Reading device, image forming apparatus, and state detection method to detect a multi-feed state of an object using reflected light in a visible wavelength and an invisible wavelength and comparing reading value results to references associated with the invisible and visible wavelength reference values

A reading device comprising:

• an illuminator to illuminate an object to be read with light in an invisible wavelength range;
• an imager to capture an image of the light reflected from the object to be read, within the invisible wavelength range;
• and
• a memory to hold a reference value of the object to be read;
• and
• a detector to detect a state of the object to be read, based on a difference between a level of a reading value of an invisible image captured within the invisible wavelength range using the light reflected from the object which was captured by the imager and a level of the reference value,
• wherein the illuminator is to illuminate the object to be read with light in a visible wavelength range,
• wherein the imager is to capture an image of the light reflected from the object to be read, within the visible wavelength range,
• wherein the memory is to hold, as the reference value of the object to be read, a reference value corresponding to the invisible image and a reference value corresponding to a visible image captured within the visible wavelength range, and
• wherein the detector is to compare the level of the reading value of the invisible image with a level of the reference value corresponding to the invisible image and compare a level of a reading value of the visible image with a level of the reference value corresponding to the visible image, to detect the state of the object to be read,
• wherein the detector is to detect whether the state of the object to be read is a state of multi-feed.