JPH11198372A - Ink jet head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To densify an interval of dots on a recording medium due to an ink to be discharged while reducing a production cost. SOLUTION: This ink jet head discharges an ink 306 in an ink channel 307 from a nozzle 305 based on a displacement of a diaphragm 302 for forming one surface of the channel 307 in a direction of an arrow D1. In this head, a pressure generating chamber 303 in which a fluid dielectric substance is charged is disposed adjacent to the channel 307 via the diaphragm 302, and the diaphragm 302 is displaced based on a voltage applied between individual electrodes 312 and a common electrode 313 provided on upper and lower surfaces of the chamber 303.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet head, and more particularly to an ink-jet head for discharging ink in a container from a nozzle based on displacement of a diaphragm serving as one surface of a predetermined container, and a method of manufacturing the same. .

[0002]

2. Description of the Related Art An ink jet printer using a piezoelectric element as a print head has been known.
In such an ink-jet head (print head of an ink-jet printer), a pulse voltage corresponding to image data is applied to a piezoelectric element, and a distortion of the piezoelectric element (PZT) caused by the application of the pulse voltage causes an ink channel as a predetermined container. Is pressurized, and ink drops are ejected from a nozzle provided in the ink channel toward a recording sheet such as paper, an OHP sheet, or the like.
An image based on image data transmitted from a personal computer or the like is printed on the recording sheet by discharging these ink drops.

[0003] Such an ink jet head will be described in detail with reference to FIGS. 7 and 8 show such a conventional ink jet head. (The overall configuration of the ink jet printer having the conventional ink jet head is based on the ink jet printer of the embodiment of the present invention shown in FIG. 1.) FIG.
FIG. 8 is a cross-sectional view taken along a plane in the main scanning direction, including FIG. 5, and FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG.

As shown in FIG. 7, a conventional ink jet head includes a nozzle plate 201, a diaphragm 202, a PZ
T203 and a ceramic substrate 204 are integrally laminated.

[0005] The nozzle plate 201 is made of metal, ceramic, or the like, and has nozzles 205. Diaphragm 20
2, a thin film is used and is fixed between the nozzle plate 201 and the PZT 203. Further, between the nozzle plate 201 and the diaphragm 202,
Plurality of ink channels 207 containing ink 206
And an ink inlet 209 for connecting each ink channel 207 to the ink supply chamber 208. The ink supply chamber 208 is connected to an ink cartridge (not shown), and the ink 206 in the ink supply chamber 208 is supplied to an ink channel 207.

[0006] The surface of the PZT 203 which is in contact with the diaphragm 202 is connected to the driver circuit 21 via a flexible wiring 211.
PZT2 connected to the inkjet head
The common electrode side wiring portion 213 connected to the ground is provided on the ceramic substrate 204 and is connected to the plurality of PZTs 203 in the ink jet head. . PZ
T203 is a sheet-like two electrodes and a sheet-like PZT
And the individual electrode side wiring portion 212 is connected to one of the two sheet-like electrodes which are individual electrodes in the PZT 203, and the common electrode side wiring portion 2
Reference numeral 13 denotes a sheet-like 2 serving as a common electrode in the PZT 203.
Connected to the other of the two electrodes.

In such a conventional ink jet head, a predetermined voltage corresponding to image data is applied between the individual electrodes of the PZT 203 and the common electrode, and the diaphragm 20
2 deforms in the direction in which the ink channel 207 is pushed. Due to the deformation of the vibration plate 202, the ink 206 in the ink channel 207 is pressurized, the ink drop flies toward the recording sheet via the nozzle 205, and an image is recorded based on the flying of the ink drop.

When manufacturing such a conventional ink jet head, first, PZT 203 and PZT 203 are used.
A plate-shaped laminated P including the T column 215
ZT is fixed on the substrate 204 by an adhesive, and then
The PZT 203 and the PZT pillar 214 (see FIG. 8) are separated by a dicer or the like, and separate grooves 215 and 216 are formed.

[0009]

However, when PZT is used in a conventional ink jet head as described above, there is no PZT processing method at 150 npi (nozzle pitch 169 μm) or more, and 180 npi (nozzle pitch 141 μm) or more. Makes it difficult to mount PZT and wiring to PZT.
Since the ejection becomes impossible due to a decrease in the generated force and the displacement amount due to the ZT drive, there is a limit in increasing the density of the intervals between the dots on the recording sheet due to the flying ink drops. In addition, the production process of the conventional inkjet head as described above is very complicated by including PZT,
High production costs.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and an object of the present invention is to increase the density of dots on a recording medium by ink ejected while reducing production costs. It is an object of the present invention to provide an inkjet head and a method for manufacturing the inkjet head.

[0011]

According to a first aspect of the present invention, ink in the first container is ejected from a nozzle to a recording medium based on displacement of a diaphragm serving as one surface of the first container. This is an inkjet head to be used.

In this ink jet head, the second container is adjacent to the first container with the above-mentioned diaphragm interposed therebetween, and the voltage is applied to the fluid dielectric filled in the second container. It is characterized in that the diaphragm is displaced based on this.

According to the first aspect of the present invention, the second container is adjacent to the first container with the vibration plate interposed therebetween,
The diaphragm is displaced based on applying a voltage to the fluid dielectric filled in the container. This simplifies the configuration without using a piezoelectric element as in the past,
The production cost is reduced, and the density of the dots on the recording medium by the ejected ink can be increased.

According to a second aspect of the present invention, there is provided a method according to claim 1, wherein
This is a method of manufacturing an ink jet head that discharges ink in a container from a nozzle to a recording medium based on displacement of a diaphragm serving as a surface.

The method of manufacturing an ink jet head according to the present invention is characterized in that the above-described container is formed by etching a wafer by anisotropic etching and joining a plate having nozzles.

According to the second aspect of the present invention, the container is formed based on the fact that the wafer is etched by anisotropic etching and the plate having the nozzles is joined. As a result, the manufacturing process can be simplified, the production cost can be reduced, and the density of dots of the ejected ink on the recording medium can be increased.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet head according to an embodiment of the present invention will be described with reference to the drawings. First, an inkjet head according to a first embodiment of the present invention will be described.

FIG. 1 is a perspective view showing a schematic configuration of an ink jet printer 1 having an ink jet head 3 according to the first embodiment.

The ink jet printer 1 is used for paper or OH
An inkjet head 3 that is an inkjet print head that prints on a recording sheet 2 that is a recording medium such as a P sheet; a carriage 4 that holds the inkjet head 3 and is driven by a motor (not shown);
Oscillating shafts 5 and 6 for reciprocating the carriage 4 in parallel with the recording surface of the recording sheet 2, and idle pulleys 7 and 8 for changing the rotation of the motor into the reciprocating motion of the carriage 4.
And a timing belt 9.

The ink jet printer 1 has a paper feed tray 10 for feeding the recording sheets 2, a feed roller 16 which is rotated by gears 12 to 15 driven by a drive motor 11 and conveys the recording sheets 2. A platen 17 which also serves as a guide plate for guiding the recording sheet 2 along the transport path and forms a recording portion by facing the ink jet head 3, and a discharge roller 18 for discharging the recording sheet 2 after recording. I have.

The carriage 4 main-scans the recording sheet 2 in the horizontal direction along swing shafts 5 and 6 by motors (not shown), idle pulleys 7 and 8 and a timing belt 9, and an inkjet head mounted on the carriage 4. 3 is 1
Record the image for the line. Each time recording for one line is completed, the recording sheet 2 fed from the paper feed tray 10 is sub-scanned in the vertical direction by the drive motor 11, the gears 12 to 15, and the feed roller 16, and the next line is recorded. .

The image is recorded on the recording sheet 2 in this manner, and the recording sheet 2 that has passed through the recording section is discharged by a discharge roller 18 disposed on the downstream side in the transport direction.

Next, the structure and operation of the ink jet head 3 and a method of manufacturing the same will be described with reference to FIGS.

FIG. 2 is a cross-sectional view of the ink jet head 3 in a plane including the nozzles 305 in the main scanning direction.

The ink jet head 3 includes a nozzle plate 301, a channel plate 317, a diaphragm 302,
The common electrode 313, the pressure generating chamber 303, and the individual electrode 312 are stacked.

As shown in FIG. 2, a plurality of ink channels 307 for accommodating ink 306 are formed in the ink jet head 3 by a nozzle plate 301 having nozzles 305, a channel plate 317, and a vibration plate 302. An ink inlet 309 that connects the ink channel 307 to a common ink supply chamber 308 is formed. The ink supply chamber 308 is connected to an ink cartridge (not shown).
Is supplied to the ink channel 307.

A pressure generating chamber 303 is provided for each of the ink channels 307 provided in the ink jet head 3. The pressure generating chamber 303 is filled with a flowing dielectric, and a common electrode 313 and an individual electrode 312 are formed so as to sandwich the pressure generating chamber 303. The common electrode 313 is commonly connected to the ground for each ink channel 307, and the individual electrode 312 is formed individually for each ink channel 307, and the flexible wiring 3
11 is connected to the driver circuit 310.

A predetermined voltage corresponding to the image data is applied between the individual electrode 312 and the common electrode 313, and a distortion corresponding to this is generated in the flowing dielectric in the pressure generating chamber 303. Due to this distortion, the diaphragm 302 is pushed in the direction of the arrow D1, and the ink 306 in the ink channel 307 becomes an ink drop from the nozzle 305 and becomes a recording sheet 2 (FIG. 1).
See).

FIG. 3 is a diagram for explaining a method of manufacturing the ink jet head 3. In FIG. 3, the circled numbers indicate the order of the main steps of the inkjet head 3.

As shown in FIG. 3, in manufacturing the ink jet head 3, first, a double-sided lapping of a Si wafer is performed at 0.2 mmt (Step 1), and an oxide film is formed on both sides of the Si wafer (Step 2). Then, a resist is applied to the surface, and exposure and development are performed.

Subsequently, the oxide film on the surface of the Si wafer is etched (step 3), and anisotropic etching of Si is performed at 5 μm (step 4), and boron doping is performed. The layer on which boron doping is performed is an etching stop layer that will later become a diaphragm. After this, 10μ
Diffusion is performed at mt (step 5), the oxide film on the surface is removed, an electrode is formed, and exposure and development are performed. Next, the electrode is etched (step 6) and S
iO2 is deposited, a resist is applied to the back surface, and exposure and development are performed.

Further, the oxide film on the back surface is etched (Step 7), and the back surface is subjected to Si anisotropic etching at 180 μmt (Step 8). Subsequently, after the nozzle plate is anodically bonded (step 9), the front side is filled with a flowable dielectric, and the front lid having electrodes formed on the ink channel side is bonded to complete the ink jet head.

By using the anisotropic etching of Si in this manner, the method of manufacturing the ink jet head and the structure of the ink jet head manufactured by the method are simplified, and the production cost can be reduced as compared with the related art.

Further, by using a flowable dielectric to drive the diaphragm of the ink jet head, 180
Even if the density is increased to npi or more, it is possible to sufficiently discharge ink, and since the fluid dielectric is driven by voltage, it is only necessary to use a drive circuit based on an inexpensive gate element for the drive circuit. .

The displacement of the diaphragm 302 (see FIG. 2) by the ink jet head 3 will be described. [Table 1] shows the calculation results of the displacement of the diaphragm 302 (common electrode 313) of the inkjet head 3. here,
F: force acting on one electrode, εr: relative dielectric constant of fluid dielectric, εo: dielectric constant of vacuum (= 8.854 × 10 ⁻¹² [F
/ M]), S: area of one electrode, V: voltage between electrodes,
d: distance between electrodes, Δx: displacement, l: length of short side of rectangular partition, h: thickness of diaphragm, E: Young's modulus, P:
Generated pressure, ΔV: displacement volume, L: length of the long side of the partition wall, F = 1/2 × εr · εo × SV ² / d ² , Δx =
0.0284 × l ⁴ / (E · h ³ ) × P, ΔV = 8/1
5 × L × 1 × Δx. In order for the ink drop to fly from the nozzle 305, the generated pressure is 0.3
[MPa] or more, and the displacement volume is required to be 30 [pl] or more.

[0036]

[Table 1]

[Table 1] As shown in A and B, the thickness of the partition (diaphragm 302), the distance between the electrodes, the length of the short side and the length of the rectangular partition, and the length of the pressure generating chamber 303 Is set, and the voltage applied between the electrodes is changed to 100 or 75 [V].

When the voltage applied between the electrodes is 100 [V] ([Table 1] A), the generated pressure is 0.5305 [M
Pa], and the displacement volume is determined to be 33.1 [pl].
[V] ([Table 1] B), the generated pressure was 0.2
The displacement volume is determined to be 984 [MPa] and the displacement volume is determined to be 29.9 [pl].

The generated pressure and displacement volume obtained as described above satisfy both of the above-mentioned conditions, and the ink drop can fly stably.

Next, an ink jet head according to a second embodiment of the present invention will be described.

FIG. 4 is a cross-sectional view in the main scanning direction including the nozzles of the ink jet head of the second embodiment. FIG. 5 is a diagram for explaining the nozzle surface of the present inkjet head. FIG. 5A is a diagram illustrating a nozzle surface of the present inkjet head, and FIG. 5B is a diagram illustrating a portion A of the present inkjet head illustrated in FIG.

FIG. 4 showing the ink jet head of the second embodiment corresponds to FIG. 2 showing the ink jet head of the first embodiment, and FIGS. 4 and 5 have the same functions as FIG. The same reference numerals are used for the parts.

In the ink jet head of the first embodiment, the vibration plate 302 is displaced in a direction perpendicular to the nozzle surface (the direction of arrow D1 in FIG. 2), whereas in the ink jet head of the second embodiment, The vibration plate 302 is provided on the side wall of the ink channel 307, and is displaced in a direction parallel to the nozzle surface (the direction of arrow D2 in FIG. 5B).

In the present ink jet head, similarly to the ink jet head of the first embodiment, the pressure generating chamber 30 is formed.
3 is filled with a fluid dielectric, a predetermined voltage corresponding to image data is applied between the individual electrode 312 and the common electrode 313, and the diaphragm is distorted in a direction parallel to the nozzle surface of the fluid dielectric. 302 is pushed in the direction of arrow D2, and the ink 306 in the ink channel 307 becomes an ink drop from the nozzle 305 and flies toward the recording sheet 2 (see FIG. 1).

FIG. 6 is a diagram for explaining a method of manufacturing the present ink jet head. In FIG. 6, as in FIG.
The circled numbers indicate the order of the main steps of the inkjet head.

As shown in FIG. 6, in the production of the present ink jet head, first, both sides of a Si wafer are lapped at 0.3 mmt (Step 1), and after an oxide film is formed on the surface of the Si wafer (Step 2), The surface is sputtered with Cr and Au. Subsequently, a resist is applied to the surface of the Si wafer, exposure and development are performed, and the surface of the Si wafer is etched by Cr and Au.

Thereafter, the oxide film on the surface of the Si wafer is etched (Step 3), and the Si anisotropic etching (Rea) is performed.
active ion etching (RIE) is performed (step 4). Next, CVD is applied to the surface of the Si wafer.
(Chemical Vapor Deposition
An electrode was formed by the n) method (Step 5), the surface oxide film was removed (Step 6), the channel was made hydrophilic, the ease of ink flow was improved, bubbles were prevented from remaining, and a voltage was applied between the electrodes. CVD for preventing migration and electric discharge
A protective film such as SiO2 is formed on the surfaces of the flow paths and the electrodes by the method.

Thereafter, the nozzle plate is attached to the surface of the Si wafer (Step 7) to form a pressure generating chamber, and a fluid dielectric (ferroelectric liquid crystal) is injected into the pressure generating chamber to complete an ink jet head. I do.

By using the anisotropic etching of Si in this manner, the method of manufacturing the ink jet head and the structure of the ink jet head manufactured by the method are simplified, and the production cost can be reduced as compared with the related art.

Further, by using a fluid dielectric to drive the diaphragm of the ink jet head, 180
Even if the density is increased to npi or more, it is possible to sufficiently discharge ink, and since the fluid dielectric is driven by voltage, it is only necessary to use a drive circuit based on an inexpensive gate element for the drive circuit. .

The displacement of the diaphragm 302 (see FIG. 5B) by the ink jet head according to the second embodiment as described above will be described. [Table 2] and [Table 3] show calculation results of the displacement of the diaphragm 302 (individual electrode 312 or common electrode 313) of the inkjet head. Here, F: the force acting on one electrode, Δx: the amount of displacement, and ΔV: the displacement volume are obtained in the same manner as in the calculation in the ink jet head of the first embodiment. Further, in order for the ink drop to fly from the nozzle 305, the generated pressure needs to be 0.3 [MPa] or more and the displacement volume needs to be 30 [pl] or more.

[0052]

[Table 2]

[0053]

[Table 3]

[Table 2] A, B, [Table 3] As shown in C and D, the thickness of the partition (diaphragm 302) and the distance between the electrodes are set, and the length of the short side of the rectangular partition is set. The area is changed by changing the length of the long side, and the voltage applied between the electrodes and the relative permittivity of the fluid dielectric filled in the pressure generating chamber 303 are changed. (When a material in which BaTiO3 is dispersed is used as a fluid dielectric, εr = 1000.)
[Table 2] A, B, [Table 3] In the case of A among C and D,
It satisfies the above conditions of generated pressure and displacement volume,
A stable ink drop flight becomes possible.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of an inkjet printer 1 having an inkjet head 3 according to a first embodiment.

FIG. 2 is a cross-sectional view of a plane including a nozzle 305 of the inkjet head 3 in a main scanning direction.

FIG. 3 is a diagram for explaining a method of manufacturing the inkjet head 3.

FIG. 4 is a cross-sectional view in a main scanning direction including nozzles of an inkjet head according to a second embodiment.

FIG. 5 is a diagram illustrating a nozzle surface of the present inkjet head.

FIG. 6 is a diagram for explaining a method for manufacturing the present inkjet head.

FIG. 7 is a cross-sectional view in a main scanning direction including a nozzle 206 of a conventional inkjet head.

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inkjet printer 2 recording sheet 3 inkjet head 4 carriage 5, 6 swing shaft 7, 8 idle pulley 9 timing belt 10 paper feed tray 11 drive motor 12 to 15 gear 16 feed roller 17 platen 18 discharge roller 301 nozzle plate 302 diaphragm 303 Pressure generation chamber 305 Nozzle 306 Ink 307 Ink channel 308 Ink supply chamber 309 Ink inlet 310 Driver circuit 311 Flexible wiring 312 Individual electrode 313 Common electrode 317 Channel plate

Claims (2)

[Claims] 1. An ink jet head for discharging ink in a first container from a nozzle to a recording medium based on displacement of a diaphragm serving as one surface of a first container, wherein the first container A second container is adjacent to the diaphragm with the diaphragm interposed therebetween, and the diaphragm is displaced based on applying a voltage to a fluid dielectric filled in the second container. Inkjet head. 2. A method for manufacturing an ink jet head for discharging ink in a container from a nozzle to a recording medium based on displacement of a diaphragm serving as one surface of a predetermined container, wherein the wafer is anisotropically etched. A method of manufacturing an ink-jet head, wherein the container is formed based on joining by etching a plate having nozzles.