JPH03281253A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To approximately equalize air velocity at a plurality of air discharge openings and contrive a way to make uniform recording characteristics between each of the air discharge openings by making the volume of a part separated from an air supply opening side part larger than that of the air supply opening side part in an air chamber. CONSTITUTION:Air is supplied from an air supply source 18 through an air supply pipe 15 and an air supply opening 14 into an air supply opening side part 7a of an air chamber 7. The air thus supplied runs being separated into air flows 7a and 7b along a series of air discharge openings 10-1 - 10-n and into a separation side part 7b and the air flows into an air passageway 6 from both the sides and runs out through each of the air discharge openings 10-1 - 10-n. Since the volume of the separation side part 7b is larger than that of the air supply opening side part 7a in the air chamber 7, there is little pressure loss involved in the lowering of air supply force to the air discharge openings 10 taking place as the air separation from the air supply opening 14 proceeds. Since the pressure loss between each of the air discharge openings 10-1 - 10-n becomes nearly constant, the air velocity at each of the air discharge openings can be made nearly constant and the volume of the air chamber can also be made smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to inkjet recording, which records characters, figures, etc. on a recording material by ejecting ink in response to an electrical signal using an air flow. It is related to.

2. Description of the Related Art Recently, with the spread of computers, printers for terminals have come into widespread use.

Among them, the inkjet recording method has less noise and
It has advantages such as easy colorization and excellent image quality. Among inkjet recording systems, there are those that utilize air flow, and for example, a configuration described in Japanese Patent Laid-Open No. 58-220758 is known. Below, Figure 3 (A
), (B) using the above conventional air flow 7
The ink L/1 nod recording head will be explained.

Figure 3 (A) shows the multi-nozzle heno 3 using air flow.
・7 A vertical cross-sectional view of the board, and FIG. 7(B) is a cross-sectional view taken along the line IB-IB. As shown in FIGS. 3(A) and 3(B), an air nozzle plate 3 made of an insulating material is attached to the open end side of the rectangular frame-shaped outer wall 2 of the body member 1. An ink nozzle plate 5 made of an insulating material is attached to the open end side of the shaped inner wall 4, and a narrow air passage 6 is formed between the ink nozzle plate 5 and the air nozzle plate. An air chamber 7 is formed around the outer wall 2 and inner wall 4 of the body member 1, which communicates with itself and around the air flow path 6. An ink chamber 8 is formed inside the ink nozzle plate 5 and the inner wall 4. The ink nozzle plate 5 is formed with a plurality of ink discharge ports 9-1 to 9-n, and the air nozzle plate 3 is formed with a plurality of air discharge ports 10-1 facing the ink discharge ports 91 to 9-n. ~10-n is formed. A common electrode 11 is provided on the outer surface of the air nozzle plate 3 at the outer periphery of the air outlet ports 10-1 to 10-n, and a common electrode 11 is provided on the outer periphery of the air outlet ports 10-1 to 10-n. Control electrodes 12-1 to 12-n are provided separately and independently on the outer periphery. Each electrode 11 and 12-1 to 12-n is connected to a signal source 13 so that a potential difference is applied to each electrode independently. One end of an air supply pipe 15 is communicated with an air supply port 14 formed on the back side of one side of the air chamber 7, and an ink supply pipe 17 is connected to an ink supply port 16 formed on the back side of the ink chamber 8. One end is connected. The air supply pipe 1 of the inkjet recording head configured as described above is
The other end of 5 is connected to an air supply source 18, and the ink supply pipe 1
The other end of the ink supply source I9 is connected to an ink supply source 19, and a constant pressure is applied from the air supply source 18 to the ink within the ink supply source I9.

The operation of the above configuration will be described below.

Air from the air supply source 18 is supplied to the air chamber 7 through the air supply port 14 through the air supply pipe 15 , and flows out into the air flow path 6 as an air layer at a constant flow rate, and this air flows through each air discharge port 1 .
0-1 to 10-n and each ink discharge port 9-1 to 9-n
Each air outlet 10-1~ while making a sharp bend in the vicinity.
It is discharged from 1 on. On the other hand, ink in the ink supply source 19 is supplied from the ink supply port 16 via the ink supply pipe 17 to the ink chamber 8 and is constantly kept in a groove, and is sent to the ink supply source 19 from the air supply source 18. Air pressure ink supply source 1
A constant pressure is applied to the ink in the ink chamber 9 and the ink chamber 8. As a result, the air pressure near the ink ejection ports 9-1 to 9-n that occurs when the ink jet recording device is not driven becomes approximately equal to the pressure inside the ink ejection ports 9-1 to 9-n, and the ink ejection ports 9-1 The ink meniscus generated at ~9-n remains stationary. And common electrode 1
When a potential difference is provided between 1 and the control electrodes 12-1 to 12-n,
The electrostatic force caused by this potential difference causes the ink discharge ports 9-1 to
The ink meniscus generated at 9-n is stretched in the direction of air discharge ports 10-1 to 10-n. Ink discharge ports 9-1 to 9-n and air discharge ports], 0-1 to 10
Since the air flow path 6 leading to the ink discharge ports 9-1 to 9-n has a rapid pressure gradient change due to the air flow,
When the meniscus of ink n is stretched beyond a certain length, it is rapidly accelerated and is ejected from the air ejection ports 10-1 to 10n.

Problems to be Solved by the Invention However, in the configuration of the conventional example as described above, the air discharge port 1
0-1 to 0-n, the flow rate of the air flowing out is somewhat different at each of the air discharge ports 10-1 to 10-n. In other words, among the air discharge ports 10-1 to lO-〇, the flow velocity of the air discharge port located on the air supply port 14 side] 0-1 side is farther away from the air supply port 14, and the air supply force is Air discharge port 1 on the lowering side
It becomes larger than the 0-n side.

This difference in flow velocity becomes larger as the number of air discharge ports 10-1 to 10-n increases. Conventionally, when actually manufacturing the air chamber 7, efforts have been made to make the air chamber 7 as large as possible and to minimize the above-mentioned tendency for non-uniform flow velocity, but this is still not sufficient. Moreover, it cannot cope with the miniaturization of ~RAD. This phenomenon appears as a difference in recording characteristics (responsiveness and recording density are positively correlated with flow velocity), and is the cause of variations among the air discharge ports 10-1 to 10-n. .

The present invention solves the problems of the prior art as described above, and allows the air flow speeds of a plurality of air outlets to be made approximately equal, thereby improving the recording characteristics between each air outlet. The object of the present invention is to provide an in-plane two-adjustment recording head which can achieve uniformity, and can also be made smaller and thinner.

Means for Solving the Problems - The first step of the technical solution of the present invention to achieve the recording purpose is to provide a nozzle plate having a plurality of ink ejection ports;
An air nozzle plate having a plurality of air ejection ports corresponding to the ink ejection ports, an air flow path formed between the ink nozzle plate and the air nozzle plate, and an air flow path provided in communication with the periphery of the air flow path. , an air chamber having an air supply port communicating with an air supply source, and an ink chamber provided inside the ink nozzle plate described in -1- and having an ink supply port communicating with the ink supply source; The volume of the portion on the side separated from the air supply port side portion is larger than the volume of the portion on the air supply port side.

and communicating the air supply port side portion of the air chamber and the remote side portion with respect to the air supply port side portion on both sides,
It is preferable that the volume of the portion extending in the direction in which the air discharge ports are arranged gradually increases from the air supply port side toward the one remote side portion.

According to the present invention, with the above configuration, it is possible to alleviate the air pressure loss caused by a decrease in the air supply force to the air outlet on the side remote from the air supply port in the air chamber, and to reduce the pressure loss between each air outlet. Since the pressure loss can be kept almost constant,
The air flow velocity of each air outlet can be made substantially constant. Furthermore, the overall volume of the air chamber can be made as small as possible.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described.

Figures 1 (A,) and (3) show the recording on the finkgenome in the first embodiment of the present invention, and Figure 1 (A,)
is a vertical cross-sectional view, and Figure 1 (B) is IB-IB in Figure 1 (A).
It is a cross-sectional view of the arrow.

In this embodiment, the same parts as those in the conventional example described above are designated by the same reference numerals, and the explanation thereof will be omitted, and only the different structures will be explained.

As shown in FIGS. 1(A) and (13), the air chamber 7 has a portion 7.1 having an air supply port 14 between one short side of the outer wall 2 and the inner wall 4, and a portion 7.1 having an air supply port 14 between the short side of the other side of the outer wall 2 and the inner wall 4. The air discharge ports 10-1 to 10-1 communicate with the separated side (opposite side) portion 7b to the supply port side portion 7a on both sides, and are connected between the picture surface sides of the outer wall 2 and the inner wall 4.
10-n along the arrangement direction, and the volume of the separated side portion 7b from the air supply port side portion 7a is larger than the volume of the air supply [-] side portion 7a. In other words, the volume of the air supply port side portion 7a is smaller than the volume of the remote side portion 71].

The operation of the above configuration will be described below.

Air in the air supply source 18 is supplied from the air supply port side to the air supply port side portion 7a of the air chamber 7 via the air supply pipe 15. This supplied air is divided into parts 7a and 7) along the direction in which the air discharges D1.01 to 10-n are arranged, as shown by arrows in FIG. 1(B), and separated parts 7b.
[7] The air flows into the air passage 6 from both sides and flows out from each air outlet 10-1 to 10-n. At this time, since the volume of the remote side portion 7b of the air chamber 7 is set to be larger than the volume of the air supply port side portion 7a as described above, conventionally, as the distance from the air supply port 14 increases, Almost no pressure loss occurs due to the decrease in the air supply force to the air discharge port 10.Therefore, the pressure loss between each air discharge port [0-1 to ton] is almost constant, and each air discharge port By making the air discharge ports 10-1 to 10-n substantially uniform, it is possible to improve the recording characteristics between the air discharge ports 10-1 to 10-n.

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

FIG. 2 shows an ink cartridge 11 according to a second embodiment of the present invention.
- It is a sectional view similar to FIG. 1(B), showing the recording head on the edge. In this embodiment, the air chamber 7 is formed such that the volume of the remote side portion 7b is larger than the volume of the air supply port side portion 7a, and the side portions 7a and 7b are communicated on both sides, and air is discharged. A portion 7c17d along the direction in which the outlets 10-1 to 1O-rl are arranged is formed so that its volume gradually increases from the air supply port side portion 7a to the remote side portion 7b side.

Therefore, according to this embodiment, each air discharge hole 1O-1
The pressure loss between 10-n and 10-n becomes more constant, the air flow velocity of each air outlet 10-1 to 10-n is made uniform, and the recording characteristics between each air outlet 10-1 to 10-n are improved. You can improve your performance.

In each of the above embodiments, the ratio of the volumes of the air supply port side portion 7a and the remote side portion 7b in the air chamber 7, and the portion 7c that communicates them in an annular shape.

Regarding the volume size of 7d, air discharge ports 101 to 1
It greatly depends on the diameter, number, pitch of 0-n, and the thickness and area of the air flow path 6, and the optimum relationship may be determined based on these.

As described above, according to this embodiment, the pressure loss of air to the air outlet 10 on the side remote from the air supply port 14 can be alleviated, and the air pressure loss can be uniformly distributed among the air outlets 10-1 to 10-n. Since it is possible to obtain an air flow at a high velocity, it is extremely effective when making the nozzle smaller or thinner for multi-nozzle inkjet recording.

Effects of the Invention As described above, according to the present invention, the volume of the part on the side separated from the air supply port side part is larger than the volume of the part on the air supply port side of the air chamber. It alleviates the air pressure loss caused by the drop in air supply force to the air outlet on the side that is remote from the air supply inlet, makes the pressure loss between each air outlet almost constant, and reduces the air flow velocity at each air outlet to about the same level. It can be kept constant. Therefore, it is possible to make the recording characteristics uniform among the air discharge ports, and the overall volume of the air chamber can be made as small as possible, so that it is possible to make the device smaller and thinner.

Further, the air supply port side portion of the air chamber and the remote side portion from the air supply port side portion are communicated on both sides, and the portion along the arrangement direction of the air discharge ports is from the air supply port side portion to the remote side portion. The above effect can be further improved by gradually increasing the volume as the temperature increases.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) show an ink jet recording head according to a first embodiment of the present invention, in which FIG. 1(A) is a longitudinal sectional view, and FIG. 1(B) is an IB of FIG. -IB arrow sectional view, FIG. 2 shows an ink jet recording head in the second embodiment of the present invention, and FIG. 3(A) and FIG. A conventional inkjet recording head is shown in which FIG. 1A is a longitudinal cross-sectional view and FIG. 1B is a cross-sectional view taken along the line IB--IB in FIG. 1...Body member, 2...Outer wall, 3...Air nozzle plate, 4...Inner wall, 5...Ink nozzle plate, 6-mount air flow path,
7. Air chamber, 8. Ink chamber, 9-1 to 9-n...
Ink discharge port, 10-1 to 10-n... air discharge port,
DESCRIPTION OF SYMBOLS 11... Electrode, 12... Control electrode, 13... Signal source, I4... Air supply port, 15... Air supply pipe, 16
...Ink supply port, 17...Ink supply pipe, 18...
- Air supply source, 19... Ink supply source.

Claims (2)

[Claims] (1) An ink nozzle plate having a plurality of ink discharge ports, an air nozzle plate having a plurality of air discharge ports corresponding to the ink discharge ports, and air formed between the ink nozzle plate and the air nozzle plate. a flow path, an air chamber provided in communication around the air flow path and having an air supply port communicated with an air supply source, and provided inside the ink nozzle plate;
The ink chamber includes an ink chamber in which the ink supply port is communicated with an ink supply source, and the air chamber is formed such that a volume of a portion of the air chamber on the side remote from the air supply port side is larger than a volume of the portion of the air chamber on the air supply port side. inkjet recording head. (2) The air supply port side part of the air chamber and the spaced part from the air supply port side part are communicated on both sides, and the part along the direction in which the air discharge ports are arranged is from the air supply port side part to the spaced side part. The inkjet recording head according to claim 1, wherein the inkjet recording head is formed so that its volume gradually increases as it approaches the portion.