Patent ID: 8326190

Claim:
A developer supply device, comprising: a casing having an opening formed to face a supply target and a developer reservoir portion, provided on an opposite side with respect to the opening, to accommodate developer; a developer holding body that is a roller-like member having a cylindrical circumferential surface and a rotation axis extending in a main scanning direction so that the developer holding body is rotatable about the rotation axis, the developer holding body being placed around the opening to be accommodated in the casing and to face the supply target; a main carrying substrate positioned to face the developer holding body at a downstream end portion of the main carrying substrate in a developer transport direction and configured to carry the developer through a traveling electric field to the developer holding body; and a sub carrying substrate having a facing part where the sub carrying substrate faces the main carrying substrate, the sub carrying substrate being configured to carry the developer from the developer reservoir portion to the facing part through a traveling electric field generated, at least in part, by a portion of the sub carrying substrate, wherein the sub carrying substrate is further configured to pass the developer to the main carrying substrate through a space between the facing part of the sub carrying substrate and an upstream end portion of the main carrying substrate in the developer transport direction, wherein the sub carrying substrate carries the developer at the facing part in a direction opposite to a direction in which the main carrying substrate carries the developer, and wherein the sub carrying substrate is physically separate from the main carrying substrate.