摘要 |
A concentrate sense window which defines a variable thickness flow path area is provided for sensing the concentration levels of inks having varying levels of luminance. Sensor window panels are configured in relationship to each other such that an area defined therebetween varies from a first area to a second area. An emitter/detector pair are located on opposite sides of the sensor window. The emitter transmits a signal through the sensor area and at least part of the signal is sensed by the detector. The emitter/detector pair are designed so as to be movable along the surface of the sensor window whereby ink of varying illuminance may be sensed without the need of separate windows or multiple emitter/detector pairs.
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