JPH09207331A - Inkjet recording head - Google Patents

Abstract

(57) Abstract: Having a plurality of parallel channels separated by a partition of a piezoelectric ceramic, the partition is deformed according to a voltage to a signal electrode formed on the partition of the channel, The present invention relates to an inkjet recording head that selectively ejects ink filled in a channel from an ink ejection port. It is possible to eliminate an electrode reaction of ink between signal electrodes of adjacent channels, and particularly to form an electrode protective film. Provides a configuration that is not needed. SOLUTION: An ink supply port 7 that supplies ink commonly to a plurality of channels 8 is provided at the other end of the channel 8 on the side opposite to the ink discharge port 5, and the vicinity where the ink supply port 7 is formed is provided. Signal electrode 4 on the partition of each channel except
And a signal voltage is applied to the signal electrode 4 through a via hole 14 formed in the cover plate 3 provided so as to cover the channel 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a plurality of channels that are parallel to each other and are separated by partition walls of piezoelectric ceramics, and the partition walls are formed according to a voltage applied to a signal electrode formed on the partition walls of the channels. The present invention relates to an ink jet recording head which is deformed, and the ink filled in the channel is selectively projected from a nozzle communicating with the channel by the deformation.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 63-2527
As disclosed in Japanese Patent Publication No. 50, an ink jet recording apparatus using a shear mode deformation of a piezoelectric element as an ink ejection principle has been considered. As shown in FIG. 4, this structure is largely composed of an actuator member 1 made of piezoelectric ceramics, a nozzle plate 2, a cover plate 3, and a printed wiring board 6. The actuator member 1 has a plurality of channels 8 formed in parallel with each other and cut by a diamond plate or the like. The partition walls 10 between the channels 8 are polarized in the groove depth direction.

The channels 8 are of the same depth,
In addition, as shown in FIG. 5, the depth of the channel 8 is gradually shallower in the vicinity of the rear end face 11 of the actuator member 1 as it approaches the rear end face, and the channel shallow groove 16 is formed in the vicinity of the rear end face 11. Has been done. And
The signal electrodes 4 are formed on the upper half of both side surfaces of each channel 8 by sputtering or vapor deposition. Similarly, in the shallow channel groove 16, the signal electrode 4 is also formed on the side surface and the bottom surface by sputtering or vapor deposition. As a result, the signal electrodes 4 formed on both side surfaces of the channel 8 are electrically connected by the signal electrodes 4 formed on the bottom surface of the channel shallow groove 16.

Next, the cover plate 3 is formed of a ceramic material, a resin material, or the like, and the cover plate 3 is provided with an ink supply port for commonly supplying ink to each channel 8 by grinding or cutting. 7 are formed. Then, the surface of the actuator member 1 on the processed side of the channel 8 and the surface of the cover plate 3 on the processed side of the ink supply port 7 are bonded by the epoxy adhesive 12 (FIG. 5).

In this way, the ink jet head is formed with the channels 8 as a plurality of ink flow paths which cover the upper surfaces of the channel grooves and have the same intervals in the lateral direction. The channel 8 has an elongated shape with a rectangular cross section, and all channels are constantly filled with ink from a common ink supply port 7.

As shown in FIG. 4, the actuator member 1
The nozzle plate 2 is bonded to the end surface of the cover plate 3 so that the nozzle 5 is located at a position corresponding to the position of each channel 8. The nozzle plate 2 is formed of a plastic such as polyimide, polyetherimide, polyetherketone, polyethersulfone, and polycarbonate.

A printed wiring board 6 is adhered to the surface of the actuator member 1 opposite to the channel 8 with an epoxy adhesive or the like. Conductive patterns 9 are formed on the printed wiring board 6 at positions corresponding to the positions of the channels 8. The conductive pattern 9 and the signal electrode 4 on the bottom surface of the channel shallow groove 16 are connected by wire bonding 13.

[0008]

In this conventional structure, the channel partition in the cover plate is deformed so that not only the portion required for ejecting the ink but also the printed wiring board at the rear end of the channel are connected. Moreover, it was necessary to form the signal electrode by evaporation for a long time. Therefore, the signal electrode of the ink supply port is connected to the signal electrode of the adjacent channel through the ink in the ink supply port 7, and the component dissolved or dispersed in the ink by the voltage between the signal electrodes of the adjacent channels is the electrode. Since the reaction causes agglomeration or decomposition, it is necessary to attach an electrode protective film serving as an insulating film on the surface of the signal electrode.

[0009]

In the ink jet recording head of the present invention, an ink supply port for supplying ink to a plurality of channels is provided at the other end of the channel opposite to the ink ejection port, and the ink supply is performed. The feature is that a signal electrode is formed on the partition wall of each channel except for the vicinity where the mouth is formed.Because the signal electrode is not formed in a portion adjacent to the adjacent channel through the ink, It is possible to eliminate the electrode reaction of ink that occurs between the signal electrodes of the channels, and in particular, it is not necessary to form an electrode protective film.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention has a plurality of channels that are parallel to each other and are separated by partition walls of piezoelectric ceramics, and a voltage to a signal electrode formed on the partition walls of the channels. According to the deformation of the partition wall, the ink filled in the channel is formed at one end of the channel according to the deformation,
An ink jet recording head for selectively projecting from an ink discharge port communicating with a channel, wherein an ink supply port for supplying ink commonly to a plurality of channels is provided at the other end of the channel on the opposite side of the ink discharge port. It is characterized in that a signal electrode is formed on the partition wall of each channel except the vicinity where the ink supply port is formed, and a signal electrode is formed near the ink supply port where an ink electrode reaction occurs. Therefore, the electrode reaction of ink between the signal electrodes of the adjacent channels can be eliminated, and in particular, the formation of the electrode protective film is not necessary.

The invention according to claim 2 of the present invention is characterized in that the voltage is applied to the signal electrode formed on the partition wall of each channel through a via hole penetrating the cover plate covering each channel. The inkjet recording head according to claim 1, wherein a signal voltage can be applied to the signal electrode of each channel with a simple configuration. (Embodiment) An embodiment of the present invention will be described with reference to FIGS. The same components as those in the conventional example shown in FIGS. 4 and 5 are denoted by the same reference numerals.

First, on one surface of the piezoelectric ceramic actuator member 1 having a thickness of about 1 mm, the thickness is several tens of μm.
The photosensitive resist film 17 of No. 1 is formed by a method such as normal hot roller lamination, and then the above-mentioned resist film 17 is formed on the piezoelectric ceramic member 1.
By using a cutting means such as a dicing saw, as shown in FIG.
A shallow groove 18 having a width of μm and a depth of about 20 μm is formed. The shallow groove 18 is processed to the rear end surface of the ink supply port 7 of the cover plate 3 with the same width and the same depth according to the nozzle pitch and the number of nozzles.

Further, a channel 8 having a groove width of 70 to 100 μm and a depth of about 300 to 500 μm is formed in the center of the shallow groove 18 by a cutting means such as a dicing saw (b in FIG. 3). This channel 8 is similarly processed up to the rear end surface of the ink supply port 7. After performing such processing, a masking means such as a metal mask is joined to the piezoelectric ceramic wafer to signal the partition wall 10 of the channel 8 other than the vicinity of the portion where the ink supply port 7 of the cover plate 3 is located. After the electrodes 4 are formed, the piezoelectric ceramic wafer is held in the vacuum deposition apparatus at an angle to hold the shallow groove 18 and the upper half region of the channel partition 10. The signal electrode 4 is formed only on the actuator section of (3) in FIG.

Next, the resist film 17 is lifted off using a solvent such as acetone, so that the signal electrodes 4 formed on the inner walls of the respective channels function as driving means for the channel walls for ejecting ink. (FIG. 3d). Next, the cover plate 3 attached to the actuator member 1 is attached to the cover plate 3 by a conventional HIC technique as shown in FIG.
As shown in FIG. 5, a via hole 14 penetrating in the vertical direction is formed. The arrangement of the via holes 14 differs depending on the number of nozzles and the nozzle pitch, but it is sufficient if the via holes 14 of adjacent nozzles can be connected by a part of the signal electrode formed by vapor deposition on the side wall surface of the channel. It's better. Further, the diameter of the via hole 14 is the maximum diameter, that is, the channel groove width + 1/2 channel side wall width, preferably less than or equal to the channel groove width.

FIG. 2 shows how the cover plate 3 is attached to the actuator member 1. The epoxy adhesive 12 is applied to the protrusion region on the top of the actuator side wall of the actuator member 1 by screen printing or transfer method with a thickness of several tens of μm. On the other hand, a conductive adhesive 15 for connecting with the channel top electrode is printed and applied to the via hole 14 on the surface of the cover plate 3 which is joined to the channel by screen printing, and the actuator member 1
And paste it.

At this time, when the cover plate 3 having the via hole 14 is aligned and attached to the actuator member 1, the via hole 14 coated with the conductive adhesive 15 is applied.
The opposite signal electrodes 4 formed on the inner wall of the channel.
After aligning so as to bridge, join. Then, these members are put into an oven to heat and cure the adhesive.

As a means for applying a signal to the head member formed as described above, ink is ejected by electrically connecting to a via hole pad portion on the upper surface of the cover member with a connector such as a pin grid. In this way, there is no need for a means for forming a passivation film by means of plasma-CVD or the like to cover the surface of the signal electrode that comes into contact with ink as in the conventional case, and a device such as wire bonding is also unnecessary, thereby reducing costs. It is possible to make a cheap and highly reliable shear mode type inkjet head.

[0018]

According to the ink jet recording head of the present invention, a large-scale apparatus for forming a protective film which has been conventionally required to protect the surface of the signal electrode formed on the inner wall of the ink channel from the ink is required. Moreover, the size of the head is further reduced, and a reliable and long-life ink jet recording head can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view in the longitudinal direction of a channel of an inkjet recording head according to an embodiment of the present invention.

FIG. 2 is a channel cross-sectional view of the ink jet recording head according to the same embodiment.

FIG. 3 is a channel cross-sectional view in a manufacturing process of the ink jet recording head according to the same embodiment.

FIG. 4 is an exploded perspective view of a conventional shear mode type inkjet recording head.

FIG. 5 is a sectional view in the longitudinal direction of the channel of the conventional inkjet recording head.

[Explanation of symbols]

 1 Actuator member 2 Nozzle plate 3 Cover plate 4 Signal electrode 5 Nozzle 6 Printed wiring board 7 Ink supply port 8 Channel 9 Conductive pattern 10 Actuator side wall (partition wall) 11 Actuator member rear end face 12 Epoxy adhesive 14 Via hole

Claims (2)

[Claims] 1. A plurality of channels which are parallel to each other and are separated by a partition wall of piezoelectric ceramic, and the partition wall is deformed in accordance with a voltage applied to a signal electrode formed on the partition wall of the channel. An ink jet recording head, wherein ink filled in the channel is formed at one end of the channel and selectively protrudes from an ink discharge port communicating with the channel, the ink jet recording head being provided on the other side of the ink discharge port. An ink jet recording head characterized in that an ink supply port for supplying ink to a plurality of channels is provided at an end portion, and a signal electrode is formed on a partition wall of each channel except the vicinity where the ink supply port is formed. 2. A plurality of channels are formed by cutting on one surface of a piezoelectric ceramics plate, and a voltage is applied to a signal electrode formed on a partition wall of each of the channels, and a cover plate covering each of the channels is applied. 2. The ink jet recording head according to claim 1, wherein the ink jet recording head is formed through a via hole penetrating through.