Abstract: In an electrographic recorder of the type wherein a dynamic toner bridge is formed between a rotating shell and a permeable strip positioned a predetermined small distance from the periphery of the shell, to define a recording station, means are provided for varying the magnetic field defining the toner bridge by varying the intensity of the defining magnetic field.

Abstract: In a twin tube recording CRT system, apparatus is provided for accurately aligning the line scan trace of the two tubes with respect to each other. The positioning voltage applied to the vertical deflection plates of the two tubes is compared in a comparator network. When a substantial identity of the compared signals is detected by the comparator network, suitable indicating device, such as LED's, are actuated to indicate the proper alignment, without the need for visual reference to the face of the tubes. There is also provided an interrelated skew correction circuit for the two tubes wherein a sample-and-hold circuit samples the skew correction signal for the first tube at a selected point in the sweep thereof. That sampled signal is superimposed on the skew correction signal for the second tube, to effect an offset of that skew correction signal by the amount of the sampled signal of the first tube skew correction signal.

Abstract: Overlapping, and consequent illegibility, of recorded line scan or transverse records are precluded by delaying or inhibiting the recording process until the record sheet is being driven at or near full speed with respect to a normally blanked cathode ray tube record marking means. A voltage is established by a record speed select switch which must be substantially equaled by a voltage produced by a record sheet speed transducer before a comparator will turn on. The comparator output signal then allows the cathode ray tube to be unblanked and recording to start.

Abstract: In a twin tube recording CRT system, apparatus is provided for accurately aligning the line scan trace of the two tubes with respect to each other. The positioning voltage applied to the vertical deflection plates of the two tubes is compared in a comparator network. When a substantial identity of the compared signals is detected by the comparator network, suitable indicating devices, such as LED's, are actuated to indicate the proper alignment, without the need for visual reference to the face of the tubes. There is also provided an interrelated skew correction circuit for the two tubes wherein a sample-and-hold circuit samples the skew correction signal for the first tube at a selected point in the sweep thereof. That sampled signal is superimposed on the skew correction signal for the second tube, to effect an offset of that skew correction signal by the amount of the sampled signal of the first tube skew correction signal.

Abstract: A recording apparatus includes a plurality of Xenon flash tubes and a separate enclosure for each of said flash tubes. Each enclosure is provided with a slit through which light from the associated flash tube emerges to form a relatively small line segment. The slits are all located in a recording plane and may be disposed in an H-shaped or C-shaped recording array, as desired. When placed in cooperative relation with a moving light sensitive recording medium that is ultrasensitive to a predominant wavelength of the light produced by said flash tubes, selective and appropriate flashing of said flash tubes produces dense analog time code and other traces on said recording medium.