Imaging apparatus with variable aperture platen

Imaging apparatus comprising:

• a light transparent platen for holding an original document which may be smaller than the platen;
• a light source for illuminating the platen to expose a document on the platen;
• actuatable means for selectively inhibiting the transmittance of light through that portion of the platen not covered by a document;
• a light-blocking cover for the platen, said cover being movable between an operative, light blocking position and a non-use position;
• means, responsive to movement of said cover to its non-use position for actuating said light inhibiting means;
• document recognition means for detecting the outline of the original document on the exposure platen;
• and
• means responsive to said document recognition means for controlling actuation of said light inhibiting means.

Imaging apparatus comprising:

• a light transparent platen for holding an original document which may be smaller than the platen;
• a light source for illuminating the platen to expose a document on the platen;
• actuatable means for selectively inhibiting the transmittance of light through that portion of the platen not covered by a document, wherein said light inhibiting means includes a liquid crystalline cell having a pair of opposed plates, a grid of transparent electrodes interposed between said pair of plates, and a layer of crystalline material interposed between said pair of plates contacting said grid;
• a light-blocking cover for the platen, said cover being movable between an operative, light blocking position and a non-use position;
• and
• means, responsive to movement of said cover to its non-use position for actuating said light inhibiting means.

Imaging apparatus comprising:

• a light transparent platen for holding an original document which may be smaller than the platen;
• a light source for illuminating the platen to expose a document on the platen;
• selectively operable means for rendering that portion of the platen not covered by a document substantially opaque;
• a light-blocking cover for the platen, said cover being movable between an operative, light blocking position and a non-use position;
• and
• means, responsive to movement of said cover to its non-use position for actuating said rendering means.

Imaging apparatus comprising:

• a light transparent platen for holding an original document which may be smaller than the platen;
• a light source for illuminating the platen to expose a document on the platen;
• selectively operable means for rendering that portion of the platen not covered by a document substantially opaque;
• document recognition means for detecting the outline of the original document on the exposure platen;
• a light-blocking cover for the platen, said cover being movable between an operative, light blocking position and a non-use position;
• means, responsive to movement of said cover to its non-use position for actuating said light rendering means;
• and
• means responsive to said document recognition means for controlling actuation of said rendering means.

Imaging apparatus comprising

• a light transparent platen for holding an original document which may be smaller than the platen;
• a light source for illuminating the platen to expose a document on the platen;
• selectively operable means for rendering that portion of the platen not covered by a document substantially opaque, wherein said rendering means includes a liquid crystalline cell having a pair of opposed plates, a grid of transparent electrodes interposed between said pair of plates, and a layer of crystalline material interposed between said pair of plates contacting said grid;
• a light-blocking cover for the platen, said cover being movable between an operative, light blocking position and a non-use position;
• and
• means, responsive to movement of said cover to its non-use position for actuating said light rendering means.