| 摘要 |
A sleeve constituting a developing roller of a developing device has a cylindrical body with three layers composed of a base layer having rigidity and formed in a mesh-like shape, a filter layer for blocking toner passage, and a conductive layer to which a developing bias voltage is applied, which are arranged in this order from the inside. When a sucking device sucks from an open end of one end portion of the sleeve, an air flow going from the inside of the developing roller through the open end to outside is generated so that a pressure of the internal space of the developing roller becomes smaller compared with the outside. As the peripheral wall has air permeability in its thickness direction, air flows from the outer circumferential portion of the developing roller through the peripheral wall to the inside of the developing roller. |
