An image sensor module includes an elongated light emitting unit, a photodetector, a lens unit, a substrate with the photodetector mounted on. The substrate is spaced apart from the lens unit in a thickness direction of the substrate. The image sensor module further includes a resin case provided with a light emitting unit chamber, a lens unit chamber and a substrate chamber. The lens unit chamber has a first bottom face extending in the first direction, and the substrate chamber has a second bottom face extending in the first direction and facing opposite to the first bottom face in the thickness direction of the substrate. The first or second bottom face is formed with at least one protrusion extending in the thickness direction of the substrate.

The image forming apparatus includes a sheet conveyance part, an image forming part, and a sheet reading unit. The sheet reading unit includes a line sensor. The line sensor includes split line sensors. The line sensor reads a conveyed sheet. The line sensor includes a plurality of split line sensors. The split line sensors are placed at non-stretching positions, respectively. Each non-stretching position is such a position that as in the main scanning direction, a main-scanning-direction distance from a gap between one split line sensor and another split line sensor to an ideal edge position of every usable regular size exceeds a permissible value.

An exposure device includes: a first light emitting element; a first lens array that converges light emitted from the first light emitting element; a second light emitting element; a second lens array that converges light emitted from the second light emitting element; a holder that holds the first light emitting element, the first lens array, the second light emitting element, and the second lens array; and a first adjustment mechanism that is provided in the holder and adjusts a first distance between the first lens array and the first light emitting element.

A controller of an image reading apparatus is configured to cause the reading device to read an image on an original with moving a reading location from a first position to a second position, after reading the image on the original with moving the reading location from a third position to the first position, the third position being a position between the first position and the second position and spaced from the first position by a particular distance and determining a width of the original in the main scanning direction. The controller is configured to further move the reading location from the second position to the first position, and detect an instruction to continue reading a subsequent original during a period before the reading location reaches the third position. When the instruction is detected, the controller stops moving the reading location when it reaches the third position.

A reading apparatus that reads a sheet includes: a first light emitting diode (LED) configured to emit light with a specific wavelength; a light emitting element including a second LED configured to emit light with the specific wavelength and a phosphor configured to be excited by the light emitted from the second LED; a line sensor configured to generate a reference signal according to a quantity of received light emitted from the first LED and reflected off the sheet, and also generate an image signal according to a quantity of received light emitted from the light emitting element and reflected off the sheet; and a controller configured to generate an image representing the sheet from a differential result obtained by removing a component corresponding to the reference signal from the image signal.

A first lens body and a second lens body are fixed to, using an adhesive layer, a surface of a lens fixing plate determined by intersection of a straight line in an optical axis direction and a straight line in a longitudinal direction, such that the lens fixing plate in which a lens fixing plate opening is formed in a lateral direction overlaps, when viewed in the lateral direction, at least a portion of a junction at which the first lens body and the second lens body are bonded to each other. A first adjustment member is brought into contact with the first lens body via at least one hole into which the first adjustment member is inserted A second adjustment member is brought into contact with the second lens body via at least one hole and into which the second adjustment member is inserted.

The lens unit includes a first lens array including a plurality of first lens elements each of which has a first optical axis and which are arranged in an arrangement direction perpendicular to the first optical axis. A second lens array includes a plurality of second lens elements each of which has a second optical axis and which are arranged in the arrangement direction while facing the first lens elements. The second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about a virtual line perpendicular to both the first optical axis and the arrangement direction as the rotational axis by 180 degrees. The optical axes of the lens elements located at the substantially centers of the lens arrays in the arrangement direction are arranged to substantially coincide with each other.

A reflective member is disposed on the optical path from the linear light source to the lens array. An ultraviolet light blocking filter is provided closer to a light-receiving unit than the reflective member. A color filter is provided closer to the light-receiving unit than the ultraviolet light blocking filter. A light-receiving surface of the light-receiving unit has a first region opposed to the reflective member without the ultraviolet light blocking filter and the color filter interposed therebetween, a second region opposed to the reflective member and the ultraviolet light blocking filter without the color filter interposed therebetween, and a third region opposed to the reflective member, the ultraviolet light blocking filter, and the color filter.

An image reading device can easily increase or improve the depth of field. The image reading device includes a lens array (1) including lenses (2) arrayed in a main scanning direction, a sensor array (4) including sensor elements (4) arrayed in the main scanning direction to receive light converged by the lenses (2), and an overlap preventer located between the lens array (1) and the sensor array (4) to prevent an overlap of images formed by the lenses (2). The overlap preventer includes a slit assembly (5) including at least one specific-light blocker or optically transparent columns (13).

An image reading apparatus acquires first image data of a background portion stored in advance and read by a reading unit, acquires second image data by reading the background portion, generates third image data by increasing resolution of the first image data and fourth image data by increasing resolution of the second image data, detects an amount of shift of an image sensor relative to a lens array in a predetermined direction by shifting a specific pixel range of the fourth image data relative to the third image data and comparing the specific pixel range with the third image data, and compares fifth image data obtained by shifting the fourth image data in accordance with the shift amount with the third image data, so as to determine whether each of pixels included in the fifth image data is a defective pixel having an abnormal value.