Developing device and image forming apparatus having the same
A developing device is provided that facilitates developing agent delivery upward. A cartridge includes a developing roller, a supply roller, and a container disposed below the supply roller. The container can have an upper portion formed with an opening having upper and lower edges. A conveying member can be rotatably disposed in and in rotational contact with an inner surface of the container for delivering the developing agent upward. The developing agent container can include a first wall portion for receiving developing agent through the opening. The first wall portion extends from the lower edge in a downstream direction with respect to a rotational direction of the conveying member toward a bottommost portion of the supply roller. The container also includes a second wall portion extending from the upper edge in an upstream direction. The conveying member can be in simultaneous sliding contact with the first and second wall portions.
1. A developing device comprising:
a developing member having an outer surface on which a developing agent is carried;
a supply member disposed below the developing member for supplying the developing agent to the outer surface, the supply member having a bottommost portion;
a developing agent container disposed below the supply member and having an inner surface defining an internal space for accommodating the developing agent, the developing agent container having an upper portion formed with an elongated opening having an elongated first edge and an elongated second edge extending along the first edge; and
a conveying member rotatably disposed in the internal space and in rotational contact with the inner surface for conveying the developing agent upward, the developing agent container including a first wall portion for receiving thereon the developing agent passed through the opening, the first wall portion extending from the first edge in a downstream direction with respect to a rotational direction of the conveying member toward a position close to the bottommost portion, the developing agent container also including a second wall portion extending from the second edge in an upstream direction with respect to the rotational direction, and the conveying member being in simultaneous sliding contact with both the first wall portion and the second wall portion for conveying the developing agent onto the first wall portion,
wherein the first edge is a lower edge of the opening, and the second edge is an upper edge of the opening.
2. The developing device as claimed in claim 1 , wherein the lower edge is positioned higher than the bottommost portion and, the first wall portion obliquely extends downward from the lower edge toward a position immediately below the supply member.
3. The developing device as claimed in claim 1 , wherein the upper edge is positioned upstream of the lower edge in the rotational direction.
4. The developing device as claimed in claim 1 , wherein the upper edge is positioned downstream of the lower edge in the rotational direction.
5. The developing device as claimed in claim 1 , wherein the conveying member comprises:
a rotation shaft rotatably supported to the developing agent container; and
an agitation film having a base end fixed to the rotation shaft and a free end in sliding contact with the inner surface in a flexed fashion.
6. The developing device as claimed in claim 5 , wherein the agitation film is split into a central first section positioned at a longitudinally center portion of the rotation shaft, and a pair of second sections positioned at longitudinally end portions thereof, the pair of second sections having radial lengths in a radial direction of the rotation shaft greater than that of the first section.
7. The developing device as claimed in claim 6 , wherein the pair of second sections have free ends slanted in such a manner that a radial length of the second sections is gradually reduced toward the longitudinally endmost portions thereof.
8. An image forming apparatus comprising:
a frame;
a plurality of photosensitive members;
an intermediate transfer belt; and
a plurality of developing devices as claimed in claim 1 , each of the plurality of photosensitive members and each of the plurality of developing devices being disposed immediately below the intermediate transfer belt.