Patent ID: 7809314
Filing Date: 2010-10-05
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: one or more image bearing members configured to form one or more toner images thereon at a predetermined process speed; a plurality of supporting rollers; a belt-shaped medium configured to be charged with a charge voltage, rotatable, extended between the plurality of supporting rollers, and held in contact with the one or more image bearing members; one or more primary transfer members corresponding to the one or more image bearing members on a one-to-one basis, and configured to sequentially transfer the one or more toner images formed on the one or more image bearing members onto the belt-shaped medium; a secondary transfer member configured to transfer the one or more toner images carried on the belt-shaped medium onto a recording sheet; at least one conductive roller connected to a ground and arranged upstream from the one or more primary transfer members and downstream from the secondary transfer member in a rotation direction of the belt-shaped medium, and in contact with the belt-shaped medium for a predetermined wrapping length, wherein a relationship Tb<X/Vb is satisfied, where Tb is an attenuation time period, expressed in units of seconds, that the charge voltage of the belt-shaped medium decays from approximately 200 volts to 200/e volts, where e is a base of a natural logarithm, X is the predetermined wrapping length, expressed in units of millimeters, of the belt-shaped medium against the at least one conductive roller, and Vb is the predetermined process speed, expressed in units of millimeters per second.