Abstract: The invention is directed to a device for clamping sheet-shaped film material onto the recording drum of a reproduction device and is directed to the operation of this device. The recording drum comprises axially proceeding suction-hole rows for the vacuum-fixing of the recording material. Suction channels, each of which connects the suction holes of a suction hole row to one another, proceed in the wall of the recording drum. A vacuum distributor controllable by the rotational movement of the recording drum is arranged in the recording drum, this controllable vacuum distributor selectively bringing the individual suction channels, the corresponding suction hole rows into communication with a stationary vacuum pump. The vacuum distributor is controllable such that that suction hole row on which the starting region of the recording material lies is first charged with vacuum during the clamping event.

Abstract: In the implementation of the method for manufacturing a texture drum, a surface structure is produced in the region of a surface with an electron beam, preceding a charging occurring within a working interval with an electrons beam having an energy density generating a recess, the texture drum is charged during a pre-treatment interval by an electron beam having an energy density that leaves the surface structure essentially as it was formed.

Abstract: A method and apparatus for color stimulus specification-correction, i.e. sensation-correction pickup for scanning of chromatic image originals, referred to in short as a multispectral scanner. A color image pickup system is provided, based on the multispectral principle, the plurality of I>>3 narrow-band spectral filters and one black filter being introduced into the optical beam path of the image scanner, and thus I narrow-band spectral separations of a color image original and of a white image original are registered and digitized. Spectral pixel samples individually calibrated for all pixels are formed with an electronic evaluation unit in pickup real time. These are either stored in I parallel image storage levels or are multiplied by specific coefficients from a table in pickup real time of the signals in three parallel channels and are accumulated in three parallel image storage levels.

Abstract: A method and apparatus for controlling a synchronous motor with an AC voltage. A rated value proportional to a desired frequency of the AC voltage and related to a rotational speed of the synchronous motor is provided. The rated value is continuously added up in an accumulator to provide added-up signal values. The added-up signal values are employed for addressing stored function values in a function value memory, the function values representing at least one AC voltage. The addressed function values are read out from the function value memory and are converted into at least one AC voltage having the frequency corresponding to the rated value. The AC voltage is supplied to the synchronous motor for generating a rotary field such that the frequency of the AC voltage defines the rotational speed of the synchronous motor.

Abstract: The invention concerns a process and circuit for correcting the light-power output of a laser diode. The circuit comprises a generator (2) for generating a driver current (I.sub.T) which determines the light-power output of the laser diode. The driver current (I.sub.T) is modulated by a modulation signal (B). To correct the light-power output, the circuit includes a linear low-pass filter (5) which is acted on by the modulation signal (B) and which approximately simulates the change with time of the internal temperature of the laser diode (1) as a function of the modulation signal (B). The output signal of the linear low-pass filter (5) acts as a driver current (I.sub.T) correction signal (K), thus compensating for the temperature dependence of the laser-diode light-power output.

Abstract: The invention relates to a process and circuitry for controlling a laser diode. To compensate for the temperature-dependent drop in the light intensity produced by the laser diode, the laser diode is controlled by a voltage generator with an adjustable internal resistance. A rise in the driver current of the laser diode as the temperature rises is set by the adjustable internal resistance in such a way that the rise in the light intensity produced determined by the rise in the driver current compensates for the temperature-dependent fall in the light intensity.

Abstract: The invention is directed to a method and to an apparatus for the correction of the positioning errors of a light ray deflected across a surface by a deflection system comprising at least one mirror face, said light ray moving transversely vis-a-vis the line direction relative to the deflection system. The light ray is generated with a laser diode that is displaceable transversely relative to the direction of the emerging light ray dependent on correction values. Before the actual operation, a plurality of positioning errors of the light ray are measured for every mirror face of the deflection system in the line direction (X-positioning error) and perpendicularly thereto (Y-positioning errors), measurements are made at measuring points orientated in the line direction on the surface. At least one X-correction value and one Y-correction value is generated for every mirror face.

Abstract: An optical color-splitter arrangement comprises a color splitter for spectral resolution of a light beam into at least two chromatic light beams of different spectral ranges. A correction device is arranged in each of the chromatic light beams for improving a color selectivity of the color splitter. Each of the correction devices has at least two dichroitic mirrors successively arranged on an optical axis of the respective chromatic light beam, each dichrotic mirror being arranged relative to the optical axis so as to define a normal operating position angle of incidence for the corresponding dichroitic mirror.