|This article does not cite any references or sources. (July 2009)|
A page printer is a computer printer – and a computer by itself – which processes and prints a whole page at a time (contrary to printers which print line for line, like e.g. line printers and dot-matrix printers). It is connected to one or more PCs, servers, mobile phones or other host computers. Page printers are often called “laser printers” – but even if virtual all laser printers are page printers, other page printing technologies do also exist.
The page printer was jointly developed (circa 1900) and patented in 1924 by Sterling Morton and Howard Krum..
Necessary for page printing are:
- A printing engine.
- memory to process and build up a page. The printer may have its own memory, and/or utilize the host computer’s memory.
- A page description language (PDL), with commands which tell the printer how to build up the page, and print it. Popular PDLs are PCL (Printer Command Language) from Hewlett-Packard, PostScript from Adobe Systems and PostScript clones, and Windows’ GDI (Graphics Device Interface).
- A raster image processor (RIP), i.e. a processor to compute the page layout. Sometimes, this processing is done by the host computer. By the other way, big printers used for fast and high-volume network printing, may have powerful processors to serve a lot of users.
- A printer driver, i.e. a program (a device driver) which converts the computer’s information about the page into a sort of codes which are understandable for the printer with the actual PDL. Printer drivers are included in the operating systems, follow the printers as CDs or DVDs, and/or are downloaded from the printer manufacturer’s home page or from independende web sites.
- A connection (interface) to the host computer. Popular interfaces today are e.g. USB and Ethernet. Many older printers do also have a parallel (Centroinix) interface.
Page printing technologies
There are several page printing technologies, e.g.:
- Laser printers. Most page printers are laser printers.
- LED printers, which use Light-emitting diodes instead of a laser beam, but are otherwise very similar to laser printers.
- Melting wax (“phaser”) printers, where solid ink is heated to the melting point and is applied on the print medium where it immediately freezes.
- Dye-sublimation printers, where a solid ink (dye) is converted to a gaseous state (sublimation) and applied on the print medium, where it immediately freezes.
- Resolution, 600 or 1200 dpi (dots per inch) in most modern page printers, often with a sort of resolution enhancement or antiliasing to smooth uneven lines. Higher resolutions do occur, too. Before about 1992, the year Hewlett-Packard made the LaserJet 4, built around a Canon engine, most page printers had only 300 dpi, which made visible jagged lines and relatively poor image quality.
- Engine speed. Generally, page printers have been faster since Canon in 1984 made the first “small” laser printers which could stay on a (sturdy) desktop – only 32 kg, and with an engine speed of 8 pages per minute (ppm). Today, even the smallest pages printers are able to print 15–20 ppm, and the biggest may print above 1000 ppm.
- Processing power. Usually, bigger network printers do have more powerful processors than small personal ones.
- Size, from personal page printers at 6–10 kg to high-volume production printers which may not be installed by one man.
- Costs, both costs of the printer and the operating costs. Generally, the bigger and more expensive printers have lower operating costs than the small and cheap ones.
- Paper-handling facilities for folding, stapling, etc., especially for the bigger printers.
- Colour printing capability, usually with four toner cartridges, wax patrons etc. – one each for the colours cyan, magenta, yellow, and black (hence CMYK, Cyan, Magenta, Yellow, blacK). Some ink jet printers may have more than four cartridges (e.g. light cyan and light magenta in addition to the foure others), but this do rarely occur in page printers.
- Multi-function like copying and scanning.
- Media handling: Most page printers accept paper, transparencies, envelopes, labels etc. made for laser printing in formats up to letter and A4. Some printers may also be used on other media types like bigger formats (which do require bigger printers) and heavier paper qualities. There are also page printers for specialized media.
- Energy consumption, noise, etc. Some page printers are too noisy to stay in the near vicinity of the users, even if page printers are more silent than the old line printers and other impact printers.