DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

摘要

The present invention suppresses out of balance of developer circulation in a developing device in which a developer carrying member and a stirring member are separately driven. Further, there is provided a developing device preventing an evil effect of an image such as improper coating when a surface of the developer carrying member is coated with a developer.;In a period from output of either earlier one of stop signals of motors 7, 8 to rotational stops of both of a developing sleeve 28 and a stirring screw 25 becoming not less than ½ of rotational stops in a steady state during image formation, a ratio α(E) between the rotational speed of the developing sleeve 28 and the rotational speed of the stirring screw 25 satisfies: 0.7<α(E)/α<2.0 relative to a ratio α between the rotational speed of the developing sleeve 28 in the steady state during image formation and the rotational speed of the stirring screw 25 in the steady state during image formation.

主权项

1. A developing device comprising:
a developing container configured to accommodate a developer including toner and magnetic particles; a developer carrying member rotatably provided opposed to an opening of said developing container; a stirring member configured to stir the developer in said developing container to supply the developer to said developer carrying member; a first driving device configured to drive said developer carrying member; a second driving member configured to drive said stirring member; and a controller configured to control drive of said first driving device and said second driving device, wherein said controller effects control so that in a period from output of either earlier one of a stop signal of said first driving device and a stop signal of said second driving device to rotational speeds of both of said developer carrying member and said stirring member becoming not more than ½ of rotational speeds in a steady state during image formation, the following formula is satisfied:
0.7<α(E)/α<2.0, where said α(E) is ωa(E)/ωs(E) wherein ωs(E) is a rotational speed of said developer carrying member and ωa(E) is a rotational speed of said stirring member, where said α is ωa/ωs wherein ωs is a rotational speed of said developer carrying member in the steady state during the image formation and ωa is a rotational speed of said stirring member in the steady state during the image formation.