| 摘要 |
PROBLEM TO BE SOLVED: To improve the contact characteristic of dielectric parts, toners and a toner supplying member and to decrease a toner which is insufficient in electrostatic charge by forming the dielectric part in a projecting shape on the outer side in the circumferential direction. SOLUTION: This developing roller is constituted by forming many projecting dielectric parts 11 consisting of a fluororesin on the outer periphery of an aluminum roller 10 having a diameter of, for example, 25mm. The dielectric parts 11 are formed by embedding their base parts by, for example, 100μm, into the aluminum roller 10 and projecting their peak parts by, for example, 100μm, from the outer peripheral surface of the aluminum roller 10. The arrangement form is, for example, 300μm in pitch and 130μm in intervals. In such a case, the dielectric parts 11 are formed in the shape projecting toward the outer side in the circumferential direction of the roller and, therefore, the contact characteristic between the dielectric parts 11, the toner and the toner supplying roller is improved and the toner which is insufficient in electrostatic charge is decreased. Since the surface area of the dielectric parts 11 increases, the toner adhesion increases and eventually, the degree of reverse bias surface staining is improved. The degradation in density during the course of outputting is lessened even if an image having a high image area ratio is outputted. |
