Fixing apparatus and image forming apparatus

• US 20040033084A1
• Filed: 06/18/2003
• Published: 02/19/2004
• Est. Priority Date: 06/21/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Akizuki, Tomoo, Tsuchiya, Toshikazu, Umezawa, Masao, Ando, Atsutoshi, Saito, Hisahiro
• Granted Patent: US 7,136,601 B2
• Time in Patent Office: Days
• US Class Current: 399/69
• CPC Class Codes: G03G 15/2046 specially for the influence of heat loss, e.g. due to the contact with the copy material or other roller

Abstract

In a fixing apparatus using a fixing belt having an elastic layer as a fixing member and an image forming apparatus mounting such a fixing apparatus thereto, before a temperature detecting unit detects temperature change caused upon recording material rushing, an electric power required to be applied to a heating element to heat the heating element is corrected to a predetermined electric power, and, when the fixing apparatus is started-up upon starting of print, at a predetermined timing, the electric power required to be applied to the heating element to heat the heating element is corrected to the predetermined electric power and a value of the predetermined electric power is substantially the same as an electric power value required for reaching the fixing apparatus to the predetermined power. The value of the predetermined power is determined in accordance with heat capacity of the recording material or a heat accumulating degree of the fixing apparatus on demand.

Claims

1. A fixing apparatus comprising:

at least,

a heating element;

an electric power supplying portion for supplying an electric power to said heating element;

at least one or more temperature detecting means;

a first rotary member shifted together with a recording material; and

a second rotary member for cooperating with the recording material to define an abutment portion therebetween;

wherein

a temperature of said first rotary member is controlled by performing feedback control of the electric power supplied from said electric power supplying portion to said heating element on the basis of a temperature detected by said temperature detecting means and the recording material bearing an image is nipped and conveyed at said abutment portion thereby to heat the recording material; and

further wherein

before said temperature detecting means detect temperature change caused when the recording material rushes into said abutment portion, an electric power supplied to said heating element and required for heating said heating element is corrected to a predetermined electric power.

2. A fixing apparatus according to claim 1, wherein a position where temperature detection of said temperature detecting means is performed is different from a heating area of said heating element.

3. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is substantially the same as an electric power value required after the recording material rushes into said fixing apparatus.

4. A fixing apparatus according to claim 1, wherein, during the applying of the predetermined electric power, the feedback control is not performed.

5. A fixing apparatus according to claim 1, wherein output of a value of the predetermined electric power is achieved by changing a target temperature of said temperature detecting means.

6. A fixing apparatus according to claim 1, wherein, when said temperature detecting means are used as first temperature detecting means, second temperature detecting means are further provided other than said first temperature detecting means, and further wherein a position where temperature detection of said second temperature detecting means is performed is a position nearer a heating area of said heating element than said first temperature detecting means or within said heating area and, output of a value of the predetermined electric power is achieved by changing a target temperature of said second temperature detecting means.

7. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is determined from a heat accumulating degree of said fixing apparatus.

8. A fixing apparatus according to claim 7, wherein, when said temperature detecting means are used as first temperature detecting means, second temperature detecting means are further provided other than said first temperature detecting means, and further wherein a position where temperature detection of said second temperature detecting means is performed is a position nearer a heating area of said heating element than said first temperature detecting means or within said heating area and, before said fixing apparatus is started-up upon starting of an image forming operation, a value of the predetermined electric power is determined from a detection temperature of said second temperature detecting means.

9. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is determined from a print sheet number of said fixing apparatus.

10. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is determined from heat capacity of the recording material.

11. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is determined from a basis weight of the recording material.

12. A fixing apparatus according to claim 10, wherein a value of the predetermined electric power is determined from a paper mode to which the recording material belongs.

13. A fixing apparatus according to claim 10, wherein a value of the predetermined electric power is determined from a moisture absorbing degree of the recording material.

14. A fixing apparatus according to claim 1, wherein a value of the predetermined electric power is determined from good or bad of heat transfer characteristics from said fixing apparatus to the recording material.

15. A fixing apparatus according to claim 14, wherein a value of the predetermined electric power is determined in consideration of heat transfer characteristics from said fixing apparatus in a case where the recording material is a rough paper.

16. A fixing apparatus according to claim 14, wherein a value of the predetermined electric power is determined in consideration of heat transfer characteristics from said fixing apparatus in a case where the recording material is a film.

25. A fixing apparatus according to claim 1, wherein heat capacity of said first rotary member is from 4.2×

10<sup>−

2</sup> J/cm²·

°

C. to 4.2 J/cm²·

°

C.

26. A fixing apparatus according to claim 1, wherein heat capacity of said first rotary member is from 8.82×

10<sup>−

2</sup> J/cm²·

°

C. to 18.9×

10<sup>−

2</sup> J/cm²·

°

C.

27. A fixing apparatus according to claim 1, wherein a fixing belt constituted by providing an elastic layer on a belt-shaped member is used as said first rotary member.

28. A fixing apparatus according to claim 27, wherein a base material of said fixing belt is heat-resistive resin.

29. A fixing apparatus according to claim 27, wherein a base material of said fixing belt is metal.

30. A fixing apparatus according to claim 27, wherein a mold releasing layer is provided as an outermost surface layer of said fixing belt.

31. A fixing apparatus according to claim 1, wherein a line-shaped heating element is used as said heating element.

32. A fixing apparatus according to claim 1, wherein a ceramic heater constituted by forming a resistive heating element on a ceramic substrate is used as said heating element.

33. A fixing apparatus according to claim 1, wherein a heating element holding member holding said heating element is made of resin material.

34. A fixing apparatus according to claim 33, wherein said heating element holding member is made of liquid crystal polymer.

35. An image forming apparatus wherein it mounts a fixing apparatus according to claim 1 thereon.

36. An image forming apparatus according to claim 35, wherein said image forming apparatus is a color image forming apparatus for forming a color image by superimposing plural color toner images.

17. A fixing apparatus comprising:

at least,

a heating element;

an electric power supplying portion for supplying an electric power to said heating element;

at least one or more temperature detecting means;

a first rotary member shifted together with a recording material; and

a second rotary member for cooperating with the recording material to define an abutment portion therebetween;

wherein

a temperature of said first rotary member is controlled by performing feedback control of the electric power supplied from said electric power supplying portion to said heating element on the basis of a temperature detected by said temperature detecting means and the recording material bearing an image is nipped and conveyed at said abutment portion thereby to heat the recording material; and

further wherein

there is provided a period during which the feedback control is inhibited when said fixing apparatus is started-up upon starting of print;

in the period, two or more stage electric power levels including a first electric power level for quickly starting-up the temperature of said fixing apparatus and a second electric power level for stabilizing the temperature of said fixing apparatus are used and, thereafter, the feedback control is restored.

18. A fixing apparatus according to claim 17, wherein a position where temperature detection of said temperature detecting means is performed is different from a heating area of said heating element.

19. A fixing apparatus according to claim 17, wherein output of a value of the predetermined electric power is achieved by changing a target temperature of said temperature detecting means.

20. A fixing apparatus according to claim 17, wherein, when said temperature detecting means are used as first temperature detecting means, second temperature detecting means are further provided other than said first temperature detecting means, and further wherein a position where temperature detection of said second temperature detecting means is performed is a position nearer a heating area of said heating element than said first temperature detecting means or within said heating area and, output of a value of the predetermined electric power is achieved by changing a target temperature of said second temperature detecting means.

21. A fixing apparatus according to claim 17, wherein a value of the electric power level on and after the second electric power level is determined from a heat accumulating degree of said fixing apparatus.

22. A fixing apparatus according to claim 21, wherein, when said temperature detecting means are used as first temperature detecting means, second temperature detecting means are further provided other than said first temperature detecting means, and further wherein a position where temperature detection of said second temperature detecting means is performed is a position nearer a heating area of said heating element than said first temperature detecting means or within said heating area and, before said fixing apparatus is started-up upon starting of an image forming operation, a value of the electric power level on and after the second electric power level is determined from a detection temperature of said second temperature detecting means.

23. A fixing apparatus according to claim 21, wherein a value of the electric power level on and after the second electric power level is determined from a print sheet number of said fixing apparatus.

24. A fixing apparatus according to claim 21, wherein third temperature detecting means are further provided other than said first temperature detecting means and said second temperature detecting means, and further wherein a position where temperature detection of said third temperature detecting means is performed is within a heating area of said heating element or at a constructional part of said fixing apparatus other than said first rotary member and, a value of the electric power level on and after the second electric power level is determined from a detection temperature of said third temperature detecting means.