JP3206235B2 - 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. 4, 5, 6, 7, and 8 are schematic diagrams of the conventional examples. Hereinafter, the configuration of the conventional example will be specifically described with reference to FIG. A piezoelectric ceramic plate 1 having a plurality of grooves 15 and a partition wall or side wall 11 separating the grooves 15 and having been subjected to a polarization treatment in the direction of arrow 4 and a cover plate 2 made of a ceramic material or a resin material are bonded by epoxy. By bonding via the bonding layer 3 made of a system adhesive or the like, the groove 15 becomes a plurality of ink liquid chambers 12 spaced from each other in the lateral 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 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 ink chambers 12
The inside is filled with ink.

Next, FIG. 5 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.
The ink droplets are ejected from the nozzles 32 (FIG. 6) communicating with the nozzles. When the application of the driving voltage is stopped, the side walls 11b
11c return to the position before deformation (see FIG. 4), the ink pressure in the ink liquid chamber 12b decreases, and the ink supply port 2
1 (FIG. 6), ink is supplied into the ink liquid chamber 12b through the manifold 22 (FIG. 6).

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 positions before deformation (see FIG. 4).

Next, FIG. 6 is a perspective view of an 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.
Create 5. The groove 15 is a parallel groove having the same depth over almost the entire area of the piezoelectric ceramic plate 1, but is formed so as to gradually become shallower as it approaches the end face 17, and becomes 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 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 groove 18, the electrode 13 is formed on the entire side surface and bottom surface. Also,
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 the epoxy adhesive 3 (FIG. 4) so that each groove 15 forms the ink liquid chamber 12 having the above-described 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 13 on the bottom surface of the shallow groove 18 and the pattern 42 of the conductive layer 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. 7 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. 8 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. 5, 6, and 7. The ink ejection device 61 is fixed on a carriage 62, the ink supply tube 63 communicates with the ink supply port 21 (FIG. 6), the LSI chip 51 (FIG. 7) 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. 6), 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 problems, and provides an ink ejecting apparatus which can eject ink effectively, has a long electrode life, and has high reliability. The purpose is to:

[0014]

According to claim 1 of the Means for Solving the Problems The present invention to achieve this purpose, a plurality of partition walls made of piezoelectric material separating the plurality of ink chambers b ink is filled, its
Polarized in a direction parallel to the side of the partition wall facing the ink chamber
A partition, electrodes formed at both ends in the polarization direction of the partition and biased to one side in the width direction of the partition to generate an electric field substantially parallel to the polarization direction, and control means for applying a voltage to the electrode. And a deformation of the one side portion of the partition wall caused by the electric field in a direction in which the one side portion extends or contracts, thereby deforming the entire partition wall in a direction to increase or decrease the volume of the ink liquid chamber.

According to a second aspect of the present invention, in the configuration of the first aspect, a partition is provided on both sides of the ink liquid chamber, and a voltage is applied to the electrodes of the two partitions so as to deform the two partitions in opposite directions. the shall be the feature.

According to a third aspect of the present invention, in the configuration according to the second aspect, a partition shared by an adjacent ink chamber among the plurality of ink chambers is used when ink is ejected from one ink chamber and when the other ink chamber is used. The voltage applied to the electrode is controlled so that the ink is deformed in the opposite directions when ink is ejected from the liquid chamber.

[0017] According to claim 4, a plurality of partition walls made of piezoelectric material separating the plurality of ink chambers b ink is filled,
Polarized in a direction parallel to the side of the partition facing the ink chamber
Is, a plurality of partition walls that have a two areas in the width direction are bisected by a plane substantially parallel to the polarization direction, of the two regions of the partition wall, and substantially parallel polarization directions with respect to one side of the region An electrode for generating an electric field, wherein the one side region is deformed in a direction of extension or contraction by a piezoelectric effect, and the partition is deformed in a direction substantially orthogonal to the polarization direction.

According to a fifth aspect of the present invention, when the ink is ejected from the first ink liquid chamber of the adjacent ink liquid chambers, the two partition walls of the first ink liquid chamber are moved in opposite directions. The first ink chamber and the second ink chamber are shared when the voltage applied to the electrodes of both partition walls is controlled so that the ink is ejected from the second ink chamber adjacent to the first ink chamber. And the other partition of the second ink liquid chamber is deformed in the direction opposite to the direction of deformation of the common partition. And control means for controlling the voltage applied to the electrodes.

According to a sixth aspect of the present invention, in the configuration according to the first or fourth aspect, the ink liquid chamber includes the partition and a cover plate to which one end of the partition is connected. Are connected via an elastic body.

[0020]

According to the present invention having the above-described structure, an electric field substantially parallel to the polarization direction is generated in a portion of the partition wall deviated to one side in the width direction, and the one side portion of the partition wall is deformed in the extension or contraction direction. The entire partition is deformed in the direction of the ink liquid chamber, and ink is ejected from the ink liquid chamber.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first 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, on the lower surface of the piezoelectric ceramic plate 101 that has been subjected to the polarization process in the direction of the arrow 141,
Electrodes 131 made of a metal such as aluminum, nickel, or gold, or a conductive resin, and arranged at regular intervals are formed by vacuum deposition, sputtering, chemical plating, screen printing, or the like. On the upper surface of the piezoelectric ceramic plate 101, a metal such as aluminum, nickel, or gold, a conductive resin, or the like, and an electrode 132 is similarly formed.
The electrodes 132 are arranged at regular intervals at positions corresponding to the electrodes 131. Then, the surface of the piezoelectric ceramic plate 101 on which the electrodes 131 are formed and the base plate 102 made of ceramics, resin, metal material, or the like.
Are bonded via a bonding layer 111 made of an epoxy adhesive or the like.

Next, the piezoelectric ceramic plate 101
Then, a plurality of grooves 123 are formed by grinding using a thin disk-shaped diamond blade or the like. At this time, the electrode 132 is arranged on the partition wall separating the groove 123, that is, on the upper surface of the side wall 121. The electrode 132 is
It is arranged on the left side of the upper surface of the side wall 121 corresponding to the position where the width direction of the side wall 121 is bisected from the center. The electrode 131 formed on the bottom surface of the piezoelectric ceramic plate 101 is arranged at a position corresponding to the left side of the side wall 121.

Next, the surface of the piezoelectric ceramic plate 101, on which the electrodes 132 are formed, and the cover plate 103 made of ceramics, resin, metal material, etc. are interposed via a bonding layer 112 made of an epoxy adhesive having elasticity. Joined. Thus, the plurality of grooves 123 are
Accordingly, a plurality of ink liquid chambers 122 having a space in the horizontal direction are formed. 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. In all the ink liquid chambers 122,
The ink is filled.

It should be noted that the electrodes 131 and 132 only need to be between 1/5 and 4/5 of the width of the side wall 121 according to the experimental results. One end of each of the electrodes 131 and 132 is located on the side wall 1.
21 substantially coincides with the position of the surface in contact with the ink liquid chamber 122.

The electrodes 131 and 132 are L
It is connected to the SI chip 155 (FIG. 3). As shown in FIG. 3, the LSI chip 155 also includes a clock line 52, a data line 53, a positive voltage line 154, a negative voltage line 156, and a ground line 55.
55. The LSI chip 155 outputs the continuous clock pulse 5 supplied from the clock line 52.
2, it is determined from the data appearing on the data line 53 from which nozzle 32 (FIG. 6) the ink droplet should be ejected, and the electrode 132 on both side walls 121 in the ink liquid chamber 122 to be driven is determined. , The voltage V of the positive voltage line or the voltage −V of the negative voltage line is applied, and the voltage 0 of the ground line 55 is applied to the electrodes 132 and all the electrodes 131 other than the side walls 121.

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, LS is set according to desired print data.
When the I chip 155 determines that ink is to be ejected from the ink liquid chamber 122b, for example, the LSI chip 155 rapidly applies a positive drive voltage to the electrode 132b and a negative drive voltage to the electrode 132c, and the electrodes 131b and 131c. To ground. As a result, a driving electric field in the direction of arrow 151b acts on the portion of side wall 121b sandwiched between electrode 131b and electrode 132b, and the direction of arrow 151c acts on the portion of sidewall 121c sandwiched between electrode 131c and electrode 132c. Drive electric field acts.

At this time, since the driving electric field direction 151b and the polarization direction 141 are parallel and opposite to each other, the side wall 121b
The portion sandwiched between the electrode 131b and the electrode 132b tends to contract and deform due to the piezoelectric longitudinal effect. However, the portion of the side wall 121b other than the portion sandwiched between the electrode 131b and the electrode 132b does not shrink and deform because no driving electric field acts thereon. For this reason, the electrode 131 of the side wall 121b
compressive strain, that is, negative strain acts on the portion sandwiched between the electrode b and the electrode 132b, and the compressive strain acts on the portion of the side wall 121b other than the portion sandwiched between the electrode 131b and the electrode 132b. , Tensile strain in the opposite direction, that is, positive strain acts. Therefore, the side wall 121b rapidly deforms into a bimorph-like shape toward the inside of the ink liquid chamber 122b.

The driving electric field direction 151c and the polarization direction 1
Since 41 is parallel and in the same direction, the portion of the side wall 121c sandwiched between the electrode 131c and the electrode 132c tends to rapidly expand and deform in the polarization direction 141 due to the piezoelectric longitudinal effect. However, the electrode 1 on the side wall 121c
The portion other than the portion sandwiched between 31c and the electrode 132c is
No elongation deformation occurs because no driving electric field acts. Therefore,
The side wall 121c deforms in a bimorph-like manner like the side wall 121b, and rapidly deforms toward the inside of the ink liquid chamber 122b.

Due to this deformation, the volume of the ink liquid chamber 122b is reduced, the ink pressure in the ink liquid chamber 122b is rapidly increased, a pressure wave is generated, and the nozzle 32 (FIG. 6) communicates with the ink liquid chamber 122b. Ink droplets are ejected.
When the LSI chip 155 stops applying the drive voltage, the side walls 121b and 121c return to the positions before deformation (see FIG. 1), so that the ink pressure in the ink liquid chamber 122b decreases and the ink supply port 21 (FIG. ) To manifold 22
Ink is supplied into the ink liquid chamber 122b through (FIG. 6).

Next, the LSI chip 155 is connected to the ink liquid chamber 1.
If it is determined that ink is to be ejected from the ink liquid chamber 122c adjacent to the electrode 132b, the LSI chip 155
c, rapidly apply a positive drive voltage to the electrode 132d, ground the electrodes 131c and 131d, and deform the side walls 121c and 122d toward the inside of the ink liquid chamber 122c to discharge the ink. Inject.

As described above, in the ink ejecting apparatus of this embodiment, the entire electrode 131 and most of the electrode 132 do not come into contact with the ink inside the ink liquid chamber 122. Therefore, the electrodes 131 and 132 are less likely to be corroded by moisture or the like contained in the ink, and the ejection is less likely to be unstable. Therefore, it is possible to provide an ink ejecting apparatus in which the life of the electrodes 131 and 132 is long and the reliability is high.

In the above embodiment, first, the volume of the ink liquid chamber 122 is reduced by applying a driving voltage to eject ink droplets, and then the application of the driving voltage is stopped to thereby stop the ink liquid chamber 122. Increase the volume of the ink chamber 1
Although the ink was supplied into the ink chamber 22, the volume of the ink liquid chamber 122 was increased by applying a driving voltage to supply the ink into the ink liquid chamber 122, and then the application of the driving voltage was stopped. The ink droplets may be ejected by reducing the volume of the liquid chamber 122.

In the above embodiment, the electrode 131
Although the electrodes 131 and 132 are formed only on the left part of all the side walls 121, the electrodes 131 and 132 may be formed only on the right part of some or all of the side walls.

Further, in the above embodiment, the electrode 131
Is a lower side wall 121 of the piezoelectric ceramic plate 101
However, the electrode 131 may be formed continuously below the piezoelectric ceramics 101 in common to all the side walls 121.

Further, the base plate 102 may be omitted.

Further, in the above embodiment, the electrode 132
Is formed on the upper surface of the side wall 121, but may be formed on the cover plate 103.

In the above embodiment, the grooves 123 were formed after the electrodes 131 and 132 were formed on the piezoelectric ceramic plate 101. However, after the grooves 123 were formed, the electrodes 13 were formed.
1, 132 may be formed.

In the above-described embodiment, the side wall 121 is formed of one piezoelectric plate. However, a plurality of piezoelectric plates may be stacked. Further, electrodes may be provided between the layers.

[0040]

As is apparent from the above description, in the ink jetting apparatus of the present invention, an electric field substantially parallel to the polarization direction is generated in a portion of the partition wall deviated to one side in the width direction, and the partition wall has one side. The deformation of the side portion in the direction of extension or contraction causes the entire partition to be rapidly deformed in the direction of the ink liquid chamber, so that ink can be ejected effectively and most of the electrodes are in contact with the ink inside the ink liquid chamber. The electrodes can be arranged at both ends of the partition wall so as not to be corroded, the electrodes are less likely to be corroded by moisture or the like contained in the ink, and the ejection is less likely to be unstable. Therefore, the life of the electrode is long, and the reliability of the ink ejecting apparatus is high.

[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 block diagram of a control unit of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional ink ejecting apparatus.

FIG. 5 is an explanatory diagram showing an operation of a conventional ink ejecting apparatus.

FIG. 6 is a perspective view of a conventional ink ejecting apparatus.

FIG. 7 is a block diagram of a control unit of a conventional example.

FIG. 8 is a perspective view of a conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Piezoelectric ceramic plate 121 Side wall 122 Ink liquid chamber 131 Electrode 132 Electrode 141 Polarization direction 155 LSI chip

Claims (6)

(57) [Claims] The method according to claim 1 a plurality of ink chambers b ink is filled
A plurality of partition walls made of a piezoelectric material which are separated from each other;
A partition wall polarized in a direction parallel to the side surface facing the link chamber ; and electrodes formed at both ends of the partition wall in the polarization direction and biased to one side in the width direction of the partition wall to generate an electric field substantially parallel to the polarization direction. And control means for applying a voltage to the electrode, and the partition is entirely deformed in the direction of extension or contraction of the one side of the partition caused by the electric field, so that the entire partition is in the ink liquid chamber.
An ink ejecting apparatus characterized by deforming in a direction to increase or decrease the volume of the ink. 2. The ink jet according to claim 1, wherein partitions are provided on both sides of the ink liquid chamber, and a voltage is applied to the electrodes of both partitions so that the partitions are deformed in directions opposite to each other. apparatus. 3. A partition shared by adjacent ink chambers among the plurality of ink liquid chambers, the partition wall being used when ink is ejected from one ink liquid chamber and when ink is ejected from the other ink liquid chamber. The voltage applied to the electrode is controlled so that the electrode is deformed in the opposite direction.
The ink ejecting apparatus according to claim 1. The method according to claim 4 a plurality of ink chambers b ink is filled
A plurality of partition walls made of a piezoelectric material which are separated from each other;
Two regions that are polarized in a direction parallel to the side surface facing the ink chamber and whose width direction is bisected by a plane that is approximately parallel to the polarization direction.
A plurality of partition walls that Yusuke, wherein among the two regions of the partition wall, and an electrode for generating a polarization direction substantially parallel electric field to one side of the region, the side region extending or contraction by the piezoelectric effect direction Wherein the partition wall is deformed in a direction substantially perpendicular to the polarization direction. 5. When the ink is ejected from the first ink liquid chamber among the adjacent ink liquid chambers, the electrodes of the two ink walls are deformed in opposite directions to each other. When controlling the voltage to be applied and ejecting ink from the second ink liquid chamber adjacent to the first ink liquid chamber,
The partition commonly used by the first ink chamber and the second ink chamber is deformed in a direction opposite to the direction in which the ink is ejected from the first ink chamber, and the other partition of the second ink chamber is also used by the common use. 5. The ink ejecting apparatus according to claim 4, further comprising control means for controlling a voltage applied to the electrode so as to deform the partition wall in a direction opposite to the deformation direction. 6. The ink liquid chamber includes the partition and a cover plate to which one end of the partition is connected, and the partition is connected to the cover plate via an elastic body. The ink ejecting apparatus according to claim 1, wherein