DEVELOPMENT DEVICE AND IMAGE FORMING APPARATUS USING THE DEVICE

摘要

PROBLEM TO BE SOLVED: To easily well-balance between developer replenishing control and developer transport abnormality control for a two-component development system using toner and carrier.

SOLUTION: A development device includes: a density detector 8 that is disposed at a region facing a developer carrier 3 in a developer circulation path 5 and performs detection of toner density of a developer G; first control means 9 for controlling a developer replenishing mechanism 7 so as to replenish the developer G if density information put forth by the density detector 8 represents density at or less than a threshold on the basis of an output of the density detector 8 in the case of the output being within a predetermined range of limits; and second control means 10 for controlling a developer transport mechanism 4 so as to determine that abnormality in transport operation of the developer G by the developer transport mechanism 4 has occurred if a change rate of the output reaches or exceeds a predetermined threshold on the basis of an output of the density detector 8 in the case of the output being outside the predetermined range of limits.

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