Patent ID: 8837013

Claim:
An image reader comprising: a first image reading unit comprising a first sensor configured to read an image on a first side of a first document sheet being conveyed on a feeding path, and output a first analog signal corresponding to the read image of the first side; a second image reading unit comprising: a second sensor configured to read an image on a second side of the first document sheet being conveyed on the feeding path, and output a second analog signal corresponding to the read image of the second side; a first analog-digital converter configured to convert the second analog signal output from the second sensor into a first-order digital signal, and output the first-order digital signal; and a differential transmitter configured to convert the first-order digital signal output from the first analog-digital converter into a second-order digital signal for differential transmission, and output the second-order digital signal in a differential transmission method; and a control board comprising a processor, the control board configured to process the first analog signal output from the first sensor of the first reading unit and the second-order digital signal output from the differential transmitter of the second image reading unit.