A network based trading system and method are provided which combine economies-of-scale enjoyed by institutional investors and mutual funds with direct ownership of securities to permit individual investors to participate in the bond market in a cost effective manner. In one embodiment, characteristics describing a user’s web browsing history may be used to identify objects that are of interest to the user. The reference signal cycles are counted, creating a first binary count. A pressing mechanism is provided on the main frame and presses a bottom surface of the developing unit in a pressing direction along a straight line orthogonal to a rotational center shaft of the electrostatic latent image carrier and a rotational center shaft of the developer carrier.