Two-dimensional ink droplet sensors for ink jet printers

摘要

Mounted at every other intersection of the deflection planes of the ink droplets issued by a multi-nozzle printhead of a pagewidth continuous stream ink printer are two-dimensional differential optical sensors. These sensors are located near the printing plane and gutters of the printer and comprise first and second input optical fibers, each having one end coupled to a common light source and the other free ends directing light towards aligned confronting free ends of respective associated pairs of output optical fibers. One of the input fibers and its associated pair of output fibers are inclined with respect to the other, though both input fibers and their associated pair of output fibers are either coplanar or contiguous with the same plane. The opposite ends of the pairs of output fibers are respectively coupled to differential circuits via photodetectors, so that each sensed droplet position may be determined relative to both the droplet deflection plane and the plane perpendicular thereto as the droplet travels along its flight path therepast.