| US4915025A | 1990-04-10 | |||
| SE457704B | 1989-01-23 | |||
| GB2215274A | 1989-09-20 | |||
| CH563877A5 | 1975-07-15 |
| 1. | A process for the manufacture of double var¬ nished carton packing blanks from sheets of carton which have been printed in a printing machine and supplied with a coat of varnish, which sheets are carried stack wise to a varnishing unit for the application of a further coat of varnish, and subsequentl carried to a punching machine for punching of the blanks, c h a r a e t e r i z e d i n that, the feeding of the sheets from the varnishing unit to the punching machine is carried out continuously, while the the successively dispatched sheets are carried through a drying or curing zone for successive and direct feeding into the punching machine. |
| 2. | An installation for the manufacture of carton packing blanks by means of the process according to claim 1, comprising one or preferably several sheet printing machines with means for applying a coat of varnish to the printed sheets, equipment for applying an extra coat of varnish to the printed sheets, and one or several punching machines for punching blanks from the sheets, including double varnished sheets, c h a r a c t e i z e d i n that the equipment for applying an extra coat of varnish is placed in direct operational rel tionshi to the puncing machine, respec¬ tively to at least one of several punching machines in use in order that sheets delivered successively from this equipment is carried to successive and direc feeding into the particular punching machine, preferably via a continuously activated drying or curing zone. |
| 3. | A punching machine for use in an installation according to claim 2, c h a r a c t e r i z e d i that it is connected to a preceding varnishing unit with a feeder for carton sheets from stacks which have been brought to the feeder while there is an interposed drying or curing zone for the sheets successively car¬ ried from the varnishing unit. |
| 4. | A punching machine according to claim 3, c h a c t r i z e i n that t. is adapted for operation even when the varnishing unit and drying/cur¬ ing zone arc not J π use. |
The present invention concerns a produc ion system for carton packing blanks consisting of sheet printing machines, equipment for varnishing the surface of the printed sheets, and a number of punching machines for the punching of blanks from the sheets. It is usual to provide the multi-colour machines with a varnishing unit which supplies the printed face of the sheet with a clear varnish, whereby the blanks are provided with a desirable surface gloss, but the extra or separate varnishing unit mentioned is desirable because it may be necessary to perform a post-processing operation on a part of the sheets i order to obtain a particularly good surface gloss. This is a more costly process, but the result is noli_:eably better, because the sheets are already "primed" with the first coat of varnish.
It has been tried to put the post-varnishing unit in direct series with a printing machine but the result is not particularly good because the surface to be varnished, even when using intermediate heating, is not perfectly dry or cured before the application of the extra varnish, and it is therefore usually the case that use is marie of the separate varnishing unit mentioned which is undoubtedly more expensive but which will provide a better quality product, because those sheets that, have to be post-processed are able to dry properly, e.g. by waiting until the next day. Generally only a minor part of the production has to be extra varnished, and using the separate varnishing unit it is a further advantage that this unit may receive sheets from any of the printing machines in use; these will quite often be supplied with a differing number of printing units, and if a post-varnishing unit is to be used it should of course be fitted to a machine i h the highest number of
printing units which may then give a reduction in capa¬ city when it is a print with less colours that is to be post-varnished. By using a separate varnishing unit alJ the printing machines may be used optimally.
On the other hand there is a clear operative separ¬ ation between three different types of units in the system, i.e. the printing machines, the post-varnishing machines, and the punching machines, and to each of these units there belongs the necessary supply equipment for the sheets, a so-called feeder, and internal trans¬ ports of stacks of sheets between the units have to be performed. An advantage of using a post-varnishing unit on one or equally well on several of the printing machi¬ nes is in fact that this unit may work "on-line", i.e. without the use of a feed.r for sheets supplied in a stack.
The present invention aims at a simplification of the compl te system without the ocσurence of the disad¬ vantages mentioned as to a reduction in the quality of post-varn shing.
According to the invention the separate post-var¬ nishing unit is arranged in direct operative combination with one of the punching machines used in the system, i.e. before it, in order that the sheets from stacks of sheets are fed successively into the post-varnishing unit and are continuously carried to the punching mach¬ ine whithout this in itself being supplied with a feeder for single sheets from the appropriate stacks of sheets.
The punching machines work indenpendently of whether the printing is with more or less colours which means that it is not criticalt which punching machine the post-varn shing unit is put in conjunction with. Because the print and the first coat of varnish may be thoroughly dried when the stacks of sheets are brought to the feeder of the combined post-varnishi g and punch¬ ing machine there is a good certainty that post-varnish¬ ing may be performed with a high qua ity, and the only
problem that remains is that also the punching machi ha_ certain requirements fer the degree of dryness o r curing of the surface layer of the sheets, because this layer may be locally damaged by pressure devices which fix the sheets during punching. This requirement for dryness or curing is however less rigorous than the corresponding requirement before application of the extra layer of varnish, and the reqiremeπt may be much easier fulfilled by using a suitable intermediate heat¬ ing or other curing in between Lhe application of the further layer of varnish and the following punching of the carton blanks. The desirable direct, transfer of the sheets from the post.-varnishing unit to the punching machine may occur through a reasonably short drying or curing section, whereby it becomes completely feasible to combine the post-var ishing unit with the punching marhinc, i .e. in particular with one of several punching machines in the system, all according to the need for post-processing of the sheets produced.
By means of the invention the printing machines may be used optimally while at the same time no separate loading of stacks of post-processed, high quality sheets to the punching machines is required.
The invention is schematically illustrated on the drawing in which
Kig. 1 is a diagram of a traditional printing out i ,
Fig. 2 is a corresponding diagram of a an outfit or a system according to the invention, and
Fig. 3 is a side view of a combined post-varnish ng and punching unit according !o the invention.
In Fig. 1 it is shown that a number of printing machines 2 in a printing shop are each supplied with a varnishing uni 4 and that there are furthermore a number of punching machines 6 with corresponding feeder 8 Ln which may be brouglit stacks of printed sheets from any of the printing machines 2.
I has been indicated that a single printing mach¬ ine may be .supplied with an extra varnishing unit. 10, but as mentioned this may for several reasons be less appropriate, a d it is normally prferred to use a sep ¬ arate varnishing unit 12 with feeder 14 which may re¬ ceive stacks of sheets for post-processing from any of the printing machines, while the print and the first coat of varnish may be properly dried or cured before the application of the extra coat of varnish.
The punching machines 6 may receive stacks of sheets from both any of the printing machines 2 and from the varnishing unit 12 which is indicated by different connective lines. Correspondingly this will mean that the sheets in the different stacks may be properly dried before the punching, so that the sheets may be handled without, damaging the printed and varnished surface. It has been realized that specifica ly the the drying or curing of the extra coat of varnish mentioned may occur so quickly that it is possible to connect, the extra varnishing unit 12 to one of the punching machines 6 when there is provided between these units a suitable drying or curing zone 16 which is successively passed bv the post-varnished sheets, see Fig. 2. The sheets in those stacks that come from the printing machines 2 may still be thoroughly dried when they are brought to the varnishing unit 12, e.g. the day after the printing, because they may then be dried "in depth", and not only on the printed surface but also in the material below it, so that optimal conditions for a good result of the post-varnishing are created. By the drying or curing of the extra coat of varnish it is only this particular coat that has to cure, i.e. a quite thin surface layer which is not partially penetrated into a lower porous layer, and just because of this it is possible by means of a reasonabl short drying or curing zone 12 to obtain a quite sufficient fixing for the subsequent manipula-
tion of the sheets in the punching machine without damaging the surface of the sheets.
The length or power capacity of the drying zone 16 should be adjusted such that the punching machine 6 is able to work at. full operational speed with sheets, the extra coat of varnish of which has dried or cured suf ¬ ficiently after the treatment in the varnishing unit 12.
In Fig. 3 a practical embodiment of the combined varnishing and punching machine 12,6 has been indicated. The corresponding feeding uni 14 is shown at right in the figure, and it will be understood that in the system according tot he invention it is possible to avoid a separate feeder for the puncher 6, and that it is avoi¬ ded to carry stacks of sheets to the punching machine from the separate varnishing unit 12 shown in Fig. 1.
Nothing prevent.s the same punching machine 6 from being used for handling sheets that need not be supplied with an extra coat of varnish, whereby it is omitted to activate the varnishing unit 12 and the drying zone 16, i.e. the sheets are allowed to pass from the feeder to t.he punching machine without invervening processing. Hence the punching machine is not dedicated to handling double varnished sheets only, i.e. it is quite useful also in periods where the production of this type of sheet is not relevant.
In case a particular printer's shop has an extra large production of double varnished sheets it may be appropriate that the combination shown in Fig. 3 is used for more than Just on punching machine.