Toshiba e-STUDIO351c Service Handbook page 506

2) Uneven pitch and jitter image
<Symptoms>
Original mode
All modes Occurs cyclically at right
angles to paper feeding
direction
Cause/Section Step
1
Drum 2
3
Drum rotation 4
abnormality
5
Inadequate 6
main motor
rotation speed
Drum coupling 7
Transfer belt 8
9
10
11
Laser optical 12
unit
e-STUDIO281c/351c/451c TROUBLESHOOTING
Location
Uneven pitch
Check Item
Test printing (A3/LD)
Are there uneven pitches approx.
283 mm?
Is there any damage on the drum
surface?
Check the main motor operation in
the test mode (03) to see if there is
any rotation abnormality of the drum.
Check the main motor operation in
the test mode (03) to see if there is
any rotation abnormality of the drum.
Check the value set for main motor
rotation speed. (Is the value signifi-
cantly different from the default
value?)
Loose coupling, damage, deforma-
tion
Is the belt tension of the driving unit
normal?
Deformation or damage of the trans-
fer belt
Stain or damage of the drive roller
Large driving load due to the peeling
of the cleaning blade
Check the halftone pattern to see if
there are uneven pitches of approx.
0.3 mm each in the whole image.
Phenomena
Feeding
direction
Measure
Output the built-in halftone
and grid patterns.
Replace the main motor.
Clean or replace the
drum.
Replace the main motor.
Reconnect the connec-
tors.
Replace the harnesses.
Replace the LGC board.
Reset main motor speed
to 128.
Tighten the screws if they
loosen. Or replace the
couplings.
Adjust the tension of the
transfer belt.
Replace the transfer belt.
Clean or replace the drive
roller.
Replace the cleaning
blade.
Replace the laser optical
unit.
5 - 114
Fig. 5-2
Remark
For the following
checks
Check the halftone
pattern.
(Uneven pitch:
approx. 2.5 mm)
Check the halftone
pattern.
(Uneven pitch:
approx. 75 mm)
Check the halftone
pattern.
(Uneven pitch:
approx. 75 mm)
Check the halftone
pattern.
(Uneven pitch:
approx. 0.3 mm)
June 2005 © TOSHIBA TEC