Transparency sheet edge detector system using edge shadow sensing
AssigneeXerox Corporation
InventorThomas Acquaviva
Life of this patent
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Abstract
A dual mode non-contact optical sheet edge detection system for detecting either fully transparent or regular sheets being fed in a sheet transport path of a reproduction system, with an illumination source for illuminating the potential sheet edge area at an angle to generate a detectable sheet edge shadow from transparent sheets, and an optical detection system remotely detecting the generated edge shadow to provide sheet edge location or timing information to a control system. Preferably the sheet edge is held spaced above the illuminated sensor an illuminated sensor target area to enhance the shadow effect.
Claims8
A dual mode non-contact optical sheet detection system for detecting at least one sheet edge of either fully transparent or opaque paper image substrate sheets in a sheet transport path of an image reproduction apparatus, comprising:
- an illumination source for illuminating the surface of either a transparent or opaque sheet moving in said sheet transport path at a sufficiently shallow illumination angle to the surface of said sheet to generate a detectable edge shadow directly adjacent to said sheet edge from either a transparent or opaque sheet,
- said illumination angle being substantially greater than a grazing angle to not form shadows from said surface of said sheet.
- and an optical detection system positioned to remotely detect in said sheet transport path said detectable edge shadow of said sheet without contacting said sheet,
- said optical detection system providing a control signal corresponding to said sheet edge passing said optical detection system,
- further including a spacer associated with said sheet transport path for spacing said sheet edge from said optical target area to enhance said generated edge shadow.
A dual mode non-contact optical sheet detection system for detecting at least one sheet edge of either fully transparent or opaque paper image substrate sheets in a sheet transport path of an image reproduction apparatus, comprising:
- an illumination source for illuminating the surface of either a transparent or opaque sheet moving in said sheet transport path at a sufficiently shallow illumination angle to the surface of said sheet to generate a detectable edge shadow directly adjacent to said sheet edge from either a transparent or opaque sheet.
- said illumination angle being substantially greater than a grazing angle to not form shadows from said surface of said sheet,
- and an optical detection system positioned to remotely detect in said sheet transport path said detectable edge shadow of said sheet without contacting said sheet,
- said optical detection system providing a control signal corresponding to said sheet edge passing said optical detection system, wherein said sheet transport path includes lifting means for lifting a sheet in said sheet transport path by approximately 1 mm relative to said optical detection system to enhance said sheet edge shadow.
Dependencies are inferred from the claim text.