Claims
- 1. A fixing unit that fixes a developing material deposited on a recording medium by heating and pressing the recording medium, comprising:
two heating members that apply heat to the recording medium; and two temperature-sensitive shut-off devices each of which is connected in series with a corresponding one of the two heating members;
wherein each of the two temperature-sensitive shut-off devices includes a first heat-sensitive shut-off element and a second heat-sensitive shut--off element, the first heat-sensitive shut-off element shutting off electric power to the corresponding one of the two heating members when a temperature of a surface of the corresponding one of the two heating members exceeds a certain value, the second heat-sensitive shut-off element shutting off electric power to the corresponding one of the two heating members when a temperature of a surface of the second one of the two heating members exceeds a certain value.
- 2. The fixing unit according to claim 1, wherein the two heating members and the two temperature-sensitive shut-off devices form two series connections,
wherein each of the two series connections is a series connection of one of the two heating members and one of the two temperature-sensitive shut-off devices, the two series connections being connected in parallel with an electric power source.
- 3. The fixing unit according to claim 1, wherein the temperature-sensitive shut-off devices are overtemperature thermostats.
- 4. The fixing unit according to claim 1, wherein the temperature-sensitive shut-off devices are thermal fuses.
- 5. A fixing unit that fixes a developing material deposited on a recording medium by heating and pressing the recording medium, comprising: and
a first number of heating members that apply heat to the recording medium; a second number of temperature-sensitive shut-off devices in series with each one of the first number of heating members;
wherein each of the first number of heating members receives electric power through a series connection of the second number of switches, the second number of temperature-sensitive shut-off devices operating in such a way that each of the first number of heating members receives electric power through the series connection of the second number of temperature-sensitive shut-off devices, each of the second number of temperature-sensitive shut-off devices receiving heat from a surface of a corresponding one of the first number of heating members to turn off the electric power in response to a temperature of the surface.
- 6. The fixing unit according to claim 5, wherein the first number of heating members include two heating members and the second number of temperature-sensitive shut-off devices include two temperature-sensitive shut-off devices.
- 7. The fixing unit according to claim 6, wherein the two heating members and the two temperature-sensitive shut-off devices form two series connections,
wherein each of the two series connections is a series connection of one of the two heating members and the two temperature-sensitive shut-off device, the two series connections being connected in parallel with an electric power source.
- 8. The fixing unit according to claim 5, wherein the temperature-sensitive shut-off devices are overtemperature thermostats.
- 9. The fixing unit according to claim 5, wherein the temperature-sensitive shut-off devices are thermal fuses.
- 10. A fixing unit that fixes a developing material deposited on a recording medium by heating and pressing the recording medium, comprising:
a first number of heating members that apply heat to the recording medium; a second number of switches; and wherein each of the first number of heating members receives electric power through a series circuit of the second number of switches, each of the second number of switches responding to a surface temperature of a corresponding one of the first number of heating members so that when the surface temperature exceeds a predetermined value, the electric power is shut off.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-204726 |
Jul 2001 |
JP |
|
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of copending U.S. application Ser. No. 10/153,534, filed May 21, 2002, entitled “FIXING UNIT,” the entire disclosure of which is incorporated herein by reference.
Continuations (1)
|
Number |
Date |
Country |
Parent |
10153534 |
May 2002 |
US |
Child |
10448845 |
May 2003 |
US |