Developer conveying device including a plurality of planar portions and a developing device and image forming apparatus provided with same

A developing device, comprising;

• a housing with a pair of wall portions;
• a developer conveyance path extending between the pair of wall portions;
• a conveying member rotatably supported on the wall portions and configured to convey developer from one wall portion to the other;
• and
• a developing roller rotatably supported in the housing and configured to carry the developer;
• wherein the conveying member includes:
• a spiral member having opposite first and second end parts and being formed by connecting spiral pieces, each of the spiral pieces forming one spiral turn, in a conveying direction of the developer and including a hollow interior formed by the connected spiral pieces;
• an inner wall portion including a plurality of planar portions which define the hollow interior of the spiral member and are connected at predetermined angles in a circumferential direction of the rotation of the conveying member in a cross-section intersecting an axial direction of the conveying member, the planar portions constituting inner surfaces of the spiral pieces;
• first and second shaft portions arranged respectively at the opposite first and second end parts of the spiral member, rotatably supported on the wall portions and serving as a rotary shaft for the rotation of the conveying member;
• the hollow interior is formed between the first and second shaft portions;
• and
• the conveying member has no other shaft part in the hollow interior.

An image forming apparatus, comprising:

• a housing with a pair of wall portions;
• a developer conveyance path extending between the pair of wall portions;
• a conveying member rotatably supported on the wall portions and configured to convey developer from one wall portion to the other;
• a developing roller rotatably supported in the housing and configured to carry the developer;
• and
• an image bearing member configured such that an electrostatic latent image is to be formed on a circumferential surface thereof, and arranged to face the developing roller;
• wherein the conveying member includes:
• a spiral member having opposite first and second end parts and being formed by connecting spiral pieces, each of the spiral pieces forming one spiral turn, in a conveying direction of the developer and including a hollow interior formed by the connected spiral pieces;
• an inner wall portion including a plurality of planar portions which define the hollow interior of the spiral member and are connected at predetermined angles in a circumferential direction of the rotation of the conveying member in a cross-section intersecting an axial direction of the conveying member, the planar portions constituting inner surfaces of the spiral pieces;
• first and second shaft portions arranged respectively at the opposite first and second end parts of the spiral member, rotatably supported on the wall portions and serving as a rotary shaft for the rotation of the conveying member
• the hollow interior is formed between the first and second shaft portions;
• and
• the conveying member has no other shaft part in the hollow interior.