Ricoh D124 Detailed Descriptions Manual page 31

Bypass Feed
 When a sheet of paper is inserted manually from the front of the machine, the
bypass sensor (16) detects the presence of the paper and signals the machine to
grab the paper and feed it into the bypass path.
 When the trailing edge of the paper being fed toward the back of the machine
passes the DRESS sensor (14), the sensor starts a pulse count and feeds edge of
the paper as far as the registration standby position and stops. (The DRESS
sensor knows how far to allow the paper to feed because the paper size was
previously selected with the User Tools.)
 The carriage unit makes one pass over the paper so the DRESS sensor can
detect the side edges of the paper and determine the width of the paper. This
information is for image registration (the calculations to determine the starting
point for printing the image).
Detailed Descriptions 25 D124