Apparatus and method for controlling drag roller

A drag roller control apparatus for controlling a drag roller, by which a printing web is pulled, in a printing system, comprising:

• a diameter monitoring unit for checking a diameter of the drag roller;
• a controlling unit, operatively connected with said diameter monitoring unit, for issuing a control signal for controlling a rotational speed of the drag roller so as to adjust a circumferential speed of the drag roller, which speed corresponds to said diameter checked by said diameter monitoring unit, to a preset speed corresponding to a reference diameter of the drag roller;
• and
• a rotational speed changing unit, operatively connected with said controlling unit, for changing the rotational speed of the drag roller in accordance with said control signal issued from said controlling unit.

A drag roller control method of controlling a drag roller, by which a printing web is pulled, in a printing system, comprising the steps of:

• checking an temperature of the drag roller by a temperature monitoring unit;
• issuing a control signal for controlling a rotational speed of the drag roller so as to adjust a circumferential speed of the drag roller, which speed corresponds to said temperature checked in said temperature checking step, to a preset speed corresponding to a reference temperature of the drag roller by a controlling unit operatively connected with said temperature monitoring unit;
• and
• changing said rotational speed of the drag roller in accordance with said control signal issued in said control signal issuing step by a rotational speed changing unit operatively connected with said controlling unit.