Document Scanner Unit - Brother DCP-9010CN Service Manual

3.2.1

Document scanner unit

The document scanner unit is equipment which scans the paper using the CIS unit. This
machine prints the scanning data (copy) or data is sent by fax (fax transmission).
There are two kinds of scanning method of the document scanner unit. One is operation to
scan with the document scanner unit, the paper is placed on the document glass, the CIS unit
moves is the bottom of it, and it scans the paper, and other is operation to scan in connection
with the ADF unit, scan the paper which has been sent over the immovable CIS unit.
(1) CIS unit
The CIS unit includes the contact image sensor (CIS) (Resolution of horizontal scanning:
Maximum1,200 dpi color scanning).
The light source is light-emitting-diode (LED) of the RGB. The RGB is changed at high
speed respectively, and lead the light from the document directly to the image pickup
device (CMOS image sensor) through the rod lens array, and the image is generated.
(2) Driving of the CIS unit
The CIS unit is supported by the CIS rail and assembled on the drive belt. When the CIS
motor is rotated counter clockwise, the CIS unit on the drive belt scans the document
while sliding to the right hand side. In this case, the CIS unit has the capacity to scan at
2,400 dpi resolution of sub scanning.
(3) The CIS unit home position detection (FB home position detection)
The CIS unit is configured at the FB home position to determine the scanning position of
the sub scanning direction.
Based on the scanning position, the FB home position is detected when the home
position sensor inside of the document scanner unit.
(4) White level compensation
Whenever the variation of the CIS unit, the correction of the time degradation and the
value of the white color scans, in order to make them not different.
The white level compensation keeps a fixed value of the white color by scanning the
white-level reference film inside the document scanner unit with the CIS unit.
2-6
Confidential