Although many offices have tried to go completely paperless, we have yet to develop a perfect replacement for the printed word. Until we do, the office printer will continue to be a critical business machine, and IT support techs will have to support them.

So to help you hone your printer skills, we offered a quick Printer Pop Quiz that more than 1,600 of our members took. Did most of them know what a laser printer’s transfer corona wire does, or how many nozzles a thermal bubble inkjet has? Let’s find out.


Transfer corona wire

Figure A

The correct answer is: Charges the sheet of paper, which then attracts the toner particles from the drum, and 57 percent of the members who took the quiz got it right, as shown in Figure A. The laser printing process is based primarily on static electricity. As the printer’s drum (shown in Figure B) spins, it is given an electrical charge, either by a charge corona wire or by components within the drum itself. This charge can be either negative or positive depending on the type and model of printer.

Figure B
The electrophotographic drum has a conductive surface.

A laser then draws the text or images to be printed on the drum. The areas of the drum on which the laser shines are subsequently discharged. The printer then coats the drum with toner. Because the toner carries the same charge as drum, it only sticks to the discharged areas on which the laser was shown.

As the drum continues to turn, a sheet of paper passes underneath. Before the paper gets to the drum however, it passes by the transfer corona wire, which charges the sheet of paper with a charge opposite to that of the toner. This charge is stronger than the charge holding the toner to the drum, which causes the paper to attract the toner. The paper is then fed through the fuser assembly, which melts the toner to the paper. Meanwhile, the drum surface passes by a discharge lamp that neutralizes its electric charge. The drum is then ready to begin the printing process again.

Fuser assembly

Figure C

The correct answer is: Fuser assembly and an exceptional 84 percent of those who took the quiz knew this answer, as shown in Figure C. Looks like most of you won’t be burning your fingers.

Figure D

Again referencing the description of the printing process given above, the fuser (Figure D) melts the toner to the paper, reaching temperatures around 350 degrees Fahrenheit. The paper’s speed keeps it from burning as it passes through the fuser assembly.

Piezoelectric print heads

Figure E

The correct answer is: Inkjet printers, but only 50 percent of our quiz takers knew this answer, as shown in Figure E. Inkjet printers use two primary methods of applying the ink to the paper: thermal bubble and piezoelectric.

Both Canon and Hewlett Packard use thermal bubble technology commonly referred to as “bubble jet.” Within the print head of a thermal bubble printer, tiny heating elements heat the ink creating a small air bubble. As the bubble grows the pressure forces a small amount of ink out onto the paper. When the bubble finally bursts, it creates a vacuum, drawing more ink from the reservoir to replace the ink ejected onto the paper.

Piezoelectric printers on the other hand, use a piezoelectric crystal located at the back of each print head. As a small electric charge is applied to the crystal, it vibrates, forcing a small amount of ink out of the nozzle and onto the paper. As the crystal returns to its original, calm state the void left by the ejected ink creates a vacuum that draws more ink from the reservoir. Piezoelectric printing technology was patented by Epson and is used primarily in its inkjet printers.

Thermal bubble print heads

Figure F

This question turned out to be the most difficult, only 29 percent of those who took the quiz knew the correct answer: 300 to 600, as shown in Figure F. As described in the section above, thermal bubble, or bubble jet, printers use heat to expel the ink from the print head nozzles onto the paper. These nozzles are approximately the diameter of a human hair and a typical print head might have as few as 300 or as many as 600.

Dot-matrix printers

Figure G

Most of our quiz takers finished up with a bang. The correct answer is: Multilayer forms. In Figure G, you can see that 96 percent of you knew that. Because of their design, neither laser nor inkjet printers can print on multilayer forms. Only an impact printer, which uses pins to physically strike the paper, can print through a multilayer form’s various sheets. Dot-matrix printers are the most recognized type of impact printers.

Let’s work on our printer mechanics
While most of the members who took our quiz nailed questions two and five, the other questions illustrated a significant need for more information on the inner-workings of laser and inkjet printers. To learn more about both laser and inkjet printing check out these other TechRepublic articles:

As mentioned in the previous pop quiz results article, you get the TechPoints for just taking the quiz, not for getting all the answers correct.

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If you have a topic you’d like us to cover in an upcoming pop quiz, we want to hear about it. Drop us a line and share your suggestions for both quiz topics and questions. If you would like to comment about this quiz, please post a comment to this article. Good luck on our next quiz!