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A COROTRON DEVICE WHOSE CURRENT OUTPUT CAN BE VARIED IN A PRESCRIBED WAY WITH TIME

IP.com Disclosure Number: IPCOM000024069D
Original Publication Date: 1979-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 242K

Publishing Venue

Xerox Disclosure Journal

Abstract

In the process known as detacking, it is useful to be able to deposit relatively more charge on the lead edge of a copy than on the bulk of the copy. This facilitates detacking at the same time as minimizing toner image disturbances. To do this it is necessary to have a signal derived from the paper position. If the current switching is performed with relays, there are intrinsic difficulties in obtaining current variations of very short duration and in shaping the form of the current variation with time associated with the essentially mechanical operation of relays. If the switching is accomplIshed purely electronically, these difficulties are easily overcome.

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XEROX DISCLOSURE JOURNAL

A COROTRON DEVICE WHOSE CURRENT Proposed Classification ~iJTPUT CAN BE VARIED IN A PRESCRIBED U.S. CL 355/3 CH _______________ mt. Cl, G03g 15/00
B. E. Springett

In the process known as detacking, it is useful to be able to deposit relatively more charge on the lead edge of a copy than on the bulk of the copy. This facilitates detacking at the same time as minimizing toner image disturbances. To do this it is necessary to have a signal derived from the paper position. If the current switching is performed with relays, there are intrinsic difficulties in obtaining current variations of very short duration and in shaping the form of the current variation with time associated with the essentially mechanical operation of relays. If the switching is accomplIshed purely electronically, these difficulties are easily overcome.

The figure shows a circuit which avoids the need for switching between separate power supplies at the level of a thousand volts and further provides a way to tailor the current variation to match the complex interaction between the corotron device, the paper edge, the detacking function and toner disturbances. In the figure, AC supply 2 provides voltage Vw to a dieIectric~coated wire (dicorotron) 3 which is to apply charge to a surface 4. Shield 5 is biased by DC voltage Vs applied by supply 6.

The charging current i delivered to surface 4 is equal to the current flowing in the shield circuit and may, thus, be controlled by...