Conductive foam rubber roller used in image formation apparatus such as electrophotographic apparatus

An image formation apparatus comprising:

• an electrostatic latent image carrying body means for carrying an electrostatic latent image formed thereon;
• and
• a developing roller means for entraining the developer to bring an electrostatically-charged toner developer to said electrostatic latent image carrying body means for a development of the electrostatic latent image with the toner developer;
• a toner-removing roller means for removing a toner developer not used for the development of the electrostatic latent image from said developing roller;
• and
• a transfer roller means for electrostatically transferring a charged toner image developed by said developing roller means from said electrostatic latent image carrying body means to a recording medium such as a paper,
• wherein at least one of said developing roller means, said toner-removing roller means, and said transfer roller means includes a conductive foam rubber roller which comprises:
• a conductive tubular foam rubber roller element having a central bore defined by a solid skin layer having an electric resistivity considerably higher than that of a conductive foam structure of said conductive tubular foam rubber element;
• a conductive shaft member on which said conductive foam rubber roller element is mounted and fixed;
• and
• an electric contact establishing means provided between said conductive tubular foam rubber roller element and said conductive shaft member for establishing a sufficient electric contact therebetween.

An electrophotographic recording apparatus comprising:

• an electrostatic latent image carrying body means;
• a charging roller means for producing an electrically-charged zone on said electrostatic latent image carrying body means;
• an optical writing means for optically writing an electrostatic latent image on the electrically-charged zone of said electrostatic latent image carrying body means;
• a developing roller means for entraining the developer to bring an electrostatically-charged toner developer to said electrostatic latent image carrying body means for a development of the electrostatic latent image with the toner developer;
• a toner-removing roller means for removing a toner developer not used for the development of the electrostatic latent image from said developing roller;
• and
• a transfer roller means for electrostatically transferring a charged toner image developed by said developing roller means from said electrostatic latent image carrying body means to a recording medium such as a paper,
• wherein at least one of said charging roller means, said developing roller means, said toner-removing roller means, and said transfer roller means includes a conductive foam rubber roller which comprises:
• a conductive tubular foam rubber roller element having a central bore defined by a solid skin layer having an electric resistivity considerably higher than that of a conductive foam structure of said conductive tubular foam rubber element;
• a conductive shaft member on which said conductive foam rubber roller element is mounted and fixed;
• and
• an electric contact establishing means provided between said conductive tubular foam rubber roller element and said conductive shaft member for establishing a sufficient electric contact therebetween.