Patent Application
20060151932
This invention relates to a guiding apparatus for use in an accumulator of a 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.
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.
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.
GB-A-2380157 discloses a small office folder/inserter having two trays, one 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.
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 correct 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.
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.
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 compliment 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.
One operation often carried out in such folder/inserter apparatuses is the accumulation of a plurality of individual sheets into an ordered bundle. This can typically be achieved by driving each sheet against a hard stop or other halting means, such as pinch rollers. When driving, for example, a piece of paper up to and against a hard stop or gate, in a system for accumulating several sheets of paper, the maximum drive force that can be applied is limited by the column strength of the paper before it buckles and becomes damaged. This can have an adverse effect on operation and may cause increased costs to achieve very tight tolerances on the drive force. Compressing the paper against a flat plate can increase the column strength by preventing the buckle from forming. However, a high normal force introduces a high resultant force from the friction, particularly between multiple sheets, which can then negate the increased drive force. Using a lower normal force on the plate reduces this extra friction (although doesn't remove it) but can enable the paper to push the plate away. Additionally it is often necessary to cope with a wide range of paper thicknesses and sometimes to allow exceptional document packs to pass through, such as those with staples. These can become trapped under the plate.
According to one aspect of the present invention, there is provided an accumulator apparatus for paper collations comprising: an accumulation chamber for receiving sheet material, the chamber defined by a fixed guide on one side, a movable guide on the other side and a movable stop member at one end; driving means for driving said sheet material against said stop member; and means for moving the movable guide between a first position in which it is spaced from the fixed guide by a gap sufficiently small to prevent buckling of the sheet material as it is driven by the driving means against the stop member, and a second position in which the movable guide is spaced away from the fixed guide for discharge of the sheet material from the chamber.
According to a second aspect of the invention, there is provided a guiding method comprising: driving sheet material into an accumulation chamber against a movable stop along a sheet feed path in a sheet feed direction between a fixed guide defining one side of said chamber and a movable guide defining the other side of said chamber; and selectively moving the movable guide between a first position in which it is in close proximity to the fixed guide, to prevent buckling of sheet material as it is driven against the stop and a second position in which the movable guide is spaced from the fixed guide for discharge of the sheet material from the chamber.
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:
Throughout the drawings, like numerals are used to identify like components.
Referring now to
The operation of the folder/inserter apparatus is now considered in more detail with reference to FIGS. 2 to 6.
Referring now to
With reference to
In a typical sheet folding/inserting operation involving a four-page document, referring also to
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.
Referring now to
Referring now to
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.
Referring again to
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 (
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 (
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.
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 (
To overcome this problem, a trail edge deflector 380 is provided (
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.
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° (anticlockwise as shown in
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.
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.
Referring to
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.
Referring again to
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.
As noted above, the sled guide assembly SG, which includes sled 352 and traction belts 351 provides a guide on one side of the accumulation path. The traction belts are arranged to engage with the arriving sheets along at least a portion of the width W and the length L (
By appropriately selecting the size of this gap, and using a large biasing force, it can be assured that the sled guide assembly SG will resist a large buckling force to prevent the accumulated sheets from buckling, but that the traction belts 351 will remain in contact with sheets in the accumulator with an appropriately minimal normal force regardless of the thickness of the sheet accumulation. This is important to ensure that the driving force does not become excessive, thereby buckling or damaging the sheets.
The sled 352 may also be stepped, as shown at 371 and 372 in
The sled 352 is movable from a first accumulation position (
The accumulation chamber has a 30 mm long narrowed exit and an inlet section of 80 mm length. The chamber thickness “t” is set by fixed guiding means 353 with bump stops 359 which set the precise distance between the two surfaces. The sled 352 is mounted onto a frame, which supports its vertical position when the gate 354 is open, and mounts a set of springs which push the sled 352 towards the fixed guiding means 353. The frame interlocks with a set of hooks to pull the sled open when required. This actuating frame is, in turn, linked to the gate 354 and is biased towards the sled 352 by compression springs.
Consequently, when at rest, the gate 354 is closed and the sled 352 is pushed towards the fixed guiding means 353 with a force of several Newtons. Additionally the series of springs, slots and buffers/stops linking and biasing the sled guide assembly SG and gate 354 ensures that a wide tolerance range can be accommodated in the component parts without adversely affecting the critical parameters of the paper path gap.
The sequence of operation for releasing an accumulated collation involves opening the gate, which pulls the frame back, the sled remaining pushed towards the fixed paper path by springs (not shown) on the internal frame of the feeder/inserter. Once the gate has opened far enough to be swept clean by the stationary sled, the sled hooks pick up on the moving actuation frame and pull the sled clear of the fixed paper path, leaving a minimum gap of 3.5 mm.
In the present embodiment, the driving rollers 355 of the traction belts 351 form part of the sled construction and define a curved path around the top of the sled 352 and into the accumulation chamber 364. Along the length of each traction belt 351, there are located fixed idler rollers 361, 362 and 363 which provide rolling support for the traction belts along the length of the sled. If desired, these idlers may be biased towards the fixed guide 353 to vary the pressing force of the traction belts against sheets being accumulated along the length of the sled. To keep the traction belts taut, tension rollers 356 are located at the bottom of the sled, and also form part of the sled guide construction. However, the traction belts 351 and their supportive idler rollers 361, 362, 363 are not entirely fixed relative to the sled, but have a degree of freedom of movement relative to the guiding surface of the sled. Being able to retract the sled is particularly effective for allowing obstructive elements, such as staples or paper clips attached to the sheets, to pass through the accumulator 350. By linking the plate to the gate so that it retracts when the gate is opened, large packs with staples can pass through without suffering damage or restriction. This also means that when the sled is in the retracted position (
A maximum gap of 3 mm is available for the accumulation chamber 364, with the sled guide 352 in the accumulation position, before compromising paper column strength. A sophisticated design is, therefore, required to avoid the cumulative tolerances of the multiple components from becoming an issue. To achieve this, the idlers 361, 362, 363 are mounted in slots 375 in a sled 352 (
The fixed guide 353, which works in conjunction with the movable sled, comprises a plurality of spring-loaded biased idler rollers 365, 366, 367 located opposite each of the idler rollers 361, 362, 363 of the sled, and serving to compress the traction belt 351 between the two sets of idler rollers. Thus, any sheet material entering the accumulation chamber 364 between the fixed guide 353 and the movable sled 352 will be forced into pressing engagement with the traction belt by the two sets of idler rollers.
The distance “t” (
By making the sled stand off from its opposite paper path by a very small amount, a gap is created. This allows, for example, paper to pass along accumulation chamber 364, reach the hard stop created by gate 354 and become accumulated without the paper being exposed to a high compressive normal force. A very large spring force can then be applied to the sled to resist being pushed off by a buckle starting to form in a sheet. This means that although the friction between belt 351 and the sheet is minimised, the paper is prevented from buckling excessively, therefore retaining the majority of its column strength.
Once the collation has been accumulated within the accumulator, forming a near-vertical stack, the accumulation gate 354 is opened to allow the accumulated collation to pass downwardly toward the sheet folding mechanism 500. As discussed above, the accumulated collation has a natural acceleration due to gravity of 1 g. In previous devices, acceleration of approximately 1 g was achieved for horizontal acceleration of the collation without shearing or shingling of the accumulated collations. With the vertical accumulator an acceleration of around 2 g can be utilised, by using gravitational as well as mechanical forcing, thus improving the volume-throughput of the machine.
As an alternative to an accumulation gate, it is possible to use a pair of pinch rollers which remain static during the accumulation process to halt the sheets, but are then rotated in order to assist the acceleration of the collation once accumulation has been completed.
Instead of a pair of traction belts 351, an alternative sheet-driving system may be employed within the accumulator, for example consisting of a single belt or of a plurality of belts, arranged either in parallel, in series, or as a combination of the two. It should also be noted that the use of belts is not necessary, and the sheets could be driven by a series of drive rollers or other such alternative means known to those skilled in the art. Similarly, it is not necessary for the belts or rollers to be aligned to drive precisely in the sheet-feeding direction through the accumulator, and they may, desirably in some cases, be aligned at an angle to the sheet-feed direction.
In the foregoing, there has been described a method of preventing single or multiple sheets of paper from reaching critical buckling and crumpling when compressed lengthways against a hard stop or gate 354 by traction belts 351. The paper buckle is restrained by the very close proximity of the two sides of the paper path. Making one side of the paper path as a sled 351 which can be retracted allows sheets with oversized features such as staples to pass. Opening the gate and retracting the sled in a coordinated movement, enables the lead edge of the sheets to be swept clearly off the gate surface, preventing damage of the sheets. The sled mechanism does not need to be linked directly to the gate, and an independent drive system or actuator could perform the same function of retracting the gate, but at increased cost and complexity of control.
The disclosed embodiment has a high robustness to tolerance, and enables the sled guide assembly SG to be mounted on a frame that opens, allowing an operator ease of access for clearing jams.
As described above, paper buckling is prevented by holding it nearly flat, without applying any direct pressure. This reduces the sheet to sheet friction that can prevent the individual sheets rotating relative to each other whilst being aligned to an end stop. Reducing this “resistance to deskew” allows a greater robustness to variation in the drive forces, deriving from production tolerances and wear related changes in friction, thus creating a machine which is ultimately lower cost, more reliable, runs for a longer life between services and can process a greater range of materials.
