided at the end of the substrate.

The intermediate first substrate 1 is made of a silicon substrate, and has a recess for forming the discharge chamber 6 and each discharge chamber 6.
A corrosive-resistant film having a recess for forming a common liquid chamber 8 for supplying ink to the ink, and having a corrosive resistance to ink made of an organic resin film such as polyimide on the wall surface of the ejection chamber 6. 21 is formed.

A vibration plate 10 for forming one wall surface of the discharge chamber 6 is provided on the bottom surface of the first substrate 1, and insulating films 11a such as an oxide film 11a and 1a are formed on both surfaces of the vibration plate 10.
1b are formed respectively. The diaphragm 10 is preferably formed of a material having a low Young's modulus, particularly a material having a Young's modulus of 1E4MP or less. For example, an insulating organic polymer resin such as polyimide or PBO film can be used.
In addition to the insulating material, a conductive resin such as polypyrrole or polyaniline can be used.

Further, the first substrate 1 is joined to the second substrate 2 which is a facing member facing the diaphragm 10 via the partition wall (spacer member) 12 and forms a fixed portion. A space 13 is formed between the second substrate 2 and the second substrate 2. Then, in this space 13, two diaphragm-shaped first electrodes 14 and 14 having a substantially L-shaped cross section are provided on the diaphragm 10 side, and a gap 17 is formed on the first substrate 14 and 14 on the second substrate 2 side. A second electrode 15 facing each other is provided, and the first electrode 14 and the second electrode 15 generate electrostatic attraction in a direction substantially parallel to the diaphragm 10.

The first electrode 14 has a fixed portion 14a, which is a portion in a direction substantially parallel to the diaphragm 10 fixed to the diaphragm 10, and a free end portion 14b, which is a long portion in a direction substantially perpendicular to the diaphragm 10. Have. The first electrode 14 is made of, for example, polysilicon.

[0025] Also, the third bonded to the upper surface of the first substrate 1
For the substrate 3, for example, a nickel substrate having a thickness of 50 μm is used, and a fluid resistance portion for communicating the nozzle hole 4, the common liquid chamber 8 and the discharge chamber 6 with the surface portion of the third substrate 3 so as to communicate with the discharge chamber 6, respectively. 7 is provided, and an ink supply port 9 is provided so as to communicate with the common liquid chamber 8.

The operation of the ink jet head thus constructed will be described. For example, the first electrodes 14 and 14 are set to 0
V, and the second electrode 15 is driven from 0V to 4 by a drive circuit.
When a 0 V pulse potential is applied, the surface of the second electrode 15 is charged to a positive potential, and an electrostatic attractive force is generated between the second electrode 15 and the L-shaped first electrode 14 in a direction substantially parallel to the vibration plate 10. As shown in FIG. 3, the vibrating plate 10 is bent toward the ejection chamber 6 by the displacement of the free end of the first electrode 14. As a result, the pressure in the ejection chamber 6 rapidly rises, and ink droplets are ejected from the nozzle holes 4 toward a recording medium such as recording paper.

When the potential of the second electrode 15 which has been supplied with the potential of 40 V returns to 0 V, the potential difference between the electrodes disappears and the electrostatic attractive force disappears, so that the diaphragm 10 is restored to the original state. When the vibration plate 10 is restored, ink is replenished from the common liquid chamber 8 into the ejection chamber 6 through the fluid resistance portion 7. By repeating this, ink droplets can be continuously ejected. That is, this head can eject ink droplets by pushing.

Here, the force F acting between the electrodes is defined by the following (1)
As shown in the formula, it increases in inverse proportion to the square of the inter-electrode distance d. In order to drive at a low voltage, it is important to form a small distance between the first electrode 14 and the second electrode 15.

[0029]

[Equation 1]

In the equation (1), F: force acting between the electrodes, ε: permittivity, S: area of facing surfaces of the electrodes, d:
Distance between electrodes, V: applied voltage.

As described above, since the electrostatic attraction in the direction substantially parallel to the diaphragm is generated between the first electrode on the diaphragm side and the second electrode on the fixed portion side, the diaphragm is displaced. The head can be driven by pushing, the gap area can be increased without increasing the chip area, a large diaphragm displacement can be obtained at a low cost, the droplet ejection efficiency is high, and the head density can be increased. Is obtained.

Here, the first electrode provided on the diaphragm has a shape having a long portion in a direction substantially perpendicular to the diaphragm so that the first electrode on the diaphragm side and the second electrode on the fixed portion side.
The gap between the electrode and the electrode can be formed in a direction substantially perpendicular to the diaphragm (depth direction), and as described above, the electrostatic attraction is generated in the direction substantially parallel to the diaphragm to displace the diaphragm. Can be made.

By making the first electrode have a substantially L-shaped cross section, the displacement of the portion in the direction substantially perpendicular to the diaphragm causes the portion in the direction substantially parallel to the diaphragm to deform the diaphragm. Therefore, a large displacement of the diaphragm can be obtained. Further, by integrally forming the L-shaped electrode on the surface of the vibrating plate, the manufacturing process can be simplified, and a low-cost and highly reliable droplet discharge head can be manufactured.

Furthermore, since the first and second electrodes are arranged separately from the vibration plate, the vibration plate material does not need to be a conductive material and can be pushed, so that ink droplets can be ejected onto the vibration plate. It is not necessary to have enough rigidity to discharge. Therefore, as the diaphragm material, it is possible to use a diaphragm material having a Young's modulus of 1E4MP or less and a low Young's modulus, and an insulating organic polymer resin can also be used. You can select costly materials. This makes it possible to obtain a droplet discharge head having stable characteristics at low cost.

Next, the ink jet head according to the second embodiment will be described with reference to FIG. In addition, this figure is a cross-sectional explanatory view of the same head taken along the lateral direction of the diaphragm.
In this head, the L-shaped first electrode 14 is a portion (fixed portion fixed to the vibration plate 10) 14a parallel to the vibration plate surface.
Is formed to be longer than the length of a portion (free end portion having a free end) 14b perpendicular to the diaphragm surface.

As a result, a large displacement of the fixed portion 14a can be obtained by a slight displacement of the free end portion 14b of the first electrode 14, and the excluded volume can be made larger than that of the first embodiment, thereby increasing the liquid chamber area. The head size can be reduced because the size can be reduced and the density can be further increased.

Further, in the fixed portion 14a of the first electrode 14, a groove (notch portion) 22 is formed in the fixed end side portion of the diaphragm 10 which serves as a fulcrum of rotation of the first electrode 14. As a result, the contact area between the first electrode 14 and the vibration plate 10 is reduced, the rigidity of the vibration plate 10 can be reduced, and further low voltage driving becomes possible.

In this head, a protective tape 23 is provided on the lower surface of the spacer member 12 instead of the second substrate 2.

Next, an example of the manufacturing process of this head will be described with reference to FIGS. As shown in FIG. 5A, by lithography and etching method (litho / etch method) on a silicon substrate 31 having a (100) plane orientation,
A groove 32 having a depth of 4 μm is formed, and then an oxide film 33 having a thickness of 1 μm is formed by the CVD method.

Then, as shown in FIG. 3B, the oxide film 33 on the both ends of the groove 32 having a width of 3 μm is removed by a litho / etch method, and the oxide film 33 is used as a mask to form an L-shaped electrode. To form a groove 34 having a depth of 20 μm. After that, as shown in FIG. 3C, an oxide film 35 having a thickness of 0.3 μm is formed on the surface of the silicon substrate 31 by the thermal oxidation method. Then, as shown in FIG.
4 is filled with polysilicon 36, and the surface is flattened by the CMP method.

After that, as shown in FIG. 6A, a separation groove 37 is formed by a litho / etching method in order to form the two first electrodes 14 in the central portion of the polysilicon 36. A groove 38 is formed to reduce the rigidity.

On the other hand, as shown in FIG.
0) A 2 μm-thick polyester film 43 serving as a vibration plate is attached to a silicon substrate 41 having a plane orientation with an oxide film 42 having a thickness of 0.3 μm, and an insulating film 44 is further laminated. It is bonded to the silicon substrate 31.

The diaphragm material is a material having a low Young's modulus,
In particular, a material having a Young's modulus of 1E4MP or less is preferable. For example, an organic polymer resin such as polyimide or PBO film can be used. Further, not only the insulating organic polymer material, but also a conductive resin such as polypyrrole or polyaniline can be used. By using the conductive resin, the L-shaped electrode 14 and the vibration plate 10 can have the same potential. By using the electrodes, it is possible to easily take out the pads.

Thereafter, as shown in FIG. 6C, the back surface of the silicon substrate 31 is polished until the polysilicon 36 is exposed.

Then, as shown in FIG.
After forming the groove 45 to surround the recon 36 parts,
As shown in (b), litho /
The discharge chamber 6 etc. is formed by the etching method, and is a corrosion resistant film.
Polyimide 46 is applied by spray coating or vacuum deposition.
Film formation. Further, the oxide film 33 on the silicon substrate 31,
35 is removed by an aqueous solution of hydrofluoric acid, and the L-shaped electrode 14 and the
The separate electrode 15 is completed. Finally protection for the backside protection
Stick the tape 49. The oxide films 33 and 35 are removed.
Not only wet etching method but also HF vapor method and chemi
A cal dry etching method may be used. Also the sacrificial layer
If polysilicon is used for the
SF as metal material₆Isotropic dry etch using gas
Gu, XeF ₂Atmospheric pressure chemical etching using gas, etc.
Also, the sacrificial layer can be removed.

Finally, although not shown, a nozzle plate is attached to the surface of the silicon substrate 41 to complete the electrostatic droplet discharge head.

As described above, since it is possible to accurately form the gap by the semiconductor process technology and the sacrifice layer process, which have a proven track record in mass production, a large number of droplet discharge heads having stable characteristics can be manufactured at low cost. It becomes possible to do.

Next, the ink jet head according to the third embodiment will be described with reference to FIG. In this head, the second electrode 15 is arranged inside the two L-shaped first electrodes 14, 14, and each first electrode 14,
The second electrode 16 is also arranged on the outer side of 14. The second electrode 16 also serves as a spacer member.

In this case, in order to form the second electrode 16 on the outer side, for example, in the above-described manufacturing process, when the deep groove 34 for forming the L-shaped first electrode 14 is formed, the second electrode 16 and the adjacent electrode are formed. By forming the deep groove (separation groove) 50 for separation, the oxide film 35 is also formed in the deep groove 50, and by forming the polysilicon 36, the deep groove 50 is filled with the polysilicon 36. In this case, the sacrificial oxide film 35 in the deep groove 50 is removed by removing the sacrificial oxide film 35 between the electrodes and the like while protecting the sacrificial oxide film 35 from the resist.

In this way, the second electrode is sandwiched with the first electrode 14 interposed therebetween.
Electrodes 15, 16 are provided, that is, the second electrode 15 is provided inside the free end portion 14b of the first electrode 14,
By providing the second electrode 16 outside the free end portion 14b of the first electrode 14, it becomes possible to drive by the pull-push-punch method.

That is, as shown in FIG. 9A, the first
With the electrode (common electrode) 14 (common electrode) of 0 V set to 0 V, a pulse potential of 0 V to 40 V is applied to the second electrode (individual electrode for striking) 16 by the oscillation circuit, as shown in FIG. Is applied, the surface of the second electrode 16 is positively charged, and the free end portion 14b of the L-shaped first electrode 14 is charged.
The electrostatic attraction works between the first electrode 14 and the second electrode 16 as shown in FIG. 10, and the first electrode 14 and 14 are pulled toward the outer second electrodes 16 and 16, respectively, so that the diaphragm 10 bends downward. . As a result, ink is replenished from the common liquid chamber 8 into the ejection chamber 6 through the fluid resistance portion 7.

From this state, the potential of the second electrode 16 becomes zero.
When the same pulse potential is applied to the inner second electrode (individual electrode for pushing) 15 as shown in FIG. 9C, the surface of the second electrode 15 is positively charged, Electrostatic attraction acts between the L-shaped first electrode 14 and the free end portion 14b of the L-shaped first electrode 14, and as shown in FIG.
Since 4 and 14 are respectively drawn to the inner side of the second electrode 15, the vibrating plate 10 bends upward, the ink in the ejection chamber 6 is pressurized, and ink droplets are ejected.

Since the vibrating plate 10 can be vertically displaced at any timing in this way, the size of the ejected ink droplet can be reduced by optimizing the voltage application timing in consideration of the ink flow (meniscus or the like). The diaphragm 10 can be driven at high speed while controlling. Further, the displacement amount of the vibration plate can be increased as compared to the case of only push-pushing or pull-pushing, so that the excluded volume of the discharge chamber 6 can be increased, the density can be increased, and the head size can be reduced. You can

Next, the ink jet head according to the fourth embodiment will be described with reference to FIG. In this head, the insulating film 11b formed on the diaphragm 10 is partially thickened, and the columnar first electrodes 14 are provided in the depth direction (direction perpendicular to the diaphragm surface). That is, the first electrode 14
The insulating film 11b also serves as a portion fixed to the diaphragm 10. Even with this configuration, the same operational effects as the above-described embodiment can be obtained.

In each of the above embodiments, the angle formed by the first electrode and the diaphragm surface is not particularly limited,
From the viewpoint of the manufacturing process, the free end portion of the first electrode is preferably perpendicular to the diaphragm surface.

In each of the above embodiments, the piezoelectric material is embedded in the gap 17 between the first electrode 14 and the second electrode 15, and the piezoelectric material is embedded between the first electrode 14 and the second electrode 15. By applying a voltage to cause a volume change due to the inverse piezoelectric effect of the piezoelectric material to displace the diaphragm, it is possible to displace the diaphragm with a force larger than the force generated by the electrostatic force between the electrodes, Further, it becomes easy to control the displacement amount of the diaphragm. As a result, a high-performance and stable droplet discharge head can be obtained.

Next, the ink cartridge integrated head of the droplet discharge head according to the present invention will be described with reference to FIG. This ink cartridge integrated head 100
Is an ink-jet head 101 of any of the above-described embodiments having a nozzle hole 101 and the like, and an ink tank 102 that supplies ink to the ink-jet head 101, which are integrated.

By thus integrating the ink-jet head, which is the droplet discharge head according to the present invention, and the ink tank, the droplet discharge head with high droplet discharge efficiency and stable droplet discharge characteristics is integrated. The obtained ink cartridge (ink tank integrated head) is obtained.

Next, an example of a mechanism of an ink jet recording apparatus equipped with an ink jet head (including an ink cartridge integrated with a head) according to the present invention is shown in FIG.
This will be described with reference to FIGS. 14 is a perspective explanatory view of the recording apparatus, and FIG. 15 is a side view of a mechanical portion of the recording apparatus.

This ink jet recording apparatus has a carriage movable inside the recording apparatus main body 111 in the main scanning direction, a recording head including the ink jet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. Printing mechanism section 11 composed of
A sheet feeding cassette (or a sheet feeding tray) 114 capable of accommodating a large number of sheets 113 from the front side can be detachably attached to the lower portion of the apparatus main body 111 for accommodating 2 or the like. The manual feed tray 115 for manually feeding the paper 113 can be opened and closed, the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in, and a desired image is recorded by the printing mechanism unit 112. After that, the output tray 1 mounted on the rear side
The paper is discharged to 16.

The printing mechanism section 112 slides the carriage 123 in the main scanning direction (the direction perpendicular to the paper surface in FIG. 15) by the main guide rod 121 and the sub guide rod 122, which are guide members which are horizontally mounted on the left and right side plates (not shown). The carriage 123 is freely held, and yellow (Y), cyan (C),
A head 124, which is an ink jet head that is a droplet ejection head according to the present invention that ejects ink droplets of each color of magenta (M) and black (Bk), is arranged in a direction in which a plurality of ink ejection ports intersects the main scanning direction. , The ink droplet ejection direction is downward. Also, the carriage 123
Each ink cartridge 125 for supplying each color ink to the head 124 is replaceably mounted.

The ink cartridge 125 has an atmosphere port communicating with the atmosphere above, a supply port supplying ink to the ink jet head below, and a porous body filled with ink inside. The ink supplied to the inkjet head is maintained at a slight negative pressure by the capillary force of.

Further, although the heads 124 of the respective colors are used here as the recording head, 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 carrying direction) and slidably fitted to the sub guide rod 122 on the front side (upstream side in the paper carrying direction). It is placed in. Then, in order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between the drive pulley 128 and the driven pulley 129 which are rotationally driven by the main scanning motor 127, and the timing belt 130 is mounted on the carriage 123. The carriage 123 is reciprocally driven by the forward and reverse rotations of the main scanning motor 127.

On the other hand, in order to convey the paper 113 set in the paper feed cassette 114 to the lower side of the head 124, the paper feed roller 131 and the friction pad 132 for separating and feeding the paper 113 from the paper feed cassette 114, and the paper 11
Guide member 133 for guiding the sheet 3 and the fed sheet 11
A conveyance roller 134 that reverses and conveys 3 is provided, and a conveyance roller 135 that is pressed against the peripheral surface of the conveyance roller 134 and a leading end roller 136 that defines the feed angle of the paper 113 from the conveyance roller 134. Conveyor roller 1
The sub-scanning motor 137 is rotationally driven through a gear train.

Then, a print receiving member 139, which is a paper guide member for guiding the paper 113 sent out from the carrying roller 134 below the recording head 124, corresponding to the movement range of the carriage 123 in the main scanning direction is provided. There is. A transport roller 141 and a spur 142 that are driven to rotate in order to send the paper 113 in the paper discharge direction are provided on the downstream side of the print receiving member 139 in the paper transport direction, and further, the paper 113 is sent to the paper discharge tray 116. Roller 143 and spur 1
44, and guide members 145 and 146 that form the paper discharge path
And are arranged.

At the time of recording, by driving the recording head 124 in accordance with the image signal while moving the carriage 123, ink is ejected onto the stopped paper 113 to record one line, and the paper 113 is moved by a predetermined amount. After transportation, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 113 reaches the recording area, the recording operation is ended and the paper 113 is ejected. In this case, the head 12
In the ink jet head according to the present invention, which composes No. 4, the controllability of ink droplet ejection is improved and the characteristic variation is suppressed, so that an image with high image quality can be stably recorded.

Further, a recovery device 147 for recovering the ejection failure of the head 124 is arranged at a position outside the recording area on the right end side of the carriage 123 in the moving direction. The recovery device 147 has a cap means, a suction means, and a cleaning means. The carriage 123 is moved to the recovery device 147 side while the printing is on standby, the head 124 is capped by the capping means, and the ejection port portion is kept wet to prevent ejection failure due to ink drying.
Also, by ejecting ink that is not related to recording during recording, etc., the ink viscosity of all ejection ports is made constant,
Maintains stable discharge performance.

When ejection failure occurs, the ejection port (nozzle) of the head 124 is sealed with a capping means,
Bubbles and the like are sucked out together with the ink from the discharge port by the suction means through the tube, and the ink and dust adhering to the surface of the discharge port are removed by the cleaning means to recover the discharge failure. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed in the lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.

As described above, since this ink jet recording apparatus is equipped with the ink jet head which is the liquid droplet ejection head according to the present invention, the density can be increased and the image quality can be improved.

Next, a micro pump as a micro device to which the actuator portion of the droplet discharge head according to the present invention is applied will be described with reference to FIG. It should be noted that the figure is a cross-sectional explanatory view of the main parts of the micropump.
This micropump has a laminated structure in which a flow channel substrate 201 and a counter substrate (counter member or fixing member) 202 are stacked and bonded via a spacer portion 209, and a flow channel through which a fluid flows in the flow channel substrate 201. Deformable movable plate 2 which forms 203 and also forms one wall surface of the flow path 203.
04 (corresponding to the diaphragm of the head) is provided, and the movable plate 2 is provided.
A portion of 04, which is not bonded and fixed to the counter substrate 202, is a movable portion 205.

Then, the flow path substrate 201 and the counter substrate 202
In the space 208 formed between the movable part 205 and
In the same manner as the ink jet head, two L-shaped first electrodes 207a are provided on the outer surface side via an insulating film 206, and a second electrode (fixed electrode) 2 is also provided on the counter substrate 202 side.
07b is provided. The arrangement and materials of the electrodes are the same as in the above-described head embodiment.

The operating principle of this micropump will be described. As described above, the first electrode 207a is selectively applied with the pulse potential to the second electrode 207b.
Since an electrostatic attraction force is generated between the second electrode 207b and the second electrode 207b, the first electrode 207a is displaced and the movable portion 205 is moved to the flow path 20.
Deforms to side 3. Here, by sequentially driving the movable part 205 from the right side in the drawing, the fluid in the flow path 203 flows in the direction of the arrow, and the fluid can be transported.

In this case, by providing the actuator of the droplet discharge head according to the present invention, the displacement efficiency of the movable part is improved and the amount of bending of the diaphragm can be increased, so that the performance of the micropump is greatly improved. In addition, although an example in which a plurality of movable parts is provided is shown in this embodiment, the number of the movable parts may be one. Also, one or more valves, such as a check valve, may be provided between the moving parts to increase transport efficiency.

Next, an example of an optical device to which the actuator portion of the droplet discharge head according to the present invention is applied will be described with reference to FIG. The figure is a schematic configuration diagram of the device. This optical device includes a deformable mirror 301 and a counter substrate (a counter member or a fixing member) 3
02 and 02 are overlapped and joined via a spacer 309,
The portion of the mirror 301 that is not bonded and fixed to the counter substrate 302 is a movable portion 305. A dielectric multilayer film or a metal film may be formed on the surface of the mirror 301 to increase the reflectance.

Then, the movable portion 305 and the counter substrate 302
In the space 308 formed between
Similarly to the ink jet head, two L-shaped first electrodes 307a are provided on the outer surface side via the insulating film 306, and the second electrode (fixed electrode) 30 is also provided on the counter substrate 302 side.
7b is provided. The arrangement and materials of the electrodes are the same as in the above-described head embodiment.

Explaining the principle of this optical device, as described above, by selectively applying a pulse potential to the second electrode 307b, electrostatic attraction between the first electrode 307a and the second electrode 307b is performed. Since a force is generated, the movable portion 305 is deformed into a convex shape by the displacement of the first electrode 307a and becomes a convex mirror. Therefore, the light source 3
When the light from 10 irradiates the mirror 301 through the lens 311, the light is reflected at the same angle as the incident angle when the mirror 301 is not driven, but when the movable portion 305 of the mirror 301 is driven, the movable portion is moved. Since 305 serves as a convex mirror, the reflected light becomes divergent light. Thereby, an optical modulation device can be realized.

By providing the actuator of the droplet discharge head of the present invention, the displacement efficiency of the movable portion is improved,
Since the amount of bending of the movable portion can be increased, the performance of the optical mirror can be greatly improved.

Therefore, an example in which this optical device is applied will be described with reference to FIG. In this example, the above-mentioned optical devices are arranged two-dimensionally, and the movable portion 305 of each mirror is arranged.
Is driven independently. Although a 4 × 4 array is shown here, more arrays are possible.

Therefore, as in the case of FIG. 17 described above, the light from the light source 310 passes through the lens 311 and the mirror 301.
The light that is applied to the area where the mirror 301 is not driven enters the projection lens 312. On the other hand, a portion where the movable portion 305 of the mirror 301 is deformed by applying a voltage to the second electrode 307b becomes a convex mirror, so that light diverges and hardly enters the projection lens 312. The light incident on the projection lens 312 is projected on a screen (not shown) or the like, and an image can be displayed on the screen.

In the above-described embodiment, an example in which the ink-jet head is used as the liquid-drop discharge head has been described. However, as a liquid-drop discharge head other than the ink-jet head, for example, a liquid-drop discharge for discharging a liquid resist as a liquid drop. The present invention can also be applied to other droplet discharge heads such as a head and a droplet discharge head that discharges a DNA sample as droplets. In addition to the micro pump and the optical device (light modulation device), the actuators that compose the droplet discharge head include micro switches (micro relays), multi-optical lens actuators (optical switches), micro flow meters, pressure sensors, etc. Can also be applied to.

[0082]

As described above, according to the droplet discharge head of the present invention, the diaphragm is provided with the first electrode, and the fixed portion facing the diaphragm is provided with the second electrode. Since the diaphragm is deformed by generating an electrostatic force in a direction substantially parallel to the diaphragm between the electrode and the second electrode, at low cost,
A large vibration plate displacement can be obtained, a droplet ejection efficiency is high, and a head capable of high density can be obtained.

According to the droplet discharge head of the present invention, the vibrating plate is provided with the first electrode, the fixing portion facing the vibrating plate is provided with the second electrode, and the first electrode and the second electrode are provided. Since a piezoelectric material is enclosed between the and, and the diaphragm is deformed by the inverse piezoelectric effect of the piezoelectric material, a large displacement of the diaphragm can be obtained at a low cost, a droplet ejection efficiency is high, and a head capable of high density can be obtained. can get.

According to the ink jet recording apparatus of the present invention, since the ink jet head for ejecting ink droplets is the liquid droplet ejection head of the present invention, high image quality recording can be performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating an inkjet head according to a first embodiment of a droplet discharge head of the invention.

FIG. 2 is an explanatory cross-sectional view of the same head taken along the lateral direction of the diaphragm.

FIG. 3 is an enlarged cross-sectional explanatory view of an essential part for explaining the operation of the head.

FIG. 4 is an explanatory cross-sectional view taken along the lateral direction of the diaphragm of the inkjet head according to the second embodiment.

FIG. 5 is an explanatory diagram illustrating an example of a manufacturing process of the head.

FIG. 6 is an explanatory diagram illustrating a step following FIG.

FIG. 7 is an explanatory diagram illustrating a step following FIG.

FIG. 8 is an explanatory cross-sectional view taken along the lateral direction of the diaphragm of the inkjet head according to the third embodiment.

FIG. 9 is an explanatory diagram of drive waveforms for explaining the operation of the head.

FIG. 10 is an enlarged explanatory view of a main part for explaining the operation of the head.

FIG. 11 is an enlarged explanatory view of a main part for explaining the operation of the head.

FIG. 12 is an explanatory cross-sectional view taken along the lateral direction of the diaphragm of the inkjet head according to the fourth embodiment.

FIG. 13 is a perspective explanatory view for explaining an ink cartridge integrated head including a droplet discharge head according to the present invention.

FIG. 14 is a perspective explanatory view illustrating an example of an inkjet recording apparatus according to the present invention.

FIG. 15 is an explanatory diagram of a mechanical section of the recording apparatus.

FIG. 16 is an explanatory diagram illustrating an example of a micropump to which the actuator portion of the droplet discharge head according to the present invention is applied.

FIG. 17 is an explanatory diagram illustrating an example of an optical device to which the actuator portion of the droplet discharge head according to the present invention is applied.

FIG. 18 is a perspective explanatory view illustrating an example of a light modulation device using the optical device.

[Explanation of symbols]

1 ... 1st substrate, 2 ... 2nd substrate, 3 ... Nozzle plate, 4 ... Nozzle hole, 6 ... Discharge chamber, 7 ... Fluid resistance part, 8 ... Common liquid chamber, 1
0 ... Vibration plate, 12 ... Spacer member, 14 ... First electrode,
15, 16 ... Second electrode, 100 ... Ink cartridge integrated head, 124 ... Recording head, 201 ... Flow path substrate, 203 ... Flow path, 205 ... Movable part, 207 ... Electrode,
301 ... Mirror, 305 ... Movable part, 307 ... Electrode.

Claims (11)

[Claims] 1. A droplet discharge head comprising a vibrating plate forming at least one wall surface of a pressurizing chamber communicating with a nozzle for ejecting a droplet, and deforming the vibrating plate to eject the droplet. A first electrode is provided on the diaphragm, a second electrode is provided on a fixed portion facing the diaphragm, and a direction substantially parallel to the diaphragm is provided between the first electrode and the second electrode. A droplet discharge head, characterized in that the diaphragm is deformed by generating the electrostatic force. 2. The droplet discharge head according to claim 1, wherein the first electrode has a portion that is long in a direction substantially perpendicular to the vibration plate surface. 3. The droplet discharge head according to claim 1, wherein the first electrode has a substantially L-shaped cross section. 4. The droplet discharge head according to claim 3, wherein the first electrode having an L-shaped cross section is substantially parallel to the vibrating plate rather than a length of a portion in a direction substantially perpendicular to the vibrating plate surface. A droplet discharge head characterized in that the length of the portion in the direction is long. 5. The droplet discharge head according to claim 1, wherein the second electrode is arranged inside the first electrode. 6. The liquid droplet ejection head according to claim 1, wherein the second electrode is arranged outside the first electrode. 7. The droplet discharge head according to claim 1, wherein the diaphragm has a Young's modulus of 1E4.
A droplet discharge head characterized by being equal to or lower than MP. 8. The droplet discharge head according to claim 1, wherein the vibrating plate is made of an insulating organic polymer material. 9. The droplet discharge head according to claim 1, wherein a fulcrum portion of the second electrode is not fixed to the vibration plate. 10. A droplet discharge head comprising a vibrating plate forming at least one wall surface of a pressurizing chamber communicating with a nozzle for ejecting a droplet, and deforming the vibrating plate to eject the droplet. A first electrode is provided on the diaphragm,
A second electrode is provided on a fixed portion facing the diaphragm, a piezoelectric material is enclosed between the first electrode and the second electrode, and the diaphragm is deformed by an inverse piezoelectric effect of the piezoelectric material. A liquid droplet ejection head, characterized in that 11. An ink jet recording apparatus having an ink jet head for ejecting ink droplets, wherein the ink jet head is the liquid droplet ejecting head according to any one of claims 1 to 10.