Claims
- 1. A fixing device, comprising:
- a fixing rotary member having an electrically conductive core member and an electrically insulative non-adhesive surface layer provided thereon;
- voltage applying means for applying a bias voltage having the same polarity as an unfixed toner image to said conductive core member; and
- a back-up member forming a nip with said fixing rotary member,
- wherein a recording material bearing an unfixed toner image is passed through the nip to fix the unfixed toner image on the recording material, and
- wherein said back-up member includes a low resistance elastic layer at a surface thereof or in the vicinity of the surface,
- wherein both ends of said non-adhesive surface layer extend outwardly over both ends of said low resistance elastic layer, and
- wherein, when the voltage applied to said rotary member is V(V), a difference AB (mm) in distance between the end of said non-adhesive surface layer and the corresponding end of said back-up member is indicated as the following equation:
- AB=V/300+.alpha.(mm)
- wherein .alpha. is a tolerance value and .alpha..ltoreq.1 mm.
- 2. A fixing device according to claim 1, wherein a volume resistivity value of said non-adhesive surface layer is not less than 10.sup.14 .OMEGA. cm.
- 3. A fixing device according to claim 1, wherein said non-adhesive surface layer is made of pure fluororesin.
- 4. A fixing device according to claim 1, wherein a volume resistivity value of said low resistant elastic layer is 10.sup.2 to 10.sup.5 .OMEGA. cm.
- 5. A fixing device according to claim 1, wherein said elastic layer is a surface rubber layer.
- 6. A fixing device according to claim 1, wherein said elastic layer of low electrical resistance is a rubber layer, and an electrically insulative surface resin layer is provided on said rubber layer.
- 7. A fixing device according to claim 1, wherein said distance AB is V/300 (mm).
- 8. A fixing device according to claim 1, further comprising electrical charge removing means for removing an electrical charge on said non-adhesive surface layer.
- 9. A fixing device according to claim 1, wherein the unfixed toner image contacts with said fixing rotary member, and the unfixed toner image receives electrostatic attractive force directed to said back-up member.
- 10. A fixing device according to claim 1, wherein said back-up member has an actual resistance of 10.sup.3 .OMEGA. to 10.sup.11 .OMEGA..
- 11. A fixing device according to claim 1, wherein said low resistance elastic layer is grounded via a rectifier element, said rectifier element being connected in a direction that electric charges having the polarity opposite to that of the unfixed toner can be shifted from the grounded side to said low resistance elastic layer.
- 12. A fixing device according to claim 1, wherein said back-up member includes an electrically conductive surface resin layer which is provided on said low resistant elastic layer.
- 13. A fixing device, comprising:
- a fixing rotary member having an electrically conductive core member and an electrically insulative non-adhesive surface layer provided thereon;
- voltage applying means for applying a bias voltage to said conductive core member ;and
- a back-up member forming a nip with said fixing rotary member,
- wherein a recording material bearing an unfixed toner image is pinched and conveyed through said nip to fix the unfixed toner image on the recording material, and
- said back-up member includes a low resistant elastic layer at a surface thereof or in the vicinity of the surface, wherein a volume resistivity value of said low resistant elastic layer is 10.sup.2 .OMEGA. to 10.sup.5 .OMEGA..multidot.cm.
- 14. A fixing device according to claim 13, wherein the volume resistivity value of said non-adhesive surface layer is not less than 10.sup.14 .OMEGA. cm.
- 15. A fixing device according to claim 13, wherein said non-adhesive surface layer is made of pure fluororesin.
- 16. A fixing device according to claim 13, wherein said bias voltage has the same polarity as the unfixed toner image.
- 17. A fixing device according to claim 16, wherein the unfixed toner image contacts with said fixing rotary member.
- 18. A fixing device according to claim 13, wherein said low resistant elastic layer is a surface rubber layer.
- 19. A fixing device according to claim 13, wherein said low resistant elastic layer is a rubber layer, and an electrically insulative surface resin layer is provided on said rubber layer.
- 20. A fixing device according to claim 13, wherein both ends of said non-adhesive surface layer extend outwardly over both ends of said low resistant elastic layer.
- 21. A fixing device according to claim 20, wherein when the voltage applied to said rotary member is V (V), a difference AB (mm) is a distance between an end of said non-adhesive surface layer and a corresponding end of said back-up member is indicated as the following equation:
- AB (mm)=V/300+.alpha. (mm),
- where .alpha. is a tolerance value and .alpha..ltoreq.1 mm.
- 22. A fixing device according to claim 21, wherein said distance AB is V/300 (mm).
- 23. A fixing device according to claim 13, further comprising electrical charge removing means for removing an electrical charge on said non-adhesive surface layer.
- 24. A fixing device according to claim 13, wherein said back-up member has an actual resistance of 10.sup.3 .OMEGA. to 10.sup.11 .OMEGA..
- 25. A fixing device according to claim 13, wherein said low resistance elastic layer is grounded.
- 26. A fixing according to claim 13, wherein said low resistance elastic layer is grounded via a rectifier element, said rectifier element being connected in a direction that electric charges having the polarity opposite to that of the unfixed toner can be shifted from the grounded side to said low resistance elastic layer.
- 27. A fixing device according to claim 13, wherein said fixing device is disposed downstream of a transfer portion to transfer a toner image onto the recording material by a charge in a convey direction of the recording member, and a length of the recording material is longer than a distance between the transfer portion and the fixing nip.
- 28. A fixing device according to claim 13, wherein a surface releasing layer is provided on said low resistance elastic layer.
- 29. A fixing device according to claim 28, wherein said surface releasing layer has a thickness of 60 .mu.m or less.
- 30. A fixing device according to claim 13, wherein said back-up member includes an electrically conductive surface resin layer which is provided on said low resistant layer.
Priority Claims (3)
Number |
Date |
Country |
Kind |
2-73293 |
Mar 1990 |
JPX |
|
2-272593 |
Oct 1990 |
JPX |
|
3-036172 |
Mar 1991 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/113,311 filed Aug. 30, 1993, which in turn is a continuation of application Ser. No. 07/674,944 filed Mar. 26, 1991, both now abandoned.
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Continuations (2)
|
Number |
Date |
Country |
Parent |
113311 |
Aug 1993 |
|
Parent |
674944 |
Mar 1991 |
|