| 摘要 |
<p>A sheet feeding device for printers and other machines comprises a movable support (17) whereon a stack of sheets may be arranged and resiliently urged against selection wheels (19). A retracting mechanism (50) is arranged so as to push back during one phase of a selection cycle the movable support (7) by a predetermined distance which is substantially constant and independent of the thickness of the stack of sheets. The retracting mechanism (50) for this purpose comprises a connecting rod (58) displaced by a cam wheel (66) following a backward and forward movement. The connecting rod (58) bears a pawl (57) cooperating with a ratchet wheel (56) suitable for driving a lever (51) integral with the movable support (17). Additionally an actuating mechanism permits the partial opening of the guiding channel (28) when the sheet arrives in a printing zone (35). Thanks to these characteristics, the movements of parts, and in particular of the movable support (17), may be kept to an optimal and constant minimum, which ensures fast, precise and noiseless operation. Printing of great precision is also obtained. <IMAGE></p> |
