Sheet thickness measuring device and image forming apparatus

A sheet thickness measuring device comprising:

• an illumination unit that outputs a light that is illuminated on one of faces of a stack of sheets having a top face, a bottom face, and side faces;
• a detection unit that detects a light amount distribution of light reached to one of side faces of the stack of sheets, the side face being different from the face where the illumination unit illuminates the light;
• and
• a calculation unit that calculates a thickness of a sheet in the stack of sheets based on the light amount distribution detected by the detection unit.

A sheet thickness measuring device comprising:

• an illumination unit that outputs a light that is illuminated on one of side faces of a stack of sheets having a top face, a bottom face, and the side faces;
• a detection unit that detects a light amount distribution of light reached to the side face on which the illumination unit illuminates the light;
• a light shield that prevents the light illuminated by the illumination unit from reaching the detection unit without entering into the stack of sheets;
• and
• a calculation unit that calculates a thickness of a sheet in the stack of sheets based on the light amount distribution detected by the detection unit.