direction of the paper feed when the nozzle 61 is moved to a position in correspondence to a printing position a dc voltage is applied between the electrodes 63 64 by closing the switch 66 with a jet controller 75 according to an image signal sent for example from an image reader not shown at the same time a dc voltage is applied to a needle electrode in the needle electrode array 67 in correspondence to the printing position then toner particles having been beforehand charged are ejected from the orifice 62 so as to adhere on an appropriate position on the paper 69 though it is most economical to apply a dc voltage only on one electrode in correspondence to the printing position the voltage may also be applied uniformly to all needle electrodes of the array 67 as a mechanism such as carriages 22 77 for moving one or a few nozzles relative to the paper there may be used a head driving mechanism employed in a conventional inkjet printer or that of a thermal printer see for example a u s patent application ser no 786 821 filed on sept 27 1985 by the same assignee of the application the size of the nozzle head can be made smaller when compared with an inkjet printer of the pulsed pressure type because a large change in volume can be induced with a small action area the head has a long life because.