JPH06344550A - Ink jet device - Google Patents

Abstract

PURPOSE:To provide an ink jet device prolonged in the life of an electrode and enhanced in the reliability. CONSTITUTION:Electrodes 113, 114 composed of a metal such as aluminum, nickel or gold or a conductive resin are formed on both surfaces of a piezoelectric ceramics plate subjected to polarizing treatment in the direction shown by an arrow 106. Next, the surface having the electrode 114 formed thereon of the piezoelectric ceramics plate 101 and a base plate 102 are bonded through a bonding layer 104. Grooves 116 piercing the piezoelectric ceramics plate 101 to reach the base plate 102 are formed by grinding processing and the surface having the electrode 113 formed thereto of the piezoelectric ceramics plate 101 and a cover plate 103 are bonded through a bonding layer 105. By this method, a plurality of ink liquid chambers 112 partitioned by side walls 111 are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet device.

[0002]

2. Description of the Related Art Conventionally, as a printer head, a drop-on-demand type ink jet printer head applying piezoelectric ceramics has been proposed. This is because by changing the volume of the ink liquid chamber by the deformation of the piezoelectric ceramics, the ink in the ink liquid chamber is ejected as droplets from the nozzle when the volume is decreased, and when the volume is increased, the ink is injected from the other ink introduction path into the ink liquid chamber. The ink is introduced. Then, by arranging a large number of such ink liquid chambers close to each other and ejecting ink droplets from nozzles at desired positions according to desired print data, desired characters or characters can be printed on the paper surface facing the nozzles. It forms an image.

Examples of this type of ink ejecting device include, for example, Japanese Patent Laid-Open Nos. 63-247051 and 63-252.
750 and JP-A-2-150355. FIG. 6, FIG. 7, FIG. 8, FIG. 9 and FIG. 10 show schematic diagrams of these conventional examples. Hereinafter, the configuration of the conventional example will be specifically described with reference to FIG. 6 showing a cross-sectional view of the ink ejecting apparatus. A piezoelectric ceramic plate 1 having a plurality of grooves 15 (FIG. 8) and a side wall 11 separating the grooves 15 and polarized in the direction of the arrow 4, and a cover plate 2 made of a ceramic material, a resin material, or the like. The grooves 15 (FIG. 8) are formed into a plurality of ink liquid chambers 12 that are spaced from each other in the lateral direction by bonding the bonding layers 3 made of an epoxy adhesive or the like. 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 13 for applying a driving electric field are formed on both surfaces of the sidewall 11 near the adhesive layer 3 from the upper portion of the sidewall 11 to the central portion of the sidewall 11. Ink is filled in all the ink liquid chambers 12.

Next, FIG. 7 showing a sectional view of the ink ejecting apparatus.
The operation of the conventional example will be described below. 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, the driving electric field in the direction of arrow 14b acts on the side wall 11b, and the 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 are formed.
Is rapidly deformed inwardly of the ink liquid chamber 12b due to the piezoelectric thickness sliding 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, so that the ink liquid chamber 12b is generated.
Ink droplets are ejected from the nozzle 32 (FIG. 8) that communicates with. Further, when the application of the drive voltage is gradually stopped, the side walls 11b and 11c return to the positions before the deformation (see FIG. 6), so that the ink pressure in the ink liquid chamber 12b gradually decreases and the ink supply port 21 (see FIG. 8). ) To the manifold 22 (FIG. 8)
Ink is supplied into the ink liquid chamber 12b through the.

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

However, the above operation is only the basic operation of the conventional example, and when it is embodied as a product, first, a driving voltage is applied in the direction of increasing the volume, and then the ink liquid chamber 12b is first applied.
After the ink is supplied to the ink, the application of the drive voltage may be stopped and the ink may be ejected in the original state (see FIG. 6). .

Next, FIG. 8 showing a perspective view of the ink ejecting apparatus.
The configuration and manufacturing method of the conventional example will be described below. The parallel grooves 1 that form the ink liquid chamber 12 having the above-described 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 almost the entire area of the piezoelectric ceramic plate 1, but the groove 15 is gradually shallowed toward the end face 17, and is formed so as to be 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. The electrode 13 is formed only on the upper half of the side surface of the groove 15, whereas the electrode 13 is formed on the entire side surface and bottom surface of the shallow parallel inner surface of the groove 18. In addition, the ink inlet 21 and the manifold 22 are formed in the cover plate 2 made of a ceramic material or a resin material by grinding or cutting.

Next, the groove 1 of the piezoelectric ceramic plate 1
The surface of the cover plate 2 on the processing side and the surface of the cover plate 2 on the processing side of the manifold 22 are adhered by an epoxy adhesive or the like so that each groove 15 forms the ink liquid chamber 12 having the above-described shape. Next, on the end faces 16 of the piezoelectric ceramic plate 1 and the cover plate 2, the nozzle plate 3 is provided with nozzles 32 at positions corresponding to the positions of the respective ink liquid chambers 12.
Glue 1 A substrate 41 on which a pattern 42 of a conductive layer is provided on the surface of the piezoelectric ceramic plate 1 opposite to the groove 15 processing side at a position corresponding to the position of each ink liquid chamber 12.
Are bonded with an epoxy adhesive or the like. Then, the electrode 13 on the bottom surface of the shallow parallel groove 18 and the pattern 4 of the conductive layer are formed.
2 and 2 are connected by a conductor 43 by a well-known wire bonding.

Next, the configuration of the conventional control unit will be described with reference to FIG. 9 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. Based on the continuous clock pulse supplied from the clock line 52, the LSI chip 51 determines from the data appearing on the data line 53
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 pattern 42 of the conductive layer which is electrically connected to the electrode 13 in the driven ink liquid chamber 12. Further, the voltage 0 of the earth line 55 is applied to the pattern 42 of the conductive layer which is electrically connected to the electrodes 13 other than the ink liquid chamber 12.

Next, the construction and operation of the conventional example will be described with reference to FIG. 10 showing a perspective view of the printer. The ink ejecting device 61 and the nozzle plate 31 are similar to those shown in FIGS.
It has the configuration and operation described in.

The ink ejecting device 61 is fixed on the carriage 62, and the ink supply tube 63 is connected to the ink supply port 21.
(FIG. 8), the LSI chip 51 (FIG. 9) is built in the carriage 62, and the flexible cable 64 is shown in FIG.
It 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 arrow 65 over the entire width of the recording paper 71, and the ink ejecting device 6
A nozzle 1 (FIG. 8) provided in the nozzle plate 31 ejects ink droplets onto the recording paper 71 held by the platen roller 72 while the carriage 62 is moving, and Apply ink drops.

Although the recording paper 71 is stationary when the ink ejecting device 61 ejects ink droplets, the recording paper 71 is moved in the direction of arrow 75 by the paper feed rollers 73 and 74 each time the carriage 62 reciprocates. It is transferred by a fixed amount. As a result, the ink ejecting device 61 can form a desired character or image on the entire surface of the recording paper 71.

[0013]

However, in the conventional ink ejecting apparatus 61 as described above, the electrode 13 is formed so as to be exposed on the inner surface of the ink liquid chamber 12, and thus the ink liquid chamber 12 is formed.
Since it contacts the ink inside, the electrode 13 is corroded by the moisture contained in the ink. Therefore, the side wall 11
Of the side wall 1
There is a problem that the voltage is not transmitted to a part of No. 1 and the part of the side wall 11 is not deformed, and the injection becomes unstable. Therefore, there is a problem that the reliability of the ink ejecting apparatus is low.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an ink ejecting apparatus having a long electrode life and high reliability.

[0015]

In order to achieve this object, according to the present invention, an ink liquid chamber filled with ink and a piezoelectric portion at least a part of which is separated from the ink liquid chamber are formed. An ink ejecting apparatus having a side wall and an electrode formed on the piezoelectric portion, wherein the side wall is deformed by applying a voltage to the electrode to apply pressure to the ink in the ink liquid chamber to eject the ink. The surface of the voltage section on which the electrode is formed is different from the inner surface of the ink liquid chamber, and the direction of the electric field generated by application to the electrode is substantially orthogonal to the polarization direction of the piezoelectric section, and The deformation direction is substantially parallel to the polarization direction of the piezoelectric portion.

[0016]

In the ink jet apparatus of the present invention having the above structure, the surface of the voltage portion on which the electrode is formed is different from the inner surface of the ink liquid chamber, and the direction of the electric field generated by application to the electrode is the piezoelectric element. Since the deformation direction of the side wall is substantially orthogonal to the polarization direction of the piezoelectric portion and the deformation direction of the side wall is substantially parallel to the polarization direction of the piezoelectric portion, the electrode hardly contacts the ink in the ink liquid chamber.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same members as those of the conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

First, the construction of an embodiment of the present invention will be specifically described with reference to FIG. 1 showing a sectional view of an ink ejecting apparatus in the process of manufacturing and FIG. 2 showing a sectional view of a completed ink ejecting apparatus. As shown in FIG. 1, on both surfaces of the piezoelectric ceramic plate 101 that has been polarized in the direction of arrow 106,
The electrodes 113 and 114 made of a metal such as aluminum, nickel or gold or a conductive resin are formed by vacuum vapor deposition, sputtering, chemical plating or the like. Next, the surface of the piezoelectric ceramic plate 101 on which the electrode 114 is formed and the base plate 1 made of a ceramic material, a resin material, or the like.
02 is bonded to each other via a bonding layer 104 made of an epoxy adhesive or the like.

Next, as shown in FIG. 2, a groove 116 penetrating the piezoelectric ceramic plate 101 and reaching the base plate 102 is formed by grinding or the like using a thin disk-shaped diamond blade. After that, the surface of the piezoelectric ceramic plate 101 on which the electrode 113 is formed and the cover plate 103 made of a ceramic material, a resin material, or the like are joined via a joining layer 105 made of an epoxy adhesive or the like. This has a plurality of grooves 116 and side walls 111 separating the grooves 116, and
Is a plurality of ink chambers 112 that are laterally spaced from each other.
Becomes The ink liquid chamber 112 has an elongated shape with a rectangular cross section, and the side wall 111 extends over the entire length of the ink liquid chamber 112. Ink is filled in all the ink liquid chambers 112.

Next, FIG. 3 showing a sectional view of the ink ejecting apparatus.
The operation of the embodiment of the present invention will be described below.

In the ink ejecting apparatus, when the ink liquid chamber 112b is selected according to desired print data, a positive drive voltage is rapidly applied to the electrodes 113b and 114c, and the electrodes 113c and 114b are grounded. As a result, the driving electric field in the direction of arrow 115b acts on the side wall 111b, and the driving electric field in the direction of arrow 115c acts on the side wall 111c. At this time, the driving electric field directions 115b and 115c
And the polarization direction 106 are orthogonal to each other, the side wall 111b
And 111c are rapidly deformed toward the inside of the ink liquid chamber 112b due to the piezoelectric thickness sliding effect. Due to this deformation, the volume of the ink liquid chamber 112b decreases and the ink liquid chamber 1
The ink pressure in 12b rapidly increases, a pressure wave is generated, and ink droplets are ejected from the nozzle 32 (see FIG. 8) communicating with the ink liquid chamber 112b.

Further, when the application of the drive voltage is gradually stopped, the side walls 111b and 111c return to the positions before the deformation (see FIG. 2), so that the ink pressure in the ink liquid chamber 112b gradually decreases, and the ink supply port 21. Ink is supplied from the ink chamber 112b (see FIG. 8) through the manifold 22 (see FIG. 8).

As described above, in the ink jet apparatus of this embodiment, the direction of the electric field generated by the application to the electrodes 113b and 114c is orthogonal to the polarization direction 106 of the piezoelectric ceramic plate 101, and the side walls 111b and 111c are deformed. Is the polarization direction 10 of the piezoelectric ceramic plate 101.
It is configured to be substantially parallel to 6. That is, the electrode 113 is formed between the piezoelectric ceramic plate 101 and the bonding layer 105, and the electrode 114 is formed between the piezoelectric ceramic plate 101 and the bonding layer 104.
For this reason, most of the electrodes 113 and 114 do not come into contact with the ink inside the ink liquid chamber 112, and the electrode 1
The 13 and 114 are not corroded by the water contained in the ink and the like, and the unstable ejection is prevented. Therefore, it is possible to provide a highly reliable ink jet device in which the electrodes 113 and 114 have a long life.

In the above embodiment, the electrode 113b is used.
And 114c were applied with a positive drive voltage, and electrodes 113c and 114b were grounded.
May be grounded and a negative drive voltage may be applied to the electrodes 113c and 114b, or a positive drive voltage may be applied to the electrodes 113b and 114c and a negative drive voltage may be applied to the electrodes 113c and 114b. In any case, the driving electric field in the direction of arrow 115b acts on the side wall 111b, and the driving electric field in the direction of arrow 115c acts on the side wall 111c, as in the above-described embodiment.

In the above embodiment, first, the driving voltage is applied in the direction in which the volume of the ink liquid chamber 12 is reduced to eject ink droplets, and then the application of the driving voltage is stopped and the ink liquid chamber 12 is discharged. Ink was supplied into the ink liquid chamber 12 with the volume set to a natural state.
Ink is supplied to the inside of the ink liquid chamber 12 by applying it in the direction of increasing the volume of the ink liquid, and then the application of the drive voltage is stopped to decrease the volume of the ink liquid chamber 12 from the increasing state to the natural state. Droplets may be ejected.

Further, in the above embodiment, the side wall 111
Although only the upper half of the side wall is made of a piezoelectric material, the entire side wall may be made of a piezoelectric material. As shown in FIG. 4, on the side wall 211, the piezoelectric ceramic plate 201 polarized in the direction of arrow 208 and the piezoelectric ceramic plate 202 polarized in the direction of arrow 209 are bonded via a bonding layer 207. An electrode 213 is formed on the upper surface of the piezoelectric ceramic plate 201, and an electrode 214 is formed on the lower surface of the piezoelectric ceramic plate 202. The upper portion of the side wall 211 is joined to the cover plate 204 via the joining layer 205, and the lower portion of the side wall 211 is joined to the joining layer 2.
It is joined to the base plate 203 via 06.

When, for example, the ink liquid chamber 212b is selected in accordance with the desired print data in the ink ejecting apparatus, a positive drive voltage is rapidly applied to the electrodes 213c and 214b, the electrodes 213b and 214c are grounded, and then driven. The voltage application is stopped. Thereby, the ink liquid chamber 212b
The ink droplets are ejected and the ink is supplied into the ink liquid chamber 212b.

Further, in the above embodiment, the piezoelectric ceramic plate 101 and the cover plate 103 are bonded to each other via the bonding layer 105, but the cover plate and the piezoelectric ceramic plate may be integrated. Figure 5
As shown in FIG. 3, the piezoelectric ceramic plate 301 is polarized in the direction of arrow 304, and an electrode 313,
A groove 315 and an electrode 314 that form a part of the ink liquid chamber 312 are formed on the lower surface. Further, the lower surface of the piezoelectric ceramic plate 301 is bonded to the base plate 302 having the groove 315 forming a part of the ink liquid chamber 312 formed on the upper surface thereof via the bonding layer 303.

When, for example, the ink liquid chamber 312b is selected in accordance with desired print data in the ink ejecting apparatus, a positive driving voltage is rapidly applied to the electrode 314b and a negative driving voltage is applied to the electrode 314c while the electrode 313 is grounded. Then, the application of the drive voltage to the electrodes 314b and 314c is stopped. As a result, ink droplets are ejected in the ink liquid chamber 312b and ink is supplied into the ink liquid chamber 312b.

[0030]

As is apparent from the above description, according to the present invention, the surface of the voltage portion on which the electrode is formed is different from the inner surface of the ink liquid chamber, and the electric field generated by the application to the electrode is different. The direction is substantially perpendicular to the polarization direction of the piezoelectric portion,
Moreover, since the deformation direction of the side wall is substantially parallel to the polarization direction of the piezoelectric portion, the electrode hardly contacts the ink in the ink liquid chamber. For this reason, the electrodes are less likely to be corroded by the water contained in the ink, and the ejection is prevented from becoming unstable. Therefore, it is possible to provide an ink ejecting apparatus having a long electrode life and high reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an ink ejecting apparatus in the process of being manufactured according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an ink ejecting apparatus of an embodiment of the invention.

FIG. 3 is an explanatory diagram showing an operation of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 4 is a sectional view showing an ink ejecting apparatus of a modified example of the invention.

FIG. 5 is a cross-sectional view showing an ink ejecting apparatus of a modified example of the invention.

FIG. 6 is a cross-sectional view showing a conventional ink ejecting apparatus.

FIG. 7 is an explanatory diagram showing an operation of a conventional ink ejecting apparatus.

FIG. 8 is a perspective view showing a conventional ink ejecting apparatus.

FIG. 9 is a block diagram showing a control unit of a conventional example.

FIG. 10 is a perspective view showing a conventional printer.

[Explanation of symbols]

 106 Polarization direction 111 Side wall 112 Ink liquid chamber 113 Electrode 114 Electrode

Claims (1)

[Claims] 1. An ink liquid chamber filled with ink, a side wall formed by a piezoelectric portion at least a part of which is separated from the ink liquid chamber, and an electrode formed in the piezoelectric portion. An ink ejecting apparatus that deforms the side wall by applying a voltage to the electrode to apply pressure to the ink in the ink liquid chamber to eject the ink, wherein a surface of the piezoelectric portion that forms the electrode is ink. Unlike the inner surface in the liquid chamber, the direction of the electric field generated by application to the electrode is substantially orthogonal to the polarization direction of the piezoelectric portion, and the deformation direction of the side wall is substantially parallel to the polarization direction of the piezoelectric portion. An ink jet device characterized by the above.