SCAMAX
®
2600/4000
Tech. Manual 06/2002
T-60
3.13.3 Paper Feed with Separation System
The initial feed rollers, consisting of three red rubber belts, are mounted on two levers. Its own weight
presses it onto the top document.
The lowest position of the initial feed rollers can be adjusted vertically via two set-screws (see above
"Document Feeder Adjustment"). This adjustment is necessary to prevent the feed belts rubbing directly
on the input hopper plate when no paper is present.
Paper feed is activated via an electromagnetic clutch located at the end of the shaft (see also "Flow of a
scan routine"). Power transmission to the clutch is via a gear wheel. It is separated from the drive
mechanism when the output hopper plate is lifted.
There are
normal feed rollers
made from aluminium and there are
heavy feed rollers
made from steel,
which are approximately three times heavier. With difficult or unusual paper the heavier edition can
improve paper feed due to the greater pressure being exerted.
The performance of the paper separation is largely dependent on many factors, but ultimately dictated by
the slip and/or sticking together of documents. If heavier pressure produces better results with one kind of
paper it may cause the opposite with another kind. The standard issue of aluminium rollers has been
proven to be the best compromise available for the majority of documents encountered.
The pushback roller, which prevents two or more documents being fed simultaneously, plays an important
part in paper separation. It is covered with a friction coating and its distance to the initial feed rollers can
be adjusted depending on paper thickness. The pushback roller turns slowly against the paper travel
direction. The main drive powers it via a round belt.
Normally the pushback rollers have
yellow friction coatings
. For documents difficult to separate there
are
white friction coatings
available that offer greater traction that pushes paper back firmer. Life
expectancy of the white covers is much shorter than for the yellow ones.
The paper thickness selector sets the distance between pushback roller and feed belts. A stepper motor
drives two eccentric discs via a toothed belt and drive shaft. The discs hold the pushback roller, shaft and
bearing in position against the pull of two springs.
When the scanner is turned on, or after a reset, the stepper motor executes a reference drive whereby a
nose on the left eccentric disc activates a microswitch. This position is also the position assumed when
paper separation is off, i.e. it represents the largest distance between feed roller and pushback roller.
Summary of Contents for SCAMAX 2600
Page 7: ...SCAMAX 2600 4000 Tech Manual 06 2002 T 7...
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Page 16: ...SCAMAX 2600 4000 Tech Manual 06 2002 T 16 Illustration of optical reduction...
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