David D. Thornburg, Associate Editor
Printers And Computers
Printer technology has advanced on so many fronts at once that it's hard to keep up to date. On one extreme is the continued push to ever-lower prices. The lowest-cost printers incorporate dot matrix mechanisms that either hammer ink onto paper through a ribbon, or that use thermal energy to transfer ink or induce color changes in special papers. These technologies have become so inexpensive that I recently saw a computer-controlled electronic typewriter that retailed for under $70.
Printers Smarter Than Their Computers
At the other extreme are the laser printers that combine xerographic copier technology with a computer-controlled laser beam to build up images on a photosensitive drum. The developed image is then transferred to a piece of paper at a resolution of 300 dots per inch. These printers are available at prices ranging from about $3,000 to $6,000 or so, and they often contain dedicated computers that can outperform the computer that is sending information to be printed. For example, the Apple LaserWriter (that I have connected to my Apple II as well as to my Macintosh) contains a 68000-based computer that can be programmed by the user through a Forth-like language called PostScript. The images created by this printer are exceptional in their quality.
It is interesting to note that, at both ends of the price spectrum, printers build images from an array of dots. The main difference between the extremes is in resolution, speed, and image quality. The market for various printers is sufficiently large that all kinds and prices of printers are enjoying a brisk business.
Considering the major impact that dot-matrix printer technologies have had on the personal computer industry, one wonders what will happen to the traditional printer that uses a daisy wheel or other mechanism to produce letter-quality type. These printers are still considered essential by most businesses, where low-resolution dot-matrix images are considered unacceptable. But letter-quality printers are comparatively expensive (at least the rugged ones are), and their price falls in the middle of the printer spectrum.
My concern for this technology is that it is being eroded from both ends. The low-cost printers are producing higher and higher quality images, and the laser printers are getting cheaper. Within the next few years the high-quality impact printer may become little more than a curiosity-used by people who, like me, prefer a fountain pen to a felt tip.
The difference between the dot-matrix and daisy-wheel printers is more than quality and price. The daisy-wheel printer is limited to printing text. Dot-matrix printers, on the other hand, can be used to prepare text or graphics, since both words and pictures can be formed from patterns of dots. This creative freedom of dot-matrix printers has other consequences. For example, if the resolution is high enough, text can be created in numerous styles (roman, italic, bold), type sizes, and fonts (character shapes).
Text Is Graphics
Text documents, as typesetters have known for centuries, are graphics documents as well. This realization is especially evident in laser printers, where the high resolution lets anyone do their own typesetting. Computer users who used to concern themselves with only spelling and grammar are now talking about leading (rhymes with bedding and refers to the blank space between lines of text), points (units of measurement equal to 1/72 of an inch), intercharacter justification (aligning columns of type), kerning (adjusting the spacing between two characters to be closer), ligatures (twin characters of type), and other terms that were rarely heard outside the walls of typesetting companies.
The most exciting aspect of low-priced laser printers is that small companies (and fortunate in dividuals) can be their own publishers. The economic justification for desktop publishing is easy to see. Suppose you are a software publisher who wants to create nicelooking manuals. The typesetting, proofreading, and editing of a 100-page manual can cost several thousand dollars and take several weeks. For a similar investment you can purchase a laser printer and, using documents written with your word processor, typeset the manual yourself in a day or two. The investment can pay for itself with the very first job.
You may think of the printer as a simple extension of the computer. It is far more than that-it is a tool that lets your creativity reach beyond the computer to touch others. Not a bad accomplishment for a mechanical contraption.
Dr. Thornburg's most recent product is Calliope, a nonlinear idea processor for the Apple IIe, IIc, and Macintosh computers. He welcomes letters from readers and can be reached in care of COMPUTE!. He has just published Unlocking Personal Creativity, a book on creative problemsolving that he wrote and typeset himself using the Apple LaserWriter.