Patent ID: 8678385

Claim:
A sheet conveying device comprising: a first conveying roller for conveying a sheet; a second conveying roller for conveying said sheet on a downstream side of said first conveying roller; a detection sensor for detecting a leading end of said sheet in a leading-end detection position on the downstream side of said second conveying roller; a first leading-end position output unit for outputting first positional information on the leading end of the sheet; and a controller for controlling drive states of said first and second conveying rollers respectively, based on not a detection state of said detection sensor but the first positional information on the leading end of said sheet, which is outputted from said first leading-end position output unit, wherein said first leading-end position output unit is configured to: update the first positional information on the leading end of said sheet by adding a feed amount of said sheet conveyed by said first conveying roller; stop the update of the first positional information on the leading end of said sheet when said detection sensor does not detect the leading end of said sheet, and the first positional information on the leading end of said sheet as updated by adding the feed amount indicates that the leading end of said sheet arrives at a position on an upstream side of said leading-end detection position; and resume the update of the first positional information on the leading end of said sheet with said leading-end detection position as a starting point when said detection sensor detects the leading end of said sheet after the update of the first positional information on the leading end of said sheet has stopped.