Gestetner G060 Service Manual page 529

Rev. 09/2003
Subject
Dirty background Dirty background may
continuously appear on the
left side (relative to paper
feed) under very low
temperature and humidity
conditions.
Dirty background may
intermittently appear with
originals that have a high
image area ratio after making
multiple prints of originals
with a low image area ratio.
Fireflies Fireflies may appear with
originals that have a high
image area ratio after making
multiple prints of originals
with a low image area ratio.
SM
Symptom
When the developer has deteriorated or
when prints are made in a very low
humidity condition, dirty background may
appear continuously.
While making prints with a low image
area ratio, the toner-carrier attraction
tends to increase. Then, when a large
amount of toner is supplied under this
condition, the supplied toner cannot be
properly charged, causing toner to flow
out from the development unit.
While making prints with a low image
area ratio, developer is agitated with less
toner supplied. This may cause some
toner to coagulate and harden. Then,
when switching over to originals with a
high image area ratio, this toner may
cause fireflies.
Cause
Perform forced toner refresh mode (SP3-921-1 or
2).
The machine automatically does this in the
following sequence. (It takes about 20 minutes to
complete this mode.)
1. Consumes toner in the development unit
without toner supply until toner end is detected.
2. Starts toner recovery mode.
3. Starts process control self-check.
NOTE: It takes about 20 minutes to complete this
Change the settings of the following SP modes:
SP3-906-1 Job End Process Control Self-check
200 (Default) to 100
SP3-920-3 OPC Refresh – Prints
200 (Default) to 100
SP3-920-6 Toner Refresh Mode
0 (Default: Disable) to 1 (Enable)
During the above mode, toner refresh will
automatically be done after job end process
control self-check, and will consume the
coagulated or overcharged toner.
SP3-125-3 Auto TD Adjust
Default 0 (Disable) to 1 (Initial process control)
Making prints with a low image area ratio causes
the toner-carrier attraction to increase, resulting in
low image density. Activating the Auto TD
Adjustment corrects toner density within the target
range; however, it takes up to 6 minutes to
complete the self-check and Auto TD Adjustment.
4-47
TROUBLESHOOTING GUIDE
Action
mode, to prevent carrier flowing out.
G570