An apparatus includes an upstream transport surface TSa which, while
facing a circumferential surface DS of a developing roller 33, is
disposed upstream of an area (developing area) in the vicinity of a
latent image forming surface LS, and a downstream transport surface TSb
which, while facing the circumferential surface, is disposed downstream
of the developing area. The apparatus forms electric fields on the
upstream and downstream transport surfaces for moving a charged developer
T from an upstream side toward a downstream side. In the apparatus, the
transport speed of developer on the upstream transport surface is higher
than that on the downstream transport surface. As a result, there can be
lowered a speed at which the developer which has not adhered to the
circumferential surface and has reached a downstream end portion of the
upstream transport surface flies out toward the vicinity of the
developing area. Also, there can be avoided a problem in that the
developer stagnates at an upstream end portion of the downstream
transport surface with a resultant hindrance to collection of the
developer.