JP2786162B2 - Electrostatic inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art The non-impact recording method has recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Above all, the ink jet recording method capable of recording directly on a recording medium at high speed with a simple mechanism and recording on plain paper is an extremely powerful recording method, and various methods have been proposed. I have.

A voltage is applied between a recording electrode provided on the back surface of a recording medium and a needle electrode facing the recording medium, 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 a way. FIGS. 8 to 1 show an example of the system.
This will be described with reference to FIG.

[0004] The substrate 1 is made of an insulator such as glass, and a plurality of recording electrodes 2 are formed on the surface thereof. The recording electrodes 2 are obtained by patterning a conductive material such as chromium sputtered on the entire surface of the substrate 1 by photolithography, and are arranged, for example, at a pitch of 300 dpi, that is, at intervals of about 85 μm. The recording electrode 2 is connected to a driver (not shown), and can selectively apply a high voltage pulse to the recording electrode 2 during recording.

The meniscus forming member 18 is obtained by processing a photosensitive polymer film laminated on the substrate 2 by photolithography. The meniscus forming member 18 is located at a position slightly receded from the leading end of the recording electrode 2 so as to overlap each recording electrode 2. Is formed. Since the thickness of the photosensitive polymer film is 30 μm, the width of the meniscus forming member 18 is also about 30 μm.

An upper cover 4 made of an insulating material is mounted on the meniscus forming member 18 at a position retracted from the tip of the meniscus forming member 18, and the upper cover 4 has an ink supply port 5 and an ink supply port. An outlet 6 is formed. Further, a slit-shaped ink ejection port 7 is formed between the substrate 1 and the upper cover 4, and a meniscus forming member 18 riding on the recording electrode 2 protrudes from the tip of the ink ejection port 7.

The meniscus forming member 18 supports the upper cover 4 and also has a purpose of forming the ink flow path 16, so that it partially continues below the upper cover 4. Further, in order to concentrate the toner particles in the ink and supply it to the vicinity of the ink ejection port 7 through the ink flow path 16, an electrophoresis electrode 11 is provided behind the ink flow path 16.

When a voltage is applied between the migrating electrode 11 and an electrode provided on the back side of the recording medium, the toner particles in the ink move due to the electrophoretic force due to the electric field formed between them, and the vicinity of the ink ejection port 7 Focus on This ink forms an ink meniscus 8 by surface tension, and is further drawn by the electric field from the tip of the ink meniscus 8,
As a toner group 9, the toner flies and adheres to the recording medium.

[0009]

However, in the above-described conventional electrostatic ink jet recording apparatus, since the recording electrodes are physically arranged on the same straight line, a drive pulse is applied to each recording electrode at the same timing. Unless otherwise, there is a problem that a recording position shift occurs.

Further, in order to apply drive pulses at the same timing, drive circuits are required in a number corresponding to each recording electrode, and there is a problem that the drive circuits become complicated and expensive. On the other hand, when a matrix drive circuit is configured to reduce the number of drive circuits, a print position shift occurs because the drive pulse timing is different for each print electrode as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in an electrostatic ink jet recording apparatus for discharging only toner particles in ink by an electrostatic field, recording is performed by physically offsetting recording electrodes in advance. Prevents recording position shift, which is a problem when driving electrodes in matrix,
An object is to provide a reliable low-cost multi-element head.

[0012]

According to the present invention, there is provided an electrostatic ink jet recording apparatus comprising: a base film having an insulating property and a notch at a front end; and a base film formed on a surface of the base film, and one end of which is formed on the base film. A plurality of recording electrodes formed so as to protrude from an end on the side where the cut of the base film is provided, and the surface of the protruding portion is further covered with an insulating coating member; and the recording electrodes are divided into a plurality of groups and driven. Drive circuit, a substrate that holds the base film offset for each cut end portion of the base film, and sandwiches the base film, and ink containing toner particles from the front surface to the back surface of the base film. An upper cover and a lower cover for supplying and holding the ink by passing through the gap between the recording electrodes; Upstream of said recording electrodes in Ppakaba, and electrophoresis electrode disposed so as to be in contact with the ink,
And a counter electrode disposed at a position facing the recording electrode with the recording medium interposed therebetween.

Further, the electrostatic ink jet recording apparatus according to the present invention is characterized in that the recording electrodes are formed integrally with a plurality of layers of tape used in the Tape Automated Bonding technique.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows one embodiment of the present invention, and is a perspective view of a head section of an electrostatic ink jet recording apparatus.

The substrate 1 is made of an insulator such as plastic, and supports the base film 10 from the back side.
The base film 10 is made of an insulator such as polyimide, has a thickness of about 50 μm, and has a plurality of recording electrodes 2 integrally formed on the surface thereof. Also, the leading end of the base film 10 is divided into a plurality of groups,
The recording electrode 2 is divided for each group.

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 protrusions independently protrude from the front end surface of the base film 10, and the protrusion amount is about 80 μm to 500 μm. Further, the tip surface of the recording electrode 2 is uniformly covered with the insulating coating member 17 with a thickness of 10 μm or less.

In the recording head of the present invention, a tape-shaped head in which the recording electrodes 2 are integrally formed on the base film 10 is used. Specifically, Tape Automated Bonding
The TAB tape used in the (TAB) technique is used, and the insulating coating member 17 is further formed by chemical vapor deposition of parylene resin.

The upper cover 4 and the lower cover 3 are positioned so as not to cover the protruding portions of the recording electrodes 2 so that the base film 10
These members are attached so as to sandwich the recording electrode 2 projecting from above from above and below, and all are made of an insulating member. An ink supply port 5 is formed in the upper cover 4, and a space between the base film 10 and the upper cover 4 is
The ink chamber 20 is filled with the ink supplied from the ink supply unit 5. In addition, a slit-shaped ink ejection port 7 is formed between the tip of the Ach cover 4 and the base film 10. On the other hand, the lower cover 3
The ink outlet 6 (not shown) is processed, and the space between the base film 10 and the lower cover 3 is
Is composed.

The ink supplied to the ink chamber 20 on the side of the Ach cover 4 passes from the ink chamber 20 to the space between the recording electrodes 2, passes through the ink chamber 21 from the vicinity of the ink ejection port 7, and passes through the ink chamber together with excess toner particles. It is forcibly discharged from the discharge port 6. In addition, this inkjet head
It is connected to an ink tank (not shown) via a tube, and a negative pressure of about 1 cmH ₂ O is applied.
The 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 migration electrode 11 that is in contact with ink is formed inside the Ach cover 4. A voltage having the same polarity as the potential of the toner is applied to the migrating electrode 11, and the toner particles in the ink supplied from the ink supply port 5 are separated by an electrophoretic phenomenon caused by an electric field between the migrating electrode 11 and a counter electrode (not shown). It is conveyed to the vicinity of the recording electrode 2. As a result, in addition to the supply of the toner particles to the vicinity of the ink ejection port 7 due to the forced circulation of the ink by the pump, the toner particle concentration in the vicinity of the ink ejection port 7 is changed from the ink chamber 20 by the electrophoretic movement of the toner particles. It is relatively higher than upstream.

FIGS. 2 and 3 are an enlarged view and a sectional view of the vicinity of the ink ejection port 7 when ink is supplied, as viewed from above. 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
As shown in FIG. 3, when the ink meniscus 8 is viewed from the side, the side of the Ach cover 4 is obliquely downwardly concave, and the side of the lower cover 3 is formed of the ink meniscus 8 because it protrudes from the base film 10, the upper cover 4 and the lower cover 3. It becomes symmetrical. Further, since each recording electrode 2 individually protrudes toward the tip end of the ink ejection port 7, an ink meniscus 8 is individually formed corresponding to each recording electrode 2 when viewed from above as shown in FIG. It will be.

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 8 projecting from the recording electrode 2. The charged toner in the ink is guided by an electric field generated between the counter electrode (not shown) and the recording electrode 2, and is drawn out from the tip end of the protruding ink meniscus 8 to form a toner group 9, forming a recording electrode 9. 2, which flies in the direction of the recording medium. The toner that has adhered to the recording medium and formed the recording dots is heated by a heater and fixed.

FIG. 4 is a front view of a portion indicated by A in FIG. 1 of the head of the electrostatic ink jet recording apparatus according to the present invention. Recording electrode 2 formed on base film 10
Are divided into a plurality of groups at the leading end by slits of the base film 10. Also, when viewed from the front end side, the base film 10 mounting portion of the substrate 1 has a structure inclined at a certain angle so that each recording electrode 2 is offset (inclined) at a certain angle for each group. Has become. Further, the recording electrode 2
Are electrically connected to each other at the same position corresponding to the inclination between the individual groups, and are matrix-connected.

FIG. 5 is a schematic view of a TAB tape used in the electrostatic ink jet recording apparatus according to the present invention. T
A method of manufacturing the AB tape 12 will be schematically described.

First, after flash plating is performed on a tape-like base film 10 made of polyimide or the like having sprocket holes 15 at both ends, a dry film is laminated, and a pattern is formed by exposure and development. Then
After pattern plating of copper or the like, the base film 10 is etched to form the through holes 14. After that, remove the resist film, apply finish plating, and
An insulating coating member is chemically vapor-deposited at a necessary portion and used as a recording head. In this process, the inner lead portions 13 projecting from the portions where the base film 10 is removed by etching become the recording electrodes 2.

FIG. 6 is a driving pattern diagram of the electrostatic ink jet recording apparatus of the present invention, and FIG. 7 is a schematic view of a printing result of the electrostatic ink jet recording apparatus of the present invention. As shown in FIG. 6, the recording electrodes 2 electrically connected in a matrix are driven with a shift of an offset time T for each group. As a result, when the recording electrodes 2 are physically formed on the same straight line, as shown in FIG. 7A, the recording dots are offset by the offset distance L for each group connected in a matrix. Occur.

On the other hand, in the present invention, the recording electrode 2 is offset in advance to such an extent that the offset distance L is guaranteed. As a result, as shown in FIG. 7 (B), no recording position shift due to each offset time T occurs in the recording dots, and high printing quality can be obtained.

[0028]

As described above, in the electrostatic ink jet recording apparatus according to the present invention, since the insulating electrodes are applied to the inner leads of the TAB tape to form the recording electrodes, the head manufacturing process is simple. There is an effect that the cost of the head is reduced.

Further, in the present recording head, it is necessary to form a plurality of recording electrodes with high density and high accuracy. However, by using the manufacturing process according to the present invention, a stable recording electrode interval and electrode protrusion amount can be obtained. Can be secured. Furthermore, since the head is in a tape shape, the head can be made thinner and smaller.
Furthermore, since the ink is made to flow through the gap between the recording electrodes, surplus toner particles and counter ions are forcibly discharged from the vicinity of the recording, so that stable toner particles are always supplied to the vicinity of the recording electrode. Thus, a reliable toner supply can be obtained regardless of printing conditions.

On the other hand, since the recording electrodes formed on the base film are offset for each base film by the matrix drive offset time, a recording position shift due to the offset time does not occur, and high printing quality can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a top view of a head end portion of the electrostatic ink jet recording apparatus of the present invention.

FIG. 3 is a cross-sectional view taken along line III-III of a head end portion of the electrostatic ink jet recording apparatus of the present invention.

FIG. 4 is a front view of a head end portion of the electrostatic ink jet recording apparatus of the present invention.

FIG. 5 is a schematic view of a head tape used in the electrostatic ink jet recording apparatus of the present invention.

FIG. 6 is a drive pattern diagram of the electrostatic ink jet recording apparatus of the present invention.

FIG. 7 is a print pattern diagram of the electrostatic ink jet recording apparatus of the present invention.

FIG. 8 is a top perspective view of a conventional electrostatic ink jet recording head.

FIG. 9 is a top view of a head end portion of a conventional electrostatic ink jet recording head.

FIG. 10 is a cross-sectional view taken along line XX of the head end of a conventional electrostatic ink jet recording head.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 recording electrode 3 lower cover 4 upper cover 10 base film 11 migration electrode 12 TAB tape 17 insulating coating member

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadashi Mizoguchi Niigata Prefecture Kashiwazaki-shi Oaza 7546 Yasuda Niigata Nippon Electric Co., Ltd. In-company (72) Inventor Hitoshi Takemoto 7546 Yasuda, Kashiwazaki-shi, Niigata Inside Niigata Nippon Electric Co., Ltd. (72) Inventor Yoshihiro Hagiwara 7546, Yasuda, Oji, Kashiwazaki-shi, Niigata Inventor Toru Yakushiji 7546 Yasuda, Kashiwazaki-shi, Niigata Prefecture Niigata Nippon Electric Co., Ltd. (56) References JP-A-62-227755 (JP, A) JP-A-62-217375 (JP, A) JP-A 62 -256660 (JP, A) JP-A-59-81178 (JP, A) JP-A-62-267147 (JP, A) JP-A-57-203568 (JP, A) JP-A-1-122462 (JP, A) ) (58)査the field (Int.Cl. ^6, DB name) B41J 2/385 B41J 2/06

Claims (2)

(57) [Claims] 1. A base film having an insulating property and having a cut at a front end portion, and a base film formed on a surface of the base film, and one end of which is formed to protrude from an end portion of the base film where the cut is formed. A plurality of recording electrodes whose surfaces are further covered with an insulating coating member, a driving circuit for driving the recording electrodes by dividing the recording electrodes into a plurality of groups, and a cut end portion of the base film. A substrate that holds the base film offset every time, while sandwiching the base film from above and below, and passing the ink containing toner particles through the gap between the recording electrodes from the front surface to the back surface of the base film, An upper cover and a lower cover for supplying and holding the recording medium; And a counter electrode disposed at a position facing the recording electrode with a recording medium interposed therebetween. 2. The method according to claim 1, wherein the recording electrode is a Tape Automated Bondi.
2. The electrostatic ink jet recording apparatus according to claim 1, wherein the electrostatic ink jet recording apparatus is formed integrally with a plurality of layers of tape used in the ng technique.