Patent ID: 7414760

Claim:
An image reader, comprising: a plurality of photoelectric transducers each of which converts a light signal received from an image, into an electric signal, and includes an output portion which outputs the electric signal to a signal line common to the photoelectric transducers; a plurality of channel selecting switches each of which is connected to a corresponding one of the photoelectric transducers and selectively connects, and disconnects, the output portion of said one photoelectric transducer to, and from, the signal line; and a resolution selecting portion which receives, from an external device, (a) a control-start signal which commands the image reader to start controlling the channel selecting switches, and continues to take a predetermined voltage in a first predetermined time duration, and (b) each one of a plurality of clock-pulse signals which have respective different numbers of characteristic portions or portion in a second predetermined time duration falling in the first time duration, and said each of which has a plurality of pulses in a third time duration following the second time duration, the channel selecting switches being sequentially controlled in synchronism with the pulses of said each clock-pulse signal in the third time duration, so as to sequentially connect, and disconnect, the respective output portions of the corresponding photoelectric transducers to, and from, the signal line, the resolution selecting portion selecting, based on the number of characteristic portions or portion of said each clock-pulse signal, a corresponding one of a plurality of different reading resolutions corresponding to a plurality of different control patterns, respectively, so that the channel selecting switches are sequentially controlled according to the control pattern corresponding to the selected reading resolution, in synchronism with the pulses of said each clock-pulse signal in the third time duration.