FIXING DEVICE AND IMAGE FORMING APPARATUS

摘要

A fixing device includes a cylindrical heat roller, a heating element, a pressure roller, and an auxiliary roller. The heating element is provided inside the heat roller and configured to apply heat to the heat roller. The pressure roller is configured to be pressed against the heat roller to form, with the heat roller, a nip area where a recording paper sheet is to be nipped. The auxiliary roller is provided inside the heat roller and configured to be pressed toward the pressure roller with a peripheral wall of the heat roller in between. An outer peripheral surface of the auxiliary roller pressed against an inner peripheral surface of the heat roller is formed into an inverted crown shape so that an outside diameter of the auxiliary roller gradually decreases from both axial ends of the auxiliary roller toward an axial center thereof.

主权项

1. A fixing device comprising:
a heat roller having a cylindrical shape; a heating element provided inside the heat roller and configured to apply heat to the heat roller; a pressure roller configured to be pressed against the heat roller to form, with the heat roller, a nip area where a recording paper sheet is to be nipped; and an auxiliary roller provided inside the heat roller and configured to be pressed toward the pressure roller with a peripheral wall of the heat roller in between, wherein an outer peripheral surface of the auxiliary roller pressed against an inner peripheral surface of the heat roller is formed into an inverted crown shape so that an outside diameter of the auxiliary roller gradually decreases from both axial ends of the auxiliary roller toward an axial center thereof.