Lexmark T62X, Service Manual

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Diagnostic Aids
3-37
4069-5XX/7XX
are driven down into the stack increasing the normal force and drive
force until the bending strength of the paper is overcome and the
paper bends and moves up the dam. Once this critical threshold is
achieved the normal force remains at a level just high enough to
reliably feed the paper. Rather than having a fixed spring force for
feeding all weights of paper like the D-roll, this device has its own
mechanical logic for producing only enough pick energy to feed a
single sheet of paper regardless of its stiffness.
High normal force is one of the most significant contributors to
double feeding paper. The pick arm is counter balanced by an
extension spring located on the pick arm to reduce weight in the rest
state. This spring is factory set to exert no more than ten to fifteen
grams on the stack. This is as light as can be realistically set and
always guarantee there is some force to start the auto compensating
phenomena. This spring is not to be considered an adjustment for
feeding problems unless it is obvious that the pick arm cannot fall all
the way down to the bottom of the tray or has come loose.
Poor gear efficiency can cause the arm to generate higher normal
forces. If the pick assembly is noisy, replacement may be required.
The arm must pivot freely through its full range of motion. On 500
sheet trays there are wrap springs located on the pivot arbors of the
arm. These springs aid to prevent the arm from bouncing. If the arm
appears to be binding or sticky near the bottom of the tray these
springs may be the problem. Reducing the tension on the
counterbalance spring may be used as a temporary fix to get
additional weight at bottom, until the pick assembly can be replaced.
However, the counterbalance spring is not to be considered an
adjustment for feeding problems.
Autoconnect System, Paper Tray Options,
Envelope Feeder and Output Expander
Operations
Electrical
Autoconnect Cabling and Connectors
The printer options make electrical connection automatically or
autoconnects requiring no external cables when the option is