JPH0867008A - Ink-jet recording head - Google Patents

Abstract

PURPOSE: To provide an ink-jet recording head which discharges ink droplets stably and makes high speed drive and high printing quality possible. CONSTITUTION: A head has an orifice plate 1 equipped with an ink discharge opening 1A for discharging ink Wo as ink droplets (w), an orifice space S for holding the ink Wo discharged from the opening 1A, a channel forming plate 2 for introducing the ink Wo into the orifice space S, and a head substrate 3 for supporting integrally the channel forming plate 2 and the orifice plate 1. A heat generating resistance 4 is installed on the head substrate 3 corresponding to the ink discharge opening 1A; a water repellent treatment part H is installed on the periphery of the opening 1A of the orifice plate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head, and more particularly to an ink jet recording head which ejects ink to form ink droplets for recording.

[0002]

2. Description of the Related Art In an ink jet recording head, stable ejection of ink droplets from an ink ejection port is regarded as the most important factor in achieving high speed driving and high printing quality.

Unstable ejection of ink droplets is generally caused by ink overflow at the ejection port. Then, when the ink overflows around the ejection port of the orifice plate when the recording head is used, the trailing portion of the ejected ink droplet is pulled by the ink overflow, which causes the ejected ink droplet to have a poor directionality. As a result, the print quality is significantly reduced. Further, when the ink overflow becomes large to cover the ejection port, ejected ink droplets are ejected inside the ejection port, so that the ejection state becomes very unstable.

On the other hand, in order to solve these problems,
Conventionally, a method of coating the periphery of the orifice plate discharge port with a water repellent treatment agent is known.

The water repellent treatment method for this orifice plate is the following method, that is, the produced recording head is dipped in a water repellent treatment agent. ． A method of spray applying a water repellent treatment agent ,. A method of sputtering a water repellent agent ,. Japanese Unexamined Patent Publication (Kokai) No. 63-122557 (Method for exposing end face of discharge port to treatment agent while jetting gas such as nitrogen or air from discharge port of orifice plate during water repellent treatment), Is that.

[0006]

In most of the water repellent treatment methods in the above-mentioned conventional example, as shown in FIG. 3, the entire surface of the orifice plate 51 is subjected to the water repellent treatment H. Therefore, when the recording head operates and the heat generating resistor 52 is driven, the ink overflow state in this driving state is caused by the effect of the water repellent treatment agent H on the ink overflowing from the ejection port 51A to the periphery of the ejection port. It becomes spherical and flows out around the discharge port 51A. When the ink overflow amount increases, the overflowed ink becomes one large sphere and stays around the ejection port. For this reason, as a result, the ejected ink droplet is pulled by the ink reservoir K overflowing in a spherical shape, which causes a disadvantage that the ejection is unstable even in such a case.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording head which solves the disadvantages of the prior art, particularly ejects ink droplets in a stable state, and thereby enables high speed driving and high printing quality. Is the purpose.

[0008]

According to the present invention, an orifice plate having an ink ejection port for ejecting ink as an ink droplet, an orifice space for holding ink ejected from the ink ejection port, and an ink in the orifice space are provided. And a head substrate integrally supporting the flow path forming plate and the orifice plate. Further, a heating resistor is provided on the head substrate corresponding to the ink ejection port. Then, a water repellent treatment portion is provided around the ink discharge port of the orifice plate. This aims to achieve the above-mentioned object.

[0009]

[Operation] When ink overflows around the ink ejection opening 1A of the orifice plate 1, the overflowing ink W is repelled by the effect of the water repellent treatment portion H around the ejection opening, and the water repellent untreated portion J is repelled. Accumulate in. Even if the water-repellent treated portion H collects in a spherical shape, the ink collection does not affect the ejected ink droplet w because it is formed in a very small area around the ejection opening 1A. Therefore, the ink droplet w can be ejected in a stable state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the embodiment shown in FIG. 1, an orifice plate 1 having an ink ejection port 1A for ejecting ink Wo as an ink droplet w, and an orifice space for holding the ink Wo to be ejected from the ink ejection port 1A. S, a flow path forming plate 2 that introduces the ink Wo into the orifice space S, and a head substrate (silicon substrate) 3 that integrally supports the flow path forming plate 2 and the orifice plate 1.

A heating resistor 4 is provided on the head substrate 3 in correspondence with the ink ejection port 1A. A water repellent treatment portion H is provided in an annular shape around the ink ejection port 1A of the orifice plate 1. The water repellent treatment portion H is formed in a donut shape having a predetermined width. The water-repellent treatment section H is specifically configured by forming the water-repellent plate 10 in an annular shape and equipping it around the ink ejection port 1A.

An example of a method of manufacturing the water repellent plate 10 will be described here.

First, as shown in FIG. 2A, a recess 10a is formed in the orifice plate 1 at a position corresponding to the discharge port 1A by micromolding. Next, on the entire surface of the orifice plate 1 on the ink ejection side, as shown in FIG.
As shown in (b), the water repellent treated portion H is formed. As a forming method, a method such as spray coating, spin coating, or sputtering is used.

Next, as shown in FIG. 2C, the surface of the orifice plate 1 on which the water repellent treatment portion H is formed is polished to such an extent that the water repellent treatment portion H remains in the recess 10a. Finally, the discharge port 1A is precisely formed by laser processing as shown in FIG. This makes the water repellent plate 10
The manufacturing process of is completed.

As described above, in the present embodiment, the ink jet recording head is designed so that only the peripheral portion of the ink ejection port 1A of the orifice plate 1 is subjected to the water repellent treatment. For this reason, when the ink overflows, the overflowed ink W is repelled by the effect of the water repellent treatment portion H around the ejection port and collects in the water repellent untreated portion J (see FIG. 1).

Even if the water-repellent treated portion H is accumulated in a spherical shape, the ink reservoir is formed in a very small area around the ejection opening 1A and therefore does not affect the ejected ink droplet w. Therefore, the ink droplet w can be ejected in a stable state, which is effective for high speed driving and high print quality.

[0018]

Since the present invention is constructed and functions as described above, according to the present invention, the overflow occurs due to the synergistic effect of the water repellent treated portion around the ink ejection port of the orifice plate and the other water repellent untreated portion. It is possible to effectively eliminate the inconvenience that the overflowed ink stays around the ink discharge port because the accumulated ink remains in the water-repellent untreated portion, and therefore, it is possible to discharge the ink droplet in a stable state, Therefore,
It is possible to provide an unprecedented excellent inkjet recording head in which higher speed driving and higher printing quality can be achieved than ever before.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention and an operation example thereof.

FIG. 2 is an explanatory view showing a procedure of a method of manufacturing the water repellent treatment portion disclosed in FIG. 1, FIG. 2 (a) showing an orifice plate having a concave shape around a discharge port, and FIG. 2) shows a diagram in which the water repellent treatment portion H is formed on the entire outer surface of the orifice plate including the recessed portion, and FIG. FIG. 2 (d) is a view obtained by precisely forming discharge ports by laser processing, and FIG. 2 (d) is a view removed by polishing.

FIG. 3 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1 Orifice plate 1A Ink ejection port 2 Flow path forming plate 3 Head substrate 4 Heat generating resistor 10 Water repellent plate H Water repellent treated portion J Water repellent untreated portion W, Wo ink w Ink droplet S Orifice space

Claims (3)

[Claims] 1. An orifice plate having an ink ejection port for ejecting ink as an ink droplet, an orifice space for holding ink ejected from the ink ejection port, and a flow path forming plate for introducing ink into the orifice space. An ink jet recording head having a head substrate integrally supporting the flow path forming plate and the orifice plate, and equipped with a heating resistor on the head substrate corresponding to the ink ejection ports, An ink jet recording head, characterized in that a water repellent treatment portion is provided in a peripheral portion of the ink discharge port of the orifice plate. 2. The ink jet recording head according to claim 1, wherein the water repellent treatment portion is formed in a donut shape having a predetermined width. 3. The ink jet recording head according to claim 1, wherein the water repellent treatment unit is formed by forming a water repellent plate in an annular shape around the ink ejection port.