Image forming apparatus

摘要

An image forming apparatus, includes a developing device developing an electrostatic latent image formed on an image bearing member. The developing device includes a developer bearing member having a developing sleeve and a magnet, with the developing sleeve being rotatable in the direction opposite to the rotational direction of the image bearing member, the magnet being fixed in the developing sleeve, and grooves extending in the axial direction being provided on a surface of the developing sleeve. An angle α between a wall surface of the grooves at an upstream side in the rotational direction of the developing sleeve and the direction perpendicular to the surface of the developing sleeve is greater than an angle γ of a magnetic brush of the developer formed at a closest portion between the image bearing member and the developer bearing member on an outermost surface of the developing sleeve.

主权项

1. An image forming apparatus, comprising:
an image bearing member; and a developing device which develops an electrostatic latent image formed on the image bearing member into a toner image using toner, the developing device accommodating two-component developer in which toner and carrier are mixed, the developing device including a developer bearing member which has a developing sleeve and a magnet, the developing sleeve being rotatable in the direction opposite to the rotational direction of the image bearing member at a portion opposing to the image bearing member, the magnet being fixed and held in the developing sleeve, a plurality of grooves extending in the axial direction being provided on a surface of the developing sleeve at a predetermined interval in the circumferential direction, wherein an angle α between a wall surface of each of the grooves at an upstream side in the rotational direction of the developing sleeve and the direction perpendicular to the surface of the developing sleeve is greater than an angle γ of a magnetic brush of the two-component developer formed at a closest portion between the image bearing member and the developer bearing member on an outermost surface of the developing sleeve.