The document describes the main components and functions of a laser printer. It explains that the laser unit generates a laser beam to write data onto the OPC drum. The main PCB receives data from the computer and controls printer functions, while the formatting PCB converts data for the laser unit. It then outlines the printing process, which involves cleaning, charging, writing, developing, transferring, and fusing toner onto paper.

1. LASER PRINTER
LASER UNIT PARTS

2. FUNCTION OF LASER UNIT: - Laser unit generates laser beam and writes the data on the OPC Drum.
Laser diode: - Generates laser beam.
Reflecting motor: - reflects laser beam towards focusing lens.
Focusing lens: - stretch’s the laser beam according to the size of OPC drum.
Mirror: - this is used for reflecting laser beam towards OPC DRUM.

3. MAIN PCB (LOGIC CARD)
This board is used for connecting printer with pc and receives data for printing. It also controls the
functioning of printer.
FORMATTING PCB: Receives the data from the main board and convert it into horizontal lines send it to
laser unit.

4. POWER SUPPLY
Function SUPPLIES power to the parts of printer according to the requirement.

5. PICK UP ROLLER
Used for loading of papers from the tray.
SPLITER
It’s used for splitting of papers as not to load multiple papers.
PLUNGER COIL
IT supports pick up roller when it receives signal to load paper for printing.

6. SCR (secondary corona roller)
This roller generates static charge which helps to transfer the toner from OPC Drum to paper.
FUSSER UNIT
 PRESSURE ROLLER: - press the paper against fusser roller.
 HEATING LAMP /STRIP: - Used for generating heat and to melt the toner.
 Teflon sleeve:-
This unit is used for fusing of toner with the paper, where the heaters generate heat up to 200degree
Celsius.

7. CARTRIDGE
OPC DRUM: - organic photo conductive material coated aluminum drum. This is main part of the printer
where image is written, processed and developed for printing.
PCR: - primary corona roller. This is used for charging OPC drum form -400V to -1600VDC.
DOCTOR BLADE: - This is used for controlling the level of toner on the magnetic roller.
MAGNETIC ROLLER: - This is used for attracting of toner in fresh toner cavity.
WIPER BLADE: - This removes the waste toner on OPC Drum which is left out after transferring.

8. LASER PRINTER PRINTING BLOCK DIAGRAM

9. PRINTING STAGES
 CLEANING
 CHARGING/CONDOTIONING
 WRITING/EXPOSER
 DEVELOPING/TONING
 TRANSFERRING
 FUSING
CLEANING

10. Here the waste toner which is left on OPC drum is cleaned by the wiper blade and stored in the waste
toner cavity. This process will help to get clean printing.
CHARGING/ CONDITINING
PCR charges the OPC drum from -400 to -1600vdc, which will help to get negative charge on the drum.
WRITING/EXPOSER
LASER unit generates laser beam and write the data on the OPC drum. Where the laser has at that
position it gets temporary magnetic properties, which help to attract toner from the magnetic roller.

11. DEVELOPING/ TONING
MAGNETIC ROLLER attracts the toner and doctor blade controls the level of toner after that OPC drum
attracts the toner where the laser beam has fallen on it.

12. TRANSFERRING
Image is transferred to the paper with the help of static charge generated by the SCR from the OPC
drum.

13. FUSING
As the paper comes in to the fuser unit, pressure roller presses the paper against fuser roller, at this
time toner on the paper will melt and fuse with the paper. Heater temperature will be up to 200celsies.

14. TROUBLESHOOTING