JP2000025235A - Ejection head for electrostatic liquid toner jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply/discharge liquid toner smoothly by forming meniscus of toner on the surface of an ejection protrusion and flying charged coloring particles from the ejection protrusion with Coulomb force generated at a recording electrode part. SOLUTION: An ejection head of an electrostatic liquid toner jet printer comprises 16 ejection protrusions 1 arranged in four rows longitudinally and laterally. A toner supply path 12 is provided under each ejection protrusion 1 and liquid toner TN springing out from each spring hole through the toner supply path 12 wets the surface of each ejection protrusion 1 to form a truncated conical meniscus. A Coulomb force is then generated by applying a bias voltage of same polarity as charged coloring particles P to each terminal 11 under that state in order to separate the charged coloring particles P as a drop 23 being flied from each ejection protrusion 1 toward a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ejection head of an electrostatic liquid toner jet printer that prints characters and images on a recording medium by flying a liquid toner, in which charged colored particles are dispersed, by electrostatic force. .

[0002]

2. Description of the Related Art In recent years, as an output device of a personal computer, an ink jet recording type printer which forms a character or an image on a recording paper by ejecting ink particles toward a recording medium such as a recording paper opposed thereto has been widely used. ing. Among them, an electrostatic liquid toner jet printer that uses a liquid toner in which charged colored particles are dispersed in an insulating liquid and ejects the charged colored particles onto recording paper by electrostatic force to perform recording is attracting attention. Have been. The reason for this is that a bubble jet recording apparatus that ejects liquid toner from a nozzle due to thermal expansion of a bubble or a bubble jet recording apparatus that ejects liquid toner from a nozzle using a piezo pump is a problem that causes nozzle clogging. Not only must be used, but also a large number of nozzles having different inner diameters must be prepared in order to provide light and shade (gradation) of recording, whereas the electrostatic recording apparatus does not require nozzles. In addition, shading can be easily realized only by changing the voltage pulse width and the pulse height.

The ejection head of this electrostatic type jet printer is disclosed in, for example, Japanese Patent Application Laid-Open Nos.
No. 207307 and JP-A-9-207355, a liquid toner formed by dispersing charged colored particles is supplied to an emission point of an electrode having a sharp tip, and the charged colored particles are supplied to the electrode. A voltage of the same polarity is applied, and colored particles are ejected and recorded by Coulomb force generated at that time. In order to form an image, a bias voltage for aggregating the charged colorant particles at the ejection point is applied to the electrodes, and recording is performed by applying a pulsed ejection voltage to the electrodes in accordance with an image input signal. This electrostatic liquid toner jet method enables high-density printing by aggregating and ejecting charged colored particles, and the structure of the electrostatic liquid toner jet printer is relatively simple. It has the feature that high-speed printing can be easily performed.

[0004]

The ejection head of this type of conventional electrostatic liquid toner jet printer can perform high-speed printing to some extent, however, the conventional printer head as described above is used. However, the supply method of the liquid toner for each injection point is not sufficiently considered, and therefore, when high-speed printing or the like is performed, the supply of the liquid toner is not in time and characters and images are blurred. Or, there was a case where shading unevenness occurred in this. The present invention focuses on the above problems, and has been conceived to effectively solve the problems. The purpose of the present invention is to smoothly supply and discharge the liquid toner to achieve high-speed printing at a stable density. It is an object of the present invention to provide an ejection head for an electrostatic liquid toner jet printer which is made possible.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made to solve the above-mentioned problems by providing a plurality of ejection projections made of a dielectric and having a sharp tip, and a liquid toner containing charged colored particles. A groove-shaped canal provided around each of the ejection protrusions, a substrate portion having a recording electrode portion disposed substantially below the ejection protrusions, and the liquid toner formed in the substrate portion and applying the liquid toner to the canal. A liquid toner supply path for supply;
A toner discharge path formed in the substrate and discharging the liquid toner from the canal with respect to the canal,
Forming a meniscus of the toner on the surface of the ejection projection, the charged coloring particles are separated from the ejection projection by Coulomb force generated when a voltage having the same polarity as the charged coloring particles is applied to the recording electrode portion. It is designed to fly toward a recording medium.

[0006] Thus, the liquid toner containing the charged colored particles is sufficiently supplied to the canal of each of the ejection projections via the liquid toner supply path provided inside the substrate portion, and a meniscus is formed stably. . The liquid toner that has been used after being ejected is discharged via a toner discharge path also provided inside the substrate section. As a result, the liquid toner can be stably supplied to the ejection projection, so that high-speed printing or the like can be performed in a state where the density is stable.

In this case, the toner supply path is communicated with the canal through a well formed in the thickness direction of the substrate portion, and the toner discharge path is formed in the canal in the thickness direction of the substrate portion. It is communicated through the absorption hole. The spring holes and the absorption holes are respectively arranged for each of the canals. This makes it possible to more stably supply the liquid toner to each ejection protrusion.

The substrate may be formed by a printed wiring board on which the recording electrode is formed, and a resin laminate formed by laminating a plurality of photosensitive resin layers.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an ejection head of an electrostatic liquid toner jet printer according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing an embodiment of the ejection head of the electrostatic liquid toner jet printer of the present invention, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is BB in FIG.
FIG. 4 is an explanatory view for explaining a method of forming a discharge hole or an absorption hole in the structure shown in FIG. 3, and FIG. 5 is a view showing a state in which a meniscus of liquid toner is formed on an ejection protrusion. FIG.

As shown in FIG. 1, the ejection head PR of this electrostatic liquid toner jet printer is configured as a multi-head by arranging a large number of ejection projections 1 vertically and horizontally. In the illustrated example, four ejection rows 1 are arranged vertically and four rows horizontally, and a total of 16 ejection projections 1 are shown. However, actually more ejection projections 1 are formed. As will be described later, each ejection protrusion 1 serves as an ejection point, from which a droplet of the liquid toner is ejected. Each injection projection 1 is formed in a substantially conical shape as shown in FIG. 2, and the upper end is formed into a flat surface or a curved surface having a small area. Around the bottom of each of the projections 1, there is formed, for example, a mesh-like groove-shaped canal 2 surrounding the projection, along which a liquid toner TN containing charged colored particles (see FIG. 5) is applied. It is designed to shed.
The lands 3 are arranged in an island shape between the adjacent ejection projections 1 so that the liquid toner can smoothly flow into the canal 2 by utilizing a capillary phenomenon.

The injection projection plate 4 (see FIG. 2) including the injection projections 1 and the lands 3 can be formed by, for example, hot pressing using a thermoplastic resin sheet. It is set to about 5 mm. A substrate portion 5 is joined to the lower surface of the injection projection plate 4, and the substrate portion 5 is formed of a resin laminate 7 in which a printed wiring board 6 and a plurality of photosensitive resin layers are laminated. In FIG. 2, the structure of the resin layer 7 is schematically shown. The printed wiring board 6 is made of, for example, a double-sided board, and has a recording electrode portion, that is, a driving electrode 8 which is patterned in a circular shape corresponding to a position below each of the ejection protrusions 1 on the upper surface. Each drive electrode 8 is connected to a pattern wiring 10 on the back surface through a through hole 9. The pattern wiring 10 is connected to different individual terminals 11,
A drive voltage is individually applied to each of them. The bias voltage is applied to each terminal in common.

In the illustrated example, the resin laminate 7 is
For example, it is formed by laminating five photosensitive resin layers 7A to 7E. In the resin laminate 7, a toner supply path 12 for flowing unused liquid toner is formed, and a toner discharge path 13 for discharging used liquid toner is provided. In FIG. 3, a closed toner supply path 12 is provided in the second resin layer 7B from the bottom,
Closed toner discharge path 1 is connected to fifth resin layer 7D from the bottom.
3 are provided. Each of the resin layers 7A to 7E can be formed with high precision by using a photolithography method in which a process of coating a photosensitive resin and exposing it in a predetermined pattern is repeated as described above.

A well hole 14 is provided in the thickness direction of the resin laminate 7 so as to communicate the toner supply path 12 with the canal 2 of each of the injection projections 1. An absorption hole 15 penetrated in the thickness direction of the resin laminate 7 so as to communicate with the canal 2 of each injection protrusion 1.
Is provided. Specifically, as shown in FIG. 1, the toner supply paths 12 and the toner discharge paths 13 extend diagonally and are alternately arranged. Is provided. That is, the discharge holes 14 are arranged along the toner supply path 12, and the absorption holes 15 are arranged along the toner discharge path 13. Therefore, the spouting hole 14 and the absorbing hole 15 are provided in each of the two emission protrusions 1 at a ratio of one.

When the injection projection 3 is formed, for example, a thermoplastic plastic sheet and a substrate portion 5 on which drive electrodes and the like are patterned in advance are formed by pressing under pressure in a heated state. Since there is a possibility that the molten plastic may enter the spring holes 14 and the absorption holes 15, the printed wiring board 6 on the upper surface of the resin laminate 7 is left without any holes at the time of compression molding, and after thermocompression as shown in FIG. A hole may be formed in the printed wiring board 6 using a laser beam 20 or a fine drill 21 so that the lower-layer well 14 or the absorbing hole 15 communicates with the canal 24 on the upper surface.

Next, the operation of the injection head configured as described above will be described. First, an unused liquid toner TN is gradually and pressurized and fed to each toner supply path 12 at a constant pressure, and each toner discharge path 13 is set to a constant negative pressure state to use a used liquid. The toner has been sucked and discharged. The collected liquid toner is preferably circulated. As shown in FIG. 5, the liquid toner TN spouted from the spout holes 14 through the toner supply passage 12 fills the respective canals 2 and wets the surfaces of the respective ejection protrusions 1 by capillary action to form a truncated conical meniscus 22. Put up. In this state, when a bias voltage having the same polarity as that of the charged colored particles P is applied to each terminal 11, the charged colored particles P are pressed on the top of the meniscus 22 by the electric field generated by the drive electrode 8 and aggregated. This colored particle P
The top of the meniscus 22 swells due to the balance between the force separating from the drive electrode 8 and the surface tension of the liquid toner solvent.

Here, for example, when a predetermined driving voltage is further superimposed on the bias voltage at the specific driving electrode 11A, the top of the meniscus 22 receives further force, and finally cuts off to become the drop 12, which is further accelerated by the electric field, flies, and flies. When the recording medium collides with a recording medium (not shown) placed on the recording medium, the recording medium is attached and dots are recorded. After the colored particles P are agglomerated and blown off, the density of the colored particles P decreases and liquid toner having a high solvent ratio remains. The remainder is absorbed by the absorption hole 15 and returned to the liquid toner storage tank (not shown) via the toner discharge path 13. In this way, the remaining colored particles and the solvent are collected in the liquid toner storage tank. The density of the colored particles in the liquid toner in the storage tank also decreases over time, but the tank capacity is generally large, so the reduction in print density due to this reduction can be ignored, and new toner can be replenished as necessary. I do.

As described above, one spout hole 14 and one absorption hole 15 are arranged for each canal 2 of each ejection projection 1, and the liquid toner TN is directly supplied to each canal 2 via the toner supply path 12. The liquid toner TN smoothly.
Can be supplied. Therefore, even when high-speed printing is performed, the liquid toner TN can be replenished immediately, and high-speed printing or the like can be performed each time the density is stable. Further, since the used liquid toner TN is immediately discharged from the absorption hole 15, no problem occurs. In addition, since the ejection projection plate 4 is not formed except for the ejection projection 1, the canal 2, and the land 3, the ejection projection 1 can be arranged in a high density state, and high density recording can be achieved.

[0018]

As described above, according to the ejection head of the electrostatic liquid toner jet printer of the present invention, the following excellent operational effects can be exhibited. Since the toner supply path and the toner discharge path are provided, the liquid toner can be smoothly and quickly supplied to the canal of each ejection protrusion.
High-speed printing and the like can be stably performed at a stable density.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of an ejection head of an electrostatic liquid toner jet printer of the present invention.

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

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

FIG. 4 is an explanatory diagram for explaining a method for forming a spring hole and an absorption hole in the structure shown in FIG. 3;

FIG. 5 is a diagram illustrating a state in which a meniscus of liquid toner is formed on an ejection protrusion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Injection protrusion, 2 ... Canal, 3 ... Land, 4 ... Injection protrusion plate, 5 ... Board part, 6 ... Printed wiring board, 7 ... Resin laminate, 7A-7E ... Resin layer, 8 ... Drive electrode (recording electrode) 12) Toner supply path, 13: discharge path, 14: discharge hole, 15: absorption hole, 22: meniscus, 23: drop, P: charged colored particles, PR: ejection head, TN: liquid toner.

Claims (4)

[Claims] A plurality of injection projections each having a sharp tip made of a dielectric; a groove-shaped canal provided around each of the injection projections for flowing a liquid toner containing charged colored particles; A substrate portion having a recording electrode portion disposed substantially below the protrusion, a liquid toner supply path formed in the substrate portion and supplying the liquid toner to the canal;
A toner discharge path formed in the substrate and discharging the liquid toner from the canal with respect to the canal,
Forming a meniscus of the toner on the surface of the ejection projection, the charged coloring particles are separated from the ejection projection by Coulomb force generated when a voltage having the same polarity as the charged coloring particles is applied to the recording electrode portion. An ejection head for an electrostatic liquid toner jet printer, wherein the ejection head is designed to fly toward a recording medium. 2. The toner supply path is communicated with the canal through a spring hole formed in a thickness direction of the substrate portion,
2. The ejection head according to claim 1, wherein the toner discharge path communicates with the canal via an absorption hole formed in a thickness direction of the substrate. 3. The spout hole and the absorption hole are arranged for each of the canals.
The injection head of the electrostatic liquid toner jet printer according to the above. 4. The printed circuit board according to claim 1, wherein the printed circuit board is formed with a plurality of photosensitive resin layers. 3. The ejection head of the electrostatic liquid toner jet printer according to any one of 3.