Lexmark International, Inc.

Jeffery R Brener

Donald Wayne Stafford

Martin Victor DiGirolamo

Peter W Bracken

Peter E Wallin

Sam E Mullinix, Jr

Samuel Edward Mullinix, Jr

Steven L Applegate

Peter Eric Wallen

A conductive paste comprising a flexible elastomer, an electrically conductive particulate material and, optionally, a solvent is disclosed. This paste is used for providing flexible, electrically conductive bonding between materials. In a preferred embodiment, conductive paste of the present invention is used in a flexible doctor blade to provide bonding and an electrical connection between the support member and the portion of the blade which contacts the developer roller.

Electrical contact material for flexible doctor blade

A compliant doctor blade has a metal bar (13) with bottom attached by dual side adhesive tape (15) to a resilient layer of porous foam (7). The bottom of the foam layer is attached by dual side adhesive tape (8) to a shim (1), which is stiff in the direction of movement of the roller (9) which the shim contacts. The shim has a polyester body (3) and a bottom layer (5) containing abrasive grit and conductive carbon black. Finally, the end of the doctor blade is dipped in a conductive paste which hardens into a conductive coating (17) which bridges the conductive layer of the shim and the metal bar. Advantages are reduced costs and improved performance, particularly with respect to streaks from prenip packing.

Abrasive shim compliant doctor blade

The conductive film (3) of a compliant doctor blade has dispersed particles of molybdenum disulfide, as well as dispersed particles of grit and conductive filler. The molybdenum disulfide eliminates filming of toner. The molybdenum disulfide may be a surface powder since the anti-film action occurs at the pre-nip and therefore is not lost by the molybdenum disulfide wearing away at the nip.

Compliant doctor blade surface having molybdenum disulfide

A compliant doctor blade having excellent toner metering capabilities is disclosed. The doctor blade includes a compliant laminate (3) having a resin film backing layer and carrying a binder which contains abrasive particles, such as silicon carbide particles, and a conducting means. In a preferred embodiment the conducting means are conductive carbon black particles which are contained in the resin binder which also includes the abrasive silicon carbide. The compliant laminate is supported on an aluminum bar (1). The bar has fastened to its bottom face a compliant foam layer (2) which includes on its bottom face a shim (10) having a stiffness of from about 0.5 to about 31.0 inches of deflection/inch of length/pounds of force. The laminate is bent under the foam layer and shim where it contacts the developer roller (6). The conductive layer remains conductive as it wears during use. In addition, this doctor blade minimizes toner buildup in the prenip area and provides effective and uniform metering of the toner on the developer roller.

Compliant doctor blade

Doctor blade 1 has a compliant lamination (4) having a resin film backing layer (4a) and conductive layer (4b) abrasive silicon carbide particles and conductive carbon black in a resin binder. The compliant lamination is supported on an aluminum bar 2, having a downwardly extending wall 2b. In use lamination 2 is bent under the support bar at the end of the wall, a direct turn which avoids a wedge configuration where the lamination contacts the developer roller (7). The conductive layer remains conductive as it wears during use and the avoidance of the wedge prevents a build-up of toner at the nip during use, both of which make possible long effective useful operation of this doctor blade.

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Lexington, KY, United States of America

Jeffery R Brener