Patent ID: 8886098

Claim:
An apparatus useful for printing, comprising: a belt including an inner surface and an outer surface; a first member including a first outer surface; a second member including a second outer surface, wherein the second outer surface is substantially cylindrical over a central major portion and includes a first flaring that flares outwardly with increasing diameter at each end; a plurality of identical guide rollers mounted to a frame for defining a path along which the belt is driven in a process direction, each of the plurality of guide rollers having a longitudinal axis about which it is mounted to rotate and a drive surface formed generally concentrically about the longitudinal axis, wherein each of the plurality of guide rollers has a drive surface that is substantially cylindrical over a central major portion and includes a second flaring that flares outwardly with increasing diameter at each end, the drive surface having a portion between two points thereon that extends along a line parallel to the rotational axis; and a nip formed by contact between the inner surface of the belt and the second outer surface and contact between the outer surface of the belt and the first outer surface; wherein a desired strained shape of the belt is defined by a percentage increase in a length of the belt at its edges as compared to a length of the belt at its center, the first flaring is selected such that a percentage increase in the diameter of the second member at each end as compared to the diameter of the second member at its central major portion is equal to the percentage increase that defines the desired strained shape, the second flaring is selected such that the plurality of guide rollers strain the belt to the desired; strained shape, the percentage increase in diameter of the second flaring is different than the percentage increase in diameter of the first flaring.