If you have no video experience, you may have to try a couple things to get what you want. Buying from a source that allows returns might be a good idea.
It appears you are after a well lit tablet and video capture. It seems to me that there may be special equipment for that purpose but i don't know where to look for it. If not available, it seems easy to mount any camcorder via its tripod screw to a stand, aim and record. The tripod screw is normally a standard 1/4" x 20 thread and you can get those in any length at any hardware store. So, the stand can be made from anything you might already have.
Most camcorders and cameras allow you to adjust the white balance so that, under any form of light, the white paper would be white. Your first sample video had paper with a blue cast. You might have to experiment with multiple lights to eliminate shadows. You should be able to do that with reflector equipped clamp lights, also available at hardware stores.
The camera I own that i would use for this is a Sony HX9V. The current model of that camera is a Sony HX20V. It has more controls than a webcam, so things like color balance might be better.
I know nothing about webcams, so it may be that, as a cheaper approach, it could work equally well.