JP2000025219A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure clear print by filling ink more uniformly and improving ink ejection from a nozzle provided for each pressurizing chamber. SOLUTION: A common channel 5 extending from an ink reservoir 4 is coupled, on the forward end side thereof, with a loop channel 6 which is coupled, on the root side, with the ink reservoir 4. Consequently, ink flows from the ink reservoir 4 through the loop channel 6 to the forward end side of the common channel 5. Pressure difference of ink can thereby reduced between the forward end side remote from the ink reservoir 4 and the root side close to the ink reservoir 4 in the common channel 5. According to the arrangement, any pressuring chamber 7 can be filled with ink smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for an ink jet printer.

[0002]

2. Description of the Related Art In a so-called on-demand type ink-jet printer, an ink-jet head used for discharging ink droplets usually has a large number of pressurizing chambers on a single substrate and ink-jets which are connected to the pressurizing chambers. Nozzle is provided. The pressure chamber is provided with a piezoelectric element, and the pressure chamber is pressurized by the piezoelectric element, so that an ink droplet is ejected from a nozzle.

Specifically, for example, as shown in FIG.
An independent piezoelectric element is provided for each of the pressure chambers 91a on a substrate 91 on which a plurality of pressure chambers 91a are arranged, directly above each of the pressure chambers 91a via a vibration plate 92 having at least an upper surface made conductive. The film 93 and the upper electrode 94 are stacked in this order. On the lower surface side of the substrate 91, a nozzle plate 95 in which a plurality of nozzles 95a corresponding to the respective pressure chambers 91a are formed is stacked.

In the ink jet head 9 having such a configuration, the conductive upper surface of the diaphragm 92 is used as a lower electrode, and printing data is printed between the lower electrode and an arbitrary upper electrode 94 among a plurality of electrodes. When the electric field is applied in accordance with the above, the piezoelectric film 93 between both electrodes is bent, and the pressurizing chamber 91 a immediately below is pressed via the vibration plate 92.

[0005] By this pressurization, the pressurizing chamber 91a
A predetermined amount of ink pre-filled therein is ejected as ink droplets from the connected nozzle 95a, and printing is performed by repeating this process.

Each of the plurality of pressurizing chambers 91a communicates with a common flow path (not shown), and ink is supplied from the common flow path to each pressurizing chamber 91a.

[0007]

The common flow path for supplying ink to each pressurizing chamber is a long flow path, and the pressurizing chambers are arranged along the common flow path. Ideally, the filling of the ink from the common flow channel into the pressure chambers should be performed equally to all the pressure chambers. The pressure chamber is easily filled with ink,
There is a problem that it is difficult for the pressurized chamber communicated with the downstream side of the common flow path to be filled with ink.

The present invention solves the above problem and provides an improved ink jet head in which any of a plurality of pressure chambers communicated with a common flow path is filled with ink satisfactorily. That is.

[0009]

According to the first aspect of the present invention,
An ink jet head for performing printing by repeating ejection of ink droplets, an ink reservoir for temporarily storing ink to be supplied, a longitudinal common flow path, a common flow path having a base side communicated with the ink reservoir. And a plurality of pressurizing chambers, each of which is supplied with ink from a common flow path, a nozzle for discharging ink droplets communicated with each pressurizing chamber, and a tip of the common flow path and an ink reservoir. And a loop flow path.

According to a second aspect of the present invention, the common flow path includes:
2. The ink jet head according to claim 1, further comprising a plurality of flow paths arranged in parallel, wherein respective ends of the plurality of flow paths are communicated with each other by a loop flow path.

According to a third aspect of the present invention, there is provided the ink reservoir,
The common flow path and the loop flow path are provided on one substrate, and the common flow path and the loop flow path are formed in upper and lower two layers in the thickness direction of the substrate. 2. The inkjet head according to item 1.

According to the first aspect of the invention, the ink from the ink reservoir is supplied to the front end side of the common flow path through the loop flow path. Therefore, it is possible to reduce the pressure difference of the ink filled in the flow path between the base side of the common flow path connected to the ink reservoir and the tip side of the common flow path remote from the ink reservoir. When the pressure difference of the ink in the common flow path is reduced, the filling of the ink from the common flow path to each of the pressure chambers is less likely to vary from one pressure chamber to another.

Normally, the further away from the ink reservoir, the lower the pressure of the ink in the common flow path, and there is a drawback that the ink is less likely to be filled in the pressurized chamber connected to the tip of the common flow path. By connecting the loop flow path as in the above configuration, the ink pressure at the tip end side of the common flow path can be increased, and the above-mentioned drawback is solved.

According to the second aspect of the present invention, since the tips of the plurality of common flow paths are communicated with each other through the loop flow path, the ink pressures at the tips of the plurality of common flow paths can be made substantially equal.

According to the third aspect of the present invention, since the common flow path and the loop flow path are formed in upper and lower two layers, the area of the ink jet head in plan view does not increase even if the loop flow path is provided. And a compact inkjet head can be realized.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an illustrative view showing an entire configuration of an ink jet head 1 according to an embodiment of the present invention.

The ink jet head 1 is formed on a single substrate 2. An ink reservoir 4 for temporarily storing ink supplied from a supply port 3 is provided in the substrate 2. In this embodiment, the ink reservoir 4 has an isosceles triangular shape having a low height in plan view. A plurality of (six in this embodiment) common flow paths 5 and loop flow paths 6 extend downward from the bottom of the isosceles triangular ink reservoir 4. The common flow path 5 and the loop flow path 6 are formed in two layers, upper and lower, in the thickness direction of the substrate 2.
In FIG. 1, the two flow paths are shown as one flow path because they overlap.

On both sides of the common flow path 5, a plurality of pressurizing chambers 7 arranged along the common flow path are provided. In addition,
Although the number of the pressurizing chambers 7 is omitted in the figure, in actuality, 21 pressurizing chambers 7 are provided on both sides of one common flow path 5 respectively. That is, in this embodiment,
Each loop flow path 6 is connected to 21 pressurizing chambers 7 on both sides, and has 6 common flow paths 5. Therefore, (21 + 21) × 6 = 252 pressurizing chambers 7 Is provided. By the way, the size of the substrate 2 is 50 mm in width,
The length is 19 mm.

FIG. 2 is a partial sectional view taken along the line AA of FIG. 1, and FIG. 3 is a partial sectional view taken along the line BB of FIG.

Referring to FIG. 2 and FIG. 3, the common channel 5 and the loop channel 6 are formed in the substrate 2 in the lower and upper two layers in the thickness direction of the substrate 2 as described above. . More specifically, the common flow path 5 is formed on the lower layer side, and the loop flow path 6 is formed on the upper layer side. The root side of the common flow path 5 is communicated with the ink reservoir 4. The root side of the loop channel 6 is also connected to the ink reservoir 4.
The respective ends of the common flow path 5 and the loop flow path 6 communicate with each other as shown in FIG. As a result, the ink reservoir 4, the common flow path 5, and the loop flow path 6 communicate with each other.

In FIGS. 2 and 3, reference numeral 11 denotes a nozzle plate, and reference numeral 12 denotes a simplified upper plate. Actually, the upper surface plate 12 does not include such a single plate but includes a vibration plate, a piezoelectric film, an upper electrode, and the like.

FIG. 4 is a diagram illustrating the ink flow path taken out, in which a part of the common flow path 5 and a part of the loop flow path 6 on the tip side is schematically illustrated.

Referring to FIGS. 3 and 4, a pressurizing chamber 7 is connected to a common flow path 5 formed in the substrate 2 via a supply path 13. The pressurizing chambers 7 are arranged at substantially equal intervals on both sides of the common flow channel 5 along the length direction of the common flow channel 5.

Each of the pressurizing chambers 7 is connected to a nozzle flow path 14 which is a funnel-shaped, tapered flow path. At the tip of the nozzle flow path 14, a nozzle plate 11 is formed. Nozzle 15 communicates.

The ink flowing through the common flow path 5 is supplied to the supply path 13
Into the pressure chamber 7 via When pressure is applied to the pressure chamber 7 by controlling the vibration plate included in the upper surface plate 12, the ink filled in the pressure chamber 7 passes through the nozzle flow path 14 and is ejected from the nozzle 15 as ink droplets. . The ejected ink is replenished from the common flow path 5 to the pressurizing chamber 7 via the supply path 13.

By the way, as described above, 21 pressurizing chambers are connected to both sides of the common flow path 5, and it is ideal that all the pressurizing chambers 7 are filled with ink evenly. It is a target. However, actually, the ink reservoir 4
, A pressurizing chamber 7 connected near the root side of the common flow path 5
Are easily filled with ink, and the pressure chamber 7 connected to the tip end of the common flow channel 5 is not easily filled with ink. However, when the loop flow path 6 is communicated with the leading end side of the common flow path 5 as in this embodiment, the ink flows from the ink reservoir 4 to the leading end side of the common flow path 5 through the loop flow path 6. Flows. Therefore, the ink pressure on the leading end side of the common flow channel 5 is higher than in the case where the loop flow channel 6 is not provided, and the difference in ink pressure due to a difference in location in the common flow channel 5 is reduced.

Accordingly, as the distance from the ink reservoir 4 increases, the ink pressure in the common flow path 5 decreases, and the disadvantage that the pressure chamber 7 connected to the end of the common flow path 5 is hardly filled with ink is eliminated. I have.

Since the loop flow path 6 is formed in the upper layer of the common flow path 5, there is no increase in area due to the provision of the loop flow path 6 in plan view. Therefore, it is not necessary to increase the area of the substrate 2 (see FIG. 1), and a compact inkjet head is realized.

FIG. 5 is an illustrative view showing an overall configuration of an ink jet head 20 according to another embodiment of the present invention, and a main portion of the configuration is shown in a plan view.

Referring to FIG. 5, an ink jet head 20 has an ink reservoir 4 and six common flow paths 5 formed on a substrate 2. A plurality of pressurizing chambers 7 are arranged on both sides of each common flow path 5 along its length direction. These configurations are the same as those of the inkjet head 1 described in the above embodiment.

The feature of this embodiment is that a loop channel 6 parallel to the common channel 5 is provided, and the root side of the loop channel 6 is communicated with the ink reservoir 4. The front end side is a loop flow path 6 ′ that is bent at a substantially right angle in plan view, and communicates with the front end side of each common flow path 5. Thereby, a plurality (6 in this embodiment)
) Of the common flow path 5 is connected to one loop flow path 6,
They are interconnected by 6 '.

With this configuration, the ink in the ink reservoir 4 is supplied to the leading end of each common flow passage 5 through the loop passage 6, so that the ink pressure at the leading end of each common flow passage 5 decreases. Can be prevented. As a result, it is possible to keep the ink filling state in the large number of pressurizing chambers 7 almost uniformly.

Since the loop channels 6 and 6 'in the ink jet head 20 are connected to the six common channels 5, ink is supplied to the leading ends of the six common channels 5. A slightly thicker flow path may be used for ease.

In the embodiment shown in FIG. 5, the loop flow path 6 extending in parallel with the common flow path 5 is disposed at the right end of the substrate 2, but is not limited to this. , A loop channel 6 is formed, and 3
The common flow path 5 may be arranged in parallel for each book. In this case, the tip of the loop channel 6 may be configured to branch left and right in plan view and communicate with the tip of each common channel 5.

In the embodiment shown in FIG. 5, the loop flow path 6 is arranged only at the right end of the substrate 2, but is not limited to this, and may be arranged symmetrically at the right end and the left end.

When the loop channels 6 are arranged in parallel with the common channel 5 as in each of the embodiments, the loop channels 6 can be formed simultaneously with the formation of the common channel 5 in the substrate 2.
An inkjet head that can be easily manufactured can be provided.

The above description is a description of a typical embodiment, and the present invention is not limited to the embodiment described above, and various changes can be made within the scope of the claims.

[0039]

According to the present invention, the ink can be more evenly filled in the multiple pressurizing chambers provided in the ink jet head, and the ink can be supplied from the nozzles provided in each pressurizing chamber. It is possible to provide an ink jet head that discharges well and can perform clear printing.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing an overall configuration of an inkjet head according to an embodiment of the present invention;

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is an illustrative partial perspective view showing a relationship among a common channel 5, a loop channel 6, and a pressurizing chamber 7.

FIG. 5 is an illustrative plan view showing the overall configuration of an inkjet head according to another embodiment of the present invention.

FIG. 6 is an illustrative sectional view showing a configuration related to a pressurizing chamber of the inkjet head.

[Explanation of symbols]

 Reference Signs List 1,20 inkjet head 2 substrate 4 ink reservoir 5 common flow path 6 loop flow path 7 pressurizing chamber 14 nozzle flow path 15 nozzle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koichi Baba, Inventor Koichi Baba 1-2-28, Chuo-ku, Osaka, Japan Inside Mita Kogyo Co., Ltd. (72) Inventor Keisuke Sumita 1-2-2, Tamazo, Chuo-ku, Osaka, Osaka No. 28 Inside Mita Kogyo Co., Ltd. (72) Junko Yamada, Inventor Junko Yamada 1-2-2, Takumazo, Chuo-ku, Osaka, Osaka Prefecture Inside Mita Kogyo Co., Ltd. No. 28 Inside Mita Kogyo Co., Ltd. (72) Inventor Masatake Hayashi 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka No. 28 Inside Mita Kogyo Co., Ltd. No. 28 Inside Mita Kogyo Co., Ltd. (72) Inventor Koji Kuramasu 1-2-2 Tamatsuzo, Chuo-ku, Osaka-shi, Osaka F-term inside Mita Kogyo Co., Ltd. (reference) 2C057 AF24 AF34 AF61 AG44 BA04 BA14

Claims (3)

[Claims] An ink jet head for performing printing by repeating ejection of ink droplets, the ink jet head temporarily storing ink to be supplied, and a longitudinal common flow having a base side communicated with the ink jet. A plurality of pressurizing chambers arranged along the common flow path, each of which is supplied with ink from the common flow path, a nozzle for discharging ink droplets communicated with each pressurizing chamber, and a tip of the common flow path. An ink jet head comprising: a loop flow path communicating with an ink reservoir. 2. The loop according to claim 1, wherein the common flow path includes a plurality of flow paths arranged in parallel, and each end of the plurality of flow paths is communicated with a loop flow path. Inkjet head. 3. The ink reservoir, the common flow path and the loop flow path are provided on one substrate, and the common flow path and the loop flow path are formed in two layers in the thickness direction of the substrate. The ink jet head according to claim 1, wherein: