Patent ID: 6136487
Filing Date: 2000-10-24
Classification: G03G

Abstract:
A reversal developing method of exposing the surface of a charged image carrying member to light to form an electrostatic latent image on the surface of the image carrying member, while conveying a developer containing toners and carriers to a developing region opposite to the image carrying member having the electrostatic latent image formed thereon in a state of a magnetic brush by a developer conveying member in such a way that the toners adhere to the light exposed area of the charged image carrying member, said method comprising the steps of:applying an oscillating developing bias voltage between the image carrying member and the developer conveying member,supplying the toners in the developer from the developer conveying member to the image carrying member in the developing region, to carry out development of the electrostatic latent image, andcarrying out the development in such a manner that the relationship among an amount per unit area M (mg/cm.sup.2) of the developer conveyed to the developing region by said developer conveying member, the bulk density P of said developer, and a distance Ds (mm) between the developer conveying member and the image carrying member which are opposite to each other in the developing region satisfies the following conditions:0.10.ltoreq.M/(P.multidot.Ds).ltoreq.0.30 and300 V.ltoreq..DELTA.V.ltoreq.600 Vwherein .DELTA.V is .vertline.Vir-Vc.vertline. and Vc is a value between V0 and Vir, said Vc being a center voltage a value of which is obtained by dividing a time integral value of a voltage wave form of said oscillating developing bias voltage by a period of said oscillating developing bias voltage, said Vir being a surface potential at an exposed portion of the image carrying member, and said V0 being an initial surface potential at the charged image carrying member.