JPS59171970A - Electrifier - Google Patents

Abstract

PURPOSE:To make the application of side erase unnecessary or reduce the application of it to reduce the fatigue of a photosensitive body by providing a means, which controls the width of electrostatic charge in a grid part of a scorotron. CONSTITUTION:When a photosensitive body 3 is laid and transferred to a position facing the electric charge discharge exit of a scorotron electrifier 1, electric charge is given to all of the surface of the photosensitive body 3. A screening plate 4 whose size is different in accordance with a desired width of electrostatic charge is divided to three plates 41, 42, and 43 and is arranged along the movement direction of the photosensitive body in each of both side ends in the lengthwise direction of the electric charge discharge exit of the scrorotron electrifier 1, and they are insulated from one another. Each of screening plates 41, 42, and 43 consists of a good electric conductor and is connected to a grid. Individual screening plates 4 are connected to a prescribed grid voltage or the earth by a changeover switch 5. When the width of electrostatic charge on the photosensitive body is changed, the changeover switch 5 is operated to change the screening plate 4 connected to the earth, thus adjusting the width.

Description

TECHNICAL FIELD The present invention relates to a PPC copying machine, and more particularly to a charging width control means for a photoreceptor in a charging device of the copying machine.

BACKGROUND OF THE INVENTION FIG. 1A is a perspective view showing the relationship between a conventional scorotron charger 1 and a site eraser 2 in an electrophotographic copying machine, and 3 is a photoreceptor. 1 Scorotron charger 1
, the photoreceptor 3 moves facing the charge emitting port.
Among these charges on the photoreceptor, there are some charges that should be removed before development depending on the paper size, etc. , typically these charges are the first (
a) The site erase 2 installed near each side edge on the downstream side in the direction of movement of the photoreceptor 3 shown in the figure illuminates the surface of the side edge of the photoreceptor to dissipate and remove the charge 4 However, this method results in fatigue in areas of the photoreceptor that are not used for development. 1st(b)
The figure shows the above-mentioned Scorotron charger 1 viewed from the charge discharge port side, and two charge wires inside the case are visible through a multi-wire grid stretched parallel to the discharge port.

The present invention has been developed in order to eliminate the drawbacks of the Juto device described in Section 2. In a device using a scorotron charger as a charging device, the present invention has been developed to suppress the charging + ij on the scorotron grid 61S. The purpose of this is to alleviate the fatigue of the Ig9 body by reducing or reducing the apprehension of site erasing. , Structure: The present invention improves the performance of the photoreceptor by not applying electricity to the area of the photoreceptor that is not used for development from the beginning during the charging stage, or by at least suppressing the amount of electricity to a small amount. The following is an explanation of the embodiment, which aims to reduce fatigue as much as possible, with reference to the drawings9. FIG. 1 is a perspective view of a scorotron charger 1, in which when a photoreceptor 3 is installed and transferred facing its charge emitting port, charges are applied to the entire surface of the photoreceptor 3. FIG.

FIG. 6(b) is a plan view of the scorotron charger 1 seen from the charge discharge port side, particularly showing its grid structure.
'Shielding plates 4 of different sizes are installed in parallel. The shielding plate 4 is divided into three parts (41, 42 and 430) having different sizes, arranged along the direction of movement of the photoreceptor, and insulated from each other. Each shielding plate 41. ．． 42 and 4
3 are made of good electrical conductors, each connected to a grid.

The changeover switch 5 connects each shield plate 4 to the constant grid voltage D1 or to ground 1. Therefore, as shown in FIG. 2(b), the switch 5 connects the shield plate 4 and 43 are connected to the ground, the grids connected to the shielding plates 42 and 43 are also grounded, so the grid is stretched and the charge emitted at the point rL is emitted from the photoreceptor. No charge is given1
．． On the other hand, since the grid voltage is applied to the shielding plate 41, the shielding plate 41 phase! According to 11J between L, the charge is scattered on the photoreceptor 6 degrees, that is, as shown in the figure, the charge is placed on 'i' with the desired width north of the photoreceptor. 1 degree charge on the photoreceptor If you want to change the width of the 14", connect it to the ground by operating the changeover switch 5. If you change the shielding plate 42.41, you can adjust the width. The shape of the switch 4 may be freely changed as necessary.1, and the changeover switch is not limited to the slide type shown in the figure, but it goes without saying that it can be changed to various types.

Furthermore, the electrical charges shown in the figure/'mi use the 10 symbol, but the effect is the same either way.

Since the charge on the photoconductor 11 can be adjusted arbitrarily by using this configuration, it is possible to greatly reduce the charge on the edge of the photoconductor 1111, which stabilizes the site erase, and eliminates unnecessary erase. 1. Since the effects are as described above, the present invention is 2. capable of reducing photoreceptor fatigue in this type of device compared to conventional ones. It can be used not only for PPC copying machines, but also for facsimiles, laser beam printers, etc.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view of a main part of a charging device using a conventional scorotron charger in an electrophotographic copying machine, and FIG.
) is a partial view of the scorotron charger seen from the charge emitting port side j, and FIG. 2(a) is a perspective view of the main parts of the device of the present invention.
FIG. 2(b) is a conceptual diagram of the charge emitting capacitor of the scorotron charger provided in the device of the present invention and its fluoride width control mechanism. 1... - Scorotron charger, 2... Site erase, 3... Photoreceptor, 4... Shielding plate, 5...
...Selector switch, HV...High voltage power supply agent Patent attorney Makoto Kon

Claims (3)

[Claims] (1) Scorotron as a charging device for electrophotographic copying machines
A charging device using a meter power type, characterized in that means for controlling charging [I] of a single photoreceptor moving facing the device is provided on the lid side of the scorotron charger. 1゜ (2) In the scorotron charger, the phantom J! on the photoreceptor! , j, a plurality of sets of grids, and a means for grounding a grid other than the desired charging width behind the knot part. Device. (3) At least one side edge area of the charge emitting port of the charger is provided with a plurality of pieces having different widths so as to impart a specific charge to the photoreceptor moving facing the charge emitting port. Mutually insulated shielding plates and grids connected to the respective grids are arranged in parallel, and each of the grids is provided with means for switching the voltage applied to each grid, 0 or a predetermined grid voltage, through the i-main shielding plate. The charging device according to claim 2, characterized in that: