| CPC G03G 15/0808 (2013.01) [G03G 15/0868 (2013.01); G03G 15/0889 (2013.01); G03G 21/0047 (2013.01)] | 7 Claims |
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1. A developing device comprising:
a developing container configured to accommodate a developer containing toner and a carrier;
a developing roller configured to carry and convey the toner to a developing position where an electrostatic latent image formed on an image bearing member is developed with the toner;
a supplying roller provided opposed to the developing roller and configured to supply only the toner to the developing roller while carrying and conveying the developer supplied from the developing container, the supplying roller being rotated during image formation in a rotational direction opposite to a rotational direction of the developing roller in a position where the supplying roller and the developing roller oppose each other;
a first magnet provided non-rotationally and fixedly inside the developing roller and including a first magnetic pole;
a second magnet provided non-rotationally and fixedly inside the supplying roller and including:
a second magnetic pole which is provided opposed to the first magnetic pole in a position where the supplying roller opposes the developing roller and which is different in polarity from the first magnetic pole, and
a third magnetic pole which is provided on a side upstream of the second magnetic pole with respect to the rotational direction of the supplying roller during the image formation, and
a regulating member provided opposed to the third magnetic pole and configured to regulate an amount of the developer carried on the supplying roller,
wherein during non-image formation, an operation in a mode in which the supplying roller is rotated in a direction opposite to the rotational direction of the supplying roller during the image formation is executable, and
wherein with respect to the rotational direction of the supplying roller during the image formation, a position where a magnet flux density of the third magnetic pole in a tangential direction to an outer peripheral surface of the supplying roller is zero is positioned downstream of an upstream end of the regulating member and upstream of the second magnetic pole.
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