| 摘要 |
PURPOSE:To reduce rotational torque and to prevent filming from occurring by constituting a developer carrier so that a dielectric part and a conductive part may coexist on the surface of the developer carrier in a state where they have very small areas and setting the surface roughness thereof at <=20mum by Rz reference. CONSTITUTION:The developer carrier 20 is constituted so that the dielectric part and the conductive part may coexist on the surface in the state where they have very small areas, and the surface roughness thereof is <=20mum by the Rz reference. Provided that the Rz means ten-point average roughness specified in JIS B 0601 and it expresses the value of a difference between the average of the heights from the highest peak to the fifth highest peak and the average of the heights from the deepest trough to the fifth deepest trough which are measured from a line which is parallel with an average line and does not intersect a cross sectional curve in the direction of axial magnification at a part obtained by extracting a reference length from the cross sectional curve by micrometer(mum). Thus, the rotational torque is reduced, the device is miniaturized and a jitter phenomenon is eliminated, then the filming of toner is restrained. |
