JPH07205422A - Ink jet device - Google Patents

Abstract

PURPOSE:To obtain an ink jet device eliminating a need for an insulating layer for insulating ink from an electrode and having a high yield and a superior high-volume production capability. CONSTITUTION:Grooves 103 are formed on a top surface 117 of a piezoelectric ceramics plate 102. A metallic electrode 108 is formed on the inner surfaces of the grooves 103 and the top surface 117. A cover plate 110 is bonded to the piezoelectric ceramics plate 102. Ink chambers 104 are formed correspondingly to the grooves 103. Deep grooves 111 are formed on a rear surface 118 of the piezoelectric ceramics plate 102. A metallic electrode 109 is formed on the side faces of the deep grooves 11 1 and the rear surface 118. Ink is jetted out of the ink chambers 104 by applying a voltage to the metallic electrode 109 and grounding the metallic electrode 108.

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 Among the non-impact type printers, which have been expanding the market to replace the impact type printers used up to now, the principle is the simplest, and multi-gradation and colorization are possible. Inkjet type printers are mentioned as being easy to use. Above all, a drop that ejects only the ink drops used for printing
The on-demand type is rapidly spreading due to its good injection efficiency and low running cost.

The Kaiser type disclosed in Japanese Patent Publication No. 53-12138 as a drop-on-demand type,
Alternatively, a thermal jet type disclosed in Japanese Patent Publication No. 61-59914 is a typical method.
Of these, the former is difficult to miniaturize, and the latter requires high heat resistance of the ink in order to apply high heat to the ink, and each has a very difficult problem.

A method proposed to solve the above defects at the same time is disclosed in Japanese Patent Laid-Open No. 63-247051.
It is the shear mode type disclosed in the publication.

As shown in FIG. 5, the shear mode type ink jet apparatus 600 comprises a bottom wall 601, a top wall 602 and a shear mode actuator wall 603 therebetween. The actuator wall 603 is bonded to the bottom wall 601 and is polarized in the direction of arrow 611.
And an upper wall 605 bonded to the ceiling wall 602 and polarized in the direction of arrow 609. The actuator walls 603 are paired to form an ink flow path 613 therebetween, and a space 615 narrower than the ink flow path 613 is formed between the next pair of actuator walls 603.

The nozzle 6 is provided at one end of each ink flow path 613.
A nozzle plate 617 having 18 is fixed, and electrodes 619 and 621 are provided as metal layers on both side surfaces of each actuator wall 603. The electrodes 619 and 621 are covered with an insulating layer (not shown) for insulating the ink. Then, the electrodes 619, 6 facing the space 615
Reference numeral 21 is connected to a ground 623, and electrodes 619 and 621 provided in the ink flow path 613 are connected to a silicon chip 625 which provides an actuator drive circuit.

Next, a method for manufacturing the ink jet device 600 will be described. First, the piezoelectric ceramic layer polarized in the arrow 611 is bonded to the bottom wall 601, and the piezoelectric ceramic layer polarized in the arrow 609 is bonded to the ceiling wall 602. The thickness of each piezoelectric ceramic layer is as follows.
Equal to 5 height. Next, parallel grooves are formed in the piezoelectric ceramics layer by rotating a diamond cutting disk or the like to form a lower wall 607 and an upper wall 605. Then, the electrode 61 is formed on the side surface of the lower wall 607 by vacuum deposition.
9 is formed, and the insulating layer is provided on the electrode 619.
Similarly, the electrode 621 and the insulating layer are provided on the side surface of the upper wall 605.

The zenith of the upper wall 605 and the zenith of the lower wall 607 are adhered to each other to form an ink flow path 613 and a space 615. Next, a nozzle plate 617 in which the nozzles 618 are perforated is bonded to one ends of the bottom wall 601, the top wall 602, and the actuator wall 603 so that the nozzles 618 correspond to the ink flow paths 613, and the ink flow paths 613 The other end of the space 615 is the silicon chip 625 and the ground 62.
Connect to 3.

Then, the electrode 61 of each ink flow path 613
When the silicon chip 625 applies a voltage to 9, 621, each actuator wall 603 undergoes piezoelectric thickness slip deformation in a direction of increasing the volume of the ink flow path 613, and after a predetermined time, the voltage application is stopped and the ink flow is stopped. Road 613
Of the ink flow path 61 from the increased state to the natural state.
Pressure is applied to the ink in the nozzle 3, and ink drops are generated in the nozzle 61.
It is injected from 8.

[0010]

However, in the ink ejecting apparatus 600 having the above-described structure, the electrodes 619 and 621 facing the space 615 are connected to the ground 623,
Electrodes 619 and 62 provided in the ink flow path 613
Since No. 1 is connected to the silicon chip 625 which provides an actuator drive circuit, a voltage is applied to the electrodes 619 and 621 in each ink flow path 613 to eject ink. Therefore, the electrode 619 in the ink flow path 613,
The 621 must be covered with the insulating layer to insulate it from the ink. This is because if the ink has high conductivity without the insulating layer, it may cause a short circuit, and even if the ink is not so high in conductivity, the electrode 619, 621 is deteriorated, the actuator wall 603 is not sufficiently deformed, and the printing quality is deteriorated. Therefore, an insulating layer is required to insulate the ink from the electrodes 619 and 621, which requires facilities and processes, which lowers productivity and raises costs.

Further, in Japanese Patent Laid-Open No. 63-247051, which shows the ink ejecting apparatus 600, only the ink flow path 613 is filled with ink and the space 615 is not filled with ink. Not disclosed. Therefore, for example, through holes communicating with the ink flow passages 613 are provided in the bottom wall 601 or the top wall 602 corresponding to the respective ink flow passages 613, and ink is supplied only to the ink flow passages 613, and ink is supplied to the space 615. However, it is difficult to form these through holes because of their small size, the yield is poor, and it takes time to process, resulting in poor mass productivity. .

The present invention has been made in order to solve the above-mentioned problems, and provides an ink ejecting apparatus which does not require an insulating layer for insulating ink from an electrode, has a high yield, and is excellent in mass productivity. The purpose is to

[0013]

In order to achieve this object, according to claim 1 of the present invention, a plate at least a part of which is made of piezoelectric ceramic, and a plurality of first grooves formed on one surface of the plate are provided. And a cover member for closing the opening of the first groove on one surface of the plate, a first electrode formed on the side surface of the inner surface of the first groove, and A second electrode electrically connecting the first electrode, and a second groove formed between the first grooves on the other surface of the plate opposite to the one surface, and a bottom surface of the second groove. A third electrode that is not formed and is formed on the side surface of the second groove, a connecting means that electrically connects the third electrodes located on both outer sides of each first groove, and the third electrode on the plate. One groove is opened and the second groove is opened. A manifold for supplying ink to the first groove from the other side, a voltage is applied to the third electrode via the connecting means, and the first electrode is grounded via the second electrode, The piezoelectric ceramic on the side surface of the first groove is deformed, and the ink supplied from the manifold is ejected from the first groove.

According to a second aspect of the present invention, the second electrode is formed on the one surface of the plate, and the connecting means is an electrode formed on the other surface of the plate.

According to a third aspect of the present invention, the plate is formed of piezoelectric ceramics, the first electrode is formed in the entire area of the inner surface of the first groove, and the second groove is formed in a depth of the plate up to the vicinity of the one surface. That is, the third electrode is formed in a region from the other surface of the plate to substantially the center of the depth of the first groove.

According to a fourth aspect of the present invention, the plate is formed by laminating two piezoelectric ceramics having different polarization directions, the first electrode is formed on the entire inner surface of the first groove, and the second groove is formed. Is the depth to the vicinity of the one surface of the plate, and the third electrode is formed in the entire region of the side surface of the second groove.

According to a fifth aspect of the present invention, a conductive film is formed on the surface of the cover member on the side that closes the first groove.

According to a sixth aspect of the present invention, the cover member is formed with a manifold for supplying ink to the first groove.

[0019]

In the ink jet apparatus of the present invention having the above structure, the second electrode electrically connects the first electrodes in all the first grooves, and the second groove is the one surface of the plate. On the other surface opposite to the above, the connecting means are formed between the first grooves and individually electrically connect the third electrodes located on both outer sides of the respective first grooves. Then, a voltage is applied to the third electrode through the connecting means, the first electrode is grounded through the second electrode, the piezoelectric ceramics on the side surface of the first groove is deformed, and The supplied ink is ejected from the first groove.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The structure and manufacturing method of the ink ejecting apparatus will be described. As shown in FIG. 1, the ink ejecting apparatus 100 includes a piezoelectric ceramic plate 102 and a cover plate 110.
And the nozzle plate 14.

The piezoelectric ceramic plate 102 is
It is made of a ceramic material such as lead zirconate titanate (PZT) and is polarized in the direction of arrow 105. A plurality of grooves 103 as first grooves are formed on the piezoelectric ceramic plate 102 by cutting from the surface 117 side with a diamond blade or the like. Those grooves 10
3 has the same depth and is parallel. Those grooves 10
3 is one end surface 116 of the piezoelectric ceramic plate 102.
Is processed so that the other end surface 115 on the opposite side does not open.

The entire inner surface of the groove 103 and the surface 11
A metal electrode 108 is formed on 7 by plating or the like.
Here, the metal electrode 108 formed on the inner surface of the groove 103 corresponds to the first electrode, and the metal electrode 1 formed on the surface 117.
08 corresponds to the second electrode.

Cover plate 11 made of alumina
At 0, an ink introduction port 114 and a manifold 101 are formed. A metal electrode 119 is formed on the surface of the cover plate 110 on which the manifold 101 is formed. Then, the piezoelectric ceramic plate 102
Of the epoxy-based adhesive 121
(FIG. 4) to adhere. As a result, the opening of the groove 103 on the surface 117 side is covered, and the ink chamber 104
Is formed. The ink chamber 104 formed in this way
Is almost covered with the metal electrodes 108 and 119 except the portion facing the nozzle plate 14 described later.
A first flexible substrate (not shown), which will be described later, is disposed between the piezoelectric ceramic plate 102 and the cover plate 110 on the end portion 115 side of the piezoelectric ceramic plate 102, and the piezoelectric ceramic plate 102 and the cover plate 110. And are glued together.

After the cover plate 110 is adhered,
As shown in FIG. 2, the ink ejecting apparatus 100 is turned upside down, and on the back surface 118 of the piezoelectric ceramic plate 102, a deep groove 111 as a second groove is cut between the ink chambers 104 by a diamond blade or the like. here,
The diamond blade for processing the deep groove 111 has a tapered shape so as not to be damaged during processing of a fine and considerable depth. Then, the deep groove 111 has a back surface 118.
To the vicinity of the surface 117 (FIG. 1) and is processed to open at both ends 115 and 116 of the piezoelectric ceramic plate 102. By processing the deep groove 111, the partition wall 106 separating the deep groove 111 and the ink chamber 104 is formed.
Is formed. The partition 106 is polarized in the direction of arrow 105.

The metal electrodes 109 are formed on both side surfaces of the deep groove 111 by sputtering or the like, and the back surface 118 is formed.
To about half the height of the ink chamber 104. In addition, this sputtering is arrow 11
The deep groove 111
The metal electrodes 109 are formed on both side surfaces and the back surface 118 of the.
Here, the metal electrode 109 formed on the side surface of the deep groove 111
Corresponds to the third electrode, and the piezoelectric ceramic plate 102
The metal electrode 109 formed on the back surface 118 of the above corresponds to the connecting means. The metal electrode 109 thus formed
Surrounds the outer half area of each ink chamber 104, and the metal electrode 109 is electrically independent for each ink chamber 104.

Next, as shown in FIG. 1, one of the piezoelectric ceramic plate 102 and the cover plate 110 is attached to the nozzle plate 14 so that each nozzle 12 communicates with each ink chamber 104 using an epoxy adhesive or the like. End face 116
Glue to.

The pattern (not shown) of the first flexible substrate arranged as described above is formed on the surface 117 of the piezoelectric ceramic plate 102.
08 and the metal electrode 119 of the cover plate 110, and the metal electrode 1 formed on the back surface 118.
09 are individually electrically connected to respective patterns (not shown) of the second flexible substrate (not shown). The patterns of the first and second flexible boards are connected to a control unit described later.

Next, the configuration of the control unit will be described with reference to FIG. 3 showing a block diagram of the control unit. The metal electrode 109
(FIG. 1) is electrically connected individually to the LSI chip 151 through the second pattern of the flexible substrate, and the metal electrode 108 (FIG. 1) is electrically connected through the first pattern of the flexible substrate. LSI chip 15
1 is connected to the clock line 152 and the data line 1
53, the voltage line 154 and the earth line 155 are also LS
It is connected to the I-chip 151. LSI chip 151
Determines which nozzle 12 should eject an ink drop from the data appearing on the data line 153, based on the continuous clock pulse supplied from the clock line 152, and ejects the ink chamber 104 (FIG. 1). The voltage V of the voltage line 154 is applied to the metal electrode 109 corresponding to (4). Further, the earth line 155 is connected to the metal electrode 109 corresponding to the ink chamber 104 not ejected and the metal electrode 108 in the ink chamber 4.

Next, the operation of the ink ejecting apparatus 100 of this embodiment will be described. In order to eject ink droplets from the ink chamber 104b of FIG. 4B, the LSI chip 151 (FIG. 3)
Applies a voltage pulse to the metal electrode 109b corresponding to the ink chamber 104b, and grounds the metal electrode 109 corresponding to another ink chamber 104 and the metal electrode 108 in the ink chamber 104. Then, electric fields in the directions of the arrows 113b and 113c are applied to the partition walls 106b and 106c.
8 and the electrode 109b face each other, and the partitions 106b and 106c move away from each other. At this time, an electric field is also generated in a portion below the bottom surface of the groove 103 (FIG. 1) of the piezoelectric ceramic plate 102, and the piezoelectric ceramic in the electric field generating portion is deformed, but this affects the volume of the ink chamber 104b. Absent.

Due to the deformation of the partition walls 106b and 106c, the volume of the ink chamber 104b increases and the pressure in the ink chamber 104b decreases. This state is maintained for the time indicated by L / a. In the meantime, ink is supplied to the ink chamber 104b from an ink supply source (not shown) through the ink introduction port 114 and the manifold 101. The above L / a is the time required for the pressure wave in the ink chamber 104 to propagate one way in the longitudinal direction of the ink chamber 104 (from the manifold 101 to the nozzle plate 14 or vice versa). It is determined by the length L of the ink chamber 104 and the speed of sound a in the ink.

According to the propagation theory of the pressure wave, the pressure in the ink chamber 104b reverses and changes to a positive pressure just after a time of L / a from the start-up, but it is applied to the electrode 109b at this timing. The voltage being set is returned to 0V. Then, the partition walls 106b and 106c return to the state before deformation (FIG. 4A), and pressure is applied to the ink. At that time, the positive pressure and the partition walls 106b and 106c return to the state before the deformation, and the generated pressure is added to each other, and a relatively high pressure is applied to the ink in the ink chamber 104b, and the ink droplets are generated. It is ejected from the nozzle 12 (FIG. 1) corresponding to the ink chamber 104b.

In the above embodiment, first, the driving voltage is applied in the direction in which the volume of the ink chamber 104b increases,
Next, the application of the drive voltage was stopped, the volume of the ink chamber 104b was reduced to a natural state, and ink droplets were ejected from the ink chamber 104b. First, the drive voltage was changed so that the volume of the ink chamber 104b was reduced by a metal electrode. A voltage is applied to 109 to eject ink droplets from the ink chamber 104b, and then the application of the drive voltage is stopped to increase the volume of the ink chamber 104b from the reduced state to the natural state, thereby ejecting ink into the ink chamber 104b. May be supplied.

As described above, in the ink ejecting apparatus 100 of this embodiment, a voltage pulse is applied to the metal electrode 109b corresponding to the ink chamber 104b that ejects ink, and the metal electrode 108 in the ink chamber 104 is grounded. Nozzle 12
Since the ink droplets are ejected from, the voltage is not applied to the metal electrode 108 on the inner surface of the ink chamber 104 filled with the ink. Therefore, unlike the conventional case, the insulating layer for insulating the ink from the electrode in the ink chamber is not required, and there is no need for equipment and process for that, so that the productivity can be improved and the cost can be reduced. You can Further, since no voltage is applied to the metal electrode 108 in the ink chamber 104 filled with ink, the metal electrode 108 has good corrosion resistance. Therefore, the durability of the metal electrode 108 is long and the life of the ink ejecting apparatus 100 is long.

Further, since air is present in the deep groove 111, the partition wall 106 is easily deformed and the driving voltage may be low. In addition, a partition 106c of an ink chamber 104b,
Since the deformation of 106d does not affect the other ink chambers 104, ink droplets are satisfactorily ejected from each ink chamber 104 and the print quality is good.

Further, since only the groove 103 is opened on the surface 117 of the piezoelectric ceramic plate 102 to which the manifold 101 forming surface of the cover plate 110 is adhered, the manifold for supplying ink to the ink chamber 104 corresponding to the groove 103. The shape of 101 may be simple, processing for it can be easily performed, yield is high, and mass productivity is excellent.

Further, since each metal electrode 109 is exposed to the outside over the entire length in the longitudinal direction of the ink ejecting apparatus 100, electrical connection with the pattern of the flexible board is easy and reliable.

The inner surface of the ink chamber 104 is the metal electrode 1
Since it is almost covered with 08 and 119, the electric field does not enter the ink chamber 104, and the electric field is not applied to the ink. Therefore, the electrochemical change of the ink due to the electric field does not occur, and the deterioration of the ink is prevented.

A reinforcing plate may be provided on the back surface 118 of the piezoelectric ceramic plate 102 so that dust or dirt does not enter the deep groove 111 and the partition wall 106 is not destroyed by an external force. Good. In addition, a pattern electrically connected to the metal electrode 109 is formed on the reinforcing plate so that the metal electrode 1 can be formed without using the flexible substrate.
09 may be connected to the control unit. Further, on the back surface 118 of the piezoelectric ceramic plate 102, a connector as a connecting means is provided on the reinforcing plate without forming the metal electrode 109 to electrically connect the metal electrodes 109 outside the respective grooves 103. Good.

Further, in this embodiment, the cover plate 110 is adhered to the surface 117 of the piezoelectric ceramic plate 102, but two piezoelectric ceramic plates provided with a groove corresponding to the groove 103 and the deep groove 111 and a deep groove are provided. The surfaces of the piezoelectric ceramic plates on the groove forming side may be bonded to each other so that the grooves face each other.

Further, in this embodiment, the groove 103 and the deep groove 111 were formed in one piezoelectric ceramic plate 102, but ceramics such as alumina which are not piezoelectrically deformable are laminated on the piezoelectric ceramics to prevent piezoelectric deformation. The groove 103 may be processed from the ceramic side and the deep groove 111 may be processed from the piezoelectric ceramic side.

Further, in this embodiment, the groove 103 and the deep groove 111 are formed on one piezoelectric ceramic plate 102, the metal electrode 108 is formed on the entire inner surface of the groove 103, and the back surface 118 on the side surface of the deep groove 111 is formed. Although the metal electrode 109 is formed in a region up to about half the height of the ink chamber 104 and the piezoelectric thickness is slip-deformed on the partition wall 106, two piezoelectric ceramic plates are laminated so that the polarization directions are opposite to each other. Then, the groove 103 and the deep groove 111
A metal electrode is formed on the entire inner surface of the groove 103, and a metal electrode is formed on the entire side surface of the deep groove 111.
An electric field may be generated in the entire region of the partition wall, and the piezoelectric ceramics in the upper half and the region piezoelectric ceramics in the lower half of the partition wall may be subjected to piezoelectric thickness sliding deformation to be deformed in the same direction.

[0043]

As is apparent from the above description, according to the ink ejecting apparatus of the present invention, a voltage is applied to the third electrode via the connecting means and the second electrode is applied via the second electrode. One electrode is grounded, the piezoelectric ceramics on the side surface of the first groove is deformed, and the ink supplied from the manifold is ejected from the first groove. Therefore, the first electrode in the first groove that is in contact with the ink is always grounded, and no current flows in the ink. Therefore, an insulating layer for insulating the ink from the first electrode is not required, the equipment and process therefor can be omitted, and the productivity can be increased and the cost can be reduced. Also, since the first groove is processed from one surface of the plate and the second groove is processed from the other surface of the plate, the shape of the manifold for supplying the ink to the first groove is simple and the processing is easy. And has excellent mass productivity.

[Brief description of drawings]

FIG. 1 is a perspective view showing an ink ejecting apparatus according to an embodiment of the invention.

FIG. 2 is an explanatory diagram showing a manufacturing process of the ink ejecting apparatus of the embodiment.

FIG. 3 is a block diagram showing a control unit of the ink ejecting apparatus of the embodiment.

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

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

[Explanation of symbols]

 100 Ink Ejection Device 102 Piezoelectric Ceramic Plate 103 Groove 104 Ink Chamber 105 Polarization Direction 106 Partition 108 Metal Electrode 109 Metal Electrode 110 Cover Plate 111 Deep Groove 119 Metal Electrode

Claims (6)

[Claims] 1. A plate at least a part of which is formed of piezoelectric ceramics, a plurality of first grooves formed on one surface of the plate, and a cover member which closes an opening of the first groove on one surface of the plate. In an ink ejecting apparatus having, a first electrode formed on a side surface of an inner surface of the first groove, a second electrode electrically connecting the first electrodes in all the first grooves, and the plate of the plate. On the other surface opposite to the one surface, a second groove formed between each first groove, and a third electrode not formed on the bottom surface of the second groove and formed on the side surface of the second groove, Connecting means for individually electrically connecting the third electrodes located on both outer sides of each first groove, the first groove in the plate is opened, from the surface of the second groove is not opened, the A manifold for supplying ink to the first groove, A voltage is applied to the third electrode via the connecting means, the first electrode is grounded via the second electrode, the piezoelectric ceramics on the side surface of the first groove is deformed, and the voltage is supplied from the manifold. An ink ejecting apparatus, characterized in that the ejected ink is ejected from the first groove. 2. The ink jetting device according to claim 1, wherein the second electrode is formed on the one surface of the plate, and the connecting means is an electrode formed on the other surface of the plate. apparatus. 3. The plate is formed of piezoelectric ceramics, the first electrode is formed in the entire area of the inner surface of the first groove, and the second groove has a depth up to the vicinity of the one surface of the plate. The ink ejecting apparatus according to claim 1, wherein the third electrode is formed in a region from the other surface of the plate to substantially the center of the depth of the first groove. 4. The plate is formed by stacking two piezoelectric ceramics having different polarization directions, the first electrode is formed on the entire inner surface of the first groove, and the second groove is The ink ejecting apparatus according to claim 1, wherein the depth is up to the vicinity of the one surface of the plate, and the third electrode is formed in the entire area of the side surface of the second groove. 5. The ink ejecting apparatus according to claim 3, wherein a conductive film is formed on a surface of the cover member that closes the first groove. 6. The ink ejecting apparatus according to claim 1, wherein the cover member is formed with a manifold for supplying ink to the first groove.