JP2826529B2 - 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 flying toner particles by electrostatic force using ink in which toner particles are dispersed in a carrier liquid. About.

[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. 9 shows, for example, Japanese Patent Application No. 07-120252.
FIG. 10 is a perspective view showing an example of this conventional ink jet recording head shown in the specification, and FIG. 10 is a plan view of the head end portion of the ink jet recording head and AA
It is sectional drawing.

[0005] This conventional ink jet recording head will be described with reference to FIGS. 9 and 10. The substrate 21 is an insulator such as glass, and a plurality of recording electrodes 22 are formed on the surface thereof. The recording electrodes 22 are formed by patterning a conductive material such as chromium sputtered on the entire surface of the substrate by photolithography, and are arranged, for example, at a pitch of 300 dpi (dots per inch), 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, and is formed at a position slightly receded from the leading end of the recording electrode 22 so as to overlap each recording electrode 22. Have been. 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 form a slit-shaped ink ejection port 27, and a meniscus forming member 23 riding on the recording electrode 22 protrudes outside the ink ejection port 27. 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.

Further, in order to concentrate the toner particles in the ink and supply it to the vicinity of the ink ejection port 27 through the ink flow path, an electrophoretic electrode 30 is provided behind the ink flow path. Due to the electric field between the migrating electrode 30 and the electrode provided on the back of the recording paper, the toner particles in the ink move by the electrophoretic force and concentrate near the ink ejection port 27.

[0009]

However, the above-described conventional electrostatic ink jet recording head described above is obtained by patterning a conductive material such as chromium obtained by sputtering a plurality of recording electrodes over the entire surface of a substrate by photolithography. ,
Since the meniscus forming member is obtained by processing a photosensitive polymer film laminated on a substrate by photolithography, there is a problem that the manufacturing process of the head is complicated and the cost of the head cannot be reduced.

Furthermore, since the meniscus forming member is formed of a photosensitive polymer film, there is a problem that the thickness of the meniscus forming member is limited by the thickness of the film and the amount of ink supply is limited.

Further, since the toner particles are supplied to the ink ejection port only by the electrophoretic force of the toner by the electrophoretic electrode, there is a problem that it is difficult to always supply a proper toner.

Further, when the ink is not driven, the ink meniscus is settled at a position slightly retreated from the tip of the meniscus forming member, so that a time lag occurs before the ink is ejected when a high voltage driving pulse is applied. There is.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reliable and low-cost apparatus that always supplies a proper toner and stably supplies toner particles to an ejection point. An object of the present invention is to provide an electrostatic ink jet recording head which discharges only toner particles in ink by an electrostatic field, which is a multi-element head.

[0014]

According to the present invention, there is provided an electrostatic ink jet recording head comprising: a base film having an insulating property; a slit-shaped opening formed in a part of the base film; A plurality of recording electrodes which are formed so as to face each other to the slit-shaped opening and project on the surface of the protrusion with an insulating coating member, and the base film is bent at the slit-shaped opening. And a holding member for holding.

Further, the electrostatic ink jet recording head of the present invention is characterized in that a driving pulse is applied to each of the recording electrodes formed facing each other.

Further, in the electrostatic ink jet recording head according to the present invention, the interval between the front ends of the recording electrodes formed to face each other is an integral multiple of the pitch of the recording electrodes.

Further, in the electrostatic ink jet recording head according to the present invention, the recording electrodes are formed so as to face each other in a staggered arrangement.

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 having.

Further, the electrostatic ink jet recording head of the present invention is characterized in that the electrostatic ink jet recording head is provided with an electrophoretic electrode configured to be in contact with ink containing toner particles flowing between the base film and the holding member. .

[0020]

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, and FIG. 2 is a view of the head end of the ink jet recording head of this embodiment viewed from the direction of arrow A in FIG. FIG. 3 is a front view, FIG. 3 is a cross-sectional view of the head end of the ink-jet recording head of this embodiment, and FIG. .

Referring to FIGS. 1, 2 and 3, an electrostatic ink jet recording head of this embodiment includes a base film 10 having an insulating property and a base film 1 having an insulating property.
0, and a slit-shaped opening 19 formed on the surface of the base film 10.
A plurality of recording electrodes 2 which are formed so as to protrude partly facing each other and whose surface is covered with an insulating coating member 17, and a holding member 20 which bends and holds the base film 10 by slit-shaped openings 19. And an electrophoresis electrode 11 configured to be in contact with ink containing toner particles flowing between the base film 10 and the holding member 20.

The holding member 20 is made of an insulator such as plastic and has sharp corners.
0 is supported from behind. Base film 1
Numeral 0 denotes an insulator such as polyimide, the thickness of which is about 50 μm. Further, the base film 10 is
It has a slit-shaped opening 19 opened at the position of the 0 corner, and a plurality of recording electrodes 2 are integrally formed on the surface thereof so as to face the slit-shaped opening 19.

The recording electrodes 2 are formed by pattern-plating a conductive material such as copper on the base film 10 to a thickness of 20 to 30 μm, and are arranged, for example, at a pitch of 300 dpi, that is, at intervals of about 85 μm. Also, the recording electrode 2
The surface of the portion exposed to the slit opening 19 is uniformly covered with the insulating coating member 17 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.
TAB tape used for onding (TAB) technology is used. The insulating coating member 17 is formed by chemical vapor deposition of a parylene resin.

The holding member 20 is an insulating member, and the ink supply port 5 and the ink discharge port 6 are respectively processed in advance. The space below the slit opening 19 constituted by the base film 10 and the holding member 20 constitutes an ink chamber. The ink flows from the ink supply port 5 through the ink chamber to the ink discharge port 6 through the ink flow path 16 formed in the holding member 20.

The recording head of this embodiment is connected to an ink tank (not shown) by a tube.
A negative pressure of about mH ₂ O is applied, and ink is forcibly circulated. 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.

A pair of recording electrodes 2 disposed opposite to each other
One of the two recording electrodes is an electrode to which a driving voltage is applied.
The other recording electrode 2 is configured to independently hold the ink meniscus 8 on each of the opposing recording electrodes 2. Therefore, the ink forms an ink meniscus 8 between the recording electrodes 2 formed facing the slit-shaped opening 19 and on the upper surface of the recording electrode 2 as shown in FIG. This is because a negative pressure is applied to the ink in the recording head, and the ink is an ink flow 21 having a certain flow velocity.
Is in the slit opening 19 and protrudes from the base film 10 or the like.

The migrating electrode 11 that is brought into contact with the ink in the ink flow path just below the slit-shaped opening 19 between the holding member 20 and the base film 10 is configured to cross the plurality of recording electrodes 2. I have. The electrophoresis electrode 11 is applied with a voltage having the same polarity as the toner potential, and causes the toner particles in the ink supplied from the ink supply port 5 to move in the vicinity of the recording electrode 2 by an electric field between the electrophoresis electrode 11 and a counter electrode (not shown). Is transported by the electrophoresis phenomenon. For this reason, in addition to the supply of the toner particles to the vicinity of the recording electrode 2 by the forced circulation of the ink by the pump, the toner particles move near the recording electrode 2 due to the electrophoretic movement of the toner particles.
Relatively higher than upstream. Further, the counter ion having a polarity opposite to the charge of the toner particles generated by the electrophoretic movement of the toner particles is moved in the direction opposite to the movement of the toner particles and is adsorbed on the migration electrode 11.

Therefore, when a high voltage pulse is applied to an arbitrary recording electrode 2, the charged toner in the ink is concentrated on the tip of the ink meniscus 8 formed on the surface of the recording electrode 2. The electric field generated at the recording electrode 2 guides the toner to a sufficient amount of the toner group 9 and flies in the direction of the recording paper (not shown) facing the recording head. Further, the ink is forcibly discharged to the ink discharge port 6 together with the surplus toner particles. The toner adhering to the recording paper and forming the recording dots is heated by a heater and fixed.

FIG. 5 is a schematic view of a TAB tape used in the electrostatic ink jet recording head of this embodiment. A method of manufacturing the TAB tape 12 will be briefly 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, the insulating coating member 17 is subjected to chemical vapor deposition where necessary, and used as a recording head. In this process, the base film 1
The inner lead portion 13 protruding from the portion where 0 is removed by etching becomes the recording electrode 2.

FIG. 6 is a plan view of a recording electrode portion according to another embodiment of the present invention, and FIG. 7 is a conceptual diagram of a recording sample using the recording head of FIG. In this embodiment,
In addition to the configuration of the above-described embodiment, the distance L between the electrode tips of the opposing recording electrodes 2 is configured to be an integral multiple of the pitch P between the recording electrodes 2, and a high voltage is applied to each of the opposing recording electrodes 2. Apply a drive pulse. With this configuration, in the case of recording with only the driving voltage Vp1 applied to one recording electrode 2, only the same recording dots can be obtained under the same driving conditions, but the driving voltage applied to the other recording electrode 2 can be obtained. By applying Vp2, two types of recording dot types can be obtained.

FIG. 8 is a plan view of a recording electrode portion according to still another embodiment of the present invention. In this embodiment, in addition to the configuration of the above-described embodiment, the opposite recording electrodes are arranged in a staggered configuration, and the recording density is doubled as compared with the same structure.

[0034]

As described above, in the electrostatic ink jet recording head of the present invention, since the inner electrode portion of the TAB tape is coated with an insulating coating to form the recording electrodes, the manufacturing process of the recording head is simple and the head is simple. This has the effect that the cost can be reduced.

In the present recording head, a plurality of recording electrodes must be formed with high density and high precision. However, by using the present manufacturing process, a stable recording electrode interval can be secured.

Further, since the head is tape-shaped, the head can be made thinner and smaller.

Further, the recording electrodes are arranged to face each other, and the ink is caused to flow between the recording electrodes so that excess toner particles and counter ions are forcibly discharged from the vicinity of the discharge electrodes. Therefore, since stable toner particles are always supplied to the vicinity of the recording electrode, reliable toner ejection can be obtained regardless of printing conditions.

[Brief description of the drawings]

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

FIG. 2 is a front view of the electrostatic ink jet recording head according to the embodiment as viewed from a direction indicated by an arrow A in FIG. 1;

FIG. 3 is a sectional view of a head end portion of the electrostatic ink jet recording head according to the embodiment.

FIG. 4 is a cross-sectional view (a cross-sectional view of FIG. 3B-B) of a recording electrode of the electrostatic ink jet recording head of the embodiment.

FIG. 5 is a schematic view of a head tape of the electrostatic ink jet recording head according to the embodiment.

FIG. 6 is a plan view of a recording electrode portion of another embodiment of the electrostatic ink jet recording head of the present invention.

FIG. 7 is a conceptual diagram of a recording sample of another embodiment of the electrostatic ink jet recording head of the present invention.

FIG. 8 is a plan view of a recording electrode portion of still another embodiment of the electrostatic ink jet recording head of the present invention.

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

FIG. 10 is a plan view and a sectional view of a head end portion of a conventional electrostatic ink jet recording head.

[Explanation of symbols]

 Reference Signs List 2 recording electrode 5 ink supply port 6 ink discharge port 8 ink meniscus 9 toner group 10 base film 11 migration electrode 12 TAB tape 13 inner lead portion 14 through hole 15 sprocket hole 16 ink flow path 17 insulating coating member 19 slit-shaped opening 20 holding member 21 ink flow

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryosuke Agematsu 7546 Yasuda, Oji, Kashiwazaki, Niigata Inside Niigata Nippon Electric Co., Ltd. (72) Inventor Hitoshi Minemoto 7546, Yasuda, Oji, Kashiwazaki, Niigata In-company (72) Inventor Hitoshi Takemoto 7546 Yasuda, Kashiwazaki City, Niigata Prefecture Inside Niigata Nippon Electric Co., Ltd. Inventor Tadashi Mizoguchi 7546 Yasuda, Kashiwazaki City, Niigata Prefecture Inside Niigata Nippon Electric Co., Ltd. (56) References JP-A-10-808 (JP, A) JP-A-10-809 (JP, A) JP-A-10 -34932 (JP, A) JP-A-10-44427 (JP, A) JP-A-10-67109 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/06

Claims (6)

(57) [Claims] 1. A base film having an insulating property, a slit-shaped opening opened in a part of the base film,
A plurality of recording electrodes formed on the surface of the base film and partially protruding from the slit-shaped opening and covered on the surface of the protrusion with an insulating coating member; and And a holding member that bends and holds the slit-shaped opening. 2. The electrostatic ink jet recording head according to claim 1, wherein a driving pulse is applied to each of the recording electrodes formed facing each other. 3. The electrostatic ink jet recording head according to claim 1, wherein an interval between the front ends of the recording electrodes formed opposite to each other is an integral multiple of a pitch of the recording electrodes. 4. The recording electrode according to claim 1, wherein said recording electrodes are formed so as to face each other in a staggered arrangement.
The electrostatic ink jet recording head according to the above. 5. The recording medium according to claim 1, wherein the insulating base film and the recording electrode are integrally formed on a two-layer or three-layer tape used in Tape Automated Bonding technology. 5. The electrostatic ink jet recording head according to 2, 3, or 4. 6. The electrophoretic electrode according to claim 1, further comprising an electrophoresis electrode configured to be in contact with ink containing toner particles flowing between the base film and the holding member.
6. The electrostatic ink jet recording head according to 3, 4 or 5.