1. 4/16 Printers. Roll call Video (15 seconds) Lecture: –printers (general) –dot-matrix printers

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

3. Impact Printers Print head hammers the pins, etc. onto the paper through an inked ribbon. Image courtesy of http://www.brother.com

4. 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 http://www.ibilce.unesp.br/courseware/hf100/hf100m6f.htm

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

6. 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

7. 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.

8. 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).

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

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

11. 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 http://www.hp.com

12. 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 http://www.hp.com