Abstract: A paper tray having a bottom, front and rear walls extending upwardly from the bottom, and side walls extending upwardly from the bottom to define an open boxlike structure for storage of sheets of paper in readiness for use. A paper receiver is pivotably mounted on the tray for receiving sheets of paper after printing thereof. The paper receiver has a first position in which paper can be fed automatically from the tray to a print roller and a second position in which paper can be manually fed to the print roller. In the automatic mode, the paper is fed by a drive roller to produce a buckle at its leading position to insure alignment at the print roller and subsequent straight, unskewed feed. The paper receiver carries a conveyor belt driven from the print roller at a greater linear speed to insure positive feed of the paper from the print roller to a receiving station.

Abstract: A method of stopping a feedback-controlled stepping motor having a stator and a rotor wherein the drive of the stator field is leading the rotor by more than one step and the rotor is rotating with an angular velocity within a first range of values is performed by decreasing the drive lead of the stator field from its slewing value to another value whereby the angular velocity of the rotor decreases below the first range and sensing for the decrease of the angular velocity of the rotor to within a second range of values so that when the angular velocity of the rotor is within the second range of values the rotation of the stator field is stopped to brake the rotor.

Abstract: A paper tray has a first bottom, first front and rear walls extending upwardly from the first bottom, first and second side walls extending upwardly from this bottom. The walls and bottom define an open boxlike structure for storage of sheets of paper prior to use. A cover is pivotably mounted to the top of the lower side walls in the region of the rear wall extends toward the first front wall. The cover is shorter than the first bottom to provide a feed gap between the free end of the cover and the front wall so that paper can be removed from the boxlike structure. Each of the lower side walls has an extension upwardly extending beyond the level of the cover. Paper receiving means has a second bottom upwardly displaced from and overhanging the feed gap and the front wall. First and second upper side walls are connected to the ends of the extensions remote from the rear wall and extend upwardly from the upper bottom.

Abstract: A stepping motor system is shown wherein a method is employed for determining the optimum amplitude of the current supplied to the stator winding of the motor. A series of different currents are applied to the motor. First, the stator windings are energized with currents of certain base magnitudes. Then the current in one winding is increased by a small amount and the current in the adjacent winding is decreased by a small amount so that the rotor tends to move towards its new equilibrium position. When the rotor reaches its maximum displacement the current changes in the windings are reversed so that not only will the rotor "hunt" for its new equilibrium position but it overshoots with twice the magnitude. This process continues for certain period of time during which the oscillation magnitudes rapidly grow. In one embodiment, after a maximum amplitude is reached, the current changes are applied out of phase with the oscillations to now try to decrease their amplitude.

Abstract: An open loop control device and method are provided for stepping motors. By energizing a motor so that the rotor motion is the result of a revolving field which is of piecewise constant speed and uniform field strength, the rotor can be brought to a stop at any desired position. Such position can be the same as or different from the conventional full-increment or half-increment detent positions of the motor. This control method and device guarantee that there is no oscillation when the rotor reaches its final position. The field windings are energized in sequential manner and such that the resultant field takes into account the magnetic characteristics of the motor. The revolving field can be initially adapted to produce, in one case, an angular velocity of half the desired speed for purposes of accelerating the rotor. After one-half of a resonant period has elapsed, the rotor is accelerated to the desired speed. At this time, the speed of the field is doubled and the rotor fully synchronized therewith.