Patent ID: 7813010
Filing Date: 2010-10-12
Classification: G03G,H04N

Abstract:
1. A document reading apparatus comprising: an illuminating light that illuminates a document; a driving unit that drives the illuminating light in a sub-scanning direction; an image pick-up device that reads the document in a main-scanning direction that is perpendicular to the sub-scanning direction, and outputs image signals; an optical unit that projects an image of the document illuminated by the illuminating light onto the image pick-up device; an image-signal extracting unit that extracts image signals at a plurality of points in the main-scanning direction of a first position and a second position in the sub-scanning direction, from among the image signals output, the first position and the second position being different in the sub-scanning direction; a document detecting unit that creates binary data indicating a presence of the document at each of the points, based on the image signals extracted; and a size detecting unit that: the second position in the main-scanning direction, if the binary data for the second position satisfies the condition; a light transmitting plate; a platen for pressing the document toward the light transmitting plate; an opening-status detecting unit that detects whether the platen is opened at an angle equal to or larger than a preset opening angle or closed at an angle equal to or less than the preset opening angle; a read control unit that drives the illuminating light forward to a first return position in the sub-scanning direction, which is within a document placing area on the light transmitting plate, in response to a change from “close” to “open” as a result of detection by the opening-status detecting unit, and lights up the illuminating light and drives the illuminating light backward, in response to a change from “open” to “close” as a detection result by the opening-status detecting unit, wherein a light transmitting window that is illuminated by the illuminating light at the standby position; and a document shifting unit that shifts a sheet-type document to pass the light transmitting window in the sub-scanning direction, wherein the read control unit selectively executes either one of a sheet-through read mode in which the illuminating light is fixed at the standby position and the image of the sheet-type document shifted is read, and a flatbed read mode in which the illuminating light is driven in the sub-scanning direction along the light transmitting plate, and wherein the read control unit executes the flatbed read mode, when the document-placement detecting unit has not detected the presence of a document at the time of receiving the document read instruction.