System Construction - Samsung ML-2251N/XAA Service Manual

4.2 System Construction

4.2.1 Summary
The ML2250 consists of the following main functional components
1) The Firmware
This controls the whole printing process
2) The Print Engine consisting of
a) Engine frame
b) Paper feed mechanism
The paper mechanism cosists of a 250sheet main cassette, multi-purpose paper tray, pickup rollers, friction
pads and feed rollers. Together with sensors in the feed path these serve to control paper registration and
guide the paper through the Image transfer, image development, image fusing and exit assemblies. The
paper path has an anti-static connection to earth to eliminate paper feed problems due to static charge on
the paper.
c) Main drive mechanism
The main drive is a Bi-polar 2 phase motor. It drives the OPC, Paper Pick-up and paper feed rollers using a
gear train mechanism
d) Image development unit
Using a Laser Scanning Unit (LSU) this section of the mechanism creates the image on the OPC drum
(part of the integrated toner cartridge).
e) Image transfer unit
The function of the this unit uses High Voltages supplied by the HVPS to move the image from the developer
unit onto paper.
f) Image fusing unit
The function of this unit is to permanently fix the toner image onto the paper. This is achieved usibg a
temperature controlled heating unit (the fuser).
g) Electronics PBA including
i) Main control board consisting of
(1) Main processor Asic (166MHz SPGPm)
(2) Memory parts (Flash Rom containing the control program and DRAM for working memory)
(3) Engine interface parts (motor control, fuser control, HVPS control, sensors etc)
(4) PC Interface (USB , Parallel, Network – wired and wireless)
(5) Bus, DMA and I/O handling
ii) Operators panel
iii) PC Interface
Samsung Electronics
Summary of product
Service Manual
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