Patent ID: 7233014

Claim:
A medium detection apparatus comprising: a light emitting section adapted to emit light; a light receiving section adapted to detect reflected light and output an output value in accordance with an amount of the reflected light; a medium supporting section adapted to support a medium and having a diffusing section adapted to diffuse the light emitted from said light emitting section; and a controller adapted to detect an edge of said medium based on a difference between the output value of said light receiving section when said light receiving section detects light reflected from said medium and the output value of said light receiving section when said light receiving section detects light reflected from said medium supporting section, wherein said medium supporting section has a contact surface that comes into contact with said medium, and a non-contact surface that does not come into contact with said medium, wherein said diffusing section is formed in said contact surface and said non-contact surface, wherein said diffusing section is formed by providing a depression and a protrusion on said contact surface and said non-contact surface; and wherein a difference in height of the depression and the protrusion of said diffusing section formed on said contact surface is larger than a difference in height of the depression and the protrusion of said diffusing section formed on said non-contact surface.