Patent ID: 6873804

Claim:
An image sensing device comprising: light source means; a recording member on which an image is formed, said recording member being conveyed in one direction; illumination means for causing a light beam emitted from said light source means to obliquely illuminate said recording member; and imaging means for condensing specularly reflected light from the image on said recording member and causing the reflected light to travel to a surface of light receiving means, said image sensing device obtaining positional information of the image on said recording member on the basis of a signal obtained by said light receiving means, wherein when the amount of displacement of the recording member in a vertical direction during conveyance of said recording member is d, an angle between the optical axis of said imaging means and a normal to said recording member is θ (degrees), and resolution of the image formed on said recording member is R (dpi), the components are set so that d· tan θ<(25.4 /R )×1000 is satisfied.