an automatic document feeder to adaptively adjust the nip force between the follower roller and the driving roller in response to input and output of the paper sheet there effectively preventing the paper sheet from getting jammed the ejecting roller assembly includes a swing lever a follower roller a friction generating element and a driving roller the swing lever is coupled to the follower roller for adaptively adjusting the nip force the friction generating element is arranged between the swing lever and the follower roller for facilitating increasing the friction force between the swing lever and the follower roller the driving roller is used for controlling input and output of the paper sheet application_number US 75414907 A description referring to fig3 a schematic cross sectional view of an automatic document feeder according to a preferred embodiment of the present invention is illustrated the automatic document feeder 300 principally includes a paper input tray 302 a paper ejecting tray 304 a pick up roller assembly 310 a transfer roller assembly 320 an inner roller assembly 330 an ejecting roller assembly 340 a first transfer path 350 and a second transfer path 360 the ejecting roller assembly 340 includes a swing lever 342 a follower roller 345 a friction generating element not shown and a driving roller 348 the swing lever 342 includes a first end 343 fixed to the automatic document feeder 300 and a second end 344 coupled to the follower roller 345 hereinafter a process of adaptively adjusting the nip force between the follower roller 345 and the driving roller 348 in response to input.