Patent Description:
More specifically, the invention relates to a plant and a method for producing printed books using digital technologies, in which the plant comprises one or more book block forming stations, one or more cover binding machines for assembling the book blocks with respective covers and accumulation and transport means for receiving the book blocks provided by the forming stations and transferring them to the binding machines, and wherein the book blocks have corresponding book graphic codes and the covers have respective cover codes univocally associated with the respective book codes according to the introductory part of the main claims.

Typically, a book comprises a plurality of sheets with the text pages constituting a book block, and a cover superimposed on the first and last sheets and the rib of the book block. In unbound or paperback books, the assembly of the book blocks with the respective covers is carried out by perfect binders set for the series bonding of the ribs of the book blocks to the spines of the covers. In bound books, the assembly of the book blocks with the covers is carried out by cashing machines.

With the progress of laser or ink jet printing techniques and the use of flexible-setting perfect binders, it has been possible to print on-demand books, allowing the production, at low costs, of books in very limited quantities or with single copy. An example of a book packaging system on demand with production of book blocks and covers and their assembly is represented by the European patent <CIT>.

The productions of on-demand book to be economically competitive require that the plants use a limited amount of manpower and in which the book block forming stations and the perfect binders or more generally the cover binding machines, which represent the most expensive components of the plant, can operate in an optimized manner with very limited dead times, especially during periods of maximum production.

The book block forming stations produce, for example, printed book blocks with digital technologies using a printing line starting from a printed paper roll or from a non-printed paper roll and subsequent printing, with following cutting and stacking of sheets or signatures. For the production of books, the forming stations can be connected to the perfect binders or to the cover binding machines either on-line or off-line, both with problems.

In the on-line connection, such as for example in the plant of the patent <CIT>, a book block forming station and a perfect binder operate in synchronism. The functional speed of the system is the one of the slowest component and the stopping of one of the components causes the stopping of the entire plant.

The effects of stops or delays in the book block forming station or in the perfect binder can be attenuated by providing a buffer transport between the two components. An example of this solution is known from <CIT>, in which a two-plane transport table with buffer function is inserted between two book block forming stations and a perfect binder. This structure allows the decoupling between the printing line and the binder, but the plant can continue to operate only for rather limited periods of time, for example during stops due to a replacement of the paper roll in the printing line or a change in the type of cover in the perfect binder.

In the off-line connection between book block forming station and binding machine, the book blocks of the forming stations are sequentially collected on pallets and extracted from the pallets in a suitable manner to be transferred to the binders. The operations of loading and unloading the book blocks are very critical for the intrinsic compliance of the blocks and difficulty of the book blocks being drawn from below or from above.

Moreover, such operations require either a lot of manpower in the case of manual operations and/or the use of expensive robots in the case of automated operations.

<CIT> discloses a plant for the production of books printed with digital technologies comprising one or more book block forming stations, one or more cover binding machines for assembling the book blocks with respective covers, and accumulation and transport means for receiving the book blocks supplied by the forming stations, and in which the book blocks have corresponding graphic book codes while the covers have respective cover codes associated with the respective book codes of a given work order, wherein: the accumulation and transport means comprise one spiral tower, in which the tower has a conveyor that can be moved along a multi-level spiral path, a conveyor moving group; the tower has a function of temporary storage for the book blocks along the spiral path; and said plant has an electronic center with a server.

An object of the invention is to provide a system and method for producing printed books with digital technologies which use one or more book block forming stations and one or more perfect binders or sheers for assembling the book blocks with respective covers, which are completely uncoupled, of relatively low cost, allowing a great operating flexibility, with very limited dead times and requiring a small amount of manpower.

In accordance with this object, the plant accumulation and transportation means comprise a plurality of spiral towers, wherein each tower has a conveyor belt that can be moved along a multi-level spiral path, a belt moving group and an electronic control unit for the motorization group. Each tower has a function of temporary storage for the book blocks along the spiral path and capability of movement between loading areas adjacent to the forming stations and unloading areas adjacent to the cover binding machines and in which the electronic control units, in the loading areas, set up the towers for receiving and storing in an orderly way along the conveyor belt the book blocks from the forming stations, while, in the unloading areas, the electronic units set up the towers for feeding the cover binding machines with the stored book blocks. The electronic control units are provided for obtaining and storing databases of identification for the stored book blocks; and the plant has an electronic center, interfaced with the electronic control units of the spiral towers and the cover binding machines for taking charge loading data and for a functional coupling of the loaded towers with the cover binding machines jointly with the working order.

According to another feature, the accumulation and transport means comprise a plurality of spiral towers and in which each tower includes a conveyor belt that can be moved along a spiral path, a belt motorization group and an electronic control unit for the motorization group. Each spiral tower has the function of a temporary storage for the book blocks along the spiral path and capability of movement between a loading area adjacent to the forming station or each forming station and an unloading area adjacent to the cover binding machine or each cover binding machine and in which, in the loading area, the tower is designed for serially receiving and storing the book blocks from the forming station while, in the unloading area, the tower is designed for feeding the cover binding machine with the stored book blocks. The electronic control unit, on the basis of a loading program, responds to information from the forming station and information on dimensional characteristics of a book block emerging from said station for driving the belt motorization group with movement of the conveyor belt such as to arrange the book blocks in an optimized way along the spiral path of the belt, regardless of the size and the time of formation of the book block; and in which the electronic control unit, on the basis of an unloading program, responds to information from the cover binding machine and information on the characteristics of an emerging book block for moving the conveyor belt so as to feed said binding machine with the emerging book block.

In accordance with a further feature, the invention relates to a spiral tower for graphic blocks in a book production plant, in which the tower is used for storing, along a spiral path, graphic blocks of different sizes emerging from a block forming station, The tower has the capability of movement between a loading area of the plant adjacent to the block formation station and an unloading area. An initial section of the spiral path is designed for serially receiving and storing the graphic blocks from the forming station while, in the unloading area, the tower is set up for unloading the graphic blocks from the spiral path towards an user apparatus. An electronic control unit of the tower responds to information on the graphic block emerging from the forming station to drive a motorization group with movement of the conveyor belt such as to arrange the graphic blocks in an optimized way along the spiral path regardless of the size of the graphic blocks and from the time of formation of the blocks.

A plant of these typologies ensures a high production flexibility, with minimum manpower engagement and very limited dead times for the forming stations and for the cover binding machines.

The method of producing books printed with digital technologies of the invention employs a plant comprising one or more book block forming stations, one or more cover binding machines and accumulation and transport means between the forming stations and the cover binding machines. Book blocks and covers have book graphic codes and cover codes associated univocally in a given working order. The accumulation and transport means comprise a plurality of spiral towers, in which each tower has a conveyor belt, a belt moving group and an electronic control unit and capability of movement between loading areas adjacent to the forming stations and unloading areas adjacent to the cover binding machines, while the plant has an electronic center interfaced with the electronic control units of the towers and with the binding machines. The production method comprises in particular the steps:.

The characteristics of the invention will become clear from the following description, given as a non-limiting example, with reference to the attached drawings, in which:.

With reference to <FIG>, <NUM> represents a production plant for books <NUM> printed with digital technologies, comprising an industrial space <NUM> for book block forming stations <NUM>, perfect binders <NUM> for book block covers, with trilateral trimmers (not shown), accumulation and transport means <NUM> and an electronic center <NUM>.

As far as the present invention is concerned, the book block forming stations <NUM> and the perfect binders <NUM> with the trimmers can be of the type described in the aforementioned patent <CIT>, the contents of which are incorporated herein and the description of which is omitted.

The production plant <NUM> may comprise formation stations for book blocks to be bound of a different type and also stations for forming sewn book blocks and in which the cover binding machines are constituted by cashing machines for hardcover books. From here on, without departing from the scope of the invention, reference will be made only to formation stations for book blocks with single sheets or signatures, to be assembled by means of perfect binders with the respective covers.

In the production plant <NUM>, each book <NUM> is produced on demand according to a given working order represented by a single identification number and comprises a book block <NUM> and a cover <NUM> obtained from a cover sheet 33a. The book block <NUM> and the cover <NUM> are identified by a graphic book code <NUM> and, respectively, by a graphic cover code <NUM>, such as an optically readable Barcode or Data Matrix. The book code <NUM> includes book-specific information and dimensional information thereof, while the cover code <NUM> includes data of matching with the respective book block.

The book block forming station <NUM>, as in the patent <CIT>, comprises a high-speed printer fed by a spool of blank paper and wherein, on the basis of the working order and a file with book-specific data, the printer performs printing of the sheets. The sheets are then separated and stacked by corresponding cutting and stacking devices of the book block forming station and then fed through an output gate <NUM>. Naturally, for book blocks formed by superimposed signatures, the cutting device separates the constituent sheets of the signatures, while the book block forming stations <NUM> have devices for folding such sheets.

Inter alia, the production plant <NUM> may provide book block forming stations without printers. In this alternative, the forming stations are fed by paper rolls in which the sheets of the book blocks regarding the various working orders have been previously printed in sequence. The book block forming stations therefore have only cutting devices, or cutting and bending devices for the signatures, and stacking and forwarding devices.

According to a known technique, the perfect binders <NUM> receive the book blocks <NUM> from an input gate <NUM>, deposit a layer of glue on a rib of the received blocks and assemble the book blocks with the cover <NUM> obtained by folding of the cover sheet 33a. After drying the glue, the book <NUM> is trimmed by a trilateral trimming machine and forwarded for palletizing and transport in accordance with the working order. The cover sheets 33a are generally obtained, by cutting, from reels printed with their respective contents and arranged in a sequence according to the working order for a coupling consistent with the sequence of the book blocks received from the forming station <NUM>.

The accumulation and transport means <NUM> are provided for accommodating the book blocks <NUM> emerging from the output gates <NUM> of the forming stations <NUM> and suitably transferring the received blocks <NUM> to the input gate <NUM> of the perfect binders <NUM>.

According to the invention, the accumulation and transport means <NUM> comprise a plurality of spiral towers <NUM> (<FIG> and <FIG>) and in which each tower has a platform <NUM>, a support structure <NUM>, a conveyor belt <NUM>, a motorization group for the conveyor belt comprising a motor <NUM>, an electronic control unit <NUM> and a display <NUM>.

The support structure <NUM> defines, for the conveyor belt <NUM>, a spiral path "SP" with multiple levels and a recovery path "RP". The conveyor belt <NUM> can be moved along the spiral path "SP" from an initial section defining a tower input <NUM> in a lower portion of the path to a terminal section <NUM> in a higher portion of the path. The recovery path "RP" (shown only in part) of the conveyor belt <NUM> comprises a vertical portion which descends from the terminal section <NUM> and a horizontal portion which is directed toward the tower input <NUM>. Generally, the terminal section <NUM> of the path "SP" also represents an output for the book blocks <NUM> emerging from the tower <NUM>.

Each spiral tower <NUM> has a function of temporary storage for the book blocks <NUM> along the spiral path "SP" and capability of movement in the industrial space <NUM> between loading areas <NUM> (see <FIG>) adjacent to the book block forming stations <NUM>, unloading areas <NUM> adjacent to the perfect binders <NUM> and a parking area <NUM>.

Intermediate conveyor belts <NUM> and intermediate conveyor belts <NUM>, respectively, are also provided for transferring the book blocks <NUM> between the forming stations <NUM> and the towers <NUM> and between the towers and the binders <NUM> to compensate for the different heights from the ground between the output gates <NUM> of the book block forming stations <NUM> and of the tower inputs <NUM> and between the outputs of the towers <NUM> and the input gates <NUM> of the binders <NUM>.

Conveniently, each spiral tower <NUM> comprises an RFID tag <NUM>, while the plant <NUM> comprises a series of antennas <NUM> and ports <NUM> located in significant areas in the space <NUM> and connected to the electronic center <NUM>. An operator of the electronic center <NUM> therefore has the possibility of knowing the position of each tower <NUM> with respect to the areas <NUM>, <NUM> and <NUM>.

In the loading areas <NUM>, the spiral towers <NUM> can be connected to the forming stations <NUM> for requesting the forwarding of book blocks <NUM> on the output gates <NUM>. In turn, the electronic control units <NUM> are programmed for enabling the towers <NUM> to receive the book blocks <NUM> serially and store them in an optimized manner along the conveyor belt <NUM>. Moreover, the electronic units <NUM> are provided for forming and storing databases identifying the stored book blocks.

In the unloading areas <NUM>, the spiral towers <NUM> can be connected to the perfect binders <NUM> for forwarding, on request, the stored book blocks <NUM>, while the electronic units <NUM> pre-set the towers to feed the binders <NUM> with the book blocks stored for their processing and updating the respective database.

By means of an appropriate organization and an adequate quantity, the spiral towers <NUM> therefore ensure operations, without downtime, of the book block forming stations <NUM> and the perfect binders <NUM>.

The book block forming stations <NUM> operate in fact with a forwarding rhythm of the book blocks <NUM> strongly variable depending on the number of sheets which constitutes the block: High rhythm for book blocks with reduced number of sheets and progressively lower rhythm for book blocks with high number of sheets. On the other hand, the perfect binders <NUM> have working times which are substantially independent of the number of sheets of the book blocks to be bound. Moreover, both the book block forming stations and the perfect binders can be subjected to temporary stops, with consequent shutdown of the plant.

The towers <NUM> are designed for storing without stopping the book blocks formed by the stations <NUM> and, at different times, for feeding the perfect binders <NUM> with the stored book blocks, according to their specific rhythm, compensating for the different velocities and temporary stops.

Conveniently, the spiral towers <NUM> comprise one or more respective detection devices for obtaining identification data of the book blocks <NUM> received and to be delivered. To this end, at the tower input <NUM> there is provided a portal provided with an optical reader <NUM> for reading the book code <NUM> and with a three-dimensional scanner <NUM> and relative controllers for determining dimensional and identification information of the received book blocks <NUM>. The terminal section <NUM> in turn provides a portal with an optical reader <NUM>.

For some configurations of the production plant <NUM>, the spiral towers <NUM> operate in a direct mode. The unloading of the book blocks is carried out by moving the conveyor belt <NUM> in the same direction as the loading, according to output logic "FIFO", through the terminal section <NUM> which defines an output of the tower. The optical reader <NUM> detects the identification data of the book block <NUM> present in the terminal section <NUM> for delivery to the input gate <NUM> of the perfect binder <NUM> after checking of the correct matching with the cover code <NUM> of the book to be produced.

For other configurations of the system <NUM>, the towers <NUM> operate in an inverted mode. The blocks are unloaded by moving the belt <NUM> in the direction opposite to the loading direction, according to output logic "LIFO", through the tower input <NUM>. This configuration enables the book blocks to be delivered to the perfect binders at a reduced height with respect to the ground, allowing to use spiral towers of relevant height, without the need for compensatory transport connections between the outputs of the towers and the input gates <NUM> of the binders. As for the inverted mode, the identification data of the book blocks <NUM> to be delivered to the binder <NUM> are consequently obtained by the optical reader <NUM> of the tower input <NUM>.

In the production plant <NUM>, the electronic center <NUM> is connected to the book box forming stations <NUM> and to the perfect binders <NUM> and includes a server interfaced through a Wi-Fi network with the control units <NUM> of the spiral towers <NUM> for a survey of the loading data and for a functional coupling of the towers loaded with the binders <NUM>. This is in accordance with a given working order, for example read from a data file sent to the binder. Moreover, the electronic center <NUM> is interfaced with the electronic management network of the plant in order to obtain in real time the data of the production and the content of the various towers <NUM> with the relative data.

Each spiral tower <NUM> provides for the electronic unit <NUM> an "LP" loading optimization program, with which the electronic unit is configured in response to reading the book code <NUM> and dimensional scanning, forming a file containing the working order data, marked by a unique customer code and loading the display <NUM> with work information and the total quantity of books that the tower can store.

In accordance with the "LP" program and in response to receipt of a book block <NUM> on the conveyor belt <NUM> and to information from the optical reader <NUM> and the three-dimensional scanner <NUM>, the electronic unit <NUM> drives the motorization group so as to arrange the book blocks <NUM> along the conveyer belt <NUM> with optimized spacing. The book blocks can be arranged at a short distance from each other, or scaled with partial overlap, when this is possible compatibly with the thickness of the book blocks and the distance between the coils of the spiral path "SP".

The movement of the conveyor belt <NUM> is intermittent and at high speed, independent of the delivery rate of the book block forming station <NUM> and can continue until the detection of a book block at the terminal section <NUM>, indicating the completion of the loading, with a consequent stop command of the belt <NUM>.

In accordance with an "UP" unloading program, the electronic control unit <NUM> of the tower <NUM>, upon request of the perfect binder <NUM>, responds to the information from the book code <NUM> of the book block <NUM> to be bound and, in a slave mode after confirmation, moves the conveyor belt, forwarding the book block for delivery. In addition, the electronic unit <NUM> updates the database of the stored book blocks and the display <NUM> with the updated information until the last book block <NUM> has been delivered and the conveyor belt <NUM> is arrested.

In the production plant <NUM>, one or more forming stations <NUM> and/or one or more perfect binders <NUM> can each be connected to a pair of spiral towers <NUM>, one of which is operative and another is in standby. To this end, intermediate dubbed conveyor belts <NUM> and <NUM> are provided (<FIG>) with two branches, which are coupled "in tandem", respectively, with the output gates <NUM> of the stations <NUM> and with the input gates <NUM> of the binders <NUM> through exchange conveyor mechanisms <NUM> and <NUM>. The two branches of the conveyor belts <NUM> can be connected to the "tandem" towers lying in the loading area <NUM>, while, respectively, the two branches of the belts <NUM> can be connected to the "tandem" towers lying in the unloading area <NUM>.

With the use of the dubbed conveyor belts <NUM>, the book block forming stations <NUM> can be connected with a pair of spiral towers <NUM> in the loading area <NUM>, of which an operating tower is loading and an empty tower is waiting. In response to "full tower" information from the operating tower, the exchange mechanism <NUM> is switchable for directing the book blocks <NUM> toward the belt branch <NUM> connected to the waiting tower <NUM>. The already waiting tower becomes operative and will begin to collect the book blocks <NUM>, allowing an operator to replace the full tower with an empty one, without substantial slowing down in the forwarding of the book blocks formed by the station <NUM>.

In turn, the dubbed conveyor belts <NUM> allow the perfect binders <NUM> to be connected in the unloading area <NUM> with a pair of spiral towers <NUM>, of which an operating tower will be unloaded and a full tower will be waiting. In response to "empty tower" information of the operating tower, the exchange mechanism <NUM> is switchable to place the input gate <NUM> of the perfect binder <NUM> in connection with the branch of the belt <NUM> connected to the waiting tower <NUM>. The already waiting tower <NUM> becomes operative and will forward the stored book blocks <NUM> toward the binder, allowing an operator to replace the empty tower with a full one, without substantial slowing down of the same perfect binder <NUM>.

Each spiral tower <NUM> can load book blocks <NUM> of several working orders for feeding a book block with covers of the same working orders or for feeding multiple perfect binders with covers of the corresponding working orders.

The production plant <NUM> can employ a set of spiral towers <NUM> of different typologies with respect to the spacing of the coils, the storage capacity and the possibility of loading book blocks belonging to different working orders.

According to a feature of the invention, the server of the electronic center <NUM> can operate with a best tower program which suggests which tower is best for executing a given working order.

In summary, the best tower program proposes the solution optimized for the selection of spiral towers taking into account:.

As regards the displacement capability, the spiral towers <NUM> are provided with easy displacement means.

Specifically, in each tower <NUM>, the platform <NUM>, of substantially rectangular shape, is supported by four multi-directional wheels <NUM> (<FIG>) and a pair of swiveling wheels <NUM> mounted at the corners and in a central section, respectively. For some types of spiral tower, the platform <NUM> further comprises, in a lower section, two housings <NUM> and <NUM> in which batteries <NUM> are lodged. The swiveling wheels <NUM> are motorized with feeding from the batteries <NUM> to carry out easy movements of the towers among the loading areas <NUM>, the unloading areas <NUM> and the parking areas <NUM>.

The platforms <NUM> of the spiral towers <NUM> also define pairs of positioning seats <NUM> while anchoring blocks <NUM> (see <FIG> and <FIG>) are fixed in the loading areas <NUM> and the unloading areas <NUM>. The blocks <NUM> have teeth <NUM> with profiles substantially complementary to those of the seats <NUM> for a stable and precise positioning of the towers <NUM> with respect to the forming stations <NUM> and to the binders <NUM>. In the loading areas <NUM>, the seats <NUM> of the platforms <NUM> can be coupled with the teeth <NUM> of the blocks <NUM>, aligning the tower input <NUM> with the output gate <NUM> of the forming station <NUM> with locking of the tower. Similarly, in the unloading areas <NUM>, the positioning seats <NUM> can be coupled with the teeth <NUM> by aligning the output of the tower <NUM> with the input gate <NUM> of the binder <NUM> and the locking of the tower.

In the platforms <NUM> there are electric sockets <NUM> (<FIG>, <FIG>) connected to the motor <NUM> for moving the conveyor belt <NUM> and to a power supply for recharging the batteries <NUM>. The sockets <NUM> can be connected to cables not shown of the book block forming stations <NUM> and of the perfect binders <NUM> for the operation of the towers in the loading areas <NUM> and <NUM>. In the parking area <NUM>, the sockets <NUM> can be connected for recharging the batteries <NUM> with one or more supply towers <NUM>. Alternatively, the electrical supply of the towers <NUM> can be carried out, together with the physical connection between blocks <NUM> and towers, by means of electrical arrangement between the teeth <NUM> of the blocks <NUM> and the positioning seats <NUM>.

The platforms <NUM> also include data sockets <NUM> connected to the electronic control units <NUM>. The data sockets <NUM> can be connected to data cables not shown of the forming stations <NUM> and of the binders <NUM> for the exchange of information functional to the loading and unloading operations.

In a simplified form, the spiral towers <NUM> are not provided with autonomous movement features and their displacement capacity can be obtained by using the platforms <NUM> as pallets of one or more forklift trucks.

The spiral towers <NUM> can also load graphic blocks in automated publishing systems in different and/or subsequent working steps with respect to those of the assembly between book blocks and covers. This is the case, for example, of extra work on block books, such as wrapping, cutting, coating, etc. or in the case of "semi-bound" books for a rigid cover. For such work, the spiral tower can be loaded again with bookbound books.

The spiral towers <NUM> so far described and shown in <FIG> are of an elongated type and in which the coils have in section two circular sectors connected with two straight portions. The height of the towers can be limited so as to obtain a facilitated coupling with the perfect binders and a good storage capacity.

Without this representing a limitation of the scope of the invention and purely by way of orientation, the spiral towers <NUM> have a width of <NUM>, a length of <NUM> and a height of <NUM>, for a distance of about <NUM> between the coils of the spiral path "SP".

The production plant <NUM> may also use as accumulation and transport means, alternatively or in combination with the spiral towers <NUM>, circular spiral towers <NUM> of <FIG> or double spiral towers <NUM> of <FIG>, <FIG> and <FIG>.

The circular spiral towers <NUM> (<FIG>) have a structure similar to that of the towers <NUM>, but the coils of the spiral path have no rectilinear segments and are developed in height. Their use is generally connected to the output mode "LIFO", using the tower input <NUM> as the output gate of the book blocks <NUM>, with the reversal of the direction of motion of the conveyor belts. Height and diameter of the towers <NUM> can be modulated according to the storage requirements.

The double spiral towers <NUM> (<FIG>) each include two spiral towers <NUM> and <NUM> of which the tower <NUM> has a conveyor belt <NUM> with salient spiral and the tower <NUM> has a conveyor belt <NUM> with descendent spiral. The double tower <NUM> has a platform <NUM> similar to the platform <NUM> of the towers <NUM> and with output gate and functional components equal to those of the towers <NUM> and which maintain the same numbering.

The upper section of the conveyor belt <NUM> is connected to the upper section of the conveyor belt <NUM>. The book blocks <NUM>, after the tower <NUM> has been filled with a salient shifting through the tower input <NUM>, are stored in the tower <NUM> with descendent shifting up to a tower output <NUM>. The number of coils of the tower <NUM> can be limited so as to have the tower output <NUM> at the same height from the ground as the input gates <NUM> of the perfect binders <NUM>.

In the double spiral tower <NUM>, the conveyor belt recovery path <NUM> includes a vertical section descending from the uppermost portion and a horizontal section toward the tower input <NUM>. The recovery path of the conveyor belt <NUM> includes a horizontal section from the tower output <NUM> and a vertical section salient from the horizontal section to the uppermost portion. The motorization groups for moving the conveyor belts <NUM> and <NUM> are suitably synchronized: when a book block arrives, with a salient shifting up to the upper portion of the conveyor belt <NUM>, the block is received and dragged by the conveyor belt <NUM> with a descendent shifting up to the tower output <NUM>. The overall spiral path of the tower <NUM>, intended for storage of the book blocks, is therefore constituted by the salient spiral portion of the belt <NUM> and by the descending spiral portion of the belt <NUM>.

The spiral towers <NUM> can be connected to the book block forming stations <NUM> by means of respective intermediate conveyor belts <NUM> (<FIG>). The belts <NUM> are suitably inclined to compensate for different heights between the output gates <NUM> of the book block forming stations <NUM> and the tower inputs <NUM>. For the connection of the spiral towers <NUM> with the perfect binders <NUM>, the intermediate conveyor belt (not shown), on the other hand is substantially horizontal.

The double spiral towers <NUM> also have the possibility of being connected in "tandem" with the forming stations <NUM> and the binders <NUM> by means of a switching mechanism and a dubbed conveyor belt. <FIG> shows the "tandem" connection of two double spiral towers <NUM> with a dubbed conveyor belt <NUM> and a switching mechanism <NUM> for feeding a perfect binder <NUM>.

The operation of the production plant <NUM>, in its main parts, provides the pre-set for loading of an empty tower <NUM> (<FIG> and <FIG>) present in the loading area <NUM>, by connecting the tower input <NUM> with the output gate <NUM> of the book block forming station <NUM> and interfacing the electronic control unit <NUM> with the forming station <NUM> for detecting synchronization information thereof.

Upon receipt at the tower input <NUM> of a book block <NUM> to be loaded, the optical reader <NUM> and the scanner <NUM> detect the characteristics of the book block and transmit them to the electronic control unit <NUM>. On the basis of the "LP" loading program, the electronic unit <NUM> drives the motor <NUM> of the motorization group for incrementally moving the conveyor belt <NUM>. This can occur with a minimum spacing with respect to a book block previously loaded or scaled along the conveyor belt, with a substantially constant degree of overlapping, independently of thickness and size of the book blocks.

The book blocks <NUM> are loaded, one after the other, until the loading is completed for a given working order or, when this is not possible, until the tower is filled. In accordance with instructions from the electronic center <NUM>, for use with a single tower, the operator disconnects and moves the full tower away from the output gate <NUM> and prepares for loading, connecting it to the door <NUM>, an empty tower already present in the loading area <NUM> or moving it in this area from the parking area <NUM> or from one of the unloading areas <NUM>.

Following the instructions of the electronic center <NUM>, the operator then shifts the full tower of the loading area <NUM> into the unloading area <NUM> of the perfect binder <NUM> as indicated in the working order or in the parking area <NUM>.

For assembly between book blocks and covers, the operator must prepare for unloading the full tower already present in the unloading area <NUM> or after having picked up and positioned the designated tower from the parking area <NUM>. This, by connecting the tower output to the input gate <NUM> of the perfect binder <NUM> and interfacing the electronic control unit <NUM> with the binder <NUM> for an exchange of information.

On the basis of a request by the perfect binder <NUM>, of the unloading program "UP", the information from the output reader <NUM> and the matching between the book code <NUM> and the cover code <NUM>, the electronic unit <NUM> activates the motor <NUM> of the motorization group. For the feeding the binder <NUM>, the book blocks are removed from the minimum distance or scaled arrangement with incremental movement of the conveyor belt <NUM>. This is based on the book block information and information from the output optical reader <NUM>.

According to the working order, the book blocks <NUM> are unloaded in succession until the tower is emptied. In the case of a single tower, the operator disconnects and moves the full tower away from the input gate <NUM> and can now arrange for unloading a full tower present in the unloading area <NUM> or by moving it from the parking area <NUM> or from the loading area <NUM>. The emptied tower present in the unloading area <NUM> can be moved into the loading area <NUM> or into the parking area <NUM>.

In the case of use of "tandem" towers <NUM>, the loading and unloading operations are simplified and accelerated for the exchanges between operating towers and waiting towers made possible by the switching mechanisms <NUM> and <NUM>.

The operation of the towers <NUM> and of the towers <NUM>, with the modifications of the case, is quite similar to that of the towers <NUM> and, for brevity, has been omitted.

Naturally, the principle of the invention remaining the same, the embodiments and details of construction may be varied widely with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the present invention.

In particular, the intermediate conveyor belts <NUM> between the book block forming stations <NUM> and the spiral towers <NUM>, <NUM> and <NUM> may be constituted by buffer conveyor belts (not shown) or be integrated with such belts. Under normal operating conditions, the buffer belt moves at a speed higher than that of the tower conveyor belt. Due to slowing down or stopping of the tower, the buffer strip slows down, temporarily accumulating the blocks and returns to the steady speed upon restoring normal operating conditions. If the buffer strip is full and the tower has not been reactivated, the forming station is also stopped.

The buffer conveyor belts can also be combined with the dubbed conveyor belts <NUM> for "tandem" towers. Thus, the buffer belts can retain the book blocks intended for a fully charged tower, in view of the subsequent deviation of the book blocks toward the empty tower, without stopping the forming station <NUM>.

The spiral towers <NUM>, <NUM> and <NUM> can also be loaded manually. The "LP" loading program will measure the book for an optimized advancement of the tower conveyor belt, with the possibility for the operator to overwrite the values. The operator can also cause the input optical readers <NUM> to read the book code <NUM> also in manual mode, without the processing of the "LP" program. The display <NUM> will show the same information shown for automatic loading based on the stated values.

Claim 1:
A plant (<NUM>) for the production of books (<NUM>) printed with digital technologies comprising one or more book block forming stations (<NUM>), one or more cover binding machines (<NUM>) for assembling the book blocks (<NUM>) with respective covers (<NUM>), and accumulation and transport means (<NUM>) for receiving the book blocks supplied by the forming stations and transferring the book blocks to the cover binding machines, and in which the book blocks have corresponding graphic book codes while the covers have respective cover codes associated with the respective book codes of a given working order, wherein
the accumulation and transport means comprise a plurality of spiral towers (<NUM>), in which each tower has a conveyor belt (<NUM>) that can be moved along a multi-level spiral path, a belt moving group (<NUM>) and an electronic control unit (<NUM>) for the belt moving group;
each tower has a function of temporary storage for the book blocks along the spiral path and capability of movement between loading areas (<NUM>) adjacent to the forming stations and unloading areas (<NUM>) adjacent to the cover binding machines and in which the electronic control units, in the loading areas, can set up the towers for receiving and storing in an orderly way along the conveyor belt the book blocks from the forming stations, while, in the unloading areas, the electronic units can set up the towers for feeding the cover binding machines with the stored book blocks;
the electronic control units are provided for obtaining and storing databases of identification for the stored book blocks; and
said plant has an electronic center (<NUM>) with a server, interfaced with the electronic control units of the spiral towers and the cover binding machines for taking charge loading data and for a functional coupling of the loaded towers with the cover binding machines jointly with the working order.