Method and apparatus for feeding and stacking articles

An envelope processing system (20) includes an input transport section (22); a processing/transport section (24); and a discharge transport section (28). Envelopes are fed on-edge from the input transport section to the processing/transport section (24) by a feeder section (40) comprising a feeder (72) and a feed assist device (80). When a signal controller (190) monitoring the feeder (72) detects a significant delay between the feeding of envelopes, the feeder (72) is enabled to acquire greater contact with the next envelope by displacing the feed assist device (80) out of its normally biased co-planar position with a feed belt (130) of the feeder (72), resulting in a greater force vector on the next envelope in the direction toward a singulation region (73). A stacker section (38) comprising the discharge conveyance section (28) includes introductory conveying means (302), stacker conveying means (304), and a discharge magazine (300). An introductory path (360) is oriented at an acute angle ( 362) with respect to a processing path (26) of the processing/transport section (24). In the stacker conveying means (304), belts (370) follow a triangular course of travel, through which a trailing edge of an envelope "fishtails" (i.e., is deflected) about a bend point (391) with the assistance of a rotatable positioning element (394). An abutment wall (322) has an interior cavity (336) filled with acoustic insulating material (338). Vertically-oriented ridges (340) on the abutment wall (322) serve as bearing points to reduce frictional drag between the wall (322) and the envelopes. Envelopes are registered against the abutment wall (322) by the positioning element (394).

BACKGROUND 
1. Field of the Invention 
This invention pertains to the feeding and stacking of items such as 
stuffed envelopes, and particularly to methods and apparatus for feeding 
and stacking such items on-edge. 
2. Prior Art and Other Considerations 
The prior art includes teachings of envelope processing systems wherein 
envelopes in a stack are conveyed on-edge in a feed direction toward a 
feeder for redirecting the envelope toward a singulation gap. The feeder, 
such as an revolving endless belt, for example, contacts a sidewall of a 
lead envelope for directing the lead envelope, in a direction orthogonal 
to the feed direction, toward the singulation gap. 
Prior art envelope processing systems of the type just described have 
considerable difficulty in handling envelopes of varying thicknesses. 
Accordingly, significant problems are encountered when the same envelope 
processing system is expected to run a batch of envelopes which includes 
both thick and thin stuffed envelopes. If the singulation gap is sized for 
large envelopes, then a plurality of envelopes ("doubles") might be fed 
essentially simultaneously through the singulation gap. On the other hand, 
if the singulation gap is sized for small envelopes, the envelope 
processing system may fail to direct a thicker envelope toward and through 
the singulation gap. 
Envelope processing systems which handle onedge envelopes also are very 
awkward in stacking envelopes after the envelopes have undergone a 
processing (such as character reading or label printing). The potential 
interference with envelopes already-stored in a discharge stack poses 
problems for the introduction of an another on-edge envelope into the 
stack. Such unwelcomed interference is typically occasioned by a 
potentially obstructive path of envelope travel; by a high degree of 
friction between envelopes and the stack-defining structure wherein they 
travel; and, by difficulty in obtaining and maintaining proper 
registration of the envelopes introduced into the discharge stack. 
In view of the foregoing, an object of the present invention is the 
provision of method and apparatus for facilitating the handling of 
envelopes of varying thicknesses by an on-edge envelope processing system. 
An advantage of the present invention is the provision of method and 
apparatus for facilitating the feeding of envelopes of varying thicknesses 
in an on-edge envelope processing system. 
Another advantage of the present invention is the provision of method and 
apparatus for facilitating the introduction of processed envelopes into a 
discharge stack wherein the envelopes are oriented on-edge. 
A further advantage of the present invention is the provision of method and 
apparatus for facilitating the smooth and silent stacking of on-edge 
envelopes in a discharge stack wherein envelopes are oriented on-edge 
SUMMARY 
An envelope processing system includes an input transport section; a 
processing/transport section; and a discharge transport section. Envelopes 
are fed on-edge from the input transport section to the 
processing/transport section by a feeder section. The envelopes travel 
on-edge and one-at-a-time through the processing/transport section which 
includes an optical character reader and a bar code printer. From the 
processing/transport section the envelopes are loaded onedge onto the 
discharge transport section by a stacker section. 
In the feeder section, a foremost envelope in an input magazine contacts a 
feeder and a feed assist device (also known as a "helping hand"). The 
feeder directs the foremost on-edge envelope toward a singulation region 
(defined by a first pair of rollers, including a driven "pull-out" 
roller). The singulation region includes a first stage singulation gap 
(defined between a feed belt and an adjustably-biased singulation member) 
and a second stage-singulation gap. 
A signal controller monitors when the feeder is having difficulty in 
feeding an envelope by timing the delay elapsed since the feeding of a 
previous envelope In this respect, if a predetermined number of envelopes 
are not detected as having passed through the singulation region in a 
given unit of time, the signal controller presumes that the feeder is 
experiencing difficulty in feeding the next article, likely because of a 
greater thickness of the next article. In such a case, the signal 
controller enables the feeder to acquire greater contact with the next 
envelope by displacing the feed assist device out of its normally biased 
co-planar position with the feed belt of the feeder. This is done by 
sending a signal to an assist displacement control means, which signal 
causes the displacement of a feeler-switch-borne translatable block. 
Movement of the feeler switch away from the feed assist means, and 
particularly out of contact with a cam surface of a feed assist carriage, 
results in the activation of an input transport motor. Activation of the 
input transport motor resumes incremental advancement of on-edge stacked 
envelopes toward the feeder and the feed assist means, with a resulting 
greater pressure bearing against the displaceable feed assist means. When 
the bias of the feed assist means is overcome by such pressure, the feed 
assist means is displaced further away from a plane of tangency T with the 
feeder belt, so that the feeder belt has greater contact with the thick 
envelope. The greater contact of the feeder assist means with the thick 
envelope and the greater pressure urging the contact of the two results in 
the application of a greater force vector on the thick envelope in the 
direction of the compliant roller pair forming the singulation gap. 
The feeder section comprises a selectively revolvable feeder belt entrained 
about two pulleys, one of the pulleys being a driven/braked pulley and the 
other pulley being an idler pulley. A portion of the course of travel of 
the belt lies in a tangent plane T which is essentially parallel to the 
sidewalls of on-coming envelopes and which contacts the sidewall of the 
foremost envelope in the input magazine. Revolution of the driven pulley 
causes revolution of the feeder belt, with the frictional contact of the 
belt with the foremost envelope serving to direct the foremost envelope 
toward the singulation gap. In one embodiment of the invention, the axes 
of the two rollers comprising the feeder are fixed vertical axes. In a 
second embodiment, the axis of the driven roller is a fixed vertical axis, 
while the vertical axis of the idle roller is pivotal about the fixed 
vertical axis of the driven roller. In the second embodiment, revolution 
of the feeder belt causes the idle roller to pivot, which in turn causes 
the feeder belt to pivot or kick in towards the foremost envelope, and 
thereby apply a greater vector force to direct the foremost envelope 
toward the singulation gap. 
The stacker section is downstream from the processing/transport section to 
receive envelopes tranported on-edge thereto. The stacker section includes 
introductory conveying means, stacker conveying means, and a discharge 
magazine. The introductory conveying means comprises O-ring pairs which 
direct an on-edge envelope along an introductory path. This introductory 
path is oriented at an acute angle with respect to a processing path of 
the processing/transport section. The introductory conveying means directs 
an article toward the stacker conveying means, so that a leading edge of 
the envelope strikes a pair of vertically-spaced belts forming the stacker 
conveying means. The stacker belts follow a triangular course of travel, 
and define a first linear path segment and a second linear path segment. 
In directing an envelope along the first linear path segment, the stacker 
conveying means causes the envelope to be deflected through an obtuse 
angle with respect to the introductory path. 
In the following the first linear path segment defined by the stacker 
conveying means, the leading edge of an envelope is directed to a vertex 
of the stacker belt triangular path for interposition between a previously 
stacked envelope and the stacker belts. That is, as the leading edge of 
the envelope reaches a pulley forming a vertex of the triangular path, the 
leading edge is interposed between the midsection of the previously 
stacked envelope and the stacker belts at a bend point whereat the stacker 
belts turn at an obtuse angle to define a second linear path segment. This 
second linear path segment is thus the second leg of the triangular path. 
As a leading envelope edge rounds the bend point and travels up the second 
linear path segment between the stacker belts and the previously stacked 
envelope, the trailing edge of the envelope "fishtails" (i.e., is 
deflected) through an angle which is acute with respect to the first 
linear path segment. The fishtailing is prompted by the geometrical 
configuration of the path traveled by the envelope at the bend point, and 
is further facilitated by the operation of a rotatable positioning 
element. 
In the above regard, an elongated rotatable positioning element is provided 
in the plane of the discharge magazine. The positioning element is 
basically threaded along a first portion thereof with the helical threads 
extending just slightly above the plane of the discharge magazine. The 
rotating threads of the positioning element catch the bottom of trailing 
edges of envelopes and displace the trailing edges at least partially 
through the fishtail angle. 
As envelopes travel along the second linear path segment the leading edges 
thereof strike an abutment wall forming the discharge magazine. The 
abutment wall has an interior cavity which is filled with acoustic 
insulating material, so that contact of the leading edge does not result 
in an audibly loud pop. 
As the number of envelopes increases in the discharge magazine, the stack 
of envelopes in the discharge magazine exerts pressure, through the most 
recently stacked envelope, against a pressure sensor. The pressure sensor 
has a pivotal sensor arm which extends through a gap in the two vertically 
spaced belts forming the stacker conveying means. When the envelope 
pressure in the stack overcomes a biasing force on the sensor arm, the 
sensor contacts a microswitch, which in turn activates a discharge 
transport motor to carry onedge envelopes away from the stacker section. 
As the envelopes travel away from the stacker section, vertically-oriented 
ridges on the abutment wall serve as bearing points to reduce frictional 
drag between the abutment wall and leading edges of the envelopes. 
Moreover, envelopes are registered against the abutment wall by the 
operation of a second portion of the rotatable positioning element. In 
this regard, the second portion of the rotatable positioning element has 
arcuate surfaces thereon which periodically extend above the plane of the 
magazine floor, and thereby slightly elevate the trailing edge of the 
envelope, so that the envelopes experience a force vector toward the 
abutment wall.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 shows a system 20 for processing flat articles, such as envelopes. 
System 20 comprises an input transport section 22; a processing/transport 
section 24 wherein flat articles, such as envelopes, are transported along 
a processing path 26; and, a discharge transport section 28. The 
processing system 20, hereinafter also referred to as an envelope 
processing system 20, also includes a keyboard 32; a monitor 34; and, a 
printer 36. 
Envelopes are fed on-edge from the input transport section 22 to the 
processing/transport section 24 by feeder section 40. The envelopes travel 
on-edge and one-at-a-time through the processing/transport section 24. 
From the processing/transport section 24 the envelopes are loaded onto the 
discharge transport section 28 by stacker section 38. 
The direction of envelope travel on the input transport section 22 is shown 
by arrow 42; the direction of envelope travel from section 22 onto the 
processing/transport section 24 as propelled by the feeder section 40 is 
shown by arrow 44; and, the direction of envelope travel on the discharge 
transport section 28 is shown by arrow 45. The direction of envelope 
travel on the processing/transport section 24 is perpendicular to the 
direction of envelope travel on the input transport section 22 and the 
discharge transport section 28. 
In the particular embodiment under discussion, the processing/transport 
section 24 directs envelopes along the processing path 26 which has reader 
means 50; a detector photocell 52; and bar code printer means 54 
positioned therealong. It should be understood that in other embodiments 
of the invention, other and/or additional functions can be performed along 
the processing path 26. 
In the embodiment illustrated in FIG. 1, the reader means 50 includes an 
optical character recognition (OCR) read head 56 and associated 
electronics for reading alphanumeric information on the sidewall of an 
on-edge envelope and for generating signals indicative thereof. The bar 
code printer means 54 includes an ink jet (IJ) printer nozzle 60 and 
associated ink jet electronics for applying a bar code to the sidewall of 
an on-edge envelope transported by the nozzle 60. In the illustrated 
embodiment, the bar code printer means 54 is a Videojet III Bar Code 
Printer provided by Videojet Systems International. 
Envelopes are transported on-edge through the processing/transport section 
24 in the direction of arrow 44 by a transport system 62 which includes a 
series of revolving horizontal belts 64 and a series of revolving vertical 
belts, including front vertical belts 66 and back vertical belts 68. The 
bottom edges of envelopes ride on the horizontal belts 64, while the front 
sidewalls and back sidewalls of the envelopes are contacted by the belts 
66 and 68, respectively. 
STRUCTURE: FEEDER SECTION 
As shown in FIG. 2, the feeder section 22 of the envelope processing system 
comprises an input magazine 70; feeding means, such as feeder 72; means 
for defining a singulation region 73, including first stage singulation 
means 74 and second stage singulation means (including rollers 75 and 76); 
feed assist means 80 (also known as a "helping hand"); feed interval 
detection means 82; and, assist displacement control means 84. As will 
hereinafter be described, envelopes in the input magazine 70 (shown as 
envelopes 86A through 86N in FIG. 2) are sequentially advanced on-edge to 
feeder 72. The feeder 72 directs a leading flat envelope in the input 
magazine 70 (envelope 86A) in a feed direction (indicated by arrow 88) 
toward the singulation region 73 from whence the envelope 86A is further 
conveyed along the processing path 26. 
The input magazine 70 comprises a magazine frame 100 having a horizontal 
top surface 102. Standing vertically on the magazine surface 102 is an 
envelope guide wall 103 which extends along the input transport direction 
(shown by arrow 42) near the left edge of frame 100. A similar wall 104 is 
provided near the right edge of frame 100. Two posts 106A and 106B also 
stand errect on the magazine surface 102 near the envelope guide wall 104. 
Although equipment housing 107 hides post 106B in FIG. 1, FIG. 2 shows 
housing 107 removed and post 106B exposed. A guide rod 108 has a first end 
thereof connected to the post 106A and a second end thereof connected to 
the post 106B, so that guide rod 108 is held aloft and extends parallel to 
the input transport direction 42. 
The input magazine 70 also includes input transport means 110 for 
transporting envelopes on-edge to the feeder 72. The input transport means 
110 comprises three endless transport belts 112A, 112B, and 112C having 
upper courses of travel which extend over the magazine top surface 102. 
Each of the transport belts, 112A, 112B, 112C is entrained about a 
corresponding driven pulley 114A, 114B, 114C (situated under magazine top 
surface 102 near an entrance end of the input magazine 70) and a 
corresponding (unillustrated) idler pulley, so that the transport belts 
112A, 112B, 112C travel in the input transport direction 42. The driven 
pulleys 114A, 114B, and 114C are commonly mounted on rotatable shaft 116. 
Rotatable shaft 116 is driven by input transport motor 118, which provides 
power to rotate the pulleys 114A, 114B, 114C for propelling the transport 
belts 112A, 112B, 112C, the envelopes carried thereon, toward the feeder 
72. 
In the illustrated embodiment, each of the transport belts 112A, 112B, 
112C, is an elastomeric timing belt having teeth 120 provided thereon at 
regularly spaced intervals. Between adjacent ones of the teeth 120 is a 
trough 122. So configured, the belts 112A, 112B, 112C with teeth 120 and 
troughs 122 are well suited to engage bottom edges of the envelopes 
carried on-edge thereon. 
The input magazine 70 also includes a compression plate 124. Compression 
plate 124 has a hollow sleeve member 126 which fits over the guide rod 
108, so that compression plate 124 is rotatable about guide rod 108 (away 
from the magazine top surface 102) and is translatable along guide rod 108 
(along the input transport direction 42). Compression plate 124 is 
essentially a rectangular flat plate which, when left in its ordinary 
orientation, extends across the top surface 102 of the input magazine 70 
in a direction perpendicular to the direction 42 of transport, resting on 
the tops of the transport belts 112A, 112B, 112C. As will be seen 
hereinafter, when the transport belts 112A, 112B, 112C are incrementally 
driven in the input transport direction 42, the compression plate 124, 
resting on transport belts 112A, 112B, 112C is also advanced toward the 
feeder 72, with the result that envelopes between the plate 124 and the 
feeder 72 are compressed further toward the feeder 72. 
The feeder 72 of the embodiment of FIG. 2 comprises an endless belt 
entrained about feeder rollers 132 and 134. Both feeder rollers 132 and 
134 are mounted to rotate about respective stationary vertical axes. 
Feeder roller 132 is connected (below the plane of surface 102) by drive 
belt 136 to a clutch/brake mechanism 138. Clutch/brake mechanism 138 is in 
turn connected by belt 139 to feeder motor 140. When the feeder motor 140 
is activated and the clutch brake is energized, the first feeder roller 
132 rotates about its vertical axis in the direction shown by arrow 141, 
thereby imparting clockwise momentum to the endless belt 130 entrained 
about rollers 132 and 134. Roller 134 is an idle roller, which rotates 
about its vertical axis as endless belt 130 moves in its clockwise 
direction. As described hereinafter, as the endless belt 130 moves in the 
clockwise direction, the endless belt 130 contacts a first surface (i.e., 
a first sidewall) of the leading envelope 86A in the input magazine and 
exerts a force vector on the envelope 86A in the feed direction (shown by 
arrow 88), with the result that belt 130 imparts momentum to envelope 86A 
toward the singulation region 73. 
As indicated above, the singulation region 73 comprises a first-stage and a 
second stage. A first stage singulation gap 142, seen in FIG. 16, is 
defined between the first stage singulation means 74 and the belt 130 of 
feeder 72. A second stage singulation gap 143 is defined between the 
rollers 75 and 76. 
The first stage singulation means 74 includes disc-shaped singulation 
stones 144A and 144B. The singulation stones 144A and 144B are secured to 
opposite ends of a vertical shaft 145 which extends through the centers of 
the stones 144A and 144B. Shaft 145 is, in turn, carried by a lever arm 
146. The lever arm 146 pivots about studs 147A and 147B. Studs 147A and 
147B are mounted to the horizontal magazine surface 102. The lever arm 146 
pivots about studs 147A and 147B through link members 148A and 148B and 
associated link pins 149A and 149B. 
The lever arm 146 carries a rotatable nylon roller 150. The nylon roller 
150 is rotatably mounted on a second vertical shaft 151. The shaft 151 is 
carried on lever arm 146 so that the axis of shaft 151 and roller 150 are 
closer to the feeder 72 (in the sense of the direction of arrow 42) than 
are shaft 145 and the axis of stones 144A and 144B; and so that the axis 
of shaft 151 and roller 150 is more upstream (in the sense of the 
direction of arrow 88) than are shaft 145 and the axes of stones 144A and 
144B. With the shafts 145 and 151 so positioned, the periphery of roller 
150 is further upstream (in the sense of the direction of arrow 88) than 
are the peripheries of stones 144A and 144B. 
The first stage singulation means 74 is biased in the direction of the 
feeder 72 (i.e., in the direction of arrow 42) by biasing means 152. 
Biasing means 152 comprises biasing spring 153, a first end of which is 
secured to the link member 148A and a second end of which is secured to 
anchor block 154. Anchor block 154 is in turn secured to the horizontal 
magazine surface 102. Anchor block 154 carries a threaded adjustment screw 
155. The adjustment screw 155 has a head which bears against an extended 
portion of link member 148A. The relative position of the head of 
adjustment screw serves as a limit for the biasing means 152, and thus 
controls the width of the first singulation gap 142. 
In the vicinity of the stones 144A, 144B the lever arm 146 carries two-wing 
members 156A, 156B. Wing members 156A, 156B straddle the roller 76 and 
thus prevent thin envelopes from wrapping around the roller 76 in the 
reverse direction. 
Turning now to the second stage singulation gap 143, the roller 76 is a 
compliant roller having a circumferential surface that touches roller 75. 
Both rollers 75 and 76 are rotatable about corresponding fixed vertical 
axes. As shown in FIG. 2, roller 75, also known as the "pull-out" roller, 
is oriented so that its circumferential surface contacts the first flat 
side of an envelope 86 as the envelope 86 goes through the second stage 
singulation gap 143. Roller 76, positioned just across gap 143 from roller 
75, is oriented so that its circumferential surface contacts the second, 
or opposite, side of the envelope 86. 
Downstream from the rollers 75 and 76 along the feed direction (indicated 
by arrow 88) is a second pair of rollers, particularly third roller 157 
and fourth roller 158. Like rollers 75 and 76, rollers 157 and 158 are 
oriented for rotation about fixed vertical axes. Roller 157 is situated to 
contact the first side of envelope 86; roller 158 is situated to contact 
the second side of envelope 86. 
Roller 157 is continuously rotationally driven in the clockwise direction 
by virtue of its connection (via belt 159) to motor 160. The rotational 
motion of roller 157 is transmitted to pull-out roller 75 by belt 161 so 
that roller 75 rotates in the clockwise direction. 
In the embodiment of FIG. 2, the roller 76 is connected via belt 162 and 
slip clutch 164 (positioned beneath roller 76) to the power drive for 
roller 157. As described hereinafter, in the event a tendency for a 
multiple feed is detected, the roller 76 can be rotated in the clockwise 
direction to repel any second envelope (such as envelope 86B in FIG. 1) 
that might attempt to simultaneously enter the second stage singulator gap 
143, along with the leading envelope (i.e., envelope 86A). In another 
unillustrated embodiment, the roller 76 is merely an idler roller which is 
not connected to roller 157. 
Two detectors are positioned downstream from the singulation gap 78, 
particularly singulator blockage detector 170 and singulator clearance 
detector 172. The singulator blockage detector 170 comprises photocell 
transmitter 174 and photocell receiver 176 oriented to direct a beam 178 
transverse to the direction of feed transport 88. The beam 178 crosses the 
direction of feed transport 88 at a point downstream from rollers 75 and 
76 whereby, when a leading edge of an envelope trips the beam 178, an 
envelope is travelling through the second stage singulator gap 143. 
The singulation clearance detector 172 comprises photocell transmitter 180 
and photocell receiver 182 oriented to direct a beam 184 transverse to the 
direction of feed transport 88. The beam 178 crosses the direction of feed 
transport 88 at a point downstream from rollers 157 and 158. 
The photocell receivers 176 and 182 are connected by lines 186 and 188, 
respectively, to input ports of a signal controller 190. The signal 
controller 190 has output ports connected by lines to various devices 
controlled thereby, including line 192 connected to the clutch/brake 
mechanism 138 associated with feeder 72. As indicated by its description 
hereinafter, to the extent utilized by the present invention, the signal 
controller 190 basically serves to time the application of signals to the 
mechanisms controlled thereby, and thus comprises conventional circuitry 
well understood by the man skilled in the art. 
In one embodiment, the signal control receives signals from the reader 
means 50 as an indication of the frequency of envelopes clearing the 
singulator region 73, rather than receiving signals from the singulator 
clearance detector 172. 
The transport system 62 of the processing/transport section begins in the 
neighborhood of the singulator clearance detector 172. That is, the 
rotatable horizontal belt 64 and the vertical belts 66 and 68 are 
positioned to catch articles fed from between roller pair 150, 152 and to 
direct the articles along the processing/transport section 24 in the 
direction of arrow 44. 
The feed assist means 80, also known as the "helping hand", includes a feed 
assist carriage 200 that comprises an essentially cylindrical member 202. 
The major cylindrical axis of cylindrical member 202 is parallel with the 
input transport direction 42. A first end of the cylindrical member 202 
has a rectangular plate member 204 fastened thereto. Plate member 204 lies 
in a plane orthogonal to the major cylindrical axis of cylindrical member 
202. A second end of the cylindrical member 202 has a pair of cam surfaces 
206 and 208 formed thereon. As shown in FIG. 2, cam surface 206 is a 
planar surface that is essentially orthogonal to the magazine top surface 
102. As seen in FIG. 4, cam surface 208 is a planar surface that is 
angularly inclined with respect to the magazine top surface 102. At its 
second end near cam surface 208, the top of the cylindrical member is 
slightly beveled as at 209 to be essentially parallel with the horizontal. 
The cylindrical member 202 and the rectangular plate member 204 comprising 
the feed assist carriage 200 have an aligned aperture extending 
therethrough which loosely accommodates the guide rod 108, whereby the 
feed assist carriage 200 is translatable to and fro along the guide rod 
108 in the input transport direction indicated by arrow 42. The 
rectangular plate member 204 of the carriage 200 has a pin 210 anchored 
therein. A first end of a biasing spring 212 securely engages pin 210. A 
second end of the biasing spring 212 securely engages a similar pin 214 
anchored in the envelope guide wall 104, with the result that biasing 
spring 212 tends to pull the feed assist carriage 200 toward a blunt stop 
end 216 of the envelope guide wall 104. The stop end 216 of envelope guide 
wall 104 serves as a stop for limiting the degree of travel of the feed 
assist carriage 200 in the direction which is the reverse of the input 
transport direction 42. 
As shown in FIGS. 2 and 3, the feed assist means 80 has a plurality of 
envelope-contacting rollers provided thereon. In particular, the feed 
assist means features roller pair 220A and 220B mounted on vertical post 
221; roller pair 222A and 222B mounted on vertical post 223; roller pair 
224A and 224B mounted on vertical post 225; and, roller pair 226A and 226B 
mounted on vertical post 227. The posts 221, 223, 225, and 227 are held 
aloft by affixation near their midpoints to a cross beam 230. Each roller 
is rotatable on its respective post, but is held captive thereon by 
retaining rings, such as retaining rings 232A and 232B shown on post 227 
in FIG. 3. Cross beam 230 is anchored into rectangular plate member 204 of 
the feed assist carriage 200, and is retained therein by set screws 234. 
Near its midpoint, the cross beam 230 of the feed assist carriage 200 is 
supported by a vertical leg 240 that has a wheel 242 rotatably mounted at 
the distal end thereof. Wheel 242 rides on the input magazine top surface 
102. 
A feeder switch 244 is positioned so that a feeler arm 245 thereof can ride 
on cam surface 206 of the feed assist carriage 200 under normal operating 
conditions, i.e. when the feeder 72 should be intermittently feeding 
envelopes 86 toward the singulator gap 78. The feeder switch 244 is 
connected by line 246 to the signal controller 190. The signal controller 
190 is connected by line 247 and 248 to the feeder motor 142 and to the 
roller motor 156, respectively. 
The assist displacement control means 84 comprises means for changing the 
degree of pressure bearing against the feed assist means 80, and in 
particular comprises switch carriage means 250. As shown in FIGS. 2 and 4, 
switch carriage 250 is an essentially rectangular block 252 that carries a 
switch 254 on support bracket 256. Switch 254 is carried on carriage 250 
so that a feeler arm 258 included in the switch 254 can ride on the cam 
surface 208, or on the beveled top surface 209 of the feeder assist 
carriage 200. The switch 254 is connected by electrical line 260 to the 
motor 118 of the input transport means 110. 
As mentioned before, the guide rod 108 extends from post 106A near the 
entrance to the input magazine 70 to post 106B near the rear of the 
apparatus. Post 106B also carries a rear end of second guide rod 262. A 
front end of second guide rod 262 is anchored in the envelope guide wall 
104 near stop end 216 thereof. As shown in FIG. 4, the second guide rod 
262 is directly beneath, but considerably lower in elevation than, the 
guide rod 108. The feed assist carriage 200 rides sufficiently aloft on 
the guide rod 108 so that the second guide rod 262 poses no obstacle for 
the movement of the carriage 200. 
The rectangular block 252 of the switch carriage 250 has apertures provided 
therein for receiving the upper guide rod 108 and the lower guide rod 262, 
and for permitting the rectangular block 252 to translate in the 
directions shown by double-headed arrow 264. 
Near its top, the rectangular block 252 of switch carriage 250 has a 
channel 266 formed therein. The channel 266 is bridged by a cross member 
268. The cross member 268 has a clevis 270 rotatably secured thereto. A 
distal end of the clevis 270 is anchored in a first side of a coupling 
block 272. A second side of the coupling block 272 is connected to an 
output piston 274 of a stepper motor 276. The output piston 274 of stepper 
motor 276 is of the type that extends and retracts in the direction of 
arrow 264 in accordance with signals produced by the stepper motor 276. 
The stepper motor 276 is mounted on the post 106B. The post 106B has an 
aperture formed therein to accommodate the output piston 274 of stepper 
motor 276, so that the output piston 274 can connect to the coupling block 
272. As shown in FIG. 2, input terminals of the stepper motor 276 are 
connected by line 278 to output ports of the signal controller 190. Line 
278 carries signals thereon which dictate whether the output piston 274 of 
stepper motor 276 is to extend or retract, and thus whether the switch 
carriage 250 is to travel toward or away from the input magazine 70. 
It will be seen hereinafter that the assist displacement control means 84, 
including the switch carriage 250 and the input transport means 110 
connected thereto, serves to control the displacement of the feed assist 
means 80 by changing the degree of pressure bearing against the feed 
assist means 80. The signal controller 190 determines whether the position 
of the feed assist means 80 should be changed by examining the time 
elapsed since the last feed of an envelope through the singulator region 
73. If that elapsed time exceeds a predetermined time, the stepper motor 
276 retracts the switch carriage 252. With retraction of the switch 
carriage 252, the motor 118 of the input transport means 110 is energized, 
with the result that envelopes are further advanced toward the feed assist 
means 80, thereby pushing the feed assist means 80 further in the 
direction of the input transport direction 42. 
The feeder 72' of the embodiment of FIG. 9 differs from the feeder 72 of 
the embodiment of FIG. 2 in several respects. Unlike the roller 134 of the 
FIG. 2 embodiment, roller 134' of FIG. 5 does not have a fixed vertical 
axis about which it rotates. Rather than being anchored to the surface 
102, the vertical axis 280 of roller 134' is freely suspended above the 
surface 102, with the result that the entire assembly comprising rollers 
132', 134', and endless belt 130', can pivot or swing about vertical axis 
282 in the direction of arrow 284. The pivoting of the feeder assembly in 
this manner results from the force vector occassioned by the revolution of 
endless belt 130'. Accordingly, the belt 130' swings beyond its former 
position (shown as plane 286 in FIG. 9) and toward the leading envelope in 
the input magazine 70. 
The feeder 72' of the embodiment of FIG. 9 also further includes biasing 
means 288 for biasing the roller 134' so that the axes 282 and 280 of 
rollers 132' and 134' are in the plane (plane 290 being parallel to plane 
286). The biasing means 288 includes a bracket 292 upon which roller 134' 
is rotatably mounted. Bracket 292 is urged toward a vertical post 293 by a 
spring 294. 
The feeder 72' of the embodiment of FIG. 9 also includes means for limiting 
the degree of pivotal motion of the feeder 72' away from plane 286. In 
this regard, the bracket 292 carries an adjustment screw 295 thereon. The 
head of adjustment screw is aligned with a vertical stop member 296. The 
size of the gap 297 separating the head of adjustment screw 295 and the 
stop member 296 when the feeder 72' is braked is equal to the maximum 
component (along the direction of input transport) of the displacement of 
feeder 72' from the plane 286. Thus, distance 297 equals distance 298. 
STRUCTURE: STACKER SECTION 
As shown in FIG. 5, the stacker section 38 of the envelope processing 
system comprises a discharge magazine 300; introductory conveying means 
302; stacker conveying means 304; and, means 306 for displacing a trailing 
edge of a flat article. The stacker section 38 of the envelope processing 
system is downstream from the processing/transport section 24 to receive 
envelopes transported on-edge thereto by the transport system 62 of the 
processing/transport section 24. FIG. 5 shows how the horizontal belt 64 
and the vertical belts 66 and 68 of the transport section 62 transport 
belts toward the stacker section 38. 
The stacker section 38 has a horizontal stacker floor surface 310 which is 
at substantially the same elevation as both the feeder magazine surface 
102 of the feeder section 40 and the plane of the upper course of travel 
of the horizontal belt 64 of the processing/transport section 24. As will 
be described hereinafter, the introductory conveying means 302 and the 
stacker conveying means 304 of the stacker section 38 are primarily 
positioned above the stacker floor surface 310, with driving elements 
thereof being located beneath the surface 310. 
The discharge magazine 300 comprises a magazine floor 320; magazine 
abutment means 322; and, article discharge transport means 324. The 
discharge magazine floor 320 is co-planar with the stacker floor surface 
310. The magazine abutment means 322 is vertically mounted on the magazine 
floor 320 along the left-most edge thereof as seen in FIGS. 5 and 6, and 
thus has an axis of elongation 325 that extends parallel to the direction 
of discharge transport as indicated by arrow 45. 
The discharge magazine abutment means 324 carries two vertically upstanding 
posts, particularly posts 326A and 326B (only post 326B being illustrated 
in FIGS. 5 and 6. Posts 326A and 326B function in analogous manner to 
posts 106A and 106B of the feeder section 40, i.e., to hold aloft a 
horizontal guide rod. Thus, posts 326A and 326B hold aloft guide rod 328. 
As described hereinafter, guide rod 328 serves essentially the same type 
of function as does guide rod 108 of the feeder section 40, and in 
particular serves as a guide for compression plate 330. 
As shown in both FIGS. 5 and 6, the discharge magazine abutment means 322 
is an elongated plate member which has a first exterior wall 332 and a 
second exterior wall 334, both exterior walls 332 and 334 extending 
parallel to the axis of elongation 325. As shown in FIGS. 5 and 6, the 
first exterior wall 332 faces toward the right and is contactable by 
envelopes, while the second exterior wall 334 faces toward the left. The 
exterior walls 332 and 334 define an elongated central cavity 336 
therebetween, which, as best shown in FIG. 6, is filled with acoustic 
insulation material. 
As also shown in FIG. 6, the first exterior wall 332 of the magazine 
abutment means 322 has a plurality of parallel, horizontally extending 
ridges 340 along the length thereof. As described hereinafter, the ridges 
340 of the exterior wall 332 are contactable by envelopes being 
transported in the discharge magazine 330 and serve as bearing points to 
decrease frictional drag between the envelope edges and the abutment means 
322. 
The article discharge transport means 324 of the discharge magazine 300 
resembles the input transport means 110 of the feeder section 40. In this 
regard, the discharge transport means 324 comprises three transport belts 
342A, 342B, and 342C which have upper courses of travel that lie 
essentially in, or just above, the plane of the magazine floor 320. 
Although the drive mechanism of the transport belts 340 is not fully 
shown, it should be understood that, like the belts 112A, 112B, 112C of 
feeder section 40, the transport belts 342A, 342B, 342C, entrain pulleys 
that are commonly driven by motor 343. Moreover, the belts 342A, 342B, 
342C, like the belts 112A, 112B, 112C, are elastomeric timing belts having 
teeth 344 provided thereon at regularly spaced intervals. 
As mentioned above, the compression plate 330 of the stacker section 38 
travels along the guide rod 328 in like manner as compression plate 124 
travels along guide rod 108. To this end, the compression plate 330 has a 
sleeve 345 which fits over and is rotatable about the guide rod 328. When 
in its natural orientation, the bottom edge of the compression plate 330 
rides on the transport belts 342 for travel away from the stacker section 
38 in the direction depicted by arrow 45. The compression plate 330 thus 
forms a surface against which a sidewall of a first flat article, once it 
is discharged from the stacker section 38, can vertically contact. 
The introductory conveying means 203 of the stacker section 38 comprises 
two pairs of revolving vertically oriented O-rings, particularly 
introductory front rings 350A and 350B and introductory rear rings 352A 
and 352B. The introductory front rings 350A and 350B are each entrained 
about vertically upstanding pulleys 354 and 356, while the introductory 
rear rings 352A and 352B are each entrained about vertically upstanding 
pulleys 358 and 360. 
As shown in FIGS. 6 and 7, the O-ring pair 350A, 350B is entrained about 
the same pulley 354 as is the front vertical belt 66 of the 
processing/transport section 24. To accommodate the common entrainment, 
belt 66 extends around a midportion of the pulley 354, while the O-ring 
350A extends around a top portion of the pulley 354 and the O-ring 350B 
extends around a bottom portion of the pulley 354. The O-ring pair 352 is 
similarly entrained along with rear vertical belt 68 on the pulley 358. 
Although not shown, it should be understood that pulleys 354 and 356 are 
continuously driven by motors in the same manner as are other pulleys and 
rollers described herein, which motors are positioned beneath the stacker 
floor surface 310. 
As shown in FIG. 5, the pulleys 356 and 360 are so positioned that the 
O-ring pairs 350, 352 direct flat articles travelling on-edge therebetween 
along a linear introductory path indicated by broken line 360. As seen 
from above in FIG. 5, the linear introductory path 360 is oriented at an 
acute angle 362 with respect to the direction (indicated by arrow 44) of 
transport through the processing/transport section 24. The O-ring pairs 
350, 352 comprising the introductory conveying means 302 thus direct 
articles travelling on-edge therebetween so that a leading edge of each 
article contacts the stacker conveying means 304. 
The stacker conveying means 304 includes a pair of stacker belts 370A, 370B 
which serve to direct articles travelling on-edge to the discharge 
magazine 300. Each stacker belt 370A and 370B extends around a trio of 
vertically upstanding rotatable pulleys 372, 374, and 376. The stacker 
belt 376 is rotatably driven in the clockwise direction by virtue of its 
connection (via belt 377) to motor 378. Accordingly, the pulleys 374 and 
376 also rotate in the clockwise direction, and the stacker belts 370 
travel in the clockwise sense about the pulleys they entrain. 
Each of the pulleys 372, 374, and 376 are mounted on the stacker floor 
surface 310, so that their axes of rotation are perpendicular to the floor 
surface 310. As shown in FIG. 7, stacker belt 370A extends around a top 
portion of the pulleys while stacker belt 370B extends around a top 
portion of the pulleys, thereby providing a gap 379 between the stacker 
belts 370A and 370B. 
As shown in FIG. 5, the pulleys 372, 374, and 376 are positioned so that 
the stacker belts 370 acquire an essentially triangular course of travel 
about the pulleys. As part of this triangular course of travel, the 
stacker belts 370 direct articles delivered thereto along a first linear 
path segment (indicated by broken line 380) toward a midsection, such as 
midsection 382 of envelope 384A, of a previously stacked article in 
discharge magazine 300. As used herein, the midsection of an article means 
a section of the article proximate the pulley 374 after the article has 
just been stacked in the discharge magazine 300. As shown in FIG. 5, the 
first linear path segment 380 formed by the stacker belts 370 extends 
between pulleys 372 and 374, and is oriented at an obtuse angle 386 with 
respect to the linear introductory path 360 provided by the introductory 
conveying means 302. 
As another part of the triangular course of travel, the stacker belts 370 
define, between pulleys 374 and 376, a second linear path segment 
(indicated by broken line 388). As shown in FIG. 5, the second linear path 
segment 388 is oriented at an obtuse angle 390 with respect to the first 
linear path segment 380. The first linear path segment 380 and the second 
linear path segment 388 intersect at a bend point 391. At bend point 391 
the tangent of the stacker belts 370 relative to pulley 374 is essentially 
orthogonal to the direction of discharge conveyance 45. 
As described hereinafter, when a flat article such as an envelope is 
conveyed by the stacker belts 370, the leading edge of the article is 
initially directed along the first linear path segment 380 to the 
midsection 382 of a previously stacked article. Upon reaching midsection 
382 and pulley 374, the leading edge of the article bends through the 
obtuse angle 390 as the article becomes interposed between the stacker 
belts 370 and the previously stacked article, by virtue of the stacker 
belts 370 directing the article along the second linear path segment 388. 
As the leading edge of the article is so bent around the pulley 374, the 
trailing edge of the article is displaced through the angle 392, with the 
result that the trailing edge of the article essentially "fishtails" away 
from the first linear path segment 380. 
The fishtailing, or angular displacement, of the trailing edge of a flat 
article in the manner just described is further facilitated by positioning 
element 394. Positioning element 394 is a rotatable element having a major 
axis of rotation 396. The axis of rotation 396 extends parallel to the 
axis of elongation 325 of the abutment means 322, and hence is essentially 
parallel to the discharge direction indicated by arrow 45. The axis of 
rotation 396, as seen in FIG. 6, is just slightly beneath the floor 320 of 
the discharge magazine 300. The floor 320 of the discharge magazine 300 
has an elongated slot formed therein to accommodate the positioning 
element 394. 
The axis of rotation 396 of the rotatable element 394 is separated by a 
distance 400 from the axis of elongation 325 of the abutment means 322. 
Since the axes 396 and 325 are parallel, the distance 400 is understood to 
be the perpendicular distance between those two axes. The bend point 391 
is separated from the axis of elongation 325 of the abutment means 322 by 
a distance 402. As shown in FIG. 5, the distance 400 is greater than the 
distance 402, which means that the axis of rotation 396 of the positioning 
element 394 is separated from the axis of elongation 325 of the abutment 
means 322 by a greater distance than is the midpoint 382 of a flat article 
at the bend point 391. 
The positioning element 394 includes a first portion 394A and a second 
portion 394B. The first portion 394A has exterior threads 404 thereon 
which extend slightly above the plane of the magazine floor 320 to engage 
bottom edges of flat articles. The second portion 394B has a plurality of 
chord-like surfaces 406A, 406B, and 406C formed on the exterior thereof. 
Between the chord-like surfaces 406 are provided arcuate surfaces 408A, 
408B, and 408C. When the chord-like surfaces 406 are parallel to the 
magazine floor 320, the surfaces 406 essentially lie in the plane of the 
magazine floor 320. However, when the chord-like surfaces 406 are not 
parallel to the magazine floor 320, the arcuate surfaces 408 on the 
periphery of the second portion 394B extend slightly above the plane of 
the magazine floor 320. As shown in FIG. 6, when an arcuate surface 408 
extends above the plane of the magazine floor 320, the bottom edge of a 
flat article resting thereon is displaced, or slightly elevated, above the 
magazine floor 320 through an angle 410. Elevating an article in this 
manner permits the leading edge of the article to fall by gravity toward 
the abutment means 322 for better registration thereagainst. 
The positioning element 394 rotates about its axis of rotation 396 by 
virtue of its connection to a rotating shaft of motor 414. As shown in 
FIG. 5, motor 414 is located beneath the magazine floor 320. 
The positioning element 394 is situated closer to the bend point 391 than 
are the discharge transport belts 342. That is, with respect to the 
direction of discharge as depicted by arrow 45, the distance 416 
separating the positioning element 394 from the bend point 391 is less 
than the distance 418 separating the discharge belts 342 from bend point 
391. Thus, the first portion 394A of the positioning element 394 is 
optimally located to engage trailing edges of flat articles as the 
articles are interposed between a previous article in the stack and the 
stacker belts 370 along the second linear path segment 388. 
As mentioned above, the gap 379 is provided between the stacker belts 370A 
and 370B. The gap 379 is sized to accommodate the O-ring 352A of the 
introductory conveying means which, as shown in FIG. 5, must extend into 
the interior of the triangular course of travel of stacker belts 370. 
The stacker section 38 also includes a stack sensor means 420 for 
controlling the discharge transport means 324, particularly the transport 
belts 342. The stack sensor means 420 comprises a horizontal sensor lever 
arm 422 that is carried by a vertically upstanding pivot post 424. Pivot 
post 424 is mounted on the stacker floor surface 310 so that the lever arm 
422 can pivot thereabout. The lever arm 422 has a first end 422A and a 
second end 422B. The first end 422A of the sensor lever arm is resiliently 
biased in the counter-clockwise direction with respect to pivot post 424 
by virtue by biasing means 426. In the illustrated embodiment, biasing 
means 426 is a spring having a first end which engages the first end 422A 
of the sensor lever arm and a second end which is secured to a vertically 
upstanding stationary post 428. The biasing means 426 serves to urge the 
sensor lever arm 422 in the counter-clockwise direction away from a 
microswitch 430. Microswith 430 is connected by an unillustrated 
electrical lead to the, drive motor 343 for the discharge transport belts 
342A, 342B, 342C. Stop member 430 provides a limit to the extent of 
counter-clockwise rotation about the pivot post 424. 
The second end 422B of the sensor lever arm extends through the gap 379 
provided between the stacker belts 370A and 370B in the vicinity of the 
second linear path segment 388. The distal end of the end 422B thus bears 
against the rear sidewall of the flat article most recently interposed 
between a previous article and the stacker belts 370. When a sufficient 
number of flat articles are stacked in the discharge magazine 300, the 
articles exert sufficient force on the second end 422B of the sensor lever 
arm to cause the sensor lever arm 422 to rotate in the clockwise direction 
about the pivot post 424. If this clockwise force is great enough, the 
first end 422A of the sensor lever arm will overcome the bias exerted by 
the spring 426, and will contact the microswitch 430. When so contacted, 
the microswitch 430 sends an electrical signal to activate the discharge 
transport drive motor 343. When activated, the discharge, transport drive 
motor 343 causes the transport belts 342A, 342B, 343C, carrying flat 
articles and the compression plate 330 thereon to be transported further 
in the discharge direction as depicted by arrow 45. 
The abutment means 322 of the stacker section 38 has a stripper means 440 
provided thereon at its end proximate the pulley 376. As shown in FIG. 5, 
the stripper means 440 is a foot-like member which projects beyond the 
plane of the first exterior wall 332 of the abutment means 322. The 
foot-like stripper member 440 extends between the stacker belts 370A and 
370B and into the gap 379. The stripper member 440 thus serves to preclude 
a leading edge of a flat article from being further conveyed by the 
stacker belts 370 around the pulley 376. 
STRUCTURE: PRINTHEAD MOUNT ASSEMBLY 
FIGS. 15A and 15B show a printhead mount assembly 500 according to an 
embodiment of the invention. The printhead mount assembly 500 is located 
at the bar code printer 54 station along the processing-transport section 
24. The printhead mount assembly 500 functions to lock the printhead 501 
of the ink jet printer into a predetermined position suitable for the 
printing operation. 
The printhead mount assembly 500 includes an anchor block 502; a bottom 
clamp member 504; and, a top clamp member 506. The anchor block 502 is 
securely fastened to a predominately planar horizontal surface 508 by two 
fasteners 510. 
The bottom clamp member 504 has two yoke legs 512 which straddle the anchor 
block 502. A pivot rod 514 having threaded ends extends through aligned 
apertures in the anchor block 502 and the yoke legs 512. Lock nuts 516 are 
provided on each threaded end of the pivot rod 514. When the lock nuts 516 
are loosened, the bottom clamp member 504 can pivot about the pivot rod 
514. Tightening the nuts 516 locks the position of the bottom clamp member 
504 relative to the anchor block 502. 
A tongue 520 of the top clamp member 506 extends downwardly into a space 
formed between the two yoke legs 512 of the bottom clamp member 504. The 
tongue 520 is positioned between the two yoke legs 512 by virtue of the 
extension of a pivot rod 522 through aligned apertures in the two yoke 
legs 512 and the tongue 520. Like pivot rod 514, the pivot rod 522 has 
threaded ends which receive lock nuts 524. As is understandable by the 
analogous description above of the pivot rod 514, the pivot rod 522 
facilitates pivotal motion of the top clamp member 506 with respect to the 
bottom clamp member 504. 
The bottom clamp member 504 has a central region 530 which has an 
essentially truncated, flat-bottomed "V"-shape, as seen in FIG. 15B. The 
flat bottom of the central region 530 extends below the surface 508 into a 
mating channel suitably shaped to receive region 530. The interior of the 
"V"-shaped central region 530 is partially curved to receive the bottom of 
the cylindrically-shaped printhead 501. 
A distal portion 534 of the bottom clamp member 504 has a pair of 
compression springs 536 sandwiched between the underside thereof and the 
horizontal surface 508. At its furtherest extreme, the distal portion 534 
carries a vertical adjustment means 540. The vertical adjustment means 540 
includes an adjustment bolt 542 which extends through the distal portion 
534; through a plastic collar 544; and, into the horizontal surface 508 
where it is threadingly anchored. A threaded lock nut 546 is carried on 
the shaft of the adjustment bolt 542. Movement of the lock nut 546 
selectively controls the altitude of the lower clamp member 504, and of 
the entire printhead mount assembly 500, above the surface 508. 
The top clamp member 506 has a central portion 550 which overlies the 
printhead 501 clamped therebeneath. A distal portion 552 of the top clamp 
member 506 carries both a set screw 554 and a fastener 556. A first end of 
the fastener 556 is anchored into the upper surface of the distal portion 
of the lower clamp member 504. A second end of the fastener 556 carries a 
wing nut 558. The set screw 554 has a distal end which bears against the 
upper surface of the distal portion of the lower clamp member 504. 
Adjustment of the adjustment bolt 542 of the vertical adjustment means 540 
controls the height of the bottom clamp member 504 with respect to the 
surface 508. In this respect, adjustment of the bolt 542 permits the 
bottom clamp member 504 to pivot about the axis of the pivot rod 516. 
Adjustment of the set screw 554 controls the height of the top clamp 
member 506 relative to the bottom clamp member 504. In this respect, 
adjustment of the set crew 554 permits the top clamp member 506 to pivot 
about the axis of the pivot rod 522. 
As shown in FIG. 15B, the top clamp member 506 has a registration mark 560 
provided thereon to facilitate the angular orientation of the printhead 
501. In this respect, when the printhead is in a correct position, a 
corresponding mark on the printhead lines up with the registration mark 
560 provided on the top clamp member 506. In this manner, after the 
printhead 501 has been removed and serviced, the proper angular 
positioning of the printhead 501 can rapidly be reacquired. 
STRUCTURE: READ WINDOW 
FIGS. 13A-13C show a read window assembly 570 utilized in conjunction with 
the reader means 50 along the processing/transport section 24. The read 
window 570 includes a vertical base member 572 which is anchored to the 
planar horizontal surface 508 by fasteners 574. The vertical base member 
572 has a narrow, elongated slot or "read window" 576 formed therein. 
At its top, the vertical base member 572 carries a block 578 and a top 
extension 579. The block 578 and flange 579 are slightly angled with 
respect to the vertical as shown by angle 580. Block 578 has a slot formed 
therein for a purpose described below, and accomodates a thumb screw 582 
having a shank oriented towards the slot. 
A narrow spring steel plate or slide 584 slidably extends behind the 
vertical base member 572 and through the slot formed in the block 578. The 
bottom portion of the plate 584 is extruded, or "dimpled" as seen from 
above in FIG. 13C, to fit into the read window 576. The spring steel plate 
584 is captivated in the block 578 as the thumb screw 582 bears against 
the plate 584 in the slot of the block 578. Captivity of the plate 584 by 
the block 578 causes the slide to assume an angular orientation at the top 
of the vertical base member 572. The spring steel plate 584 is painted 
white. At its very top, the spring steel plate 584 has an outwardly-turned 
flange 585 provided thereon. 
The top extension 579 of the vertical member 572 has indicia 586 of 
increments of scale provided therealong. The alignment of the top flange 
585 of the plate 584 with a particular indicia 586 of the increments of 
scale reflects the distance from the bottom edge of an on-edge envelope to 
the bottom edge 590 of the plate 584 (that is, the height 592 of the read 
window as shown in FIG. 13B). 
The extruded or dimpled shape of the plate or slide 584 in the read window 
576 serves to eliminate shadows which otherwise could be erroneously 
interrpreted by the read device as characters. The angular orientation of 
the slide or plate 584 about the angle 580 advantageously eliminates any 
collision between the slide 584 and envelopes in transit. 
STRUCTURE: READ WINDOW SET-UP GUIDE 
The read window set-up guide 600 of the embodiment of FIG. 14 is 
advantageously provided to assist in the set-up of the read window 
assembly 570 of FIGS. 13A-13C. In this regard, the read window set-up 
guide 600 provides the operator with a simple and quick manner of 
determining where the top flange 585 of the slide 584 should be positioned 
relative to the indicia scale 586 for a certain address field on an 
envelope. 
The read window set-up guide 600 is stored behind the keyboard 32, but for 
use is slidable from out behind the keyboard 32 to assume the appearance 
shown in FIG. 14. The read window set-up guide 600 comprises a 
transparent, essentially rectangular plastic member 602 mounted on a 
support shelf 604. The plastic member 602 has a horizontal scale 606 and a 
vertical scale 607 provided along bottom and left edges thereof, 
respectively. 
The support shelf 604 also carries a stationary post 608. A sleeve 609 
extends over the post 608 and has a horizontal, opaque plate 610 attached 
thereto, so that the plate 610 extends over the plastic member 602 and 
parallel to the horizontal scale 606 formed at the bottom edge of the 
plastic member 602. The width of the opaque plate 610, i.e. the extent of 
the plate along the vertical horizontal scale 607, corresponds to the 
extent of vertical scan of the particular reader employed in the system. 
The positioned of the opaque plate 610 relative to the post 608 is 
selectively lockable by virtue of thumb screw 612. The opaque plate 610 
carries an arrow-shaped indicator 614 which slides along the plate 610 in 
the horizontal direction. 
The read window set-up guide 600 is operated in conjunction with the read 
windown assembly 570 in the following manner. An envelope having the 
address field positioning for a batch is positioned behind the transparent 
plastic member 602 of the read window set-up guide 600. The arrow-shaped 
indicator 614 is moved to the position of the zip code field in the 
envelope address. The opaque plate 610 is slid along post 608 so that the 
plate 610 covers the address field. Numbers on the vertical scale 606 and 
the horizontal scale 607 can be used to move the top flange 585 of the 
sliding spring steel plate 584 of the read window assembly 570 into 
corresponding alignment with suitable indicia 586. 
OPERATION: FEEDER SECTION 
In operation, motors 142 and 156 are turned on ("energized") and envelopes 
86 are placed on-edge on the transport belts 112. With motor 156 
energized, rollers 75 and 157 continuously rotate in the clockwise 
direction. The size of the first stage singulation gap 142 is preset by 
manipulating the adjustment screw 155 of the biasing means 152 of the 
first stage singulator means 74. The compression plate 124 is translated 
along guide rod 108 to a point whereat the envelopes 86 are snuggly 
compressed in a stack between the compression plate 124 at the rear end of 
the stack and the feeder 72 and the feed assist device 80 at the front end 
of the stack. With feed assist carriage 200 in a normal operating 
position, the signal on line 246 from feeder switch 244 causes the signal 
controller 190 to send signals on line 192 to the clutch/brake mechanism 
138 associated with the feeder 72. The signal prompts the clutch/brake 
mechanism 138 to allow the feeder belt 130 to revolve clockwise around 
rollers 132 and 134. 
Revolution of feeder belt 130 directs the foremost envelope 86A in the 
input transport section 24 in the direction of arrow 88 by imparting 
momentum to the envelope 86A upon contact of the revolving belt 130 with 
the envelope sidewall. The envelope is thus directed to the singulation 
region 73. 
In the singulation region 73, the envelopes first pass through the first 
stage singulation gap 142 defined by the first stage singulation means 74 
and the feeder 72. As an envelope approaches the first stage singulation 
means 74, the envelope first contacts the roller 150. If the envelope is a 
thicker envelope than that contemplated upon presetting the first stage 
singulation gap 142, contact with the roller 150 causes the lever arm 146 
to back away from the feeder 72. That is, the envelope drives lever arm 
146 in the direction opposite the direction depicted by arrow 42, thereby 
widening the first stage singulation gap 142. Thus, contact of roller 150 
by an envelope can serve to displace the stones 144A, 144B, and thus 
temporarily redefine the first stage singulation gap 142 for thick 
envelopes. 
Upon leaving the first stage singulation gap 142, the leading edge of an 
envelope heads toward the second stage singulation gap 143 defined by the 
rotating pull-out roller 75 and roller 76. The rotating pull-out roller 75 
imparts further momentum to the envelope 86, directing the envelope 86 
further in the direction of arrow 88 and into the nip of continuously 
rotating roller 157 and roller 158. 
When the leading edge of an envelope blocks beam 178 between transmitter 
174 and receiver 176 just upstream from the roller pair 150, 152, receiver 
176 sends a signal on line 186 to signal controller 190. Upon receipt of 
such signal on line 186, the signal controller 190 applies a signal on 
line 192 to the clutch/brake mechanism 138 for stopping the motion of 
feeder belt 130. This braking of feeder belt 130 precludes the immediate 
feeding of a further envelope, and thus facilitates a slight delay and 
spacing between envelopes. 
Continuously rotating roller 157 directs an envelope 86 further downstream 
toward transport system 62. As mentioned before, transport system 62 
includes revolving horizontal belt 64 and vertical belts 66 and 68. Since 
the axes 157' and 158' of the rollers 157 and 158 are inclined at angle 
alpha with respect to the vertical (as shown in FIG. 10), the rollers 157 
and 158 direct the envelope with a downward component so that the envelope 
86 registers on the horizontal belt 64. The belts 64, 66, and 68 included 
in the transport system 62 carry the envelope 86 through the 
processing/transport section 24 in the direction of arrow 44. 
The signal controller 190 turns the clutch/brake mechanism 138 back on at a 
predetermined time after beam 178 is interrupted. In the illustrated 
embodiment, the predetermined time is 1/5 second. 
Upon emerging from the nip between rollers 157 and 158, the leading edge of 
envelope 86 blocks beam 184 between transmitter 180 and receiver 182. When 
beam 184 is thusly blocked, a signal on line 188 is applied to the signal 
controller 190. The signal controller 190 examines the frequency of the 
interruptions of beam 178 to determine whether the feeder 72 is having 
difficulty in feeding the next envelope. For example, at a given speed of 
the roller 75, the signal controller knows how many envelopes should 
interrupt beam 178 every second. If the controller 190 determines that 
difficulty is experienced by the feeder 72, the signal controller 190 
applies a signal on line 278 to the feed assist means, and more 
particularly to the assist displacement control means 84. 
The signal on line 278 from the signal controller ultimately serves to 
retract the feed assist means 80 in the direction 42 so that, as shown in 
FIGS. 11A and 11B, the feeder belt 130 of feeder 72 can better contact the 
next envelope 86 for driving the next envelope in the direction of arrow 
88 toward the singulation region 73. In particular, a signal on line 278 
serves to displace the feed assist means 80 from its normally biased 
position as shown in FIG. 11A (wherein the tangent plane T to feeder belt 
130 is essentially coplanar to a common tangent plane T' to each of the 
rollers 220, 222, 224, and 226) to a displaced position such as that shown 
in FIG. 11B (whereat the common tangent plane T' is displaced in the 
direction of arrow 42 from the tangent plane T). 
The feed assist means 80 is displaced to a position such as that shown in 
FIG. 11B in the following manner: The signal applied on line 278 causes 
the output shaft 274 of stepper motor 276 to retract toward post 106B. The 
retraction of output shaft 274 causes rectangular block 252, and switch 
254 carried thereon, to move further toward the left as shown in FIG. 4. 
The signal controller 190 continues to apply signals on line 278 until the 
leftward movement of switch 254 moves feeler arm 258 out of contact with 
the cam surface 208 of the feed assist carriage 200. The switch 254 then 
applies a signal on line 260 to activate the input transport motor 118. 
Activation of motor 118 drives pulleys 114A, 114B, and 114C, with the 
result that belts 112A, 112B, and 112C are incrementally advanced in the 
direction of arrow 42. As the belts 112A, 112B, 112C advance, so do the 
envelopes 86 and the compression plate 124 carried thereupon. Advancement 
of the envelopes 86 and compression plate 124 in the direction of arrow 42 
causes the stack of envelopes 86 to bear with increasing pressure against 
the feeder belt 130 and feed assist means 80 (particularly against the 
rollers 220, 222, 224, and 226 which the lead envelope contacts) until the 
bias of spring 212 is overcome. When the bias of spring 212 is overcome, 
the entire feed assist carriage 200 is displaced in the direction of arrow 
42, with the result that tangent plane T' is no longer co-planar with 
tangent plane T (see FIG. 11A). When the feed assist carriage 200 is 
sufficiently retracted so that feeler arm 258 of switch 254 again contacts 
cam surface 208, the switch 254 applies a signal on line 260 to deactivate 
the input transport motor 118, and thereby temporarily stop advancement of 
the belts 112A, 112B, 112C. 
With belts 112A, 112B, 112C stopped and feeder 72 still feeding, pressure 
against the feed assist means 80 decreases, with the result that the feed 
assist carriage 200 is pulled by bias spring 212 toward its normal biased 
position. In moving toward its normally biased position, feed assist 
carriage 200 may again lose contact with the feeler arm 258 of switch 254, 
causing switch 254 to again activate advancement of the transport belts 
112A, 112B, 112C, and thus the envelope stack, toward the feeder 72 and 
the feed assist means 80. Pressure then again increases on the feed assist 
means 80, so that the feed assist means 80 is displaced sufficiently that 
the feeler arm 258 again rides on cam surface 206 of carriage 200. At that 
point, the input transport belts 112A, 112B, 112C again cease 
incrementation. 
The feed assist means 80 including the feed assist carriage 200 thus can 
continuously linearly roam from and return to its normally biased position 
(which is the furthest extent of its permitted travel toward the input 
envelope stack), depending on the pressure bearing against the feed assist 
means 80. As disclosed above, when the signal controller 190 determines 
that the feeder 72 is having difficulty in feeding a next envelope, the 
assist displacement control means 84 facilitates the further displacement 
of the feed assist means 80 by increasing pressure in the envelope input 
section. Thus, acting through the assist displacement control means 84, 
the signal controller 190 attempts to overcome difficulties encountered in 
feeding an envelope, such as a thick envelope, by requiring an increase in 
pressure against the feed assist means 80, thereby necessitating greater 
displacement of the feed assist means 80 from its normally biased 
position, and thereby facilitating enhanced driving force on the difficult 
envelope. Accordingly, as shown with respect to FIGS. 11A and 11B, the 
greater the difficulty encountered in feeding an envelope, the greater the 
distance becomes between tangent planes T and T'. 
If the feed assist means 80 is displaced so far from the tangent plane T 
such that the feeding of doubles occur, the signal controller 190 will 
detect the feeding of doubles and ultimately cause the feed assist means 
80 to travel back toward the tangent plane T. In this regard, the feeding 
of doubles causes the detector beam 178 to be blocked for a time period 
longer than that permitted by the signal controller 190. The signal 
controller 190 detects the abnormally long blockage of beam 178, knowing 
the maximum length of an envelope and the peripheral speed of the pull-out 
roller 75. When an abnormally long blockage occurs, the signal controller 
190 sends a signal on line 278 to extend the output shaft 274 of the 
stepper motor 276 away from post 106B. As understood with reference to the 
foregoing description of the retraction of output shaft 274, the extension 
of shaft 274 causes the feed assist device to travel in the direction 
opposite that depicted by arrow 42 (i.e., back towards the tangent plane 
T). 
The operation of the embodiment of FIG. 9 resembles the operation described 
above, except that, upon revolution of belt 130', roller 134' essentially 
kicks belts 130' out of plane T, such that the tangent plane T' of belt 
134' is displaced by angle beta as shown in FIGS. 9 and 12. Pivotal 
movement of the feeder belt 130' in this manner causes the application of 
greater force to the foremost envelope in the input stack. Upon braking of 
the feeder 72, the roller 134' resumes its normal positions, as shown by 
tangent plane T. 
OPERATION: STACKER SECTION 
After being processed along the processing path 26 of the 
processing/transport section 24, an envelope is directed on-edge by the 
horizontal belt 64 and vertical belts 66, 68 of section 24 toward the 
introductory conveying means 302. The path of travel of an envelope E 
thorough the stacker section 38 is represented by FIGS. 8A-8E, which are 
frames representing successive stages of the path of travel. 
Upon leaving the processing/transport section 24, as shown in FIG. 8A the 
envelope E encounters the O-ring pairs 350, 352 which comprise the 
introductory conveying means 302. As the leading edge of the envelope E 
contacts the front O-rings 350A, 350B, and then the rear O-rings 352A and 
352B, the leading edge of the envelope E is deflected from direction 44 
about the acute angle 362, so that the envelope travels along the linear 
introductory path 360. 
FIG. 8B shows how the introductory conveying means 302 directs the leading 
edge of the envelope E along the linear introductory path 360 and toward 
the stacker conveying means 304, and particularly to the stacker belts 
370. FIG. 8B also shows that the leading edge of the envelope E contacts 
the stacker belts 370. 
FIG. 8C shows how the stacker conveying means 304 directs the envelope E on 
its edge along the first linear path segment 380 toward the discharge 
magazine 300. The stacker belts 370 comprising the stacker conveying means 
304 thus deflect the envelope E about the obtuse angle 386 between the 
linear introductory path 360 and the first linear path segment 380, so 
that the leading edge of the envelope E is now headed toward the discharge 
magazine 300. In particular, the envelope E is now headed toward the bend 
point 391 and thus toward the mid-section 382 of a previously-stacked 
envelope 384A. 
FIG. 8D shows how the stacker conveying means 302 interposes the envelope E 
between the previously stacked envelope 384A and the stacker belts 370. 
After the leading edge of the envelope E is deflected around the obtuse 
angle 390 at the bend point 391, the leading edge of envelope E commences 
its travel along the second linear path segment 388. The bending of the 
envelope E at the bend point 391, as the envelope E is interposed between 
the stacker belts 370 and the previously stacked envelope 384, causes the 
trailing edge of the envelope E to be displaced through the acute angle 
392, so that the trailing edge essentially "fishtails" out of the path of 
the next envelope E'. 
This displacement of the trailing edge of the envelope E is facilitated by 
the positioning element 394, and particularly the helically threaded first 
portion 394A thereof. In particular, the bottom of the trailing edge of 
the envelope E is engaged to ride in the helical threads 404 of the 
rapidly rotating positioning element 394, so that the element 394 serves 
to quickly propel the trailing edge of the envelope along the direction of 
arrow 45, even before the envelope E encounters the discharge belts 342 
and while the leading edge of the envelope E is heading up the second 
linear path segment 388. Indeed, with the trailing edge of the envelope E 
experiencing a component of motion in the direction of arrow 45, and the 
leading edge having a component of motion in the opposite direction (i.e., 
back up to pulley 376), it is understood how the fishtailing is 
facilitated. After its trailing edge is displaced through the acute angle 
392, the envelope E then regains its linear profile which, as illustrated 
in FIG. 8E, is colinear with the second linear path segment 388. 
It should be noted that the length of the first linear path segment 380 is 
sufficiently long such that, when the trailing edge of an envelope E is 
displaced or fishtailed through the angle 392, the trailing edge of 
envelope E does not strike the pulley 356, i.e. does not cross the linear 
introductory path 360. 
FIG. 8E further shows how the envelope E settles in the stack formed by the 
discharge magazine 300. In particular, envelope E is situated so that as 
its front sidewall contacts the previously stacked envelope 384A, its rear 
sidewall contacts the moving stacker belts 370. The leading edge of 
envelope E then abuts the magazine abutment means 322. Stripper member 440 
formed on the abutment means 322 precludes the leading edge of envelope E 
from travelling further along with the stacker belts 370, so that the 
envelope E is retained in the discharge magazine. 
As the envelope E strikes the abutment means 322, what would otherwise be 
an audiably noticeable popping sound is muffled by the acoustic insulation 
material 338 provided in the internal cavity 336 of the abutment wall 322. 
FIG. 8E also shows what happens when the discharge magazine 300 becomes 
sufficiently loaded with envelopes, i.e., when enough envelopes become 
interposed between the stacker belts 370 and the compression plate 330 
that the discharge transport belts 342 need to be activated to carry the 
envelopes and compression plate 330 further away from the stacker section 
38 in the direction of arrow 45. The stack of envelopes in the magazine 
300, acting through the rear sidewall of envelope E, exerts sufficient 
force F on the second end 422B of the sensor lever arm to cause the sensor 
lever arm to pivot in the clockwise sense about the pivot post 428. If the 
force F is sufficiently great to overcome the bias on the first end 422A 
of the sensor lever arm provided by the spring 426, the first end 422A of 
the sensor lever arm will trip the microswitch 430. When the microswitch 
430 is so tripped, the microswitch 430 sends an electrical signal to 
activate the discharge transport drive motor 433. When activated, the 
discharge transport drive motor 433 drives pulleys and the discharge 
transport belts 342 entrained thereabout, so that the belts 342 and the 
envelopes and compression plate 330 riding thereon are transported further 
away from the stacker section 38 in the direction depicted by arrow 45, 
with the result that the stack becomes less tight for accommodating 
further envelopes. 
As the envelopes stacked in the discharge magazine 300 are transported away 
from the stacker section 38 in the direction of arrow 45, the leading 
edges thereof contact the ridges 340 provided on the magazine abutment 
wall 322. The ridges 340 essentially serve as bearing points to reduce the 
frictional drag between the envelopes and the abutment wall 322, with the 
result that envelopes are less susceptible to snagging or jamming in the 
magazine 300. 
The positioning element 394 also continues to optimally position the 
envelopes in the discharge magazine 300. The second portion 394B of the 
element, also being rotatably driven, periodically elevates the bottom 
edges of envelopes riding thereon so that the envelopes become properly 
registered against the abutment wall 322. In this regard, and as shown in 
FIG. 6, when the chord-like surfaces 406 of the element 394 are parallel 
with the horizontal, the element 394 is substantially planar with the 
magazine floor 320. However, when the arcuate surfaces 408 of the member 
394 are positioned to protrude through the slot 398 formed in the magazine 
floor 320, the bottom edges of the envelopes are elevated, with the result 
that the bottom edges of the envelopes become inclined at the angle 410 
with respect to the magazine floor 320. 
While the invention has been particularly shown and described with 
reference to the preferred embodiments thereof, it will be understood by 
those skilled in the art that various alterations in form and detail may 
be made therein without departing from the spirit and scope of the 
invention.