Patent ID: 6871033

Claim:
A development unit developing an electrostatic latent image using developing agent into a visible image comprising: a holding chamber wall defining a holding chamber for holding therein the developing agent; a development chamber wall defining a development chamber; a partition wall interposed between the holding chamber and the development chamber, the partition wall being formed with a through hole for bringing the holding chamber into fluid communication with the development chamber; a conveyor disposed in the holding chamber for conveying the development agent from the development chamber to the holding chamber through the through hole; and a restrictor provided to partly block the through hole, the restrictor allowing the development agent conveyed by the conveyor to pass through the through hole from the holding chamber to the development chamber and restricting passage of developing agent through the through hole from the development chamber to the holding chamber; a developing agent bearing member provided in the development chamber, the developing agent bearing member developing agent for developing images; and a supply member located in the development chamber for supplying the developing agent to the developing agent bearing member, wherein the development chamber wall includes an inner ceiling located above the supply member, the supply member being vertically spaced away from the inner ceiling by 33 mm or more; and wherein the developing agent bearing member, the supply member, and the conveyor are arrayed in a substantially horizontal direction.