Browse Prior Art Database

Leading Edge Erase

IP.com Disclosure Number: IPCOM000081769D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Brandon, FY: AUTHOR [+2]

Abstract

In a xerographic copier having a magnetic brush developer unit 10 including a development electrode 11 and a heated roll fuser 12, it has been found that dense toner images adjacent the leading edge of transfer sheets 13 have a tendency to adhere to the heated roll fuser 12. An optical system such as a scanning mirror system 14 receives light reflected from an object 15 on a window 16, as reflected from a light source 17.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 70% of the total text.

Page 1 of 2

Leading Edge Erase

In a xerographic copier having a magnetic brush developer unit 10 including a development electrode 11 and a heated roll fuser 12, it has been found that dense toner images adjacent the leading edge of transfer sheets 13 have a tendency to adhere to the heated roll fuser 12. An optical system such as a scanning mirror system 14 receives light reflected from an object 15 on a window 16, as reflected from a light source 17.

No light will be reflected in regions of the window 16 not covered by the object 15. Thus where the object 15 does not cover a portion 18 of the window 16 adjacent the edge of the image area, an undischarged portion of the copy drum 9 will be presented to developer unit 10 where a dense toner image will be formed. This toner image will be transferred to the leading edge of sheet 13, thus creating a possible failure here at roll fuser 12 as described above.

For copying thin documents such as single sheets 13, a light colored cover 19 is ordinarily provided to reflect light through lens 14 and discharge areas not covered by a small document. Such a cover cannot be adequately closed on a thick object 15. A switch 20 is provided to detect when cover 19 is open and in such case, controls relay 21 to connect the bias lead to magnetic brush development electrode 11 to a high-bias level of the same polarity as the initial charge on the photo-conductor.

Relay 21 is dropped upon closure of switch 22 by a cam 23 rotating with photoconduc...