Service Manual
6-13
Troubleshooting
6
Printing and print quality problems
Print problems fall into the following five categories:
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Streaks or lines in the prints
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No printing
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Printing too light or too dark
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Image is offset or cut off
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Wrinkling
Streaks or lines in the print parallel to the long axis of printing
1.
Clean the thermal head. This is discussed in the Chapter 7 topic
“Cleaning.”
2.
If the streak (a dot-wide line of no printing) runs the entire length of
the page, the thermal head may have a blocked or defective heating
element. Replace the thermal head as explained in the Section 8 topic
“Thermal head” on page 8-18.
Streaks or lines in the print parallel to the short axis of printing
1.
Inspect the drum drive system. Ensure that the drum rotates
smoothly. If necessary, remove the drum drive belt from the drum
pulley so that you can rotate the drum and determine that it smoothly
rotates in its bearings.
2.
Ensure that the drum drive belt is properly tensioned. Refer to the
Chapter 9 topic “Adjusting for best print quality” on page 9-16.
3.
Check the drum motor by measuring the resistance of its windings.
Refer to Table 6-1 for the expected winding resistance values. If one or
all of the windings are out of value, replace the motor. Refer to the
Section 8 topic “Drum motor” on page 8-26.
4.
Test the torque limiter located next to the right end of the transfer roll's
supply spool. It should rotate in one direction only, and it should offer
a small amount of resistance to being turned. The torque limiter
supplies a constant amount of back-tension to the motion of the
transfer roll to keep it taut.
Required tools
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#1 POSIDRIV® screwdriver
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Volt-ohm
-meter (VOM)