1. Field of the Invention
The invention relates to a device for adhesive attachment of a cover, configured for receiving a binding strip, to the flanks of a spine of a book block which is formed of bound printed sheets and transported by means of a circulating transport device, wherein the cover to be combined with a binding strip is transferred, in accordance with the cycle of the transported book block and approximately in the same direction to the book block""s transport direction, to the spine of the book block for positioning thereat and is connected with the book block during the subsequent pass through a pressing path with pressing device.
2. Description of the Related Art
It is known to provide, for the purpose of reinforcing, the spine of a book with strips of paper, textile materials or the like, a so-called binding strip, wherein the binding strips are separated from a web, which extends transversely or longitudinally to the path of back gluing processing, and are then combined with a cover being fed to the book block. Parallel glue strips are applied onto the cover during the course of feeding at a greater spacing to one another than the thickness of the book block in order to connect by means of a conveying roll, arranged downstream of the cover feeding device, the cover to the binding strip and the binding strip to the book block, i.e., to its spine provided with a glue layer, while the book block and the cover are being moved in the same direction.
It would be possible also to provide the underside of the binding strip with two spaced-apart glue strips.
The further transport of the cover connected with the binding strip is carried out by the transport device of the back gluing machine for transporting the book block where subsequently a pressing of the cover and of the binding strip onto both flanks, provided with glue, of the book block spine is carried out. For this purpose, the book block spine, which has been provided at the adjoining flanks with strips of glue, passes through a pressing station in which the cover and the laterally projecting parts of the binding strip are engaged by a parallel-moving pressing device and are pressed against the book block (disclosed in xe2x80x9cTechnologie der Klebebindungxe2x80x9d by Alfred Furler, particularly in paragraphs 8.5 and 8.6, but also well-known from the back gluing machine of the Muller Martini Bookbinding Systems).
From the time of feeding the cover up to the point of pressing the cover and the binding strip onto the book block, there is no certainty that the cover can be reliably connected via the glue strips to the binding strip, in particular, because the parts of the binding strip projecting laterally past the spine of the book block and the oppositely positioned cover have no planar surface and no means have been provided so far to secure them in their relative position to one another. This results in the condition that the cover and the binding strip on the transfer path into the pressing station with the pressing device can be moved relative to the book block.
It is an object of the present invention to provide a method and a device for the adhesive attachment of a cover provided with a binding strip onto an book block by which method and device the reliability of a precise connection of the cover with the book block is ensured.
In accordance with the present invention, this is achieved in that at least one of the lateral parts of the binding strip projecting laterally past the book block spine are loaded on the side facing away from the cover by a pressing element.
In this connection, a mechanical device, for example, a holding-down device, can provide a beneficial and simple pressing means.
One embodiment of a device for performing the method according to the invention comprises a cover conveying device and a binding strip conveying device positioned alongside a transport device for the book block and having arranged downstream thereof a pressing device acting on the cover, wherein the device is characterized in that the cover conveying device and the binding strip conveying device have correlated therewith a pressing element in the form of a compressed air supply device or an adjustable holding-down device acting on the lateral parts of the binding strip projecting laterally past the book block.
Preferably, the pressing element acting on the lateral projecting parts of the binding strip can be realized by compressed air.
Expediently, the compressed air can be supplied in a controlled fashion, i.e., can be switched on and off and/or can be adjusted with respect to amount and speed, i.e., can be adjusted to the respective conditions.
For reinforcing the adhesion between the cover, the binding strip, and the book block spine, the cover can be provided on the transfer path into the pressing station with two parallel strip-shaped glue applications having a larger spacing than the thickness of the book block.
Advantageously, the compressed air supply device directed onto the binding strip parts is arranged oppositely to at least one conveying roll supporting the cover so that a counterpressure is built up which forces the respective parts against one another.
Expediently, the compressed air supply device is connected with a compressed air source and can be controlled or adjusted with respect to the supplied amount of air and/or the speed of the compressed air.
Advantageously, the compressed air supply device is arranged so as to be adjustable in accordance to the thickness of the book block to be processed and is thus adaptable correspondingly.
The method according to the invention can be used preferably in connection with a back gluing machine or the like for the manufacture of books.