JP2788887B2 - 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. Among them, there is a method in which a voltage is applied between an electrode provided on the back surface of a recording paper and a needle electrode facing the electrode, and a color material such as ink is caused to fly by an electrostatic force of the generated electric field, thereby performing recording.

FIG. 7 is a perspective view showing an example of a conventional ink jet recording head. Referring to FIG. 7, the print head 20 includes a substrate 21 and a cover 24,
A slit-shaped ink jet port 23 for holding ink is provided between these. A plurality of recording electrodes 22 are arranged on the substrate 21 in a direction from the ink ejection port 23 to the counter electrode 25. Electric wires (not shown) are connected to these recording electrodes 22, and a high-voltage pulse is selectively applied to these recording electrodes 22 during recording.

On the other hand, the printing paper 2 facing the recording electrode 22
A counter electrode 25 is provided on the back surface of the recording electrode 6, and an electric field is generated between the recording electrode 22 and the recording electrode 22 during recording. The recording electrode 22 is formed in a thin needle shape, and an electric field concentrates on the tip thereof.
As a result, electric charges are accumulated in the ink near the recording electrode 22.

The process of accumulating charges differs depending on the type of ink used. Electrostatic induction is dominant in conductive inks, and polarization is dominant in dielectric inks. Further, in the ink in which the coloring material particles serving as the base of the color are dispersed, the coloring material particles themselves have an apparent charge due to the zeta potential, and the charged coloring material migrates due to the electric field concentrated at the tip of the recording electrode 22. .

In any case, the Coulomb force acting on the accumulated electric charges causes the ink or the coloring material particles in the ink to be pulled in the direction of the counter electrode 25, that is, in the direction of the printing paper 26. When the Coulomb force becomes stronger than the surface tension of the ink, the ink flies and adheres to the printing paper 26. At this time, desired recording can be performed by appropriately controlling the high voltage pulse applied to the recording electrode 22 according to the print image.

However, since the conductivity and permittivity of the ink used for printing is higher than the conductivity and permittivity of air, the location where the electric field concentrates is not determined only by the arrangement of the recording electrodes 22, and the ink jetting is not performed. It also depends on the state of the ink meniscus at the outlet 23. That is, in FIG. 7, the ink meniscus is expected to be uniform in the longitudinal direction of the ink ejection port 23. However, in actuality, the processing accuracy of the ink ejection port 23 and the meniscus of the meniscus after the ink ejection is performed. Due to the vibration and the natural fluctuation of the meniscus, minute irregularities are generated.

In this case, the electric field is more concentrated on the minute meniscus projection near the recording electrode 22 due to the conductivity and dielectric properties of the ink. Once the meniscus starts to be deformed by the Coulomb force, the electric field is concentrated more strongly, and eventually, a minute unevenness of the meniscus is generated in the initial stage, so that the portion where the ink flies cannot be appropriately controlled. In other words,
Even if a high voltage pulse is applied to a certain recording electrode 22, the ink flies from a position that does not correspond to the recording electrode 22,
Recording may not be performed at a desired position. This leads to a significant deterioration in print quality.

For the purpose of solving the above disadvantages, Japanese Patent Application Laid-Open No.
JP-A-228162 discloses that, as shown in FIG.
A structure is disclosed in which a predetermined convex portion 28 is provided at a position corresponding to the recording electrode 27 at the front end portion of the device 1 so that the ink meniscus is provided with irregularities in advance and an electric field is concentrated on the recording electrode 27. . The print head 30 includes a reinforcing plate 29 at a position where each recording electrode 27 is partitioned.
Are arranged.

FIG. 9 is a perspective view showing another example of a conventional ink jet recording head. FIG. 10A is a top view of the head end of the ink jet recording head.
(B) is the AA sectional view. Referring to FIGS. 9 and 10, a substrate 41 is an insulator such as glass, and a plurality of recording electrodes 42 are formed on the surface thereof. Recording electrode 4
Reference numeral 2 denotes a pattern obtained by patterning a conductive material such as chromium sputtered over the entire surface of the substrate 41 by photolithography, for example, at a pitch of 300 dpi (dots per inch), that is, at an interval of about 85 μm. Recording electrode 42
Is connected to a driver (not shown), and can selectively apply a high-voltage pulse to the recording electrode 42 during recording.

The meniscus forming member 43 is formed by processing a photosensitive polymer film laminated on the substrate 41 by photolithography, and is formed at a position slightly receded from the leading end of the recording electrode 42 so as to overlap each recording electrode 42. Have been. The thickness of the photosensitive polymer film is 30 μm, and the width of the meniscus forming member 43 is about 30 μm. A cover 44 is mounted on the meniscus forming member 43 at a position further retracted from the tip of the meniscus forming member 43. The cover 44 is an insulating member, and the ink supply port 45 and the ink discharge port 46 are processed in advance. The substrate 41 and the cover 44 form a slit-shaped ink ejection port 47, and a meniscus forming member 43 riding on the recording electrode 42 protrudes outside the ink ejection port 47. The meniscus forming member 43 also has a purpose of supporting the cover 44, and therefore also partially extends below the cover 44. Further, when the meniscus forming member 43 is formed, a continuous wall surface is simultaneously formed on the head side portion and the rear end portion, so that the ink chamber is constituted together with the substrate 41 and the cover 44.

[0012]

However, in the above-mentioned conventional electrostatic ink jet recording head, a plurality of recording electrodes 42 are patterned by photolithography on a conductive material such as chromium which is formed by sputtering the entire surface of a substrate 41. Further, since the meniscus forming member 43 is formed 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 43 is formed of a photosensitive polymer film, the thickness of the meniscus forming member 43 is limited by the thickness of the film, and there is a problem that the ink supply amount is limited.

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

[0014]

According to the present invention, there is provided an electrostatic ink jet recording head comprising: a base film having an insulating property; and one end of the base film protruding from one end of the base film. And a plurality of recording electrodes formed on the other surface of the base film and not protruding from an end of the base film. A path electrode; and a cover configured above the flow path electrode surface and holding ink containing toner particles therein.

In the electrostatic ink jet recording head according to the present invention, the vicinity of the flow path electrode of the cover is in close contact with the flow path electrode, and the ink flows between the plurality of flow path electrodes. I do.

Further, in the electrostatic ink jet recording head according to the present invention, an electrophoretic electrode is provided in the cover so as to be in contact with the ink in order to convey the toner particles to the vicinity of the recording electrode. I do.

Further, in the electrostatic ink jet recording head according to the present invention, the relative positions of the flow path electrodes and the recording electrodes, the surfaces of which are covered with an insulating coating material and sandwiched by a base film, overlap each other. It is characterized by comprising.

Further, in the electrostatic ink jet recording head according to the present invention, when the recording electrode is not driven, a voltage is applied to the flow path electrode on the other surface.

Further, in the electrostatic ink jet recording head of the present invention, the thickness of the base film is equal to or less than the pitch between the plurality of recording electrodes.

Further, in the electrostatic ink jet recording head according to the present invention, the insulating base film, the recording electrode and the flow path electrode may be formed by a tape automated bond.
It is characterized by being integrally formed on a two-layer or three-layer tape used in the ng technology.

[0021]

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 an embodiment of the present invention. Referring to FIG. 1, a substrate 1 is an insulator such as plastic and supports a base film 10 from the back side. The base film 10 is an insulator such as polyimide and has a thickness of 5
A plurality of recording electrodes 2 are integrally formed on the surface thereof. The recording electrode 2 is a base film 10
A conductive material such as copper is pattern-plated thereon to a thickness of 20 to 30 μm, and is arranged at a pitch of 300 dpi, that is, at an interval of about 85 μm. Also, the recording electrode 2
The protrusions protrude independently from the end faces of the base film 10, and 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.

The base film 10 has a plurality of flow path electrodes 17 integrally formed on the back surface thereof. Channel electrode 1
7, a conductive material such as copper is pattern-plated to a thickness of 20 to 30 μm on the base film 10 similarly to the recording electrode 2, and has a pitch of 300 dpi, that is, about 85 μm.
It is configured not to protrude from the base film 10 at intervals. The channel electrode 17 and the recording electrode 2 are arranged in a staggered arrangement with the base film 10 interposed therebetween.

According to the recording head of the present invention, the base film 1
A tape-shaped head in which the recording electrode 2 and the flow path electrode 17 are integrally formed on the head 0 is used.
A two-layer or three-layer TAB tape used in a utomated bonding (TAB) technique is used, and an insulating coating member 3 is formed by chemical vapor deposition of a parylene resin.

The cover 4 is mounted on the base film 10 at a position where the flow path electrode 17 on the rear surface is located and does not cover the projection of the recording electrode 2. The cover 4 is an insulating member, and the ink supply port 5 and the ink discharge port (not shown) are processed in advance, and the space formed by the base film 10 and the cover 4 forms an ink chamber.
The ink is filled from the ink supply port 5 and filled therein. Further, the cover 4 has a configuration in which the cover 4 is adhered to the base film 10. Base film 10
The pattern of the upper flow path electrode 17 has a thickness of 20 to 30.
Since there is about μm, the space between the portion where the pattern of the flow path electrode 17 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.

The ink jet head of the present embodiment is
It 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.

FIG. 2 is an enlarged view (FIG. 2 (a)) of the vicinity of the ink ejection port 7 (part A) when ink is supplied from the ink jet head of the present embodiment (FIG. 2 (a)).
Section (FIG. 2 (b)) and BB section (FIG. 2 (c))
Is shown. Referring to FIG. 2 in conjunction with FIG.
An ink meniscus 8 is formed at the ink ejection port 7 by the surface tension. Since a negative pressure is applied to the ink 6 in the head and the recording electrode 2 protrudes from the base film 10 and 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, an 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 8 protruding from the recording electrode 2. The charged toner in the ink 6 is guided by this electric field, is drawn out from the tip of the protruding ink meniscus 8, and forms a toner group 9 in the direction of a counter electrode (not shown) facing the recording head, that is, in the printing paper direction. To fly. The toner adhering to the printing paper and forming the recording dots is heated and fixed by the heater.

FIG. 3 is a schematic view of a TAB tape used in the electrostatic recording head of the present invention. Referring to FIG.
A method of manufacturing the AB 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 protruding inner lead portion 13 is recorded where the base film 10 is removed by etching. Further, by performing a similar process on the back surface, the flow path electrode 17 on the back surface is formed.

FIG. 4 is a perspective view of another embodiment of the present invention. Referring to FIG. 4, in this embodiment, in addition to the configuration of the above-described embodiment, a migration electrode 11 that is in contact with ink 6 is formed inside cover 4. Electrophoresis electrode 1
Reference numeral 1 denotes a state in which a voltage having the same polarity as the potential of the toner is applied, and the toner particles in the ink 6 supplied from the ink supply port 5 are electrically transferred to the vicinity of the recording electrode 2 by an electric field between the migrating electrode 11 and a counter electrode (not shown). Convey by electrophoresis.

FIG. 5 is an enlarged view (FIG. 5 (a)) of the vicinity of the ink ejection port 7 when the ink 6 is supplied from a recording head according to still another embodiment of the present invention when viewed from above (FIG. 5 (a)). −
Section A (FIG. 5 (b)) and section BB (FIG. 5 (c))
Is shown. 5 (a), 5 (b) and 5 (c), the present embodiment differs from the configuration of the above-described embodiment shown in FIG. is there. That is, the flow path electrodes 17 integrally formed on the back surface of the base film 10 are made of a conductive material such as copper on the base film 10 in the same manner as the recording electrode 2.
Patterned to a thickness of μm, 300 dpi
Base film 10 at a pitch, ie, about 85 μm intervals.
It is configured not to protrude from. Further, the surface of the flow path electrode 17 is uniformly covered with the insulating coating member 3 with a thickness of 10 μm or less, similarly to the recording electrode 2. The channel electrode 17 and the recording electrode 2 are disposed so as to overlap with the base film 10 therebetween.

FIG. 6 shows a drive pulse sequence in the embodiment of FIG. Referring to FIG. 6, when a high voltage pulse Vp, which is a recording voltage, is applied to the recording electrode B, an electric field is concentrated on the tip of the ink meniscus protruding from the recording electrode B. The charged toner in the ink is guided by this electric field and is concentrated from the ink chamber to the recording electrode B. At this time, in order to prevent the toner from moving to the adjacent recording electrodes A and C, a high voltage pulse V which is a recording voltage is applied to the flow path electrodes A and C.
By applying a voltage lower than p or a reverse polarity voltage Vc, the toner from the tip of the protruding ink meniscus on the recording electrode A and recording electrode C side due to the electric field of the high voltage pulse Vp which is the recording voltage applied to the recording electrode B Flying can be prevented.

[0032]

As described above, in the electrostatic ink jet recording head of the present invention, the inner lead portion of the TAB tape is coated with an insulating coating to form a recording electrode. There is an effect that cost can be reduced. In addition, since a flow path electrode is formed on the back surface, a gap between the flow path electrode and the base film is used as an ink flow path, and a drive voltage is applied to the flow path electrode to control ejection, high-quality printing is obtained. Can be In addition, the present recording head needs to configure a plurality of recording electrodes with high density and high precision, but by using this manufacturing process,
A stable recording electrode interval and electrode protrusion amount can be secured. Further, since the head has a tape shape, the head can be made thinner and smaller.

[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 an AA cross-sectional view of the vicinity of an ink ejection port (part A) in a state where ink is supplied in the inkjet head of the embodiment of FIG. (FIG. 2B) and a BB cross-sectional view (FIG. 2C).

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

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

FIG. 5 is an enlarged view (FIG. 5A) 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. 5A).
A sectional view (FIG. 5B) and BB sectional view (FIG.
(C)).

FIG. 6 is a diagram showing a drive pulse sequence in the embodiment of FIG.

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

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

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

10 is a top view (FIG. 10A) of a head end portion of the ink jet recording head of FIG. 9 and a cross-sectional view taken along the line AA (FIG. 10B).

[Explanation of symbols]

 Reference Signs List 1 substrate 2 recording electrode 3 insulating coating member 4 cover 5 ink supply port 6 ink 7 ink ejection port 8 ink meniscus 9 toner group 10 base film 11 migration electrode 12 TAB tape 13 inner lead section 14 through hole 15 sprocket hole 16 ink flow Road 17 Channel electrode

Continuing on the front page (72) Inventor Hitoshi Minemoto Niigata Prefecture Kashiwazaki City Tajiri Industrial Park 7546 Niigata Nippon Electric Co., Ltd. 72) Inventor Ryosuke Agematsu 7546 Tajiri Industrial Park, Kashiwazaki City, Niigata Pref. Niigata Nippon Electric Co., Ltd. (72) Inventor Tadashi Mizoguchi 7546 Tajiri Industrial Park, Kashiwazaki City, Niigata Pref. Tsuji 7546 Tajiri Industrial Park, Kashiwazaki City, Niigata Prefecture Niigata Nippon Electric Co., Ltd. (56) References JP-A-3-504836 (JP, A) JP-A-55-87563 (JP, A) JP-A-60-228162 ( JP, A) JP-A-6-21936 (JP, A) JP-A-7-1739 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/06

Claims (7)

(57) [Claims] 1. A base film having an insulating property, and one end of the base film formed on one surface of the base film so as to protrude from an end of the base film, and further coated on the surface with an insulating coating material. A plurality of recording electrodes, a plurality of flow electrodes configured on the other surface of the base film and configured not to protrude from an end of the base film, and a plurality of flow electrodes configured on the flow electrode surface. And a cover for holding ink containing toner particles. 2. The electrostatic ink jet recording according to claim 1, wherein the vicinity of the flow path electrode of the cover is in close contact with the flow path electrode, and the ink flows between the plurality of flow path electrodes. head. 3. The electrophoretic electrode according to claim 1, wherein an electrophoresis electrode is provided in the cover so as to be in contact with the ink in order to transport the toner particles to the vicinity of the recording electrode.
The electrostatic ink jet recording head according to the above. 4. The recording electrode according to claim 1, wherein said recording electrode and said flow path electrode, the surfaces of which are covered with an insulating coating material and are sandwiched by a base film, overlap each other. An electrostatic ink jet recording head according to 1, 2, or 3. 5. The electrostatic ink jet recording head according to claim 4, wherein when the recording electrode is not driven, a voltage is applied to the flow path electrode on the other surface. 6. The electrostatic ink jet recording head according to claim 1, wherein the thickness of the base film is equal to or less than the pitch between the plurality of recording electrodes. 7. The tape-automated Bonn film, wherein the insulating base film, the recording electrode and the flow path electrode are
3. A two-layer or three-layer tape used in a ding technique, wherein the tape is integrally formed.
7. The electrostatic ink jet recording head according to 3, 4, or 6.