Hello,

For the forensic investigation of documents a certain technique is used to make indented writing visible. To improve this process we would like to buil this in to a copier.

As you might know the copier consists of a charged ciliner coated with polymers, the photoreceptor, on which the original is projected. The photoreceptor discharges where the light hits it and keeps its charge on the places where the original is black, so generating a so called latent image: fringe fields above the surface due to differences in surface charge.

For the detection of indented writing we generate these fields also but I was wondering if there is a material that could copy the electric field.

For instance:

Two cilinders, one the cilinder without the image, the second one a cilinder with the latent image. Now I would like to charge the first cilinder with the image that's on the second cilinder (the one with the latent image).

Do you know a material for the first cilinder to do so, or isn't this possible? If this is possible would it also be possible that the second cilinder would have a stronger latent image?

I hope you can give me a clue. Thanks in advance

Jonathan Martens