JPS59142157A - Recording head - Google Patents

Abstract

PURPOSE:To obtain a recording head having ink jet orifices whose chemical and mechanical durability is large and whose working precision is high by a construction wherein a water-repellent layer formed of a specific material is provided on a surface on which ink jet ports are formed. CONSTITUTION:The above purpose can be achieved by a construction in which a water-repellent layer formed of an amorphous material containing silicon and carbon in the main is provided on a surface 13 in which ink jet ports are formed in an ink-jetting recording head of an ink jet recording device. A surface layer composed, as the most preferable mode, of amorphous hydrogen and silicon carbide fluoride (a-Si1-xCx:H,F) which are formed by using amorphous silicon carbide as a main component and making preferably fluorine and more preferably hydrogen contained is formed on the surface 13 in which the ink jet ports are formed. The carbon content of the amorphous silicon carbide is 5-50 atom %. An amorphous state defines the state in which no crystalline portion exists in an entire material, or the state in which microcrystalline regions are scattered partly in the material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inkjet recording device, and more particularly to an improvement in a recording head that ejects ink in the device.

(Prior Art) As the need and amount of information recording increases, non-impact recording methods that reduce the operating noise of recording devices and printing noise are welcomed in places where recording is mainly required, especially when high-speed recording is required. The inkjet recording method, which allows the use of plain paper without requiring print fixing, is attracting a lot of attention as a method that matches the social situation.

The inkjet recording method is a recording method in which ink is ejected from a recording head driven by an electric signal toward a recording medium such as paper to draw images such as characters and figures on the recording medium.

Such inkjet recording methods can generally be divided into two types.

That is, in the first method, ink droplets are generated using a continuous vibration generation method such as ultrasonic waves, an electric charge is applied to the ink droplets, and the flight trajectory of the ink droplets is controlled by a deflection electrode, and the necessary ink droplets are selected and displayed at the pixel. Either by placing an ink droplet at a point, or by applying an electric field between the lip of the jet orifice and a ring-shaped electrode, the scattering range of the ink droplets generated in the form of a mist is determined by the continuous vibration generation method, centered around the jet orifice axis. A method of forming a record by two-dimensional density variation of the number of ink droplets passing through an aperture within a predetermined cone diameter, as disclosed in US Pat. No. 3,060.
No. 429, No. 3.59'6,275, No. 3298.030, No. 3,416,153, etc.

Another second method is the so-called drop on d'emand method, which
This is a shooting type recording method in which all the generated ink droplets are placed on controlled or restricted trajectories to land at predetermined pixel points without waste.

The ink droplets used in this method are produced by, for example, a piezo vibrating element installed in the recording head generating mechanical vibrations in immediate response to an electric pulse signal, which quickly increases the pressure of the ink mother liquid at the ejection orifice. ejected as ink droplets from the ink. This method has attracted a lot of attention because it does not require the recovery of vane ink compared to the first method mentioned above, and is disclosed in U.S. Pat. Nos. 3,683,212 and 3,747.
, No. 120 and No. 3,946,398.

In any of the above-mentioned inkjet recording methods, the surface where the ejection ports of the recording head that ejects ink are formed, that is, the surface that surrounds the ink ejection ports and is exposed to the outside, is critical to the inkjet recording method. It has important importance.

In other words, the stability of the ink flight characteristics from the recording head, more specifically, the stability of the shape of the ink droplets reaching the recording medium, the stability of the ink flight speed, etc. are guaranteed, and the image density is uniform and there is no image distortion. Records with excellent image quality such as these can be obtained. For this purpose, the surface wetting of the ink mother liquor at the end of the ejection orifice, which contacts the ejected ink and determines various factors when the ink leaves the recording head, in other words, forms the surface that forms the ink ejection port. There are strict requirements for physical or electrochemical corrosion resistance, deformation due to sticking to obstacles, and prohibitions against deterioration, and additional requirements are added for mechanical and structural strength against ink internal pressure, continuous vibration, or electrical shock. . Moreover, in order to meet the above-mentioned strict requirements, it is necessary that the material be easy to process and have good processing accuracy.

It is no exaggeration to say that the wetting characteristics, deformation, and deterioration of the surface on which the ink jetting ports are formed are critical to the life and death of an inkjet recording device. If the material base is exposed, the contact angle with the ink is small, and the periphery of the ink jet orifice and its vicinity will be wetted with ink. Once wetting occurs in these areas, the size and velocity of the ink droplet and its resistance to ink droplet formation change over time during successive ink droplet ejections due to the surface tension of the ink. The ejection interval fluctuates, the ejection direction is disturbed, and the control over the flight of ink droplets becomes unbalanced, making it impossible to obtain high quality recorded images. In addition, changes in wetting characteristics due to drying and solidification of the ink that wets the surface where the ink jet ports are formed, or deformation and alteration due to chemical corrosion of the core further aggravate the above-mentioned loss of control.

To address the above-mentioned disadvantages, water-repellent treatment is performed on the surface on which the ink jetting ports are formed, such as a silicone-based face that is vapor-deposited or coated with a fluorine-based polymer or oligomer, or a coating made of oil or a silazane-based compound. Applying agent (4? Kaisho 55-148170),
Alternatively, it is possible to apply a silane coupling agent or an organic titanium compound coating agent (Kokai 55-161668).

However, the coating agents that are applied are mainly in liquid form, which requires heat treatment to harden and impart water repellency after application, which complicates the production process.Also, organic coating agents cannot be treated at high temperatures and are durable over time. inferior to sex.

Furthermore, fluorine-based polymers have insufficient water repellency to ink, and silane coupling agents deteriorate due to long-term immersion in ink.

Furthermore, the above-mentioned coating agents generally have poor adhesion to substrates and mechanical strength against contact with paper fibers, rubber caps, and the like.

In addition, other technological efforts have been made to make the nozzle part using water-repellent materials, such as doping and curing the fluorine-based oligomer, silicone oil, or silazane-based compound into epoxy resin, phenol resin, or polyester resin. There is an example (Japanese Unexamined Patent Application Publication No. 148170/1983) in which this method is used. However, although the nozzle portion requires highly precise machinability, it is extremely difficult to obtain a material that is highly water repellent and has high precision machinability.

(Object of the Invention) The object of the present invention relates to strict requirements for the ink wetting characteristics of the nozzle portion of the recording head, especially the surface where the ejection ports are formed, and various problems related to these requirements. The object of the present invention is to provide a recording head in an inkjet recording apparatus in which the surface on which ink jet ports are formed has high water repellency and is chemically and mechanically durable.

A second object of the present invention is to provide a recording head having an ink ejecting orifice which can be processed easily and with high precision.

(Structure of the Invention) It is an object of the present invention to form an amorphous material mainly composed of silicon and carbon on the surface where ink ejection ports are formed in the recording head that ejects ink of an inkjet recording device. This can be achieved by a recording head characterized by being provided with a water-repellent layer consisting of:

In the most preferred embodiment of the present invention, the surface of the recording head on which ink ejection holes are formed contains amorphous silicon carbide, preferably fluorine, and more preferably hydrogen. Silicon carbide (
a-8i, z CX :H,F).

It is already well known that crystalline silicon carbide (S1c) can withstand high temperatures of 2000°C or higher, has excellent acid and alkali resistance, and has high hardness and mechanical strength. A convenient method for producing amorphous silicon carbide is described in the Philosophical Magazine regarding its production method by glow discharge.
Magazine) Volume 35 (1977), and the high frequency sputtering method is described in Thin Solids Films Volume 2 (1968).

The present invention focuses on the above-mentioned excellent heat resistance, chemical stability, and mechanical toughness of amorphous silicon carbide, as well as workability, and makes it possible to easily and accurately vacuum amorphous silicon carbide after forming a recording head on the surface where the injection ports are formed. A water-repellent surface layer is formed by a glow discharge method, a sputtering method, etc., and more preferably hydrogen is added to the water-repellent layer to impart chemical and physical stability over time. Furthermore, by adding fluorine to the composition, the heat resistance, chemical stability, and water repellency are increased (improved).Crystalline StC has excellent heat resistance, chemical stability, and mechanical strength. (Although it is known and as mentioned above, the amorphous silicon carbide used in the present invention also has these excellent properties, and moreover, the ink jet orifices are formed at the tip of the recording head, that is, at the recording head.) It can be formed as a thin film layer on the recording surface. This also shows that amorphous silicon carbide is suitable as the water repellent layer of the recording head.Furthermore, the recording head is generally formed of silicate glass. However, amorphous silicon carbide has good adhesion to this head forming material,
A strong water-repellent layer is formed.

In the amorphous silicon carbide mainly composed of carbon and silicon according to the present invention, the content of carbon is 5 to 50 atomic %, and the hydrogen content is 1 to 40 atomic %, preferably 5 to 30 atomic %. The amount of fluorine contained is 0.01 to 20 at%, preferably 0.1
~10 at%.

Furthermore, the term "amorphous" refers to a state in which no crystalline portions exist throughout the material, or a state in which partially microcrystalline regions are scattered throughout the material.

The thickness of the water-repellent layer to be formed is 0.2 to 30 μm, preferably 0.5 to 10 μm.

When forming, at least the lip is exposed in a vacuum furnace, and a recording head is installed with a rotating mechanism or the like conveniently installed for uniform formation, and the inside of the vacuum furnace is maintained at an appropriate degree of vacuum, using a vacuum evaporation method. It is formed by controlling the composition ratio of silicon and carbon and the content of hydrogen and fluorine by a glow discharge method, a sputtering method, an ion plating method, or the like.

Taking the glow discharge method as an example, silane or silane derivative gas (e.g. SiH4,812Ha, 5iCJ4.5i
n(4, SIH, C/ffi, SiF, 5i(CH8
), etc.), or the gas is converted to B7 or He, Ne
gas diluted with an inert gas such as organic gas (e.g. C
H4, C, H,, C, H4, C! H6,C3l(4,C
, H6, C, H, etc.) or fluorine-based gas (e.g. CF, etc.)
CH3F, C,H3P, C,H3P,,C5F,,
C,CIF,,CCA',F.

At least one type of gas such as F, , HF, BrF3, etc.) is introduced into a glow discharge vacuum furnace, a glow discharge is induced by high frequency or direct current, the introduced gas is decomposed, and it adheres to the exposed lip part. to form a film.

Furthermore, if the sputter link method is used, a target material with a predetermined composition ratio of silicon and carbon, or a target material containing only silicon and carbon, is hit with an accelerating inert gas, etc., and the target material is knocked out by the impact. What is necessary is to cause the substance to react with hydrogen gas or fluorine gas to form an amorphous film on the exposed lip of the injection port.

Regarding the ion plating method and the vacuum deposition method, it is possible to form an amorphous water-repellent layer on the lips using techniques that have already been put into practical use.

The amount of hydrogen and fluorine contained in the amorphous water-repellent layer according to the present invention may be controlled by controlling the amount of hydrogen-containing and fluorine-containing substances introduced into the vacuum furnace. A method of implanting a predetermined amount of hydrogen or fluorine into silicon may also be used. Alternatively, a method may be used in which the amorphous silicon carbide film is exposed to the activated gas atmosphere under predetermined conditions.

Next, the vacuum furnace device used in the present invention will be explained by giving an example. As an example, FIG. 1 shows an apparatus using the glow discharge method. In the vacuum pelger 2 of the glow discharge vacuum furnace 1,
A holding member 4 of a recording head 5 is provided facing the glow discharge electrode 3 and the electrode 3 at a predetermined distance above the electrode. A large number of recording heads 5, 5', etc. can be placed on the holding member 4, and it is also horizontally rotatable. Further, a heating member 4' is placed side by side when necessary. Glow discharge electrode 3 is a high frequency power source 6
A glow discharge is generated between the glow discharge electrode 3 and the holding member 40 by applying high frequency power.

A gas introduction pipe is connected to the vacuum perger 2,
Flowmeters G3, G2, G, and G4, etc. bent to gas cylinders B1, B3, B3, and B2, respectively, and flow rate adjusting pulps (for example, needle pulp) ■1, ■1, ■, and V.

The flow rate of the specified gas is adjusted through the vacuum Pelger 2.
will be introduced in Further, a filter 7 removes dust in the gas, and a pulp 8 is provided for comprehensive flow rate adjustment. An evacuation device (not shown) is operated at the lower part of the vacuum pelger 2 via a diffusion pump pulp 9 and a tetragonal pump valve 10 to maintain the degree of vacuum in the vacuum pelger 2 at a predetermined level.

In order to form a water-repellent layer consisting of &-81t-xcx: H and F on the lip of the injection port of the recording head 5 in the glow discharge vacuum furnace 1, first, the surface of the recording head 5 is physically and chemically treated. Clean it, place it on the holding member 4, and fix it. Next, the pressure inside the vacuum pelger 2 is reduced using an exhaust device, preferably to 10
torr or less, and if necessary, the recording head 5 and the like are brought to a predetermined temperature, the diffusion pump pulp 9 is closed, and the rotary pump alone is used to exhaust air to a predetermined back pressure. Next, the gases necessary for forming the water-repellent layer are introduced from the gas cylinders B3 and the like by adjusting the flow rates using the respective flow rate adjusting pulps η and the like while monitoring with the attached flowmeters G1 and the like.

Here, for example, gas cylinder B is filled with silane gas, silane derivative gas, or diluent gas, B is filled with an organic gas such as the carbon compound mentioned above, hydrogen gas is used as a bird, and raw material such as fluorine gas is filled in B4. Filled with gas. These source gases may be mixed in advance at a predetermined mixing ratio.

The raw material gas is caused to flow between the glow discharge electrode 3 and the holding member 4, and then regulated by the rotary pump pulp 10 to bring the inside of the vacuum pelger 2 to a degree of vacuum of 10-2 to 10 torr. Next, high frequency chamber pressure is applied from the high frequency power source 6 to generate glow discharge between the glow discharge electrodes 3 and the holding member 4.

The appropriate frequency of the applied high-frequency voltage is about 0.1 MHg, and not only AC voltage but also DC voltage of 0.3 to 5 KV may be used. Furthermore, the glow discharge vacuum furnace 1 may be of the capacitive coupling type described above, or may be of the inductive coupling type using coiled glow discharge electrodes.

When using the sputtering method, a vacuum Pelger 2 similar to that shown in FIG. 1 is used as a sputtering furnace, and a target material having a predetermined composition ratio is placed at the glow discharge electrode 3 shown in the same figure. , high frequency or direct current sputtering may be performed toward the recording head 5 etc. placed on the holding member 4. Further, in order to incorporate a predetermined amount of hydrogen or fluorine into the amorphous film to be formed, the doping gas such as hydrogen or fluorine may be adjusted to a predetermined partial pressure and introduced into the vacuum Pelger as in the case of glow discharge. .

In the present invention, when forming a water-repellent layer in a vacuum pelger, the temperature at the lip of the ejection opening of the recording head is (3) to 350°C.
, preferably 100 to 300°C, and the formation rate of the layer is preferably in the range of 0.5 to 50λ/Bee.

(Example) Next, the present invention will be specifically explained with reference to Examples.

Example-1 In the capacitively coupled glow discharge vacuum furnace 1 shown in FIG.
As shown in the figure, substrates 10a, 1 made of silicate glass
The amorphous water-repellent layer according to the present invention was provided on the surface 13 where the ink jet orifices of the recording head were formed, and had the jet nozzles 11, the jet orifices 12, and the surface 13 where the ink jet orifices were formed. The conditions for preparing the water-repellent layer are as follows.

(Introduced gas) SiL: Diluted to 10.7% with Ar Flow rate 2 c, c, / 5ec CF4: Partial pressure ratio with 5IH4 CF4/S 1H4 = 1/1 (Vacuum Pelger back pressure): I X 10-'
torr (degree of vacuum during discharge): 0.5 torr (
High frequency 1 civil power): 13.6MHg, 70W (0
, 29W/m7) (distance between poles): 2.5cm (recording head temperature): approximately 200°C (formation speed): approximately 5λ/see Under the above conditions, the ejection opening lip portion 1 of the recording head shown in FIG.
3 was provided with a 1.8 micron thick water repellent layer.

According to Augor analysis, C/Sl = 0.
It is 26.

Regarding the recording head of the present invention prepared as described above, the untreated one, and the three types of recording heads in which a fluorine-based coating agent was applied to the lip portion 13 to form a water-repellent layer, (a) ink resistance and (b) The injection performance was compared.

The ink used was 40 wt% polyhydric alcohol.
- It is an aqueous ink containing 8 wt% of the material and has a pH of 11.5.

(a) Ink resistance: immersing the lips of the three types of recording heads in the ink;
As a result of an endurance test conducted at ω°C for several days, it was found that the recording head of the present invention exhibited the same water repellency as before the test without any deterioration; however, in the two comparative recording heads, The initial water repellency was lost and significant wetting occurred.

(b) Jetting Performance The three types of recording heads described above were mounted on an on-demand type inkjet writing device, and long-term continuous jetting and intermittent jetting tests were conducted under practical conditions. The results are shown in Table 1.

Table 1: In intermittent injection, the lip is closed with a cap each time, so generally a ring is formed around the lip or the injection port due to the cap or attached foreign matter, so the mechanical strength of this part is an additional factor in the result. . Variations in ejection volume are also due to variations in ink droplet size.

The intermittent jetting was performed 5,000 times with 10 second jet and second second pause, and no abnormality occurred in the recording head of the present invention during this period.

Example 2 An amorphous water-repellent cup according to the present invention was formed on the lip of the recording head made of the glass shown in FIG. The layer thickness is 2.0 microns.

The preparation conditions are as follows.

(Introduced gas partial pressure ratio); Ar:H2:CF4=70:
25: 5 (temporary sputtering vacuum degree), 10 to
rr (high frequency power); 13MHg, 500W (
1.6 w/ffl) (recording head temperature); ~200°C (formation speed); approximately 2λ/sec The layer thus obtained has an Auger analysis result C/
The S i2 was 0.15.

The recording head improved as described above had the same performance as the recording head according to the present invention obtained in Example 1, and stable recording was always possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a glow discharge vacuum furnace used in the present invention. FIG. 2 is a sectional view of the tip of the ejecting orifice of one example of the recording head of the present invention. 1...Glow discharge vacuum furnace, 2...Vacuum bell jar,...
3...Glow discharge electrode, 4...Holding member-5...
Recording head, 11... Ejection nozzle, 12... Injection port, 13... Lip portion. Agent Yoshimi Kuwabara Procedural Amendment 1981 7>] 27 l11 1 ・1f I11 lshi 1988 special f+' Wi No. 16756 υ2 Invention name recording head: 7 Supplement 11 Relationship with the famous case Patent applicant address: 1-26-21 Nishi-Shinjuku, Shinjuku-ku, Tokyo
Name (1271 Konishiroku Photography Co., Ltd. Representative Director Nobuhiko Kawamoto 4th generation pH Person: 191 Address 1, Sakura-cho, 11th F City, Tokyo!!: Location 6 within Konishiroku Photography Co., Ltd. 6, subject to correction "Column for detailed explanation of the invention in the specification" 7. Contents of the amendment Specification box page 15, line 5 "0.I MHPJ" [o, IMHZ J and correction O, page 17, line 3 " ta, 6yrmff J, r13.6MHz
Corrected with J. Page 19, line 16, "13MHf-J" has been corrected to "13MHz."

Claims (4)

[Claims] (1) A water-repellent layer made of an amorphous material mainly composed of silicon and carbon is provided on the surface of the recording head that jets ink of the inkjet recording device, on which the ink jet ports are formed. To the record, de. (2) The recording head according to claim 1, wherein the amorphous material forming the water-repellent layer contains fluorine. (3) The recording head according to claim 1 or 2, wherein the amorphous material forming the water-repellent layer contains hydrogen. (4) Claim 1, wherein the amorphous material forming the water-repellent layer has a carbon content of 5 to 50 atomic %;
Go to the record described in paragraph 2 or 3.