Shaped charge generation layer for a photoconductive drum
A photoconductive drum includes an elongated support element with a shaped charge generation layer. The layer extends from the support element at various thicknesses along a length thereof. Thicker charge generation portions provides denser optical densities compared to thinner portions allowing tailoring the photoconductive drum to compensate for imperfect optical scanning systems. A charge transport layer overcoats the charge generation layer. Optionally, an oxidation layer underlies the charge generation layer as does a protective overcoat overlying the charge transport layer. Various thicknesses and shapes of the charge generation layer are also disclosed.
1. A photoconductive drum, comprising:
an elongated support element having a surface;
an oxidation layer on the surface;
a charge generation layer disposed over the oxidation layer, the charge generation layer having a uniform first thickness along about two-thirds of a length of the elongated support element ranging from about 0.2 to about 0.5 μm and, along about one-third of a remainder of the length of a distal or proximate end of the elongated support element, the charge generation layer having a uniform second thickness greater than the first thickness and being distinct from the first thickness by a transition in thickness from a middle one-third of the length of the elongated support element; and
a charge transport layer disposed over the charge generation layer.
2. The photoconductive drum of claim 1 , further including a protective overcoat over the charge transport layer.
3. The photoconductive drum of claim 1 , wherein the second thickness is about 0.1 μm thicker than the first thickness.
4. The photoconductive drum of claim 1 , wherein the elongated support element is substantially cylindrical about a longitudinal axis thereof.
5. The photoconductive drum of claim 1 , wherein the charge generation layer tapers symmetrically from the second thickness to the first thickness at the transition in thickness.
6. The photoconductive drum of claim 1 , wherein the elongated support element is a 3003 aluminum alloy.
7. The photoconductive drum of claim 1 , wherein the elongated support element is hollow with an inner and outer diameter being in a range of about 20 to about 25 mm and having said length in a range of about 245 to about 255 mm.
8. The photoconductive drum of claim 1 , wherein the oxidation layer is about 3 to about 5 μm.
9. The photoconductive drum of claim 1 , wherein the charge transport layer is about 17 to about 19 μm.
10. The photoconductive drum of claim 1 , wherein an active ingredient of the charge generation layer is titanyl phthalocyanine.
11. A photoconductive drum, comprising:
a substantially cylindrical elongated support element having a length and being an aluminum alloy;
a charge generation layer disposed over the elongated support element, the charge generation layer having a uniform first thickness along about two-thirds of the length of the elongated support element ranging from about 0.2 to about 0.5 μm and, along about one-third of a remainder of said length of the elongated support element, the charge generation layer having a uniform second thickness greater than the first thickness by about 0.1 μm and being distinct from the first thickness by a transition in thickness from a middle one-third of the length of the elongated support element; and
a charge transport layer disposed over the charge generation layer.
12. The photoconductive drum of claim 11 , further including an oxidation layer on a surface of the elongated support element.
13. The photoconductive drum of claim 11 , wherein about 2 mm of the elongated support element is uncoated with the charge generation layer.
14. The photoconductive drum of claim 11 , wherein the elongated support element is hollow with an inner and outer diameter being in a range of about 20 to about 25 mm and having said length in a range of about 245 to about 255 mm.
15. The photoconductive drum of claim 11 , wherein the charge transport layer extends in thickness about the elongated support element in a range of about 17 to about 19 μm.
16. The photoconductive drum of claim 11 , wherein the charge generation layer is polyvinylbutyral.