CA1144196A - Automatic original document feeder for electrophotographic copier - Google Patents

Abstract

Abstract of the Disclosure A document feeder for advancing original document- to the imaging platen of an electrophotographic copier which is capable of operating in either a semiautomatic or fully auto-matic mode. In the semiautomatic mode, an original to be copied is manually inserted face up into an inlet where it is engaged by the semiautomatic transport assembly, turned around and advanced to a proper position for copying. After exposure the document is again turned around and guided into a receiving tray overlying the platen. In the automatic mode of operation, a second tray normally maintained in a remote or inoperative position is swung down to a position at which its feed end is adjacent the feeder inlet. Docu-ments to be copied are placed face up as a stack in the second tray, and feed rollers carried by the tray are actu-ated to advance documents individually from the top of the stack to the inlet. A friction retarding roller engaging the bottom of the stack and the feed end is positively driven in a reverse direction to prevent the simultaneous feed of more than one document. In an alternative embodiment, the feed roller is disposed below the retarding roller to feed sheets from the bottom of the stack so that the sheets are collected in the stacking tray in their original order.

Description

1144t.9~;

AUTOMATIC ORIGINAL DOCUMENT FEEDER
FOR ELECTROP~TOGRAPHIC COPIER

~acknround of thc Invention Document fccdcrs fnr advancing original document~ to a proper position for copying on the transparent imaqing platen of an electrophotographic copier are well known in the art, being described, for example, in U.S. Patent No.
3,B29,083 issued to.Shiina et al, U.S. Patent No. 3,747,91B
issued to Margulis et al, and U.S. Patent No. 4,129,295 is-sued to Hori et al.
Recently there havc been disclosed automatic document feeders of the "recirculating" type for successively feeding sheets from a stack of originals to the imaging platen of an electrophotographic copier. In one such feeder of this type, disclosed in U.S. Patent No. 4,078,787, issued to Burlew et al, originals are separated from the bottom of a ~tack generally overlying the imaging platen, turned around and advanced to the imaging platcn at which a s~ngle copy 1~
made, and then again turned around and returned to the top of the stack~
While the so-called recirculating document feeders of this type can be uscd to produce collated set~ of cople3 wlth-out any additional sorting stcp, they have several drawback~, ', '~

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~c First, since it is ncccssary to ma~e one full pass in which each original is recirculated for each set of copies des~red, the additional time required to position each document on the imaging platen increases the total copying time. Other pro-blemq arise in the separation of sheets from the stack. In the Burlew et al patent referred to, a vacuum cylinder ~s used as a sheet separator with its attendant bulk, complexity and requirement for the provision of a vacuum pump.
Finally, completely automatic feeders of the recir-culating type have the disadvantage of being overspecial~zed.
That is, the feeders operate most advantageously in the completely automatic mode and are not readily adaptable to operating semiautomatically. The place-marking element re-quired when operating in a recirculating mode also tends to increase the complexity and expense of the overall apparatus.
SummarY of the Invention One of the objects of our invention is to provlde a document feeder for an electrophotographic copier which 19 readily adpated to operate in either a semiautomatic or a fully automatic mode.
Another object of our invention is to provide a docu-ment feeder which is simple and reliable.
Still another object of our invention i9 to provld~ a document fecder wh~ch does not increa~e the overall copyln~
timeO
Other and further objects of our invention w~ll bo apparent from the following descriptionO

1144~96 In general, our invention contemplates a document feeder compri~ing a semiautomatic subassembly, adapted to feed documents inserted in an inlet to the imaging plat-n and then to a receiving tray, together with a fully auto-S matic ~uba~sembly selectably movable between an inoperative position and an operative position for feeding document~ from a stack to the inlet of the semiautomatic assembly. 8y vlrtue of this arrangement it is possible to switch readily between semiautomatic and fully automatic operation, whichever 18 more expedient for a particular task.
In another aspect, our invention contemplates document transport apparatus for use with a copier having an imaglng station in which a feed roller is disposed in engagement with the lowermost sheet of a stack at one end thereof, while a retarding roller is disposed above the feed roller in axial 16 alignment therewith. The feed roller is driven in such a direction as to separate the lowermost sheet from the stack and advance it be~ween the two rollers. The retardinq roller is driven in such a direction as to prevent the passage of more than one sheet at a time ~etween the two roller~. Tho separated sheet is thereafter advanced to the imaglng ~tatlon.
In another aspect, our invention contemplates a docu-ment feeder for an electrophotographic copicr having a generally upwardly facing imaging platen in which document~
from a ~tack placed face down on a support are au~omatlcally advanced off an cnd of thc s~pport to an adjacent inlet whero they are then transported to a facc-down position on th~
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114~196 imaging platen. After exposure, the documents are transported from the imaging platen and are deposited into a stacking tray disposed generally above the platen face down from the top of the tray, thereby preserving the original stacking order.
In yet another aspect, our invention contemplates a feed assembly for advancing documents from a stack in which a feed roller disposed in engagement with the top of the stack at one end thereof is driven to separate the upper sheet there-from, while a retarding roller disposed in engagement with the bottom of the stack at the same end is driven in opposition to the feed roller to inhibit multiple feeding of sheets.
According to the present invention, therefore, there is provided a document transport apparatus for use with a copier having an imaging station. The apparatus includes in combination means forming an inlet for receiving documents, means for transporting documents introduced into the inlet to the imaging station and a document support for receiving a stack of documents. The support has an end and means for automatically advancing documents from the stack off the end of the support and means mounting the support and the - advancing means for movement between a first position with the end adjacent to the inlet and the advancing means operative to advance documents thereto and a second position permitting access to the inlet independently of the document aduancing means.
Brief Description of the Drawings In the accompanying drawings to which reference is made in the instant specification and in which like reference characters are used to indicate like parts in the various views:
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FIGURE 1 iS a fragmentary section of our automatic document feeder in its operative position on an electrophoto-graphic copier.
FIGURE 2 is an enlarged fragmentary section illustrating the drive train of the feeder shown in FIGURE 1.
FIGURE 3 is a schematic diagram of one form of logic circuit for controlling the feeder shown in FIGURE 1.
FIGURE 4 is a section showing the relative position of the rollers-of the drive train of FIGURE 2, taken along the line 4-4 thereof.
FIGURE S is a fragmentary section, taken along line 5-5 of FIGURE 6, of an alternative embodiment of our auto-.

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matic document feeder which feeds sheets from the bottom of the stack.
FIGURE 6 is a fragmentary section of the alternatlYe embodiment shown in FIG~RE 5, taken along line 6-6.
Detailed Description of the Preferred Embodiment Referring now to the drawings, our document feeder, indicated qenerally by tl~e reference character 10, re~t3 upon an electrostatic copier, indicated gencrally by the reference character 12, having a front wall 14, a rear wall 16, and an upper wall 18 supporting a transparent imaging platen 20. ~he feeder frame includes left and right side plates 22 and 23 ex-tending generally along the sides of the copier 12. A pair of left and right rear side plates, one platc 24 of whlch is shown, are secured to the rear portions of the plates 22.
Brackets 26 on the copier 12 carry pi~ot pins 28 extending into rear side plates 24 to permit the entire feeder to be swung away from the imaging platen 20 to permit thick or~-ginal~ such as books to be copied. Suitable limit stops (not shown) define a lower limit position in which the feeder 10 is slightly spaced from the copier 12 as shown.
The transport assembly of the feeder 10, indlcatod generally by the reference character 30, includes a front pulley assembly, indicated generally by the reference charac-ter 32. Pulley assembly 32 comprises a shaft 34 rotatably received by left and right side plates 22 and 23 in front of platen 20 and a plurality of pulleys 36 mounted on tho shaft 34 at spaced locations therealong. A rear pulley as~embly, ., - , _5_ .

li,,~lg6 ' indicatcd generally by the reference character 38, include~ a shaft 40 rotatably rcceived by left and right side plate- 22 and 23 behind the imaging platcn 20 and a plurality o~ pul-ley3 42 mounted at spaced locations on the shaft 40. A motor 44, ~hown schematically in FIGURE 3, is intermittently actu-ated in a manner more fully described hereinbelow to drive shaft 34 in a counterclockwise direction as viewed in FIGURE
1. .
A plurality of frictional transport belts 46 ~up-ported between rcspcctive pulleys of the front and rear pul-ley assemblies 32 and 38 form a conveyor loop. A plurality of flanged tension pulleys 50 provide belts 46 with a suit-able amount of tension. Tension pulleys 50 are rotatably supported at ends of resilient metal strips 48, the other ends of which are secured by clamps 52 to a transversely dis-posed supporting rod 56. A rounded guide bar 54 extending transversely of the feeder at a location between the front edge of the platen 20 and the pulley assembly 32 diverts portions of the belts 46 slightly below the level of the platen 20.
An upper guide 122 and a lower guide 124 formed from the upwardly inclincd rear edge of a platform 126 form a document-receiving inlct, indicated generally as A, at the top of the rear pulley assembly 38. If the automatic feeder assembly is not used, documents may be fed manually to th-transport assembly 30 by placing them one at a time face up on the platform 126 and moving them rearwardly into the inlet A.
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An automatic original removal and dclivery a~sembly, indicated generally by the reference numeral 5a, doliYers originals individually to the transport belts 46. Assembly 58 comprises a support 64 extending between left and right ~lde plates 60 and 62 and inclined downwardly toward the upper end of rear pulley assembly 38 from the direction of the front pulley assembly 30. A cross bar 66 extends between the upper portions of side platcs to provide additional structural ri-gidity. Pivots 72 and 74 carried by respective left and right L-shaped brackets 6~ and 70 support side plates 60 and 62 for pivotal movement from a normal or operative position shown in solid lines in FIGURE 1 to a raised or inoperative position fragmentarily shown in dot-dash lines in the same figure.
Brackets 68 and 70 are mounted on respective side platet 22 of the feeder 10 along the upper edges thereof by means of outwardly extending lower flanges 80. A respective outwardly extending portion 78 at the upper longitudinal edge of each of bracket~ 6B and 70 carries a rubber foot 82. Feet 82 abut outwardly extending stops 76 on the side plates 68 and 70 to define a lower or operative position of the pivoting portion of assembly 58. Side plates 60 a,nd 62 are also formed wlth outwardly extending stops 84 near the pivots 72 and 74 whlch abut the upwardly extending portions of brackets 68 and 70 when the as~embly portion is pivoted to define an upper ll~lt position.
A ~haft 92 carried by rcspective bearings 94 in ~lde plate~ 60 and 62 supports a pair of axially spaced frlctlon . .. ~7~

441~6 ~

feed rollers 86 and 8~ just above the upper surface of the support 64. Prefcrably, feed roller-~ 86,and 88 have re-latively soft working surfaces and are serrated with the teeth inclined toward tho direction of feed as shown ln ~IGURE 1 to provide a more positive gripping action. A one-way clutch 90 mounts rollers 86 and 88 on shaft 92 to permlt freewheeling clockwise movement as viewed in FIGURE 1. A
second shaft 106 mounted in bearings 107 in side plates 60 and 62 below the feed rollers 86 and 8~ carries a relatfvely bard lower retarding roller 108, Lower roller 108, which iJ
positioned exiall~ between feed rollers 86 and 88, extends above the level of support 64 to form a n~rrow gap with a soft relatively smooth restriction roller 110 carried by upper shaft 92. As shown in FIGURE 4, roller 110 has a some-what smaller radius than that of rollers 86 and 88 to augment the gripping action of the latter rollers and to ~scallopU
the sheet being advanced to give it longitudinal rigldity.
We space roller 110 at such a distance from retarding roller 108 as to permit the passage of only a single sheet there-between.
A drive belt 98 carried by lower shaft 106 and ~y ~
pulley 96 on upper shaft 92 also extcnds around a pulley 100 carried by the shaft 102 of a motor 104 mounted outboard of the left side plate 60. Motor 104 is intermittently ener-gized in such a direction as to rotate shafts 92 and 106 ln a clockwise direction as seen in FIGURE 1 to move the uppor rollers 86, 88 ~n an advancing direction and the lower rollor 108 ~n a retarding direction.
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, Sheets to be fed are placed face up on the support 64 above the level of rollers 86 and 8B between the right ride - plate 62 and a longitudinally extending paper edge guide 112.
One or more pins 113 extending through a transverse slot 116 in base 64 and through a 910t 115 in a plate 114 carried by the underside of base 64 secure a plate 118 to guide 112.
This arrangement pcrmits adjustment of the lateral position of the edge guide 112. Screws 120 carried by plate 118 may be tightened to engage plate 114 to secure the edge guide 112 in position.
When an original is to be copied, motor 104 is energized to drive feed rollers 86 and 88 to separate the lowermost original from the stack S and to advance it through the inlet A. The original is then directed around the rear pulley assembly 3fl along a transport path defined by a cylindrical guide 128.
A plurality of fingers 130 are selectively moved - through suitable openings in cylindrical guide 12~ and across - the transport path defined by the guide 128 to prevent the original from moving past a predetermined point alo~g it~
transport path. Fingers 130 are preferably stamped or are otherwisc formed from a single sheet 132 of metal or other material, securcd to a support 134 carried by a shaft 136.
A plurality of drivc rollers 137 mounted on the ~econd pullcy as~ombly sha~t ~0 at spaccd locations -from it~ r~ght end and having a diameter greater than that of pulleys 42 by twice the thickness of bclts 46 assist in driving an .

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original around the transport path defined by cylindrical guide 123. Rollers 137 preferably comprise a suitable low-friction material. Rollcrs 137 cooperate with a plurality of pressure rollers 138 preferably having a somewhat ~maller diameter and provided with rubber tires 140 to provide.high-friction working surfaces. A shaft 142 supports pressure rollers 138 for commDn rotation at spaced locations corre~-ponding to the locations of rollers 137. A shaft 144 ro-tatably supported by side plates 22 carries a central arm 146 for rotation therewith. Shaft 144 and arm 146 sUppOrt the pressure roller assembly for swinging movement toward and away from the drive rollers 137. Shafts 142 and 144 and arm 146 are disposed in such a manner as to permit pressure rollers 138 to engage drive roller~ 137 along a line between the inlet A and the stop fingcrs 130. Cy-lindrical guide 128 is provided with suitable slots to permit engagement of the pairs of rollers 137 and 138.
The pivot shaft 144 carries a cranX plate 148 provided with a crank pin 150. The stop finger shaft 136 carries an arm 154 having a slot 152 formed in its end for receivlng pin 150. Pivot arm shaft 144 is thus coupled to stDp finger shaft 136 in such a manner that movement of the pres~ure rollers 138 into engagement with the drive roller~ 137 is accompanied by a movemcnt of the stop fingers 130 away from the transport path defincd by the cylindrical guide 128. Tha armature of a soleooid 156 is connected by a suitablc linkage to crank plate 148 to rotate shaft 144 in a clockwifl-direction (as seen in FIGURE 1) against thc action of a --10-- .

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~pring 158 when the solenoid is cnergized. Normally, the spring 158 maintains the above-described inlet assembly ln a disengaged position, shown in FIGURE 1, in which the pressure rollers 138 are disengaged from the driver roller~
137 and originals are prevented from moving further along the transport path by fingers 130. When the inlet assembly is in such a disengaged position, motor 10~ may be energized to advance an original through the inlet A.
The feeder assembly 58 continues to advance~the original along the transport path until its leading edge i9 beyond the pressure rollers 138. At this point, motor 104 is di~abled and motor 44 is actuated to drive the transport belt~ 46. Simultaneously with the actuation of motor 44, solenoid 156 is actuated to pull the lower end of the crank plate 148 toward the rear of the feeder, thereby moving f1ngers 130 away from the transport path and moving pressure rollers 138 into engagement with drive rollers 137 to propel the sheet along the transport path. ~he freewheeling con-struction of feeder assembly feed rollers 86 and 88 readily permits the transport asscmbly 30 to pull the trail~ng portion of the fed original from the feeder assembly 58~
Preferably, to prevent possible jamming, the linear speed of the transport belts 46 which is about 1 meter per second should be somewhat greater than that of the feed rollers 86 and 88.
Upon emerging from thc lower cnd of the cylindrical guide 128, the origin~l follow~ a path defined from below by the imaging platen 20 and rear edge platc 160 and from .

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above by a guide plate 162 mounted between side plate~ 22 ~n parallel closely spaced relationship with the imaging platen 20. Guide plate 162 oxtends over the imaging platen 20 and edge plate 160 and has a plurality of finqers 164 extending generally upwardly and rearwardly between drive roller~ 137 and pulleys 42 to ensure that the original is fed under the guide plate 162.
~espective front and rear pressure roller~ 166 and 16B
disposed above the inner belts 46 maintain the original in a close contacting relationship with the imaging platen 20 a~
the original advances across the platen's upper surface. We rotatably mount each of the rollers 166 and 16 in a roller support 170 carried by a rod 172 extending from a block 174.
A shaft 178 transversely arranged between side plates 22 rotatably supports the front roller blocks, while rod 56 supports the rear roller blocks. Rollers 166 and 168 are thus biased against thc belts 46 by the weight of the roller supports 170. Rods 172 are loosely retained by screws 176 within blocks 174 to help equalize the force on adjacent belts.
A housing 180 in front of platen 20 receive~ a multi-fingered gate 182 which may be moved into the transport path followed by the original to stop it for copying. A soleno~d 184 shown in FIGURE 3 couplcd to the gate 218 i9 actuated to move the gate 182 from a normal blocking po~ition into a nonblocking or retracted position.

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The original is moved along the platen 20 by the transport belts 46 until the leading edge of the orig~n~l abuts the gate 1~2 and further forward movement i9 prevented.
The transport belts 46 then slip relative to the origlnal while at the same timc providing a gentle force which aligns the leading edge of the original against the fingers if ~t has become skewed.
With the original in place, the optical scanning system ~not shown) of the copier 12 is actuated to produce the desired num~er of copie~. When the exposure portion of the la~t copying cycle is complete, the solenoid 184 i~
actuated to retract the gate fingers from the transport path to allow the original to be advanced to the tray 206. A
guide 186 having finqers 188 extending rearwardly and up-lS wardly between adjacent belts 46 ensures that the oriqinal i9 separated from the belts and is not carried around the pulley assembly 32. The fingers 188 are recessed in notche~
(not shown) provided on the underside of guide bar 54. The original moves along an upwardly curved guide 190 into the tray 206. For this purpose, pulley assembly 32 is arranged so that tlle trained portions o~ the belts 46 are tangent to the surface of the guide 190. A plurality of drive rollers 192 are disposed at a tangent to the inner surface at a location spaced downstrcam from the belts 46. ~elts 46 and rollers 192 engage fir~t and second pluralities of idler rol-ler~ 194 and 196, respectively, mounted on the other lde of the guide 190. Guide member 190 i8 provided with slot- at ', ' ~

suitable locations to permit rollers 190 and 196 to contact belts 46 and rollers 192~ respectively. Rollers 192 ar-mounted on a shaft 198 rotatably received by side panelJ 22.
Documcnt~ exiting ~rom the upper end of guide 190 at an outlet B enter a collection tray 206 disposed between the platform 126 and guide 162. Tray 206 is formed with a de-pression 20B at its front end to facilitatc the removal of documents therefrom and has a front wall 204 the upper end of which iq bent forward to shield the rotating parts of the transport assembly 30. A transparent cover 210 attached to the front edge of platform 126 by means of hinges 292 serve3 to direct exiting documents downwardly into the tray 206.
Longitudinally extending ribs 214 on the underside of cover prevent the generation of any undesirable electrostatic change on the stacking documents.
~he combined operation of the feeder assembly 58 and the transport assembly 30 will now be described in some de-tail. Before the copier 12 is actuated, fecder assembly motor 104 is energizcd to advance the lowermost original from the stack S through the inlet A past the pressure rol-lers 13~. At this point, fceder aqsembly motor 104 i~ de-energized, while transport assembly motor 44 and solenold 156 are energized to move thc prcssure rollers 138 agalnst drive rollers 137 to move the original along the transport path onto the imaging platen 20. One-way clutch 90 permlts roliers 86 and 8B to be overdriven by rollers 138 and 137.
Transport assembly motor 44 remains cnorgized until a Jhort ~14A196 period after the leading edge of the original abutJ th~
fingers of the exit gate 182 ~o realign the original lf it ha~ become skewed.
With the original in place on the platen 20, tho flcanning system of the copier 12 is actuated to maXe tha desired number of copie~. At the end of the last exposure, solenoid 1~4 i9 actuated to retract the cxit gate 182 and transpDrt assembly motor 44 is reactuated to move the orl-ginal along guide 190 into the tray 206. Simultaneously with the advance of the first original, feeder assembly motor 104 i9 reactuated to advance a second original through inlet A
to feed it to rollers 137 and 138. The operation of a~-semblies 58 and 30 is now repeated in cyclical fashion, with successive originals being advanced to and removed from the imaging platen 20 between the exposure portions of succes~$ve copying cycles. Thc opcration is continued until all of the originals have been advanced past the imaging platen 20.
Referring now to FIGURE 3, we show an exemplary control circuit for our automatic feeder. Before maXing any copies, the opcrator activates a suitable selector cir-cuit 216 to load a signal representing the nu~ber of orl-ginal~ into a digital counter 218. Counter 21a, which count~ down one in response to a positive-going oignal ~up-plied to a clock pulse (CP) input, provide~ an AND gate 220 with a 1 or "high" logic signal whenever the count is greator . .

than zero. Aftcr placing a stack of originals face up to thQ
support 64, the operator momentarily closes a "print" ~witch 222 to initiate the feeding cycle. Closure of switch 222 supplies a "high" logic signal from a line 224 to one input of an OR gate 226 to provide a 1 or "high" logic signal to the other input of AND gate 220. AND gate 220 then sets an RS-type flip-flop 228 to logic level 1 to provide a "high"
output to a noninverting driver 230. Driver 230 drives a coil of a single-pole normally open relay 232 to connect the feeder assembly motor 104 between AC supply lines 234 and 236.
In the manner described previously, motor 104 drives feed rollers 86 and 88 to advance the uppermost original in the stack S through the inlet A until the leading edge of the original actuates a microswitch Sl disposed just beyond the -pressure rollers 13fl. Closure of switch Sl applies a posi-tive voltage from line 224 to one input of an OR gate 23a to provide a hiqh, or positive, input to a noninverting driver 240. Driver 240 drives the coil of a double-pole normally open relay 242 which controls both the transport assembly motor 44 and the solenoid 156. As a result, the belts 46 of the ~ransport as~embly are driven while, simultaneously, fingcrs 130 are retracted and pressure rol-ler~ 138 are moved into engagement with the original to mo~e it along the transport path. A delay circuit 244 coupled between switch Sl and the reset ~R) input of fl~p-flop 22~
delays the leading cdge of the switch signal 90 that, a s~ort ' :

` 1144196 time interval after the witch Sl i9 closed~ flip-1Op 228 is reset to provide a 0 or "low" logic output, di~abling feeder motor 104.
As the leading edge of the original moves beyond roller~ 138, it engages a microswitch S2 disposed near the lower end of the guide 128. ~ a result, the potential from line 224 is appli.ed through switch 52 to a second input to OR gate 238 so that the motor 44 and the solenoid 156 remain energized after the trailing edge of the original has moved past switch Sl. Switch S2 is also coupled to the input of a delay circuit 246 to provide an output with a delayed trail-ing edge to a third input to OR gate 238. OR gate 238 thus remains at logic level 1 for a short time after the trailing edge of the original has cleared switch S2 to ensure that the belts 46 move the leading edge of the original against the fingers of the cxit gate 182. After a short time interval, delay circuit 246 provides a "0" output to OR gate 238, dis-abling the transport assembly motor 44 and the solenoid 156.
The output of OR gate 238 is also applied through a logic inverter 248 to a one-shot multivibrator 250. When motor 44 and ~olenoid 156 arc di~abled, one-shot multivibrator 250 provides a pulse to thc scanning control circuit 252 of tho .
copier 12, initiating the copying operation. Multivibrator 250 also provides a pulse to counter 218 through delay cir-cuit 272, causing it to count down one, After the first.or any succeeding original except the last has been copied one or more time~, the original is ad^
vanced to the stac~ing tray 206 while a new orlginal i~ ad-'' ' ' - ~ 4~6 .

vanced from the top of the stacX S ~o the imaging platen 20.
To this end, momentary actuation of a line 254 by copler logic 252 at the end of the copying c.ycle provides pulse in put~ to OR gates 226 and 256. As a result, flip-flop 228 again set to energize the feeder motor 104 to advance a ~econd original from the stack S. At the same time, OR gate 256 drives the input of a driver 258 coupled to a normally open relay 260. The contacts of relay 260 are coupled to the exit gate solenoid 184. OR gate 256 also drive~ one in-put of an OR gate 262 directly and another input through a further delay circuit 264. Gate 262 drives a relay 266, con-trolling transport assembly motor 44, through a driver 268.
Thus, aftcr an original has been copied, the exit gate 182 is retracted to permit further movement of that original along the transport path while motor 44 is energized to drive the transport belts 46. Line 254 continues to supply the pul~e to OR gate 256 for a sufficient period of time to al-low the leading edge of the fir~t original to trip an exit switch S3 disposcd just beyond the exit gate 182. When the first original trips switch S3, the potential from line 224 i8 applied through that switch to a second input at OR gato 256 so that the mo~or 44 and the solenoid 184 remain ener-~: gized.
Switch S3 is coupled through a delay circuit 270 to a third input of OR gate 256. ~ircuit 270 delays the nega-.
tive-going edge of its input .~o ~hat, a short period after the trailing edge of thc first original clears switch S3, the output of delay circuit 270 changes to zero to producu a zoro .
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output from OR gate 256. As a result, solenoid 184 is dls-abled. Motor 44 rcmains energized, however~ since by thls time the second original has advanced far enough to trip microswitch 51 in the manner described before. Delay clrcuit 270 has a time constant such that, by the time its output changes to zero, the trailing edge of the firs~ original haJ
cleared the exit gate 182, but the leading edge of the se-cond original has not yet reached that point. Motor 44 thu3 advances the second original into place for copying wh~le at the fiame time advancing the first original to the stacking tray.
The process as described above is repeated until all of the originals have been copied. When the last original is fed to the imaging platen to make one or more copies, counter 218 counts to zero and disables AND gate 220 so that the feed motor 104 remains unactuated by the pulse on line 254 when ~- the last original is advanced to the stack tray. In response to that pulse, however, transport motor 44 remains enerqlzed for a sufficient period of time, as determined by delay cir-cuits 270 and 264, to advancc the last original to the tray 206. One-shot multivibrator 250 does not produce a pulse at this time, though, since intake switches Sl and S2 are not actuated. ~, While they do not as such form a part of the present invention, further details of the con~truction and operatlon of the transport assembly 30 and associated control circult may be found in copcnding application of To Hori, Serlal ~o.

, 8a4,999, filed March 9, 1978, owned by the assignee hereln.
Referring now to FIGURES S and 6, we show a preferred form of our invention in which the fceder rolles i9 dispo~ed below the retarding roller to feed sheets from the bottom of the stack S and thus allow the ~heets ~o be collated in the tray 206 in their original stacking order. Morc particularly, referring now to the drawings, shaft 106 supports a high-friction rubber feed roller 2?2 extending through an opening 282 in base 64. Upper shaft 92 supports a lower-friction rubber retarding roller 276 of about the same hardnes~ as roller 272. Rollers Z72 and 276 are in axial registry with each other and are radially spaced from each other by such a distance as to permit the passage of only one sheet 284 therebetween.
Feed roller 272 is driven in a counterclockwiJe direction as viewod in FIGURE 6 to drive the lowermost sheet 284 through the nip formed by the rollers, while retarding roller 276 is driven in the same rotary direction to oppose the passage of the other sheets in the 3tack S. ~o rotate the rollers 272 and 276 in this manner, the same power train as before i9 used, the direction of drive of motor 104 simply being reversod. A one-way clutch 274 couples feed roller 272 to shaft 106 to permit freewheelinq counterc~oc~-wise motion, allowing the roller 272 to be overdriven when the ~heet 284 is taken up by the rear pulley as3embly 38.
A pair of low-friction motal or plastic scalloplng wheel~ or discs ~78 and 280 mounted outboard of roller 276 .

~441~6 on shaft g2 and having a slightly greater diameter than that of roller 276 "scallop" the sheet 284 slightly as shown n FIGURE 5 to prevent the leading cdge of shect 2B4 from curl-ing over as it clears rollers 272 and 276 and to increa-e the effective frictional force exerted by roller 272. Pre-ferably, scalloping wheel~ 278 and 260 have ro~nded edges as shown in FIGURE 5 and are adjustable exially to accom-modate sheets 284 of various weights or stiffnesses.
It will be seen that we have accomplished the objects lQ of our invention. Our document feeder is capable of operat-ing in either a semiautomatic or a fully automatic mode, while at the same time being simple and reliable.
It will be understood that certain features and 9ub-combinations are of utility and may be employed without reference to other features and subcombinations. ~his i~
contemplated by and is within the scope of our claims.
It is further obvious that various changes may be made in details within the scope of our claims without departing - from the spirit of our invention, It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.
Having thus described our invention, what we cla~m is~

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Document transport apparatus for use with a copier having an imaging station, said apparatus including in combination means forming an inlet for receiving documents, means for transporting documents introduced into said inlet to said imaging station, a document support for receiving a stack of documents, said support having an end, means for automatically advancing documents from said stack off said end of said support, and means mounting said support and said advancing means for movement between a first position with said end adjacent to said inlet and said advancing means operative to advance documents thereto and a second position permitting access to said inlet independently of said document advancing means.

2. Document transport apparatus for use with a copier having an exposure platen, said apparatus including in combination means including a generally horizontal lower guide surface forming an inlet for receiving sheet documents, means including a pair of opposing feed members for gripping documents introduced into said inlet and transporting said documents to said exposure platen, a document support for receiving a stack of documents, said support having an end, means for automatically advancing documents from said stack off said end of said support, and means mounting said support and said advancing means for movement about a pivot axis adjacent said inlet between a lowered position with said end adjacent to said inlet and said support sloping upwardly therefrom and a raised position permitting access to said inlet independently of said document advancing means, said advancing means comprising a feed roller, means for disposing said feed roller in engagement with the uppermost sheet in said stack at said end, a retarding roller, means for disposing said retarding roller below said feed roller, means for driving said feed roller in such a direction as to separate the upper sheet from said stack and advance it between said rollers, and means for driving said retarding roller to prevent the passage of more than one sheet at a time between said rollers, said advancing means being operative in said lowered position to advance documents from said support to said inlet.

3. Document transport apparatus for use with a copier having an exposure platen, said apparatus including in combination means including a generally horizontal lower guide surface forming an inlet for receiving sheet documents, means including a pair of opposing feed members for gripping documents introduced into said inlet and transporting said documents to said exposure platen, a document support for receiving a stack of documents, said support having an end, means for automatically advancing documents from said stack off said end of said support, said advancing means being disabled after moving a document a predetermined distance from said stack, and means mounting said support and said advancing means about a pivot axis adjacent said inlet for movement between a lowered position with said end adjacent to said inlet and said support sloping upwardly therefrom and a raised position permitting access to said inlet independently of said document advancing means, said advancing means being operative in said lowered position to advance documents from said support to said inlet.

4. Document transport apparatus for use with a copier having an exposure platen, said apparatus including in combination means including a generally horizontal lower guide surface forming an inlet for receiving sheet documents, means including a pair of opposing feed members for gripping documents introduced into said inlet and transporting said documents at a certain linear speed to said exposure platen, a document support for receiving a stack of documents, said support having an end, means for automatically advancing documents from said stack at a slightly slower speed off said end of said support, said advancing means adapted to be overdriven by said transporting means, and means mounting said support and said advancing means for movement about a pivot axis adjacent said inlet between a lowered position with said end adjacent to said inlet and said support sloping upwardly therefrom and a raised position permitting access to said inlet independently of said document advancing means, said advancing means being operative in said lowered position to advance documents from said support to said inlet.

5. Document transport apparatus for use with a copier having an exposure platen, said apparatus including in combination means including a generally horizontal lower guide surface forming an inlet for receiving sheet documents, means including a pair of opposing feed members for gripping documents introduced into said inlet and transporting said documents to said exposure platen, a document support for for receiving a stack of documents, said support having an end, means for automatically advancing documents from said stack off said end of said support, and means mounting said support and said advancing means for movement about a pivot axis adjacent said inlet between a lowered position with said end adjacent to said inlet and said support sloping upwardly therefrom and a raised position permitting access to said inlet independently of said document advancing means, said advancing means being operative in said lowered position to advance documents from said support to said inlet.

6. A document feeder for an electrophotographic copier having an upwardly facing exposure platen including in combination means including a generally horizontal lower guide surface forming an inlet for receiving sheet documents, means for supporting a first stack of documents with an edge.
adjacent said inlet and with one side face up, means for automatically advancing a document from the bottom of said stack to said inlet, means including a pair of opposing feed members for gripping said advanced document and transporting said document to said platen with said side face down, means disposed between said platen and said first supporting means for supporting a second stack of documents, said first supporting means supporting said first stack in an inclined position relative to said second stack, means for transporting said document from said platen to the top of said second stack with said side face up, and means mounting said first supporting means and said advancing means for movement about a pivot axis adjacent said inlet between a lowered position with said edge of said stack adjacent said inlet and said support sloping upwardly therefrom and a raised position permitting access to said inlet independently of said advancing means, said advancing means being operative in said lowered position to advance documents from said support to said inlet.