JPS60129263A - Ink jet head - Google Patents

Abstract

PURPOSE:To obtain an ink jet head capable of jetting ink to a given position with good accuracy and also of easily removing air bubbles coming into an ink introducing path by providing a nozzle through which ink is to be jetted at a specific position. CONSTITUTION:A nozzle 13A is provided vertically to an ink introducing path 12A on the tip of the path 12A leading to a pressure chamber 11A, and the opening end 14 is closed with an elastic material 15. The nozzle port can be easily processed by a discharge processing, and air bubbles coming into the path 12A can be released and removed from the tip portion 101 by removing a plate spring 17, a metal part 16, and then the elastic material 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an inkjet head, and more particularly to a structure of a highly reliable inkjet head capable of recording with high print quality.

fb) Background of the technology By applying a voltage to a piezoelectric element installed above a pressure chamber containing print recording ink in accordance with the printed information, the piezoelectric element is distorted, and the pressure caused by this distortion is An inkjet recording method is well known in which printing ink stored in the pressure chamber is ejected onto recording paper from a nozzle that communicates with the pressure chamber and is provided at one end of the pressure chamber. . This inkjet recording method is a non-impact recording method that generates little noise during printing and has a fast printing speed, so it has recently become widely used for recording information output from electronic computers. There is.

(C) Prior art and problems Figure 1 is a plan view of a conventional inkjet head, and Figure 2 is a plan view of a conventional inkjet head.
The figure is a sectional view of FIG. 1 taken along line I-n.

As shown in the figure, the conventional inkjet head contains ink for printing and recording and includes piezoelectric elements 1A, IB, .
Pressure chambers 2A, 2B, . . . transmit pressure from .
...and nozzles 3Δ, 3B, which communicate with one end of the pressure chambers 2A, 2B, old, and eject ink onto the recording wL (not shown -U) at the end. and pressure chamber 2
A.

The ink outlet passages 4Δ, 4B, which communicate with the nozzles 3A, 3B, and so on, and this pressure chamber 2.
It consists of an ink storage chamber 5 that stores ink for supplying ink to A, 2B, and old, and an ink supply path 6 that supplies ink to this ink storage chamber 5 from an ink tank (not shown). . In order to form such an inkjet head, the pressure chamber 2A described above is formed by electrical discharge machining on a thin plate such as stainless steel to a predetermined size.
, 2B..., nozzle 3A, 3B...
, ink outlet path 4^, 4B..., ink storage chamber 5
Prepare a thin stainless steel plate that has been punched out and processed in this way, and two thin stainless steel plates that have only the tips of the nozzles 3A, 3B, etc. processed into a semi-cylindrical shape. After connecting the thin stainless steel plates by welding, piezoelectric elements 1A, 1B...
・ were fixed on each pressure chamber 2^, 2B, etc. using adhesive or the like, and the ink supply path 6 was further attached using adhesive or the like to form an inkjet head as shown in the figure. .

However, in order to form an inkjet printer head with such a conventional structure, the pressure chambers 2^, 2B, etc., nozzles 3A, 3B, etc., were punched out by electrical discharge machining. One thin stainless steel plate is butted and welded to two thin stainless steel plates on which the tips of the nozzles 3A, 3B, etc. are formed into semi-cylindrical shapes on the top and bottom of this single thin plate. After connecting, the tips of the nozzles 3A, 3B... are polished to a mirror surface in order to eject ink accurately from the nozzle holes at the tips of the nozzles 3A, 3B... to predetermined positions. During this polishing process, the abrasive gets into the fine holes at the tips of the nozzles 3A, 3B...
There are 911 cases in which the tip of the nozzle is clogged or the nozzle hole is not made into a perfect circle during this polishing process.

In this way, if the nozzle holes at the tips of the nozzles 3A, 3B, etc. are not machined into perfect circles, the ink will not be able to be jetted to the desired position on the recording paper, resulting in high reliability. A problem has arisen in that it is not possible to obtain a high degree of ink dient heso F.

In addition, in the structure of a conventional inkjet head, after ink is ejected onto the recording paper from the nozzle holes at the tips of nozzles 3Δ, 3B, etc., the reaction of the energy ejected by the ink causes the air on the surface where the nozzles are exposed. Air bubbles inside are sucked, and these air bubbles enter the ink lead-out paths 4A, 4B... from the nozzles 3A, 3B, etc., preventing accurate printing and recording. ...
...It was difficult to remove the trapped air bubbles.

(d) Purpose of the Invention The present invention eliminates the above-mentioned problems, and is capable of easily removing air bubbles that have entered the ink outlet path from the nozzle, and in which the nozzle hole at the tip of the nozzle is machined in a perfectly circular state. The object of the present invention is to provide a novel inkjet head that can be formed by ejecting ink in a predetermined direction with high precision.

(e) Structure of the Invention In order to achieve the above object, the inkjet head of the present invention includes an ink ejecting nozzle that is adjacent to the tip opening of an ink outlet communicating with a pressure chamber and extends vertically from the ink outlet. In addition, the tip opening of the ink outlet path is sealed with a removable closing means.

(fl Embodiment of the Invention An embodiment of the invention will be described in detail below with reference to the drawings.

FIG. 3 is a plan view showing the structure of the first embodiment of the inkjet head of the present invention, FIG. 4 is a cross-sectional view of FIG. 3 taken along line 1-1f, and FIG. 5 is the inkjet head of the present invention. A plan view showing the structure of the second embodiment of the head, and FIG. 6 is a cross-sectional view taken along line I-II in FIG. 5. Third
4 and 4, the inkjet head of the present invention differs from the conventional inkjet head in that the inkjet head of the present invention is different from the conventional inkjet head in that the tip of the ink outlet path 12^ connected to the pressure chamber 11A is provided with a direction perpendicular to the ink outlet path 12A. The nozzle 13A with high accuracy and high roundness is provided in advance in the ink outlet, and the tip of the ink outlet path 12A is open. An elastic member 15 such as elastic rubber, which serves as a closing means, is pressed against the open end 14 by an elastic leaf spring 17 via a flat metal member 16. The end 14 is sealed. Further, the nozzle hole can be easily formed by electric discharge machining without going through a polishing process.

According to the inkjet head of the present invention, the tip of the nozzle 13Δ is not connected by welding as in the past, so there is no need to finish the tip by polishing, and an abrasive is not added to the nozzle. It is also possible to eliminate phenomena that may occur. In addition, the shape of the nozzle hole can be easily formed into a right circle, so that the print recording ink can be accurately ejected from the nozzle 138 to a predetermined ejection position on the recording paper, resulting in highly reliable print recording. It becomes possible. Further, the tip end portion 101 of the ink outlet path 12A of the present invention, which is further distal to the ink outlet path 12A than the nozzle 138, is configured to remove air bubbles that have entered the ink outlet path 12A. When air bubbles enter A, remove the plate spring 17 and remove the metal member 16, and then remove g!ii 91st part 215,
Furthermore, an ink supply path 6 connected to an ink tank (not shown)
The ink is introduced into the pressure chamber 11/l, and then the piezoelectric element 188 is operated to guide the ink to the ink outlet path 128, and the air bubbles in the ink outlet path 128 are removed from the open end 14 of the ink outlet path 12A. At the same time, the air bubbles introduced into the ink are released to the outside through the ink.

In a conventional inkjet head, air bubbles introduced into the ink outlet path are released from the tip of the nozzle.
In such a conventional structure, the diameter of the hole at the tip of the nozzle is small, so air bubbles introduced into the ink outlet path cannot be easily removed. Since the air bubbles are discharged through the ink outlet path, the air bubbles that have entered the ink outlet path can be easily removed.

Further, a plan view of a second embodiment of the inkjet head of the present invention is shown in FIG. 5, and a sectional view taken along line I--II in FIG. 5 is shown in FIG. The difference between the embodiment of Section 2 and the first embodiment described above is the ink outlet path 218, as shown in FIGS. 5 and 6.

Elastic members 22A, 22B, . . . made of rubber or the like are separately attached to the open ends of the distal ends of the metal members 238.

Screws 24A, 24B... through 23B...
・This is a point that is pressed using etc. With this structure, if air bubbles enter the ink outlet 1/821 A connected to the nozzle 25^, the screw 24
8, the metal member 23Δ, and the elastic member 22, and operate only the upper piezoelectric element 27Δ to the pressure chamber 26 connected to the ink outlet path 21A, thereby removing the air bubbles in the ink outlet path 21A. It can also be removed externally. In this way, when air bubbles enter the ink outlet path 218 from inside the nozzle 258, the ink used to discharge the air bubbles to the outside flows only through the ink outlet path 21, so that the air bubbles can be removed. The amount of ink discharged to the outside during this period is smaller than that in the first embodiment.

(Effects of the Invention As described above, according to the inkjet head of the present invention, the nozzle hole for ejecting ink can be machined into a perfect circle in advance, so the ink ejection direction can be adjusted to a predetermined position.
The ink is sprayed more efficiently, making it possible to print and record with high quality and reliability. Furthermore, since an opening is provided at one end of the ink outlet path, air bubbles that have entered the ink outlet path from the inside of the nozzle can be easily removed.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional inkjet head, FIG. 2 is a cross-sectional view of FIG. 1 taken along line I-n, and FIG. 3 is a first embodiment of an inkjet head according to the present invention. FIG. 4 is a cross-sectional view of FIG. 3 taken along line I-n; FIG. Figure 6 is the same as Figure 5.
It is a sectional view cut along the -11 line. In the figure, LA, IB, 18A, 278 are piezoelectric elements, 2
Eight, 2B. 118, 268 are pressure chambers, 38, 3B, 138, 25
8 is a nozzle, 48. 4B, 128, 2LA, 21B, 101 is an ink outlet path, 5 is an ink storage chamber, 6 is an ink supply path, 14 is an open end, 15, 22A, 22B is an elastic member, 16, 2
38, 23B is a metal member, 17 is a plate spring, 24Δ, 24
B indicates a screw. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] An ink ejection nozzle extending vertically from the ink outlet path is provided adjacent to the tip opening of the ink outlet path communicating with the pressure chamber, and the tip opening of the ink outlet path is sealed with a removable closing means. An inkjet head characterized by: