Patent GB-1032956-A (GB)
Title: Improvements in or relating to sheet feeding apparatus
IPC: B65H3/06
Filed: 1962-12-28
Abstract: 1,032,956. Feeding sheets. RANK XEROX Ltd. Dec. 28, 1962 [Dec. 28, 1961], No 43030/65. Divided out of 1,032,951. Heading B6B. Sheet separators and guides.-Sheets are separated from the top of a stack, supported in a tray 60, by friction rollers 61 mounted in arms which are secured to a torque tube which is oscillated to move the rollers into and out of engagement with the stack, and stop means are arranged between the torque tube and the means for driving the rollers 61 whereby the duration of rotation of the rollers in contact with the stack during sheet separation is related to the height of the stack of sheets. The tray 60 and the means associated therewith for preventing double-feed of sheets therefrom are as described in Specification 1,032,958. The invention is described as applied to the xerographic reproducing apparatus described in Specification 1,032,951. Two separator rollers 61 are secured to a shaft SH9 rotatably mounted in two arms 249, 252, Figs. 5 and 11 (not shown) which are secured at their opposite ends to a torque tube 253 rotatably mounted on a shaft SH8. The shaft SH9 is coupled to the shaft SH8 by belt and pulley means 256- 258, and a pinion 266 secured on the shaft SH8 meshes with a toothed quadrant 267 secured to a shaft which is rocked by a cam 273 secured on the main drive-shaft SH1. Thus the rollers 61 are driven alternately in two opposite directions. The rollers 61 are raised from the sheet stack when they are reversely rotating, by means of a lever 264, Figs. 12-15 (not shown), fixed to the torque tube 253, which is pivoted to a link 276 connected to one end of a two-armed lever 277 having a follower 278 engaging a cam 281 on the drive-shaft SH1. The cam 281 has a null portion which is only engaged by the follower 278 when the rollers 61 fall low enough to engage the base of the tray 60 for the sheet stack, i.e. when the stack is depleted. An adjustment lever 291 pivoted on a fixed shaft is arranged to co-operate with a stop 269 carried by the toothed quadrant 267 to limit the throw of the quadrant in the direction which causes the rollers 61 to feed a sheet from the stack; the lever 291 has also a stop-screw 292 arranged to abut the end of the link 276 secured to the torque tube 253, so that the position of the link 276, and thus the height of the sheet stack, determines the position of the stop 269, which in turn determines the effective position of the toothed quadrant 267 at the start of an actual feed cycle for separating the sheets. With this arrangement, sheets from the top of a full stack are not fed the same distance as sheets from the top of a depleted stack. As shown in Fig. 7, the sheets are fed from the stack upwardly within a guide 67 where they are buckled against a gate 311. The guide comprises two inclined plates 301, 306 fixed to the machine frame, and egress from these plates is normally prevented by the gate 311. Stack and sheet registration.-The stack is registered by the pivotal front gate 231 of the tray 60 before the tray is slid into operative position, and by the depending portions 216, Fig. 9 (not shown), of the springs 221 when the tray is in operative position, as described in Specification 1,032,958. The sheet separated from the top of the stack and fed between the guide plates 301, 306, is buckled against a spring-urged pivotal gate 311 which is lowered when grippers 63 on chains 321 strike an extension of the gate. The gate 311 can also be opened by a lever 313. Sheet-forwarders.-Each separated sheet is taken by grippers 63 on one of two bars carried by a pair of endless chains 321 mounted on sprockets 322 and 323, Figs. 3 and 5 (not shown), and one chain is driven by a sprocket 27 which has a diametral pitch equal to the diameter of a drum 20 to which the sheet is fed, so that the linear speed of the sheet and the peripheral speed of the drum are equal. The grippers are opened at the sheet-taking and sheet-releasing positions. A paper-guide roll 335, having notched discs 336 thereon is mounted on the shaft SH3 carrying the sprockets 322; a similar guide roll 66 co-operates with a delivery roll 65 to feed the sheets from the machine.