CA1123023A - Pickoff device for copying machine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A pickoff device for a copying machine of the image transfer type in which the leading edge of the copy sheet to which the image has been transferred is guided from the surface on which the image was formed and developed into a delivery opening through which copies are to be delivered to the user. First pickoff means are positioned adjacent the opening to act on a normally conveyed sheet to remove the sheet from the image transfer surface and to deliver it to the conveyor which returns it to the user.
An auxiliary device positioned remote from the path of sheet travel intercepts any sheet which has missed the first pickoff means and guides the intercepted sheet to the conveyor so that the intercepted sheet may be returned to the user.

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Description

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This is a division of Canadian application Serial No. 311,447, filed September 18, 1978.

Background of the Invention _ There are known in the prior art plain paper electrostatic copying machines in which a drum carries a surface coating of photoconductive material, such for example as selenium. In operation o~ such a machine the surface of the drum is moved successively past the charging station at which a corona applies a uniform electrostatic charge over the surface of the drum and then to an exposure station at which the char~ed surface i5 exposed to an image -~
of the original to be copied. At this station, the surface of the drum over relatively light areas of t~e image to be copied loses its charge while retaining its charge in relatively darker areas of the original, thus to produce a latent electrostatic image of the original to be copiedO
Following the exposure station, the surface is carried through a developer station at which the latent image is subjected to the action of the developer including toner particles which adhere to the charged areas of the image, thus to develop the image. As the surface carrying the developed image leaves the developer station~ it moves past a point at which a length of copy material, such as ordinary

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3~ 3 paper to which the image is to be transferred is fed to the drum so as to be carried along with the drum beneath a transfer corona. This transfer corona causes the particles of toner to migrate from the surface of the photoconductor to the surface of the copy sheet.
After the imac~e has thus been transferred to the length of copy material, it is necessary to remove the she~t from the surface of the photoconductor which may, for example t be on a drum. In one particular arrangement employed to pickoff a copy sheet carrying a developed image in a machine of the type described above, a stationary flexible band conforming to the configuration of the drum over a portion of the circumference thereof from the location at which copy material is fed to the drum to a location beyond the transfer corona is mounted at the edge of the drum, so that a narrow strip of copy material extending along a side thereof moves over the stationary flexible band *~ as the length of copy material moves under the transfer corona. At the point at which the copy material is to be removed from the surface of the drum, a struck up portion of the flexible strip moves a leading corner of the length of copy material away from the drum and into the nip between a turn roll and a rubber belt, a portion of the length of bm:

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~3~3 which extends around and into contact with the surface of the turn roll. The turn roll is driven in cooperation with the belt to carry the developed sheet away from the photoconductive drum toward conveyor rollers which deliver the sheet to the user of the machine. This pickoff arrangemenk is illustrated in and is more fully described in Ariyama U.S. Patent 3,936,045, for "Sheet Stripping Device for Copying Apparatus".
After the photoconductive surface leaves the pickoff station described hereinabove, it next moves through a cleaning station at which a sponge roller in engagement with the surface of the drum is driven in such a direction that the engaging surface portions of the roller and the drum move in opposite directions. This sponge roller normally is wet with developer to facilitate the cleaning action and to prevent scratching of the drum surface by toner particles which remain on the roller when the developer dries.
While the machine described above~functions satisfactorily in most instances, it incroporates a number of serious disadvantages. First, it will readily be apparent from the description of the pickoff system described hereinabove, that the Gopy sheet can have no image transferred thereto over the space along the edge thereof which rides bm: , 3~3~23 over the flexible band extending through the transfer station. Thus, where the original carries information or printing in this area, it will not appear on the copy.
Attempts to obviate this problem by minor modifications for direc-ting the corner of the sheet into the nip between the turn roller and the belt withou-t the use of a strip extending through the transfer station have not proved successful since any developed image in the strip which formerly was blank become smeared or dirtied. Another defect of the machine described hereinabove arises in connection with accidental double ~eeding of copy sheets from the supply to the drum. The first of the two sheets will be picked off by the pickoff device but often times the second sheet misses the pickoff. ~hen this occurs the sheet may continue to travel around with the drum and become wrapped around the cleaning roller and ultimately soaked with developer, so as to assume a dark appearance so as not to be readily discernible. In such an instance upon continued use of the machine, the sheet wrapped around the cleaning roller scratches the surface of the photoconductor and ultimately may require replacemen-t of the photoconductive drum. This member iso~e of the more èxpensive components of the machine.

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The problems of the prior ar-t are overcome by the invention according to the parent application which provides, in a copying machine oE the image transfer type in which an image developed on a surface is transferred to a sheet of copy material which moves with the surface through a transfer station to a pickofE station, pickoff apparatus including a first clutch element, means for driving the Eirst clutch element, a second clutch element, means mounting the second clutch element for movement rela-tive to the first clutch element with a narrow space betweenthe elements, an opening leading into the narrow space, means positionlng the clutch elements with the opening at a location adjacent to the surface, mea.ns for directing a portion of a copy sheet from the moving surface into the space between the elements, the relationship be-tween the thickness of the sheet and the space between the elements being such that entry of the sheet into the space clutches : the elements to each other for movement as a unit, and means responsive to a predetermined movement of the members as a unit for releasing the portion of a copy sheet.
On the other hand the invention according to the present application provides, a copying machine of the image transfer type in which an image developed on a surface is transferred to a sheet of copy material which moves with the surface through a -transfer station to a pickoff station with a leading corner of the sheet normally moving along a path, apparatus including a housing for the copying machine having a delivery opening through which copies are to be delivered to the user of the machine, conveyor means for receiving a sheet and delivering it through the opening, first pickoff means positioned adjacent to the path for acting on a normally conveyed sheet over a leading limited jb/,~ - 6 -region adjacent to the pa-th to remove the normally conve~ed sheet from the surface and to deliver it to the conveyor means, and auxiliary means located relatively remote from the path for intercepting a copy sheet which misses the pickoff means and for guiding the intercepted sheet to the conveyor means to cause the conveyor means to deliver the intercepted sheet -to the user.
Furthermore, the present inven-tion may be consid-ered to provide a copying machine of the image transfer type in which an image developed on a surface is transferred to a sheet of copy material which is fed to the surface from a supply of sheets and which moves with the surface through a transfer station to a pickoff station apparatus including a housing for the copying machine having a deliver~ opening through which copies are to be delivered to the user of the machine, conveyor means for receiving a sheet and delivering it through the delivery opening, first mechanical pickoff means comprising a mouth forming a narrow space approximately equal to the thickness of a sheet of copy material, adapted to receive the leading edge of a sheet, the first pickoff means adapted to be actuated to carry a sheet received in the mouth to the conveyor means, and auxiliary means adapted to direct the second sheet of a pair of double fed sheets from the supply, which second sheet misses the mouth, to the conveyor means to cause the second sheet to be delivered to the user without interruption of the operation of the machine.

jb/~ 6a -3~23 the instant specification and ~Ihich are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts of the various views:
FIGURE 1 ls a simplified schematic view of the drive system of an elec-trostatic copying machine incorporating my pickoff device with parts of the machine removed, FIGUR~ 2 is a diagrammatic view of the copy paper handling sys-tem of the electrostatic copier illustrated in FIGURE 1.
FIGURE 3 is a fragmentary sectional view of the copying machine illustrated in FIGURES 1 and 2 and showing the details of my pickoff device, FIGURE 4 is a fragmentary view with parts in section illustrating my pickoff device for copying machines.
FIGURE 5 is a fragmen-tary elevation of a portion of my pickoff device for copying machines.
FIGURE 6 is a fragmentary sectional view of one form of my pickoff device for copying machines.
FIGURE 7 is a view similar to FIGURE 6 illustrating an alternate form of my pickoff device for copying machines.
FIGURE 8 is a view similar to FIGURE 6 illustrating a further form of my pickoff device for copying machines.
FIGURE 9 is a fragmentary side elevation illus-trating my means for returning a double fed copy sheet to the user of the machine.

Description of the Preferred Embodiment Referring now to FIGURES 1 and 2Of the drawings, a machine indicated generally by the reference character 10 with which my pickoff device is used includes a cabinet 12, bm J c ~3~

the top of which is provided with a transparent platen 14, normally covered by a cover 15 hinged to the cabinet. The cover can be moved away from the platen to permit an original to be placed face down to the pla-ten. A drum 16 carrying a suitable photoconductor on the surface thereof is rotatably supported for movement in the cabinet 10 by any suitable means known to the art. In the schematic view in FIGURE 1, for purposes of simplicity, I have illustrated gears in broken lines and have indicated sprocket wheels in full lines. A gear 18 which rotates with the drum 16 is adapted to be driven to rotate the drum in the direction of the arrow A in EIGURE 1. Machine 10 includes a prime mover 20, the output shaft to which carries a sprocket wheel 22 adapted to drive a pitch chain 24 to drive a sprocket wheel 26. Chain 24 moves in the direction of the arrow adjacent to the chain so that a gear 2~ mounted on the shaft of ~ sprocket wheel 26 for rotation therewith drives gear 18 to rotate the drum 16 in the direction of the arrow A.
Further, as is known in the ar-t, as the drum 16 rotates in the direction of the arrow A, its surface moves successively past a corona 30, which is activated to produce a uniform electrostatic charge on the surface of the drum. After leaving the corona 3Q, the surface passes by an exposure station indicated by the arrow 32 at which a moving optical sys-tem scans the original which has been placed face down on platen 14 so as to translate a line image of the original to the surface of the moving drum 16. Since the details of the optical system, per se, form no part of our invention, they have not been shown in the drawings.

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After leaving the exposure station 32, the surface of the drum moves through a developer unit 34 at which the latent electrostatic image thereon is subjected to the action of a liquid developer containing particles of toner which adhere to those areas of -the drum surface which have retained their charge after exposure to the image.
As the developed latent image moves further in the direction of the arrow A, a sheet of plain paper is fed to the drum at a station indicated generally by the reference character 36.
The paper moves with the drum past a transfer corona 38 which is energized to cause the developed image to migrate from the surface of the drum to the underside of the paper.
After transfer has thus been effected, the sheet carrying the developed and transferred ima~e is to be carried away from the drum at a pickoff station indicated generally by the reference character 40.
A gear 42 which meshes with the drum gear 18 provides the input to the copy pickoff and delivery system.
Gear 42 is on a shaft which is common with a sprocket wheel 44 so that gear 42 and sprocket wheel 44 rotate around an axis "b" which is the axis of the take-off roll to be described more fully hereinbelow. Sprocket wheel 44 drives pitch chain 46 in the direction of the arrow adjacent to `
the chain in FIGURE 1. Chain 46 in turn drives a sprocket wheel 48, the shaft of which also carries a gear 50 which meshes with a gea~ 52 to drive gear 52 in a counterclockwise direction around the a~is "a" o~ the cleaner roll to be describes in detail hereinbelow.
Chain 46 also enyages a tensioning sprocket wheel 54 and a sprocket wheel 56 mounted for rotation around the bm~

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3~3~3 axis "c" of the lower of a pair of take-off rolls to be described hereinbelow. A hold-down roller sprocke-t wheel 58 is engaged by chain 46 so as to be driven in counter-clockwise direction around the axis "d". Finally, the pitch chain 46 also drives a lower delivery roll sprocket wheel 60 mounted for movement around an axis "e". An idler sprocket wheel 62 completes the path of the chain back to sprocket wheel 48.
The drive system for the copy paper supply assembly includes a gear 64 adapted to be driven by the drum gear 18. A sprocket wheel 66 on a shaft common to the gear 64 is driven around an axis "f" to drive a pitch chain 68 in the direction of the arrow adjacent to the chain in FIGURE 1.
Chain 68 drives respective upper and lower paper supply roll sprocket wheels 70 and 72 mounted for movement around respective axes "g" and "h". A tensioning sprocket wheel 74 is arranged to give sufficient tension to the chain 68. All of the gear, sprocket wheel and pitch chain mechanism just described is located at the rear of the machine 10.
As can be seen by reference to FIGURE 2~ a spongy cleaner roll 76 mounted for movement around the axis "a~' is driven by gear 52 so that the surface of the cleaning roll in engagement with the drum moves in a direction opposite to the direction of movement of the drum surface~
A take-off roll 78, more fully to be described hereinafter, cooperates with a roller 80 to deliver a picked off sheet to the nip between a pair of intermediate conveyor rolls 82 and 84, the roll 84 of which is mounted for movement around the axis "c". After leaving the rolls 82 and 84, the sheet passes between a hold-down roller 86 mounted for bm :J ( ~23`~3 movement around the axis "d" so as to be brought into operative relationship with a dryer 88. As the sheet leaves the dryer 88, it enters the nip between delivery rolls 90 and 92, the lower roll 92 of which is mounted for movement around the axis "e". These rolls pass the copy to a tray 106, or the like.
The machine with which our pickoff is used includes two cassettes holding respective supplies 98 and 102 paper of different si~es. Respective paper feeding rolls 100 and 104 associated with the supplies 98 and 102 are mounted for movement at the axes "g" and "h". Means ~not shown) under the control of the operator is adpated to be actuated selectively to bring one or the other of the supplies 98 or 102 into cooperative relationship with its associated roller 100 or 104~ The operative roller delivers a sheet to the nip between a pair of feed rolls 94 and 96, the upper one of which is mounted for movement at the axis "f". Rolls 94 and 96 deliver the fed sheet to the surface of t~e drum 16. The structure thus far described is that of a machine to which my pickoff device is applied.
Referring now to FIGURE 3 to 6, gear 42, which is disposed in a housing 108 carried by a side of the machine, drives a shaft 110 extending out of the housing 108. My pickoff clutch assembly indicated generally by the reference character 112 includes a driver member or element 114, which is keyed to the shaft 110 by a key 116.
This key 116 is so arranged as to permit some radial movement of the clutch member 114 with reference to the shaft 110 for accurate positioning relative to the shaft in a manner to be described hereinbelow. Member 114 further is adapted bm:'~

~23~3 to receive a reduced end portion 118 to turn roller 70, the arrangement being such that ~Jhen the reduced end portion 118 is inserted into the member 114 roll 78 rotates with the member 114.
Housing 108 carries respective outwardly extending studs 120 and 122 which receive a bracket 124 secured to the studs by an~ suitable means known to the art.
A pin 126 carried by the bracket 124 intermediate its ends pivotally supports an arm 128, the end of which carries a shaft 129 which rota-tably supports a metal roller 130 having a ~nurled outer surface. A spring 134 wrapped around the pin 126 bears with one end against the bracket 124 and with the other end against the arm 128, so as to resiliently to urge the roller 130 into engagement with rubber rings 132 carried by clutch member 114.
The other clutch member or element 136 includes a disk-like portion on an integral axially extending hub portion 138 carried by a bushi~g 140 supported on the shaft 110. Respective ball bearings 142 and 144, the inner rings of which are received on the hub 138 are held in spaced relationship by a spacer 146 located between the outer rings of the bearings. These bearings 142 and 144 are received in a recess 148 formed in the clutch member 114~ Beaxings 142 ~ -and 144 accurately space clutch member 114 in a radial direction with reference to the hub 138 of the clutch member 136. As has been pointed out hereinabove, the key 116 permits some radial movement of the clutch member 114 relative to the shaft 110, thus to permit the bearings 142 and 144 to perform the function o~ accurately positioning the member 114 radially with reference to the hub 138 of bm: ;

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the member 136.
From the struc-ture -thus far described, it will readily be apparen-t that shaft 110 continuously drives the member 114 owing to the connec-tion therebetween provided by the key 116. Moreover, under the action of friction, member 136 likewise would tend to rotate with the shaf-t 110. I provide my clutch assembly with means for normally restraining member 136 against rotation with the shaft 110.
I form clutch 136 with a cam 150 having a low point 150a followed by a rising portion 150b in the counterclockwise direction as viewed in ~IGURE 6 and then a relatively sharp drop 150c, Stud 120 rotatably supports a follower arm 154 carrying a follower 152 adapted to ride against the cam 150. A spring 156 on the stud 120 normally urges the arm 154 to rotate in a clockwise direction as viewed in the drawings. In the inactive condition of the parts, ~ -follower 152 rests against the low 150a of the cam. In this condition the action of spring 156 on the arm 154 overcomes the frictional tendency of the clutch member 136 to rotate with clutch member 114, so that the clutch member 136 is stationary.
I form the disk-like portion of clutch member 136 with a peripheral axially extending finger 158 which extends for a predetermined distance around the disk-like portion of member 136. It will be seen that ~inger 158 forms a narrow radial gap with member 114. The radial extent of the gap is accurately determined by the bearinys 142 and 144. In practice the spacing between the finger 158 and the member 114 may be of the order of two mils. I provide a roughened surface portion 160 on the outer surface of bm:

~3~23 member 114 below the finger 115 and highly polish -the inner surface 162 of the member 158. As will more fully be explained hereinbelow, in operation of my clutch the surface 1~2 cooperates with the image bearing side of the copy sheet, while the surface 160 cooperates with the reverse side of the copy sheet. The space between the finger 158 and the member 114 is such that introduction of the leading edge of a sheet of common copy paper into the space between the finger and the member will clutch the inger and the member together with sufficient force to overcome the influence of spring 156 to cause the two members to move toyether. Moreover, as the two members move together, follower 152 rides up the rise 15Qb~ thus to increase the force with which the leading edge of the paper is gripped. As the paper is thus carried around with the two clutch elements in a clockwise direction as viewed in the drawings, ultimately the sharp drop 150c in the surface of cam 150 will arrive at the location of thç follower 152.
Moreover, as the follower 152 moved up the rise 150 r the force stored in the spring 156 increases. Thus, when the drop 150c arrives at the follower 152, the spring 156 rapidly moves clutch member 136 and finger 158 carried thereby in a clockwise direction but more rapidly than the speed of rotation of member 114, thus to release the portion of the leading edge of the copy which has been gripped by the clutch mechansim. It will readily be appreciated that the highly polished inner surface of finger 158 facilitates this releasing operation. Moreover, at the time of this releasing operation, the leading edge of the paper has already moved into the nip between the knurled roller 130 and the rubber bm:~c ~ ~ ~3~;~3 rings 132. From this point, the copy paper is carried out of the machine by means of the delivery rolls 82 and 84.
It is to be emphasized that under -the action of the cam and follower, finger 158 is brought precisely back to the same location on each operation of the machine~
I may employ any suitable means for directing the leading edge of -the sheet to be picked off into the space between the fingers 158 and member 114. For example, in the form of my apparatus illustrated in FIGURES 3 to 6, a thin finger 164 suppor-ted on a pivot 166 extending outwardly from housing 108 may be employed~ This finger which preferably is formed from a low friction material, such for example as polytetfluoroethylene has an edge which rests on the surface of drum 16, so as to intercept the leading edge of a sheet 168 of copy material and direct it into the space between finger 158 and clutch member 114.
Refexring now to FIGURE 7, in an alternate system any suitable means (not shown) might be employed to crimp the leading of the sheet to provide a raised portion 170 which is sufficiently spaced from the surface of drum 16 automatically to enter into the space between the finger 158 and the member 114. ~uch paper crimping devices are known in the art, such for example as that illustrated in U.S.
Patent 3,687,539, issued to Furuichi, for "Electrophoto- -graphic Apparatus".
Referring now to FIGURE 8, in still another form of the pickoff device, an air jet 172 may be employed to lift the leading edge or corner of the sheet 158 a sufficient distance from the surface of the drum 16 to cause it to enter into the space between finger 158 and the member 114.

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It will readily be appreciated that once the clutch mechanism has picked up the leading edge of a copy to be removed from the machine, it is not again in position to receive a second sheet until the copy has been delivered to the nip between the roller 130 and rings 132. It may happen in operation of any electrostatic copying machine of the image transfer type that in one cycle of the machine two sheets or lengths of copy material are fed from the supply toward the drum. Thus the danger exists that, while the first of the sheets may properly be picked off by the pickoff mechanism and received in the clutch, the second sheet will not be engaged by the clutch and may travel with the drum to the cleaning station at which it may become wrapped around the cleaning roll 76 with the attendant dangers pointed out hereinabove. I provide the machine 10 with means for obviating this possibility. More specifically, a shaft 176 supported on the housing of the machine 10 in any suitable manner pivotally carries one or more deflector members 176 at a location or locations spaced somewhat inboard of the clutch assembly 112. Each of the members 174 has a shoe portion 178 which rests on the surface of the drum 16. Any sheet which is not grasped by the clutch device is picked up by the shoe 178 which directs the leading edge thereof onto a surface 1~0 which causes the leading edge of the sheet to turn backwardly until it enters the nip between roll 130 and the rings ]32. Thus, the sheet is carried out of the machine along precisely the same path as is a copy sheet which is picked off in the usual manner.
The operation of my pickoff device will readily be understood from the description hereinabove. So long bm.~ ~J

;23~3 as the drum 16 is being driven, sh~ft 110 is driven to drive clutch member 114. At the same time, the action o~ spring 156 prevents rotation of clutch member 136 with the member 114. After an image has been formed on the drum 16 and developed, a sheet of copy material is fed to the drum beneath the trans~er corona 38. As the sheet moves past the transfer corona, the developed image migrates from the surface oE the drum to the surface of the sheet in contact with the drum. As a shee-t which has received the image moves out of the transfer location, its leading edge is caused to move into -the space between finger 158 and member 114. This may be as a rasult of the action of a pickoff finger 164 or as the result of a crimp or bend 170 formed in the leading edge of the paper, or under the action of an air jet 172 or any other suitable means. Owing to the relationship of the thickness of the sheet 168 to the space between finger 158 and member 114, as the leading edge of the sheet enters the space, the finger 158 and member 114 are clutched together to overcome the force of spring 156 and to cause the follower 152 to ride up the cam rise 150b.
As this occurs, the spring is loaded to increase the force with which the leading edge of the paper is grasped ~etween the finger 158 and the member 114. After a predetermined rotation of member 114 to a location at which the leading edge of the paper has moved into the nip between roller 130 and rings 132, the cam drop 150c has arrived at the location o~ follower 152. At this point the force of the loaded spring 156 moves the member 136 and finger 158 in the same direction and at a greater speed than the member 114 to release the leading edge oE the sheet. As has been pointed bm:,, out hereinabove, the highly polished surface 1~2 of finyer 158 facilitates this releasing action.
In addition to the foregoing, if by any chance a double feed occurs, the second sheet will be intercepted by the foot 178 of member 17~ and will be caused to move around to a point at which it is picked up by the nip between the roller 130 and rlngs 13~ and delivered to the user of the machine in the same manner as is an ordinary copy.
It will be seen tha-t I have accomplished the object~ of my invention. I have provided a pickoff for a copying machine which overcomes the defects of pickoff systems of the prior art. My pickoff device permits substantially the entire area of the copy sheet to receive a transferred image. My pickoff device is reliable in operation. My pickoff arrangement incooperates means for pxeventing a double fed sheet form becoming wrapped around the cleaning roller of the machine. It returns a double fed sheet to the user along the same path as does the copy sheet to which the imaye has been transferred. My device successfully picks a copy sheet off the drum and delivers it to the customer without smudging any part of the formed ~ -image and without dirtying the cop~.
It will b~ understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombination. This is contemplated by and is within the scope of my claims.- It is further obvious that various changes may be made in details within the scope of my claîms without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the bm:

~3~23 specific details shown and described.
Having thus described my invention, what I claim is:

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Claims (2)

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

1. In a copying machine of the image transfer type in which an image developed on a surface is transferred to a sheet of copy material which is fed to said surface from a supply of sheets and which moves with the surface through a transfer station to a pickoff station apparatus including a housing for said copying machine having a delivery opening through which copies are to be delivered to the user of the machine, conveyor means for receiving a sheet and delivering it through said delivery opening, first mechanical pickoff means comprising a mouth forming a narrow space approximately equal to the thickness of a sheet of copy material, adapted to receive the leading edge of a sheet, said first pickoff means adapted to be actuated to carry a sheet received in said mouth to said conveyor means, and auxiliary means adapted to direct the second sheet of a pair of double fed sheets from said supply, which second sheet misses said mouth, to said conveyor means to cause said second sheet to be delivered to the user without interruption of the opera-tion of said machine.

2. In a copying machine of the image transfer type in which an image developed on a surface is transferred to a sheet of copy material which moves with the surface through a transfer station to a pickoff station with a leading corner of said sheet normally moving along a path, apparatus including a housing for said copying machine having a delivery opening through which copies are to be delivered to the user of the machine, conveyor means for receiving a sheet and delivering it through said opening, first pickoff means positioned adjacent to said path for acting on a normally jb/ 20 conveyed sheet over a leading limited region adjacent to said path to remove said normally conveyed sheet from said surface and to deliver it to said conveyor means, and auxiliary means located relatively remote from said path for intercepting a copy sheet which misses said pickoff means and for guiding said intercepted sheet to said conveyor means to cause said conveyor means to deliver said intercepted sheet to the user.

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