Method of producing an electrically conductive roller from a rubber foam tube

A production method for producing a rubber foam tube, the method comprising the steps of:

• extruding a rubber composition containing a foaming agent into a tubular body;
• continuously feeding the extruded tubular body in an elongated state without cutting to pass the tubular body through a microwave crosslinking device and then through a hot air crosslinking device to continuously foam and crosslink the rubber composition;
• wherein the tubular body passes through the microwave crosslinking device at a speed V1 which is not less than 6 m/min and not greater than 8 m/min;
• and
• wherein the tubular body passes through the hot air crosslinking device at a speed V2 such that a ratio V2/V1 is not less than 1.2 and not greater than 1.6.