| CPC G03G 15/0865 (2013.01) [G03G 9/08711 (2013.01); G03G 9/08755 (2013.01); G03G 15/081 (2013.01); G03G 15/0812 (2013.01); G03G 15/0889 (2013.01); G03G 15/09 (2013.01); G03G 15/50 (2013.01); G03G 21/0011 (2013.01)] | 5 Claims |
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1. A developing device for developing an electrostatic latent image formed on an image carrier, comprising:
a case for storing magnetic one-component developer containing only magnetic toner;
a developer carrier supported in a rotatable manner by the case, so as to carry the developer on its outer circumference surface;
a regulating blade that is disposed with a predetermined space to the developer carrier, and is made of magnetic material that forms a regulating part for regulating a layer thickness of the developer carried on the developer carrier;
a magnet member that is fixed in a non-rotatable manner inside the developer carrier, and has a plurality of magnetic poles disposed along a circumferential direction of the developer carrier; and
a blade magnet fixed to the regulating blade so as to induce a magnetic pole at the tip of the regulating blade, wherein
the toner contains toner mother particles containing binder resin and magnetic powder, and silica particles and alumina particles adhered to surfaces of the toner mother particles,
the alumina particles have a conductive-treated surface and have a primary particle size of 150 nm or more and 400 nm or less and resistivity of 0.1 Ωm or more and 2 Ωm or less, and
the developing device is capable of performing a developer removal mode, in which the developer carrier is rotated in a reverse direction opposite to a forward direction that is a rotation direction at image forming time, in a range of 1/18 or more and ⅕ or less of an outer circumference length of the developer carrier, so as to remove the developer staying at the regulating part.
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