JPH07148930A - Ink jet head and production thereof - Google Patents

Abstract

PURPOSE:To provide an ink jet head having an ink repelling layer whose ink repelling capacity is not lowered and always uniform with respect to repeated cleaning operation aiming at the removal of the foreign matter such as an ink droplet or a paper powder bonded to the ink repealling layer on a nozzle plate. CONSTITUTION:In an ink jet head having a pressure chamber and a piezoelectric element or heating element being a means applying pressure to the ink charged in the pressure chamber and emitting the ink pressurized in the pressure chamber from the nozzle orifices 2 formed to the surface 1 of a nozzle plate, a polymerized cured film of an epoxy resin consisting of a main agent and a fluorine compd. having at least one reactive group selected from an opoxy group, an amino group, a hydroxyl group, an acid anhydrile group and a carboxylic acid group in its molecular chain is formed to the surface 1 of the nozzle plate to form an ink repelling layer 3.

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 used in an ink jet recording apparatus.

[0002]

2. Description of the Related Art A printer using an ink jet head for forming an image on a recording paper by ejecting ink droplets from a nozzle hole has been put into practical use with the features of quietness and high density printing. The print quality of an image obtained by such an ink jet head largely depends on the positional accuracy of the dots that form the image and are formed of ink droplets on the recording paper. The dot position accuracy depends on whether or not the flight direction of ink droplets ejected from the nozzle holes of the inkjet head is constant. Furthermore, a factor that keeps the flight direction of the ink droplets constant is that the peripheral edge of the nozzle hole is a uniform and stable surface state when the ink droplet is ejected, and specifically, a part of the peripheral edge of the nozzle is wet with ink. Or, to realize a surface condition of the peripheral portion of the nozzle in which a situation such as the adhesion of foreign matter such as paper powder does not occur. In the prior art, the following two methods have been proposed as means for making the surface condition of the peripheral portion of the nozzle uniform and stable. First, an ink repellent treatment is applied to the surface of the nozzle plate including the peripheral portion of the nozzle hole. Secondly, when ink adheres to the peripheral edge of the nozzle hole that has been subjected to the ink repellent treatment, or when foreign matter such as paper dust adheres, the nozzle plate surface including the peripheral edge of the nozzle is made of a rubber blade or the like cleaning member. There are two ways to scrape. As a means for improving the image quality on the recording paper in this way, the following specific proposals have been made.

First, the ink jet head disclosed in Japanese Patent Laid-Open No. 62-202743 will be described with reference to FIG. 4 as an example of the first prior art. The ink repellent member 10, which is a means for preventing ink from adhering to the peripheral edge of the nozzle hole, is made of a surfactant-type fluorine-based polymer, and is provided between the ink repellent member 10 and the metal nozzle 9 in order to obtain adhesion between them. Is provided with a resin layer 11. The resin layer 11 that indirectly improves the adhesiveness between the metal nozzle 9 and the ink repellent member 10 includes an epoxy resin, a polyamide resin, a polyurethane resin, a phenol / epoxy resin, a phenol / polyamide as a resin having good adhesiveness to the metal. Uses resin. That is, for the metal nozzle 9, the ink repellent member 1
Since there is no adhesiveness of the fluoropolymer which is a surfactant type constituting 0, the resin layer 1 serves as a so-called binder.
1 is provided. The adhesiveness between the resin layer 11 made of an epoxy resin or the like and the surfactant type fluoropolymer can be stronger than the adhesiveness between the metal nozzle 9 and the fluoropolymer, but it is not sufficient. because,
As described above, in order to obtain a high-quality image, it is necessary to completely avoid wetting with ink and adhesion of foreign matter such as paper dust when ejecting ink droplets on the peripheral portion of the nozzle hole. Even if the peripheral edge of the nozzle is in an ideal surface state in terms of surface tension, it is difficult to prevent wetting of the peripheral edge of the nozzle by ink due to sudden ink ejection failure or adhesion of paper dust generated from recording paper. Is. Therefore, a means for scraping off the surface of the nozzle plate including the peripheral portion of the nozzle hole with a cleaner member such as a rubber blade is indispensable. It cannot be said that the adhesion between the ink repellent member 10 and the resin layer 11 against the scraping operation by the cleaner member, especially the repeated operation is sufficient. The lack of the ink repellent member 10 from the resin layer 11 due to the cleaning operation causes a partial unevenness of the ink repellent performance on the surface of the ink repellent member, and the ink is easily wetted at the portion where the ink repellent performance is deteriorated. At a remarkable time, the ink always adheres to the portion where the ink repellency is deteriorated, the flight direction of the ink is not fixed, and the image quality on the recording paper is deteriorated.

On the other hand, the prior art shown in FIG. 5 proposed for the purpose of improving the durability of the ink repellent member against the cleaning operation of the surface of the nozzle plate is disclosed in JP-A-3-53942. As illustrated in FIG. 5, the partition wall 13 having a predetermined pattern is formed on the substrate 12, and the substrate 17 is mounted via the partition wall 13. Orifice 14 and ink tank 15 by partition wall 13
And a heating element 16 as a pressure generating means is arranged on the surface of the substrate 12 in the orifice 14. A surface treatment layer having good ink repellency is formed on the ink ejection surface formed by the substrate 12, the substrate 17, and the partition wall 13, that is, the peripheral edge portion of the orifice. This ink-repellent treatment layer is a solvent-soluble fluoropolymer having two or more acryloyl groups in the molecule and an average molecular weight of 2000 or more,
Formed by polymerizing and curing a composition having one or more reactive groups selected from the group consisting of a fluoroalkyl group, a fluoroallyl group, a fluorocycloalkyl group, a fluoroalkaryl group, and a fluoroalkylallyl group and a silazane group. . As described above, the ink-repellent treatment layer is provided with a reactive group in the fluorine compound that is responsible for the ink-repellent performance, so as to improve the abrasion resistance at the time of cleaning the peripheral portion of the orifice, that is, to maintain the ink-repellent performance. It is a thing. However, the fluoropolymer is poor in rigidity and does not always exhibit sufficient ink repellency in the cleaning operation of the nozzle plate or the orifice surface using a rubber blade. The reason for this is that although there is no omission due to the cleaning operation of the fluoropolymer, changes in the minute undulations on the surface of the treatment layer formed by the molecular chain mass of each fluoropolymer are observed. Alternatively, repeated cleaning operations may cause minute scratches on the surface of the treatment layer. Due to such reasons,
The repelling property of the ink on the surface of the ink repellent treatment layer is obviously deteriorated.

[0005]

In order to keep the quality of an image formed on a recording paper by ink droplets ejected from an ink jet head always in good condition, an ink called a nozzle hole or an orifice of the ink jet head is used. It is an essential condition that the flight direction of the ink droplet ejected from the droplet ejection port is constant. In order to make the flight direction of the ink droplet constant, there are two conditions as described above. At the time of ink ejection, the peripheral edge of the nozzle hole is in a surface state in which the ink is hard to wet, and the ink repellency performance is uniform at any position on the peripheral edge of the nozzle. A means for removing foreign matter such as ink or paper powder adhering to the peripheral portion of the nozzle hole, that is, sufficient ink repellency at the peripheral portion of the nozzle hole even after repeated cleaning operations with a rubber blade, etc. That is, the ink repellent performance is uniform in the peripheral portion.

As described in the above examples of the prior art, in any case, if the peripheral edge of the nozzle hole or the nozzle plate surface including the peripheral edge of the nozzle hole is subjected to a cleaning operation, the ink repellent performance of the ink repellent treatment layer is improved. There is a problem that the ink repellency is lowered or the ink repellency is not uniform in the peripheral portion of the nozzle hole. Therefore, as long as this problem exists, it is difficult to guarantee the print quality and the image quality for a long period of time.

The present invention has been made to solve the above-mentioned conventional problems, and the purpose thereof is to provide an ink-repellent treated layer,
It prevents deterioration and non-uniformity of ink repellency due to the cleaning operation, and thus keeps the flight direction of ink droplets from the nozzle holes constant, so that the quality of images and prints formed on recording paper can be maintained for a long period of time. To secure it.

[0008]

An ink jet head of the present invention comprises means for applying pressure to ink filled in a pressure chamber, and nozzles formed with ink pressurized in the pressure chamber on a nozzle plate surface. It is an inkjet head for discharging from a hole. The present invention, in such an inkjet head, has an epoxy resin composed of a main agent and a curing agent on the nozzle plate surface, and at least one of an epoxy group, an amine, a hydroxyl group, an acid anhydride, and a carboxylic acid reactive group in the molecular chain. The ink-repellent layer is characterized by forming a polymerized and cured film with a fluorine compound having a reactive group.

[0009]

The ink jet head of the present invention comprises an epoxy resin composed of a main agent and a curing agent, and an epoxy group, an amine, a hydroxyl group, an acid anhydride, a carboxylic acid in the molecular chain on the surface of the nozzle plate which is the ejection surface of ink droplets. To form a polymerized and cured film with a fluorine compound having any of the above. The polymerized and cured film of the epoxy resin and the fluorine compound has excellent bonding strength with the nozzle plate and excellent rigidity, so that the ink repellent performance is not deteriorated even after repeated cleaning operations, and the nozzle plate having the ink repellent performance is also excellent. Since non-uniformity does not occur on the surface, a high quality and stable image can be obtained.

[0010]

【Example】

(Embodiment 1) FIG. 1 shows an epoxy resin composed of a main agent and a curing agent, an epoxy group, an amine, a hydroxyl group, an acid anhydride in the molecular chain, on the surface of a nozzle plate in which nozzle holes are arranged.
FIG. 3 is a cross-sectional view of a nozzle hole and a vicinity of the nozzle hole of the present invention in which a polymerized and cured film of a fluorine compound having at least one reactive group among the reactive groups of carboxylic acid is installed. 80μm thick nozzle plate 1 made of stainless steel
A nozzle hole 2 having a hole diameter of 30 μm on the ink droplet ejection side was formed by a pressing method, and an ink repellent layer 3 made of a polymerized and cured film of an epoxy resin and a fluorine compound was formed on the ink droplet ejection surface. Catalyst 1 containing the ink repellent layer 3 as the main component of the epoxy resin, XNR3305 (Nippon Ciba Geigy), and the main component of the modified aromatic amine as the curing agent.
1 (Grace Japan Co., Ltd.), and each of 3- (perfluoro-9-methyldecyl) -1,2-epoxypropane was used as a fluorine compound having an epoxy group in the molecular chain. The specific compounding ratio of these is the epoxy resin main agent:
Epoxy resin curing agent: fluorine compound = 20: 3: 10 weight ratio. The amine contained in the curing agent reacts with the epoxy group contained in the epoxy resin as the main component and the epoxy group contained in the fluorine compound to form a polymer. This polymer has the inherent rigidity of a cured epoxy resin and, at the same time, has excellent properties in terms of binding force with stainless steel, which is the material of the nozzle plate. Further, the ink repellent performance shows excellent ink repellent performance, and further shows excellent properties as compared with general fluororesins such as polytetrafluoroethylene. The above-mentioned 3- (perfluoro-9) is added to the fluorine compound.
-Methyldecyl) -1,2-epoxypropane has a critical surface tension of 18 for polytetrafluoroethylene.
It was 12 dyn / cm as opposed to dyn / cm. The critical surface tension of the ink repellent layer was experimentally determined from the relationship between the surface tension of the organic solvent and the contact angle using several kinds of organic solvents such as organic ester and hydrocarbon.

The 3- (perfluoro-9) thus obtained
The durability of the ink repellent layer 3 using -methyldecyl) -1,2-epoxypropane to the cleaning operation was investigated. First, as a cleaning means, chloroprene rubber having a hardness of 50 degrees was adopted for the rubber blade. For the cleaning operation, two methods were used: wiping the surface of the ink repellent layer with a rubber blade, or dropping 1 cc / cm ² of ink drops on the surface of the ink repellent layer every 10 times of cleaning. Two types of ink were used: an aqueous dye-dissolving type and an aqueous pigment-resin dispersing type. The content ratio of the pigment and the resin, which are solid contents, is 15%. In the cleaning test, the background of setting the condition of dropping ink drops on the surface of the ink repellent layer and the condition of not dropping the ink drops is because two extreme situations can be assumed when the cleaning operation is performed during actual use. is there. That is, the cleaning operation for the purpose of removing foreign matter such as paper dust attached to the surface of the nozzle plate is in a dry wiping state and is not in a normal ink ejection state, for example, nozzles due to ink scattering due to bubbles accumulated in the nozzle holes. If the plate surface becomes contaminated, this means a cleaning operation with the nozzle plate surface wet with ink. The cleaning operation was repeated up to 5000 times by rubbing the surface of the ink repellent layer in the same direction with a rubber blade. In order to investigate whether or not the ink repellency was deteriorated, the initial value of the contact angle of the ink drop on the ink repellent layer surface and the transition of the contact angle of the ink drop after every 50 cleanings were observed. The contact angle was measured in the following directions:
That is, the direction is perpendicular to the cleaning direction so that the generation of minute scratches, the orientation of the resin, and the like can be detected.

The results of the cleaning test are shown in FIGS. 2 (a), 2 (b) and 2 (c). FIG. 2A shows the transition of the contact angle of the ink when the surface of the ink repellent layer is wiped with a rubber blade. The ink used for measuring the contact angle is a type of ink having a surface tension of 35 dyn / cm and in which a pigment and a resin are dispersed. (B) is (c) when a dye-dissolving type having a surface tension of 55 dyn / cm is used for the ink,
Shows the results obtained by using a dispersion type of a pigment and a resin in an ink having a surface tension of 35 dyn / cm.

As can be seen from FIG. 2, the ink repellent layer of the present invention shows almost no deterioration in the ink repellent performance even after 5000 cleaning operations, regardless of the test results. What this experimental result means is that, as can be seen from (a) and (c), no matter what state the ink-repellent layer surface is in during the cleaning operation,
The non-uniformity of the ink repellent performance on the surface of the ink repellent layer due to the repeated cleaning does not occur. Secondly, as can be seen from (b) and (c), it can be concluded that the ink repellent layer of the present invention has sufficient rubbing properties even for an ink containing a solid content in which a pigment and a resin are dispersed. . In the case of the polytetrafluoroethylene mentioned above, there is a large difference in the durability of the ink repellency due to the cleaning operation between the dye ink containing no solid content and the pigment ink containing solid content. In the cleaning test in which the pigment ink was dropped on the surface of the ink repellent layer, a marked decrease in the ink repellent performance of polytetrafluoroethylene and nonuniformity were observed.

Further, the nozzle plate of the present embodiment that has been subjected to a cleaning test 5000 times and the nozzle plate of the present embodiment that has not been subjected to the cleaning test are used.
The image was output by mounting it on an actual inkjet head and recording paper, and examined whether there was a difference in image quality. As a result, both were able to obtain good image quality and there was no difference between them, and it was confirmed that the ink repellent layer of this example has sufficient cleaning resistance.

Next, a method for manufacturing the ink repellent layer of this embodiment will be described. FIG. 3 shows a process up to forming the ink repellent layer 3 on the nozzle plate 1 having the nozzle holes 2. (A) is a nozzle plate 1 made of stainless steel having a thickness of 80 μm, in which a plurality of nozzle holes 2 having ejection ports of 30 μm are arranged on the ejection surface 4 side of ink droplets.
On the pressure chamber (not shown) side 5 of the nozzle plate of (a),
(B) is a diagram in which the positive resist 6 is applied by a roll coater. As the resist 6, BMR (Tokyo Ohka Co., Ltd.) was used. The coating thickness was 5 μm, and the drying condition after coating was 80 ° C. and 10 minutes. By this step, the inside of the nozzle hole 2 is completely covered, and the inside of the nozzle hole 2 is prevented from being subjected to ink repellent treatment. (C) is a diagram in which BMR is applied and dried on the ejection surface 4 of the ink droplets in the same manner as in (b). The coating thickness was also 5 μm. After that, ultraviolet rays are irradiated from the direction of the pressure chamber side 5 of the nozzle plate for exposure. Further Na
When developed with an OH 5% aqueous solution, the nozzle plate 1 plays a role of a mask, and the resist pattern shape shown in (d) is obtained. The developing conditions were to immerse the above alkaline aqueous solution for 20 minutes at room temperature. Next, the proper ink ejection surface 4
In addition, 20 parts of epoxy resin main agent XNR3305, 3 parts of epoxy resin curing agent catalyst 11 and 10 parts of fluorine compound 3- (perfluoro-9-methyldecyl) -1,2-epoxypropane having an epoxy group in the molecular chain are kneaded. The liquid mixed resin 8 is applied by a roll coater.
The thickness of the liquid mixed resin 8 was 3 μm or less. In this step, since the resist convex portion 7 of the ink ejection surface 4 has rubber elasticity, it does not drop off during coating with a roll coater. After applying the liquid mixed resin 8, it is placed in an environment of 100 ° C. for 2 hours. Under this environment, the amine contained in the epoxy resin curing agent reacts and polymerizes with the epoxy resin base and the epoxy groups contained in the fluorine compound, and the liquid mixed resin 8 becomes a polymerized and cured film. Finally, when immersed in a 60 ° C. BMR stripping solution (Tokyo Ohka Co., Ltd.) for 30 minutes, the resist drops off from the nozzle plate, and the nozzle plate having the ink repellent layer made of the polymerized and cured film of this example shown in (f) is formed. can get.

Example 2 In Example 2, 1H. 1H heptafluorobutylamine was used. The epoxy resin main component is the same as in Example 1. Catalyst 9 (Grace Japan) as a curing agent
It was adopted. The compounding ratio of these is a weight ratio, epoxy resin main agent: epoxy resin curing agent: fluorine compound = 10: 1:
It is 5. The manufacturing process for forming the ink repellent layer is the same as in Example 1, except that 1H. Since the boiling point of 1H heptafluorobutylamine is 75 ° C., the curing condition was room temperature for 24 hours. The curing agent Catalyst 9 is a resin that can undergo a curing reaction at room temperature. Catalyst 9 and 1H. The amine contained in 1H heptafluorobutylamine reacts with the epoxy group contained in the epoxy resin base material to form a polymerized and cured film.

Using the ink jet head having the ink-repellent layer formed of the polymerized and cured film produced as described above, the ink-repellent layer cleaning durability test and the actual printing test were conducted in the same manner as in Example 1. The adhesion to the nozzle plate and the hardness of the ink repellent layer surface were good, and a high quality image was obtained.

(Example 3) In Example 3, 2- (perfluorodecyl) ethanol and 2- (perfluoro-9-methyldecyl) ethanol having a hydroxyl group in the molecular chain of a fluorine compound were used. The epoxy resin main agent and the curing agent are the same as in Example 1. The compounding ratios are all weight ratios, and the epoxy resin main agent: epoxy resin curing agent: fluorine compound =
It is 20: 3: 10. The manufacturing process for forming the ink repellent layer is the same as in the first embodiment. 2- (perfluorodecyl)
The hydroxyl groups contained in the molecular chains of ethanol and 2- (perfluoro-9-methyldecyl) ethanol react with the epoxy groups contained in the epoxy resin base material, and the amine contained in the curing agent is also contained in the epoxy resin base material. Reacts with epoxy groups. Thus, the three form a polymer in which the epoxy resin is bonded to the medium to form a polymer.

The results of the cleaning durability test and the actual printing test are the same as in Examples 1 and 2, and the adhesion to the nozzle plate and the hardness of the ink repellent layer surface are good, and a high quality image is obtained. Was given.

(Example 4) In Example 4, 2.2 bis (3.4 anhydrodicarboxyphenyl) hexafluoropropane having acid anhydride in the molecular chain of the fluorine compound was used. The epoxy resin main agent and the curing agent are the same as in Example 1. The compounding ratio is a weight ratio, and is epoxy resin main agent: epoxy resin curing agent: fluorine compound = 20: 3: 7.
The manufacturing process for forming the ink repellent layer was the same as in Example 1, but the curing conditions for obtaining the polymerized and cured film were 160 ° C. and 2 hours. This is because it takes a high temperature for the carboxylic acid anhydride contained in 2.2 bis (3.4 anhydrodicarboxyphenyl) hexafluoropropane to react with the epoxy group contained in the epoxy resin base. 2.2 The carboxylic acid anhydride contained in bis (3.4 anhydrodicarboxyphenyl) hexafluoropropane reacts with the epoxy group contained in the epoxy resin base material, and the epoxy group contained in the epoxy resin base material simultaneously cures. Reacts with amines therein to form polymers.

The results of the cleaning durability test and the actual printing test are the same as in Examples 1 and 2, and the adhesion to the nozzle plate and the hardness of the ink repellent layer surface are good, and a high quality image is obtained. Was given.

Example 5 In Example 5, perfluorodecanoic acid and perfluoroundecanoic acid having a carboxylic acid in the molecular chain of a fluorine compound were used. The epoxy resin main agent and the curing agent are the same as in Example 1. The compounding ratio is a weight ratio, that is, epoxy resin main agent: epoxy resin curing agent: fluorine compound = 20: 3: 10. The manufacturing process for forming the ink repellent layer was the same as in Example 1, but the curing conditions for obtaining the polymerized and cured film were 160 ° C. and 2 hours. Carboxylic acid contained in perfluorodecanoic acid and perfluoroundecanoic acid, and the amine contained in the curing agent react, the epoxy group contained in the epoxy resin main agent reacts with the amine in the curing agent, Form a polymer.

An ink jet head having the ink-repellent layer formed of the thus-prepared polymerized cured film was subjected to a cleaning durability test and an actual printing test of the ink-repellent layer in the same manner as in Example 1. The adhesion to the nozzle plate and the hardness of the ink repellent layer surface were good, and a high quality image was obtained.

(Sixth Embodiment) In the first, second, third, fourth, and fifth embodiments, the case where the nozzle plate 1 in FIG. 1 is made of stainless steel has been described. However, even if the nozzle plate 1 is made of plastic. The inkjet head of the present invention can continuously obtain high quality images. Polysulfone and polycarbonate were adopted as the plastic material, and the excavation of the nozzle hole 2 was performed using an excimer laser. The material forming the ink repellent layer 3 is the same as in Examples 1, 2, 3, 4, and 5, and in the fluorine compound, the reactive group contained in the molecular chain is an epoxy group, an amine, a hydroxyl group, an acid anhydride, or a carboxyl group. Either acid is possible. As the epoxy resin main agent that influences the strength of the bonding force between the ink repellent layer 3 and the nozzle plate 1, a main agent of EA-9460 (Toyoda Gosei) that exhibits a strong bonding force to the plastic material was used. Further, the catalyst 9 or the catalyst 11 was adopted as the epoxy resin curing agent. Catalyst 9
The selection of whether to use or to use Catalyst 11 was determined by the boiling points of the fluorine compounds to be mixed, as shown in Examples 1, 2, 3, 4, and 5. The manufacturing method for forming the ink repellent layer 3 on the nozzle plate 1 is the same as that of the first embodiment described above.
It is the same as 2, 3, 4, and 5.

The thus obtained cleaning durability of the ink repellent layer 3 provided on the nozzle plate 1 made of polysulfone or polycarbonate and the ink jet mounting the nozzle plate 1 on which the ink repellent layer 3 is formed. Using the head, the image quality on the recording paper was examined in the same manner as in Examples 1, 2, 3, 4, and 5.
The cleaning durability of the ink-repellent layer is completely the same as that of the nozzle plate made of stainless steel, and therefore, extremely good results are obtained even in the image quality investigation using the inkjet head equipped with the nozzle plate that has undergone the cleaning durability test. I got it.

In a nozzle plate made of polysulfone and polycarbonate plastic,
The ink-repellent layer of the present invention has repeated cleaning durability, and as a result, the quality of the image formed on the recording paper can be always kept constant and high quality can be maintained for the following reasons. First, as in the case where the nozzle plate material is stainless steel, the epoxy resin forming the ink repellent layer has high adhesion to the nozzle plate, and therefore the ink repellent layer does not peel off from the nozzle plate during the cleaning operation. . Secondly, the rigidity of the ink repellent layer containing the cured epoxy resin is not different from the rigidity that the cured epoxy resin originally has, so even if the cleaning operation is repeated, minute scratches are left on the surface of the ink repellent layer. It never happens. For the above two reasons, the ink repellent performance of the ink repellent layer surface is always uniform and does not deteriorate.

[0027]

The ink jet head of the present invention comprises an ink repellent layer comprising an epoxy resin composed of a main agent and a curing agent, and an epoxy group, an amine, a hydroxyl group, an acid anhydride or a carboxylic acid in the molecular chain. It is formed by polymerizing with a fluorine compound containing. The polymerized cured film obtained by polymerizing the epoxy resin consisting of this main agent and the curing agent and the fluorine compound forms a polymer by the reaction groups contained in the epoxy resin main agent, the epoxy resin curing agent and the fluorine compound reacting with each other. , Becomes an integrated polymer resin. The ink-repellent layer according to the present invention composed of this polymerized and cured film has excellent adhesion to the nozzle plate and excellent rigidity, so that the ink-repellent performance is not deteriorated by repeated cleaning operations. Therefore, the surface of the ink repellent layer at the peripheral portion of the nozzle is always in a stable and uniform surface state, so that the flight direction of the ink droplet ejected from the nozzle hole can always be kept constant.

From the above, the ink jet head of the present invention has the effect of always forming an image of good quality on recording paper. Further, due to the high adhesion property of the epoxy resin forming the ink repellent layer, there is an effect that the material of the nozzle plate is not selected. Further, the rigidity of the ink repellent layer has an effect of facilitating its use even for an ink containing a solid content such as a resin or a pigment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an ink repellent layer formed on a surface of a nozzle plate and a nozzle plate in which nozzle holes are arranged in an inkjet head of the present invention.

FIG. 2 is a diagram showing changes in the contact angle of ink when the ink repellent layer of the inkjet head of the present invention is cleaned.

FIG. 3 is a diagram showing a manufacturing process of forming an ink repellent layer on a nozzle plate of the inkjet head of the present invention.

FIG. 4 is a diagram illustrating a conventional technique.

FIG. 5 is a diagram illustrating a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Nozzle hole 3 Ink repellent layer 4 Discharging surface of ink droplet 5 Pressure chamber side of nozzle plate 6 Resist 7 Resist convex portion 8 Liquid mixed resin 9 Metal nozzle 10 Ink repellent member 11 Resin layer 12 Substrate 13 Partition 14 Orifice 15 Ink tank 16 Heating element 17 Substrate

Claims (2)

[Claims] 1. A nozzle plate having an ink repellent layer formed therein, a nozzle hole, a pressure chamber communicating with the nozzle hole, and pressure generating means for applying an ink ejection pressure to the pressure chamber. In the inkjet head, the ink repellent layer has an epoxy resin composed of a main agent and a curing agent, and fluorine having at least one reactive group of an epoxy group, an amine, a hydroxyl group, an acid anhydride, and a carboxylic acid reactive group in the molecular chain. An ink jet head characterized by being a polymerized and cured film with a compound. 2. A liquid mixed resin obtained by kneading the epoxy resin composed of a main agent and a curing agent and the fluorine compound having any of an epoxy group, an amine, a hydroxyl group, an acid anhydride and a carboxylic acid in a molecular chain, After coating on the surface of the nozzle plate, a functional group contained in the curing agent of the epoxy resin and a reactive group contained in the fluorine compound are polymerized to form the polymerized cured film on the surface of the nozzle plate, or Is a method of polymerizing an epoxy group contained in the epoxy resin and a reactive group contained in the fluorine compound to form the polymerized cured film on the surface of the nozzle plate.