4/16 Printers. Roll call Video (15 seconds) Lecture: –printers (general) –dot-matrix printers

Printers: general The “Hard Copy” Two Types: –Impact: dot-matrix daisy wheel –Non-Impact: inkjet laser thermal

Impact Printers Print head hammers the pins, etc. onto the paper through an inked ribbon. Image courtesy of

Daisy-wheel printers Impact printer. Like a typewriter –wheel with letters stamped on it –ink ribbon –wheel spins to correct letter, gets pounded onto the ink ribbon & onto the paper. Image courtesy of

Dot-Matrix Printers. Impact printer. Characters are formed from a matrix of dots. A vertical line of dots is stamped at one time.

Dot-Matrix Printers: the Print Head. Made of solenoids (electromagnets) and magnet-tipped pins. The solenoids, when charged, repel the magnets on the end of the pins. ADC

Dot-Matrix Printers: pins & a ribbon. The pins bang into a inked-soaked ribbon of cloth (or a inked- coated ribbon of plastic), and Bang the ribbon onto the paper.

Dot-Matrix Printers: the pins retreat. The pins return to the solenoids because of springs that keep them in place. The pins are made of tungsten (typically).

Dot-Matrix Printers: Advantages. Can print multiple forms at once (“carbon copy”) Reliable & Cheap. Low demand on the CPU.

Dot-Matrix Printers: Disadvantages. Can’t print transparencies Loud Slow (comparison)

Inkjet Printers. Shoot heated ink onto the paper. Cheapest, most common printers today. Faster than dot- matrix printers. Can print color. ADC Image courtesy of

Laser Printers Deposit toner onto the paper, then melt it to make it permanent. Cheaper by the day. Faster than Inkjets. Very quiet. ADC Image courtesy of