the invention is disclosed herein as being embodied preferably in a document scanner . because the features of a document scanner are generally known , as exemplified by the description above , the description which follows is directed in particular only to those elements forming part of or cooperating directly with a preferred embodiment of the present invention . it is to be understood , however , that various elements of the preferred embodiments described herein may take various forms known to a person of ordinary skill in the art . referring now to the drawings , fig8 shows a side view cross section through a scanner 100 of a preferred embodiment of the present invention . a back side of the scanner 121 , opposite the front side , is to the right in fig8 . the scanner is comprised of a stationary base portion 122 , a moveable pod portion 120 and a moveable output tray / flatbed cover 20 . pod portion 120 and output tray / flatbed cover 20 can both pivot or rotate relative to each other and together they can pivot / rotate relative to base portion 122 , at horizontal hinge axis 124 created by hinge mechanisms described below . the output tray 20 is at an open position when it is rotated upward ( see fig1 and 11 ) and is in a closed position when it is rotated downward and is adjacent to the flatbed scanner , as is shown in fig8 . scanner 100 provides duplex , sheet fed , c - shaped scanning and flatbed scanning functions . the sheet fed scanner input tray , output tray and the flatbed cover are all situated to face forward toward the human operator located in front of scanner 100 , which is to the left in fig8 . fig9 illustrates a perspective view of the scanner shown in fig8 with like numerals indicating like elements . referring again to fig8 , to scan a stack of documents 10 , a human operator places them , face up , on elevator input tray 11 which supports the documents and initiates a scan command through an attached computer ( not shown ) or a button or control panel ( not shown ) on the scanner . automatic operation of the scanner then proceeds as follows : drive rollers 16 begin to continuously rotate in direction 103 ; paper present sensor 17 determines that documents are in elevator input tray 11 and a motor ( not shown ) raises the tray to position the top of stack 10 against urging roller 13 ; a motor and / or clutch ( not shown ) rotate urging rollers 13 and feed rollers 15 to pull the top document from stack 10 and move it into the continuously rotating transport rollers 16 which transport or convey the document through rotary transport path ( c - shaped ) 14 in direction 110 ; the documents are imaged by cameras 18 and 19 as they are pulled through the document transport path 14 , eventually to be stacked face down in exit tray 20 . the cameras include one or more illumination sources 196 that illuminate documents to be imaged by a ccd image sensor 192 . the cameras include a lens 198 and one or more mirrors 194 to fold the light path 199 between the imager and the document and create a more compact camera . scanned documents 12 are stacked face down in exit tray 20 , in the same order as they were fed into the scanner and scanned . when paper edge sensor 101 detects the lead edge of a document , the urging rollers and feed rollers are stopped from rotating to prevent feeding of more than one document . after the trail edge of the document passes by paper edge sensor 101 via rollers 16 , the urging rollers 13 and feed rollers 15 are again rotated by motor and / or clutch ( not shown ) to start moving the next document on the top of stack 10 into transport path 14 . in this way , documents are moved one at a time past cameras 18 and 19 to be imaged . urging roller 13 is mounted to a housing 191 , that freely pivots around the axis of the upper feed roller 15 , which is attached to the pod portion 120 . therefore as documents are fed from stack 10 , urging roller 13 drops by gravity onto the next document at the top of stack 10 . stack - up sensor 102 detects when urging roller 13 ( or its surrounding parts ) drops below an optimal range for feeding documents . when this occurs , elevator 11 is raised by a motor ( not shown ) until stack - up sensor 102 detects that the stack is again in an optimal feeding position . transport path 14 is formed by surfaces 91 of base portion 122 and surfaces 93 pod portion 120 . this transport path is noted as the region between the pod portion and the base portion , with a beginning near the input tray and an exit near the output tray . after documents are scanned , they are advanced into output tray 20 where they are stacked face down , in the same order in which they were placed in input tray 11 . camera 18 resides in pod portion 120 to image the top of fed documents and camera 19 resides in base portion 122 to image the bottom of fed documents . in a preferred embodiment of the present invention , the cameras use ccd imagers . however , these cameras optionally can be either linear ccd imagers or linear contact image sensors ( cis ). located vertically above cameras 18 and 19 and disposed vertically below output tray 20 within pod portion 120 is a flatbed scanner 130 . flatbed scanner 130 includes a clear glass platen 134 , for document placement , and a camera 136 , which can be either of the linear cis or linear ccd type that images the underside of documents placed onto glass platen 134 . a preferred embodiment of the present invention uses a cis camera for the flatbed because of its small size . camera 136 is driven along a gear rack , track , or shaft 86 ( shown in fig1 ) in , or parallel to , the long direction of the flatbed scanner by a motor 132 in a manner common to flatbed scanners . fig1 illustrates a perspective view of the scanner shown in fig9 with output tray 20 in an open position exposing clear glass platen 134 . as shown in fig1 , flatbed scanner 130 is arranged so that camera 136 moves along direction 82 which is perpendicular to the direction of paper transport through the sheet fed scanner , shown as direction 110 . direction 82 is deemed the long direction of the flatbed scanner and clear glass platen . sheet fed scanner output tray 20 also serves as the cover for flatbed scanner 130 . its top surface serves as the output tray and its underside , or bottom surface , acts as a cover for the flatbed scanner . in particular , for the platen of the flatbed scanner . pad 21 is adhered to the underside of output tray 20 and it forces documents flat against flatbed glass 134 by pressing against them for scanning when closed as shown in fig9 . it is preferably formed of a flexible material in order to conform to the shape of documents or items placed on the flatbed platen . to place a document into scanner 100 for flatbed scanning , output tray 20 is lifted as shown in fig1 , pivoting about horizontal axis 124 ( fig8 ) and exposing platen glass 134 for document placement . fig1 is similar to fig8 in that it shows a side view cross section through scanner 100 but with cover 20 in an open position , also pivoted about horizontal axis 124 , while fig1 is a perspective view of a scanner 100 , similar to fig9 , but with pod 120 pivoted to an open position , and fig1 shows a side view cross section through the scanner 100 as shown in fig1 with pod 120 in an open position , with like numerals indicating like elements throughout the figures . as shown in fig1 and 13 , output / exit tray 20 pivots about the same horizontal axis 124 created by the hinge mechanisms as the pod 120 . the output tray and pod pivot or rotate independently about this axis as shown , for example , in fig1 , which also illustrates the further axial reach of the output tray 20 as compared to the pod 120 . fig1 a - c and 15 a - b show a preferred embodiment of the hinge mechanisms forming axis 124 . in fig1 a - c the output tray 20 has been removed to show the hinge mechanisms portion on one side of the pod portion 120 . pod portion 120 is pivotally attached to base portion 122 via these hinge mechanisms . bearing 150 is pressed into wall 146 of pod portion 120 . bearing 150 rotates about post 148 , which is affixed to wall 144 of base portion 122 . referring to the detail of fig1 c , which has base housing removed to expose base frame 154 , hinge post 148 is welded or riveted to metal plate 151 , which is secured to the base frame 154 with screws 153 . to assemble the scanner , the pod 120 is positioned in the base to align its bearing with the pivot axis location 124 , then the output tray ( flatbed cover ) 20 is likewise positioned at the axis . then the plate 151 with hinge post 148 is screwed onto the base frame 154 . a similar hinge / bearing arrangement at location 160 , collinear with the hinge mechanism shown , completes the pod hinge mechanisms . fig1 a - b show output tray 20 pivotally attached to base portion 122 , via the hinge mechanisms , over the same post 148 . in this case , an opening 152 in wall 150 of the output tray fits over post 148 . a similar bearing arrangement at location 161 completes the output tray hinge mechanisms . fig1 shows a preferred embodiment of opening 152 to be a slot that is oriented vertically when output tray 20 is in the closed position . this slot configuration allows output tray 20 to fully seat against thick or irregularly shaped documents that are placed on the platen for scanning . as shown in fig1 , primary user controls and / or displays 149 are positioned on surfaces that face forward toward the front of the scanner in direction 145 , which define those surfaces as the front of the machine . output tray 20 and input tray 11 extend in the same direction to provide forward facing access for the most ergonomic user interface . this configuration affords all the ergonomic benefits of the traditional rotary or c - shaped sheet fed scanner — high capacity input tray with ergonomic position close to the table surface , forward - facing trays with minimal span between them to minimize reach , forward - facing single hinge access to the rotary paper path — while also offering ergonomic flatbed scanning for exception documents even when the sheet fed input and output trays are filled with documents .