Image reading device, image forming apparatus, and image reading method

An image reading device that reads image information by irradiating an illuminating light onto a document by an illumination unit and converting a reflected light from the document surface to an electric signal by a photoelectric transducer, wherein

• the illumination unit includes a plurality of light emitting diodes (LEDs), a light guide member that guides an illuminating light emitted by the LEDs toward a surfaced of the document, and an infrared-cut unit that cuts a light having a wavelength in an infrared region from the illuminating light emitted by the light guide member.

An image reading device that reads image information by irradiating an illuminating light onto a document by an illumination unit and converting a reflected light from a surface of the document to an electric signal by a photoelectric transducer, wherein

• the illumination unit includes a plurality of light emitting diodes (LEDs) that emit only a light having a wavelength shorter than a wavelength in an infrared region.

An image forming apparatus comprising an image reading device that reads image information by irradiating an illuminating light onto a document by an illumination unit and converting a reflected light from a surface of the document to an electric signal by a photoelectric transducer, wherein

• the illumination unit includes a plurality of light emitting diodes (LED) and an infrared-cut unit that cuts a light having a wavelength in an infrared region from the illuminating light emitted by the LEDs.

An image forming apparatus comprising an image reading device that reads image information by irradiating an illuminating light onto a document by an illumination unit and converting a reflected light from a surface of the document to an electric signal by a photoelectric transducer, wherein

• the illumination unit includes LEDs, a light guide member that guides an illuminating light emitted by the LEDs toward the document surface, and an infrared-cut unit that cuts a light having a wavelength in an infrared region from the illuminating light emitted by the light guide member.

An image forming apparatus comprising an image reading device that reads image information by irradiating an illuminating light onto a document by an illumination unit and converting a reflected light from a surface of the document to an electric signal by a photoelectric transducer, wherein

• the illumination unit includes LEDs that emit only a light having a wavelength shorter than a wavelength in an infrared region.

An image reading method applied to read image information by irradiating an illuminating light onto a document and converting a reflected light from a document surface to an electric signal by a photoelectric transducer, the method comprising:

• irradiating onto a surface of the document an illuminating light whose light component in an infrared region out of the visible light spectrum has been reduced to an intensity sufficiently low relative to a sensitivity of the photoelectric transducer, and
• reading the reflected light from the surface of the document.