Specifications

AL-1551 OPERATIONAL DESCRIPTIONS 7-2
2. Scanner section
A. 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
sequentially. When the line is finished, the next line is scanned, and this
procedure is repeated.
The figure below shows the case where the latter 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 below, one line is divided into 4 sections. Actually, however,
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 resolution
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 resolution.
B. Basic structure of scanner section
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 energy 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 resolution 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.
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
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)
(6)(5)
(4)
(3)
(2)
(1)
(10)
(11)
(9)
(8)
(7)