US3240486A - Paper transport mechanism - Google Patents

Description

March 15, 1966 R. F. REILLY PAPER TRANSPORT MECHANISM l4 Sheets-Sheet 1 Filed Dec. 2 1963 INVENTOR. RICHARD F. REILLY BY A T TORNEY March 15, 1966 REILLY 3,240,485

PAPER TRANSPORT MECHANISM MOT-3 INVENTOR. 2 RICHARD F. REILLY BY-W M 7242a A T TOR/VE V March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 5 INVENTOR. l RICHARD F. REILLY A T TORNEY March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 4.

INVENTOR. RICHARD F. REILLY BY ww A T TORNE V March 15, 1966 Filed Dec. 25, 1963 R. F. REILLY PAPER TRANSPORT MECHANISM 14 Sheets-Sheet 5 ATTORNEY March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 6 INVENTOR. RICHARD F. REILLY A T TORNE Y FIG. 6

14 Sheets-Sheet '7 Filed Dec. 23, 1963 A T TORNE V w Rl m m VF mD R A H m March 15, 1966 REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1965 14 Sheets-Sheet 8 FIG. 8

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INVENTOR. FIG. /0 RICHARD F. REILLY A T TORNE Y March 15, 1966 R. F. REILLY PAPER TRANSPORT MECHANISM 14 Sheets-Sheet 9 Filed Dec. 23, 1963 INVENTOR. RICHARD F. REILLY FIG. /2

u r F A T TORNE Y March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 10 OOOOOOOI lull m I M 0 00 0 O O] =T "'l!]| a g a l. "P goooooool |m LE 0 o o o o 0 O I I [IN [@l G l 4, ,8 2:

INVENTOR. RICHARD F. REILLY @gi yrAizgm A TTOR/VE Y March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 11 INVENTOR. 4 RICHARD F. REILLY A TTORNE Y March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 12 FIG. /5

INVENTOR. RICHARD F. REILLY A T TORNE V March 15, 1966 R. F. REILLY 3,240,486

PAPER TRANSPORT MECHANISM Filed Dec. 23, 1963 14 Sheets-Sheet 14 lCR-3 INVENTOR. RICHARD F. REILLY IOCR-Z A T TORNE Y FIG. /7 4/24 United States Patent 3,240,486 PAPER TRANSPORT MECHANISM Richard F. Reilly, Webster, N.Y., assignor to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Dec. 23, 1963, Ser. No. 332,462 1 Claim. (Cl. 271-49) This invention relates in general to xerographic apparatus and, in particular, to a sheet feed mechanism adapted to feed sheets one at a time to a xerographic drum.

More specifically, the invention relates to an improved paper transport mechanism that is particularly adapted for use in a xerographic reproducing apparatus and is also suitable for use with comparable types of devices In automatic xerographic apparatus adapted to etfect reproductions on cut sheet material, it is necessary tofeed sheets one at a time to the xerographic plate in proper registration with the powder image formed on the xerographic plate whereby the powder image is transferred to the sheet material.

It is, therefore, the principal object of this invention to improve sheet feeding mechanism for seriatim feeding of sheets in timed relation with the formation of the powdered image on the xerographic plate of an automatic xerographic reproducing apparatus.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 illustrates schematically a preferred embodiment of a xerographic apparatus having a paper transport mechanism constructed in accordance with the invention;

FIG. 2 is a top view of the xerogra-phic apparatus with the xerographic drum, developer assembly and cleaning assembly removed;

FIG. 3 is a perspective view of the optical system of the invention and the top drive for the various inoperative elements associated with the xerographic drum;

FIG. 4 is a front view of a portion of the paper transport mechanism;

FIG. 5 is a view similar to FIG. 4 with parts broken away to show the elements of the transport mechanism including the paper reject mechanism and the paper registering mechanism;

FIG. 6 is a top view of a portion of the paper transport mechanism to the right of the xerographic drum;

FIG. 7 is a sectional view showing the paper registrations stops and feed rollers of the paper transport;

FIG. 8 is an enlarged front view of the double sheet sensing device of the paper transport;

FIG. 9 is a right-hand view of the double sheet sensing device;

FIG. 10 is a sectional view of FIG. 6;

FIG. 11 is an enlarged view with parts broken away of the sheet reject mechanism and the sheet registration mechanism of the paper transport assembly;

FIG. 12 is a rear view of the paper reject mechanism and the sheet registration mechanism. of the paper transport assembly;

FIG. 13 is a top view with the xerographic drum removed;

FIG. 14 is a top view of a transport drive assembly and a switch actuator mechanism;

FIG. 15 is a top view of a second transport drive mechanism; and,

FIGS. 16 and 17 are a schematic electrical wiring diagram of the electrical components of the xerographic apparatus.

As shown schematically in FIG. 1, the automatic xerographic reproducing apparatus comprises a xerographic plate 20 including a photoconductive layer or light-re- 3,24%,486 Patented Mar. 15, 1966 ice ceiving surface on a conductive backing and formed in the shape of a drum, which is mounted on a shaft journaled in a frame to rotate in the direction indicated by the arrow to cause the drum surface sequentially to pass a plurality of xerographic processing stations.

For the purpose of the present disclosure, the several xerographic processing stations in the path of movement of the drum surface may be described functionally, as follows:

A charging station, at which a uniform electrostatic charge is deposited on the photoconductive layer of the xerographic drum;

An exposure station, at which a light or radiation pattern of copy to be reproduced is projected Onto the drum surface to dissipate the drum charge in the exposed areas thereof and thereby form a latent electrostatic image of the copy to be reproduced;

A developing station, at which a Xerographic developing material including toner particles having an electrostatic charge opposite to that of the electrostatic latent image are cascaded over the drum surface, whereby the tone particles adhere to the electrostatic latent image to form a xerographic powdered image in the configuration of the copy being reproduced;

A transfer station, at which the xerographic powder image is electrostatically transferred from the drum surface to a transfer material or a support surface; and,

A drum cleaning and discharge station, at which the drum surface is brushed to remove residual toner particles remaining thereon after image transfer, and at which the drum surface is exposed to a relatively bright light source to eflFect substantially complete discharge of any residual electrostatic charge remaining thereon.

The charging station is preferably located, as indicated by reference character A. As shown, the charging arrangement includes a corona charging device 21 which in cludes a corona discharge array of one or more corona discharge electrodes that extend transversely across the drum surface and are energized from a high potential source and are substantially closed within a shielding member.

Next subsequent thereto in the path of motion of the xerographic drum is an exposure station B. An optical scanning or projection system is provided to project a flowing image onto the surface of the photoconductive drum from a stationary original.

The sheet feeding mechanism includes a sheet feed device adapted by means of vacuum feeders to feed the top sheet, of a stack of sheets on a tray 41, to a set of feed rollers 42 for advancement by the feed rollers of the sheet to a paper transport 44 which, in turn, conveys the sheet to a sheet registration device 45 positioned adjacent to the xerographic drum. The sheet registration device arrests and aligns each individual sheet of material and then in timed relation to the movement of the xerographic drum, advances the sheet material into contact with the xerographic drum in registration with a previously formed xerographic powder image on the drum.

The transfer of the xerographic powder image from the drum surface to the sheets of support material is effected by means of a corona transfer device 51 that is located at/ or immediately after the line of contact between the support material and the rotating drum. In operation, the electrostatic field created by the corona transfer device is effective to tack the support material electrostatically to the drum surface, whereby the support material moves synchronously with the drum while in contact therewith. Simultaneously with the tacking action, the electrostatic field is eifective to attract the toner particles comprising the xerographic powder image from the drum surface and cause them to adhere electrostatically to the surface of the support material.

Immediate subsequent to the image transfer station, there is positioned a stripping apparatus or paper pick-off mechanism 52 for removing the sheets of support material from the drum surface. This device, which is of the type disclosed in Rutkus et al. Patent 3,062,536, includes a plurality of small diameter orifices supplied with pressurized aeriform fluid by a suitable pulsator or other device. The pulsator is adapted to force jets of pressurized aeriform fluid through the outlet orifices into contact with the surface of the xerographic drum slightly in advance of the sheet of support material to strip the leading edge of the sheet from the drum surface and to direct it onto an endless conveyor 55 whereby the sheet material is carried to a fixing device 60. At the fixing device, the transferred xerographic powder image on the sheet of support material lS permanently fixed or fused thereto as by heat. After fusing, the finished copy is discharged from the apparatus at a suitable point for collection externally of the apparatus by means of the conveyor 65.

Paper transport Paper separated and fed by the sheet feed mechanism 40 is further advanced by a paper transport 44, constructed in accordance with the invention, to a sheet registration device 45 whereat the leading edge of a sheet is aligned and then advanced to the xerographic drum in registration with a previously developed image there-on. Transfer of the developed image on the drum to the sheet of paper is affected electrostatically by corona transfer device 51. After transfer, the sheet is separated from the drum-by sheet pick-off device 52, the sheet dropping onto endless conveyor 55 to be forwarded thereby to fuser 60.

In the embodiment of the xerographic apparatus shown, paper transport 44, sheet registration device 45, corona transfer device 51 and endless conveyor 55 are supported on a frame assembly formed as a separate unit from the main frame of the machine. The frame assembly supporting these elements may be moved as a unit away from the xerographic drum to permit access to the paper path.

As shown, the frame assembly includes an outboard frame 501 and an inboard frame 502 held in rigid spaced relation to each other by tie bars 503 which also support one portion of drawer slides 504, the mating portions of which are secured to angle rail supports 505 fastened to the base plate of the main machine frame.

The paper transport 44 includes a transport frame having a guide plate 510 and depending side plates 511 and 512 to support the remaining components of the paper transport.

The side plates 511 and 512 of paper transport 44 are secured to outboard frame 501 and inboard frame 502, respectively, by angle brackets 513, secured to the side plates as by welding, and by screws 514 to the frames.

A plurality of endless belts 521 are looped about an idler roller 522 and a drive roller 523. Idler roller 522 is journaled in bearings 524 positioned in bearing brackets 525 secured to side plates 511 and 512. Drive roller 523 is journaled in bearings 526 retained by the recessed apertur-ed portions of side plates 511 and 512 and held in axial alignment by collars 527. The drive roller is driven by chain 530 engaging sprocket 528 fixed to the inboard end of the drive roller.

The sheets are held in engagement with the belts by ball weights 531 carried in ball retainer brackets 532 and 533 secured to ball carrier bracket 534 supported by spacers 535 and 536 secured to side plates 511 and 512 whereby the ball weights will be in contact with the belts 521 or with a sheet therebetween.

In addition, a paper guide 519 is secured on spacers 536 to prevent the leading edge of a sheet from being deflected as it strikes the actuator of count limit switch 8LS. Limit switch 8L5 is mounted below guide plate 510 with its actuator extending through a suitable slot in the guide plate into the path of travel of a sheet.

To insure alignment of the right hand edge of a sheet, as seen in FIG. 6, against the inboard end of guide plate 510, an edge guide 515 is adjustably secured to the underside of the guide plate by slide plate 516 fastened to guide plate 510 to effect proper side registration by jagging each sheet approximately one-eighth inch. As shown in FIG. 10 one end of leaf spring 517 is secured to the underside of guide plate 516, the free end of the spring being provided with an aperture to receive ball detent 518 adapted to engage suitably spaced apertures in the edge guide whereby the edge guide can be adjusted for various size sheets.

To prevent delivery of multiple or superposed sheets, a multiple sheet sen-singdevice is used to sense the presence of superposed sheets and thereby control the operation of a diverter to discharge these superposed sheets rather than allowing them to be transported to the drum.

The sheet sensing device includes an adapter arm 541 supported at one end on spacer 536 and at its other end on a spacer rod 537. The adapter arm 541 is adjustable about the axis of spacer 536 whereby the opposite end of the adapter arm can be positioned at a predetermined height or functional setting above one idler roller 522. Adjustment of the height of the adapter arm is effected by screws 542 and 545 threaded in the bifurcated ends of the adapter arm into contact with the spacer 537.

When the adapter arm is correctly positioned, screws 542 are locked into position by nut 543 and then the screw 544 threaded into the opposite end of this arm, is used to lock the adapter arm to spacer 536.

A multi-feed sensing limit switch 9L8 is mounted on switch bracket 551 secured to adapter arm 541, with the actuator of the limit switch positioned to be actuated by the free end of a pivot arm 546.

The pivot arm 546 is pivotally secured at one end by pin 547 to the adapter arm. Sheet sensing roller 548 is journaled to pivot arm to contact limit switch 9L8 before its actuator can be moved sufliciently to damage this switch.

The adapter arm is positioned, as previously described, to permit contact between the sensing roller and a single sheet as it is advanced by the belts without causing the operation of the limit switch 9L8, a normally open switch. However, when more than a single sheet passes between the idler roller 522 and the sensing roller, the sensing roller will rise to allow the multiple or superposed sheets to pass and thereby rock the pivot arm sufficiently to actuate the limit switch 9L5 to a closed position, for a purpose to be described.

As previously described, the multiple sheet detecting device is used to effect operation of a sheet diverter, which in the apparatus shown, forms part of a sheet registration device, generally identified by reference character 45.

In the normal operation of the sheet feed system, that is, when a single sheet has been separated from the stack and fed to the paper transport, the sheet is advanced toward the drum by the paper transport 44. Single sheet thus advanced are guided by feed table 580 toward an other set of feed rollers 601 and 602 which will direct the sheet into contact with the peripheral surface of the xerographic drum. Before the sheet can be advanced into the bite of the feed rollers 601 and 602 its forward progress is stopped by a register stop 561 positioned in front of these feed rollers in the normal paper path.

The register stop 561 is used to align the leading edge of the sheet parallel to the axis of the drum and to restrain the forward progress of the sheet for a short period of time so that the final advancement of the sheet to the drum is timed for proper registration with a developed xerographic image previously formed on the drum.

The register stop 561 is provided at opposite ends with pins 562 journaled in suitable bearings mounted in inboard end outboard frames 502 and 501, respectively.

The inboard end of the register stop has a depending portion to which is secured a spring bracket 563 and a cam follower 564. Cam follower 564 is forced into engagement with a cam 571 by means of spring 565 connected at one end to spring bracket 563 and at its opposite end to pin 566 secured to inboard frame 502.

The cam 571 is fixed to shaft 572 suitably journaled in outboard frame 501 and inboard frame 502. This shaft is rotated by means to be described at a speed directly related to the drum speed, which speed is also related to the speed of scanning of an image for projection onto the drum. The register stop is pivoted out of interference relation to a sheet to allow the sheet to be advanced to the drum at a predetermined interval after start of scanning as controlled by the fall of the scan cam and its rate of rotation with respect to the drum.

As shown, shaft 572 is journaled in bearings 5'78 and 574 mounted in inboard and outboard frames 502 and 501, respectively. A spacer 575 encircles shaft 572 between cam 571 and inboard frame 502, and a sprocket 576 and clutch cam 577 are secured to this end of the shaft.

Referring again to the table feed, generally designated 580, it includes a paper guide portion 581 and a reject gate portion 582 formed integral with each other, and a depending bifurcated portion 583 to slidably receive the grooved pin 586 of actuator lever 587 secured to one end of stub shaft 588. The feed table is pivotally mounted by pins 584 extending therefrom journaled in suitable bearings mounted in the inboard and outboard frame plates.

Stub shaft 588 journaled in outboard frame 501, has one end of lever 591 secured thereon, the opposite end of the lever being secured by pin 592 to the plunger of solenoid SOL2 supported by bracket 593 to the outboard frame. Solenoid SOL-2 is suitably connected in an electrical circuit to limit switch 9L5. When the solenoid SOL-2 is energized by closure of limit switch 9LS because of the sensing of superposed sheets, will retract its plunger causing lever 591 and therefor actuator lever 587 to rotate clockwise, as seen in FIG. 11, thereby causing the feed table 580 to rotate in the opposite direction bringing the reject gate portion into the path of paper travel to deflect the paper downward against paper defectors 594 and 595 which guide the paper into a paper catch tray S96.

Lever 591 is normally biased in a counterclockwise direction by torsion spring 589 encircling stub shaft 588. One end of the torsion spring is connected to pin 566 in frame 501 and the other end is secured to lever 591.

In the normal operation of single sheet feeding, the forward progress of a sheet is stopped for a very short period of time by the register stop 561, but as this register stop is suddenly lowered out of the path of paper travel, the sheet is advanced to the feed rolls 601 and 602 which firmly feed the sheet between guides 611 and 612 into contact with the drum adjacent corona transfer unit 51.

The feed rolls 601 and 602 are also driven in timed relation with the peripheral speed of the drum. As shown, feed roll 601 is journaled in frames 501 and 502 and is driven by sprocket 603.

Sprocket 603 on the feed roll 601 and sprocket 528 on driven roller 523 of the paper transport are operatively connected by chain 530 to sprocket 576 on shaft 572.

As a sheet is forwarded between guides, the sheet will contact the actuator of a limit switch 1L8 suitably supported beneath guide 612.

After transfer, the leading edge of the sheet is separated from the drum by the sheet pick-off mechanism 52, the remainder of the sheet then peeling off the drum due to its own weight to fall onto the belts of endless conveyor 55 which transport the sheet to heat fuser 60.

Endless conveyor 55 includes a transverse extending guide plate 621 secured by angle brackets 626 to frames 501 and 502; a flanged cover 624 is secured as by cam welding to the underside of guide plate 621 forming therewith a vacuum manifold having a number of inlet apertures 622 formed in the guide plate and a discharge connection 623 in communication with a suitable aperture in inboard frame 502 which is connected by vacuum connector 507 and by flexible conduit 625 to a vacuum pump. Suitable gaskets 506 are provided between guide plate 621 and frame 502 and between frame 502 and vacuum connector 507.

Sheets pulled toward the guide plate by suction through inlet apertures 622 are carried by belts 629 looped over idler roller 627 and driven roller 628 suitably journaled in the depending portions of guide plate 621. Driven roller 628 has a cam 629 fixed thereon to be driven in a manner to be described.

A miss detector limit switch 3LS is secured by a suitable bracket in a position whereby the actuator of the limit switch extends through an aperture in guide plate 621 into the path of paper travel, for a purpose to be described.

As previously described, the frame assembly, carrying paper transport 44 sheet registration device 45, corona transfer device 51 and endless conveyor 55, is slidably mounted by means of drawer slides 504.

To insure proper alignment of these components with the xerographic drum, the brackets 641, secured to base plate 10, are provided with locating pins 542, adapted to engage suitable locating aperatures formed in the frame 502.

The outboard frame 501 is aligned vertically by means of bearing plates 645 fixed to this frame and which are adapted to slide onto the locating plates 646 secured to base plate 10 in position to engage the bearing plates as this assembly is pushed parallel to the drum.

Complete withdrawal of this assembly is prevented by suitable stops positioned on the drawer slides 504.

In this position of the assembly, the operator can remove the superposed sheets ejected into catch tray 596. The catch tray, as shown in FIG. 7, is pivotally secured by hinge 651 to a tray support 652 secured to frames 501 and 502, whereby as the assembly is advanced over the edge of base plate 10, the feed out tray will pivot down about hinge 651. As this assembly is again returned to operative relation with respect to the drum, the catch tray is cammed back into sheet receiving position by the cam action of spring support 652, secured to the underside of the catch tray, as it contacts base plate 10.

This entire assembly is locked into operative relation with the xerographic drum by manual operation of lever arm 661. Lever arm 661 is fixed to one end of shaft 664 journaled by bearings 662 and 663 positioned in base plate 10, a cam follower 665 being secured to the opposite end of the shaft to engage cam 666 secured to outboard frame 501. With the lever arm 661 in the position, as shown in FIG. 4, the assembly is properly located in operative position by engagement of cam follower 665 with cam 666. The lever arm, is locked in this position by engagement of ball detent 668 with the knob 667 fixed to the opposite end of lever arm 661 from shaft 664. Ball detent 668 is supported by detent holder 671 threaded into base plate 10 and is biased into engagement with knob 667 by spring 672 positioned within the recessed portion of detent holder 671.

Machine drive As previously described, the xerographic drum 20, and the object trnirr-or during the scanning cycles are driven in synchronization with each other by means of a main drive motor M-3. Since the movement of a copy sheet, such as paper, to and from the drum must also be synchronized with the peripheral surface speed of the drum, the paper transport 44 and elements associated therewith, endless conveyor 55, fu'ser or fixing device 60 and inclined conveyor 65 are also driven by main drive motor M-3.

As shown'schematically in FIG; 3, each of these components is operatively connected to the sprocket 133 driven -by the main drive motor which also drives the drum as previously described. These components are operatively connected to sprocket 133 by chain 701 extending from sprocket 133 over an idler sprocket 702 around sprocket 703 to sprocket 704 then around a sprocket 821 to drive the heat fuser 60, around a sprocket 705 to drive inclined conveyor 65, over an idler sprocket 706 then into engagement with idler sprockets 707 and 708back up to sprocket 133. Idler sprockets 702 and 706 are adjustably secured to inboard frame 12, while idler sprockets 707 and 708 are fixed collar sprockets.

As shown in FIG. 14, sprocket 703 is fixed as by brazing to a hollow splined shaft 711 journaled by bearings 712 in a switch-mounting housing 713 secured to inboard frame 12.. A splined shaft 714 is loosely supported in hollowsplined shaft 711 for rotation therewith and for movement therein. vAxial movement of the shaft 714 within the splined shaft 711 is limited by means of a dowel pin 715 extending radially from one end of the shaft 714 to be slideably received by the elongated slot 716 formed in the splined shaft 711. The opposite end of shaft 714 has a single lobe cam 717 secured thereon, the cam 717 being adapted to drivingly engage cam 577 on shaft 572, to thereby drive the paper transport 44 and feed roll 601 through the chain drive, previously described. The cam 717 is normally biased into driving engagement with cam 577 by the biasing action of a spring 718 positioned within the hollow splined shaft 711. One end of the spring contacts the axially movable shaft 714, the opposite end of the spring abutting against a splined cam shaft 721 fixed to hollow splined shaft 711 by pin 722. With this arrangement, there is provided a releasable clutch drive for a portion of the paper transport assembly which normally maintains timed relation of shaft 572 to the xero-graphic drum and also to permit withdrawal of the paper transport assembly as previously described.

The splined cam shaft 721 has fixed thereon five cams 723, 724, 725, 726, and 727, for actuating five limit switches suitably positioned within the switch-mounting housing. Cam 723 is used to actuate a miss-puff pulse limit switch ZLS, cam 724 actuates a paper feed limit switch 5LS, cam 725 actuates a count pulse limit switch 7LS, cam 726 actuates a reject break circuit limit switch 10LS and cam 727 actuates a puffer limit switch IZLS. Each of these limit switches is actuated in timed relation to the rotation of the xerographic drum through the drive mechanism, just described.

In a similar manner, sprocket 704 is fixed to a hollow splined shaft 731, journaled by bearings 712 positioned in bearing housing 730 fixed to inboard frame 12. A splined shaft 732, carrying a cam 733 adapted to engage cam 631 fixed to drive roll 628 of the endless conveyor 55, is loosely supported in the hollow splined shaft 731 for rotation therewith and for axial movement therein. Axial movement of shaft 732 within the hollow splined shaft 731 is also limited by means of a dowel pin 715 extending radially from the shaft 732 to be slideably received by the elongated slot 734 formed in the hollow splined shaft 731. The cam 733 is normally biased into driving engagement with cam 631, when the paper transport assembly is in its operative position in relation to the xerographic drum by means of spring 735 positioned in the hollow splined shaft 731; Spring 735 abuts at one end against a shaft 736 fixed as by pin 722 to the hollow splined shaft 731, and at its other end, abuts the splined shaft 732.

With this arrangement of the drives, the scanning mechanism, and the paper feed system for advancing the sheet of support material to and from the drum are affected in synchronization with the rotation of the drum through a common drive medium, that is, motor MOT-3.

Assuming that only a single sheet has been advanced by the sheet feed device 40, the cam actuated count pulse limit switch 7LS will be actuated to complete a circuit through the normally closed contact 6LSB of no count switch 6L8 and by momentarily closed count switch 8L8 to energize counter 3TR connected in parallel with a billing counter M1. As the paper is continued to be fed, it will actuate limit switch 1LS. As the paper continues to advance, it will contact the xerographic drum and as it passes adjacent to the corona transfer device 51, the paper will adhere to the xerographic drum electrostatically and would continue to rotate with the drum unless it is removed by the paper pick-oif mechanism 52. The operation of the pick-off device is effected by a solenoid SOL-3 operated valve controlled by a puffer limit switch 12LS which is actuated at this time.

After the sheet is puffed off the drum, the sheet will be advanced by endless conveyor and as the sheet is advanced, it will actuate a miss-detector limit switch 3L8. The miss-detector limit switch 3LS is a normally closed switch and this switch, as it is actuated by the sheet, will open the circuit through transformer T-11 to the rnisspuff indicator lamps LMP-12 and LMP-13 being closed due to the closing of miss-puff pulse switch 2LS at this same time, it being noted that the trailing portion of the sheet would be still in contact with the actuator of limit switch 115 at this time to close this switch. Miss-detector switch 3LS opening at this time prevents control relay 2CR from being energized to shut down the machine operation, it would happen if a sheet were not puffed oif the surface of a xerographic drum. A normal pufling of the sheet from the drum will prevent machine shut-down.

A sheet carried by endless conveyor 55 will be advanced to the fuser and then onto inclined conveyor for discharge from the machine. It is noted that when the print switch SW-4 was placed to initiate a reproducing cycle, control relay 4CR was energized to open its normally closed contact 4CR-2 thereby breaking the circuit to control relay 3CR, thereby tie-energizing this control relay to put the fuser on high heat through the normally closed contact 3CR-2.

Referring again to the counter 3TR, this counter is used to control the number of reproductions to be reproduced. A suitable programmer mechanism, not shown except schematically on the electrical wiring diagram,-is positioned on the cabinet, not shown, enclosing the xerographic apparatus. With this programmer, the operator may select the number of reproductions to be made through the use of selecting switches in the control panel. Assuming that the operator has set the programmer to make three reproductions, the contact SW-7D of unit switch SW-7 is depressed by the operator. Unit switch SW-7 is used in selecting units of one through nine, inclusive, and switch SW-6 is used in selecting the number of reproductions in units of tens. With these selecting switches, the operator may select any number of reproductions to be reproduced from one through 99, inclusive.

Referring again to the mode operation of this program: mer mechanism when making three reproductions, as each sheet onto which the document is reproduced is advanced, the count pulse switch 7LS is actuated to step the contact 3TR-2 of the counter until the third sheet actuating this count switch advances the contact 3TR-2 into contact with contact SW-7D, which completes a circuit through contact 3TR-1 and a closed contact SW-6B of switch SW-6. It is noted that contact 3TR-1 would also advance in a similar manner if more than nine reproductions were selected to be made.

As this circuit is completed, control relay 7CR is energized closing its contact 7CR-2A., which maintains 7CR energized. At the same time, that counter relay 7CR is energized, the motor driven timer ZTR is energized.

Timer 2TR is a motor driven timer which operates cam driven switches. Switch ZTR-4 is the first switch to be actuated by the cam. Switch ZTR-4 which is open approximately /2 second after timer 2TR is energized, shuts off the document lamps. Switch 2TR-3 is actuated approximately 2 /2 seconds after ZTR is energized to deenergize the motor MOT- which operates the developer apparatus 30 in the sheet feed device 40. Switch 2TR-2 is actuated approximately 5 /2 seconds after ZTR is energized and this switch opening shuts off motor MOT2 used to rotate the cleaning brush of the cleaning device 70. Switch 2TR-1 is adjusted to operate when the last copy or sheet has just left the exit of the machine as conveyed by inclined conveyor 65. This time interval is approximately 8 /z seconds after ZTR is energized.

After the last sheet has left the machine, switch ZTR-l opens and this breaks the circuit to control relay 4CR. As 4CR is de-energized, its contact 4CR1 opens and contact 4CR-3 opens which opens the power circuit to all the components that were energized in the start of the print cycle, as previously described. At this time, control relay 3CR is again energized through the now normally closed contact 4CR-2 to again put the fuser on standby operation. It is noted that when control relay 7CR was energized, its contact 7CR-1A was closed to energize the ready lamps LMP-16, LMP-17, LMP-18 and LMP-19 to indicate to the operator that the machine had completed the programmer reproductions and was now ready for a new reproducing cycle of the document now on the platen or of a second document placed on the platen at this time. The programmer with its selector switches is a dual purpose counter that not only initiates the machine shut-down cycle after a pre-determined number of copies is made, but it also gives a visual read-out to the operator indicating the number of the reproductions the machine is in the process of making at any time, this also being programmed electrically.

As previously described, the major components efi'ecting reproduction of a document are closed down at ap proximately 8% seconds after the counter ZTR is energized. This is the normal shut-down operation of the machine.

If it is desired to stop the feeding of paper and to shut down the machine before the machine has completed making the pre-selected number of reproductions, this can be effected by depressing the button controlling the print-stop switch SW-S. As this switch SW5 is closed, it completes a circuit to again energize control relay 7CR, which then holds through its own contact 7CR2A in parallel with ZTR, to thereby energize timer 2TR to effect a normal machine shut-down cycle, as previously described. This will permit any sheets fed by the sheet feeding device to be transported from the machine before the components are de-energized.

In the event the operator reloads or places a new document on the platen before the machine has completed the shutdown cycle, the operator may depress the print switch SW4 any time after the ready lights, lamps LMP-16, LMP17, LMP-18 and LMP-19 have come on. By depressing the print switch SW-4, its contact SW-4C is opened thereby opening the circuit to control relay 7CR and to the timer 2TR which automatically resets. The machine will now start a new reproducing cycle in the normal sequence of operation as previously described.

The only time this will not or cannot happen is if the operator is able to load the document and then depress this switch SW-4 before the contact 2TR-3 is actuated, approximately 2 /2 seconds after the start of the previous shut-down cycle. In the event the print switch SW-4 is depressed before the lapse of this 2 /2 second time interval, the machine will simply ignore the command of the print switch SW-4. This is effected through control relay SCR actuated during the previous print cycle. The contact SCR-Z being in parallel with the switch SW-4C prevents dropping out of the counter relay 7CR and timer 2TR. Also counter relay SCR will prevent the counter from resetting before the 2 /2 second time interval.

In the event that a double sheet is fed instead of a single sheet by the sheet feed device 40, the multiple sheet sensing switch 9L5 will be actuated by the previously described multiple sheet detecting device, which senses the thickness of more than one sheet advanced by sheet feed device 40 to paper transport 44. As limit switch 9L8 is closed, it will through reject limit switch 10LS, which is timed to be closed at this time, close a circuit to solenoid SOL-2.

As solenoid SOL-2 is energized, its plunger will contact the actuator of no count limit switch 6L8 to close its contact 6LSA to lock in the circuit to solenoid SOL-2. In addition, normally closed contact 6LSB is opened to prevent counting, by opening the billing counter M-1 and the counter 3TR circuits. In addition, the plunger of solenoid SOL2 is linked mechanically to a reject gate, previously described, to deflect the superimposed sheets from the normal paper path thereby ejecting these sheets into the catch tray. Operation of the reject switch IOLS is so timed that it will open again before the following sheet advanced by the sheet feed device 40 arrives at the multiple sheet sensing device on paper transport 44.

To provide for machine shut down, in the event of a miss-puff, the sheet which is advanced into contact with the Xerograp'hic drum has actuated register switch 1LS. Since this sheet is a miss-puff, it is not puffed down onto endless conveyor 55 to actuate miss-detector switch 3L8, which normally would be actuated by a sheet puffed from a xerographic drum.

Operation of miss-puif pulse switch 2L8 is time set so that at this moment, slightly after SLS should have been actuated to break the circuit, 2L5 will be closed to complete the circuit to control relay ZCR. Control relay ZCR is energized and is held energized through its own contact 2CR2, and through the normally closed reset switch SW3.

Actuating control relay ZCR opens the circuit to control relay ICR thereby dropping out the machine ON circuit. Contacts 1CR2 and 1CR3 of control lCR are opened to open the circuit to all the machine elements except the holding circuit on control relay ZCR. When this happens, the machine will stop immediately.

Before the machine can again be energized, the operator must remove the miss-puffed sheet adhering to the drum from the machine. Then, the operator can push the reset switch SW3 to open the circuit just described and then the operator can again start the machine by depressing start switch SW-l. The machine will then require some length of time before the print switch SW-4 can be depressed to start a new print cycle. When a misspuff occurs, the lamps LMP12 and LMP-13 are energized by transformer T-ll thereby notify-ing the operator of the miss-puff.

There is provided a low paper indicator switch 4LS positioned to be actuated when the supply of paper in the sheet feed device 40 is exhausted. When this low paper indicator switch 4L8 is actuated, its contact 4LS-1A is closed to supply power through transformer T-12 to the low paper indicator lamps LMP-14 and LMP-lS. The contact -LS-l B is also opened at this time to prevent the operator from starting another print cycle through the depressing of print switch SW-4. In addition, the contact 4LS-2 will be closed to energize control relay 7CR and the relay ZTR to effect a print shut-down cycle so that the machine will not be operated for a long period of time with no paper, in the event that the machine has previously been programmed to make a large number of reproductions when in the multi-copy made only. While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the appended claim.

What is claimed is:

A sheet transport device including a frame,

a pair of rolls journaled in said frame in spaced relation to each other,

endless belts carried by said rolls parallel to said frame and driven thereby,

bracket means secured to said frame and positioned above the upper surface of said belts,

a plurality of balls rotatably supported by said bracket in position to contact the upper surface of one of said belts or a sheet of material passing thereunder,

a slide bracket secured to said frame,

a sheet guide adjustably positioned in said slide bracket,

said sheet guide having a guide portion extending into path of sheet travel as carried by said endless conveyor belts,

said guide portion having a turned portion at an angle less than perpendicular to the plane of the endless conveyor belts, and

12 said guide portion being positioned at an angle to the path of sheet travel to cam a miss-aligned sheet against an edge of said frame opposite from said sheet guide to align a sheet thereagainst.

References Cited by the Examiner UNITED STATES PATENTS ROBERT B. REEVES, Primary Examiner.

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