Image forming apparatus

An image forming apparatus, comprising:

• an image forming device to form an image on a printing medium;
• a belt member movable to circulate, the belt member including plural suction holes to attract the printing medium onto the belt member;
• a reflection-type photosensor to detect the printing medium on the belt member;
• and
• a reflection member to reflect light from the reflection-type photosensor through the suction holes, the reflection member disposed inside the belt member,
• wherein whether or not a transparent printing medium is present on the belt member is determined by comparing a sensor output of the reflection-type photosensor with a predetermined reference value of presence and absence of the printing medium, and
• wherein the reflection member has a reflection rate at which, when the reflection-type photosensor receives reflection light at positions of the suction holes with the transparent printing medium being not present on the belt member, the sensor output of the reflection-type photosensor is lower than the predetermined reference value, and
• when the reflection-type photosensor receives reflection light at the positions of the suction holes with the transparent printing medium being present on the belt member, the sensor output of the reflection-type photosensor is equal to or greater than the predetermined reference value.