JPH03132350A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To achieve stabilization of a discharge characteristic by a method wherein both nozzles are separated from each other at a specified interval via a spacer installed by being projected from at least either of an ink nozzle component or an air nozzle component. CONSTITUTION:A spacer 100 is formed by being projected from an ink nozzle component 3 toward an air nozzle component 2 so as to cut another at a right angle in the arranging direction of ink discharge opening 7 at a position being between adjacent ink discharge openings 7 and between adjacent air discharge openings 8 in an air layer 5. Its tip is stuck fast to an air nozzle component 2, and both nozzle components 2, 3 are separated from each other via the spacer 100. Since each pair of the ink discharge opening 7 and air discharge opening 8 is separated from another pair of the ink discharge opening 7 and air discharge opening 8 which are respectively adjacent thereto by the spacer 100, an air current flowing out from each air discharge opening 8 is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an inkjet recording head that records characters, figures, images, etc. on a recording material by ejecting ink liquid from minute nozzles using airflow. be.

2. Description of the Related Art Recently, inkjet recording heads have come to be widely used in the fields of terminal equipment such as color printers and converters. As an example of this inkjet recording head, a configuration as shown in FIG. 3 is known. Hereinafter, a conventional inkjet recording head will be explained with reference to FIG.

In the figure, a body member 1 made of an insulating material includes an air chamber 4 and an ink chamber 6 therein.

An air nozzle member 2 made of an insulating material is arranged at the opening facing the outside of the air chamber 4, and an air layer 5 is formed between the air nozzle member 2 made of an insulating material, and an insulating material is arranged at the opening facing the outside of the ink chamber e. An ink nozzle member 3 made of The air nozzle member 2 has a plurality of air discharge ports 8 perforated therein, and the ink nozzle member 3 also has a plurality of ink discharge lowers perforated therein opposite to the air discharge ports 8. A common electrode 9 is provided on the outer surface of the air nozzle member 2 at the outer periphery of the air discharge port 8,
Control electrodes 1o are provided on the inner surface of the ink nozzle member 3 in a separated and independent manner on the outer periphery of each ink discharge lower. A signal source 11 is connected to each electrode 9.1o.

Here, a constant flow rate of air is supplied to the air layer 6 from an air supply source (not shown in the figure) via the air supply path 12 and the air chamber 4. This air flows out from the air discharge port 8 while making a sharp bend near the air discharge port 8 and the ink discharge lower.

The ink chamber 6 is constantly filled with ink supplied from an ink supply source (not shown in the figure) via an ink supply path 13 . A constant pressure is applied to the ink in the ink chamber e by the air pressure sent from the air supply source to the ink supply source. As a result, when the inkjet recording apparatus is driven, the air pressure near the ink discharge lower is approximately equal to the ink pressure in the ink discharge ports γ, and the ink meniscus generated in the ink discharge lower is kept stationary.

Here, when a potential difference is provided between the common electrode 9 and the control electrode 10, the meniscus of ink generated in the ink discharge lower part is stretched in the direction of the air discharge port 8 due to the influence of electrostatic force due to this potential difference. When the ink meniscus is stretched beyond a certain length due to the pressure gradient caused by the bending of the air flow described above, it is ejected from the air ejection port 8.

In an inkjet recording head with such a structure,
The uniformity of the dimensional structure and thickness of the air layer 60 is important. That is, FIG. 6 is a graph showing the relationship between the air layer thickness of each of the 24 ejection ports, the amount of ink ejected, and the ejection response.As can be seen from this, the air layer thickness depends on the ink. This has a large effect on the ejection amount and the ejection response of the ink liquid.

This is because the uniformity of shape and thickness within the air layer 6 affects the airflow flowing out from the air outlet 8. Therefore, in order to eliminate this effect, it is necessary to control the variation in the air layer thickness with very high precision. Therefore, countermeasures such as those shown in FIG. 4 have been considered in the past. That is,
Protrusions 14 are provided from the ink nozzle member 3 side between adjacent air discharge ports 8. It was designed to flow out.

Problem to be Solved by the Invention In realizing such a configuration, both nozzle members 2
．． Conventionally, the spacer structure for isolating between the three spaces has been such that, for example, a step is provided in the part where the ink nozzle member is attached and the part where the air nozzle member is attached to the body member. but,
In this case, a body member having a structure corresponding to the thickness of the ink nozzle member is required, which has the disadvantage that the body member becomes large. Spacers manufactured from thin, plate-shaped materials by processing methods such as etching have had the problem of requiring advanced technology to make the shape accurate.

The purpose of this invention is to solve the above problems, and it is possible to easily and accurately control the thickness of the air layer, and to make the air flow independent, thereby stabilizing the discharge characteristics. It is intended to be used in various ways.

Means for Solving the Problems In order to solve the above problems, an inkjet recording head according to the present invention provides a spacer that projects from at least one of an ink nozzle member and an air nozzle member, so that both nozzle members are connected to a predetermined position. I try to keep them apart.

In this configuration, the pair of ink discharge ports and air discharge ports are connected to adjacent ink discharge ports and air discharge ports,
They may be separated by a spacer formed between them.

By providing the working spacer so as to protrude from at least one of the ink nozzle member and the air nozzle member, the body member does not become larger and the manufacturing process can be simplified. In particular, if a spacer is provided in the middle of each outlet, it becomes easy to achieve independent airflow at each outlet.

Embodiment FIG. 1 is an enlarged cross-sectional view of a main part of an inkjet recording head according to an embodiment of the present invention.

In the figure, 2 is an air nozzle member, 3 is an ink nozzle member arranged in parallel with this, 7 is an ink discharge port, and 8 is an air discharge port. They are formed in opposing shapes. 6 is an air layer formed between the air nozzle member 2 and the ink nozzle member 30;
9 is a common electrode provided on the outer periphery of the air discharge port 8 on the outer surface of the air nozzle member 2, and 10 is a control electrode provided separately and independently on the outer periphery of the ink discharge lower on the inner surface of the ink nozzle member 3. This configuration is the same as the conventional example shown in FIG. 3, and therefore the structure of the body member and the like are also the same as in FIG. 3.

In this embodiment, in an ink jet recording head having such a configuration, the ink discharge lowers are arranged in the air layer 6 at positions between the adjacent ink discharge lowers, the 70 holes, and the adjacent air discharge ports 8 and 80. A spacer 100 is formed to protrude from the ink nozzle member 3 toward the air nozzle member 2 so as to be perpendicular to the direction, and the tip of the spacer 100 is in close contact with the air nozzle member. That is, both nozzle members 2.3 are separated by a predetermined distance via these spacers 100.

Next, specific processing and assembly steps for the inkjet recording head according to the embodiment shown in FIG. 1 will be explained.

As the nozzle member, for example, photosensitive glass, photosensitive ceramic, photosensitive resin, etc. can be used, but here, a case where photosensitive resin is used will be described.

First, using a light exposure technique, a portion of the ink nozzle member other than the portion where the spacer 100 will be formed is coated with approximately 300 to 450
Irradiate with nm wavelength Shiba radiation. At this time, the amount of external radiation irradiation is adjusted so that only the depth of the predetermined gap a is exposed. Next, in order to form the protrusion 16 around the ink discharge lower, the spacer 100 and a portion other than the portion that will become the protrusion 16 are exposed to a predetermined depth b. Furthermore, in order to form the ink discharge lower, only the portion that will become the ink discharge lower is exposed to light by the amount of exposure that passes through the ink nozzle member 3. When the ink nozzle member exposed to light as described above is immersed in a developer having a predetermined composition, an ink nozzle member 3 having the shape shown in FIG. 1 is obtained.

The characteristics of the ink nozzle member 3 obtained by this method are as follows:
Since a light exposure technique that allows precise processing is used, the gaps a and b are formed with very high precision. The air nozzle member 2 can also be formed using a similar technique.

Next, the ink nozzle member 3 is adhered onto the body member. Then, the air nozzle member 2 is positioned so that the air ejection opening 8 is aligned with the ink ejection lower formed in the ink nozzle member 3, and the air nozzle member 2 is pressed tightly onto the body member using an adhesive.

At this time, since the spacer 100 is in close contact with the air nozzle member 2 at a plurality of locations, the thickness of the air layer 6 is controlled with high precision. In addition, the six pairs of ink discharge lowers and air discharge ports 8 are adjacent to each other.
Since they are separated by the spacer 100, the airflow flowing out of each air outlet 8 is also stabilized.

FIG. 2 shows the relationship between the air layer of the 24 ejection ports of the inkjet recording head, the amount of ink liquid ejected, and the ejection response according to this embodiment. As can be seen from this, when the uniformity of the thickness of the air layer becomes better, the discharge characteristics are significantly improved.

In the above embodiment, the spacer 100 was formed to protrude from the ink nozzle member 3, but it may also be formed to protrude from the air nozzle member 2 toward the ink nozzle member 3.
Further, both nozzle members 2.3 may be formed to protrude toward each other.

In the above embodiment, spacers are provided between all adjacent discharge ports, but the spacer 100 is provided between both nozzle members 2
．． If it is possible to separate 30 minutes, it is not necessary that
It is not necessary to provide such a position between the discharge ports.

Effects of the Invention According to the present invention, since the gap between the air discharge port and the ink discharge port is controlled by the spacer provided so as to protrude from at least one of the ink nozzle member and the air nozzle member, air of uniform thickness can be produced. The layers are easily obtained and the air flow rate in each is uniform, improving ink ejection characteristics.

When adjacent ejection ports are separated by a spacer, the ink ejection characteristics are further improved. Since the head has such a structure, it can greatly contribute to lowering the price of the inkjet recording head and increasing the yield.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of the inkjet recording head of the present invention, FIG. 2 is a characteristic diagram showing the relationship between the air layer and ejection of the inkjet recording head according to this embodiment, and FIG. 3 is a conventional one. Figure 4 is a cross-sectional view of the main parts of a separate conventional inkjet recording head, and Figure 6 is a characteristic showing the relationship between the air layer and ejection of the conventional inkjet recording head. It is a diagram. 2... Air nozzle member, 3... Ink nozzle member,
7... Ink discharge port, 8... Air discharge port, 1oo・
··Spacer.

Claims (2)

[Claims] (1) An ink nozzle member having a plurality of ink discharge ports and an air nozzle member having a plurality of air discharge ports at a position opposite to the ink discharge ports are connected to at least one of the ink nozzle member and the air nozzle member. Inkjet recording heads are spaced apart by a predetermined distance via spacers provided to protrude. (2) Claim 1, wherein the paired ink discharge ports and air discharge ports are separated by a spacer formed between adjacent ink discharge ports and air discharge ports.
The inkjet recording head described.