Gear Toshiba e-studio 45

Question

Sorry, I forgot to tell what portion is the gear can be found. The gear that I was talking about is the small gear in the developer with 21 teeths. It has worn-out in a month time. Do you think there is a problem that causes it to worn-out easily.

We clean the parts where the corona wire is placed which is near the drum. It also have a screen which always darkens. If this portion darkens the copy will blacken also so what we do is to clean it from time to time.

Thanks for the help again.