Lexmark X925 7541-03 series, Service Manual

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Service Manual
7541-03x
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Step 4b: Second transfer
Once the four planes of color are transferred to the transfer belt from the photoconductors, the image is carried
towards the transfer roll. This transfer roll is mounted on the duplex unit. The paper passes between the transfer
belt and transfer roll when the image on the belt reaches the second transfer area. The timing of the paper
reaching the second transfer area is determined by the registration rolls located in the paperfeed unit.
The high-voltage power supply sends voltage to the transfer roll to create a positive charge. Once the image on
the transfer belt reaches the transfer roll, the negatively charged toner clings to the media and the entire image
is transferred from the transfer belt to the media.
Service tips
•
If the transfer roller has nicks, pits, or flat spots on it, the surface doesn’t come into contact with the
media and transfer unit properly. This will cause voids or light spots on the page or repeating voids/
light areas, because the toner can’t be fully transferred due to the charge difference in the areas of
damage.
•
If the transfer roller does not engage the transfer unit, or does not have voltage coming from the high-
voltage power supply, the toner will not fully transfer from the transfer unit; the entire page will be very
light or blank. Any toner that does transfer will be due to a “contact” transfer instead of a “charge”
transfer. Check the high-voltage power supply contacts to the transfer roller.
About +1500v
Second transfer
roller
(Transferred on
a sheet of paper)
Sheet of paper
Transfer belt