Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-05-07
2001-01-09
Gray, Linda L. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S254000, C156S257000, C156S267000, C156S268000, C156S345420, C427S428010
Reexamination Certificate
active
06171430
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for offset varnishing, which is particularly suitable for use in the manufacture of paper and cardboard articles, and to a product for the application of the method and to a printing machine equipped to carry out the method.
BACKGROUND OF THE INVENTION
In the printing industry, in the manufacture of paper and cardboard articles, and in similar areas of application, it is frequently necessary to provide protective varnishing of a printed medium such as cardboard or the like. The varnishing constitutes the final stage of the printing process and consists in the application of a layer of protective varnish which covers the whole surface of the printed and varnished material on or off the production line.
At the present time, indirect varnishing is carried out in the following way: a template which may be made of various types of material, such as linoleum or equivalent material, suitably coated with adhesive, is affixed to a plate designed to be applied to a rotating cylinder. The template reproduces the pattern of the areas of the medium to be varnished. For example, in the case of the production of cut-outs to form boxes, the template will have a perimeter corresponding to that of the cut-out product. The plate is then applied to the plate-cylinder. During the rotation of the plate-cylinder, the outer surface of the template is continuously in contact with the varnish. The collected varnish is transferred to the surface of a blanket cylinder. The blanket cylinder then transfers the varnish deposited on its surface directly to the medium to be processed, the transfer taking place with the aid of an opposing impression cylinder.
This method has numerous disadvantages. One of the disadvantages being that materials of the linoleum type are opaque, insufficiently soft, and consequently hard to cut.
In offset printing machines, production line printing and varnishing systems are used, with machines printing five or more colours and a coating stack with which the complete or reserved varnish is applied. For the varnishing of areas, materials of the rubber-coated fabric type (blankets) are normally used for direct varnishing. The coating is removed from the material in those areas where varnishing is not required. This system is complicated and expensive, particularly owing to the cost of the material and of the coat-removal operations. Furthermore, the rubber-coated material is opaque, and consequently the transfer of the varnish to the medium is not always optimal.
SUMMARY AND OBJECTS OF THE PRESENT INVENTION
The object of the invention is an offset varnishing method which is simpler and more economical than the conventional methods, while maintaining a high quality of the finished product.
A further object of the invention is a product which is particularly suitable for the application of this method.
A further object of the invention is a varnishing assembly to carry out the method according to the invention.
Basically, the method according to the invention is characterised in that a laminated material consisting of two connected layers is used for the production of the template. The upper layer of the material is cut along the pattern of the template which is to be formed, while the lower layer is kept whole. The portions of said upper layer which are not to be varnished are detached from the lower layer and the laminated material is applied to a press means capable of interacting with an opposing cylinder. The upper layer of the laminated material collecting the varnish from distribution means and applying the varnish to the medium to be varnished.
According to this method, therefore, a laminated material, from which the template to be applied to the cylinder of the varnishing assembly is formed, is used for direct varnishing, thus avoiding the operations of removing the coating of the blanket. The same product may also be applied in indirect varnishing systems. In this case, the laminated material replaces the metal plate to be applied to the plate-cylinder.
The operations for the formation of the template are greatly simplified. A further simplification is achieved by specifying the use of a transparent laminated material, which enables the upper layer of the material to be cut simply by laying the material by contact on a form reproducing the pattern of the template to be formed.
Advantageous characteristics of the laminated material according to the invention are stated in the attached claims.
The invention will be understood more clearly by examining the description and the attached drawing, which provides a practical and non-restrictive illustration of the invention. In the drawing:
REFERENCES:
patent: 2243832 (1975-05-01), None
patent: 48-43285 (1973-12-01), None
patent: 60-146088 (1985-08-01), None
patent: 1-262135 (1989-10-01), None
Forner Egidio A.
Marangoni Roberto
Nassi Aldo
Gray Linda L.
McGlew and Tuttle , P.C.
Moroel di Marangoni Roberto & C. Sa.S.
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