Method for determining type of sheet by imaging sheet

A light guide comprising:

• a first light guide portion configured to guide first light in a first light guiding path, the first light being of light irradiated from a light source to an irradiation target body;
• and
• a second light guide portion configured to guide second light in a second light guiding path different from the first light guiding path, the second light being of the light irradiated from the light source and different from the first light,
• wherein the first light guide portion includes at least one reflection surface configured to cause a portion of the first light guiding path to be bent,
• wherein the first light guide portion includes:
• a first incidence surface that faces the light source,
• a first deflection surface configured to deflect the first light incident on the first light guide portion through the first incidence surface,
• a second deflection surface configured to deflect the first light deflected by the first deflection surface,
• a first emission surface that is disposed facing the irradiation target body and emits the light deflected by the second deflection surface to the irradiation target body,
• a second incidence surface, which is disposed to face the irradiation target body and on which reflected light from the irradiation target body is incident, and
• a second emission surface configured to emit the reflected light incident on the first light guide portion through the second incidence surface.

A light guide comprising:

• a first light guide portion configured to guide first light in a first light guiding path, the first light being of light irradiated from a light source to an irradiation target body;
• and
• a second light guide portion configured to guide second light in a second light guiding path different from the first light guiding path, the second light being of the light irradiated from the light source and different from the first light,
• wherein the first light guide portion includes at least one reflection surface configured to cause a portion of the first light guiding path to be bent,
• the second light guide portion includes:
• an incidence surface that faces the light source,
• a first deflection surface configured to deflect the second light incident on the second light guide through the incidence surface,
• a second deflection surface configured to deflect the second light deflected by the first deflection surface, and
• an emission surface configured to emit the light deflected by the second deflection surface towards a detection portion.