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Carrier for Use with an Automatic Toner Concentration Control System

IP.com Disclosure Number: IPCOM000082317D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

McAninch, MF: AUTHOR [+5]

Abstract

A steel shot of the desired size is coated in a fluidized bed coating tower, by levitating the steel shot in an upwardly moving air stream of elevated temperature. The coating material is atomized through a nozzle and fed into the air stream, such that each of the beads in its random motion within the coating apparatus acquires a thin coating of the coating material. The primer material for this carrier is Du Pont TEFLON* 850-302 white TEFLON primer. This is a polytetrafluoroethylene, chromic and phosphoric acid mixture, in water and is pigmented with titanium dioxide.

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Carrier for Use with an Automatic Toner Concentration Control System

A steel shot of the desired size is coated in a fluidized bed coating tower, by levitating the steel shot in an upwardly moving air stream of elevated temperature. The coating material is atomized through a nozzle and fed into the air stream, such that each of the beads in its random motion within the coating apparatus acquires a thin coating of the coating material. The primer material for this carrier is Du Pont TEFLON* 850-302 white TEFLON primer. This is a polytetrafluoroethylene, chromic and phosphoric acid mixture, in water and is pigmented with titanium dioxide.

A top coating of a TEFLON material sold under the name of Du Pont TEFLON 852-201 TEFLON enamel is coated onto the bead. The bead is then cured in an oven at an elevated temperature, such that the polytetrafluoroethylene particles of the TEFLON coating fuse together to cause a continuous coating of the material. The white pigmentation increases the signal- to-noise ratio inasmuch as the white is a better background to judge the concentration of black toner against, rather than the steel gray of steel shot.

The TEFLON is coated onto the outer surface of the bead in an unpigmanted layer to prevent the pigmentation from presenting itself at the surface, and thus effecting triboelectrical properties of the carrier bead. Further, the pigmentation is maintained in the primer coating so as to not provide potential sites for fused on toner...