Scan Part - Samsung SCX4521F - B/W Laser - All-in-One Service Manual

System Overview
Synchronous Serial Interface Control.
A/D Converter(10-bit, 2channel).
General I/O Port control.
Tone Generator.
RTC with calendar function.
S/W Assistant function(Rotator)
- Flash Memory : Stores system program and can be updated to the newer system program code through
the PC interface. It stores the FAX Journal List, One Touch dial number, speed dial number, and machine
configuration setup data.
Capcity : 2 Mbyte
Access Time : 70 nsec
- SDRAM : SDRAM is used for Print Buffer, Scan buffer when scanning, ECM Buffer when FAX Receiving,
and system working memory.
Capacity : 16 Mbyte
Access Time : 66MHz based on system bus clock.
Data Backup : 72 Hours
Backup Battery Charging Time : 100hours when completely discharged.

3.2.2 Scan Part

1) Image Signal Input Part
- Image Signal from CIS has a level of about 1.2V and is goes to ADC of Chorus2.
After ADC, CIS analog signal will be converted to 8-bit Digital signal.
2) Image Processing
- On the surface of the original paper, the light from the CIS LED reflected and goes to the CIS Sensor.
Then the light is converted to the appropriate voltage suitable for ADC input. Analog signal from CIS
sensor is used for ADC input then is converted to 8-bit digital data. Image processor of the Chorus2 will
do the Shading correction function at first, then Gamma correction function next. After then, the data goes
to different module according to the copy or FAX resolution mode. When Text mode, the image data
goes to LAT module, when Photo mode, the image data goes to Error Diffusion module, when PC-Scan
mode, the image data goes directly to the PC through DMA access.
Summary of the Image sensor interface is as below;
Service Manual
3-6
- Minimum Scan Line Time :1.5ms
- Scan Resolution : 600*600 dpi
- Scan Width : 208mm
- Function
White Shading Correction
Gamma Correction
CIS Interface
256 Gray Scale
Samsung Electronics