Abstract: In a method and apparatus for transferring data between a master unit MU, and slave units SU0, SU1 . . . SUX according to a synchronizing signal generated by the master unit MU, the master unit MU outputs information specifying a unit to be a data transferring source, and the unit corresponding to that information transmits data held by the unit itself and the other units so that, data transferring is performed between the units MU, SU0, SU1 . . . and SUX, and it becomes possible for all the units including the master unit to receive data from the data transmitting source.

Abstract: A two-component developer comprising a magnetic carrier having a carbon black-containing resin-coating layer and a toner composed of a carbon black-containing resin composition is disclosed. A styrene resin, an acrylic resin or a styrene-acrylic copolymer resin is selected as each of the carrier-coating resin and the toner-forming resin, and the carbon black content A in the carrier-coating layer and the carbon black content B in the toner-forming layer satisfy requirements represented by the following formulae: ##STR1## Namely, by adjusting the carbon black contents A and B within specific ranges relatively to each other, a two-component developer which is well-balanced between the frictional chargeability characteristic and the electric resistance is provided.