JP2826515B2 - Electrostatic ink jet recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic ink jet recording head, and more particularly to an electrostatic ink jet recording head which performs recording by attaching toner particles to a recording medium.

[0002]

2. Description of the Related Art The non-impact recording method has recently attracted attention in that noise during recording is extremely small to a negligible level. Among them, the ink jet recording method that can directly perform high-speed recording on a recording medium with a simple mechanism and that can perform recording on plain paper is an extremely powerful recording method, and various methods have been proposed so far. ing.

In this method, a voltage is applied between an electrode provided on the back surface of a recording paper and a needle electrode facing the recording paper, and a color material such as ink is caused to fly by an electrostatic force of the generated electric field, thereby performing recording. There is.

FIG. 7 shows, for example, Japanese Patent Application No. 07-236276.
FIG. 8 is a perspective view showing a first example of this conventional ink jet recording head shown in the specification, and FIG. 8 is a cross-sectional view and a top view of a head end portion of the ink jet recording head. A first example of this conventional ink jet recording method will be described with reference to FIGS. The substrate 21 is an insulator such as glass, and has a plurality of recording electrodes 2 on its surface.
2 are formed. The recording electrode 22 is formed by patterning a conductive material such as chrome sputtered on the entire surface of the substrate by photolithography.
nch) pitch, that is, at intervals of about 85 μm. The recording electrode 22 is connected to a driver (not shown), and can selectively apply a high voltage pulse to the recording electrode 22 during recording.

The meniscus forming member 23 is formed by processing a photosensitive polymer film laminated on the substrate 21 by photolithography. The meniscus forming member 23 is formed at a position slightly receded from the leading end of the recording electrode so as to overlap each recording electrode 22. ing. The thickness of the photosensitive polymer film is 30 μm, and the width of the meniscus forming member 23 is about 30 μm. A cover 24 is mounted on the meniscus forming member 23 at a position further retracted from the tip of the meniscus forming member 23. The cover 24 is an insulating member, and the ink supply port 25 and the ink discharge port 26 are processed in advance.
The substrate 21 and the cover 24 are slit-shaped ink jet ports 2
7 and the recording electrode 22 is provided outside the ink jetting port 27.
The meniscus forming member 23 on top protrudes. The meniscus forming member 23 also has a purpose of supporting the cover 24, and therefore partially extends below the cover 24. Further, when the meniscus forming member 23 is formed, a continuous wall surface is simultaneously formed on the head side portion and the rear end portion, and the substrate 21 and the cover 24 constitute an ink chamber.

FIG. 9 shows, for example, Japanese Patent Application No. 08-012897.
FIG. 5 is a perspective view showing a second example of a conventional electrostatic ink jet recording head shown in the specification. Referring to FIG. 9, the substrate 31 is an insulator such as plastic, and supports the base film 40 from the back side. The base film 40 is an insulator such as polyimide and has a thickness of 5
A plurality of recording electrodes 32 are integrally formed on the surface thereof. The recording electrodes 32 are formed by pattern-plating a conductive material such as copper on the base film 40 to a thickness of 20 to 30 μm, and are arranged at a pitch of 300 dpi, that is, at intervals of about 85 μm. In addition, the recording electrode 3
2 independently project from the end face of the base film 40, and the projection amount is 80 μm to 500 μm.
It is about. Further, the surface of the recording electrode 32 is uniformly covered with an insulating coating member 33 with a thickness of 10 μm or less.

[0007] This conventional electrostatic ink jet recording head uses a tape-shaped head in which recording electrodes 32 are integrally formed on a base film 40.
A TAB tape used in apeAutomated Bonding (TAB) technology is used, and an insulating coating member 33 is formed by chemical vapor deposition of parylene resin.

The recording electrode 32 is provided on the base film 40.
The cover 34 is attached at a position that does not cover the protruding portion. The cover 34 is an insulating member, and the ink supply port 35 and the ink discharge port (not shown) are processed in advance. The space defined by the base film 40 and the cover 34 forms an ink chamber. It is filled from the ink supply port 35 and is filled inside. Further, the cover 34 has an opening at the tip, and the base film 4
The slit-shaped opening formed by the cover 0 and the cover 34 forms an ink ejection port 37, in which an ink meniscus is formed. An electrophoresis electrode 41 that is in contact with the ink 36 is formed inside the cover 34. The migration electrode 41
A voltage having the same polarity as the potential of the toner is applied, and the toner particles in the ink 36 supplied from the ink supply port 35 are separated by the electric field between the migrating electrode 41 and a counter electrode (not shown).
It is transported to the vicinity of 2 by the electrophoresis phenomenon.

FIG. 10 is an enlarged view (FIG. 10) of the vicinity of the ink ejection port 37 (portion A) of the conventional electrostatic ink jet recording head in a state where ink is supplied.
(A)) and AA cross section (FIG. 10 (b)) are shown. Referring to FIG. 10 in conjunction with FIG. 9, the ink 36 is applied to the ink ejection port 37 by the surface tension of the ink meniscus 38.
To form Since a negative pressure is applied to the ink 36 in the head and the recording electrode 32 protrudes from the base film 40 and the cover 34, the ink meniscus 38 has a concave shape obliquely downward when viewed from the side. Furthermore, since each recording electrode 32 individually protrudes outside the ink ejection port 37, an ink meniscus 38 is formed corresponding to each recording electrode 32 when viewed from above. For this reason,
When a high voltage pulse is applied to an arbitrary recording electrode 32, an electric field is concentrated on the tip of the ink meniscus 38 protruding from the recording electrode 32. The charged toner in the ink 36 is guided by this electric field, is drawn out from the tip end of the protruding ink meniscus 38, and forms a toner group 39. To fly. The toner adhering to the printing paper and forming the recording dots is heated and fixed by the heater.

[0010]

However, the first problem in the first example of the above-mentioned conventional ink jet recording head is that stable ejection cannot be performed only from the ejection point. The reason is that the meniscus forming member forming the discharge point is formed on the substrate and formed in a state offset from the substrate end to the back, so that the meniscus overflows from the meniscus holding member for some reason, This is because it becomes possible to reach the end of the substrate. This is because if a drive pulse is applied to the recording electrode in that state, the toner particles fly from any part of the substrate edge.

A second problem is that the head cost is high. The reason is that the manufacturing process is complicated because a head is manufactured on a substrate by a thin film forming technique (photolithography).

A first problem in the above-described second example of the conventional ink jet recording head is that stable ejection cannot be performed due to bending of a recording electrode of the recording head or the like. The reason is that the recording electrode is discharged from the base film, so that the strength is weak.

A second problem is that toner particles tend to accumulate between the recording electrode and the base film. The reason is that, since the leading end of the base film is located at a position retracted from the leading end of the recording electrode, there is no ink flow in that portion.

A third problem is that the meniscus is not stable at the tip of the discharge section. The reason is that the meniscus is formed only between the recording electrodes, so that the meniscus fluctuates due to pressure fluctuation or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-element, low-cost, and reliable electrostatic ink jet recording head for discharging only toner particles in ink by an electrostatic field. The purpose is to provide a head.

[0016]

According to the present invention, there is provided an electrostatic ink jet recording head comprising: a base film having an insulating property; and one surface of the base film, one end of which protrudes from the end of the base film. An electrostatic ink jet recording head further comprising a plurality of recording electrodes the surfaces of which are coated with an insulating coating material, and an upper cover formed on the recording electrode surface and holding ink containing toner particles therein. In this case, the base film is characterized in that a tip portion is divided into a plurality at positions corresponding to the recording electrodes.

Further, in the electrostatic ink jet recording head according to the present invention, a cross section of a tip portion of the base film divided into a plurality at positions corresponding to the recording electrodes is tapered.

Further, in the electrostatic ink jet recording head according to the present invention, a flat surface of a tip portion of the base film divided into a plurality at positions corresponding to the recording electrodes is tapered.

Further, in the electrostatic ink jet recording head according to the present invention, the leading end of the base film divided into a plurality at positions corresponding to the recording electrodes is constituted at least up to the leading end of the recording electrode. It is characterized by.

Further, in the electrostatic ink jet recording head according to the present invention, the upper cover is in close contact with the recording electrode in the vicinity of the recording electrode, and the ink flows between the plurality of recording electrodes.

Further, in the electrostatic ink jet recording head of the present invention, the insulating base film and the recording electrodes are integrally formed on a two-layer or three-layer tape used in Tape Automated Bonding technology. It is characterized by being.

[0022]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an electrostatic ink jet recording head according to one embodiment of the present invention. FIG. 2 is an enlarged view (FIG. 2 (a)) and an AA cross-sectional view (FIG. 2 (b)) of the vicinity of the ink ejection port 7 when ink is supplied in the ink jet recording head of this embodiment, as viewed from above. Is shown.

Referring to FIGS. 1 and 2, the substrate 1 is an insulator such as plastic and supports the base film 10 from the back side. The base film 10 is an insulator such as polyimide, has a thickness of about 50 μm, and has a plurality of recording electrodes 2 formed integrally on the surface thereof. The recording electrode 2 is formed by pattern-plating a conductive material such as copper on the base film 10 to a thickness of 20 to 30 μm, and has a pitch of 300 dpi, that is, about 85 μm.
They are arranged at intervals. Further, the recording electrodes 2 protrude independently from the end faces of the base film 10, respectively.
The protrusion amount is about 80 μm to 500 μm. Further, the surface of the recording electrode 2 is uniformly covered with an insulating coating member 3 with a thickness of 10 μm or less. In the recording head of this embodiment, a tape-shaped head in which the recording electrodes 2 are integrally formed on the base film 10 is used. Specifically, a TAB tape used in Tape Automated Bonding (TAB) technology is used. Further, the insulating coating member 3 is formed by chemical vapor deposition of parylene resin.

On the base film 10, the recording electrodes 2
The cover 4 is attached to a position where the cover 4 is not covered. The cover 4 is an insulating member, and the ink supply port 5 and the ink discharge port (not shown) are processed in advance.
The space formed by the base film 10 and the cover 4 forms an ink chamber, and the ink is filled from the ink supply port 5 to fill the inside. Further, the cover 4 has an opening at the tip, and the base film 10 and the cover 4
The slit-shaped opening formed by the above forms an ink ejection port 7, and an ink meniscus 8 is formed therein.
Inside the cover 4, a migration electrode 11 contacted with ink is provided.
Is configured. A voltage having the same polarity as the potential of the toner is applied to the migration electrode 11, and the toner particles in the ink supplied from the ink supply port 5 are brought into the vicinity of the recording electrode 2 by an electric field between the migration electrode 11 and a counter electrode (not shown). It is transported by the electrophoresis phenomenon.

The ink jet recording head of this embodiment is connected to an ink tank (not shown) by a tube, applies a negative pressure of about 1 cmH ₂ O, and forcibly circulates ink. The ink is obtained by dispersing fine particles of a thermoplastic resin, a so-called toner, which is colored together with a charge control agent in a petroleum organic solvent (isoparaffin), and the toner is apparently charged to a positive polarity by a zeta potential.

In order to reinforce the strength of the recording electrode 2, the base film 10 has a support taper 17 so as to assist a part of the bottom of the base of each recording electrode 2 which is protruded from the base film 10. Have. The ink forms an ink meniscus 8 at the ink ejection port 7 due to its surface tension. A negative pressure is applied to the ink in the head, and the recording electrode 2 is connected to the base film 10.
Since the ink meniscus 8 projects from the cover 4, the ink meniscus 8 has a concave shape obliquely downward when viewed from the side. Further, since each recording electrode 2 individually protrudes outside the ink ejection port 7, the ink meniscus 8 is formed corresponding to each recording electrode 2 when viewed from above.

Therefore, when a high voltage pulse is applied to an arbitrary recording electrode 2, an electric field is concentrated on the tip of the ink meniscus protruding from the recording electrode 2. The charged toner in the ink is guided by this electric field, drawn out from the tip of the protruding ink meniscus, and forms a toner group 9 and flies in the direction of the recording paper, not shown, facing the recording head. . The toner adhering to the recording paper and forming the recording dots is heated by a heater and fixed.

FIG. 3 is a schematic view of a TAB tape used in the electrostatic ink jet recording head of the present invention. TA
A method for manufacturing the B tape 12 will be schematically described. Flash plating is performed on a tape-like base film 10 such as polyimide having sprocket holes 15 at both ends.
Next, a dry film is laminated, and a pattern is formed by exposure and development. Thereafter, the base film 10 is etched by pattern plating with copper or the like, and the through holes 14 are formed. Thereafter, the resist film is removed and finish plating is performed. Thereafter, an insulating coating member is chemically vapor-deposited where necessary, and used as a recording head.
In this process, the inner lead portion 13 protruding from the portion where the base film 10 is removed by etching.
Becomes the recording electrode 2.

FIG. 4 is a top view showing another embodiment of the present invention. Referring to FIG.
Constitutes a support taper portion 17 in a plane to reinforce the strength of the recording electrode 2.

FIG. 5 is a sectional view showing still another embodiment of the present invention. In order to reinforce the strength of the recording electrode 2, the base film 10 has a support taper portion 17 so as to assist the bottom of a part of the root of each recording electrode 2 which is protruded from the base film 10. I have.
Therefore, the ink forms an ink meniscus 8 at the ink ejection port 7 due to its surface tension, and also forms an ink meniscus 8 between the recording electrode 2 and the support taper portion 17. For this reason, when a high-voltage pulse is applied to an arbitrary recording electrode 2, the projecting support taper portion 17
The electric field is concentrated at the tip of the ink meniscus. The charged toner in the ink is guided by this electric field and is drawn out from the protruding tip end of the ink meniscus, and the toner group 9
Then, it flies in the direction of the recording paper, that is, the counter electrode (not shown) facing the recording head.

FIG. 6 shows an ink ejection port 7 of a recording head according to still another embodiment of the present invention in a state where ink is supplied.
It is the enlarged view which looked at the vicinity from the upper surface (FIG. 6A), the AA sectional view (FIG. 6B), and the BB sectional view (FIG. 6C). The cover 4 is attached on the base film 10 at a position not covering the protruding portion of the recording electrode 2.
The cover 4 is an insulative member, and has an ink supply port 5 in advance.
In addition, an ink discharge port (not shown) is processed, and a space defined by the base film 10 and the cover 4 forms an ink chamber, and the ink is filled from the ink supply port 5 and filled therein. Further, the cover 4 has a configuration in which the front end thereof is not particularly opened, and the cover 4 is in close contact with the base film 10. Base film 10
The pattern of the upper recording electrode 2 has a thickness of 20 to 30 μm.
m, the space between the portion where the pattern of the recording electrode 2 has no pattern and the cover 4 forms the ink flow path 16. The slit-shaped opening forms an ink ejection port 7, and an ink meniscus is formed therein. That is, the cover 4
The ink flow path 16 and the ink ejection port 7 are formed without specially processing the tip of the ink jet head.

[0033]

The first effect is that stable ejection can be performed only from the ejection point. The reason is,
This is because the recording electrode is formed by coating the TAB inner lead with an insulating coating, and the leading end thereof is used as a discharge point. Since the recording electrode exists independently of each other, a meniscus is always formed at each discharge point.

The second effect is that the head cost is low. The reason for this is that the recording electrode portion of the head is made of a tape used for TAB and the inner lead of the tape is coated with an insulating material.

The third effect is that the strength of the recording electrode is increased, the electrode is not bent, and stable ejection can be performed. The reason for this is that the inner lead portion of the TAB tape is coated with an insulating coating to form a recording electrode, and the recording electrode is supported from the bottom by the TAB tape.

A fourth effect is that the toner particles flow smoothly near the recording electrode. The reason is that the toner particles do not accumulate between the base film and the recording electrode because the tip of the base film protrudes from the recording electrode tip.

The fifth effect is that the meniscus is always stable at the tip of the discharge section. The reason is that the meniscus is held even in the tapered portion of the base film formed between the recording electrodes, and is therefore strong against disturbance due to pressure fluctuation or the like.

[0038]

[Brief description of the drawings]

FIG. 1 is a perspective view of an electrostatic ink jet recording head according to an embodiment of the present invention.

FIG. 2 is an enlarged view (FIG. 2 (a)) and a cross-sectional view taken along the line AA of an ink jet recording head of the embodiment of FIG.
(B)).

FIG. 3 is a schematic view of a TAB tape used in the electrostatic ink jet recording head of the present invention.

FIG. 4 is a top view of an electrostatic ink jet recording head according to another embodiment of the present invention.

FIG. 5 is a sectional view of an electrostatic ink jet recording head according to still another embodiment of the present invention.

FIG. 6 is an enlarged view (FIG. 6 (a)) and an AA cross section of the vicinity of an ink ejection port when ink is supplied in an electrostatic ink jet recording head according to still another embodiment of the present invention, as viewed from above. (FIG. 6B) and BB cross-sectional view (FIG.
(C)).

FIG. 7 is a perspective view of a conventional electrostatic ink jet recording head.

FIG. 8 is a top view (FIG. 8A) and a cross-sectional view (FIG. 8) of a head end portion of a conventional electrostatic ink jet recording head.
(B)).

FIG. 9 is a perspective view of still another conventional electrostatic ink jet recording head.

FIG. 10 is a top view (FIG. 10 (a)) and a cross-sectional view (FIG. 10 (b)) of the head end of another conventional electrostatic ink jet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording electrode 3 Insulating coating member 4 Cover 5 Ink supply port 7 Ink ejection port 8 Ink meniscus 9 Toner group 10 Base film 11 Migration electrode 12 TAB tape 13 Inner lead part 14 Through hole 15 Sprocket hole 16 Ink channel 17 Support taper

Continuing on the front page (72) Ryosuke Agematsu 7546 Yasuda, Kashiwazaki-shi, Niigata Prefecture Niigata Nippon Electric Co., Ltd. (72) Inventor Hitoshi Minemoto 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. 72) Inventor Toru Yakushiji 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (72) Inventor Tadashi Mizoguchi 7546 Yasuda, Oji, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (72) Inventor Hito Takemoto Tsukasa 7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Nippon Electric Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/06

Claims (6)

(57) [Claims] 1. A base film having an insulating property, and a plurality of base films formed on one surface of the base film, one end of which is formed to protrude from an end of the base film, and the surfaces of which are further coated with an insulating coating material. In an electrostatic ink jet recording head having a recording electrode and an upper cover formed on the recording electrode surface and holding ink containing toner particles therein, the base film has a leading end portion for each of the recording films. An electrostatic ink jet recording head which is separated into a plurality at positions corresponding to the electrodes. 2. The electrostatic ink jet recording head according to claim 1, wherein a cross section of a tip portion of the base film divided into a plurality at positions corresponding to the recording electrodes has a tapered shape. 3. The electrostatic ink jet recording head according to claim 1, wherein a flat surface of a tip portion of the base film divided into a plurality at positions corresponding to the recording electrodes has a tapered shape. . 4. The recording medium according to claim 1, wherein a front end portion of the base film divided into a plurality of portions at a position corresponding to the recording electrode is configured to at least a front end portion of the recording electrode. The electrostatic ink jet recording head according to the above. 5. The static electricity according to claim 1, wherein the upper cover is in close contact with the recording electrodes, and the ink flows between the plurality of recording electrodes. Electric inkjet recording head. 6. The recording medium according to claim 1, wherein the insulating base film and the recording electrodes are integrally formed on a two-layer tape or a three-layer tape used in a tape automated bonding technique. 5. The electrostatic ink jet recording head according to claim 3, 3 or 4.