| 摘要 |
PURPOSE:To make it possible to detect the abnormality of detection parts for detecting whether a sheet-like object exists on a sensor target or not by providing this sheet-like object measuring instrument with the 2nd logic part for outputting an on-sheet signal at the time of inputting an on-sheet signal from at least one of the detection parts. CONSTITUTION:An AND circuit 43 to be the 1st logic part outputs an on-sheet signal at the time of inputting on-sheet signals from both of optical switch photodetectors 42. An OR circuit 44 to be the 2nd logic part outputs an on-sheet signal at the time of inputting an on-sheet signal from at least one of the photodetectors 42. A measurement control part 22 allows a selection part 45 to select the signal outputted from the AND circuit 43 at the time of measurement to detect the existence of paper on sensor targets 31, 41 based upon the on-sheet signal outputted from the AND circuit 43. At the time of checking the abnormality of the optical switches 42, the control part 22 allows the selection part 45 to select the signal outputted from the OR circuit 44 and judges the abnormality at the time of inputting the on-sheet signal from the selection part 45. |
