Heated rollers and pressure roller - have pressure between them released whenever they are not fixing toner image

摘要

The soft-surfaced pressure roller is pressed vertically against a hard, heated roller - or vertically between two hard, heated rollers - when fixing is in progress. The present arrangement reduces this pressure while leaving the rollers in light contact and rotating at all other times. The driving gear of the lowest of the rollers is mounted on a pivoted frame on which it can drop down from the other rollers. It is raised when required on a pair of gear wheels mounted on a pivoted arm. When the pressure is required, an electrically operated clutch first holds the lowest of the auxiliary wheels on its axle - on which, till then, it had been free to turn. The drive on the raising wheel, which is in mesh with this lowest wheel, now turns the pivoted arm, raising the roller's driving gear on its pivoted frame.