JPH09109438A - Printing head in powder jet image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing head for a powder jet image forming device capable of obtaining high image density and printing at high speed. SOLUTION: The printing head includes the main part of each first electrode 21 comprising parallel electrodes 21a, 21b arranged at given distances, a groove 24 formed along the part between the parallel electrodes 21a, 21b of the first electrode 21 on the surface of an insulation layer 20 with each first electrode 21 formed therein, and a developer insertion hole 23 communicating from the surface of the second electrode 22 to the groove 24 of the insulation layer 20 at the groove 24 bottom wall of the insulation layer 20 and the second electrode 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head in a powder jet image forming apparatus.

[0002]

2. Description of the Related Art First, the basic structure of a powder jet image forming apparatus will be described with reference to FIG. In the powder jet image forming apparatus, the recording paper P is guided by the guide plate 5, and the base roller (base electrode) 3,
It is discharged through the fixing roller 4. The print head 2 is disposed below the base roller 3.

Toner is supplied to the print head 2 from a toner supply unit 10. The toner is assumed to be negatively charged in this example.

The toner supply unit 10 comprises a casing 11 filled with toner, a stirring pad 6 rotatably arranged in the casing 11, and a toner supply roller 1 rotatably arranged in the casing 11. . Stirring pad 6
The toner supply roller 1 is driven to rotate in a predetermined direction by a motor (not shown).

As shown in FIGS. 6 and 7, the print head 2 includes an insulating substrate (insulating layer) 20 and a plurality of first electrodes 21 formed on the surface of the insulating substrate 20 on the toner supply roller 1 side.
And a plurality of second electrodes 22 formed on the surface of the insulating substrate 20 on the base roller 3 side. Multiple first electrodes 2
The one and the plurality of second electrodes 22 form a matrix electrode. Each first electrode 21 and each second electrode 22
A toner insertion hole 23 penetrating the print head 2 is formed at each intersection position of and.

The print head 2 is provided with an ultrasonic vibrator 50 for applying ultrasonic vibration to the print head 2 to prevent the toner insertion hole 23 from being clogged with toner.

The recording paper P is moved by the base roller 3 in a direction orthogonal to the first electrode 21 (direction shown by arrow A in FIG. 5).
Transported to

An on-voltage (for example -100V) and an off-voltage (for example + 300V) are selectively applied to each first electrode 21. Each second electrode 22 has an on-voltage (for example, 0 V) and an off-voltage (for example, -200 V).
V) and are selectively applied.

FIG. 8 shows the applied voltage V1- to each first electrode 21.
The change of 1-V1-8 is shown. As shown in FIG.
Dynamic scanning control is applied to each first electrode 21, and the applied voltage is sequentially turned on at predetermined unit time intervals. Then, only when the applied voltage to both the first electrode 21 and the second electrode 22 is the on-voltage, the toner insertion hole 23 at the intersection thereof is applied.
The toner passes through and dot printing is performed.

For example, 0V is applied to the toner supply roller 1.
And a binary periodic voltage of 150 V is applied. A voltage of +200 V, for example, is applied to the base roller 3.

In the above powder jet image forming apparatus, the toner is supplied from the toner supply roller 1 side to the first electrode 21 by the electric field between the toner supply roller 1 and the first electrode 21. Then, as shown in FIG. 9, due to the electric field between the first electrode 21 and the second electrode 22, the toner accumulated on the first electrode 21 passes through the toner insertion hole 23 and is transferred onto the recording paper. It

[0012]

By the way, in the Pavdar jet image forming apparatus, when the printing speed is increased, the printing time per dot is shortened. Therefore, there is a problem that the amount of toner passing through the toner insertion hole becomes small and a sufficient image density cannot be obtained.

An object of the present invention is to provide a print head in a powder jet image forming apparatus which can obtain high image density and can perform high speed printing.

[0014]

A print head in a powder jet image forming apparatus according to the present invention comprises a plurality of first electrodes formed on the surface of a developer supplying portion of an insulating layer, and a recording paper conveying of the insulating layer. In a print head in a powder jet image forming apparatus in which a matrix-shaped electrode portion is formed by a plurality of second electrodes formed on the surface of the first portion, a main portion of each first electrode is arranged at a predetermined interval. And a groove is formed along the portion between the parallel electrode portions of the first electrode on the surface of the insulating layer on which the first electrode is formed. At the intersection of the second electrode, at the bottom wall of the groove of the insulating layer and the second electrode,
A developer insertion hole communicating from the surface of the second electrode to the groove of the insulating layer is formed.

In the conventional print head, as shown in FIG. 9, among the developers accumulated on the first electrode, only the developer near the opening of the developer insertion hole formed on the first electrode is used. Although it cannot pass through the insertion hole, in the print head according to the present invention, as shown in FIG. 4, most of the developer accumulated on the first electrode can pass through the developer insertion hole through the groove of the insulating layer. , High image density can be obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

1 to 3 are partial enlarged views of the print head.

This print head is similar to the print head described with reference to FIGS. 5 to 7, and has the insulating layer 20, the first electrode 21 formed on one side of the insulating layer 20, and the other surface of the insulating layer 20. And the formed second electrode 22.

The main part of each first electrode 21 is composed of parallel electrode parts 21a and 21b arranged at a predetermined interval. Insulating layer 20 on which the first electrode 21 is formed
The surfaces of the parallel electrodes 21a and 21b of the first electrode 21 are
A groove 24 is formed along the space between them.

At the intersection of the first electrode 21 and the second electrode 22, the bottom wall of the groove 24 of the insulating layer 20 and the second electrode 22,
A toner insertion hole 23 that communicates with the groove 24 of the insulating layer from the surface of the second electrode 22 is formed.

By the electric field between the toner supply roller 1 (see FIG. 5) and the first electrode 21, the toner is supplied from the toner supply roller 1 side onto the first electrode 21. And FIG.
As shown in FIG. 2, the toner accumulated on the first electrode 21 is prevented from being accumulated between the parallel electrode portions 21 a and 21 b of the first electrode 21 by the electric field between the first electrode 21 and the second electrode 22 and the insulating layer 2
After passing through the 0 groove 24 and the toner insertion hole 23, it is transferred to the recording paper.

In the above print head, as shown in FIG.
In the vicinity of a position directly below the toner insertion hole 23, the first electrode 21
Not only the toner accumulated on the first electrode 21
The toner accumulated on the first electrode 21 can also be supplied to the toner insertion hole 23 in the vicinity of an intermediate position between the toner insertion holes 23 adjacent to each other in the length direction, so that a high image density can be obtained. . As a result, high speed printing is possible.

[0023]

According to the present invention, it is possible to obtain a print head in a powder jet image forming apparatus which can obtain high image density and can perform high-speed printing.

[Brief description of the drawings]

FIG. 1 is a partially enlarged plan view showing a print head according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line bb of FIG.

3 is a cross-sectional view taken along the line cc of FIG.

FIG. 4 is a cross-sectional view showing a state in which the toner accumulated on the first electrode is supplied to the toner insertion hole.

FIG. 5 is a configuration diagram showing a basic configuration of a powder jet image forming apparatus.

FIG. 6 is a plan view showing the basic structure of the print head.

7 is a cross-sectional view taken along the line aa of FIG.

FIG. 8 is a time chart showing changes in applied voltage to each first electrode.

FIG. 9 is a cross-sectional view showing a state in which the toner accumulated on the first electrode is supplied to the toner insertion hole.

[Explanation of symbols]

 20 Insulating Layer 21 First Electrode 22 Second Electrode 23 Toner Insertion Hole 24 Groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuki Ito 1-22-28 Tamazo, Chuo-ku, Osaka City, Osaka Prefecture Mita Kogyo Co., Ltd. (72) Hiroyuki Yamaji 1-2-chome Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture No. 28 Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A matrix composed of a plurality of first electrodes having a developer supply portion of an insulating layer formed on a wrinkle surface and a plurality of second electrodes having a recording paper conveying portion of an insulating layer formed on a wrinkle surface. In a print head in a powder jet image forming apparatus in which a striped electrode portion is formed, a main portion of each first electrode is composed of parallel electrode portions arranged at predetermined intervals, and the first electrode is formed. A groove is formed on the surface of the insulating layer along the portion between the parallel electrode portions of the first electrode, and the bottom wall of the groove of the insulating layer is formed at the intersection of the first electrode and the second electrode. A print head in a powder jet image forming apparatus, wherein a developer insertion hole communicating with the groove of the insulating layer from the surface of the second electrode is formed in the second electrode.