Patent ID: 8630560

Claim:
A printing apparatus which prints an image on a recording medium, comprising: an image forming section which forms a toner image of the image to be printed on the recording medium; a transport belt which transports the toner image formed by the image forming section; a light-emitting section which emits a light to the transport belt; a first light-receiving section which is disposed at a position through which a regular reflection light, of the light emitted from the light-emitting section, reflected from the transport belt passes; a second light-receiving section which is disposed at a position different from the position of the first light-receiving section; a transmissive member which is disposed at a position through which the light emitted from the light-emitting section to the transport belt and a reflection light, of the light, reflected from the transport belt pass and which transmits the light and the reflection light; and a judgment section which calculates a first ratio which is a ratio of a light-receiving amount of the first light-receiving section to a light-emitting amount of the light-emitting section and a second ratio which is a ratio of a light-receiving amount of the second light-receiving section to the light-emitting amount of the light-emitting section, and the judgment section judges whether or not the transmissive member is contaminated based on the first ratio and the second ratio.