An image reading apparatus can inhibit image disturbance and density unevenness. The image reading apparatus includes a first conveyance roller pair, a back side image reading unit, a second conveyance roller pair, a front side image reading unit, a third conveyance roller pair, and a control unit. The control unit compares the image data read by the back side image reading unit and the image data read by the front side image reading unit to calculate a relative magnification variation there between, corrects the reading time of the front side image reading unit for each line based on the calculated relative magnification variation, and performs, in accordance with correction of the reading time, image correction of the image data of the front side image reading unit which has been corrected with respect to the reading time.

Disclosed is a method of determining line feed error in an image forming apparatus for printing an image, said image forming apparatus comprising a print head having a head sensor configured to sense information from the image printed on a print medium, said method comprising the steps of printing a first swath of the image on the print medium, repositioning the print head relative to the print medium by at least one line feed distance, determining a line feed error based upon information sensed from the printed first swath by the head sensor, and printing, using the determined line feed error, a second swath of the halftone image on the print medium.

Disclosed is a method of determining line feed error in an image forming apparatus for printing an image, said image forming apparatus comprising a print head having a head sensor configured to sense information from the image printed on a print medium, said method comprising the steps of printing a first swath of the image on the print medium, repositioning the print head relative to the print medium by at least one line feed distance, determining a line feed error based upon information sensed from the printed first swath by the head sensor, and printing, using the determined line feed error, a second swath of the halftone image on the print medium.