To reduce contamination of a paper carrying roll caused by attachment of unfixed toner to the surface of the paper carrying roll the the prolong the service life by providing the surface layer thereof with ruggedness by the ruggedness of the outside circumferential surface of a substrate, and making an air layer intervene between the toner and the surface layer.
The average surface roughness of a core bar (metallic roll) 12 being the substrate of the surface layer 14 of the paper carrying roll (bias roll) is set to be the ruggedness of 0.5 to 10.0 μm. Then, the average width of the ruggedness is set to be smaller than the average grain size of the toner which is used, preferably, set to be ≤10.0 μm. By forming the layer 14 on the roll 12, the surface of the bias roll is properly roughened and air is made to intervene between the toner and the layer 14. Then, the bias roll is rotated in accordance with the movement of a paper 5 so as to carry the paper. When the contamination of the surface of the bias roll and a toner image 6 on the paper are evaluated by excepting a cleaning member 16, it is confirmed that the contamination of the surface of the roll is reduced in comparison with a conventional bias roll whose surface is smooth.
OTOME YUKIO
ROKUTANDA TAKASHI
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