Patent ID: 9682579
Date: 2017-06-20
CPC Classifications: B41J

Claim:
1. A medium transporting state detecting device comprising: an irradiation optical system which irradiates a sheet-shape medium to be transported with non-coherent light; a light receiving optical system which receives diffuse reflected light of the non-coherent light from the medium; a diffuse reflected light acquisition unit which acquires an intensity of the diffuse reflected light for each constant period; a frequency component analyzing unit which performs analyzing a frequency component for each of a plurality of reflected light intensity arrays configured of arrays of an intensity in a time period where the intensity is temporally and sequentially shifted, among the intensities of the diffuse reflected light which are acquired over a plurality of periods; a period calculating unit which obtains an actual period of a temporal change in a real number portion of a frequency component of a specified frequency among the analyzed frequency components; and a velocity detecting unit which obtains at least one of a difference between an actual velocity of the medium and a target velocity and the actual velocity based on the actual period and the target period which is a period of the temporal change in the real number portion of the frequency component of the specified frequency in a case where a transporting velocity of the medium is the target velocity.