Gestetner G060 Service Manual page 532

TROUBLESHOOTING GUIDE
4.5.2 COLOR SHIFT
The following briefly explain the factors causing color shifts and what to do on the machine to correct it:
• Temperature change causes the optical components in the
laser optics housing unit to contract, causing the main
scan magnification to change. To correct the line position,
the machine automatically does the line position
adjustment when the temperature changes by 5
the last position adjustment.
If the line position adjustment functions properly, no color
shift occurs. If the line position adjustment fails (result:
SP5-993-7), color lines may shift anywhere on the outputs.
• The process speed at each stage (registration roller,
transfer belt, and fusing belt/roller) affects the paper
transport speed. If the paper transport speed changes
during image transfer of a color, the color line being
transferred shifts with respect to the color line already
transferred to the paper. The registration roller speed
(adjusted by color development motor speed) and fusing
belt/roller speed (adjusted by black development motor
speed) are adjusted by the manufacturer.
Paper speed may slightly change due to the type of paper
used or after replacing the parts related to the drive
sections of the registration section, transport unit, and
fusing unit. (After replacing the fusing unit, the speed
adjustment should be done in the User Program mode.)
Also, the position where color shift occurs depends on
which section starts moving at the incorrect speed.
• Paper skew directly affects the color shift between the
front and rear sides. There are several factors. One of
them is the position of the side fences.
G570
o
C since
The black drum motor drives
the registration rollers and the
motor speed is not adjustable.
4-50
The black development motor drives
the registration rollers and the motor
speed is adjustable in SP mode.
The color development motor drives
the registration rollers and the motor
speed is adjustable in SP mode.
Rev. 09/2003
G060T503.WMF
SM