Image forming apparatus and method of controlling image forming apparatus

摘要

An image forming apparatus includes a developer supplying roller for supplying to a predetermined print position a developer charged to predetermined polarity, and a print head provided in the print position and having electrode pairs which are respectively provided with developer passing holes, each pair including a first electrode and a second electrode connecting with each other, and being so adapted that the developer passing holes are opened or closed by control of an electric field between the first and second electrodes, on the basis of whether print dot data is sent in synchronization with a predetermined print clock signal. At a time when the print dot data is sent in synchronism with the print clock signal, the electric field is controlled such that the developer is attracted from the developer supplying roller to the first electrode. On the other hand, at a time when the print dot data is not sent in synchronism with the print clock signal, the electric field is controlled such that the developer is attracted from the first electrode to the developer supplying roller. Further, in the image forming apparatus in accordance with the present invention, an ultrasonic vibration applying device is contemplated as applying ultrasonic vibration to the print head.