IMAGE READER

PURPOSE:To read a transmission document with high precision by providing a means which aligns the optical axis of a first scanner having a transmission light source and that of a second scanner having a photoelectric converting means. CONSTITUTION:A CPU 51 moves a first scanner 3 from a home position H to a read origin Q by a scanning motor 10. It moves a second scanner 4 to this side of the origin Q by a scanning motor 27. The output of a photoelectric transducer 22 at this time is subjected to A/D conversion by an A/D converter 59 and is stored. Next, the scanner 4 is moved ahead of the origin Q by the motor 27, and the output of the transducer 22 at this time is subjected to A/D conversion 59 and is stored. The CPU 51 detects maximum information out of stored transmitted light information and moves the scanner 4 to the position corresponding to this information. Thus, the scanner 4 is set to the position corresponding to the optical axis of the scanner 3. That is, it is set to the position where the optical axis of an illuminating lamp 6 as the transmission light source and that of the transducer coincide with each other. Consequently, a transmission document is read with high precision.