Patent ID: 6198895
Filing Date: 2001-03-06
Classification: G03G

Abstract:
A developing device comprising:a developer carrier including a magnetic field generating device therein, configured to carry and convey a developer containing toner and magnetic carrier particles;a first regulating member configured to regulate the developer being carried and conveyed by the developer carrier;a developer storing section configured to store developer scraped off the developer carrier by the first regulating member, the developer storing section including a second regulating member for regulating the developer being carried and conveyed by the developer carrier arranged upstream of the first regulating member with respect to a direction in which the developer carrier conveys the developer; anda toner storing section provided adjacent to the developer storing section to supply toner to the developer carrier,wherein, a contact condition of the developer carried on the developer carrier with the toner supplied to the developer carrier from the toner storing section is varied in accordance with variation of a toner density in the developer carried on the developer carrier to thereby vary a condition of the developer on the developer carrier to attract the toner,the second regulating member is spaced from the developer carrier such that when a thickness of a layer of the developer on the developer carrier increases due to an increase of the toner density in the developer on the developer carrier, the second regulating member regulates an increased amount of the developer being carried and conveyed by the developer carrier, anda magnetic force exerted on the developer on the developer carrier satisfies a following condition:.mu.X Fr1+Ft1<.mu.X Fr2+Ft2 (1)where .mu. is a coefficient of friction between the developer and a surface of the developer carrier, Fr1 is a radial direction component of the magnetic force at a position of the developer carrier facing the first regulating member, Ft1 is a tangential direction component of the magnetic force at the position of the developer carrier facing the first regulating member, Fr2 is a radial direction component of the magnetic force at a position of the developer carrier facing the second regulating member, and Ft2 is a tangential direction component of the magnetic force at the position of the developer carrier facing the second regulating member, and where a direction in which the developer is attracted to the developer carrier is defined as a positive direction in the radial direction component of the magnetic force, and a developer conveying direction is defined as a positive direction in the tangential direction component of the magnetic force.