Image forming and fixing apparatuses having fixing and pressing rotating member and rectification element

摘要

By connecting a first diode between a conductive heating element of a fixing roller and ground, electric charge with the same polarity as the charged polarity of toner can be held on the surface of the fixing roller. Meanwhile, by connecting a second diode between the surface of a pressing roller that does not contact an un-fixed toner image and ground, electric charge with the reverse polarity of the charged polarity of the toner can be held at the surface of the pressing roller. The polarity of the electric charge induced by electromagnetic induction is held at the polarity determined by the two diodes, and as a result the fixing offset can be suppressed without adding a collector member or a charging capacitor.

主权项

1. A fixing apparatus comprising:
a fixing rotating member, which includes an electrically conductive heating layer and a magnetic field generation unit that generates an eddy current in the electrically conductive heating layer by generating a magnetic field, and generates heat by the eddy current flowing in the electrically conductive heating layer; an electric power supply unit that causes the magnetic field generation unit of the fixing rotating member to generate the magnetic field by supplying electric power to the magnetic field generation unit; a pressing rotating member, which is arranged opposite to the fixing rotating member, and, together with the fixing rotating member, forms a pressing part that presses an un-fixed toner image to a sheet; a first rectification element, which is connected between the electrically conductive heating layer of the fixing rotating member and ground, and causes the surface of the fixing rotating member that contacts the un-fixed toner image to hold electric charge with the same polarity as the charged polarity of the un-fixed toner image, the first rectification element being configured to connect to the electrically conductive heating layer of the fixing rotating member via a first electrically conductive brush; a second rectification element, which is connected between the surface of the pressing rotating member that does not contact the un-fixed toner image and ground, and causes the surface of the pressing-rotating member to hold electric charge with the reverse polarity of the charged polarity of the un-fixed toner image, the second rectification element being configured to connect the surface of the pressing rotating member via a second electrically conductive brush; and a first electric potential adjusting element, which includes a transistor and is connected between the first rectification element and ground, configured to vary and adjust the electric potential induced at the electrically conductive heating layer due to behavior of the magnetic field generation unit.