Toshiba ESTUDIO170F, Руководство по обслуживанию

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e-STUDIO170F Circuit Description January 2005 © TOSHIBA TEC
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7.3.2 Scanning Control Circuit
Fig.7-20
The scanning control circuit consists of the CIS (Contact Image Scanner), DSC (IC27), ASIC (Engine
controller: IC15), SDRAM (IC1), and other peripheral devices. It scans and converts documents to
image data (raster data).
The CIS lights the LED when the LEDON signal output from the DSC goes HIGH to turn on Q113.
Then, it scans the LED’s light reflected by a document and converts it to an analog image data. Since
light is reflected extensively by a white part of the document and then more light is sensed by the sen-
sor array, the amplitude of the analog image data becomes larger.
The DSC reads the SIG signal output from the CIS through the operational amplifier (IC20) according to
the timing of the XCLK signal and XSI signal. Then, it performs A/D conversion and shading correction,
gamma correction and binarizing process on the read analog image data and converts it to digital
image data.
The DSC serially transfers the digital image as an SD signal to the ASIC while synchronizing it with the
SDE signal and SDCK signal.
The ASIC converts the transferred serial image data to 16 bits of parallel image data (raster data), and
then transfers them to the SDRAM in DMA mode.
Signal Name Type Active Description Destination
LEDON O H LED lighting signal Q113
XCLK O - CIS drive clock CIS
XSI O - CIS line synchronizing signal CIS
SIG I - Analog image data IC20
MVSDA O - Serial image data DSC
MVSCK O - Serial image data transfer clock DSC
MVSENX O L Serial output effective period signal DSC
+24V
CN11
Sensor
array
LED
Q113
LEDON LED
VLED
CIS Main PBA
8
6
1
10
9
39 3 6
63
61
50
48
47
55
XSI
SIG
IC20
145
XCLK
MVSCK
MVSENX
MVSDA
146
147
IC27
DSC
IC15
ASIC
(Engine controller)
IC1
SDRAM
SDD0-15