Developing unit

A developing unit, comprising:

• a case for accommodating toner;
• a developing roller rotatably supported by said case through a first shaft;
• a supply roller rotatably supported by said case through a second shaft and formed by an elastic member arranged to be pressed against said developing roller in such a manner as to supply toner to the surface of said developing roller;
• a first sealing member disposed on a side of said developing roller and on a side of said supply roller so as to prevent leakage of toner from said first and second shafts to the outside portion of said case;
• and
• a second sealing member in the form of a film, arranged to be pressed against the lower surface of said developing roller in order to prevent leakage of toner to an outside portion of said case, wherein
• said second sealing member is allowed to abut against said developing roller, and a quantity δ of displacement of said second sealing member occurring due to the abutment of said second sealing member against said developing roller satisfies 0.1 mm<δ<0.8 mm.

A developing unit, comprising:

• a case for accommodating toner;
• a developing roller rotatably supported by said case through a first shaft;
• a supply roller rotatably supported by said case through a second shaft and formed by an elastic member arranged to be pressed against said developing roller in such a manner as to supply toner to the surface of said developing roller;
• and
• a first sealing member disposed on a side of said developing roller and on a side of said supply roller so as to prevent leakage of toner from said first and second shafts to the outside portion of said case, wherein said developing roller includes end portions for conveying toner, and wherein said ends are chamfered, and a quantity of elastic deformation of said first sealing member is larger than an amount of chamfering of said end portions.