To form a sharp image on an image recording medium by a method wherein a pressing force is added on an aperture electrode body made of ceramic and the aperture electrode body is brought in close proximity to a charged particle supplying means as close as possible, then a strong electric field is generated in an aperture so that toner is made to smoothly pass the aperture and fly and to prevent the damage of the aperture electrode body by strengthening it by a holder.

An aperture electrode body 1 is attached to a holder having a rectangular hollow section so that the aperture electrode body 1 is strengthened. It is fixed to a toner case 11 which is a body frame with the holder 7 therebetween. The aperture electrode body 1 is pressed by a plate spring 1 5 as an elastic member toward a direction that a circumference face section disposed along the aperture array presses a toner carrier roller 14.