JP3255316B2 - Ink jet device - 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.

[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. Hereinafter, the configuration of the conventional example will be specifically described with reference to FIG. 3 showing a cross-sectional view of the ink ejecting apparatus. A plurality of grooves 15 and side walls 1 separating the grooves 15
1 and a cover plate 2 made of a ceramic material, a resin material, or the like, which is polarized in a direction of an arrow 4 and a cover plate 2 made of a ceramic material or a resin material, via a bonding layer 3 made of an epoxy-based adhesive or the like. By doing, the groove 15
Are a plurality of ink liquid chambers 12 spaced from each other in the horizontal direction. The ink liquid 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 1 for applying a driving electric field are provided on both surfaces from the top of the side wall 11 near the adhesive layer 3 to the center of the side wall 11.
3 are formed. All the ink liquid chambers 12 are filled with ink.

FIG. 4 is a cross-sectional view of an 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 drive voltage is gradually stopped, the side walls 11b and 11c return to the positions before deformation (see FIG. 3), so that the ink pressure in the ink liquid chamber 12b gradually decreases, and the ink supply port 21 (FIG. ) To manifold 22 (FIG. 5)
The ink is supplied into the ink liquid chamber 12b through the ink passage.

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 merely a basic operation of the conventional example, and when embodied as a product, first, a drive voltage is 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 is 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 formed so as to gradually become shallower as approaching the end face 17 and become a shallow parallel groove 18 near the end face 17. The electrodes 13 are formed on the inner surfaces of the groove 15 and the shallow parallel groove 18 by sputtering or the like. On the inner surface of the groove 15, the electrode 13 is formed only on the upper half of the side surface. On the inner surface of the shallow and parallel groove 18, the electrode 13 is formed on the entire side surface and bottom surface. Further, the ink inlet 21 and the 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 bonded to each other with an epoxy-based adhesive or the like such that each groove 15 forms the ink liquid chamber 12 having the above-described shape. Next, the nozzle plate 3 provided with the nozzle 32 at a position corresponding to the position of each ink liquid chamber 12 on the end face 16 of the piezoelectric ceramic plate 1 and the cover plate 2.
1 is adhered. A substrate 41 provided with a conductive layer pattern 42 at a position corresponding to the position of each ink liquid chamber 12 on the surface of the piezoelectric ceramic plate 1 opposite to the groove 15 processing side.
Are bonded with an epoxy adhesive or the like. Then, the electrode 13 and the conductive layer pattern 4 on the bottom of the shallow parallel groove 18 are formed.
2 are connected by a conductive wire 43 by wire bonding.

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, and the voltage V of the voltage line 54 is applied to the conductive layer pattern 42 that is connected to the electrode 13 in the ink chamber 12 to be driven. Further, a voltage 0 of the ground line 55 is applied to the conductive layer pattern 42 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, and 5. The ink ejection device 61 is fixed on a carriage 62, the ink supply tube 63 communicates with the ink supply port 21 (FIG. 5), the LSI chip 51 (FIG. 6) is built in the carriage 62, and the flexible cable 64 is Clock line 5 shown
2, corresponding to the data line 53, the voltage line 54 and the ground line 55. The carriage 62 is a slider 66
Reciprocates along the entire width of the recording paper 71 in the direction of arrow 65 along the arrow, and the ink ejecting device 61 moves the recording paper 7 held by the platen roller 72 while the carriage 62 is moving.
Nozzle 3 provided on nozzle plate 31
2 (FIG. 5), the ink droplets are ejected, and the ink droplets are deposited on the recording paper 71.

The recording paper 71 is stationary when the ink ejecting device 61 ejects ink droplets, but each time the carriage 62 reciprocates, it 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.

[0012]

However, in the above-described conventional ink ejecting apparatus 61, the electrodes 13 are formed so as to be exposed on the inner surface of the ink liquid chamber 12, and come into contact with the ink inside the ink liquid chamber 12. As a result, the electrode 13 is corroded by moisture contained in the ink. For this reason, there is a problem that the deformation amount of the side wall 11 is reduced, the voltage is not transmitted to a part of the side wall 11 due to the disconnection of the electrode 13 and the part of the side wall 11 is not deformed, and the injection becomes unstable. there were. Therefore, there is a problem that the reliability of the ink ejecting apparatus is low.

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 having a long electrode life.

[0014]

In order to achieve this object, according to the first aspect of the present invention, at least a part is formed between a plurality of side walls composed of a piezoelectric portion , and a nozzle for ejecting ink droplets is provided.
A plurality of ink chambers through nozzle and communicating, a outer surface of said ink chamber, said perpendicular to the arrangement direction of the ink chamber
Formed facing the part corresponding to both ends in the height direction of the side wall
And at least one of them corresponds to each side wall.
Electrodes that generate an electric field in the height direction of the plurality of side walls, and selectively apply a voltage between the electrodes.
With this, an electric field is generated in the height direction of the side wall, and the
Deforming the side wall with respect to the ink liquid chamber,
An ink droplet is ejected from the nozzle communicating with the chamber .

According to a second aspect, the polarization direction of the piezoelectric portion is
The direction of the electric field generated from the electrode is substantially orthogonal to the direction of the electric field.

According to claim 3, the side wall has a height of the side wall.
A plurality of layers in the direction , at least one layer is the piezoelectric portion, and the electrodes are at least both ends in the height direction of the side wall.
Characterized that you located portion corresponding to the section.

According to a fourth aspect of the present invention, the two layers on the side wall are the piezoelectric portions, and the polarization directions of the two layers are opposite to each other.

[0018] According to claim 5, before Symbol sidewalls and an ink liquid chamber is formed on one surface of the piezoelectric ceramic plate,
The electrode has a side wall of the piezoelectric ceramic plate and
The ink liquid chamber is formed on a surface opposite to the one surface on which the ink liquid chamber is formed.

[0019]

In the present invention having the above structure, at least a portion is formed between the plurality of side walls composed of the piezoelectric portion , and the ink liquid is formed.
A plurality of ink liquid chambers communicating with a nozzle for ejecting droplets, and an outer surface of the ink liquid chamber, wherein at least the ink liquid chamber
At both ends in the height direction of the side wall orthogonal to the arrangement direction of the
And at least one of them
Are formed corresponding to each side wall, and an electric field is generated in the height direction of the side wall.
And an electrode for generating a voltage, and applying a voltage between the electrodes.
As a result, an electric field is generated in the height direction of the side wall ,
Deforming the side wall with respect to the ink liquid chamber;
Order to eject ink droplets from the nozzle communicating with the liquid chamber, the electrode does not come in contact with the ink inside the ink chamber. As a result, the electrodes are not corroded by moisture contained in the ink, and the ejection is not unstable.
The life of the electrode can be prolonged, and the reliability can be increased.

[0020]

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 sectional view showing an ink ejecting apparatus.
The configuration of one embodiment of the present invention will be specifically described. As shown in FIG. 1, a groove 123 is formed on one surface of the piezoelectric ceramic plate 101 that has been subjected to polarization processing in the direction of the arrow 141 by grinding using a thin disk-shaped diamond blade or the like. Also, the piezoelectric ceramic plate 10 that has been subjected to polarization processing in the direction of arrow 142
The groove 124 is similarly formed on one surface of No. 2. Next, the surface of the piezoelectric ceramic plate 101 on which the groove 123 is formed and the surface of the piezoelectric ceramic plate 102 on which the groove 124 is formed are joined to the bonding layer 11 made of an epoxy-based adhesive or the like.
1 are joined. Thus, the plurality of grooves 123, 12
Reference numeral 4 denotes a plurality of ink liquid chambers 122 which are spaced apart from each other in the lateral direction by the side walls 121. The ink liquid chamber 122 has an elongated shape with a rectangular cross section, and the side wall 121 extends over the entire length of the ink liquid chamber 122.

Next, at a position corresponding to the position of the side wall 121 on the surface of the piezoelectric ceramic plate 101 opposite to the surface on which the groove 123 is formed, a metal such as aluminum, nickel, gold, or a conductive resin is formed. Electrode 131 is vacuum deposited,
It is formed by sputtering, chemical plating, or the like. Similarly, aluminum, nickel, and the like are formed on the entire surface of the piezoelectric ceramic plate 102 opposite to the surface on which the groove 124 is formed.
An electrode 132 made of a metal such as gold or a conductive resin is formed by vacuum deposition, sputtering, chemical plating, or the like. All the ink liquid chambers 122 are filled with ink.

Next, FIG. 2 is a sectional view of the ink ejecting apparatus.
The operation of one embodiment of the present invention will now be described. In the ink ejecting apparatus, for example, when the ink liquid chamber 122b is selected according to desired print data, a negative driving voltage is rapidly applied to the electrode 131b, and a positive driving voltage is rapidly applied to the electrode 131c. The electrode 132 is grounded. Thus, a driving electric field in the direction of arrow 151b acts on the side wall 121b, and a driving electric field in the direction of arrow 151c acts on the side wall 121c. At this time, since the driving electric field directions 151b and 151c are orthogonal to the polarization directions 141 and 142, the side walls 121b and 121c are rapidly deformed toward the inside of the ink liquid chamber 122b due to the piezoelectric thickness-shear effect. Due to this deformation, the volume of the ink liquid chamber 122b decreases, the ink pressure in the ink liquid chamber 122b rapidly increases, a pressure wave is generated, and the ink droplets from the nozzle 32 (FIG. 5) communicating with the ink liquid chamber 122b. Is injected.

When the application of the driving voltage is stopped, the side walls 121b and 121c return to the positions before the deformation (see FIG. 1), so that the ink pressure in the ink liquid chamber 122b decreases and the ink supply port 21 (FIG. 5) To manifold 22 (Fig. 5)
Is supplied to the ink liquid chamber 122b through the ink passage.

In the ink jetting apparatus of this embodiment, the electrodes 13
1 and 132 do not contact the ink inside the ink liquid chamber 122. Therefore, the electrodes 131 and 132 are not corroded by moisture or the like contained in the ink, and ejection is not unstable. Therefore, it is possible to provide a highly reliable ink ejecting apparatus having a long electrode life.

In the above embodiment, the electrode 132 common to all the side walls 121 is provided on the surface of the piezoelectric ceramic plate 102 opposite to the surface on which the groove 124 is formed. Like the electrode 131, it may be provided separately at a position corresponding to the position of the side wall 121.

Further, in the above embodiment, the side wall 121 is formed.
Is formed of the piezoelectric ceramic plate 101 and the piezoelectric ceramic plate 102, one of which may be made of a material other than the piezoelectric material, for example, ceramics or resin.

In the above embodiment, first, a drive voltage is applied in a direction in which the volume of the ink liquid chamber is reduced to eject ink droplets, and then the application of the drive voltage is stopped to reduce the volume of the ink liquid chamber. Although the ink was supplied to the ink liquid chamber by increasing it, first, a drive voltage was applied in a direction to increase the volume of the ink liquid chamber to supply the ink to the ink liquid chamber, and then the application of the drive voltage was stopped. The ink droplets may be ejected by reducing the volume of the ink liquid chamber.

[0029]

As is apparent from the above description, according to the present invention, a plurality of ink liquid chambers formed at least in part between a plurality of side walls composed of piezoelectric portions and communicating with nozzles for ejecting ink droplets. And the outer surface of the ink liquid chamber ,
The height direction of the side wall perpendicular to the arrangement direction of the ink liquid chambers
While being formed facing parts corresponding to both ends,
At least one of them is formed corresponding to each side wall.
And an electrode for generating an electric field in the height direction of the side wall of the few, before
By selectively applying a voltage between the electrodes,
An electric field is generated in the height direction of the wall, and the ink is applied to the side wall by the ink.
The liquid chamber is deformed and communicates with the ink liquid chamber.
Since the ink droplets are ejected from the nozzles , the electrodes do not come into contact with the ink inside the ink liquid chamber. For this reason, the electrodes are not corroded by moisture or the like contained in the ink,
Injection does not become unstable. For this reason, it is possible to provide an ink ejection device in which the life of the electrode is long and the reliability is high.

[Brief description of the drawings]

FIG. 1 is a sectional view of 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 sectional view of 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 of a conventional ink ejecting apparatus.

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

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

[Explanation of symbols]

 32 ejection nozzle 111 side wall 112 ink liquid chamber 131 electrode 132 electrode

Claims (5)

(57) [Claims] 1. A method according to claim 1, wherein at least a portion is formed between a plurality of side walls formed of a piezoelectric portion and is connected to a nozzle for ejecting ink droplets.
A plurality of ink liquid chambers that have passed through , and an outer surface of the ink liquid chamber, the arrangement of the ink liquid chambers.
Corresponding to both ends in the height direction of the side wall orthogonal to the direction
And at least one of them
Are formed corresponding to each side wall, and the height direction of the plurality of side walls is
And an electrode for generating an electric field , selectively between the electrodes.
An electric field is applied in the height direction of the side wall by applying a voltage.
And the side wall is deformed with respect to the ink liquid chamber.
The ink liquid from the nozzle communicating with the ink liquid chamber.
An ink ejecting apparatus, which ejects droplets . 2. The ink ejecting apparatus according to claim 1, wherein the direction of polarization of the piezoelectric portion is substantially orthogonal to the direction of an electric field generated from the electrode. Wherein the side wall includes a plurality layers in the height direction of the side wall, at least more that the piezoelectric unit, wherein
The electrodes correspond at least to both ends in the height direction of the side wall.
The ink jet apparatus according to claim 2 wherein the position to said Rukoto the moiety. 4. The piezoelectric unit according to claim 2, wherein the two layers of the side wall are the piezoelectric unit,
4. The ink jet apparatus according to claim 3, wherein the polarization directions of the two layers are opposite to each other. Wherein said side walls and an ink liquid chamber is formed on one surface of the piezoelectric ceramic plate, wherein the electrode,
2. The ink ejecting apparatus according to claim 1, wherein a side wall of the piezoelectric ceramic plate and a surface opposite to the one surface where the ink liquid chamber is formed are formed.