JPH01195052A - Ink jet head - Google Patents

Abstract

PURPOSE:To simply make an ink introducing passage compatible with ink while simply making an emitting orifice part incompatible with the ink, by covering the inner wall surface of the ink introducing passage with an ink- compatible org. plasma polymerized film and/or covering the emitting orifice part with an ink-incompatible org. plasma polymerized film. CONSTITUTION:The inner wall surface of an ink introducing passage is covered with an ink-compatible org. plasma polymerized film and/or an emitting orifice part is covered with an ink-incompatible org. plasma polymerized film. That is, when the material constituting the ink introducing passage or emitting orifice part is incompatible with ink, the inner wall surface of the ink introducing passage is covered with the ink-compatible org. plasma polymerized film and, when the material constituting the ink introducing passage or emitting orifice part is incompatible with the ink, the emitting orifice part is covered with the ink-incompatible org. plasma polymerized film and, further, if necessary, the inner wall surface of the ink introducing passage is covered with the ink- compatible org. plasma polymerized film and the emitting orifice part is covered with the ink-incompatible org. plasma polymerized film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an inkjet head equipped with an ink transport mechanism that utilizes the capillarity of ink.

[Prior Art and its Problems] In an ink sheet head equipped with an ink transport mechanism that utilizes the capillary phenomenon of ink, when forming an ink introduction path for guiding ink and an ejection port for ejecting ink, conventionally, Generally, various resins such as photosensitive resins, photosensitive glass, various ceramics, etc. have been used as the materials.

In addition, in such an inkjet head, in order to improve ink transport performance and responsiveness, the ink introduction path is made ink-philic, while at the ejection port part, in order to suppress ink dripping, It was considered preferable to make the material ink-phobic.

When forming the ink introduction path and ejection port with resin, if an ink-philic resin is used to improve the transportability of the ink, the ink may penetrate into the resin after long-term use, resulting in These parts may swell and become deformed, and during use, mold may form and the material may change in quality, making it impossible to eject ink stably and uniformly. Ta. In addition, when the ejection port portion is formed of an ink-philic resin, there is a problem in that ink drips at the ejection port portion.

On the other hand, when forming the ink introduction path and ejection port using photosensitive glass, fine processing can be applied because the resolution of photosensitive glass is poor, and as in the case of resin, There was also the problem that mold formed during use and the material deteriorated.

For this reason, in the past, the ink introduction path and the ejection port were made of different materials, and these were connected together, or the ink introduction path or the ejection port was coated with a resin with different properties from the material. it was thought.

However, it is very difficult to form the ink introduction path and the ejection port portion using different materials and to connect them well, resulting in problems such as poor workability. Furthermore, it is difficult to apply a resin with different properties to the ink introduction path or ejection port because the ink introduction path or ejection port is minute, and in addition, depending on the resin used, A similar problem occurred when the resin was used.

Furthermore, since ceramics and the like are inherently hydrophilic, it is necessary to perform an ink-repellent treatment on the tip of the ejection port, which is suitable only for aqueous ink, which causes the same problem as above.

The purpose of this invention is to solve the various problems mentioned above, and it is possible to easily solve the problems no matter what material the ink introduction path or ejection port of the ink sheet head is made of. By making the ink introduction path ink-philic and the ejection port part ink-phobic, these parts do not deform or change in quality, allowing ink to be ejected stably and uniformly over a long period of time. The purpose of the present invention is to provide an inkjet head that can

1. Means and operation for solving the problem] This invention has the following features:
In an inkjet head equipped with ink transport AWI that utilizes ink capillarity, the inner wall surface of the ink introduction path is coated with an ink-philic organic plasma polymer film, and/or the ejection port portion of the inkjet head is coated with an ink-phobic organic plasma polymer film. This was done so that the material could be coated.゛That is,
When the material forming the ink introduction path and the ejection port is ink-phobic, the inner wall surface of the ink introduction path is coated with an ink-philic organic plasma polymer film, while the material forming the ink introduction path and the ejection port is coated with an ink-philic organic plasma polymer film. In the case of ink-philic properties, the ejection port portion is coated with an ink-phobic organic plasma polymer film, and if necessary, the inner wall surface of the ink introduction path is coated with an ink-philic organic plasma polymer film. At the same time, the discharge port portion was coated with an ink-phobic organic plasma polymerized film.

In this way, depending on the material forming the ink introduction path and the ejection port, the ink introduction path can be easily made ink-friendly by simply coating the appropriate parts with an ink-friendly or ink-phobic organic plasma polymer film. In addition, the ejection port portion can be made ink-phobic, the ink transportability is improved, and ink dripping at the ejection port portion can be suppressed.

In addition, when coated with an organic plasma polymerized film in this way,
The organic plasma polymerized film does not swell or change in quality due to ink, and has good adhesion to the base material, so it is resistant to the effects of heat and electric fields and mechanical vibrations caused by piezoelectric vibrators, etc. It is strong against water, can be used for a long period of time, and ink is ejected stably and uniformly.

When coating the inner wall surface of the ink introduction path or the ejection port with an ink-philic or ink-phobic organic plasma polymer film, water-based inks and oil-based inks have different ink-philic and ink-phobic properties, so Depending on the type of ink to be used, an ink-philic or ink-phobic organic plasma polymerized film is provided. For example, in the case of water-based ink, the inner wall surface of the ink introduction channel is coated with a hydrophilic organic plasma polymerized film, and the ejection port is covered with a hydrophobic organic plasma polymerized film, while in the case of oil-based ink, this is coated with a hydrophilic organic plasma polymerized film. Conversely, the inner wall surface of the ink introduction path is covered with a hydrophobic organic plasma polymerized film, and the discharge port portion is covered with a hydrophilic organic plasma polymerized film.

In addition, in forming a hydrophilic organic plasma polymerized film, for example, when performing a plasma reaction, oxygen compound scum or nitrogen compound gas is introduced and chemical modification is performed to make the organic plasma polymerized film hydrophilic. It can also be formed by containing oxygen atoms or nitrogen atoms as a substance.

Here, the amount of oxygen atoms and nitrogen atoms contained in the organic plasma polymerized film can be adjusted by increasing or decreasing the amount of oxygen compound gas and nitrogen compound residue introduced during the plasma reaction, and the content are both 0.1 atomic%
That's fine. The reason why the content is set to 0.1 atomic % or more is that if the content is 0.1 atomic % or less, it is difficult to see a difference from a film that does not contain these elements. on the other hand,
Is there any particular restriction on the maximum content of these substances?
If it exceeds 20 atomic %, the film quality of the organic plasma polymerized film will be poor and it will be difficult to meet the requirements, so it is preferably 20 atomic % or less.

In addition, organic plasma polymerized film (hereinafter abbreviated as a-C:X
It is called a membrane. Note that X is a modified atom. ) as a-
When forming a C:H film or a-C/halogen film, even if a large amount of rare gas such as argon or helium is mixed in as a carrier gas to form an organic plasma polymerized film, an even more hydrophilic organic A plasma polymerized film is formed, and after forming an a-C:H film or an a-C:halogen film as an organic plasma polymerized film, the surface of this organic plasma polymerized film is treated with oxygen, nitrogen, etc. It is also possible to impart hydrophilicity to the organic plasma-polymerized film by bombarding it with gas plasma.

On the other hand, in forming a hydrophobic organic plasma polymerized film, when performing a plasma reaction, hydrocarbon scum, mixed scum of hydrocarbon gas and halogen atom-containing hydrocarbon gas, halogen atom-containing carbon compound scum, etc. , or a combination of these is introduced to form an organic plasma polymerized film.

When introducing hydrocarbon gas, the amount of hydrogen atoms contained in the organic plasma polymerized film is approximately 10 to 60 at% based on the total amount of atoms, and the amount of hydrogen atoms contained in the organic plasma polymerized film is approximately 10 to 60 at%, and the amount of hydrogen atoms contained in the organic plasma polymerized film is approximately 10 to 60 at%. When introducing a gas, the content of halogen atoms contained in the organic plasma polymerized film is 0.
It is preferable that the content is 1 to 60 atomic %.

[Example] Hereinafter, an example of the present invention will be specifically described based on the accompanying drawings.

First, an example of the slit type inkjet head shown in FIGS. 1 and 2 (A) and (B) will be described.

In this example, a flat plate of Macol (manufactured by Corning Inc.) made of glass ceramic and having a thickness of 2 mm is used as the base material (10), and one side of the base material (10) that is the discharge port side is tapered. After cutting into this base material (10)
Using a dicing saw, cut jlI (11) for the ink passage, which has a width of 60 μm, a groove depth of 120 μm on the flat plate part, and a groove depth of 60 μm on the tapered discharge port side, to 60 μm. Cut the required number of pieces at a pitch of
A required number of 60 μm ejection ports (13) were formed.

Then, in each groove (11) for the ink passage formed in the base material (10) in this way and the upper plate (12) disposed on this base material (10), excluding the ejection port (13) portion. The ink introduction path is covered with an ink-philic organic plasma polymerized film (
14a), an ink-phobic organic plasma polymerized film (14b) is formed on the ejection openings (13), and a well-known film is formed on the bottom of each groove (11) for the ink passage. By sputtering method, the vertical and horizontal dimensions are 3
A 0 μm chromium individual mold & (15) was inserted into the above discharge port (
13) It was arranged to be formed at a position 20 μm apart.

Here, in this example, since a commonly used aqueous ink having a composition shown in Table 1 below was used as the ink, the ejection port (13)
On the other hand, a hydrophilic organic plasma polymerized film was formed on the ink introduction path portion except for the ink introduction path portion, while a hydrophobic organic plasma polymerized film was formed on the ejection port (13) portion.

Table 1 Here, in forming a hydrophilic organic plasma polymerized film, the following two methods were used using a known plasma CVD apparatus, and the contact angle of the aqueous ink was measured for each method.

First, in the first method, the raw material (monomer) is 1,3-
Butadiene monomer was introduced at a flow rate of 60 sccm, and hydrogen gas was introduced as a diluent gas at a flow rate of 300 seconds, at a pressure of 0.7 Torr and a voltage of 180 W.

Gas plasma treatment was performed at room temperature for 38.4 minutes at a frequency of 2 MHz to form a 5 μm plasma polymerized film, and then the gas was changed to oxygen gas and oxygen plasma treatment was performed for 1 minute. The contact angle of the aqueous ink with the thus obtained hydrophilic organic plasma polymerized film was 18°.

In the second method, isoprene monomer as a raw material (monomer) is introduced at a flow rate of 60 seconds, oxygen gas is introduced as a dope gas at a flow rate of 5 seconds, and hydrogen gas is introduced as a diluent gas at a flow rate of 25 Qsccm, and the pressure is 0.9 Torr.
After forming a plasma polymerized film of 4 μm by performing gas plasma treatment at a temperature of 40°C under the conditions of voltage 180 W and frequency 800 K HZ, the gas was changed to oxygen and heated for 1 minute and 3 minutes.
Oxygen plasma treatment was performed for 0 seconds. The contact angle of the aqueous ink with the hydrophilic organic plasma polymerized film thus obtained was 13°.

In this way, even if a hydrophilic organic plasma polymerized film is formed in the ink introduction path except for the ejection port (13) by any of the above methods, the contact angle of the aqueous ink becomes small and the ejection becomes difficult. The aqueous ink flowed easily in the ink introduction path except for the exit port 13).

Further, in forming a hydrophobic organic plasma polymerized film, the following two methods were used using a known plasma CVD apparatus, and the contact angle of the aqueous ink was measured for each method.

First, in the first method, perfluoropropylene monomer (C3F6) as a raw material (monomer) is supplied at a flow rate of 50 se
At the same time, hydrogen gas was introduced as a diluting gas at a flow rate of 250 sec, and the pressure was 0.6 Torr.

Gas plasma treatment was performed for 32.5 minutes at room temperature under conditions of a voltage of 175 W and a frequency of 600 KH2 to form a plasma polymerized film of 5 μm. The contact angle of the aqueous ink with the hydrophobic organic plasma polymerized film thus formed was 99°.

-13~ In the second method, carbon tetrafluoride scum (CF4) as a raw material (monomer) is introduced at a flow rate of 60 sec, and helium scum is introduced as a diluent gas at a flow rate of 300 sccm, and the pressure is 0.7
Gas plasma treatment was performed for 399 minutes at a temperature of 40° C. under the conditions of Torr, voltage of 200 W, and frequency of 500 KH2 to form a plasma polymerized film of 4 μm.

The contact angle of the aqueous ink with the thus obtained hydrophobic organic plasma polymerized film was 110°.

In this way, even when a hydrophobic organic plasma polymerized film is formed at the ejection port (13) by any of the above methods, the contact angle of the water-based ink becomes large, and the water-based ink becomes larger at the ejection port (13). Parts of the liquid have stopped leaking, and there is no longer any leakage.

In addition, when an oil-based ink shown in Table 2 below is used as an ink, it generally exhibits ink-philicity toward the oil-based ink or a hydrophobic organic plasma polymerized film; In order to show ink repellency to the film, contrary to the above case, the ink introduction path except for the ejection port (13) is coated with a hydrophobic organic plasma polymerized film, while the ejection port (13) The portion is coated with a hydrophilic organic plasma polymerized membrane.

Table 2 Also, in this example, the above upper plate (12)
When placing the ink passages on the base material (10), a small gap is provided between the upper plate (12) and the base material (10), and each groove (11) for the ink passage is connected to the upper plate (12). Make sure to prevent ink from clogging in between.

Next, as shown in FIG. 1, the inkjet head component formed in this way is connected to a discharge port (13) having a working electrode at its tip with an opposing type & (16) with an interval of 185 μm. They were placed so as to face each other, and ink sheet recording was performed.

In this ink-shet recording, an electrode pulse application voltage of -200 μ is applied to the individual electrodes (15) provided in the constituent parts of the grooves (11) using a multi-stylus driving method, that is, each groove (11) The tens to hundreds of individual electrodes (15) provided at the bottom of the groove are divided into several flocks, and a drive IC is mounted corresponding to each block. Based on the drive IC, an individual type fi ( 15) -2
Be sure to apply a pulse voltage of 00V. On the other hand, in response to this, a pulse voltage of +400 cm is uniformly applied to the counter electrode (16), and the - charged flying ink (
17) was electrostatically attracted, and ink jet recording was performed on a recording paper (19) that was supplied by a roller (18) to the inkjet head component side of this counter electrode (16).

As a result, when this inkjet head was used, ink was ejected stably and uniformly, and a good inkjet image was formed.

In this example, a flat plate made of glass ceramic was used as the base material (1o), and it was cut using a tie sink saw, but in order to increase the pixel density, grooves (11) for ink passages were added. In the case where the ink passages are formed at a pitch of 20 to 40 μm, cutting is difficult, so a thin film of silicon dioxide or the like may be formed and the holes (11) for the ink passages may be provided on this by etching. . Also,
It is also possible to create a mold using laser beam processing, etc., and use that mold to stamp or cast the base material with resin, etc. In this case, manufacturing costs can be reduced. can be done.

Next, an example of the slit type inkjet head shown in FIGS. 3A and 3B will be described.

This example is different from the above example in that the groove (11) for the ink passage is not formed like in the above example, and the ejection port (13) is a slit. The other points are the same as those of the above embodiment, and an ink-philic organic plasma polymerized film (14a) is formed on the ink introduction path except for the ejection port (13). An ink-phobic organic plasma polymerized film (14b) was formed at the ejection port (13).

Further, FIG. 4 shows an example of an inkjet head of the Huffle Sheet 1 system, in which air bubbles are generated in the nozzle (21) by a heating resistor (20), and ink is ejected by the pressure of the air bubbles.

In this ink sheet head, as in the case of the above-mentioned embodiment, an ink-philic organic plasma polymerized film (], 4a), while the discharge port (13)
An ink-phobic organic plasma polymerized film (14b) was formed on the portion.

Further, FIG. 5 shows an example of a pulse jet type ink shed head using a piezoelectric element (22).

In this inkjet head, the ink-philic organic plasma polymerized film (14a) is not applied to the inner wall surface of the nozzle (21) except for the ejection port (13), but rather to the capillary tube (23) through which the ink is guided. Tank (24)
The inner wall surface of the ink-philic organic plasma polymerized film (14a
), and the ejection port (13) portion is covered with an inkphobic organic plasma polymerized film (
14b).

[Effects of the Invention] As detailed above, in the inkjet head according to the present invention, appropriate areas are treated with ink-philic or ink-phobic organic plasma depending on the material constituting the ink introduction path and the ejection port. Because it is coated with a polymer film,
No matter what material is used for the ink introduction path or the ejection port, it is now possible to easily make the ink introduction path ink-philic and the ejection port portion ink-phobic.

As a result, no matter what material is used to form the ink introduction path or the ejection port, Infusiera 1 has high ink transportability, excellent responsiveness, and no ink dripping at the ejection port. You can now get 1 or more,
Furthermore, materials with good workability can be used to form the ink introduction path and the ejection port, making manufacturing easier.

In addition, when coated with an organic plasma polymerized film like this,
The organic plasma polymerized film does not swell or change in quality due to ink, and is also resistant to the effects of heat and electric fields.
It has become possible to obtain an ink sheet spatula 1 which can be used for a long period of time because it is resistant to mechanical vibrations caused by piezo vibrators and the like, and which can eject ink stably and uniformly.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a state in which inkjet recording is performed using a slit-type inkjet head according to an embodiment of the present invention, and FIGS. 2A and 2B show an inkjet head of the same embodiment. Cross-sectional view and front view, Figure 3 (
A) and (B) are a cross-sectional view and a front view of a slit-type inkjet head according to another embodiment, FIG. 4 is a cross-sectional view of a bubble-jet-type inkjet head according to another embodiment, and FIG. FIG. 2 is a cross-sectional view of a pulse jet inkjet head according to another embodiment. (10) Base material, (11) Groove for ink passage, (12) Upper plate, (13) Discharge port, <14
a> Ink-philic organic plasma polymerized film, (14b)
...Ink-phobic organic plasma polymerized film, (15)...
・Individual electrode, (20)...heating resistor, (21)...
- Nozzle, (22)...Piezoelectric element, (23)...Capillary tube, (24)...Ink tank. Patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Katsuaki Matsukawa Figure 3 (A) Q (B) , 12 Figure 4 Figure 5

Claims (1)

[Claims] 1. In an inkjet head equipped with an ink transport mechanism that utilizes ink capillarity, the inner wall surface of the ink introduction path is made of an inkphilic organic plasma polymer film, and/or the ejection port portion of the inkjet head is made of an inkphobic organic plasma polymer film. An inkjet head component characterized by being coated with a polymer film.