Abstract: A print quality enhancement arrangement for a dot matrix printer such as a thermal ink jet printer. The arrangement includes a buffer for receiving 300 dots per inch (dpi) resolution data in the horizontal (print head movement) direction and creates 600 dpi resolution data using image enhancement techniques. The arrangement further includes correction of the higher resolution data to remove pels which are unprintable due to the frequency response of the print elements in the print head. The correction is performed using knowledge of the history of printed pels and the original 300 dpi data. The creation of the higher resolution data and its correction occur "on-the-fly" as data is being fed to the print head, rather than through the creation of a 300 by 600 dpi bitmap.

Abstract: In a printer having P+X printing elements for printing pixels with a vertical center-to-center spacing R.sub.1 during a plurality of line scans, and a stepper motor for moving a record medium in increments R.sub.2 where R.sub.2 is greater than R.sub.1, all points addressable printing is obtained by a combination of movement of the record medium orthogonal to the line scan direction and shifting address signals applied to the print elements. The stepper motor moves the record medium a distance k.sub.2 R.sub.2 between successive line scans and address signals are applied to (n+k.sub.1)th . . . (n+k.sub.1 +P-1)th print elements to cause a shift k.sub.1 R.sub.1 such that the sum of the distance the record medium is moved before a line scan and the shift caused by the address signals during a scan is equal to PR.sub.1 where P is the number of print elements active during the preceding line scan, or equal to any desired integral multiple of R.sub.1 in other print modes.

Abstract: A voltage converter having switchable output capability is provided. The voltage converter converts an unregulated voltage input to a regulated DC voltage output. The regulated DC output level is selectable by changing the logical status of at least one logic input to the voltage converter, thereby converting a single voltage source to one of at least two selectable DC voltage outputs.

Abstract: The invention is for an improved method and apparatus of driving a stepper motor with multiple voltages. A first voltage is applied to the step motor winding for a driving phase, and a second higher voltage is applied to the same motor winding during the same driving phase just prior to and substantially until the time that the winding is de-energized.