Printing

So, while scanning the page, each point is detected and marked as black and white or color, thereby forming a raster image. The transformation of the computer, i.e., the vector image to a raster performs using a raster grid, the so-called raster image processor (RIP). The input raster processor receives a set of commands PostScript, the page description language for printers developed by Adobe Systems in the mid-1980s. Images on the PostScript language for example, images created using special programs, containing instructions to lead the PostScript device with raster images for playback on the computer screen. Bitmap help the designer to get an idea of how laid out page with the illustration will look in print.
Prepared for replication publications can be printed on different devices, depending on the expected end result and the required number of prints. In particular for this purpose are widely used monochrome laser printers. The principle of operation they are similar to photocopiers in based on the static laser beam, the surface of the selenium drum. To electrified parts of the surface of the drum corresponding to the image, adheres the toner powder, which is then thermally transferred to the surface of the paper. The resolution of modern laser printers from 600 to 2400 dpi (eng. dots per inch means pixels per inch). Full printing is implemented using multiple technologies, providing different quality and cost of prints. Color laser printers allow you to get the cheapest copy, but the print is rougher, because the colors fade quickly. In addition, the printers that use the thermal transfer principle, are very slow because they need a pause after the passage of each of the four (the number of base colors) printheads - the wax should cool down.
Inkjet printers put on the paper image with the help of small droplets of liquid ink. The image quality obtained with the use of special paper of high density, can be wonderful, but the imprint is obtained expensive.
High quality desktop printing technology provides thermosublimation principle. Received on thermosublimation printers print very similar to the photos. The colored dots that comprise the printed image, in this case applied to paper by means of sublimation (transition of the gaseous phase into the solid) of the dye. Thermal sublimation provides a very accurate tones and semitones, intense color, and the surface of the imprint becomes glossy. The only disadvantage of the technology the cost per print is still higher than the inkjet printers.
In modern publishing and thermosublimation inkjet printers are used to output a small number of very high quality prints such as photos. If you want to print several dozen or hundreds of copies of a document, used laser printers. Finally, for large volumes of printing is used printing is offset printing, the quality of which can be quite high. To prepare a document for offset printing uses the process colour separation and photo output.