Claims
- 1. 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; and a second heating source disposed in said pressing roller for heating said pressing roller; and a 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.
- 2. The apparatus according to claim 1, further comprising a decision device for deciding whether the apparatus is in said standby mode or said sheet feed mode, said decision device including a determining device for determining that the apparatus is in said sheet feed mode when a sheet feed command is supplied, and that the apparatus is in said standby mode when a sheet feed command is not supplied.
- 3. An apparatus for fixing a toner image to a sheet, comprising:a fixing roller; a pressing roller normally 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; and a second heating source disposed in said pressing roller for heating said pressing roller; a decision device for determining the size of said sheet; and a 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, energizing said second heating source when the apparatus is in the sheet feed mode if said sheet is of a size larger than a predetermined size as determined by said decision device, and de-energizing said second heating source when the apparatus is in the sheet feed mode if said sheet is of a size smaller than said predetermined size as determined by said decision device, 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.
- 4. The apparatus according to claim 3, further comprising a decision device for deciding whether the apparatus is in said standby mode or said sheet feed mode, said decision device including a determining device for determining that the apparatus is in said sheet feed mode when a sheet feed command is supplied, and that the apparatus is in said standby mode when a sheet feed command is not supplied.
- 5. An apparatus according to claim 1, wherein said first heating source comprising a first heater for heating said heating roller when the sheet is of a size larger than a predetermined size and a second heater for heating said heating roller when the sheet is of a size smaller than said predetermined size.
- 6. The apparatus according to claim 5, wherein said first heater and said second heater include halogen lamps, respectively.
- 7. The apparatus according to claim 5, wherein said second heating source includes a halogen lamp.
- 8. The apparatus according to claim 5, further comprising a control device for energizing said first heater 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 such that said first heater is energized if said sheet is of the size larger than said predetermined size, and said second header is energized if said sheet is of the size smaller than said predetermined size.
- 9. The apparatus according to claim 8, wherein said control device includes a heater driver for energizing only said first heater if said sheet is of the size larger than said predetermined size and energizing only said second heater if said sheet is of the size smaller than said predetermined size.
- 10. The apparatus according to claim 5, further comprising a decision device for determining the size of said sheet, said control device including a heater driver for energizing said first heater when the apparatus is in said sheet feed mode if said sheet is of the size larger than said predetermined size as determined by said decision device, and energizing said second heater when the apparatus is in said sheet feed mode if said sheet is of the size smaller than said predetermined size as determined by said decision device.
- 11. A method of fixing a toner image to a sheet, comprising utilizing an apparatus havinga fixing roller having a resilient outer layer, a pressing roller having an outer layer with hardness higher than that of said outer layer of said fixing roller, said pressing roller normally 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, said first heating source including a first heater for heating said heating roller when the sheet is of a size larger than a predetermined size and a second heater for heating said heating roller when the sheet is of a size smaller than said predetermined size, 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, and a second heating source disposed in said pressing roller for heating said pressing roller; deciding whether said apparatus is in a sheet feed mode or not; determining the size of said sheet if said apparatus is in the sheet feed mode; energizing said first heater of the first heating source and energizing said second heating source when said first heater of the first heating source is energized, if the size of said sheet is larger than a predetermined size; and energizing said second heater of the first heating source if the size of said sheet is smaller than said predetermined size.
- 12. The method according to claim 11, further comprising a step of de-energizing said second heating source when said second heater of the first heating source is energized.
- 13. An apparatus according to claim 3, wherein said first heating source comprising a first heater for heating said heating roller when the sheet is of a size larger than a predetermined size and a second heater for heating said heating roller when the sheet is of a size smaller than said predetermined size.
- 14. The apparatus according to claim 13, wherein said first heater and said second heater include halogen lamps, respectively.
- 15. The apparatus according to claim 13, wherein said second heating source includes a halogen lamp.
- 16. The apparatus according to claim 13, further comprising a control device for energizing said first heater 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 such that said first heater is energized if said sheet is of the size larger than said predetermined size, and said second heater is energized if said sheet is of the size smaller than said predetermined size.
- 17. The apparatus according to claim 16, wherein said control device includes a heater driver for energizing only said first heater if said sheet is of the size larger than said predetermined size and energizing only said second heater if said sheet is of the size smaller than said predetermined size.
- 18. The apparatus according to claim 13, further comprising a decision device for determining the size of said sheet, said control device including a heater driver for energizing said first heater when the apparatus is in said sheet feed mode if said sheet is of the size larger than said predetermined size as determined by said decision device, and energizing said second heater when the apparatus is in said sheet feed mode if said sheet is the size smaller than said predetermined size as determined by said decision device.
Priority Claims (3)
Number |
Date |
Country |
Kind |
10-165849 |
Jun 1998 |
JP |
|
10-165850 |
Jun 1998 |
JP |
|
10-165851 |
Jun 1998 |
JP |
|
Parent Case Info
This application is a Continuation of application Ser. No. 09/266,017, filed Mar. 11, 1999 which is now U.S. Pat. No. 6,181,891, issued Jan. 30, 2001.
US Referenced Citations (8)
Foreign Referenced Citations (3)
Number |
Date |
Country |
5-27620 |
Feb 1993 |
JP |
5-80666 |
Apr 1993 |
JP |
7-319321 |
Dec 1995 |
JP |
Continuations (1)
|
Number |
Date |
Country |
Parent |
09/266017 |
Mar 1999 |
US |
Child |
09/660075 |
|
US |