What is laser printing?

What is laser printing?

IBM introduced the first laser printer in 1975 for use with its mainframe computers. In 1984, Hewlett-Packard revolutionized laser-printing technology with its first Laser Jet, a compact, fast, and reliable printer that personal computer users could afford. Since then, laser printers have decreased further in price and increased in quality. Hewlett Packard continues to be the leading manufacturer with competitors including Lexmark, canon, and Xerox. The laser printer is different from an inkjet printer in a number of ways. The toner or ink in a laser printer is dry. In an inkjet, it is wet. Over time, an inkjet printer is about ten times more expensive to operate than a laser printer because ink needs replenishing more frequently. The printed paper from an inkjet printer will smear if wet, but a laser-printed document will not Both types of printer operate quietly and allow fonts to be added by using font cartridges or installing soft fonts. If your printing needs are minimal, an inkjet printer is sufficient. But if your printing volume is high, consider buying a laser printer.

Laser Printer Definition

A laser printer is a printer that uses a focused beam or light to transfer text and images onto paper. Though contrary to popular belief, the laser does not actually burn the images onto the paper. Instead, as paper passes through the printer, the laser beam fires at the surface of a cylindrical drum called a photoreceptor. This drum has an electrical charge (typically positive), that is reversed in areas where the laser beam hits it. By reversing the charge in certain areas of the drum, the laser beam can print patterns (such as text and pictures) onto the photoreceptor.

Once the pattern has been created on the drum, it is coated with toner from a toner cartridge. The toner is black in most cartridges, but may be cyan, magenta, and yellow in color laser printers. The positively charged toner clings to areas of the drum that have been negatively charged by the laser. When the paper passes through the printer, the drum is given a strong negative charge, which allows the toner to transfer and stick to the paper. The result is a clean copy of the image written on the paper.

Because laser printers do not use ink, they have less image smearing problems than inkjet printers and are able to print pages faster. While laser printers and toner cartridges typically cost more than inkjet printers and ink cartridges, most laser toner cartridges last several times longer than ink cartridges, which makes their cost per page about equal. For this reason, businesses tend to use laser printers, while consumers are more likely to use inkjet printers. Laser printers typically have a resolution of 600 dpi (dots per inch) or higher.

Following are important features

Resolution

The standard resolution in most laser printers today is 600 dots-per-inch. This resolution is sufficient for normal everyday printing including small desktop publishing jobs. A high-end production printer might have a resolution of 2400 dpi. Some laser printers still use a resolution of 300 dpi. This resolution can cause jagged lines to appear on the outer edge of an image. Hewlett Packard created RET to correct this. RET inserts smaller dots at the edges of lines and to smooth the rough edges. RET does not improve the resolution, but the document looks better. If you purchase a printer with 300 dpi, make sure it has RET.

Handling

Paper handling is important when shopping for a laser printer. Most laser printers use letter-size, cut-sheet paper. High-end production printers use continuous sheet paper. Laser printers can print on transparencies, adhesive labels, and lightweight cards. A laser printer with duplex printing can print on one side of the paper, turn the paper over, and print on the other side. Most laser printers, however, use simple printing with manual duplex printing. Manual duplex printing is achieved by changing the print options in the printer's properties or printing one side and taking that same paper and reinserting it into the printer to print on the other side.

FPOT and warm-up time

A final consideration in purchasing a printer is FPOT (first paper out time) and warm-up time. When a laser printer receives data from the computer to print, it takes 5 to 30 seconds to prepare the printer to print a new job. 

Languages

Printer Control Language ( PCL ) is the standard printer language for Hewlett Packard and most other laser printers. PCL is used for printing letters, database printouts, spreadsheets, and simple graphics. Postscript printers are used with desktop publishing software and drawing packages. Postscript printers are the norm for Apple Macintosh printers. A laser printer that comes with Postscript installed is more expensive. A laser printer that uses PCL can be upgraded to Postscript by installing a software driver provided by the manufacturer of the laser printer. 

Capacity and speed

Personal laser printers are sufficient for printing an average of 200 pages per week. They can print up to eight ppm (pages per minute). A work-group printer is needed if an average of 1000 pages per week is needed. Production printers are needed for printing 50,000 or more pages per week.They can print 24 hours a day, seven days a week.

Performance

As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1984, the HP LaserJet sold for $3500, had trouble with even small, low resolution graphics, and weighed 32 kg (71 lb). As of 2016, low-end monochrome laser printers can sell for less than $75. These printers tend to lack onboard processing and rely on the host computer to generate a raster image, but outperform the 1984 LaserJet in nearly all situations.

Laser printer speed can vary widely, and depends on many factors, including the graphic intensity of the job being processed. The fastest models can print over 200 monochrome pages per minute (12,000 pages per hour). The fastest color laser printers can print over 100 pages per minute (6000 pages per hour). Very high-speed laser printers are used for mass mailings of personalized documents, such as credit card or utility bills, and are competing with lithography in some commercial applications.

The cost of this technology depends on a combination of factors, including the cost of paper, toner, drum replacement, as well as the replacement of other items such as the fuser assembly and transfer assembly. Often printers with soft plastic drums can have a very high cost of ownership that does not become apparent until the drum requires replacement.

Duplex printing (printing on both sides of the paper) can halve paper costs and reduce filing volumes. Formerly only available on high-end printers, duplexers are now common on mid-range office printers, though not all printers can accommodate a duplexing unit. Duplexing can also give a slower page-printing speed, because of the longer paper path.

In a commercial environment such as an office, it is becoming increasingly common for businesses to use external software that increases the performance and efficiency of laser printers in the workplace. Software can be used to set rules dictating how employees interact with printers, such as setting limits on how many pages can be printed per day, limiting usage of color ink, and flagging jobs that appear to be wasteful.

What is laser printing?