JPH04216939A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To provide an ink jet head generating no stagnation of an air bubble, imparting high printing quality, having high reliability and simplified in its structure. CONSTITUTION:A pressure chamber 2 is arranged to one surface of a head substrate 1. One end of the pressure chamber 2 communicates with ink emitting nozzles 8 through communication paths 10 and the other end thereof communicates with the ink chamber 4 provided to the surface opposite to the surface having the pressure chamber 2 formed thereto of the substrate 1 through a throttled part 3. The ink chamber 4 communicates with the fine orifices 8d opened in the vicinity of the nozzles through the holes 11 and communication paths 12 piercing the head substrate 1. By omitting the throttled part 3, flow path resistance is set low as compared with the flow paths communicating with the ink emitting nozzles 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording head used in an inkjet printer.

0002

[Prior Art] In order to meet the demands for high print quality and low cost for inkjet printers, it is necessary to increase the nozzle density, and a simpler structure is required. As seen in Japanese Unexamined Patent Publication No. 56-172, a plurality of pressure chambers and a U-shaped ink chamber are arranged around them on a common substrate, and ink droplets are ejected from a nozzle opened on the opposite side. Inkjet recording heads have been proposed. However, in such a recording head, air bubbles remain in the ink chamber, particularly at the ends thereof, and once they remain, it is difficult to discharge them.

0003

[Problems to be Solved by the Invention] The present invention has been made in view of these problems, and its purpose is to provide a new method that eliminates the accumulation of air bubbles, achieves high printing quality, high reliability, and has a simple structure. Our purpose is to propose an inkjet recording head.

0004

[Means for Solving the Problems] That is, the present invention provides an inkjet recording head for solving such problems, in which a plurality of pressure chambers are recessed in one surface of a head substrate, and the A communication path to the nozzle that opens on the opposite side of the substrate is provided, and a communication path to the ink chamber is provided from the other end of the pressure chamber, and ink is supplied to a part of the ink chamber. The end of the nozzle communicates with a pore opened near the nozzle.

[0005]

[Embodiment] The embodiment shown in the drawings will be explained below. FIG. 1 is a plan view of an inkjet recording head according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line EE in FIG. In addition, in FIG. 1, the cover plate 5, nozzle plate 6, and drive element 7 shown in FIG. 2 are omitted.

FIG. 3 is a view of the head substrate 1 shown in FIG. 1 from the back side, with the nozzle plate 6 shown in FIG. 2 omitted.

In the figure, pressure chambers 2 are arranged on one surface of a head substrate 1, and one end 2a of each pressure chamber 2 is connected to an ink discharge nozzle 8 through a communication path 10, as shown in FIG.
is connected to. The other end 2b of each pressure chamber 2 communicates with an ink chamber 4 provided on a surface opposite to the surface on which each pressure chamber 2 is formed via a constriction portion 3.

In FIG. 2, 5 is a cover plate that covers the pressure chamber 2, 7 is a drive element for generating pressure, and 6 is a nozzle plate that forms the ink chamber 4 and also has a nozzle 8.

The ink chamber 4 is provided in an annular shape as shown by the broken line in FIG. 1 or the solid line in FIG. 3, and is arranged so as to overlap the pressure chamber 2. Ink is supplied to the ink chamber 4 from an ink cartridge (not shown) through an ink supply pipe 9. The ink chamber 4 is formed with a smooth line without corners so that air bubbles can flow.

FIG. 4 shows a partially enlarged view of FIG. 1, and FIG. 5 shows a sectional view taken along line 4F--F. End portion 4a of ink chamber 4
, 4b communicate with the opposite surface through a hole 11 penetrating the head substrate 1, and further communicate with a small hole 8d opened near the nozzle through one communication path 12. Structurally, the structure is similar to that shown in the cross-sectional view of FIG. 2, but by omitting the throttle section 3, the flow path resistance is set to be smaller than that of each flow path leading to the ink ejection nozzle. The hole diameter of pore 8d is nozzle 8.
is almost the same.

A series of flow paths such as the pressure chamber 2, ink chamber 4, and constriction section 3 are formed on the head substrate 1 by injection molding, etching, etc.
However, the nozzle 8 and the constriction part 3, which have a fine opening and require precision of several microns, can be made by ultraviolet laser processing that irradiates the pressure chamber 2 from a direction perpendicular to the pressure chamber 2, or can be made with particularly high precision using a fine drill. can be made to

That is, the nozzle 8 and the pore 8d can be processed by a laser beam irradiated from the left side in FIGS. 2 and 5 through the communicating paths 10 and 12.

FIG. 6 shows another embodiment of the ink jet recording head according to the present invention, in which the communicating passages 11 and 12 of FIG. 4 are omitted and two small holes 8e are directly formed in the nozzle plate 6.

According to the structure of the above embodiment, the ink chamber 4 communicating with each pressure chamber 2 is set in an annular shape, ink is supplied to approximately the center thereof, and the end of the ink chamber has a small hole opened near the nozzle. It communicates with Therefore, even if air bubbles enter, if the ink is sucked from the nozzle side, the ink from the ink supply pipe 9 will flow and circulate within the ink chamber 4, and the air bubbles will not stay anywhere, including the end of the ink chamber. can be easily discharged through the pressure chamber or the end of the ink chamber.

The flow paths from the ends of the ink chamber to the pores 8d and 8e are designed to have a smaller flow resistance than the flow paths leading to the nozzle 8, so air bubbles can be easily discharged from the ends of the ink chamber. be. By opening a pore communicating with the end of the ink chamber near the nozzle, suction can be performed from the ink discharge nozzle and the pore with the same negative pressure using the same suction device such as a cap.

[0016]

As described above, according to the present invention, it is possible to construct an ink jet recording head having a simple structure and having a reliable ink chamber in which no air bubbles remain.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an inkjet head according to the present invention.

FIG. 2 is a sectional view taken along line EE in FIG. 1;

FIG. 3 is a view seen from the back side of FIG. 1.

FIG. 4 is a partially enlarged view of FIG. 1;

FIG. 5 is a sectional view taken along line FF in FIG. 4;

FIG. 6 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 Head board 2 Pressure chamber 3 Aperture part 4 Ink chamber 6 Nozzle plate 8 Nozzle 8d Pore for air bubble discharge 8e Pore for air bubble discharge 10 Communication path 11 Communication path 12 Communication path

Claims (1)

[Claims] 1. A plurality of pressure chambers are recessed in one surface of a head substrate, and a communication path is provided from an end of each pressure chamber to a nozzle opening on the opposite surface of the substrate, and A communicating path to the ink chamber is provided from the end, and ink is supplied to a part of the ink chamber, and the end of the ink chamber communicates with a pore opened near the nozzle. Inkjet recording head.