Patent ID: 9336589
Filing Date: 2016-05-10
CPC Classification: B42C,B65H,G06T

Claim Text:
1. A sheet feeder feeding sheets one by one to a book binding machine from a sheet stack formed of a plurality of individual sheet bundles each of which corresponds to a book block composed of collated sheets, and stopping the sheet feed temporarily whenever the sheet feed of one sheet bundle is completed, the sheet feeder comprising: a frame; a shelf attached to the frame so as to move in a vertical direction with the sheet stack placed thereon; a vertical alignment plate attached to the frame, arranged adjacent to the front end of the shelf and opposite to the front face of the sheet stack on the shelf; a first conveyance unit attached to the frame and arranged above and opposite to the uppermost sheet of the sheet stack on the shelf and configured to convey uppermost sheet forward beyond the alignment plate by engaging with or sucking the uppermost sheet; a second conveyance unit attached to the frame, arranged at the downstream of the first conveyance unit and configured to receive the sheet from the first conveyance unit and discharge the sheet to the book binding apparatus; a control unit comprising a controller configured to control the movement of the shelf and the operation of the first and second conveyance units, wherein the first conveyance unit starts conveying the next sheet whenever the previous sheet is discharged from the second conveyance unit; a memory in which images of predetermined printed areas of the first or last sheets of the sheet bundles are preliminarily stored as reference data; and a camera supported by the frame and arranged above the sheet stack on the shelf so as to take an image of the uppermost sheet of the sheet stack within a range of the sheet corresponding to the predetermined printed area, wherein the image of the sheet obtained by the camera is compared with the reference data, and when the obtained image of the sheet agrees with the reference data which is the image of the predetermined printed area of the first sheet, operation of the first conveyance unit is stopped temporarily, and when the obtained image of the sheet agrees with the reference data which is the image of the predetermined printed area of the last sheet of the first conveyance unit is stopped temporarily after the such sheet is discharged from the second conveyance unit.