PC Hardware

Printer Basics

Printers have virtually replaced the typewriter in the contemporary office. The simplest printers are designed for the bargain-seeking home user, while the most complex are designed for production use, producing over 60 pages per minute and offering features like collating, stapling, and internal two-sided printing.

When evaluating printers, you should keep the following issues in mind:

  • Printer resolution: Resolution is usually measured in dots per inch (dpi). This indicates the number of vertical and horizontal dots that can be printed; the higher the resolution, the better the print quality.

  • Speed: This is usually given in pages printed per minute, where the page consists of plain text with five percent of the printable page covered in ink or toner.

  • Graphics and printer-language support: If the device is used to print graphics, it should support one or more of the popular printer languages, such as Adobe PostScript and Hewlett Packard's LaserJet PCL (Printer Control Language).

  • Paper capacity: The number and types of paper trays available, the number of pages that can be placed in them, and the sizes of pages that can be printed all vary widely among printers. Some smaller units hold as few as 10 sheets, while high-volume network printers hold several reams in different sizes. Some printers can also be set to automatically choose which tray to use based on the type of paper best suited for a job.

  • Duty Cycle: This is the number of sheets of paper the printer is rated to print per month. It is based on a plain-text page with five percent coverage and does not include graphics.

  • Printer memory: Laser printers that will be used to print complex graphics and full-color images require larger amounts of memory than those which print simple text only. In many cases, this memory can be added as an option.

  • Cost of paper: Will a printer require special paper? Some printers must use special paper to produce high-quality (photo-quality) images or even good text. Some paper stocks are too porous for ink-jet printers and will cause the ink to smear or distort, causing a blurred image.

  • Cost of consumables: When comparing the cost of various printers, be sure to calculate and compare the total cost per page for printing, rather than just the cost of a replacement ink or toner cartridge.

Common Printer Terms

You should familiarize yourself with these basic terms used with printer communication:

  • ASCII (American Standard Code for Information Interchange): A standard code representing characters as numbers, used by most computers and printers.

  • Font: A collection of characters and numbers in a given size, usually expressed in style name and size, and expressed in points (pts.)-for example, Times Roman 10 pt. bold (One point equals 1/72 inch.) Although many people think that bold and italic are variations of the same font, technically they are different fonts. Some printers are sold with limited fonts, such as bold only or no-bold varieties of the typefaces.

  • LPT (Line Printer Terminal) Port: Term that describes parallel printer ports on a computer.

  • PCL: Hewlett-Packard's printer-control language for printers.

  • PostScript: The most common page-description language (PDL). A method of describing the contents of a page as scalable elements, rather than bitmapped pixels on the page. The printer is sent a plain ASCII file containing the PostScript program; the PostScript interpreter in the printer makes the conversion from scale to bitmap at print time.

  • Resolution Enhancement: Technology that improves the appearance of images and other forms of graphics by using such techniques as modifying tonal ranges, improving halftone placement, and smoothing the jagged edges of curves.

  • Portrait: The vertical orientation of printing on a piece of paper so that the text or image is printed across the 8.5-inch width of the paper.

  • Landscape: The horizontal orientation of printing on a piece of paper so that the text or image is printed across the 11-inch width of the paper.

  • Duplexing: The ability to print on both sides of a page. This cuts operating costs and allows users to create two-sided documents quickly.