KR20080095335A - Manufacturing method of nozzle of inkjet head - Google Patents

Abstract

A method of manufacturing a nozzle of an ink-jet head is provided to smoothly form the meniscus of ink by depositing a water-repellent layer only on the nozzle surface of the ink-jet head with physical vapor deposition such as evaporation. A method of manufacturing a nozzle of an ink-jet head comprises a step(100) of preparing the ink-jet head structure in which a nozzle is punched on the nozzle surface; a step(110) of determining the deposition time in order to deposit a water-repellent material on the inside of the nozzle below the critical thickness to have water repellency; and a step(120) of depositing the water-repellent material on the ink-jet head structure for a predetermined deposition time by using physical vapor deposition having the directivity towards the nozzle surface.

Description

Manufacturing method of nozzle of inkjet head

1 and 2 is a flow chart showing a water repellent layer manufacturing process according to the prior art.

3 is a cross-sectional view showing a state in which a water repellent layer is deposited on an inkjet head nozzle.

Figure 4 is a flow chart showing a nozzle manufacturing method of the ink jet head according to a preferred embodiment of the present invention.

5 is a schematic view showing a deposition process according to a preferred embodiment of the present invention.

6 is a cross-sectional view showing a nozzle of an ink jet head according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: inkjet head 3: source

120: nozzle surface 121: the inside of the nozzle

122: nozzle 141: water repellent layer

The present invention relates to a method for producing a nozzle of an inkjet head.

In inkjet heads used in industrial and printer applications, ink is ejected in the form of droplets, and ink must be stably ejected in the form of complete droplets in order to increase the printing performance of the inkjet head. To this end, the nozzle area should be water-repelled (Hydrophobicity) so that the meniscus of the ink can be smoothly formed.

Conventionally, a method of forming a nozzle by electroplating and a method of forming a nozzle by micro punching and polishing processes have been used for the water repellent treatment of a nozzle of an inkjet head. The outlet portion of the nozzle manufactured by these methods is an important factor in the size of the ink droplets ejected from the inkjet head, the ink ejection performance, the ink ejection stability, and the continuous ejection. However, the above-described methods have a problem that the process is complicated and difficult to manage process conditions, and does not apply to nozzles of various shapes.

If the surface of the nozzle does not have water repellency, wetting occurs that the surface of the nozzle becomes wet as the jet of ink is repeated. When such a wetting phenomenon occurs, the ejected ink forms lumps with the wet ink on the nozzle surface, and the ejected ink is ejected in such a manner that the ejected ink flows down without having a perfect droplet form. The meniscus formed after the injection is also unstable. In other words, in order to secure the reliability of the inkjet head, it is essential to water repellent the nozzle surface.

In order to semi-permanently regenerate the nozzle surface of the inkjet printer head, conventionally, a method of plating a water repellent material in a plating bath in which a predetermined length is applied is used. Teflon-based materials are mainly used as the water repellent material, and a typical one of the Teflon-based materials is PTFE (Polytetrafluroethylene). In order to use the PTFE for water repellent treatment of the nozzle surface, a PTFE composite plating process is used in a plating bath in which electric field is applied under a certain condition.

However, since the water repellent treatment method by the composite plating is not directed, the water repellent layer is formed by plating not only the nozzle surface on which the water repellent layer should be formed, but also the inside of the nozzle where the water repellent layer should not be formed. Therefore, when the water repellent treatment is performed by the composite plating method, a pretreatment for preventing the water repellent layer from forming inside the nozzle is further required.

Conventionally, as shown in Fig. 1, in order to make the water repellent treatment only on the nozzle surface, after forming the insulating film 12 with a non-conductor inside the nozzle, the water repellent layer 14 is plated to form a water repellent layer inside the nozzle. The method of avoiding this was used. At this time, a representative material used as the insulating film 12 is a photoresist, and as shown in FIG. 1, before the water repellent treatment is applied to the nozzle surface, the photoresist is first applied to the rear surface of the nozzle by a method such as screen printing. After the formation, the water repellent layer 14 such as PTFE was formed on the surface of the nozzle by a composite plating treatment step which is a general method.

In addition, as shown in FIG. 2, a method of forming a uniform non-conductive thin film 32 on the back of the nozzle by using the straightness of vacuum deposition and plating the water repellent material on the entire surface of the nozzle was used. That is, as shown in FIG. 2, before the water repellent treatment is performed on the nozzle, the non-conductive thin film 32 is formed on the rear surface of the nozzle by vacuum deposition, and the Teflon-based water repellent material is plated on the nozzle surface to form the water repellent layer 34. It is formed, and the nozzle is heat treated to complete the water repellent treatment of the nozzle.

As described above, the above-described methods are used to form the water repellent layer on the nozzle of the inkjet head. However, it is difficult to completely prevent the water repellent layer from being deposited on the back of the nozzle, and it is difficult to water repellent the nozzles with uniform depth. Accordingly, there is a problem that the droplet size is not uniform or the reliability of the repeated printing is lowered when the droplet is sprayed after the water repellent treatment.

The present invention provides a nozzle manufacturing method of an ink jet head which simplifies the process by selectively depositing a water repellent layer only on the nozzle surface of the ink jet head by a directional physical vapor deposition method.

According to an aspect of the present invention, by depositing a water-repellent material in the ink jet head structure for a predetermined deposition time using a step of providing an ink jet head structure in which the nozzle is perforated on the nozzle surface, and a physical vapor deposition method having a direction toward the nozzle surface Including the step of, the deposition time is provided a nozzle manufacturing method of the inkjet head, characterized in that the water-repellent material deposited inside the nozzle is determined to be deposited thinner than the critical thickness having a water repellent.

The inkjet head structure may be manufactured by bonding a plurality of substrates formed by etching a silicon substrate. The deposition method may be an evaporation method. The water repellent material may be formed of an F-based or Si-based polymer material, and the critical thickness may be a preset value corresponding to the material of the water repellent material, for example, 40 angstroms.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

Hereinafter, a preferred embodiment of the nozzle manufacturing method of the inkjet head according to the present invention will be described in detail with reference to the accompanying drawings, in the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and Duplicate description thereof will be omitted.

3 is a cross-sectional view showing a state in which a water repellent layer is deposited on the nozzle for the ink jet head, Figure 4 is a flow chart showing a nozzle manufacturing method of the ink jet head according to a preferred embodiment of the present invention, Figure 5 is a preferred embodiment of the present invention Figure 6 is a schematic diagram showing a deposition process according to, Figure 6 is a cross-sectional view showing a nozzle of the ink jet head according to a preferred embodiment of the present invention. 5 and 6, an inkjet head 1, a source 3, a nozzle face 120, an inner side 121 of the nozzle, a nozzle 122, and a water repellent layer 141 are illustrated.

The water repellent layer 141 of the ink jet head nozzle 122 is formed as shown in FIG. That is, the water repellent layer 141 formed by depositing the water repellent material is usually stacked up to several micrometers by the nozzle 122 inlet and the inside 121 of the nozzle. The present embodiment facilitates the water repellent treatment of the nozzle 122 by depositing a water repellent layer 141 on the completed nozzle surface 120 using a physical vapor deposition method having an orientation such as evaporation. It is characterized by improving the yield by improving the uniformity between (122).

In forming the water repellent layer 141 by depositing a water repellent material, it is important to selectively coat the water repellent layer 141 only on the nozzle face 120 or only to a suitable depth from the nozzle face 120. Since the water repellent layer 141 is formed after the inkjet head 1 structure is formed, foreign matter may enter the inside of the head when the photolithography process or the cleaning process is performed, thereby improving the yield of the head. Is degraded.

In the selective coating of the water repellent layer 141, first, in the case of a head manufactured by bonding silicon, the bonding temperature is high, so that the water repellent layer 141 may be deposited after the bonding process, and second, the water repellent layer 141 is deposited after the bonding process. In the process, the cleaning process due to the wet (wet) process should not be additionally required. Third, the position where the water repellent layer 141 is deposited should be located exactly at the end of the nozzle 122 and also maintain the uniformity. The conditions for coating with sufficient water repellent should be met.

According to the present embodiment, in order to manufacture the nozzle 122 for the inkjet head satisfying the above conditions, first, the nozzle surface 120 is provided with the inkjet head 1 structure in which the nozzle 122 is perforated (100). . For example, when the inkjet head 1 is manufactured by etching a silicon substrate using a semiconductor process, an upper substrate on which the chamber is processed, an intermediate substrate on which the restrictor and the ink flow path are processed, and a lower substrate on which the nozzle 122 is drilled The head structure can be manufactured by fabricating and bonding to silicon direct bonding. Depending on the design, a larger number of substrates may be processed and bonded, or only upper and lower substrates may be processed and bonded. Alternatively, a head structure may be formed by processing a metal substrate such as stainless rather than a silicon substrate.

Next, the water repellent layer 141 is formed by depositing a water repellent material toward the nozzle surface 120 of the inkjet head 1 by a physical vapor deposition method such as evaporation. That is, the F- or Si-based water repellent material is deposited in a state where the structure of the inkjet head 1 is completed. 5 is a schematic diagram showing a deposition process by evaporation.

The evaporation method is a method of physical vapor deposition, in which a material to be deposited is contained in a source 3 and evaporated in a vacuum so as to be deposited on the nozzle face 120 of the head to be deposited. In general, the physical vapor deposition method has a poor step coverage, unlike chemical vapor deposition (CVD). Step coverage refers to the ratio of the coated degree of the inclined step portion to the flat portion when various thin films are coated, and in a general semiconductor process, a chemical vapor deposition method is applied to increase the step coverage.

However, in the present embodiment, in order to selectively coat the water repellent layer 141 only on the nozzle surface 120, a physical vapor deposition method having a poor step coverage, for example, an evaporation method, is applied. When the physical vapor deposition method is used, as shown in FIG. 6, the water repellent layer 141 is uniformly deposited on the portion facing the source 3, that is, the nozzle surface 120, while the inside 121 of the nozzle is not formed. It can be seen that the water repellent layer 141 is not deposited as much as the nozzle surface 120. As described above, the water repellent layer 141 is deposited only on the nozzle surface 120 and the water repellent layer 141 is not deposited on the inside 121 of the nozzle using the step coverage characteristic of the physical vapor deposition method.

When the water repellent material is deposited for a predetermined time by evaporation, a water repellent material having a predetermined thickness is deposited on the nozzle surface 120 to have water repellency, thereby forming a water repellent layer 141. Therefore, according to the present embodiment, selectively depositing the water repellent layer 141 only on the nozzle surface 120 not only causes the water repellent material to be deposited on the nozzle surface 120 to function as the water repellent layer 141. Even if the water repellent material is deposited on the inside 121 of the nozzle, the concept includes including adjusting 110 to be thinner than a critical thickness that may have water repellency. That is, by controlling the evaporation time, the water repellent material is deposited on the nozzle surface 120 or more above the critical thickness, and the water repellent material is not deposited on the inside 121 of the nozzle or thinner than the critical thickness even when deposited.

For example, a polymer material containing F or Si as a water repellent material is accommodated in a crucible heated by crucible or e-beam and evaporated in a high vacuum of 10 ^-6 torr or higher to obtain a water repellent material. It is deposited on the nozzle face 120. When the F- or Si-based polymer material has water repellency at a thickness of at least 40 angstroms or more, when the evaporation time is controlled to control the deposition thickness of the water-repellent material deposited on the nozzle surface 120 to 40 angstroms, the nozzle It is possible to prevent the water repellent material is deposited on the inner 121 of, or even if the water repellent material is deposited.

As a result, the water repellent layer 141 may be selectively formed only on the nozzle surface 120 of the inkjet head 1. In the above example, the thickness of the water repellent material, that is, the critical thickness, may vary depending on the material of the water repellent material.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention.

As described above, according to a preferred embodiment of the present invention, by selectively depositing the water repellent layer of the inkjet head by a physical vapor deposition method having a low directional step coverage effect such as evaporation (evaporation) to selectively repel water The layer may be deposited, and excellent hydrophobicity treatment may be performed to facilitate the meniscus formation of the ink.

In addition, the conventional photolithography method and the multi-step patterning process can be omitted for selective water repellent layer deposition, thereby reducing the processing time and cost, and working in various chemical liquids. Since the wet process is omitted, various liquids can be introduced into the nozzle to prevent unnecessary cleaning processes from being added.

Claims (5)

Providing an inkjet head structure in which the nozzle is perforated on the nozzle face; And And depositing a water-repellent material on the inkjet head structure for a predetermined deposition time by using a physical vapor deposition method having a direction toward the nozzle surface. Wherein the deposition time is determined so that the water repellent material deposited inside the nozzle is deposited to be thinner than a critical thickness having water repellency. The method of claim 1, The inkjet head structure is a nozzle manufacturing method of the inkjet head, characterized in that the manufacturing by bonding a plurality of substrates formed by etching the silicon substrate. The method of claim 1, The deposition method is a nozzle manufacturing method of the ink jet head, characterized in that the evaporation (evaporation) method. The method of claim 1, The water-repellent material is made of an F-based or Si-based polymer material, the critical thickness is a nozzle manufacturing method of the inkjet head, characterized in that the preset value corresponding to the material of the water-repellent material. The method of claim 1, And the critical thickness is 40 angstroms.

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