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Controlling Toner to Carrier Concentration in an Electrophotographic Copier

IP.com Disclosure Number: IPCOM000074496D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Simpson, HW: AUTHOR [+3]

Abstract

Toner carrier concentration in a developer mixture is measured by automatically controlling the amount of toner on an individual carrier bead so that each toner particle has a minimum total body charge.

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Controlling Toner to Carrier Concentration in an Electrophotographic Copier

Toner carrier concentration in a developer mixture is measured by automatically controlling the amount of toner on an individual carrier bead so that each toner particle has a minimum total body charge.

Control of toner to carrier concentration in a copier is necessary to maintain the charge level of the toner in the machine to prevent toner clouding and provide for transfer from the organic photoconductor (OPC) to the paper. The force of attraction between the toner and carrier is proportional to the charge level between them. The charge level of the toner is controlled by subjecting the carrier to excessive toner and then to subject the toner carrier system to a removing force smaller than that which would strip the desired level of charged toner. This can be done by impacting the developer at a controlled velocity, applying a centrifugal force of known magnitude and rolling the developer over another material of known triboelectric charging level.

The graphs at A and B illustrate the method. Toner carrier samples of varying concentrations are poured from two different heights to impact on a 150 mesh screen. A small air flow through the screen is used to pull the airborne toner away after impact. The graphs show the concentration of the mix after impacting on the screen as a function of the initial concentration before impact. A range of initial concentrations can be made to fall in a r...