Organic photoconductor drum having an overcoat containing nano metal oxide particles and method to make the same
An improved organic photoconductor drum having a protective overcoat layer and method to make the same is provided. The protective overcoat layer is prepared from a curable composition including nano metal oxide particles sized less than 400 nm in combination with an urethane acrylate resin having at least 6 functional groups.
1. A method of preparing an organic photoconductor drum comprising:
providing an electrically conductive substrate;
preparing a charge generation layer dispersion:
coating the charge generation layer dispersion over 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 an overcoat layer formulation including:
about 70 percent to about 95 percent by weight of a urethane acrylate resin having at least six radical polymerizable functional groups;
about 5 percent to about 30 percent by weight of indium tin oxide particles sized less than 200 nm; and
an organic solvent;
coating the overcoat layer formulation over the charge transport layer; and
curing the overcoat layer formulation to form a photoconductor having an overcoat layer over the charge transport layer and the charge generation layers, wherein the overcoat layer does not include charge transport materials.
2. The method of claim 1 , wherein the urethane acrylate resin having at least six radical polymerizable functional groups is a hexa-functional aromatic urethane acrylate resin having the following structure:
3. The method of claim 1 , wherein the urethane resin having at least six radical polymerizable functional groups is a hexa-functional aliphatic urethane acrylate resin having the following structure:
4. The method of claim 1 , wherein the overcoat layer is cured by an electron beam.
5. The method of claim 4 , wherein the cured overcoat layer has a thickness of about 0.1 μm to about 10 μm.
6. The method of claim 1 , wherein the overcoat layer formulation further includes a monomer or oligomer having at most five radical polymerizable functional groups.
7. The method of claim 1 , wherein the overcoat layer formulation further includes a coating aid additive at an amount equal to or less than about 10 percent by weight of the curable composition.
8. The method of claim 7 , wherein the amount of the coating aid additive is about 0.1 to about 5 percent by weight of the curable composition.
9. The method of claim 7 , wherein the coating aid additive is a surfactant.