Copying apparatus and control therefor

Claim 1

In copying apparatus of the type including an exposure device, guide means operable to guide an original past the exposure device, switch operator means along the guide means actuated by an original, when the original is within the zone of the exposure device, to operate a switch contact arm, a stack holder for copying sheets, withdrawing means associated with the stack holder and operable to withdraw a top sheet from the latter, a reproduction device, copy sheet processing means, transpoRt mechanism operable to transport copy sheets along a transport path past the reproduction device and through the processing means, an intermittently operable copy sheet feed and contact pressure roller in the transport path downstream of the stack holder, and a continuously operable transport roller cooperable with the feed and contact pressure roller; the improvement comprising, in combination, copy sheet position detecting switch means in the path of the copy sheet immediately downstream of said feed and contact pressure roller and said transport roller cooperably therewith; drive means driving said transport mechanism and said transport roller in synchronism with each other; clutch means operable to connect said drive means to said withdrawing means for driving the latter in a copy sheet withdrawing direction; a freewheeling device included in said clutch means and providing for free movement of said withdrawing means in the copy sheet withdrawing direction; said position detecting switch means determining a ready position of a copy sheet in said transport path; electrically energized clutch operating means effective, when energized, to engage said clutch means; a first energizing circuit for said clutch operating means normally closed by said position detecting switch means and opened, to disengage said clutch means, upon operation of said position detecting switch means by a copy sheet in said ready position; means operable by said switch contact arm, responsive to actuation of said switch operator means by an original, to effect actuation of said feed and contact pressure roller from a rest position into a working position wherein it is driven in synchronism with said transport mechanism to feed a copy sheet, in said ready position, into engagement with said transport mechanism; a second energizing circuit for said operating means closed by said switch contact arm, responsive to such actuation by said switch operator means by an original, to reengage said clutch means to drive said withdrawing means; said feed and contact pressure roller having a configuration such that, in conjunction with said transport roller, it defines, in its rest position, a gap to receive the leading edge of a copy sheet in said ready position, and such that, when in its working position, it grips a copy sheet between itself and said transport roller to feed the copy sheet into engagement with said transport mechanism; said feed and contact pressure roller reattaining its rest position, to re-form said gap, immediately upon engagement of the copy sheet by said transport mechanism, to release the trailing edge of the copy sheet in said gap; and transmission means, between said drive means and said withdrawing means, having a reduction ratio such that, upon engagement of said clutch means, said withdrawing means is driven at a copy sheet feed rate less than that of said feed and contact pressure roller, with the feed rate difference being compensated by said freewheeling device; whereby, simultaneously with actuation of said feed and contact pressure roller into its working position, said withdrawing means is driven to transport the next copying sheet to said ready position.