WO2023118615A1

WO2023118615A1 - Automatic and dynamic traceability device for tissue paper rolls

Info

Publication number: WO2023118615A1
Application number: PCT/ES2021/070911
Authority: WO
Inventors: Francisco Javier HUERTOS IZQUIERDO; Xabier ANGULO VINUESA
Original assignee: Lortek S.Coop.
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2023-06-29

Abstract

Device for automatic and dynamic traceability of tissue paper rolls, insertable into a tissue paper production line comprising a paper machine (1) and a converting machine (2). The device comprises: an item of marking equipment (5), for making a marking on the paper roll (3) leaving the paper machine (1); an item of display equipment (6), for automatically reading the marking generated by the marking equipment (5) on the paper roll (3) prior to its entry into the converting machine (2); and an external controller element (7), linked to the display equipment (6) and also to the paper (1) and converting (2) machines. The external controller (7) comprises an item of computer equipment for receiving and processing the readings collected by the display equipment (6) and for synchronizing the processes of the paper (1) and converting (2) machines.

Description

AUTOMATIC AND DYNAMIC TRACEABILITY DEVICE FOR TISSUE PAPER ROLLS

DESCRIPTION

Object of the invention

The present invention falls within the technical field of accessories for paper machines, as well as in that of devices for analyzing materials characterized by the use of optical means, more specifically in that of those configured to analyze mobile material. like paper during its manufacturing process.

The invention relates in particular to a device for automatic and dynamic traceability of reels of tissue paper, which uses combined techniques of laser marking and artificial vision.

Background of the invention

In the initial phase of papermaking, the cellulose fibers are mixed with water to form a paste. This mixture is introduced into the head of a paper machine, which is in charge of gradually removing the water from the initial paste. The end result is a huge sheet of paper, which is rolled into large reels weighing up to 3t. These reels produced by the paper machine are later transported to the conversion lines, where two or more layers of paper from different reels are combined, and the resulting material is cut into smaller rolls to manufacture final products such as toilet paper, kitchen paper , napkins or paper tissues.

Each reel leaving the paper machine is identified with its own code at the exit of the paper machine, so that relevant production history data can be traced. This code is generally of the numeric type and comprises up to twelve digits. However, at present, there is no known tissue paper traceability system that allows the quality of the tissue to be identified at any point along the reel. It is necessary to highlight that the paper machine works at speeds of around 2,000 m/min and that the winding is carried out at 1,500 m/min. On the other hand, the speed of the conversion lines is 600 m/min. Process conditions mean that the tension of the paper is different in both stages, thereby losing the traceability of possible existing defects (exact meter in which it has been produced) and of the quality of the paper throughout the reel.

The fact that there is no specific traceability system for the tissue paper of each reel entails a series of drawbacks, among which the following should be highlighted:

- At present, the important process data and quality parameters measured in the paper machine are only associated with the reel code, but cannot be transmitted directly to the converting lines to adapt their parameters to the quality of the paper being processed.

- The paper perforations generated in the paper machine can cause breaks somewhere in the converting line, causing unplanned stops. These shutdowns are costly in terms of time, energy, and process efficiency.

- The problems associated with the absence of a device that allows detailed monitoring of the product result in high costs for the paper company.

Likewise, due to the nature of the material and the processing, it is necessary to take additional safety precautions to avoid problems derived from the generation of smoke when acting on the paper by means of a laser.

Some devices for the traceability of paper reels are currently known, but they are focused on other types of paper, such as paper money, and cannot be transferred to the case of tissue paper. For example, US patent US2008197972 describes a security paper having a printed or attached data matrix. The data matrix includes an encoded unique identifier for the security paper that can be read by a scanner and compared to a store of unique identifiers to authenticate the banknote. The data of the Data matrix can be layered, with a second layer containing more data associated with the banknote. Data at one or more layers can be encrypted using different encryption algorithms so different parties can access data at different layers.

The PCT international application with publication number WO2011026693A1 refers to a method for marking defects in a moving web of material, in particular a web of paper, tissue or cardboard, in which the material web is monitored for relevant defects. Said defects are detected and analyzed by means of a control and analysis unit that activates a marking device that marks the presence of a defect in the material band. The marking of the band of material is carried out by means of laser light. As can be seen, in this method a marking is produced after the detection of a possible defect, and only in that case.

Application W02007122284 describes a method of providing paper or board with a non-repeatable mark after the paper has been removed from the paper machine and dried. Marking is done by focusing laser energy on the fibers of the material on the surface of an object in the form of a band, or throughout its thickness. The invention also relates to marked paper or board, which can be made by the method, or to a product obtained therefrom by further processing.

As already mentioned, the speeds of the process, together with the fragility of the material, constitute a key difficulty when developing a Traceability Device for tissue paper reels.

The existence of a specific traceability system for tissue paper reels would allow the following advantageous actions:

- A location at any point along the reel of defects produced in the paper machine, which allows action to avoid or reduce breaks in the converting lines.

- A traceability of the quality of the paper throughout the reel, giving rise to an automatic response to the characteristics of the tissue paper that is being processed. - An identification of quality in the final product.

- A repetitive process with guarantees of traceability.

- Elimination of less ergonomic and complex tasks derived from paper tears in the converting lines, with the consequent increase in productivity per operator.

- Greater connectivity between the paper machine process and the converting lines.

Therefore, there is a need for a Device for the automatic and dynamic traceability of tissue paper reels that makes it possible to overcome the aforementioned objections.

Description of the invention

The object of the invention consists of a device for automatic and dynamic traceability of tissue paper reels that allows the creation of automatic marking patterns on tissue paper rolls, and the subsequent visualization of said marking patterns.

The device can be inserted into a tissue paper production line, more specifically between a paper machine and a paper converting machine, and basically comprises the following elements:

- marking equipment, configured to mark the reel of tissue paper coming out of the paper machine, preferably on a lateral edge of the reel, without affecting the integrity of the paper, where said marking consists of a code of traceability;

- a visualization equipment, which allows an automatic reading of the traceability code generated by the marking equipment; and

- An external controlling element, linked to the visualization equipment and to the paper and converting machines.

With respect to the marking equipment, due to the special characteristics of tissue paper such as its very reduced thickness, special devices and parameters are necessary that allow such marking to be carried out without perforating or tearing the paper. In its preferred embodiment, the marking equipment comprises a high resolution CO 2 laser device and long focal length lenses. The laser device allows tissue paper to be marked without affecting the integrity of the paper. The distance between the paper web and the laser device, as well as the power of the latter, around 100W, are key parameters to avoid perforation of tissue paper.

It is necessary to consider that the high winding speeds of the paper machine, of approximately 1500 m/min, make it necessary to have equipment that allows a reduced marking time.

In turn, the laser marking device is accompanied by the aforementioned long focal length lenses, which allow very high precision marking in very small areas. This facilitates the subsequent reading of the traceability code through the vision system.

In its preferred embodiment, the marking operation using this equipment consists of laser engraving an alphanumeric code on the tissue paper band, with a repetition interval of every meter, in order to be able to associate both the quality of the paper and the possible appearance of defects at a certain position along the entire coil. Said code later allows synchronizing the processes of the paper and converting machines.

The alphanumeric code preferably consists of a binary code based on dots and lines. The marking of the code is carried out in the longitudinal direction of the paper web, on its edge. This marking zone, preferably around 20mm wide, is subsequently removed when it is cut from the tissue reel during the converting process.

The laser marking device is preferably attached to a support that guarantees correct marking in the intended area and maintenance of the optimum distance.

With respect to the visualization equipment, it is available before the entrance of the already marked tissue paper in the converting machine, and is configured to read the code embedded in the paper. For this, the equipment includes a high-speed linear camera equipped with a vision lens, lighting means and a control and synchronization module for the camera-lighting unit. Lastly, the external controller is linked to the visualization equipment and to the paper and conversion machines, and comprises a computer configured to receive and process the images collected by the visualization equipment, to subsequently associate them to a database containing the batches of tissue paper, among other relevant data.

The external controller also allows for correct synchronization of the processes of the paper and converting machines, to avoid jams, breaks, incorrect reel tensioning and other common problems. Thus, important process data and measured quality parameters are associated with the reel code, and are transmitted by the controller directly to the converting machine in order to adapt its parameters to the quality of the paper being processed.

The device allows the marking of tissue paper by means of a CO2 laser and with winding speeds of the paper machine (1500 m/min) without appreciating perforation of the paper. Subsequently, conversion speeds of 600 m/min have been simulated under laboratory conditions and a correct visualization of the marks made on tissue paper has been obtained.

Description of the drawings

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of its practical embodiment, a set of drawings is attached as an integral part of said description. where, with an illustrative and non-limiting nature, the following has been represented:

Figure 1.- Shows a schematic view of the device for automatic and dynamic traceability of reels of tissue paper inserted in a production line. Figure 2.- Shows a reel of tissue paper after marking an alphanumeric code on the side of the sheet.

Preferred embodiment of the invention

A detailed explanation of a preferred embodiment of the object of the present invention is provided below, with the help of the aforementioned figures.

The described automatic and dynamic traceability device for tissue paper reels can be inserted into a tissue paper production line, more specifically between a paper machine (1) and a paper roll conversion machine (2) (3). ) tissue from the paper machine (1). The production line also includes tension rollers (4) arranged between the paper machine (1) and the converting machine (2) to modify the tension and circulation speed of the paper roll (3) between both machines (1, 2).

The device allows the creation of an automatic marking pattern on the paper roll (3) coming from said paper machine (1), and the subsequent visualization of said marking patterns, prior to their entry into the converting machine (2). .

To do this, the device includes a marking unit (5), configured to carry out a marking on the roll of paper (3) coming out of the paper machine (1), a display unit (6), which allows automatic reading of the marking generated by the marking system (5) on the paper roll (3), and an external controller element (7), linked to the display equipment (6) and to the paper (1) and conversion (2) machines , as schematically illustrated in Figure 1.

The marking equipment (5) comprises a laser marking device and long focal length lenses. In this preferred embodiment, the laser marking device is of the high-resolution CO2 type and is attached to a support that guarantees correct marking in the intended area of the paper roll (3) and maintenance of the optimum distance to prevent damage. . Said distance between the marking device and the paper roll (3) is 150 mm in the embodiment shown here. It is described.

Despite the fact that said marking distance is configured to prevent damage to the paper roll (3), it is contemplated that the traceability device incorporates elements for the extraction of smoke.

As can be seen in figure 2, the marking equipment (5) generates a marking on a longitudinal edge of the paper roll (3), which is later read by the display equipment (6) and eliminated in the conversion machine. (2). In this preferred embodiment, the marking consists of an alphanumeric code, more specifically a binary code based on points and lines.

Regarding the display equipment (6), it is arranged before the entry of the paper roll (3), already marked by the marking equipment (5), in the conversion machine (2), and is configured to perform a reading of the code inserted in the paper. The visualization equipment (6) comprises a high-speed linear camera (8) equipped with a vision lens, lighting means (9) and a control and synchronization module for the camera (8)-lighting means (9) assembly. ).

In this preferred embodiment, the visualization of the marking is carried out at 200 mm from the roll of paper (3).

Finally, the external controller (7) is linked to the display equipment (6) and to the paper (1) and conversion (2) machines, and comprises a computer configured to receive and process the images collected by the display equipment. (6), to later associate them to a database where the batches of rolls of tissue paper (3) are recorded, among other relevant data.

The external controller (7) also allows a correct synchronization of the paper machine (1) and conversion (2) processes, to avoid jams, breaks, incorrect tensioning of the paper roll (3) and other common problems.

Claims

9 CLAIMS

1. Automatic and dynamic traceability device for tissue paper reels, insertable in a tissue paper production line comprising:

- a paper machine (1) for generating a roll of tissue paper (3);

- a converting machine (2) for converting the roll of paper (3) into a final product; and

- tension rollers (4) arranged between both machines (1, 2); the device being characterized in that it comprises:

- marking equipment (5), configured to carry out marking on the roll of paper (3) coming out of the paper machine (1);

- a display unit (6), configured for automatic reading of the marking generated by the marking system (5) on the paper roll (3) prior to its entry into the conversion machine (2); and

- an external controller element (7), linked to the display equipment (6) and to the paper (1) and conversion (2) machines; where the external controller (7) comprises computer equipment for receiving and processing the readings collected by the display equipment (6) and for synchronizing the processes of the paper machines (1) and conversion (2).

Traceability device according to claim 1, wherein the marking equipment (5) comprises a laser marking device and long focal length lenses.

3. Traceability device according to claim 2, wherein the laser marking device is of the high resolution CO2 type.

Traceability device according to any of the claims 2-3, wherein the marking equipment (5) comprises a support for the laser marking device.

5. Traceability device according to any of the previous claims, where the visualization equipment (6) comprises a high-speed linear camera (8) equipped with a vision lens, lighting means (9) and a control and synchronization module of the camera (8)-illumination means (9) assembly.

Traceability device according to any of the claims 2-5, wherein the distance between the marking device and the paper roll (3) is 150 mm.

7. Traceability device according to any of the preceding claims, wherein the display equipment (6) performs a display of the marking at 200 mm from the paper roll (3).

8. Traceability device according to any of the preceding claims, wherein the device incorporates elements for smoke extraction.