Index

Printer information and utilities

    General information

    A often asked question is should I select an inkjet or laser printer.The answer depends on how much money you are willing to spend and your printing needs.Generally speaking, Inkjet printers are slower than Laser printers but have a lower price tag. Most Inkjet printers allow for color printing while reasonably priced Laser printers do not. If you don't have a need for high volume printing(a few pages a day on the average), an color Inkjet printer is a good choice.Laser printers are generally more expensive and faster than Inkjet printers. Printing in black and white are more crisp(better clarity) on the Laser printer. Laser printers use toner based technology(like the toner you put in the copier). If you are a business with high volume printing needs(about 1000 pages a month or more), you should look for a laser printer.Laser printers are better equipped for high volume printing.

    Printer controlling languages

    There are many ways to describe what a page to be printed should look like. Each different method of description is called a "Page Description Language" (PDL).In the dark ages before the advent of laser printers, PDLs were simple extensions to text files that controlled the special features of a particular printer.These PDLs were tailored to a particular type of printer, and could only describe pages that the target printer was capable of printing.Nowadays there are fortunately standardized printing languages like PCL and Postscript.

      PLC

      Printer control language (PCL) was released over 15 years ago by Hewlett-Packard as a simpler, faster and less expensive alternative to Postscript based laser printers. Low-cost LaserJet and DeskJet printers from Hewlett-Packard speak also PCL. PCL has fewer features than Postscript. Fewer features means simplicity, the biggest reason most workgroup printing is PCL and most printers sold today are PCL-based. PCL was created from the beginning as a simple, open language. HP's business is printers, not proprietary page description languages. The result is that there are many vendors in the PCL business making printers, software which enhances print jobs, viewers, and more. The PCL command is recognized by the LaserJet by the presence of an Escape character (unprintable control character, ASCII value 27). The remaining characters are almost always printing characters, with the first selecting a group of related commands. Writing PCL code is somewhat like programming into a black hole. It is easy to write Escape sequences that appear to do something, but that don't actually do anything. The printer politely ignores any syntax errors without telling you about them.

      Postscript

      PostScript is a page description programming language. It is perhaps the most versatile and loved language for printers, being used in printers world-wide. It is capable of drawing to computer screens and any kind of drawing device. PostScript was developed at Xerox at 1982. PostScript allows a page to be arbitraily complicated. A Page may be so complicated that the printer must pause the printing process while it interperts the PostScript commands. PostScript is not tied to any particular printer, or any particular manufacturer. PostScript page descriptions are not tied to any particular resolution printer. PostScript is designed to allow the application program to easily communicate with the printer (=send printed page to printer). Postscript langauge most often used as laser printer controlling laguager, but is a complete programming language. Actually PostScript is a combinations of three things: A Page Description Language, A Printer Control Language and A Programming Language. PostScript is interpreted, stack based and has latent typing. It somewhat resembles the computer language FORTH. PostScript programs are usually documents meant to be printed that have been generated by a program written in some compiled language. PostScript is not an extension to simple text files. A simple text file must be converted to PostScript before being printed (many systems can do this automatically). The original releaqse of PostScript is now called "Level 1". Many additions and enhancements have been made which bring the language to "Level 2".

        Epson printer controlling commands

        Epson MX and FX series of matrix printers were popular many years ago. For this reason the controlling codes they used became popular and were emulated by very many other manufacturers. Epson emulation was once very important, but it is not much used nowadays. Generally Eprosn printers take in normal ASCII data text. It prints out the received text every time it send receiver return and carriage return commands. Also form feed and similar basic things are done with special control characters in ASCII standard. This means to print an ASCII document, you can just copy it to the printer port. Many Eprosn printers can do also other things than just printing that normal text with default font. Many printers had different fonts, character enhancements (like bold, italic ets.), different line spacing and some even different colors.All of the Epson's advanced capabilities are activated by sending a specific control code from the computer to the printer. The control codes are alphanumeric symbols usually preceded by the [ESC] character. The codes simply turn particular functions on and off. This allowes that any print command can be sent to the printer prior to loading the printing program. That command remains "on" until the printer is reset or modifed by the commands the software sends to the printer. You can usually find these codes in the appendix to the Epson manual.

      HPGL

      HPGL is abbreviation of Hewlett-Packard Graphics Language. It is a set of commands for controlling plotters and printers. HPGL language is used to describe vector graphics as plotter use it. HPGL is presented to the plotter as quite simple ASCII based language which has few commands for pen control and parameters for them. HPGL is part of Hewlett-Packard's PCL Level 5 page description language.

        Other controllign languages

        There are also many other printer controlling languages. Usually every printer manufacturer has some of their own controlling language or language extensions available for their printers. Nowadays common "Windows printers" use usually a proprietary communication language between the printer and PC. This communication usually sends the printed data in some bitmap like format from the printer driver to the printer. The printer driver communicates with the application program, generated the bitmap of data to be printed and sends it to printer. Some printers nowadays can accept also PDF documents as printer controlling language.

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