Patent ID: 7907872

Claim:
An imprinting apparatus for imprinting an image onto a recording medium when the recording medium passes through a pressure-contacting nip, comprising: a stepper motor serving as a driving source; a pulse generating unit serving to control a frequency of a pulse signal driving the stepper motor; an image supporting member driven by the stepper motor; and a pressure-contacting member that includes at least a rotating body that contacts the image supporting member with pressure at the pressure-contacting nip; wherein a driving current supplied to the stepper motor is temporarily increased with reference to a driving current during usual rotation when a first transitional load fluctuation causing a transitional torque fluctuation occurs at one of the image supporting member and the rotating body by the recording medium entering and the pressure-contacting nip and a second transitional load fluctuation causing a transitional torque fluctuation occurs at one of the image supporting member and the rotating body by the recording medium leaving the pressure-contacting nip such that an angular fluctuation of the motor becomes less than a predetermined threshold defined in view of quality of image with reference to a position fluctuation of images at a peak value of the transitional torque fluctuation, and the driving current is increased before the first transitional load fluctuation occurs, and the driving current is increased after said second transitional load fluctuation, and changes in the driving current before and after said load fluctuations are gradually performed in order to reduce an amount of a position gap generatable when imprinting images on the recording medium, where the reduced amount is less than a predetermined threshold defined in view of an allowable quality of image.