LIGHT AMOUNT DETECTOR, MISALIGNMENT AMOUNT DETECTOR, AND IMAGE DENSITY DETECTOR

PROBLEM TO BE SOLVED: To enhance detection precision by suppressing a regular reflection light of a noise component in a diffusion light sensor from being received, and by preventing a sensor output to a patch in a direction opposite to a direction of offset from being slightly different. SOLUTION: This light amount detector includes a light emitting element 110 for emitting a light toward a detection pattern 131 formed on a face 130 to be detected of an image carrier, a photodetection element 120 for detecting a diffusion light from the detection pattern irradiated with the irradiation light, and a light amount detecting means for detecting received light amount, based on a detection output from the photodetection element. In the light amount detector, one of the light emitting element 110 and the photodetection element 120 is provided at a position directly opposite to the detection surface 130, such that a distribution of sensitivity of the photodetection element 120 detecting the diffused light is substantially symmetrical with respect to a detection output peak when the detection surface 130 is substantially parallel to a hypothetical line connecting the light emitting element 110 with the photodetection element 120. COPYRIGHT: (C)2009,JPO&INPIT