what is printer and its types

 

Printer is a device that prints text and image on paper. The most common devices that use printer technology are copiers, photocopiers, and fax machines. Printers can be classified into three types: impact printers, thermal transfer printers, and inkjet printers."

A printer is a device that makes printed documents using an arrangement of nozzles called printheads which produce small drops of liquid (called "droplets") onto paper feedstock to create an image or text using ink as the medium. A typical modern printer has at least one print head for each of the primary colors—cyan, magenta, yellow, and black ("CMYK" for short). Other possible color print heads have been used in rarer cases. The print heads are normally small ink jets, electrostatic devices, or laser beams (in the case of optical printing).[1]

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In impact printers an ink mist is formed on a spinning cylinder which is then deflected by a hammer onto paper. In thermal transfer printers there is a ribbon upon which hair-like fibers are printed and then melted onto paper. With inkjet Printers ink is "sucked" from a reservoir by one or more print head(s) onto the paper. The most common technology uses a piezoelectric crystal that when compressed causes jets of ink to be released.

A proof (also called "letter-quality") printer is a printer that creates new pages of printable paper by printing letters on the same paper that was used to print the original page. The technique of printing letters is known as letterpress printing, and was perfected by Gutenberg in 1440 and made popular by Johannes Petrus Ramus in 1512 with his book on letterpress printing. Proof printers use specially coated paper which becomes coated with ink when exposed to high pressures; the phrase "to go off proof" means that it has been printed again to check for errors.

 

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The earliest known printers were stone carvings used for printing religious or political announcements in Sumer, about 3500 BC. A printer is a person or company engaged in the activity of printing, in which it is customary to use the same blocks for all printings; hence, the printer is also called a block maker. In 15th century Europe, Gutenberg's printing press made books widely available and more affordable. Printing was not quite widespread by the end of the 17th century, but it was still fully developed with its own specialized workers and trades.

Much later, around 1770, mimeograph machines were invented. These could be used by individuals to make their own prints without having to pay a print shop. In the late 19th century, the steam-powered cylinder machine was invented. The first moving images were created with this equipment. The need for much cheaper and faster printing presses led to the invention of phototelegraphy in 1862 by Charles Wheatstone, who began using it to send telegrams over long distances. The first carbon print (not called a photocopy) was made in 1873 by Charles de La Tour using an image taken from a mirror image glass card, which paved the way to modern photography.