Patent ID: 7157725

Claim:
A discrimination device for discriminating a type, from two types which differ in surface reflectivity, of a discrimination subject, the discrimination device comprising: a first optical sensor, the output of which switches to one of an ON state and an OFF state in accordance with presence of at least one of the two types of discrimination subject; a second optical sensor including a light detection portion which receives light reflected by the two types of discrimination subject, the output of the second optical sensor switching to one of an ON state and an OFF state in accordance with light reflected from, of the two types of discrimination subject, the type whose reflectivity is higher; and a third optical sensor including a light detection portion which receives light reflected by the two types of discrimination subject, the output of the third optical sensor switching to one of an ON state and an OFF state in accordance with light reflected from, of the two types of discrimination subject, the type whose reflectivity is lower.