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US 6,351,619 B1Granted
Image forming apparatus, belt type fixing device and heating control
AssigneeRicoh Company, Ltd.
InventorMasamichi Yamada
Life of this patent
Estimating the term…
Abstract
A belt type fixing device of the present invention includes an endless belt, a conveyor roller supporting the belt such that the belt is rotatable, a first heat source for heating the belt, a first temperature sensor, a press roller for pressing a recording medium against the belt, a hollow roller contacting the outer surface of the belt, a second heat source disposed in or adjoining the hollow roller and a second temperature sensor. The fixing device is capable of reducing a warm-up time and preventing the belt from being adhered to the hollow roller by toner and damaged.
Claims7
A belt type fixing device comprising:
- an endless belt;
- a conveyor roller supporting said belt such that said belt is rotatable;
- a first heat source for heating said belt;
- a press roller for pressing a recording medium against said belt;
- a hollow roller contacting an outer surface of said belt, wherein said hollow roller is rotatable in a same direction as said belt, as seen at a position where said hollow roller and said belt contact each other, at a peripheral speed equal to or higher than a peripheral speed of said belt;
- a second heat source disposed in or adjoining said hollow roller;
- a controller configured to control a driving of said fixing device and said hollow roller, wherein said fixing device and said hollow roller are not driven until a surface layer, included in said hollow roller, reaches at least a temperature higher than a softening point of toner;
- first temperature sensing means for sensing a temperature of a surface layer included in said hollow roller, wherein said second heat source is controlled on the basis of the temperature being sensed by said first temperature sensing means;
- and
- second temperature sensing means for sensing a temperature of a surface layer included in said belt, wherein said first heat source is so controlled as to cause the temperature being sensed by said second temperature sensing means to coincide with a first preselected temperature while said second heat source is so controlled as to cause the temperature being sensed by said first temperature sensing means to coincide with a second preselected temperature lower than or equal to said first preselected temperature.
7 more elements
A belt type fixing device comprising:
- an endless belt;
- a conveyor roller supporting said belt such that said belt is rotatable;
- first heat source for heating said belt;
- a press roller for pressing a recording medium against said belt;
- a hollow roller contacting an outer surface of said belt;
- a second heat source disposed in or adjoining said hollow roller;
- a controller configured to control a driving of said fixing device and said hollow roller, wherein said fixing device and said hollow roller are not driven until a surface layer, included in said hollow roller, reaches at least a temperature higher than a softening point of toner;
- first temperature sensing means for sensing a temperature of a surface layer included in said hollow roller, wherein said second heat source is controlled on the basis of the temperature being sensed by said first temperature sensing means;
- and
- second temperature sensing means for sensing a temperature of a surface layer included in said belt, wherein said first heat source is so controlled as to cause the temperature being sensed by said second temperature sensing means to coincide with a first preselected temperature while said second heat source is so controlled as to cause the temperature being sensed by said first temperature sensing means to coincide with a second preselected temperature lower than or equal to said first preselected temperature.
7 more elements
In an image forming apparatus including a belt type fixing device, said belt type fixing device comprising
- an endless belt;
- a conveyor roller supporting said belt such that said belt is rotatable;
- first heat source for heating said belt;
- a press roller for pressing a recording medium against said belt;
- hollow roller contacting an outer surface of said belt;
- second heat source disposed in or adjoining said hollow roller;
- a controller configured to control a driving of said fixing device and said hollow roller, wherein said fixing device and said hollow roller are not driven until a surface layer, included in said hollow roller, reaches at least a temperature higher than a softening point of toner;
- first temperature sensing means for sensing a temperature of a surface layer included in said hollow roller, wherein said second heat source is controlled on the basis of the temperature being sensed by said first temperature sensing means;
- and
- second temperature sensing means for sensing a temperature of a surface layer included in said belt, wherein said first heat source is so controlled as to cause the temperature being sensed by said second temperature sensing means to coincide with a first preselected temperature while said second heat source is so controlled as to cause the temperature being sensed by said first temperature sensing means to coincide with a second preselected temperature lower than or equal to said first preselected temperature.
7 more elements
Dependencies are inferred from the claim text.