Abstract: A circuit arrangement for automatic, load-dependent control of at least one winding current of a respective motor winding of a self-timed bipolar stepper motor, includes a first power driver circuit for a first motor winding and a second power driver circuit for a second motor winding. The circuit arrangement includes a first XOR gate and a second XOR gate, and a first resistor connected so as to couple the first XOR gate to an anode of a first diode. A cathode of the first diode is coupled to the comparator input of the first power driver circuit via a second resistor. A third resistor is connected so as to couple the second XOR gate to an anode of a second diode. A cathode of the second diode is coupled to the current-controlling comparator input of the second power driver circuit via a fourth resistor.

Abstract: A circuit arrangement for automatic, load-dependent control of at least one winding current of a respective motor winding of a self-timed bipolar stepper motor, includes a first power driver circuit for a first motor winding and a second power driver circuit for a second motor winding. The circuit arrangement includes a first XOR gate and a second XOR gate, and a first resistor connected so as to couple the first XOR gate to an anode of a first diode. A cathode of the first diode is coupled to the comparator input of the first power driver circuit via a second resistor. A third resistor is connected so as to couple the second XOR gate to an anode of a second diode. A cathode of the second diode is coupled to the current-controlling comparator input of the second power driver circuit via a fourth resistor.

Abstract: A sheet conveyance system has at least one driven conveying shaft, with a variable spacing of the driven conveying shaft from the sheet stack. The driven conveying shaft includes at least one sheet conveyor that acts on the sheet to be conveyed with a friction coating. A toothed wheel is fixedly disposed on the conveying shaft, whereby this toothed wheel is enclosed by an outer ring that supports the friction coating and has an inner toothing constantly meshes with the outer toothing. The partial circle diameter of the toothed wheel is smaller than the inner toothing. A transferred force acts on the outer ring such that it is placed with a contact force onto the sheet. A spacer maintains a fixed spacing between the axis of rotation of the toothed wheel and the axis of rotation of the outer ring.

Abstract: A sheet conveyance system has at least one driven conveying shaft, with a variable spacing of the driven conveying shaft from the sheet stack. The driven conveying shaft includes at least one sheet conveyor that acts on the sheet to be conveyed with a friction coating. A toothed wheel is fixedly disposed on the conveying shaft, whereby this toothed wheel is enclosed by an outer ring that supports the friction coating and has an inner toothing constantly meshes with the outer toothing. The partial circle diameter of the toothed wheel is smaller than the inner toothing. A transferred force acts on the outer ring such that it is placed with a contact force onto the sheet. A spacer maintains a fixed spacing between the axis of rotation of the toothed wheel and the axis of rotation of the outer ring.

Abstract: An arrangement to hold a top sheet of a stack of sheets that are ejected by an office machine and deposited on the stack is disclosed. The arrangement comprises a holding element and a lifting device adapted to vertically move the holding element. A tension spring is adapted to be tensioned when the holding element is placed on the stack, thereby generating a placement force. The lifting device may comprise an upper part where the holding element is arranged and a lower part. The lower part is vertically driven, and the upper part and the lower part being connected by the tension spring. The holding element may be a holding flap that is pivotally positioned at the lifting device and is adapted to pivot between a swung out position that projects over a stack of sheets and a swung in position into the lifting device. A joint drive may effect the lifting movement of the lifting device and the swinging movement of the holding flap, the holding flap being driven by a sliding clutch.

Abstract: An arrangement to hold a top sheet of a stack of sheets that are ejected by an office machine and deposited on the stack is disclosed. The arrangement comprises a holding element and a lifting device adapted to vertically move the holding element. A tension spring is adapted to be tensioned when the holding element is placed on the stack, thereby generating a placement force. The lifting device may comprise an upper part where the holding element is arranged and a lower part. The lower part is vertically driven, and the upper part and the lower part being connected by the tension spring. The holding element may be a holding flap that is pivotally positioned at the lifting device and is adapted to pivot between a swung out position that projects over a stack of sheets and a swung in position into the lifting device. A joint drive may effect the lifting movement of the lifting device and the swinging movement of the holding flap, the holding flap being driven by a sliding clutch.

Abstract: A document conveyance device for conveying single documents on a document stack is described, which includes at least one driven conveying shaft with the interval of the driven conveying shaft from the document stack being variable. The driven conveying shaft includes at least one document conveyance system which comprises a toothed wheel, fixedly disposed on the conveying shaft, with outer toothing and a concentric ring with inner toothing. On the outer ring a friction coating is disposed. The teeth of the toothed wheel and the inner toothing are always meshed in an engagement point. A force component fed in under definition, engages the concentric outer ring such that a force component between the friction coating of the outer ring and the document to be conveyed is active.

Abstract: For driving a self-timing stepping motor which can be decelerated by an external load, a driving device presets a target step frequency and the motor is started with this target step frequency. The actual rotational speed of the stepping motor is determined and, as a function of this determined rotational speed, the target step frequency is changed when the rotational speed falls below a preset actual rotational speed of the stepping motor for a preset time interval.

Abstract: An arrangement for the control of movement of documents to an output device such as a printer or a copier in such a manner that the document draw-in rate automatically matches the document output rate. A document intake channel forces the incoming document into a curvature transversely to the direction of the transport of the documents, whereby the degree of curvature of the documents is a function of any tensile force on the documents. A sensor includes an analog and continuous output signal to affect a continuous change of the driving frequency for a motor causing the movement of the documents as a function of the actuation of the sensor.

Abstract: Bipolarity current-activated windings of powerful stepping motors for high step frequencies are to be indexed such that for each load condition the optimum motor torque is attained. The circuit configuration according to the invention comprises for this purpose chopped power output stages ((1, 2)) which are each activated by direction-dependent logic phase signals (PH12, PH34) of a signal generator (3) for the current feed into the motor windings of the stepping motor drive. Via a chopper pulse weighting circuit (4.2) winding indexing signals are supplied to the signal generator (3). To the chopper pulse weighting circuit (1,2) are supplied logic chopper signals (CH12, CH34) which can be tapped at the power output stages ((1, 2)) at the output side, and a device (7,14) connected to the chopper pulse weighting circuit (4.2) ensures that always only that chopper signal (CH12 CH34) is conducted to the chopper pulse weighting circuit (4.2), which is decisive for the next winding switch-over.

Abstract: The clearance-free fit for cylindrical mountings, in particular photographic lenses, is produced by recesses in the inner wall of a main mounting and projections in the outer wall of an individual mounting, to be fastened in the main mounting by inserting and by a relative rotary movement between the two mountings. The recesses and the projections are of such a configuration that a sufficiently large clearance s is present when the individual mounting is inserted, and this clearance is removed by turning to produce a frictional connection.