Adobe's approach left a gap in the market which Hewlett-Packard strove to fill with its own device independent-ish page description language based on its Printer Command Language, PCL, which first appeared in the 1970s. HP's marketing has … [Read more...]
PostScript Laser Printers
The situation changed dramatically in 1985 with Adobe's announcement of PostScript Level 1, based on Forth and arguably the first standard multi-platform device-independent page description language. PostScript describes pages in outline, vector … [Read more...]
Page Description Languages
Communication between a computer and a printer is very different today to what it was several years ago. Text was sent in ASCII along with simple character codes instructing bold, italic, condensed or enlarged type. Fonts consisted of those … [Read more...]
Environmental Issues
Unfortunately, the technology used in laser printers makes ozone an inherent by-product of the printing process. The level of emission depends on where and how a printer is kept. Areas with large concentrations of dust, small enclosed … [Read more...]
GDI Laser Technology
The alternative to laser printers which use languages such as PostScript and PCL are Windows GDI (Graphical Device Interface) bitmap printers. These use the PC to render pages before sending them as a bitmap for direct … [Read more...]
Laser printer Consumables
Most lasers use cartridge technology based on an organic photoconductive (OPC) drum, coated in light-sensitive material. During the lifetime of the printer, the drum needs to be periodically replaced as its surface wears out and print quality … [Read more...]
Color Laser Printers
Laser printers are usually monochrome devices, but as with most mono technologies, laser printing can be adapted to colour. It does this by using cyan, magenta and yellow in combination to produce the different printable colours. Four … [Read more...]
LED Laser Printers
LED (light-emitting diode) page printing - invented by Casio, championed by Oki and also used by Lexmark - was touted as the next big thing in laser printing in the mid-1990s. However, five years on - notwithstanding its environmental … [Read more...]
Laser Printer Operation
Where the image to be printed is communicated to it via a page description language, the printer's first job is to convert the instructions into a bitmap. This is done by the printer's internal processor, and the result is an image (in … [Read more...]
Laser Printer Communications
A laser printer needs to have all the information about a page in its memory before it can start printing. How an image is communicated from the PC's memory to a laser printer depends on the type of printer being used. The crudest … [Read more...]