Developer Supply Device

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 a 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 rotated 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 that is located to face the developer holding body at a downstream end portion thereof in a developer transport direction and is configured to carry the developer through a traveling electric field to the developer holding body;
• a sub carrying substrate that has 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 so as to pass the developer to the main carrying substrate in the facing part,
• wherein the sub carrying substrate carries the developer in the facing part in a direction opposite to a direction in which the main carrying substrate carries the developer.