| 摘要 |
PURPOSE:To reliably feed a sheet regardless of the thickness of a sheet by setting the position of the uppermost sheet on a tray at a suitable height in such a manner as to be kept at a suitable distance from a transport belt corresponding to the thickness of a sheet. CONSTITUTION:According to an output signal of control means, a shut-down valve 24 is opened, and sucking force is worked upon the uppermost sheet 1a on a tray 2 by adsorbing means 40. Certain time later, the sheet 1a is adsorbed to a transport belt 3. At this time, the pressure in a duct 22 is remarkably decreased to open a valve 50, so that contact points 52, 53 are separated from each other. The time from opening of the valve 24 to the separation of the contact points 52, 53 is measured, and the tray 2 is moved up and down to position the sheet 1a at a suitable height according to whether the measured time is longer or shorter than a reference time previously set corresponding to the thickness or rigidity of the sheet. |
