Electrostatic printing device and electrode unit used in the electrostatic printing device

In electrostatic printing device comprising a column-shaped or cylinder-shaped particle carrier carrying toner particles on the surface thereof,

• a back electrode disposed opposite the particle carrier, and
• an electrode unit arranged between the particle carrier and the back electrode and formed with a plurality of apertures which are at least partially surrounded by control electrodes, and
• wherein electric voltage producing an electric potential difference between the particle carrier and the back electrode and applied electric voltage to the control electrodes of the electrode unit for controlling conveyance of toner particles toward the back electrode from the particle carrier to form a desired image on a recording medium disposed between the particle carrier and the back electrode, characterized in that;
• the electrode unit including:
• a base material of a resin film or resin sheet, the apertures being arranged in a predetermined direction of the substrate to provide rows of apertures, the rows of apertures on the electrode unit being arranged in the direction parallel to an axis of the particle carrier, and
• the electrode unit being arranged to be curved in the direction perpendicular to a longitudinal direction of the rows of apertures, and
• wherein when the substrate is bent in the direction perpendicular to the rows of apertures, the substrate curves in the longitudinal direction of the rows of apertures to create an image forming area defined by that portion on the substrate, in which displacements produced in directions away from the surface of the particle carrier are in a predetermined range of allowable error, and
• image unforming areas being not used for formation of an image and defined by those portions, which extend from both ends of the image forming area to both ends of the substrate.