Patent Description:
A carbon dioxide laser can be used to make dark markings such as data matrices and barcodes on cardboard. When performing the transference of the marks care should be taken because a right amount of optical power should be delivered to the cardboard in order to avoid burning but still ensuring a clearly readable marks. However, this kind of careful marking to the surface of cardboard requires several process stages. Additionally, the present marking possibilities do not respond properly to the desired variety of the markings.

The present invention seeks to provide an improvement in the markings.

If one or more of the embodiments is considered not to fall under the scope of the independent claims, such an embodiment is or such embodiments are still useful for understanding features of the invention.

The articles "a" and "an" give a general sense of entities, structures, components, compositions, operations, functions, connections or the like in this document. Note also that singular terms may include pluralities.

Furthermore, words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may also contain features/structures that have not been specifically mentioned. All combinations of the embodiments are considered possible if their combination does not lead to structural or logical contradiction.

The term "about" means that quantities or any numeric values are not exact and typically need not be exact. The reason may be tolerance, resolution, measurement error, rounding off or the like, or a fact that the feature of the solution in this document only requires that the quantity or numeric value is approximately that large. A certain tolerance is always included in real life quantities and numeric values.

It should be noted that while Figures illustrate various embodiments, they are simplified diagrams that only show some structures and/or functional entities. The connections shown in the Figures may refer to logical or physical connections. It is apparent to a person skilled in the art that the described apparatus may also comprise other functions and structures than those described in Figures and text. It should be appreciated that details of some functions, structures, and the signalling used for measurement and/or controlling are irrelevant to the actual invention. Therefore, they need not be discussed in more detail here.

<FIG> illustrates an example of a marking apparatus. The marking apparatus comprises at least one carbon dioxide laser <NUM>, which output a laser beam <NUM>, and at least one laser beam directing apparatus <NUM>, which directs the laser beam <NUM> to a marking area <NUM>. From this on the at least one laser beam directing apparatus <NUM> is called the laser beam directing apparatus <NUM>, for simplicity. The marking area <NUM> is for a solid material <NUM> of vegetable fibers with natural hue. The solid material <NUM> of vegetable fibers may be cardboard or paper which is unbleached or only partially bleached having more or less the natural hue. When the solid material <NUM> of vegetable fibers is at least partly inside or fully within the marking area <NUM> a representation <NUM> of at least one mark of the one or more marks, information on which is in one or more memories <NUM>, can be formed, in the following manner, on the solid material <NUM> of vegetable fibers. The representation <NUM> is an image of the at least one mark.

At least one controller <NUM> receives information on the at least one mark from the one or more memories <NUM>. From this on the at least one controller <NUM> is called the controller <NUM>, for simplicity. Then the controller <NUM> controls the laser beam directing apparatus <NUM> and/or the at least one carbon dioxide laser <NUM> based on the information on the at least one mark to perform a selection of an energy-per-unit-area range from a first energy range and a second energy range. The selection may vary as a function of time during a single process stage from start to finish. The first energy range and the second energy range may be predetermined ranges, which are known because they depend on the material of the solid material <NUM> of vegetable fibers. The selection is based on the at least one mark each requiring at least one energy-per-unit-area range. Energy of the laser beam <NUM> per surface area of the solid material of the vegetable fibers <NUM> may be based on control parameters of the laser <NUM> and/or the laser beam directing apparatus <NUM> such as travelling speed of the laser beam <NUM>, power and frequency of pulsation of the laser <NUM> (the laser may also output the optical radiation continuously). Energy of the laser beam <NUM> per surface area of the solid material of the vegetable fibers <NUM> may be based on hatching distance and their angle with respect to representation <NUM> or a sub-feature of the representation <NUM>.

The first energy range for the laser beam <NUM> causes the solid material <NUM> of vegetable fibers to become visibly darker than the natural hue in response to interaction with the laser beam <NUM> and the second energy range causes the solid material <NUM> of vegetable fibers to become visibly lighter than the natural hue in response to interaction with the laser beam <NUM>. That is, the change to visibly darker or lighter hue takes place at an area hit by the laser beam <NUM> and it is caused by the laser beam <NUM>. The change to visibly darker can be considered to mean that a ratio of the visible light reflected from the solid material <NUM> of vegetable fibers with respect to the visible light directed to it becomes lower. Correspondingly, the change to visibly lighter can be considered to mean that a ratio of the visible light reflected from the solid material <NUM> of vegetable fibers with respect to the visible light directed to it becomes higher. It can be considered that brightness of the surface of the solid material of vegetable fibers <NUM> changes.

The laser beam directing apparatus <NUM> causes the laser beam <NUM> to travel over the solid material <NUM> of vegetable fibers in response to the control by the controller <NUM>. The travelling of the laser beam <NUM> is based on the at least one mark for forming the representation <NUM> of said at least one mark on a surface of the solid material <NUM> of vegetable fibers with the selected at least one energy-per-unit-area range in the single process stage from start to finish.

A process cycle can be defined as a single process phase or stage that completes a single manufacturing operation, from start to finish, meaning that a product passes through the single stage of its production. In this document the single stage of production includes formation of visible marks on the solid material <NUM> made of vegetable fibers of natural hue.

The single process stage can be understood to mean that once the program, which causes the at least one desired mark that is to be transferred to the solid material of vegetable fibers <NUM>, is triggered to start, it continues without a break till the end of the program and all of the at least one desired mark is replicated on the solid material of vegetable fibers <NUM> in a continuous manner.

It may be considered that the natural hue is caused by lignin without limiting to this. The vegetable fibers may comprise only virgin fibers, only recycled fibers or their combination. The vegetable fibers may comprise only wood fibers, only fibers from at least one other plant or their combination. The natural hue means that the fibers are not bleached or they are not fully bleached. Bleaching is typically performed chemically. That the fibers are not fully bleached may mean that all the fibers have been in a process causing bleaching but the process has only lightened the brownish color of the natural hue but not fully removed it. That is, a substantial part of the natural hue has remained. Alternatively or additionally, the natural hue may mean that a part of the fibers, which means less than all fibers, have been partially or fully bleached while another part of the fibers have not been bleached at all and they have the full natural hue. That the representation <NUM> is visible means that the representation <NUM> is seen with a naked eye of a human being in illumination of visible light. According to a general concept, the visible light means one or more optical bands of electromagnetic radiation within a range from about <NUM> to about <NUM>.

The wavelength of the carbon dioxide laser <NUM> may be about <NUM><NUM> ± about <NUM><NUM>. In an embodiment, the controller <NUM> may control the wavelength of the laser <NUM> with respect to the natural hue and/or composition of the solid material <NUM> of vegetable fibers. Additionally or alternatively, the controller <NUM> may control the wavelength of the laser <NUM> with respect to at least one mark that is to be transferred on a surface of the solid material <NUM> of vegetable fibers.

In an embodiment, the laser beam <NUM> may be made to travel over the solid material <NUM> of vegetable fibers by moving the laser <NUM> with respect to the solid material <NUM> of vegetable fibers. The laser <NUM> may be moved by an actuator, which may comprise electric, pneumatic or hydraulic motors, for example.

In an embodiment, the laser beam <NUM> may be made to travel over the solid material <NUM> of vegetable fibers by moving the solid material <NUM> of vegetable fibers with respect to the laser <NUM>. The solid material <NUM> of vegetable fibers may be moved by an actuator, which may comprise electric, pneumatic or hydraulic mover(s)/motor(s), conveyor belt, for example. In an example, the actuator may be a roll-to-roll system. A person skilled in the art is familiar with these kinds of movement arrangements, per se.

In an embodiment an example of which is illustrated in <FIG>, the laser beam directing apparatus <NUM> may comprise at least one laser beam deflector <NUM>. From this on the at least one laser beam deflector <NUM> is called the laser beam deflector <NUM>, for simplicity. The carbon dioxide laser <NUM> may direct the laser beam <NUM> to the laser beam deflector <NUM>, which deflects the laser beam <NUM> to a marking area <NUM> which is meant to have the solid material <NUM> of vegetable fibers with natural hue for forming the representation <NUM> of the at least one mark of the one or more marks thereon.

The controller <NUM> may then control the laser beam deflector <NUM> and/or the carbon dioxide laser <NUM> based on the information on the at least one mark to perform the selection of an energy-per-unit-area range from the first energy range for a laser beam <NUM> and the second energy range.

The laser beam deflector <NUM> may cause the laser beam <NUM> to travel over the solid material <NUM> of vegetable fibers in response to the control by the controller <NUM>. The laser beam deflector <NUM> makes the laser beam <NUM> to travel on the surface of the solid material of vegetable fibers <NUM> in order to replicate the at least one mark as the representation <NUM> to the surface.

The laser beam deflector <NUM> may comprise a first direction reflector <NUM> and a second direction reflector <NUM> which may rotate by turning with respect to their rotation axes. The first direction X and the second direction Y may be orthogonal and they can be parallel to unit vectors of a Cartesian coordinate system. The reflectors <NUM> and <NUM> may comprise silicon, molybdenum, nickel copper alloy (NiCu), aluminum and/or copper mirrors, for example, without limiting to these. The reflectors <NUM>, <NUM> may covered with gold or silver, for example. The first direction reflector <NUM> receives the laser beam <NUM> and deflects it in the first direction toward the second direction reflector <NUM> that then deflects the laser beam <NUM> in the second direction and directs the laser beam <NUM> toward the marking area <NUM> where the solid material <NUM> of vegetable fibers is. When the first and second reflector <NUM>, <NUM> rotate round their rotational axes <NUM> and <NUM> they cause the laser beam <NUM> to travel over the solid material <NUM> of the vegetable fibers according to and following a geometrical shape defined the at least one mark, the geometrical shape resulting in the representation <NUM> on the solid material <NUM> of the vegetable fibers.

The first and second reflectors <NUM>, <NUM> may be rotated round their rotation axes using actuators <NUM>, <NUM>. The actuators <NUM>, <NUM>, in turn, may comprise electric, pneumatic or hydraulic motors, for example.

Additionally or alternatively, the laser beam deflector <NUM> may comprise an acousto-optic modulator and/or magneto-optic modulator for making the laser beam <NUM> to travel on the surface of the solid material of vegetable fibers <NUM> in order to replicate the at least one mark as the representation to the surface.

In an embodiment examples of which are illustrated in <FIG>, <FIG>, <FIG>, the mark comprises information on one or more graphical patterns, one or more alphanumerical signs and/or writing symbols of the representation <NUM>. In <FIG> and <FIG> examples of representations <NUM> of a data matrix are presented. In <FIG>, <FIG>, <FIG>, the natural hue is shown with hatched lines, white area is bleached visibly lighter than that of the natural hue by the laser beam <NUM>, and the black area is made visibly darker than that of the natural hue by the laser beam <NUM>.

In an embodiment, the controller <NUM> may control the carbon dioxide laser <NUM> and/or the laser beam directing apparatus <NUM> to direct the laser beam <NUM> within an energy range about <NUM> J/cm<NUM> and about <NUM> J/cm<NUM>, without limiting to these values. Here the energy range may refer to a fixed energy range or an average energy range. The energy of the laser beam <NUM> at the surface of the solid material <NUM> of vegetable fibers depends in general on both a travelling speed of the laser beam <NUM> caused by the laser beam directing apparatus <NUM> and the optical power of the laser beam <NUM>. Additionally, the energy range or values may depend on the type or quality of the solid material <NUM> of the vegetable fibers.

In an embodiment an example of which is illustrated in <FIG> and <FIG>, only the second energy range, which causes the solid material <NUM> of vegetable fibers to become visibly lighter than the natural hue, may be selected for forming the representation <NUM> defined by a combination of areas, where one area has the natural hue and another area is visibly lighter than the natural hue.

In an embodiment, illustrated in <FIG>, the background <NUM>, which is at least the size of the one or more graphical patterns, one or more alphanumerical signs and/or writing symbols of the representation <NUM>, has been made visibly lighter that the natural hue, and the graphical data matrix <NUM> is presented with the natural hue on the background <NUM>. That is, the laser beam <NUM> has interacted with the solid material <NUM> of the vegetable fibers only in the area of the background <NUM>.

In an embodiment, illustrated in <FIG>, the laser beam <NUM> has been directed to only an area of the one or more graphical patterns, one or more alphanumerical signs and/or writing symbols of the representation <NUM>, which is a data matrix in <FIG>.

In an embodiment, illustrated in <FIG> and <FIG>, the controller <NUM> may control the carbon dioxide laser <NUM> and/or the laser beam directing apparatus <NUM> to direct the laser beam <NUM> of the second energy range within an energy range about <NUM> J/cm<NUM> and about <NUM> J/cm<NUM>, without limiting to these values, in order to cause the solid material <NUM> of the vegetable fibers to become visibly lighter than the natural hue of the solid material <NUM> of the vegetable fibers (see <FIG>, <FIG>, <FIG>). Here the energy range may refer to a fixed energy range or an average energy range. Additionally, the energy range or values may depend on the type or quality of the solid material <NUM> of the vegetable fibers.

In an embodiment, illustrated in <FIG> and <FIG>, the controller <NUM> is configured to select only the first energy range for forming the representation <NUM> defined by a combination of areas, one having the natural hue and another being visibly darker than the natural hue.

In an embodiment of <FIG>, the laser beam <NUM> has been directed to only an area of the one or more graphical patterns, one or more alphanumerical signs and/or writing symbols of the representation <NUM>, which is a data matrix in <FIG>.

In an embodiment of <FIG>, the laser beam <NUM> has been directed to only an area of the background of the representation <NUM>, and the area of the one or more graphical patterns, one or more alphanumerical signs and/or writing symbols of the representation <NUM> is left to have the natural hue. That is, the data matrix has the natural hue in <FIG>.

In an embodiment, the controller <NUM> may control the carbon dioxide laser <NUM> and/or the laser beam directing apparatus <NUM> to direct a laser beam of the first energy range within an energy range about <NUM> J/cm<NUM> and about <NUM> J/cm<NUM>, without limiting to these values, in order to cause the solid material <NUM> of the vegetable fibers to become darker than the natural hue of the solid material <NUM> of the vegetable fibers (see <FIG>, <FIG>, <FIG> and <FIG>). Here the energy range may refer to a fixed energy range or an average energy range. Additionally, the energy range or values may depend on the type or quality of the solid material <NUM> of the vegetable fibers.

In an embodiment, the optical power of the carbon dioxide laser <NUM> may be constant or controllably varying and the controller <NUM> may control the travelling speed of the laser beam <NUM> for performing the selection from the first energy range and the second energy range. In order to cause the solid material <NUM> of the vegetable fibers to become visibly lighter than the natural hue, the travelling speed of the laser beam <NUM> should be greater than the travelling speed for making the solid material <NUM> of the vegetable fibers visibly darker than the natural hue.

In an embodiment, the solid material <NUM> of vegetable fibers may move and the laser beam directing apparatus <NUM> may cause the laser beam <NUM> to travel over the moving solid material <NUM> of vegetable fibers in response to the control by the controller <NUM> based on the at least one mark and information on the movement of the solid material <NUM> of vegetable fibers. That is, the marking of the solid material <NUM> of vegetable fibers may be performed on the fly. The solid material <NUM> of vegetable fibers may move at a constant speed and the controller <NUM> may have the information of the constant speed which enables the controller <NUM> to regulate the speed of the laser beam <NUM> suitably with respect to the speed of the solid material <NUM> of vegetable fibers.

In an embodiment, the controller <NUM> may control also the speed of the solid material <NUM> of vegetable fibers and the speed of the solid material <NUM> of vegetable fibers may be constant or variable. As the information of the speed of the solid material <NUM> of vegetable fibers is available to the controller <NUM>, it may regulate the speed of the laser beam <NUM> suitably with respect to the speed of the solid material <NUM> of vegetable fibers. In this manner, it is possible to move the laser beam at a desired or constant speed with respect to the solid material <NUM> of vegetable fibers in any direction on the surface of the solid material <NUM> of vegetable fibers. That means that the movement of the laser beam with respect to the solid material <NUM> of vegetable fibers can be kept the same in a direction parallel to the movement of the solid material <NUM> of vegetable fibers and in the direction vertical to it and in any direction therebetween. A person skilled in the art is familiar with this kind of speed control, per se.

In an embodiment, the controller <NUM> may receive the information on the speed of the solid material <NUM> of vegetable fibers from an external source, and based on the received information the controller <NUM> may regulate the speed of the laser beam <NUM> suitably with respect to the speed of the solid material <NUM> of vegetable fibers. As already mentioned, a person skilled in the art is familiar with this kind of regulation of speed, per se.

In an embodiment, the controller <NUM> may set the first and/or second energy range for the laser beam <NUM> based on the properties and/or composition of the solid material <NUM> of vegetable fibers, for example. When the properties and/or composition of the solid material <NUM> of vegetable fibers changes, the controller <NUM> may also increase or decrease energy of the first and/or second energy ranges. Properties may be, for example, natural hue and/or humidity of the solid material <NUM> of vegetable fibers without limiting to these. Here the energy range may refer to a fixed energy range or an average energy range.

The marking apparatus comprises at least one optical arrangement <NUM> for forming the laser beam <NUM>. From this on the at least one optical arrangement <NUM> is called the optical arrangement <NUM>, for simplicity. In an embodiment, the carbon dioxide laser <NUM> comprises the optical arrangement <NUM>. In an embodiment, the optical arrangement <NUM> is related to the resonator cavity of the carbon dioxide laser <NUM>.

In an embodiment, the energy per unit area of the laser beam <NUM> may be increased by making a diameter of the laser beam <NUM> smaller by causing convergence to the laser beam <NUM>. Alternatively, the energy per unit area of the laser beam <NUM> may be decreased by making a diameter of the laser beam <NUM> larger by causing divergence to the laser beam <NUM>.

In addition to the optical components integrated within or with the carbon dioxide laser <NUM>, the at least one optical arrangement <NUM> of the marking apparatus may have additional and separate optical components for manipulating the laser beam <NUM>.

In an embodiment an example of which is illustrated in <FIG>, the solid material <NUM> of vegetable fibers may move and the laser beam directing apparatus <NUM> may receive information on the moving solid material <NUM> of vegetable fibers. The controller <NUM> may control, in response to the information on the movement of the solid material <NUM> of vegetable fibers, the carbon dioxide laser <NUM> to output the laser beam <NUM> with suitable energy-per-unit-area range. That is, the marking of the solid material <NUM> of vegetable fibers may be performed on the fly. The solid material <NUM> of vegetable fibers may move at a constant speed and the controller <NUM> may have the information of the constant speed which enables the controller <NUM> to regulate the carbon dioxide laser <NUM>. In this manner, the laser beam <NUM> does not need to be optically deflected although it may also be deflected. By controlling the energy-per-unit-area range as a function of time it is possible to transfer lines of various lengths and darkness onto the solid material <NUM> of vegetable fibers. The laser energy per unit area should thus be controlled, and the carbon dioxide laser <NUM> may be switched on and off for transferring lines on the surface of the solid material <NUM> of vegetable fibers. With deflection also other figures than lines parallel to the movement of the solid material <NUM> of vegetable fibers may be transferred onto the solid material <NUM> of vegetable fibers.

As illustrated in <FIG>, the controller <NUM> may control at least one optical arrangement <NUM> which comprises at least one optical component of the optical arrangement that may cause divergence and/or convergence. The at least one optical component may comprise at least one lens that forms a real image and/or at least one lens that forms a virtual image. The diameter of the laser beam <NUM> may be altered by one of the presented manner or by a combination of the presented manners.

In an embodiment, the marking apparatus may comprise a user interface <NUM>, and the controller <NUM> may present information on advancement of the formation of the representation <NUM> on the surface of the solid material <NUM> of vegetable fibers. A representation may be divided into a plurality of sub-features which may be letters of alphabets or writing character such as kanji-signs, hiragana signs, katakana-signs, Arab, Korean, (Indian) devanagari, Burmese writing symbols, or numbers, any of their combination or the like, for example. Alternatively or additionally, the sub-features may be geometrical figures such as lines, curves or polygons, any of their combination or the like, for example. When the controller <NUM> has the information how many sub-features are to be formed, the monitoring of the advancement may be based on a comparison how many of the sub-features have already been formed and how many still needs to be formed on the surface of the surface of the solid material <NUM> of vegetable fibers.

In an embodiment, the monitoring of the advancement may be based on time used for formation of a representation. The controller <NUM> may have predetermined information on a duration how long it takes to transfer a sub-feature or a whole representation to the surface of the surface of the solid material <NUM> of vegetable fibers. When a marking is on-going the controller <NUM> may monitor the time used for the formation of the representation. The percentage of used time for the formation or the representation with respect to the predetermined information may be a suitable measure of the advancement.

In an embodiment an example of which is illustrated in <FIG>, the controller <NUM> comprises one or more processors <NUM>. The one or more memories <NUM> includes a computer program code. The one or more memories <NUM> and the computer program code may, with the one or more processors <NUM>, cause the controller <NUM> to control the laser beam directing apparatus <NUM> and/or the carbon dioxide laser <NUM> to perform the selection of the energy-per-unit-area range from the first energy range and the second energy range based on the at least one mark.

The one or more memories <NUM> and the computer program code may, with the one or more processors <NUM>, cause the controller <NUM> to cause the laser beam directing apparatus <NUM> to cause the laser beam <NUM> to travel over the solid material <NUM> of vegetable fibers based on geometry of the at least one mark.

It is possible to mark one side, any side, all sides or some sides of the solid material <NUM> of the vegetable fibers. That may be done without moving the laser <NUM> and/or the solid material <NUM> of the vegetable fibers when the laser beam deflector <NUM> is utilized.

<FIG> illustrates an example of a marking method. The method steps may be performed in the following order. However, the order may also be different. In step <NUM>, at least one controller <NUM> receives information on the at least one mark from one or more memories <NUM>.

In step <NUM>, a laser beam <NUM> is output by at least one carbon dioxide laser <NUM>.

In step <NUM>, the laser beam <NUM> is directed, by a laser beam directing apparatus <NUM>, to a marking area <NUM> which is configured to have solid material <NUM> of vegetable fibers with natural hue for forming a representation <NUM> of at least one mark of the one or more marks thereon.

In step <NUM>, the at least one controller <NUM> controls the laser beam directing apparatus <NUM> based on the information on the at least one mark and/or the at least one carbon dioxide laser <NUM> to perform a selection of an energy-per-unit-area range from a first energy range for a laser beam <NUM> that is configured to cause the solid material <NUM> of vegetable fibers to become visibly darker than the natural hue in response to interaction with the laser beam <NUM> and a second energy range that is configured to cause the solid material <NUM> of vegetable fibers to become visibly lighter than the natural hue in response to interaction with the laser beam <NUM>. The selection is based on the at least one mark each requiring at least one energy-per-unit-area range.

In step <NUM>, the laser beam directing apparatus <NUM> causes the laser beam <NUM> to travel over the solid material <NUM> of vegetable fibers in response to the control by the at least one controller <NUM> based on the at least one mark for forming the representation <NUM> of the at least one mark on a surface of the solid material <NUM> of vegetable fibers based on the travelling of the laser beam <NUM> with the selected at least one energy-per-unit-area range over the solid material <NUM> of vegetable fibers in a single process stage from start to finish.

The marking method shown in <FIG> may be implemented as a logic circuit solution or computer program. The computer program may be placed on a computer program distribution means for the distribution thereof. The computer program distribution means is readable by a data processing device, and it encodes the computer program commands, carries out the measurements and optionally controls the processes on the basis of the measurements.

The marking apparatus may comprise without going to basic prior art details which the person skilled in the art is familiar with optical galvanometer(s), servo motor(s), step motor(s), rotating polygon mirror(s) (mirror(s), see <FIG>), beam expander(s), focusing optic(s), dynamic Z-axis control etc..

The software for the marking method may contain CAD (Computer Aided Design) features that make it a tool for designing marking templates for different purposes. In addition to basic shapes, marking can contain bitmap graphics, vector graphics, texts, barcodes and 2D-codes. The software may driven by a PC (Personal Computer) that controls the marking apparatus. That is, the at least one controller <NUM> shown in <FIG> may be at least partly in the PC. Alternatively, the software may be driven directly in the at least one controller <NUM> that is integrated with the laser <NUM>. Thus, the PC, per se, may not be necessary.

The marks and the control parameters of the at least one laser <NUM> may be stored in the at least one memory <NUM>.

The computer program may be distributed using a distribution medium which may be any medium readable by the at least one controller. The medium may be a program storage medium, a memory, a software distribution package, or a compressed software package. In some cases, the distribution may be performed using at least one of the following: a near field communication signal, a short distance signal, and a telecommunications signal.

Claim 1:
A marking apparatus, comprising
one or more memories (<NUM>) including information on one or more marks,
at least one carbon dioxide laser (<NUM>), which is configured to output a laser beam (<NUM>),
at least one optical arrangement (<NUM>) for focusing the laser beam (<NUM>),
at least one laser beam directing apparatus (<NUM>), the marking apparatus being characterized in that the at least one laser beam directing apparatus (<NUM>) is configured to direct the laser beam (<NUM>) to a marking area (<NUM>) which is configured to have a solid material (<NUM>) of vegetable fibers with natural hue for forming a representation (<NUM>) of the at least one mark of the one or more marks thereon, and that the marking apparatus further comprises
at least one controller (<NUM>) configured to receive information on the at least one mark from the one or more memories (<NUM>), control the at least one laser beam directing apparatus (<NUM>), the at least one optical arrangement (<NUM>) and/or the at least one carbon dioxide laser (<NUM>) based on the information on the at least one mark to perform a selection of an energy-per-unit-area range from a first energy range for a laser beam (<NUM>) that is configured to cause the solid material (<NUM>) of vegetable fibers to become visibly darker than the natural hue in response to interaction with the laser beam (<NUM>) and a second energy range that is configured to cause the solid material (<NUM>) of vegetable fibers to become visibly lighter than the natural hue in response to interaction with the laser beam (<NUM>), the selection being based on the at least one mark each requiring at least one energy-per-unit-area range; and
the at least one laser beam directing apparatus (<NUM>) is configured to enable the laser beam (<NUM>) to travel over the solid material (<NUM>) of vegetable fibers in response to the control by the at least one controller (<NUM>) based on the at least one mark for forming the representation (<NUM>) of the at least one mark on a surface of the solid material (<NUM>) of vegetable fibers with the selected at least one energy-per-unit-area range in a single process stage from start to finish.