DE2244249A1 - METHOD OF SUCCESSIVE FEEDING SEPARATE SHEETS FROM A STACK AND SHEET FEEDING DEVICE FOR PERFORMING THIS PROCEDURE - Google Patents

Description

22 5t £ DR. ING. E. HOFFMANN · DIPL. ING. W. EITLE DR. RER. NAT. K. HOFFMANN

PATEMTANWIME
D-8000 MÖNCHEN 81ARABEUASTRASSE 4 TELEPHONE (0811) 911087 224 A 24

Xerox Corporation, Rochester, N.Y. /UNITED STATES

Method for the successive conveyance of separate
Scrolling from a stack and feeding device to the

Implementation of this procedure

The invention relates to a method for successively conveying separate individual sheets from a stack of sheet material along a substantially
common path of travel and a sheet feeder for performing this method.

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The invention particularly relates to a folding machine with a storage compartment for sheets with a feed device for separating and conveying the top sheet from the stack for further treatment in the machine.

Duplicating machines which are intended to produce a Produce a large number of copies in quick succession, need suitable apparatus which ensures that a single sheet of material is removed from a stack of such Sheets are separated and can be easily fed through the machine. One sheet at a time comes from the top of the stack of sheets removed and expedient within the duplicating machine treated.

A known sheet feeding device is provided with a depositing table which carries the stack of sheets, separating devices are arranged at the front end of the depositing table and a feeding device conveys separated sheets one after the other from the stack. Typically, the feeder must be moved continuously, once to load the stack of sheets and each time a subsequent sheet needs to be conveyed from the delivery table, that is, the feeder moves with and out of engagement with the successive sheets. In a delivery device having one or more rotatable feed rollers for feeding the paper, the ratio of the feed rolls with respect to the paper is extremely critical. Each sheet of paper should preferably engage the feed rollers at the same point of tangency. Only then are all the paper sheets conveyed from the Ablegeti.sch in substantially the same path, ie tangentially with respect to the feed rollers at the point of contact with the same. The distance that each successive sheet travels is minimized by using a common path. In particular, if a common path is used, the sheet feeder can be made more compact than uü

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was previously possible if each subsequent leaf covered different paths. The commonality of the path for each subsequent one Blade reduces the work space required for movement of the following stages in the sheet feeder. This allows those belonging to the subsequent stages of sheet feeding To arrange mechanisms closely spaced from one another and essentially in a reduced size. It is therefore clear that the use of a common path on which successive separate top sheets are conveyed enables the size of the sheet feeder to be minimized. The aforementioned reduction in the size of the sheet feeder is particularly useful for duplicating machines the size of a desk.

The invention is therefore based on the object of a method of the type mentioned to create, in which the distance is reduced to a minimum on the path of movement for each subsequent separate top sheet,

This object is achieved according to the invention in that the stack sheet-like material from a rest position in which the uppermost Sheet of the stack arranged at a distance from the feeder is moved to a feed position in which the top sheet of the stack comes into engagement with the feeder that the top sheet of the stack is separated from the remainder of the stack and advanced, and substantially simultaneously with the separation and moving forward moves the remainder of the stack back to the rest position to enable the next successive top sheet to be fed along with the feeder for feeding it can be moved into engagement in a substantially identical path to the path traveled by the first-mentioned uppermost sheet.

Further, the invention provides a sheet feeding apparatus implementing this method which is so constructed is that a device for separating and conveying the top sheet from the stack of sheet material, a device for moving the stack of sheet material from a

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Rest position in which the top sheet of the stack is arranged at a distance from the separating and conveying device, in a conveying position in which the top sheet is in engagement with the separating and conveying device, and that one is provided with the separating and conveying device conveying device cooperating device for returning the rest of the stack is provided substantially simultaneously with the separation and conveying of the top sheet of the same in the rest position, so that by the device for moving the next top sheet in engagement with the separating and conveying device for conveying the same is movable in a substantially identical path to the path traveled by the first-mentioned uppermost sheet.

Further objects and advantages of the invention will become apparent from the following detailed description with reference to the drawing. Show it:

1 shows a diagram of a preferred embodiment

a duplicating machine with a sheet feeding device according to the invention,

Fig. 2 is a perspective view of the sheet feeding device of Fig. 1,

Fig. 5 is an enlarged partial view of the sheet feeding device when buckling the top sheet of the stack,

Fig. 4 is an enlarged partial view of the sheet feeding device conveying the top sheet from the stack;

Fig. 5 is an enlarged partial view of the sheet feeding device; with the stack disengaged from the feed rollers,

Fig. 6 is an enlarged partial view of the sheet feeding device loaded stack, and

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7 is an enlarged partial view of the stack as it is in a feeding position in the sheet feeding device is arranged.

While the invention is in connection with a preferred embodiment is described, it goes without saying that it is not intended to apply the invention to this exemplary embodiment and method of application. On the contrary, it is intended that all alterations, modifications and equivalents that come within the spirit and scope of the invention, as defined by the following claims are included are.

Pig. Fig. 1 schematically shows the operation of a sheet feeding device in a conventional duplicating machine such as a xerographic copier. Fig. 2 is a perspective Representation of the feed device of Fig. 1, which the new provided therein device for separating and conveying successive showing the top sheet of the stack. FIGS. J to 5 inclusive show the successive steps when buckling the top sheet, conveying the sheet and returning it the rest of the stack to its original rest position. Finally, Figures β and 7 show how the stack is fed into the sheet feeder is loaded for conveying the top sheet from the stack, Fig. 1 is generally described below in order to to illustrate the assignment of the sheet feeder to the duplicating machine, while with reference to Fig. the structure of the sheet feeding device will be described. Based on FIGS. 3 to 5 inclusive, this is primarily Methods for separating and conveying consecutive sheets are described. With the help of FIGS. 6 and 7, the type and The manner in which the stack is loaded into the sheet feeder will be described.

As schematically shown in Fig. 1, the copying machine comprises an image bearing member including a

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photographically conductive layer or light-receiving surface on a conductive background, which is in the form of a drum is formed and is denoted by the reference number 10. The drum 10 is mounted on a shaft which is mounted in a frame so that it can rotate in the direction indicated by arrow 12, so that the surface of the drum successively passes through several processing stations.

In the present case, for illustrative purposes, it is used as a duplicating machine a xerographic copying machine has been chosen, which has different processing stations on the way of the drum 10 has. Station A is a charging station with a spray charging device 14 for applying a uniform electrostatic charge to the photographically conductive layer of Drum 10. Subsequently, an exposure station B is arranged in the path of movement of the drum 10. The exposure station B has an optical scanning system 16, preferably of the type described in U.S. Patent 3,062,094, which projects a light or a ray pattern of the copy to be reproduced onto the surface of the drum 10. That Light consumes the drum charge on the exposed parts and thereby draws a latent electrostatic image of the parts to be reproduced Copy on. Following the exposure station is a development station C with a development device 18 arranged. The developing device cascades developing material onto the drum 10. The developing material contains toner particles with an electrostatic charge, which is opposite to that of the electrostatic latent image on the surface of the drum 10. When the developing material falls over the drum 10, the toner particles adhere the electrostatic image to form a powder image in the form of the copy to be duplicated. Closest to development station C. and subsequently a transfer station D including a sheet feeding device 20 and a spray transfer device are arranged 22. The sheet feeder 20 guides

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successive sheets to the drum 10 in relation to time to them so that they coincide with the presence of a developed image on the drum 10 at the transfer station D. The spray transfer device 22 is located immediately after the point of contact between the sheet being conveyed and the drum 10. That through the spray transfer device 22 generated electrostatic field is effective to the toner particles, which the powder image of the Surface of the drum 10 'to attract' and cause them to electrostatically adhere to the leading sheet. Immediately following the transfer station D, a suitable spray discharge device 24 is arranged, which the neutralized electrostatic adhesion of the leading sheet to the drum 10 and separates the sheet from her. The sheet moves is then on the conveyor 26, which it to a fixing device 2o applies to the transferred powder image permanently to fix the sheet. After fusing, the finished copy is collected from the copier at a convenient point ejected outside the copier. The next and last station in the copier machine is a drum belt station E. The drum cleaning station has a drum cleaning device 50 which removes any remaining toner particles that have stuck to the Surface of the drum 10 remained after the image transfer, removed.

The following is the object of the invention, the sheet feeding device 20, which in the image transfer station for successively feeding sheets, e.g. can be transferred to the paper. It has a filing table for holding a stack of sheet material, Feed rollers for separating and conveying a single sheet of the stack, an alignment part for aligning the leading one

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Sheet, conveyor rollers for conveying the sheet after alignment and an appropriate drive for coordinating the Times of feeding the successively separated sheets in contact with the drum for accurate alignment of the powder image on the drum with the paper on.

As seen in Figure 2, the sheet feeder 20, which feeds successive sheets of paper in timed relation to the appearance of developed images on the drum, preferably includes a pair of feed rollers 32 and 34, usually made of rubber or similar material, and cooperating are positioned together in front of tabs 36 and jfc which "aid in separating the advancing paper from the remainder of the stack 40. It should be understood, however, that one roll would work satisfactorily instead of two. Feed rolls 32 and 3 ^ convey the top sheet of the Stack 40 over the noses 30 and 30 between the conveyor rollers 42 and 44 until the leading edge of the leading sheet grips the alignment part 46. This is achieved by a suitable endless drive 46 operating with belts or link chains, which drives a cam 50 in the direction of the arrow 52. A toothed segment 54 is connected to the cam 50 by means of a suitable spring r 56 resiliently held in engagement. The cam 50 drives the toothed segment ^ k to oscillate. The gear segment meshes with the pinion 5 & to rotate it counterclockwise and clockwise. Because the pinion 5 & and the feed rollers 32 and 34 are arranged on a common shaft 61, the rollers 32 and y \ rotate together with the pinion 5b, as indicated by the arrow 60. The feed rollers 32 and 3 ^ rotate intermittently and are suitable for gripping the top sheet of the stack, which is arranged on the delivery table 62. The delivery table has a pivotable base plate 64 on which the stack 40 of the sheet material is arranged. The entire sheet feeder 20 is within a suitable storage compartment

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the duplicating machine arranged. A resilient device 66 is disposed in the storage compartment to engage the base plate 64 and pivot it up and down. The base plate 64 can be pivoted so that the top sheet of the stack 40 engages the feed rollers 32 and 3 ² J-which are fixedly attached to the supply compartment by the shaft 61 and remain stationary relative thereto. The drive 48 rotates the shaft 6t with the cam 70 arranged thereon. The cam 70. in turn drives the follower 72, which is attached to a common shaft 74 with the noses J> 6 and 3 &. The lugs 36 and 3o thereby pivot synchronously with the feed rollers 32 and 34 to grasp and release the top sheet of the stack 40 at the appropriate time, ie the shaft 7 ² I- rotates both clockwise and counterclockwise, as is indicated by the arrow 76. Preferably, tabs 36 and 3 & 4 are self-aligning, that is, they are conveniently attached to shaft 74 so that they are vertically movable and laterally pivotable so that they place their horizontal surface at right angles on the top sheet of the stack. An alignment roller 44 is arranged on the shaft 69, which is driven by a suitable drive system, not shown. A cam 78, which is fastened on the shaft 68, drives a follower So, which in turn causes the connecting link 82 to pivot in the direction of the arrow 84. A shaft 06 and a rod 88 are attached to the connecting link 82. In this way, the shaft 86 on which the feed roller 42 is mounted can bring the feed roller into and out of engagement with a leading sheet which is traveling over the feed roller 44. The leading sheet travels between the closely spaced feed rollers 42 and 44 and the leading edge engages the registration member 46. Thereafter, the link 82 pivots to bring the feed roller 42 down into engagement with the leading sheet and move the registration member 46 down to disengage it from the leading edge portion of the moving sheet. The sheet is timed on it in a

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matched relationship to the image on the drum 10 for Image transmission station D promoted. It goes without saying that the The workflow of the sheet feeding device 20 is controlled by the drive, which in turn is connected to the input drive of the Copying machine is engaged via a suitable coupling, not shown, which is also not shown suitable magnet operated by the optical scanning system is switched on. In this way, the sheet feeding device held in timed relationship with the image on drum 10 to align the ensure leading sheet with the picture.

In Fig. 3, the base plate 64 is through the device 66 after moved up, as indicated by arrow 85, to bring the top sheet 41 with the feed rollers 32 and 34 into engagement. The flap 69 of the filing table 62 is when the cassette is being loaded has been pivoted counterclockwise into the copier to release its lip from the top sheet of the stack. the Feed rollers 32 and 34 rotate counterclockwise as well shown by arrow 90 to move the top sheet 41 of the stack 40 rearward. The backward movement of the Sheet 41 creates a hump in the sheet and makes it easier to separate the sheet from the remaining sheets of the stack Also in Pig. 3 shows how the conveyor rollers 42 and 44 are spaced apart, and the alignment flap is pivoted up to its closed position. In the present example, the conveyor roller 44 is continuously driven, regardless of whether the feed roller 42 is engaged with a sheet or not. When the top sheet 41 moves backwards, it slides out from under the noses 36 and 38. The noses 36 and 38 fall down onto the next following top sheet of the stack 40.

In Fig. 4 the direction of rotation of the rollers 32 and 34 is reversed, as indicated by arrow 92. The sheet 41 is now in

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Direction of arrow 93 promoted via lugs 36 and 38, until its leading edge abuts the alignment part 46. The conveyor rollers 42 and 44 are spaced apart so that the sheet 41 can be brought between them. The leading edge, of the sheet 41 being conveyed abuts against the alignment member 46 and a bump is created in the sheet. By bumping into the Front edge of the sheet 41 to the alignment member 46 generated humps eliminates any lateral inclination of the sheet 41. This ensures that the image transferred from the drum is properly registered with sheet 41. After the leading edge of the Blade 41 has come into engagement with the alignment member 46 and a slight hump is created therein, becomes the alignment member moves downward when the feed roller 42 is moving in the downward direction moved to contact the sheet 41 and bring it into engagement with the feed roller 44 which is in the direction of the arrow 4j5 rotates to continuously feed the sheet forward.

When, as shown in FIG. 5, the conveyor roller 42 moves downward, as indicated by the arrow 97, in order to bring the sheet ² II into engagement with the conveyor roller 44, the lugs 36 and L pivot the base plate below, by applying a force of sufficient magnitude to the same to overcome the force exerted on them by the resilient means 66. In addition, at the same time as this, the alignment member is pivoted downward, as indicated by arrow 95, so that the sheet 41 can run past and into engagement with the drum 10.

In this way, the feed rollers 32 and 34 rotate only about the shaft 61 and do not move sideways with respect to the storage compartment. In contrast, the stack 40 arranged on the base plate 64 is pivoted into and out of engagement with the feed rollers 32 and 34. It is to be noted that in this embodiment successive uppermost sheets of the stack 32 and 34 the same of the sheet material to the feed rollers substantially i ^m

BATH ORIGINAL

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Capture circumferential point in order from there tangentially to essentially the same common path forward.

6 and 7 it can be seen that a loading arm 9h, which is pivotally attached at one end to a suitable hinge 96 with a coil spring 98, is pushed substantially downward by hand so that the stack of sheet material thereon is pressed can be loaded without touching the feed rollers 32 and 32. When the arm 100 of the lever 96 is released, the loading arm pivots upwardly in a counterclockwise direction to pivot the base plate 64 upwardly to a loaded position in which the top sheet of the stack 40 can engage the feed rollers 32 and 34.

To ensure that the leading sheet hits the drum in register with the electrostatic image on it, the distance is the center line of the drum and the Alignment flap as a function of the speed of rotation of the drum, the conveyor rollers, the feed rollers and the corresponding distances in between determined. For example, a drum having a diameter of £ -4 mm (3 * 3 ") delivers at a rotational speed of rc mm / sec. (3.456 "/ sec.") Approximately 20 copies per minute. Preferably the conveyor and feed rollers rotate at substantially the same peripheral speed as the drum.

Thus it is clear that the invention is capable of the various To achieve the goals and tasks described above. In summary, the consecutive separated uppermost one Sheets are conveyed from the stack along a substantially common path to minimize the distance of its path to reduce.

So it is clear that according to the invention a method and an associated Sheet feeding devices were created that completely

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fulfill the tasks, goals and advantages described above. While the invention has been described in connection with a particular embodiment, it will be understood that many Changes, modifications and variations for the Faclunann im Are possible with regard to the preceding description. Therefore, the following claims are intended to include all such changes, modifications and include variations as come within the spirit and broad scope of the invention.

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Claims (1)

P at en t claims Method for successively conveying separate individual sheets from a stack of sheet-shaped sheets Material along a substantially common path of travel, characterized in that the stack sheet-like material from a rest position in which the uppermost Sheet of the stack is arranged at a distance from the feed device, is moved into a feed position in which the top sheet of the stack comes into engagement with the feeder that the top sheet of the stack is separated from the rest of the stack and is moved forward, and substantially simultaneously with the separation and advancement of the remainder of the stack to the rest position is moved back to enable the next successive top sheet to be fed with the feeder to advance it along one substantially to that of the first-mentioned uppermost Sheet traveled path identical path can be moved into engagement. 2. The method according to claim 1, characterized in that the stack of sheet material when Conveying from the rest position is carried on a base plate in the rest position and the base plate is resilient around a fulcrum is pushed substantially in an upward direction to bring the stack of sheet material thereon into the feed position in which the first-mentioned top sheet engages the feeder. J. The method according to claim 2, characterized in that the top sheet when separating and conveying is moved in the rearward direction to buckle it from the remaining sheets of the stack of sheet material. 309826/0255 k. A method according to claim 3 / characterized in that the leading sheet is arranged during separation and conveyance between a pair of closely spaced conveyor rollers, the sheet is aligned by bringing its leading edge into engagement with an alignment part, the alignment part out of the path of movement of the to conveying sheet is removed vrlrd and substantially simultaneously with the retraction of the alignment member, the pair of conveying rollers is brought into engagement with the interposed sheet to be conveyed. 5. Method according to one of the preceding claims, the sheets to .einem an image bearing part of a reproduction machine be promoted, thereby ge k e η η draws that the separation and conveying of the top sheet of the stack from the rest of the stack in a timed manner Relationship to the image-bearing part of the reproduction machine is carried out to ensure that the conveyed Sheet touches the part bearing the image in alignment with the image recorded on it. 6. sheet feeding device for performing the method according to any one of the preceding claims, characterized in that a device (32, 3 * 0 for separating and conveying, the top sheet (41) from the stack (40) sheet-shaped Material and means for moving the stack of sheet material from a rest position in which the topmost Sheet of the stack is arranged at a distance from the separating and conveying device, in a conveying position in which the top sheet is engaged with the separating and conveying means, and that one with the separating and funding institution cooperating institution (36, Jh) to return the rest of the stack essentially simultaneously is provided with the separation and conveying of the top sheet of the same in the rest position, so that by the device the next following top sheet engaged to move - 16 309826 / 025S with the separating and conveying device for conveying the same is movable in a substantially identical path to the path traveled by the first-mentioned uppermost sheet. 7. Sheet feeding device according to claim 6, characterized in that the means for moving comprises a base plate (64) with a generally flat surface which supports the stack (4o) of sheet material, the base plate is pivotably arranged in the sheet feeding device (20) and means (66) are provided for pivoting the base plate substantially in an upward direction for engagement of the top sheet (41) of the stack with the means for separating and conveying. and sheet feeding device according to claim 7 *, characterized in that the means for pivoting consists of a resilient means (66) for resiliently pressing the base plate to pivot the same substantially in the upward direction, so that the top sheet (41) of the stack (40) with the means (32, J4) for separating and conveying can be brought into engagement. 9 · sheet feeding device according to claim o, characterized in that the device for separating and Conveying comprises at least one feed roller (32, 3 ^) rotatably arranged in the sheet feeding device and a device (50-58) for rotating the feed roller in one direction to separate the top sheet (41) into engagement therewith from the rest Stack (40) and in the other direction for conveying the the top sheet from the rest of the stack is provided. 10. sheet feeding device according to claim 9, characterized in that, the means for separating and Convey an alignment part (46) for aligning the conveyed - 17 - 309826/0255 - - 17 - Sheet (41) in engagement therewith by the feed roller (32,33), the registration member is generally vertical Has surface with which the leading edge of the conveyed sheet is engaged and coupled to the base plate (64) is so that it corresponds to the movements of the base plate movable in and out of the path of each subsequent sheet being conveyed. 11. sheet feeding device according to claim 10, characterized in that the means for separating and conveying at least one nose (j5ö, j5c) on v / eist, which one substantially horizontal surface engaging part of the top sheet (41) of the stack (40) and one substantially has vertical surface in engagement with the front part of the stack, and that the nose pivotable laterally and vertically is movably arranged on the sheet feeding device (20). 12. The sheet feeding device according to any one of claims 6 to 11, v / calibrated in a duplicating device of the art is used, plural marriage a storage compartment for holding a stack having sheet material therein and a movable, image-bearing portion, characterized in that that the device for separating and conveying the top sheet (41) from the stack (4o) is designed so that the separation and Conveying takes place in a timed relationship with the image-bearing part, which ensures that the sheet being conveyed the image-bearing part in alignment with that recorded on it Image touches. 13 sheet feeding device according to claim 12, characterized in that the base plate (64) is pivotable is arranged in the storage compartment. 14. Sheet feeding device according to claim 12 or 15, characterized in that the feed roller (32, 34) is rotatably arranged in the storage compartment. - 18 -. 309826/0255 - 15 - 15. Sheet feeding device according to one of the claims 12 to 14, characterized in that the nose (j6, 38) is arranged in the storage compartment. 309826/0255 Blank page