Patent ID: 7738803

Claim:
An image forming apparatus, comprising: an image carrier configured to carry an image on a surface thereof and rotate continuously; an image forming unit configured to form a latent image on the surface of the image carrier; a developing unit configured to develop the latent image formed on the surface of the image carrier into a visible toner image; a charging member including a charging brush roller configured to rotate continuously with the image carrier at a portion contacting the image carrier and uniformly charge the surface of the image carrier while contacting a surface thereof with the surface of the image carrier at a charge nip; a charge bias applying unit configured to apply a charge bias to the charging member; a controller configured to control driving of the image carrier and the charging member, wherein the controller reduces, at the charge nip at a given timing, a linear velocity ratio of a travel speed of the surface of the charging brush roller to a travel speed of the surface of the image carrier, and the surface of the charging brush roller and the surface of the image carrier move in a same direction at the charge nip; the controller is further configured to decrease over time the linear velocity ratio at the charge nip during reduction of the linear velocity ratio; and the charge bias applying unit is further configured to apply a direct current voltage having a polarity opposite to a regular polarity of toner to the charging member during reduction of the linear velocity ratio.