Service manual

30 July, 2001 TROUBLESHOOTING GUIDE
4-43
Action Required
Direction Area Symptom Possible Cause
Output Mode SP Mode
Procedure / Remarks
Entire
image
Color shifts on the
entire image and
amount of shifts is
almost the same at
front, center, and
rear sides.
(Refer to pattern 4
on page 4-45 for the
symptom.)
Main-scan
registration is not
correctly
adjusted.
- SP5-993-
010 (Y)
SP5-993-
011 (M)
SP5-993-
012 (C)
Measure the gap between the black line and other
colors (YMC) using a magnification scope.
Convert the measured value [µm] to [dots] with the
following formula. Then, add or subtract the calculated
dot value in the SP mode.
Correction [dots] = Measured value [µm] / 21.2
If color (YMC) has shifted to the left in relation to black,
add the above value to the current setting.
If color (YMC) has shifted to the right in relation to black,
subtract the above value from the current setting.
Examples
• If the magenta line has shifted to the left by 40µm,
add 4 to the current setting of SP5-993-011
Correction [dots] = +(40/21.2) = Approx. +2
• If the magenta line has shifted to the right by 70µm,
subtract 3 from the current setting of SP5-993-011.
Correction [dots] = -(70/21.2) = Approx. -3
Main-scan
Front or
rear
The amount of color
shift at the front and
rear sides becomes
gradually bigger
toward the trailing
edge.
• Side fence
position
• Transfer belt
position
--
• Check if the side fences of the paper trays are
properly positioned. If there is clearance between the
paper and the side fences, this causes paper to skew
during paper transport.
• Check if the transfer belt is in correct position, if the
tension springs are properly set, or if the paper
attraction roller is properly installed..
(☛ 3.7.4 Transfer Belt)