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US 10,254,676 B2Granted
Charge roller for electrographic printer
AssigneeHewlett-Packard Development Company, L.P.
InventorsSeongsik Chang, Thomas Anthony, Michael H. Lee, Omer Gila, Anthony William McLennan
Life of this patent
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Abstract
A charge roller includes a body having a metal external surface and an inorganic outer resistive coating.
Claims15
An electrophotographic printing system comprising:
- a charging unit including a charge roller in charge-transferring relation to charge an imaging surface prior to formation of an electrostatic latent image on the imaging surface, the charge roller comprising a body having a metal external surface and an outer resistive inorganic, non-polymeric layer, wherein the outer resistive inorganic, non-polymeric layer is made solely from a semiconductor material chosen from silicon carbide, silicon, and hydrogenated silicon.
A charge roller in charge-transferring relation to an imaging surface of a liquid electrophotographic printing system, the charge roller comprising:
- a body having a metal external surface and an overlying resistive coating made of an inorganic, non-polymeric material, wherein a resistivity factor of the overlying resistive coating is expressed as ρ·εr, wherein εr is a dielectric constant, wherein p is resistivity, wherein t is a thickness of the resistive coating, and wherein t/εr>5 micrometers.
An electrophotographic printing system comprising:
- a charging unit including a charge roller in charge-transferring relation to an imaging surface and including a body having a metal external surface and an outer inorganic resistive layer,
- wherein the outer inorganic resistive layer has a resistivity factor greater than 103 Ohm-cm and less than about 109 Ohm-cm, and
- wherein the resistivity factor is expressed as ρ·εr, wherein εr is a dielectric constant, wherein ρ is resistivity, wherein t is a thickness of the resistive coating, and wherein t/εr>5 micrometers.
Dependencies are inferred from the claim text.