Image formation apparatus having a diagnosing function

摘要

An image formation apparatus has detection signal generator for generating an analog detection signal, reference signal generator for generating an analog reference signal of a reference level, A/D converter for converting the analog signal into a digital signal, and controller for causing the detection signal to be input to the A/D converter and putting out a desired control signal and for causing the reference signal to be input to the A/D converter and determining the then magnitude of the digital signal to thereby detect abnormality of the A/D converter.