Browse Prior Art Database

BIAS ROLL TRANSFER WITH LIGHT EXPOSURE THROUGH THE PHOTOCONDUCTOR, IN AND PAST THE ROLL NIP

IP.com Disclosure Number: IPCOM000025971D
Original Publication Date: 1989-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 129K

Publishing Venue

Xerox Disclosure Journal

Abstract

Bias roll transfer (BTR) systems provide pressure engagement between a copy substrate and toner layer, while creating the transfer field necessary for transfer of toner to the copy substrate. Because of this pressure engagement, BTR systems may solve problems caused by air gaps at the tonerlsubstrate interface when cockled, curled, or other non-flat substrate material is used. For BTR systems to work, it is important to provide a high transfer field in and just past the roller nip, but the allowed fields are typically limited by air breakdown in the area before the transfer ni , often resulting in an image

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XEROX DISCLOSURE JOURNAL

I 16

BIAS ROLLTRANSFER WITH Proposed Classification LIGHT EXPOSURE THROUGH THE PHOTOCONDUCTOR, IN AND PAST
THE ROLL NIP
Gerald M. Fletcher

us. c1.355/3 Int. C1. G03g 15/00

14

/ 24

20 -

Volume 14 Number 3 May/June 1989 123

[This page contains 1 picture or other non-text object]

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BIAS ROLL TRANSFER WITH LIGHT EXPOSURE THROUGH THE PHOTO- CONDUCTOR, IN AND PASTTHE ROLL NIP (Cont'd)

Bias roll transfer (BTR) systems provide pressure engagement between a copy substrate and toner layer, while creating the transfer field necessary for transfer of toner to the copy substrate. Because of this pressure engagement, BTR systems may solve problems caused by air gaps at the tonerlsubstrate interface when cockled, curled, or other non-flat substrate material is used. For BTR systems to work, it is important to provide a high transfer field in and just past the roller nip, but the allowed fields are typically limited by air breakdown in the area before the transfer ni , often resulting in an image

intimately engaged with the toner image in the pre-nip zone.

A low pressure engagement of the biased roll and substrate has previously been considered desirable, to minimize hollow character defects. In the past, soft biased rolls have been used for this purpot-e. However, the soft rolls present a problem in cleaning toner acquired at the interdocument area from the roll surface. Generally, brush cleaners have been required for cleaning the rolls, instead of relatively low cost blade cleaners.

With reference to the Figure, a hard biased roll is provided in a BTR system. Biased roll 10, a hard conductive roll biased to provide an appropriate transfer field, is loaded against a tensioned photoconductive belt 14 in a manner providing a desirable nip pressure engagement and wrap. An exposure lamp 16 shines through the transparent photoconductive belt 14, from the rear side of the belt, illuminating the area in and beyond the start of the BTR nip. A simple cleaning blade...