A scanning device includes a casing holding a original document table. A facing area is provided to the casing, and a rectangular hole is formed on the facing area. The rectangular hole has edges extending along a main scanning direction and edges extending along a sub-scanning direction. The edges extending along the sub-scanning direction are located in a central area of a photoelectric conversion element row of a sensor assembly in the main scanning direction. The sensor assembly scans the rectangular hole and detects a edge extending along the main scanning direction and a edge extending along the sub-scanning direction, thereby determines a scanning start position.

An image forming apparatus includes a fixing unit, an image reading unit, and a control unit. The fixing unit includes a first roller, a second roller, and a displacement mechanism that displaces at least one of the first roller and the second roller to form a nip portion. The image reading unit includes a scanning mechanism that scans by moving a carriage where a light source is mounted. The control unit executes a driving of the scanning mechanism and a driving of the displacement mechanism at different times.

In a reading device, a light transmissive member has a front surface on which an original is placed. A peripheral member is adjacent to the light transmissive member, and includes a back surface in which a reference hole is formed. The reference hole includes a first edge and a second edge intersecting with each other. A reading sensor faces the back surface of the light transmissive member and the back surface of the peripheral member. The controller controls the reading sensor to read a reading range including the reference hole to obtain a read image, and determines a reference position in the reading range based on the read image. The reference position is determined to an intersection between the first edge and the second edge. The controller sets a reading start position based on the reference position.

A rod lens array 10a includes a plurality of gradient-index rod lenses 1b arrayed to have optical axes parallel to each other, and forms an erecting equal-magnification image. The gradient-index rod lenses 1b each have a refractive-index distribution in a radial direction thereof. The refractive-index distribution n(r) is approximated by n(r)=n.sub.0⋅{1-(A/2)⋅r.sup.2}, where a refractive index at a center of the gradient-index rod lens 1b is represented by n.sub.0, a refractive-index distribution constant of the gradient-index rod lens 1b is represented by \A, and a distance from the center of the gradient-index rod lens 1b is represented by r. The gradient-index rod lens 1b has an aperture angle θ of 3 to 6°, the aperture angle θ represented by θ=sin.sup.−1(n.sub.0\A⋅r.sub.0), where a radius of the gradient-index rod lens is represented by r.sub.0. The rod lens array 10a has an imaging distance of 45 to 75 mm and a depth of field of 1.5 to 3.0 mm with value of modulation transfer function (MTF) of 30% or more at a spatial frequency of 6 Ip/mm.

An image scanning apparatus, and a method and an apparatus for controlling receiving of an image scanning optical signal are provided. The mage scanning apparatus may include an array photosensitive pixel unit configured to receive at least one optical signal, and a control circuit connected with the array photosensitive pixel unit and configured to control the array photosensitive pixel unit to receive the at least one optical signal. With the adoption of the image scanning apparatus, and the method and the apparatus for controlling receiving of the image scanning optical signal, the problem in the related art that an image is easily interfered by external stray lights within a non-exposure time of a scanning period and accordingly quality of a scanned image is reduced may be solved.

An image scanning apparatus, and a method and an apparatus for controlling receiving of an image scanning optical signal are provided. The mage scanning apparatus may include an array photosensitive pixel unit configured to receive at least one optical signal, and a control circuit connected with the array photosensitive pixel unit and configured to control the array photosensitive pixel unit to receive the at least one optical signal. With the adoption of the image scanning apparatus, and the method and the apparatus for controlling receiving of the image scanning optical signal, the problem in the related art that an image is easily interfered by external stray lights within a non-exposure time of a scanning period and accordingly quality of a scanned image is reduced may be solved.

In a reading device, a light transmissive member has a front surface on which an original is placed. A peripheral member is adjacent to the light transmissive member, and includes a back surface in which a reference hole is formed. The reference hole includes a first edge and a second edge intersecting with each other. A reading sensor faces the back surface of the light transmissive member and the back surface of the peripheral member. The controller controls the reading sensor to read a reading range including the reference hole to obtain a read image, and determines a reference position in the reading range based on the read image. The reference position is determined to an intersection between the first edge and the second edge. The controller sets a reading start position based on the reference position.

An image scanner includes a transparent plate, a scanning device, a driving device, a positioning member, a light absorbing portion and a white reference portion. The transparent plate has an original placing surface. The scanning device irradiates an original with light by means of a light source and scans reflected light from the original. The driving device reciprocates the scanning device along the transparent plate. The positioning member positions the original placed on the original placing surface of the transparent plate. The light absorbing portion, which is disposed on the original placing surface side of the positioning member and at substantially a central portion of the positioning member in moving directions of the scanning device, absorbs ambient light entering to the original placing surface side of the positioning member through the transparent plate. The white reference portion is provided to the original placing surface side of the positioning member.

An image reading device includes a first unit to read one surface of a document in a first area facing a document path, a second unit disposed in the first area to read the other surface of the document, a first reference member facing the first unit at a first distance therefrom at a second position in a second area not facing the path, a second reference member facing the first unit at a second distance therefrom at a first position in the first area, a third reference member facing the second unit at the second distance therefrom, and a correction unit to correct, based on a difference between first data generated through reading of the first member by the first unit and second data generated through reading of the second member by the first unit, third data generated through reading of the third member by the second unit.

A scanning device includes a casing holding a original document table. A facing area is provided to the casing, and a rectangular hole is formed on the facing area. The rectangular hole has edges extending along a main scanning direction and edges extending along a sub-scanning direction. The edges extending along the sub-scanning direction are located in a central area of a photoelectric conversion element row of a sensor assembly in the main scanning direction. The sensor assembly scans the rectangular hole and detects a edge extending along the main scanning direction and a edge extending along the sub-scanning direction, thereby determines a scanning start position.