JPH1044429A - Electrostatic ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To jet an ink droplet containing toner particles in an electrostatic field by providing a base plate having electrode pads connected with respective jet electrodes and a head board secured to a desired position thereby jetting an ink droplet stably in an electrostatic field. SOLUTION: The electrostatic ink jet recording head comprises a head board 2 where a jet electrode 7 made of a conductive material is provided on any one of the opposite walls or the bottom face at each recess in a base board 6 made of an insulating material and machined to have protrusions and recesses, an electrode pad 8 connected with each jet electrode 7, a base plate 3 securing the head board 2 to a desired position, and an upper cover 5 formed above the base plate 3 while being set back partially from the protruding/recessed part on the jet electrode 7 side and forming a chamber 4 for holding an ink 1 along with the base plate 3. The jet electrodes 7 are formed on the opposite walls and the bottom face at each recess at an interval corresponding to a desired resolution.

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 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 record directly on a recording medium at high speed with a simple mechanism and that can record on plain paper is an extremely powerful recording method, and various methods have been proposed so far. Have been. In it, an ink in which toner particles are dispersed in a carrier liquid is used, and a voltage is applied between a needle-shaped recording electrode and an electrode provided on the back of the recording paper opposed thereto, and the electrostatic force of the generated electric field is used. There is a method of recording by causing a color material in ink to fly.

FIG. 7 shows, for example, Japanese Patent Application No. 07-120252.
FIG. 1 is a perspective view showing an example of this conventional electrostatic ink jet recording head shown in the specification. FIG. 8 is a plan view and a sectional view of a head end portion of the electrostatic ink jet recording head. An example of this conventional electrostatic ink jet recording head will be described with reference to FIGS.

The substrate 101 is made of a flat insulating material, and a plurality of ejection electrodes 102 are formed on the surface thereof at intervals equivalent to a desired resolution. The ejection electrode 102
After a metal material such as u, Ni or the like is sputtered on the entire surface of the substrate 101, the discharge electrode 102 is formed on the substrate 101 by exposure and development via a patterned mask. The ejection electrodes 102 are formed as independent electrodes. One end of each ejection electrode 102 is connected to a driver (not shown), and a high voltage pulse is selectively applied at the time of recording. Further, the surface of the substrate 101 on which the ejection electrodes 102 are formed is spin-coated with an insulating coating material so that the ink and the ejection electrodes 102 are insulated.

[0005] The meniscus forming member 103 includes the discharge electrode 1.
After laminating or spin-coating an insulative and photosensitive resist material on the substrate 101 on which the discharge electrodes 1 have been formed, each of the discharge electrodes 1 is exposed and developed through a mask in which the shape of the meniscus forming member 103 is patterned.
02 is formed so as to overlap with the reference numeral 02. A cover 104 is mounted on the meniscus forming member 103 at a position retracted from the tip of the meniscus forming member 103. The cover 104 is made of an insulating material, and the ink supply port 105 and the ink discharge port 106 are processed in advance.

[0006] The substrate 101, the cover 104, and the meniscus forming member 103 on each discharge electrode 102 form
A minute slit-shaped discharge opening 107 is formed, and ink supplied from the ink supply port 105 is supplied to the discharge opening 10.
7, the liquid is supplied to the distal ends of the meniscus forming members 103 protruding outward from the discharge openings 107, and a meniscus is formed at the distal ends of the respective meniscus forming members 103.

[0007]

The first problem is that the conventional electrostatic ink jet recording head described above cannot follow the supply of ink in the high-speed driving area. The reason is that since the meniscus forming member is formed using a photosensitive resist material, the thickness is limited to several tens of μm, and the flow path resistance of the discharge opening due to the thickness of the meniscus forming member increases. It is in.

A second problem is that the above-mentioned conventional electrostatic ink jet recording head cannot obtain a stable meniscus shape. The reason is that, since the meniscus forming member is formed by exposure and development by photolithography, the corner of the tip of the meniscus forming member, which is the ink discharge point, has a slack shape and is located at a position receded from the end surface of the substrate. It is because it is formed in.

SUMMARY OF THE INVENTION The object of the present invention has been made in view of the above points, and stabilizes the ejection of ink droplets in a high-speed driving region, and discharges ink droplets containing toner particles in ink by an electrostatic field. An object of the present invention is to provide an electrostatic ink jet recording head to be used.

[0010]

An electrostatic ink jet recording head according to the present invention provides an electric field to ink in which charged toner particles are dispersed, and discharges the toner particles by an electrostatic force generated by the electric field. An electrostatic ink jet recording head for performing printing, wherein a discharge electrode made of a conductive material is formed on one of both walls and a bottom surface of each concave portion of a base substrate made of an insulating material processed into an uneven shape. A substrate, a base plate having electrode pads respectively connected to the ejection electrodes, and fixing the head substrate at a desired position; and a base plate formed above the base plate, a part of which is provided at the ejection electrode of the head substrate. An ink chamber that is disposed at a position retracted from the uneven portion on the distal end side and that holds the ink together with the base plate is formed. And a Ppakaba.

In the electrostatic ink jet recording head according to the present invention, the interval between the convex portion and the concave portion of the head substrate is regularly formed at an interval of a desired resolution. Is characterized in that the independent discharge electrodes are formed at the same intervals as the concave portions.

Further, an electrostatic ink jet recording head according to the present invention is characterized in that the uneven surface of the head substrate on which the discharge electrodes are formed is coated with an insulating coating material.

Further, in the electrostatic ink jet recording head of the present invention, in the cross section of the concave portion of the head substrate, the width of the concave portion is such that a capillary force can be generated, and the depth of the concave portion is larger than the width of the concave portion. It is characterized by being formed to be deep.

Further, in the electrostatic ink jet recording head according to the present invention, the migrating electrode for applying a certain bias voltage to the ink in the ink chamber is electrically connected to the ink in the ink chamber. It is characterized by being provided.

[0015]

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

FIG. 1 is a schematic view of an embodiment of an electrostatic ink jet recording head according to the present invention. FIG. 1 (a) is a perspective view thereof, and FIG. 1 (b) is a detailed view of a portion A. .

Referring to FIG. 1, the electrostatic ink jet recording head of this embodiment applies an electric field to the ink 1 in which the charged toner particles are dispersed, and discharges the toner particles by an electrostatic force generated by the electric field. And an ink jet recording head for performing printing, wherein an ejection electrode 7 made of a conductive material is provided on one of both walls and a bottom surface of each recess of a base substrate 6 made of an insulating material processed into an uneven shape. A base plate 3 having the formed head substrate 2 and electrode pads 8 connected to the discharge electrodes 7 and fixing the head substrate 2 at a desired position, and a base plate 3 formed on the base plate 3. Part is head substrate 2
And an upper cover 5 forming an ink chamber 4 for holding the ink 1 together with the base plate 3 together with the base plate 3.

The head substrate 2 includes a base substrate 6 made of an insulating material such as glass, and a discharge electrode 7 made of a conductive material such as Ni or Cu. The surface of the base substrate 6 is processed into an irregular shape so that each concave portion and convex portion are formed at the same interval as the desired resolution, and the discharge electrode 7 is provided on both walls and the bottom surface of each concave portion with the desired resolution. They are formed at the same interval.

The base plate 3 is made of an insulating material. On the surface of the base plate 3, electrode pads 8 for connecting to a drive circuit (not shown) and a drive voltage inputted from each electrode pad 8 are applied to each discharge electrode 7. Conductor 9 for feeding
Are formed. Also, at a desired position along the end surface of the base plate 3, one of the concave and convex end surfaces of the head substrate 2 is fixed so as to face the outside of the base plate 3,
Each discharge electrode 7 and each conductor 9 are electrically connected by wire bonding or the like. The connection between the discharge electrode 7 and the conductor 9 and each conductor 9 are preferably coated and sealed with an insulating resin.

The upper cover 5 is made of an insulating material such as a plastic molded product, and is disposed on the base plate 3 to form an ink chamber 4 for holding the ink 1 together with the base plate 3. An ink supply port 10 for supplying the ink 1 into the ink chamber 4 and an ink 1 in the ink chamber 4 are provided on the upper cover 5.
An ink discharge port (not shown) for discharging ink is formed, and the ink supply port 10 and the ink discharge port are connected to an ink circulation pump (not shown) and an ink tank via a tube. Further, a part of the upper cover 5 is disposed above the head substrate 2, and covers an upper portion of the uneven surface at a position retreated from the uneven portion at the tip on the side of the discharge opening 11, thereby forming a concave portion of the head substrate 2. With ink chamber 4
A flow path 12 for supplying the ink 1 from the inside to the uneven portion of the discharge opening 11 is formed.

FIG. 2 is a view showing a manufacturing process of the base substrate of the present invention. With reference to FIG. 2, a manufacturing process of the base substrate will be described.

FIG. 2A shows an embodiment of a base substrate manufacturing process using dicing. The surface of the base substrate 6 made of a flat insulating material is coated with a desired resolution using a dicing blade 13. The surface of the base substrate 6 is processed into a concavo-convex shape by dicing at the same interval and a desired cut amount.

FIG. 2B shows an embodiment of a manufacturing process of the base substrate utilizing laser processing. A portion where a concave portion is formed on the surface of the base substrate 6 made of a flat insulating material is transparent. By irradiating a laser beam such as an excimer laser or the like through the mask 14 on which the pattern is formed, and adjusting the irradiation time, the surface of the base substrate 6 is processed into an uneven shape.

FIG. 3 is a process chart for manufacturing the head substrate of the present invention. The manufacturing process of the head substrate will be described with reference to FIG.

By the processing shown in FIG. 2A or FIG. 2B, Cu, Ni are formed on the entire uneven surface of the base substrate 6 (FIG. 3A) made of an insulating material having an uneven surface.
The conductive material such as is deposited by sputtering to form the conductor layer 15 (FIG. 3B). Next, by removing the conductive layer 15 on the upper surface of the convex portion by milling or the like on the concave-convex surface side of the base substrate 6, the head substrate 2 in which the independent discharge electrodes 7 composed of the conductive layer 15 are formed in each concave portion. (FIG. 3 (c)). Further, in order to insulate each ejection electrode 7 from the ink 1, the entire head substrate 2 is covered with an insulating coating material 16 (FIG. 3D).

After the head substrate 2 is formed on a single wafer-shaped base substrate 6 by a plurality of head substrates 2 by the above-described manufacturing method, the wafer is cut into individual head substrates. 2 may be obtained.

FIG. 4 is an apparatus configuration diagram of a recording head according to an embodiment of the present invention. Referring to FIG. 4, a counter electrode 18 also serving as a platen for transporting a recording paper 17 to which a surface potential is 0 V or a negative potential is applied in a direction opposite to the ejection opening 11 of the recording head of this embodiment. It is arranged. The recording head is arranged such that a corner formed by the upper surface of the convex portion of the head substrate 2 and the uneven end surface on the side of the ejection opening 11 is closest to the counter electrode 18. A minute discharge gap is provided between the electrode 18 and the electrode 18. The recording paper 17 is fed between the ejection gap between the recording head and the counter electrode 18 along the counter electrode 18.

FIG. 5 is a drive explanatory diagram of one embodiment of the recording head of the present invention. Referring to FIG. 5, at the time of printing, a driving pulse voltage is applied to a desired ejection electrode 7 formed in the concave portion, and electric field lines 22 as shown in the figure are generated by an electric field between the ejection electrode 7 and the counter electrode 18. I do. The meniscus 19 of the ink near the discharge point where the ink enemy 21 discharges forms a meniscus 19 that protrudes along the protruding portion as shown in FIG. The curvature change of the meniscus 19 is the largest at the corner 20 formed by the end face. Ink drop 21
Is ejected along the lines of electric force 22 with the convex portion on the meniscus 19 to which the electric field is applied and the corner portion 20 having a large change in curvature as an ejection point. The corners 20 on both sides of the electrode 7 are used as ejection points, and the ejection electrode 7 and the counter electrode 18 are used.
The ink droplets 21 are ejected along the lines of electric force 22 generated between them.

FIG. 6 is a schematic view of another embodiment of the electrostatic ink jet recording head of the present invention. Referring to FIG. 6, an electrostatic ink jet recording head according to this embodiment has a configuration in which the electrophoretic electrode 23 that is in contact with the ink 1 is provided in the ink chamber 4 in addition to the configuration of the embodiment shown in FIG. I have. A voltage having the same polarity as the potential of the toner is applied to the migration electrode 23, and the toner particles in the ink 1 supplied from the ink supply port 10 to the ink chamber 4 are moved to the migration electrode 2.
The toner particles are conveyed to the vicinity of the discharge electrode 7 by utilizing an electrophoretic phenomenon of toner particles caused by an electric field generated between the counter electrode 3 and an unshown counter electrode.

[0030]

The first effect is that the supply of ink in the high-speed driving area can follow. The reason is that by forming the unevenness on the head substrate surface using the manufacturing process according to the present invention, the concave portion functioning as a flow path for supplying ink to the ejection points can be processed at an arbitrary depth. This is because the flow path resistance of the concave portion is reduced.

The second effect is that a clear discharge point at which ink droplets are discharged can be obtained. The reason is that the meniscus of the ink is formed on the end face of the concave / convex portion on the side of the ejection opening, so that the shape of the meniscus is stabilized.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an electrostatic ink jet recording head according to the present invention, wherein FIG. 1A is a perspective view thereof, and FIG.

FIG. 2 is a manufacturing process diagram of a base substrate of the present invention.

FIG. 3 is a manufacturing process diagram of the head substrate of the present invention.

FIG. 4 is an apparatus configuration diagram of an embodiment of a recording head according to the present invention.

FIG. 5 is a drive explanatory diagram of one embodiment of the recording head of the present invention.

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

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

FIG. 8 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 1 Ink 2 Head substrate 3 Base plate 4 Ink chamber 5 Upper cover 6 Base substrate 7 Discharge electrode 8 Electrode pad 9 Conductor 10 Ink supply port 11 Discharge opening 12 Channel 13 Dicing blade 14 Mask 15 Conductive layer 16 Coating material 17 Recording paper 18 Counter electrode 19 Meniscus 20 Corner part 21 Ink drop 22 Line of electric force 23 Electrophoresis electrode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadashi Mizoguchi 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 Hitoshi Takemoto 7546 Yasuda, Kashiwazaki City, Niigata Prefecture Inside Niigata Nippon Electric Co., Ltd. (72) Inventor Yoshihiro Hagiwara 7546 Yasuda Oaza, Kashiwazaki City, Niigata Prefecture Niigata Nippon Electric Co., Ltd. 7546 Yasuda, Kashiwazaki, Niigata Prefecture Niigata Nippon Electric Co., Ltd.

Claims (5)

[Claims] 1. An electrostatic ink jet recording head for applying an electric field to an ink in which charged toner particles are dispersed, discharging the toner particles by an electrostatic force generated by the electric field, and performing printing, processing the ink into an uneven shape. A head substrate in which a discharge electrode made of a conductive material is formed on one of both walls and a bottom surface of each recess of a base substrate made of an insulating material, and an electrode pad respectively connected to the discharge electrode. A base plate for fixing the head substrate at a desired position, and a base plate formed above the base plate, a part of which is disposed at a position receded from the concave / convex portion of the head substrate on the tip side of the discharge electrode; And an upper cover forming an ink chamber for holding the ink. Recording head. 2. The method according to claim 1, wherein an interval between the convex portion and the concave portion of the head substrate is regularly formed at an interval of a desired resolution.
2. The electrostatic ink jet recording head according to claim 1, wherein the discharge electrodes independent of each other are formed on both walls and the bottom surface of each concave portion at the same interval as the concave portion. 3. The electrostatic ink jet recording head according to claim 1, wherein the uneven surface of the head substrate on which the discharge electrodes are formed is coated with an insulating coating material. 4. In a cross section of the concave portion of the head substrate,
The electrostatic type according to claim 1, 2 or 3, wherein the width of the concave portion is such that a capillary force can be generated, and the depth of the concave portion is formed to be deeper than the width of the concave portion. Ink jet recording head. 5. An electrophoretic electrode for applying a certain bias voltage to said ink in said ink chamber, said electrophoretic electrode being arranged to be electrically connected to said ink in said ink chamber. The electrostatic ink jet recording head according to 1, 2, 3, or 4.