| 摘要 |
A precision positioning printhead transport apparatus comprises a differential wheel (18) rotatably mounted upon a printhead carriage (10) and having an endless belt (24) wrapped around portions of different diameter such that when the belt (24) is moved around its path between pulleys (26,28) both differential wheel (18) engaging loops cause the differential wheel (18) to rotate in the same direction. A motor (30) drives either the differential wheel (18) itself or a driven pulley (28) to cause the differential wheel (18) to rotate and move the printhead carriage (10) along a fixed path (12) by a distance equal to the difference moved along the portions of the differential wheel (18) relative to the endless belt (24). |
