JPH08192515A - Ink jet device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an ink ejecting apparatus which is excellent in mass productivity and reliability and which can be easily electrically connected. [Structure] The actuator plate 101 has, for example, a depth of 4
A plurality of grooves 117 having a width of 00 μm and a width of 240 μm are formed. In addition, the partition wall 111 that becomes the side surface of the groove 117 is
For example, the width is 80 μm. The electrode 124 is formed on the inner surface of the groove 117 only on the upper half of the side surface. Height 40
A resin cavity plate 102 having a side wall 112 of 0 μm, a width of 80 μm, and a length of 9 mm and a cavity 119 sandwiched by the side wall 112 is manufactured by an injection molding method. The actuator plate 101 and the cavity plate 102 are bonded so that the side wall 112 corresponds to the center of the groove 117 and the partition wall 111 corresponds to the center of the cavity 119. Then, the groove 117 becomes a plurality of ink liquid chambers 121 that are laterally spaced from each other.

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, a printer head using a piezoelectric ink jet has been proposed. This is called a drop-on-demand method, and by changing the volume of the ink flow path by the shape change due to the piezoelectric effect of the piezoelectric transducer, the ink in the ink flow path is discharged from the orifice when the volume is reduced. The ink is ejected and the ink is introduced into the ink flow path from the other valve when the volume is increased. Then, a plurality of such ejecting devices are arranged close to each other, and ink is ejected from the ejecting device at a predetermined position to form a desired character or image.

Examples of this type of liquid droplet ejecting apparatus include, for example, JP-A-63-247051 and JP-A-63-25.
Some are disclosed in Japanese Patent No. 2750. 12 and 13 show schematic views of these conventional examples. Hereinafter, a conventional example will be described in detail with reference to FIG. 12 showing a partial cross-sectional view of the array. The plurality of sidewalls 2a, 2b, 2c, 2d, 2
The piezoelectric ceramics plate 1 having e and polarized in the direction of the arrow 51 and the cover plate 21 made of a metal material, a glass material, a ceramics material, or the like
A plurality of ink flow paths 31a, 31b, 31c, 31d having a space between each other in the lateral direction are formed by joining them via. Ink flow paths 31a, 31b, 31c, 31d
Has an elongated shape with a rectangular cross section, and has side walls 2a, 2b, 2
c, 2d, and 2e extend over the entire length of the flow path, are deformable in the direction perpendicular to the flow axis and the polarization direction, and change the ink pressure in the flow path. Metal electrodes 11a, 11b, 1 for applying a driving electric field are formed on the surfaces of the side walls 2a, 2b, 2c, 2d, 2e.
1c and 11d are formed, and the metal electrodes 11a and 11d are formed.
The surfaces of b, 11c, 11d, and 11e are surface-treated to prevent corrosion by ink.

In the array, for example, when the ejection device 31b is selected according to predetermined print data, the metal electrode 1
A driving electric field is applied between each of the metal electrodes 1a and 11b and the metal electrodes 11c and 11d. At this time, since the driving electric field direction and the polarization direction are orthogonal to each other, the side wall 2b and the side wall 2c are deformed toward the inside of the ink flow path 31b by the piezoelectric thickness sliding effect. This deformation reduces the volume in the ink flow path 31b and increases the ink pressure, and ink droplets are ejected from an orifice (not shown). Further, when the application of the driving electric field is stopped, the side wall returns to the position before the deformation, so that the ink pressure in the flow channel is lowered, and the ink is supplied from the ink supply unit (not shown) into the flow channel.

The array is manufactured by the following manufacturing method. As shown in FIG. 13, the piezoelectric ceramic plate 1 polarized in the direction of the arrow 51 is formed with the parallel grooves 3 forming the flow path having the above-described shape by grinding or the like by rotating the diamond cutting disk. . The metal electrode is formed on the surface of the groove 3 by sputtering or the like. A cover plate 21 is bonded to the groove-side upper surface 4a of the piezoelectric ceramic plate 1. Further, an orifice plate 41 having an orifice 42 provided at a position corresponding to the position of the flow path is bonded to the end surface 4b of the groove of the piezoelectric ceramic plate on the ink ejection side.

[0006]

However, in the above-mentioned conventional liquid droplet ejecting apparatus, it is necessary to perform fine groove processing in order to form the ink flow path in the piezoelectric transducer in the manufacturing process, and the degree of integration of the ink liquid droplets is high. When the gap between the adjacent ink flow paths is reduced in order to improve the above, it is difficult to process the groove of the piezoelectric ceramics, resulting in a problem that the processing cost is significantly increased.

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 with reduced manufacturing cost.

[0008]

In order to achieve this object, an ink ejecting apparatus of the present invention comprises an actuator wall at least a part of which is made of a polarized piezoelectric material, and a non-activator wall having no piezoelectric effect. A plurality of ejection channels composed of sidewalls alternately arranged and electrodes formed on the actuator wall for generating a driving electric field in the piezoelectric material by applying a voltage. The actuator wall is configured as a pressure generating means for ejecting ink from each of the two adjacent ejection channels.

The electrode has a steep rise,
In addition, a voltage pulse with a gradual fall may be applied.

Further, a voltage pulse having a gentle rise and a sharp fall may be applied to the electrode.

The actuator wall is made of a piezoelectric material polarized in the standing direction of the wall surface.
The electrodes may be provided on both side surfaces of each actuator wall so as to cover the wall surface from the end in the upright direction to the substantially central portion.

The voltage pulse may be applied to the electrodes while alternately switching the application direction of the voltage pulse to eject ink independently from each of the two adjacent ejection channels. .

[0013]

In the ink ejecting apparatus according to the first aspect of the present invention having the above structure, a plurality of ejecting channels are formed, and at least one of the ejecting channels is made of a piezoelectric material whose one side wall is polarized. An actuator wall having a portion formed therein and another actuator wall having no piezoelectric effect are formed on the other side, and an electrode for generating a driving electric field in the piezoelectric material by applying a voltage is formed on the actuator wall. The actuator wall is configured as a pressure generating means for both adjacent two ejection channels, and is driven by receiving a driving electric field from the electrodes to eject ink from each of the two ejection channels.

In the ink ejecting apparatus according to the second aspect, the voltage pulse whose rising edge is steep and whose falling edge is gentle is applied to the electrode. Therefore, when the voltage pulse is applied to the actuator wall, the actuator wall is promptly deformed to rapidly increase the pressure in one of the two adjacent ejection channels to eject ink. At that time, a negative pressure is generated in the other injection channel,
Ink is filled accordingly. After the ink ejection, the actuator wall returns to its original shape, and the ejection channel that ejected the ink replenishes the ink with a negative pressure. However, since the actuator wall is slowly restored, a large pressure is not generated in the other ejection channel filled with the ink, and unnecessary ink is not ejected from the channel.

In the ink jet apparatus according to the third aspect of the invention, the voltage pulse whose rising is gentle and whose falling is sharp is applied to the electrodes. Therefore, when the voltage pulse is applied to the actuator wall, the actuator wall is deformed to generate a negative pressure in one of the two adjacent ejection channels, and the ink is filled accordingly. At this time, the other ejection channel is pressurized, but the actuator wall is deformed slowly, so that a large pressure is not generated in the other ejection channel and unnecessary ink is not ejected from the channel. Further, after the ink is filled, the actuator wall immediately returns to its original shape, and the pressure in the ejection channel filled with the ink is rapidly increased to eject the ink. At that time, a negative pressure is generated in the other ejection channel, and ink is replenished correspondingly.

In the ink ejecting apparatus according to the fourth aspect, the actuator wall is formed of a piezoelectric material polarized in the rising direction of the wall surface, and the electrodes are provided on both side surfaces of each actuator wall. It is provided so as to cover the end portion in the direction to the substantially central portion. Therefore, the shear mode type ink jet device is configured with a simple configuration.

In the ink ejecting apparatus according to the present invention, the voltage pulse is applied to the electrodes while alternately switching the application direction of the voltage pulse, whereby ink is ejected from each of the two adjacent ejection channels. To fire independently.

[0018]

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

As shown in FIG. 1, the actuator plate 101 polarized in the direction of the arrow 105 is made of a lead zirconate titanate (PZT) piezoelectric ceramic material.

The actuator plate 101 is cut with a diamond blade or the like to have a depth of 400, for example.
A plurality of grooves 117 having a width of 240 μm and a width of μm are formed. Further, the partition wall 111, which is the side surface of the groove 117, has a width of 80 μm, for example. The groove 117 is, for example, a groove having a length of 10 mm and provided in parallel with each other.
It is formed so as to form a shallow parallel groove 115 in the vicinity. As shown in FIG. 2, electrodes 124 and 125 are formed on the inner surfaces of the groove 117 and the shallow groove 115 by sputtering or the like. The electrode 124 is formed on only the upper half of the side surface of the groove 117, while the electrode 125 is formed on the entire side surface and bottom surface of the shallow groove 115. At this time, each electrode 125 is electrically connected to the adjacent electrode 124. The arrow 105 in the figure corresponds to the standing direction of the wall surface in the present invention.

Then, as shown in FIG. 3, the shallow groove 11 is formed.
A divided groove 118 having a width narrower than that of the shallow groove 115 and deeper than half the depth of the groove 117 is cut by a diamond blade or the like in the widthwise central portion of the groove 5. In this embodiment, a dividing groove 118 having a width of 80 μm is formed. Due to the shallow groove 115, the electrode 125 is divided at the central portion, and each of the divided portions becomes a drive electrode 126 that is electrically connected to the adjacent electrode 124 in a one-to-one correspondence. The width of the cavity 119 is 240 μm.

Next, as shown in FIG. 4, the height is 400 μm.
m, width 80 μm, length 9 mm of sidewall 112 and sidewall 1
A resin cavity plate 102 having a cavity 119 sandwiched between 12 is manufactured by an injection molding method.

Then, as shown in FIG. 5, the actuator plate 101 and the cavity plate 102, the side wall 112 in the central portion of the groove 117, and the cavity 1 are formed.
The partition wall 111 is adhered to the central portion of 19 via an adhesive layer 120 (FIG. 6) made of an epoxy resin. At this time, the cavity plate 1 is formed in the shallow groove 115.
02 side wall 112 is fitted and sealed. Also, groove 1
Reference numeral 17 denotes a plurality of ink liquid chambers 1 which are laterally spaced from each other.
21. On the other hand, the portion where the groove 117 gradually becomes shallower to the shallow groove 115 becomes the ink supply port 130.

In the actuator plate 101, as shown in FIG. 6, the ink liquid chamber 121 is formed on the end surface 113 side where the shallow groove 115 is not formed in the channel direction.
Plate 131 having nozzles 132 at positions corresponding to
Are bonded with an epoxy adhesive (not shown). This nozzle plate is made of a plastic such as polyalkylene (for example, ethylene) terephthalate, polyimide, polyetherimide, polyetherketone, polyethersulfone, polycarbonate, or cellulose acetate.

As a result, the ink ejecting apparatus 100 having the ink liquid chamber 121, the partition wall 111 of which at least a part is made of piezoelectric ceramics, and the electrode 124 is manufactured.

A substrate 141 having a pattern electrode 142 formed thereon is joined to the lower portion of the actuator plate 101 with an epoxy resin adhesive not shown. After joining, as shown in FIG. 6, the drive electrode 126 in the groove 117 and the pattern electrode 142 on the substrate 141 are electrically coupled by a known method such as a wire bonding method.

Next, the configuration of the control unit of this embodiment will be described with reference to FIG. 7 which is a block diagram of the control unit. As shown in the figure, the patterns 142 on the substrate 141 are individually connected to the LSI chip 51, and
2, 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 determines which nozzle 132 should eject an ink droplet from the data appearing on the data line 53, based on the continuous clock pulses supplied from the clock line 52. Then, the LSI chip 51
Is applied to the drive electrode pattern 141 that is electrically connected to the electrode 124 in the driven ink liquid chamber 121, and
Is applied to the ink liquid chamber 12 other than the ink liquid chamber 121.
The ground line 55 is connected to the drive electrode pattern 141 that is electrically connected to the electrode 124 in the first electrode 1 and grounded.

Next, the ink ejecting apparatus 10 according to the present embodiment.
The operation of 0 will be described with reference to FIGS. In order to eject ink droplets from the ink liquid chamber 121c shown in FIG.
As shown in FIG. 1 (a), from the ground to the voltage V, for example, a rising portion 107 for 3 μs, a holding portion 108 for holding the voltage V for 15 μs, and 15 μs for the voltage V to the ground.
The voltage pulse 103 including the falling portion 109 is applied (here, applying a voltage to a certain electrode 124 means applying the voltage pulse 103 to the electrode 124 and grounding the electrode 124 which is not instructed). Then, at the rising portion 107, an electric field in the direction of arrow 106 is generated in the partition wall 111 as shown in FIG.
b is rapidly moved to the left in the figure in a V shape due to the piezoelectric thickness sliding effect. Then, the volume of the ink liquid chamber 121c decreases, and the pressure in the ink liquid chamber 121c including the vicinity of the nozzle 132c rapidly increases. As a result, the ink in the ink liquid chamber 121c becomes an ink droplet and is ejected from the nozzle 132c. At that time, the adjacent ink liquid chamber 1
A negative pressure is generated in 21d, and the ink is filled accordingly.

Next, after the driving voltage is held only during the holding portion 108, the driving voltage is changed to the falling portion 10.
As shown in FIG. 9, when it goes down to the ground, the ink liquid chamber 121c
Is gradually increased from the reduced state to the natural state, and ink is supplied into the ink chamber 112c from an ink supply source (not shown) to the ink liquid chamber 121c through a manifold (not shown). At this time, the volume of the ink liquid chamber 121d adjacent to the partition wall 111b decreases, but the movement of the partition wall 111b at the falling portion 109 is slower than that at the rising portion 107, so that the ink is ejected from the nozzle 132d. No droplets are ejected.

Next, in the case of ejecting ink droplets from the ink liquid chamber 121d having the partition wall 111b as a common pressure generating means, as shown in FIG. 11 (a) with respect to the electrode 124d in the ink liquid chamber 121d. A voltage pulse 103 including a rising portion 107 of 3 μs, a holding portion 108 holding the voltage V of 15 μs, and a falling portion 109 of 15 μs from the voltage V to the ground is applied from the ground to the voltage V as shown in FIG. Applying a voltage to an electrode 124 causes the voltage pulse 103 to be applied to that electrode 124.
Is applied, and the unindicated electrode 124 is grounded). Then, at the rising portion 107, as shown in FIG.
As shown in FIG. 5, an electric field in the direction of arrow 206 is generated in the partition wall 111, and the partition wall 111b rapidly moves in the reverse "-" shape in the right direction in the figure due to the piezoelectric thickness sliding effect. Then, the volume of the ink liquid chamber 121d decreases, and the pressure in the ink liquid chamber 121d including the vicinity of the nozzle 132d rapidly increases. As a result, the ink in the ink liquid chamber 121d becomes an ink droplet and is ejected from the nozzle 132d. At that time, a negative pressure is generated in the adjacent ink liquid chamber 121c, and the ink is filled by that amount.

Next, when the driving voltage is held during the holding portion 108 and then falls to the ground like the falling portion 109, the volume of the ink liquid chamber 121d is naturally reduced from the reduced state. Gradually increase to the state,
Ink is supplied to the ink liquid chamber 121d from an ink supply source (not shown) in the ink chamber 112d through a manifold (not shown). At this time, adjacent to the partition wall 111b,
Although the volume of the ink liquid chamber 121c decreases, the movement of the partition wall 111b at the falling portion 109 is slower than that at the rising portion 107, so the nozzle 13
No ink droplet is ejected from 2c.

Ink liquid chamber 1 having a common partition wall 111b
21c and the ink liquid chamber 121d, when ink droplets are ejected, after applying the voltage pulse 103 of FIG.
A voltage pulse 203 as shown in FIG. 11B, which is shifted by 5 μs, may be applied to the ink liquid chamber 121d.

Further, in the above-described embodiment, first, the drive voltage is applied in the direction in which the volume of the ink liquid chamber 121 is reduced to eject ink droplets, and then the application of the drive voltage is stopped to move the ink liquid chamber 121. Ink liquid chamber 1 by increasing the volume to the natural state
Although the ink was supplied to the ink tank 21, the drive voltage was first applied so that the volume of the ink liquid chamber 121 was increased to supply the ink to the ink liquid chamber 121, and then the application of the drive voltage was stopped. The volume of the liquid chamber 121 may be reduced from the increased state to the natural state, and the ink in the ink liquid chamber 121 may be ejected as ink droplets. In this case, the rising portion 107 of the voltage pulse 103 is set to, for example, 15 μs, The falling portion may be 5 μs.

As described above, in the ink ejecting apparatus 100 of this embodiment, the partition wall 111 is formed, the actuator plate 101 made of a piezoelectric ceramic material, and the resin cavity plate 10 having the side wall 112 formed by the injection molding method.
2 has a configuration in which the partition walls 111 and the side walls 112 are alternately arranged, so that the groove processing width of the actuator plate 101 becomes larger than the width of the ink liquid chamber 121. In order to reduce the distance between adjacent ink flow paths in order to improve the degree of integration of droplets,
As compared with the conventional method, the groove machining is facilitated, the number of processed portions is reduced, and the machining cost can be reduced accordingly.

[0035]

As described above, in the ink ejecting apparatus according to the present invention, the arrangement of the actuator wall can be doubled as compared with the conventional arrangement, so that the processing for forming the actuator wall is easy and the processing cost is reduced. It can be reduced. Therefore, mass productivity is excellent and reliability is improved.
As a result, it is possible to further improve the degree of integration of ink droplets.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a manufacturing process of the ink ejecting apparatus.

FIG. 3 is a perspective view showing a manufacturing process of the ink ejecting apparatus.

FIG. 4 is a cross-sectional view showing a manufacturing process of the ink ejecting apparatus.

FIG. 5 is a perspective view showing a configuration of an ink ejecting apparatus according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a manufacturing process of the same ink ejecting apparatus.

FIG. 7 is a block diagram showing a control unit of the ink ejecting apparatus according to the embodiment of the invention.

FIG. 8 is an explanatory diagram showing an operation of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an operation of the ink ejecting apparatus.

FIG. 10 is an explanatory diagram showing an operation of the ink ejecting apparatus.

FIG. 11 is an explanatory diagram showing drive voltage waveforms according to an embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a conventional ink ejecting apparatus.

FIG. 13 is a perspective view showing a configuration of a conventional ink ejecting apparatus.

[Explanation of symbols]

 100 Ink Ejection Device 101 Actuator Plate 102 Cover Plate 103 Voltage Pulse 111 Partition Wall 112 Side Wall 121 Ink Liquid Chamber 124 Electrode

Claims (5)

[Claims] 1. A plurality of ejection channels each having side walls formed by alternately arranging an actuator wall, at least a part of which is formed of a polarized piezoelectric material, and a non-actuator wall having no piezoelectric effect. An electrode formed on the actuator wall for generating a driving electric field in the piezoelectric material by applying a voltage, and one actuator wall for ejecting ink from two adjacent ejection channels, respectively. An ink ejecting apparatus configured as a generating unit. 2. The ink jet apparatus according to claim 1, wherein a voltage pulse having a steep rise and a gradual fall is applied to the electrode. 3. The electrode has a gentle rising,
The ink ejecting apparatus according to claim 1, wherein a voltage pulse having a sharp fall is applied. 4. The actuator wall is formed of a piezoelectric material polarized in a standing direction of a wall surface thereof, and the electrodes are provided on both side surfaces of each of the actuator walls, and are substantially centered from an end portion in the standing direction of the wall surface. The ink ejecting apparatus according to claim 1, wherein the ink ejecting apparatus is provided so as to cover up to the portion. 5. The ink is independently ejected from each of the two adjacent ejection channels by applying the voltage pulse to the electrode while alternately switching the application direction of the voltage pulse. The ink ejecting apparatus according to claim 2 or 3.