Image reading apparatus

An image reading apparatus having a plate-shaped transparent member for receiving a document to be optically scanned by a photoelectric transducer having a plurality of photoelectric transducing elements such that the image recorded on the document is read, comprising:

• a scanning device movable in a direction orthogonal to said photoelectric transducer, said scanning device irradiating light from a lamp and reflected by reflecting mirrors, to said photoelectric transducer;
• a size detector for determining the size of a document disposed on said transparent member, on the basis of pixel signals outputted from the photoelectric transducing elements within a plurality of small regions that extend across specific edges of each of a plurality of documents of different sizes, the photoelectric transducing elements being disposed at substantially fixed positions on said transparent member,
• wherein at least some of said plurality of small regions include a pair of smaller regions corresponding to a pair of areas spanning specific edges of said document of a predetermined size at a predetermined interval, and
• the position of the edge of said document and the size of said document are determined on the basis of whether levels of signals outputted from the photoelectric transducing elements within said smaller regions are greater than or equal to a predetermined value;
• and
• a control portion connected to said scanning device and said size detector so as to control said scanning device.

An image reading apparatus having a plate-shaped transparent member for receiving a document to be optically scanned by a photoelectric transducer having a plurality of photoelectric transducing elements such that the image recorded on the document is read, comprising:

• a scanning device movable in a direction orthogonal to said photoelectric transducer, said scanning device irradiating light from a lamp and reflected by reflecting mirrors, to said photoelectric transducer;
• a size detector for determining the size of a document disposed on said transparent member, on the basis of pixel signals outputted from the photoelectric transducing elements within a plurality of small regions that extend across specific edges of each of a plurality of documents of different sizes, the photoelectric transducing elements being disposed at substantially fixed positions on said transparent member,
• wherein at least some of said plurality of small regions include smaller regions which correspond to the area continuously spanning specific edges of said document of a predetermined size, and
• the position of the edge of said document and the size of said document are determined on the basis of the change in levels of signals outputted from the photoelectric transducing elements within said smaller regions;
• and
• a control portion connected to said scanning device and said size detector so as to control said scanning device.

An image reading apparatus having a plate-shaped transparent member for receiving a document to be optically scanned by a photoelectric transducer having a plurality of photoelectric transducing elements such that the image recorded on the document is read, comprising:

• a scanning device movable in a direction orthogonal to said photoelectric transducer, said scanning device irradiating light from a lamp and reflected by reflecting mirrors, to said photoelectric transducer;
• a size detector for determining the size of a document disposed on said transparent member, on the basis of pixel signals outputted from the photoelectric transducing elements within a plurality of small regions that extend across specific edges of each of a plurality of documents of different sizes, the photoelectric transducing elements being disposed at substantially fixed positions on said transparent member,
• a control portion connected to said scanning device and said size detector so as to control said scanning device;
• and
• a cover movable between a position at which said transparent member is shielded and a position at which said transparent member is exposed, wherein before and after said transparent member is shielded by said cover, the size of said document is determined on the basis of the signals outputted from the photoelectric transducing elements.

An image reading apparatus in which a document, which is disposed on a plate-shaped transparent member, is optically scanned by a photoelectric transducer having a plurality of photoelectric transducing elements such that the image which is recorded onto said document is read, comprising:

• a size detector which determines the size of said document which is disposed on said transparent member, on the basis of pixel signals outputted from the photoelectric transducing elements within a plurality of small regions which correspond to the area across each specific edge of a plurality of documents of different sizes which are disposed at substantially fixed positions on said transparent member;
• and
• detection means which detects the existence of said document at a predetermined position on said transparent member wherein when said document is disposed on said transparent member in a first direction, said document exists regardless of the size of said document, and when said document is disposed on said transparent member in a second direction which is different from said first position, said document does not exist regardless of the size of said document,
• wherein on the basis of the signals outputted from the photoelectric transducing elements within said plurality of small regions and the results of detection of existence of said document effected by said detection means, the size and direction of said document disposed on said transparent member are determined.