Patent ID: 8200136

Claim:
An image transfer roller (ITR) for the transfer of an image from a first substrate to a second substrate comprising: a shaft, the shaft including a first longitudinal end and a second longitudinal end; and an elastomer material covering all or a portion of the shaft, the outer surface of the elastomer material adapted to have a substantially quadratic crown profile, wherein the image transfer roller is operatively associated with generating a uniform image transfer electrical field across a nip for the transfer of an image from the first substrate to the second substrate, the nip associated with the longitudinal engagement of the elastomer material with one of the first and second substrates by the application of a first force to the first longitudinal end and a second force to the second longitudinal end, the first and second forces substantially orthogonal to the nip, and the first and second forces properly balanced relative to the other end to insure that the contact pressure profile in the longitudinal direction is symmetrical about the center of the elastomer material, and wherein D max represents the maximum diameter of the ITR determined at the outer surface of the elastomer material, the outer surface of the elastomer material is adapted to have a trapezoidal profile, the trapezoidal profile including a crown of amplitude C, a crown of longitudinal width L 1 , a first ramp extending from a first longitudinal end of the elastomer material to the crown and extending a longitudinal width of L 0 from the first longitudinal end of the elastomer material to the crown, a second ramp extending from a second longitudinal end of the elastomer material to the crown and extending a longitudinal width of L 0 from the second longitudinal end of the elastomer material to the crown, L representing the sum of the first ramp longitudinal width L 0 , the second ramp longitudinal width L 0 , and the longitudinal width L 1 of the crown, where L 0 /L equals 0.33.