| CPC G03G 15/0907 (2013.01) [G03G 15/0891 (2013.01); G03G 15/0935 (2013.01)] | 13 Claims |
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1. An image forming apparatus comprising:
an image bearing member;
a developing device including:
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 the 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 developing roller being rotated in a rotational direction opposite to a rotational direction of the supplying roller in a closest position where the supplying roller is positioned closest to the developing roller,
a first magnet provided non-rotationally and fixedly inside the developing roller and including a first magnetic pole, and
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 and which is different in polarity from the first magnetic pole;
a conductive roller arranged facing the supplying roller and the developing roller, downstream of the developing position and upstream of the closest position in the rotational direction of the developing roller, a shortest distance between the conductive roller and the developing roller being shorter than a shortest distance between the conductive roller and the supplying roller;
a driving source configured to drive each of the supplying roller, the developing roller, and the conductive roller; and
a bias applying portion configured to apply a bias to each of the supplying roller, the developing roller, and the conductive roller,
wherein during image formation, the bias is applied to each of the supplying roller, the developing roller, and the conductive roller in a state in which each of the supplying roller, the developing roller, and the conductive roller is rotationally driven, and
wherein during the image formation,
a polarity of a first potential obtained by subtracting a DC potential of the developing roller from a DC potential of the supplying roller is the same as a normal charge polarity of the toner, and
a polarity of a second potential obtained by subtracting the DC potential of the developing roller from a DC potential of the conductive roller is the same as the normal charge polarity of the toner.
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