Browse Prior Art Database

Printer/ Copier Photoconductor Electrostatic Sensor

IP.com Disclosure Number: IPCOM000049950D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Witcher, LD: AUTHOR

Abstract

Electrophotographic apparatus is described having a magnetic brush developer which includes at least one developer roll which is electrically isolated so that the developer roll can be used to sense the voltage developed on the roll during operation of the electrophotographic apparatus.

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 84% of the total text.

Page 1 of 2

Printer/ Copier Photoconductor Electrostatic Sensor

Electrophotographic apparatus is described having a magnetic brush developer which includes at least one developer roll which is electrically isolated so that the developer roll can be used to sense the voltage developed on the roll during operation of the electrophotographic apparatus.

The electrophotographic apparatus includes a drum 15 having a photoconductor 14 on its peripheral surface. The magnetic brush developer 10 comprises a plurality of magnetic brushes 12 each provided with electrically isolated mounting adjacent to the photoconductor 14 which carries a latent image to be developed. A power source 16 is provided to impress a preselected voltage on each of the magnetic brushes 12 by connection to a terminal 18 which extends outside developer housing 20 during normal operation of the electrophotographic apparatus.

A switching means 21 is provided for at least one of the developer rolls 12 for operation during a test mode position (shown dotted in the drawing) to electrically isolate the developer roll. During the test mode, the photoconductor is charged, the photoconductor drum 15 is driven at normal speed, and the normal developer flow is provided through the magnetic brush developer. This action develops a voltage V(t) on the developer roll 12 selected for the test mode which is proportional to the charge level on the photoconductor, and this voltage level is sensed by voltage sensing means 22. By pe...