Patent ID: 11905137
Assignee: CANON KABUSHIKI KAISHA
Field: Handling (Mechanical engineering)
Classification: CPC B | IPC B

Claim 10:
11. A sheet feeding device comprising:
a first feeding roller pair rotatable in a sheet nipping state and configured to feed a sheet;
an upstream feeding roller pair provided upstream of said first feeding roller pair with respect to a sheet feeding direction and configured to feed the sheet;
a downstream feeding roller pair provided downstream of said first feeding roller pair with respect to the sheet feeding direction and configured to feed the sheet;
a second feeding roller pair provided downstream of said downstream feeding roller pair with respect to the sheet feeding direction and configured to feed the sheet;
a first reading portion provided so as to extend along the sheet feeding direction on a side downstream of said first feeding roller pair and upstream of said downstream feeding roller pair with respect to the sheet feeding direction and configured to read an image of a leading end portion of the sheet fed by said first feeding roller pair;
a second reading portion provided so as to extend along the sheet feeding direction on a side upstream of said first feeding roller pair and downstream of said upstream feeding roller pair with respect to the sheet feeding direction and configured to read an image of the trailing end portion of the sheet fed by said first feeding roller pair; and
a controller configured to perform calculation depending on the images read by said first reading portion and said second reading portion,
wherein when the image of the leading end portion of the sheet fed by said first feeding roller pair is read by said first reading portion, the trailing end portion of the sheet passes through said upstream feeding roller pair,
wherein when the image of the trailing end portion of the sheet fed by said first feeding roller pair is read by said second reading portion, the leading end portion does not reach said downstream feeding roller pair,
wherein said controller calculates a sheet feeding speed on the basis of a fifth time which is a difference in timing between a plurality of images read by said first reading portion and a fifth distance which is a difference in position of the leading end portion of the sheet between the plurality of images,
wherein said controller calculates a length of the sheet on the basis of a sixth time which is a difference in timing between the image read by said first reading portion and the image read by said second reading portion, and
wherein said controller controls a sheet feeding timing by said second feeding roller pair on the basis of information of the length of the sheet.