Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
FIXING DEVICE
Document Type and Number:
Japanese Patent JP2001194950
Kind Code:
A
Abstract:

To provide a fixing device equipped with a protective circuit which operates by detecting an AC power voltage applied to a fixing roller, even when an insulating layer of the fixing roller is in the middle of insulation deterioration.

In the fixing device equipped with a fixing roller 40 constituted by laminating a planar heating element 42 through an insulating layer 44 on the inside wall of a metal cylindrical body 43, and the protective circuit 51 for preventing overheating of the planar heating element 42 by a breakdown between the metal cylindrical body 43 and the planar heating element 42, the protective circuit 51 has a reference voltage generating circuit 36 which generates the reference voltage, a voltage detection circuit 34 which detects the voltage of the metal cylindrical body 43, an abnormality detection circuit 30 which outputs an abnormal detecting signal when a detection voltage exceeds the reference voltage by comparing a detection potential detected by the voltage detection circuit 34 and the reference voltage, and a cutoff circuit 22 which detects an abnormal detecting signal and intercepts an electric power supplied from a power source to the planar heating element 42.


Inventors:
HASEGAWA TAKAHIKO
Application Number:
JP2000078926A
Publication Date:
July 19, 2001
Filing Date:
March 21, 2000
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
RICOH KK
International Classes:
G03G21/00; G03G15/20; G05D23/19; H05B3/00; (IPC1-7): G03G15/20; G03G21/00; G05D23/19; H05B3/00