| 摘要 |
<p>OBJECT DEFLECTION SENSOR An ink drop height sensing device for an ink jet recording apparatus, the apparatus including a nozzle for forming and propelling a stream of ink drops towards a recording media in a predetermined deflection plane. A light source on one side of the intended path or trajectory in the plane of deflection of the ink drops impinges upon a mask located on the opposite side of the plane, which mask is aligned with a light sensitive device such as a phototransistor located behind the mask. The mask includes first, second and third line sensors, in the illustrated instance serially arranged slots with at least two of the slots being in parallel relation, the third slot being inclined with respect to the parallel slots and positioned with respect to them so that at a predetermined point along its length, it is a predetermined distance from the next adjacent slot relative to the distance between the two parallel slots. The phototransistor is coupled to a timer for comparing the time intervals for the passage of the ink drop between the parallel slots which is compared with the time taken for passage between one of the parallel slots and the inclined slot. If the time of the drop travel between the parallel slots is determined, (the distance being fixed), and the time of drop travel between one of the parallel slots and the inclined slot is compared to that time interval, dependent upon whether the time measurement is longer or shorter, then it may be determined whether the drop is high or low in the deflection plane and suitable correction may be employed to bring the deflected ink drops to their predetermined deflection height or trajectory path. LE977008 1</p> |
