Understanding Copy Machines: The Science Behind Positive and Negative Charges

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In the discussion about why black sends a positive charge through a copy machine while white sends a negative charge, it is clarified that the color itself does not create the charge. Instead, a specific cylinder within the copier is initially positively charged. When light is directed at the paper, black areas absorb the light while white areas reflect it. This reflection causes the cylinder to lose its positive charge in the white areas, resulting in a neutral charge. Consequently, the cylinder retains a positive charge only in the black areas, allowing negatively charged ink to adhere to these spots. The process concludes with the cylinder transferring the ink onto white paper, creating the final copy.
RuroumiKenshin
Why is it that black sends a positive charge through a copy machine while white sends a negative charge? I presume it has something to do with the wave lengths?

If you don't know how a copy machine works, consult me. I have an unexplained obssession of learning about copy machines (and it is more like a craving).
 
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Originally posted by MajinVegeta
I have an unexplained obssession of learning about copy machines (and it is more like a craving).

Maybe you have Asperger Syndrome? Nah... I'm just joking with you.

eNtRopY
 
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Originally posted by MajinVegeta
Why is it that black sends a positive charge through a copy machine while white sends a negative charge? I presume it has something to do with the wave lengths?

If you don't know how a copy machine works, consult me. I have an unexplained obssession of learning about copy machines (and it is more like a craving).

It is not this way Majin.
It is not that the black or white makes the charge !
What actually happens (as far as i remmember) is that a certain cylinder gets positively charged (and it is made of a certain material).
Then light is pointed towards the paper so that it reflects on this cylinder, black color will absorb the light, while white color will reflect the light.
Therefore light will reach the cylinder only from places that where white.
Now due to the photoelectric effect, the positive charge that where on the cylinder will become neutral the places where light came (iow, the white places).
So the cylinder will be positively charged only in the places corresponsing to black places in the original paper.
Afterwards negatively charged ink will be put on the cylinder, it will only attach to the places that are positively charged on the cylinder (places where light didn't come, therefore correspond to black places).
Then cylinder slides over a white paper, the paper is dried, and comes out from the machine.

My information are rusty in my mind, so maybe i am wrong ..
 
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