Apparatus for fixing toner images

Claim 2

Apparatus for fixing an image of fusible toner particles on flexible sheet material, comprising upright frames spaced apart at opposite side of the apparatus and defining a fixing zone therebetween, means for feeding said material with said image thereon into said zone at a substantially constant speed, two pressure rollers having coengaging smooth rigid peripheral surfaces pressed and rotated together, one over and upon the other, for engaging and advancing said material therebetween as said material passes said zone, means for rotating said rollers at a peripheral speed equal to said feeding speed, and means for constantly pressing each end of the upper of said rollers against the adjacent end of the lower of them under a selected force of between about 20 and about 3400 pounds per inch of length of the nip between said roller surfaces, said force being sufficiently great to join the toner particles superficially to one another and to the surface structure of said material by pressure as said material is advanced between said surfaces, each of said rollers having on its ends journals rotatable in respective surrounding anti-friction bearing units seated in respective recesses in said frames, each said bearing unit of the upper roller having a non-rotary outer bearing race that is free of constraint in downward direction otherwise than by the coengaging rigid peripheral surfaces of said rollers, a rigid pressure distributing block extending transversely over and seated on each said outer bearing race, each said block being displaceable vertically in a recess in one of said frames and having in each of its opposite end portions an upwardly open pocket containing a confined body of elastomeric material, a pressure member bearing downward upon each said elastomeric body, and adjustably settable means mounted in upper portions of said frames for holding each said pressure member pressed under a selected force against the related elastomeric body.

Claim 3

Apparatus for fixing an image of fusible toner particles on flexible sheet material, comprising walls defining a fixing zone therebetween, means for feeding said material with said image thereon into said zone at a substantially constant speed, two pressure rollers having coengaging smooth rigid peripheral surfaces pressed and rotated together for engaging and advancing said material therebetween as said material passes through said zone, means for rotating said rollers at a peripheral speed equal to said feeding speed, and means for constantly pressing each end of one of said rollers against the adjacent end of the other of them under a selected force of between about 20 and about 3400 pounds per inch of length of the nip between said roller surfaces, said force being sufficiently great to join the toner particles superficially to one another and to the surface structure of said material by pressure as said material is advanced between said surfaces, said walls including upright frames spaced apart at opposite sides of the apparatus, said feeding means comprising two feed rollers having coengaging smooth rigid peripheral surfaces for engaging and advancing said material therebetween, each set of said two rollers having one roller thereof disposed over and constantly pressing downwardly upon the other roller thereof, each of the said rollers having on its ends journals rotatable in respective surrounding anti-friction bearing units seated in respective recesses in said frames, each said bearing unit of the upper roller of each said set having a non-rotary outer bearing race that is free of constraint in downward direction otherwise than by the coengaging rigid peripheral surfaces of the roller set, a rigid pressure distributing block extending transversely over and seated on each said outer bearing race, each said block being displaceable vertically in a recess in one of said frames and having in each of its opposite end portions an upwardly open pocket containing a confined body of elastomeric material, a pressure member bearing downward upon each said elastomeric body, and adjustably settable means for holding each said pressure member pressed under a selected force against the related elastomeric body, said settable means being mounted in upper portions of said frames.

Claim 4

Apparatus for fixing an image of fusible toner particles on flexible sheet material, comprising walls defining a fixing zone therebetween, means for feeding said material with said image thereon into said zone at a substantially constant speed, two pressure rollers having coengaging smooth rigid peripheral surfaces pressed and rotated together for engaging and advancing said material therebetween as said material passes through said zone, means for rotating said rollers at a peripheral speed equal to said feeding speed, and means for constantly pressing each end of one of said rollers against the adjacent end of the other of them under a selected force of between about 20 and about 3400 pounds per inch of length of the nip between said roller surfaces, said force being sufficiently great to join the toner particles superficially to one another and to the surface structure of said material by pressure as said material is advanced between said surfaces, said walls including upright frames spaced apart at opposite sides of the apparatus, said feeding means comprising two feed rollers having coengaging smooth rigid peripheral surfaces for engaging and advancing said material therebetween, each set of said two rollers having one roller thereof disposed over and constantly pressing downwardly upon the other roller thereof, each of the said rollers having on its ends journals rotatable in respective surrounding anti-friction bearing units seated in respective recesses in said frames, each said bearing unit of the upper roller of each said set having a non-rotary outer bearing race that is free of constraint in downward direction otherwise than by the coengaging rigid peripheral surfaces of the roller set, a rigid pressure distributing block extending transversely over and seated on each said outer bearing race, each said block being displaceable vertically in a recess in one of said frames and having in each of its opposite end portions an upwardly open pocket containing a confined body of elastomeric material, a pressure member bearing downward upon each said elastomeric body, and adjustably settable means for holding each said pressure member pressed under a selected force against the related elastomeric body, said settable means being mounted in upper portions of said frames.

Claim 5

Apparatus according to claim 2, and drive transmission means interconnecting the lower of said feed rollers and the lower of said pressure rollers for rotating said rollers at a constant peripheral speed.

Claim 6

Apparatus according to claim 2, the peripheral surface of each of said rollers being a polished hardened steel surface.

Claim 7

Apparatus according to claim 2, said walls further including a substantially horizontal guide plate over which said material slides image-side-up between said feed rollers and said pressure rollers and a roof partition spaced above said guide plate, and heating means comprising a radiant heating device in the space between said plate and said partition, said roof partition having a heat reflective lower surface that reflects radiation incident thereto back toward said plate.