A method of modifying a toner hopper including a toner window and an end cap. The method including providing a slot on the end cap and applying a toner seal covering the toner window, the toner seal including a pull tab. The method further including applying an end seal to the toner hopper, the end seal providing a gap and placing the pull tab within the gap and the slot.

A remanufacturing method of a developing apparatus including: a communicating step of removing a part of a frame of the developing apparatus to form a communication hole such that an outside of the frame and a developing chamber of the frame are connected each other; a refilling step of refilling an inside of the frame with developer via the communication hole; and a sealing step of sealing the communication hole.

A method of modifying a toner hopper including a toner window and an end cap. The method including providing a slot on the end cap and applying a toner seal covering the toner window, the toner seal including a pull tab. The method further including applying an end seal to the toner hopper, the end seal providing a gap and placing the pull tab within the gap and the slot.

A developing device includes a developing container, a developing roller, a regulating blade, a seal member, and a resin member. The regulating blade includes a mounting plate and a blade plate. The developing container has a facing part facing a step part due to thickness difference between the mounting plate and the blade plate. The seal member has a resin placement area, and is squeezed between the regulating blade and the facing part. The resin placement area is an area that penetrates the seal member and is surrounded by the seal member. The resin placement area overlaps the step part.