Patent ID: 6418274
Filing Date: 2002-07-09
Classification: B41J,H02P

Abstract:
A motor control apparatus for detecting a motor velocity, comprising:a signal generator producing a first pulse signal proportional in cycle to a motor velocity and a second pulse signal proportional in cycle to said motor velocity and different in phase from said first pulse signal is about one quarter of a single cycle; a pulse edge detector distinctively detecting leading edges and trailing edges of said first and second pulse signals from one another; a time counter measuring a period of time between the pulse edges in the same direction of the same pulse signal; a velocity converter using the period of time measured by said time counter to sequentially convert it into said motor velocity and thereby detect said motor velocity; a comparison reference value memory storing comparison reference values determined for each of the pulse edges, from the one preceding by a specific number of the pulse edges to a target edge which is a pulse edge indicating a targeted stop position of an object to be driven by said motor, to said target edge; and a motor stop controller comparing the comparison reference value with said motor velocity for each of the pulse edges from the pulse edge preceding by said specific number to said target edge so as to give a command to stop said motor when said motor velocity is equal to or over said comparison reference value.