Patent ID: 8047940

Claim:
A heat-resistant resin belt, which can be employed in a thermal fixing apparatus used to fix a toner image to a recording medium, the heat-resistant resin belt comprising: a heat-resistant resin sheet; a first cutting work part formed by cutting a front surface of one end of the heat-resistant resin sheet into an inclined shape in section; and a second cutting work part formed by cutting a rear surface of the other end into an inclined shape in section, wherein both of the inclined work parts are overlapped with each other and bonded with an adhesive to form a bonding part; and wherein an external shape displacement f(x) of the heat-resistant resin belt, measured via a flatness measuring apparatus, which scans the heat-resistant resin belt, satisfies a following formula ∫ 0 x ⁢  f ⁡ ( x ) - g ⁡ ( x )  ⁢ ⁢ ⅆ x ≤ XL 6800 , wherein “X” (mm) is a length of the heat-resistant resin belt in a width direction thereof; “L” (mm) is a perimeter of the heat-resistant resin belt; “x” is a length from a scan beginning point in a scanning direction parallel to each of the longitudinal axes of shafts used to stretch the heat-resistant belt or an edge of the heat-resistant belt; and “g(x)” represents an ideal external shape displacement of the heat-resistant resin belt, here, when g(x)=C (a constant profile), a special profile is set to g(x) so that a left side of the formula (1) takes a minimum value; whilst, when g(x)=a variable, another special profile or an ideal external shape displacement of the heat-resistant resin belt to be targeted by which neither wrinkling occurred in a test paper when the thus manufactured heat-resistant belt is built into an image forming apparatus and printing is performed using the heat-resistant belt or shaving of an inner surface of the heat-resistant belt is present, is set to g(x).