JP2842326B2 - 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 discharging an individual charged toner contained in liquid ink by the action of an electric field.

[0002]

2. Description of the Related Art Heretofore, there has been an electrostatic ink jet recording head which applies an electric field to a charged liquid ink and causes the charged ink to fly on a recording paper to directly perform recording.

[0003]

However, in the above-mentioned conventional example, since the recording is performed by directly adhering the liquid ink to the recording paper, bleeding occurs in the printing and there is a certain limit to the improvement of the recording resolution. There was an inconvenience.

On the other hand, in recent years, a new type of ink in which solid charged toner is contained in liquid ink has been developed, and a new type of electrostatic ink jet recording head and apparatus for recording by flying the charged toner in the ink by an electric field. Is being developed.

However, how to reduce the size of the apparatus, how to effectively discharge the charged toner in the liquid ink, how to improve the discharge direction accuracy, how to realize high-speed printing, and the like. Various issues remain.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art.
It is an object of the present invention to provide an electrostatic ink jet recording head capable of performing high-speed, high-print-quality recording equivalent to an electrophotographic system.

[0007]

According to the first aspect of the present invention, there is provided an ink flow path having an ink chamber at one end for storing ink containing charged toner and an ink outlet at the other end communicating with the outside. An ejection portion forming member that forms an outer contour of the ink flow path, and ejection electrodes that are provided along with the ejection portion forming member and generate an electric field for ink ejection are provided. Further, the ink ejection surface of the ejection portion forming member is formed to be sharp in a V shape, and the ink outlet is set to be aligned with the V-shaped tip of the ink ejection surface. V-shaped tip
And arranged substantially at the center of the V-shaped ink ejection surface.

In the present invention, a thin film-like ink meniscus is formed at the tip of the ink ejection surface, and when an ejection pulse is applied to the ejection electrode, the ink is charged almost at the center of the ink ejection surface where the tip of the ejection electrode is arranged. The toner concentrates, and the toner group flies from the center toward the counter electrode.

The invention according to claim 2 adopts a configuration in which the ink flow path and the discharge portion forming member are provided on the front surface of the substrate, and the connection end of the discharge electrode is provided on the back surface of the substrate.

In the present invention, the components on the front surface of the substrate and the connection ends of the discharge electrodes provided on the rear surface of the substrate are arranged at positions where they overlap.

According to the third aspect of the present invention, the substrate and the discharge portion forming member are formed integrally by a green sheet hole forming method.

In the present invention, necessary pattern printing is performed on a base green sheet, and then the next green sheet is laminated. Then, after performing binder removal processing, main sintering is performed, whereby the ceramic green sheet is hardened and unnecessary pattern printed portions are removed. Then, by repeating this process, the substrate and the discharge portion forming member are integrally formed.

According to a fourth aspect of the present invention, two electrostatic ink jet recording heads according to the second aspect are provided such that the back surface of the substrate faces the back surface, and the ink ejection surface of one and the other recording heads. Are set in the same direction, and the arrangement positions of the ink ejection surfaces are set so as to alternate between one print head and the other print head.

In the present invention, the toner group is selectively discharged from the doubled ink discharge surface.

[0015] With the above, the above-mentioned object is achieved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

The electrostatic ink jet recording head shown in FIGS. 1 to 3 has an ink chamber 10 for storing ink I containing charged toner at one end and an ink outlet 4 communicating with the outside.
An ink flow path 1 having at the other end thereof, a discharge section forming member 5b forming an outer contour of the ink flow path 1, and a discharge section forming member 5
b and an ejection electrode 3 for generating an electric field for ink ejection. Further, the ink ejection surface 2 of the ejection portion forming member 5b is formed to be sharp in a V-shape. Further, the ink outlet 4 is set to be aligned with the V-shaped tip of the ink ejection surface 2. Further, the tip of the ejection electrode 3 is arranged substantially at the center of the V-shaped ink ejection surface 2.

In this embodiment, the ink flow path 1
The discharge section forming member 5b is provided on the surface of the substrate 5a. On the other hand, the connection end of the ejection electrode 3 is provided on the back surface of the substrate 5a. Further, the substrate 5a and the discharge portion forming member 5b are integrally formed by a green sheet hole forming method to form a discharge cell 5.

More specifically, in this embodiment, the discharge portion forming member 5b is provided in parallel with the surface of the substrate 5a.
And two sets of ink flow paths 1 and 1 and ink outlets 4 and 4 are provided. Each ink flow path 1 is connected to a single ink chamber 10. The ejection part forming member 5b is
The main body is formed in a rectangular shape, and its ink ejection surface 2 is
Are pointed in a V-shape in the horizontal direction. The ink ejection surface 2 of the ejection portion forming member 5b is set at a position slightly retreated from the tip of the substrate 5a. Here, the ejection portion forming member 5b is arranged at intervals of 300 [dpi], that is, approximately 85.
They are formed at intervals of [μm].

The surface of the substrate 5a is
Thus, an ink chamber 10, an ink flow path 1, and an ink outlet 4 are formed. The tip of the ink holding member 7 is set at the same position as the tip of the ejection surface of the ejection portion forming member 5b. Further, inside the ink chamber 10, a plate-like toner transport electrode 8 is provided on the opposite side to the ink flow path 1 so as to be exposed. Two ink supply ports 6 and 6 are provided in a portion of the ink holding member 7 corresponding to the ink chamber 10.
Is provided. Further, on the substrate 5a between the adjacent ejection portion forming members 5b, a convex resistance portion 11 which does not block the ink flow path 1 is provided.

The three discharge electrodes 3 provided corresponding to the respective discharge portion forming members 5 b are formed in a band shape, and the tip is sharpened along the shape of the ink discharge surface 2. The ejection electrode 3 is embedded in the ejection portion forming member 5b along the longitudinal direction of the ejection portion forming member 5b, and is bent in a crank shape from the middle, and both of the ejection portion forming member 5b and the substrate 5a are via-connected. The hole penetrates through the hole, passes through the via hole, and is formed on the back surface of the substrate 5a from the rear end to the connection portion 3a with the external voltage driving unit. The connection portion 3a is formed in a pad shape and is arranged in parallel at the rear end of the back surface of the substrate 5a. The tip of the ejection electrode 3 is exposed on the ink ejection surface 2. On the other hand, the connecting portion 3a at the rear end of the ejection electrode 3
Is formed to have a width slightly smaller than the width of the discharge portion forming member 5b.

The ink supply ports 6, 6 provided in the ink holding member 7 are connected to an ink pump via tubes (not shown). This ink pump is connected to the ink chamber 10.
It has a function of energizing a negative pressure of about 1 cmH ₂ O to the ink I inside and forcibly circulating the ink I.

The ink I used for recording is obtained by dispersing thermoreversible resin fine particles (toner) colored together with a charge controlling agent in a petroleum organic solvent (isoparaffin), and the toner particles have a zeta potential. Is apparently positively charged.

The ink discharge surface 2 faces the counter electrode 12 grounded via the paper transport path 13. Furthermore,
The connection portion 3a of the ejection electrode 3 and the toner transport electrode 8 are connected to a voltage driving unit (not shown). The voltage driver has a function of applying a voltage pulse having the same polarity as the charged toner in the ink to the discharge electrode 3 during recording, and a function of constantly applying a voltage having the same polarity as the charged toner to the toner transport electrode 8. ing.

Here, a description will be given of a green sheet hole forming method for integrally forming the substrate 5a and the discharge portion forming member 5b as described above.

The green sheet is used when forming a multilayer ceramic substrate, and has the characteristics of high strength, low dielectric constant, and excellent stability of shrinkage. More specifically, via holes having a diameter of 100 [μm] can be formed at intervals of 250 [μm], and a fine pattern of 50 [μm] having high compatibility with the conductive material can be laminated with high precision. it can.

Next, the manufacturing process will be described. The necessary pattern printing is performed on a green sheet as a base, and the next green sheet is laminated. Then, after performing the binder removal process, the main sintering is performed. As a result, the ceramic green sheet is cured, and unnecessary pattern printing portions are removed. By repeating this process, an arbitrary pattern can be formed and holes can be integrally formed.

Next, the overall operation according to the above embodiment will be described.

When ink is supplied to the ink chamber 10 and penetrates the ink flow path 1, the ink I drawn from the ink outlet 4 forms a thin film-like ink meniscus on the ink ejection surface 2.

Subsequently, the entire apparatus is set in an operating state,
When a voltage having the same polarity as that of the charged toner is applied to the toner transport electrode 8, an electric field is generated due to a potential difference between the toner transport electrode 8 and the discharge electrode 3. The ink is electrophoresed near the tip of the ink meniscus through the ink outlet 4 and transported.

When a voltage pulse having the same polarity as that of the charged toner is applied to the discharge electrode 3 in this state, an electric field is generated between the tip of the discharge electrode 3 and the counter electrode 12, and the action of the electric field causes the ink meniscus. The charged toner inside is concentrated on the tip end of the discharge electrode 3, and is discharged (flies) as a toner group T toward the counter electrode 12. The discharged toner group T adheres to the recording paper disposed in front of the counter electrode 12, and is then sent to a fixing device (not shown) to be thermally fixed, thereby performing printing.

When the toner group T is ejected, the ink meniscus is vibrated, and this vibration is also transmitted to the ink in the ink flow path 1. The vibration of the ink meniscus causes an error in the direction in which the electric field is concentrated and causes an error in the flying direction of the toner group. Therefore, in the present embodiment, the vibration of the ink meniscus is suppressed by providing the resistance portion 11 in the ink flow path 1.

When the toner group T is discharged, the amount of charged toner in the ink meniscus becomes insufficient. Therefore, in the present embodiment, the shortage of the charged toner can be promptly compensated by constantly applying a voltage to the toner transport electrode 8.

Further, after the ejection of the toner group, a counter ion (the polarity opposite to that of the charged toner) is set near the ink ejection surface 2.
Occurs. The counter ions affect the direction in which the electric field is formed, and hinder the conveyance of the charged toner by electrophoresis. Therefore, in the present embodiment, the excessive counter ions in the ink are forcibly discharged by bringing the toner transport electrode 8 into direct contact with the ink.

By repeating the above operations, desired printing can be performed on the recording paper.

As described above, according to the present embodiment, it is possible to realize an electrostatic ink jet recording head that performs recording by discharging charged toner in ink.

Also, since the tip of the discharge electrode is arranged at the center of the V-shaped ink discharge surface forming the ink outlet,
A thin film-like ink meniscus can be formed on the ink ejection surface, and the toner group can be ejected from the center thereof, so that the vibration generated in the ink meniscus after ejecting the toner group can be suppressed. For,
Even when the toner group is continuously discharged, the discharge direction of the toner group can be maintained with high accuracy, and high quality printing can be performed.

Further, since the connection portion of the discharge electrode is provided on the back surface of the substrate, the connection portion and the component on the surface of the substrate can be arranged in an overlapping manner, thereby reducing the size of the substrate. Accordingly, the size of the entire recording head can be reduced.

Further, since the substrate and the discharge portion forming member can be integrally formed by the green sheet hole forming method, the manufacturing process is easy and the manufacturing cost can be reduced.

In addition, since the resistance section is formed in the ink flow path, it is possible to effectively prevent the vibration generated in the ink due to the ejection of the toner group from being transmitted to another ink flow path.

Here, the position of the tip of the recording electrode may be arranged above or below the center of the ink ejection surface. The number of ink ejection surfaces may be increased or decreased as needed. The manufacturing process may be performed by photolithography. Further, this does not prevent the connection of the discharge electrode from being arranged on the substrate surface. The toner transport electrode may be provided on a side surface of the ink chamber.

Next, another embodiment of the present invention will be described with reference to FIG.

In the electrostatic ink jet recording head shown in FIG. 4, two electrostatic ink jet recording heads shown in the first embodiment are provided so that the back surface of the substrate 5a faces the back surface, and one and the other are provided. The ink discharge surfaces 2 of the print heads are set in the same direction, and the arrangement positions of the ink discharge surfaces 2 are alternately set for one print head and the other print head. Other configurations are the same as those of the first embodiment.

In this case, the same operation and effect as those of the above embodiment can be obtained, and the recording resolution can be at least doubled. Further, the printing speed can be at least doubled.

Also, since the width of the connection portion of the discharge electrode is slightly smaller than the width of the discharge portion forming member, when two members are overlapped, the connection portions are alternately arranged, and one connection is formed. The connector part can be easily designed.

[0046]

The present invention is constructed and functions as described above. According to this, the tip of the discharge electrode is arranged at the center of the V-shaped pointed ink discharge surface forming the ink outlet, so that the ink A thin film-shaped ink meniscus can be formed on the ejection surface, and the toner group can be ejected from the center of the ink meniscus, so that the vibration generated in the ink meniscus after ejecting the toner group can be suppressed. Even when the toner group is continuously discharged, the discharge direction of the toner group can be maintained with high accuracy, and high quality printing can be performed.

According to the second aspect of the present invention, since the connection portion of the discharge electrode is provided on the back surface of the substrate, the connection portion and the component on the surface of the substrate can be arranged so as to overlap with each other. The size can be reduced,
The size of the entire recording head can be reduced.

According to the third aspect of the present invention, since the substrate and the discharge section forming member can be integrally formed by the green sheet hole forming method, the manufacturing process is easy and the manufacturing cost can be reduced.

According to the fourth aspect of the invention, since the two recording heads are arranged so that the ink ejection surfaces thereof are alternately arranged, the recording resolution can be at least doubled. Further, it is possible to provide an unprecedented excellent electrostatic ink jet recording head capable of at least doubling the printing speed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is a front view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink flow path 2 Ink discharge surface 3 Discharge electrode 3a Connection part of discharge electrode 4 Ink outlet 5a Substrate 5b Discharge part forming member 10 Ink chamber

Continuation of the front page (72) Inventor Hitoshi Minemoto 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Yoshihiro Hagiwara 7-1-1 Shiba, Minato-ku, Tokyo NEC Corporation (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/06

Claims (4)

(57) [Claims] 1. An ink flow path having an ink chamber at one end for storing ink containing charged toner at one end and an ink outlet at the other end communicating with the outside, and a discharge section forming member forming an outline of the ink flow path. In an electrostatic ink jet recording head provided with a discharge electrode for generating an electric field for ink discharge, which is provided alongside the discharge portion forming member, the ink discharge surface of the discharge portion forming member is formed in a V-shape. At the same time, the ink outlet is set so as to be aligned with the V-shaped tip of the ink ejection surface, and the tip of the ejection electrode is set in the ink ejection surface.
An electrostatic ink jet recording head, which is arranged substantially at the center of the V-shaped ink ejection surface so as to coincide with the V-shaped tip . 2. The electrostatic type according to claim 1, wherein the ink flow path and the ejection portion forming member are provided on a front surface of the substrate, and a connection end of the ejection electrode is provided on a back surface of the substrate. Ink jet recording head. 3. The electrostatic ink jet recording head according to claim 2, wherein the substrate and the discharge portion forming member are integrally formed by a green sheet hole forming method. 4. An electrostatic ink jet recording head according to claim 2, wherein two back faces of the substrate face each other, and the ink ejection faces of one and the other printing heads are in the same direction. And an arrangement position of the ink ejection surface is set alternately between the one recording head and the other recording head.