Abstract: A type band for a printer comprises a track of marks to be scanned (timing marks) at least one of which is obliquely positioned relative to its adjoining marks. The centers of all marks are equidistantly spaced. When the horizontally moving type band is vertically displaced, the time spacing of the scanning signal of the obliquely positioned timing mark is changed over the scanning signal of its adjacent timing mark. The magnitude of the vertical displacement of the type band is derived from the change in this time spacing. The displacement data thus obtained permit compensating for the vertical displacement of the type band (using, for instance, a stepper motor).

Abstract: Method and apparatus for the constant speed control of a brushless DC motor, whose pole windings receive a pulsed control voltage between their commutation points, control being a function of the speed characteristics of the motor, and the commutation points being synchronized with the drop times of the motor current and the control voltage pulses. In a state in which there are no load changes, the motor current substantially rises or drops between a maximum value I.sub.max and a minimum value I.sub.min according to the pulse mode. In the event of changes in the motor load, a mean motor sum current is retained for maintaining the speed.

Abstract: Bank for accommodating adjacent ram units. Each of these consists of a flat, narrow frame. A tongue-shaped ram, driven by an electromagnetic actuator, extends in a recess of the frame. For accommodating and guiding the individual print ram units, the bank is provided with a receiving bar and a comblike holding bar between which the frames are arranged. Extension pieces of the lower frame elements can be accommodated by slits in the receiving bar. The upper frame elements are held in recesses of the comblike holding bar. The tongue-shaped rams are laterally guided by the electromagnetic actuators which are arranged on both sides of the frame and are aligned to each other.

Abstract: A program selector in an electronic calculator has a number of formulas which are printed in human readable form. When a formula is selected by the operator a machine readable representation of the formula is positioned adjacent a transducer. The transducer generates an electrical signal which represents an identification of the particular mathematical formula or other type of program to be executed by the electronic calculator. The electrical signal is decoded by a decoder which generates a storage address for the starting point of the formula or program to be executed.

Abstract: An ink jet printer prints dot matrix characters by removing unwanted drops from a sequence of uniformly spaced drops in an ink jet stream and subjecting the remaining print drops to a vertical raster deflection in timed relation with relative horizontal motion of the jet stream and a record medium. Selected print drops are individually deflected fractional amounts in either the horizontal or vertical direction prior to the vertical raster deflection to cause the selected print drops to be deposited at positions intermediate the coordinate intercepts of a rectilinear matrix pattern to cause dot matrix characters to be printed with arcuate line segments and various angles corresponding with conventional character shapes.