Minor nitpick, robots can pick up paper
Robots can definitely pick up bits of paper from a desk - industrial processes use a rod with a row of suction holes in it so the technology does exist.
To scale it down, one or two holes at the end of an arm (or ends of fingers if you have the fancy one) attached to a bendy pipe with a dustbuster at the other end.
Anyone who has ever tried to hoover their home office area will be familiar with this principle and how well it works, especially when you get too close to those receipts that are just small and flimsy enough to disappear...
p.s. handheld hoovers aren't always that good for actual dust, you'll need a coffee tin, a mini paper hoover bag, some tape and a cardboard tube to fix that. Get the right size cardboard tube and you can use regular attachments too.