ink pad 
noun
An ink-soaked pad in a shallow box, used for inking a rubber stamp or taking fingerprints.The ceremony to announce the emblem is rooted in Oriental culture with the Chinese seal, the red ink-pad, the special paper and the Chinese-style long table....
- It bears police approved wording and must be used with a red ink-pad.
- Lay the stamp onto a flat surface and tap the ink pad repeatedly over the surface of the rubber stamp.