The photocopier has evolved from being a luxury to a necessity in any modern office. Many people take the performance of a photocopier for granted. Do you have any idea how these amazing machines produce exact copies of a document?
What is the one basic physical principle that makes a photocopier work?
What is a good way to see a simple version of the "opposites attract" principle in operation?
You can generate a static charge on a balloon by rubbing it on a sweater and see it attracting bits of paper.
Create a static charge by combing long hair briskly with a plastic comb and then placing it near bits of paper.
Both of the above
Correct Answer
Wrong Answer
Toner cartridges do not generally have a charge, but you can generate a static charge on a balloon by rubbing it on a sweater and stick it to a wall. You can do the same thing with a plastic comb by combing long hair briskly and then put it near to bits of paper and the paper will jump to the comb.
How does an image get from the paper onto the copier drum?
The drum is selectively charged by static electricity to match only the white spots on an original.
The drum is charged by static electricity, positive for black spots and negative for white spots on an original.
The drum is selectively charged by static electricity to match only the black spots on an original.
Correct Answer
Wrong Answer
The drum is selectively charged by static electricity to match only the black spots on an original. Toner is attracted to the drum only where there is a static charge relating to the black on the original.
What happens with your original document after you place it on the glass and press the start button?
The document is subjected to focused intense ultra violet light moving from one end to the other.
The document is subjected to focused intense infrared light moving from one end to the other.
The document is subjected to focused intense incandescent light moving from one end to the other.
Correct Answer
Wrong Answer
The document is subjected to focused intense incandescent light moving from one end of the page to the other. Light is reflected from white areas of the paper to strike the rotating drum below.
What is the electrical state of a drum before light is reflected onto it from your original?
The entire surface of the drum is charged with a positive charge.
The entire surface of the drum is charged with a negative charge.
The entire surface of the drum is made neutral, carrying no charge.
Correct Answer
Wrong Answer
The entire surface of the drum is charged with a positive charge. The light reflected by white areas of your original removes positive charge from the drum in the spots where light hits.
How does light manage to remove the positive charge from areas on the drum?
Wherever a photon of light hits the photoconductive drum, emitted electrons neutralize the positive charges.
Wherever a photon of light hits the photoconductive drum, emitted electrons reverse polarity of charges.
Wherever a photon of light hits the photoconductive drum, emitted electrons intensify negative charges.
Correct Answer
Wrong Answer
Wherever a photon of light hits the photoconductive drum, emitted electrons neutralize the positive charges. The dark areas on the original do not reflect any light leaving corresponding positive charges on the drum.
Toner is not an ink but rather a fine plastic-based powder that is negatively charged. In the old days, toner was made with carbon, which has been replaced by several different polymers to improve copy quality.
What is the coating of photoconductive material on the drum usually made from?
selenium or silicon
germanium
both of the above
Correct Answer
Wrong Answer
Many photocopier drums have a coating of a semiconductor called selenium on them to form a photoconductive coating. Silicon and germanium are also used for this purpose, but less frequently.
How does the toner manage to stay on the paper once the paper looses its positive charge?
Paper containing the image is heated and pressed in order to fuse the toner image to the paper.
The copy of the image is sprayed with a fine mist of setter fluid and dried by a heating bar.
The paper is heated at the same time it is charged causing the toner to stick to the spots where it is attracted.
Correct Answer
Wrong Answer
The paper containing the image is heated and pressed in order to fuse the toner image to the paper. This is why toner is made from pigmented plastic beads, which melt, making a bond with the paper.
What components inside a photocopier charge the drum and paper with a positive charge?
static collator
ion generator
corona wires
Correct Answer
Wrong Answer
The corona wires inside the photocopier are electrified with a high voltage, which they subsequently transfer as a positive charge, to a drum or a blank piece of paper in the form of static electricity.
What function does the lens have in a photocopier?
The lens serves to increase intensity and focus of light from the lamp onto an original document.
The lens allows you to adjust fine focus of an image to improve clarity of your original onto an enhanced copy.
Both of the above
Correct Answer
Wrong Answer
The lens serves to focus an image onto the drum below it and to allow reduction or magnification of an image. Unfortunately, there is no lens to improve on the clarity of any original document.
What is the function of the fuser inside a photocopier?
Without allowing any sticking, the fuser must melt and press toner into the paper.
The fuser shoots microwave energy at the copy without touching it in order to melt the toner into the paper.
The fuser interrupts power to your photocopier to protect it from damage due to an electrical problem.
Correct Answer
Wrong Answer
The function of the fuser is to melt and press toner into the paper containing a copy without any of it sticking to the fuser. The rollers of the fuser are heated with an internal quartz lamp and are coated with Teflon to prevent sticking.
