(2) Scanner section
1) How to scan documents
The scanner has sensors that are arranged in a line. These sensors
scan a certain area of a document at a time and deliver outputs se-
quentially. When the line is finished, the next line is scanned, and this
procedure is repeated. The figure below shows the case where the lat-
ter two sections of an image which are scanned are shown with solid
lines and the former two sections which are being transmitted are
shown with dotted lines.
The direction of this line is called “main scanning direction,” and the
scanning direction “sub scanning direction.”
In the figure above, one line is divided into 4 sections. Actually, how-
ever, one line is divided into thousands of sections. For scanning, the
light receiving element called CCD is used.
The basic resolution indicates the scanner capacity. The basic resolu-
tion is expressed in dpi (dot/inch) which shows the number of light
emitting elements per inch on the document.
The basic resolution of this machine is 400dpi.
In the sub scanning direction, at the same time, the motor that drives
the optical system is controlled to scan the image at the basic resolu-
tion.
2) Basic structure of scanner section
1
Copy lamp (Xenon lamp)
2
Reflector (light conversion plate)
3
No. 1 mirror
4
No. 2 mirror
5
No. 3 mirror
6
Lens
7
No. 2/3 mirror unit
8
Copy lamp unit
9
CCD
10
Mirror motor
11
MHPS (Mirror home position sensor)
The scanner unit performs scanning in the digital optical system.
The light from the light source (Xenon lamp) is reflected by a document and passed through three mirrors and reduction lenses to
the CCD element (image sensor) where images are formed. This system is known as the reduction image sensor system. Photo ener-
gy on the CCD element is converted into electrical signals (analog signals). (Photo-electric conversion). The output signals (analog
signals) are converted into digital signals (A/D conversion) and passed to the MCU (main control/image process section). The resolu-
tion at that time is 400dpi.
The mirror unit in the scanner section is driven by the mirror motor.
The MHPS is provided to detect the home position of the copy lamp unit.
(6)
(5)
(4)
(3)
(2)
(1)
(10)
(11)
(9)
(8)
(7)
1
2
3
4
5
5
4
3
2
1
Sub scanning direction
Sensor scanning area
Main
scanning
direction
Original
Image data sent to the ICU PWB
To MCU PWB
AL-1000/1010
7-2
