U.S. patent application number 11/033617 was filed with the patent office on 2006-07-13 for speed control for sheet handling apparatus.
This patent application is currently assigned to Pitney Bowes Limited. Invention is credited to Geoffrey A. Farmer, Keith G.R. Watts.
Application Number | 20060151941 11/033617 |
Document ID | / |
Family ID | 36652493 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060151941 |
Kind Code |
A1 |
Farmer; Geoffrey A. ; et
al. |
July 13, 2006 |
Speed control for sheet handling apparatus
Abstract
A sheet handling apparatus is disclosed having a first sheet
feeding means for advancing a sheet along a sheet path, a second
sheet feeding means for feeding the sheet along a continuation of
the sheet path, driving means for driving the first sheet feeding
means independently of the second sheet feeding means and for
common drive of the first and second sheet feeding means, and a
drive controller arranged to control said driving means to enable a
sheet to be driven along the sheet path from the first sheet
feeding means to the second sheet feeding means whilst the second
sheet feeding means remains undriven and to enable continued
feeding of the sheet by both sheet feeding means.
Inventors: |
Farmer; Geoffrey A.;
(Ingatestone, GB) ; Watts; Keith G.R.; (Abbots
Langley, GB) |
Correspondence
Address: |
PITNEY BOWES INC.;35 WATERVIEW DRIVE
P.O. BOX 3000
MSC 26-22
SHELTON
CT
06484-8000
US
|
Assignee: |
Pitney Bowes Limited
Harlow
GB
|
Family ID: |
36652493 |
Appl. No.: |
11/033617 |
Filed: |
January 12, 2005 |
Current U.S.
Class: |
271/264 |
Current CPC
Class: |
B65H 5/025 20130101;
B65H 5/064 20130101 |
Class at
Publication: |
271/264 |
International
Class: |
B65H 5/00 20060101
B65H005/00 |
Claims
1. A sheet handling apparatus comprising: a first sheet feeding
means for advancing a sheet along a sheet path; a second sheet
feeding means for feeding the sheet along a continuation of the
sheet path; for driving the first sheet feeding means independently
of the second sheet feeding means and for common drive of the first
and second sheet feeding means; and a drive controller arranged to
control said driving means to enable a sheet to be driven along the
sheet path from the first sheet feeding means to the second sheet
feeding means whilst the second sheet feeding means remains
undriven and to enable continued feeding of the sheet by both sheet
feeding means.
2. The sheet handling apparatus according to claim 1, wherein for
said common drive, the feeding speed of the first feeding means is
set at a specific ratio with respect to the feeding speed of the
second feeding means
3. The sheet handling apparatus according to claim 1, wherein for
said common drive the feeding speed of the first feeding means is
matched with the feeding speed of the second feeding means.
4. The sheet handling apparatus according to claim 1, wherein the
second sheet feeding means is stationary when undriven.
5. The sheet handling apparatus according to claim 2, wherein the
second sheet feeding means is stationary when undriven.
6. The sheet handling apparatus according to claim 1, wherein the
first sheet feeding means comprises a feed roller.
7. The sheet handling apparatus according to claim 6, wherein the
second sheet feeding means comprises one or both of a feed roller
and a traction belt.
8. The sheet handling device according to claim 1, wherein the
driving means comprises: a first motor coupled to the first feeding
means; a second motor coupled to the second feeding means; and a
coupling arrangement for selectively coupling the second motor to
the first feeding means.
9. The sheet handling apparatus according to claim 8, wherein the
coupling arrangement is a series of gears, having appropriate
ratios to set the relative feeding speeds of the first and second
feeding means.
10. The sheet handling apparatus according to claim 9, wherein the
coupling arrangement comprises: a feeding gear connected to moving
parts of the first feeding means; a receiving gear connected to
moving parts of the second driving means; and a belt or chain
passing around both gears and constraining the feeding gear to
rotate in synchronism with the receiving gear.
11. The sheet handling device according to claim 8 wherein the
coupling arrangement comprises a selectively operable clutch.
12. The sheet handling device according to claim 9 wherein the
coupling arrangement comprises a selectively operable clutch.
13. The sheet handling device according to claim 8 wherein the
coupling arrangement comprises a selectively operable clutch.
14. The sheet handling device according to claim 13 wherein said
clutch is a one-way clutch.
15. The sheet handling device according to claim 1, wherein the
second sheet feeding means forms part of an accumulation apparatus
for accumulating a plurality of sheets fed to the accumulation
apparatus by the first sheet feeding means.
16. A method of feeding sheets in which a sheet is fed by first
feeding means to a second feeding means whilst the second driving
means remains undriven and the sheet is further advanced by both
the first and second feeding means set at a specific ratio
therebetween.
17. A method according to claim 16, in which the first and second
feeding means are driven by respective drive shafts which are
coupled together by means of a selectively operable coupling
arrangement.
18. A method according to claim 16, in which the speeds of the
first and second feeding means are matched.
19. A method according to claim 17 in which the speeds of the first
and second feeding means are matched.
Description
FIELD OF THE INVENTION
[0001] This invention relates to sheet handling apparatus and is
applicable to an apparatus and method for processing of elongate
elements or articles, and in particular to an apparatus and method
for selectively performing a plurality of operations on each of a
number of different sheet or booklet elements, as well as
envelopes.
BACKGROUND OF THE INVENTION
[0002] It is well known to provide a machine for successively
performing several operations on various sheet elements. For
example, operations on an envelope might include flapping,
inserting, moistening and sealing, whilst operations on one or more
sheets might include collating, folding and inserting into an
envelope. It is further known to provide a machine which collates
several sheets of paper into a bundle, folds the bundle, places an
insert, such as a leaflet or booklet into the bundle, provides an
envelope which is held open, inserts the folded sheets into the
envelope, moistens the envelope and seals it, before ejecting the
envelope into a receiving tray or bin. Each of these operations is
distinct and requires a separate and unique processing region
within the machine in order to successfully and repeatably carry
out the required operation on the respective element. As a result,
folder/inserter machines of the type described hereinbefore are
typically large and complicated to program.
[0003] Recently, there have been moves towards reducing the size of
such folder inserter machines in order to make them more accessible
to smaller businesses, such as SOHO (small office/home office)
operations. In order to be successful in this environment, the
folder/inserter must occupy a small footprint (i.e. the area of
floor/desk-surface occupied), perform reliably, and be easy to
control without requiring specialist training.
[0004] GB-A-2380157 discloses a small office folder/inserter having
two trays, and for storing sheets to be folded and the other for
storing inserts to be inserted into the sheets. One location is
specified for folding said sheets, another location for placing the
insert into the folded sheets, and a further location for inserting
the folded bundle into an envelope. The machine further comprises a
location for storing envelopes, means for opening said envelopes
and holding the envelopes open to receive the folded bundle at the
inserting location, a section for moistening the flap of the
envelope and a section for closing the flap of the envelope to seal
it and ejecting the envelope to a receiving tray. Because of the
small size and compactness of the machine, it is suitable for
performing only a limited number of cycles in a given time period,
i.e. it does not have a very high-volume throughput. Further, such
machines can lack versatility, since they are suitable only for
performing the respective feeding, folding, inserting, envelope
opening, envelope moistening and sealing operations on a limited
range of sizes of sheets/inserts.
[0005] Large organisations, such as banks, telephone companies,
supermarket chains and the government, for example, are often
required to produce extremely large throughputs of
specifically-addressed mail to a regional or national audience.
Machines capable of producing the high volumes required, whilst
simultaneously accurately ensuring that the correct content is sent
to the individual recipients, are typically very large, often
occupying an entire warehouse. By contrast, existing small office
equipment is typically capable of producing mailshots for a few
hundred to one or two thousand addressees.
[0006] Demand, therefore, exists for a machine of intermediate
production capacity, typically for small to regional businesses,
which does not occupy a vast quantity of the available office
space. Particularly in large cities, office space is charged at
premium rates for each square metre. As such, the cost of running
and maintaining a folder/inserter will also comprise the cost of
renting the office space which it occupies.
SUMMARY OF THE INVENTION
[0007] For folder/inserter apparatuses intended for small and
medium sized businesses, it is at least desirable, if not
necessary, for the machine to be able to accommodate a range of
different materials. For example, it will be necessary to
accommodate different thicknesses of sheet element, as well as
different sizes and numbers thereof. Similarly, any materials to be
inserted within a folded package might range from a compliments
slip to an entire booklet, including inserts of unconventional size
or shape. It is also advantageous for such machines to be able to
accommodate different sizes of envelopes, such as A4 and A5,
depending on the material to be inserted thereinto.
[0008] When accumulating a document in a mail creation machine it
is desirable for the delivery rollers and the receiving
rollers/belt to be very closely matched in speed. This prevents the
paper being stretched if the feed rolls are too slow or crumpled if
too fast. Driving with two independent motors requires very
accurate control systems, so the usual method of matching the speed
is to mechanically link the two and have one motor for both. This
however makes it difficult to stop one sheet in the accumulator and
wait for the next to arrive. This invention links the two drives
via an overrun clutch allowing the delivery motor to feed
independently of the receiving motor whilst maintaining accurate
speed matching when the receiving motor is on.
[0009] According to one aspect of the present invention, there is
provided a sheet handling apparatus comprising: a first sheet
feeding means for advancing a sheet along a sheet path; a second
sheet feeding means for feeding the sheet along a continuation of
the sheet path; means for driving the first sheet feeding means
independently of the second sheet feeding means and for common
drive of the first and second sheet feeding means; and a drive
controller arranged to control said driving means to enable a sheet
to be driven along the sheet path from the first sheet feeding
means to the second sheet feeding means whilst the second sheet
feeding means remains undriven and to enable continued feeding of
the sheet by both sheet feeding means.
[0010] According to a second aspect of the invention, there is
provided a method of feeding sheets in which a sheet is fed by
first feeding means to a second feeding means whilst the second
driving means remains undriven and the sheet is further advanced by
both the first and second feeding means set at a specific ratio
therebetween.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a better understanding of the invention and to show how
the same may be carried into effect, reference will now be made, by
way of example, to the accompanying drawings, in which:
[0012] FIG. 1 is a cross-sectional view of a sheet handling
apparatus detailing the different machine sections;
[0013] FIG. 2 is a cross-sectional view of a sheet feeder deskew
mechanism;
[0014] FIG. 3 is a cross-sectional view showing the sheet feeder
collation section;
[0015] FIG. 4 is a schematic view of an accumulator according to an
embodiment of the present invention;
[0016] FIG. 5 is a cross-sectional view showing the accumulator
installed in a sheet handling apparatus;
[0017] FIG. 6 is a cross-sectional view showing the sheet folding
section; and
[0018] FIG. 7 shows a speed compensation mechanism according to one
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Throughout the drawings, like numerals are used to identify
like components.
[0020] FIG. 1 shows a folder/inserter apparatus 1000 embodying the
present invention. This embodiment is exemplary only, and is used
to highlight and explain the inventive concept defined by the
appended claim.
[0021] FIG. 1 shows a cross-sectional view of the folder/inserter
apparatus 1000 and schematically shows various sections of the
machine. The folder/inserter apparatus 1000 comprises a sheet
feeder section including sheet feeders 1, 2, 3 and 4, from which
sheets are fed into a collation section 100 where they are collated
into an ordered paper stream. The paper stream is then fed along a
sheet feed path which merges with an inlet from a convenience
feeder 200, which acts as an alternative sheet feeder for certain
documents. The sheets then pass through an accumulator section 300
where they are grouped together as an ordered and aligned package.
From the accumulator, the sheets pass through a sheet folder 500.
Inserts fed from insert feeders 401 and 402 are collated in an
insert feeder collation section 450 and then fed into a folded
collation. An envelope is fed from an envelope feeder 600 along an
envelope transport path 650 to a flapper 700 where the envelope
flap is opened and the mouth of the envelope held open at insertion
section 750 to receive the folded collation. The collation is
inserted into the envelope and the envelope is fed into a final
section 800 where the gum on the envelope flap is moistened and the
envelope sealed. The sealed envelope is then ejected into a
receiving tray or bin.
[0022] Referring now to FIG. 1 in more detail, there is shown an
inlet section which includes four sheet feeders 1, 2, 3 and 4. Each
of these sheet feeders comprises a respective sheet feeder tray
5,6,7 or 8 into which a stack of sheets may be placed. The sheets
in each tray are fed individually into a sheet feed path by
respective sheet deskew mechanisms 50 which each act to separate a
single sheet from the top of a stack of sheets in the associated
sheet feeder tray and to feed the separated sheet into and along
the sheet feed path. Four deskew mechanisms 50 are shown in FIG. 1,
only one of which is identified by reference numeral 50 in FIG. 1.
The other three deskew mechanisms are either identical or
equivalent to that labelled 50. Each of the sheet feeder deskew
mechanisms feeds into a common sheet feed path via respective sheet
feeding inlet paths P1, P2, P3 and P4. The convenience feeder 200
similarly feeds into the common sheet feed path. All inlets to the
sheet feed path from the four sheet feeders and from the
convenience feeder 200 merge by a point T within the sheet feeder
collation section 100. From the point T, the sheet feed path
continues as a single sheet feed path up to the folder station 500.
The sheet feed path passes first through the accumulator 300, where
a plurality of sheets may be brought together to form an aligned
and ordered package. The sheet feed path then passes through the
sheet folding section 500 which produces a desired fold pattern in
the accumulated document. As shown on the righthand side of FIG. 1,
a pair of insert feeders 401, 402 are provided. Each insert feeder
401, 402 has a respective feeder tray 411, 412 which holds a
plurality of inserts to be inserted into the folded collation. Each
insert feeder further has an associated feeder device 400 for
feeding a single insert into the insert collation section 450.
Inserts fed into the insert collation section 450 are collated
together and then inserted into the main folded collation. On the
lefthand side of FIG. 1 below the sheet feeders 1,2,3 and 4 is
located the envelope feeder 600. Envelope feeder 600 holds a
plurality of envelopes which are fed along the envelope transport
path 650 and into the flapper mechanism 700. The flapper mechanism
700 opens the flap of each envelope and uses mechanical fingers to
hold the mouth of the envelope apart at insertion section 750 in
order to allow the folded sheets (and any inserts) to be projected
into the envelope. The envelope, with inserted documents, then
continues along the sheet feed path to the final section 800 in
which the gum on the envelope flap is moistened and the flap is
sealed. The sealed envelope is then ejected from the
folder/inserter apparatus 1000.
[0023] The operation of the folder/inserter apparatus is now
considered in more detail with reference to FIGS. 2 to 6.
[0024] Referring now to FIG. 2, the sheet feeder deskew mechanism
50 comprises a separator roller 51 which applies a driving force to
the uppermost sheet in a stack in the sheet feeder tray. The
separator roller 51 presses against a separator pad 52, normally in
the form of a separator stone. This separator stone 52 prevents
more than one sheet at a time from being fed into the sheet feed
path by the roller 51. The single sheet removed from the sheet
feeder tray by the separator roller 51 is then driven towards a
deskew roller pair 53 which is maintained stationary. As the sheet
engages the nip defined by the deskew roller pair 53 it is caused
to buckle (as illustrated at Z). This forces the lead edge of the
sheet to align with the nip of the deskew roller pair 53. The
separator roller 51 is then stopped and the deskew roller pair 53
operated to drive the sheet along the sheet feed path and into the
sheet feeder collation section 100.
[0025] With reference to FIG. 3, each sheet fed from a sheet feeder
1,2,3 or 4 or convenience feeder is received in the respective
sheet feeding inlet path P1,P2, P3, P4 or P5 defined by guides G1
and G4 to G10. The sheet feeding inlet paths merge into a single
sheet feed path in the sheet feeder collation section 100. Sheet
feeding roller pairs 101, 102, 103 and 104 are located along the
sheet feed path for forcing the sheets along the sheet feed
path.
[0026] In a typical sheet folding/inserting operation involving a
four-page document, referring also to FIG. 1, the first sheet
feeder tray 5 receives a stack of sheets corresponding to page 1 of
the document, the second sheet feeder tray 6 receives a stack of
sheets corresponding to page 2 of the document, the third sheet
feeder tray 7 receives a stack of sheets corresponding to the page
3 of the document, whilst the fourth sheet feeder tray 8 receives a
stack of sheets corresponding to page 4 of the document. A single
sheet is then fed sequentially from each of the first to fourth
sheet feeders. The first sheet from the first sheet feeder 1 passes
into and along the sheet feeding inlet path P1 and partially along
the common sheet feed path. A sheet is then fed from the second
sheet feeder 2 such that the leading edge of the second sheet
partially overlaps the trailing edge of the first fed sheet within
the sheet feeder collation section 100. Similarly, the third sheet
is fed so that the leading edge of the third sheet partially
overlaps the trailing edge of the second sheet, whilst the fourth
sheet is fed so that its leading edge partially overlaps the
trailing edge of the third sheet. This forms a collation of the
sheets along the sheet feed path in the sheet feeder collation
section 100. The guides G1 to G10 defining the sheet feed path are
configured and arranged to ensure that, as the sheets are
sequentially fed into the sheet feed path and carried to overlap as
described above, they become correctly collated in the intended
order.
[0027] Because the requirement is that the adjacent sheets in the
sheet collation only partially overlap at the leading and trailing
edges, it is possible to drive the sheet collation along the sheet
feed path at high speed without requiring a complex control system
to ensure that each of the sheets is correctly aligned with those
adjacent to it. This enables a high-volume throughput of mail
packages to be achieved.
[0028] Referring now to FIGS. 4 and 5, the sheet collation is then
driven from the collation section 100 into an accumulation section
300 comprising a vertical accumulator 350. Here, as each sheet
arrives in the accumulator 350, it is gripped and forcibly advanced
through the accumulator by a pair of traction belts 351 running
vertically and mutually parallel on a sled 352. A plurality of
spring-biased idler rollers 365 to 369 are provided for each
traction belt 351 to apply forces F1 to F5 to maintain the most
recently-arrived sheet in contact with the tractions belts 351.
Each sheet fed into the accumulator 350 arrives at an accumulation
chamber 364 defined on one side by a sled guide assembly SG
including the sled 352 and the traction belts 351 and on the other
side by a fixed guide assembly OG including fixed guide 353 and
idler rollers 365 to 367. The accumulation chamber 364 is
substantially straight and vertical, such that the collation is
accumulated into a vertical stack of sheets. At the bottom of the
accumulation chamber 364 is an accumulation gate 354 functioning as
a stopping device. Each sheet entering the accumulator 350 is
driven downwardly through the accumulation chamber 364 towards the
accumulation gate 354 by the traction belts 351 until its leading
edge comes into contact with the accumulation gate 354. This causes
the sheet leading edge to impinge on the accumulation gate 354 and
the sheet to become correctly aligned within the accumulation
chamber 364. The sheet is then maintained within the accumulation
chamber 364 and rests on the accumulation gate 354, whilst further
driving of the traction belts causes slippage between the traction
belts 351 and the sheet. Thus, once the first sheet has been
stopped by the accumulation gate 354, the second and subsequent
sheets are consecutively driven into alignment with the first sheet
by the traction belts 351 driving each sheet in turn along the
accumulation path and against the accumulation gate 354 to form an
ordered collation. When all of the sheets in the collation have
been successfully grouped at the accumulation gate 354, the
accumulation gate opens to allow the collation to progress out from
the accumulation chamber 364 along the continuation of the sheet
feed path.
[0029] Referring now to FIG. 5, it can be seen that the accumulator
comprises the fixed guide assembly OG, and movable sled guide
assembly SG. The movable guide assembly SG includes driving means
in the form of the pair of traction belts 351. The fixed guide
assembly OG includes idler rollers 365 to 367 for pressing the
sheets to be accumulated against the traction belt 351 and rollers
361 to 363 for pressing the traction belt against the sheets to be
accumulated. The movable guide assembly also includes the sled 352
for assisting guidance of the sheets, or collations of sheets, into
an accumulated bundle whilst accommodating a variable thickness of
accumulation. These features define a section of sheet feed path
which is substantially vertical and acts as the accumulation
chamber 364. In the embodiment shown, the means for driving the
sheets downwardly towards the accumulation gate 354 is the pair of
traction belts 351, although any suitable system of belts and
rollers could be used. The present embodiment has two drive belt
assemblies which each consist of one of the traction belts 351, a
drive roller 355 and a secondary tension roller 356 which holds the
traction belt 351 under tension, along with idler rollers 361, 362,
363 in the sled 352 acting in opposition to the idler rollers 365
to 367 in the fixed guide assembly. The idler rollers 365 to 367
associated with the fixed guide 353 could alternatively take the
form of miniature drive belts biased towards the fixed idler
rollers 361,362,363 in the sled, but preferably sprung idler
rollers are biased towards the traction belts. Further, idler
rollers 368 and 369 are mounted on a further guide component
positioned above guide 353 (see FIG. 5). The idler rollers 365 to
369 may be arranged to apply a force to the sheet which varies
along the length of the accumulation chamber 364 and around the
drive rollers 355 of the traction belt mechanisms 351. Such a
variable traction force over the length of the accumulation
chamber, preferably ensuring a larger force towards the bottom of
the accumulation chamber, reduces the column strength of a sheet
required to enable it to resist the frictional driving forces of
the traction belts. In the present embodiment, the varied force is
achieved by using sprung idler rollers 365, 366 and 367, each of
which is biased towards the traction belts 351 by a different
spring force, the spring force being largest for roller 367 and
least for roller 365. The downward driving force is resisted at the
bottom of the accumulator by the accumulation gate 354, but it is
important that the traction forces from the driving means do not
cause the individual sheets to buckle or concertina.
[0030] In traditional accumulators, the accumulated collation must
be mechanically forced in order to propel it further along the
sheet feed path. Because contact can be achieved only with the
front and rear sheets at any time, the acceleration given to the
accumulated collation must be limited in order to ensure that
adjacent sheets do not slide relative to one another, thereby
spreading apart the accumulated collation. As a result of the
vertical orientation of the accumulation path in the present
embodiment, a downward acceleration of 1 g (i.e. under
gravitational force) can be achieved without mechanical forcing. In
addition, using additional forcing methods, a further acceleration
of 1 g may be imparted to the collation without resulting in the
separation of adjacent sheets. Hence, accumulated collations
emerging from the accumulator 350 of the present embodiment may be
accelerated at roughly 2 g without resulting in sliding separation
of the sheets. This allows for faster progression of the
accumulated collation through the folder/inserter 1000, resulting
in a higher-volume throughput of sheet packages.
[0031] Referring again to FIGS. 4 and 5, the operation of the
accumulation section will be described in more detail.
[0032] As already outlined, as the sheet collation enters the
accumulation section, the individual sheets are engaged by the pair
of accumulator driving belts 351. At the accumulator inlet side, a
pair of drive rollers 104 (FIG. 5) feeds the sheet material along
the sheet feed path towards the drive belts 351. The drive belts
351 are stopped whilst the drive rollers 390 continue to feed a
sheet into the accumulator 350. This allows subsequent sheets
arriving after the first to be effectively overlapped with the
sheet or sheets already in the accumulator 350 to ensure that they
are engaged by driving means 351 and accumulated in the correct
order.
[0033] According to the present embodiment, there are three methods
by which a document may be fed into and accumulated in the
accumulator. The first is as described above, where individual
sheets are fed from the separate feed trays 1, 2, 3, 4 (FIG. 1),
loosely collated in the sheet feeder collation section 100, and
then accumulated in the accumulator 350. In this mode, the sheets
pass directly into the accumulation chamber in the correct order
because they are already partially overlapped. As such, the second
and subsequent sheets are always received between the sheet(s)
already present in the accumulator and the traction belts 351, so
that they are driven downwardly and accumulated against the
accumulation gate 354 in the correct order.
[0034] The folder/inserter may also operate in two further modes
for folding a mail piece and inserting it into an envelope.
According to the second method, pre-stapled sheets, for example a
five-page document stapled in one corner, are placed in the
convenience tray 200. This document is then fed directly to the
accumulation chamber, where no further accumulation is required
owing to the sheets being stapled. The document then exits the
accumulation chamber and is folded and inserted as normal.
[0035] According to the third method of operation, a plurality of
ordered, loose sheets are placed in convenience feeder 200 or one
of the sheet feeder trays 5, 6, 7 or 8 (FIG. 1). These sheets are
fed successively one-at-a-time along the sheet feed path and into
the accumulator. However, in this mode, the sheets are not
partially overlapped in the paper feed path, and this leads to the
risk that the sheets will become incorrectly ordered, or
incorrectly fed into the accumulator, leading to mis-collated mail
packages or a jam in the folder/inserter machine 1000.
[0036] To overcome this problem, a trail edge deflector 380 is
provided (FIGS. 1, 5). In the third mode, the trail edge deflector
acts to lift the trail end of a sheet whose lead end is already in
the accumulator 350, to thereby ensure that the subsequent sheet to
arrive is fed into the accumulator between the previous sheet and
the traction belts 351. The trail edge deflector 380 comprises a
roller 381 through which there is a passage 382 suitable for
allowing one or a plurality of sheets to pass through the roller.
The passage is flared at the inlet and outlet thereof to better
accept the introduction of a sheet leading edge, to prevent jamming
of the folder/inserter 1000.
[0037] In the first and second modes the sheet(s) or stapled
document(s), etc. simply pass through the passage in the deflector
and into the accumulator.
[0038] In the third mode of operation, the sheets arriving
individually pass part-way through the passage, and the leading
edge of the sheet enters the accumulator 350 and is contacted by
the traction belts 351 to drive it down against the accumulation
gate 354. As the trail edge of each sheet reaches the trail edge
deflector, the deflector rotates by 180.degree. (anticlockwise as
shown in FIG. 5). This forces the trail edge of that sheet upwards
and it then lies above the trail edge deflector. The inlet and
outlet of the passage 382 through the trail edge deflector have
then reversed positions and the subsequent sheet enters the passage
through what was previously the outlet. This is possible because
the passage has a cross-section with rotational symmetry. The
subsequent sheet is then guaranteed to be fed into the accumulator
underneath the trail edge that was previously deflected, i.e.
between the previous sheet and the traction belts.
[0039] This third mode of operation is particularly useful when,
for example, a document has been printed by a laser jet printer and
is collated in the correct order, and it is not desired to have to
sort the individual pages of the document into the appropriate
individual sheet feed trays.
[0040] After leaving the accumulator, the collation passes into the
folding section 500 which contains a variable folding apparatus.
The operation of such a folding apparatus is known, for example
from GB-A-2380157. Brief explanation is given here for a more
complete understanding.
[0041] Referring to FIG. 6, the folding apparatus comprises four
rollers 501,502,503 and 504 arranged to form three pairs 510,520
and 530. The leading edge of the collation passes through the first
roller pair 510 and into a buckle chute 511 until it reaches an
adjustable stop 512, here constituted as a pinch roller pair 513
which selectively stops the collation based on detection of the
leading edge position. At this point, the first roller pair
continues to feed the sheet collation, causing it to buckle, and
causing the buckled portion to enter the nip between the second
roller pair 520. This results in the buckled portion being fed
through the second roller pair 520 and forming a fold at the
buckle, at a predetermined position. The folded edge then becomes
the lead edge of the collation and it is fed through the second
roller pair 520 into a second buckle chute 521 until it moves into
contact with a second stop 522 (which is preferably a pinch roller
pair 523) which halts its movement. The second roller pair 520
continues to feed the trailing edge of the sheet collation
therethrough. Again, this causes the collation to buckle, and the
second buckle is forced into the nip of the third roller pair 530,
resulting in a second fold in the sheet collation at a
predetermined point in the region of the second buckle.
[0042] By selectively determining the point at which the sheet
collation is halted by the stops 512,522 at each stage, it is
possible to always achieve the folds in the desired position.
Further, by appropriately selecting the distance from the roller
pairs at which the collation is halted, the same apparatus can
selectively perform either a double fold, a "Z" fold or a "C" fold
in the sheet collation. Equally, the sheet collation need only be
folded a single time, for example simply folded in half. This
single fold is achieved by operation of a half-fold mechanism 550.
If a half-fold operation is selected, the half-fold mechanism 550
moves in the direction of arrow A to an interference position where
it intercepts and redirects the accumulated collation as it exits
the first roller pair 510. The collation is then directed
immediately through the second roller pair 520, rather than into
the first buckle chute 511. Accordingly, the first fold is never
made in the collation at the nip of the second roller pair, and
only a single fold is created as the collation is buckled in the
second buckle chute 521 and the buckle passes through the third
roller pair 530, as normal.
[0043] Referring again to FIG. 1, after the final fold is made, one
or more inserts may be fed from insert feeders 401 and 402 shown on
the right hand side of FIG. 1. The present embodiment has two
insert feeders 401 and 402, which both feed an insert into and
along an insert feed path. One or both inserts are then collated in
the insert feeder collation section 450 and the collated inserts
are held at insert staging area I whilst the sheets are folded.
These collated inserts are then fed into the final fold in the
sheet collation and form part of the folded document. Typically,
these inserts might be booklets, business reply envelopes,
compliment slips, product samples, etc. of varied shape, size,
thickness and pliability.
[0044] Below the sheet feeders 1 to 4 is located the envelope
feeder 600. This holds a plurality of envelopes in a stack, and has
an associated mechanism for removing the single uppermost envelope
from the stack and feeding said envelope along the envelope
transport path 650. The envelope first undergoes a flapping process
in flapper section 700, in which the flap is opened. The envelope
is then held in the insertion region 750, where it is stopped.
Mechanical fingers engage with and hold open the mouth of the
envelope. In this state, the folded mail collation (including
inserts) is inserted into the envelope by projecting the mail
package towards the open mouth with sufficient velocity that its
momentum will force it inside the envelope. This mail piece,
comprising the folded mail package within the envelope, then
proceeds to the sealing and ejection section 800. In the sealing
and ejection section there is a moistening device 820 where the gum
seal on the envelope flap is moistened. The envelope is then passed
through a sealing/ejection mechanism 840. This performs a process
which shuts and seals the moistened flap and ejects the envelope
from the folder/inserter apparatus 1000 into a receiving tray or
bin.
[0045] According to the above description, as the sheet collation
enters the accumulation section, the individual sheets are engaged
by the accumulator driving means 351. In the present embodiment,
this accumulator driving means takes the form of a pair of traction
belts. In the paper feed path there are sheet feed path driving
means 104 feeding the sheet material along the sheet feed path
towards the accumulator driving means 351. Regardless of the form
of the sheet material--whether it be a partially overlapped
collation (as described above), a plurality of single sheets in
succession or a stapled pamphlet--it is necessary to accurately
match the "feeding speed" of the sheet feed path driving means 104
with the "receiving speed" of the accumulator driving means 351.
Referring to FIG. 7, there is shown a speed-matching mechanism 900
for accurately matching the feed rates of the sheet feed path
driving means 104 and the accumulator driving belts 351, shown
schematically in FIG. 7, under control of a system controller 907.
Simple speed-matching can be achieved by mechanical
interaction--i.e. via a system of gears or a chain and sprocket
connection linking the two driving means and forcing them to
produce a matched feed rate. However, in order for the accumulator
350 to function properly, it is necessary to be able to stop the
accumulator driving means 351 whilst continuing to drive sheet
material into the accumulator with the sheet feed path driving
means 104. This is necessary to enable the accumulator driving
means 351 to be halted by the drive controller 907 whilst a
subsequent sheet is fed into the accumulator in the correct order,
thereby creating or increasing an overlap between adjacent
sheets.
[0046] The mechanism 900 of the present embodiment concerns two
coupled rotational driving systems--one comprising traction belts
351 of the accumulator and the other comprising the drive rollers
104 on the sheet feed path. Each driving system comprises a
respective motor, i.e. a feeding motor 901 connected via a
rotational shaft 902 to the drive rollers 104 and a receiving motor
903 connected via a second rotational shaft 904 to the drive roller
of the accumulator driving means 351. Both motors are controlled by
a system controller 907. The rotational shafts of the two motors
901,903 are linked by a drive belt 905 which rotates with the
rotational shaft 902 of the feeding motor 901. The drive belt 905
is coupled to the rotational shaft 904 of the receiving motor 903
via an overrun clutch 906. This allows the feeding motor 901 to
turn whilst the receiving motor 903 remains stationary. However,
when it is desired to feed a sheet by means of the drive belt 351
of the accumulator, the receiving motor 903 begins to rotate. The
motors may be controlled such that the receiving motor 903 will be
driven at higher power than the feeding motor 901, thereby ensuring
that the feeding motor 901 does not "overtake" the receiving motor
903. The feeding motor 901 may be unpowered in this phase, but it
is preferred that it should be powered in order to distribute the
load required to drive the sheet material between the two motors.
Using the arrangement described, it is possible to hold the
accumulator receiving motor 903 stationary whilst the feeding
roller 104 drives a sheet into overlapping arrangement with another
sheet held static in the accumulator 350. When the accumulator
driving motor 903 is activated, and both motors are running
simultaneously, the sheets will not stretch or become buckled since
the sheet will be fed at precisely the same feed rate by both the
sheet feed roller 104 and the accumulator drive belts 351.
[0047] Thus, two independent drive systems are provided, each
consisting of: a motor driving a roller set, via a combination of
shafts, pulleys, belts and/or gears. Both motors have speed control
systems and can be driven independently via a machine controller
907. The two drives are then linked via belts and pulleys and/or
gears, with one of them linked to an overrun clutch. This clutch is
set up such that when only motor 903 is driven in the direction of
paper travel, both the feeding and receiving rollers will turn.
However, if only motor 901 is driven in the direction of paper
travel, only the feeding roller will turn. The method of operation
is then: motor 901 is powered and turns the "feed rollers"; this
drives a sheet of paper towards the "receiving rollers". As the
paper approaches, motor 903 is powered and controlled to drive at
the chosen speed. Motor 901 power may be reduced to ensure that,
although it assists in the driving, it does not overtake motor 903,
or power may be removed from motor 901. The "feed rollers" turn
until the sheet has passed, and the motors are then stopped. With
the arrival of the next sheet, motor 901 starts again, turning just
the "feed rollers" to advance a second sheet of paper. This sheet
is transported towards the "receiving rollers" and the awaiting
first sheet which remains stationary, thus enabling the two sheets
to be overlapped.
[0048] Thus, semi-independent drive of two separate drive systems
can be provided such that the feeding roller can be driven forward
without affecting the receiving roller. The use of a mechanical
link incorporating an overrun clutch means that if the receiving
roller is driven, the feed roller will also be driven at a speed
defined by the gear/pulley ratios. Optionally, motor 901 can still
be driven at this time, in order to take some of the load, as long
as the power is not sufficient for it to overtake motor 903.
[0049] The exact drive train from each motor to its respective
roller is unimportant, and the motors may be linked to the roller
drive shaft by a series of gears, belts and pulleys, if desired.
The overrun clutch can, instead, be put on the motor 901 drive
shaft, but it must be mounted in reverse so that it performs the
same function.
[0050] The clutched link introduces very few additional components,
all of a low cost. The use of this clutch ensures that the speed is
very accurately matched through the gear ratios without resorting
to complex control systems with precision feedback. There is also
no use of expensive electromechanical clutches with the associated
risk of wear and failure that these can entail.
[0051] Importantly, although the feeding speeds of the feeding
rollers and receiving rollers may be matched exactly, it is often
desirable to have the two roller sets linked so as to be driven
having a predetermined specific ratio between their feeding speeds.
It may, for example, be desirable to set the feeding speed of the
feeding rollers slightly higher than the feeding speed of the
receiving rollers in order to ensure that a buckle is normally
formed in the sheet, in order to account for tolerances in roller
diameter/feeding speed due to wear, manufacturing defects, etc.
[0052] Moreover, although it is necessary that the feed rollers 104
should be drivable independently of the receiving roller and belts
351, it is not absolutely necessary to employ two separate drive
motors if suitable selectable drive chains and/or clutches are
coupled to a single motor.
* * * * *