Printers are output devices that write information (characters or dots) on paper.
The printers have two parts mechanics and other electronics while the printers can be divided into impact or non-impact printers.
With impact printers are noisy, but can make multiple copies using special paper (continuous paper with or without side holes). Among her are the wheel printers, Ball, Daisy, cylinder, chain, steel strap and matrix.
The non-impact printers form characters without mechanical shock and other physical principles used to transfer the image to paper or characters. In this group are thermal printers, inkjet, magnetic and electronic transfers and Laser.
Printers can print by character, by lines or pages .
Character printers , printing done by a head you type each line character by character (can be unidirectional or bidirectional). The speed of such printers is 10 to 400 characters per second.
The printer fonts are printed by character wheel, ball, daisy, matrix, thermal and inkjet.
Line printers , printing simultaneously perform all or several characters corresponding to one print line. They operate with a buffer, when filled, the mechanical operation of printing of characters may be performed in any order.
Print speed is between 300 to 2000 lines per minute, are about 400-2600 characters per second. Some printers are thermal lines, drum, bar, strip and electrostatic transfer.
Page printers , make printing the page as a whole, in this group have the laser and some inkjet models. Such printers are in (ATMs, cash registers, receipts), the characters are formed by of a matrix of dots (needles) ranging from 7 x 5 to 24 x24 needles, said needles are triggered by electromagnets.
Needle printers are very resistant and used in very hostile environments, eg in dusty places (warehouses, workshops, factories).
If you want to print and copy documents with original printer type is ideal for this role. The downside of these printers can print only one color (black) and if you break one of the needles, the characters printed on paper is very difficult to interpret.
The way to print on paper is simple, place a black ribbon between the paper and the head with needles. When the electromagnet acts on the needle and expelled outward forming a character, leaving the bore ink ribbon impregnated paper.
After printing the character, the ink film is driven by rollers so you can return to the needles hit the ink film and thus no excess spoil or pierce the fabric containing the tape reel.
Another printer widespread both in our homes and in businesses is the inkjet .
The physical operation is to emit a jet of ionized ink droplets, which in its path is deflected by electrodes which are at a fixed potential (+ – 3KV).The character is formed with the ink strikes the paper.
In inkjet printers for color, one of the most important factors is the porosity of the paper, the color we perceive is not generated by a light source, but which reflects the role, not absorbed by the printed ink , so we have to use subtractive colors.
For print quality, we need 4 different colors: one for black (K Color Black), and the other three: blue (Color Cyan C), yellow (color and Yellow) and red (Color Magenta M). The entire assembly is usually referred colors CYMK.
The inkjet printers at household level are very economical, but where do the printer manufacturers in August is in the ink cartridges. The prices of these cartridges many of them cost more than a new printer.
In order to choose the brand of printer for our house, the most important is the separation of colors in different cartridges, thus buy only the desired color as indicated by the printer to be exhausted.
Marks with 4 cartridges, one black and the other three of each of the colors are Epson and Canon, the other manufacturers like HP and LEXMARK placed the three colors in one cartridge and its price is very high compared to acquiring a single color cartridge.
Last but not least are the laser printers , both white and black as the color.
Laser printers have a high printing speed, low price and use plain paper A4 or A3. The printed page is transferred to paper by contact from a drum containing a toner image impregnated (coal dust).
The drum is covered with a photoconductive material (silicon) remains dark electric charge is discharged and lit.
The electric image on the drum is formed by impinging thereon a laser beam which sweeps the generatrices of the drum. Each generator usually corresponds to a column of dots on the page to print.
Is printed along and crosswise. Color laser printers use four toner deposits corresponding to the set CYMK, producing the variety of colors by mixing. If you want to print a lot of information quickly and cost laser printers is the best choice.