Document sheet position detecting device for image forming apparatus
AssigneeRicoh Company, Ltd.
InventorKouichi Kamon
Life of this patent
Estimating the term…
Abstract
A document sheet position detecting device adapted to for image forming apparatus, such as digital copiers and facsimile. Apparatus image information on an original document are optically detected using a CCD or other type line sensor and the detected optical signals are converted into electric signals which are fed to a printer or like recording apparatus to reproduce the images. The device detects positional data of the document sheet in a separate operation from the detection of the image read out operation. An optical filter may be inserted during the position detecting operation. The sensor is adjusted for the difference in intensity caused by the filter.
Claims35
A document sheet position detecting device for optically detecting the extension of an image bearing document sheet by a raster scanning operation, comprising:
- a document sheet cover for pressing said document sheet onto a contact glass platen, said cover being colored by a certain predetermined color;
- illumination means for illuminating the surface of said image bearing document sheet;
- an optical system for passing light rays reflected by said surface of said image bearing document sheet;
- a photoelectric converter element for receiving light rays and for converting said light rays into electric signals;
- digital converter means for converting the outputs from said photoelectric converter element into digital signals;
- an optical filter for shielding light rays reflected by said document cover and for transmitting therethrough light rays reflected by the background of said image bearing document sheet during a document sheet position detecting operation, said optical filter being interposed in the optical path of the reflected light during the document sheet position detecting operation and retracted from the optical path of the reflected light during the normal image read-out operation;
- and
- data processing means for detecting at least one end of said image bearing document sheet by processing positional data fed from said photoelectric converter means, the positional data indicating said document sheet cover being differentiated from the positional data indicating the background of said image bearing document sheet by the difference in quantity of light rays reflected by said background of said image bearing document sheet and passing through said optical filter to be received by said photoelectric converter means.
Dependencies are inferred from the claim text.