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I-11
Poor fixing
Possible cause
Step
Check
Result
Remedy
Printing paper
1
Is thick paper more than 36 lb.
being used?
Yes
Instruct the user to
use paper of the
recommended
thickness.
Toner sensing
failure
2
Is the problem solved by replacing
the drum unit or the toner cartridge?
(When printing is faint.)
Yes
Toner is empty.
As toner sensing is
defective, clean the
toner sensor.
If the wiper of the
toner cartridge id
broken, replace the
toner cartridge with a
new one.
Fixing unit nip
failure
3
Is the nip width in the fixing unit
insufficient?
Is the nip spring (P/R spring)
unconnected?
Yes
Connect the spring
or replace the fixing
unit.
Thermistor
failure
4
Measure the temperature of heat
roller surface during printing.
Is the temperature correct (160°C)?
No
Replace the fixing
unit.
Summary of Contents for HL-720
Page 1: ...SERVICE MANUAL MODEL HL 720 730 730Plus R LASER PRINTER ...
Page 36: ...II 19 1 3 10 Engine I O HL 720 Fig 2 21 shows the engine interface circuit Fig 2 21 ...
Page 37: ...II 20 HL 730 730Plus Fig 2 22 shows the engine interface circuit Fig 2 22 ...
Page 61: ... Fig 3 18 2 4 1 1 1 ...
Page 92: ...SERVICE MANUAL MODEL HL 760 R LASER PRINTER ...
Page 109: ...II 8 1 3 4 DRAM Two 4M bit DRAMs x 16bits are used as the RAM Fig 2 6 ...
Page 113: ...II 12 1 3 10 Engine I O Fig 2 12 shows the engine interface circuit Fig 2 12 ...
Page 114: ...II 13 1 3 11 Paper Feed Motor Drive Circuit Fig 2 13 ...
Page 133: ...Appendix 2 Main PCB Circuit Diagram 1 3 CODE UK3227000 B48K272CIR 1 3 NAME ...
Page 134: ...Appendix 3 Main PCB Circuit Diagram 2 3 CODE UK3227000 B48K272CIR 2 3 NAME ...
Page 135: ...CODE UK3227000 B48K272CIR 3 3 NAME Appendix 4 Main PCB Circuit Diagram 3 3 ...