JP3206251B2 - Ink ejecting apparatus and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet apparatus and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a drop-on-demand type ink jet printer head using piezoelectric ceramics has been proposed as a printer head. This is because, by changing the volume of the ink liquid chamber by deformation of the piezoelectric ceramics, the ink in the ink liquid chamber is ejected as droplets from the nozzle when the volume decreases, and when the volume increases, the ink enters the ink liquid chamber from the other ink introduction path. Ink is introduced. A large number of such ink liquid chambers are arranged close to each other, and ink droplets are ejected from a nozzle at a desired position in accordance with desired print data. An image is formed.

[0003] For example, Japanese Patent Application Laid-Open Nos. 63-27051 and 63-252 disclose such an ink ejecting apparatus.
750 and JP-A-2-150355. FIGS. 3, 4, 5, 6, and 7 are schematic diagrams of these conventional examples.

FIG. 3 is a sectional view of an ink ejecting apparatus.
Thus, the configuration of the conventional example will be specifically described. An arrow 4 having a plurality of grooves 15 and side walls 11 separating the grooves 15;
Ceramics plate 1 polarized in the direction of
And a cover plate 2 made of a ceramic material or a resin material or the like, and a bonding layer 3 made of an epoxy-based adhesive or the like.
The groove 15 becomes a plurality of ink liquid chambers 12 spaced apart from each other in the lateral direction. Ink chamber 12
Has an elongated shape with a rectangular cross section, and the side wall 11 extends over the entire length of the ink liquid chamber 12. Electrodes 13 for applying a driving voltage are formed on both surfaces from the upper portion of the side wall 11 near the adhesive layer 3 to the center of the side wall 11. All the ink liquid chambers 12 are filled with ink.

Next, FIG. 4 shows a cross-sectional view of the ink ejecting apparatus.
The operation of the conventional example will now be described. In the ink ejecting apparatus, for example, when the ink liquid chamber 12b is selected according to desired print data, a positive drive voltage is rapidly applied to the electrodes 13e and 13f, and the electrodes 13d and 13g are grounded. As a result, a driving electric field in the direction of arrow 14b acts on the side wall 11b, and a driving electric field in the direction of arrow 14c acts on the side wall 11c. At this time, since the driving electric field directions 14b and 14c are orthogonal to the polarization direction 4, the side walls 11b and 11c
Is rapidly deformed toward the inside of the ink liquid chamber 12b due to the piezoelectric thickness-shear effect. Due to this deformation, the volume of the ink liquid chamber 12b is reduced, the ink pressure in the ink liquid chamber 12b is rapidly increased, and a pressure wave is generated.
An ink droplet is ejected from a nozzle 32 (FIG. 5) communicating with the ink jet head. When the application of the driving voltage is stopped, the side walls 11b
11c return to the position before deformation (see FIG. 3), the ink pressure in the ink liquid chamber 12b drops, and the ink supply port 2
1 (FIG. 5) is supplied to the ink chamber 12b through the manifold 22 (FIG. 5).

In the conventional example, since ink droplets cannot be simultaneously ejected from two nozzles communicating with two adjacent ink liquid chambers, for example, nozzles communicating with odd-numbered ink liquid chambers 12a and 12c from the left end After the ink droplets are ejected from the ink liquid chambers 12b and 12d, the ink droplets are ejected from the nozzles communicating with the even-numbered ink liquid chambers 12b and 12d, and then the ink droplets are ejected again from the odd-numbered ink chambers. And the nozzles 32 are divided into a plurality of groups to eject ink droplets.

However, the above operation is only a basic operation of the conventional example, and when embodied as a product, a driving voltage is first applied in a direction of increasing the volume, and the ink liquid chamber 12b is first applied.
Stop supplying drive voltage after supplying ink to
The ink may be ejected by returning the side walls 11b and 11c to the position before deformation (see FIG. 3).

Next, FIG. 5 shows a perspective view of the ink ejecting apparatus.
The configuration and manufacturing method of the conventional example will be described. The parallel grooves 1 forming the ink liquid chambers 12 having the above-mentioned shape are formed on the piezoelectric ceramic plate 1 that has been subjected to the polarization treatment by grinding using a thin disk-shaped diamond blade or the like.
5 is produced. The groove 15 is a parallel groove having the same depth over substantially the entire area of the piezoelectric ceramic plate 1, but is gradually made shallower as approaching the end face 17, and is formed so as to be shallow and parallel shallow groove 18 near the end face 17. Electrodes are formed on the inner surfaces of the groove 15 and the shallow groove 18 by vacuum deposition, sputtering, or the like. When the individual electrodes are formed, the electrodes are also formed on the zenith of the side wall 11, so that it is necessary to separate the electrodes on both sides of the side wall 11, and therefore, the electrodes on the zenith of the side wall 11 are removed. Thus, the electrode 13 is formed only on the upper half of the side surface on the inner surface of the groove 15, and the shallow groove 18 is formed.
An electrode 19 is formed on the entire inner surface of the substrate. The electrodes 13 formed on the side walls 11 on both sides of the groove 15 are electrically connected by the electrodes 19.

An ink inlet 21 and a manifold 22 are formed on the cover plate 2 made of a ceramic material or a resin material by grinding or cutting.

Next, the grooves 1 of the piezoelectric ceramic plate 1
5 The surface on the processing side and the surface on the processing side of the manifold 22 of the cover plate 2 are adhered by the epoxy adhesive 3 (FIG. 3) or the like so that each groove 15 forms the ink liquid chamber 12 having the above-mentioned shape. I do. Next, the ink liquid chambers 1 are provided on the end faces 16 of the piezoelectric ceramic plate 1 and the cover plate 2.
The nozzle plate 31 provided with the nozzles 32 is bonded at a position corresponding to the position 2. On the surface of the piezoelectric ceramic plate 1 opposite to the groove 15 processing side, each ink liquid chamber 12 is provided.
The substrate 41 on which the conductive layer pattern 42 is provided at a position corresponding to the position is bonded by an epoxy adhesive or the like.

Then, the electrode 19 on the bottom of the shallow groove 18 and the pattern 42 of the conductive layer are connected by a conductive wire 43. Normally, a known technique called wire bonding is used for such connection. Since the diameter of the conductive wire 43 is usually very small and the mechanical strength is small, in order to prevent contact and disconnection between the adjacent conductive wires 43 and corrosion by moisture or dust in the air, a resin such as an epoxy resin is generally used. The formation (potting) of a protective film (not shown) is carried out. The protective film is cured by heating.

Next, the configuration of a conventional control unit will be described with reference to FIG. 6 showing a block diagram of the control unit. The conductive layer patterns 42 provided on the substrate 41 are individually connected to the LSI chip 51, and the clock line 52, the data line 53, the voltage line 54, and the ground line 55 are also connected to the LSI chip 51. The LSI chip 51 converts the data appearing on the data line 53 based on the continuous clock pulse supplied from the clock line 52 from
It is determined from which nozzle 32 the ink droplet should be ejected. Then, the LSI chip 51 applies the voltage V of the voltage line 54 to the pattern 42 of the conductive layer that is connected to the electrode 13 in the ink liquid chamber 12 for ejecting ink. Further, the LSI chip 51 applies the voltage 0 of the ground line 55 to the pattern 42 of the conductive layer that is electrically connected to the electrodes 13 other than the ink liquid chamber 12.

Next, the configuration and operation of the conventional example will be described with reference to FIG. 7 showing a perspective view of a printer. The ink ejection device 61 and the nozzle plate 31 have the configuration and operation described with reference to FIGS. 3, 4, 5, and 6. The ink ejection device 61 is fixed on a carriage 62, and the ink supply tube 63 communicates with the ink supply port 21 (FIG. 5).
The SI chip 51 (FIG. 6) is built in the carriage 62,
The flexible cable 64 corresponds to the clock line 52, the data line 53, the voltage line 54, and the ground line 55 shown in FIG. The carriage 62 reciprocates along the slider 66 in the direction of the arrow 65 over the entire width of the recording paper 71, and the ink ejecting device 61 moves the nozzle against the recording paper 71 held by the platen roller 72 while the carriage 62 is moving. Ink droplets are ejected from nozzles 32 (FIG. 5) provided on the plate 31 to adhere the ink droplets onto the recording paper 71.

The recording paper 71 is stationary when the ink ejecting device 61 ejects ink droplets. However, each time the carriage 62 reciprocates, the recording paper 71 is moved in the direction of arrow 75 by the paper feed rollers 73 and 74. It is transferred by a fixed amount. Thus, the ink ejecting apparatus 61 can form desired characters and images on the entire surface of the recording paper 71.

[0015]

However, in the above prior art, the electrodes 13 are required on both surfaces from the upper portion to the central portion of the side wall 11. When the electrode 13 is formed by vacuum deposition or sputtering, an electrode-forming substance such as aluminum or nickel is blown from obliquely above the side wall 11 and the lower portion of the surface of the side wall 11 is shaded by the adjacent side wall 11 to form a side wall. No electrode was formed below 11. Since the electrode forming material evaporated from the evaporation source flies in a radial direction, the straightness of the evaporation material is used to deposit on the side wall 11 using only a part of the electrode forming material evaporated from the evaporation source. In this case, it is necessary to increase the distance between the evaporation source and the side wall 11 on which the electrode 13 is formed, and there is a problem that the formation speed of the electrode 13 is low. Also, due to variations in the thickness of the side wall 11 and chipping of the upper corner, etc.,
The area of the surface of the side wall 11 where the electrode 13 is formed changes,
The amount of deformation of the side wall 11 varies, and the
2, the speed of the ink droplets fluctuates due to a change in the pressure of the ink in the ink jet head 2, and it is not easy to secure the yield and reliability of the ink ejecting device 61.

In the case of the plating method, in which the process is simpler and the equipment is cheaper than vacuum evaporation or sputtering, the electrode 13 is formed on the side wall 1.
Although it is necessary to cover only the lower part of the side wall 11 so as not to be formed at the lower part of the groove 1, it is difficult to cover only the lower part of the side wall 11 because the width of the groove is narrow. For this reason, it was difficult to form the electrodes 13 only on both surfaces from the upper portion to the central portion of the side wall 11 by plating.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a highly reliable ink jet apparatus in which electrodes can be easily formed and a method of manufacturing the same.

[0018]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an ink ejecting apparatus comprising: a wall formed of polarized piezoelectric ceramics; and an ink partially formed by the wall. a liquid chamber, which is formed on the whole surface of the ink chamber surface to become whole surface and the opposite side of the wall
An electrode, and an electrode for generating an electric field perpendicular to the polarization direction of <br/> the wall Niso by applying a voltage between the electrodes, the wall between the electrodes, the polarization direction Substantially in parallel with the ink liquid chamber up to a part of the depth direction of the ink liquid chamber, and the electric field is applied to the wall even when a voltage is applied between the electrodes.
And a groove-shaped portion for preventing the occurrence of pits.

According to a second aspect of the present invention, in the ink ejecting apparatus according to the first aspect, the groove portion is formed to substantially the center in the depth direction of the ink liquid chamber.

According to a third aspect of the present invention, there is provided an ink jet apparatus comprising: a plurality of walls formed of polarized piezoelectric ceramics; an ink liquid chamber formed between the walls; Electrode formed over the entire surface
Te, the electrode for generating an electric field perpendicular to the polarization direction of the wall Niso <br/> by applying a voltage between the electrodes, their
A groove formed in the wall between the electrodes to a part of a depth direction of the ink liquid chamber substantially in parallel with the polarization direction.
Part, and even if a voltage is applied between the electrodes,
Air to prevent the generation of the electric field, or
A non-conductive material having a relative dielectric constant smaller than that of the piezoelectric ceramic.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an ink ejecting apparatus, wherein a groove serving as an ink liquid chamber and a wall separating the groove are formed on the polarized piezoelectric ceramics, and an electrode is formed on the entire surface in the groove. After the electrodes are formed, the wall is divided substantially parallel to the polarization direction from the zenith of the wall to a predetermined depth, and a voltage is applied to the wall even if a voltage is applied between the electrodes.
A dividing groove for preventing generation of the electric field is formed.

According to a fifth aspect of the present invention, in the method of the fourth aspect , the electrode is formed by a plating method.

[0023]

In the ink jetting apparatus of the present invention having the above-described structure, the wall formed of the polarized piezoelectric ceramics constitutes a part of the ink chamber, and the entire surface of the wall which is the ink liquid chamber inner surface and Electrodes formed on the entire surface on the opposite side generate an electric field orthogonal to the polarization direction of the wall. The groove formed in the inside prevents the electric field from being generated on the wall of the region corresponding to the groove forming portion, generates an electric field only in the portion where the groove is not formed, deforms the wall, and causes the ink liquid chamber to deform. Is ejected from the ink.

In the manufacturing method, after the electrodes are formed, a dividing groove for dividing the wall from the zenith of the wall to a predetermined depth is formed.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The same members as those in the related art are denoted by the same reference numerals, and description thereof will be omitted.

First, FIG. 1 is a cross-sectional view of an ink ejecting apparatus.
The configuration of one embodiment of the present invention will be specifically described. As shown in FIG.
Is a plurality of grooves 115 and side walls 111 separating the grooves 115
have. On the side wall 111, a dividing groove 16 is formed as a groove-like portion. The dividing groove 116 is formed on the side wall 1.
11 is the depth from the zenith to the center. Also, the side wall 1
Reference numeral 11 denotes a polarization process in the direction of arrow 4. Groove 11
An electrode 113 made of a conductive material such as aluminum, nickel, or gold is provided on the entire surface of the inside 5 and the top of the side wall 111.
Are formed by chemical plating, sputtering, vacuum evaporation, or the like. Here, after the electrode 113 is formed, the dividing groove 116 is formed, and the electrode at the zenith of the side wall 111 is separated left and right. Next, the piezoelectric ceramic plate 1
And a cover plate 2 made of a ceramic material or a resin material or the like, and a bonding layer 3 made of an epoxy-based adhesive or the like.
To join. Thus, the groove 115 becomes a plurality of ink liquid chambers 112 which are spaced apart from each other in the horizontal direction. The ink liquid chamber 112 has an elongated shape with a rectangular cross section,
Extends over the entire length of the ink liquid chamber 112. The ink liquid chamber 112 is filled with ink, and the dividing groove 116 is filled with air.

Next, FIG. 2 is a sectional view of the ink ejecting apparatus.
Hereinafter, the operation of the embodiment of the present invention will be specifically described. In the ink ejecting apparatus, for example, when the ink liquid chamber 112b is selected according to desired print data, the electrode 1
13c rapidly applies a negative drive voltage to the electrode 113b.
And 113d are grounded. Here, at the upper part of the side wall 111 where the dividing grooves 116 of the side walls 111b and 111c are formed, the relative dielectric constant of the air filled in the dividing grooves 116 is very small as compared with the piezoelectric ceramics. Has little effect. As a result, a driving electric field in the direction of arrow 114b acts only on the lower portion of side wall 111b, and a driving electric field in the direction of arrow 114c acts on only the lower portion of side wall 111c. Driving electric field directions 114b and 11
4c and the polarization direction 4 are orthogonal to each other, so that the side wall 111b
And 111c are rapidly deformed toward the inside of the ink liquid chamber 112b due to the piezoelectric thickness-shear effect. Due to this deformation, the volume of the ink liquid chamber 112b decreases, and
The ink pressure in the ink liquid chamber 112b is rapidly increased, and a pressure wave is generated. The nozzle 32 communicates with the ink liquid chamber 112b (FIG. 5).
Ejects ink droplets.

When the application of the driving voltage is stopped, the side walls 111b and 111c return to the positions before deformation (see FIG. 1), so that the ink pressure in the ink liquid chamber 112b decreases, and the ink supply port 21 (see FIG. 5). ) Is supplied to the ink chamber 112b through the manifold 22 (see FIG. 5).

In the ink jetting apparatus of this embodiment, the side wall 11
Since the electrode 113 may be formed on the entire side surface of the first side, the electrode 113 can be easily formed by plating. In this case, it is not necessary to install the piezoelectric ceramic plate 1 in a vacuum for processing, so that a large capital investment for vacuuming is not required, and the piezoelectric ceramic plate 1 that can be processed at one time by enlarging the plating tank is not required. Can be increased, and the cost of the ink ejecting apparatus can be significantly reduced.

When the electrode 113 is formed by sputtering or vacuum evaporation, the distance between the evaporation source and the piezoelectric ceramic plate 1 can be shortened.
The electrode forming substance evaporated from the evaporation source can be effectively used, the formation speed of the electrode 113 is increased, and the number per time is increased. Further, the electrode 113 is formed in the groove 1 without being affected by variations in the thickness of the side wall 111 or chipping of the upper corner.
15, the pressure of the ink in the ink liquid chamber 112 does not change due to a change in the surface area of the side wall 111 where the electrode 113 is formed. It is easy to ensure reliability.

Further, since the dividing groove 116 is formed after the electrode 113 is formed, the electrode at the zenith of the side wall 111 is separated left and right, so that the step of removing the electrode at the zenith as in the conventional case is unnecessary. It is.

In the above-described embodiment, when, for example, the ink liquid chamber 112b is selected according to desired print data, a negative drive voltage is rapidly applied to the electrode 113c, and the electrodes 113b and 113d are grounded. , Electrode 11
A positive drive voltage may be rapidly applied to 3b and 113d, and the electrode 113c may be grounded.

In the above-described embodiment, first, a drive voltage is applied in a direction in which the volume of the ink liquid chamber 112b decreases, thereby ejecting ink droplets. Increase the volume of the ink liquid chamber 112
b, ink is supplied into the ink liquid chamber 112 by applying a drive voltage in a direction in which the volume of the ink liquid chamber 112 increases, and then the application of the drive voltage is stopped to stop the ink supply. The ink droplets may be ejected by reducing the volume of the liquid chamber 112.

In the above embodiment, the dividing groove 11
Although the air is filled in the inside of the piezoelectric ceramic plate 6, it may be filled with a non-conductive material such as ink, resin, ceramics, etc., whose relative dielectric constant is 1/10 or less of that of the piezoelectric ceramic plate 1.

In the above embodiment, the electrode 113 is formed on the entire surface inside the groove 115.
There may be a region in which no electrode 113 is formed, for example, the electrode 113 may not be formed on the bottom surface of the groove 115.

The electrode at the top of the side wall 111 may be removed.

[0037]

As is apparent from the above description, according to the ink jetting apparatus of the present invention, the groove is formed substantially parallel to the polarization direction of the wall to a part of the depth of the ink liquid chamber in the depth direction. Since the groove is provided, the groove does not generate the electric field on the wall of the groove forming portion, the electric field is generated only on the portion of the wall where the groove is not formed, and the wall is deformed to form the ink liquid chamber. Eject ink from the For this reason, since the electrode can be provided on the entire surface of the wall, the electrode can be easily formed, and is not affected by variations in wall thickness and chipping of the upper corner as in the conventional case. In addition, the yield and reliability of the ink ejecting device can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an ink ejecting apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a conventional ink ejecting apparatus.

FIG. 4 is an explanatory diagram showing the operation of a conventional ink ejecting apparatus.

FIG. 5 is a perspective view showing a conventional ink ejecting apparatus.

FIG. 6 is a block diagram showing a control unit of a conventional example.

FIG. 7 is a perspective view showing a conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric ceramic plate 2 Cover plate 111 Side wall 112 Ink liquid chamber 113 Electrode 115 Groove 116 Dividing groove

Claims (5)

(57) [Claims] 1. A wall formed of polarized piezoelectric ceramics; an ink liquid chamber partially formed by the wall; and an entire surface of the wall which is the inner surface of the ink liquid chamber and an entire surface on the opposite side thereof Electrodes formed between the electrodes
And electrodes for generating an electric field perpendicular to the polarization direction of the wall Niso by applying pressure, into the wall between the electrodes, the polarized direction substantially parallel to the depth direction of the ink chamber Is provided to some depth of the front
The electric field is generated on the wall even when a voltage is applied between the electrodes.
And a groove portion for preventing the ink jetting from occurring. 2. The ink ejecting apparatus according to claim 1, wherein the groove-shaped portion is formed to substantially the center in the depth direction of the ink liquid chamber. 3. A plurality of walls formed of polarized piezoelectric ceramics; an ink liquid chamber formed between the walls; and both surfaces of the wall are formed over the entire surface in the depth direction of the ink liquid chamber . Electrodes, and voltage is applied between the electrodes
Wherein the electrodes for generating an electric field perpendicular to the polarization direction of the wall Niso, the wall between the electrodes, the polarized direction substantially parallel to a portion of the depth direction of the ink chamber by Grooves formed to a depth of
The wall is filled even if a voltage is applied between the electrodes.
An ink ejecting apparatus comprising: air for preventing generation of the electric field or a non-conductive material having a relative dielectric constant smaller than that of the piezoelectric ceramic. 4. A groove serving as an ink liquid chamber and a wall separating the groove are formed on the polarized piezoelectric ceramics. An electrode is formed on the entire surface in the groove. substantially parallel, divides the wall from the top portion of the wall to a predetermined depth, said collector
Even if a voltage is applied between the electrodes of the electric field to the wall to occur
Forming a dividing groove for preventing ink jetting. 5. The method according to claim 4 , wherein the electrode is formed by a plating method.