How a laser printer works

How a laser printer works

How a beam of light creates crisp text and images in a laser printer.

A laser printer is a computer printer that quickly produces good quality text and graphics on blank paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.

Laser Printers Vs Inkjet Printer
Laser printer advantages:
Speed: A laser printer can turn out pages faster than an inkjet printer.
Low cost: Over time, toner costs for a laser printer will total far less per page than refilling/replacing inkjet printer cartridges.
Quiet operation: A laser printer is generally quieter than low-cost inkjet printers.
Best-quality text: No inkjet printer-no matter how much you pay for it-will ever turn out black text and line graphics as crisp as a laser printer.

Inkjet printer advantages:
Versatility: A colour inkjet can print on many types of media, including craft paper, T-shirt transfers and even printable CD/DVD discs.
Smaller size: This saves you space on your desktop.
Larger paper sizes: If you spend more, you can add a large-format inkjet printer to your system that can print 11-x-17-inch or larger items.

Printer's Past
1938: Chester Carlson invents a dry printing process called electrophotography, now called xerography.
1953: The first highspeed printer is developed by Remington-Rand.
1969:The original laser printer, called EARS, developed at the Xerox Palo Alto Research Center.
1976: The inkjet printer is invented.
1992: Hewlett-Packard releases the popular LaserJet 4, the first 600 x 600 dots per inch resolution laser printer.

1.  PC sends command to printer for a print job. Controller circuitry (inside printer) queue up and translate printing data; a raster image processor (RIP) converts images and text into a virtual matrix of tiny dots.

2.  Controller circuitry applies a positive electrical charge to the drum unit. Afterwards, the laser system 'writes' the page image onto the drum with a negative charge, creating an electric "virtual negative" of the image.

3.  The drum unit rotates, and as the image is written on it, it picks up the toner, the laser printer equivalent of ink. The toner is positively charged, and so it sticks to the image that the laser drew. The paper presses against the drum, and receives the toner image.

4.  When the paper first picks up the toner, the image is not set. The toner is a dry, dusty material, and the electric charge cannot hold it strongly to the paper. In order to make the image permanent, the paper runs through the fuser, which heats it, and melts the toner onto the page. The paper exits the printer, and you have your print out.

Courtesy: Gadgets and Gizmos