LU87956A1 - CONTROL SYSTEM FOR POSITIONING SPECIFIED MARKINGS ON FILM COATINGS WHEN USED IN AUTOMATIC MANUFACTURING PROCESSES - Google Patents

Description

CONTROL SYSTEM FOR POSITIONING SPECIFIED MARKINGS ON FILM COATINGS WHEN USED IN AUTOMATIC MANUFACTURING PROCESSES

The invention relates to a control system for positioning predetermined markings on film webs when they are used in automatic production processes, in particular on cigarette paper webs in automatic-machine cigarette production by means of a system with a separation mechanism for separating the cigarettes from an automatically produced cigarette rod to a predetermined length. at least one paper drive roller and at least one paper deflection roller, which are arranged in this order upstream of the said separation mechanism.

The invention relates generally to the application defined in the title statement. However, in order to simplify the following description for the sake of simplicity, it should, as expressed in the preamble, be described with regard to its use in automatic cigarette manufacture, with the specific advantages which result for this particular application.

For the purpose of informing the consumer, the legislator makes the requirement to state the so-called "smoke value" (nicotine content of the sucked-in cigarette smoke) on the cigarette pack, with the tendency to set the permissible maximum values ever lower.

The best known measure to reduce the smoke value is to provide a filter (filter cigarettes). Here, the filter effect can be further enhanced by the fact that the cigarette paper, in particular in the filter area, is made with a predetermined porosity, as a result of which a predetermined proportion of fresh air is mixed in with the cigarette smoke when it is sucked in (“ventilation”). If necessary, the smoke value can be reduced again by:

Fine perforations are applied to the mouth end of the cigarette, in the case of filter cigarettes in the filter area, which further increases ventilation.

The aforementioned perforation can e.g. mechanically attached, using electrical spark discharge, or - by far the most accurate method - using a laser beam.

While the regulation of ventilation in filter cigarettes can be realized in a simple manner by a suitable choice of the porosity of the filter envelope, predetermined ventilation in filter-free cigarettes, which are still popular, can be achieved in a simple manner only via perforations in the mouth end area of the cigarettes, since the effect of Paper porosity also decreases even as the remaining cigarette length decreases.

However, in order to avoid larger variations in the ventilation effect of these perforations, which of course cannot be used to guarantee the specified smoke values, it is absolutely essential to place the perforation zones within narrow tolerances in relation to the mouth end. This is of course possible if the (preferred) laser perforation is carried out at the end of the production process, e.g. on the cigarette just cut off from the cigarette rod. Laser devices for attaching a perforation zone at this stage of cigarette manufacture are known, but are extremely expensive due to their complexity.

The most economical solution for laser perforation is, of course, to carry out the latter directly at the cigarette paper manufacturer, since this has the advantage of throughput of optimally large quantities of paper in parallel with the relatively simple laser processing of flat paper webs.

This economically optimal solution of the perforation zone production, however, has so far failed due to the lack of a process principle for synchronizing the position of the perforation zone with the separating device.

The reasons for the length changes mentioned are well known to the person skilled in the art and need not be explained in detail. They are essentially: changes in length due to aging in general, temperature humidity.

The cigarette paper is subject to tensile forces during production or when it is wound onto the bobbin, which unevenly change the distance between the ventilation zones. With longer storage, further problems arise, e.g. the effect that the tension is shifted from the inside to the outside and the paper load increases with the size of the reel.

the tensile forces acting on the cigarette paper during cigarette production are not constant over time, i.e. the paper is not always stretched uniformly as it passes through the machine, but undergoes a change in length which is dependent on many factors which cannot be determined individually.

In short, attaching a perforation zone (or attaching any other marking to the paper web, such as the cigarette label print, which must also be within narrow tolerances with respect to the mouth end of a filterless cigarette) directly from the paper manufacturer is practically not feasible according to the prior art .

In order to close this fundamental gap in the state of the art, the invention provides a control system for changing the length of the paper which is integrated in the cigarette manufacturing process.

Such a control system, which works as a supplement to a conventional cigarette production machine, must therefore be able to compensate for the fluctuations in paper elongation caused by production and production technology by generating an additional paper tension. This system essentially requires speed, stability and reliability: it must be designed in such a way that it can react quickly enough to changes in the position of the ventilation zone, is able to apply sufficient traction to the cigarette paper and, if possible, malfunctions - such as the tearing of the cigarette paper as a result of excessive tensile forces - avoids. This last requirement in particular is not easy to implement, since paper can be elastically and plastically deformed by tensile stress, but the relative changes in length that can be achieved in this way are clearly below 1%. It is therefore very complex to use this effect technically.

The object of the invention is achieved by the features stated in the characterizing part of the main claim. Further essential features of the invention emerge from the characteristics of the subclaims.

An embodiment of the invention is shown in the drawings and is described in more detail below. Show it:

FIG. 1, a cigarette with a perforation zone with stamp imprint and, for the sake of illustration, a length of 70 mm;

FIG. 2 shows a schematic illustration of the paper flow in cigarette manufacture with control components according to the invention;

FIG. 3 shows a block diagram to explain the control system structure;

Figure 4 is a structural diagram of the control loop.

FIG. 1 shows a (for the sake of illustration) 70 mm long cigarette 5 with a ventilation zone 6, the perforations of which are shown as straight-line slots 8 for the sake of simplicity (these slots in reality represent a series of fine perforations). In the example shown, the cigarette is also provided with a stamp (the cigarette brand imprint) which is within the scope of the present

Invention could function as "marking" just as easily as ventilation zone 6 or any other marking that can be detected with a sensor. The distance from the mouth end 10 of the cigarette 5 to the beginning of the ventilation zone is specified in this example as 14 mm with a tolerance of +/- 1.5 mm.

In FIG. 2 there are 12 paper bobbins delivered by the cigarette paper manufacturer with a marking (hereinafter a perforation zone 6 is to be understood to simplify the description) with cigarette paper 14, 16 a braking paper deflection roller, 17 a first paper drive roller, 18 a sensor, here as a "scanner" provided, for optical detection of the position of the perforation zones, some perforation zones in the area of the sensor 18 being symbolized with short transverse lines 20 on the paper web 14 for the sake of simplicity and the scanner emitting a first control signal when they are detected, 22 a counter assigned to the separation mechanism (cutter head 21) to deliver a machine-clock-synchronous second control signal 24, 26, an electric motor operating in generator mode, preferably a DC motor, which, on the basis of a signal 28 output by a control circuit (not shown here) for processing signals 22 and 24, processes the decelerable paper deflection roller 16 to pos ition correction of the perforation zone 20 with a predetermined braking torque. Furthermore, this figure shows a number of further paper feed and deflection rollers and the like, which, however, do not play a fundamental role in the context of the invention and are therefore not described in more detail here.

Since the paper web 14 must have a certain tension in the production system shown schematically in FIG. 2 in order to ensure a perfect paper flow, that is to say it is stretched, the distances 21 of the perforation zones 20 on the paper bobbin 12 supplied by the cigarette paper manufacturer are slightly smaller than the intended one Cigarette length (e.g. 70 mm) held. The fine adjustment of the distances 21 with the cigarette length predetermined by the working rhythm of the cutter head 21 (for example 70 mm) is carried out according to the invention with the aid of the signals 22, 24 and 28 with the generation of an additional paper tension between the drive roller 17 and the deflection roller 16 by means of the brake motor 26 .

The principle of operation of the control system required for this is shown in FIG. 3, in which the control sequence is also entered textually.

In order to meet the requirements to be placed on such a system already mentioned above, the invention provides the control circuit shown in FIG. 4 on the basis of a microprocessor-controlled controller, called DIGIREG, which, as tests have shown, meets the requirements mentioned.

The structure and functionality of this DIGIREG controller are described in detail in the thesis, Technical Regulation Technology, by Mr. Thomas Bruckmann, University of Applied Sciences Rhineland-Palatinate, Trier Department, Electrical Engineering Department, March 1991.

A DC motor from the company BBC, D-Heidelberg of the type UGTMEM-06 SB2 has proven itself as the brake motor 26 in the experiments mentioned.

The scanner from Weitmann & Konrad, D-Leinfelden-Echterdingen was used. Its light source illuminates the passing paper perpendicular to the paper plane from one side, while a photocell on the other side of the paper web transmits to the scanner the slight change in brightness that is caused by a laser-perforated zone when the scanning point is reached.

So that a control device of the type described above is practical, it must finally recognize whether the desired positioning of the

Ventilation zones (or the like) could be realized in the production process or this could make it impossible for the actual zone distances to deviate too much from the target distances on the delivered paper reel. In the latter case, the control system must be able to eliminate the defective cigarettes. This condition is also fully met by the DIGIREG microprocessor system, as has been confirmed in the experiments mentioned.

Claims (7)

1. Control system for positioning predetermined markings on film webs when they are used in automatic manufacturing processes, in particular on film webs in the automatic-machine production of piece goods with a predetermined length by means of a system with a separating mechanism (21) for separating the piece goods from an automatically produced piece goods to said length, at least one film drive (17) - and at least one film guide roller (16), which are arranged in this order upstream from said separation mechanism (21), characterized by a between said guide roller (16) and said drive roller (17 ) arranged sensor (18) for detecting said markings (20) and for emitting a first control signal (22), by means of a pulse generator (22) assigned to the separating mechanism (21) for emitting a second control signal (24), by means of a sensor Deflection roller (16) acting Bremsa unit (26), by a control circuit (40) for processing the two control signals (22, 24) and for subsequent activation of the brake unit (26) in function of a comparison of the two signals (22, 24). 2. Control system according to claim 1, characterized in that the brake unit (26) is an electric motor working in generator operation. 3. Control system according to claim 2, characterized in that the electric motor is a direct current motor. 4. Control system according to claims 2 or 3, characterized in that the core of the control circuit (40) is a microprocessor. 5. Control system according to claim 4, characterized in that the microprocessor control is carried out using a DIGIREG (42) - microprocessor control system. 6. Control system according to claim 1, characterized in that the sensor (18) is an optical sensor. 7. control system mach any of claims 1 to 6, characterized in that said piece goods are cigarettes (5) and said piece of goods is a cigarette rod.