CA1077556A - Recirculating sheet feeder - Google Patents

Abstract

Abstract of the Disclosure A copier has an exposure platen on which a selected side of a sheet is images exposed for copying. For use with the copier, a recirculating sheet feeder removes sheets, stacked selected side upwardly, one at a time in succession from the stack bottom. Each sheet is fed in a single direction along a loop-like path, depositing selected side downwardly on the platen for exposure and returning selected side downwardly to the stack top. Consequently, an operator can load a multi-page document into the recirculating feeder before exposure, and remove it after exposure, with the pages arranged in a naturally appearing or rightside up orientation.
Owing to the efficient compact design of the feed path, and by maintaining the sheet feeding members continuously in motion during sheet movement along the feed path, the recirculating feeder is capable of a relatively high recirculating speed.

Description

~775S6 CROSS REFER~NCE TO RELATED APPLICATIONS
~eference should be had to commonly assigned, copending Canadian Patent Application Serial No. 210,239, entitled~ SYNCHRONIZING CONTROL APPARATUS FOR ELECTROPHOT0-GRAPHIC APPARATUS UTILIZING DIGITAL COMPUTER, filed 27 September 1974, in the names of W, E', Hun~ et al, CKGROUND OF THE I~ENTION
Field of the Invention t The present invention relates to document copying.
10 More specifically, this invPntion relates to a shee~ eeding apparatus for serially feeding the indi~idual pages of a multipage document which ~s to be copied from a supply tray to an exposure platen for copying, and for re~urning such pages ~o the supply tray for either removal or another feeding cycle.

: DESCRIPTION OF THE PRIOR ART
Where it is desired to make several copies of a mul~ipage original, providing copies which have the same page order or sequence as the original, each page of the 20 original may be copied the required number o times in its proper page order and the resulting page copies appropriately collated, To facilitate this manner of copying, ~he prior art, as for example U,S D Patent No. 3,747,918, patented July 24, 1973, discloses a sheet feeder which feeds individual sheets in succession from the top of an originating stack to an exposure platen o~ a copying machine. At the exposure ~'`'' ~

1al77556 platen, a sheet is exposed the required number of times and then is expelled from the s~eet eeder. The resulting copies oE ~he `
sheet rnay be Eorwarded from the copier to a collating machine which, in turn, rou-tes the sheet copies to respective collator bins. ~fter each of the sheets have been Eed ~rom the stack and copied, each collator bin will contain a single complete copy of the stack, with the sheet copies arranged in the same order as the sheets originally in the stack.
Al~hough the sheet feeder in U.S~ Pat~ No 3,747,918 allows for collated copies of a multi-page original, it must be used with some kind of a collator, which increases both the com-plexity and e~penseof the copying opera~ion. hlternatively, each page of the original may be copied once i~ the order or se-quence in which it appears There results a single copy o the original, having each page arranged in the same order as the ; original. This manner of copying can be repeated as many times as required to provide the desired number of copies of the oriOinal without employing a collator. However, such an approach is best served by providing some device for automatically handling the 20 pages of the original to repeatedly present each page at the ex-posure platen in the proper sequence and at the proper time.
This device has gene~ally taken the form of a recirculating sheet feeder, which feeds indi~idual sh~ets in succession from the bot tom of an originating stack to the exposure platen and returns them singly to the top oE the stack in their original orientation.
After each of the sheets have been fed once~ they can be either fed again or removed from the feeder. By this apparatus, which is disclosed for example inu.s. Re.27~976~pa~en~ed April 23, 1974~ r several copies of a mul~i-page original can be d21ivered from the copier with their respective pages in the same order. Such a result is achleved because the sheet feeder maintains the proper page order of the original after cornpleting each copy cycle. Of course, should the copy pages be dellvered from the copier in the same order as the original pages,collation of the copy pages is unnecessary.
To facilitate the discussion which follows regarding known recirculating feeders, it will be convenient to refer to these feeders as (i) a reversing or bidirectional kind, and (ii) a non-reversing or unidirectional kind.
The reversing kind of a recirculating feeder is disclosed f'or example in U.S. Patent No. 3,556~512, patented January 19, 1971. According to this reference, individual sheets are fed in succession from the bottom of an originating stack to a waiting area proximate an exposure platen of a copier. A sheet transport, in the form of an endless feed belt overlying the exposure platen, is driven forwardly to draw a sheet onto the platen. To position the sheet in registration with the platen for exposure, the belt is re-versed, i.e. driven backwardly~ feeding the sheet backwardlyinto abutment against a retractable registation stop member.
Then, the sheet is exposed in place on the platen. The feed belt may be stopped during exposure or it may continue to move backwardly, slipping on the sheet (at that time prevented from backward movement by the registation member). After exposure~
the registation member is retracted and the feed belt, moving ~ backwardly, expels the sheet frorn the platen. Then, the sheet ; is returned to the top of the originating stack. After one . ~ sheet has been expelled from the platen by moving the belt ~ 30 backwardly~ the belt is again reversed, moving forwardly to t ~ draw another sheet onto the platen. It will be realized that ~',,"' .
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1~77556 each time the feed belt is reversed, it must be brought to a halt and started again. This stopping and restarting o~
the ~eed belt gives rise to several typical mechanical problems, for example, involving the backlash and inertia of the belt and the belt driving members. ~ Moreover, by thi~ stopping and ~ restarting Or the feed belt, there is a delay in sheet movement, ; and consequently a delay in the copy cycle. Such a delay may ; be further increased because, in the re~ersing -recirculatin~
feeder, it appears that one ~heet must be expelled completely from the exposure platen before another sheet can be initially drawn thereon.
Another recirculating feeder, the non-reversing kind, is disclosed for example in U.S. Pat. No. 3,552,739~ patented Janu-ary 5, 1971, and in Ger. Pat. No. 1,128,295, patented April 19, 1962~ This recirculatLrlg feeder, as disclosed, appears to ob-viate some o~ the disadvantages of the reversing recirculating feeder mentioned above; because here, the sheets, during recircu-lating movement between the originating staek and the exposure platen, are ~ed in a single or forward direction (rather than in forward and reverse dir2ctions). This is accomplished ~y feeding the sheets aLong a feed path which is substantially in the form of a closed loop With sheet feeding in a single direction, it will be realized that there is not required any reverse-movement of a feed belt or other sheet transport. However, it is to be noted that in each of the U.S. and Ger. patents certain ones of ~ the transport members are repeatedly stopped and restarted. For ex ; ample, in the Ger. patent, an image-bearing sheet and a photosensi-tive sheet are fed separateLy from originating stacks into abut-ment against a retractable stop member. The stop member serves to ` 30 align the sheets at their forward, leading edgec. Then apparently, ii a pair o~ initlally stationary rollers are rotated and pivoted to-,, .

;. _,,_ .. ..

~C377S56 ward each other in~o con~act with ~he sheets, and at the same time the stop member is retracted, allowing the rollers to feed the sheets to an exposure platen, Thereafter, the rollers are pivoted away from each other and their rota~ion discontinuedO
On the other hand, in the U.S. patent9 t~o separa~e endless feed belts, which serve ~o feed the sheets respective'ly from and back to an origina~ing stack, are inac~ivated dur~ng the time that another endless feed belt slides a sheet across an exposure platen for scanning exposurev The repeated s~opping and re-starting of a sheet transport in bo~h the U.SO and Germanpatents may give rise to several mechanical problems, examples of which are mentioned above. Moreover, there may be caused a delay in the copy cycle because a stopped transport, before again feeding a sheet, must overcome its inertia and resume a feeding speed similar to that of other activated or running transport means so as to reduce the possibility of sheet -;
tearing.
While U.S. Patent NoO 3~552,739 and German Patent NoO
1,128,295 are considered as each disclosing an sxample of a recirculating feeder for the purpose of this description o~ the prior art, it is to be noted that, in these patents, the copies are delivered from the copier w~th their respective pages in a different order than ~he page order of the original~ Con-sequently, collation of the copy pages is necessaryO
A further disadvantage of ~he non-reversing recirculating feeder in German Patent NoO 1,128~295 is that the copying apparatus, includIng th~ exposure pla~en,is located inside (rather than outside) of the loop~like path of sheet movement. This would seem to pre~ent use of tha~ re-circulating feeder with many new copiers, such as the kind inU.S. Patent No. 3,552,739~ which is an automatic xerographic .

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: ~077556 reproducing machlne. Moreover, by enlarging the loop-like path to encircle the copying apparatus, the travel time of ~ a sheet between the originating stack and the exposure platen ; is increased. One further disadvantage, in the German Patent, is that the exposure platen is located well within the copying -~ apparatus, raising the possibility of " losing" a sheet during movement to and from the exposure platen because of a sheet -~ jam, for exa~ple.
. -~ .
Beside ~causing some delay in the copy cycle by repeatedly stopping and restarting a sheet transport, known reversing and non-reversing recirculating feeders typlcally require that a multi-page orlginal be loaded into each feeder, and removed from the feeder, in an upside down or reverse orientation. It will be realized that in this orientation the sheets are ~andled~by an operator wlth their respective sides selected for copying facing downwardly in a stack.
Therefore, it is difficult for the operator to view the selected side of each sheet without invertlng the stack.' For this reason, handling a multi-page original in an upside down orientation is inconvenient and less desirable than handling ; the same original in a natural or rightside up orlentation.
; ~; Moreover, by stacking the sheets in a feeder with their s, ~
' respective sides selected for copying facing downwardly, the operator may not be able to determine, by looking at the stack :; . . .
during the copy cycle, whlch of the sheets have been copied i and returned to the stack and which of the sheets remain to be - copied. This is exemplified by the recirculating feeders in U.SO Patent Nos. 3,552,739; 3,556,512; Re. 27,976; and ln ~ ~ German Patent No. 1,128,295. There, during the copy cycle, ? -the sheets are stackedlwith their respective sides selected for copying facing downwardly. As a result~ should the opposite ,s ~

~ -7-16317~5~6 ,., , ' ' ' , sides of these sheets be blank, the operator, by looklng at the stack, cannot determine whether or not the topmost sheet has already been copied. On the other hand, in -these patents, were the operator to stack the sheets selected side upwardly, copying would not be possible because each sheet would be deposited on the exposure platen with its selected side facing away from the platen during exposure.

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As distinguished from known recirculating feeders, the recirculating feeder here described receives a multi-page original in a natural or rightside up orientation and enables removal!f the multi-page origlnal, after copying, intact in the natural orientation. Another distinction is that the feeder avoids causing a delay in the copy cycle~
by maintaining its sheet feeding means continuously (rather than intermittently) in motion during recirculating movement of the sheets between an originatlng stack \and an exposure platen. And owing to its uniquely designed sheet feed path, the feeder is capable of a relatively high recirculat:Lng 20 speed.

With the recirculating feeder described, the stacked ,. . .
., ~.~ sheets are in their original order and orientation after ~ ~
f~
f ~ copying. Moreover, the sheets are loaded into the feeder, ~;;.1 and removed from the feeder after copying, with their respective ~ sides selected for copying facing upwardly in the stack. As ;~ a result, a multi-page original can be handled by an operator `` as it normally appears, i.e. in a rlghtside up orientation, , ~ - with the first page in view. This is due~ in essence, to . . ' '~ 30 the manner of sheet feeding. Specifically, a sheet feed path ,.
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~77S56 .
is de~ined by which sheets stacked selected side upwardly ~n a supply tray are removed from the stack bottom, deposited selected side downwardly on an exposure platen and returned selected side upwardly to the stack top, in the proper sequence.
Because the sheets are returned in the proper order selected side upwardly to the stack top, the operator, by looking at the topmost sheet in the originating stack during the copy cycle, can determine which of the sheets have been exposed and which remain to be exposed. - -The sheet feed path can be subst~ntially . , .
in the form of a single closed :
loop, with the exposure platen located outside this loop.
Such an arrangement enables the recirculating feeder to be used with many of the recently devised copiers; an example of which ls disclosed in Canadian Pa~ent Application Serial No.210,239 , more fully referenced herein before. Further the supply . tray can be located directly above (though spaced from) the exposure platen. By this f`eature, a particularly compact and efficient loop shape is reallzed, enabling a relatively ` high recirculating speed.
During a typical feeding operation? the sheets are . ; fed seriatim in a single direction along khe feed path, exiting selected side upwardly from the supply tray at the stack bottom, depositing selected side downwardly on the exposure platen, and returning selected side upwardly to the supply tray at r ' ~. the stack top. Each of the sheet feeding means, for this ~ ; purpose, is maintained con-tinuously in f`eeding motion during ~ -. .
sheet movement along the feed path. Consequently, there is no delay in the copy cycle, as caused by repeatedly stopping ~- and restarting any of the sheet feeding means. Where it is ,, _ g _ ~

1~775S6 desired to hold the sheet staionary during exposure on the platen, a retractable registation member is provided for mom~ntarily blocking sheet movement at a platen end farthest removed along the feed path from the supply tray. Moreover, sheet propelling means, such as several feed rollers, are located within the loop adjacent to the platen for ~eeding sheets selected side downwardly past the platen. These rollers are continuously rotated ln contact with a sheet lying on the platen; however, they slip on the sheet during blockage by the registation member. By continuously rotating the rollers in contact with ~he sheet during registation and exposure, the high speed capability of the recirculating feeder is further enhanced. After each of the sheets in the originating stack have been fed once, they can be either fed agaln or removed from the feeder. ~ccordingly, several copies of the multi-page original can be delivered from the copier with their respective pages in the same order and orientation as the original, and consequently do not have to be collated. This result is achieved because the recirculating feeder of the instant invention preserves the proper order and orientation of the orlginal after each copy cycle.

More particularly in accordance with one aspect of the invention :' ~ there is provided a process for recirculating seriatim the individual pages of 'i a multipage document supply tray and an exposure platen at which each document .,, ~
page is exposed for the purpose of forming a copy thereof, said process being characterized by the fo~lowing steps:
:, . .
r~,' (a) supporting the individual pages of the document in a stack ~:~ spaced from the exposure platen in such a manner that the side to be copied ., of each document page faces upwardly; and '. ' 30 (b) successively advancing the bottom-most page of the stack . .
along a closed loop path to present each document page to said exposure platen with the side to be copied facing downwardlyl and to return the document page -- O--~377556 to the top of the stack with the side to be copied ~acing upwardly.
In accordance w~th a second aspect of the invention there is `
~rcv~ded an apparatu~ for recirculating seriati~ the indivi~ual page~ of a multipage document between a document supply tray and an exposure platen at which each document page is exposed for the purpose of forming a copy thereof, said apparatus being characterized by:
(a) a tray for supporting the individual pages of the document in a stack spaced from the exposure platen in such a manner that the side to be copied of each document page faces upwardly; and (b) means for successively advancing the bottom-most page of the stack along a closed loop path to present each document page to said exposure platen with the side to be copied faeing downwardly, and to return the docu-, ment page to the top oE the stack with the slde to be copied facing upwardly.
The tray may be posltioned direct~y above ~he exposure platen and the advanc-lng means may comprlse guide means defining a closed loop path with a portion ~ ;
of the path being exteriorly adjacent the platen. The advancing means may further comprise a plurality of rotatably mounted feed rollers with drive r: ~ means for rotating the rollers continuously during advance~ent of the document pages alon~ the path. The advancing means may include page propelling means for maintaining driving contact with a document page during exposure.
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BRIEF DESCRIYq'ION OF THE DRAWINGS
, For a more complete understanding of the instant invention, as well as the advantages and features thereo~, reference should be had to the ~ollowing detailed description ~. of the invention taken in conJunction with the accompanying $~.~ drawings, in which:
Fig. 1 is a schematic front elevation view of an electrophotographic copier, equlpped with a recirculating feeder according to a preferred embodiment of the present . ; 30 invention;

-lOa-3,(3 7~5~6 Fig. 2 is an enlarged ront elevation view, par~ly in section, of the recirculating feeder;
Fig. 3 is a top plan view of the recirculating feeder as viewed along ~he line 3-3 in Flgo 2;
Fig. 4 is a top plan view of the recirculating feeder as viewPd along the line 4-4 in Figo 2; and Figo 5 is a perspec~ve view of a drive mechanism ln the recirculating feeder.
DESCRIPTION OF I~IE PREFERRED EMBODIMENT
It may be well before proceeding with a detailed description of the preferred embodiment to firs~ consider an electrophotographic copier with which such an embodimen~ may ~ be ~sed. Although the preferred embodiment is particularly i well suited for use in an electrophotographic copier, it could be used with equal facility and advantage in any number of other copying, duplica~ing or reproducing machinesO All that ~ i is desired is that such a m~chine have a platen or equivalent , . ..
support on which successive sections of sheet m~terial can be ; placed for copyingO This sheet material may be in cut, fan- -~jl 20 folded or endless loop form, for exampleO
Electrophoto~raphic Copier Referr~ng now ~o the drawings and in par~icular to Fig. 1, there is schematically illustrated an electrophoto-~` graphic copier, designated generally by the reference numeral lo Only those features of ~he cop~er which are helpful for a full ~- understanding of the preferred embodiment are described herein~
after. However, a more complete description of ~he copier may I be found in U,S. Patent NOD 39914,047, patented on October 21, 1975~
To copy a selec~ed side C of an original sheet S, using the copier 1, the original 3heet is placed wi~h the selected side facing downwardly on an exposure pLa~en 2 ~-.~., , ~1:377~5~
. ~ .

constructed of transparent glass. When energized, two xenon rla~h lamps 3 and 4 illuminate the. selected side C o~.the.
original sheet S; whereupon, a light image of the selected side is reflected back from the exposure platen 2, and projected ; as an inverse or mirror image onto a discrete section Or a photoconductive web 5 by means of an object mirror 6, a lens 7 and an image mirror 8. The photoconductive web 5 has a photo-conductive or image receiving surface 9~ with a transparent support backing, and is trained as an endless or continuous belt about six transport rollers 10~ 11, 12, 13, 14 and 15. At least one of these rollers is driven to move the web 5 sub-; ' stantially in a clockwise direction, ~ndica~ed generally by an arrow 16. This movement wlll cause successive sections of the web 5 to sequentially pass a series of electrophotographic . work stations. .For the purposes of the instant disclosure, j ~ :
the several work stations along the path of movement of the ~
I !.;.
,"~ web may be described functionally as follows:
a charging station 17, at which the photoconductive surface 9 of the web 5 is sénsitized by receiving a uniform electrostatic charge;
an exposing station 1~, at which the inverse image .. of the selected side C of the original sheet S is proJected i onto the photoconductive surface 9 of the web 5, dissipating the electrostatic charge at the exposed areas of the photo-s ~:
conductive surface and forming a latent electrostatic image thereon which corresponds inversely to the lndicia on the selected side of the original sheet, a developing station 19~ at which developing powder, including toner particles having an electrostatic charge opposite to that of the latent electrostatic lmage, is brushed over the photoconductive surface 9 of the web 5, causing the toner partlcles to adhere to khe latent electrostatic image and visibly form a toner particle or developed image which is a mirror resemblance of the indicia on the selected side C .
of the original sheet S;
a postdevelopment erase station 20, at ~hich the web 5 is illuminated to reduce photoconductor fat.i.gue, i.e.
its inability to accept or hold an electrostatic charge;
a transfer station 21, at which the developed image : is electrostatically transferred from the photoconductive .-surface 9 of the web 5 to a receiving side C' of a copy :
:::. sheet S' (movement of the copy sheet being checked by a ;r, registration device 22 to assure its arrival at the transfer :
~ station, from either one of two supply bins 23 and 24, $.~ coincidently with the arrival of the developed image at -the transfer station);
a cleaning station 25, at which the photoconductive " -i surface 9 of the web 5 is cleaned of any residual toner particles remaining thereon after developed image transfer and is substantially completely discharged of any residual `~
- 20 electrostatic charge remaining thereon.
.. ; The developed image, as transferred onto the copy sheet S', ) :~
has the same indicia configuration as that on the original . sheet S. After recei*ing the develop.ed image at the transfer - station 21, the copy sheet S' separates from the web 5 at the roller 14~ and is carried by a vacuum transport 26 to a fusing station 27. The fusing station 27 serves to fix the developed image by fusing the toner particles to the receiving side C' of the copy sheet S~. Then, the copy sheet S' ls mo~ed through a guide and feed roller arrangement 28, coming 30 to rest in a completed copy tray 29. As depicted in Fig. 1, ' -13- .

~7~556 :
the copy sheet S' ls deposited in the copy tray 29, fixed image or recelving side C' facing upwardly, and on top of an earlier similarly deposited copy sheet.
To coordinate operation of the varlous work stations 17~ 18, 19, 21 and 25 with movement of the image areas on the web 5 successively past these stations, the web has a plurality of perforations, not shown, along one of its edges and there is provided, at a fixed location along the path of web move-ment, suitable means for sensing the web perforations. This sensing generates input signals which are fed into a digital computer, not shown. The digital¦computer has a stored program, responsive to the input signals, for sequentially actuating and de-actuating the work stations in properly timed relation ~ with movement of the web's image areas to and from these stations.
; , Recirculating Feeder !- The preferred embodiment of a recirculating feeder, `~ according to the present inventionS is designated generally by the reference numeral 50 in Fig. 1. With this feeder 50, , a plurality of sheets can be repeatedly fed in succession from:"
~' 20 an originating stack to the exposure platen 2 of -the electro- \
~` photographic copier 1. This is done by returning the sheets to the originating stack in the same order or sequence as they are fed therefrom. To operate the feeder 50 in coordinated assocation or synchronism with the copier 1, the feeder includes suitable means, as is known in the art, for providing "go"
and "no go" signals to the ditigal computer in the copier. These signals are indicative of the various "ready" and "not ready"
conditions occurring with respect to sheet feeding in the feeder, and enable the digital computer to properly sequence each of the related work activities in the feeder and the copier. Examples of these sensing means in the feeder 50 appear in the description which follows.

~c97755~

Fig. 1 shows a front view of the recirculatlng feeder 50, which is positioned directly on top of the exposure platent 2.
For access to the exposure platen 2, the recirculating feeder 50 is raised, at a front end 51 thereof, causing the entire feeder to pivot about a rearwardly located connection, not shown, with the copier 1. Particular details of the recirculatin~ feeder 50 are shown in Figs. 2-5. As illustrated in Fig. ~, the recirculating feeder 50 is loaded by placing an originating stack of sheets S
into a supply tray 52. The sheets S, stacked in the tray 52, are oriented with their respective sides C selected for copying facing upwardly. Referring to Fig. 3, the bottom-most sheet in the stack, which is the first to be removed fr.om the stack, is supported on several ribs 53 and the flat base portions 54 of two, otherwise up-standing, sheet edge guides 55. The ribs 53 and the base por-tions 54 of the edge guides 55 each project, to the same height, from the floor plate 56 of the tray 52. Consequently, for the :,~. ,, most part, an air space is provided between the bottom-most sheet in the stack and the floor plate which facilitates removal of the bottom-most sheet from the stack bottom. The edge guides 55 are mounted in respective slots 57 in the floor plate 56 for movement toward and away from each other to accommodate different width `::

- :.

: . . ' ,, , ' ',' ,~ ~ ", '.';' ', ' , ' ' '; ' ' sheet sets. The ribs 53 are arranged so as not to inter~ere with this movement of the edge guides 55. As vlewed in Fig. 2, the tray 52 is inclined downwardly to the right, causing the forward or leading edges F of the sheets S to rest in abutme~t against a forward wall plate 58 The rearward or trailing edges R
of the sheets S are spaced ~rom a rea~ard wall plate 5~ of the tray 52. During the feeding cycle~ in which the sheets S are re-moved from the stack bottom and returned to the stack top, an end ;~ jogger 60 and a side jogger 61 separately move back and forth to maintain the sheets aligned or squared with each other in the stack. As shown in Fig. 3, two openings 62 and 63 are provided respectively in the rear wall plate 59 oE t~Le tray 52 and in one of the edge guLdes 55 Eor passage of the end and side joggers 60 ... .
and 61. The end jogger 60 is movably ad?ustable to accommodate different length sheet sets. The side jogger 61 is mounted in a slot 64 in the ~loor plate 56 to enable its coordinated movement with the edge guides 55 during their adjustment for sheet width.
~ rotatably supported vacuum cylinder 65, as show~ in Fig. 2, extends partially into the space betl~een the floor plate 56 and the wall plate 58. The vacuum cylinder 65, which is hollow, is sealed excep~ for a single elonga~e series of air intake ports 66, shown in Fig. 3~ and an air out-take opening, not shownO
Suitable conduit and ~asket means, not shown~ connect the air out-take opening with a vacuum source, in the copier 1~ for draw-ing air from the cylinder interiorO Initially, the vacuum cyl-inderj65 is orienkated with the air intake ports 66 in a starting position located beneath the ~o~ward edge F o~ the bottom-most sheet ~ in the tray 52. Air rushing into the intake ports 66 causes this forward edge F to peel away from the stack .

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bottom and adhere to the vacuum cylinder 65. Then, the vacuum cylinder 65 is rotated slightly in a clockwis~ direction, as vlewed in F~g. 2, drawing the bottom-most sheet S from the stack only enough to deliver its forward edge F into respective feeding nips 67 defined by continuously rotating feed rollers 68 and back- ;.
up rings 69. The remaining sheets S are prevented from separating ~ from the stack.by the abutment of their fo~ard edges F with the wall plate 58~ The backup rings 69, shown in Figs. 2 and 3, ex- ~ -tend around the vacuum cylinder 65, rotating with re~pect , `` ~o to the vacuum cylinder and abou~ the same axis. ) ~.
;I As depicted in Fig ~, the backup rings 69, cooperate with the ~; eed rollers 68 to eect complete ~removal of t~e bottom-most . .
sheet from the stack and.to feed the removed sheet along an arcuate guide 70 to the exposure platen 2. As soon as the vacuum cylinder '1 . .
65 has delivered the forward edge of the bottom-most sheet into the feeding nips 67, it is reversed~ rotating slightly in a counterclockwise direction~ as viewed in Fig. 2, until the intake ports 66 are returned to thelr star~ing position. During this re-verse movement o~ the vac w m cylinder 65, the intake ports 66 inch rea~ardly along the bottom-most sheet as it is being drawn between the feed rollers 68 and t'ne backup rings 69. After the intake ports 66 hQve returned to their starting position, the rearward edge of this sheet clears them; whereupon~ there is a . renewed rush of air into the intake ports which peels the forward edge of the next appearing bottom-most sheet from the staek bottom and adheres lt to the vacuum cylinder 65. Then, the vacuum cyl-inder 65 is again rotated slightly in a clockwise direction, draw-ing the next appearing bottom-most sheet f~om the stak only enough to deliver its orward edge into the feeding nips 67. The feeding ., . ' '~.
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nips 67 recel~e the forward edge of this sheet upon departure of the rearward edge of the previous sheet from the feeding nips. Accordingly, by the sequence Just described, each of ;~ the sheets S are removed one at a time in succession from ;~ the stack~bottom and fed to the exposure platen 2.
As depicted in Figo 2, each sheet S exiting from ~i- the arcuate guide 70 is deposited onto the platen 2, in an ~; exposure position, with its side C selected for copying facing downwardly. Two sets of continuously rotating feed rollers ~; 10 71 and 72, as shown in Fig. 4, move the sheet S, selected side C
, downwardly, along the platen 2 and into registation therewith for exposure. During such registation, the sheet S lies stationary on the exposure platen 2 with its forward edge ~
in abutment against two registation pads 73, which are spaced ; ; apart from each other on a registation bar 74. As shown in Fig~ 2, the registation pads and bar 73 and 7LI are located at the platen end farthest removed along the feed path from the supply tray 52. Because the feed rollers 71 and 72 urge the sheet S against both of the registation pads 73~ any skew in the sheet is corrected before it is expcsed. Feed rollers 71 and 72 and the registration pads 73 depend through respectlve openings 75, 76 and 77 in a backup plate 78. This plate 78 extends substantially parallel to the platen 2. On the side 79 of the plate 78; which faces the platen 2, there is coated a light reflective material serving as a light shield during exposure. While the registration pads 73 block movement of the sheet Sg feed rollers 71 and 72 continue to rotate, slipping on the backside of the sheet. This slipping occurs for some fraction of a second (during the time the sheet is stationary) between registration of the sheet and its exposure. After exposure, suitable means such as a solenoid, : `:

; not shown, ls actuated to retract the registration bar 74 g with the registration pads 73, away from the feed path and out of the way o~ the sheet S. Then, as depicted in Fig. 2g the sheet S is immediately expelled by the rotating rollers 71 and 72 from the exposure platen 2 and onto an arcuate guide 80.
To again locate the registration bar 74, with the reglstration pads 73, as shown in Fig. 2 for sheet registration suitable ; - means are provided, though not snown~ to deactuate the re-tracting means in response to expulsion of one sheet from the ~^ 10 exposure platen and movement of another sheet thereon.
Because the feed rollers 71 and 72 continue to rotate during registation and exposure, there are none of `the previously described problems involving inertia, backlash or delay in sheet movement which might otherwise occur should these feed rollers stop~rotating before exposure and resume rotating in the same or opposite direction after exposure. It will be realized that this feature of continuously rotating the feed rollers 71)and 72 in contact with the sheet S during registration and exposure contribute~to the high speed capability of the recirculating feeder 50.
As shown in ~ig. 4, shafts 81 and 82 of the feed rollers 71 and 72 are not displaceable from the respective rollers' axes of rotation (except for an occasional ad~ustment o~ roller pressure, as is well known); and, therefore, are not movable to relieve roller pressure on the sheet S during the time that it lies on the exposure platen 2. However, the feed rollers 71 and 72 are constructed oflpolyurethene foam andg optionally, have a silicone rubber coating on the roller periphery. The silicone rubber coating increases the page propelling ability of each ~ I

feed roller, and the polyurethene foam allows successive radial sectors of each ~eed roller to slightly compress during contact with the sheet so as to relieve roller pressure thereon. Such a construction enables the feed rollers 71 and 72 to move the sheet S, .

~.~775S6 when called for, and to slip on the sheet's backslde durin~ ;
reglstration and exposure, without causing any arching or other deforming of the sheet.
As depicted in Fig, 2, each sheet S expelled from the platen 2 after exposure is mo~ed by the feed rollers ~.rom the . arcuate guide 80 to the arcuate guide 83. Approximately half- I
way along the arcuate guide 83, the sheet S (still being moved by the feed rolleYs72~ enters a feeding nip 84 defined by continuous- ¦
~ ly rotating feed rollers 85 and idler or pr~ure rollers 86. -These ¦
10 . rollers 85 and 86 cooperate to feed the shee~ S past an electro- .
static discharge device 87, which neutralizes any sta~ic electrlcal charge on the sheet before its return by the rallers to the origi-nating stack in the supply tray 52. When the sheet S exits ~rom .
. the arcuate guide 83, a finger member 88 deflects it dow~wardlyto the right, as viewed in Fig~ 2, depositing the sheet on the stack top with its side C seLected for copying fac;ng upwardly. I
The end and side joggers 60 and 61, which at this time are moving 1 back and forth, align or square each returning sheet with others.
in the stack~ Looking at Fig. 2, the end jogger 60 is faced with a plush materiaL 89 arranged with its fibers extending dow~wardly, ¦
to the right. When a sheet S is returned to the tray 52~ it enters II
from left to right, and then rebounds from right to left off the .
forward wall plate 58. The plush fibers 89 momentarily engage the rebounding sheet, which is then released to fall onto the stack I, top. This arrangement reduces the time required for the rebounding , sheet to become stabilized or squarely o~iented ln the stack~ and l~
assists in preventing that sheet from rebounding into another next I r arr~ving sheetO

Again re~erring to Fig. 2, there is shown a separator member 90 which e~tends~ throu~h the opening 62 in the rearward w~ll plate 59, into the orig~nating s~ack in the supply tray 52.

The sepa~a~or member 90, as viewed in Fig. 2, separates the sheets ~:
S in the stack which have been exposed and those which remain to be exposed, at their rearward edges R~ More specl.fically, the ;~
rearward edges of the sheets already e~posed lie above the separa-tor member and the rearward ed~es of the sheets awaiting exposure lie below the separator member. The separator member 90 is fixed to a rotatably supported shaft 91r Consequently~ during the ~eed~
ing cycle, as the sheets S are Eed in succession ~rom the st.ack bot~om to the exposure platen 2 and returned singly to the stack top, the separator member 90 rotates incrementally in a clocl~se direction, as viewed in Fig. 2, about the shaft 91. When the last one of the sheets ~o be exposed is ~ed ~rom the stack bottom, the separator member ~0 drops through an opening 92 in the ~loor plate 56 of the supply tray 52. Where two or rnore feeding cycles are :`:
required, as where severaL collated copies of a multi-page docu-ment are desired~ the separatQr member 90 is moved by suitable drive means, not sho~n, onto the topmost sheet in the stack. This is done, of course, a~ter the last one of the sheets to be exposed a ~rstt~e ~ returned to the stack top~ When the separator membe~ 90 drops through the opening 92 in the ~oor plate 56, a counter switch~ !

not shown~ is actuatedO This switch actuation is sensed by the digital computer in the copier 1, indicatingito the computer that a single sheet set has been copied. At the end of the copy ~ob, the computer recognizes concurrence between the number of sensed switch actuations and the number of sheet set copies re-quested by an operator; whereupon, the recirculating feeder 50 may be deactivated after the last one of the sheets to be finally exposed is returned to the stack top.

. ~77556 . With the recirculating feeder 50 according to the preferredembo ~ ent, it should be recognized that the sheets S are loaded into the supply tray 52 before copying, and removed from the supply tray after copying~ with their respective sides C selected for copying facing upwardly in the originating sta.ck. Accordingly, a multi-page document can be handled by an operator as it normally appears, i.e. in a rightside up orienkation, with the first page in view. This is due5 in essence, to the di.sclosed manner of - sheet feeding. ~pecifically, during the feeding cycle~ the sheets S
are fed seriatim in a single or forward direction along the feed path, éxiting selected side C upwardly from the supply tray 52 at the stac~c bottom, depositing se~ected side downwardly on the exposure platen 2, and returning selected side upwardly to the supply tray at the stack top. Because the sheets S are returned in the proper order selected side C upwardly to the stack top, the operator, by looking at the topmost sheet in the originating stack during the feeding cycle, can determine which of the sheets have been exposed and which remain to be exposed.
Another advantage is that the recirculatinglfeeder 50 prescrlbes the proper page order ancl orientation of the multi-page document after each complete copy cycle. Therefore, the operator can remove the multi-page document from the supply tray 52 after the copy cycle~ with the pages in their originating order and orientation. Then, the multi-page document can be stapled and returned to file for future use as required.
As will be realized by looking at Fig. 2 and from the description above, the feed path is substantially in the form of a single.closed loop, with the exposure platen 2 located .
exteriorly thereadjacentO The supply tray 52 is located directly above (though spaced from) the exposure platen 2.
By this arrangement, a particularly compact and efficient loop shape is realized which contrlbutes to the high speed .

~t77556~ :

capability of the recirculating feeder 50, Moreover, the recircula~ing feeder can be used with many o the recently :~:
devised copiers, such as disclosed in U.S. Patent NoO3,914,047 patented on October 21, 1975. :
Figs, 2 and 5 sh~w ~he drive mechan~sm for continu-ously rotating feed rollers 68, 713 72 an~d 85 during sheet :~
vement along the eed pathO Looking at Fig. 5, a drive motor ~ :
93 serves to move an endless drive belt 94; rotating a fly wheel 95, a drive shaf~ 96 and two side-by-side drive pulleys -:
97 and 98. Rotation of the drive pulley 97 moves an endless drive belt 99; rotating a belt tensioning pulley 100 and two ;
roller pulleys L01 and 1020 By rotating ~he roller pulleys 101 and 102, the roller shafts 81 and 82 are rota~ed w~th the feed rollers 71 and 720 On the other hand, rotation of the drive pulley 98 moves an endless drive belt 103, rotating a belt tensioning pulley 104 and ~wo roller pulleys 105 and 1060 By rotating the roller pulley 106, a roller shaft 107 is rota~ed with the feed rollers 850 Rotation of the roller pulley 105 rotates two engag~ng gear wheels L08 and 109~ By ro~ating the :
gear wheel 109, a roller shaft 110 is rotated with ~he feed rollers 68.
Again looking at Fig~ 5, there is shown the drive mechanism for intermittently oscillating the vacuum cylinder -- :
65 to deliver the forward edges of the ~heets one at a t~me from the origlnating stack to the feed~ng nips 67 ~of the :~
feed rollers 68 and the backup rings 69) as soon as the rear ward edge of a previous sheet departs therefrom. Rotation of the drive shaft 96 rotates two engaging gear whe~ls 111 and 112. Roller bearings 113 support the gear wheel 112 for rota~ion with respect to the drive sha~ 1140 While the gear ~G~77556 wheel 112 is rotating, and a feed command f:rom the logic and . ;
control means of the copier 1 is received by a one revolution clutch 115, the gear wheel rotates the clutch one revolution; ;~
rotating the drive shaft 114 to the same extent. By means of an eccentric 116, one revolution of the drive shaft 114 reciprocates a rod 117 a single time. This causes the vacuum cylinder 65 to rotate back and forth once in the manner des-cribed hereinbefore.
. The present invention has been described ln detail with particular ref'erence to a pref'erred embodiment thereof;
however~ lt should be understood that variations and modi~
cations can be effected within the spirit and scope of' the instant invention.

--211-- ,

Claims (9)

The Embodiments of the Invention in which an Exclusive Property or Privilege is Claimed are defined as follows:

1. A recirculating document feeder for use with copying apparatus and adapted to present at a position for copying original sheets from a stack of such sheets, the respective sheets having a selected side which is to be copied, and the apparatus having a platen at the copying position, said feeder comprising:
means for supporting the stack with the selected side of each sheet facing up and with selected side of the top-most sheet unobstructed for viewing;
means defining a feed path extending first away from and then back to said supporting means, for directing sheets from the bottom of a stack at said supporting means into engagement with the platen and then to the top of the stack, said feed path defining with said supporting means a single closed-loop that inverts the sheet and directs the sheet into engagement with the platen selected side down and then inverts the sheet again and directs the sheet to the top of the stack selected side up;
means for holding a sheet stationary momentarily in engagement with the platen to enable copying of the sheet; and means operatively associated with said supporting means and said path defining means for feeding the respective sheets seriatim along said feed path in a single direction, said feeding means including propelling elements continuously driven for engaging the sheets on the platen and, after copying, for removing the sheets from the platen, said propelling elements slipping on the sheets while the sheets are stationary.

2. A recirculating document feeder adapted to circulate individual document sheets from a stack of such sheets through and exposure station of copying apparatus where the respective sheets are exposed to make copies and back to the stack, the copying apparatus delivering copy sheets image-side-up and with each copy sheet being on top of any previously delivered copy sheets, said feeder comprising:

means for receiving and supporting a stack of document sheets image-side-up, in sequence, with the last sheet of the document on the bottom of the stack and with the stack spaced from the exposure station;

means for circulating the document sheets comprising means (1) for removing the bottom-most sheet from the stack and for presenting the removed sheet to the exposure station image-side-down for copying, and (2) for returning the copied sheet to the top of the stack with the image-side-up; and means for controlling said circulating means so that the document sheets are sequentially circulated to the exposure station one or more times to produce one or more collated copies of the document sheets.

3. A feeder as set forth in Claim 2 wherein the circulating means comprises means defining a closed loop path from the receiving means to the exposure station and back to the receiving means, means located along said path for movement into and out of a position for stopping a document sheet at the exposure station, and at least one continuously rotating feed roller located with respect to the path for continuously driving a document sheet at the exposure station toward said stopping means.

4. A recirculating document feeder adapted to cir-culate each document sheet from a stack of such sheets to a position for copying by copying apparatus, the copying apparatus including means for exposing, one at a time, document sheets located at the copying position to effect the production of one copy each time a document sheet is exposed, and the copying apparatus having means for collecting the copies in a copy stack with the copy images facing up, said feeder comprising:
means defining a feed path extending first away from and then back to said supporting means for guiding sheets sequentially from the bottom of the stack to the copying posi-tion for exposure one at a time and then back to the top of the a sheet over twice as it travels along the path between the bottom of the stack and the top of the stack;
means for locating said feeder on the copying apparatus with exposing means of the apparatus outside of the closed-loop defined by said feed path; and control means for sequentially recirculating the document sheets along the feed path to expose each of such sheets once each time it is at the copying position, thereby to effect production of collated copies of the document.

5. Copier apparatus adapted to feed document sheets, each having a selected side, to an exposure position, and to make copies of the selected sides, the apparatus comprising:
means for supporting a stack of document sheets with the selected side of each sheet facing upwardly before and after exposure;
means defining a feed path for guiding sheets from the bottom of the stack at said supporting means into the exposure position with the selected side facing downwardly and then onto the top of the stack with the selected side facing upwardly, said feed path being substantially in the form of a single loop and including a lower section which defines the exposure position and is located below said supporting means;
means operatively associated with said supporting means for separating sheets one at a time from the bottom of the stack;
means for holding a sheet stationary in said lower section to register such sheet in the exposure position, said holding means being movable to a position to allow a sheet to leave said lower section after exposure of the sheet;
means operatively associated with said defining means and in driving contact with a sheet which is separated from such stack for feeding such sheet in a single direction along said feed path from said separating means and onto the top of such stack in a recirculating manner, said feeding means including propelling means located within said single loop for driving contact with a sheet in said lower section, although slipping on such sheet during the time it is held stationary by said holding means;
drive means for maintaining said feed means continuously in motion while said sheets are in said feed path;
means remote from the path defining means for forming on a copy sheet an image of the selected side of the document sheet;
means for receiving image bearing copy sheets; and means for delivering copy sheets sequentially into said receiving means to form a stack of the copy sheets with such sheets corresponding to the document sheets both in sequence order and in the relative positions of an image on one copy sheet with respect to an image on any other copy sheets.

6. A copier for making one or more copies of each page of a multi-page document, the copier comprising:
an exposure platen against which a selected side of each document page can be placed for copying;
a photoconductive member remote from the exposure platen;
means for projecting an image of a document page at the platen onto the photoconductive member;
means associated with the photoconductive member for forming on a copy sheet an image projected onto the members;
means for receiving and collecting the copy sheets facing up in a copy stack with the first copy made being at the bottom of the stack;
means for receiving the document pages in a stack and for supportin the stack spaced from the exposure platen with the selected side of each document page facing up; and means (1) for successively presenting each document page of the stack to the exposure platen beginning with the bottom-most page and with the selected side engaging the platen for copying, and (2) for returning each document page success-ively to the top of the stack with the selected side facing up;
whereby collated copies of a multi-page document can be obtained by positioning the document pages in a stack in the receiving means with the first page of the document on top of the stack and other pages in serial order therebelow.

7. A copier as set forth in Claim 6 wherein said presenting and returning means comprises means defining a sub-stantially closed-loop path for document pages from the receiv-ing means to the platen and back to the receiving means.

8. A copying machine comprising:
an exposure platen on which a selected side of a document sheet can be positioned to make a copy of the selected side;
a receiving tray spaced from said exposure platen for supporting a stack of document sheets with the selected side of each sheet facing upwardly;
means defining a substantially closed feed path for guiding sheets from the bottom of a stack in said receiving tray to said exposure platen with the selected side facing the platen and then onto the top of such stack with the selected side facing upwardly;
a registration member mounted adjacent said exposure platen for movement between a first position, prior to exposure, wherein the member blocks sheet movement along the path to register sheets at said exposure platen, and a second position, after exposure, wherein the member is positioned out of the path;
at least one continuously rotating feed roller mounted to engage a sheet in the path at said exposure platen for driving the sheet along the path;
means disposed adjacent to said receiving tray for separating sheets one at a time from the bottom of the stack and feeding such separated sheets along path into contact with said feed roller, such roller driving a separated sheet against said member when such member is in its first position to register such sheet at the exposure platen and driving said sheet along said path towards the stack after said member has moved to its second position;
means for exposing a sheet at said platen;
a photoconductive member remote from said platen;

means for projecting an image of a sheet at the platen onto said photoconductive member;
means associated with said photoconductive member for forming on a copy sheet an image of the selected side of a document sheet; and means for delivering the copy sheets in the order copies are made and with the image side of each copy sheet facing in the same direction and with the second of any two adjacent copy sheets being positioned against the image side of the preceding sheet whereby the copy sheets are arranged in the same order as the document sheets.

9. A copier as set forth in Claim 8 further includ-ing means for sensing each time the document sheet, which was upper-most in the stack when first placed in said tray, is fed from the tray to the platen for exposure, and means for de-activating the feeder after the desired number of copies of the entire stack has been made.