Samsung SCX-4521F Series Service Manual page 167

-SDRAM : SDRAM is used for Print Buffer, Scan buffer when scanning, ECM
3. 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;
3) CIS Driving Part
4) ADF Driving Part : Driving ADF Stepper motor, and the maximum motor speed is
Buffer when FAX Receiving, and system working memory.
.Capacity : 16 Mbyte
.Access Time : 66MHz based on system bus clock.
.Data Backup : 48 Hours
.Backup Battery Charging Time : 100hours when completely discharged.
① Minimum Scan Line Time : 1.5ms
② Scan Resolution : 600*600 dpi
③ Scan Width : 208mm
④ function
- White Shading Correction
- Gamma Correction
- CIS Interface
- 256 Gray Scale
- CIS Supply Voltage : +3.3V
- CIS Max frequency : 5MHz
- CIS Line time
Fax/Copy - 1.5ms
PC-Scan - 4.5ms
- White output volt. : Max 0.8V
2000PPS.
- MOTOR DRIVER : A3978(Allegro)
- Driving Voltage : 24V DC