KR100536088B1 - Inkjet head membrane consisting of multi-layer thin film of polyimide and metal - Google Patents

Abstract

The present invention is to provide a membrane of an inkjet printer head that can improve the ejection performance of the inkjet printer by excellent adhesion, durability and mechanical properties, and a liquid that heats the heater by electrical energy and thermally expands by the heat In the inkjet printer head of the method of flowing a membrane and spraying ink to the media according to the flow of the membrane, the membrane is 0.1 ㎛ to 1.5 ㎛ thick polyimide on both sides of the 0.1 ㎛ to 1.5 ㎛ thick metal film It relates to a membrane of the inkjet printer head, characterized in that the multi-layer thin film prepared by coating. Since the membrane of the inkjet printer head according to the present invention has excellent adhesion, durability, and mechanical properties, it is possible to improve the performance of the inkjet printer head by using the membrane produced by the present invention.

Description

Inkjet printer membrane consisting of multi-layer thin film of polyimide and metal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane of an inkjet printer head made of a polyimide and a metal thin film. Specifically, the membrane is heated using a liquid and a gas that heats the heater by electrical energy and thermally expands by the heat, In an inkjet printer head in which ink is injected into a media according to flow, a multilayer thin film prepared by coating a membrane of a print head with a polyimide having a thickness of 0.1 μm to 1.5 μm on both sides of a metal thin film having a thickness of 0.1 μm to 1.5 μm. It relates to a membrane of the inkjet printer head, characterized in that.

The inkjet printer system uses a bubble jet method (Canon Corporation) that heats a liquid ink with a heating element in the inkjet head and generates bubbles to inject ink, and uses a piezo element whose shape is changed by voltage. Machjet method (Epson), and thermal transfer method (Hewlett-Packard company) in which a part of the nozzle is deformed by heating the heater and ink is dispersed, and ink is discharged by heating a working fluid such as heptane. It can be divided into thermal compression method. Among them, the thermal compression method sprays ink according to the deformation of the membrane by controlling thermal expansion of liquids and gases in the heating chamber without being sprayed by the vapor pressure of the bubble, so that the ink and the heater may be separated, thereby causing corrosion due to contact with the ink. It is possible to prevent the damage, the protective film is prevented from being damaged by the impact generated when the bubble is generated and injected into the opening, there is an advantage that the high-speed output is possible because the refilling of the ink is made faster.

Since the thermal compression inkjet printer head drives the membrane at a pressure caused by the heating of a liquid or gas in the heating chamber, the membrane used requires excellent mechanical properties and durability.

Conventionally, metal or polyimide was generally used as the material of the membrane. However, when the membrane is made of a metal such as nickel (Ni), it is difficult to bond the support with the polyimide, and the oxidation of the metal and the mutual reaction with the ink are difficult. In order to prevent the need for gold (Au) coating has a problem that the process is complicated and the manufacturing cost increases. In addition, the use of polyimide as the material of the membrane has the advantage of less chemical interaction with the ink and there is no risk of corrosion due to oxidation compared to the metal, but when the durability is insufficient and the design of the head structure to about 300dpi is large Figure 1 There is a disadvantage in that the asymmetric wave is developed as shown in (b) and eventually, when the film forms an irregular wave, bubbles are generated inside the film, and the performance of the film is greatly reduced, causing problems when ejecting ink.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a membrane of an inkjet printer head which can improve the ejection performance of an inkjet printer by providing excellent adhesion, durability and mechanical properties.

The above object can be achieved by providing a new membrane which can compensate for the difficulty and cost of the metal thin film manufacturing process, the risk of oxidation and corrosion of the metal thin film, and the lack of durability of the polyimide.

The present invention relates to an inkjet printer head in which a membrane is flowed by using a liquid and gas that heats a heater by electrical energy and thermally expands by the heat, and injects ink into the media according to the flow of the membrane, wherein the membrane of the printer head is used. It is characterized in that it is a multilayer thin film prepared by coating a polyimide having a thickness of 0.1 μm to 1.5 μm on both surfaces of the metal thin film of 0.1 μm to 1.5 μm thickness.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 illustrates a structure of a conventional thermal compression inkjet printer head, in which an aluminum layer 80 is disposed on a silicon wafer layer 70 and a heat generating unit 10 is disposed inside the aluminum layer. When heated, the liquid or gas in the heating chamber 20 is thermally expanded by the heat to flow the upper membrane 40 fixed by the support 30, and the ink 50 moves to the nozzle 60 according to the flow of the membrane. It is sprayed through. It is a feature of the present invention to improve the membrane used in this type of printer head, Figure 3 shows a membrane cross-sectional structure of the inkjet printer head according to the present invention, a metal thin film of 0.1㎛ to 1.5㎛ thickness ( 41, the multilayer thin film of the metal and polyimide by which the polyimide resin film 42 of 0.1 micrometer-1.5 micrometer thickness was coat | covered on both upper and lower sides is shown.

In the present invention, the metal thin film 41 is prepared by evaporation, sputtering, or plating a transition metal such as copper, aluminum, titanium, or nickel, and these methods are generally used in the art when manufacturing a metal thin film. The method to be used is not particularly limited in the present invention.

In the present invention, the polyimide resin film 42 is formed by spin coating, roller coating, immersion coating, spray coating, or the like on a polyamic acid solution obtained by reacting a diamine containing an amine or siloxane bond with a tetracarboxylic dianhydride under an organic solvent. After coating on the metal thin film 41 by the method of manufacturing by imidization (Imidization) through a heat treatment process.

The polyamic acid solution used in the present invention is generally obtained by forming a monoamic acid by reaction of tetracarboxylic dianhydride and diamine in a suitable organic solvent, followed by condensation reaction of the monoamic acid. The resulting polyamic acid is represented by the formula (1).

Wherein Q is one or more of the following:

In addition, R is 1 or more types chosen from the following.

However, in the substituent containing a siloxane bond, m is an integer of 1-10, n is an integer of 1-5.

In synthesizing the polyamic acid, Q and R in the dianhydride and diamine are substituted with one of the substituents described above to induce a reaction, and the durability of the polyimide resin film finally obtained according to each substituent is improved or There is a characteristic that can improve adhesion. In particular, when R is a substituent containing a siloxane bond shown in the above scheme, it is useful for improving adhesion to the support. Substituents containing such siloxane bonds may occupy 0 to 20% by weight of the total diamine component added during the reaction, but exceeding 20% by weight may adversely affect the mechanical properties of the membrane, which is not preferable.

The organic solvent used in the polyamic acid polymerization in the present invention may be NMP (1-methyl-2-pyrrolidinone), DMAc (dimethyl acetamide), DMF (dimethyl formamide), etc., these three solvents are polyamic acid During polymerization, it catalyzes the polymerization reaction and promotes imidization in the subsequent imidization process.

In the present invention, since the reaction ratio of the dianhydride and diamine to be reacted during the polyamic acid polymerization is 1: 1, the two monomers are reacted in the same molar ratio, and the dianhydride and diamine monomers are combined in an amount of 1 to 50 based on 100 parts by weight of the organic solvent. In the polyamic acid solution obtained by reacting the parts by weight, 1 to 50 parts by weight of the polyamic acid solid is dissolved in 100 parts by weight of the organic solvent. When the concentration of the polyamic acid is less than 1 part by weight, it is difficult to achieve the effect to be achieved in the present invention. When the concentration of the polyamic acid is more than 50 parts by weight, the viscosity of the polyamic acid solution becomes too high, making coating difficult.

When the polyamic acid solution prepared as described above is coated on the surface of the silicon wafer or the metal thin film by spin coating, roller coating, immersion coating, spray coating, or the like, and the coated film is cured at high temperature (imidization), dehydration occurs. Polyimide resin film is manufactured. During the imidization process, a change such as the following Scheme 1 occurs.

In the present invention, the curing conditions are dried at 100 to 120 ℃ using a heating plate or an oven (3 to 30 minutes in a heating plate, 10 to 60 minutes in an oven), gradually heated up in an oven under a nitrogen atmosphere temperature range of 320 to 400 ℃ It is preferable to heat for 1-2 hours at.

In the production of the membrane multilayer thin film in the present invention, by coating a polyimide resin film as described above and depositing a metal thin film on the surface by a method such as vapor deposition, sputtering, plating, etc., the polyimide resin film is coated on the surface of the metal thin film again. Is done. The metal thin film and the polyimide resin film on both sides thereof are formed to have a thickness of 0.1 to 1.5 탆, respectively. However, when each thickness is less than 0.1 탆, durability is deteriorated. This becomes poor, making it difficult to use as a print head. Most preferably, manufacturing the membrane so that the thickness is formed in the vicinity of 3 μm may satisfy both durability and driveability.

The membrane prepared by the present invention is attached by applying physical pressure to a support made of a metal or a heat resistant polymer resin at a temperature of 300 ℃ to 400 ℃. In particular, in the case where the type of the support to be attached to the membrane is polyimide, the adhesion with the membrane according to the present invention becomes better.

Hereinafter, the present invention will be described in detail by way of examples. In this embodiment, a heat chamber was manufactured by modeling a thermocompression inkjet printer head in order to evaluate the superiority of the membrane. However, the driving method was heated on a hot plate unlike the heating part of the actual thermoelectric inkjet printer head. Instead of expanding the membrane and then cooling and shrinking.

The following examples are intended to illustrate the invention and are not intended to limit the claims of the invention.

Example 1

Iii) Preparation of polyamic acid solution

283.26 g of NMP (1-methyl-2-pyrrolidinone) and 19.00 g of TPE-Q (4,4'-Diaminodiphenylether) were added to a 500 ml reactor, and the mixture was stirred at 25 ° C. for 10 minutes. 20.16 g of ODPA (4,4'-Oxydiphthalic dianhydride) was added to the powder state, stirred for 3 hours, heated at 80 ° C for 2 hours to synthesize a polyamic acid solution, and permeated through a 1.2 μm filter paper to obtain a viscosity of 1700 cps. A polyamic acid solution was prepared.

Ii) Multi-layer thin film manufacturing

Put the silicon wafer on the spin coat and coat the polyamic acid solution prepared in step iii), dry it for 10 minutes on a 100 ° C hot plate, put it in an oven and slowly raise the temperature to cure at 360 ° C for 30 minutes to make a polyimide layer. The film was prepared so that the thickness was 1 탆. The copper was deposited on the prepared polyimide resin film at a thickness of 1 μm, and the coating was again carried out on a spin coat to coat the same polyamic acid solution on a copper thin film, dried over a heating plate of 100 ° C. for 10 minutes, and then slowly heated in a oven at 360 ° C. Curing for 1 hour to prepare a polyimide resin film so that the polyimide layer thickness is 1㎛. The multilayer thin film could be separated from the silicon wafer by placing it in an HF solution and taking it out or leaving it in a high pressure vessel at a relative humidity of 100% and 120 ° C for about 3 hours.

Iii) Preparation of evaluation samples

Put the silicon wafer 90 on the spin coat and coat the polyamic acid solution prepared in step iii), dry it for 10 minutes on a 100 ° C heating plate, and slowly raise the temperature in the oven to cure at 360 ° C for 30 minutes to thicken the polyimide layer. The film | membrane was manufactured so that it might become 5 micrometers. The polyimide resin film was dry etched using oxygen plasma to form a fine pattern 100 as shown in FIG. This fine pattern and its cross-sectional shape are shown in Fig. 4 (b). The multilayer thin film prepared in step ii) was placed on the fine pattern and heated in a 360 ° C. oven for 2 hours to fuse the multilayer thin film to the fine pattern. The heptane inlet 110 having a diameter of 50 μm is formed on the multilayer thin film fused to the micropattern as shown in FIG. 5. The polyimide layer is peeled off with oxygen plasma, and the metal layer is peeled off with a developer made by mixing sulfuric acid, hydrogen peroxide, and water. It is made by stripping off the remaining polyimide layer with oxygen plasma. This was put into a sealed container and heptane was mixed into the container while vacuum was applied to fill the empty space between the multilayer thin film and the silicon wafer with heptane. The heptane inlet was then sealed with an epoxy strong adhesive to complete the evaluation sample.

평가) Evaluation

The evaluation sample prepared by the above method is placed on a heating plate at 200 ° C to 250 ° C for 5 seconds and then cooled to room temperature. After raising the cooled evaluation sample to the heating plate again for 5 seconds, and cooling 30 times, the height difference of the surface of the multilayer thin film was measured and bubbles were generated. The results are shown in Table 1 below.

Comparative Example 1

Iii) Preparation of polyimide resin film

450.905 g of NMP (1-methyl-2-pyrrolidinone) and 15.080 g of ODA (4,4'-Diaminodiphenylether) were added to a 1 L reactor, and the mixture was stirred for 10 minutes at 25 ° C under a nitrogen atmosphere. 16.432 g of PMDA (1,2,4,5-Benzenetetracarboxilic Pyromellitic dianhydride) was added thereto in a powder state, stirred for 3 hours, heated at 80 ° C. for 2 hours to synthesize a polyamic acid solution, and then permeated 0.45 μm filter paper. A polyamic acid solution having a viscosity of 2000 cps was prepared. The silicon wafer was placed on the spin coat, coated with a polyamic acid solution, dried on a 100 ° C. heating plate for 10 minutes, and placed in an oven to cure at 360 ° C. for 30 minutes while gradually raising the temperature to prepare a film having a thickness of 1.5 μm. It was. On the polyimide resin film thus prepared, the polyamic acid solution was coated in the same manner as in Example ⅰ), dried on a heating plate at 100 ° C., and placed in an oven to cure at 360 ° C. for 1 hour while gradually raising the temperature. A polyimide resin film was prepared such that the thickness of the first polyimide layer was 1.5 μm. The polyimide resin film was separated from the silicon wafer by placing it in an HF solution and taking it out or by leaving it in a high pressure vessel at a relative humidity of 100% and 120 ° C for about 3 hours.

Ii) preparation of comparative samples

In the same manner as in Example (iii), a fine pattern of polyimide resin was prepared, and the polyimide resin film prepared in (iii) of Comparative Example was fused onto the fine pattern. And as in Example iii) heptane inlet was made to fill the heptane and sealed with an adhesive to complete the comparative sample.

평가) Evaluation

The height difference of the surface of the polyimide resin film was measured in the same manner as in Example iii), and the presence of bubbles was confirmed. The results are shown in Table 1 together.

▶ Evaluation Method ◀

Height difference of film surface

As shown in FIG. 6, the durability of the membrane was determined by measuring a step in which the membrane drooped down after driving the membrane.

Bubble presence

The suitability of the thermoelectric inkjet head as a membrane was judged by observing whether bubbles were generated by driving the membrane.

Example 1 Comparative Example 1 Step 0.2 1.8 Bubble occurrence × ○

The membrane of the inkjet printer head according to the present invention is excellent in adhesion, durability and suitability as a membrane, and thus, the membrane produced by the present invention can be used to improve the performance of the inkjet printer head.

1 is a wave pattern of a membrane (a) regular wave (b) irregular wave,

2 is a schematic view of a typical heat compression inkjet printer head,

3 is a cross-sectional view of a membrane according to the present invention,

4 is a schematic diagram of a fine pattern of a polyimide resin film of an evaluation sample;

5 is a schematic diagram of a fine pattern punched through the heptane inlet;

6 shows a step of the membrane.

Explanation of symbols for the main parts of the drawings

DESCRIPTION OF SYMBOLS 10 Heating part 20 Heating chamber 30 Support body 40 Membrane

41 metal thin film 42 polyimide resin film 50 ink

60: nozzle 70: silicon wafer layer 80: aluminum layer

90 silicon wafer 100 fine pattern of polyimide resin film

Claims (5)

A thermal compression inkjet printer head, wherein the membrane of a printer head is a multilayer thin film manufactured by coating a polyimide resin film having a thickness of 0.1 μm to 1.5 μm on both sides of a metal film having a thickness of 0.1 μm to 1.5 μm, The membrane of the inkjet printer head, wherein the polyimide resin film is made of a polyimide compound having the following structure prepared by imidizing a polyamic acid solution. Provided that Q is one or more selected from R is at least one selected from the following. However, in the substituent containing the said siloxane bond, m is one of the integers of 1-10, and n is one of the integers of 1-5. The membrane of claim 1, wherein the metal thin film is selected from the group consisting of copper, aluminum, titanium, and nickel. delete The membrane of an ink jet printer head according to claim 1, wherein the polyamic acid solution is dissolved in an amount of 1 to 50 parts by weight of the polyamic acid having the following structure with respect to 100 parts by weight of the solvent. Provided that Q is one or more selected from R is at least one selected from the following. However, in said substituent containing a siloxane bond, m is one of the integers of 1-10, and n is one of the integers of 1-5. 5. The membrane of an inkjet printer head according to claim 1 or 4, wherein the diamine substituted with the substituent containing a siloxane bond comprises 0 to 20% by weight of the total diamine component added during the polyamic acid polymerization.