Note: Descriptions are shown in the official language in which they were submitted.
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Description
NON-MARKING ACCUMULATOR AND RELATED METHODS
The present application was divided out of Canadian Patent Application
Serial No. 2,418, 881 filed February 12, 2003.
Technical Field
The present invention is generally directed to the field of document
handling and processing technology and, in particular, to improvements
relating
to the accumulation of material units.
Background Art
A recurring problem in document handling operations is toner smudging
or marking, which most often occurs as the result of the necessary interaction
between document handling components and material units containing printed
matter being handled by those components. The problem of toner smudging is
especially acute and pervasive in document accumulation operations. In
conventional accumulation configurations, a single-level accumulator drives
material into and over entrance ramps with the use of o-rings (also known as
polycords) that are continuously moving in the direction of material flow.
These
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continuously moving o-rings contact each face (i.e., the front andlor the back
side) of the material. The material is first driven, as separate pieces or a
pair,
into the accumulator from an upstream device. The material is then advanced
to the exit end of the accumulator by the o-rings that are essentially
designed to
act as a slip drive and comes to rest as the lead edge of the material
contacts a
pair of output rollers. Subsequent pages then accumulate over or under each
preceding piece until the accumulator's maximum capacity is reached (usually
10-15 sheets) or a full set is satisfied. The o-rings, however, continue to
cycle
as material comes to rest and as succeeding material enters the accumulator
and begins to accumulate. Accordingly, toner smudge occurs as, for example,
the bottom set of o-rings becomes impregnated with toner from preceding
pieces and transfers this toner to the first page of the set as it rests in
the static
condition.
Examples of document handling devices such as accumulators that
employ pressure-applying belts or o-rings to drive sheets are disclosed in
U.S.
Patent Nos. 6,203,006; 5,915,686; 5,794,931; 5,775,689; 5,692,745;
5,655,761; 5,647,587; 5,590,873; 5,484,255; 5,244,200; 5,147,092; and
4,767,115.
Material removal can also be problematic in conventional accumulator
devices. Material must be folded and often torn to be removed from between
the fixed o-rings of the accumulator. Another problem relates to the
stretching
of o-rings over time due to wear and material removal. Moreover, material
justification can be problematic, particularly when accumulating before a
folder.
To achieve a high quality fold with minimal shingling, a set of material that
is
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square on all edges (front, back, and both sides) optimizes the fold quality.
Other recurring issues include the ease with which an accumulator device can
be changed from over-accumulation to under-accumulation, and can be
adjusted to accommodate different material sizes, if such switchirig
capabilities
are provided at all.
The present invention is provided to address, in whole or in part, these
and other problems associated with prior art document handling technology.
Disclosure of the Invention
The invention disclosed herein provides a sheet accumulating apparatus
and method for accumulating sheets. A series of single sheets, or a series of
accumulated or stacked subsets of sheets, are inputted into an accumulation
section. The apparatus is operable in either an over-accumulation mode or an
under-accumulation mode. In the over-accumulation mode, each new sheet of
subset of sheets enfers the accumulation section on top of the developing
stack of sheets in the accumulation section. In the under-accumulation mode,
each new sheet of subset of sheets enters the accumulation section
underneath the developing stack of sheets in the accumulation section. In
either mode, the apparatus is constructed and its components selected and
arranged so as to minimize contact or engagement between sheets and
physical structure, and to enhance the control of the apparatus over the speed
and flow of the sheets through the apparatus. Therefore, smudging of printed
matter on the sheets and damage to the sheets are minimized. Moreover, the
apparatus facilitates rapid adjustment by the user between the over-
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accumulation and under-accumulation modes without the need for tools. In
addition, the sheets accumulating in the accumulation section are registered
on
all four sides, i.e., lead edge, trail edge, and lateral edges. Consequently,
a
predetermined number of sheets are accumulated into a fully registered stack
for advancement to a location downstream of the apparatus.
According to one embodiment, a sheet accumulating apparatus
comprises an accumulation section defining a sheet feed plane therethrough.
An upper ramp is disposed upstream from the accumulation section and is
movable into and out of the sheet feed plane. An upper retaining member is
linked to the upper ramp and is movable into and out of the sheet feed plane
in
alternating relation to the upper ramp. A lower ramp is disposed below the
upper ramp and is movable into and out of the sheet feed plane in alternating
relation to the upper ramp. A lower retaining member is linked to the lower
ramp and movable into and out of the sheet feed plane in alternating relation
to
the upper ramp.
Preferably, the upper ramp, the upper retaining member, the lower ramp,
and the lower retaining member are pivotably movable into and out of the sheet
feed plane, the upper ramp is pivotable in an opposite direction in relation
to
the pivoting of the upper retaining member, and the lower ramp is pivotable in
an opposite direction in relation to the pivoting of the lower retaining
member.
Preferably, the mechanical interface or functional couplings among the
corresponding ramps and retaining members are implemented with linkages.
Accordingly, in one embodiment, an upper linkage links the upper ramp to the
upper retaining member and a lower linkage links the lower ramp to the lower
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retaining member. The upper linkage comprises a first upper linkage member
pivotable with the upper ramp and a second upper linkage member pivotable
with the upper retaining member in engagement with the first upper linkage
member. The lower linkage comprises a first lower linkage member pivotable
with the lower ramp and a second lower linkage member pivotable with the
lower retaining member in engagement with the first lower linkage member.
Even more preferably, the linkage members include respective toothed portions
that engage each other, such that the linkage members can comprise
intermeshing gears or gear segments.
In some embodiments, a front stop mechanism is disposed downstream
from the upper and lower ramps and is movable into and out of the sheet feed
plane.
In some embodiments, a carriage assembly is movably engaged with a
frame of the accumulating apparatus and supports the front stop mechanism.
Accordingly, the front stop mechanism is movable with the carriage assembly
toward and away from the upper and tower ramps, thereby enabling the
accumulating apparatus to accommodate different lengths of sheets.
Preferably, the accumulating apparatus comprises a sheet transport
device. The sheet transport device comprises one or more sheet-engaging
members, such as pusher fingers or lugs, that are rrrovable through the
accumulation section along the sheet feed plane. Such a sheet transport
device is employed to at least begin transport of a stack of over- or under-
accumulated sheets out from the accumulating section of the apparatus. The
sheet-engaging members contact only the trail edge of the sheet stack and
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thus do not cause smudging. Hence; even with the use of the sheet transport
device, sheets are still not subject to any moving components while
accumulation is occurring.
Preferably, the accumulating apparatus comprises left and right side
jogging members disposed at respective lateral sides of the accumulation
section. These side jogging members are movable toward and away from each
other along a direction transverse to a sheet flow path through the
accumulation section. Alternating actuation or other movement of the side
jogging members jogs the sheets into side-by-side registration in the
accumulation section.
According to another embodiment, a sheet accumulating apparatus :.
comprises an accumulation section defining a sheet feed plane therethrvugh,
and an accumulating assembly disposed upstream from the accumulation
section. The accumulating assembly is selectively adjustable to an over-
accumulation position and an alternative under-accumulation position. The
accumulating assembly comprises a first ramp, a first retaining member, and a
first linkage interconnecting the first ramp and the first retaining member,
wherein the first ramp is movable with first retaining member. The
accumulating assembly also comprises a second ramp, a second retaining
member, and a second linkage interconnecting the second ramp and the
- second retaining member, wherein the second ramp is movable with the
second retaining member. At the over-accumulation position, the first ramp
and the second retaining member are disposed out of the sheet feed plane,
and the second ramp and the first retaining member extend in the sheet feed
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plane. At the alternative under-accumulation position, the first ramp and the
second retaining member extend in the sheet feed plane, and the second ramp
and the first retaining member are disposed out of the sheet feed plane. The
sheet accumulating apparatus is thus structured so as to be adjustable to
either
accumulation position, and consequently is capable of either over-accumulating
or under-accumulating sheets as desired by the end user.
According to yet another embodiment, a sheet accumulating apparatus
comprises upper and lower frame sections, first and second upper rotatable
members, upper and lower accumulation ramps, upper and lower sheet guide
members, and first and second lower rotatable members. The upper frame
section has an upper input end and the lower frame section has a lower input
end, such that the upper and lower input ends define an input area and a sheet
feed plane therebetween and the sheet feed plane extends through the input
area. The first upper rotatable member is disposed in the upper frame section
and the second upper rotatable member engages the first upper rotatable
member, such that rotation of the first upper rotatable member in one
direction
corresponds to rotation of the second upper rotatable member in an opposite
direction. The upper accumulation ramp is connected to the first upper
rotatable member and is rotatable therewith into and out. of the sheet feed
plane. The upper sheet guide member is connected to the second upper
rotatable member and is rotatable therewith into and out of the sheet feed
plane. The first lower rotatable member is disposed in the lower frame sectioh
and the second lower rotatable member engages the first lower rotatable
member, such that rotation of the first lower rotatable member in one
direction
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corresponds to rotation of the second lower rotatable member in an opposite
direction. The lower accumulation ramp is connected to the first lower
rotatable
member and is rotatable therewith into and out of the sheet feed plane. The
lower sheet guide member is connected to the second lower rotatable member
and is rotatable therewith into and out of the sheet teed plane.
According to still another embodiment, a sheet accumulating apparatus
comprises upper and lower frame sections, a plurality of elongate upper and
lower sheet guides, and upper and lower accumulation ramps. The upper
frame section has an upper end and the lower frame section has a lower end,
such that the upper and lower frame sections define an accumulation area
therebetween. The upper end pivotably engages the lower end to enable the .
upper section to pivot away from the lower section and thus to provide access
to the accumulation area. The elongate upper sheet guides are supported by
the upper frame section and are pivotable therewith, and define an upper
boundary of the accumulation area. The elongate lower sheet guides are
supported by the lower frame section and define a lower boundary of the
accumulation area. The upper accumulation ramp is supported by the upper
frame section and is pivotable therewith. The lower accumulation ramp is
supported by the lower frame section.
According to a further embodiment, a material accumulating apparatus
comprises a frame assembly, an input section, a carriage assembly, and a front
stop mechanism. The frame assembly comprises first and second lateral
support plates. The input section is disposed at an upstream region of the
frame assembly and defines a material flow path running between the first and
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second lateral support plates. The carriage assembly comprises a front stop
support plate extending between the first and second lateral support plates, a
first carriage member movably connecting the frorit stop support plate to the
first lateral support plate, and a second carriage member movably connecting
the front stop support plate to the second lateral support plate. The front
stop
mechanism is disposed downstream from the input section and is mounted to
the front stop support plate. Translation of the front stop support plate
along a
general direction of the material flow path varies a distance between the
front
stop mechanism and the input section.
Preferably, the front stop mechanism comprises a front stop member
and an actuator connected to the front stop member, and the front stop
member is movable by the actuator into and out of the material flow path. It
is
also preferable that the front stop member be spring-mounted so as to provide
a recoiling action upon contact with an incoming sheet and thus assist in
registering sheets from lead edge to trail edge. It is further preferred that
the
accumulating apparatus comprise a first rack gear mounted to the first lateral
support plate, a second rack gear mounted to the second lateral support plate,
a first pinion gear fixedly disposed in relation to the first carriage member
and
engaging the first rack gear, and a second pinion gear fixedly disposed in
relation to the second carriage member and engaging the second rack gear.
By this configuration, rotation of the first and second pinion gears
respectively
along the first and second rack gears causes translation of the first and
second
carriage members respectively along the first and second rack gears.
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In some embodiments, the invention comprises upper and lower output
rollers fixedly mounted in relation to the front stop mechanism and
translatable
therewith.
According to a yet further embodiment, a material accumulating
apparatus comprises a sheet input device, an accumulation area disposed
generally downstream from the sheet input device, a front stop mechanism
disposed downstream from the sheet input device, first and second output
rollers disposed at a fixed distance downstream from the front stop mechanism,
_
and a material transport device. The sheet input device comprises a first
input
roller and a second input roller. A material feed plane is defined between the
first and second input rollers. The accumulation area comprises a plurality of
upper guide rods and a plurality of lower guide rods, such that the material
feed
plane is disposed between the upper and lower guide rods. The front stop
mechanism comprises a front stop member and an actuator connected to the
front stop member. The front stop member is movable by the actuator into and
out of the material feed plane. The material transport device comprises
movable material-engaging lugs between the first and second input rollers and
the first and second output rollers.
According to a still further embodiment, a material accumulating
apparatus comprises a frame assembly, an input section disposed at an
upstream region of the frame assembly, a side jogging mechanism disposed
downstream from the input section, and a front stop mechanism disposed
downstream from the input section. The frame assembly comprises first and
second lateral support plates. The input section defines a material flow path
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running between the first and second lateral support plates. The side jogging
mechanism comprises an upstream support rod extending between the first
and second lateral support plates, a downstream support rod extending
between the first and second lateral support plates, first and second mounting
brackets, first and second side guides respectively linked to the first and
second mounting brackets, and first and second actuating devices. Each
mounting bracket has an upstream end slidably supported by the upstream
support rod and a downstream end slidably supported by the downstream
support rod. The first and second actuating devices are respectively adapted
to translate the first and second side guides along a direction transverse to
the
material flow path. The front stop mechanism is mounted to the front stop
support plate. Translation of the front stop support plate along a general
direction of the material flow path varies a distance between the front stop
mechanism and the input section.
According to other embodiments, the accumulating section comprises a
plurality of upper elongate members and a plurality of lower elongate members.
The sheet feed plane is defined between the upper and lower elongate
members. Preferably, the upper and lower elongate members are cylindrical in
cross-section so as to provide the minimum possible contact area for sheets
that encounter the elongate members.
A method is also provided for registering one or more sheets during or
after accumulation of the sheets in an accumulating apparatus, according to
the following steps. An accumulation section is provided that defines a sheet
feed plane. A front stop is moved into the sheet feed plane. A back stop is
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moved into the sheet feed plane at a position upstream from the front stop. A
sheet is moved along an input path past the back stop into the accumulation
section, whereby the sheet contacts the front stop and is recoiled thereby
toward the back stop. The sheet is alternately translated along opposing
directions transverse to the input path. Preferably, the sheet is moved past
the
back stop by contacting the sheet with an inclined surface of the back stop,
whereby the sheet is at least temporarily diverted away from the sheet feed
plane to move around the back stop. The sheet is alternately translated
preferably by alternately moving left and right opposing side guides toward
and
away from a centerline of the accumulation section.
A method is also provided for adjusting an accumulating apparatus :.
between an over-accumulating mode and an under-accumulating mode,
according to the following steps. An accumulating section is provided that
defines a sheet feed plane extending therethrough. An accumulating assembly
is generally disposed upstream from the accumulating section and comprises
an upper ramp, an upper retaining member movably linked to the upper ramp;
a lower ramp, and a lower retaining member movably linked to the lower ramp.
An over-accumulating mode is set by causing the upper ramp to move out of
the sheet feed plane whereby the upper retaining member moves into the
sheet feed plane, and causing the lower ramp to move into the sheet feed
plane whereby the lower retaining member moves out of the sheet feed plane.
The under-accumulating mode is an alternative setting. The under-
accumulating mode is set by causing the upper ramp to move into the sheet
feed plane whereby the upper retaining member moves out of the sheet feed
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plane, and causing the lower ramp to move out of the sheet feed plane
whereby the lower retaining member moves into the sheet feed plane.
According to another method, sheets are over-accumulated according to
the following steps. An accumulating section is provided that defines a sheet
feed plane extending therethrough. An accumulating assembly is generally
disposed upstream from the accumulating section and comprises an upper
retaining member and a lower ramp, wherein the upper retaining member and
the lower ramp extend into the sheet feed plane. An incoming sheet is moved
generally along the sheet feed plane toward the lower ramp. The incoming
sheet is caused to contact the lower ramp and move over the lower ramp. The
incoming sheet is caused to contact the upper retaining member and be guided
downwardly thereby, whereby the incoming sheet enters the accumulating
section between the upper retaining member and a preceding sheet residing in
the accumulating section.
According to yet another method, sheets are under-accumulated
according to the following steps. An accumulating section is provided that
defines a sheet feed plane extending therethrough. An accumulating assembly
is generally disposed upstream from the accumulating section and comprises
an upper ramp and a lower retaining member, wherein the upper ramp and the
lower retaining member extend into the sheet feed plane. An incoming sheet is
moved generally along the sheet feed plane toward the upper ramp. The
incoming sheet is caused to contact the upper ramp and move below the upper
ramp. The incoming sheet is caused to contact the lower retaining member
and be guided upwardly thereby, whereby the incoming sheet enters the
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accumulating section between the lower retaining member and a preceding
sheet residing in the accumulating section.
According to a further method, sheets are over-accumulated according
to the following steps. A first sheet is inputted along a sheet feed plane
toward
an accumulation area. The first sheet is diverted above the sheet feed plane.
The first sheet is urged downwardly as the first sheet moves into the
accumulation area, and comes to rest in the accumulation area. A second
sheet is inputted along the sheet feed plane toward the accumulation area.
The second sheet is diverted above the sheet feed plane. The second sheet is
urged downwardiy as the second sheet moves into the accumulation area, and
comes to rest in the accumulation area on top of the first sheet. The method
can be repeated for subsequent sheets to form an accumulated stack of sheets
in the accumulation area.
According to an additional method, sheets are under-accumulated
according to the following steps. A first sheet is inputted along a sheet feed
plane toward an accumulation area. The first sheet is diverted below the sheet
feed plane. A trailing edge of the first sheet is urged upwardly as the first
sheet
moves into the accumulation area, such that the first sheet comes to rest in
the
accumulation area with its trailing edge elevated above the sheet feed plane.
A
second sheet is inputted along the sheet feed plane toward the accumulation
area. The second sheet is diverted below the sheet feed plane and below the
trailing edge of the first sheet. A trailing edge of the second sheet is urged
upwardly as the second sheet moves into the accumulation area: The second
sheet comes to rest in the accumulation area underneath the first sheet, and
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the trailing edge of the second sheet is elevated above the sheet feed plane.
The method can be repeated for subsequent sheets to form an accumulated
stack of sheets in the accumulation area.
It is therefore an object to provide an accumulating apparatus for
collecting and advancing sheet articles, and particularly such an apparatus
for
use in high-speed media processing.
It is another object to provide an accumulating apparatus that permits
selection and adjustment of either over-accumulating or under-accumulating of
the sheet articles processed thereby, and can also accommodate different
sheet sizes.
It is yet another object to provide an accumulating apparatus for
improved handling of processed sheet articles that eliminates or at least
greatly
minimizes toner smudging of smearing of the sheet articles.
It is still another object to provide an accumulating apparatus for
improved handling of processed sheet articles wherein the sheet articles are
accumulated into a fully registered set of sheets.
Some of the objects having been stated hereinabove and which are
achieved in whole or in part by this invention, other objects will become
evident
as the description proceeds when taken in connection with the accompanying
drawings as best described hereinbelow.
Brief Description of the Drawings
Figure 1 is a perspective view of an accumulating apparatus provided in
accordance with the present invention;
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Figure 2 is a side elevation view of an upstream region of the
accumulating apparatus illustrated in Figure 1;
Figure 3 is a perspective view of a portion of an accumulating assembly
provided with the accumulating apparatus illustrated in Figure 1;
Figure 4 is a side elevation view of an upstream region of the
accumulating apparatus illustrated in Figure 1, showing the apparatus
operating in an over-accumulating mode;
Figure 5 is a side elevation view of an upstream region of the
accumulating apparatus illustrated in Figure 1, showing the apparatus
operating in an under-accumulating mode;
Figure 6 is a side elevation view of a portion of the accumulating
apparatus illustrated in Figure 1, showing details of a transport device
provided
therewith;
Figure 7 is a perspective view of an upstream region of the accumulating
apparatus illustrated in Figure 1;
Figure 8 is a side elevation view of the accumulating apparatus
illustrated in Figure 1;
Figure 9 is a side elevation view in partial phantom of a front stop
mechanism;
Figure 10 is a perspective view of the front stop mechanism illustrated in
Figure 9;
Figure 11 is another perspective view of the front stop mechanism
illustrated in Figure 9;
Figure 12 is a perspective view of a carriage assembly;
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Figure 13 is a perspective view of a side-to-side jogging assembly;
Figure 14 is a side elevation view of one portion of the side-to-side
jogging assembly illustrated in Figure 13;
Figure 15 is a perspective view of the portion of the side-to-side jogging
assembly illustrated in Figure 14; and
Figure 16 is a perspective view of the accumulating apparatus illustrated
in Figure 1, wherein an upper section of the apparatus has been pivoted away
from a lower section thereof.
Detailed Description of the Invention
Referring now to Figure 1, an accumulating apparatus, generally
designated 10, is provided which is adapted to accumulate material without
smudging or otherwise marring any printed matter contained on either side of
the sheet material being processed. Accumulating apparatus 10 is also
adapted to produce an accumulated set of sheets that are properly registered
on all (leading, trailing, and lateral) edges. Moreover, accumulating
apparatus
10 is selectively adjustable between an over-accumulating mode of operation
and an under-accumulating mode of operation. These operational modes are
described in detail hereinbelow.
In general, accumulating apparatus 10 comprises an input section,
generally designated 15; an accumulation area, generally designated 20; and
an output section, generally designated 25. Arrow F in Figure 1 indicates the
general direction of material flow through accumulating apparatus 10. As
understood by persons skilled in the art, the various components comprising
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input section 15, accumulation area 20, and output section 25 are disposed in
relation to a framework assembly of accumulating apparatus 10. The
framework assembly can comprise a number of various structural members as
appropriate for assembling accumulating apparatus 10 into an integrated unit.
As shown in Figure 16, for example, the framework assembly can include
lateral support plates 30A and 30B. It will be further understood that
accumulating apparatus 10 can be situated in-line between upstream and
downstream modules as part of a larger material processing system. Non-
iimiting examples of upstream modules include feeders, cutters, readers,
folders, stagers, and turnover devices. Non-limiting examples of downstream
modules include readers, stagers, turnover devices, folders, inserters,
diverters,
envelope stuffers, postage meters, and finishers (e.g., stitchers, binders,
shrink
wrappers, or the-like).
In operation, accumulating apparatus 10 is initially set to perform either
over-accumulation or under-accumulation by manipulating outer thumb knobs
or levers 41A and 41B and inner thumb knobs or fevers 43A and 438, as
described in more detail hereinbelow. An upstream module or other means is
used to feed either individual sheets of material or subsets of sheets
sequentially into input section 15. Hence, as used hereinafter, the term
"sheet"
denotes either a single sheet or a subset of sheets, it being understood that
accumulating apparatus 10 is capable of producing an accumulated sheet set
from either a plurality of individually in-fed sheets or a plurality of in-
fed,
previously accumulated subsets of sheets. As a general matter, "sheets' can
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constitute any form of material units capable of being processed by document
handling equipment.
As described in more detail hereinbelow, input section 15 controls the
speed of the incoming sheets according to a dynamic speed profile as the
sheets are being fed into accumulation area 20. Once a sheet enters
accumulation area 20, that sheet is held while other sheets are permitted to
enter accumulation area 20 either under or over the first sheet. If
accumulating
apparatus 10 is set to over-accumulate sheets in accumulation area 20, the
first sheet entering accumulation area 20 becomes the bottom-most sheet in
the resulting stack of accumulated sheets. If, on the other hand, accumulating
apparatus 10 is set to under-accumulate sheets, the first sheet becomes the
top-most sheet in the resulting stack of accumulated sheets.
As sheets are accumulated in the accumulation area 20, the leading
edge, trailing edge, and lateral edges of each sheet are registered or
justified,
so that all sides of the resulting stack are squared off in preparation for
subsequent advancing of the sheet stack to a downstream site (e.g., a
downstream sheet set processing module). In at least one embodiment, an
adjustable front stop mechanism (described hereinbelow) is utilized to
register
the leading edge of each incoming sheet. In at least one other embodiment, a
jogging mechanism (described hereinbelow) is used to assist in registering the
lateral edges of the sheets in fhe accumulating stack. Once a predetermined
number of sheets have accumulated in accumulation area Z0, such as by
employing conventional sensing or counting means, a transport mechanism
(described hereinbelow) generally situated within accumulation area 20
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advances the stack into output section 25, from which the sheet set is
transported from accumulating apparatus 10 to the downstream site.
As shown in Figure 1, a set of top elongate support (or sheet guide)
members comprising rods 45 and a set of bottom elongate support (or sheet
guide) members comprising rods 47 extend through accumulation area 20, and
respectively define upper and lower structural boundaries for the set of
material
units accumulating in accumulation area 20. Preferably, two or more
corresponding pairs of top support rods 45 and bottom support rods 47 are
provided, with each pair being laterally spaced from adjacent pairs. Top and
bottom support rods 45 and 47 are passive elements. As such, top and bottom
support rods 45 and 47 do not impart active forces to the sheets, and thus do
not smudge the sheets. In furtherance. of the smudge-free operation of
accumulating apparatus 10, it is also preferable that top and bottom support
rods 45 and 47 be cylindrical so as to present the smallest possible contact
area for the sheets.
Referring to Figure 2, the material flow path indicated by arrow F through
accumulating apparatus 10 is directed generally along a central sheet feed
plane P. Central sheet feed plane P thus also indicates the general flow path
.. of sheets through accumulating apparatus 10, and further provides a general
demarcation between upper and lower sections of accumulating apparatus 10.
In Figure 2, upper section is generally designated 10A and lower section is
generally designated 108.
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Input section 15 (Figure 2) of accumulating apparatus 10 comprises an
entrance area, generally designated 49, defined at least in part by a top
entrance guide 51A disposed in upper section 10A of accumulating apparatus
above central sheet feed plane P and a bottom entrance guide 51 B
5 disposed in lower section 10B below central sheet feed plane P. Input
section
further comprises a dynamic in-feed mechanism, which preferably includes
a pair of dynamic in-feed rollers 53A and 53B. Top in-feed roller 53A is
disposed in upper section 10A of accumulating apparatus 10 above central
sheet feed plane P, and bottom in-feed roller 53B is disposed in lower section
10 10B below central sheet feed plane P. Hence, a nip is formed between top
and
bottom in-feed rollers 53A and 53B that is generally situated about central
sheet feed plane P.
The coupling of one of in-feed rollers 53A or 53B to a variable-speed
motor (not shown) renders the rollers "dynamic" in the sense that their
15 rotational speed is variable over a given range (for example, approximately
80
ips to approximately 180 ips, where °ips" denotes "inches per second").
For
each cycle, defined for the present purpose as a sheet being fed through input
section 15 and into accumulation area 20 (and accumulating over or under the
pre-existing stack, if any), the dynamic speed profile is characterized by an
initial input speed (preferably matched with the output speed of the upstream
module) followed by a vamping down of the speed as the sheet enters
accumulation area 20 and abuts the front stop mechanism provided. The ramp
of deceleration that forms a part of the dynamic speed profile can be
associated with a constant rate of deceleration or a non-linear rate. As one
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example, the initial in-feed speed can be 180 ips, which is thereafter
dynamically stowed down according to a predetermined speed profile to a lower
speed of 80 ips.
Input section 15 also comprises a switchable overlunder accumulating
mechanism that comprises the following components. First and second top
gears or gear segments 55A and 55B, respectively, are mounted in upper
section 10A of accumulating apparatus 10 above central sheet feed plane P,
and rotate about respective parallel axes in meshing engagement with each
other. Similarly, first and second bottom gears or gear segments 57A and 57B,
respectively, are mounted in lower section 10B of accumulating apparatus 10
below central sheet feed plane P, and rotate about respective parallel axes in
meshing engagement with each other. Thus, first and second top gear
segments 55A and 55B rotate in opposite senses with respect to each other,
and first and second bottom gear segments 57A and 57B rotate in opposite
senses with respect to each other. In a preferred embodiment, first top gear
55A and top in-feed roller 53A rotate about the same axis, and first bottom
gear
57A and bottom in-feed roller 53B rotate about the same axis.
The overlunder accumulating mechanism further comprises one or more
top accumulation ramps 59 and one or more bottom accumulation ramps 61.
Top accumulation ramps 59 are linked in mechanical relation to first top gear
segment 55A and rotate therewifh, and bottom accumulation ramps 61 are
linked in mechanical relation to first bottom gear segment 57A and rotate
therewith. As shown in Figure 2, top and bottom accumulation ramps 59 and
61 preferably include respective inclined surfaces 59A and 61A and back-stop
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surfaces 59B and 61 B. One or more top hold-down spring fingers 63 (see
Figure 4) are linked in mechanical relation to second top gear segment 55B
and rotate therewith, and one or more bottom top hold-down spring fingers 65
(see Figure 4) are linked in mechanical relation to second bottom gear segment
5TB and rotate therewith. The top hold-down spring fingers 63 and the bottom
hold-down spring fingers 65 are exemplary embodiments of upper and lower
retaining members linked to the top and bottom ramps 59 and 61 via respective
gear sets 55A, 55B, and 57A, 57B.
Preferably, top and bottom hold-down fingers 63 and 65 include
respective arcuate sections 63A and 65A as shown in Figure 4. Each arcuate
section 63A and 65A can be constructed as a continuous member or as a
contiguous series of differently angled segments. Each of top and bottom hold-
down fingers 63 and 65 is constructed of such physical dimensions and
material composition as to be capable of storing spring energy. Hence, top and
bottom hold-down fingers 63 and 65 are deflectable upon encountering a force
and recoverable to an initial profile upon subsequent removal of the force.
Inclined surfaces 59A and 61A of respective top and bottom accumulation
ramps 59 and 61, and arcuate sections 63A and 65A of respective top and
bottom hold-down fingers 63 and 65, selectively interact with incoming sheets
as described hereinbelow. The selectivity depends on whether the over-
accumulation mode or under-accumulation mode is active. As also described
hereinbelow, respective back-stop surfaces 59B and 61B of top and bottom
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i accumulation ramps 59 and 61 assist in selectively registering the trailing
edge
of the stack of sheets.
Referring to Figure 3, the mechanical arrangement of outer knobs 41A
and 41 B, first and second bottom gear segments 57A and 578, bottom
accumulation ramps 61, and bottom hold-down fingers 65 are illustrated in
accordance with a preferred embodiment of the invention. Each outer knob
41 A and 41 B is connected to its corresponding first bottom gear segment 57A
by one or more suitable fasteners 67, such that rotation of outer knobs 41Aand
41B likewise causes first bottom gear segments 57A to rotate. Each bottom
accumulation ramp 61 is connected to a support member 69 by one or more
suitable fasteners 71. Support member 69 is connected between outer knobs
41A and 41 B and thus rotates therewith. Each bottom hold-down finger 65 is
connected to another support member 73 by one or more suitable fasteners 75.
Support member 73 is connected between second bottom gear segments 57B
and thus rotates therewith. It will be understood that the mechanical
arrangement of inner knobs 43A and 43B (see Figure 1 ), first and second top
gear segments 55A and 55B (see Figure 2), top accumulation ramps 59, and
top hold-down fingers 63 (see Figure 4) can be analogously provided. Thus, in
Figure 1, top accumulation ramps 59 are connected to a support member 77,
which is in turn connected between inner knobs 43A and 43B and thus rotates
therewith. As shown in Figure 16. a support member 79 is also employed for
mounting top hold-down fingers 63 (Figure 4) in mechanical connection with
second top gear segments 55B.
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Referring back to Figure 2, the intermeshing of first and second top gear
segments 55A and 55B operatively couples top accumulation ramps 59 and
top hold-down fingers 63 together. Similarly, the intermeshing of first and
second bottom gear segments 57A and 578 (see also Figure 4) operatively
couples bottom accumulation ramps 61 and bottom hold-down fingers 65
together. As described hereinabove, inner thumb knobs 43A and 43B (see
Figure 1 ) mechanically communicate with first top gear segments 55A (see also
Figure 4) and second top gear segments 558 so as to effect adjustment of the
relative positions of top accumulation ramps 59 and top hold=down fingers 63.
Similarly, outer thumb knobs 41A and 41 B (see Figures 1 and 3) mechanically
communicate with first bottom gear segments 57A and second bottom gear
segments 57B so as to effect adjustment of the relative positions of bottom
accumulation ramps 61 and bottom hold-down fingers 65.
Figures 2 and 4 depict accumulating apparatus 10 in its over-
accumulating mode. Inner thumb knobs 43A and 43B (see Figure 1 ) are
pivoted to cause the coupling interaction of first and second top gear
segments
55A and 55B, top accumulation ramps 59 and top hold-down frngers 63. Outer
thumb knobs 41A and 41B (see Figures 1 and 3) are pivoted to cause the
coupling interaction of first and second bottom gear segments 57A and 57B,
bottom accumulation ramps 61 and bottom hold-down fingers 68. As a result,
and as shown in Figure 4, top accumulation ramps 59 are disposed in a raised
position out of the material flow path while, at the same time, top hold-down
fingers 63 are disposed in a lowered position in the material flow path. Also
at
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the same time, bottom accumulation ramps 61 are disposed in a raised position
in the material flow path while bottom hold-down fingers 65 are disposed in a
lowered position out of the material flow path. As described hereinbelow, this
configuration results in an over-accumulation of sheets in accumulation area
20.
Referring to Figure 5, accumulating apparatus 10 has been converted to
the under-accumulating mode by pivoting inner thumb knobs 43A and 43B and
outer thumb knobs 41A and 41 B to new positions. Top accumulation ramps 59
are now disposed in a lowered position in the material flow path, while top
hold-
down fingers 63 are disposed in a raised position out of the material flow
path.
At the same time, bottom accumulation ramps 61 are now disposed in a
lowered position out of the material flow path, while bottom hold-down fingers
65 are disposed in a raised position in the material flow path. As described
hereinbelow, this configuration results in an under-accumulation of sheets in
accumulation area 20.
Referring now to Figures 6 and 7; one or more dual-lugged transport
belts 81 A and 81 B are disposed atthe intertacial region of input section 16
and
accumulation area 20 of accumulating apparatus 10. Transport belts 81A and
81 B rotate about rotatable elements such as pulleys 83 and 85 mounted to
shafts 87 and 89; with one of shafts 87 and 89 being driven by a suitable
motor
(not shown). In a preferred embodiment, upstream-side pulleys 83 rotate about
the same axis as lower infeed rollers 538, and thus upstream-side shaft 87 can
be a common axle engaged by both upstream-side pulleys 83 and lower infeed
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rollers 53B. The inner surface of each transport belt 81A and 81B includes a
plurality of inside lugs 91 that engage ribbed pulleys 83 and 85 in order to
positively drive transport belts 81A and 81B. The outside surface of each
transport belt 81A and 81 B, likewise includes outside lugs 93 and 95 of
suitable
design (see Figure 6) for engaging the trailing edge of a sheet or sheets.
Suitable designs of such outside lugs 93 and 95 are known in the art. In one
exemplary embodiment, each transport belt 81A and 81B includes two outside
lugs 93 and 95 cyclically spaced 180 degrees apart from each other, with each
outside lug 93 and 95 of one transport belt 81A being situated in phase with
each corresponding outside lug 93 of the other transport belt 81 B. The upper
run of each transport belt 81A and 81 B is disposed at a high enough elevation
within accumulation area 20 so as to enable outside lugs 93 to contact the
trailing edge of the sheet stack residing in accumulation area 20, thereby
permitting transport belts 81A ancJ 81B to advance the sheet stack through
accumulation area 20 along the material flow path. In Figure 6, the positions
of
lugs 93 and 95 are designated 93A and 95A, respectively, at the moment
before lug 93A contacts a sheet stack.
Referring now to Figures 8-11, a front stop mechanism, generally
designated 110, is disposed gerieralfy within accumulation area 20. The
longitudinal position of front stop mechanism 110 with respect to input
section
15 is adjustable in order to accommodate different lengths of sheets. In
Figure
8, for example, front stop mechanism 110 is shown disposed at a position X at
which sheets of a relatively short length (e.g., 3.50 inches) can be
CA 02547302 2003-02-12
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accommodated, and is also alternatively shown disposed at a position Y at
which sheets of a relatively long length (e.g., 14.0 inches) can be
accommodated. Front stop mechanism 110 in a preferred embodiment
comprises spring-loaded, retractable front stop fingers 113. Front stop
fingers
113 are alternately extended across central sheet feed plane P (and thus in
the
material flow path) or retracted below central sheet feed plane P (and thus
out
of the material flow path). In Figure 8, for purposes of illustration, front
stop
fingers 113 are shown in the extended position at position X of front stop
mechanism 110 and in the retracted position at position Y of front stop
mechanism 110. It will be understood, however, that front stop fingers 113 are
alternately extendable and retractable during the operation of accumulating
apparatus 10 at all positions of front stop mechanism 110 available along the
length of accumulation area 20.
Referring to Figures 9 - 11, further details of the front stop mechanism
110 are shown. Each front stop finger or plate 113 is connected to a vertical
slide plate 115 using shoulder bolts 117 or other suitable securing means. A
compression spring 119 is interposed between each front stop finger 113 and
vertical slide plate 115 to enable each front stop finger 113 to recoil to a
degree
sufficient to jog sheets entering into the accumulation area 20, thereby
registering the sheets along their respective lead edges. Preferably,
compression springs 119 are generally axially aligned with central sheet feed
plane P (see Figure 8) when front stop fingers 113 are extended. Vertical
slide
plate 115 is connected to a guide plate 121 through one or more guide
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members 123A and 1238. Guide plate 121 is mounted to a support plate 125
by means of one or more suitable fasteners such as bolts 127. Guide
members 123A and 1238 are movable within respective slots 121A and 121 B
formed through guide plate 121 (see Figure 10) to enable vertical slide plate
115 to slide vertically with respect to guide plate 121. The interaction of
vertical
slide plate 115 with guide plate 121 thus enables front stop fingers 113 to
move
into and out of the material feed path as described hereinabove.
A powered drive source adapted for reversible rotary power transfer,
such as a rotary solenoid or reversible motor 131, is mounted to support plate
125 through a suitable mounting bracket 133 (see Figure 11 ) and includes an
output shaft 131A. An actuating arm 135 having a U-slot (designated 135A in
Figure 9) is connected to output shaft 131A, such that rotation of output
shaft
131 A clockwise or counterclockwise rotates actuating arm 135 in a like
manner.
Actuating arm 135 is linked to vertical slide plate 115 by means of'a
transverse
pin 137. Transverse pin 137 is secured to vertical slide plate 115 through one
or more suitable fasteners such as bolts 139. Transverse pin 137 is situated
within U-slot 135A of actuating arm 135, and thus is movable along the length
of U-slot 135A. Accordingly, rotation of actuating arm 135 in one direction
imparts an upward force to transverse pin 137 and results in vertical slide
plate
115 sliding upwardly, while rotation of actuating arm 135 in the other
direction
imparts a downward force to transverse pin 137 and results in vertical slide
plate 115 sliding downwardly.
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Referring back to Figure 8, one or more pairs of output rollers 141A and
141 B are associated with front stop mechanism 110. Top output roller 141 A is
disposed in upper section 10A of accumulating apparatus 10 above central
sheet feed plane P, and bottom output roller 141 B is disposed in lower
section
10B below central sheet feed plane P. Hence, a nip is formed between top.and
bottom output rollers 141A and 1418 that is generally situated about central
sheet feed plane P. In the case where a downstream material processing
device operates in connection with accumulating apparatus 10, the rotational
speed of output rollers 141A and 141 B is preferably matched to the speed of
the downstream device, which ordinarily is a constant speed falling within the
approximate range of, for example, 80 ips to 180 ips. Output rollers 141A and
141 B are disposed at a fixed distance downstream from front stop fingers 113,
yet are longitudinally adjustable with front stop fingers 113 along the length
of
accumulation area 20 to accommodate different sizes of sheets.
Referring now to Figure 12, a carriage assembly is illustrated that
enables the position of front stop mechanism 110 and its associated output
rollers 141 A and 141 B to be adjusted as described hereinabove. In Figure 12,
for purposes of clarity, only Power output rollers 141 B are shown with the
understanding that upper output rollers 141 A are also provided to form one or
more pairs of nip rollers (as shown in Figures 4, 5 and 8). In addition to the
front stop mechanism 110, output rollers 141 A and 141 B are also mounted to
support plate 125. A carriage member 151A and 1518 is secured to each
lateral end of support member 125. A pinion gear 153 traverses the full length
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of support plate 125 and 'has ends 153A and 1538 mounted within
corresponding carriage members 151A and 1518. Each pinion gearend 153A
and 1538 engages a respective rack gear 155A and 1558. This configuration
assists in maintaining the parallel/perpendicular positioning of front stop
mechanism 110. Each rack gear 155A and 1558 is respectively mounted to a
lateral support plate 30A and 308 (only one of which is shown in Figure 12).
Lateral support plates 30A and 308 form a part of the main frame assembly of
accumulating apparatus 10, as shown in Figure 16. The meshing between
pinion gear ends 153A and 1538 and their corresponding rack gears 155A and
1558 enable front stop mechanism 110 and output rollers 141A and 1418 to
translate back and forth together in a controlled manner, along the direction
of
material travel. This translational adjustment could be effected manually or
by
automated means. For example, the shaft position of pinion gear 153 could be
made to engage an appropriate motor and transmission asserribly so as to
transfer power to carriage members 151A and 151 B through the engagement
of pinion gear ends 153A and 1538 and rack gears 155A and 1558.
Outputrollers 141A and 141 B are driven by an output roller drive motor
161 and associated drive belt 163 and pulleys 165A, 1658 and 165C. The
position of this motor 161 is also adjustable with output rollers 141A and 141
B
and front stop mechanism 110. This is accomplished by mounting output roller
drive motor 169 to a sliding motor support plate 167. The lateral ends of
sliding
motor support plate 16T are connected to guide members 169 (only one of
which is visible in Figure 12) that slide along the lengths of respective side
rails
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171 A and 1 T1 B. Each side rail 171 A and 171 B is secured to a respective
lateral support plate 30A and 308 of accumulating apparatus 10.
Referring back to Figures 1 and 8, output section 25 of accumulating
apparatus 10 comprises one or more pairs of exit rollers 181 A and 1818. For
each pair of exit rollers 181A and 1818 provided, top exit roller 181A is
disposed in upper section 10A of accumulating apparatus 10 above central
sheet feed plane P, and bottom exit roller 181 B is disposed in lower section
108 below central sheet feed plane P (in Figure 1, only bottom exit rollers
181 B
are shown for clarity). Exit rollers 181A and 181 B form a nip that is
generally
situated about central sheet feed plane P. The speed of exit rollers 181A and
181 B is matched to that of output rollers 141 A and 141 B and thus to that of
the
downstream device.
Figures 13 -15 illustrate details of the side jogging mechanism provided
in accumulating apparatus 10. The side jogging mechanism includes two
adjustable side guides 191A and 191 B generally situated in accumulation area
20. Side guides 191A and 1918 function to guide sheets into and through
" accumulation area 20, as well as to laterally jog the sheets as they
accumulate
(o~ after a predetermined number of sheets have accumulated) in order to
register the side edges of the sheet stack. The respective lateral positions
of
side guides 191A and 1918 are adjustable with respect to the longitudinal
centerline of accumulation area 20 - that is, the centerline in the direction
of
material flow. Accordingly, as shown in Figure 13, each side guide 191A and
191 B is connected to a respective adjustable mounting bracket 193A and
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1938. In addition, the upstream ends of each adjustable mounting bracket
193A and 1938 are slidingly supported by a transversely disposed support rod
195, and the downstream ends of each adjustable mounting bracket 193A and
1938 are slidingly supported by another transversely disposed support rod 197.
The width between side guides 191A and 1918 can thus be varied to
accommodate different sheet sizes (e.g., a range of approximately 5.50 inches
to approximately 12.0 inches) by sliding adjustable mounting brackets 193A
and 1938 toward or away from each other along threaded support rods 195
and 197. The adjustment could be manual or mechanized in accordance with
known methods. Preferably, side guides 191Aand 191 B are initially positioned
equidistantly about the center line of accumulation area 20, and the width
between side guides 191A and 1918, for example, is approximately 0.25
inches greater than the actual width of the sheets to be processed to allow
room for side-to-side jogging.
As shown in Figures 14 and 15, each side guide 191A and 191 B is
connected to its respective adjustable mounting bracket 193A and 1938 by one
or more suitable linking members such as bolts 201Aand 201 B. Preferably, as
shown in Figure 15, two or more spaced bolts 201A and 201 B are employed to
improve the stability of side guides 191A and 191 B. As also shown in Figures
14 and 15, each side guide 191A and 191 B is biased laterally outwardly from
the centerline of accumulation area 20 by springs 203A and 2038. As shown
in Figure 14, each spring 203A and 2038 is retained on its corresponding bolt
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201A and 2018 between the head of bolt 201A and 2018 and a back plate
205A and 2058 of its corresponding side guide 191A and 191 B.
The jogging movement is effected by a suitable actuator such as a
solenoid 207A and 2078 mounted to each adjustable mounting bracket 193A
and 1938. The moving portion of each solenoid 207A and 2078, for example
an actuating arm 209, is able to contact back plate 205A and 2058 of each
corresponding side guide 191A and 191 B. Hence, activation of each solenoid
207A and 2078 causes extension of its actuating arm 209, and in turn causes
its side guide 191A and 1918 to translate inwardly toward the centerline of
accumulation area 20 against the biasing force of springs 203A and 2038.
Deactivation of each solenoid 207A and 2078 causes its side guide 191 A and v
191 B to return to its initial position under the influence of springs 203A
and
2038. Alternate activation and deactivation of solenoids 207A and 2078
produces the jogging action that results in side-to-side registration of
sheets in
accumulation area 20. The sheet stack can be jogged each time a new sheet
is added to the stack, or can be jogged affer the predetermined number of
sheets have been added to complete the stack. Preferably, the amount by
which each solenoid 207A and 2078 causes extension of its respective
actuating arm 209 depends on the initial width set between side guides 191A
and 191 B. For example, if the initial width is set to approximately 1/4
inches
greater than the actual width of the sheets being processed, the distance by '
which each actuating arm 209 extends can be 1/8 inches
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The operation of accumulating apparatus 10 when positioned in its over-
accumulation mode will now be described with reference to Figure 4. A stack S
of over-accumulated sheets is shown disposed between upper and lower
support rods 45 and 47, resting on bottom support rods 47 and supported (i.e.,
retained or held down) by top hold-down fingers 63. The leading edge of the
sheet stack is registered against front stop fingers 113 of front stop
mechanism
110, white the trailing edge of the sheet stack is registered against the
respective back surtaces of the bottom accumulation ramps 61. As described
hereinabove, the jogging action generated by the recoil of front stop fingers
113
as each sheet reaches sheet stack S assists in obtaining this front-to-back
registration of all sheets of sheet stack S. An incoming sheet IS is shown
being
fed through input section 15 to be accumulated over existing sheet stack S.
Top accumulation ramps 59 are in a raised position out of the material feed
plane, and thus out of the way of incoming sheet IS. Similarly, bottom hold-
down fingers 65 are in a lowered position out of 'the material feed plane, and
thus out of the way of incoming sheet IS. Bottom accumulation ramps 61 are in
a raised position in the material feed plane, such that the leading edge of
incoming sheet IS encounters their respective inclined front surfaces and is
thereby raised above the top side of the uppermost sheet jn the accumulating
stack S. Top hold-down fingers 63 are in a lowered position in the material
feed plane. Each incoming sheet IS flows over bottom accumulation ramps 61,
is guided downwardly by top hold-down fingers 63, is jogged by recoiling front
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stop fingers 113, and comes to rest on the top of stack S in registry between
front stop fingers 113 and bottom accumulation ramps 61.
The operation of accumulating apparatus 10 when positioned in its
under-accumulation mode will now be described with reference to Figure 5.
Stack S of under-accumulated sheets, or at least the trailing end region
thereof,
is held against top support rods 45 by bottom hold-down fingers 65. The
leading edge of sheet stack S is registered against front stop fingers 113 of
front stop mechanism 110, while the trailing edge of sheet stack S is
registered
against the respective back surfaces of top accumulation ramps 59. Top
accumulation ramps 59 are in a lowered position in the material feed plane,
such that the leading edge of incoming sheet IS encounters their respective
inclined front surfaces and is thereby directed downwardly underneath the
bottom side of the bottommost sheet in accumulating stack S. Bottom hold-
down fingers 65 are in a raised position in the material feed plane, and thus
support sheet stack S in a raised position and guide incoming sheets IS
upwardly to allow incoming sheets IS to accumulate underneath sheet stack S.
Bottom accumulation ramps 61 are in a lowered position out of the way of the
incoming sheets IS. Similarly, top hold-down fingers 63 are in a raised
position
out of the material feed plane, and thus out of the way of ancorning sheets IS
and accumulating stack S. Each incoming sheet IS flows along the inclined
front surfaces of top accumulation ramps 59 and between stack S and bottom
hold-down fingers 65, is jogged by recoiling front stop fingers 113, and comes
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to rest at the bottom of stack S in registry between front stop fingers 113
and
top accumulation ramps 59.
Referring now to Figure 16, according to an aspect of the invention, it
can be seen that upper section 10A of accumulating apparatus 10 includes an
upper frame 220 that is hinged or othenivise rotatably attached to lateral
support plates 30A and 30B of tower section 108 about pivot points 223A and
223B (e.g., pins or axles with appropriate mounting hardware). As shown in
Figures 2 and 4, upper section 10A comprises top entrance guide 51A, top
accumulation ramp 59, top hold-down finger 63, first top gear segment 55A,
second top gear segment 558, and top support rods 45. Through their
supportive association with upper section 10A of accumulating apparatus 10,
ali of these components pivot away from accumulation area 20 as one
assembly, thereby facilitating access into accumulation area 20 to enable
removal of sheets without damage thereto.
Although not specifically shown in the drawings, it will be understood that
an appropriately programmed electronic controller such as a microprocessor, or
other conventional means for executing instructions and receiving andlor
sending signals, is placed in communication with the variable speed motor
driving dynamic infeed rollers 53A and 53B, the motor driving transport belts
81A and 818, the actuator 131 driving front stop fingers 113, the motor 161
driving output rollers 141A and 1418, the motor driving exit rollers 181A and
1818, and the solenoids 207A and 2078 driving the side guides 191A and
191 B. The electronic controller can thus maintain synchronization of these
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various components of accumulating apparatus 10, as well as control the
respective operations of specific components. It will be further understood
that
the electronic controller can receive feedback from upstream and downstream
devices in order to determine the proper speeds of the various rollers, and
can
receive feedback from various sensors situated in accumulating apparatus 10
to determine the location of sheets or to count the number of sheets
accumulating in accumulation area 20. Thus, the electronic controller
determines the dynamic speed profile of dynamic infeed rollers 53A and 53B,
as described hereinabove, in order to feed sheets at an initial input speed
and
slow the sheets down to a reduced registration speed as the sheets approach
front stop fingers 113. In addition, the electronic controller determines the
proper time to side jog the sheet stack as sheets enter accumulation area 20.
Moreover, the electronic controller determines when the proper number of
sheets have accumulated, after which time the electronic controller causes
front stop fingers 113 to retract out of the material flow path, transport
belts 81A
and 81 B to move the stack forvvard into output rollers 141A and 141 B, output
rollers 141 A and 141 B to move the stack to exit rollers 181 A and 181 B, and
the
exit rollers 181A and 1818 to move the stack toward an area or device
downstream from accumulating apparatus 10. The provision of independent
input, transport, and output drives enables accumulating apparatus 10 to be
matched with any upstream and downstream devices.
In one specific but non-limiting embodiment, accumulating apparatus 10
supports sheets that are 5.50 inches (140 mm) to 12.00 inches (305 mm) wide
and 3.50 inches (89 mm) to 14.00 inches (356 mm) long. This accumulating
CA 02547302 2003-02-12
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apparatus 10 can accumulate 1 to 30 sheets of 18-Ib. to 24-Ib. paper.
Conversion time related to material size and over/under accumulation mode
switching is approximately two minutes or less. In addition, this accumulating
apparatus 10 can accommodate material skew from 0.5 degrees to 2 degrees,
depending on sheet length. Sheets are registered from lead-to-trail edge and
side-to-side within a 0.008-inches (0.20-mm) offset.
The operation of accumulating apparatus 10 as described hereinabove
will now be.summarized with reference being made primarily to Figures 4, 5
and 8. As an incoming sheet IS enters accumulating apparatus 10 under the
control of an upstream device, incoming sheet IS passes through top and
bottom entrance guides 51A and 51 B into the nip formed by top and bottom in-
feed rollers 53A and 53B. Incoming sheet IS thus enters accumulation area 20
under the control of dynamic in-feed rollers 53A and 538. At this point, the
rotational speed of dynamic in-feed rollers 53A and 53B is preferably matched
to the output speed of the upstream device. Preferably, this matched speed is
at or near the maximum speed of dynamic in-feed rollers 53A and 53B, and
thus corresponds to the maximum flow rate of incoming sheets IS into input
section 15 of accumulating apparatus 10. Dynamic in-feed rollers 53A and 53B
advance incoming sheet IS into accumulating apparatus 10 for a
predetermined distance, at the top speed that is preferably matched to the
output speed of the upstream material processing device. The speed of in-feed
rollers 53A and 53B is then dynamically reduced to dynamically slow down the
flow rate of incoming sheet IS, thereby allowing the lead edge of incoming
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sheet IS to contact spring-loaded front stop mechanism 110 without the risk of
damage.
The recoiling reaction of front stop mechanism 110 induces a jogging
action that registers incoming sheet IS with the rest of sheet stack S between
front stop mechanism 110 and either top accumulation ramp 59 or bottom
accumulation ramp 61 (depending on whether accumulating apparatus 10 is
set for under-accumulation or over-accumulation as described hereinabove).
Dynamic in-feed rollers 53A and 53B increase speed back up to top velocity to
advance subsequent incoming sheets IS into accumulation area 20, and the
slowdown process again occurs such that the dynamic speed profile is
implemented for each cycle of incoming sheets IS being fed into accumulating
apparatus 10. Each incoming sheet IS can be fed completely individually, in
subsets, or in overlapping relation~to other incoming sheets IS.
W hen a complete set of sheets (sheet stack S) has been over- or under-
accumulated, the following exit routine transpires. Spring loaded front stop
fingers 113 retract out of the sheet feed path. Side guides 191A and 1918
(see Figures 13-15) contact the sides of the sheet set and register the sheets
from side-to-side in the manner described hereabove. Side guides 191A and
191 B hold the sheet set in a registered position for a predetermined time of
the
exit routine and then release the sheet set. Dual-Tugged transport belts 81A
and 81 B start to cycle. In one example, one cycle equals 180 degrees at a
fixed speed .of approximately 30 ips. The low speed of dual-lugged transport
belts 81A and 81 B minimizes trail-edge damage when outside lugs contact 93
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(see Figure 6) and advance the set of accumulated sheets. As dual-lugged
transport belts 81A and 818 cycle, they contact the trail edge of the set of
accumulated sheets and advance the lead edge of the accumulated set into the
pair of output rollers 141 A and 1418. As described hereinabove, output
rollers
141A and 141 B are positioned at a fixed distance downstream from front stop
fingers 113, and their speed is preferably matched with that of the downstream
device, which ordinarily will be a fixed, constant speed ranging between,
e.g.,
approximately 80 ips to approximately 180 ips. As the lead edge of sheet stack
S enters output rollers 141 A and 141 B, output rollers 141A and 141 B advance
sheet stack S at a higher rate of speed-than dual-lugged transport belts 81A
and 81 B. As sheet stack S advances in this manner, its lead edge enters the
pair of fixed-position exit rollers 181A and 1818, the speed of which is
preferably matched with the speed of output rollers 141A and 141 B and that of
the downstream device. Once the trail edge of this sheet stack S has passed
by spring-loaded front stop fingers 113, front stop fingers 113 extend back
into
the sheet path ready for the next set of sheets to accumulate.
'It can be seen from the foregoing that no moving components of
accumulating apparatus 10 contact the sheet material during accumulation
thereof. Thus, the risk of toner smudging/transfer to the sheet material is
significantly reduced or even eliminated. Moreover; the adjustments to
accumulating apparatus 10 required to effect a change-over between under-
accumulation and over-accumulation, and to effect a change in material size,
is
quick, easy, and tool-less.
CA 02547302 2003-02-12
-42-
It will be understood that various details of the invention may be
changed without departing from the scope of the invention. Furthermore, the
foregoing description is for the purpose of illustration only, and not for the
purpose of limitation-the invention being defined by the claims.
