Ink jet printer - These printers put an image on paper using tiny jets of ink.

Laser Printer - It utilizes a laser beam to produce an image on a drum.

Static electricity is the principle behind the working of Laser printer.

Static electricity is simply an electrical charge that is built up on an insulated object, such as a balloon, our body, Plastic comb, etc. Since oppositely charged atoms are attracted to each other, objects with opposite static electricity fields cling together. A laser printer uses this phenomenon as a sort of “temporary glue”.

The core component of this system is the photoreceptor, typically a revolving drum or cylinder. This drum assembly is made up of highly photoconductive material that is discharged by light photons.

When the data is streamed from the computer, the electronic circuit activates the corona wire. The corona wire gives a positive charge to the drum.

As the drum revolves laser draws the image on the drum. Where the laser beam hits the drum, it erases positive charge and creates negative charge.

In this way, the laser "draws" the letters and images to be printed as a pattern of electrical charges - an electrostatic image.

The system can also work with the charges reversed -- that is, a positive electrostatic image on a negative background.

After the pattern is set, the printer coats the drum with positively charged toner -- a fine, black powder. Since it has a positive charge, the toner clings to the negative discharged areas of the drum, but not to the positively charged "background."

With the powder pattern affixed, the drum rolls over a sheet of paper, which is moving along a belt below.

Before the paper rolls under the drum, it is given a negative charge by the transfer corona wire (charged roller).

This charge is stronger than the negative charge of the electrostatic image, so the paper can pull the toner powder away. Since it is moving at the same speed as the drum, the paper picks up the image pattern exactly.

To keep the paper from clinging to the drum, it is discharged by the data corona wire immediately after picking up the toner.

Finally, the printer passes the paper through the fuser, a pair of heated rollers. As the paper passes through these rollers, the loose toner powder melts, fusing with the fibers in the paper.

The fuser rolls the paper to the output tray, and the page is printed. The fuser also heats up the paper itself, which is why pages are always hot when they come out of a laser printer or Photocopier.

So what keeps the paper from burning up? Mainly, speed -- the paper passes through the rollers so quickly that it doesn't get very hot.

After depositing toner on the paper, the drum surface passes the discharge lamp. This bright light exposes the entire photoreceptor surface, erasing the electrical image.

The drum surface then passes the charge corona wire, which reapplies the positive charge.