Gestetner B147 Service Manual page 265

Subject
Toner blasting (1) Toner may blast, causing
smeared text characters
and/or lines in 2C or process
black mode (depending on
the PDL setting or type of
paper used.)
Toner blasting (2) Black toner may blast on the
2nd side of paper under the
low temperature.
Image density change When the machine is tuned
(1) on in the morning (having
been unused for a while), the
ID of the initial outputs may
be relatively low or high, in
which case the machine
needs to compensate by
raising or lowering the ID
during machine operation.
B147/B149/B190
Symptom
An excessive amount of toner is used for
development.
Black toner moves on the paper during
transport to the fusing section, due to
discharge from the toner to the
surrounding guide plates.
When the machine is off, the
environmental conditions can begin to
affect the machine's development
capability. When the main switch is
tuned on, the machine starts a process
control self-check and adjusts the
development parameters to achieve the
proper development potential gap
without adjusting the toner
concentration. Over the course of the
print operation, the ID will then get closer
and closer to the target level.
Cause
Change the toner limit setting in SP mode.
• If toner blasted images appear for text or lines
in 2C, decrease the setting for Text from 190%
to 150 - 170%.
• If toner blasted images for text and lines
recognized as pure image data (i.e. not
processed as text/line data), decrease the
setting for Photo from 260% to 170 - 190%.
NOTE: If the toner limit is lowered too much, it
may cause the density of shadow areas to be not
smooth.
Increase the paper transfer current in SP data
from the default setting to a recommended value
depending on the mode selected as shown below.
SP2-301-3 ([K] 125mm/sec): "16" to "21"
SP2-301-4 ([K] 180mm/sec): "27" to "32"
SP2-301-16 ([FC, K] 125mm/sec): "9" to "13"
SP2-301-17 ([FC, K]180mm/sec): "15" to "20"
NOTE: If the toner limit is lowered too much, it
may cause the density of shadow areas to be not
smooth.
If this is often pointed out by users who are very
particular about image density, turn on Auto TD
Adjustment (SP3-125-003) as a solution.
NOTE: It takes about 5 minutes to complete the
self-check.
4-63
TROUBLESHOOTING GUIDE
Action
SM