DEVICE FOR MEASURING THE REMAINED TONER AND IMAGE FORMING APPARATUS HAVING THE SAME

摘要

A device for measuring the remaining toner and a developing apparatus having the same are provided to improve the accuracy in measurement of the remaining toner by forming protrusions on an exit surface of a first light path member and an incidence surface of a second light path member so as to effectively clean the exit surface and the incidence surface. A device for measuring the remaining toner comprises a light emitting element(10), a light receiving element(20), a first light path member(40), and a second light path member(50) distanced from each other. The first light path member and the second light path member form a light path so that the light emitted from the light emitting element is incident onto the light receiving element through an inside of a developer case(30). A plurality of hemisphere-shaped protrusions(41a,51a) are respectively formed on an exit surface(41) of the first light path member and an incidence surface(51) of the second light path member.