JPS647764A - Image reader - Google Patents

Abstract

PURPOSE:To reduce load on an operator and to eliminate error in inputting the coordinate of a partial read area by providing a coordinate input element to read a part of an arbitrary square area in an original, and disposing linear positional sensors consisting of a piezoelectric film and a resistor sheet as coordinate input elements on both vertical and horizontal side surfaces of an original glass. CONSTITUTION:In the end parts in both vertical and horizontal directions of the original glass 1 of an image reader, the piezoelectric positional information input elements 100, 200 are respectively mounted. These elements 100, 200 are of a sandwich-constitution of the piezoelectric wire 300 and the resistor sheets 310, 320. The upper surface of the sheet 310 is pressed with an indicating tool 30 whose tip is pointed, and the variation in the resistance value of the pressed point is detected by means of the amplifiers 110, 210 of an electrical circuit and a switching circuit 150, etc. The variation in the resistance value between the sheets 310, 320 is made linear, while the resistance value (r) between A and C is made proportionate to the distance (x) from the A to the pressing point P, and the resistance value (r) is measured to detect the coordinates of the point P.