JPH03139669A - Electrostatic recorder - Google Patents

Abstract

PURPOSE:To prevent a transfer electrode from being stained by making the potential of a bias voltage applied to the transfer electrode equivalent to that of a bias voltage applied to a developer carrier when a recording medium is not present between the developer carrier and the transfer electrode. CONSTITUTION:An ion flow moving from an ion supplying source 6 to a developer thin layer is modulated according to an image signal by applying a voltage, which corresponds to the image signal, to an ion flow modulating means 9 by means of a control power source 10; consequently the ion flow reaches the developer thin layer. For a formed electrostatic latent image, developer is transferred on the recording medium by applying a bias voltage by means of a bias power source 7, when a recording medium is present between the developer carrier 1 and the transfer electrode 11. The potential of the developer carrier and that of the transfer electrode are made equivalent to each other by the use of a switch 12, when a recording medium is not present between the developer carrier 1 and the transfer electrode 11. By controlling the applying of a bias voltage in such a manner, developer is not splashed from the developer carrier 1 to the transfer electrode 11, and therefore the electrode 11 can be prevented from being stained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic recording device that forms an electrostatic latent image on a thin layer of developer on a developer carrier using an ion supply source and ion flow modulating means.

BACKGROUND OF THE INVENTION Conventionally, various types of electrostatic recording techniques have been known.
Examples include those described in Japanese Patent No.-209481. 7th
The figure shows an example of this. In this electrostatic recording device, the developer 5 in the hopper 21 is transported by the developer transport roll 14.
The toner is supplied onto a developer carrier 1 having a dielectric layer 2 on a conductive cylinder 3, and is formed into a thin layer of uniform thickness by a layer forming member 4 in contact with the developer carrier 1. , the layer forming member 4 and the developer 5 are tribo-electrified to a positive or negative value by a tribo-electrification series. As a result, the developer carrier 1 carries a thin layer of negatively charged toner. An ion flow is supplied to this thin layer from an ion supply source 6, and the ion flow is modulated by an ion flow modulation means 9 consisting of a plurality of aperture elements, and a voltage according to the image signal is controlled by the ion flow modulation means 1o. 9 modulates the ion flow from the ion source in accordance with the image signal, and causes this modulated ion flow to selectively impinge on the charged toner thin layer to generate toner in accordance with the image signal. Forms an electrostatic latent image. The formed toner electrostatic latent image is transferred onto the recording medium 13 by applying a bias voltage between the developer carrier 1 and the transfer electrode 11 from the bias power supply 8, thereby forming a toner image.

In this electrostatic recording device, the value of the bias voltage applied to the transfer electrode is constant, and the value is set so that the developer to be transferred from the developer carrier to the recording medium is transferred to the recording medium. has been done.

Problem to be Solved by the Invention However, when a conventional electrostatic recording device as shown in FIG. 7 is applied to a printer or the like, if a recording medium exists between the developer carrier and the transfer electrode, , the same problem does not occur, but if there is no recording medium between the developer carrier and the transfer electrode, there is a problem that the developer transfers from the developer carrier to the transfer electrode and contaminates the transfer electrode. .

The present invention has been made to solve the above-mentioned drawbacks of conventional electrostatic recording media, and its purpose is to prevent contamination of the transfer electrode when there is no recording medium between the transfer electrode and the transfer electrode. An object of the present invention is to provide an electrostatic recording device.

Means and Effects for Solving the Problems The present invention provides a developer carrier that carries a thin layer of charged developer on its surface, and a developer carrier that supports a thin layer of developer on the developer carrier in accordance with an image signal. In an electrostatic recording device comprising a modulated ion supply means for supplying a modulated ion flow and a transfer means for selectively transferring the developer on the developer carrier to a recording medium, the transfer means It has a transfer electrode facing the developer carrier, and a voltage application means for applying a bias voltage to the transfer electrode, and the voltage application means is configured to apply a bias voltage to the transfer electrode when the recording medium is present between the developer carrier and the transfer electrode. applies a bias voltage set so that the developer is transferred from the developer carrier to the recording medium, and when the recording medium is not present between the developer carrier and the transfer electrode, the developer is transferred to the transfer electrode. The present invention is characterized by comprising means for controlling voltage application so as to apply a bias voltage having the same potential as that of the agent carrier.

The basic configuration of the present invention will be explained with reference to FIG. 1st
The figure shows the general structure of the electrostatic recording device of the present invention.
(a) shows a state in which a recording medium exists between the developer carrier and the transfer electrode, and (b) shows a state in which the recording medium does not exist between the developer carrier and the transfer electrode.

The one-component developer 5 supplied onto the developer carrier 1 forms a thin layer of uniform thickness with the layer forming member 4 in contact with the developer carrier 1, and also forms a thin layer with a uniform thickness on the layer forming member 4. Due to frictional electrification, it is charged either positively or negatively. The ion supply source 6 supplies an ion flow to this developer thin layer under the application of a bias voltage by the bias source 8.
At that time, by applying a voltage corresponding to the image signal from the control power supply 1o to the ion flow modulation means 9, the ion supply source 6
The ion flow toward the developer thin layer is modulated according to the image signal and reaches the developer thin layer. At this time, an electrostatic latent image is formed on the thin developer layer. When the recording medium 13 is present between the developer carrier 1 and the transfer electrode 11, the electrostatic latent image formed is transferred to the recording medium by applying a bias voltage from the bias power supply 7. transcribed. When there is no recording medium between the developer carrier 1 and the transfer electrode 11, switch 2 is used to make the developer carrier and the transfer electrode have the same potential as shown in FIG. 1(b). Make it. By controlling the application of the bias voltage in this way, when no recording medium is present, the developer is prevented from flying from the developer carrier to the transfer electrode due to electrical force, and the transfer electrode is prevented from being contaminated. Can be done.

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

FIG. 2 shows an embodiment of the electrostatic recording device of the present invention. In the figure, 1 is a developer carrier, and a dielectric layer 2 is provided on a conductive cylinder 3. Reference numeral 4 denotes a layer forming member, which regulates the developer 5 conveyed by the developer conveyance roll 14 to form a charged thin layer with a thickness similar to - on the developer carrier. 6 is an ion supply source, and 9 is an ion flow modulating means.

A transfer electrode 11 is connected to bias power supplies 7 and 8 by a switch I2. A recording medium 13 is guided and conveyed by paper guides 19 and 20.

In the electrostatic recording device described above, the developer carrier 1 has a structure in which a dielectric cylinder made of thermosetting phenolic resin is fitted and bonded to a conductive shaft made of stainless steel, and the transfer electrode is made of brass. It is composed of. The developer 5 accommodated in the hopper 21 is transported to the developer carrier roll 1 by a developer transport roll 14 having a rubber layer on its surface.
The developer is supplied onto the developer carrier 1 . The developer on the developer carrier roll 1 is regulated by the layer forming member 4 to form a thin layer of developer with a uniform thickness, and frictional electrification between the layer forming member 4 and the developer 5 is applied. It is uniformly charged depending on the series.

In this example, the charging potential of the thin developer layer is -30
~-70V. Further, as the layer forming member 4, a stainless steel member is used as a support, and a friction portion with the developer 5 is made of silicone rubber.

As the ion flow modulating means 9, for example, Japanese Patent Application Laid-Open No. 61-25
The ring-shaped electrode shown in Publication No. 166 or Japanese Patent Application Laid-open No. 1981
The slit-shaped electrode shown in Japanese Patent No. 169853 is used, and the slit-like electrode shown in Japanese Patent No. 169853 is used, and the electrode is 0.02 to 5 mm5 preferably 0.1 mm from the developer carrier roll 1 with a holding means such as a tracking roll.
- Provided at intervals of 3 orders.

The ion source 6 is connected to the ceramic plate 2 as shown in FIG.
The device is a plate-shaped element in which a flat plate electrode 23 is embedded, and a discharge electrode 22 is provided on one surface. The buried flat plate electrode 23 and discharge electrode 22 are formed by applying thick film printing, and are made of nickel, tungsten, or the like from the viewpoint of ozone resistance.

A ceramic with a thickness of 0.5 mm is interposed between the flat plate electrode 23 and the discharge electrode 22. Between the flat plate electrode 23 and the discharge electrode 22, a frequency of 500 to 1.0 Kllz,
An AC voltage having a peak-to-peak voltage v pp of 3.5 to 8 KV is applied to generate ions by creeping discharge.

As shown in FIG. 4, the ion modulation means 9 and the ion supply source 6 are integrated by an insulating support 25 made of resin.
A chamber 28 is formed. In the chamber 28,
Pressurized air 27 is supplied from the pipe 26, and the static pressure is between 1 and 1.
000mm H20s preferably 10-500mm
H2O range. The material constituting the insulating support 25 may be any insulating material, and in addition to resin, ceramic, glass, rubber, etc. can be used.

In addition to the above, as the ion supply source 6,
For example, a corona discharge device having a structure as shown in FIG. 5, which is composed of a discharge wire 29, a shield 30 surrounding the discharge wire, and a high-voltage power source 31, may be used.

By applying a voltage corresponding to the image signal from the control power supply 10 to the ion flow modulating means 9, the ion flow from the ion supply source 6 is modulated according to the image signal. This modulated ion flow selectively impinges on the charged developer thin layer to form an electrostatic latent image on the developer thin layer in response to an image signal.

Next, the thin developer layer having the electrostatic latent image formed as described above is carried by the developer carrier 1 and reaches the transfer position, where it is brought to face the recording medium without contacting it. The recording medium is conveyed onto the paper guide 19 by the recording medium conveyance roll 17, but at this time, the intrusion of the recording medium 13 is detected by
This is performed by the recording medium detection sensor 18. A photoelectric sensor, a mechanical switch, or the like is used as the recording medium detection sensor, and it is detected whether the recording medium has entered the recording medium.

Since the distance from the recording medium detection sensor 18 to the transfer electrode 11 is constant, the leading edge of the recording medium transported at a constant speed is detected by the recording medium detection sensor → No. 18 and then reaches the transfer electrode a certain period of time later. reach. Therefore, if an appropriate value is set in the timer in advance and the timer is activated at the same time as the recording medium detection sensor 18 detects the leading edge of the recording medium, the timer is set as soon as the leading edge of the recording medium reaches the transfer electrode. The switch 12 is switched according to the value. While the recording medium passes between the developer carrier 1 and the transfer electrode, it is in the state shown in FIG. 1(a), and a bias voltage for transfer is applied to the transfer electrode 11 from the bias power supply 7. be done.

The end of the recording medium is similarly detected by the recording medium detection sensor 18, which activates the timer, and at the same time as the end of the recording medium passes the transfer electrode, the switch 12 is switched, as shown in FIG. 1(a). The state changes to the state shown in FIG. 1(b). When the recording medium is not present between the developer carrier 1 and the transfer electrode, the transfer electrode is connected to the bias power supply 8, so that it has the same potential as the developer carrier 1. Therefore, the developer on the developer carrier 1 is not transferred to the transfer electrode 11. In the above case, the switch I2 is specifically configured with a relay control circuit or the like.

Next, the recording medium passes from the paper guide 20 between the heat roll 15 and the pressure roll 16, and the transferred image is fixed thereon.

FIG. 6' shows another embodiment of the present invention, in which bias power supplies for applying bias voltages to the developer carrier 1 and the transfer electrode 11 are installed independently. ing. In the figure, 32 is a bias power supply for applying a bias to the developer carrier 1, and 33 is a bias power supply for applying a bias voltage to the transfer electrode 11 so that it has the same potential as the developer carrier 1. Yes, 3 again
A bias power source 4 applies a bias voltage to the transfer electrode 11 so that an electric field for transfer is generated between the developer carrier 1 and the transfer electrode 1. and transfer electrode II
The bias voltage applied to the bias voltage can be switched between bias power supplies 33 and 34 by a switch I2.

Effects of the Invention Since the electrostatic recording device of the present invention has the above configuration, when there is no recording medium between the developer carrier and the transfer electrode, the bias pressure applied to the transfer electrode is reduced. The potential is the same as the bias voltage applied to the developer carrier, and the developer does not transfer from the developer carrier to the transfer electrode. Therefore, in the electrostatic recording apparatus of the present invention, the transfer electrode is not contaminated, so that a good transferred image can always be formed.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an electrostatic recording device of the present invention, FIG. 2 is a schematic configuration diagram of an embodiment of the electrostatic recording device of the present invention, and FIG.
The figure is a sectional view of an example of an ion source, FIG. 4 is a block diagram of an ion flow modulating means, FIG. 5 is a sectional view of another example of an ion source, and FIG. 6 is a sectional view of an electrostatic recording device of the present invention. A schematic configuration diagram of another embodiment, FIG. 7 is a configuration diagram of a conventional electrostatic recording device. I...Developer carrier, 2...Electroconductive cylinder, 31.・
Dielectric layer, 4... Layer forming member, 5... Toner, 6...
...Ion supply source, 7, 8...Bias power supply, 9...
- Ion flow modulation means, 10... control power supply, 11...
Transfer electrode, I2... switch, 13... recording medium,
14... Developer transport roll, 15...-2 Heat roll, 16... Pressure roll, 17...
...Recording medium transport roll, 18...Recording medium detection sensor, 19°20...Paper guide, 21...Hopper, 22...Discharge electrode, 23...Flat electrode, 24...
...Ceramic plate, 25...Insulating support, 26...
・Pipe, 27... Pressurized air, 28... Channel, 2
9...Discharge wire, 30...Shield, 31...
・High voltage power supply, 32, 33. 34...bias power supply.

Claims (1)

[Claims] (1) A developer carrier that carries a thin layer of charged developer on its surface, and modulated ions that supply an ion flow modulated in accordance with an image signal to the developer thin layer on the developer carrier. In an electrostatic recording device comprising a supply means and a transfer means for selectively transferring the developer on the developer carrier to a recording medium, the transfer means includes a transfer electrode facing the developer carrier; The voltage applying means applies a bias voltage to the transfer electrode, and when the recording medium is present between the developer carrying member and the transfer electrode, the voltage applying means applies the developer from above the developer carrying member. A bias voltage set to transfer the image to the recording medium is applied, and when the recording medium is not present between the developer carrier and the transfer electrode, a bias voltage of the same potential as the developer carrier is applied to the transfer electrode. An electrostatic recording device characterized by comprising means for controlling the application of a voltage.