| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately and inexpensively detect the existence of an original or the size thereof. SOLUTION: This reader is provided with a read glass 2 obtained by placing the original at the upper surface, a read light source 8 arranged at the lower position of the glass 2, a transparent conductive coating layer 7 coating the glass 2, a conductive member 6 arranged at the surface of an original pressing plate 3, which is arranged above the glass 2, opposed to the layer 7, a means impressing a voltage either of the layer 7 or the conductive member 6 and a detection part 10 detecting the change of a resistance value between the layer 7 and the conductive member 6 occurring when the original 9 is inserted. When the analog voltage E is impressed on the detection part 10 from the layer 7, it is converted to a digital signal by a next A/D conversion part so that it can be discriminated with some threshold value as a boundary whether the original exists or not. Then, the information thereof is given to a scanner control part so as to control whether a scanning action by the light source 8 is executed or not.</p> |
