JPS61282862A - Corona discharging electrode of electrostatic recording device - Google Patents

Abstract

PURPOSE:To form a copy image having good quality and to use the electrostatic charging electrode and transfer electrode of an electrostatic recording device in common by constituting a wire electrode for discharging at variable distance from an image carrier. CONSTITUTION:The discharging wire electrode 22 of a corona discharging electrode 2 is arranged while isolated from a beltlike photosensitive body 1 in electrostatic charging operation and the beltlike photosensitive body 1 is charged electrostatically and successively. The charged beltlike photosensitive body 1 is processed by exposure and development under copy process control to form an original image. Then, the corona discharging electrode 2 serves as the transfer electrode to transfer the original image to recordin paper P. In this case, the corona discharging electrode 2 has its discharging wire electrode 22 arranged nearby the beltlike photosensitive body 1. This discharging wire electrode 22 is shifted in position through the operation of an eccentric cam 23.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a band which is arranged opposite to an image carrier. The present invention relates to an electrostatic recording device such as an electrophotographic copying machine that has a corona discharge electrode that serves as both an electrode and a transfer electrode.

2. Description of the Related Art In the electrostatic recording device, for example, an electrophotographic copying machine (hereinafter referred to as a copying machine), it is generally known that a corotron or scorotron is used as the corona discharge electrode. There is a problem in that although one of the performances required for a charging electrode and a transfer electrode can be satisfied, the other cannot be satisfied, and there is a need for a corona discharge electrode that can satisfy both of the above-mentioned performances.

In other words, the corona discharge electrode employing a corotron is connected to a high-voltage DC power supply circuit that can switch between high and low current values of 2fti, and when it acts as a charging electrode, it is connected to the lower power supply circuit and acts as a transfer electrode. By connecting it to a higher power supply circuit, it can serve as both a charging electrode and a transfer electrode. As a transfer electrode, it is capable of transferring with good transfer efficiency, but as a charging electrode, it is likely to cause discharge unevenness and it is difficult to ensure a highly stable charging potential. On the other hand, a corona discharge electrode employing a scorotron is configured so that it can serve both as a charging electrode and a transfer electrode by adjusting the voltage applied to the grid electrode and controlling the discharge current. As a charging electrode, it is possible to secure a highly stable charging potential, but as a transfer electrode, a sufficient discharge current cannot be obtained and it is difficult to perform a transfer operation with good transfer efficiency. Furthermore, when the grid electrode acts as a transfer electrode, the recording paper comes into contact with the grid electrode, causing damage to the grid electrode.

As mentioned above, the corona discharge electrode in a conventional copying machine is
There is a problem in that the performance required for both a charging electrode and a transfer electrode cannot be satisfied.

OBJECTS OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and to satisfy both the performance required for a charging electrode and a transfer electrode, and to be able to obtain high-quality copy images.
An object of the present invention is to provide a corona discharge electrode that serves both as a charging electrode and a transfer electrode of an electrostatic recording device.

Structure of the Invention The present invention has been completed to achieve the above-mentioned object, and its structure is directed to an electrostatic recording device having a corona discharge electrode disposed opposite to an image carrier and serving as both a charging electrode and a transfer electrode. The present invention relates to a corona discharge electrode for an electrostatic recording device, characterized in that the discharge wire electrode is configured such that the distance from the image carrier can be changed. By changing the distance of the discharge wire electrode from the image carrier,
The magnitude and concentration of the discharge current of the corona discharge electrode can be easily adjusted, and when the wire electrode is placed close to the image carrier, the discharge current is generated in a large and concentrated manner, 1. When placed at a distance. The discharge current is generated in a small and uniformly distributed manner. I want to fly,
The corona discharge electrode of the present invention can generate a discharge current suitable for the charging electrode and the transfer electrode by changing the distance between the discharge wire and the electrode with respect to the image carrier.
It can satisfy both the properties and performance required for a charging electrode and a transfer electrode. In particular, it is preferable that when acting as a charging electrode, the wire electrode is arranged at a distance from the image carrier, and when acting as a transfer electrode, it is arranged close to it.

Setting the point at which the wire electrode acts as a charging electrode or a transfer electrode, that is, changing the distance of the wire electrode to the image carrier, is as follows:
Preferably, this is performed in conjunction with the movement of the recording paper. In particular, the time point at which it acts as a charging electrode is set at the point after the recording paper passes over the corona discharge electrode, and the time point at which it acts as a transfer electrode is set at the point after the recording paper passes over the corona discharge electrode. and 5. Preferably, the configuration is configured such that the settings are set in conjunction with each other.

In addition, in order to change the distance of the discharge wire electrode with respect to the image carrier, the wire electrode itself may be provided movably, or the entire corona discharge electrode may be provided movably. Further, it is preferable that the distance of the discharge wire electrode is set so that it can be continuously changed, so that the discharge current can be finely adjusted, and the optimum conditions for charging and transfer can be easily adjusted. can be done.

Example The present invention will be explained in detail by way of examples.

This embodiment describes a copying machine having a corona discharge electrode that serves both as a charging electrode and a transfer electrode. This corona discharge electrode is movable within a pole case and is characterized by having a cut discharge wire electrode, which will be described with reference to FIGS. 1 and 2.

FIG. 1 is a schematic explanatory diagram of the main parts of the copying machine to explain the state when the corona radiation t& of this embodiment acts as a charging electrode, and FIG. 2 similarly shows the state when it acts as a transfer electrode. FIG. In the figure, reference numeral 1 denotes a belt-shaped photoreceptor as an image carrier, which is supported by a plurality of support rollers 11 so as to rotate in the direction of the arrow. 2 is a corona discharge electrode, which is a discharge wire electrode 2 housed in an electrode case 21.
It has 2. Both ends of the wire electrode 22 are supported by a pair of eccentric cams 23 rotatably provided at both ends of the electrode case 210, and are connected to a high voltage DC power supply circuit (not shown). Reference numeral 3 denotes a paper feed roller that is part of a paper feed device that feeds the recording paper P. 4 is a sensor that detects the rear end of the recording paper P and sends a signal to operate the eccentric cam 23 so as to set the wire electrode 22 from the state shown in FIG. 2 to the state shown in FIG. . Note that the belt-shaped photoreceptor 1. The operations of the high-voltage DC power supply circuit, paper feeding device, etc. are controlled by the copy process control.
The eccentric cam 23 is configured to be operated so as to set the state shown in the figure to the state shown in FIG. 2.

The copying machine shown in the figure is constructed as described above, and its operations during charging and transfer are as follows. When charging the belt, the discharge wire electrode 22 of the corona discharge electrode 2 is placed at a position separated from the belt-shaped photoreceptor 1 as shown in FIG. 1, and sequentially charges the belt-shaped photoreceptor 1. The charged belt-shaped photoreceptor IK is exposed and provided at a position (not shown) under copy process control to form an original image.

Eventually, the original image is moved onto the corona discharge electrode 2.

On the other hand, the recording paper P is moved by the paper feed roller 3 so that its leading edge coincides with the leading edge of the original image and the corona discharge electrode 2.
The paper is fed by As mentioned above, the original image and recording paper P
When the tip reaches above the corona discharge electrode 2, the corona discharge electrode 2
acts as a transfer electrode, and the original image is transferred onto the recording paper P. At this time, the corona discharge electrode 2 has a discharge wire electrode 22 disposed close to the belt-like light body IK, as shown in FIG. 2, and functions as a transfer electrode.

That is, when the feeding of the recording paper P is started by the paper feeding roller 3, the eccentric cam 23 of the corona discharge &2 is operated and the discharge wire electrode 22 approaches the belt-shaped photoreceptor 1 as shown in FIG. will be placed.

Since the paper feed roller 3 and the corona discharge electrode 2 are provided at a predetermined distance apart, the point in time when the leading edge of the original image formed on the belt-shaped photoreceptor 1 and the leading edge of the recording paper P reach the corona discharge electrode 2. The discharge wire electrode 22 has already been arranged in the state shown in FIG. 2, and the corona discharge electrode 2 has reached the part of the support roller 11 where the curvature of the transfer electric body 1 changes in the state shown in FIG. At this time, the sheet is separated from the belt-shaped photoreceptor 1 and fed to a fixing device (not shown) to form a copy image. At this time, the corona discharge electrode 2 acts as a charging electrode after the recording paper P passes over the corona discharge electrode 2, but as shown in FIG. It will act as a charging electrode spaced apart from 1.

That is, after the recording paper P passes over the corona discharge electrode 2,
The trailing edge of the recording paper P is detected by the sensor 9, and the sensor 9
The eccentric cam 23 is actuated by a signal from the cam 23, and the discharge wire electrode 22 is changed from the state shown in FIG. 2 to the state shown in FIG. Therefore, during charging, the discharge wire electrode 22 of the corona discharge electrode 2 is placed apart from the belt-shaped photoreceptor 1.

As described above, in the corona discharge electrode 2 of this embodiment, since the discharge wire electrode 22 is placed apart from the belt-shaped photoreceptor 1 during charging, a relatively small and uniform discharge current is generated. During transfer, the discharge wire electrode 22 is placed close to the belt-shaped photoreceptor 1, so it generates a relatively large and concentrated surface discharge current, and satisfies the performance required as a charging electrode and a transfer electrode, respectively. It's something you get.

Further, since the distance between the discharge wire electrode 22 and the belt-shaped photoreceptor 1 can be changed by the eccentric cam 23, the configuration is simple. Further, since the distance of the wire electrode 22 from the belt-like photoreceptor 1 is changed in relation to the operation of the recording paper P and the paper feeder, a predetermined state is reliably set during charging and transfer. Therefore, the corona discharge electrode can appropriately act as a charging electrode and a transfer electrode during charging and transfer.

In this embodiment, only the discharge wire electrode is provided movably, but it goes without saying that the entire corona discharge electrode may be provided movably. Further, the discharge wire electrode or the corona discharge electrode may be provided so as to be linearly movable, and may be configured to be placed at any position.

Effects of the Invention In the present invention, since the discharge wire electrode of the corona discharge electrode is configured to be able to change the distance from the image carrier, the following effects can be obtained compared to the conventional corona discharge electrode. - The magnitude and concentration of the discharge current can be adjusted, making it easy to adapt to the conditions required for a charging electrode or a transfer electrode. (2) In particular, a relatively small and uniform discharge current can be obtained during charging, and charging can be performed at a highly stable charging potential. Moreover, a relatively large and concentrated discharge current can be obtained during transfer, and transfer with good transfer efficiency can be performed. As described above, the corona discharge electrode of the present invention can satisfy both the performance required as a charging electrode and a transfer electrode. The copy image transferred to the recording paper is formed as a clear image without any fogging. ■In addition, unlike conventional corona discharge electrodes that use corotrons or scorotrons, there is no need for multiple power supply circuits, such as a high-voltage DC power supply circuit that can switch between high and low current values, or a low-voltage DC power supply circuit for grid electrodes. .

As described above, the present invention has achieved the above object with the above configuration.

[Brief explanation of drawings]

1 and 2 are schematic illustrations of an embodiment of the present invention, with FIG. 1 showing the state during charging and FIG. 2 showing the state during transfer. 1... Belt-shaped photoreceptor, 2... Corona discharge electrode. 22... Wire electrode for discharge, 23... Eccentric cam. 3...Paper feed roller, 4...Sensor.

Claims (3)

[Claims] (1) In an electrostatic recording device having a corona discharge electrode that is arranged opposite to the image carrier and serves as both a charging electrode and a transfer electrode, the distance between the discharge wire electrode and the image carrier can be changed. A corona discharge electrode for an electrostatic recording device, characterized in that it is configured as follows. (2) The wire electrode is configured to be close to the image carrier when acting as a transfer electrode, and to be disposed away from the image carrier when acting as a charging electrode. A corona discharge electrode for an electrostatic recording device according to claim 1. (3) The wire electrode is configured such that its distance from the image carrier is changed in relation to the movement of the recording paper. Corona discharge electrode of the electrostatic recording device described in .