Dickenmessapparat für blattförmiges Material.

摘要

A sheet thickness detector comprises first and second moveable guide surfaces (1,4-2,5) defining a nip (7,8) through which a sheet passes in use. A sensor (32) senses relative separation movement between the guide surfaces. The first surface carries a rib (16,17) extending generally along but at an angle to the direction of movement of the surface whereby the rib moves laterally relative to the second guide surface at the nip, and whereby any portion of a sheet extending in the direction of movement of the sheet and having a thickness greater than the majority of that section of the sheet passing through the nip, the thickness of the portion being no greater than the depth of the rib, will cause substantially no change in the relative separation of the surfaces except when the portion is sandwiched between the rib and the second surface.