Printing apparatus and print medium conveyance control method

A printing apparatus which conveys a print medium up to a print start position from stacking means for stacking print media, and prints on the print medium by a printhead, comprising:

• a feed roller for picking up a print medium from the print media stacked in the stacking means and conveys the print medium;
• an encoder, provided on said feed roller, for detecting a conveyance speed of the print medium;
• a conveyance roller, interposed between said feed roller and the print start position on a conveyance path of the print medium, for conveying the print medium up to the print start position;
• a sensor, interposed between said feed roller and said conveyance roller on the conveyance path of the print medium, for detecting a leading end of the print medium conveyed by said feed roller;
• generation means for generating a pulse signal;
• a feed motor for driving said feed roller by receiving the pulse signal generated by said generation means;
• control means for controlling said generation means to generate the pulse signal so as to make the conveyance speed of the print medium detected by said encoder come close to a target speed;
• calculation means for calculating, every predetermined timing, a duty of the pulse signal generated by said generation means;
• storage means for storing a duty of the pulse signal input to said feed motor when said sensor detects the leading end of the print medium;
• determination means for determining whether or not a difference between the duty calculated by said calculation means and the duty stored in said storage means has exceeded a predetermined value;
• stop means for stopping supply of the pulse signal input to said feed motor when said determination means determines that the difference has exceeded the predetermined value;
• and
• driving means for driving said conveyance roller when said stop means stops supply of the pulse signal input to said feed motor.