Roll paper conveying apparatus, inkjet printer, and roll paper conveying method

A roll paper conveying method comprising:

• intermittently conveying roll paper by an amount of paper to be fed corresponding to a predetermined print width to a predetermined printing position with a carriage roller that is driven by a conveying motor;
• unwinding the roll paper, and pulling and conveying the roll paper toward the carriage roller intermittently with a paper feeding roller that is driven by a feed motor;
• detecting a rotation angle of the paper feeding roller with a first detecting unit;
• performing feedback control of the feed motor using a detection value of the first detecting unit so that a conveying speed and a conveying position of the roll paper follow target values of a feed motor control unit;
• keeping a movable member in contact with the roll paper at a position between the paper feeding roller and the carriage roller, and displacing the movable member from a reference position to absorb a change in a tensile force of the roll paper caused by a difference between rotation speeds of the paper feeding roller and the carriage roller;
• detecting a position of the movable member with a second detecting unit;
• and
• calculating, with a correcting unit, a correction value corresponding to an amount of displacement of the movable member from the reference position and an integration of the amount of displacement based on a detection value of the second detecting unit and correcting an output of the feed motor control unit using the correction value thus calculated.