Patent ID: 7574165

Claim:
A fixing device comprising: a fixing member which is in contact with an unfixed image formed on a printing medium with a developer; and a pressure member which is in contact with the fixing member, the fixing member and the pressure member sandwiching the printing medium so as to feed the printing medium, so that the unfixed image on the printing medium is fixed on the printing medium, the fixing device further comprising holding electric field generating means for generating a holding electric field which is an electric field in a direction for holding a reverse polarity developer on the printing medium, the reverse polarity developer having a polarity opposite to a polarity of the developer which forms an image on the printing medium, wherein said holding electric field generating means includes bias voltage applying means for applying a bias voltage, which generates the holding electric field, to at least one of the fixing member and the pressure member, wherein: the pressure member includes a conductive core bar, an insulating elastic layer on the conductive core bar, an intermediate layer on the insulating elastic layer, and a surface resistive layer on the intermediate layer; a potential given member is provided on a surface of the pressure member; said bias voltage applying means applies the bias voltage to the potential given member; and the bias voltage is applied through the potential given member to a surface of the pressure member or near the surface of the pressure member, wherein: the fixing member includes first heating means for heating a surface of the fixing member; and the potential given member also functions as a heating member for heating the surface of the pressure member.