PURPOSE: To make formation of minute and clear images possible by a method wherein a rear side electrode, control grid and a toner transfer body are arranged from above at specified intervals so that the toner transfer body comes to the lowermost position.

CONSTITUTION: An image formation unit is constructed by providing from above a rear side electrode plate and a control grid 12 with a recording paper transfer passage placed in between, and a toner transfer belt 13 placed extending over a span between a pair of rollers 14 and 15 is provided furthermore to the underside of the control grid 12, and each of the above three members is placed approximately horizontal in parallel with one another at minute intervals. The transfer belt 13 is surrounded, except its surface side, with toner containers 16. The toner transfer belt 13 is extended over a span between a tension roller 14 which is energized by a spring 17 and is positioned on the downstream side of the transfer direction and a toner carrying roller 15 positioned on the upstream side. A developing electrode plate 18 is provided to a position or the back 13a side of the belt 13 facing the control grid 12, and an electromagnetic plate 20 that is operated by switching-on-and-off and is capable of making applied voltage variable is provided to the underside of the developing electrode plate.