Patent ID: 8660466
Filing Date: 2014-02-25
Classification: G03G

Abstract:
1. A development device that is mounted on an electrophotographic image forming apparatus including a photoconductive drum of which an electrostatic latent image is formed on a surface, the development device comprising: a developer tank in which a developer containing a toner and a carrier are stored; a toner replenishment port through which the toner is replenished into the developer tank; a development roller that rotates to supply the toner to the surface of the photoconductive drum on which the electrostatic latent image is formed while bearing the developer of the developer tank; a developer conveyance path that includes first and second developer conveyance paths and first and second communication paths, the first developer conveyance path being disposed on a side of the toner replenishment port, the second developer conveyance path being disposed on a side of the development roller, first and second developer conveyance paths being partitioned by a partition plate parallel to a shaft direction of the development roller, the first and second communication paths communicating the first and second developer conveyance paths on both sides in the shaft center direction; first and second developer conveying members that are disposed in the first and second developer conveyance paths; and a developer raking member that is rotatably disposed in at least one of the first and second communication paths, wherein the first and second developer conveying members comprise: the spiral blades of the first and second developer conveying members rotate to mutually convey the developer in opposite directions, the developer is agitated about a shaft center on the conveyance direction downstream side by the circumferential rotation blades of the first and second developer conveying members, and the developer raking member rotates to convey the developer in one of the developer conveyance paths to the other of the developer conveyance path while being not in contact with the circumferential rotation blade, thereby cycling the developer between the first developer conveyance path and the second developer conveyance path; wherein the developer raking member includes a short shaft that is rotatably provided in parallel with the rotating shaft and a raking blade having plural projection pieces that are radially provided on an identical circumference of the short shaft at equal center angles; wherein the circumferential rotation blade includes an agitating blade having plural projection pieces that are radially provided on an identical circumference of the rotating shaft at equal center angles; and wherein plural sets of the raking blade are disposed at predetermined intervals along the short shaft, plural sets of the agitating blade are disposed at predetermined intervals along the rotating shaft, and the plural sets of the raking blade and the plural sets of the agitating blade are located so as to be alternately arrayed in a shaft direction.