Lexmark X500n Service Manual page 123

Lexmark confidential until announce edited 1/4/2007 7100-XXX
Second transfer
Once the last plane of color is transferred to the transfer unit from the photodeveloper, media is picked from
the paper tray and carried to the transfer roller. The transfer unit continues to rotate around and meets the
paper at the Transfer Roller area.
The high voltage power supply sends voltage to the transfer roller to create a positive charge. Once the
paper passes between the transfer roller and transfer unit, the negatively charged toner clings to the paper
and the entire image is transferred from the transfer unit. This is the 2nd transfer process.
Look at callout 4 in the picture below. This is the where the transfer unit transfers the toner to the media by
way of the transfer roller and Step 4b of the EP process.
Note: 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 lights 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.
Note: 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 transfer roller clutch and the high voltage power supply contacts to the transfer roller.
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Diagnostic aids