Widthwise paper drift correction device for elongated web-like print paper

A printing device for printing on an elongated web-like print paper having a width and side edges substantially perpendicular to a widthwise direction of the print paper the printing device comprising;

• a paper conveying mechanism for conveying the print paper along a predetermined path, the print paper being conveyed so that side edges are in coincidence with a paper conveying direction;
• a first sensor disposed at a first position in the predetermined path, for sensing a position of a side edge of the print paper and outputting a first signal;
• a second sensor disposed at a second position in the predetermined path, the second position being apart a predetermined distance from the first position and downstream of the first position with respect to the paper conveying direction, the second sensor sensing a position of the side edge of the print paper and outputting a second signal;
• delaying means for delaying outputting the first signal by a predetermined period of time corresponding to a paper conveying time for conveying the print paper from the first position to the second position;
• computing means for computing a difference between the first signal output from the delaying means and the second signal and outputting a difference signal;
• a widthwise moving mechanism for moving the print paper in the widthwise direction;
• and
• a controller for generating a drive signal based on the difference signal and outputting the drive signal to the widthwise moving mechanism so that the widthwise moving mechanism is driven in response to the drive signal and corrects the position of the print paper in the widthwise direction.