b. Protection with the Signals from the SSRIf the fixing heater continues to remain on because of a short circuit in the SSR, theDC controller PCB generates the error auto power-off signal (PWOFF*) to turn off thepower switch.The copier’s fixing heater drive SSR sends the SSR drive signal (MSSRD, SSSRD)to the DC controller PCB when the SSR is ON; the DC controller PCB also monitors theheater drive command (MHRD, SHRD) and the SSR drive signal (MSSRD, SSSRD) atthe same time.If the main SSR drive signal (MSSRD) is ‘1’ when the main heater drive command(MHRD) is ‘0’, the DC controller PCB will assume the condition as an error in the SSRand will indicate ‘E004’ on the control panel. In about 2 sec thereafter, it generates theerror auto power-off signal (PWOFF*) to turn off the power switch.c. Protection with a ThermistorIf the internal temperature of the thermal switch (TSW1) exceeds about 208°C, thethermal switch turns OFF to cut off the power to the fixing heater.If the thermal switch turns OFF, the error auto power-off signal (PWOFF*) will begenerated in about 1.5 sec to turn off the power switch.Reference:Once its contact opens, the thermal switch (TSW1) will not return to normal even atambient temperature. It may be used once again by cooling it to 0°C or less.d. Recovery after Activation of the Protection MechanismIf the error auto power-off signal (PWOFF*) has been generated, remove the cause,and turn on the power switch to recover.If ‘E000’, ‘E001’, ‘E002’, ‘E003’, or’E800’ has been indicated, remove the cause, andexecute ‘401’ in service mode [4] to recover.Reference:When selected in user mode, “auto power-off” will also turn off the power switchwhen activated. To distinguish from such “auto power-off,” this manual refers to theforegoing auto power-off as “error auto power-off.”6-6CHAPTER 6 FIXING SYSTEMCOPYRIGHT © 1997 CANON INC. CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
