Canon NP6218, FY8-13EX-000 service manual The copy has uneven density front too dark, 10-52

CHAPTER 10 TROUBLESHOOTING

4.The copy has uneven density (front too dark).

5.The copy has uneven density (front too light).

Cause	Step	Checks	Results	Action
Scanner	1	Clean the scanning lamp, reflect-	YES	End.
		ing plate, side reflecting plate,
		mirror, lens, and dust-proofing
		glass. Is the problem corrected?
Primary	2	Execute ‘No. 402’ in service mode	YES	End.
charging roller		(primary charging roller cleaning).
		Is the problem corrected?
Transfer charg-	3	Execute ‘No. 403’ in service mode	YES	End.
ing assembly		(transfer roller cleaning). Is the
		problem corrected?
	4	Make several blank (white) copies.	YES	End.
		Is the problem corrected?
	5	Is the transfer changing roller	NO	Re-insert the charging
		securely inserted?		roller.
	6	Are the position and condition of	NO	Corrector replace the
		the pressure spring of the transfer		spring.
		charging roller normal?
Pre-exposure	7	Does the pre-exposure lamp turn	NO	See “The pre-exposure
lamp		on during copying operation?		lamp fails to turn on.”
Developing	8	Is the developing cylinder coated	NO	Take out the developing
assembly		with a uniform layer of toner?		assembly, and shake it
				several times; then,
				make copies. If the
				problem is not corrected,
				replace the developing
				assembly.

10-52 COPYRIGHT © 1997 CANON INC. CANON NP6218 REV. 0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)