Patent ID: 9329538
Filing Date: 2016-05-03
CPC Classification: G03G

Claim Text:
1. A fixing device configured to fix a toner image on a sheet, the fixing device comprising: a heat rotor equipped with a heat source; a pressure rotor pressed against the heat rotor to form a fixing nip and expandable by heat given from the heat rotor; a drive section configured to drive the pressure rotor into rotation; a control section configured to control the drive section and thus control a rotational speed of the pressure rotor; and a heat quantity detecting section configured to determine a quantity of heat given from the heat rotor to the pressure rotor, wherein the control section is configured to perform a first rotation control so that after the heat quantity detecting section detects that a predetermined specified quantity of heat has been given from the heat rotor to the pressure rotor since a reference time point when the fixing device has transitioned from an outage state to an operating state, the control section allows the pressure rotor to rotate at a predetermined first rotational speed and that before the heat quantity detecting section detects that the specified quantity of heat has been given to the pressure rotor, the control section allows the pressure rotor to rotate at a second rotational speed obtained by correcting the first rotational speed according to the quantity of heat determined by the heat quantity detecting section, the fixing device further comprises a storage section configured to store correction values for use in obtaining the second rotational speed, the control section is configured to perform the first rotation control based on the correction value in the storage section, the correction value is a correction value for making the second rotational speed greater than the first rotational speed, and a rate of speed increase when the quantity of heat is a first quantity of heat is higher than a rate of speed increase when the quantity of heat is a second quantity of heat larger than the first quantity of heat.