JPS61162360A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To obtain a satisfactory recording quality by providing independent electrodes that are consisting of an electrode plate made of metal plate which is electroplated and joined with an ink nozzle plate, and a portion of the electrode plate which is joined as above is cut to make respectively independent electrodes. CONSTITUTION:Over the whole surface of an electrode plate 20 which is shaped as desired an electroplating is performed in thickness of several mum with an electrochemically stable metal such as rhodium, platinum or gold. Since the independent electrodes 19 (19-1-4) that are totally electroplated as stated above are joined, and therefore, there are few pinholes, dissolving of the independent electrodes caused by electrode reaction of nickel which composes the material of the electrode plate 20 or deposition of reaction substance can be prevented. Further, inasmuch as the independent electrodes are joined to the nozzle plate 14 and thus shaped, no new bridging with the plate 14 is not required, and in addition, the existing bridge portion and its vicinity compose a portion of an air chamber 9, the air flow from the air chamber 9 to an air layer can be made streamlined.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention ejects minute ink droplets in response to an electrical signal.
An image created by ink droplets on recording paper? The present invention relates to an inkjet recording head for recording.

2. Description of the Related Art Recently, inkjet recording heads have come into widespread use in the fields of color printers, computer terminal equipment, and the like. The structure of this inkjet gutter recording head is known, for example, as described in Japanese Unexamined Patent Publication No. 58-220768. Hereinafter, a conventional inkjet recording apparatus and a gutter will be described with reference to FIGS. 3, 4, and 5.

In FIG. 3, 13 is a body member. An insulating air nozzle plate 2 is provided with air discharge ports 1, an insulating ink nozzle plate 14 is arranged parallel to the air nozzle plate 2, and the ink nozzle plate 14 is provided with air discharge ports 1. An ink discharge port 4 is bored opposite the outlet 1. Air flow flows into the air supply path 8 from the air supply source 3, is uniformized in the air chamber 9 having an annular structure, and flows in from around the air layer created by the air nozzle plate 2 and the ink nozzle plate 14. The air flows out from the air outlet 1. Since this air flow changes rapidly near the air outlet 1,
A rapid change in pressure gradient occurs in the space from the ink discharge port 4 to the air discharge port 1. On the other hand, the ink chamber 10 adjacent to the ink discharge port 4 is connected to an ink reservoir 11 via an ink supply path e, and the ink in the ink reservoir 11 is controlled by the air pressure from the air supply source 3 through a pressure adjustment mechanism. A constant pressure regulated by 16 is applied. This is because when the inkjet recording device is not driven, the air pressure near the ink ejection port 4 and the ink pressure in the ink ejection port 4 or the ink chamber 10 are approximately equal, and the meniscus of ink in the ink ejection port 4 is kept stationary. This is to make adjustments so that the

The signal source 6 is connected to an electrode 12 provided around the air outlet 1 and an electrode 16 provided around the ink chamber 10fC of the ink outlet 4, and a potential difference between the electrode 12 and the electrode 16 is established. is caused.

The meniscus of ink generated at the ink ejection port 4 is stretched in the direction of the air ejection port 1 due to the electrostatic force caused by this potential difference. Roughly speaking, since there is a sudden change in the pressure gradient in the space from the ink discharge port 4 to the air discharge port 1, if the ink meniscus generated at the ink discharge port 4 is stretched beyond a certain length, the pressure gradient will change. It is accelerated by the change and flies from the air outlet 1.

Next, a conventional multi-nozzle ink chef recording head having a plurality of sets of air discharge ports 1 and ink discharge ports 4 of the same type as described above will be described with reference to FIG. 4(b). In FIG. 4, air discharge ports 1-1 to 1-4 are perforated at equal intervals in the insulating air nozzle plate 2, and at least the periphery of the air discharge ports 1-1 to 1-4 is perforated. A common electrode 12 is provided on one surface including τ. An insulating ink nozzle plate 14 is installed parallel to the air nozzle plate 2 and on the opposite side from the electrode 12.
Ink ejection ports 4-1 to 4-4 are bored opposite to -1 to 1-4. The insulating ink nozzle plate 14 and the body member 13 form a common ink chamber 1o, which communicates with the ink discharge ports 4-1 to 4-4 and communicates with the ink reservoir via the ink supply path 6. ing. In addition, independent and separated τ electrodes 16-1 to 16-4 are provided around the ink discharge ports 4-1 to 4-4 facing the ink chamber 10, respectively. An air flow flows into the air chamber 9 formed by the air nozzle plate 2 and the body member 13 through the air supply path 8f.
This air flow flows through an air layer 7 formed by the air nozzle plate 2 and the insulating ink nozzle plate 14, and flows through the air layer 7 formed by the air nozzle plate 2 and the insulating ink nozzle plate 14,
From 1 to 1-4, a sharp bend occurs and τ flows out.

The thickness δ of the air layer 7 is determined by the spacer plate 17. On the other hand, a constant pressure is applied to the ink in the ink chamber 10, and the pressure is adjusted so that the ink meniscus is stably maintained at each of the ink ejection ports 4-1 to 4-4 when the inkjet recording device is not driven. ing.

The electrodes 16-1 to 16-4 are connected to signal sources 6-1 to 6-, respectively.
4, and a potential difference can be independently generated between the electrode 12 and the electrode 12 commonly connected to the signal sources 6-1 to 6-1. When a potential difference occurs between the electrodes 16-1 to 16-4 and the electrode 12, the resulting electrostatic force and the change in pressure gradient caused by the air flow cause the ink ejection port 4-
Ink liquid is discharged from 1 to 4-4, and air discharge ports 1-1 to
Fly through 1-4.

Next, referring to FIG. 6, the electrode 16 shown in FIG. 4 will be explained in detail. In FIG. 6, a common electrode 12 is installed on one side of the air nozzle plate 2. And air discharge ports 1-1 to 1-4 are perforated. 17 is a spacer plate for determining the thickness of the air layer. Ink nozzle plate 1
4, ink discharge ports 4-1 to 4-4 are air discharge ports 1-1 to 4-4.
It is perforated so as to face 1-4. Around the ink discharge ports 4-1 to 4-n on one side of the ink nozzle plate 14,
Electrodes 16-1 to 16-4 are provided independently and separately. Ink nozzle plate 14 is used to provide these electrodes.
Bridges 18-1 to 18-4 are provided, and the space around them forms part of the air chamber. Electrode 15
The voltage difference when recording between -1 and 16-4 is several tens
0V, an electrode reaction occurs using the oil-based ink as a medium, causing electrode dissolution and reaction product precipitation.As a countermeasure, electrochemically stable materials such as gold, platinum, and rhodium are applied to the electrode surface. It uses metal. (Special application 1986-116)
(Refer to No. 971) As a conventional method for forming the electrode 16, the following method is used. On one side of the ink nozzle plate 14,
The base layer of chromium is patterned by evaporating chromium and the deposited chromium is deposited using a photo-etching technique or by using an evaporation mask in advance, and then an intermediate layer of nickel and a surface layer of rhodium are formed by plating. , the electrode 15 is formed. Another method is to form the base layer, intermediate layer, and surface layer by vapor deposition to form the electrode 15. As described above, the electrode 15 is formed directly on the surface of the ink nozzle plate 14.

Problems to be Solved by the Invention However, with the above configuration, when forming the surface layer of rhodium on the electrode 16 by plating, a sophisticated technique is required. The formation of oxides makes subsequent nickel and rhodium plating very difficult. In addition, the electrode 16 can be formed only by vapor deposition.
When forming the ink nozzle plate 14, rhodium is expensive and cannot be applied thickly due to cost considerations.Furthermore, if the base layer and intermediate layer between the ink nozzle plate 14 and the rhodium are plated, the ink nozzle plate 14 A problem has frequently arisen in which the electrode 15 is leached or deposited due to electrode reaction from the end face of the pattern between the substrate and rhodium, or in the case of vapor deposition from the pinhole portion of the rhodium at the crotch of the pattern.

Furthermore, although a bridge 18 is rarely required to form the electrode 16, the bridge 18 obstructs the air flow and prevents the air flow from being sent smoothly into the air layer A, resulting in poor recording characteristics. The problem was that I couldn't get it.

The present invention solves the above-mentioned problems of the prior art, and aims to form an electrode that is less likely to cause electrode reactions, is easy to form, is inexpensive, and allows smooth air flow. The purpose is to

Means for Solving the Problems The present invention involves processing an electrode plate to form it into a predetermined shape, plating the formed electrode plate with metal, and bonding it to an ink nozzle plate. The above object can be achieved by cutting off a portion of the electrode plate to form independent electrodes.

Function The present invention has the above-mentioned structure, so that the entire surface of the electrode plate can be plated to a uniform thickness, thereby suppressing melting of the electrode plate and precipitation of reactants due to electrode reaction. Also,
Since the electrode plate is joined to the ink nozzle plate, there is no need to provide a bridge on the ink nozzle plate, so that the airflow can flow smoothly. Furthermore, by processing the shape of the electrode plate three-dimensionally, there is no need to provide the electrode plate at a position between the air chamber and the air layer, so that the airflow can flow smoothly.

EXAMPLE A first example of the present invention will be described below with reference to the drawings.

FIGS. 2(b) and 2(b) are perspective views of an ink nozzle plate and electrodes in the first embodiment of the present invention. The other parts are the same as those shown in FIGS. 3 to 5, and therefore illustration thereof is omitted. In FIG. 2, the material of the electrode plate 2o is a nickel plate. By processing the nickel plate using photoetching technology, it is formed into a predetermined shape as shown in FIG. 2(b).

The predetermined shape is the through hole 22-1 facing the ink discharge ports 4-1 to 4-4 bored in the ink nozzle plate 14.
22-4 are arranged, each has an annular portion 23, and an arm portion 24 serving as a lead line extends outward from the annular portion 23, and the arm portion 24 is connected to one annular outer portion. It has a shape that is connected to the frame portion 26. In other words, the predetermined shape means that the independent electrodes 19-1 to 19-4 consisting of the annular portion 23 and the arm portions 24 are connected to the outer frame portion 26.
It has a shape that is connected to ℃. The entire surface of the electrode plate 2o formed into a predetermined shape is coated with electrochemically stable gold such as adium, platinum, or gold! Plate @ to a thickness of several μm.

At this time, since the thickness of the electrode plate 2o is as thick as 50 to 100 μm, the surface activation treatment before plating can be carried out sufficiently, so that a film with high adhesion strength can be obtained. Painted electrode plate 2o
is bonded to the ink nozzle plate 14 with an adhesive. A part of the joined electrode plate 20 is cut at the cut surface 21, and the outer frame part 26, which is the part that is no longer needed for the turntable, is removed, and independent electrodes 19-1 to 19-4 are formed. is formed.

In the above configuration, since the electrode plate 20 that has been formed into a predetermined shape is an integral structure, a part of the electrode plate 20 is held and the entire surface is plated with rhodium, platinum, gold, etc. to a uniform thickness. This is easy to do, and since the entire surface is wired and bonded to form an independent electrode 19,
rhodium. Since there are few pinhole parts of platinum, gold, etc., it is possible to prevent the independent electrodes 19 from melting or to precipitate reactants due to the electrode reaction of nickel, which is the material of the electrode/electrode plate 20.

Furthermore, since the independent electrodes 19 are formed by being joined to the ink nozzle plate 14, there is no need to provide a bridge on the ink nozzle plate 14, and the bridge portion and its surroundings form part of the air chamber 9. Therefore, the air flow from the air chamber 9 to the air layer can be made completely smooth.

Next, a second embodiment of the present invention will be described.

FIGS. 1(a) and 1(b) are a plan view and a sectional view of an electrode and an inkjet recording head incorporating the electrode in a second embodiment of the present invention. In FIG. 1(a), the difference from the configuration in FIG. 2 is that there is a bent portion 2 on the electrode plate 2o.
6 is provided, and the electrode plate 20 is bent to form a predetermined shape into a three-dimensional shape. The electrode plate 20 is formed into the same shape as shown in FIG. 2(b) by photoetching, and then bent at the bent portion 26 to form a predetermined three-dimensional shape such that the through hole 22 forms the upper side of a trapezoid. After that, it is plated with rhodium etc. Then, the plated electrode plate 20
is joined to the ink nozzle plate 14 as shown in FIG. 1(b).

Note that the electrode plate 20 is arranged along the inner wall of the ink chamber 10 and is fixed by the body member 2, so the electrode plate 20 can be placed adjacent to the ink nozzle plate 14 without being joined to it. good.

In this specification, this state is also expressed as bonding.

The joined electrode plates 2o are cut at the cut portions 21, and the unnecessary parts around them are removed to form independent electrodes 19.
-1 to 19-6 are formed.

In the above configuration, since the independent electrodes 19-1 to 19-6 are not provided at positions between the air chamber 9 and the air layer 7, the air chamber 9
However, the air flow to the air layer 7 can be made smooth. When the airflow becomes smooth, the direction of the airflow flowing out from the plurality of air discharge ports 1 becomes straight, so that the ink droplets discharged from the ink discharge ports 4 are caused to flow through the air discharge ports 1 due to the force of the air flow. Since it flies straight without hitting the inner wall, good recording characteristics can be obtained.

Furthermore, since the entire surface of the independent electrode 19 is plated with a metal such as rhodium to a uniform thickness, the independent electrode 19 is free from melting and reactants due to the electrode reaction, similar to the structure shown in FIG. The precipitation of can be prevented.

In the above description, the material of the electrode plate 20 is a nickel plate, but the material of the electrode plate 2o may be any material that is easy to plate and has approximately the same coefficient of linear expansion as the metal to be plated.

Further, the metals to be plated include rhodium, platinum, and gold, but other metals may be used as long as they are electrochemically stable.

Effects of the Invention As described above, the present invention involves processing an electrode plate to form a predetermined shape, plating the formed electrode plate with a metal plate, joining it to an ink nozzle plate, and forming the joined electrode. By cutting a part of the plate to make each independent electrode,
Electrode reactions are less likely to occur, and since the electrode plate is plated as an integrated structure, it is easy to form and inexpensive.Furthermore, the smooth airflow allows for good recording characteristics. It's thick.

[Brief Description of the Drawings] Figure 1 e), (t)) H- A plan view of the electrode plate and a sectional view of the inkjet recording head in an embodiment of the inkjet recording head according to the present invention, Figure 2 (2L)
, (b) is a perspective view of an ink nozzle plate and an electrode plate in another embodiment of the present invention, FIG. 3 is a sectional view of a conventional inkjet recording device, and FIGS. 4(a) and (b) are a conventional inkjet recording device. A plan view and a sectional view of the recording nozzle, and FIG. 5 is a perspective view of the vicinity of electrodes of a conventional inkjet recording head. 1...Air discharge port, 2...Air nozzle plate, 4
...Ink discharge port, 7... Air layer, 9
...Air chamber, 1o...Ink chamber, 14
...Ink nozzle plate, 19 ...Independent electrode, 20 ... Electrode plate, 21 ... Cutting portion, 22 ... Through hole, 24...Arm part,
26...Bending part. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 5

Claims (2)

[Claims] (1) An air nozzle plate having an air discharge port and an ink nozzle plate having an ink discharge port are disposed facing each other, and are processed into a shape having at least one arm portion having a through hole at the tip,
An electrode plate plated with an electrochemically stable metal is joined to or in contact with the ink nozzle plate so that the through hole corresponds to the ink ejection port, and the electrode plate is removed leaving arm portions of the electrode plate. Inkjet recording head. (2) The inkjet recording head according to claim 1, wherein the arm portion of the electrode plate is bent at a tip portion having a through hole, and the portion including the through hole is joined or contacted with the ink nozzle plate.