Of The Separation/Pre-Transfer Corona Current - Canon NP6251 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
5. Controlling the DC Component of the Separation/Pre-Transfer Corona Current
If an overcurrent flows into the separation/pre-transfer charging assembly, the high-
voltage stop signal (HVTOFF) is generated to temporarily stop the corona current
(DC/AC component) applied to the pre-transfer/separation charging assembly.
When HVOFF is generated, the copier continues to operate, and the application of
the corona current will be resumed when the application current returns to normal.
If leakage occurs because of an overcurrent caused by a broken charging wire or the
like, and HVTOFF continues as a result, the application will not be resumed unless the
cause is removed.
When the corona current applied to the transfer/separation charging assembly
stops because of an overcurrent, separation jams tend to occur frequently.
Since the control panel will not indicate any message, check the relevant
mechanisms if separation jams are frequent.
Signal* DCON
HVT output J114A-10
Pre-transfer ON
Pre-transfer OFF
Separation ON
Separation OFF
*Output from the DC controller PCB (connector of signal name).
Table 4-104 Combinations of Transfer/Separation Signals
4-18
COPYRIGHT © 1997 CANON INC.
Switching signals
HVT.POST.AC
J114A-7
'1' '1'
'0' '0'
'1' '1'
'0' '0'
ACBTP ROED
J114A-3 J114A-1
'1' '0'
'0' '0'
'1' '0'
'0' '0'
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
Control signals
HVSTC HVT.POST.DC
J114A-8 J114A-9
— 3~11V
— 2V
3~11V —
2V —