JPS588661A - Liquid jet type recording head - Google Patents

Abstract

PURPOSE:To form a pattern as fine as possible simply as desired by hardening a photosensitive resin to form a main part of the wall surface of a liquid passage with a heat generating body provided at a heat action part composing a part thereof. CONSTITUTION:Heat generating elements 2 are arranged on a substrate 1 made of glass or the like to generate the output for discharging a liquid and a dry film photoresist 3 is laminated thereon. When the product is exposed to light after a photo mask 4 with a specified pattern 4p is stacked thereon, the exposed part thereof is hardened by the polymn. to become insoluble in a solvent. Then, it is immersed into a volatile organic solvent to form a liquid passage by removing non-dissolved parts and further hardened by a thermal polymerization. A dry film photoresist 5 is laminated on the hardened film 3H in such a manner as not to penetrate thereinto and a photo mask 6 with a pattern 6p for forming a discharge port 7 is stacked thereon. Then, it is exposed to light to harden in the same way, followed by dissolution in a solvent and thermal polymerization. In this manner, a head is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet head (liquid jet recording head), and more particularly, to an inkjet head for generating recording ink droplets for use in a so-called inkjet recording method using thermal energy.

Ink dimets generally include a fine ink liquid ejection outlet (orifice), an ink liquid flow path, an ink liquid ejection force effecting part (heat effecting part) provided in a part of this ink liquid flow path, and a heating element. 0 Conventionally, the method of creating such an inkjet head is to form fine grooves on a slope of glass or metal by cutting or etching, and then attach the plate with the grooves to another plate with ejection ports. A method is known in which a liquid flow false path is formed by joining a plate on which a liquid flow is formed.

However, in the head made by such conventional method,
The roughness of the inner wall surface of the liquid flow path to be cut is too thick, or distortion occurs in the liquid flow path due to the difference in etching rate, making it difficult to obtain a liquid flow path with constant resistance. Variations tend to occur in the ink ejection characteristics of the heads. Another disadvantage is that the plate tends to chip or crack during cutting, resulting in a poor manufacturing yield. When etching is performed, there are many manufacturing steps, which is disadvantageous in that it increases manufacturing costs.

Furthermore, common shortcomings of the above-mentioned conventional methods include a grooved plate with grooves forming liquid flow paths and a lid plate equipped with a heating element (heating element) that generates thermal energy that acts on the liquid ink. One problem is that it is difficult to align the respective positions when laminating them together, resulting in a lack of mass productivity.

These points become more serious problems especially in the case of an inkjet head of the type in which the liquid flow path is not straight but has a curved portion due to the design. Therefore, the development of an inkjet head having a structure that solves these drawbacks is eagerly awaited.

The present invention has been made in view of the above-mentioned drawbacks, and aims to provide an inkjet head that is precise, durable, and highly reliable. This is also an object of the present invention.

Furthermore, it is another object of the present invention to provide an inkjet having a multi-array type of fine ink ejection nozzles in a simple manner.

The inkjet head of the present invention that achieves the above objectives has an ejection opening at the end of the liquid flow direction for ejecting the liquid to form flying droplets, and is bent in the middle. A liquid flow path, a heat acting part that forms at least a part of the liquid flow path and where the liquid filling the inside undergoes a thermal action and undergoes a state change, and a heat acting part for transmitting heat to the liquid filling the heat acting part. It is characterized in that it has a heating element that generates heat and a step, and its end portion on the wall surface of the liquid flow path is formed by curing a photosensitive resin.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention are schematic diagrams for explaining the structure of a head and its manufacturing procedure in detail with reference to the drawings.

First, as shown in FIG. 1, a heating element (electrothermal conversion element) 2 as a jetting force generating element is placed on a suitable substrate 1 such as glass, ceramics, plastic, or metal 2.
The heating element 2 as the liquid ejection force generating element generates a liquid ejection force by heating the ink liquid in the vicinity. .

Note that these elements 2 are connected to a signal input electrode i5, which is not shown.

Next, after cleaning and drying the surface of the substrate 1 on which the element 2 is provided, the surface of the substrate 1 on which the element 2 is provided is placed on the substrate surface IA shown in FIG. 2 (a).
), (b), dry film photoresist 3 (film thickness, about 25 μm to 100 μm) is a photosensitive resin having a shape humidified at about 80° C.
μ) to hO, 5~0.4f/f'j-(D speed, 1~3
(Laminated under pressure conditions of the package.

Incidentally, FIG. 2(b) is a cut plane corresponding to the x, x' line cut print in FIG. 2(a).

△ At this time, the dry film photoresist 3 is placed on the substrate surface I
It is crimped and fixed to A, and will not peel off from the substrate surface IA even if some pressure is applied thereafter.

Subsequently, as shown in FIG. 3, a photomaster 4 having a predetermined pattern 4P is overlaid on the dry film photoresist 3 provided on the substrate surface IA. Exposure (arrow in the figure) is performed by At this time, the pattern 4P sufficiently covers the region of the heat generating element 2 on the substrate 1, and the light from the light source 7 does not pass through this pattern 4P. Therefore, the dry film photoresist 3 in the area covered by the pattern 4P is not exposed. Further, when exposure is performed at this time according to the installation position of the heating element 2 and the alignment of the pattern 4P, the photoresist 3 outside the area of the pattern 4P undergoes a polymerization reaction and hardens, becoming insoluble in the solvent. On the other hand, the photoresist 3 that was not exposed and is surrounded by a broken line in the figure is not cured and remains soluble in the solvent. After the exposure operation, the dry film photoresist 3 is immersed in a volatile organic solvent, such as trichloroethane, to remove unpolymerized (
After the uncured photoresist 7 is dissolved and removed, the cured photoresist film 3H that has hardened and fallen on the substrate 1 is further cured for the purpose of improving the solvent resistance. The method is preferably thermal polymerization (heating at 130° C. to 160° C. for about 10 to 60 minutes), ultraviolet irradiation, or a combination of both.

The external appearance of the intermediate product formed through the above steps is shown in a perspective view in FIG.

Next, after cleaning and drying the surface of the cured photoresist film 3H of the intermediate product shown in FIG. Film photoresist 5 (film thickness, approx. 251μ~
iooμ) at a speed of 0.5-0.4 f/min, 0.11
Laminate under pressure conditions below v/d) (Figure 5)
. In this step, the photoresist 5 must be prevented from drooping into the liquid flow path where the dry film photo 2 is provided on the surface of the cured resist film 3H. Therefore, since sagging of the photoresist 5 occurs at the laminating pressure shown in the previous process, the laminating pressure is set to 0.1 level or less.

Another method is to provide a clearance equal to the thickness of the resist film 3H in advance and press the resist film 3H.

At this time, the dry film photoresist 5 is the cured film 3.
It is crimped and fixed to the H surface, and will not peel off even if some external pressure is applied thereafter.

Subsequently, as shown in FIG. 6, a photomask 6 having a predetermined pattern 6P is superimposed on the newly provided dry film photoresist 5, and then the photomask 6 is exposed to light from above. Note that the pattern 6P corresponds to a region that will later constitute a discharge port, and does not transmit light. Therefore, the dry film photoresist 5 in the area covered by the pattern 6P is not exposed.

Further, at this time, it is necessary to align the installation position of a heating element (not shown) provided on the substrate 1 with the pattern 6P using a well-known method.

As described above, when the photoresist 5 is exposed, the pattern 6
The photoresist 5 outside the P region undergoes a polymerization reaction, hardens, and becomes insoluble in the solvent. On the other hand, the photoresist 5 that has not been exposed to light is not cured and remains soluble in the solvent.

After the exposure operation, the dry film photoresist 5 is immersed in a volatile organic solvent, such as trichloroethane, to form unpolymerized (uncured) recesses shown in 7. Thereafter, the cured photoresist film 5H left on the previous resist film 3H is further hardened with the aim of improving the solvent resistance. The method is thermal polymerization (130℃~1
It is preferable to heat the film at 60° C. for about 10 to 60 minutes, or to irradiate it with ultraviolet rays, or to use a combination of both.

The holes formed in the cured photoresist film 5H in this manner become liquid discharge lowers. Then, a predetermined liquid supply pipe is connected to the liquid supply port 8, and the head manufacturing process is completed.

Various effects of the present invention described in detail above can be listed as follows.

1. The main part of head production is based on the so-called printing technology, so it is extremely easy to form the detailed parts of the head in a desired pattern. In addition, a large number of heads with the same configuration can be processed at the same time, and the number of manufacturing steps is relatively small, resulting in good productivity.

3. The main components can be easily and reliably aligned, and heads with high dimensional accuracy can be obtained at a high yield.

) 4. A high-density multi-array in-air jet head can be obtained by a simple method.

5. Continuous and mass production is possible.

6. Since there is no need to use an etching solution (a strong acid such as hydrofluoric acid), it is also superior in terms of safety and hygiene.

7. Since there is no need to use an adhesive, the adhesive will not flow and close the grooves and adhere to the liquid ejection force generating element, causing functional deterioration.

8. The detailed formation of the main components of an inkjet head is performed by photolithography, and since this photolithography is generally performed in a clean room used in the semiconductor industry, it is difficult to form inside the ink path during the assembly of the inkjet head. It is possible to minimize the intrusion of dirt.

[Brief explanation of the drawing]

1 to 7(b) are schematic diagrams for explaining the structure of the liquid jet recording head of the present invention and its manufacturing procedure, and FIG. 1 is a schematic diagram for explaining the first step. FIG. 2(a) is a schematic perspective view for explaining the second step, FIG. 2(b) is a partial cross-sectional view taken along the dashed line XX' shown in FIG. 2(a), FIG. 3 is a schematic perspective view for explaining the third step, FIG. 4 is a schematic perspective view for explaining the fourth step,
5 is a schematic perspective view for explaining the fifth step, FIG. 6 is a schematic perspective view for explaining the sixth step, FIG. 7(a) is a schematic perspective view showing the structure of the completed head, Figure (b) is similar to Figure 7 (a).
) is a cross-sectional view taken at a position indicated by a dashed line YY'. 1...Substrate 2...Heating element applicant Canon Corporation

Claims (1)

[Scope of Claims] A liquid flow path which has an ejection port for ejecting the liquid to form flying droplets at the end of the liquid flow direction and is bent in the middle; forming at least a part of the flow path;
The liquid flow path has a heat acting part where the liquid filling the interior undergoes a thermal action and causes a state change, and a heating element that generates heat to be transferred to the liquid filling the heat acting part. A liquid jet recording head 0 characterized in that the main part of the wall surface is formed by curing a photosensitive resin.