| 摘要 |
A pair of infeed rollers located upstream of an exposure window and a pair of outfeed rollers downstream thereof transport an original across the exposure window so that successive portions of the transported original be imaged onto successive portions of copying medium whose transport speed corresponds to that of the original. The lower infeed and outfeed rollers are stationary, but the upper ones are located at the coupling links of a four-or five-link transmission mechanism comprised of cranks and rockers. A tension spring tightened by an electromagnet causes the upper infeed roller to move down and press against the lower infeed roller. Due to the transmission mechanism, variations in the thickness of an original transported between the infeed rollers inherently modified in a controlled manner the force of the upper outfeed roller against the lower and/or the spacing of the upper outfeed roller from the lower, so that an original transported across the exposure window by the infeed rollers not collide with the outfeed rollers. Intermediate successive copying operations, the roller pairs open, so that an endless original, such as a computer print-out, can be reverse transported by a distance at least equal to the transport-direction length of the exposure window, to form upon successive sheets of copying medium successive images which adjoin to form a gapless image of the endless original.
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