175562-BT

Process and device for continuous treatment of a web substrate

The present invention is related to a process and a device system for continuous treatment of a web substrate, according to the preamble of the claims.

For use in printing processes special prepared paper rolls are ordered from the paper mills to be delivered only in complete rolls. In consequence huge quantities of different papers are on stock in printing offices in case special requirements should be requested on or in the printing substrates.

According to prior art coating systems are mostly used for unprinted rolls or in processes before conventional printing by an off-set printing process or today as well for the digital printing technology such as to color the paper or to make papers ready for the laser printing technology. The printing process itself is not involved in the coating treatment. This is a remarkable disadvantage for the finished printing output as the print, e.g. with toner, itself is not covered or treated in the later use.

The increased requirements of today for printed products, including its printings with off-set colors, toner or ink produced by the digital printing technologies, request the same final quality of the product in all process conditions during its dynamic production of finishing as well as in the routine for stop and go, e.g. for cleaning the printers. Furthermore new features are requested as to ensuring the requested quality by using different coating fluids such as water, emulsions, enamels, ink or glue as well as including different security elements. The same quality of the final print product must be secured for the complete substrate as well in its further use in the market. A requested final finished printed product according to new requirements as well as future jobs which request on-demand deliveries also are required for books, loose leaves, forms and so on as well. As such the substrate may be paper, textiles, parchments, plastic films and mixtures of any kind as well as for example metal with or without coatings. Higher requirements also are requested from the market with the level of quality for security printing including the requirements for resisting aging, anticounterfighting including long life printed products, such as requested by the medical industry for pharmacy products as well as from the chemistry industry. Also requested for printed products with coatings being thermo sensible is the possibility of allowing any other technology used or even to overprint the final product a second time with any digital printer.

The above mentioned requirements are satisfied with the process and the device according to the present invention as defined by the features stated in the claims.

One object of the present invention is to make the printing process part of the later treatment as a consecutive operation. During the printing process for the finishing devices the productivity of the system is improved with the present invention by having controlled parameters within defined tolerances. These parameters would cause troubles in case they should drift out of the tolerances for temperature, humidity and static loading.

With the present invention an on-line process after the printing technologies is fully controlled by a computer driven sensor system to detect e.g. a possible increased temperature and/or a reduced humidity in the substrate and thereby to stop the process until the device proves acceptable tolerances for these parameters according to what is requested for the final product after the coating treatment. The process should then be regulated and the changed process parameters on the incoming side of the device as well as within the device should be corrected in all which may have influence on the substrate or in the substrate, including prints on the substrates.

The only figure of the drawing discloses a schematic vertical section through one embodiment of a device system according to the present invention.

The drawing discloses a surface finishing device comprising a control device 1 for controlling process parameters such as the feeding tension of the substrate in the substrate path. The control device 1 is activated and driven by a sensor system 2 continuously measuring the temperature and relative humidity on a substrate 8 upon entering the finishing device.

The control device 1 also ensures that the substrate feeding also provides necessary substrate buffers for the following conditioning of the substrate 8. Also ensured is that the speed of the process is related to and kept within accepted tolerances as to measured values of humidity as well as the temperature of the substrate 8 along the process path.

The substrate 8 is tempered, normally cooled, to a desired operation temperature in a cooling system 3 into which the buffer system to produce the controlled substrate path and tension is integrated. The cooling system 3 may comprise air cooling aggregates as one possibility to regulate the temperature of the substrate 8 within accepted tolerances. Upon leaving the cooling system 3 the substrate 8 is entered into a coating device

4 comprising sets of roller trains for surface treatment of the substrate 8 from both sides. The coating device may have four units to implement for example humidity into the substrate 8 and/or coating materials on to the substrate 8 surface. Depending on the conditions this operation may be performed in two phases with one fluid or in sequence of one fluid in the first phase to the front as well as the rear side of the substrate 8, such as water in the first and for example emulsions in the second phase on the front as well as the rear face of the substrate 8.

The coating device 4 comprises an auto feeding system 6 ensuring that the substrate 8 is transported correctly through the components in the transport system of the

aggregates for treatment of the substrate 8. The disclosed embodiment comprises four aggregate units. The automated substrate feeding system 6 is so designed that loading of the device is easy done by the operator. It works with the requested substrate tension and it is regulated with the adjusted substrate speed. The whole device is independent from external signals to control the speed during loading and production.

A sensor system 5 comprising a number of sensors is arranged in the coating device 4 for measuring relative humidity and temperature of the substrate 8 at several point of the process path. Said sensor system 5 reacts on situations where such values may be outside the tolerances set. A computer stores the main programs to drive the system and to allow with the remote control concept detecting and calculating the real consume of components during the process time.

The computer is communicating with the relevant counters within the unit. The program and the interface of that computer is designed in its capacity that additional treatment devices, optical devices or mechanical devices e.g. label placement aggregates, perforation units, ink-jet heads or gluing devices can be as well controlled by this processor, even these units are attached behind this device after the output of the substrate 8 or any other places within the described process of treatment. Protocols are saved on the dynamic regulated process parameters as measured and corrected by the sensor system. Said protocol system can also ensure that new orders may be manufactured with exact the same parameters as previous printed products with same conditions, if requested, as well as on demand digital printings.

The treatment process directly in sequence after the printing process has the advantage that the printing is part of the treatment of the substrate and improves the finishing quality, visible as well as invisible, of the final printing product.

The process parameters are adjustable as static parameters, but as well they can be regulated during the dynamic process of printing to get the requested quality for the final finished printed product such as books, loose leaves and forms and so on with the features such as requested. According to the present invention higher requirements from the market including these from the security printing, long life of printed products even so for the medical, the pharmacy and the chemistry industry can be satisfied as controlled processes are secured.

It is possible to implicate fluid materials plain or partial on or in the substrate 8 or paper after printing coatings which are thermo sensible or have to be written by any other technologies even so a second time by digital printers.

The parameters are temperature, humidity, static loading as well as the adjusted parameters responsible for the thickness of the coating as well as the thickness and the volume of the paper, type of paper depending on the implicated fluid together with the speed of the paper, the pressure of the rolls and its turnings as static parameters.

Tolerances between the limits will be regulated. Tolerances outside the limits indicated give relevant signals to stop the production of the system. The relevant information is computerized and delivered to the administration desk.

All job related adjusted and fixed process parameters are documented and transferred to the data archive to be recalled on demand or in case of any reprints to adjust the equipment for the same produced quality as before. Protocols of the controlled process can be printed after the job was terminated.

With the aspects of the invention the on-line production of the printing output placed after the printers, all the following processes e.g. the cutting and the folding of the paper, have huge advantages with the controlled production conditions.

The process of on-line coatings has all relevant elements of function, which are necessary for the final finishing of the printing output to get the best quality on the requested level. Even so there is a prevention of the production of dust in the whole line, resulting from the handling of the paper by the mechanical devices during its transport. The sensor system is monitoring temperature, speed, humidity, thickness of the coating as the dynamic parameters and roller speed, respectively the roller pressure as the static adjusted parameters is so designed that the process sequence in the device system can be fixed as necessary for the best results.

The integrated computer system with the operator panel 7 stores all process parameters and data as well as the environment conditions. These are connected to the time of measurement in which the job of production was running. It is designed to respect the values of experience resulting from the tolerances of climate conditions, if after the statistic values as stored in the protocols, the manually corrected adjustments may give better results. In normal use the system works without corrections completely automated. The process of coating and other treatments can have additional elements of function with further roller systems which allow further mechanical operations e.g. punching wholes or making perforations even so only for segments and part of the printed forms. Also gluing devices and label placement aggregates can be placed in the surface finishing system. Visible or invisible ink jet devices may produce additional security features, if requested point by point.