JPH0468150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording head, and more particularly to a liquid jet recording head capable of improving recording speed.

2. Description of the Related Art Conventionally, various so-called liquid jet recording methods have been developed or put into practical use in which liquid is ejected from a liquid ejection port to record characters, figures, etc. on a recording material. Among these, a particularly recent trend is that droplets are ejected only when necessary for recording, so there is no need for means such as a means to collect unnecessary liquid or a high-voltage power supply for deflecting the droplets. On-demand liquid jet recording methods are attracting attention.

Although the on-demand type liquid jet recording apparatus has the above-mentioned great advantages, in order to perform high-speed recording, droplets must also be ejected at a high frequency. Furthermore, in order to improve the frequency characteristics of the droplets, liquid equivalent to the amount of the ejected droplets must be instantly replenished. However, in order to quickly replenish the liquid, if no side wall is provided for each discharge port to provide a dedicated liquid flow path between each discharge port,
Unnecessary droplet ejection energy is propagated to adjacent ejection ports, making it difficult to accurately land the droplets on the recording material. In addition, if a side wall is provided between adjacent ejection ports to form a dedicated liquid flow path, and each ejection port is separated and independent, unnecessary droplet ejection energy will not be transmitted to the adjacent ejection ports, but each ejection port will The problem of rapid replenishment of liquid into the corresponding liquid flow path remains unsolved.

The present invention has been made in view of these points, and
It is an object of the present invention to provide a liquid jet recording head having a structure that allows the liquid to be quickly refilled and having good frequency characteristics of droplet ejection.

The above-mentioned conventional problems will be further explained using figures, and the concept of a means for solving the above-mentioned problems according to the present invention will be explained using figures.

In what follows, for example, the German Opening (OLS) No.
An example of a device applied to the recording method described in Publication No. 2843064 and Publication No. 2944005 will be explained.
The concept of the present invention includes not only devices applied to such a recording method, but also other drop-on-demand liquid ejecting devices using piezoelectric elements, for example.

Figure 1 shows a discharge port (orifice) for discharging liquid to form flying droplets, a liquid flow path communicating with the discharge port, and an energy acting part that constitutes at least a part of the liquid flow path. A heat acting part (energy acting part) of a liquid jet recording head (recording head) of a liquid jet recording device, which has a heat acting part as a heat acting part, and an electrothermal converter that generates heat applied to the liquid in the heat acting part.
FIG. 3 is a schematic partial plan view showing the vicinity. 101 is a substrate, 102 is a side wall, and 103 is an electrothermal converter. As shown in FIG. 1, an electrothermal converter 10 serves as a discharge energy generator that supplies energy for discharging droplets from a discharge port (orifice).
3 are separated from each other by the side walls 102.

2a to 2c are schematic partial cross-sectional views taken along the dashed line X-X' shown in FIG. 1, respectively. FIG. 2a shows a conventional liquid jet recording head, and FIGS. 2b and 2c each illustrate a liquid jet recording head of the present invention.

In FIGS. 2a to 2b, 201 is a substrate, 202 is a side wall, 203 is an electrothermal converter, and 2
04 is an orifice, and 205 is a plate (hereinafter referred to as an orifice plate) on which the orifice 204 is provided.

As shown in FIG. 2a, in the conventional type, the side wall 202 is formed continuously from the substrate 201 to the orifice plate 205, and the side wall 202 and the substrate 205 are formed continuously.
1 or the orifice plates 205 are in close contact with each other without any gaps or the like.

On the other hand, in the case of the present invention shown in FIG. 2b, between the side wall 202 forming the liquid path and the orifice plate 205, and in the case shown in FIG.
A gap is provided between the side wall 202 and the substrate 201, each serving as an auxiliary liquid supply port.In the present invention, the loss of the original power of energy for the formation of flying droplets is reduced as much as possible, and The replenishment of liquid is not limited to the liquid flow path corresponding to one orifice;
The purpose is to perform liquid replenishment quickly by also performing the liquid replenishment through the gaps connecting the respective liquid paths as shown in FIG.

That is, the liquid jet recording head of the present invention includes a plurality of ejection ports for ejecting liquid, a liquid path communicating with each of the plurality of ejection ports, and an ejection port forming at least a part of the liquid path. In a liquid jet recording head having an energy acting section and an ejection energy generating body that generates energy for ejecting the liquid to act on the liquid in the ejection energy acting section, each of the liquid paths is connected to the liquid path. It is characterized by communicating through an auxiliary liquid supply port provided at or near the discharge energy acting part of the wall to be formed. According to the present invention, loss of energy for flying droplet formation is prevented, and
Since the amount of liquid equivalent to the ejected droplets can be refilled quickly, it is possible to provide a liquid jet recording head that has good frequency characteristics of droplet ejection and is suitable for high-speed recording.

The liquid jet recording head of the present invention will be explained in more detail.

FIGS. 3a and 3b are diagrams showing an example of how to provide a gap, and each is a schematic perspective partial view. In the figure, 301 is a substrate, 302 is a side wall,
303 is an electrothermal converter, 304 is an orifice, 3
05 is an orifice plate. In the figure, side wall 30
2, the rough hatched portion at the top is the portion that comes into close contact with the orifice plate 305, and the non-shaded portion is the gap portion.

FIG. 3a shows an example in which a portion of the side wall 302 is formed low. FIG. 3b shows an example in which the side wall 302 is lowered one step from the middle.

What is shown in Figures 3a and 3b is the second
Although it is of the type shown in Figure b, it could equally well be of the type shown in Figure 2c.

Furthermore, one of the preferred embodiments of the present invention will be explained with reference to the drawings.
Explain one thing.

4 to 6 are diagrams for explaining this embodiment, in which FIG. 4 is a schematic cross-sectional view, FIG. 5 is a schematic perspective assembly view, and FIG. 6 is a schematic partial plan view. be.

4 to 6, 401 is a substrate, 402 is a side wall, 403 is a heat acting part, 404 is an orifice, 405 is an orifice plate, 406 is an outer wall, 407 is a rear wall plate, and 408 is a heating resistor. layer, 4
09 is an electrode layer, 410 is a wiring, and 411 is a protective layer.

The manufacturing procedure of this embodiment will be briefly explained below.

The surface was thermally oxidized to form _two SiO layers with a thickness of 3 μm.
100 μm of the Si substrate was removed by etching. Next, a Ta layer with a thickness of 2000 Å was laminated as a heating resistor layer 408, and an Al layer was laminated with a thickness of 1 μm as an electrode 409, and then a heat generating part (heater) array having a shape of 60 μm×100 μm was formed at a pitch of 200 μm by a photolithography process.
In addition, as a film to prevent Ta layer from oxidation and penetration of ink liquid, and to resist mechanical shock caused by bubbles generated when liquid receives thermal energy, _two SiO layers with a thickness of 0.5 μm are used.
A protective layer 411 was formed by sequentially laminating SiC layers 1 μm thick by sputtering.

Next, the side wall 40 of the heater as shown in FIG.
2 (as in FIGS. 3a and 3b, the roughly shaded portion is in close contact with the orifice plate) and a liquid flow path was formed. The width of the liquid flow path is 100 μm, the distance from the common liquid chamber to the heater is 750 μm, the length of portion a in FIG. 6 is 500 μm (therefore, the length of portion b is 250 μm), and the height of side wall 402 is The portion that comes into close contact with the orifice plate 405 was formed to have a thickness of 50 μm. The gap between the side wall 402 and the orifice plate 405 was 20 μm.

The orifice 404 was formed directly above the heater, had an orifice diameter of 40 μm, and was formed by etching a 30 μm thick NiCr plate.

A rear wall plate 407 and two outer walls 406 were formed, and one of the outer walls 406 was provided with a through hole and a supply pipe for supplying ink.

5 μs for the embodiment of the present invention manufactured as described above.
When driven by applying a rectangular voltage of , the highest frequency at which droplets were ejected was 8.5KHz.

A model in which part a of the side wall was in close contact with the orifice plate as shown in Fig. 6 was manufactured, and the dimensions of each part were made the same as in this embodiment, and the highest frequency at which droplets were ejected was similarly measured, and it was 3KHz. It was hot.

As described above, in this embodiment, the gap provided in the side wall was able to significantly improve the maximum frequency limit compared to the conventional one.

Incidentally, as a result of manufacturing many modified examples, it is better to have the gap near the heat generating part, and it is generally better to provide the gap within 1 mm, more preferably within 500 μm. Furthermore, when providing the gap within the liquid flow path, it is more preferable to provide the gap on the opposite side of the orifice.

As described above, the gap may be provided between the orifice plate and the side wall, or between the side wall and the substrate, or the gap may be provided in the side wall. Further, the auxiliary liquid supply port may be located not on the main liquid supply side but on the terminal end side of the liquid flow path.

The size of the gap should be determined appropriately depending on the size of the droplets to be ejected, the size of the liquid flow path, etc., the density of the ejection port, the type of liquid (ink) used, etc. , it goes without saying that the size should be set to such an extent that it is not affected by the droplet ejection energy of adjacent ejection ports.

Further, in the present invention, the member provided with the discharge ports is referred to as an orifice plate, but this does not need to be plate-shaped.

As described above, FIGS. 3a and 3b each schematically show an example of how to provide a gap. Therefore, it goes without saying that the units shown in FIGS. 3a and 3b may be adjacent or repeated. In addition, on both sides, the side other than the terminal end of the liquid flow path may have a flow path, a liquid chamber, etc. for supplying liquid to the liquid flow path, even if it is not cut to the position shown in the figure. .

[Brief explanation of the drawing]

Figure 1 is a schematic partial plan view of the recording head, Figure 2 is a schematic partial plan view of the recording head;
Figures a to 2c are schematic cross-sectional partial views, respectively.
FIG. 2a shows an example of a conventional recording head, and FIGS. 2b and 2c each show an example of the recording head of the present invention. 3a and 3b are schematic perspective partial views of the recording head section of the present invention, and FIGS. 4 to 6 are diagrams for explaining embodiments of the present invention, and FIG. FIG. 5 is a schematic cross-sectional view, FIG. 5 is a schematic perspective assembly view, and FIG. 6 is a schematic partial plan view. 101, 201, 301, 401...Substrate, 1
02,202,302,402...Side wall, 10
3,203,303,403...Heat action part, 20
4,304,404...orifice, 205,3
05,405...Orifice plate, 406...Outer wall, 407...Rear wall plate, 408...Heating resistance layer, 409...Electrode layer, 410...Wiring, 411
...protective layer.

Claims (1)

[Scope of Claims] 1. A plurality of ejection ports for ejecting liquid, and a liquid path communicating with each of the plurality of ejection ports,
A liquid ejecting recording head comprising: an ejection energy acting part forming at least a part of the liquid path; and an ejection energy generator generating energy for ejecting the liquid and acting on the liquid in the ejection energy acting part. . A liquid jet recording head, wherein each of the liquid paths communicates with each other via an auxiliary liquid supply port provided at or near a portion of a wall forming the liquid path where an ejection energy acts. 2. The liquid jet recording head according to claim 1, wherein the ejection energy application section includes an electrothermal converter that generates heat. 3. The auxiliary liquid supply port is formed by a step provided on the wall of the liquid path on the upstream side of the liquid flow relative to the discharge energy acting part and within 1 mm from the end of the discharge energy acting part. A liquid jet recording head according to claim 1. 4. The liquid jet recording head according to claim 1, wherein the direction of the liquid path is different from the surface direction of the ejection port. 5. The liquid jet recording head according to claim 1, wherein the liquid is ink used for recording, and each of the liquid paths is filled with the ink.