Abstract

A facsimile document scanner 10 is illustrated which includes an optical system 23 having a folded optical path 40 and an adjustable lens system 42. A test pattern 60 in the form of a plurality of alternate light and dark stripes 64, 66 is focused upon a linear photodiode array 50 mounted in an integratd circuit pack 51. The number of light and dark stripes 64, 66 is equal to the number of photodiodes in the linear photodiode array 50 across the document width. For adjustment purposes, an oscilloscope 70 is connected to a serial output from the integrated circuit pack 50 and the position of the lens system along the optical path 42 is adjusted and a corresponding adjustment is made to the pointer of the lens holder 45 within the lens housing 43 to obtain the desired image size and focus. The position of the diode array 50 is adjusted with respect to the focused image 72, 74 to obtain the maximum display amplitude.