Patent ID: 8457535

Claim:
A development agent supply device for supplying charged development agent to an intended device, the development agent supply device comprising: a development agent holding member that comprises a development agent holding surface formed to be a cylindrical circumferential surface parallel to a main scanning direction, the development agent holding member being configured to rotate around an axis parallel to the main scanning direction such that the development agent holding surface moves in a moving direction perpendicular to the main scanning direction and faces the intended device in a development agent supply position; a casing formed to, when viewed in the main scanning direction, be elongated in a longitudinal direction that is substantially perpendicular to the main scanning direction and parallel to a horizontal direction, wherein the casing comprises: an opening formed at a first end in the longitudinal direction of the casing; and a development agent storage section that is formed at a second end in the longitudinal direction in a bottom region of an internal space of the casing and configured to store development agent, wherein the casing accommodates the development agent holding member such that the development agent holding surface faces the intended device via the opening; a first electric-field transfer board comprising a development agent transfer surface facing down, the first electric-field transfer board being configured to transfer development agent with a traveling-wave electric field, along the development agent transfer surface in a development agent transfer direction that extends from the development agent storage section to the opening, while making inadequately-charged development agent fall from the development agent transfer surface; and a second electric-field transfer board comprising: an upstream section disposed at an upstream side of the second electric-field transfer board in the development agent transfer direction, the upstream section being configured to face a downstream end of the first electric-field transfer board in the development agent transfer direction; and a downstream section disposed at a downstream side of the second electric-field transfer board in the development agent transfer direction, the downstream section being configured to face the development agent holding member, wherein the second electric-field transfer board is configured to transfer development agent received from the first electric transfer board at the upstream section, to the downstream section with a traveling-wave electric field.