Printing apparatus, feeding apparatus, and feeding control method

A feeding apparatus which conveys a stacked printing medium to a predetermined position, comprising:

• a first roller which conveys the printing medium from a stacking position of the printing medium into a printing apparatus which uses the printing medium;
• a DC motor which supplies a driving force to said first roller;
• an encoder which detects a rotation amount of said first roller;
• generation means for generating a target position to cause said first roller to feed the printing medium;
• correction means for correcting the target position generated by said generation means;
• control means for generating a PWM signal on the basis of (1) the target position generated by said generation means or corrected by said correction means and (2) a detected position derived from the rotation amount detected by said encoder, and servo-controlling said DC motor by the PWM signal;
• comparison means for repeatedly comparing the target position generated by said generation means or corrected by said correction means with the detected position derived from the rotation amount detected by said encoder in every servo period;
• and
• correction control means for controlling said correction means to perform correction in a case where a difference between the target position and the detected position, obtained by comparison result by said first comparison means, is larger than a predetermined threshold value.

A method of feeding a stacked printing medium via a roller to which a driving force is supplied from a servo-controlled DC motor, comprising the steps of:

• detecting a rotation amount of the roller by using an encoder;
• generating a target position to feed the printing medium by the roller;
• correcting the target position generated in the generating step;
• generating a PWM signal on the basis of (1) the target position generated in the generating step or corrected in the correcting step and (2) a detected position derived from the rotation amount detected by the encoder, and servo-controlling the DC motor by the PWM signal;
• repeatedly comparing the target position generated in the generating step or corrected in the correcting step with the detected position derived from the rotation amount detected by the encoder in every servo period;
• and
• controlling to perform correction in the correcting step in a case where a difference between the target position and the detected position, obtained by comparison result in said comparing step, is larger than a predetermined threshold value.