Patent Number: 6,333,490

Title: Toner image fixing apparatus capable of keeping constant fixing rollertemperature

Abstract: A toner image fixing apparatus has a fixing roller, a pressing roller, anda heating roller. The pressing roller is normally urged toward the fixingroller for pressing a sheet with an unfixed toner image carried on asurface thereof against the fixing roller to fix the unfixed toner imageto the sheet when the sheet passes in one direction through a rollingcontact region between the fixing roller and the pressing roller. Theheating roller is disposed on one side of the fixing roller opposite tothe pressing roller. A first heat source is disposed in the heating rollerfor heating the heating roller, and a second heat source is disposed inthe pressing roller for heating the pressing roller. An endless heattransfer belt is trained around the heating roller and the fixing rollerfor transferring heat from the first heat source to heat the unfixed tonerimage on the sheet when the sheet passes through the rolling contactregion. When the apparatus is in a standby mode, a controller energizesthe first heat source and the second heat source. When the apparatus is inthe sheet feed mode, the controller energizes the first heat source, andalso energizes the second heat source only if the sheet is of a sizelarger than a predetermined size.

Inventors: Higashi; Yuichiro (Tokyo, JP), Hamada; Yasuhide (Tokyo, JP)


International Classification: G03G 15/20 (20060101); H05B 001/00 ()

Expiration Date: 12/25/2014