Fixing device

摘要

A fixing device includes a rotatable fuser member, a rotatable pressure member, a heater, and a controller. The rotatable fuser member is subjected to heating. The rotatable pressure member is disposed opposite the fuser member. The pressure member presses against the fuser member to form a fixing nip therebetween, through which multiple recording media, each spaced apart from each other by an interval distance in a conveyance direction, are sequentially conveyed at a conveyance speed. The heater is disposed adjacent to the fuser member to heat the fuser member. The controller is operatively connected to the heater to control power supply to the heater through a series of on-off switching control cycles, each including an on-time during which the heater power supply is on, and an off-time during which the heater power supply is off, in synchronization with conveyance of the recording medium.

主权项

1. A fixing device comprising:
a rotatable fuser member subjected to heating; a rotatable pressure member disposed opposite the fuser member, the pressure member pressing against the fuser member to form a fixing nip therebetween, through which multiple recording media, each spaced apart from each other by an interval distance in a conveyance direction, are sequentially conveyed at a conveyance speed; a heater adjacent to the fuser member to heat the fuser member; and a controller operatively connected to the heater to control power supply to the heater through a series of on-off switching control cycles, each including an on-time during which the heater power supply is on, and an off-time during which the heater power supply is off, in synchronization with conveyance of the recording medium to satisfy the following equation:
T1+T2=C*X where “T1” is a length of media passage time during which each recording medium passes through the fixing nip, “T2” is a length of interval time between two successive recording media exiting and subsequently entering the fixing nip, “C” is a duration of the control cycle of the heater power supply, and “X” is a cycle count being a positive integer, wherein the controller corrects a duty ratio, being a ratio of the on-time relative to a sum of the on-time and the off-time, by adding a positive correction factor decreasing with an increasing number of control cycles performed to the duty ratio in a condition in which a temperature of the pressure member equals or exceeds a threshold temperature.