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US 6,807,386 B2Granted
Fixing device and image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsMotokazu Yasui, Hideo Furukawa, Masanao Ehara, Masaharu Furuya
Life of this patent
Estimating the term…
Abstract
A fixing device includes a fixing belt, a first heater, a second heater, a supporting roller, and a counter roller. During activation of the fixing device, a maximum power is supplied to the first heater, and only the first heater heats the fixing belt. When a temperature on the fixing belt reaches a first reference temperature, the fixing belt is driven rotationally, the power supplied to the first heater is dropped, and power is supplied also to the second heater. When the temperature on the fixing belt reaches a target temperature and the temperature on the counter roller reaches a second reference temperature, fixing operation is allowed to start.
Claims31
A fixing device comprising:
- a fixing belt which is driven rotationally;
- a counter member disposed opposite to the fixing belt;
- a first heater which heats the fixing belt;
- and
- a second heater which heats the counter member, wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium carrying a toner image to be fixed thereon is passed such that the toner image is directed to contact a surface of the fixing belt, in the presence of heat and pressure applied to toner in the toner image during passage thereof to fix the toner image on the recording medium,
- wherein a target temperature on the fixing belt during fixation is previously set, and first and second reference temperatures are previously set, the first and second reference temperatures being lower than the target temperature,
- a maximum allowable power is supplied to the first heater to heat the fixing belt when the temperature on the fixing belt is lower than the first reference temperature during activation of the fixing device,
- the fixing belt is driven rotationally, power supplied to the first heater is decreased, and power is also supplied to the second heater when the temperature on the fixing belt reaches the first reference temperature, and
- fixation is allowed to start at a point in time at which the temperature on the fixing belt reaches the target temperature and the temperature on the counter member reaches the second reference temperature.
6 more elements
A fixing device comprising:
- a driving roller;
- a plurality of belt supports including the driving roller;
- a first heater;
- an endless fixing belt wound around between the belt supports and heated by the first heater;
- a second heater;
- a counter member disposed opposite to one of the belt supports via the fixing belt and heated by the second heater;
- and
- a temperature detector which detects a surface temperature on the fixing belt,
- wherein when the surface temperature on the fixing belt is lower than a predetermined temperature during activation of the device, a first power is supplied to the first heater, and
- when the surface temperature on the fixing belt reaches the predetermined temperature, a second power is supplied to heat the second heater, at least the fixing belt is driven rotationally, and the power supplied to the first heater is dropped to an amount equal to an amount obtained by subtracting the second power from the first power.
7 more elements
A fixing device comprising:
- at least two belt supports;
- a fixing belt wound around between at least the two belt supports;
- a counter member disposed opposite to one of the belt supports via the fixing belt;
- a first heater which heats the fixing belt;
- a second heater which heats the counter member;
- a temperature detector which detects a temperature on the fixing belt, wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium is passed to fix an image on the recording medium;
- and
- a power controller which varies a ratio of power supplied to the second heater to power to the first heater based on the temperature detected by the temperature detector.
5 more elements
A fixing device comprising:
- at least two belt supports;
- a fixing belt wound around between at least the two belt supports;
- a counter member disposed opposite to one of the belt supports via the fixing belt;
- a first heater which heats the fixing belt;
- a second heater which heats the counter member, wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium is passed to fix an image on the recording medium;
- a time detector which detects a time of supplying power to at least one of the first and the second heaters;
- and
- a power controller which varies a ratio of power supplied to the second heater to power to the first heater based on the time detected by the time detector.
5 more elements
An image forming apparatus comprising:
- a fixing device including
- a fixing belt which is driven rotationally;
- a counter member disposed opposite to the fixing belt;
- a first heater which heats the fixing belt;
- and
- a second heater which heats the counter member,
- wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium carrying a toner image to be fixed thereon is passed such that the toner image is directed to contact a surface of the fixing belt, in the presence of heat and pressure applied to toner in the toner image during passage thereof to fix the toner image on the recording medium,
- wherein a target temperature on the fixing belt during fixation and first and second reference temperatures are previously set, first and second reference temperatures being lower than the target temperature,
- a maximum allowable power is supplied to the first heater to heat the fixing belt when the temperature on the fixing belt is lower than the first reference temperature during activation of the fixing device,
- the fixing belt is driven rotationally, power supplied to the first heater is decreased, and power is also supplied to the second heater when the temperature on the fixing belt reaches the first reference temperature, and
- fixation is allowed to start at a point in time at which the temperature on the fixing belt reaches the target temperature and the temperature on the counter member reaches the second reference temperature.
8 more elements
An image forming apparatus comprising:
- a fixing device including
- a driving roller;
- a plurality of belt supports including the driving roller;
- a first heater;
- an endless fixing belt wound around between the belt supports and heated by the first heater;
- a second heater;
- a counter member disposed opposite to one of the belt supports via the fixing belt and heated by the second heater;
- and
- a temperature detector which detects a surface temperature on the fixing belt,
- wherein when the surface temperature on the fixing belt is lower than a predetermined temperature during activation of the device, a first power is supplied to the first heater, and
- when the surface temperature on the fixing belt reaches the predetermined temperature, a second power is supplied to heat the second heater, at least the fixing belt is driven rotationally, and the power supplied to the first heater is dropped to an amount equal to an amount obtained by subtracting the second power from the first power.
8 more elements
An image forming apparatus comprising:
- a fixing device including
- at least two belt supports;
- a fixing belt wound around between at least the two belt supports;
- a counter member disposed opposite to one of the belt supports via the fixing belt;
- a first heater which heats the fixing belt;
- a second heater which heats the counter member;
- a temperature detector which detects a temperature on the fixing belt, wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium is passed to fix an image on the recording medium;
- and
- a power controller which varies a ratio of power supplied to the second heater to power to the first heater based on the temperature detected by the temperature detector.
6 more elements
An image forming apparatus comprising:
- a fixing device including
- at least two belt supports;
- a fixing belt wound around between at least the two belt supports;
- a counter member disposed opposite to one of the belt supports via the fixing belt;
- a first heater which heats the fixing belt;
- a second heater which heats the counter member,
- wherein the fixing belt and the counter member define a nip therebetween, through which a recording medium is passed to fix an image on the recording medium;
- a time detector which detects a time of supplying power to at least one of the first and the second heaters;
- and
- a power controller which varies a ratio of power supplied to the second heater to power to the first heater based on the time detected by the time detector.
7 more elements
Dependencies are inferred from the claim text.