This invention relates to the field of printing: to one or more components of a system for creating bound books or sections of books from primarily, but not exclusively, small-format sheets. Within the industry, a stack of sheets may variously be referred to as a book, book-set, booklet or brochure. Unless explicitly stated, this invention is applicable to all such stacks of sheets and no distinction is intended by the differing terminology that may be used.

Technological advances in digital printing have led to significant changes in the commercial printing industry, to the extent that there are now various options by which books or booklets may be printed and bound.

In conventional "offset" printing processes, a press produces a series of multiple copies of each page-sheet. One example of offset printing, with which this invention is primarily concerned, is small-format printing. For small-format printing a page-sheet is typically a double-sided printed sheet, which, when folded, will create four pages of a printed book. The press is set to print the required number of copies of the first page-sheet, the copies being output to a stack. Once printing of this first page-sheet is complete, the stack is set aside and the press is reset for printing the next page- sheet. Multiple copies of a second page-sheet are printed and stacked, then the press reset for a subsequent page-sheet and so on until all pages of the book run are complete. A series of stacks ensues, with each stack comprising multiple copies of one of the page-sheets required for a complete finished book. Various methods exist for binding sets of sheets from small-format offset printers, of which the most common is 'stitch-fold-trim'. In this process, each page-sheet stack is placed into a unique station of a tower collator. In the binding process, the tower collator selects one page sheet from each station in a pre-determined order and feeds a complete set of page-sheets into a binding unit. The binding unit stitches the sheets together along a pre-determined line, using one or multiple stitches. The stitched set is then folded along the stitch line. The product may or may not be trimmed along the fore-edge to create the finished book. Books created this way, unless comprising only a few sheets, have an ill-defined crease line at the spine and tend not to lie flat. The product is of poor aesthetic appearance, cannot easily be stacked and can be difficult to pack into envelopes. An example of a product produced in this way is shown in Figure 1 .

US 7,261 ,507 describes a book binding system for use with offset printed sheets stacked in a tower collator. This binding system aims to improve the appearance of a bound booklet, particularly for larger numbers of sheets, and to increase the processing speed. In order to achieve this, sheets are fed individually or in sets, folded and then stacked along the fold line before being stitched.

Digital printing technology on the other hand allows a printed image to be changed on each consecutive sheet that is supplied to a printer without stopping the printer to fit a new printing plate. This means that the sheets of a book can be printed in sequence, allowing direct coupling of the printer to a binding machine. Digital printing therefore offers the potential for collation of consecutive printed sheets into books or booklets, offering considerable simplification to the book-making process.

An in-line digital printing and book-binding apparatus is described in PCT patent application WO 01/34403. In this, and other prior art digital printing systems, a continuous web is output from a printer that is digitally printed on both surfaces. To produce the finished book the printed web must be cut into sheets with each sheet forming two pages of the book printed on both sides. The individual sheets are then passed, at high speed, through a folding station, are collated into book sets, each set is then stitched or glued to create a bound book, which is then trimmed to final size.

An alternative printing process for small-format books is offered by the cut- sheet digital press. In this process, pre-cut sheets are printed individually and output in a pre-determined sequence. Such printers are now capable of operating at speeds sufficient that book production rates may be significantly improved by linking with an automated binding process.

To date therefore, books have tended to be produced by a binding process that is largely dictated by the method by which its pages are printed.

Binding apparatus, which carries out the stitching, folding and trimming operations has tended to develop with the whole of the apparatus geared towards one particular form of printing. With current commercial demands for less costly binding equipment, there is a need for development of a system at least some of which can be used in different print markets. By increasing the market of this part of the apparatus, it can be produced at lower unit cost. Only the remainder of the apparatus need be specific to the printing procedure with which it is intended to be used. Potentially, there is also the possibility of adapting the apparatus such that it may be used with minimal adaptation in multiple printing processes. As noted above, one commonly-used book binding system comprises a number of components that generally collate, fold, bind (or vice versa) and then trim the book. In a system according to the present invention, one of more of these components represents a novel development in itself, with the integrated system accordingly also representing a new and improved form of binding apparatus.

The present invention provides, in a first aspect, book binding apparatus for operation with at least two book-set feeding systems, of the type in which sheets are fed from multiple stacks singly and in order, the apparatus comprising:

at least two set collecting stations, arranged to collect a book-set or sub-set as it is fed from a respective feeding system and pass it to at least two respective folding stations ;

a saddle G on which sets or sub-sets are collated to form a complete book set;

a binding station at which sheets comprising the book set are fixed together;

fore- and side-edge trimming stations at which the book set is trimmed along its edge opposite a spine and edges perpendicular to the spine respectively; and

a transport system arranged to transfer the book set and / or sub-set therebetween.

This apparatus considerably improves the speed with which completed books may be produced. Each part of a book-set, coming from a different collator, is collated and folded in parallel. Timings are synchronised such that folded book sets are dropped in order onto a saddle, one on top of the other. In comparison with the prior art in which separate parts of the book are collated and folded one after the other, this present invention affords a significant increase in speed.

The transport system preferably transfers the book-set and / or sub-set in a generally linear direction between the saddle and binding station, and the book-set feeding systems feed their respective book-set or sub-set towards the saddle in a direction substantially perpendicular to the transfer direction.

Each folding station may be associated with a respective holding

mechanism, for example a sword, arranged to hold each folded book-set or sub-set above the saddle. The saddle extends longitudinally along the transfer direction, beneath these holding mechanisms, thereby allowing the folded book- or sub-set to be pushed from the sword onto the saddle.

In a particularly preferred embodiment, each book-set feeding system is a tower collator. In a second aspect, the invention provides book binding apparatus comprising:

a folding station for folding one or more printed sheets;

a saddle G on which sheets are collated to form a book set;

a binding station at which sheets comprising the book set are fixed together;

fore- and side- edge trimming stations at which the book set is trimmed along its edge opposite a spine and edges perpendicular to the spine respectively;

a transport system arranged to transfer the book-set therebetween; and an arrangement of drive mechanisms arranged to drive components of the binding station and the trimming stations;

characterised in that at least one of the drive mechanisms is independent of the remainder and of the transport system.

The transport system preferably comprises a belt made of elastomeric material, for example neoprene or polyurethane, with attached fingers arranged such that the fingers push the set of sheets as the belt is driven about a loop. The belt may be of triangular cross section such that it conveniently forms the apex of the saddle.

The transport system may also comprise a pair of independently-driven belts with respective sets of fingers arranged such that each pusher finger is aligned with a control finger such that a book set is held and guided therebetween. The side-edge trimming station may further include an arrangement of knives, at least one of which is a centre-knife located so as to cut the book- set in two, the centre-knife being under independent drive control from the rest of the knives. Embodiments of the invention will now be described by way of example only and with reference to the following drawings.

Figure 1 , as previously described, is an illustration of a book produced using a prior art small-format offset printing and binding process.

Figure 2 is a schematic representation of apparatus in accordance with this invention, in a modification suitable for binding offset printed sheets.

Figure 3 is a more detailed illustration of a saddle component of the system shown in Figure 2, in accordance with an aspect of this invention.

Figure 4 is an illustration of folded partial book-sets collated to form a complete book set on the saddle of Figure 3. Figure 5 is a reverse-angle view of a book being transferred through a stitching station, as shown in Figure 2, and in accordance with another aspect of this invention.

Figure 6 is a more detailed illustration of tucker fingers raising a stitched book towards transfer belts as shown in Figure 2 and in accordance with a further aspect of this invention.

Figure 7 is a plan view of components of a trimming station portion of the system shown in Figure 2.

With reference to Figure 2, operation of a binding apparatus that incorporates many aspects of this invention will now be described. 1 A set of sheets, A1 , comprising all or part of a book, is fed from a tower collator station, B1 to a set collecting station, C1 .

2 At station C1 the set is jogged to align the sheets.

3 The sheet set A1 is then pushed out in a perpendicular direction, D. 4 The set of sheets A1 passes through a scoring and folding station, E1

5 The folded sheet set, A1 , drops onto a sword, F1 .

6 The set is then picked up by a finger, K which carries the set away in direction L and the set drops off the end of the sword F1 and onto a saddle G.

The saddle, G, contains both fixed and moving parts: a neoprene belt H at the apex, which moves along with the book set and fixed skirts of metal (or other material), J, to hold the partially open shape of the book-set. This is shown in more detail in Figure 3. 7 One or more additional set feeder / tower collator stations (B2, B3...) have similar arrangements to transfer other partial or full book-sets (A2, A3...) via respective collecting stations (C2, C3,...), scoring and folding stations (E2, E3, ...) to respective swords (F2, F3, ). The assembly therefore comprises an arrangement of swords (F1 , F2, F3, ....) each capable of holding a partial or full book-set just above the saddle G. The skirts J of the saddle extend underneath and in line with the swords, running from the most upstream sword / collator station (F2, in Figure 2) to position P at which control is taken by belts R. For clarity of the transport mechanism, the extent of the skirts J is not shown in Figure 2. The belt H, with fingers K, runs under the arrangement of swords (F1 , F2, F3, ...), along the apex of at least part of the extent of the saddle. In this embodiment of the invention, partial book-sets A2, A3..., from successive stations, C2, C3..., each fed by a tower collator, are superimposed on saddle G to form complete book-sets A. This embodiment is shown in more detail in Figure 4. The belt H continually rotates in a loop, which in turn moves pusher fingers K to collect and transfer a sheet or stack of sheets. Timings are synchronised such that one finger K will contact and push each sub-set (A1 , A2, A3, etc.) of a book off its sword (F1 , F2) in turn. That is, upper parts of the book will only arrive at their respective swords once a previous-finger has moved on, allowing these parts to be picked up and set onto the correct position on the saddle, held and pushed along by finger K.. The near end of Figure 4 shows the spine being 'pinched' after folding, to emphasise the line of fold. Complete book sets - created either from a single station (C1 ) or from superposition of subsets (see Figure 4) from a series of stations (C1 , C2, C3...), seated on saddle G, are pushed along the saddle by the pusher fingers K towards the stitching station, M (see Figure 2). As the book set approaches the stitching station M, a second indexed set of fingers N picks up and controls the motion of the book. This is shown in further detail in Figure 5. A second neoprene belt (Figure 5a) with second pusher fingers N rotates at a slightly faster rate than the first belt K. In this way one of the set of pusher fingers N, picks up the book set and accelerates it forwards of pusher K (Figure 5b). A further set of control fingers, O, are located on a third belt, which is driven such that each pusher finger N is synchronised with a respective control finger O. The belts are driven with controlled timings and speed such that control finger O will be ahead of the sheet-set just picked up by pusher finger N, but moving at a slower speed (see Figure 5b).

Once the sheet set engages Control finger O, its speed is increased to match that of pusher finger N (see Figure 5c). In this way the position of the set is closely registered and controlled between fingers N and O. The set can therefore be accelerated and decelerated on the belt without shingling apart. This is explained in further detail below.

These second pusher belt and control belts are indexed such that the fingers accelerate and move a book-set and then decelerate and stop. Motion of these belts is therefore discrete, as opposed to the

continuous motion of belt H with pusher fingers K. The combination of fingers N and O move the book set to station M (figure 2) and arrest it at the correct location for stitches to be applied. In other embodiments, in which only single sheets are pushed along the saddle, for example when output from a digital press, then gluing may alternatively be used to bind the sheets. One or more stitches are applied by stitching heads M1 , M2... to convert the loose sheet set into a bound product. After stitching, fingers N and O retain control of the book, accelerating it forward and then arresting it at position P (see Figure 2). At position P, tucker fingers, Q, are moved upwards towards the inside of the book spine. This is shown in Figure 6. On contact, the book is pushed upwards by the tucker fingers Q, where it may be collected by transfer belts R (Figure 2) Belts R transfer the book to a fore-edge trimming station, S. 16 With reference to Figure 7, the book is held against backstops, T, and realigned by side joggers. This ensures correct position of fore-edge trim and correct alignment for subsequent side-edge trim.

17 Knife set U trims the fore-edge, with the waste dropping into a bin

beneath the machine.

18 The book is then transferred by belts V to a second trimming station, W.

19 Side trimming - and optional centre trimming - take place at station W.

20 The trimmed books are transported by belts X to a slow-moving

conveyor, Y, which therefore collects a shingle of finished books.

As will be appreciated by one skilled in the art, various modifications may be made to the embodiments shown in Figure 2. For example the tower collators B1 , B2 may be replaced by alternative collation systems that feed from multiple sets of identical sheet-pages. Each tower collator illustrated may also be replaced by a series of tower collators (not shown), linked in series to a respective set collector (C1 , C2, ....). That is, in addition to a parallel arrangement of tower collators (B1 , B2, ...) that feed sheets synchronously onto the belt H, a series arrangement of collators may, alternatively or additionally, be used to feed sheets in series to a single set collector and thereafter to belt H.

Many aspects of the above described binding system represent advances over the prior art. Of particular importance to the offset printing industry is the ability to feed sheet sets from a row of multiple tower collators to respective folding stations and thereafter deliver to the transport saddle G. In this way, each tower collator can deliver a sub-set of the same book. The sub-sets are then individually scored and folded (at station E1 , E2, etc..) and dropped onto respective swords (F1 , F2, etc.) The neoprene belt H with pusher fingers K runs underneath the swords. A pusher finger K will contact the set, say A4, on the most upstream sword F4 (not shown in Figure 2) first and push the set A4 off the sword onto the saddle G. As the belt H rotates about its loop, the finger next contacts the set A3 on sword F3. This set A3 is therefore pushed off its sword F3 and drops onto the saddle G, on top of set A4. This collection process continues until all sets (A1 to A4 in this example) are collated on the saddle.

The configuration of parallel towers is made possible by including a 90° turn between the direction in which the sheets of each sub-set are extracted and collated from the tower and the transport direction through the binding system of this invention. Sub-sets are therefore collated in parallel, before their transport direction is changed. They are effectively fed into the binding process from the side. Sub-sets are scored and folded at individual, in-line with the primary transport direction, folding stations and then held on respective swords for collection on the saddle. This arrangement is illustrated in Figure 2. It is of course noted that although Figure 2 shows only a pair of tower collators, the arrangement can be extended to three, four, five or more parallel systems.

This parallel arrangement of tower collators is to be contrasted with the known prior art which makes use of multiple towers but in a series arrangement. That is, a number of towers feed to the same folding station; all in an in-line orientation. In making a thick book therefore, either successive sub-sets can be fed sequentially through the same folding station, which reduces process speed, or the whole set may be fed but with significant loss of quality in the finished product (see Figure 1 ). By way of contrast, the present invention allows parallel tower collators and folding units to be operating concurrently. Net book throughput can therefore be doubled, trebled or quadrupled (depending on the number of towers), without loss of quality. It is not envisaged that this invention is limited to tower collators. Other known collation apparatus can be used. In small-format offset printing however, collators will generally hold multiple sets of sheets, the sheets within a set being identically printed, the sheets from separate sets then being collated to form the desired book set or sub-set. In particular, it is possible that each tower collator of the Figure 2 embodiment may be replaced with a series of tower collators that deliver book sets to the respective folding station. That is, combining the collation system described in US 7,261 ,507 with one in accordance with the present invention.

A further benefit of using a parallel tower collation arrangement is that each separate tower is readily accessible. This allows an operator to fill or re-stock one tower, whilst the other towers are feeding the binding machine. This substantially reduces downtime / time lost through sheet loading and so improves considerably overall throughput capability. As will be appreciated by one skilled in the art, it is straightforward to sequence jobs from various towers electronically.

With these two benefits alone, a binding system in accordance with the present invention offers the possibility of a far more efficient binding option for small-format offset printers. A single system can deliver high quality, thick books much faster than prior art systems as well as offering the potential for reduced loading downtime. The efficiency gain is such that, potentially, a single binding system in accordance with this invention could serve several offset printers. Each printer could have use of one or more tower collators, control of which is shared as collator output is sequenced through the binder.

It is also envisaged that instead of single sheet collators, the binding apparatus of the present invention can be applied to signature collators. That is, collators in which multiple-folded sheets of paper (signatures) are stacked and then collated. An apparatus in accordance with this invention will operate to fold each signature-set once more and then to collect multiple sets on a saddle for further processing. It is simply required that the signature, as held in the collators, is one fold away from its final in- book configuration.

Moving away from the offset printing industry, other aspects of this invention offer advantages to the binding process, regardless of the method by which the sheets are printed.

A part of the central system for transporting book sets through the binding apparatus is shown in detail in Figure 3. The system comprises a neoprene belt H to which a number of pusher fingers K are directly bonded. Bonding in this manner offers a cheap and robust construction. The belt forms a closed loop that, as it rotates, drives the pusher fingers K in the transport direction on its upper surface. An end of the loop is more clearly visible in Figure 5. The belt is roughly triangular in cross-section such that the moving belt H forms the apex of the saddle G. The remainder of the saddle is a pair of fixed skirts arranged in an inverted V- shape, with the belt running along the tip. The skirts may be made from metal or other material. In the prior art, the transport mechanism is traditionally a continuous chain, running beneath the saddle that is used to drive the pusher fingers. The chain tends to be noisy as it runs and requires lubrication and other maintenance. By way of contrast, the belt of the present invention is made of neoprene, although other elastomeric material may be equally suitable. Movement of the belt H is considerably quieter than that of the chain. This offers particular advantage if the binding apparatus is to be set up alongside an office space in which people are working. This aspect of the invention may find particular application to the cut-sheet printing processes. Moreover, the belt requires no lubrication and minimal maintenance.

It is also beneficial that the belt itself forms part of the saddle (the apex). The book therefore does not slide relative to at least the apex of the saddle for the majority of its travel. As a book is transported, marks or other blemishes may be imparted to the book by the transport system. Such marking most likely occurs at points of high friction: that is, at the apex as the book travels over the saddle in a prior art process. By ensuring that the apex of the saddle moves with the book, the incidence of marks on the book caused by the transport system is reduced.

A major problem with current binding processes is shingling of the sheets during transport. As the transport system pushes a stack of sheets, the differing coefficients of friction between the various sheets and between the inside sheet and the skirt result in differential inertial effects in different sheets, and the sheets become misaligned in the transport direction. That is, shingling occurs and the sheets in the stack are no longer sufficiently aligned. In the present apparatus, the problem is not so significant on the belt H, which rotates at a roughly constant speed. The only likely problem will occur as the book-set is picked up. However alignment at this point is not critical, and registration can be regained later by "jogging". Shingling represents a significant problem during the indexed part of the transport process, when the book-set is accelerated and decelerated and when good alignment is required for stitching. In this invention, pusher finger N and control finger O, on separate belts, are used to guide the sheets with minimal shingling.

In prior art binding systems, at stages that require closer control than permitted by a single pusher finger, a book set is guided by use of a "gripper" system. The traditional gripper system itself is bulky and has substantial inertia. In addition however, synchronisation between the stitching, side-edge and fore-edge trimming operations requires all three to be driven by a single drive unit, which is consequently large and bulky.

By way of contrast, the binding system of the present invention makes use of independent motors, which are under a central electronic control. Each element of the transport, stitching and trimming process is capable of being under independent control of one or more motors.

One aspect of the independent control provided by the present invention is demonstrated in the combination of pusher fingers N with control fingers O. Pusher fingers K drive the book sets or sub-sets in the early stages of the transportation process. As the stitching station is approached however, and alignment of the sheets within the set becomes critical to the final appearance of the product, drive control is taken up by the second set of pusher fingers N in cooperation with a set of control fingers O. The handover is shown in detail in Figure 5. As described above, fingers N and O are mounted on, or bonded to, separately driven continuous belts, which run in a loop. Drive motors and electronic controls (not shown) are arranged to drive each belt separately. Unlike belt H however, which forms part of the saddle, the N and O drive belts run underneath the saddle. Shaping of these belts is therefore not so significant. In operation, the sheet set approaches the handover point driven by pusher fingers K. The first belt (pusher belt), containing pusher fingers N, is typically driven faster than the belt H that controls movement of fingers K. Movement is synchronised such that finger N comes up from behind the sheet-set and collects it at a position just below the apex. As finger N is moving faster than finger K, the book set is moved ahead of finger K. Once it is clear, finger K reaches the end of its travel and loops around on the belt under the saddle, without contacting, and therefore disturbing, the trailing edge of the book-set. This is shown in Figure 4. The speed differential and acceleration between fingers K and N is closely controlled in order to minimise impact and possible damage to the book set. The third belt, the control belt that drives control fingers O, is driven such that, for each book set, finger O is just ahead of the sheets pushed by finger N and serves to restrain the set as it decelerates. Once in position, finger O runs synchronously with finger / belt N, thus "holding" the book and closely controlling its position.

This aspect of the invention, which makes use of a pair of fingers to control sheet alignment during transport, improves on the prior art essentially by virtue of its simplicity and cost. In this design, the forces involved are low, leading to smaller drive units with improved control. Light pusher fingers are less likely to mark the sheet-set than steel grippers, which clamp the face of the top sheet. In addition, in some embodiments, the fingers can be set to vibrate so as to "jog" the sheets into better alignment prior to stitching. Electronic control of the relative positions of pusher and control finger allows ready accommodation for books of different spine lengths. The centre point of the book's spine is the controlling factor as it is stitched, whilst it is the trailing edge that is controlled during propulsion. The different centre-to-trailing edge distances of varying book formats and trim- offs can be accommodated through electronic control of the stop points of fingers N and O. In the prior art resetting for different book formats requires operator intervention or additional servo drives.

Finally, without a bulky gripper transport system, the remaining elements of the stitching system can be aligned with a simplified geometry. An alternative option is to drive a gripper system in which individual grippers are controlled independently by electronic drive systems, rather than by a central mechanical drive. In the embodiment of the invention shown in Figure 2, separate drives operate the stitchers, fore-edge and side-edge knife units. Upstream sensors (not shown) check the integrity of each book set as it passes. If a book is wrongly collated then it is possible to suppress the stitching and knife action and individual sheet-sets may be re-fed through the system. This avoids the need for re-printing, which is a particularly valuable feature, for example, in situations in which the cover sheet is unique to a specific book.

Independent knife drives permit the reactive force to the action of each knife to be provided within the local knife-and-bed-plate unit, rather than being transmitted through the frame of the whole machine. This allows a lighter-weight construction.

A detail of the fore-edge trimming station S (see Figure 2) is shown in Figure 7. With reference first to Figure 2, the stitched book is delivered via belts R and arrested at moveable backstops T. As shown in Figure 7, the distance between backstops T and the cut line must be equal to the final book width. Unlike the prior art, station S is also fitted with side joggers and belts V (shown in Figure 2). The stitched book is "jogged" until its side-edges are correctly positioned and then held by belts V. The book is now held in the correct position for both fore-edge and side-edge trimming without the need for further alignment or adjustment. Without these joggers it is more likely that print imposition will be misaligned.

At the side-edge trimming station W, the book retains the alignment established at fore-edge station S. Regardless of book format, the book spine is transported by the belts to a set position in the station W. The side-knife assemblies are then driven independently of the transport system to cut at the book edges, a required distance from the centre. In prior art systems the knife drives are not independent of the transport system, and so the book spine position is variable. Spine position is determined by the relative set positions of the knife arrangements and timing constraints set by the transport system. It is important however to control the position of the spine during trimming as a better cut is achieved if it is clamped in a particular way. If, as with the present invention, the spine is always at the same position, regardless of book format, it can always be suitably clamped, therefore improving the appearance of the finished article.

In some embodiments of this invention it will be required also to provide a centre knife in order to cut a single book-set into multiple booklets (e.g. CD booklets). In such embodiments centre trimming is carried out at the side- edge trimming station W. In a system in accordance with this invention a centre knife may be fitted over the side-edge assembly and under independent drive control. This allows the centre-knife action to be activated or suppressed, depending on requirements. In prior art systems, a centre knife has to be fitted and set manually, which is both time- consuming and potentially dangerous. This delay and risk is therefore avoided in the present invention.

Finally, it is noted that the binding system in accordance with the present invention can be set in both left- and right-hand versions. That is, operator controls and access and final delivery conveyor can be set to either side, depending on printer / collator flow process direction.