Luminous quantitative adjustment manner null of paper leaf detection

摘要

PURPOSE:To achieve a longer maintenance period without erroneous detection of sheet papers, by providing an emission level varying circuit which allows a light receiving circuit to obtain the optimum emission level for detecting the presence or non-presence of the sheet papers accurately, varying the intensity of the emitted light. CONSTITUTION:First, an automatic adjustment start signal 7 is turned ON to only control an automatic adjustment circuit 6 of a sheet paper detector which make a judgment of non-presence of sheet papers among a plurality of sheet papers detectors by a light receiving circuit 5. Then, an emission level varying circuit 1 is adjusted to lower the emission level by one rank than the current value and it is determined whether a judgement of presence of sheet papers is made or not. When the judgement of the presence of sheet papers is given despite the fact that there is no sheet papers with the emission level lowered by one rank, a light emitting element 3 and a light receiving element 4 are fouled, from which it is judged there is no room for the emission level. On the other hand, when there is no sheet papers, the emission level is checked whether to be within an adjusting range or not and when it is within the range, the emission level is lowered sequentially by one rank and this operation is repeated until the presence of sheet papers is determined. When it is determined to be outside the range, the emission level is raised by one rank.