1. Introduction to Computers
Printer Types

2. Printer Types
Printers were once the most important device in an office. Before cloud computing, home computers, tablets and smart phones made digital information consistently available, everything done in a business setting needed to be recorded physically
Since printers have been important for such a long time there are many different printer technologies available, all with different uses, different strengths and weaknesses and different techniques
This lesson is designed to introduce these different printers to the class
Since it may be hard to visualize, we’ll have a video at the end of this lecture to show how these printers work

3. Dot Matrix Printers
The first and oldest type is called an impact or dot matrix printer
A dot matrix printer is an impact printer that transfers characters by striking a pattern through an inked ribbon and onto paper
There are four critical components in a dot matrix printer
The first is the print head. The print head is relatively small in a dot matrix printer. It looks like a kind of square block with a series of pins (9, 18 or 24). The more pins, the higher the quality
In addition to the print head we also have a component called the platen. It's a circular component like a big cylinder and it's black in color. Its job is to hold the paper in place and serve as a back for the print head as it hits the paper
An impact printer also has a ribbon that contains the ink to be transferred onto the paper
The last component is called the tractor feed. The tractor feed is used to draw continuous speed paper up through the printer.

4. How a Dot Matrix Printer Works
The print head has a series of pins, and each of these pins is actually retracted inside the print head with a spring that keeps them pulled inside of the print head.
To print, the printer sends electrical current in a pattern for the pins. The current goes to a solenoid that receives the current and fires the pins out to match the current’s location. They hit the ribbon up against the paper and leave an imprint on the paper. By using a variety of patterns we can create different letters.
Using only nine pins means that the letters don't have great quality. The more pins you have in the print head the better the print quality.

5. Dot Matrix Printer Pros and Cons
Dot matrix printers are legacy devices, but still see use
One of the key reasons is the fact that dot matrix printers can do one thing that most printers just can't do - they can print duplicate or triplicate forms
With the dot matrix printer we actually have a physical impact so you can put carbon copies through the dot matrix printer and have them print out. This is useful for things like rental contracts, receipts and anything else that require multiple copies
Dot matrix printers tend to give low quality prints and tend to be slow
The print head can become dangerously hot due to pin friction
Dot matrix printers can be loud because printing takes place by pins physically striking the ink ribbon, paper, and the platen (a metal plate behind the paper)

6. Thermal Printers
A thermal printer is a non-impact printer that uses heat to cause a reaction on specially treated paper
Instead of using ribbon or ink or melted ink sticks they use special paper that reacts to heat
Monochrome thermal paper is chemically treated to darken where heated. This type of printer is used often for creating receipts
Color thermal paper is chemically treated to absorb color from a ribbon where heated
The color system used by thermal printers is CMYK (cyan, magenta, yellow, and black), and the paper must make one pass for each application of a different color

7. Thermal Paper Pros and Cons
Thermal printers are another older technology, but they see use still, mostly in label makers, receipt printers and fax machines
Monochromatic printers tend to be very reliable and precise, the paper dries almost instantly, and there is no ink to buy
One issue with monochromatic thermal printers is that the paper is expensive and can be hard to use
Color thermal printers are very expensive, high quality, and operate quietly

8. Inkjet Printers
Inkjet printers are quiet non-impact printers with ink stored in a reservoir. Bubble jet printers are the most popular form of inkjet printers.
The ink reservoir is in a disposable cartridge that includes the printing mechanism
Bubble jet printers print by heating the ink and squirting it through tiny nozzles in the print head and onto the paper
The crispness of an inkjet printer's image is usually rated as dots per inch or dpi. Inkjets range from 150 to over 1400 dpi, and a new generation of inkjet printers produce photo-quality printouts when used with photo-quality paper
Photo-quality inkjet printers mix up to 16 drops of ink to form a single dot of color on the page

9. How an Inkjet Works
Inkjet printers feed single cut sheets of paper, from a feed tray, by clamping them between rollers and advancing them one print line at a time
The ink cartridges sit inside a carriage and a belt is used to move the carriage across the paper. The print head in an inkjet printer is similar to a dot matrix printer, except instead of having pins inside that come out and strike a ribbon we have a whole bunch of ink nozzles
To fire nozzles, an electrical current is applied to each of these nozzles and ink inside of the nozzle boils and creates an air bubble. When that happens, it shoots a jet of ink and makes a dot on the piece of paper. By varying the current and applying it to different nozzles in the print head, we're able to create different patterns on the pape
If you have a duplexing assembly the printer will feed the paper through the printer twice, printing on both sides of the paper

10. Inkjet Pros and Cons
Inkjet printers create high quality output and they're fairly inexpensive
Inkjet printers have one weakness, however - most of the electronic circuitry that makes up the printer is not actually in the printer itself. When you use up the ink in the ink reservoir you have to get a new ink cartridge, and it may be as much or if not more than the printer itself. That's because most of the electronic circuitry that makes up the inkjet printer is actually in the print head, so when you have to change the ink reservoir, you are buying a new component that makes up the inkjet printer
This is why when you install a new cartridge, you should use the printer calibration utility to calibrate the inkjet so that all the ink cartridges are aligned. This ensure that the final output is properly represented on the paper

11. Specialty Printers - Dye Sublimation
A dye sublimation printer is a non-impact printer that uses film-embedded dye
In dye sublimation printing, the colors are not laid down as individual dots. Inside of a dye sublimation printer is a long roll of semitransparent film and that film is made up of individual sheets stuck end to end of different colors (cyan, magenta, yellow, and black), and the print head uses heat to transfer the ink from these films onto the paper
The print head heats and passes over the film, causing the dye to vaporize and soak into the film paper
Dye sublimation printing prints in transitioning colors rather than pixels and produces photographic quality images
A dye sublimation printer allows you to print photo lab-quality pictures. The key benefit is that they provide a smooth blending of colors, which is hard to achieve with other types of printers
In addition, it's also less vulnerable to fading, ink bleed and distortion over time

12. Specialty Printers - Solid Ink
Solid ink printers melt ink onto the print head (which is as wide as the paper)
The head jets the melted ink onto the paper as the paper passes by on the print drum (similar to the laser printing process)
The head takes as long as 15 minutes to heat prior to printing, but solid ink printers offer the following advantages: Simple design, Excellent print quality, Easy set up and maintenance
A solid ink printer creates smaller, more uniform dots than a dot matrix or inkjet printer and instead of using a ribbon or a liquid ink, a solid ink printer uses solid sticks of ink that are inserted inside the printer
In a solid ink printer, multiple solid ink sticks are melted within the print head and are jetted onto a drum. As the ink is jetted onto the drum it rotates to cover the whole drum. After the ink is melted onto the drum a piece of paper is then drawn from a paper tray and is rotated around the drum or drawn across the drum and as it does so the melted ink from the drum is transferred onto the piece of paper. The ink then cools and adheres itself to the paper
Solid ink printers create some of the highest quality output you can get outside of a regular printing process

13. Printer Videos Overview- https://www.youtube.com/watch?v=JEVurb1uVFA
Inkjet -
Laserjet -