US Patent 7588309 Image forming apparatus

Cleaning liquid stored in a first storage tank is absorbed by a sponge via a passage formed in a tube and a holder, and then applied onto a conveyance belt when the sponge comes into contact with the conveyance belt. Here, even when air bubbles enter into the cleaning liquid supplied to the sponge, the air bubbles are discharged to the outside through an air discharging hole formed in the holder.