JPH11348274A - Ink-jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an ink quality change because of an electrode reaction in an ink-jet recording head in which piezoelectric ceramics diaphragms are deformed in accordance with a voltage impressed to signal electrodes formed at inner walls of a plurality of channels separated by the diaphragms, thereby selectively discharging an ink filled in the channels through ink discharge openings communicating with the channels. SOLUTION: A plurality of parallel channels are set alternately as an ink discharge channel 9 filled with an ink and a non-discharge channel 19 not filled with the ink. An impression voltage to signal electrodes formed at inner walls of the discharge channels 9 is always kept at the same potential, while an impression voltage to signal electrodes at inner walls of the adjacent non- discharge channels 19 is changed, whereby diaphragms of the discharge channels are deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a plurality of parallel channels separated by a partition made of piezoelectric ceramics, and the partition is formed in accordance with a voltage applied to a signal electrode formed on an inner wall of the channel. The present invention relates to an ink jet recording head which deforms and selectively protrudes ink filled in the channel from a nozzle connected to the channel with the deformation. In particular, the quality of the ink is changed by a voltage applied to a signal electrode. It is characterized by a configuration that prevents

[0002]

2. Description of the Related Art Conventionally, an ink jet recording head utilizing the shear mode deformation of a piezoelectric element as an ink ejection principle has been considered as disclosed in Japanese Patent Application Laid-Open No. 63-252750. As shown in FIG. 5 (a), this structure mainly includes an actuator member 1, a cover plate 3, a nozzle plate 2, and a printed wiring board 6 made of piezoelectric ceramics.

The actuator member 1 is made of a plate-shaped piezoelectric ceramic, and has a plurality of mutually parallel channels 9 formed by cutting with a diamond blade or the like on the surface thereof. The partition wall of the channel 9 is polarized in the groove depth direction.

The channels 9 have the same groove width, the same length, and are parallel, and the depth is gradually reduced as approaching the rear end face of the actuator member 1 as shown in FIG. Channel shallow groove region 1 near the rear end face
0 is formed. The signal electrodes 4 for deforming and driving the channels are formed on the upper halves of both sides of each channel 9 by vapor deposition or the like. Similarly, in the channel shallow groove region 10, the signal electrodes 4 are formed on the side and bottom surfaces by vapor deposition or the like, whereby the signal electrodes 4 formed on both side surfaces of each channel 9 are formed on the bottom surface of the channel shallow groove region 10. 5C, the two side walls of the channel 9 are used as one signal electrode.

[0005] The cover sheet 3 is formed of a ceramic material or a resin material. The cover sheet 3 has an ink supply port 8 and a manifold 7 formed by grinding or cutting. Then, the processing-side surface of the channel 9 of the actuator member 1 and the processing-side surface of the manifold 7 of the cover plate 3 are adhered with an epoxy-based adhesive 12. In this way,
In the ink jet head, a channel groove is formed as a plurality of ink flow paths having the same space in the horizontal direction by covering the upper surface of the channel 9. The channels 9 have an elongated shape with a rectangular cross section, and all the channels 9 are filled with ink from the ink supply ports 8.

Further, as shown in FIG. 5A, a nozzle plate 2 is disposed on the end surfaces of the actuator member 1 and the cover plate 3. The nozzle plate 2 is formed of a plastic such as polyimide, polyetherimide, polyetherketone, polyethersulfone, or polycarbonate. The nozzle plate 2 uses an epoxy adhesive 12 to form ink on the actuator member 1 and the cover plate 3. After attaching to the discharge surface side, the center of each channel 9 is positioned by a microscope or the like, and the nozzle 5 is processed using an apparatus such as an excimer laser.

A printed wiring board 6 is adhered to the surface of the actuator member 1 opposite to the channel 9 with an epoxy adhesive or the like. The conductive pattern 11 is formed on the printed wiring board 6 at a position corresponding to the position of each channel 9. The conductive pattern 11 and the signal electrode 4 formed on the bottom surface of the channel shallow groove region 10 are connected by wire bonding 13. Then, by selectively applying a voltage to the signal electrode 4, ink is selectively ejected from a predetermined nozzle 5.

[0008]

In the above-mentioned conventional structure, when a voltage is applied to the signal electrode during ink ejection, the signal electrode formed on the channel side wall is always in contact with the ink, and Is in communication with the ink in the adjacent channel, a potential difference is generated between the discharging channel and the adjacent non-discharging channel, particularly when ink with low resistance (for example, aqueous ink) is used. In some cases, the ink was deposited and could not be discharged.

[0009]

According to the present invention, there is provided an ink jet recording head comprising a plurality of channels parallel to each other.
A channel filled with ink, and at least a channel adjacent to the ejection channel in which the ink ejection port is formed,
A non-ejection channel not filled with ink, the voltage applied to the signal electrode formed on the inner wall of the ejection channel is always the same, and the voltage applied to the signal electrode on the inner wall of the non-ejection channel adjacent to the ejection channel Is changed to deform the partition wall of the discharge channel.

According to this configuration, since the potential of the signal electrode provided on the inner wall of the discharge channel for discharging ink filled therein is always set to the same potential, ink solid precipitates due to the electrode reaction. Things will be gone.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. Note that components that are substantially the same as those in the conventional example shown in FIG. 5 are denoted by the same reference numerals.

(Embodiment 1) Regarding the channel formation and configuration, the conventional configuration was such that ink could be ejected from all the channels 9, but for the purpose of eliminating the electrode reaction, in this embodiment, Ink ejection is performed only on a predetermined channel (even channel in this embodiment), and at least a channel adjacent to the predetermined channel (odd channel in this embodiment) is a non-ejection channel that is not filled with ink.

In the configuration, all channels are conventionally the same length, but in the present embodiment, as shown in FIG. 1A, the odd channel 19 is shorter than the even channel 9 and the even channel 9 is shorter. 9 rear end is odd channel 1
9 is formed by cutting or the like on the surface of the plate-shaped actuator member 1 so as to protrude from the rear end portion by a predetermined length protruding portion 15.

A projection 15 projecting from the rear end of the odd channel 19 of the even channel 9 by a predetermined length.
The groove corresponding to the above is processed by a dicer so as to penetrate the even channel from the back side of the channel processing surface of the actuator member 1 to the even channel in the direction perpendicular to the groove direction of the channel 9 by using a dicer. An ink supply groove 16 capable of supplying ink is formed at 9. According to this configuration, it is possible to easily supply the ink to only the channel 9.

On the other hand, the cover plate 3 has no ink supply port as in the prior art, and partitions the channel 9 with a plate that covers the entire surface of the actuator member 1. Thus, the even-numbered channel 9 is filled with ink and has the nozzles 5 and serves as a discharge channel for performing ink discharge. The odd-numbered channel 19 is not filled with ink and has no nozzles 5 and performs ink discharge. This is a non-ejection channel without any problem.

Next, the formation of the signal electrode 4 will be described.
As shown in FIGS. 3A and 3B, the signal electrodes 4 on the inner wall of the even-numbered channel 9 are connected to the signal electrodes 4 on both wall surfaces of the channel 9 in the channel shallow groove region 10 in the conventional manner. Leave in the state. On the other hand, the odd-numbered channel 19 has a portion where the signal electrodes 4 on both wall surfaces are connected in the channel shallow groove region 10 behind the signal electrode 4 formed on the side wall of the channel for the purpose of separately driving the deformation of both walls. Dicing is performed by using a thin dicer blade 18 having a width of 1/3 or less of the channel groove width so as to be electrically independent for each wall. As a result, the signal electrodes 4 on both walls of the odd-numbered channel 19 can be separated by the dividing groove 17, and a separately driven divided signal electrode 20 can be formed. The connection between the signal electrodes 4 and the divided signal electrodes 20 and the printed wiring board 6 is performed by conventional wire bonding.

Regarding the head drive, as shown in FIG.
Discharge channel (even channel) 9 for discharging ink
Signal electrode 4 is always set to 0 V for all channels. In the ink ejection, a predetermined voltage is applied to the signal electrodes on the ejection channel wall side of the signal electrodes formed on the inner walls of the non-ejection channels (odd channels) 19 of both walls in order to deform and drive both walls of the even channel 9 where ejection is performed. The ink is ejected from the nozzles 5 of the even-numbered channels 9 by deforming both walls. At this time, since the signal electrode of the odd channel 19 is not in contact with the ink, no potential difference occurs in the ink, and no electrode reaction occurs.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention. In this embodiment, the odd channel 19 and the even channel 9 have the same length, but the ejection channel A groove 18 is formed at the rear end of the even-numbered channel 9 by a predetermined depth from the rear end of the odd-numbered channel 19.

The deep groove 18 of the even channel 9 extends in a direction perpendicular to the longitudinal direction of the even channel 9 from the back side of the channel processing surface of the actuator member 1.
Grooves are formed with a dicer so that the ink supply grooves 16 can be supplied to the respective even-numbered channels 9.
To form With this configuration, the channel 9 can be easily obtained.
It is possible to provide a configuration in which ink can be supplied only to ink.

[0020]

As described above, according to the ink jet recording head of the present invention, there can be obtained an ink jet recording head in which a potential difference does not occur between a discharge channel and a non-discharge channel, and no ink solid is deposited due to an electrode reaction.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an inkjet recording head according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a nozzle arrangement and a signal electrode arrangement of the ink jet recording head.

FIG. 3A is a perspective view for explaining a method of forming an odd-numbered channel signal electrode of the inkjet recording head. FIG. 3B is a plan view showing wiring after the odd-numbered channel signal electrode of the inkjet recording head is formed.

4A is a side sectional view of an ink jet recording head according to a second embodiment of the present invention. FIG. 4B is a longitudinal sectional view showing the arrangement of nozzles and signal electrodes of the ink jet recording head.

5A is an exploded perspective view of a conventional inkjet recording head. FIG. 5B is a side sectional view of the inkjet recording head. FIG. 5C is a longitudinal sectional view showing the arrangement of nozzles and signal electrodes of the inkjet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator member 2 Nozzle plate 3 Cover plate 4 Signal electrode 5 Nozzle 6 Printed wiring board 7 Manifold 8 Ink supply port 9 Ejection channel (even channel) 10 Channel shallow groove area 11 Conductive pattern 15 Projection 16 Ink supply groove 17 Division groove 18 Dicer blade 19 Non-ejection channel (odd number channel) 21 Deep groove

Claims (4)

[Claims] The present invention has a plurality of parallel channels separated by a piezoelectric ceramic partition, and the partition is deformed in accordance with a voltage applied to a signal electrode formed on an inner wall of the channel. An ink jet recording head for selectively ejecting ink filled in the channel from an ink ejection port communicating with the channel, wherein the ink is filled in a plurality of channels parallel to each other, and the ink ejection port is A channel at least adjacent to the ejection protruding channel in which is formed is a non-ejection channel not filled with ink, and a voltage applied to a signal electrode formed on the inner wall of the ejection channel is always set to the same potential. Change the voltage applied to the signal electrode on the inner wall of the adjacent non-ejection channel The ink jet recording head is characterized in that the partition walls of the discharge channel are deformed. 2. The ink jet recording head according to claim 1, wherein a plurality of parallel channels are alternately used as the ejection channel and the non-ejection channel. 3. The discharge channel has a length longer than a length of the non-discharge channel such that a rear end of the discharge channel protrudes by a predetermined length from a rear end of the non-discharge channel. 2. The ink jet recording head according to claim 1, wherein ink is supplied into the ejection channel from a protruding portion of the ejection channel. 4. A deep groove deeper than a rear end of the non-ejection channel is formed at a rear end of the discharge channel formed in a plate-shaped piezoelectric ceramic material, and a deep groove is formed on a back surface of the piezoelectric ceramic material. 2. The ink jet recording head according to claim 1, wherein a groove extending in a direction perpendicular to the longitudinal direction and reaching the deep groove portion is formed, and ink is supplied into each of the ejection channels via the groove.