Photoconductor overcoat having a radical polymerizable charge transport molecule containing two ethyl acrylate functional groups and urethane acrylate resins containing six radical polymerizable functional groups
View Patent ↗An improved overcoat layer for an organic photoconductor drum of an electrophotographic image forming device is provided. The overcoat layer is prepared from a curable composition including a triphenylamine charge transport containing two ethyl acrylate functional groups and a urethane resin containing six radical polymerizable functional groups. The amount of the triphenylamine charge transport containing two ethyl acrylate functional groups in the curable composition is about 20 to about 80 percent by weight. The amount of the urethane resin containing six radical polymerizable functional groups in the curable composition is about 20 to about 80 percent by weight. This overcoat layer improves wear resistance of the organic photoconductor drum without negatively altering the electrophotographic properties, thus protecting the organic photoconductor drum from damage and ultimately providing a photoconductor with a longer useful life when compared to other organic photoconductors commercially available.
1. A method of preparing a photoconductor comprising:
providing an electrically conductive substrate;
preparing a charge generation layer dispersion;
coating the charge generation layer dispersion onto the electrically conductive substrate to form a charge generation layer;
preparing a charge transport layer dispersion;
coating the charge transport layer dispersion over the charge generation layer to form a charge transport layer;
preparing a protective overcoat layer formulation, the protective overcoat layer being formed from a curable composition including:
about 20 to about 80 percent by weight of a triphenylamine charge transport molecule containing two ethyl acrylate functional groups as shown below:
wherein R is selected from the group consisting of H and an alkyl group; and
about 20 to about 80 percent by weight of a urethane acrylate resin containing six radical polymerizable functional groups, an organic solvent and a photoinitiator,
coating the protective overcoat layer formulation over the charge transport layer; and
curing the protective overcoat layer formulation to form a photoconductor having a protective overcoat layer over the charge transport layer and the charge generation layers.
2. The method of claim 1 , wherein the curable composition includes:
about 40 to about 60 percent by weight of a triphenylamine charge transport molecule containing two ethyl acrylate functional groups; and
about 40 to about 60 percent by weight of a urethane acrylate resin containing six radical polymerizable functional groups.
3. The method of claim 1 , wherein R is a hydrogen atom.
4. The method of claim 1 , wherein R is an alkyl group containing 1 to about 6 carbon atoms.
5. The method of claim 1 , wherein the urethane resin of the urethane resin containing six radical polymerizable functional groups is an aliphatic urethane resin.
6. The method of claim 1 , further comprising the step of adding a non-radical polymerizable additive to the curable composition.
7. The method of claim 1 , wherein the protective overcoat layer has a thickness of about 0.1 μm to about 10 μm upon curing.