Abstract: A developing device includes a developer carrier having a surface carrying a one-component developer thereon, developer control member abutting against the developer carrier to control a thickness of a layer of the developer, and a charge generation device provided downstream of the developer control member, as seen in a direction of a rotation of the developer carrier, and applying electric charge of a single polarity to a developer layer on the developer carrier, wherein the developer is charged under a condition that internal to the developer layer there occurs small aerial discharge caused by an electric field created by electric charge applied to a surface of the developer layer. Thus, the developing device can use a one-component developer, does not require toner having its components subtly adjusted and can cancel toner charged opposite in polarity, to form an image of high quality.

Abstract: This invention relates to a motor drive device for a stepping motor used for equipment such as facsimile machine, a scanner and a printer. The motor drive device changes an excitation phase of the stepping motor in response to a motor drive instruction signal sent from a control circuit of the equipment. The motor drive device includes a register for receiving and storing data about delay times and excitation ratios sent from the control circuit of the equipment. The motor drive device changes the excitation phase of the stepping motor in accordance with the data stored in the register. The motor drive device can shorten equipment design period and reduce manufacturing cost. Further, the motor drive device can improve image reading resolution and image recording qualities.

Abstract: An alternating current limiting apparatus is disclosed which normally forms first and second series circuits connected in parallel with each other between different kinds of power system lines. The first series circuit is resonated with a reactor and a capacitor at a line frequency to directly interconnect the power system lines. The second series circuit is composed of a capacitor or a reactor and two resistors. Between the interconnection of the reactor and the capacitor of the first series circuit and the interconnection of both resistors, a closing device is connected. Upon the occurrence of a fault of either of the power systems, the closing device is thereby actuated to form a parallel resonance circuit with the combination of the reactor or capacitor of the first series circuit and the capacitor or reactor of the second series circuit to limit current flowing between the power system lines.