International Business Machines Corporation

Paul D Jachimiak

Jerry J Abbott

Sterritt R Fuller

Alvin L Wittwer

Ronald E Gaitten

James A Machmer

Stephen C Crossan

A developer material comprising toner particles and coated carrier beads for use in developing images in an electrostatographic device is disclosed. The toner particles are initially classified according to a size distribution wherein less than 15% by weight are greater than 16 microns, between 7 and 15% by weight are less than 5 microns, the remainder being from 5 to 16 microns; and wherein the median particle size by weight is from 8 to 12 microns. The carrier beads have a core with a coating thereon. The coating is a mixed resin system comprising 5 to 55% by weight polytetrafluoroethylene, 5 to 55% by weight fluorinated polyethylene-propylene, and 40% to 80% by weight of a poly(amide-imide) resin which is stable up to at least 600.degree. F., triboelectrically negative (with respect to the herein described toner), nonspalling, essentially nonfriable and dispersible with the other resin components. Also, preferably the coating includes a pigment, such as TiO.sub.2, dispersed in the resin system. More specific ranges of size classification of the toner particles and preferred ranges of resin components are also disclosed.

Electrophotographic toner and carrier

A toner material for use in developing images in an electrostatographic device is disclosed. The toner particles are initially classified according to a size distribution wherein less than 15% by weight are greater than 16 microns, between 7 and 15% by weight are less than 5 microns the remainder being from 5 to 16 microns and wherein the median particle size by weight is from 8 to 12 microns. The toner is used in a developer mix with carrier particles, and preferably the toner carrier mix is equilibrated such that the action of the developer mix and the machine provide a toner particle size distribution wherein less than 12% by weight are greater than 16 microns, between 15 and 30% by weight are less than 5 microns, the remainder being from 5 to 16 microns, and wherein the median particle size by weight is between 6.5 and 9.5 microns. An equilibrated toner particle distribution is also disclosed.

Electrophotographic toner of specific size distribution

An improved backup roll for use in the heated fuser system of electrostatic copy machines wherein the fuser system employs a fuser roll couple comprised of a heated fuser roll in pressure contact with the backup roll. In construction, the backup roll includes an aluminum core member with a coating of polyurethane reinforced flourinated ethylene propylene on its surface. The coating has heat transfer characteristics similar to the copy sheets fed through the couple so as to withdraw heat from the heated fuser roll, along each zone where it may make direct contact with it, at substantially the same rate as the copy sheets withdraw heat. The coating also has a thickness whereby the heat transferred to each zone during contact with the fuser roll is quickly transferred to the aluminum core before that zone again contacts the fuser roll.

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Lafayette, CO, United States of America

Paul D Jachimiak