摘要 |
A data printer having removable, and interchangeable, paper-feed modules, such as may embody a tractor or pin-feed-type paper-feed mechanism. The interchangeable modules each have guide ways which cooperate with and move along complementary guideways supported by the printer main frame to guide the selected module into place and seat it in a particularly defined position. A mechanical latch locks the seated module to maintain it in place. The paper-feed mechanism of each module is driven by a rotatable member, with the power train including a motor-driven worm mounted on the printer and a mating worm-gear carried on the removable paper-feed module. The worm is mounted in an upright position, and the worm-gear moves into mating relation with the worm by travelling an upright path, but with a small acute angle between such paths. The worm and worm-gear have a tooth or thread profile with a rounded nose section. |