Modulator for doubling resolution in the fast-scan direction for a laser imager in an electrophotographic printer

A modulator circuit for use in driving a laser in an electrophotographic laser printer starts with a standard, inexpensive low-frequency pixel clock for timing the modulation of the laser to form an image, and effectively doubles the modulation frequency, thereby allowing spatial resolution to be doubled in the fast-scan direction. An original, low-frequency pixel clock is split, one of the split signals is delayed by a predetermined amount, and the original and delayed pixel clocks are applied to an exclusive OR gate. The modulator of the present invention functions without either a high-frequency original pixel clock or a phase-locked loop.