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Carrier for Uniform Continuous Tone Development in Electrophotography

IP.com Disclosure Number: IPCOM000094791D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Woodward, DH: AUTHOR

Abstract

Continuous tone development of an electrostatic image requires a development electrode near the image. This electrode is either a conductive and non-magnetic material for use in cascade development or, in magnetic brush development, it is the magnetic brush which is a conductive and magnetic material. This electrode positions the electric field, which is formed by the electrostatic charges of the image, perpendicular to the image surface and over the whole area of the image. When this electric field is uniformly perpendicular and the lines of the field are essentially straight, uniform continuous tone development is obtained.

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Carrier for Uniform Continuous Tone Development in Electrophotography

Continuous tone development of an electrostatic image requires a development electrode near the image. This electrode is either a conductive and non-magnetic material for use in cascade development or, in magnetic brush development, it is the magnetic brush which is a conductive and magnetic material. This electrode positions the electric field, which is formed by the electrostatic charges of the image, perpendicular to the image surface and over the whole area of the image. When this electric field is uniformly perpendicular and the lines of the field are essentially straight, uniform continuous tone development is obtained.

In order to assist the development electrode in straightening the lines of the electric field and, hence, improve the quality of the developed image, the carrier, shown above, is employed. This carrier comprises core 1 of a low mass material, such as glass or plastic. Core 1 is coated with highly conductive layer 2, such as silver, copper, gold, and aluminum, preferably in that order. Layer 2, due to its conductivity, assists the development electrode in straightening the electric field of the electrostatic image and thus improves the developed image quality.

For magnetic brush development, layer 2 is coated with a ferro-magnetic material 3. If desired, layers 2 and 3 can be reversed so that layer 3 would serve as the inner layer. Layer 3 is eliminated for cascade developm...