Abstract: A dish washing and drying machine according to the present invention determines the sequence of washing conforming the amount of dirt and the quality of dirt on the dishes and executes the same. This dish washing and drying machine finds the amount of dirt from a value MF stored in a buffer MF 47 storing transmittance detected by a transmittance detecting circuit 41. In this case, an output is corrected by a value ME stored in a buffer ME 46 and a reference voltage, to correct the amount of degradation of a light receiving element. In addition, the quality of dirt is found from a value MD stored in a buffer MD 45 and a value MC stored in a buffer MC 44. The sequence of processing is determined from the amount of dirt and the quality of dirt. Accordingly, washing can be done depending on not only the amount of dirt but also the quality of dirt, for example, whether dirt is caused by oil, proteins or the like. As a result, it is possible to sufficiently and completely wash the dishes.

Abstract: The control apparatus of the present invention is used for a washing machine in which a photosensor having a light emitting element and a light receiving element opposite thereto, detects the degree of light transmission in washing water, and in which, based on variations of the degree of light transmission in washing water thus detected, the respective steps of washing, rinsing and draining are controlled. Correction is made such that the photosensor presents a predetermined sensitivity to set a current which flows in the light emitting element, after which a washing operation is started. After drainage, when the next water supply operation is started and the level of water thus supplied reaches a predetermined level within a predetermined period of time, it is judged that washing water used at the previous washing remains in a washing tank. Then, control is made such that no adjustment is made of the sensitivity of the photosensor and a standard current flows in the light emitting element.