Question

What is the main property of organic photoconductive material that is coated in the drum of a laser printer?

Hint:

Because organic photoconductor (OPC) drums are highly sensitive to light, they can degrade if exposed to direct sunlight or ambient room light for extended periods during maintenance. Always store them in a dark, dust-free cover when servicing a printer.

Answer 1

Step 1: Understanding Laser Printer Operation:
A laser printer uses an electrostatic process to transfer toner (ink powder) onto paper. The heart of this system is a rotating metal drum coated with a thin layer of an organic photoconductive material (OPC).

Step 2: Identifying the Main Property:
The key property of organic photoconductive materials is Photoconductivity.

• In the Dark: The material acts as an excellent electrical insulator. It holds a high, uniform positive or negative electrostatic charge placed on its surface by a corona wire.
• In the Light: When hit by a focused laser beam, the material's electrical resistance drops dramatically, turning it into an electrical conductor. This allows the electrostatic charge in the exposed areas to bleed off to the grounded metal drum below.

Step 3: Image Formation:
This selective discharging process leaves behind a latent electrostatic charge image on the drum, which then attracts the charged toner particles for transfer onto the paper.