Postage meter with improved paper path

摘要

A postage meter has the print rotor and platen within a single secure housing, with a letter detection lever along the paper path downstream from the rotor. The letter detection lever is in a spring-loaded coupling relationship with the trigger that triggers franking. If a letter remains in the meter due to a paper jam, the detection lever continues to be actuated and the spring-loaded coupling keeps the trigger in the triggered position. The meter further comprises a platen carrier moving the platen toward and away from the rotor; when the rotor is in its home position a radial cam on the rotor and cam follower keep the carrier away from the rotor. When franking of a letter begins and the rotor begins to rotate, the rotor cam releases the cam follower, permitting the carrier to move up in spring-loaded relation toward the rotor. A letter stopper is in the paper path downstream from the rotor and helps to align the letter so that the postage imprint is optimally oriented on the letter. The trigger includes an enclosure containing a free-moving mass; the weight is constrained from radial and axial movement relative to the trigger pivot. The trigger is balanced in two axes in the plane in which it rotates, thus it has no net moment (or minimal net moment) about its pivot. The mass and the enclosure shape are selected to damp movement of the trigger as it returns to its home position after it is triggered.