Photoelectric paper basis weight sensor

Apparatus for performing an operation on energy transmissive sheets comprising:

• means for defining a feed path for movement of the sheets;
• a sheet working station along the feed path, the working station including means for varying a processing parameter to which the sheet is subjected at said working station;
• a sensor adjacent the feed path for defining a detection zone for said sheets, said sensor including energy emitting means for emitting energy into the detection zone and energy detecting means for giving an output signal related to the amount of energy from the emitting means passing through the detection zone to the detecting means;
• means responsive to the energy detecting means for determining the basis weight of a sheet in said detection zone;
• and
• means for generating a control signal to control said means for varying a processing parameter, in response to a sheet basis weight determination by said basis weight determining means.

Imaging apparatus for forming images on energy transmissive sheets comprising:

• a work station for performing an operation on said sheet, said work station including means for varying at least one operating parameter in accordance with the basis weight of a sheet undergoing said operation at said work station;
• a detector positioned along the feed path and defining a detection zone in the feed path for detecting sheets in the feed path, the detector including an energy emitting means for emitting energy into the detection zone and an energy detecting means for receiving energy transmitted through the detecting zone from the energy emitting means and for giving an output signal related to the amount of energy received by the energy detecting means;
• determining means for determining the basis weight of sheets in the feed path in response to the output signal from the energy deteoting means;
• and
• means for varying said at least one operating parameter in response to a basis weight determination made by said determining means.