Original Publication Date: 1982-Aug-31
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
to permanently affix the toner powder image to the copy sheet. The fuser roller applies heat and pressure to the toner particles resulting in melting and adherence of the toner particles to the copy paper. Generally, the fuser roller is coated with a compliant material such as silicone rubber. Pressure is applied to the copy sheet via springs, cams, pneumatics, hydraulics, etc. The tolerances involved in setting the nip, roll runout, material durometer consistency, uniformity and thickness uniformity, sleeve covering thickness uniformity, etc. usually result in varying nips under dynamic conditions. It also results in varying circumferential surface speeds along the axial length of the roll. This produces a non-uniform class of fusing with the paper being subjected to stresses resulting in localized deformations producing wrinkling, i.e, creasing of the paper. Moreover, a roll coated with a compliant material exhibits an apparent hardness which is considerably lower at the ends than in the center. This produces another localized circumferential surface speed variation. Depending on the roll length, copy sheet length and location, this can result in wrinkles. In order to solve the foregoing problems, it has been found that a fuser roll, as shown in the drawing, comprising an outer compliant sleeve 10 interfit over region 12 of rigid roll 14 results in a significant improvement in system performance. As is shown, shaft 16 -is secured to roll 14. A portion of roll 14 having a diameter less than region 12 extends outwardly therefrom. Sleeve 10 and roll 14 are symmetrical about an axis substantially normal. to the longitudinal axis of shaft 16. A-roller of this type insures the desired fixing of the toner powder image to the copy sheet while minimizing or eliminating wrinkle problems.