Patent ID: 8576461

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 document sheet being conveyed on a feeding path, wherein the first image reading unit is configured to start sending a first analog signal corresponding to the image read by the first sensor when the first image reading unit receives a first start signal; a second image reading unit comprising: a second sensor configured to read an image on a second side opposite to the first side of the document sheet being conveyed on the feeding path; and a second converter configured to convert a second analog signal corresponding to the image read by the second sensor into a second digital signal, wherein the second image reading unit is configured to start sending the second digital signal when the second image reading unit receives a timing signal after the second image reading unit receives a second start signal; and a processor configured to: send the first start signal to the first image reading unit; send the second start signal to the second image reading unit; continuously receive a first analog signal from the first image reading unit; convert the first analog signal into a first digital signal at predetermined time intervals; send the timing signal to the second image reading unit while the processor is not converting the first analog signal into the first digital signal; and receive the second digital signal from the second image reading unit while the processor is not converting the first analog signal into the first digital signal.