Patent Application
20070069442
This application claims the priority of European Patent Application No. 05405536.3, filed on Sep. 12, 2005, the disclosure of which is incorporated herein by reference.
The invention relates to an apparatus for gathering and/or assembling print products or supplements, such an apparatus comprising a working belt section, forming a conveying track on a circulating conveyor traction means, which is provided with uniformly spaced-apart pushers, as well as synchronously driven feeding devices arranged along the conveying track, which differ at least in that they supply different types of print products and are connected to the conveyor by respectively one drive unit.
Machines of the aforementioned type are used in the print processing industry for gathering and assembling print products, such as printed sheets, cards, CD/DVD-ROM, or other flat objects into loose material stacks. Such machines are understood to include assemblers as well as gathering and wire-stitching machines and inserting machines. Feeding devices provided with respectively one type of print product to be assembled are arranged along a horizontal conveying track. The assembled materials are transported and moved along the conveying track by pushers attached to a circulating traction means. Depending on the design, the conveying direction for the such machines can be in a longitudinal direction of the back or transverse thereto. The design for a support mechanism positioned along the conveying track depends on the respective use.
A gathering and assembling apparatus of this type comprises an L-shaped support mechanism, consisting of an approximately perpendicular guide wall against which the print products rest with their back region and a bottom section that is slanted relative to the guide wall. Pushers or ends stops are provided against which the print products are aligned in longitudinal back direction. As a result, the gathered and assembled sheets or signatures are aligned in a longitudinal direction along the back.
A known apparatus is disclosed, for example, in Swiss reference CH 446 269 for which evenly spaced-apart pushers that are mounted on a circulating, driven traction means jointly form a conveying apparatus that pushes the assembled material stacks through a conveying channel. The compiled materials are aligned precisely with the pusher that pushes them in the conveying direction. On the path through the conveying channel, respectively one print product is deposited by each feeding device in front of a pusher, so that a completely assembled loose book block is positioned before each pusher at the end of the assembling section. Further known is a conveying apparatus where the print products are gathered and/or conveyed with the back of the print product positioned transverse to the conveying direction.
Print products for a gathering and wire-stitching operation are gathered while positioned straddling on a roof-shaped support and must be opened up individually in dead center before they are deposited on the conveyor. Their position in a transverse direction on the conveying apparatus is defined by the ridge of the roof-shaped support and an end stop or pusher in the longitudinal direction of the back.
With gathering and assembling machines used for inserting supplements, the print product feeding devices are arranged along a conveying track, wherein the so-called main signature is supplied first and is opened dead center to create a type of pocket into which the print products to be inserted can be placed by the following feeding devices.
The timing of the conveyor drive is synchronized with a following processing machine in the conveying direction, for example a perfect binder or a gathering and wire-stitching machine, by using an electric motor, for which the timing is synchronized with the following processing machine, or by a mechanical connection to the central drive of the following processing machine. The feeding devices are driven individually, in groups, or centrally. The drives for the feeding devices and the conveyor drive are synchronized so that the supplied print products are deposited at the correct location on the material stacks. Depending on the type of drive used for the feeding devices, this can be achieved with the aid of a mechanical connection or a drive control if a motor is used.
The known apparatuses have the disadvantage that the drives for the feeding devices and the conveyor drive are rigidly connected. As a result, the accumulated error of a pusher relative to the sheet feeder increases with increasing distance to the conveyor drive, owing to dividing errors on the conveyor. Since the traction means for the conveyor is generally embodied as a chain, the tolerances continuously increase due to chain wear. Also not taken into consideration are deformations in the drive elements caused by the torque and the forces to be transferred, which additionally contribute to worsening the synchronizing accuracy. The operational safety consequently can be reduced when processing standard-size print products of the same format on longer gathering apparatuses. For example, a precise feeding of supplements to be glued onto the top sheet of a material stack, such as cards, CD/DVD-ROM, or other flat products, is not possible in this way because the relative inaccuracies between conveyor and drive are too pronounced.
It is therefore an object of the present invention to convey the last supplied print product in the conveying direction so that it is precisely aligned with the top print product on the material stack.
The above and other objects are accomplished according to the invention wherein there is provided in one exemplary embodiment an apparatus for gathering and/or assembling print products or supplements, comprising: a conveyor comprising a circulating traction mechanism, a conveying track on the traction mechanism, and uniformly spaced-apart pushers attached to the conveying track and defining respective conveying sections along the conveying track; feeding devices, each including a feed conveyor, arranged along the conveying track for supplying different print products to respective conveying sections of the conveying track; a plurality of feeding device drives each arranged to drive a respective one of the feeding devices with synchronized timing; a conveyor drive which is separate from at least one of the feeding device drives to drive the conveyor; a first measuring device arranged to detect a position of a print product conveyed on one of the conveying sections of the conveying track; a second measuring device arranged to detect a position of a different print product on one of the feed conveyors; and a control unit having computing capacity and being coupled to the first and second measuring devices to control the feeding device drives in response to outputs from the first and second measuring devices.
That is, according to an exemplary embodiment of the invention, there is provided a separate drive for the conveyor and at least one feeding device. Further, there is additionally provided a first measuring device or sensor for detecting the position of a print product transported on a conveying section of the conveying track, and a second measuring device or sensor for detecting an additional print product located on the feed conveyor. These measuring devices are connected to a control unit with computing capacity.
These and other features and advantages of the invention will be further understood from the following detailed description of the exemplary embodiments, with reference to the accompanying drawings, wherein:
The gathering and assembling apparatuses 1 shown in
The feeding devices 26 comprise feeding elements 2, which remove the print products 3 individually from existing stacks and supply these to feed conveyors 28, by which the print products 3 are deposited in a precise position on the material stacks 23 that are so formed. A person skilled in the art is familiar with the different designs for the feeders 2. The feeders 2 shown in the Figures are drum feeders, although other types of feeders may be used. The lowest print product 3 and/or the lowest supplement 33 of a stack is partially separated from the stack by suction means and is subsequently gripped by grippers arranged on the drums 32, is then conveyed away from the stack and is deposited on a feeding section 43 that is embodied as a feed conveyor 28. As shown in
Position sensors 22 for measuring the position of at least the top print product 3 on a material stack 23 and position sensors 24 for measuring the position of the print product 3 or the supplement 33 to be supplied are provided upstream of the location 36 for combining a print product 3 or a supplement 33 with the print product 3 positioned underneath. Based on the two measuring values supplied by the sensors 22, 24, the control unit 13 then computes the expected position (actual position value “a”) of print product 3 or supplement 33 to be supplied, relative to the top print product 3 of the material stack 23. As an alternative to measuring the position of the top print product 3 of a material stack 23, a position sensor 21 can be used to measure the position of the pusher 5 against which the top print product 3 of a material stack 23 rests. In this way, the variable speed drives 29 function as position-controlled slaves that are controlled by the master drive, which is the drive 7 for the conveying device 6. A system of this type is referred to as a “synchro” system. Thus, by measuring the expected effective position of a print product 3 or supplement 33 to be supplied to the top print product 3 on the material stack 23 and comparing this value to the desired position value “a,” the desired value 15 of the variable speed drive 29 can be corrected accordingly. The previously determined deviation between the actual position value “a” and the desired position value “a” can also be compensated. Geometric defects on the conveyor 6 that are caused by deformations, production tolerances, and wear are thus continuously detected and compensated, so that the print products 3 and the supplements 33 to be supplied in the conveying direction F are deposited precisely aligned with the top print product 3 of a material stack 23. The position sensors 21, 22, 24 may be positioned as close as possible upstream of the combining location 36, but at least far enough away so that a new desired value can be computed by the variable speed drive 29, even for the maximum production speed.
Shutting down the machine, of necessity, also deactivates the complete control. If manual changes are then made to the machine, the control unit 13 will not be able to detect these changes. The variable speed drives 29 can thus lose their reference, which can only be restored by conveying the print products 3 and supplements 33, as well as detecting their positions with the aid of the above-described sensors and control units 13. To avoid such an occurrence, reference cycles can be generated on the feeding devices 26 and the conveyor 6, wherein the reference cycle for the conveyor 6 can be transmitted via the signal line 20 and the reference cycle for the feeding devices 26 can be transmitted via the signal line 42 to the control unit 13. The reference cycles are respectively generated once for each machine cycle by the reference cycle sensor 40 on the conveyor 6 and the reference cycle sensors 41 for the feeding devices 26. The position in time within a machine cycle is defined by mechanical adjustments, thus making it possible to approximately synchronize the operation of the variable speed drives 29 with that of the conveyor 6, without the conveying of products 3 or supplements 33. The accuracy which can be achieved with this process corresponds to that of devices according to the prior art. The position “a” can furthermore be determined with the aid of the position sensor 22 for the material stacks and the reference cycle sensor 41 for the feeding device. Even though this mode of operation does not fully reach the possible accuracy, it nevertheless considerably surpasses that which can be reached with devices according to prior art.
It is not absolutely necessary for the print product 3 or the supplement 33 to be combined with the print product 3 on top of the material stack 23. The print product 3 or supplement 33 can be moved temporarily along on a support element 34 that is arranged above the support means 39, wherein the pushers 5 can still be used for the conveying operation, as shown in
It is furthermore conceivable to detect the position of a supplement 33 or a print product 3, relative to the print product 3 positioned underneath, by using an image recognition system, installed downstream of the combining location 36. With an image recognition system, it is possible to detect supplements 33 supplied in the conveying direction F and/or transverse thereto or at an angle thereto and to remove these when a permissible limit value is exceeded.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 05405536.3 | Sep 2005 | EP | regional |
