Record feeding apparatus and method

Abstract

There is disclosed a method of feeding record webs or sheets and apparatus for carrying out the method. The record feeding apparatus is shown in conjunction with a printing apparatus having a print head assembly, platen structure, a mechanism for severing a printed record from the remainder of the record and an inking mechanism. The record feeding apparatus includes an edge guide, a rotatable feed wheel having a planar frictional surface which engages one face of the web to exert a resultant drive force on the record when driven, the resultant force being comprised of a force vector of large magnitude extending in the longitudinal direction for feeding the record longitudinally and a force vector of small magnitude extending in the lateral direction for causing the record to be driven laterally to cause its side edge to be in guided contact with the edge guide. A roll cooperates with the frictional surface to provide a pinch point disposed either upstream longitudinally of the rotational axis and laterally between the rotational axis and the edge guide or downstream longitudinally of the rotational axis and laterally beyond the rotational axis. A record stepping method and stepping motor and stepping motor control logic are employed to carry out the method to accurately position the record for printing and severing. The stepping motor control logic includes circuitry for advancing the stepping motor either a full increment or one-half of a full increment to provide increased position accuracy without sacrificing drive speed. A current regulated stepping motor driving circuit is used to provide high stepping motor torque without drawing excessive current, and a variable rate stepping pulse generating circuit is employed for gradually accelerating and decelerating the stepping motor. Timout circuitry for disabling the operation of the stepping motor in the event of an abnormal condition is also provided.