Abstract:
Printers such as electrophotographic printers are provided with multipaths for facilitating different kinds of printing operations (simplex, duplex). The multipaths are utilized through use of a sheet diverter and a sheet pickup mechanism.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention generally relates to office machine printers such as electrophotographic printers, ink-jet printers, etc. More particularly, it relates to apparatus and techniques for improving the utility of such printers by providing an expanded array of print media paths therein.  
           [0003]    2. Prior Art  
           [0004]    Office machine printers such as electrophotographic printers, inkjet printers, etc. very often have both a simplex printing path and a duplex printing path. In the case of simplex printing, a sheet is first taken from a stack of print media (such as a stack of paper) that resides in a sheet dispenser tray located next to, or forming a part of, a printer housing. It is then guided into a first opening in said housing. The sheet receives printing on one side and thereafter leaves the printer as a finished product via a second opening in the printer housing. This second opening is usually serviced by a sheet collection tray.  
           [0005]    In the case of duplex printing, a sheet that has received printing on one side is then: (1) temporarily stored in a duplexing tray (that normally resides completely within the printer housing), (2) withdrawn from the duplexing tray, (3) turned over within the printer housing, (4) subjected to printing on its second side and then (5) sent to the sheet collection tray via the same second opening used in the simplex printing operation.  
           [0006]    Thus, for example, an electrophotographic printing process might generally comprise the steps of ( 1 ) withdrawing a sheet of paper from a stack of such paper residing in a sheet dispenser tray, (2) placing said sheet in a print media path in the printer, (3) using a light emitting source such as a laser beam to form an electrical latent image on a charged photoconductor drum, (4) developing that latent image with a toner, (5) transferring the resultant toner image onto the sheet of paper, (6) fusing the toner image to the sheet (by means of heat, pressure, etc.) and then (7) sending that sheet directly to the sheet collection tray (simplex printing), or (8) sending the sheet to a duplexing tray (duplex printing) located within the printer, (9) removing the sheet from the duplexing tray, (10) turning the sheet over, (11) printing on its second side, (12) directing said sheet through a fuser and then (13) sending said sheet to the sheet collection tray.  
         SUMMARY OF THE INVENTION  
         [0007]    This invention is concerned with printers having a plurality of print media paths. A plurality of print media paths enables a printer to carry out simplex and/or duplex printing operations. In the printers of this patent disclosure, a first print media path carries a given sheet of print media from a sheet pickup mechanism to a printer device (e.g., to an electrophotographic printer, to an inkjet printer, etc.). A second print media path carries the sheet from the printer device to a sheet exit opening. A third print media path carries a given sheet back through the sheet exit opening and then to the printer device as part of a duplex printing operation.  
           [0008]    A housing for applicant&#39;s printer has (1) at least one sheet entry opening through which a sheet can be delivered to the first print media path and (2) at least one sheet exit opening through which the sheet can be (a) dispensed from the housing after said sheet travels, in a first flow direction, past the printer device and past a sheet diverter, (b) pulled, in a second flow direction, back through the sheet exit opening so that it can be sent back to the printer device as part of a duplex printing operation.  
           [0009]    Applicant&#39;s printer also has a sheet diverter and a sheet pickup mechanism. The sheet diverter has a first operating position for allowing a sheet to pass, in the first flow direction, and a second operating position for diverting a given sheet, while said sheet travels in a second flow direction, back toward the printer device as part of a duplex printing operation. In one embodiment of applicant&#39;s invention, the sheet path diverter operates from a first operating position when a sheet is moving past the diverter in a first flow direction (i.e., forward, toward the sheet exit opening) and operates from a second operating position when that same sheet is moving past the diverter in a second, backward flow direction leading back to the printer. The sheet pickup mechanism has a first operating position wherein said mechanism picks up a given sheet from a sheet dispensing tray, and a second operating position wherein said mechanism serves as a part of the third print media path that sends a sheet back to the printer as part of a duplex printing operation.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1( a ) is a cross section view of an embodiment of a printer having four print media entry and/or exit openings and wherein an individual sheet is shown being withdrawn from a sheet dispensing tray and delivered (via a first forwardly moving sheet transport path) to a printer mechanism.  
         [0011]    [0011]FIG. 1( b ) is a cross section view of the embodiment of the printer of FIG. 1( a ) wherein the sheet is shown passing through a fuser, over a sheet diverter (in a first operating position) and out of a sheet exit opening.  
         [0012]    [0012]FIG. 1( c ) is a perspective view of a sheet pickup/transport device in the form of a belt looped around two rollers.  
         [0013]    [0013]FIG. 1( d ) is a side view of the sheet pickup/transport device shown in FIG. 1( c ).  
         [0014]    [0014]FIG. 1( e ) is a perspective view of a multiple-roller device that also can be used as a sheet pickup/transport device in the practice of this invention.  
         [0015]    [0015]FIG. 2( a ) is a cross section view of the embodiment of the printer of FIG. 1( b ) wherein a sheet has reached a full forward position in the sheet exit opening.  
         [0016]    [0016]FIG. 2( b ) is a cross section view of the embodiment of the printer of FIG. 2( a ) wherein the sheet has moved in a backward direction, collided with a sheet directing surface of the sheet diverter (as a result of said diverter being in its second operating position) and directed into contact with a sheet pickup mechanism.  
         [0017]    [0017]FIG. 2( c ) depicts the embodiment of the printer of FIG. 2( b ) in an operating position wherein the sheet is passing over the sheet pickup mechanism and over a portion of the first forwardly moving sheet transport path leading from the sheet dispensing tray to the printer.  
         [0018]    [0018]FIG. 3( a ) shows an embodiment of a printer such as that depicted in FIG. 1( a ) wherein a sheet of print media has been introduced into said printer via a second sheet entry opening and is shown passing through the printer and fuser.  
         [0019]    [0019]FIG. 3( b ) shows the sheet depicted in FIG. 3( a ) passing over the diverter (in its first operating position) and exiting the printer via a sheet exit opening.  
         [0020]    [0020]FIG. 4( a ) is a cross section view of an embodiment of a printer such as the one depicted in FIG. 1( a ) wherein a sheet is shown entering the printer via a third sheet entry opening in the printer housing.  
         [0021]    [0021]FIG. 4( b ) shows the printer of FIG. 4( a ) wherein the sheet shown in FIG. 4( a ) is passing over the first forward moving sheet transport path of said printer that generally leads from the sheet dispenser tray to the printer.  
         [0022]    [0022]FIG. 4( c ) shows the printer of FIG. 4( b ) wherein the sheet is passing through the printer, fuser and out of the sheet exit opening.  
         [0023]    [0023]FIG. 5( a ) shows a cross section view of an embodiment of a printer provided with a second sheet dispensing tray from which a sheet is being taken and directed into the first forwardly moving sheet transport path.  
         [0024]    [0024]FIG. 5( b ) shows the embodiment of the printer of FIG. 5( a ) wherein the sheet is shown passing through the printer and fuser via the second forwardly moving sheet transport path.  
         [0025]    [0025]FIG. 5( c ) shows the embodiment of the printer of FIG. 5( b ) wherein the sheet is shown leaving the printer via the sheet exit opening.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    [0026]FIG. 1( a ) shows a cross section view of a multipath, electrophotographic printer  10  that is generally constructed according one embodiment of this invention. This particular electrophotographic printer  10  has an external housing  12  that has at least three and preferably four sheet entry and/or exit openings e.g., openings  14 ,  16 ,  18  and  20  through which sheets of print media can be introduced into, or taken from, the printer  10 . The printer  10  is shown provided with a sheet dispensing tray  22  in which a stack  24  of sheets of print media rests. A representative top sheet  26  of this stack  24  is shown being removed from said stack.  
         [0027]    This representative top sheet  26  (having a top surface  26 A and a bottom surface  26 B) is shown being guided over a first forwardly moving sheet transport path  28 A that forms a first part of an overall print media path through the printer  10 . This overall print media path is comprised of the first forwardly moving sheet transport path  28 A (i.e., the first part of the print media path) and a second forwardly moving sheet transport path  28 B (i.e., the second part of the print media path). The first part  28 A of the overall media path generally extends from the front of the stack of sheets  24  to a printer device  30  such as a photoconductor drum. The second part  28 B of the overall media path generally extends from the printer device  30 , to a fuser  32  and then to a sheet exit opening  16 . The exit opening can be serviced by a sheet collection tray. The first part  28 A of the overall media path also may be thought of as extending from the upper front region  36  of a representative top sheet  26  in the print media stack  24  to the printing device  30 , preferably via a first, powered, guide roller system  38 / 40 . Travel of a given top sheet  26  over this first part  28 A of the overall media path also can be facilitated by use of sheet transport and/or guide devices  42 ,  44 , etc. well known to the office machine printer arts. Generally speaking, such a sheet  26  travels upward from the upper front region  36  of a given top sheet  26  of print media to the guide roller system  38 / 40 . Thereafter, the sheet travels over the second part  28 B of the overall media path (i.e., over media paths  28 A and  28 B) in a generally forward direction (e.g., from left to right) through the fuser  32  and on toward sheet collection tray  34 .  
         [0028]    The electrophotographic printer  10  shown in FIG. 1( a ) is shown provided with a printer device  30 , e.g., in the form of a photoconductor drum upon which a latent electrostatic image is placed, and thereafter removed (by methods well known to the electrophotographic printing arts). For example, a charge roller  46  can be used to charge the surface of the photoconductor drum  30  to a predetermined voltage. A light-emitting device such as a laser scanner  48 , a LED array that emits a light beam  50  which is pulsed on and off as it is swept across the surface of the photoconductor drum  30  and thereby discharging select portions of the surface of the photoconductor drum  30  according to a computer program. The resulting selectively discharged portions of the surface of the photoconductor drum  30  constitute a latent electrostatic image. The drum  30  rotates (e.g., in the counterclockwise direction suggested by the arrow) into a rolling relationship with a developer roller.  
         [0029]    In the case of an electrophotographic printer, such a developer roller  52  is used to develop the latent electrostatic image in those places where the surface of the photoconductor drum  30  has been selectively discharged by the laser beam scanner  48 . In order to do this, charged toner particles having magnetic properties, stored in an electrophotographic toner print cartridge  54 , are moved from said cartridge to the developer roller  52 . For example, a magnet (not shown) located within the developer roller  52  can be used to magnetically attract charged toner particles to the surface of said developer roller. As the developer roller  52  rotates, the charged toner particles on the surface of the developer roller  52  are electrostatically drawn across a gap between the developer roller and the surface of the photoconductor drum  30  and thereby developing the latent electrostatic image in those areas of the drum  30  that were not discharged by the laser scanner  48 . This developed image is then ready to be transferred to a print medium such as a sheet of paper.  
         [0030]    In order to accomplish such a drum  30  to print medium  26  toner transfer, a given sheet of print media passes between a toner transfer roller  56  and the photoconductor drum  30 . Thus, a vertical region (not shown) between the bottom of the drum  30  and the top of the transfer roller  56  may be regarded as a vertical, toner transfer zone. The transfer roller  56  electrostatically attracts toner particles away from the photoconductor drum  30  and onto the top surface  26 A of the sheet of print media  26 . In a simplex printing operation, the bottom surface  26 B of the sheet  26  does not receive printing. Upon completion of such a simplex printing operation, the sheet is sent through the fuser  32  and then to the sheet collection tray  34  via the sheet exit opening  16 .  
         [0031]    Individual top sheets  26  of the print media are successively unloaded from the print media dispensing tray  22  by a sheet pickup mechanism  58 . This sheet pickup mechanism  58  has two operating positions or modes. In its first operating position or mode, this sheet pickup mechanism removes successive “top” sheets  26  from a stack  24  of sheets in the sheet dispensing tray  22  (e.g., by driving successive top sheets into the first portion  28 A of the print media path). In its second operating position, the sheet pickup mechanism  58  serves as a part of a print media path over which successive sheets travel in a duplex printing operation hereinafter more fully described.  
         [0032]    Such a sheet pickup mechanism  58  can be comprised of an endless belt  58 A that loops over a front roller  58 B and over a rear roller  58 C. One of these rollers is powered. Thus the powered roller (e.g., roller  58 C) drives the belt  58 A which turns the unpowered roller (e.g., roller  58 B). In the sheet pickup mechanism&#39;s first operating position, the axle of the front roller  58 B is lowered to a lower level  88  so that the belt  58 A will come into contact with successive top sheets  26  in the stack  24  of print media. In this first operating position, the rear roller  58 C is powered in the clockwise direction suggested by direction arrow  57 . By this action, the sheet pickup device  58  drives a given top sheet  26  forward (i.e., leftward) and into the first part  28 A of the overall media path. This overall media path may be further defined within the electrophotographic printer  10  by an array of media transporting, handling and guiding devices such as plate guides, powered rollers, belts, and the like. Again, by way of example only, FIG. 1( a ) shows the first part of the media path  28 A provided with a first guide plate  42  and a second guide plate  44  which serve to guide a given sheet into the first powered guide roller system  38 / 40 . It also should be noted in passing that the sheet  26  depicted in FIG. 1( a ) is bent a great deal (e.g., almost 90°) in traveling over the first part  28 A of the overall media path. Thus, a sheet  26  traveling over this first part  28 A should be a relatively flexible print material such as paper and flexible, plastic media such as overhead transparencies-as opposed to a relatively inflexible print media material such as cardboard and the like.  
         [0033]    After a given sheet of print media moves further along the media path (i.e., past the photoconductor drum  30  and the transfer roller  56 ), the second part  28 B of the overall media path delivers the sheet of print-carrying media to a pressure roller/fuser roller device  60 / 62 . The sheet of print media  26  passes between the fuser roller  62  and pressure roller  60  under conditions of both heat and pressure. Preferably, the pressure roller  60  provides a powered, pressured rolling interface relationship between the two rotating roller surfaces. For the sake of visual clarity and simplicity, this system is depicted as being only comprised of a pressure roller  60  and a heater or fuser roller  62 . By way of example, the pressure roller  60  is powered, and rolls against (and thereby drives) the heater roller  62 . Regardless of which roller is serving as a powered drive roller, the toner image-bearing sheet of print media passes through a rolling interface produced between the two rotating rollers. A heat source, such as an induction heater element or a halogen lamp, can be mounted in a hollow shaft of the fuser roller  62 . Thus, a combination of heat from the fuser roller  62  and pressure provided by the presence of the pressure roller  60  serve to fix given a toner image on a given sheet of print media.  
         [0034]    Thereafter, a first sheet output roller system  65  nips and pulls a sheet of print media further along the second part  28 B of the overall media path. This first sheet output roller system  65  is comprised of a top roller  66  turning in a counterclockwise manner and a bottom roller  68  turning in a clockwise manner. A second output roller system  67  (comprised of a top roller  70  and bottom roller  72 ) receives the rightwardly moving sheet and deposits it in a sheet collection tray  34 . While the sheet is moving from left to right the top roller  70  turns in a counterclockwise direction while the bottom roller turns in a clockwise direction. In a simplex printing operation, these output roller systems  65  and  67  serve to directly deliver a sheet to the sheet exit opening  16  and then to the sheet collection tray  34 . The sheet collection tray  34  is shown lying totally outside of the housing in FIG. 1( a ). The collection tray can be attached to the housing  12  of the printer  10  for correct positioning of said tray and easy manual access to any finished print product residing therein (e.g., a stack of paper  74 ).  
         [0035]    [0035]FIG. 1( b ) also depicts the electrophotographic printer of FIG. 1( a ) in its first operating position at a point where a representative sheet  26  is passing through (a) the fuser  32 , (b) the first sheet output roller system  65 , (c) the second sheet output roller system  67 , (d) the sheet exit opening  16  and on to the collection tray  34 . In this view the forward edge  78 A of the forward moving sheet  26  is shown being directed toward the collection tray  34  while the trailing edge  78 B is about to pass through the fuser  32 . This sheet  26  also can be regarded as passing over the second part  28 (B) of the overall print media path. Again, the sheet  26  is depicted as moving in a forward flow direction (i.e., moving from left to right). In so moving, the sheet  26  passes a sheet diverter  76  (e.g., the sheet  26  is shown passing over the top of the diverter without making any colliding contact with it). This sheet diverter  76  is very generally depicted as having a triangular configuration and a pivot device  76 A. The triangular configuration is, however, used primarily to illustrate the sheet flow aspects of this invention. For example, in FIG. 1( b ) the sheet  26  is shown moving in a forward direction (i.e., left to right) over a top surface of the diverter  76  while said diverter is in a first operating position. This first operating position is achieved by rotating the diverter  76  clockwise about its pivot device  76 A. FIG. 1( b ) shows that while the diverter  76  is in this first operating position, it offers little or no opposition to the forward (rightward) movement of a sheet  26  passing over it. Hence, the sheet  26  can be readily delivered (via sheet exit opening  16 ) to the sheet collection tray  34 . To a large extent, sheet  26  rests on top of the stack of sheets in the sheet collection tray  34 .  
         [0036]    [0036]FIG. 1( c ) is a perspective view of a representative sheet pickup/transport device  58  used in the multipath printers of this patent disclosure. The device  58  is comprised of a belt  58 A′ that is looped over two rollers  58 B and  58 C. The belt  58  is preferably made of an elastomeric material such as rubber, latex and the like. As seen in FIGS.  1 ( a ) and  1 ( b ) the sheet pickup/transport device  58  has two operating positions. In its second operating position, the device  58  has a substantially horizontal orientation such as that shown in FIG. 1( d ). While in this orientation a sheet can be transported (e.g., from right to left) by movement of the top surface  58 A′(T) of the belt  58 A′ (e.g., from right to left) by virtue of rotation of the rollers  58 B and  58 C in a counterclockwise direction.  
         [0037]    In its first operating position, the sheet pickup/transport device  58  has an inclined orientation such as that depicted by the phantom lines employed in FIG. 2( b ). That is to say that roller  58 B is at a level  88  that is lower than the level  86  of roller  58 C. This is the sheet pickup mode of operation of the device  58 . In this sheet pickup mode the rollers  58 B and  58 C are rotated in a clockwise direction so that the bottom surface  58 A′(B) of the belt  58 A′ is moved from right to left. Since the bottom surface  58 A′(B) of the belt  58 A′ also is in physical contact with a top sheet in the sheet stack  24 , the top sheet will be forced forward (i.e., from right to left).  
         [0038]    [0038]FIG. 1( e ) shows another sheet pickup/transport device  59  suitable for use in the practice of this invention. It is comprised of a series of rollers  59 A,  59 B . . .  59 E respectively rotatably mounted between two mounting bars  59 F and  59 G. Such a device  59  also has a second, horizontal operating position and a first inclined operating position. The rollers and especially powered outside roller(s)  59 A and/or  59 E also can be appropriately rotated in either a counterclockwise direction (to perform a sheet transport function) or a clockwise direction (to perform a sheet pickup function).  
         [0039]    [0039]FIG. 1( f ) is a cross section view of the multiple-roller sheet pickup/transport device  59  shown in FIG. 1( e ). By way of example, it depicts rollers  59 A and  59 E respectively rotating in a counterclockwise direction conducive to transporting a sheet over the top surfaces of the rollers in a right to left direction. FIG. 1 also depicts how some of the rollers (e.g., rollers  59 B and  59 D) can have smaller diameters than their neighboring rollers  59 A,  59 C and  59 E.  
         [0040]    [0040]FIG. 2( a ) shows a point in a first operating mode of the printer  10  wherein a large portion of the sheet  26  has passed through the sheet exit opening  16  and has reached a full forward position (i.e., its full rightward position-but without having completely left the printer housing). To a large extent, sheet  26  rests on top of the stack of sheets in the sheet collection tray  34 . It should be specifically noted, however, that the trailing edge  78 B of sheet  26  is still in the grip of the second sheet output roller system  67  (rollers  70  and  72 ) when the sheet achieves this full forward (rightward) position. In this full forward position, the rollers of the output roller system ( 70  and  70 A) have ceased to rotate. That is to say, roller  70  has ceased to rotate in the counterclockwise direction suggested by the arrow  70 A associated with roller  70  and roller  72  has ceased to rotate in the clockwise direction suggested by the arrow associated with it. It also should be noted that the sheet diverter  76  has not yet moved to its second operating position (i.e., it has not yet rotated counterclockwise about pivot device  76 A).  
         [0041]    [0041]FIG. 2( b ) shows the printer operating in a second mode of operation wherein the sheet  26  is traveling in a generally right to left direction depicted by arrow  79 . The diverter  76  is in its second operating position in this second mode of operation. This second operating position is brought about by rotating said diverter  76  in a counterclockwise direction about its pivot device  76 A. In this second operating position the diverter  76  presents a sheet impeding and directing surface  80  to the trailing edge  78 B of the sheet when the sheet starts to move in a backward flow direction (from right to left). Again, this backward (i.e., right to left) movement of the sheet  26  is brought about by rotating rollers  70  and  72  in their respective opposite directions from those depicted in FIG. 1( b ). In effect, most of the sheet shown in FIG. 2( b ) re-enters the printer via the same opening  16  through which most of the sheet exited the printer. Thus, the sheet exit opening  16  is capable of serving as a sheet entry opening while the printer is operating in its duplex printing mode.  
         [0042]    Those skilled in this art will appreciate that rollers  58 B and  58 C of the sheet pickup mechanism  58  must also reverse their direction of rotation in order to move the sheet in direction  79  (i.e., from right to left). That is to say that rear roller  58  rotates in the counterclockwise direction suggested by direction arrow  81 . Consequently, the direction of rollers  58 B and  58 C will be the reverse direction from the direction in which they rotate while the pick up mechanism  58  is in its first operating position wherein the axle of the roller  58 B is lowered to a level  88  such that the belt  58 A is placed in contact with a given top sheet  26  to be taken from stack  24 . In effect, theses direction changes in rollers  70  and  72  cause the trailing edge  78 B of the sheet  26  to become the sheet&#39;s “leading edge” when it moves backward (i.e., from right to left). In FIG. 2( b ) the now leading edge  78 B of the backwardly moving sheet  26  has collided with the sheet directing surface  80  of the sheet diverter  76 . In order to present the sheet directing surface  80  to the now leading edge  78 B of the sheet  26 , the diverter  76  is moved to its second operating position (i.e., it has been pivoted in a counterclockwise direction about its pivot device  76 A).  
         [0043]    Through use of sheet handling devices (such as sheet guide  82 ), the sheet  26  is then directed into contact with the sheet pickup mechanism  58 . For example, the sheet  26  is shown gripped between (1) the portion of the belt  58 A passing over the sheet pickup mechanism&#39;s rearward pickup roller  58 C and (2) a nip roller  84 . Again, the sheet pickup mechanism  58  shown in FIG. 2( b ) is comprised of a belt  58 A, a forward pickup roller  58 B and a rearward pickup roller  58 C. In effect the sheet  26  is first nipped by rollers  58 C and  84  and then carried horizontally leftward by the belt  58 A from a position defined by the nip of rear roller  58 C and roller  84  to a position defined by a nip between the portion of the belt  58 A near front roller  58 B and roller  92 . Again, the pickup mechanism  58  is depicted in FIG. 2( a ) (through use of solid lines  58 A and  58 A′ that depict a belt passing over forward pickup roller  58 B and rearward pickup roller  58 C) in its second operating position and (alternatively) in its first operating position. In this second operating position the axle of the pickup mechanism&#39;s rearward pickup roller  58 C and the axle of its forward pickup roller  58 B are shown positioned on substantially the same horizontal level  86 .  
         [0044]    In FIG. 2( b ), the pickup mechanism&#39;s first operating position is shown in dotted lines. In this first operating position, the axle of the forward pickup roller  58 B has moved to a lower horizontal level  88  so that the belt  58 A can contact a given top sheet in the stack of sheets  24  in the sheet dispensing tray  22 . When the rollers  58 B and  58 C rotate in the appropriate direction (clockwise) the top sheet is urged forward into media path  28 A. Thus, this printer may be operated in a simplex printing mode or a duplex printing mode. In any case, the first operating position of the pickup mechanism  58  is such that a given top sheet can be urged from stack  24 , delivered to the printing device  30  and then sent to collection tray  34  to a duplexing printing path. In either case, the belt/roller pickup mechanism  58  can serve a dual function. In its first operating position, it serves as a pickup device for removing a given sheet of print media from a sheet dispensing tray. In this first operating position, the drive roller (e.g., roller  58 C) rotates in a clockwise direction. In its second operating position the belt serves as a part of media path through the printer that serves to carry out a duplex printing operation. In this second operating position, the drive roller (e.g., roller  58 C) rotates in a counterclockwise direction.  
         [0045]    [0045]FIG. 2( b ), for example, shows the sheet  26  being carried by belt  58 A in a leftward direction  79 . Eventually it passes through an interface between the forward pickup roller  58 B and nip roller  92 . After passing to the left of the forward pickup roller  58 B/nip roller  92  interface, the sheet  26  is directed upward (e.g., by the guide plates  42  and  44  shown in FIG. 1( a )) into guide rollers  38  and  40  over the remainder of the first part  28 A of the overall media path. In effect, the sheet is turned over while traveling over media path  28 A. Thus, the now top side  26 B of the sheet (that was formerly the bottom side of the sheet in FIG. 2( a )) is able to receive printing from the printer device  30 . The sheet  26  then undergoes a duplex printing operation such that both sides  26 A and  26 B of the sheet receive printing.  
         [0046]    [0046]FIG. 2( c ) shows the now turned over sheet  26  being carried over the first part  28 A and second part  28 B of the overall medial path toward the exit and/or entry opening  16 . Since such a sheet will have received printing on both of its sides ( 26 A and  26 B) it will then be deposited as a finished product in the sheet collection tray  34 . In order to accommodate this, the sheet diverter  76  is shown moved back to its first operating position i.e., by rotating said diverter clockwise about its pivot device  76 A.  
         [0047]    [0047]FIG. 3( a ) depicts another sheet of print media  26 C being inserted into a second sheet entry opening  18 . Thereafter, the sheet  26 C is fed into the interface between guide rollers  38  and  40 . This sheet insertion operation can be done manually or by a sheet feeding mechanism (not shown in FIG. 3( a )). After passing the guide roller system  38 / 40 , the sheet enters the print zone between the printer device  30  and the transfer roller  56 . The sheet  26  then travels over the second part  28 B of the overall media path and into the sheet collection tray  34 . In this embodiment the second sheet entry opening  18 , the printer device  30  and the sheet exit and/or entry opening  16  are on substantially the same horizontal plane. Consequently, a sheet traveling through these three elements is not bent to any substantial degree (e.g., it is not bent more than about 300).  
         [0048]    By way of further example of this printing mode, FIG. 3( b ) shows the sheet  26 C that was depicted in FIG. 3( a ) passing through (1) the fuser  32 , (2) the roller  66 /roller  68  interface, (3) the roller  70 /roller  72  interface and (4) the exit/entry opening  16 , and on into the collection tray  34 . In traveling this path, a given sheet is not bent to any great degree (e.g., it is not bent more than about 30°). Hence, use of the printing mode depicted in FIG. 3( b ) is especially useful in those cases where the print media  26  is not a flexible sheet of paper, but rather a relatively heavy, inflexible print media material such as cardboard or a relatively stiff plastic material. A given sheet may be introduced into sheet receiving opening  18  from a sheet dispensing device (not shown), or by hand.  
         [0049]    [0049]FIG. 4( a ) depicts a sheet of print media  26 D being inserted into the printer  10  via a third sheet entry opening  20 . This sheet insertion through sheet entry opening  20  can be through use of a sheet feed tray mechanism  34 ′, or by hand. Thereafter, such a sheet  26 D is moved to the left by the sheet pickup mechanism  58  when it is in its first operating position (i.e., when the axle of its forward pickup roller  58 B is in its lower operating position  88 ). It should be noted that a sheet introduced into the printer  10  via the third opening  20  will automatically become the “top” sheet in the stack  24 —if such a stack is resting in the sheet dispenser tray  22 . Note also that such a top sheet  26 D passes under the powered belt  58 A. FIGS.  4 ( b ) and  4 ( c ) depict how such a sheet  26 D is further guided (by sheet guides  42 ,  44 , etc. and guide rollers  38  and  40 ) to the printer  30  in the same general manner as the sheet  26  depicted in FIG. 1( a ).  
         [0050]    [0050]FIG. 5( a ) depicts a cross section view of a multipath, electrophotographic printer that is provided with two sheet dispensing trays  22  and  22 A. Preferably each of the two sheet dispensing trays  22  and  22 A are serviced by separate and distinct pickup mechanisms  58  and  58 ′ as depicted in FIGS.  5 ( a ),  5 ( b ) and  5 ( c ). In another embodiment of this invention, the second sheet dispensing tray  22 A can be used to dispense a second kind of print media. In FIG. 5( a ), a given top sheet  26 E of such a second kind of print media is shown being removed from a stack  24 A of print media in the second dispensing tray  22 A. This sheet  26 E is guided toward the first part  28 A of the overall media path by a sheet guide  42 A. FIGS.  5 ( b ) and  5 ( c ) show the sheet  26  depicted in FIG. 5( a ) being further directed over the first part  28 A and second part  28 B of the overall media path and on into sheet collection tray  34 . Again, such a sheet  26 E may be the same kind, or of a different kind of print media as that dispensed from sheet dispensing tray  22 .  
         [0051]    Although specific embodiments of this invention have been disclosed herein in detail, it is to be understood that this was for purposes of illustration. Thus, this patent disclosure is not to be construed as limiting the scope of the invention since the described electrophotographic printer and printing methods may be changed in several details by those skilled in the art in order to adapt these printers to particular applications without departing from the scope of the following claims and equivalents of the claimed elements.