GB2058023A - Defining sets of sheets - Google Patents

Abstract

In apparatus in which sheets are separated from the bottom of a first set in a tray whilst a second set is being stacked thereabove, a removable set separator (201), locatable between the sets, is provided. A shaft (206) that supports the separator (201) has one end portion resting on a cam member (210) whereby actuation of a solenoid (202), when the first set is empty, propels the separator (201) along the cam surface (210) and away from underneath the second set of copies to a stop position. A spring (203) biases the shaft (206) and separator (201) from the stop position to a position on top of the second set of copies in order to separate the second set of copies from the next set of copies coming into the tray. <IMAGE>

Description

SPECIFICATION Set separator apparatus and method This invention relates to sheet handling apparatus and methods and more particularly to set separators for use in sheet feeders where the feed tray contains sheets from more than one set at the same time.

Such separators find use in duplex copying systems for maintaining job integrity during duplexing and also in recirculating document sheet handlers for counting the number of set circulations and thus the number of sets copied.

Duplex copying systems that employed copy set storage means in the past have used set separators, bottom feeders and duplex return transport means to achieve the duplex function. Bottom sheet feed devices have been employed as duplex buffer set trays in the past and have included pressurized air to reduce friction between the bottom sheet and the sheet stack tray and minimize friction between the bottom sheet and sheets immediately adjacent thereto. Problems encountered during the use of such systems included some misfeeding of sheets which reduced reliability of the systems and tended to discourage their use because one would not have an indication when a misfeed occurred and therefore, would not know whether the output of the copier included a complete set of duplexed copies or not.

Set separators are also used in recirculating document sheet feeders in which sheets are fed from the bottom of a stack in a feed tray and returned to the top of the stack for refeeding to permit precollation copying. Here the separator is positioned overlying the set during feeding to separate the sheets being fed from those returned to the tray. The separator is then repositioned over the stack of returned sheets which may now be recirculated. By sensing the completion of a set circulation, the separator can be used to count the number of sets copied. It can also be used to detect misfeeds by counting the number of sheet feeds during each circulation and comparing this with the number of sheet feeds during the first circulation.

Various prior art structures are known for controlling copying systems including U.S. Patent 3,588,472, issued November 1966 to Thomas H. Glasteret al, which discloses a system wherein the number of record sheets entering a transport path of a reproduction apparatus are monitored along with the number of copies egressing from the transport path.

The respective numbers are compared with the number of copies desired and this comparison is utilized to set up or set down a reversible counter means to indicate the number of original documents from which the requisite number of copies have been made, completed, and delivered to a sorting area. Edward G. Reehil et al. in U.S. Patent 3,944,794, issued March 16, 1976, discloses a copying system that employs counters in order to automatically produce a programmed number of copies in a copying machine in the event a malfunction occurs before the program is completed. U.S. Patent 3,819,266, issued June 1974 to Harry C.Price, shows a copying system incorporating means to stop the system in the event of a jam and the RESEARCH DISCLOSURE of May, 1978 on pages 27-29, Item No. 16938, shows a separator drive mechanism for an automatic document handler.

The RESEARCH DISCLOSURE of June, 1977 on pages 33-34, Item No. 15842, shows a separator return means for use in recirculating feeders and Technical Disclosure T964008 shows a separator employed in a document feeding apparatus.

U.S. Patent 4,116,558 issued September26, 1978, shows set separators that rotate in a horizontal plane employed in a buffer tray for duplex purposes.

From one aspect the invention provides a set separator for a sheet feeder for separating sheets of a first set being fed from the bottom of the tray from sheets of a second set being delivered to the top of the tray, said separator including an arm positioned overlying the first set during feeding thereof and which following feeding of the last sheet in the first set is repositioned overlying the second set, and means actuable upon feeding of the last sheet in the set for withdrawing said arm from beneath the second set so that it is guided along an upwardly inclined first path past a gate and then returning the arm so that it is guided along a second path and is repositioned above the tray overlying the second set.

From another aspect the invention provides a set separator for a feed tray comprising multiple positioning separator means mounted on a shaft and adapted when in a first position to separate a first set of substrates from a second set; linkage means having forward and rear ends connected to the shaft at the forward end; solenoid means connected to the rear end of said linkage means; and ramp means adapted to guide said separator means to a second and non-separating position when said solenoid is actuated.

From a further aspect the invention provides a method of separating sets of copies in the tray of a copying machine comprising the steps of: a) providing a set separator member for separating a first set of substrates from a second set of substrates; b) moving said separator member after a first set of substrates have been fed into the tray rearward and upward without dropping below the first set of substrates to a non-separating position; and c) moving said separator member in a curvilinear arc out from said non-separating position to a position on top of substrates in place to be fed from the tray.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which: Figure lisa side view of a bi-directional xerographic copying system with collated copy sheet output in accordance with the present invention; Figure 2 is a side view taken along line 2-2 of the automatic document handling apparatus shown partly cut away in Figure 1; and Figure 3 is the present invention shown in a perspective view taken along line 3-3 of Figure 1.

Referring to Figure 1, there is shown a schematic illustration of an exemplary reproduction machine 10 that employs a set separator and counter duplex tray means that will accomplish the objectives of the present invention. It includes a conventional photoconductive layer or light sensitive surface 21 on a conductive backing and formed in the shape of a drum which is mounted on a shaftjournaled in a frame to rotate in the direction indicated by the arrow to cause the drum surface to pass sequentially a plurality of xerographic process stations. It should be understood that belt photoreceptor and flash exposure could be used instead of the photoreceptor and exposure means in Figure 1.

For purposes of the present disclosure, the several generally conventional xerographic processing stations in the path of movement of the drum surface may be described functionally as follows: a charging station A at which the photoconductive layer of the xerographic drum is uniformly charged; an exposure station B at which a light or radiation pattern of a document could be reproduced is projected onto the drum surface to dissipate the drum charges in the exposed aras thereof, thereby forming the latent electrostatic image of a copy to be reproduced; a developing station C where xerographic developers are applied to the photoconductive surface of the drum to render the latent image visible; a transfer station Dat which the xerographic developer image is electrostatically transferred from the drum surface to a transfer support material;; a drum cleaning station Eat which the drum surface is brushed to remove residual toner particles remaining thereon after image transfer; and a fusing station F at which point the image is fused to the copy paper for support material.

For copying, the xerographic apparatus 10 disclosed herein projects an image from the automatic web scroll document handling apparatus 30 described in U.S. Patent 3,963,345, issued to D. Stemmle and M. Silverberg, which disclosure is incorporated herein by reference.

The document images are projected through lens 50 down from mirror 28 of Figure 1 onto the photoreceptor 20. The image is developed on the photoreceptor surface 21 and rotated clockwise to a transfer station D. Copy sheets coming from either the main copy sheet feeding tray 90 or the auxiliary sheet feeding tray 91 are fed by a series of sheet feeding rollers to the transfer station D in order to accept the developed image from the photoreceptor drum 20 at the transfer station D. Vacuum stripping means 65 strips the paper from the photoreceptor 20 and transports it toward fuser F so that the image can be fused onto the copy sheet. Thereafter, the copy sheet is transported either to duplex tray 300 or to an output sheet tray 151 or 152. For simplex copies, the duplex tray or holding means 300 is not utilized.Documents can be imaged in the apparatus of Figure 1 either from the automatic document handlerorfrom platen 26.

For uni-directional document copying, all of the sets will be in one output tray. The same output tray 151 is used whether the copies are simplex or duplex. Collation occurs without an inverter. For bi-directional copying, alternate sets are ultimately placed in trays 151 and 152. The forward order copies go into tray 151, and the reverse order copies go into tray 152.

As shown in Figure 2, documents are loaded by being placed onto web 33 against registration means 81 while scroll 31' is in the load/unload position. As the documents are moved by the automatic document handler (hereinafter called ADH), they are exposed to light directly from exposure lamp means 70 and reflected through reflector means 71 off the document into a bi-directional optical system for projection of the document image onto photoreceptor 20. Each sheet is conveyed passed exposure means 70 and reflector means 71 and wound onto, scroll means 32 after scroll means 31 has been moved into recirculation position. Subsequently, scroll means 32 is reversed in direction toward scroll means 31 to allow re-exposure of documents wound around in a reverse scan mode.

Forthefirst exposure of the document on page images on the web, only even numbered documents are imaged, i.e. documents located in the 2,4,6,8, etc. positions on web 33. Depending on whether uni-directional or bi-directional copying is desired, the buffer set is a one-set or two-set buffer, respectively. For uni-directional copying, a fast reverse rewind is accomplished and only one buffer set is required. For bi-directional copying, the even numbered documents are also imaged during reverse movement of the web to create two-buffer sets, one in ascending order (2,4,6...) and one in descending order (8, 6,4,2). In either case, copies made from exposure of the even numbered documents are fused at station F and continued in transportation on a conventional conveyor system into buffer set counter tray means 300.

It is within the set counter duplex tray area that the present invention resides in that documents in the ADH are imaged, even numbered documents first on a forward pass of the ADH with the images obtained from the documents being transferred to copy sheets fed from copy sheet tray 90. Afterthe images have been transferred at station D, the one-side imaged sheets are then forwarded toward duplex tray 300. In order to keep job integrity, it is necessary to count sheets of paper or one-sided copies as they come into the duplex tray and count the copies as they egress from the duplex tray.The number of copies in must equal the number of copies out before set separator memberorflag means 201, which was retracted as the first set of copies was fed into the tray and subsequently allowed to rest on top of the first set of copies and thereby separate them; from any incoming copies, will retract and allow the next set of one-sided copies to fall into the bottom of the duplex tray 300 in order to be refed for duplexing.

In accordance with one aspect of the present invention, a complete set or book counted into tray 300 causes solenoid 202 to become energized which in turn pushes its plunger against the counterforce of spring 203 and lever 204 which is connected through shaft 205 to cantilevered shaft 206. Shaft 206 supports separator member 201. The activation of solenoid 202 through the movement of shaft 206 moves flag 201 along cam surface 210 into a stop area (shown by dashed line). The flag is only at the stop area momentarily since de-energization of solenoid 202 allows spring means 203 to propel shaft 206 in a curvilinear arc along cam surface 220 with separator flag 201 ultimately coming to rest on what is now the leading edge of the copies, i.e. or top of the set, in the duplex tray.Sheets of the following book or set can now continue to be fed into the duplex tray, at the same time copies of the first book are being fed out of the tray. If machine logic counts the same number of sheets of the first book fed out as were fed into the tray, the solenoid 202 is actuated to retract separate member 201 and allow the second set to drop into place for feeding by the vacuum feeder means 301. If a double feed has occurred, the logic would not actuate the solenoid because a full count had not been reached in the required time, and a machine shut-down would occur.While set separator 200 is shown in Figure 1 above the bottom of buffer tray 300, it should be understood that it could be located at the bottom of tray 300 with flag 201 being retracted after a first set of copies have been fed into the tray and guided to a position on top of the set of copies in the tray in order to separate that set of copies from a second set of copies.

A programmable machine controller, preferably of the type as disclosed in U.S. Patent 4,144,550 which is incorporated herein by reference to the extent necessary for the implementation of the present invention, is used to control the operation of xerographic reproduction in either the simplex or duplex modes of copier 10. The controller includes appropriate logic for counting the number of copies entering the duplex tray, counting the number of copies exiting the duplex tray, comparing the two counts, and means for actuating solenoid 202 to retract set separator means 201 and allow a first set of copies to fall into feeding position while controlling actuation of the solenoid for a second set of copies only when there is coincidence between ingress copies and egress copies from the duplex tray. Also, conventional counters and circuitry as disclosed in U.S.

Patent 3,588,472 to Thomas Glaster et al., issued June 1971, could be used to carry out the invention as disclosed herein and is incorporated herein by reference as would be necessary to perform the present invention.

Now referring more specifically to the apparatus of the present invention and Figure 1, it can be seen that duplex tray means 300, as well as vacuum feed means 301 and transport means 64, are controlled by machine control means 101 with the transport means 64 and vacuum feed means 301 being actuated in response to the completion of a set of one-sided copy sheets entering duplex tray means 300 to feed the set of copy sheets back toward transfer station D. On succeeding passes of the automatic document handler, forward and reverse, all documents are imaged with copy substrates being fed from the copy sheet tray 90 to transfer station D alternately with copy sheets fed from feeding means 301.Copy sheets fed from primary copy sheet tray 90 receive images of even positioned documents in the ADH and are fed to buffer tray means 300 while copy sheets that are fed from feeding means 301 alternate with the sheets fed from the primary copy sheet tray and receives images on the reverse side thereof of odd positioned documents in the ADH and are fed to output station 151 for copy sets made on the forward pass, or station 152 for copy sets made on the reverse pass, so that once a completed, collated set of documents have been collected in the output station, they may be stapled and side stacked or staggered, and they will still read in consecutive ascending order, for instance, 1, 2, 3,4, 5, 6, etc. On the last pass of web 33 past the exposure station 70, only odd numbered or positioned documents are imaged.The images are then copied on the back of copies previously made from even numbered documents that are fed by feeding means 301. This process empties the feeding means 301 and presents the final set of duplexed copies to the output station. However, if a two-set buffer is used, i.e., if the ADH imaged documents on both the forward and reverse scans, odd numbered documents (only) are imaged on both of the final forward and reverse scans of web 33 in order to make complete duplexed copies of the.

two sets of evens adapted for feeding by means 301 in order to finish the duplex run of collated sets with an empty transport means 64 and feeding means 301.

It should be understood that odd numbered documents could be imaged on the first pass of the ADH, however, to do so would require an extra pass of the last copy sheet through the transfer station without putting an image on the even side thereof in the copying of an odd numbered document set, e.g.

a set of 5 documents. Various other ways of using the machine disclosed in use with the present invention are disclosed in U.S. Patent 4,116,558 issued September 1978, which disclosure is incorporated herein by reference as is necessary for the implementation of this invention.

In reference to Figure 2, an optical system for scanning documents in both directions of relative reciprocal motion between the documents and the optical system is shown. The document is first scanned in one direction, then the image orientation is rotated 180 about the axis of propagation for scanning in the reverse direction. Properly oriented images are thus projected onto photoreceptor 20 and move in the same direction during both directions of scan, i.e., moving in the same direction as the photoreceptor surface in both cases without reversing the photoreceptor movement. This is more fully disclosed in U.S. Patent 4,008,958, issued February 22, 1977.

Referring now to Figure 3, the advantage of the present invention of providing a low cost, simple and compact set separator is shown. Job integrity in the present duplex copying system is maintained with the use of machine controller 101 by counting the number of one-side imaged copies 100 as they come into duplex tray 300. The copies initially come to rest against set separator member 201 which is adapted for translation by shaft 206 to a retracted position (shown in broken lines). When a complete set of copies is counted, solenoid 202 is actuated by controller 101 and serves to push spring 203 and lever 204, which is attached to shaft 206 through shaft 205. Shaft 206 is slidably attached by gravity to stationary cam surface 210 and supports separator member 201.Energization of solenoid 202 rotates set separator member 201 through lever 204 and shaft 206 to retracted position 215 and allows the completed set of one-sided copies to fall into feeding position adjacent vacuum feed means 301. Afterwards, the solenoid is de-energized and the separator member travels over cam surface 220 to assume its non-retracted position on top of the copy set.

In movement, flag 201 is pulled outfrom under the bottom of the copy set, lifted up behind it and moved in aforward direction back out over the top of the set. While the guide cam surfaces for shaft 206 are shown separate and curved, it should be understood that the same surfaces could be replaced with an enclosed loop or race track design, if desired.

One-side imaged copies of the next set can now continue to be fed into tray 300 and rest against set separator member 201 at the same time sheets are being fed from tray 300 by feeding means 301. If controller 101 counts the same number of copies of the first set fed out was fed in, set separator member 201 is retracted by solenoid 202 and the second set of copies fall into positionforfeeding. If a misfeed occurs, machine controller 101 will not energize solenoid 202 and the separator member will not retract.

In conclusion, a duplex copying system is disclosed in which page images are formed on both sides of copy sheets by copy processing means one side at a time to form multiple copy sets. Set separator means according to the present invention is employed in the duplex tray of the disclosed copier and is responsive to machine logic through a controller 101 to separate one set of copies from another set. Machine logic counts the number of sheets coming into the duplex tray and the number of sheets going out of the tray. The number of sheets in, must equal the number of sheets out before the set separator means will be retracted along a curved cam surface away from the bottom of the copy set and subsequently allowed to travel along a second curved cam surface to a rest position on top of a second set of copies now in position to be fed out of the tray.

As previously mentioned, a set separator according to the invention may also be used in a document sheet feeder for producing collated output copy sets.

Such feeders in which the sheets are recirculated travelling from the feed tray to an imaging station and back to the feed tray a plural number of times are well known and may be adapted for either or both simplex and duplex copying. For copying duplex document sheets, the sheets may be returned to the feed tray inverted during each alternate circulation although other procedures are possible.

An example of a recirculating document sheet feeder is to be found on the Xerox 5600 Reproduction Machine (Xerox is a registered trade mark). A description of a simplex duplex recirculating docu ment sheet feeder may, by way of example, be found in European Patent Application No 80 303 010.5.

Claims (11)

1. Asetseparatorfora sheet feeder for separating sheets of a first set being fed from the bottom of the tray from sheets of a second set being delivered to the top of the tray, said separation including an arm positioned overlying the first set during feeding thereof and which following feeding of the last sheet in the first set is repositioned overlying the second set, and means actuable upon feeding of the last sheet in the set for withdrawing said arm from beneath the second set so that it is guided along an upwardly inclined first path past a gate and then returning the arm so that it is guided along a second path and is repositioned above the tray overlying the second set.

2. A set separator according to claim 1, comprising a multiple positioning separator arm mounted on a shaft and adapted when in a first position to lie beneath a set of copies in the feed tray; linkage means having forward and rear ends connected to the shaft at the forward end; solenoid means connected to the rear end of the linkage means; ramp means adapted to guide said separator arm to a second position away from beneath the set of copies in the tray when said solenoid is actuated; and cam means adapted to guide said separator arm from said second position to a third position on top of the set of copies in the tray to thereby separate incoming copies from the copies already in the tray.

3. A set separator for a feed tray comprisirrg multiple positioning separator means mounted on a shaft and adapted when in a first position to separate a first set of substrates from a second set.

Iingkage means having forward and rear ends connected to the shaft at the forward end; solenoid means connected to the rear end of said linkage means; and ramp means adapted to guide said separator means to a second and non-separating position when said solenoid is actuated.

4. A set separator according to claim 3 including cam means adapted to guide said separator means from said non-separating position to a position on top of the next set of substrates to be fed out of the tray.

5. A set separator according to claim 4 wherein said cam means is pivotable to a first position to allow said separator means to reach said nonseparating position and subsequently to a second' position whereby said separator means is guided to the top of the set of substrates in the tray.

6. A set separator according to claim 2,3,4 or;5, wherein said linkage means is biased into said solenoid means by a spring means.

7. A set separator constructed, arranged and adapted to operate substantially as herein before described with reference to the accompanying drawings.

8. A method of separating sets of copies in the tray of a copying machine comprising the steps of: a) providing a set separator member for separating a first set of substrates from a second set of substrates; b) moving said separator member after a first set of substrates have been fed into the tray rearward and upward without dropping below the first set of substrates to a non-separating position; and c) moving said separator member in a curvilinear arc out from said non-separating position to a position on top of substrates in place to be fed from the tray.

9. A method according to claim 8 including the step of allowing said separator member as it completes its curvilinear movement to drop to the top of the substrates in the tray due to gravity.

10. A method according to Claim 7 or 8 or 9 including the steps of: a) counting the number of substrates fed into the tray; b) feeding substrates out of the tray simultaneously with feeding substrates into the tray; c) comparing for coincidence the number of substrates fed from the tray with the number of substrates fed into the tray; and d) moving said separator member only if coincidence is obtained.

11. Methods of set separation substantially as hereinbefore described with reference to the accompanying drawings.