Inverter-reverser For A Reproduction Machine

Abstract

A reproduction machine adapted for producing copies of an original on either or both sides of a copy sheet and forwarding the finished copy to a collator. To collate the produced copy in the proper orientation, an inverter-reverser is employed to allow single sided copy to pass directly to the collator, route single sided copy to a secondary feed tray for subsequent processing to allow copying on the reverse side of the sheet to produce duplex copies, and for inverting duplex copies prior to delivery to the collator to provide the required sheet orientation in the collator.

Description

BACKGROUND OF THE INVENTION

In recent years a number of high volume electrostatic copy machines have been introduced. In order to take advantage of the high speed copying capabilities of these machines, document handlers adapted to feed the documents to be copied to the platen of the copy machine and remove them therefrom have been utilized to reduce the time required for an operator to place and remove documents. Further, to cope with the large quantities of copies produced, collators of the type illustrated in U.S. Pat. No. 3,830,590, commonly assigned with the instant application, have been introduced for collating the copies to minimize operator involvement with the copying process. Following these developments, the need for a reproduction machine which would reproduce on both sides of a sheet of paper, ordinarily referred to as duplex copying was recognized. This presents a number of problems in a copy reproduction system adapted to produce both single sided copy and duplex copy in that the machine must be capable of routing single sided copy sheets directly to the collator, must be adapted for returning single sided copy sheets to a paper supply tray in preparation for copying on the opposite side of the sheet to produce duplex copies, and must be adapted to invert the duplex copy to provide the proper orientation thereof prior to passage to the collator if the correct page order is to be maintained so that the finished copies are ready for stapling or binding without operator involvement. Card inverting mechanisms of the type illustrated in U.S. Pat. No. 2,901,246 and sheet inverting mechanisms of the type illustrated in U.S. Pat. No. 3,523,687 are well known in the art. However, the known inverters are unacceptable for use in a high speed reproduction system adapted for producing copies on sheet material of the type normally encountered in a copy reproduction machine which is ordinarily capable of handling a wide range of paper weights.

At the high speeds encountered, an inverter-reverser must be provided that will positively handle light weight paper without damaging the leading or trailing edges of the paper. For heavy weight paper, the device must be capable of coping with the high inertial forces necessary for inverting the sheets at high speed. Further, since a wide variety of paper stock may be encountered, the device must be capable of handling sheets having fairly large size tolerances.

It is therefore an object of this invention to provide a mechanism adapted for handling single sided or double sided copy sheets to route the copy sheets to a collator, or if duplex copies are required, to route the single sided copy to a duplexing paper tray and after the duplex copy is produced, invert the duplex copy sheet to provide the proper sheet orientation in the collator.

SUMMARY OF THE INVENTION

This invention relates to a reproduction system including a copy reproduction machine and a collator, transport means being provided to direct single sided copy through a first path to the collator deflector, means being provided to intercept single sided copies prior to passage to the collator to deflect the copies through a second path to a location wherefrom the sheets are refed through the reproduction machine to provide duplex copies, the deflector being adapted to intercept the duplex copy for passage through a portion of the second path, means being provided in the second path for contact with the lead edge of the copy sheet to stop passage thereof, feed means being adapted for contact with the trailing edge of the intercepted sheet to feed the paper in the reverse direction to the collator for collation therein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an electrostatic reproduction system including an electrostatic reproduction machine and a collator;

FIG. 2 is a schematic view of the inverterreverser mechanism employed with the reproduction system of FIG. 1 illustrating a first position of the various components thereof to allow single sided copies produced by the reproduction machine to pass directly to the collator for collation therein;

FIG. 3 is a schematic illustration of the inverter-reverser mechanism illustrating a second position of the various components thereof to intercept a single sided copy from the reproduction machine for returning the copy to a duplex copy tray in the reproduction machine for subsequent processing to produce double sided or duplex copy; and,

FIG. 4 is a schematic illustration of the inverter-reverser apparatus employed in the reproduction system with the elements thereof in a position to intercept the completed duplex copy for inverting the copy sheet for subsequent passage to the collator for collation therein in the proper paged order.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For a general understanding of an electrostatic processing system in which the invention may be incorporated, reference is had to FIG. 1. In the illustrated machine, an original D to be copied is placed upon a transparent support platen P fixedly arranged in an illumination assembly generally indicated by the reference numeral 10. While upon the platen, an illumination system flashes light rays upon the original thereby producing image rays corresponding to the information areas on the original. The image rays are projected by means of an optical system 11 to an exposure station A for exposing the photosensitive surface of a moving xerographic plate in the form of a flexible photoconductive belt 12. In moving in the direction indicated by the arrow, prior to reaching exposure station A, that portion of the belt being exposed would have been uniformly charged by a corona device 13 located at the belt run extending between belt supporting rollers 14 and 16. The exposure station extends between the roller 14 and a third support roller 15.

The exposure of the belt surface to the light image discharges the photoconductive layer in the areas struck by light, whereby there remains on the belt a latent electrostatic image in image configuration corresponding to the light image projected from the original on the supporting platen. As the belt surface continues its movement, the electrostatic image passes around the roller 15 and through a developing station B located at a third run of the belt wherein there is provided a developing apparatus generally indicated by the reference numeral 17. The developing apparatus 17 comprises a plurality of brushes 17' which carry developing material to the adjacent surface of the upwardly moving inclined photoconductive belt 12 in order to provide development of the electrostatic image.

The developed electrostatic image is transported by the belt 12 to a transfer station C located at a point of tangency on the belt as it moves around the roller 16 whereat a sheet of copy paper is moved at a speed in synchronism with the moving belt in order to accomplish transfer of the developed image. There is provided at this station a transfer roller 18 which is arranged on the frame of the machine for contacting the non-transfer side of each sheet of copy paper as the same is brought into transfer engagement with the belt 12. The roller 18 is electrically biased with sufficient voltage so that a developed image on the belt 12 may be electrostatically transferred to the adjacent side of a sheet of paper as the same is brought into contact therewith. There is also provided a suitable sheet transport mechanism 19 adapted to transport sheets of paper seriatim from a first paper handling mechanism 20 or a second paper handling mechanism 21 to the developed image on the belt as the same is carried around the roller 16. A programming device operatively connected to the mechanisms 20, 21 and the illumination device for producing an electrostatic latent image on the belt 12, is effective to present a developed image at the transfer station C in time sequence with the arrival of a sheet of paper.

The sheet is stripped from the belt 12 after transfer of the image thereto by a stripper transport 23 and thereafter conveyed by the stripper transport into a fuser assembly generally indicated by the reference numeral 25 wherein the developed and transferred xerograhpic powder image on the sheet is permanently affixed thereto. After fusing, the copy is either discharged from the reproduction machine into the collator 24 or routed back to paper handling mechanism 21 in a manner to be hereinafter described. The toner particles remaining as residue on the developed image, background particles, and those particles otherwise not transferred are carried by the belt 12 to a cleaning apparatus positioned on the run of the belt between rollers 14 and 16 adjacent the charging device 13. The cleaning device, comprising a rotating brush 26 and a corona emission device 27 for neutralizing charges remaining on the particles, is connected to a vacuum source (not shown) for removing the neutralized toner particles from the belt prior to the formation of subsequent images thereon.

Referring now to FIGS. 2, 3, and 4, there is illustrated an inverter-reverser mechanism adapted to receive copy sheets from the fuser 25 and route the fused copies either to the paper handling mechanism 21 or the collator 24.

The inverter-reverser mechanism includes a first transport 30 adapted to receive fused copies from the fuser for transport to the collator. When the reproduction system is being utilized to produce one sided copy, the sheets from the fuser are transported by transport 30 directly to the collator 24 as illustrated in FIG. 2. When double sided or duplex copies are to be produced, copies on the transport 30 are intercepted by a deflector 32 which is adapted for movement into the sheet path as illustrated in FIGS. 3 and 4. With the deflector 32 in the intercept position, the sheets are carried around a feed roll 34 and through the nip formed by roll 34 and a cooperating roll 36. The sheet is advanced by rolls 34, 36 between an upper sheet guide baffle 46 and a lower sheet guide baffle 48 to a second feed roll pair 38, 40 which further advance the sheet to a transport mechanism 42 (see FIG. 1) which carries the sheet to paper handling mechanism 21. When the desired number of one sided copies have been produced and delivered to the paper handling mechanism 21, the paper handling mechanism 20 may be inactivated and the paper handling mechanism 21 activated. It should be understood that in following the paper path around roller 34 and between feed roll pair 38, 40, the copy sheets are turned over, i.e., the printed material is on the top of the sheets in paper handling mechanism 21.

Upon re-energization of the machine, the sheets from paper handling mechanism 21 are fed through the reproduction machine for copying on the blank side of the sheet in the same manner as described heretofore. As the duplex copy is exited from the fuser it is carried by the transport 30 around roll 34 as illustrated in FIG. 4 and between rolls 34, 36.

Simultaneously with the activation of the machine for producing the duplex copy, a suitable sheet stop 44 is raised into the paper path between the upper guide baffle 46 and the lower guide baffle 48. Feed roll 40 may be mounted on upper baffle 46 so that upon raising baffle 46, feed roll 40 is displaced away from lower feed roll 38 so that papers fed therebetween are not forwarded thereby. The sheet stop 44 is formed of a resilient material such as a doughnut or ring shaped, flexible, polyurethane foam having a very low local and bulk spring rate. The foam ring does not damage light paper and is compliant enough to accept a large mass range (6.0:1) and adequate length range (approximately one-half inch variation in sheet length) without adjustment. Recovery of the foam ring to its circular shape is used to insert the sheet into the nip formed between roll 36 and a cooperating roll 50, the trailing edge of the sheet being carried by roll 36 into the nip. The rolls 36 and 50 are formed of a high friction material such as polyurethane foam to assure positive feeding of a sheet travelling toward stop 44 and positive feeding of the sheet travelling away from stop 44 against the drag force generated between two sheets which may be in the inverter area at the same time travelling in opposite directions.

In the illustrated embodiment, the collator, of a type illustrated in U.S. Pat. No. 3,380,590 mentioned heretofore, is adapted to receive single sided copy face down for collation purposes. Stated another way, single sided copy entering the collator is deposited in the collator trays face down so that the informational material on page one is at the bottom followed by the informational area on the succeeding page etc. to provide collated booklets or reports having the proper page orientation. Thus, when employing the collator with duplex copy, page one must also be presented to the collator face down. Since the duplex copy exits from the fuser with page two down, the inverter inverts the copy to present the duplex copy to the collator with page one down. The subsequent sheet, having pages three and four thereon would be presented to the collator with page three down etc. to provide correct numerical order of the sheets in the tray.

The disclosed reverser-inverter device is capable of extremely high speed operation without damaging the sheets presented thereto, irrespective of the weight of the sheets or normally encountered variations in the size of the sheets.

Further, by reference to the drawings it can be seen that the inverter portion of the disclosed mechanism is obtained by the simple addition of the stop 44 and roll 50, resulting in a very simple yet effective inverter which requires minimal space in the reproduction machine.

While I have described a preferred embodiment of my invention, it is to be understood that the invention is not limited thereto but may be otherwise embodied within the scope of the following claims.

Claims

What is claimed is:

1. A reproduction system for producing single sided and double sided copy comprising:

a reproduction machine including a first sheet handling means and a second sheet handling means for feeding sheets seriatim through said reproduction machine to produce copy thereon;

transport means associated with said reproduction machine for transporting sheets having copy thereon through a first path to a location external of said reproduction machine;

deflector means associated with said transport to deflect copies from said transport along a second path to said second sheet handling means;

resilient stop means adapted for movement into said second path for contacting the leading edge of a sheet passing therethrough to stop the sheet and reverse the direction of movement thereof; and

feed means adapted for contact with the edge of the sheet opposite the edge contacted by said stop means for feeding the sheet into said first path for delivery of the sheet to a location external of said reproduction machine.

2. A reproduction system according to claim 1 further including a first feed roll and a second feed roll forming a first feed roll pair, said deflector means being adapted to deflect sheets between said first feed roll pair for movement of the sheets into said second path; and,

third and fourth rolls forming a second roll pair along said second path downstream from said first roll pair, said third and fourth rolls being mounted for movement relative to each other, said resilient stop means being located immediately downstream from said second roll pair, said third and fourth rolls being movable away from each other when said stop means is moved into said second path, movement of said third and fourth rolls away from each other effectively negating the sheet feeding capability of said second roll pair.

3. A reproduction system according to claim 2 wherein said feed means includes a fifth roll, said fifth roll being adapted for cooperation with said second roll to form a third roll pair, reversal of the sheet movement by said resilient stop means causing the edge of the sheet opposite said stop means to be engaged between said third roll pair for movement in a direction away from said stop means into said first path for delivery of the sheet to a location external of said reproduction machine.

4. A reproduction system according to claim 1 wherein said resilient stop means is comprised of a resilient ring, contact of the lead edge of a sheet with said ring causing said ring to collapse, recovery of the ring to its circular shape causing the sheet to move in a direction opposite to the direction from which the sheet struck said stop.

5. A reproduction system according to claim 4 wherein said resilient ring is formed of polyurethane foam having a very low local and bulk spring rate to prevent damage to light sheets, said stop ring being compliant enough to accept a large range of sheet mass.

6. A reproduction system according to claim 4 further including a collator, said sheets being fed through said first path to said collator for collation therein.

7. A reproduction system according to claim 1 further including upper and lower guide means defining said second path downstream from said first roll pair, said third roll being mounted adjacent said lower guide means for contact with sheets passing therealong, said fourth roll being mounted on said upper guide means, said upper guide means being movable away from said lower guide means when said stop means is moved into said second path, movement of said upper guide means and said fourth roll away from said third roll effectively negating the sheet feeding capability of said second roll pair.