Stamp unit with a circumference portion covered by a sealant

摘要

The disclosed invention is a stamp unit that includes a holder member having an end. A stamp material is made of a porous material retained by the holder member. The stamp material has a front surface projected form the end of the holder member and a circumference portion. The front surface includes an effective stamp surface that includes a stamping portion and a non-stamping portion. The circumference portion is defined at least by an area existing between positions corresponding to the end of the holder member and the effective stamp surface, within an exposed area of the stamp material from the holder member, the area being entirely covered by a sealant.