Samsung ML-3471ND/XAX Service Manual page 29

Product specification and feature
2.2.3.1(d) Flash Memory
It stores the system program and downloads system program through the PC Interface.
Capacity : 16M Byte (NOR Flash)
Access Time : 90ns
Page read Time : 25ns
2.2.3.1(e) SDRAM
It is used as swath buffer, system working memory area, etc. while Printing.
Capacity : The 64M Bytes is for this model (64M : Printing System Working Memory Area)
2.2.3.1(f) Sensor Input Circuit
Paper Empty Sensing
The Paper empty sensor (Photo Interrupter) on the HVPS informs the state of paper to CPU whether it is empty or not
with operation of the actuator.
When cassette is empty, it detects the fact by reading the E20 of CPU, and then informs the fact by displaying the RED.
MP Sensing
By operation of Actuator on the frame, an individual MP Sensor (Photo interrupter) informs the state of paper to CPU
whether it is empty or not. It reads the D17 of CPU for recognizing paper in MP, and paper is fed from MP if there is.
Paper Feeding/With Toner Cartridge Sensing
When paper passes the actuator (feed sensor part), it detects the signal of Photo interrupter, informs the paper feeding
state to CPU, and then sprays the image data after certain time.
If it doesn t detect the feed sensor within 1sec. after paper is fed, paper Jam0 is occurred (LED will be display RED
color). The fact whether the developer is inserted or not is detected by CRUM. After the developer is mounted, the sub-
CRUM can read the information of toner cartridge from contact with CRUM involved in toner cartridge. If the information of
toner cartridge is invalid, it will show invalid sign on a LCD or LED.
Paper Exit Sensing
It detects paper state whether paper gets out from the set with operation of exit sensor on the HVPS and actuator on the
frame. Paper detects the on/off time of exit sensor by reading D22 of CPU, and the normal operation or jam information is
informed to the CPU.
The paper JAM2 is informed. (LED will be display RED color)
Cover Open Sensing
The Cover open sensor is located on the HVPS. After the front cover is opened, +24VS (DC fan, Solenoid, Main Motor,
Polygon motor part of LSU and HVPS), which is supplied to the each unit, is cut off. The cover-open sensing is operated
by the D23 of CPU.
In case, the red will be ON for informing the facts to user.
Service Manual
2-20
Samsung Electronics