Samsung SCX-4520, Service Manual

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Summary of Product
Service Manual
4-7
Samsung Electronics
4.2 System Layout
The SCX-4720F/4520 is roughly made up Main Control part, Operation Panel part, Scanner part, Line Interface
part and Power part. Each Part is separated Module which focus on common and standard design of different
kind products. main control part adopting Fax & LBP Printer exclusive Controller is composed of 2 CPU and
1 Board. Scanner part is composed of ADF and Platen and is connected with Main by Harness.
4.2.1 Feeding section
There is a universal cassette which automatically loads paper and the manual feed which supplies paper single
sheet at a time. The cassette has a friction pad which separates paper to ensure single sheet
feeding, and it has a sensor, which checks when the paper tray is empty.
- Feeding Method: Universal Cassette Type
- Feeding Standard: Center Loading
- Feeding Capacity: Cassette-250 sheets (75g/m
2 , 20lb paper standard)
Manual 1 sheet (Paper, OHP, Envelop, etc.)
- Paper detecting sensor: Photo sensor
- Paper size sensor: None
4.2.2 Transfer Ass’y
This consists of the PTL (pre-transfer lamp) and the Transfer Roller. The PTL shines a light onto the OPC drum.
This lowers the charge on the drum’s surface and improves transfer efficiency.
The transfer roller transfers toner from the OPC drum surface to the paper.
- Life expectancy: Over 60,000 sheets (at 15~30°C)
4.2.3 Driver Ass’y
- Gear driven power unit. The motor supplies power to the paper feed unit, the fuser unit, and the toner
cartridge.
4.2.4 Fixing Part(Fuser)
- The fuser consists of the Heat Lamp, Heat Roller, Pressure Roller, Thermistor, and Thermostat. It fixes toner to
the paper using pressure and heat to complete the printing job.
4.2.4.1 Temperature-Intercepting Device (Thermostat)
The thermostat is a temperature sensing device, which cuts off the power to the heat lamp to prevent
overheating fire when the heat lamp or heat roller overheats.
4.2.4.2 Temperature Detecting Sensor (Thermistor)
The Thermistor detects the surface temperature of the heat roller, this information is sent to the main processor
which uses this information to regulate the temperature of the heat roller.
4.2.4.3 Heat Roller
The surface of the Heat Roller is heated by the Heat Lamp. As the paper passes between the Heat and Pressure
rollers the toner is melted and fixed permanently to the paper. The surface of the roller is coated with Teflon. This
ensures that toner does not adhere to the roller surface.