InoTec SCAMAX 2600, Руководство по обслуживанию

Страница: 53 / 68

SCAMAX
®
2600/4000
Tech. Manual 06/2002 T-53
3.12 Optical Components Unit
The optical components unit covers the light path of the front camera and the same for the back camera if
fitted.
Components for both paths and their mode of operation are identical. Merely their positioning in the
scanner is different.
Each path consists of:
a small mirror
a large mirror
a lens 3,5/50 mm with colour filter (bitonal) or 6,4/60 mm (colour).
As can be seen from the drawing each path is broken by two mirrors to keep outside dimensions of the
scanner as small as possible.
In a SCAMAX 2600/4000 duplex version the two miniature fluorescent tubes are held at each end by a
spring-loaded lamp housing. The two lamp holders are connected by a piece of sheet metal that also
prevents unwanted light emission upwards or downwards as appropriate.
The two tubes are somewhat offset and illuminate the front and back respectively of the document being
transported. The light reflected from the document contains the image information. It falls onto the smaller
mirror (1). This mirror transmits the light to the larger mirror (2) (angle of incidence = reflection angle),
which reflects it to the lens. The light captured by the lens is condensed onto the CCD array.
Since the document moves line by line between the two tubes image information is transmitted to the
CCD array of each camera on a line-by-line basis.
The start of the scan process must be exactly timed to be in sync with the feeding of the document. Since
there is no photocell to detect the leading edge of the paper the detection of a certain amount of light in
the CCD is used to signal 'leading edge of paper' (see also 'Flow of a normal scan process').