JPS61117583A - Transferring device of dielectric belt - Google Patents

Abstract

PURPOSE:To reduce the number of corona generators and power source devices used in the titled transferring device so as to make the transferring device compacter, by using scorotron for at least the electricity removing coronona discharger of a transferring and electricity removing corona dischargers and forming the power sources for both the corona generating means of a single high-voltage power source. CONSTITUTION:A grid electrode 15 is provided at the opening of an electrisity removing corona discharger 6 as a scorotron. A DC is used as the high-voltage power source for generating corona and a common high-voltage power source 14 is used not only for the corona generation but also for the high-voltage power soruce for a transferring corona discharger 5. Moreover, the electrode 15 is grounded through, for example, a varister for 200V and no corona discharger for charging a belt 2 and its high-voltage power source are provided. Though the dielectric belt 2 still has residual charges and minus charges are induced on the surface of the belt 2 by the transferring corona even after transferring operations are completed, (+) corona charges are added to the surface of the belt 2 through the electrode 15, since the scorotron is used as the corona discharger 6. Moreover, since the electrode 15 is grounded through the varister 16, the surface side of the belt 2 is charged to +200V and, therefore, a charging device can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a transfer device of an electrostatic copying apparatus having a dielectric belt transfer device.

Prior Art A device that transfers a toner image formed on a photoreceptor to a transfer paper through a predetermined electrostatic photographic process is a device that is rotated with its outer peripheral surface in contact with the surface of the photoreceptor at the transfer position, and is charged by a belt charger. Transfer paper is attracted to the outer peripheral surface of the dielectric belt and conveyed, a transfer device is provided on the back side of the dielectric belt, and a transfer electric field is formed between the transfer paper P and the transfer position of the photoreceptor. 2. Description of the Related Art A dielectric belt transfer device that transfers a toner image on a photoreceptor to a transfer paper is known.

With this transfer method, the electrostatic attraction force between the transfer paper and the belt ensures stable adhesion, so the separation of the paper from the photoreceptor after transfer is reliable.Furthermore, since the paper does not shift relative to the belt, it is possible to This method is effective for color copying, etc., in which a transfer paper is sequentially brought into contact with a photoconductor to perform superimposed transfer.

A general example of a dielectric belt transfer device will be explained with reference to FIG. 5. A belt 2 made of a dielectric material such as Mylar film is rotated so that its outer peripheral surface contacts the transfer position on the surface of the photoreceptor drum 1. is wound around the drive roller 3 and the separation roller 4, and is driven in the direction shown by the arrow. A transfer corona device 5 is placed between the belt 2 at the transfer position and facing the photosensitive drum 1.
is provided, and high voltage is applied to the corona wire by a high voltage power source 9 for transfer. A belt charger 7 to which a high voltage is applied by a belt charging high voltage power source 11 is provided on the outside of the belt wound around the drive roller 3, so that the charged dielectric belt is fed with paper from the paper feed section. The transfer paper 12 is electrostatically attracted, and the toner image formed by a predetermined electrostatic photographic process on the photoreceptor drum 1, which is conveyed to the transfer section as the belt 2 rotates, is transferred by a transfer corona from the back side of the belt. It is transferred onto the surface of the transfer paper 12 under the transfer electric field generated by the device 5.

After the transfer, the transfer paper 12 is separated by the rigidity of the transfer paper itself and the separation roller 4.
It is separated from the belt 2 in relation to the curvature of , and is conveyed to a fixing device (not shown) and fixed, thereby completing the copying. On the other hand, a static eliminator 6 is provided facing the belt surface between the separation roller 4 and the drive roller 3.
Then, the counter electrode 13, which is provided to sandwich the belt 2 and face the static eliminator corona device 6, forms a static eliminator W, and the transfer paper 1
The residual charge on the dielectric belt 2 that separated the two is removed.

Furthermore, a cleaning blade 8 is provided in contact with the outer circumferential surface of the belt 2 at the position where it begins to contact the drive roller 3, and the toner adhering to the belt surface outside the portion where the transfer paper 12 is positioned is thereby removed.

Here, as described above, an AC power source is used as the power source 10 of the static eliminator corona device 6, and the power source 11 of the belt charger 7 for electrostatically attracting the transfer paper 12 to the dielectric belt 2 is used.
For example, the potential of the dielectric belt 2 is +2 when measured from the front side.
It is a high voltage DCII source that has a predetermined value of 00V or more. Therefore, the conventional transfer device has three corona generators, and its high-voltage power supplies include one AC and two DC power sources, resulting in an increase in the size of the device and high cost.

Purpose: In view of the above-mentioned drawbacks of the conventional electrostatic copying apparatus using a dielectric belt transfer method, the present invention provides a compact and low-cost dielectric belt transfer system with a small number of corona generators and their power supply devices. The purpose is to provide equipment.

Structure: In order to achieve this object, the first aspect of the present invention is that in the dielectric belt transfer device having the above-mentioned structure, at least the static eliminating corona device of the transfer corona device and the static eliminating corona device is a Suflotron. In addition, the present invention is characterized in that the power sources for both of these corona generating means are a single high-voltage power source.

Further, in the second aspect of the present invention, the transfer corona generating means and the static eliminating corona generating means each have a grid having an opening on a surface opposite to the single corona wire, and these grids are used for transfer of the dielectric belt. The present invention is characterized in that one scorotron connected to one high-voltage power source disposed opposite to the static elimination position and the static elimination position serves both purposes.

Hereinafter, the present invention will be described in detail based on drawings showing embodiments thereof.

FIG. 1 shows a first embodiment of the present invention, in which a static eliminator corona device 6
A grid 15 is provided at the opening of the scorotron, and the high voltage power source for corona generation is direct current, and a high voltage power source 14 that is common to the high voltage power source for the transfer corona device 5 is used. Further, in this embodiment, the grid electrode 15 of the static eliminating corona device is, for example, a varistor (constant voltage element) 1 for 200V.
It is grounded via 6. Further, a corona device 7 for belt charging and a high voltage power source for it are not provided.

After the transfer, the dielectric belt 2 has a residual charge due to the transfer corona, and a negative charge is induced on the front side of the belt 2. However, since a scorotron is used as the charge eliminating corona device 6, the grid electrode 15 is Since a positive corona charge is applied to the front side of the belt 2 through the capacitor and the grid electrode is grounded via a 200V varistor, the front side of the belt 2 is charged to approximately +200V.

The +200V charge is sufficient to attract the transfer paper, so the belt charging device can be omitted, and the use of a common high-voltage power source for transfer and removal reduces the overall cost and cost of the device. You can aim for down. Note that the varistor 16 may be a bias power source, and if the transfer corona device 5 is also a scorotron, the potential of the belt can be easily controlled.

FIG. 2 is a diagram showing a second embodiment of the present invention.

In the transfer device of this embodiment, the transfer corona generating means and the static eliminating corona generating means are not separately provided, but a single corona wire 17 and grids 18° provided in two openings provided on opposite sides are used. One scorotron 2o having 19 is used, and the grid 18 is arranged to face the back side of the transfer position of the belt 2, and the grid 19 is arranged to face the static elimination position. An AC power source is used as the high voltage power source 21 that applies voltage to the corona wire 17,
Each of the grids 18 and 19 is connected to the grid 181 by inserting one-way diodes 22 in opposite directions and grounding them.
From 19, corona discharge currents of opposite polarity are discharged, which are necessary for transfer and charge removal, respectively, and it becomes possible to perform transfer and charge removal at the same time.

Furthermore, as shown in FIGS. 3 and 4, a scorotron 2° having the above-mentioned two openings and a grid, and a high voltage power source 21 are installed.
If these are arranged as one unit inside the loop of the dielectric belt 2, the corona generating device can be easily taken out, and the dielectric belt transfer device can be made into a magazine, which is convenient for maintenance and replacement. .

Effects As described above, according to the present invention, it is possible to reduce the number of corona generators and their high-voltage power supplies required for a dielectric belt transfer device, which is effective in making the entire device more compact and reducing costs. can get.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a first embodiment of the present invention, Fig. 2 is a sectional view showing a second embodiment of the invention, Fig. 3 is a sectional view showing a modified embodiment thereof, and Fig. 4 is a sectional view thereof. The perspective view and FIG. 5 are cross-sectional views showing the structure of a conventional dielectric belt transfer device. 1... Photoreceptor, 2... Dielectric belt, 5... Transfer corona device, 6... Static eliminator corona device, 12... Transfer paper, 14... Dual use for transfer corona device and static eliminator corona device High voltage power supply, 15/18.19... Grid, 16... Constant voltage element (varistor), 17... Corona wire,

Claims (4)

[Claims] (1) At the transfer position of the toner image formed on the photoreceptor, the outer peripheral surface contacts the outer peripheral surface of the photoreceptor and rotates, and the fed transfer paper is attracted to the outer peripheral surface to the above-mentioned transfer position. an endless dielectric belt for transporting the toner image, a transfer corona generating means for applying a corona charge of opposite polarity to the toner image to the back surface of the dielectric belt at the transfer position, and separating the transfer paper from the dielectric belt after the transfer. In a transfer device of an electrostatic copying apparatus having a charge-eliminating corona generating means for imparting a corona charge to the dielectric belt in order to eliminate residual charges on the rear dielectric belt, the transfer corona generating means and the charge-eliminating corona generating means may be used. A transfer device characterized in that at least the static eliminating corona generating means is a scorotron, and the power source for both of these corona generating means is a single high voltage power source. (2) The transfer device according to claim 1, wherein the grid electrode of the scorotron serving as the static elimination corona generating device is grounded via a constant voltage element. (3) At the transfer position of the toner image formed on the photoreceptor, the outer peripheral surface contacts the outer peripheral surface of the photoreceptor and rotates, and the fed transfer paper is attracted to the outer peripheral surface to the above-mentioned transfer position. an endless dielectric belt for transporting the toner image, a transfer corona generating means for applying a corona charge of opposite polarity to the toner image to the back surface of the dielectric belt at the transfer position, and separating the transfer paper from the dielectric belt after the transfer. After that, in a transfer device of an electrostatic copying apparatus having a charge eliminating corona generating means for imparting a corona charge to the dielectric belt in order to eliminate residual charges on the dielectric belt, the transfer corona generating means described above and the charge eliminating corona generating means described above are used. The means includes a single corona wire and a grid having an opening on the opposite side, and these grids are arranged opposite to the transfer position and the neutralization position of the dielectric belt, and are driven by a single high-voltage power source. A transfer device characterized in that one scorotron is used for both purposes. (4) The transfer device according to claim 3, wherein the corona discharger and its high-voltage power source are arranged inside a loop of a dielectric belt.