The link above k3libre. does exactly that. but remotely from a PC.
Are you asking if there is like a keyboard shortcut to take screenies??
Please make the question clearer, that is two decent answers to what we thought was the question... IF they aren't? I really don't understand that question.
Do you mean for example you DO NOT want to us a PC in the process.
or you CAN ONLY touch the kindles keys during the process..
OR something??? Need more info