Paper path movement detecting device for paper production control, has sealed spherical lenses arranged at front surface of optical housing facing paper path to be illuminated

摘要

The infra-red (IR) light source (26) illuminates the paper path (20) through the light guide fiber in optical housing (38). The light reflected from the path passes through another fiber arranged in the housing, to the polychromator (28). Multiple sealed spherical lenses (42,44) are arranged at the front surface (40) of optical housing facing the paper path. The lenses are optically connected to fibers.