Colorimetry apparatus and image forming apparatus

An image forming apparatus comprising:

• an image forming unit configured to form an image on a recording material;
• a fixing unit configured to fix an unfixed image on the recording material on which the image is formed;
• a reversing unit configured to reverse the recording material having the fixed image;
• a double-sided conveyance unit configured to convey the recording material whose orientation is reversed by the reversing unit;
• a colorimetry apparatus including:
• (1) a light emitting source configured to emit light to a surface of the recording material having the fixed image;
• (2) a spectral unit configured to disperse reflected light reflected on the surface of the recording material having the fixed image;
• (3) a light receiving device configured to (a) receive dispersed light dispersed by the spectral unit and (b) output signals regarding color components of the dispersed light dispersed by the spectral unit;
• and (4) a common electronic circuit substrate on which a circuit is provided, wherein the circuit is configured to control the light emitted from the light emitting source and to process the signals regarding color components, the signals being output from the light receiving device;
• and
• a first controller configured to control an image forming condition of the image forming unit based on an output of the colorimetry apparatus,
• wherein the colorimetry apparatus is positioned at a location to measure the recording material having the fixed image, conveyed by the double-sided conveyance unit, and
• wherein the light emitting source and the light receiving device are mounted on a common surface of the common electronic circuit substrate.