JPH1044431A - Electrostatic ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply ink smoothly even in a high speed driving flow region by providing a head board where jet electrodes are formed of independent metallic materials on the upper surface at each protrusion of a base board made of an insulating material and machined to have protrusions and recesses, and electrode pads connected with respective jet electrodes thereby reducing the channel resistance at the recess. SOLUTION: The electrostatic ink jet recording head comprises a head board 2 where a jet electrode 7 made of an independent metallic material is provided on the upper surface at each protrusion of a base board 6 made of an insulating material and machined to have protrusions and recesses, a base plate 3 secured to a desired position of the head board 2 while having electrode pads 8 connected with respective jet electrode 7, and an upper cover 5 formed above the base plate 3 while partially opening the protruding/recessed part on the forward end side of the jet electrode 7 and covering other protruding/recessed face in order to form a chamber 4 for holding an ink 1 along with the base plate 3. The head board 2 comprises the base board 6 made of an insulating material and the jet electrode 7 made of a metallic material.

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 using an ink in which toner particles are dispersed in a carrier liquid and performing recording by flying toner particles by electrostatic force. About the head.

[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. 8 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. 9 is a top view and a cross-sectional view of the 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]

A first problem is that the above-mentioned conventional electrostatic ink jet recording head cannot follow the supply of ink in a high-speed driving area. The reason is that since the photosensitive resist material is used as the meniscus forming member, the thickness is several tens μm.
And the flow resistance of the discharge opening increases due to the thickness of the meniscus forming member.

[0008] The second problem is that a stable meniscus shape cannot be obtained. 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 loose shape. Another reason is that the tip of the meniscus forming member is formed at a position retreated from the end surface of the substrate.

SUMMARY OF THE INVENTION An 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 ejects 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, a head substrate in which ejection electrodes made of independent metal materials are formed on the upper surfaces of the respective protrusions of a base substrate made of an insulating material processed into an uneven shape, and A base plate having electrode pads respectively connected to the ejection electrodes and fixing the head substrate at a desired position; and a top plate formed on the base plate and partially having irregularities on the tip side of the ejection electrodes of the head substrate. And an ink chamber which is disposed so as to release a portion and cover an upper portion of another uneven surface, and further holds the ink together with the base plate. And a upper cover forming a.

Further, in the electrostatic ink jet recording head of 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. The independent discharge electrodes are formed at the same intervals as the projections.

Further, in the electrostatic ink jet recording head of the present invention, the concave portion of the head substrate functions as a flow path for supplying the ink containing the toner particles to the convex end face on the tip end side of the discharge electrode. It is characterized by the following.

Further, the electrostatic ink jet recording head of 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 greater than the width of the concave portion. It is characterized by being formed so that it becomes. The concave portion of the head substrate is formed by dicing.

Further, the electrostatic ink jet recording head according to the present invention is characterized in that the concave portions of the head substrate are collectively formed by laser processing.

Further, in the electrostatic ink jet recording head according to the present invention, the base substrate of the head substrate is made of a photosensitive insulating material, and the concave portions are collectively formed by photolithography. I do.

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

[0018]

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

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention, and FIG.
(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 an ink 1 in which charged toner particles are dispersed,
An electrostatic ink jet recording head that performs printing by discharging toner particles by electrostatic force generated by this electric field, wherein an independent metal is provided on the upper surface of each convex portion of a base substrate 6 made of an insulating material processed into an uneven shape. A head substrate 2 on which discharge electrodes 7 made of a material are formed; a base plate 3 having electrode pads 8 connected to the respective discharge electrodes 7 and fixing the head substrate 2 at a desired position; An ink chamber 4, which is arranged on the upper part and is partially disposed so as to release the uneven part on the tip side of the discharge electrode 7 of the head substrate 2 and cover the upper part of the other uneven surface; And an upper cover 5 that forms

The head substrate 2 includes a base substrate 6 made of an insulating material such as glass, and an ejection electrode 7 made of a metal material such as Ni or Cu. The surface of the base substrate 6 is processed into a concavo-convex shape so that each concave portion and convex portion are formed at the same interval as the desired resolution, and an independent discharge electrode 7 is provided on the upper surface of each convex portion with the desired resolution. It is formed at the same interval as. Each recess is provided with ink 1 to each ejection electrode 7.
And holds the ink 1 while forming a meniscus in each concave portion.

The base plate 3 is made of an insulating material. On the surface of the base plate 3, electrode pads 8 for contacting a drive driver (not shown) and a drive voltage input from each electrode pad 8 are applied to each discharge electrode 7. A conductor 9 for supplying is formed. Also, base plate 3
Is fixed at a desired position along the end face of the head substrate 2 such that the end of the head substrate 2 on the tip end side of the ejection electrode 7 faces the outside of the base plate 3. One end of each ejection electrode 7 and each conductor 9 are connected by wire bonding. And so on.
It is preferable that the connection between the discharge electrode 7 and the conductor 9 and each conductor 9 are coated and sealed with an insulating resin.

The upper cover 5 is made of an insulating material made of a plastic molded product, and forms an ink chamber 4 that is disposed above the base plate 3 and holds 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 discharge port (not shown) for discharging the ink 1 from the ink chamber 4 are formed at an upper portion of the upper cover 5. The port 10 and the ink discharge port are connected to an ink circulation pump (not shown) and an ink tank via a tube. In addition, a part of the upper cover 5 is disposed on the upper part of the head substrate 2 to release an uneven surface end surface on the tip side of the discharge electrode 7 and cover an upper portion of another uneven surface.
A discharge opening for supplying the ink 1 from the ink chamber 4 to each discharge electrode 7 is formed together with the concave portion of the head substrate 2.

FIG. 2 is a view showing a process of manufacturing a discharge electrode on a head substrate according to this embodiment. Referring to FIG. 2, Cu, Cu, and the like are formed on the entire surface of the base substrate 6 made of a flat insulating material.
Conductive layer 11 by depositing a metal material such as Ni by sputtering.
Is formed (FIG. 2A). Next, a resist layer 12 made of a photosensitive resist material is formed on the conductor layer 11 by spin coating or lamination (FIG. 2B). Next, by exposing and developing through a mask 13 on which the pattern of the ejection electrodes 7 is formed (FIG. 2C), a portion where a plurality of independent ejection electrodes 7 arranged at intervals of a desired resolution is formed. Only the resist layer 12 is left (FIG. 2)
(D)). Next, the base substrate 6 on which the conductor layer 11 and the resist layer 12 are formed is immersed in an etchant that erodes only the conductor layer 11, and the portion of the conductor layer 11 where the resist layer 12 is not formed is removed ( FIG. 2 (e)). Finally, the base substrate 6 in which the conductor layer 11 and the resist layer 12 are left in the pattern of the discharge electrode 7 is removed from the resist layer 12.
Only the head substrate 2 on which a plurality of independent ejection electrodes 7 arranged at intervals of a desired resolution is obtained by immersing only the etching solution in the etching solution which erodes and removing the resist layer 12 (FIG. 2 (f) )). The head substrate 2
Alternatively, a plurality of head substrates 2 may be collectively formed on a single wafer-shaped base substrate 6 by the above-described manufacturing method, and then the wafer may be cut and obtained as individual head substrates 2.

FIG. 3 is a diagram showing a concavo-convex shape formed by dicing the head substrate of this embodiment. Referring to FIG. 3, the head substrate 2 (FIG. 3) manufactured by the process of FIG.
A dicing blade 14 is provided between the discharge electrodes 7 in FIG.
The surface of the head substrate 2 is formed in an uneven shape by dicing with a desired cut amount using
(B)). Further, in order to insulate each ejection electrode 7 from the ink 1, the ejection electrode 7 is covered with an insulating coating material 15 (FIG. 3C).

FIG. 4 is a diagram showing a concavo-convex shape formed by laser processing of the head substrate of this embodiment. Referring to FIG. 4, the head substrate 2 (FIG. 4) manufactured by the process of FIG.
By irradiating a laser beam such as an excimer laser between the ejection electrodes 7 of FIG.
The surface of the head substrate 2 is formed in an uneven shape (FIG. 4)
(B)). The depth of the concave portion can be arbitrarily set by adjusting the irradiation time of the laser beam. Further, in order to insulate each ejection electrode 7 from the ink 1, it is coated with an insulating coating material 15 (FIG. 4).
(C)).

FIG. 5 is a diagram showing the formation of a concavo-convex shape of the head substrate of this embodiment by photolithography. Referring to FIG. 5, a mask 17 having a pattern in which a portion where a concave portion is formed is formed between each discharge electrode 7 of the head substrate 2 (FIG. 5A) manufactured by the process of FIG.
The surface of the head substrate 2 is formed in an uneven shape by exposing and developing through (FIG. 5B). The depth of the concave portion can be arbitrarily set by adjusting the etching time at the time of development. Further, in order to insulate each ejection electrode 7 from the ink 1, it is coated with an insulating coating material 15 (FIG. 5C).

FIG. 6 is a schematic driving diagram of the recording head of this embodiment. In the recording head of this embodiment, the end of the head substrate 2 on the tip end side of the discharge electrode 7 faces the opposing electrode 18 whose surface also serves as a platen for transporting the recording paper 19 and has a potential of 0 V or a negative potential. It is arranged in the direction to do. Further, at the end of the head substrate 2 on the tip end side of the discharge electrode 7, the corner of the protrusion is disposed so as to be closest to the counter electrode 18. A minute discharge gap is provided between them. The recording paper 19 includes a recording head and a counter electrode 18.
The paper is fed along the discharge gap between the opposite electrodes 18. When the ink droplet 20 is ejected, a drive pulse voltage is applied to a desired ejection electrode 7 and the ejection electrode 7 and the counter electrode 18 are applied.
When an electric field is generated between the two, an electrostatic force acts on the ink 1 containing the toner particles, and the ink droplets containing the toner particles are used as ejection points at the corners of the convex portions where the driven ejection electrodes 7 are formed. 20 is ejected toward the recording paper 19 on the counter electrode 18 to perform printing.

FIG. 7 is a schematic diagram of an electrostatic ink jet recording head according to another embodiment. In this embodiment, in addition to the configuration of the embodiment of FIG.
An electrophoresis electrode 21 in contact with the ink 1 is provided therein. A voltage having the same polarity as the potential of the toner is applied to the migration electrode 21 to generate toner particles in the ink 1 supplied from the ink supply port 10 to the ink chamber 4 between the migration electrode 21 and a counter electrode (not shown). The toner particles are conveyed to the vicinity of the discharge electrode 7 by utilizing the electrophoresis phenomenon of the toner particles by the electric field.

[0029]

The first effect is that the electrostatic ink jet recording head of this embodiment can follow the supply of ink even in a high-speed driving area. The reason is that the concave portion functioning as a flow path for supplying ink to the ejection point can be processed to an arbitrary depth by forming the concave and convex shape on the surface of the head substrate using the present manufacturing process. This is because the flow path resistance of the above becomes small.

The second effect is that a stable meniscus shape at the discharge point can be obtained.
The reason is that the end surface of the concave / convex surface on which the meniscus of the ink is formed is formed on the end surface of the head substrate.

[Brief description of the drawings]

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

FIG. 2 is a view showing a process of manufacturing a discharge electrode on a head substrate according to the embodiment.

FIG. 3 is a diagram showing a concavo-convex shape formed by dicing the head substrate of this embodiment.

FIG. 4 is a diagram showing a concavo-convex shape formed by laser processing of the head substrate of this embodiment.

FIG. 5 is a diagram showing a concavo-convex shape of the head substrate of this embodiment by photolithography.

FIG. 6 is a schematic driving diagram of an example of the recording head according to the embodiment.

FIG. 7 is a schematic diagram of an electrostatic ink jet recording head according to another embodiment.

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

FIG. 9 is a top 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 ejection electrode 8 electrode pad 9 conductor 10 ink supply port 11 conductor layer 12 resist layer 13, 16, 17 mask 14 dicing blade 15 coating material 18 counter electrode 19 Recording paper 20 Ink drop 21 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 (9)

[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 discharge electrodes made of independent metal materials are formed on the upper surfaces of the respective protrusions of a base substrate made of an insulating material, and an electrode pad connected to each of the discharge electrodes. A base plate fixed at a desired position; and a portion formed above the base plate and partially disposed so as to release the uneven portion on the tip end side of the discharge electrode of the head substrate and cover another upper portion of the uneven surface. And an upper cover forming an ink chamber in which the ink is held together with the base plate. Ink jet 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.
The discharge electrodes which are independent of each other are formed on the upper surface of each projection at the same interval as the projection.
The electrostatic ink jet recording head according to the above. 3. The method according to claim 1, wherein the concave portion of the head substrate functions as a flow path for supplying the ink containing the toner particles to a convex end surface on the tip side of the discharge electrode. Electrostatic ink jet recording head. 4. The electrostatic ink jet recording 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. head. 5. A cross section of the recess of the head substrate, wherein the recess has a width such that a capillary force can be generated, and the depth of the recess is formed to be greater than the width of the recess. The electrostatic ink jet recording head according to claim 1, 2, 3, or 4. 6. The electrostatic ink jet recording head according to claim 1, wherein the concave portions of the head substrate are formed by dicing, respectively. 7. The electrostatic ink jet recording head according to claim 1, wherein the concave portions of the head substrate are formed collectively by laser processing. 8. The method according to claim 1, wherein the base substrate of the head substrate is made of a photosensitive insulating material, and the concave portions are collectively formed by a photolithography technique. 6. The electrostatic ink jet recording head according to 5. 9. The electrophoretic electrode for applying a certain bias voltage to the ink in the ink chamber is provided so as to be electrically connected to the ink in the ink chamber. 1,2,3,4,5
9. The electrostatic ink jet recording head according to 6, 7, or 8.