Patent ID: 6333490
Filing Date: 2001-12-25
Classification: G03G

Abstract:
An apparatus for fixing a toner image to a sheet, comprising:a fixing roller;a pressing roller urged toward said fixing roller for pressing a sheet with an unfixed toner image carried on a surface thereof against said fixing roller to fix the unfixed toner image to said sheet when said sheet passes in one direction through a rolling contact region between said fixing roller and said pressing roller;a heating roller disposed on one side of said fixing roller opposite to said pressing roller;a first heating source disposed in said heating roller for heating said heating roller;an endless heat transfer belt trained around said heating roller and said fixing roller for transferring heat from said first heating source to heat the unfixed toner image on said sheet when said sheet passes through said rolling contact region; anda second heating source disposed in said pressing roller for heating said pressing roller; anda control device for energizing said first heating source and said second heating source when the apparatus is in a standby mode, and energizing said first heating source when the apparatus is in a sheet feed mode, and energizing said second heating source when the apparatus is in the sheet feed mode only if said sheet is of a size larger than a predetermined size, wherein said control device includes a first detecting device for detecting a surface temperature of said heating roller, a second detecting device for detecting a surface temperature of said fixing roller, and a third detecting device for detecting a surface temperature of said pressing roller;said control device further includes a controller for controlling said first heating source based on the surface temperature detected by said first detecting device and controlling said second heating source based on the surface temperature detected by said third detecting device when the apparatus is in said standby mode, and controlling said first heating source based on the surface temperature detecting by said second detecting device when the apparatus is in said sheet feed mode.