Image reading device, image forming apparatus, and method of setting white reference value

An image forming apparatus comprising:

• an image reading sensor which converts light from an imaging position into image data;
• a lighting unit in which an imaging position is irradiated with light;
• a white reference plate which has a reading range which is a white reference value;
• a controller which adjusts a light intensity of light which is emitted from the lighting unit, and sets a white reference value using a plurality of pixels of the white reference plate which are read using the image reading sensor, and causes an image on a face of the original document which passes through a predetermined reading position to be read using the image reading sensor;
• a signal processing unit which performs image processing of image data of the original document which is read using the image reading sensor based on the white reference value;
• an image forming unit which forms an image corresponding to the image data of the original document which was subjected to the image processing using the signal processing unit on a recording medium;
• and
• a memory which stores each read pixel of the white reference plate and a light intensity in association with each other,
• wherein the controller adjusts the light intensity based on information stored in the memory.

A method of setting a white reference value which is used when performing an image reading process, the method comprising:

• reading a plurality of portions in a reading range of a white reference plate using an image reading sensor;
• adjusting a light intensity of light which is emitted from a lighting unit, and
• setting a white reference value using image data which is read from the plurality of portions in the reading range of the white reference plate using the image reading sensor;
• and
• storing each read pixel of the white reference plate and a light intensity in association with each other,
• wherein adjusting the light intensity is based on information stored.