Patent ID: 9304446
Filing Date: 2016-04-05
CPC Classification: G03G

Claim Text:
1. A developing device comprising: a developer carrying member for carrying a developer comprising a toner and a carrier; a magnet provided inside said developer carrying member; a developing chamber for feeding the developer to said developer carrying member; a feeding member rotatable provided in the developing chamber for feeding the developer in said developing chamber; a non-magnetic blade member for regulating an amount of the developer to be coated on said developer carrying member; and a route forming portion for forming a route for feeding the developer in the developing chamber from above to said developer carrying member with respect to a direction of gravitation, wherein said routing forming portion is located between said feeding member and said developer carrying member and includes an opposing portion opposed to said developer carrying member along a peripheral surface of said developer carrying member, wherein the magnet is opposed to a first region of said developer carrying member from a downstream end of said opposing portion with respect to the rotational direction of said developer carrying member to said blade member in the rotational direction of said developer carrying member so as to attract the developer on the first region, and wherein a distance of the first region in the rotational direction of said developer carrying member is 2 mm or more, and when a magnetic force at a surface of said developer carrying member with respect to a direction normal to said developer carrying member is Fr, magnetic poles are provided so that a ratio of an integrated value FrNear to an integrated value FrAll is 60% or more, wherein the integrated value FrNear is obtained by integrating the magnetic force Fr in a second region of the developer carrying member from a position of 2 mm upstream of said blade member with respect to the rotational direction of said developer carrying member to said blade member with respect to the rotational direction of said developer carrying member and the integrated value FrAll is obtained by integrating the magnetic force in the first region.