The invention pertains to a connector for at least one cable with one or more conductors, comprising at least one housing of an electrically insulating material containing contact elements that are connected or to be connected to the conductors. The method includes: during the testing, once a first byte in a first sector fails the testing, stopping testing the rest bytes in the first sector which haven’t been tested, and skipping the testing to a second byte in a second sector. In image forming process, toner particles uniformly dispersed in carrier are agglutinated to the elastic roller side by means of compaction.