| 摘要 |
PROBLEM TO BE SOLVED: To detect conveyance speed at a desired position on a conveyance path of a piece of paper as instant velocity.SOLUTION: A paper speed detecting device includes: an optical sensor 47a including a light receiving part 47a-1 in which a plurality of light receiving elements 47a-3 are arranged in a certain direction, and a light emitting part 47a-2 for radiating detection light to the light receiving part 47a-1; an optical sensor 47a outputting a light detection signal of the light receiving part 47a-1; a movable piece 47b provided in the vicinity of the optical sensor 47a on a conveyance path of recording paper P to move or change its orientation in a direction of an array of the light receiving elements 47a-3 to shade the detection light when pressed by the recording paper P in a conveyance state; and a computation control unit specifying rate of change of detection voltage shown by the light detection signal as the conveyance speed of the recording paper P. |
