Process cartridge and image forming apparatus having process cartridge that has a plurality of measuring electrode members

1. Field of the Invention A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus includes an electrophotographic photosensitive member, a process device acting on the member, a developer container for containing developer, and a plurality of measuring electrode members. The plurality of measuring electrode members are disposed at a location capable of contacting the developer and include input side and output side electrodes having at least one pair of portions juxtaposed with a predetermined interval therebetween. The interval between the juxtaposed portions of the input side and output side electrodes is different for every measuring electrode member. The cartridge also includes a plurality of measuring electrode output contacts electrically connected to the output side electrodes of the plurality of measuring electrode members, and a common input contact electrically connected to the input side electrodes of the plurality of measuring electrode members.