Patent ID: 9354567
Filing Date: 2016-05-31
CPC Classification: G03G

Claim Text:
1. A fixing device for fixing a toner image printed on a recording medium having a specific heat capacity, the fixing device comprising: a rotatable fuser member subjected to heating; a heater to heat the fuser member to a heating temperature; a rotatable pressure member disposed opposite the fuser member; the fuser member and the pressure member pressed against each other to form a fixing nip therebetween, through which the recording medium is conveyed with a first, printed surface thereof facing the fuser member and a second, non-printed surface thereof facing the pressure member, so as to fix the toner image in place under heat and pressure as the fuser and pressure members rotate together; a thermometer disposed adjacent to the pressure member to detect an operational temperature of the pressure member; a feedback controller operatively connected with the thermometer to control the heating temperature according to the detected operational temperature, so that the recording medium exhibits a substantially constant post-fixing temperature downstream from the fixing nip regardless of the heat capacity of the recording medium; and a memory configured to store a lookup table or mathematical formula, which associates a specific operational temperature of the pressure member with a heating temperature for maintaining the post-fixing temperature of the recording medium at a set temperature, the memory being connected to the feedback controller, wherein the temperature of the pressure member is detected by the thermometer during passage through the fixing nip for every type of a recording medium having any value of a heat capacity and a basis weight, and based on the temperature thus obtained, a setpoint temperature of the fuser member is determined, wherein the feedback controller adjusts the heating temperature based on an operational parameter with which the recording medium in use is processed through the fixing nip, wherein with regards to an adjustment of a slope of the setpoint temperature of the fuser roller relative to the detected temperature of the pressure roller, the temperature of the fuser roller is corrected by at least one operational parameter, wherein the operational parameter includes a composite parameter obtained by combining at least two of nip dwell time, basis weight, thermal conductivity, specific heat capacity, and moisture content of the recording medium in use, and wherein the composite parameter is obtained by dividing the thermal conductivity by the basis weight.