ROS printer incorporating a variable wavelength laser
AssigneeXerox Corporation
InventorJohn R. Andrews
Life of this patent
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Abstract
A fully electronic, nonmechanical raster output scanner (ROS) digital printer for high resolution xerographic printing is enabled by combining a laser adapted to produce a variable wavelength output with a dispersive element such as a grating to present a raster scan at an image plane. In a preferred embodiment, a diode laser is positioned within a laser cavity whose length is designed as a function of the resolution required for the scanned image. The wavelength varying output is incident upon a high resolution grating which diffracts the radiation through a diffraction angle which varies according to the wavelength of the incident light. A scan lens is positioned between the grating and a photoreceptor surface to provide focusing and scan linearity correction to the scan line.
Claims4
A digital scanning laser printer for forming high resolution scan lines at a photosensitive image medium comprising:
- a broad-band wavelength tunable laser source operational in a plurality of longitudinal modes to provide a beam of radiation whose wavelength varies incrementally over the tunable range,
- a high resolution diffraction grating in the path of said output radiation beam, wherein the radiation beam is incident to the grating at an angle .alpha. measured normal to the grating, said grating diffracting said output beam of radiation through an angle .beta. the magnitude of .beta. being determined by the wavelength of said beam of radiation, to produce an output beam which scans across a diffraction angle, and
- a scan lens positioned between the photosensitive imaging medium and the grating, said scan lens focusing the diffracted beam onto the image medium as a linearized scan line comprising a plurality of neighboring pixels with uniform inter-pixel spacing corrected for distortion and spot size variations.
Dependencies are inferred from the claim text.