摘要 |
A proximity caliper for sensing the correct thickness of printed signatures is mounted on an apparatus for feeding printed sheets. A metal gripper which retains a signature against a rotatable drum traverses the caliper as the drum transfers the signature from one point to another. The proximity of the metal gripper with respect to the caliper is a function of signature thickness. Hence, the signature having too many or too few pages is detected. The proximity caliper includes at least two proximity sensors which do not come in contact with the metal gripper. The position of the sensors is adjustable with respect to the rotatable drum to accommodate signatures having a wide range of different thicknesses. The sensors are also adjustable with respect to each other to control the sensing tolerance. Signatures of the correct thickness are transferred by the drum and normal operation of the feeding apparatus proceeds. Signatures which are detected as having an incorrect number of pages may be removed.
|