Abstract: The present invention relates to a printing method by an offset printing press and an offset printing press and has an object to carry out a substrate process for low-whiteness printing paper such as paper for newspaper with substrate treatment agent and to enhance the print quality while preventing appearance of muddiness in printing ink by the substrate treatment agent. The present invention is configured such that substrate treatment agent such as low-whiteness enhancement agent is supplied to a printing face of printing paper, and thereafter the substrate treatment agent supplied to the printing face is dried and then offset printing is carried out for the printing paper by a printing apparatus.

Abstract: An apparatus for and a method of controlling a drag roller in a printing machine to move a web with no shift of a printing position and enhance the printing quality remarkably, even when the drag roller varies in diameter due to its temperature change. From a given temperature-rotational-speed table, a controlling unit obtains a rotational speed of the drag roller so as to adjust a circumferential speed of the drag roller, which speed corresponds to the current circumferential surface temperature checked by a temperature monitor unit. Then, a rotational speed changing unit changes the rotational speed of the drag roller to a value equivalent to the rotational speed obtained by the controlling unit.

Abstract: An apparatus for and a method of controlling a drag roller in a printing machine to move a web with no shift of a printing position and enhance the printing quality remarkably, even when the drag roller varies in diameter due to its temperature change. From a given temperature-rotational-speed table, a controlling unit obtains a rotational speed of the drag roller so as to adjust a circumferential speed of the drag roller, which speed corresponds to the current circumferential surface temperature checked by a temperature monitoring unit. Then, a rotational speed changing unit changes the rotational speed of the drag roller to a value equivalent to the rotational speed obtained by the controlling unit.

Abstract: Drag rollers disposed in a region from the paper feed side to the paper discharge side of a printing machine are driven one after another from the paper feed side with torque control, by which the slack of a web is removed successively from the upstream side of a web delivery running path.