When you Tippex over laser-printed text it leaves indentations. Why?

Question

If you get a page produced on a laser printer, and put Tippex on to it (I was using Tipp-Ex Aqua - does the same happen with non-water based Tipp-Ex?) you can still see faint indentations in the Tippex corresponding to the outlines of the letters underneath. This isn't evident when the Tippex is wet; the indentations slowly appear as it dries and are still apparent even through two layers, but it doesn't happen when Tippexing over ink from a biro.

Any ideas? I know this is hardly a burning question. However, it is a really quiet day in work and I'm bored.

Answer 1

The 'ink' in a laser printer or photocopier is made from plastic.  This exists inside the printer as powder (the toner).  The print is fused to the paper by heating the powder up and melting it.  The print that is left is much thicker than the ink from a biro and the plastic prevents the tip ex from soaking into the paper.

Answer 2

I would guess it has something to do with the rate in which the paper absorbs the liquid part of the correction fluid in comparison to the printed areas.  For example, the unprinted paper may be more or less absorbent than the paper with toner printed to it.  This will cause the correction fluid on the two different parts to dry at different levels.

It probably makes very little difference whether you are using water based or non water based tipp ex.  Again there may be differences in the absorption rates between the two different types of tipp ex but the paper/toner will still absorb it to an extent so there will most likely still be an indentation in your correction.

Answer 3

Not sure but i find it impossible to see my laptop screen after i finish tippexing  

Answer 4

Firstly, Where do you work?! if things get that dull, it must be a real hoot on a "party" day! (No offence)

I think its because of the way things are printed...

Maybe you should ask the toner guy?!

I can however explain why it doesn't happen with biro :-)

Biro's indent the page rather than glide over it, so when you use Tippex on it, it tends to "flood" to the indented area. This means that it will fill in the inked area but not the area around. which is good. Right?