Paper, board and cardboard are produced by draining paper stock containing interfering substances in the presence of fixing agents by a process in which the fixing agents used are reaction products which are obtainable by reacting amino- andor ammonium-containing polymers selected from the group consisting of the. The modular components are preferably in turn adapted from standard industry components. The smaller piston unit is electrically driven, wherein the axial displacement of the smaller piston unit may be transmitted to the cylinder. 0\xd710\u22123 to 8\xd7102 \u03a9cm and a carrier concentration is controlled to fall within the range of 5. In a full-color mode, since each transfer bias is applied to all stations, the waste toner is collected into the station on the uppermost stream.