Mitsubishi Heavy Industries Limited

Yoshio Ueda

Norifumi Tasaka

Hitoshi Hirose

Masakazu Akatsuka

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.

Apparatus and method for controlling drag roller

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. Also, a plurality of tension sensors for detecting a tension of a web between a feeder and a feed drag roller and between drag rollers disposed in a region from the paper feed side to the paper discharge side of a printing machine are provided, and a controller to which a tension detection signal from the plurality of tension sensors is supplied as a control signal is provided, by which slack of the web is removed and a predetermined preliminary tension is given to the web successively from the upstream side of a web running path by driving each drag roller with torque control based on the control signal from the controller at the start time of printing, and thereafter the driving of the drag roller at a location where the slack of the web has been removed is switched to speed control successively.

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Hiroshima-ken, Japan

Yoshio Ueda