Fixing roll in a copying machine

Claim 1

Heat and pressure fuser apparatus for fixing toner images to copy substrates passing through a nip formed between two pressure engaged roll structures, at least one of the roll structures being heated and contacting the toner images as the substrates pass through said nip, the improvement comprising: said at least one of said roll structures being characterized by a cylindrical configuration having an outer circumferential wall which is relatively thin thereby having a relatively small heat capacity for minimizing the time required to elevate it to the fusing temperature, said at least one of said roll structures further characterized by reinforcing means associated with said circumferential wall for rendering said relatively thin wall sufficiently rigid to withstand the pressures to which it is subjected during fusing, said reinforcing means comprising a plurality of reinforcing ribs extending along the length of said wall and radially inward toward the center of said at least one roll structure, said at least one of said roll structures being further characterized by the provision of a plurality of plate members disposed transversely relative to the longitudinal axis of said at least one of said roll structures and provided with slots for receiving said reinforcing ribs, said plate members cooperating with said reinforcing ribs to render said circumferential wall rigid.