JPH0516364A - Ink jet head - Google Patents

Abstract

PURPOSE:To provide an ink jet head which can heat conductive ink of a small volume effectively and can easily be made highly dense. CONSTITUTION:An ink jet head is constructed as follows: a counter electrode corresponding to a nozzle and a pressure chamber 6 exciting between those counter electrodes are provided: one side of the counter electrodes in the pressure chamber 6 is taken as a common electrode 4 and a part of an ink passage 3 is constructed by the common electrode 4: unused electrode surface of a signal electrode 1 and the common electrode 4 is covered by an insulating layer 5 to obtain a required electrode area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention applies an electric current to ink,
The present invention relates to an ink jet printer of a type in which an ink boiling is generated by the flowing current and an ink droplet is ejected by a bubble generated at that time.

[0002]

2. Description of the Related Art In recent years, demands for printers have become faster, lower in noise, and in color, and ink jet printers have been drawing attention.

Ink jet printers are roughly classified into a continuous type and an on-dimmed type. Furthermore, among the on-dimed type, a Kaiser type, a stem type type, a Gould type type driven by a piezo element, a bubble is generated by heat, and its volume is increased. There is a bubble jet method that causes ink to fly by changing.

The method of generating the bubble includes a heating method using a heater and an energizing method in which a current is directly applied to the ink itself to generate heat. The present invention relates to the energizing method. The concept of the energization method is shown in U.S. Pat. No. 3,179,042 specification (1965.4.20), but there is a point that the response frequency, flight stability, power consumption, efficiency, etc. are not sufficient.

A conventional ink jet head will be described below with reference to FIGS. 5 and 6.

As shown in the figure, a heat insulating layer 12 is formed on the substrate 11.
A signal electrode 15a and a remote control electrode 15b, which are patterned corresponding to the ink ejection openings 14 formed in the nozzle plate 13, are provided on the heat insulating layer 12, and the signal electrode 15a and the remote control electrode 15b are provided between the nozzle plate 13 and the substrate 11. A partition portion 16 and an ink flow path 17 made of an insulating material that prevent interference between ink ejection ports are formed, and the substrate 11, the partition portion 16 and the nozzle plate 13 form a pressure chamber 18. An arrow a indicates a line of electric force passing through the conductive ink between the signal electrode 15a and the remote control electrode 15b, and a volume portion indicated by A is a distance g between both electrodes of the signal electrode 15a and the remote control electrode 15b. 2 shows a current passing portion of a conductive ink having a width h and an electrode thickness i. A vapor bubble generated by self-heating of the conductive ink in the current passage portion A due to the current flowing along the line of electric force a causes a pressure change in the pressure chamber 18, and the conductive ink ejected accordingly. It is a drop.

The operation of the ink jet head having the above structure will be described below.

When a voltage is applied to an arbitrary signal electrode 15a by a signal generator (not shown), an electric force is applied at the current passing portion A of the conductive ink having an arbitrary volume resistivity as shown in FIGS. Line a is generated with respect to the common electrode 15b, and current flows along this line of electric force a. Therefore, the conductive ink in the current passing portion A self-heats due to I ² R,
Finally, boiling starts and bubbles (not shown) are generated.
As a result, the pressure of the conductive ink in the pressure chamber 18 is rapidly increased, and the conductive ink droplet 19 is ejected from the ink ejection port 14 and is ejected onto the recording paper (not shown) to be attached to form dots. . Of course, since the consumed conductive ink is constantly replenished from the ink flow path 17, conductive ink droplets corresponding to the signal are continuously generated, and arbitrary continuous dot formation can be performed on the recording paper. Become.

The heat insulating layer 12 was designed to effectively generate bubbles without allowing the self-heating of the conductive ink to escape to the substrate 11.

[0010]

In such a conventional ink jet head structure, the heating efficiency of the conductive ink existing between the counter electrodes composed of the signal electrode 15a and the common electrode 15b is not good. However, in order to improve the heating efficiency of the conductive ink, it is necessary to reduce the distance g between the counter electrodes and increase the electrode thickness i. However, since it is technically difficult to reduce the distance g between the opposing electrodes and increase the electrode thickness i, the yield is deteriorated, the manufacturing process is complicated, and the cost is increased. Therefore, there is a problem that the desired electrode area cannot be obtained and the ink heating efficiency cannot be improved. Further, since the signal electrode 15a and the common electrode 15b are on the same surface, there is a problem that the wiring of the conductive wire is complicated and it is difficult to increase the density.

The present invention solves the above-mentioned problems, and is capable of efficiently heating a small volume of conductive ink,
It is an object of the present invention to provide an inkjet head that facilitates high density.

[0012]

In order to achieve the above-mentioned object, the present invention is provided with conductive ink, a plurality of nozzles, a plurality of counter electrodes corresponding to the nozzles, and between the counter electrodes. A pressure chamber, an ink flow path that guides the ink to the pressure chamber, and a voltage applying device that applies a conduction voltage to the arbitrary counter electrode, and a part of the pressure chamber is formed by one wall portion of the nozzle. The counter electrode is one of the electrodes.

[0013]

According to the present invention, with the above-described structure, the distance between the signal electrode and the common electrode can be easily reduced to a desired distance, and the optimum electrode area for ink ejection can be obtained. A large increase in the efficiency of heating the ink can be obtained. In addition, since the conductive wiring is limited to the signal line, high density can be achieved.

[0014]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
The description will be made with reference to FIG. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the drawing, a signal electrode 1 is provided on a heat insulating layer 12, an ink ejection port 2 is provided so as to face the signal electrode 1, and one of the nozzle main bodies which constitutes a part of an ink flow path 3 is formed. A wall is provided as the common electrode 4, and an insulating layer 5 is provided to cover the signal electrode 1 and the common electrode 4 so that the conductive ink is energized only in a predetermined area. A pressure chamber 6 is formed between the signal electrode 1 and the common electrode 4.

An arrow a indicates a line of electric force passing through the conductive ink between the signal electrode 1 and the common electrode 4, and a volume portion indicated by A indicates a distance between the signal electrode 1 and the common electrode 4. 3A shows a current passage portion of a conductive ink composed of a, an electrode width b, and an electrode length c.

The operation of the ink jet head configured as described above will be described below.

When a potential difference is generated between an arbitrary signal electrode 1 and a common electrode 4 by a voltage applying device (not shown), a current passing portion of a conductive ink having an arbitrary volume resistivity as shown in FIGS. 1 and 2. At A, a line of electric force a is generated between the signal electrode 1 and the common electrode 4, and a current flows along this line of electric force a. Therefore, the conductive ink in the current passing portion A self-heats due to I ² R, and finally boiling starts to generate a bubble (not shown), whereby the pressure of the conductive ink in the pressure chamber 6 is rapidly increased. The conductive ink droplets 19 are ejected from the ink ejection port 2 and are ejected onto the recording paper (not shown) to be attached thereto to form dots. Of course, since the consumed conductive ink is constantly replenished from the ink flow path 3, the conductive ink droplet 19 corresponding to the signal is continuously generated,
Arbitrary continuous dot formation is possible on the recording paper.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. 3 and 4. In addition,
The same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

As shown in the figure, the top plate forming a part of the nozzle forming the ink flow path 7 is composed of the common electrode 8,
The ink ejection port 9 is formed at one end of the nozzle. A pressure chamber 10 is provided between the signal electrode 1 and the common electrode 8.

Further, the volume portion indicated by A indicates a current passage portion of the conductive ink which is constituted by the distance d between the signal electrode 1 and the common electrode 7 and the electrode width e and the electrode length f.

The operation of the ink jet head configured as described above will be described below.

When a potential difference is generated between the arbitrary signal electrode 1 and the common electrode 8 by a voltage applying device (not shown), a current passing portion of conductive ink having an arbitrary volume resistivity as shown in FIGS. 3 and 4. At A, a line of electric force a is generated between the signal electrode 1 and the common electrode 8, and a current flows along this line of electric force a. Therefore, the conductive ink in the current passing portion A self-heats due to I ² R, and finally boiling starts to generate bubbles (not shown), which causes the pressure of the conductive ink in the pressure chamber 10 to rapidly increase. , A conductive ink droplet 19 is ejected from the ink ejection port 9 and is ejected onto a recording paper (not shown),
Adhere to form dots. Of course, since the consumed conductive ink is constantly replenished from the ink flow path 7, conductive ink drops 19 corresponding to the signal are continuously generated, and arbitrary continuous dot formation can be performed on the recording paper. Becomes

[0024]

As is apparent from the above embodiments, according to the present invention, conductive ink, a plurality of counter electrodes corresponding to a plurality of nozzles, and pressure chambers existing between the counter electrodes, An ink flow path for guiding the ink to the pressure chamber,
A voltage applying device for applying an energizing voltage to the arbitrary counter electrode is provided, and a part of the pressure chamber is formed by one wall portion of the nozzle to be one electrode of the counter electrode. It is possible to provide an excellent inkjet head in which the conductive ink having a small volume can be efficiently heated because the opposing area can be made small and the conductive line is only the signal line, and the density can be easily increased. .

[Brief description of drawings]

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

FIG. 2 is a plan sectional view of the inkjet head.

FIG. 3 is a vertical sectional view of an inkjet head according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of the inkjet head.

FIG. 5 is a vertical cross-sectional view of a conventional inkjet head

FIG. 6 is a plan sectional view of the inkjet head.

[Explanation of symbols]

1 signal electrode 2,9 ink outlet 3,7 ink flow path 4,8 common electrode

Continued front page    (72) Inventor Tomoyuki Noguchi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (2)

[Claims] 1. A plurality of nozzles, a counter electrode corresponding to the nozzle, a pressure chamber existing between the counter electrodes, an ink flow path for guiding ink of a conductive hole to the pressure chamber, and the arbitrary counter electrode. And a voltage applying device for applying a conduction voltage to the ink jet head, wherein a part of the pressure chamber is formed by a wall portion of the nozzle, and the ink jet head is used as one electrode of the counter electrode. 2. The ink jet head according to claim 1, wherein a top plate forming a part of the nozzle is a common electrode.