JPH08244233A - Surface treating method for ink jet recording head - Google Patents

Abstract

PURPOSE: To obtain a liquid-repellent layer having excellent liquid repellency, wear resistance and adhesive properties with a base material by filling meltable solid material in a discharge port, providing a conductive layer at least at the peripheral edge of the port, melting the solid layer formed by filling the solid material, and then providing an electrolytic plating layer. CONSTITUTION: Positive type liquid resist is poured in the discharge port 14 of an ink jet recording head 1, and cured. Then, it is masked with a mechanical mask except the port 14 and the surface for surrounding it, and UV-O2 -treated. Then, a first conductive layer is provided at least at the peripheral edge of the port 14 by electroless plating. Thereafter, after the resist poured in the port 14 is removed, a second layer of composite eutectoid plating in which fluorine polymer is dispersed is provided by electrolytic plating. Thus, the introduction of the plating to the port 14 is prevented, and the plating thickness is suitably regulated to obtain the ink jet recording head having a liquid- repellent layer 20 having excellent water repellency, wear resistance and adhesive properties with a base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head of an ink jet recording apparatus for ejecting and ejecting a recording liquid, generally called ink, as small droplets from an ejection port, and adhering the droplets to a recording surface for recording. The present invention particularly relates to a surface treatment method for an ink ejection port provided with an ink ejection port and its peripheral portion.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus for recording information by ejecting a recording liquid (ink) from an orifice (ejection port) of a recording head has been used as a recording apparatus excellent in low noise and high speed recording. Are known.

FIG. 2 is a developed perspective view showing the structure of a normal ink jet recording head.

In this recording head, a discharge pressure generating element 12 is installed on a substrate 11 formed of glass, ceramics or the like, and the discharge pressure generating element is formed by patterning the photosensitive resin cured film 13 by photolithography. A liquid passage 15 and an orifice 14 corresponding to 12 and a liquid chamber 16 are formed.

A top plate 17 formed of, for example, glass, ceramics, or a metal layer is formed on the photosensitive resin cured film 13.
It is laminated and fixed by the adhesive 19. A recording liquid supply port 18 is formed on the top plate 17.

In the recording head having such a structure, the physical properties (physical characteristics) of the surface of the substrate 11, the photosensitive resin cured film 13, and the top plate 17 surrounding the orifice 14 make the recording liquid always stable from the orifice 14. It is extremely important for discharging. That is, when the recording liquid flows around the outer peripheral surface portion (orifice peripheral portion) of the orifice 14 and a liquid pool is generated in a part of the recording liquid, the flying of the recording liquid in the flow path 15 when the recording liquid is discharged from the orifice 14. The direction is separated from the regular predetermined direction, and further, due to the instability of the liquid pool state, the flight direction is disturbed each time it is ejected, which causes a problem that stable liquid ejection cannot be performed. Cannot record.

Furthermore, if the entire outer peripheral surface of the orifice 14 is covered with a film of the recording liquid, a so-called splash phenomenon occurs and the recording liquid is scattered, so that stable recording cannot be performed. Further, if the liquid pool covering the outer peripheral surface of the orifice becomes large, the liquid ejection of the recording head may even become impossible.

Further, in the ordinary recording head as shown in FIG. 2, different materials such as silicon (substrate 1), glass (top plate 17) and resin (photosensitive resin cured film 13) are used. There are many. Then, the recording liquid leaks from the most leaky material of the three types at the peripheral edge of the orifice. With respect to ordinary ink (recording liquid), glass has the lowest interfacial tension with the ink among the above three materials, and the ink leaks from that portion. The glass portion is a material which is usually used because the manufacturing and performance of the head are preferable, and it is not preferable in terms of manufacturing, performance and cost to use another material for the purpose of preventing ink leakage.

As described above, in the conventional recording head, if the recording liquid pools at the peripheral portion of the orifice, stable ejection cannot be performed. Moreover, this tendency becomes extremely remarkable when high-definition recording is performed by increasing the nozzle density or when driving at a high frequency, that is, when high-speed recording is aimed at, in order to improve the performance of the recording head. It's a big problem.

Therefore, as shown in FIG. 1, a so-called liquid-repellent treatment is applied to at least the peripheral portion of the orifice 14 to form a liquid-repellent treatment layer 20 that repels ink, and there is a proposal to solve the above problem. , Has been published a lot from the past.

As one of the methods for solving these problems, conventionally, the outer surface surrounding the discharge port is made of silicone oil,
Water repellency or oil repellency (liquid repellency) by treating with arabic rubber etc.
The method described in JP-B-48-36188 is disclosed.

However, these methods have poor durability because of poor adhesion to the glass, metal, resin or other base material forming the recording head, and the curing is only insufficient.
In addition, the liquid repellency is not sufficient. For example, even if a silicone-based substance exhibits liquid repellency with respect to water-based ink, it is hardly repelled with respect to organic solvent-based ink such as alcohol-based, ketone-based, or ester-based ink. It was not liquid.

Further, an example in which the peripheral portion of the ejection port of the ink jet recording head is treated with fluoroalkylalkoxysilane to make it liquid repellent (Japanese Patent Laid-Open No. 56-895669).
There is also a high temperature (150 ℃ or more) to complete the treatment
Therefore, it is necessary to perform a treatment that may destroy the material forming the discharge port, such as heating for a long time in a high temperature or heating in a high ph solution (for example, an amino solution). In addition, in a conventionally known inkjet recording head that has been subjected to a liquid-repellent treatment, it is performed to wipe off dust and residual ink adhering to the peripheral portion of the ejection port, for example, for rubbing such as wiping operation using rubber or the like. On the other hand, the durability was sometimes insufficient.

[0014]

The liquid-repellent treatment layer 20 formed on the ink jet recording head is not only good in water repellency, but is not the only liquid-repellent treatment layer that is used for recording with an ordinary ink jet recording apparatus. If it is not sufficient in terms of durability, it is not practical. The durability will be described below.

When the ink jet recording method is carried out, the peripheral edge of the orifice is always in contact with the recording liquid even if the peripheral edge of the orifice is subjected to liquid repellent treatment.
It is usual to perform a recovery operation of wiping the orifice surface with an absorber such as polyurethane foam and absorbing the adhered ink. Therefore, the liquid-repellent treatment layer is required to have such adhesiveness that it is not peeled off even if it is rubbed by the absorber and abrasion resistance that is not broken. If the durability is insufficient, the liquid-repellent treatment layer gradually peels off or falls off while the head is in use, so that the liquid-repellent effect is not exhibited, and stable ejection printing is not possible at all in the initial stage. I can not do it.

In the durability required for such an ink jet recording head, a liquid repellent treatment layer formed of a conventional liquid repellent treatment agent may not be sufficient.

Further, when the member surrounding the orifice is made of a plurality of different materials like the ink jet recording head shown in FIG. 2, it is formed of a liquid repellent treatment agent having good adhesion to any of the materials. The liquid-repellent treatment layer must be formed. The water-repellent treatment layer formed of the conventional liquid-repellent treatment agent may be insufficient particularly in this respect.

The present applicant first applied for a liquid repellent treatment agent that solves such a problem. The specification of the application describes an inkjet recording head in which an amorphous thermoplastic fluororesin liquid-repellent layer is coated on a resin via a silane coupling agent or an organic titanate compound.

For example, the head (the substrate 11 is silicon,
When the top plate 17 is formed of glass, a liquid-repellent treatment layer of the resin cured film 13), and the above composition, the liquid-repellent durability and abrasion resistance are improved as compared with the conventional liquid-repellent water-treating agent. A treated layer is obtained.

However, although the above composition has sufficient liquid repellency and durability against wiping with a blade, the liquid repellency may be deteriorated against rubbing with paper when a paper jam occurs.

Therefore, an ink jet recording head having a composite plating on the orifice surface was formed. This is far more improved in abrasion resistance than the liquid repellent treatment of the resin. However, plating only on the peripheral portion of the discharge port sometimes caused peeling or chipping or cracking on the outer edge of the plating.

Further, when plating is performed after forming the discharge ports, the plating may enter the nozzles, resulting in non-discharge or unstable flight direction of ink droplets. Further, when the resist material is filled in the nozzle and the resist material is removed after plating to form the liquid repellent layer, there is a problem that the positive resist cannot be properly removed if the plating layer is too thick.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide liquid repellency, abrasion resistance, and basic property by surface treatment of at least the peripheral portion of the orifice and its outer peripheral portion. It is an object of the present invention to provide a surface treatment method of an inkjet recording head having a liquid repellent treatment layer having excellent adhesion to a material.

[0024]

Therefore, in the surface treatment method for an ink jet recording head according to the present invention, at least in the surface treatment method for an ink jet recording head in which at least the peripheral portion of the ejection port is surface treated, the first ejection is performed. An ink jet recording head, characterized in that the mouth is filled with a dissolvable solid, secondly a conductive layer is provided at least at the peripheral portion of the ejection port, thirdly the solid layer is dissolved, and then an electrolytic plating layer is provided. The above-mentioned object is to be achieved by the surface treatment method described above.

Further, the electrolytic plating layer is formed by complex eutectoid plating in which a fluoropolymer is dispersed, and the object of the present invention is to achieve the above object by the method for surface treatment of an ink jet recording head.

[0026]

With the above-described surface treatment method, at least the peripheral portion of the orifice and the outer peripheral portion thereof are subjected to a base treatment, a conductive first layer is provided by electroless plating, and then a fluoropolymer is formed by electrolytic plating after removing the positive resist. By providing a dispersed composite eutectoid plating second layer, preventing the penetration of plating into the nozzle and adjusting the plating thickness appropriately,
An ink jet recording head having a liquid repellent treatment layer that is excellent in liquid repellency, abrasion resistance, and adhesion to a substrate can be obtained.

Since this surface treatment is a composite plating in which fluorine-based polymer particles are uniformly dispersed and co-deposited, the fluorine-based polymer particles deposited on the surface show excellent liquid repellency.
Since the matrix is a metal, it is much less likely to be damaged than a resin and does not peel off. Furthermore, the thickness of the plating layer is 2
Appropriate durability of the plating layer can be obtained by being able to increase the thickness of the step plating.

[0028]

EXAMPLE In the example of the present invention, at least the peripheral portion of the orifice and the outer peripheral portion thereof are subjected to a base treatment, a conductive first layer is provided by electroless plating, and then a fluoropolymer dispersion is performed by electrolytic plating after removing the positive resist. By providing a second layer of the composite eutectoid plating to prevent the penetration of the plating into the nozzle and to adjust the plating thickness appropriately, the liquid repellency and abrasion resistance, and the liquid repellency excellent in the adhesion to the base material. An inkjet recording head having a treatment layer can be provided.

Since the above surface treatment is a composite plating in which the fluorine-based polymer particles are uniformly dispersed and co-deposited, the fluorine-based polymer particles deposited on the surface exhibit excellent liquid repellency, and the matrix is a metal. Therefore, it is much less likely to be damaged than a resin and does not peel off. Further, in the present invention, since the thickness of the plated layer can be increased by two-step plating, appropriate durability of the plated layer can be obtained.

Example 1 A positive type liquid resist OFP is provided in the nozzle of an ink jet recording head as shown in FIG.
120 ℃ after injecting R800 (Tokyo Ohka Co., Ltd. product)
Cured for 2 hours. Subsequently, a mechanical mask is used to mask the discharge port and the surface surrounding it, and UV / O ₃ treatment is applied to 5
Do for 10 minutes. At this time, the same effect can be obtained by performing plasma asher (100 watt, 1 Torr, 1 min). Next, electroless plating solution Nivodur HXS
(Product of Uemura Kogyo Co., Ltd.) was used at an operating temperature of 90 ° C. and the plating time was adjusted so that the film thickness was 0.2 to 1.0 μm. After that, the positive resist injected into the nozzle was dissolved and removed with acetone. After vacuum drying for 5 minutes, plating treatment was further performed with a plating solution Metaflon (product of Uemura Kogyo Co., Ltd.) CW in which fluorinated graphite was dispersed at an operating temperature of 40 to 50 ° C. The film thickness was set to 1.0 to 25.0 μm by adjusting the plating time and the current density. In this way, an inkjet discharge head was formed.

(Comparative Example 1) A positive type liquid resist OFP is provided in the nozzle of an ink jet recording head as shown in FIG.
120 ℃ after injecting R800 (Tokyo Ohka Co., Ltd. product)
Cured for 2 hours. Next, plating solution Nivodur HX
It was gently dipped in S (product of Uemura Kogyo Co., Ltd.) and plated at an operating temperature of 90 ° C. by controlling the plating time so that the film thickness was 0.2 to 1.0 μm. Further, plating solution Metaflon (product of Uemura Kogyo Co., Ltd.) in which fluorinated graphite is dispersed C
The plating treatment was performed at W at an operating temperature of 40 to 50 ° C. The film thickness was set to 1.0 to 25.0 μm by adjusting the plating time and the current density. Finally, the positive resist injected into the nozzle was dissolved and removed with acetone to form an inkjet discharge head. It should be noted that the same effect can be obtained by providing a convex portion on the outer periphery instead of the groove.

In this way, an ink jet ejection head was formed.

Next, Table 1 shows the results of the "blade rubbing durability test" conducted to examine the abrasion resistance including the liquid contact property of the surface surrounding the discharge port treated by the surface treatment method of the embodiment of the present invention. The "blade rubbing durability test" was carried out by spraying ink on the surface treated with water repellent and rubbing it with a polyurethane blade. The ink was Canoword α-75, and the durability test was performed 300,000 times.

The evaluation was carried out by observing the surface state of the surface treated after rubbing before and after the test with a metallurgical microscope and by printing. ○
The mark indicates that the print condition is good, the mark indicates that the print condition is normal, and the mark indicates that the print condition is bad.

[0035]

[Table 1]

As is clear from the results shown in Table 1, in the recording head of the comparative example, the resist could not be removed when the thickness of the electrolytic plating layer was 15 μm or more. After rubbing 300,000 times, the print quality was slightly degraded. This is because the water repellent layer is slightly peeled off. However, it has sufficient durability and print quality level for the current head life. In addition, heat treatment 120
The initial performance can be recovered by applying the temperature for about 2 hours. In Example 1, the printing is not deteriorated at all and the durability is semi-permanent, which is a performance capable of sufficiently coping with the increase of the printing speed and the prolongation of the life of the head.

[0037]

As described above, according to the surface treatment method of the present invention, stable ejection can be always performed with a substantially uniform liquid amount in a predetermined direction, and a head which can be sufficiently used for high speed recording can be easily formed. It can be formed by processing. Further, by providing the second layer of electrolytic plating after removing the solid such as resist, the total thickness of the plated layer can be increased and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating the appearance of an inkjet recording head.

FIG. 2 is a developed perspective view illustrating the configuration of an inkjet recording head.

FIG. 3 is a cross-sectional view of a plated portion of the inkjet recording head used in Example 1 and Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording head (groove top resin type) 11 Substrate 12 Ejection pressure generating element 13 Photosensitive resin cured film 14 Orifice 15 Flow path 16 Liquid chamber 17 Top plate 18 Ink supply port 19 Adhesive 20 Liquid repellent treatment layer

Claims (2)

[Claims] 1. A method for surface treatment of an ink jet recording head, wherein at least a peripheral portion of an ejection port is surface-treated, first, a soluble solid is filled in the ejection port, and secondly, at least a peripheral portion of the ejection port is electrically conductive. A surface treatment method for an ink jet recording head, comprising providing a conductive layer, thirdly dissolving the solid layer, and then providing an electrolytic plating layer. 2. The surface treatment method for an ink jet recording head according to claim 1, wherein the electrolytic plating layer is formed by complex eutectoid plating in which a fluoropolymer is dispersed.