Apparatus for sorting documents

An apparatus and method for sorting documents is provided. A document transport on the apparatus conveys documents along a selected path of movement from an input bin to a series of output bins. An optical scanner, such as a video camera, is positioned along the selected path to capture images of the documents. The captured images are displayed on a display monitor to permit an operator to inspect portions of the documents for a desired characteristic. The operator activates a push button on a selector switch depending on the presence of the desired characteristic. Bins are provided for stacking and separating documents having the desired characteristic from those documents lacking the desired characteristic. Gates are provided for directing the documents to the appropriate output bin.

FIELD OF THE INVENTION 
The present invention generally relates to an apparatus and method for 
sorting documents and, more specifically, to an apparatus and method for 
acquiring images of documents and displaying those images to an operator 
to permit sorting of the documents in a selected manner in reference to 
manual input from the operator. 
BACKGROUND OF THE INVENTION 
Many companies have a need for sorting large quantities of incoming mail. 
For instance, utility companies, phone companies and credit card companies 
receive millions of envelopes from their customers on a daily basis. The 
majority of these envelopes contain an invoice stub and some type of 
customer payment, usually in the form of a bank check or money order. The 
processing of the customer payments is often dependent on information 
provided by the customer on the invoice stubs. In practice, some customers 
pay the full amount of the invoices while other customers make partial 
payments. Sorting of the customer payments is thereby necessitated to 
facilitate future billing. Additionally, many invoice stubs include some 
type of check-off box to enable the customer to provide predetermined 
information to the company. For example, a customer may mark one check-off 
box to indicate a change of address or mark another box to request 
information from the company. In certain applications, it may be desirable 
to provide further sorting of the customer mail based on the information 
provided by the check-off boxes. 
Due to the large quantity of mail received by various companies, there has 
long been a need for efficient sorting of the incoming mail into selected 
groups based on various criteria. For example, downstream processing of 
invoices and payments is more efficient when full payments are separated 
from partial payments. Sorting provides efficiencies because full payments 
can often be power-encoded, whereas partial payments generally require 
hand keying. Furthermore, a separate grouping of documents that require 
additional attention, such as the entry of a customer's new address, may 
also be preferred. 
Many companies attempt to sort documents simultaneously during the process 
in which the documents are extracted from their envelopes. Typically, an 
operator of a document extractor pulls documents out of a pre-slit 
envelope, inspects the documents, and then places the documents in desired 
groupings. Since the operator must perform multiple operations, e.g., 
document extraction, document orientation and document inspection, before 
finally making a decision about which group the documents belong, the 
operator's performance and overall throughput tend to be inefficient. 
Another approach to sorting documents entails breaking up the process into 
two separate operations. During a first operation, the documents to be 
processed are extracted from their envelopes and are then oriented in a 
selected manner. The extraction and orientation of the documents may 
either be done manually or be done automatically using a high-speed 
extractor. Either way, a second operation must then be effected to 
separate the documents into desired groupings. 
Manual separation is a laborious and time-consuming process. However, in 
many applications, manual sorting is necessary, especially when sorting 
requires human decision-making. In attempts to improve efficiency, there 
have been several automated machines developed to reduce the amount of 
manual sorting. Unfortunately, the automated approach to sorting documents 
may not be cost effective or desirable in all applications. For example, 
most checks accompanying invoice stubs are handwritten. As such, even the 
most advanced automated equipment may not be capable of reading with a 
desired degree of accuracy the handwritten dollar amounts entered by many 
customers. Additionally, many of the notes made by customers on the 
invoices require decision-making that an automated machine may not be 
capable of performing. 
In accordance with the present invention, an apparatus and method are 
provided to enable the efficient sorting of documents. The use of the 
document sorter, in accordance with the present invention, permits 
efficient operator input with automated techniques. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, an apparatus and method for 
sorting documents are provided. A document transport is provided on the 
apparatus for conveying the documents along a selected path of movement. 
Typically, the documents are conveyed along a work surface of the 
apparatus. 
A viewing area is positioned along the selected path for presenting each of 
the documents to an operator. At the viewing area, the operator may effect 
visual detection of documents having a desired characteristic. 
A selector is provided to permit activation by the operator upon visual 
detection of documents having the desired characteristic. The selector may 
be in the form of a hand-held control, may include actuator buttons on the 
work surface of the apparatus, or may be activated by the voice of the 
operator. 
A gate for directing documents is provided along the selected path of 
movement. The gate is responsive to the activation of the selector by the 
operator to direct documents having the desired characteristic to a first 
selected output area. The gate also functions to direct documents lacking 
the desired characteristic to a second select output area. 
In more specific operation, the document sorter includes a document 
transport for conveying mated pairs of documents, such as an invoice stub 
and a check, along a selected path of movement. Typically, the document 
transport conveys the documents from a document input bin to selected 
output areas, such as storage bins. The document sorter includes an 
optical scanner positioned along the selected path of movement for 
capturing an image of the mated pair of documents. The optical scanner may 
be in the form of a camera properly positionable along the path of 
movement to capture images from a selected side or sides of the mated 
pairs of documents. As an alternative, the optical scanner may include 
multiple cameras for imaging the fronts and/or backs of the documents. 
A display monitor is also provided for displaying the captured images of 
the documents to enable at least selected portions of the documents to be 
visually inspected by an operator. For example, the display monitor may 
effect the simultaneous display of the information from an amount box on 
the invoice stub and the information from the amount box on the customer 
check. In addition, a viewing area is provided along the path of movement 
for temporarily holding the sorted pair of documents while the operator is 
inspecting the images displayed on the monitor. The viewing area also 
permits the operator to inspect the actual documents, if required. 
A selector having actuator buttons is provided to enable operator input to 
the sorter. After determining into which group a pair of documents should 
be sorted, the operator designates that group by activating the 
appropriate selector button. An override button is provided to permit the 
operator to cancel or alter the original group designation for a pair of 
documents. When the override button is activated, the operator may 
designate a new group for the pair of documents by actuating the proper 
selector button. For applications involving two-group sorting, the 
documents may be automatically re-designated to a new group when the 
override button is activated. 
A stacker having a number of output bins is provided for stacking pairs of 
documents into the designated groups. Documents are directed to the 
appropriate output bin by path diverting gates positioned along the path 
of movement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As illustrated in FIGS. 1 and 2, a document sorter, generally designated 
10, is provided for sorting documents, and, particularly, mated pairs of 
documents, into predetermined groups. The document sorter 10 provides a 
work station for an operator so that manual control input may be effected 
by the operator to control operation of the sorter. The document sorter 
provides a desk-level or counter-level work surface so that the operator 
may be comfortably seated at the work station during extended operation of 
the sorter. 
As shown in FIG. 1, the sorter includes a central section 41 having a desk 
top for supporting a display monitor 38 generally at eye level of a seated 
operator and a knee hole underneath to permit the operator to draw closer 
to the monitor 38. The sorter also includes left and right return 
sections, 43 and 45 respectively, providing counter-height work surfaces 
generally within arms length of the seated operator. A document feeder 11, 
having a document input bin 12, is provided at the work surface of the 
left return 43. Documents 14 to be sorted by the document sorter 10 are 
loaded by the operator into the document input bin 12. 
A document transport, generally designated 19, conveys the documents along 
a selected path of movement generally along the work surface of the 
document sorter. More specifically, the document transport 19 functions to 
convey the documents from the input bin 12 on the left return 43 along the 
central section 41 of the sorter to an output area in the form of a 
document stacker 50 located at the work surface of the right return 45. 
Upon start-up, the documents are fed out of the input bin 12, one at a 
time, by feeder belt 20. Thereafter, several belt drives, designated as 
22, 64, 32, and 40, cooperate to transport the documents along the 
selected path of movement. 
From the document feeder 11, each document is conveyed to predetermined 
areas along the path of movement where selected images of the front and/or 
the back of each document may be captured. Images are acquired using AC 
genlocked CCTV cameras having an RS-170 interface, Exiting the feeder 11, 
each document is conveyed by belt drive 22 to front imaging area 60. If 
acquisition of the front image of that document is required, the front 
camera 66 is activated to acquire the necessary image. After the front 
camera 66 captures the image of the front of the document, the front image 
is transferred from the front camera 66 and temporarily stored in image 
memory 160. Upon completion of image acquisition by the front camera 66, 
the belt drives 22 and 64 cooperate to convey the document to a back 
imaging area 82 located on the work surface of the left return 43. If 
required, the back camera 80 takes an image of the back of the document 
and this back image is also transferred to image memory 160. 
The imaging process is repeated for each document fed into the paper path. 
As best shown in FIG. 3, the front imaging area 60 and the back imaging 
area 82 are spaced a predetermined distance along the paths of movement so 
that an image of the front of a document 24 located in front imaging area 
60 and an image of the back of a document 26 located in back imaging area 
82 can be simultaneously acquired. For mated pairs of documents, the same 
type of document from each pair is desirably oriented in the stack of 
documents to lead its corresponding document from the pair along the path 
of movement. For example, during processing of invoices and corresponding 
checks, the invoice from each pair may be selected to lead its 
corresponding check so that account information from the invoice can be 
recorded in advance of information from the corresponding check. 
Accordingly, as the front image from the invoice is captured at front 
image area 60, the corresponding check remains in a pre-feed position 17. 
After the image of the front of the invoice is recorded, the document 
transport incrementally moves the documents so that the invoice is 
positioned in the back imaging area 82 and the corresponding check is 
positioned in the front imaging area 60. The next succeeding invoice is 
also incrementally moved to the pre-feed position 17. 
The ordering of documents in the document sorter 10 and the current 
location for each document is tracked by the sorter control system. This 
is important during the imaging process because image acquisition may 
depend, in part, on the type of document being imaged. For example, it may 
be necessary to image the front and back of an invoice in certain 
applications but only necessary to image the front of a corresponding 
check. Consequently, the sorter must track the position of each type of 
document along the path of movement to ensure proper image acquisition. 
After being positioned in the back image area 82, each document is then 
transported by cooperating movement of belt drives 64 and 32 to a viewing 
area 34 located on the work surface of the central section 41 of the 
sorter. Either full images of the pair of documents or images of selected 
portions of the pair of documents are displayed on video monitor 38. 
Images of documents may be arranged on the display monitor 38 to 
facilitate fast recognition of the pertinent areas of the documents and to 
minimize eye movement which could lead to premature operator fatigue. For 
example, as illustrated in FIG. 10, enlarged images of the amount due box 
208 of an invoice 205 and the courtesy box 216 of a check 206 are closely 
spaced to enable an operator to easily and efficiently inspect the images 
of the documents, now in the viewing area 34, without having to physically 
handle individual documents. 
While inspecting the selected portions of the pair of documents on the 
video monitor 38, the operator must then decide into which group that pair 
of documents belongs, e.g. full payments, partial payments or other 
established groups. If for some reason the operator is unable to decipher 
or read the displayed images of the document pair on the monitor, the 
operator may inspect the actual documents positioned in the viewing area 
34 located generally beneath the monitor. The operator then activates one 
of the push buttons 92, 94, 96, 98, and 100 on input switch 36 to 
designate a grouping category for the pair of documents. 
Upon activation of a push button, the pair of documents is conveyed by the 
belt drives 32 and 40 from the viewing area 34 to a staging area 46 
located on the working surface of the right return 45. The staging area 46 
is spaced a predetermined distance from the viewing area 34 along the path 
of movement. Movement of the belt drives 32 and 40 is properly coordinated 
so that the pair of documents in the viewing area 34 is incrementally 
moved and then paused at the staging area 46. At the same time, the next 
pair of documents, which had been respectively positioned in the front 
imaging area 60 and the back imaging area 82, is moved into viewing area 
34 and selected images of that document pair are displayed on the video 
monitor 38. 
At this point, the operator will usually be able to decide into which group 
to place this next pair of documents currently located in the viewing area 
In some cases the operator will have inadvertently made an incorrect group 
designation for the pair of documents now located in the staging area 46. 
Usually, the operator will realize the mistake prior to making the group 
designation for the next pair of documents now located in the viewing area 
34. To correct such a mistake, the operator can activate one of the push 
buttons on the input switch 36, which functions as an override button. For 
instance, push button 100 may be designated as the override button. If the 
override button 100 is activated, the original group designation for the 
document pair now located in the staging area 46 is canceled. The sorter 
may then automatically channel the pair of documents in the staging area 
46 to a selected output area. Alternatively, the sorter may function to 
permit the entry of a new group designation on the input switch 36 for the 
documents in the staging area 46 and interpret the next succeeding entry 
as the designation for the pair of documents in the viewing area 34. 
If the override button is not activated, the pair of documents located in 
staging area 46 is then transported, upon operator activation of the input 
switch 36 for designation of the documents in the viewing area 34, to the 
stacker 50 located at the working surface of the right return 45. Upon 
entering the stacker 50, the pair of documents is directed to one of four 
output bins 51, 53, 55, and 57. One of the gates 47, 48, and 49 is fired 
to direct the pair of documents to the appropriate output bin determined 
by the designation entered at the input switch 36 for that pair of 
documents. 
Considering the operation of the sorter in greater detail, the input bin 12 
is recessed into the working surface of the left return 43. An inclined 
surface is provided at the bottom of the bin to facilitate gravity feed of 
the documents into the sorter. Two tracks 35 and 37 are provided along the 
bottom of the bin to serve as guides for a document pusher 54 to slide 
within the input bin 12. The pusher 54 includes a set of roller bearings 
that ride in each of the tracks 35 and 37 to facilitate movement of the 
pusher in a direction down the inclined surface of the bin. As the pusher 
54 slides down the inclined surface, the pusher exerts a force on the back 
of the document stack which tends to push the documents against the feed 
belt 20. 
When initially loading documents, the operator first moves the pusher 54 
away from feeder belt 20. The operator then loads the bin 12 with the 
desired batch of documents 14. After loading the documents into the bin 
12, the pusher 54 is adjusted toward feeder belt 20 to effect contact with 
the stack of documents 14. Preferably, the stack of documents 14 should be 
positioned in the bin so that the side edges of the documents are 
justified against a side wall of the input bin 12, as shown in FIG. 2. 
The bottom of input bin 12 is angled slightly downward towards the feeder 
belt 20. As a result, the documents 14 loaded in input bin 12 appear to be 
slightly shingled. Due to the downward angle of the bin 12 and the roller 
bearings of the pusher 54 riding in tracks 35 and 37, gravity causes the 
pusher 54 to exert a constant pressure on the stack of documents 14. As a 
result, documents are continually supplied from the document stack 14 into 
the sorter at feeder belt 20. 
At the appropriate time, movement of feeder belt 20 is activated and the 
next document in input bin 12 is pre-fed to a pre-feed position 17 as 
shown in FIG. 3. Actuation of a selected button on the input switch 36 
causes the first document of a document pair to be moved from the pre-feed 
position 17 to the front imaging area 60 where document movement is 
momentarily paused to enable an image to be taken of the first document in 
the front imaging area. After imaging of the first document is effected at 
the front imaging area 60, the feeder belt 60 and cooperating main 
transport belts 22 and 64 are automatically activated by the sorter to 
transport the first document to the back imaging area 82 and to transport 
the second document of the pair from the pre-feed position 17 to the front 
imaging area 60. Movement of the documents is paused until the actuation 
of a selected button of the input switch. 
A stepper motor 142, engaged with feeder belt 20, is used to accurately 
regulate the feeding of documents from the input bin 12. The actuation of 
the stepper motor 142 for a pre-determined number of steps translates into 
fixed travel distances of documents. Therefore, document positioning can 
be precisely controlled. 
Referring to FIG. 2, a sensor 58, such as an optical infrared sensor, is 
provided along the path of movement intermediate feed belt 20 and belt 
drive 22 to detect the arrival of a leading edge of the document at the 
pre-feed position 17. At the time the lead edge of a document is detected 
by sensor 58, the stepper motor 142 controlling the movement of feeder 
belt 20 is deactivated. The net effect is the precise positioning of a 
pre-fed document 17 having its leading edge located just past the sensor 
58. 
A second stepper motor 146 is engaged with belt drives 22, 64, 32, and 40 
to precisely control the movement of documents along the main transport 
path. The belt drives 22, 64, 32, and 40 of the main document transport 
are interconnected and, as such, operate in synchronism to move all 
documents positioned along the main document transport. The simultaneous 
movement of all documents in the transport permits the pitch between 
documents to remain constant. In addition, the distance between each 
document position 17, 24, 26, 28, 30, 42, and 44, as shown in FIG. 3, 
remains the same. Since the feed stepper motor 142 and main transport 
stepper motor 146 turn on at approximately the same time, the leading edge 
of each document conveyed through the document transport stops at the same 
location in each of the document positions. 
A proper handoff between the feeder 11, served by feed belt 20, and the 
main document transport, served by belt drives 22, 64, 32, and 40, is 
required to prevent tearing and crunching of documents. Coordinated 
movement is effected by simultaneously turning on the feed stepper motor 
142 controlling feeder belt 20 and the main transport stepper motor 146 
controlling the main document transport. During document handoff, both 
stepper motors are set so that the feeder belt 20 and the main document 
transport 19 are running at the same speed, resulting in a smooth transfer 
of documents from the document feeder to the main transport. 
The positions of documents are tracked during the handoff operation by 
counting the number of steps of travel by feed stepper motor 142 and 
transport stepper motor 146. After the documents travel a selected 
distance from the pre-feed location 17 and into a tight nip of main 
transport section 22, the speed of the main transport 19 may be increased 
to enhance the overall throughput of the document sorter 10. Since the 
main transport section 22 has a firm hold of the documents at the nip, the 
increased speed of main transport section 22 translates into increased 
speed of document travel. To avoid tearing of the documents, a one-way 
clutch is integrated into document feeder 11. The one-way clutch permits 
feeder belt 20 to travel at the increased speed of main transport section 
22. 
After the transfer of documents from feeder belt 20 to main transport 
section 22 is completed, the speed of feeder belt 20 automatically returns 
to the speed of feeder stepper motor 142. Additionally, the feeder stepper 
motor 142 remains activated until the next document in the input bin 12 
advances to the pre-feed location 17. 
Once a document enters the main transport section, the drive belt 22 
advances the document to position 24 at the front imaging area 60. The 
lead edge of the document at position 24 properly aligns within the right 
edge view of front camera 66, as shown in FIG. 3. 
When the document stops at position 24, the front camera 66 acquires an 
image of the document, if required. As best shown in FIG. 2, a front 
imaging plate 62, made out of glass, permits the front camera 66 to view 
the entire document without obstruction by transport belts. Foam rollers 
21, 23, and 25 are provided to press the document 24 against the front 
imaging plate 62. The foam rollers assist in positioning the entire 
document within a preselected depth of view over the entire length of the 
document, thus permitting the front camera 66 to acquire a sharp, focused 
image. 
Front camera 66 can be adjusted to provide a desired view of the document 
such as an enlarged view. For this purpose, a guide slot 68 is provided at 
the work surface of the left return 43 to permit the front camera 66 to be 
moved closer to the document to provide an enlarged view and further away 
from the document to provide a greater area of image acquisition. The slot 
68 is angled relative to the direction of movement of the document in the 
front imaging area so that the right edge view of the front camera 66 may 
be aligned with the leading edge of the document at position 24. The front 
camera 66 is mounted on a camera mounting block 72 that moves along the 
guide slot 68. The underside of the mounting block 72 includes three 
roller bearings 70, shown in phantom in FIG. 2, that ride in grooves 67 
and 69 on opposite sides of the guide slot 68, allowing the front camera 
66 to be easily positioned at a desired distance relative to document 
position 24. In addition, a locator bar 76 is provided along a side edge 
of the guide slot 68 to permit the camera 66 to be held in position at 
precise, selected locations along the guide slot 68. For this purpose, the 
locator bar 76 includes a number of anchor holes 78 located at the 
selected locations along the guide slot 68. A spring-loaded locator pin 74 
is mounted to the mounting block 72 for removable insertion into a 
selected anchor hole 78 to thereby lock the front camera 66 in a fixed 
position. The pin 74 may be removed from an anchor hole against the spring 
bias of the pin 74 to enable the camera to be moved to another selected 
location corresponding to the position of another anchor hole 78. 
After the front camera 66 acquires an image of the document 24 at the front 
imaging area 60, the next pre-fed document 17 is advanced to position 24 
and the document currently at position 24 is advanced to position 26 at 
the back imaging area 82. Document 26 is positioned within the back 
imaging area so that its lead edge is aligned within the left view of the 
back camera 80. As shown in FIG. 2, the back camera 80 may be mounted in a 
fixed position to permit imaging of the entire back surface of a document. 
Alternatively, a guide slot, similar to slot 68, may be provided to allow 
adjustment of the back camera 80 to enable the acquisition of an enlarged 
view of the back of the document at position 26. Similar to front imaging 
60, back imaging area 82 includes foam rollers 27, 29, and 31 and a back 
imaging plate 65, made out of glass, to allow acquisition of a sharp, 
focused image. 
As shown in FIG. 2, foam rollers 21, 23, and 25 engage the back of the 
document in the front imaging area 60 to transport the document through 
the front imaging area 60 while providing an unobstructed view of the 
front of the document at the front imaging area for the front camera 66. 
The foam rollers 21, 23, and 25 pinch the document against imaging plate 
62 to move the document at the front imaging area. The belt of belt drive 
22 fits into a recess in each of the foam rollers and acts to guide 
documents along the document path of the first imaging area 60. Foam 
rollers 27, 29, and 31 and belt drive 64 are positioned on the opposite 
side of the document in the back imaging area 82 so that the foam rollers 
27, 29, and 31 engage the front of the document in order to transport the 
document through the back imaging area 82 while providing an unobstructed 
view of the back surface of the document for the back camera 80 at the 
back imaging area 82. The foam rollers 27, 29, and 31 pinch the document 
against imaging plate 65 to move the document through the back imaging 
area 82. The belt of belt drive 64 is located within a recess in each of 
the foam rollers 27, 29, and 31 to guide documents along the document path 
of the back imaging area 82. 
Upon completion of image acquisition by the front camera 66 and the back 
camera 80, the main document transport 19 is again activated and all 
documents in the transport path are advanced to the next incremental 
position in the path. As best shown in FIG. 3, the document at position 26 
in the back imaging area 82 moves to position 28 in the viewing area 34, 
the document at position 24 in the front imaging area moves to position 26 
in the back imaging area 82, and the document at pre-fed position 17 moves 
to position 24. At this point, the back of the document now positioned at 
26 may be imaged by back camera 80 and the front of the document now 
positioned at location 24 may imaged by front camera 66. 
Again, upon completion of image acquisition by the front camera 66 and the 
back camera 80, all documents in the transport path are advanced to the 
next incremental position so that one pair of documents is located at 
position 28 and 30 in viewing area 34, and another pair of documents is 
located in front imaging area 60 and back imaging area 82. Selected 
portions of the documents now positioned at locations 28 and 30 in the 
viewing area 34 are displayed on the display monitor 38. The operator 
inspects the images displayed on video monitor 38 and activates one of the 
buttons on the input switch 36 to designate a selected document grouping. 
As shown in FIGS. 4 and 5, the input switch 56 includes five buttons 92, 
94, 96, 98, and 100. The operation of each button may differ, depending on 
the pre-programmed function assigned to each button. Generally, at least 
one, and as many as four, buttons are designated as selector buttons. One 
button is generally designated as an override button. In one mode of 
operation, buttons 92 and 94 function as selector buttons and button 100 
functions as an override button. In this mode, the operator's right hand 
is placed on hand rest 90, with the operator's index finger positioned 
over button 92 and the operator's middle finger positioned over button 94. 
The operator can easily activate button 92 to sort full payment documents 
and can activate button 94 to sort partial payment documents. Button 100 
serves as the override button allowing the operator to correct mistakes in 
group designations. 
The intended goal of the input switch design is to reduce operator fatigue. 
The input switch 36 includes a base having a convex outer surface of 
sufficient size allowing the operator to comfortably rest the operator's 
hand and wrist on top of the outer surface of the base. Additionally, the 
surface of the input switch 36 is contoured to comfortably fit within the 
operator's grasp. The operator can then easily actuate the push buttons 
located on the outer surface of the base of the input switch 36. Also part 
of the input switch 36 is an output port for producing an output signal to 
the control system of the document sorter 10. The output port responds to 
the actuation status of the push buttons located on the input switch. 
As an alternative to using a five button input switch, other types of 
selectors may be used for activation by an operator to designate a 
selected document grouping. For example, an input switch with a different 
number of buttons, optical reflective sensors, optical beam sensors and 
foot pedals may each be used. In addition, an operator's voice or other 
sound may be used to designate a selected document grouping. Furthermore, 
a combination of selectors may be utilized. For instance, an input switch 
having two buttons may be used to designate selected document grouping and 
voice-activation may be implemented for the override function. 
Prior to pushing a selector button and assigning a group designation to the 
pair of documents located in viewing area 34, the operator may, instead, 
push the override button 100. Activation of the override button 100 
cancels the group designation for the pair of documents at positions 42 
and 44 in the staging area 46. 
The method of assigning a new group designation to the pair of documents at 
positions 42 and 44 in the staging area depends on the override mode 
selected. In one override mode, the previous image of the documents 
positioned at locations 42 and 44 may be re-displayed on the video monitor 
38, allowing the operator to correct the group designation for that pair 
of documents by activating the appropriate selector button. In an 
alternate override mode, the activation of the override button 100 may 
automatically designate the document pair to an alternate group. The mode 
of automatically designating an alternate group is practical when 
documents are sorted into only two groups. If the operator designates an 
incorrect group, activation of the override button automatically alters 
the group designation to the other, correct group. 
If the operator does not push the override button 100 while the pair of 
documents is positioned in the staging area 46, but instead makes a group 
selection for the pair of documents in viewing area 34, the documents in 
the staging area 46 will be advanced to the stacker 50. The stacker 50 
includes a stacker transport including belt drives 86, 87, and 89 that 
conveys the documents from the main transport to the appropriate output 
bins. Unlike the feeder and main document transport, an AC motor drives 
the stacker transport. While the document sorter is in operation, the 
stacker transport runs continuously. The speed of stacker transport is 
matched to the speed of the main document transport so that a smooth 
hand-off is achieved when documents move from the main document transport 
to the stacker 50. 
The stacker 50 includes gates 47, 48 and 49 for directing documents that 
enter the stacker into one of four bins, designated as 51, 53, 55 and 57. 
A deflector 88 is included to guide documents into destination bin 57. 
Although four bins are shown, a lesser or greater number of bins may be 
provided. For example, additional bins may be used to allow water-falling 
of documents between bins. In such a configuration, a particular group 
designation may be assigned to multiple bins so that when one designated 
bin is filled, stacking of additional documents for that group will 
automatically switch to a second bin in order to permit the operator to 
continue processing documents for longer periods without having to empty 
filled output bins. 
An output bin transport 63 is provided for each output bin. The output bin 
transport 63 is in the form of a belt drive that moves documents into the 
respective output bin so that the leading edges of all the documents 
directed into such bin are justified against the back wall of the output 
bin. The output bin transport 63 cooperates with the stacker transport 
and, therefore, also runs continuously when the document sorter 10 is in 
operation. An output bin pusher 61 is also provided in each bin. The 
output bin pusher 61 is a spring-loaded arm mounted to one side of the 
output bin in position to bias against the stack of documents in the bin 
in order to maintain a neat stack of documents in the bin. 
As described, the document sorter 10 is a stand alone work station 
permitting an operator to load input bin 12 with documents 14. After 
processing, documents are sorted into output bins 51, 53, 55, and 57. 
However, the document sorter 10 can be integrated with other document 
processing equipment. For example, a document extractor may feed documents 
directly into input bin 12. Alternatively, the document extractor may 
replace the document feeder 11 entirely so that documents are transported 
from the document extractor to main transport section 22. In other 
applications, some or all of the processed documents may be directed to 
output areas other than output bins 51, 53, 55, and 57. In such a 
configuration, a smaller number of output bins or no output bins may be 
needed. For instance, pairs of full-pay documents may be directed from 
staging area 46 to a power-encoder, pairs of partial-pay documents may be 
directed to a hand-keying station, and pairs of documents having a change 
of address request may be directed to an output bin or some other output 
area. 
The processing flow of the system is illustrated in FIG. 6. At step 110, 
documents are fed into the imaging areas and at step 112 images of the 
documents are acquired. The feeding of documents to the image areas and 
the acquisition of images of the documents is a multi-step process. The 
exact imaging sequence is configurable and may vary depending on the type 
of documents being sorted. In one configuration, it may be necessary only 
to image the front side of each of a pair of documents. Accordingly, only 
front camera 66 would be activated. For customers that desire only 
front-side imaging, camera 80 can be excluded from the system. If only 
front-side imaging is required, each document of a pair will be 
successively stopped in the front imaging area 60 so that the front camera 
66 can take an image of each of the documents. 
Positioning the front camera 66 proximate document position 24 permits only 
a portion of the document to be imaged. In this configuration, the 
document at position 24 can be partially advanced within the front imaging 
area 60 by the document transport to enable the front camera 66 to take a 
second image of the same document. 
In some configurations, a back side image of only one of the documents may 
be required. For instance, where pairs of documents include an invoice and 
a check an image of only the front side of the check may be needed. The 
invoice, however, may have an invoice amount on the front side and a 
change of address request on the back side. In this case, the invoice must 
be imaged on both sides. 
After the required images of the documents are taken, portions of the 
required images are displayed on a video monitor 38 at step 114. 
Simultaneous with the image display, the pair of documents is advanced and 
stopped at the viewing area 34 at step 116. The system then continuously 
monitors input switch 36 at step 118, waiting for the operator to make a 
group designation by activating one of the push buttons 92, 94, 96, or 98. 
As soon as the system detects the activation of a push button, the 
document pair is advanced to the staging area 46 at step 120. While in the 
staging area, the operator has the opportunity to push the override button 
100 on input switch 36. The activation of the override button is checked 
at step 122. If the override button is not activated, the documents in the 
staging area 46 are advanced to the stacker 50 at step 124. 
If, however, the operator pushes the override button 100 before making the 
selection for the next pair of documents positioned in the viewing area 
34, the system alters the group destination of the pair of documents 
positioned at the staging area 46. 
In one particular mode of operation, the system may automatically re-assign 
the group designation. As an example, the system may be set up to sort 
documents into two groups. One group may be defined as a full payment 
group in which pairs of documents having equal invoice amounts and 
payments amounts are to be stacked in output bin 51. The second group may 
contain documents, having unequal invoice and payment amounts, that are to 
be stacked in output bin 53. The operator may select the first group by 
activating push button 92 and may select the second group by activating 
push button 94. As a result, activation of push button 92 directs full-pay 
pairs to output bin 51 and activation of push button 94 directs 
partial-pay pairs to output bin 53. 
During the course of sorting documents, the operator may, for example, 
inadvertently activate push button 92 when the pair of documents is, in 
reality, a partial-pay. At this point, the pair of incorrectly designated 
documents will move into the staging area 46. The operator now has the 
opportunity to push override button 100 in order to change the bin 
destination of this pair of documents. In one configuration, activation of 
the override button 100 will switch the previous decision of the operator 
and the pair of documents initially designated to go to bin 51 will 
automatically be redirected to bin 53. In an alternative configuration, 
the system may be set so that the activation of the override button 100 
will redirect the document pair to a reject bin, for example, bin 57. 
In another mode of operation, activation of the override button may cause 
the system to re-display the images of the documents in the staging area 
on the monitor to enable the operator to enter a new designation. 
Following the entry of the new designation, the images of the documents in 
the viewing area 34 will be displayed. Upon activation of the selected 
push button, the documents in the viewing area 34 will be appropriately 
designated and moved to the staging area 46 while the documents in the 
staging area 46 will be directed to the bin corresponding to the new 
designation. 
An electrical block diagram of the control system is shown in FIG. 7. A 
system control board 130 controls basic operations of the document sorter 
10. A user interface is provided through an LCD display 132 and keypad 
134. An operator may input commands, change machine and job parameters, 
and retrieve statistical information through keypad 134. Status of the 
system and input prompts may be displayed on LCD display 132. 
Various output devices may be controlled by the system control board 130 
through signal processor board 136, which isolates the system control 
board 130 from the rest of the system. Stepper motor control 140 controls 
the feeder stepper motor 142. Stepper motor control 144 is provided for 
controlling the main document transport stepper motor 146. 
A relay control board 148, controlled by the system control board 130 
through signal processor board 136 is used to activate the AC motor 150 
which is used to drive the stacker transport. The relay control board 148 
also controls gate operation 152 by controlling outputs to gates 47, 48, 
and 49. 
The system control board 130 also monitors the status of the selector 
switch 36 and sensor operation 138 through signal processor board 136. A 
cable 102 between the input switch 36 and the signal processor board 136 
includes five sensor lines for detecting whether one of the push buttons 
92, 94, 96 and 98 or override button 100 has been activated by the 
operator. 
The control system of the document sorter 10 includes a number of sensor 
inputs 138. Feeder sensor 58 is used to locate pre-fed documents and to 
control the transfer of documents between the feeder 11 and the main 
document transport 19. In addition, several other path sensors are located 
along the main transport path to detect the arrival and departure of 
documents. If a document does not arrive at a particular sensor at the 
appropriate time, a jam condition is declared and the operator is notified 
about the jam through LCD display 132. Bin full sensors are provided in 
each of the output bins 51, 53, 55 and 57 to alert the operator of a full 
bin condition. If multiple bins have been designated for a group, a bin 
full condition will cause the system to divert documents to an 
appropriately designated non-full bin. However, if all bins allocated to a 
particular group are filled, the control system halts processing of 
documents and prompts the operator to empty the full bins through the LCD 
display 132. 
The video control board 154 controls acquisition of the images by cameras 
66 and 80. The video control board 154 also controls the display of images 
on the video monitor 38. 
The video controller board 154 communicates to the system controller board 
130 via a serial communication channel at a rate of 9600 baud. The 
communication line between the video controller board 154 and system 
controller board 130 runs through signal processor 136. The video control 
board 154 receives commands from the system control board 130. For 
example, the video control board 154 may be directed to display a 
particular image or to have one of the cameras acquire an image of a 
document. The video control board 154 reports successful completion of a 
command to the system control board 130. 
Referring to FIG. 8, the video control system includes four image buffers, 
generally designated 160, and a display buffer 170. The video control 
board 154 directs images acquired by the front camera 66 and the back 
camera 80 to one of four image buffers 162, 164, 166 or 168. For example, 
the front side of the first document acquired by the front camera 66 may 
be loaded into image buffer 162, the front side of the second document may 
be loaded into image buffer 164, and the back side of the first document 
may be loaded into image buffer 166, and image buffer 168 may be left 
unused. When commanded by the system control board 130, the video control 
board 154 loads portions of one or more image buffers 160 into one of 
eight display sections 172, 174, 176, 178, 180, 182, 184 and 186 of 
display buffer 170. By way of example, two portions of image buffer 1 
(162) may be loaded into display section 1 (172) and display section 2 
(174), respectively. In addition, a section of image buffer 2 (164) may be 
loaded into display section 3 (176) and a portion of image buffer 3 (166) 
may be loaded into display section 4 (178). Image buffers 160 are of a 
fixed length. Each image buffer 162, 164, 166, and 168 holds a full image 
acquired by front camera 66 and back camera 80 so that four full images 
may be stored simultaneously. 
Display buffer 170 is a FIFO memory having a sufficient size to support a 
640.times.480 monochrome VGA monitor. The eight display sections are 
logical divisions of the display buffer 170. Not all sections of display 
buffer 170 are required to be used and the physical size of each section 
is not fixed. 
The configuration and use of the display buffer 170, as well as the 
operation of the document sorter, may be better understood by reference to 
FIGS. 9-12. In forming the display of FIG. 9, a full-size camera view 200 
of the first side of the first document 205, such as an invoice, is 
displayed on the video monitor. The full-size view 200 matches the size of 
the image of the first document 205. Also shown on the video monitor is a 
second full-size camera view 202 in which only a portion of the full-size 
view 202 incorporates a full image of the front side of the second 
document 206, such as a check. The remaining portion of second image 202 
is background 204, which in essence is the background area of the front 
imaging area 60. 
To display the image shown in FIG. 9, the video control board 154 transfers 
an acquired front image of an invoice from front camera 66 to image buffer 
1 (162). In addition, the video control board 154 transfers an acquired 
front image of a check from front camera 166 to image buffer 2 (164). 
Furthermore, after receiving a command from the system control board 130, 
the video control board 154 loads the entire contents of image buffer 1 
(162) into display section 1 (172) at a location in display buffer 170 so 
that the full image of the first document appears on video monitor 38 as 
shown in FIG. 9. Likewise, the video control board 154 transfers the 
entire image buffer 2 (164) to display section 2 (174) resulting in a full 
display of image 202. 
As shown in FIG. 9, the selection of display sections in the display buffer 
170 are in a horizontal relationship to one another. Such a display 
configuration is the result of transferring images from image buffers 160 
to the FIFO of display buffer 170. In addition, during this transfer, a 
grey level, specified by the system control board 130, is loaded in the 
FIFO to serve as a grey background 222 around the displayed images 200 and 
202. 
Alternative configurations of images may be displayed on the video monitor 
38 as shown in FIGS. 10-12. Referring to FIG. 10, an enlarged image of an 
amount due box 208 appearing on document 205 and an enlarged image of a 
courtesy amount box 216 appearing on document 206 are displayed on the 
monitor. The display shown in FIG. 10 results from moving the front camera 
66 along slot 68 into closer proximity to the document position 24. The 
video control board 154 transfers a portion of image buffer 1 (162) 
containing a partial image of document 205 into display section 1 (172) 
and transfers a portion of image buffer 2 (164) containing a selected area 
of check 206 into display section 2 (174). 
The display on the monitor depicted in FIG. 11 results from the acquisition 
of two separate front images of invoice 205 and one front image of check 
206 by front camera 66. Image buffers 1 and 2 (162 and 164) contain 
separate portions of document 205 and image buffer 3 (166) contains a 
portion of check 206. The video control board 154 transfers the image 
buffers 1, 2, and 3 (162, 164, and 166) to display section 1, 2, and 3 
(172, 174, and 176) resulting in the display shown in FIG. 11. 
Referring to FIG. 12, the display of eight separate sections of display 
buffer 170 are shown. In achieving this display, a full image of the front 
of invoice 205 and the front of check 206 is acquired. In addition, an 
image of the back of invoice 205 is acquired. The amount due box 208 of 
invoice 205 and the courtesy amount box 216 of check 206 are loaded into 
display sections 1 and 2 (172 and 174), respectively. The OCR line 214 of 
the invoice 205 is loaded into display section 3 (176). The payee section 
220 of check 206 is loaded into display section 4 (178). The signature 
area 218 of check 206 is loaded into display section 5 (180). In addition, 
three portions of the back of invoice 205 are displayed, designated as 
226, 228, and 230, each such portion having been loaded into display 
sections 6, 7, and 8 (182, 184, and 186). 
The operation of the document sorter 10, and, in particular, the 
configuration of the displays is a representative sample of the system 
flexibility. For example, the document sorter 10 may be used in various 
other configurations. For instance, the sorting of single documents, 
rather than document pairs, may be effected. In this configuration, an 
operator may designate the existence or absence of a particular 
characteristic on single documents. In an alternate configuration, a 
keyboard may be added to the system to allow the operator to add 
additional information, for example, a customer's new address. 
In addition, the decision-making of an operator may be combined with a 
decision produced by the control system of the document sorter 10. For 
instance, the operator may be assigned the task of determining whether to 
designate a pair of documents as a full-pay or partial-pay using a 
manually actuatable selector. In such an instance, a display such as the 
one shown in FIG. 10 may be used. While the operator is making the 
full-pay/partial-pay determination, an address change detect module on 
video control board 154 may be utilized to automatically determine whether 
the customer has checked off an address change box on an invoice. The 
operator's decision and the decision of the video control board 154 can 
then be combined resulting in a designation of four groupings. For 
example, full-pays without address change may be directed to output bin 
51, full-pays with address change may be directed to output bin 53, 
partial-pays without address change may be directed to output bin 55, and 
partial-pays with address change may be direct to output bin 57. 
Furthermore, the document sorter 10 may be used in a continuous mode of 
operation. In such a mode, images of single documents or document pairs 
may be acquired and displayed on video monitor 38. The operator is 
required to actuate a selector button only when a pair of documents having 
a desired characteristic is displayed on the monitor 38. No selection 
needs to be made for documents lacking the desired characteristic. By way 
of example, it may be determined that the typical mix of documents in 
input bin 12 contains ninety percent full payments and ten percent partial 
payments. As such, the desired characteristic may be documents having a 
partial-payment. In the continuous mode of operation, documents are 
continuously conveyed through the document sorter 10. When the operator 
determines that a partial-pay is displayed on the video monitor 38, the 
operator actuates the selector and, in response, the documents are 
directed to the appropriate output area for partial-pay documents. The 
selector is not actuated, however, when a full-pay appears on the video 
monitor 38 and, in response, the full-pay documents are automatically 
directed to the appropriate output area for full-pay documents. 
In yet another mode of operation of the document sorter 10, the optical 
scanner and display monitor may be excluded from the system. In such a 
configuration, documents 14 are conveyed from the input bin 12 directly to 
the viewing area 34. The operator may then inspect the documents by 
viewing them directly or viewing them through a magnifying lens. The 
operation of the push buttons and override button may function as 
previously described. 
It will be recognized by those skilled in the art that changes or 
modifications may be made without departing from the broad inventive 
concepts of the invention. It should therefore be understood that this 
invention is not limited to the particular embodiments described herein, 
but is intended to include all changes and modifications that are within 
the scope and spirit of the invention as set forth in the Claims.