Patent ID: 7693465
Filing Date: 2010-04-06
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a photosensitive drum, having a CTL layer, on which a desired electrostatic latent image is formed; and a developing unit which accommodates a two-component developer comprising a toner and a carrier, provided with a developing sleeve which holds said two-component developer in a position opposing said photosensitive drum; wherein the external diameter of said photosensitive drum is 20 through 70 mm, and the film thickness of said CTL layer is 20 through 40 μm; the external diameter of said developing sleeve is 10 through 30 mm; a DC developing bias only is applied to said developing sleeve; the drawn amount of the two-component developer which is drawn onto said developing sleeve and arrives at said opposing position is 40 through 70 mg/cm the magnetic flux density in the normal direction of a main pole formed at said opposing position, of a plurality of magnetic poles formed on said developing sleeve, is 80 through 140 mT, and the magnetic flux density in the normal direction of a magnetic pole P the gap between said photosensitive drum and said developing sleeve at said opposing position is 0.2 through 0.5 mm; the linear speed ratio of said developing sleeve with respect to said photosensitive drum at said opposing position is 1.2 through 2.5; the toner concentration of the two-component developer accommodated in said developing unit is controlled so as to be 4 through 14 wt %; the weight-average particle size of said toner is 3.5 through 7.5 μm; and said carrier has a weight-average particle size of 20 through 60 μm, a static resistance of 10