JPH0761027A - Powder jet image forming apparatus - Google Patents

Abstract

PURPOSE:To provide a powder jet image forming apparatus wherein an amount of toner to be fed from a toner feed roller to a printing head can be made constant. CONSTITUTION:Each first insulating layer 201 having a first electrode 211 formed on the surface of the layer 201, each second insulating layer 202 having a second electrode 212 formed on the surface of the layer 202 and a shield plate 203 held between the first insulating layer 201 and the second insulating layer 202 are arranged between the first electrode 211 and the second electrode 212. The first electrodes 211, the first insulating layers 201, the shield plates 203, the second insulating layers 202 and the second electrodes 212 have a developing powder passage hole 213 opened at each of intersections of the first electrodes 211 and the second electrodes 212.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As an image forming apparatus, the applicant of the present invention has shown in FIG.
The powder jet image forming apparatus as shown in FIG. This powder jet image forming apparatus includes a print head 2 for controlling passage of toner charged to a predetermined polarity, for example, a negative polarity, a toner supply roller 1 for supplying toner to the print head 2, and a recording paper P. A recording paper feed roller 3 for guiding the print head 2 side, and a fixing roller 4 for fixing the toner transferred onto the recording paper P to the recording paper P.
It has and.

As shown in FIGS. 7 and 8, the print head 2 includes an insulating substrate 20, a plurality of first electrodes 21 formed on the surface of the insulating substrate 20 on the toner supply roller 1 side, and the insulating substrate 20. It is provided with a plurality of second electrodes 22 formed on the surface of the recording paper conveyance roller 3 side. A plurality of first electrodes 21
And the plurality of second electrodes 22 form a matrix electrode. A toner passage hole 23 penetrating the print head 2 is formed at each intersection of the first electrode 21 and the second electrode 22.

An on-voltage (for example -100V) and an off-voltage (for example + 100V) are selectively applied to each first electrode 21. Each second electrode 22 has an on-voltage (for example, +50 V) and an off-voltage (for example, −20 V).
0V) is selectively applied. The respective first electrodes 21 are subjected to dimic scan control, and the applied voltage is sequentially turned on at a predetermined unit time interval. Then, only when the applied voltage to both the first electrode 21 and the second electrode 22 is the on-voltage,
The toner passes through the toner insertion hole 23 at the intersection of these points, and dot printing is performed.

The recording paper P is moved in the direction perpendicular to the first electrode 21 by the recording paper conveying roller 3 and in the direction in which control by dynamic scanning of the first electrode 21 proceeds (arrow A in FIG. 8).
Is conveyed in the direction indicated by. The recording paper transport roller 3 has
A voltage of + 500V is applied. The toner supply roller 1 is grounded and its surface potential is 0V.

The print head 2 is provided with an ultrasonic vibrator 5 for applying ultrasonic vibration to the print head 2 to prevent the toner insertion hole 23 from being clogged with toner.

[0007]

In such a powder jet image forming apparatus, when the applied voltage to the first electrode 21 is the off voltage (+ 100V), the toner supply roller 1 having the first electrode 21 and the surface potential of 0V. The toner is supplied from the toner supply roller 1 to the first electrode 21 by an electric field (hereinafter referred to as a toner supply electric field) generated between and.

By the way, the voltage applied to each second electrode 22 is
The voltage is turned on (+ 50V) or off (-200V) according to the print dot data. Therefore, the toner supply electric field is affected by the voltage applied to the second electrode 22. Therefore, there is a problem in that the amount of toner supplied from the toner supply roller 1 to the print head 2 varies depending on the image to be formed, resulting in uneven printing.

An object of the present invention is to provide a powder jet image forming apparatus capable of keeping the amount of toner supplied from a toner supply roller to a print head constant.

[0010]

In a powder jet image forming apparatus according to the present invention, a plurality of first electrodes and a plurality of second electrodes are arranged in a matrix with an insulating layer interposed therebetween, and the first electrode A print head having a developer insertion hole formed at each intersection of the first electrode and the second electrode; and a developer supply roller for supplying the developer charged with a predetermined polarity to the print head. The developer is supplied from the developer supply roller side to the print head side by controlling the electric field between the developer supply roller and the development by controlling the electric field between the first electrode and the second electrode. In a powder jet image forming apparatus in which an agent insertion hole is opened and closed in a potential manner, a first insulating layer having a first electrode formed on a surface and a second electrode provided on a surface are provided between a first electrode and a second electrode. The second insulating layer, the first insulating layer and the A shield plate interposed between the first electrode, the first insulating layer, the shield plate, the second insulating layer, and the second electrode is disposed between the first electrode and the second electrode. Has a developer insertion hole formed therein, and the diameters of the developer insertion holes formed in the first electrode, the first insulating layer, the second insulating layer, and the second electrode are equal, and the developer insertion hole formed in the shield plate is The diameter of the hole is larger than the diameter of the developer insertion hole formed in the first electrode and smaller than the width of the first electrode.

[0011]

By controlling the electric field between the first electrode and the developer supply roller, the developer is supplied from the developer supply roller side to the print head side. Further, the developer insertion hole is opened and closed in potential by controlling the electric field between the first electrode and the second electrode.

Since the shield plate is arranged between the first electrode and the second electrode, the first electrode and the second electrode are exposed to the electric field generated between the first electrode and the developer supply roller. The influence of the electric field between them disappears. As a result, the amount of developer supplied from the developer supply roller to the print head is kept constant.

The diameters of the developer insertion holes formed in the first electrode, the first insulating layer, the second insulation layer and the second electrode are equal, and the diameters of the developer insertion holes formed in the shield plate are the same as those of the first electrode. It is larger than the diameter of the opened developer insertion hole and smaller than the width of the first electrode. For this reason, the electric field generated between the first electrode and the second electrode is not disturbed by the shield plate near the developer insertion hole. That is, even if the shield plate is provided between the first electrode and the second electrode, the control for opening / closing the developer insertion hole in a potential manner is normally performed.

[0014]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic structure of a powder jet image forming apparatus.

The powder jet image forming apparatus includes a print head 200 for controlling passage of toner, a toner supply roller 1 for supplying the toner charged to a predetermined polarity to the print head 200, and a recording paper P for the print head. A recording paper conveyance roller 3 for guiding the recording paper P to the 200 side and a fixing roller 4 for fixing the toner transferred to the recording paper P to the recording paper P are provided.

The toner conveyed by the toner supply roller 1 is assumed to be negatively charged here.
The toner supply roller 1 is grounded and its surface potential is 0V.

As shown in FIGS. 1 to 4, the print head 200 includes two insulating substrates 201 and 202 and both insulating substrates 2.
01 and 202, a plurality of first electrodes 211 formed on the surface of the toner supply roller 1 side of the toner supply roller 1 side of the insulating substrate 201 on the toner supply roller 1 side, and an insulating substrate of the recording conveyance roller 3 side. A plurality of second electrodes 212 (control electrodes) formed on the surface of the recording / conveying roller 3 of 202 are provided. In this example, eight parallel first electrodes 211 are arranged at equal intervals.
In addition, 400 second electrodes 212 extending in a direction parallel to each other and slightly inclined with respect to a direction orthogonal to the first electrode 211 are arranged at equal intervals. That is, 8
The first electrodes 211 of the book and the second electrodes 212 of the book of 400 form a matrix electrode of 8 rows and 400 columns.

Then, each first electrode 211 and each second electrode 2
A toner passage hole 213 penetrating the print head 200 is formed at each intersection with the print head 200. That is, the print head 200 has 3200 toner passage holes 213 formed therein. Each toner insertion hole 213 is provided with the first electrode 21.
1 has a hole 213a formed therein, a hole 213b formed in the insulating substrate 201, and a hole 213 formed in the shield plate 203.
c, a hole 213d formed in the insulating substrate 202, and a hole 213e formed in the second electrode 212. These holes 2
The centers of 13a to 213e are on the same axis.

A hole 213 formed in the first electrode 211, the insulating substrate 201, the insulating substrate 202 and the second electrode 212.
The diameters of a, 213b, 213d, and 213e are the same. The diameter of the hole 213c formed in the shield plate 203 is larger than the diameter of the hole 213a formed in the first electrode 211 and smaller than the width of the first electrode 211.

Specific examples of the size of each part of the print head 200 are shown below. The thickness of each insulating substrate 201, 202 is 10
It is 0 μm. The thickness of the first electrode 211, the second electrode 212, and the shield plate 203 is 35 μm. First electrode 2
The width of 11 is 300 μm. The diameter of the holes 213a, 213b, 213d, and 213e formed in the first electrode 211, the insulating substrate 201, the insulating substrate 202, and the second electrode 212 is 150 μm. The diameter of the hole 213c formed in the shield plate 203 is 250 μm.

Each first electrode 211 has an on-voltage (for example -100V) and an off-voltage (for example + 100V).
And are selectively applied. Each second electrode 212 has an on-voltage (for example +50 V) and an off-voltage (for example −50 V).
200V) is selectively applied. Shield plate 203
Is grounded.

FIG. 5 shows the applied voltage V of each first electrode 211.
The change of 1-0-V1-7 is shown. As shown in FIG. 5, each first electrode 211 is controlled by a dynamic scan.
The applied voltage is sequentially turned on at a predetermined unit time interval.
Then, only when the applied voltage to both the first electrode 211 and the second electrode 212 is the on-voltage, both electrodes 211 and 212 are
Due to the electric field generated therebetween, toner passes through the toner insertion hole 213 at the intersection of the electrodes 211 and 212, and dot printing is performed.

The recording sheet P is conveyed by the recording sheet conveying roller 3 in a direction perpendicular to the first electrode 211 and in a direction in which control by dynamic scanning of the first electrode 211 proceeds (direction indicated by arrow A in FIG. 2). . The base roller 3 has
A voltage of + 500V is applied.

The print head 200 includes the print head 200.
An ultrasonic vibrator 5 is attached to prevent the toner from being clogged in the toner insertion hole 213 by applying ultrasonic vibration.

FIG. 6 shows the electrical construction of the powder jet image forming apparatus.

An electric clutch 11 for controlling the drive of the toner supply roller 1, an electric clutch 12 for controlling the drive of the recording paper conveying roller 3, a switching circuit 13 for the applied voltage of each first electrode 21, and an application of each second electrode 22. The voltage switching circuit 14 and the drive circuit 15 for the ultrasonic transducer 5 are controlled by the CPU 10. The CPU 10 includes a ROM 16 that stores the program and other data and a RAM 17 that stores necessary data. Print dot data, an input signal from the operation unit 18, and the like are input to the CPU 10.

During the printing process, the ultrasonic transducer 5 is driven. Further, the toner supply roller 1 is driven and the first electrode 211 is subjected to dynamic scan control. The potential of the first electrode 211 is an off voltage (+ 100V)
The first electrode 211 and the toner supply roller 1
Toner is supplied from the toner supply roller 1 side to the print head 200 side by an electric field (hereinafter referred to as a toner supply electric field) generated between the toner supply roller 1 side and the (potential 0 V).

Further, each second electrode 212 is switched to the ON voltage or the OFF voltage based on the print dot data. The potential of each second electrode 212 is an on-voltage (+50 V) when printing is performed and an off-voltage (−50 V) when printing is not performed.
200V). When the potential of the first electrode 211 is the on-voltage (-100V) and the potential of the second electrode 212 is the on-voltage (+ 50V), the toner passes through the toner insertion hole 23 at the intersection of the two, and the recording paper P Is printed with dots.

In this embodiment, the shield plate 203
However, since it is provided between the first electrode 111 and the second electrode 112, the voltage applied to the second electrode 212 is less likely to affect the toner supply electric field. Therefore, the toner supply amount can be kept constant.

Even if the shield plate 203 is provided between the first electrode 211 and the second electrode 212 as described above, the diameter of the hole 213c formed in the shield plate 203 is equal to that of the first electrode 2.
11 is larger than the diameter of the hole 213a formed in the opening 11 and smaller than the width of the first electrode 211, the voltage applied to the first electrode 211 and the second electrode 212 near the toner insertion hole 213.
Since the electric field formed by the applied voltage is not disturbed, the control for opening / closing the toner insertion hole 213 in a potential manner is normally performed.

[0032]

According to the present invention, the amount of toner supplied from the toner supply roller to the print head can be made constant.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a powder jet image forming apparatus.

FIG. 2 is a plan view showing the arrangement of first electrodes and second electrodes in the print head.

FIG. 3 is a partially enlarged view of FIG.

4 is an enlarged cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a time chart showing changes in applied voltage to each first electrode.

FIG. 6 is an electrical block diagram showing an electrical configuration of the powder jet image forming apparatus.

FIG. 7 is a configuration diagram showing a schematic configuration of a conventional powder jet image forming apparatus.

FIG. 8 is a plan view showing the arrangement of first electrodes and second electrodes in the print head.

[Explanation of symbols]

 1 Toner Supply Roller 3 Recording Paper Conveying Roller 200 Print Head 201 Insulating Substrate 202 Insulating Substrate 203 Shield Plate 211 First Electrode 212 Second Electrode 213 Toner Insertion Hole 213a Toner Insertion Hole 213c Opened in the First Electrode Toner insertion hole

Claims (1)

[Claims] 1. A plurality of first electrodes and a plurality of second electrodes are arranged in a matrix with an insulating layer interposed therebetween, and a developer insertion hole is formed at each intersection of the first electrode and the second electrode. And a developer supply roller for supplying the developer charged to a predetermined polarity to the print head.
The developer is supplied from the developer supply roller side to the print head side by controlling the electric field between the electrode and the developer supply roller, and the electric field between the first electrode and the second electrode is controlled. In a powder jet image forming apparatus in which a developer insertion hole is opened / closed in a potential manner by means of, a first insulating layer having a first electrode formed on a surface, and a second electrode between a first electrode and a second electrode. The second on the surface
An insulating layer and a shield plate interposed between the first insulating layer and the second insulating layer are arranged, and the first electrode, the first insulating layer, the shield plate, the second insulating layer, and the second electrode are provided. , A developer insertion hole is formed at each intersection of the first electrode and the second electrode, and the diameter of the developer insertion hole formed in the first electrode, the first insulating layer, the second insulating layer and the second electrode is Equally, the diameter of the developer insertion hole formed in the shield plate is larger than the diameter of the developer insertion hole formed in the first electrode and smaller than the width of the first electrode.