Patent ID: 8489003

Claim:
A developing device comprising: a developer bearing body that rotates in a first direction; a supply brush roller that is disposed below the developer bearing body in opposition to and out of contact with the developer bearing body and rotates in the first direction, the supply brush roller having bristles that supply a developer to the developer bearing body; a brush contact member that has a first contact portion in contact with the bristles, the first contact portion lying above a first horizontal plane passing through a rotational axis of the supply brush roller, and upstream in the rotational direction of the supply brush roller of a portion thereof opposing the developer bearing body; and a thickness adjusting member that has a second contact portion, wherein the thickness adjusting member is in contact with the developer bearing body only at said second contact portion, and adjusts a thickness of a layer of the developer on the developer bearing body to a predetermined thickness, the second contact portion lying below a second horizontal plane passing through a rotational axis of the developer bearing body, and downstream in the rotational direction of the developer bearing body of the portion of the supply brush roller opposing the developer bearing body, wherein a first vertical plane passing through the first contact portion passes through the developer bearing body upstream in the rotational direction of the developer bearing body of all contact between the second contact portion and the developer bearing body, a second vertical plane passing through a most upstream end on the thickness adjusting member of contact between the thickness adjusting member and the developer bearing body, as measured in the rotational direction of the developer bearing body, is farther from the rotational axis of the supply brush roller than is the first vertical plane, and the brush contact member is plate-like and has an opening at an intersection with the second vertical plane.