Lexmark International, Inc.

Catherine Mailhe Randolph

Kasturi Rangan Srinivasan

Mark Thomas Bellino

Ronald Harold Levin

Scott Thomas Mosier

Jennifer Kaye Neely

Gregory Walter Haggquist

Laura Lee Kierstein

Paul Dwight Kemmesat

Sterritt R Fuller, Jr

Methods of making a charge generation layer comprise premixing a charge generation compound, a charge transport compound and solvent to form a premix essentially free of polymeric binder, mixing the premix with at least one polymeric binder to form a dispersion, and coating the dispersion on a substrate. Photoconductors comprising a substrate, a charge transport layer and a charge generation layer formed by such a method exhibit improved electrical sensitivity.

Methods of making charge generation layers containing charge transport

The invention described in the specification provides an improved coating for an electrophotographic photoconductor printing system. In particular, a blend of polycarbonate-A and polycarbonate-Z binders according to the formula: ##STR1## wherein R.sup.1 is selected from the group consisting of CH.sub.2 an alkylidene group, a cycloalkyl group and a substituted cycloalkyl group, R.sup.2 and R.sup.3 are selected from the group consisting of hydrogen, halogen and an a CH.sub.3 group provides increased durability and wear properties to a charge transport layer coated onto a charge generation layer of a photoreceptor drum. The polycarbonate blend may be used with amine and hydrazone charge transport materials and the charge transport layer may include additional additives which further improve the wear properties of the photoconductor coatings in a laser printer.

Electrophotographic photoconductors

Photoconductors comprise a substrate, a charge transport layer and a charge generation layer, wherein the charge transport layer comprises binder and a first charge transport compound and the charge generation layer comprises binder, a charge generation compound and a second charge transport compound. The first and second charge transport compounds may be the same or different. In a first embodiment, the second charge transport compound is effective as a dopant in the charge generation layer and the weight ratio of the charge generation compound to the second charge transport compound in the charge generation layer is not less than about 1:3. In a second embodiment, the charge generation layer is formed on the substrate and the charge transport layer is formed on the charge generation layer. In a third embodiment, the charge generation layer comprises at least about 15 weight percent, based on the weight of the charge generation layer, of the charge generation compound.

Dual layer photoconductors with charge generation layer containing

Titanium dioxide added to oxo-titanyl phthalocyanine in a resin binder forming a charge generation layer having significantly improved dark decay and sensitivity. Added sensitivity is obtained when the X-form is precipitated from a dichloromethane/trifluoroacetic acid/oxo-titanyl phthalocyanine mixture by adding a water/methanol mixture containing titanium dioxide.

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Niwot, CO, United States of America

Catherine Mailhe Randolph