| 摘要 |
PURPOSE: To prevent the clogging of an opening for printing by providing a charged toner supply source adjacently on one side of a printing head structure and an image receiving member adjacently on the other. CONSTITUTION: In order to periodically clean a printing head 14, when the sheet 30 of paper is not present between the head 14 and a shoe 16, a switch 50 is operated, an AC power source 52 with DC bias is connected to the shoe 16 and control electrodes 34 and 40 are grounded. For a voltage from the power source 52, a frequency is the same as the voltage of the power source 28 used so as to scatter toner from a tanner supplier but a phase is shifted for 180 degrees. Thus, the toner present in the clearance of the head 14 and the sheet 30 of the paper is vibrated and the head 14 is bombarded. By the transition of movement between the vibrated toner and the toner accumulated on the head 14 and (or) Coulomb force supplied by an AC filed, the toner on the control electrode 40 is expelled and then accumulated on a supporting body passed on a shoe 16 or removed by a vacuum device. In such a manner, the clogging of the opening 36 for printing is prevented. |
