A layer-thickness regulating member includes a thin plate member and a projection member provided on a free edge portion of the thin plate member. A leak preventing members include a first seal member and a second seal member. The first seal member includes a first downstream portion disposed adjacent to the projection member on a front surface of the thin plate member, and a first upstream portion extending upstream of the first downstream portion. The second seal member includes a second downstream portion, and a second upstream portion which extends upstream of the second downstream portion. The second upstream portion includes a covered portion covered with the first upstream portion, an opposed portion disposed adjacent to the covered portion and opposed to the adjacent portion of the projection member and an exposed portion extending upstream of the covered portion and the opposed portion.