Protection Against Abnormality; Jam Detection Control - Konica Minolta bizhub 500 Service Manual

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18. FUSING SECTION

Protection against abnormality

When the thermistors /1 (TH1) and /2 (TH2) detects a stipulated temperature (233°C) 5 times at the prescribed

intervals, this is deemed to be a high temperature abnormality and the fusing heater lamps /1 (L2) and /2 (L3) are

turned OFF. The thermostat (TS) also monitors an abnormal temperature rise and, when the detected tempera-

ture gets to 220 ± 10°C, the AC power lines to L2 and L3 are shut off.

For each condition in the warm-up, print, stand-by and the low power modes, the detected temperatures of

TH1 and TH2 and the number of times when L2 and L3 turned ON are calculated. And it is considered that a

low temperature abnormality occurs when certain conditions are met. When a low temperature abnormality

occurs, the power supply to L2 and L3 is cut off.

When these fusing temperature abnormalities occur, the system is placed in the SC latch condition with a mes-

sage shown in the touch panel. After repairing with the cause of abnormality identified, it is necessary to release

the SC latch by the software DipSW3-1 for restoration.

Only while in the print, when the detected temperatures of the thermistors /1 (TH1) and /2 (TH2) go down in a

moment more than the prescribed temperature, this is considered as a wind-up jam and the operation of the

main body is stopped with a message shown in the touch panel.

Theory of Operation Ver1.0 Feb.2006

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