JPH0229021B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording head that ejects ink liquid from minute openings and applies the ink to a recorded object.

1. Construction of a conventional example and its problems FIG. 1 shows an embodiment of an inkjet recording head that utilizes airflow and electrostatic force, and is described in detail in Japanese Patent Application Laid-open No. 120452/1983.

A brief explanation will be given below according to FIG.

An air nozzle plate 3 in which air discharge ports 1 are formed and an ink nozzle plate 4 in which ink discharge ports 2 are perforated.
are arranged facing each other to form an air layer 5 with a minute gap. An air flow is sent from the air supply source 11 to the air inlet 9, flows into the air layer 5 through the air chamber 6 provided around the air layer 5, and is focused near the air outlet 1. , the air flows out from the air outlet 1 at a constant flow rate. On the other hand, ink discharge port 2
communicates with an ink reservoir 10 via an ink inlet 8 and is adjacent to an ink chamber 7 filled with ink liquid, and an ink meniscus is formed at the ink discharge port 2 .

The signal source 13 is connected to create a potential difference between the electrode 12 fixed around the air outlet 1 and the ink in the ink chamber 7, and the electrostatic force generated by this potential difference causes As a result, the meniscus of ink generated at the ink ejection port 2 is stretched, accelerated by the air flow flowing out from the air ejection port 1, and the ink liquid is ejected through the air ejection port 1.

FIG. 2 shows an embodiment in which the inkjet recording head of FIG. 1 is made into a multi-nozzle type. In FIG. 2, ink discharge ports 201 to 207 are arranged adjacent to a common ink chamber 70, and air discharge ports 101 to 107 are arranged opposite to them and at a constant interval of an air layer 50. (Second
In the figure, only the air outlet 104 is shown. )
A common electrode 120 is provided on the surfaces of the air discharge ports 101 to 107, and independent control electrodes 141 to 147 are provided on the back surfaces of the ink discharge ports 201 to 207, and a potential difference is provided between them. Since the potentials of the control electrodes 141 to 147 are independently controlled, ink ejection from the ink ejection ports 101 to 107 can be independently controlled. Note that the air flow flows in from the air inflow path 90, passes through the air layer 50, and flows out from the air discharge ports 101 to 107.

In the multi-nozzle head shown in FIG.
147 to the outside of the head, the ink ejection ports 201 to 207 are perforated, and the electrodes 14
The ink nozzle member 16 to which the ink nozzles 1 to 147 are fixed is bent and guided to the side of the head, and the electrode 14
1 to 147 are connected to insertion pins 151 to 157. The reason why the ink nozzle member 16 is bent in this way is that the air flow flowing into the air layer 50 has a uniform flow rate around the air layer 50 and flows out from each of the air discharge ports 101 to 107.
This is because consideration was given to keeping the velocity and flow rate of the airflow constant.

However, in the past, such an ink nozzle member 16 had to be bendable, so there was a difficulty in selecting the material. That is, in the case of easily bendable materials such as nylon and polyimide, since they do not have rigidity themselves, the positional accuracy of the ink ejection ports 201 to 207 decreases, and the uniformity of the thickness of the air layer 50 is impaired. . Glass epoxy with a thickness of about 0.1 mm was able to maintain relative rigidity, but cracks were likely to occur at the bent portions, and there was a risk of disconnection of the electrodes 141 to 147. Furthermore, since bendable materials generally contain many organic substances such as resins, there is also a problem in the corrosion resistance of the materials when oil-based inks are used.

Purpose of the Invention The present invention solves the above-mentioned difficulties and realizes an ink ejection port that is rigid and has good positional accuracy.
The purpose of this invention is to realize a structure of an inkjet recording head in which air flow is uniform and electrodes can be easily pulled out.

Structure of the Invention The present invention forms a hollow part in an insulating member having an ink ejection port, uses at least a part of this hollow part as an air flow path, and connects the remaining part from the vicinity of the ink ejection port onto the bridge. This is an inkjet recording head in which connected electrodes are formed and ink is ejected using air flow and electrostatic force.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 shows an embodiment of the invention. Except for the structure of the ink nozzle member, it is almost the same as in FIG. 2, so the same parts are given the same symbols. Third
In the figure, an ink nozzle member 160 is preferably made of a material that is rigid and can be etched, such as photosensitive glass. The ink nozzle member 160 is provided with a hollow portion 17 at a location that should correspond to the air chamber 60 . A bridging portion 18 is left in order to communicate with the outer peripheral portion and maintain the integral shape. The bridge portion 18 is provided corresponding to each of the ink discharge ports 201 to 207, has electrodes 141 to 147 fixed to its back surface, and is electrically connected to insertion pins 151 to 157. In FIG. 3, the air flow flowing in from the air inflow path 90 flows into the air layer 50 from the air chamber 60 through the hollow part 17, so that the air flow becomes uniform, and from each air outlet 101 to 107. The velocity and flow rate of the outflowing air can be made uniform. Therefore, a multi-nozzle head with uniform characteristics is possible.

For example, when using photosensitive glass, the ink nozzle plate 160 can be easily manufactured by exposing the ink discharge ports 201 to 207 and the hollow portion 17 to light and then etching them.
Nos. 1 to 147 can be completed by depositing metals such as Cr, Ni, and Au.

Further, since photosensitive glass has strong solvent resistance, it also has strong corrosion resistance against ink such as oil-based ink.

FIG. 4 shows another embodiment of the present invention, but only the ink nozzle member is shown and is used with the same configuration as FIG. 3. In FIG. 4, the bridge portions 181 to 187 are connected to the ink discharge ports 201 to 207.
Looking at the arrangement direction of the ink ejection ports 201 to 207
The feature is that the ink ejection ports 201 to 207 do not coincide with each other, and are arranged approximately at an intermediate position between the ink ejection ports 201 to 207.

If the thickness of the bridge portions 181 to 187 is sufficiently thin compared to the arrangement pitch of the ink discharge ports 201 to 208, a sufficiently uniform air flow can be obtained even with the configuration shown in FIG. 208 becomes smaller and the density of the ink ejection ports becomes so high that the thickness of the bridges 181 to 187 cannot be ignored, the bridges 181 to 187 themselves obstruct the air flow, and the air flow is reduced. This may impair the uniformity of the image. The configuration shown in FIG. 4 is useful when the ink ejection ports are densely packed in this way, and the air flow is obstructed by the bridges 181 to 187 on the left and right sides when viewed from the ink ejection ports 201 to 208. Since they are similar, uniformity of airflow can be maintained. Note that the bridge portion 19 is for reinforcement.

Effects of the Invention As described above, the present invention forms a hollow portion that serves as an air flow path in a plate-like member made of an insulating material, and a number of bridge portions corresponding to the number of ink ejection ports, and air ejection ports are formed in this. In the inkjet recording head in which the ink nozzle part and the air nozzle part are formed by opposingly disposed members, a rigid material can be used, so the ink ejection opening is firmly fixed and the characteristics are stable. Further, a uniform airflow can be obtained without difficulty in taking out the electrodes, and a multi-nozzle head with uniform characteristics can be provided. Furthermore, since glass can be used, the inkjet recording head can be constructed of a material with good ink resistance.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram showing a conventional inkjet recording head, FIGS. 2a and b are sectional views showing a conventional multi-nozzle inkjet recording head, and FIG.
Figures a and b are sectional views showing one embodiment of the inkjet recording head according to the invention, and FIG. 4 is a plan view of another embodiment of the inkjet recording head according to the invention. 1,101-107...Air discharge port, 2,20
1-207...Ink ejection port, 141-147...
...Electrode, 5,50...Air layer, 6,60...Air chamber, 17...Hollow part, 18,181-187...
Bridge portion, 16,160... Ink nozzle member, 1
51-157...Insertion pin, 7,70...Ink chamber.

Claims (1)

[Scope of Claims] 1. A hollow part serving as an air flow path and at least a number of bridge parts corresponding to the number of ink discharge ports are formed in an insulating first member in which an ink discharge port is formed, and An electrode film is formed so as to communicate from the vicinity of the ink discharge port on the member to the bridge part, and the first member and the second member in which the air discharge port is formed are made to face each other, and the air flow and static An inkjet recording head characterized by ejecting ink liquid using electric power. 2. The inkjet recording head according to claim 1, wherein the first member is photosensitive glass.