Abstract: Improved cursor-positioning apparatus is disclosed for use with a mouse-type cursor controller and a host computer display system to enable the mouse's operating area to remain relatively small, yet enabling normal-feeling mouse operation to provide both high-precision cursor pointing and very efficient coarse positioning of the cursor to any zone of a relatively larger display area. The disclosed apparatus provides an ideally limited operative-area for the attached mouse, comprising structure for defining a boundary limiting the range of X-Y movement of the mouse when it is operated within such contained operative-area.

Abstract: A circuit for use in an ink jet printer in which the carriage motion either approximates a sinusoidal vibratory pattern, or which has any variable velocity pattern that reliably repeats from cycle to cycle. It is further assumed that the printer will print in both directions of the carriage, and that the flight time of the ink drop from jet to paper is constant. A counter starts at a value corresponding to the flight time of the ink drop, and then measures the time of the carriage over a predetermined distance. The difference is the required delay. A second delay counter uses this value to produce a time delay prior to ejecting the ink drop. Since, in an actual ink jet printer, several drops will be in transit at the same time, the circuit is provided with a plurality of phases or channels which operate concurrently.

Abstract: A drive circuit for a drop-on-demand ink jet ejector. Both drive pulse amplitude and drive pulse width are programmably controlled by utilizing simple digital circuitry.

Abstract: A method for eliminating mechanical crosstalk in a drop-on-demand ink jet array by inducing electrical crosstalk using passive elements, which effectively neutralize the mechanical crosstalk.

Abstract: A simple graphic engine in which a document reading array and an array of marking elements are supported on the same support member. The support member is scanned in a direction orthogonal to the direction of relative movement between the support member and the document to be read and/or the record-receiving member. The support member is oscillated axially during scanning to reduce the number of elements required in both the scanning and marking elements.