Patent ID: 8622641

Claim:
A document-feeding roller mechanism adapted for conveying a document through a printing module, the document having a trailing end, said document-feeding roller mechanism comprising: a frame body including an upright plate having a first side surface that is adapted to face the printing module, and a second side surface opposite to said first side surface, and two side plates extending from said second side surface of said upright plate, each of said side plates being formed with a guide slot; a feeding roller assembly including a roller frame disposed rotatably on said frame body, a first roller unit disposed on said roller frame and adapted to be adjacent to the printing module, and a second roller unit in contact with said first roller unit so as to allow for movement of the document between said first and second roller units and toward the printing module; and a clamping-force adjusting module including a resilient pressing unit disposed on said frame body and providing a biasing force to said roller frame for biasing said first roller unit to contact said second roller unit, a cam unit disposed between said side plates, adjacent to and connected to said resilient pressing unit and rotatable relative to said frame body between a first angular position and a second angular position such that, when the trailing end of the document is moved to a position adjacent to and disposed upstream of said feeding roller assembly, said cam unit is controlled to rotate from the first angular position to the second angular position so as to reduce the biasing force of said resilient pressing unit on said roller frame and, thus, the clamping force of said first and second roller units to the document, and an elongated movable member disposed between said upright plate and said cam unit and having two opposite ends extending respectively and movably into said guide slots in said side plates, such that said movable member can be driven by said cam unit to move toward said upright plate, and can be biased by said resilient pressing unit to move away from said upright plate.