Riso RP-255, Technical Manual

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FB ORIGINAL SCANNING SECTION
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4. Stage-Glass Original Detection Mechanism
The flatbed original detection sensor checks whether an original has been placed on the stage glass. As
soon as the stage cover is closed halfway, blocking the light path to the stage-cover sensor, the flatbed
original detection sensor checks whether there is an original on the stage glass [A]. If the flatbed original
detection sensor is receiving light (original present), the indication on the panel changes to “Ready to
make master” (RN20/21 Series: Master/Print indication changes to “Master”), then the lamp illuminates
and the shading-compensation and auto-base-control operations are performed. The lamp carriage is
then sent to the scanning standby position. If the Start key is pressed within 60 seconds, the scanning
operation starts.
If the Start key is not pressed within 60 seconds, the lamp turns off and the lamp carriage is returned to
the home position.
5. Flatbed Automatic Base Control
When an original is set and the stage cover is closed, or when the original scanning density is set to
AUTO and the operation starts from the home position, flatbed auto base control (ABC) is conducted
after shading compensation is performed.
With an original set on the scanner table, when the cover open sensor turns ON or the Start key is
pressed, the lamp illuminates and the flatbed read pulse motor rotates in the feed direction. After the
FB/AF HP sensor switches from ON to OFF, the motor operates for a distance of 47 mm, pauses for a
set period of time, and then performs the shading compensation operation while operating for a distance
of 3.5 mm. It then moves a distance of 16.5 mm (10 mm from the leading edge of the original), and the
image sensor scans the surface density of the original. After this, the lamp carriage moves
approximately 2.5 mm twice and scans the surface density of the original. (Total 3 times)
The flatbed read pulse motor then operates in reverse (in the return direction) to return the lamp carriage
to the scanning standby position, and proceeds to FB scanning operation.
2.5 mm 2.5 mm
10 mm
6.5 mm 3.5 mm
15 mm 32 mm 8 mm
Auto-base-control operation Shading-compensation operation area
FB/AF HP sensor
Home Position
(HP)
Scanning standby position
Gain adjustment position
1107