ES2769023T3 - Apparatus for orienting magnetic flakes - Google Patents

Abstract

An apparatus for orienting magnetic flakes in a fluid carrier printed on a substrate in a printing process, the apparatus comprising: a rotating roller (610) for positioning with an outer surface close to the substrate, the rotating roller (610) comprising a cylindrical body (501) comprising a cavity (506) characterized by a magnet (509) rotatably positioned within the cavity (506) to create a magnetic field of a predetermined configuration emanating from the outer surface of the rotating roller (610) into the substrate; and means for rotating on itself (504, 505, 507, 512) the magnet (509) within the cavity during the printing process to orient the magnetic flakes in a pattern.

Description

DESCRIPTION

Apparatus for orienting magnetic flakes

Technical field

The present invention is generally related to optically variable pigments, films, devices, and images and, more specifically, to an apparatus for alignment or orientation of magnetic flakes, for example during a painting or printing process, to obtain an effect optical illusion.

Background of the Invention

Optically variable devices are used in a wide variety of applications, both decorative and practical. Optically variable devices can be manufactured in a variety of ways to achieve a variety of effects. Examples of optically variable devices include holograms printed by credit card embossing and in authentic software documentation, variable color images printed on banknotes, and that enhance the surface appearance of items such as motorcycle helmets and wheel trims .

Optically variable devices can be made as a film or sheet that is pressed, stamped, glued, or otherwise attached to an object, and can also be made using optically variable pigments. A type of optically variable pigment is commonly referred to as a variable color pigment because the apparent color of images appropriately imprinted with such pigments changes when the viewing and / or illumination angle is tilted. A common example is the “20” printed with variable color pigment in the lower right corner of a twenty dollar bill, which serves as an anti-counterfeiting device.

Some anti-counterfeiting devices are concealed, while others are intended to be seen. Unfortunately, some optically variable devices that are intended to be viewed are not widely known because the optically variable appearance of the device is not dramatic enough. For example, the color variation of an image printed with variable color pigment may not be seen under uniform fluorescent ceiling lights, but is easier to see in direct sunlight or under spot lighting. This may make it easier for a counterfeiter to place counterfeit notes without the optically variable feature because the recipient may not be aware of the optically variable feature, or because the counterfeit note may appear substantially similar to the authentic one under certain conditions.

Optically variable devices can also be made with magnetic pigments that align with a magnetic field after application of the pigment (typically contained in a carrier such as a vehicle for ink or a vehicle for paint) to a surface. However, magnetic pigment paint has been used mostly for decorative purposes. For example, the use of magnetic pigments to produce painted wheel trims having a decorative feature that appears to have a three-dimensional shape has been described. A pattern was formed on the painted product by applying a magnetic field to the product while the painting medium was still in a liquid state. The paint medium had dispersed magnetic non-spherical particles, usually called flakes, that lined up along the lines of the magnetic field. The field had two regions. The first region contained lines of magnetic force that were oriented parallel to the surface and distributed in a desired pattern shape. The second region contained lines that were not parallel to the surface of the painted product and that were distributed around the pattern. To form the pattern, permanent magnets or electromagnets with the shape corresponding to the shape of the desired pattern were placed under the painted product to orient non-spherical magnetic particles dispersed in the paint in the magnetic field while the paint was still wet. When the paint dried, the pattern was visible on the surface of the painted product when the incident light rays on the paint layer were influenced in different ways by the oriented magnetic particles.

Similarly, a process for the production of a flake magnetic particle pattern in a fluoropolymer matrix has been described. After coating a product with a composition in liquid form, a magnet with a desirable shape was placed on the underside of the substrate. The magnetic flakes dispersed in a liquid organic medium are oriented by themselves parallel to the magnetic field lines, tilting from the original flat orientation. This inclination varied from perpendicular to the surface of a substrate to the original orientation, which included flakes essentially parallel to the surface of the product. The flat oriented flakes reflected the incident light back to the observer, while the reoriented flakes did not, providing the appearance of a three-dimensional pattern in the coating.

Although these approaches describe paint-based, three-dimensional appearance imaging methods and apparatus, they are not suitable for high speed printing processes because they are essentially batch processes.

US Patent No. 3,873,975 issued to Miklos et al issued on March 25, 1975 describes a magnetic system for authentication and interrogation of security documents such as credit cards, airline tickets, etc., the which uses magnetic recording of security patterns in a recording medium that has a pattern of permanent magnetically detectable fixed information. This recording medium is prepared by providing a sheet having a non-magnetic base layer and a layer lying thereon which incorporates magnetically anisotropic magnetizable particles that temporarily have freely permitted rotation. The magnetizable particles located at selected positions in the layer are magnetically aligned to form a fixed information pattern, such as an alphanumeric character, by passing the sheet near a rotating cylinder. The cylinder has a plurality of small permanent magnets mounted on a non-magnetic outer surface of the cylinder in a pattern corresponding to the fixed information pattern and has the magnets oriented to provide substantially unidirectional magnetic fields in the layer when close to it. The cylinder is rotated as the sheet is passed close to it to apply the magnetic fields in the layer to physically align the magnetizable particles in the selected positions to implant the fixed information pattern in the layer. Stamp printed patterns form a security feature that can be magnetically read for document authentication.

The apparatus described by Miklos et al, while apparently allowing continuous magnetic printing of predetermined two-dimensional security patterns by orientation of magnetic particles on a recording medium, has certain disadvantages.

First, the Miklos device can magnetically stamp only substantially two-dimensional patterns by copying geometric arrangements of the magnets mounted on the cylinder, with each magnet essentially providing a "dot" in the pattern printed by stamping on the magnetic layer. It would be very difficult, assuming it were possible, to use this technology to provide predetermined substantially three-dimensional (3D) or complex arrangements of magnetic flakes that are necessary to provide optical images with variable or illusive optical effects, such as rolling objects and images with depth illusion. .

Second, in the Miklos et al device, the magnets are mounted on the outer surface of the cylinder, and therefore project from it. This can be very disadvantageous in contact printing, when the cylinder is in contact, possibly under certain pressure, with the sheet on which the magnetic layer is located.

Third, since the magnets in the Miklos device are fixedly attached to the surface of the cylinder, this device cannot be used to form illusory images that can be produced by magnets that rotate on themselves.

EP 1493590A1 describes a method and means for producing a magnetically induced pattern in a magnetic particle containing coating that also uses a rotating cylinder to orient magnetic particles in predetermined patterns. The device comprises a body of a permanent magnetic composite material having at least one flat or curved surface etched with the pattern corresponding to the desirable sign pattern. The magnetic material is magnetized in the direction perpendicular to the surface. Irregularities on the surface, produced with a recording, produce changes in the direction and strength of the resulting magnetic field. These changes cause a different alignment of magnetic particles in different parts of the wet ink, making it possible to form an image with a shape corresponding to the shape of the engraving. The device may be a permanently magnetized flexible plate mounted on a rotary cylinder of a printing press, the surface having etched surface irregularities in the shape of the signs located on the outer surface of the cylinder. However, the approach of Patent EP 1493590 has certain limitations. The steps necessary to produce the engravings on the permanent magnetic material can be cumbersome; Furthermore, printing with the engraved surfaces is generally aimed at reproducing the engraved signs or drawings, and is limited in terms of the optical effects it can produce. For example, the inventors of this invention have discovered that when printed in accordance with the teachings of EP 1493590 using variable color inks, a very poor color variation effect is achieved as a result. A color variation effect has the best appearance, that is, a great color sweep and a high value of color intensity, when the particles that provide the effect are parallel or almost parallel to the surface of the substrate, which is difficult to determine. achieve using the device of patent EP 1493590.

US2004 / 051297A1 describes a method and apparatus for aligning magnetic flakes on a carrier to create optically variable images in a high speed linear printing operation, which is also useful in understanding the present invention.

Therefore, it is desirable to provide an apparatus for high-speed inline printing and painting that reorients magnetic pigment flakes into predetermined substantially 3D patterns to provide illusive and / or variable optical effects, and that does not involve the use of printing surfaces. with protruding magnets.

It is also desirable to provide a roll with the allowable twist for high speed inline printing that can be easily assembled and disassembled to form different combinations of optical images and variable or illusory optical effects.

It is another object of the present invention to provide an apparatus for continuous line printing that uses revolving magnets to orient magnetic flakes in predetermined substantially 3D patterns to provide optical images with the illusion of depth.

Summary of the Invention

In accordance with the invention, these objects are achieved by an apparatus as defined in claim 1. The dependent claims define preferred and advantageous embodiments of the invention. Optionally, the apparatus can orient magnetic flakes contained in a printed fluid carrier on a substrate in a printing process, the apparatus comprising a roller having the rotation allowed for positioning with an outer surface close to the substrate, said roller comprising one or more parts magnetized to create a magnetic field of a predetermined configuration emanating from the outer surface of the roll into the substrate to orient the magnetic flakes in a selected pattern, where the outer surface of the roll is substantially regular to provide substantially uniform contact with the substrate through the outer surface of the roller during the linear printing process.

Optionally, the rotating roller comprises a plurality of magnetized parts separated by non-magnetized or magnetized parts different from the roller to create magnetic fields of predetermined configurations emanating into the substrate to distribute the magnetic flakes on the substrate in predetermined patterns that form an illusive image and / or optical effect.

Optionally, the rotating roller comprises a cylindrical body covered by a flexible sheet of a magnetic material that is selectively magnetized to provide the magnetized portions of the roller.

In accordance with another aspect of this invention, the rotating roller comprises a cylindrical body of non-magnetic material having one or more cavities formed therein, and one or more permanent magnets located within said one or more cavities to form the one or more more magnetized parts of the roll, the one or more permanent magnets being formed to create the magnetic field of the predetermined configuration.

Optionally, the rotating roll comprises a plurality of roll sections located non-permanently next to each other to form a cylindrical roll body, each roll section comprising one or more magnetized parts to create a magnetic field of a predetermined configuration that emanates from the outer surface of the roll into the substrate to orient the magnetic flakes in a selected pattern; the outer surface of the roll is substantially regular to provide a substantially uniform contact with the substrate through the outer surface of the roll during the linear printing process; the roller sections are interchangeable to form different combinations of the magnetic flake patterns on the substrate. The magnetized parts may be formed by one or more permanent magnets located within cavities formed within the roller sections, each of the magnets being shaped to provide a predetermined configuration of the magnetic field in the substrate having magnetic flakes dispersed over he and around said substrate.

Optionally, the one or more cavities are shaped to securely hold the one or more flush permanent magnets with an outer surface of the cylindrical body.

In accordance with an embodiment of the invention, the one or more permanent magnets comprise a first magnet that is located at a lower height with respect to an outer surface of the cylindrical body of the roller.

Optionally, the one or more permanent magnets comprise a first magnet that is located with the allowed rotation inside one of the cavities, and means for causing the first magnet to rotate on itself inside the cavity during the process of printing to provide an illusion of depth to the image formed by the first magnet on the substrate in the linear printing process.

Optionally, the roller sections are mounted with the rotation allowed on the shaft with a bearing, and the apparatus further comprises first gear means for rotating the cylindrical body of the roll about the shaft, and second gear means that couple the first magnet with the shaft to make the first magnet rotate on itself about an axis normal to the outer surface of the roller when the roller is rotated about the axis.

Optionally, the cavity in which the first magnet is located with the allowed rotation extends radially forming a channel from the axis to the outer surface of the first section, the apparatus further comprising a shaft located with the allowed rotation inside the channel , the shaft having an outer end to which one of the permanent magnets is fixed, and an inner end, rotatingly engaging gear means the shaft with the shaft to make the one of the permanent magnets rotate on itself when it is it rotates the section around the axis, and a gear means to rotate the cylindrical body of the roller around the axis. Optionally, the present invention comprises an apparatus for orienting magnetic flakes on a fluid carrier printed on a substrate in a printing process, the apparatus comprising a rotating roller for positioning with an outer surface close to the substrate, said roller comprising: a cylindrical body comprising a cavity; a magnet rotatably positioned within the cavity to create a magnetic field of a predetermined configuration emanating from the outer surface of the roll into the substrate; and means for rotating the magnet on itself within the cavity during the printing process to orient the magnetic flakes in a predetermined pattern that forms an illusion of depth on the substrate.

Brief description of the drawings

The invention will be described in greater detail with reference to the accompanying drawings, which represent preferred embodiments thereof, in which:

Figure 1a is a simplified diagram showing a side view of a linear printing apparatus incorporating a magnetic roller in accordance with an embodiment of the present invention;

Figure 1b is a simplified perspective of a magnetic roller with magnetic assemblies for use in the apparatus illustrated in Figure 1a;

Figure 2a is a simplified perspective view of a magnetic roller incorporating embedded permanent magnets;

Figure 2b is a simplified perspective view of a part of the roll shown in Figure 2a with an embedded magnet having a star-shaped outer surface;

Figure 2c is a simplified side view of a magnetic assembly for printing illusory three-dimensional images in accordance with an embodiment of the present invention;

Figure 2d is a simplified side view of a magnet for printing illusory three-dimensional images in accordance with another embodiment of the present invention;

Figure 3 is a simplified perspective view of a roller having a selectively magnetized outer casing;

Figure 4a is a simplified cross section of a printed image which will be hereinafter referred to as a "flip-flop";

Figure 4b is a simplified cross section of a printed “rolling bar” image with an illusion of depth;

Figure 4c is a diagram of the magnetic field of the magnetized sheet having a two pole orientation; Figure 5a is a cross sectional side view of a roller section incorporating static magnets; Figure 5b is a perspective view of the roll section illustrated in Figure 5a;

Figure 5c is a simplified diagram showing the sectionalized roll assembly;

Figure 6a is a cross sectional side view of a roller section incorporating magnets that rotate on themselves in accordance with an embodiment of the present invention;

Figure 6b is a perspective view of the roll section illustrated in Figure 6a;

Figure 7a is a perspective view schematically illustrating a partially assembled sectionalized roll with magnets rotating on themselves;

Figure 7b is a perspective view schematically illustrating a fully assembled sectionalized roller with magnets rotating on themselves;

Figure 8a is a drawing illustrating the hemispherical axisymmetric alignment of magnetic particles dispersed in a thin layer of ink printed on a substrate;

Figure 8b is a perspective view of the same magnet that rotates on itself at three angles of rotation after the magnet has completed a single revolution about the vertical axis, with a sheet having flake-like ink applied to it located within the vault-shaped field;

Figures 8c and 8d are photographs of the hemispherically aligned impressions;

Figure 9a is a perspective view schematically illustrating a partially assembled sectionalized roll with annular magnets continuously surrounding the roll;

Figure 9b is a perspective view schematically illustrating a fully assembled body of a sectionalized roller with ring magnets continuously surrounding the roller;

FIG. 10 is a simplified diagram illustrating the printing of continuous images running the length of the substrate on a linear printing apparatus in accordance with an embodiment of the present invention using the roll shown in FIG. 8a;

Figure 11a is a simplified perspective view of a roller having permanent magnets extending across its working surface;

Figure 11b is a simplified side view of the roll shown in Figure 10a;

FIG. 12 is a simplified diagram illustrating the printing of continuous images extending through the substrate on a linear printing apparatus in accordance with an embodiment of the present invention using the roll shown in FIG. 10a;

Detailed description

Exemplary embodiments of the apparatus of the present invention for orienting magnetic flakes contained in a paint, ink, or other fluid carrier printed on a substrate in a continuous linear process will now be described, first with reference to Figures 1a-1c.

FIG. 1a is a schematic simplified side view of a part of a printing apparatus 200 in accordance with an embodiment of the present invention. An important part of the apparatus of the present invention is a magnetic roller, which in this document is understood as a roller that has magnetized parts and differently magnetized or magnetized parts. The term "magnetized parts" in relation to the roll of the present invention is used herein to refer to a permanent magnet embedded in the roll, or to a selectively magnetized area of the roll adjacent to its surface, or to an alternately shaped part of a roller having a predetermined magnetization other than the magnetization of surrounding roller areas, to form a predetermined magnetic field profile emanating from the roller. In the printing apparatus illustrated in Figure 1a, the magnetic roll of the present invention is implemented as a printing roll 210. Said printing roller 210 includes magnets 202, 204, 206, 208, which are located inside the printing roller 210, forming the magnetized parts of the distributed roller forming a pattern that correlates with a printed image 220. A substrate 212, such as a continuous sheet of paper, a plastic film, or a laminate, is moved at high speed between a pickup cylinder 214 and the printing roll 210. Pickup cylinder 214 picks up a relatively thick layer 213 of liquid paint or ink 215 from a source reservoir 216; the liquid paint or ink 215 contains platelet-type magnetic pigments, or flakes, for example as described in US Patent No. 6,808,806. The term "magnetic pigment" is used to refer to a pigment that will be aligned in a magnetic field. For the sake of discussion, the terms "printing" or "printed" will be used to describe generally the application to a surface of pigments contained in a carrier, which may include other techniques, including techniques to which other persons may refer. as "painting".

The flakes are preferably reflective and are magnetically alignable or steerable within the optically transparent ink base, hereafter referred to as the carrier, provided the ink or paint remains fluid. The flakes can also be absorbent and / or diffractive, as described for example in US Patent 6,902,807 by the same owner, and can include marker flakes and / or flakes of variable color.

The paint or ink is spread to the desired thickness on the pickup cylinder 214 with a doctor blade 218. In accordance with this invention, the ink vehicle 215 can be colorless or tinted. During the printing of an image between the pickup cylinder 214 and the printing roller 210, the substrate 212 with a layer 213 of wet ink is introduced into a magnetic field to form an illusory image. When wet ink is exposed to a magnetic or electric field, flat or magnetic or electric field-aligned particles in the pigment are aligned along magnetic field lines. In this way, the magnets located on the printing roller orient, that is, selectively align, the magnetic pigment flakes in at least part of the printed image 220. Preferably, the magnetic field of the magnetic parts, for example 206, emanating from the outer surface of the roll into the substrate 212 is shaped for a desired, desirable, or predetermined configuration to orient the magnetic flakes in a selected pattern, for example, by providing an illusory optical effect. Typically, a tensioner 222 is used to maintain the desired tension of the substrate as it is exiting the print roller 210 and pickup cylinder 214, and the image on the substrate is dried with a dryer 224. The dryer could be a heater. For example, either the ink or paint could be UV curable and harden with a UV lamp.

In another embodiment, a cylinder incorporating magnetic parts, for example magnets 202, 204, 206 and 208, to align flakes contained in a liquid carrier 212 can be used as or in place of tensioner 222, rather than as roller 202 Print. In yet another embodiment, a magnetic roller can be used as a third cylinder in apparatus 200 located between heater 224 and pickup cylinder 214.

Figure 1b shows a magnetic roller 232 that can be used in apparatus 200; it has been described in US Patent No. 7,047,883. The roller could be a pickup cylinder or a tensioner, as explained in conjunction with Figure 1a, or another roller in a printing system that makes contact with the printing substrate before ink or paint is set. Magnetic assemblies 234, 236, 238, 240, 241 are attached to the roller with screws 242, which allow the magnetic assemblies to be changed without removing the roller from the printer. The magnetic assemblies could be configured to produce 234, 236 "flip-flop" images or 238 "rolling bar" images, or they could be patterned magnetic 240, 241 material that produces a patterned image on the printed substrate, or other magnetic configuration selected. The magnetic roll structures are aligned with the sheet or roll to provide the desired magnetic field pattern to fields printed on the substrate with flakes of magnetic pigment. The illustrated patterns represent flat patterns that follow the roll circumference curve.

It is advantageous in applications to have an outer surface 244 of the roller 232 sufficiently regular or smooth, otherwise it may potentially deform or even damage the substrate 212. For these applications, it is preferred that the outer surface 244 has no protruding part, producing substantially regular and uniform contact of the roll with the substrate through the outer surface of the roll.

Accordingly, the permanent magnets are built into a cylindrical body of the roller to provide the magnetic field of a predetermined configuration required to form a desired image or optical effect; alternatively, a roll with an appropriate magnetizable surface material is selectively magnetized in predetermined patterns. In the description provided later in this document, we will describe different embodiments of rollers having magnetic parts and the substantially regular outer surface for orienting magnetic flakes in a continuous line printing process, for example, using apparatus 200. In which Following, the different configurations of permanent magnets embedded or inserted in the roller, or fixed to it, as well as the selectively magnetized parts of the roller, will generally be called the magnetized parts, or the magnetic parts, of the roller , or simply the magnetized or magnetic parts. Preferably, the outer surface of the magnetic rollers described later in this document with reference to Figures 2a-11 is substantially regular and has no protruding parts, and deviates from a better fit cylindrical surface by less than - 0.5 mm, and more preferably less than - 0.1 mm.

Magnetic rollers can be divided into two families: discrete and continuous. A discrete roll has one or more magnetic parts, for example, magnets or magnetic assemblies located adjacent to the outer surface of the roll and spaced apart from each other with non-magnetized or magnetized parts in different ways from the roll. The discrete roller is a roller that is used to shape multiple images or optical effects on the substrate in a repetitive way, for example, like a chessboard, where each individual image or part of the individual image is aligned within the margins of the Magnetic field emanating from a particular magnetic part of the roll through the outer surface of the roll and directed into the substrate, for example, as schematically illustrated in Figures 2c and 2d. A continuous roll provides uninterrupted printing, for example by producing a continuous line or stripe, on the substrate along the surface of the substrate, that is, in the direction of movement of the substrate 212 in Figure 1a, or through the substrate, by example in the direction normal to the plane of Figure 1a or at an angle to it.

A magnetic roller can be built as a unit with a solid body with attached or embedded magnets, or as a set of several identical or different roller sections with integrated magnetic systems. The convenience of the sectional magnetic roller is obvious in its flexibility: the roller with sections of a particular configuration of magnetic parts can be easily disassembled and reassembled again, including sections with different magnetic parts, to form a different combination on the substrate of images and / or optical effects.

The magnets or magnetic assemblies on a discrete roller can be left immobilized, that is, static with respect to the roller body, or they can be placed with the allowed rotation within a cavity located in the cylindrical body of the roller so that they rotate on themselves or rotate around an axis inside the body below the substrate during the printing process to provide an image with a striking illusion of depth, as described below.

Figure 2a schematically illustrates a magnetic roller 332 for orienting magnetic flakes. Magnetic roller 332 has a solid cylindrical body 301, also hereinafter referred to as cylindrical element or drum, preferably of non-magnetic material, in which they are formed, i.e. obtained by milling body 301 from its outer surface 333, a plurality of cavities. As shown by dark shaded areas of roller 332, permanent magnets of predetermined shapes, eg magnets 302 and 303, are inserted into the cavities as necessary to form the desired flake patterns, forming magnetic portions of roller 332. Figure 2a, the cavities are shown as shaded areas in dark color with the magnets, for example magnets 302, 303 and 335 inserted inside, showing a cutout in a part of the body 301 for the benefit of the observer to illustrate the positions of the magnets, for example, the cylindrical magnet 302 and the prism-shaped magnet 335, inside the drum 301. The cavities have the predetermined shape and dimensions of the permanent magnets, and the magnets are held in their interior in a static and immovable way. In some embodiments, the magnets 302, 303 can be fixed in place by adhesive, screws, clamps, etc., or can be snap-fit and held in place by traction. The permanent magnets 302, 303, while shown by way of illustration with cylindrical and rectangular shapes, have at least their outer surfaces, for example, as indicated by an arrow 335, shaped to create magnetic fields of predetermined configurations, to orient the Magnetic flakes in desired 3D patterns when the roller is used in the printing apparatus 200. In the shown embodiment, roller 332 is mounted on a shaft 304 with bearings not shown in the figure, and a sprocket 305 fixedly attached to the roller is further provided to rotate roller 332 about axis 304 during the process of Print.

In one example, the magnets 302, 303 are flush with the outer surface 333 of the body 301, such that the outer surface of the roller 332 with the magnets 302, 303 therein is substantially regular to provide substantially uniform contact with the substrate 212 through the outer surface of roller 332 during the linear printing process. The term "contact" is used herein to refer to direct or indirect contact between two surfaces, that is, through an intermediate sheet or plate. In another example, at least one of the magnets 302, 303 is located lower than the outer surface 333 of drum 301, and the recess is filled with a non-magnetic filler, for example, an epoxy resin, tin, brass , or other material, to make the outer surface of the roller substantially regular as previously described herein. The possibility of having different magnets at different distances from the ink layer is advantageous for creating different types of optical effects provided by the respective magnetic flake arrangements. Generally, to form flake arrangements that provide sharp image transitions, such as to form a "flip-flop" image, the ink-magnet distance should be minimized. However, to form images or optical effects in which image transitions should be run, for example to provide an illusion of depth as in a "rolling bar" image, the magnets are preferably placed at a greater distance from the layer of ink, for example between 3,175 mm (0.125 ”) and 19.05 mm (0.75”) for a “rolling bar” image depending on specific graphics requirements. Rolling bar images and flip-flop images, and magnet arrangements that can be used in their manufacture are described, for example, in US Patent No. 7,047,883 to the same owner.

Figure 2b is a simplified perspective section of a portion of a roll 332 'with a magnetic assembly 244 embedded in the roll. The magnetic assembly has a cross section in the shape of a star, and its surface 244 'is substantially flush with the outer surface of the roller. The magnetic assembly could be shaped permanently magnetized material, as illustrated in Figure 12F, or could have a tip section of SUPERMALLOY, MU-METAL, or a similar material, as illustrated in Figure 12E, below. The roller rotates in the direction of the first arrow 246 and a paper or film substrate 248 moves in the direction of the second arrow 250. An ink field 252 including magnetic pigment flakes has been printed on the substrate. The field was above the surface of the star-shaped magnetic array when the roller was close to the substrate, and an illusive optical star-shaped feature 254 formed in the field. In a preferred embodiment, the magnetic pigment flakes are fixed while the magnetic assembly is in contact with the substrate.

In one example, the illusive optical effect 254 is a star with an apparent depth much greater than the physical thickness of the printed field. This star can be formed, for example, with the outer surface 244 'of the magnet 244 located at a lower height with respect to the outer surface of the roller 332'.

Figure 2c is a computer simulated side view of a magnetic assembly 256 with a permanent magnet 258 that provides the magnetic field and is directed toward substrate 248 by a tip 260 patterned from SUPERMALLOY or other high permeability material. Lines 262 of the modeled magnetic field are shown for illustrative purposes only. Some "supermagnetic" materials are hard, brittle, and generally difficult to machine into intricate shapes. SUPERMALLOY is much easier to machine than, for example, NdFeB magnets, and therefore can provide an intricate magnetic field pattern with enough magnetic field strength to align the magnetic pigment flakes in the desired pattern. Also, the low remaining magnetization of SUPERMALLOY and similar alloys makes them easier to machine.

Figure 2d is a computer simulated side view of a magnetic assembly 264 with a permanent magnet 258 'shaped. The entire length of the magnet does not need to be shaped, but only the part that produces the desired field pattern in the substrate 248. Although some materials that are commonly used to form permanent magnets are difficult to machine, at least in the section of Tip simple patterns can be formed. Other materials that form permanent magnets are machinable, and can provide enough magnetic force to produce the desired illusive optical effect.

Similarly, magnet alloys can be cast or shaped into relatively complex shapes using powder metallurgy techniques.

Another example roll is illustrated in Figure 3. In accordance with this embodiment, a magnetic roll 353 is manufactured by winding a flexible sheet 502 of magnetic material with selectively magnetized parts 503 around a cylindrical element or drum 501 which is preferably made of non-magnetic material. The generally unmagnetized flexible sheet 502, apart from parts 503, is coating drum 502 and is held on its surface by a pressure sensitive adhesive. Before winding, areas 503 of sheet 502 were selectively magnetized to their full thickness to form magnetized portions of sheet 502 into predetermined shapes, shown here as exemplary dollar signs. Assembled roller 352 has a smooth uninterrupted surface formed by the outer surface of sheet 502. One sheet with a magnetization pattern can easily be replaced with another when needed. In another example, the flexible sheet of magnetizable material 502 is first magnetized uniformly in one magnetic orientation, and then part of the sheet uniformly magnetized in a predetermined shape or shapes is selectively magnetized in another magnetic orientation or orientations, so that parts 503 The magnetic rollers 352 are separated from each other by differently magnetized parts of the sheet 502.

This method of forming a magnetic roll has many advantages. The magnets formed in the sheet 502 by selective magnetization do not require carving or removing the material to modify the magnetic field. Inside the magnetic material of the sheet 502 an image 503 of an object, logo or sign is created, so that the magnet provides a field that corresponds to the object, logo or signs when the field is used to align flakes in paint or ink. Advantageously, the object, logo or sign encoded on the flexible magnetic sheet 502 by means of selective magnetization cannot be seen, but is present and generates a magnetic field that aligns within the field flakes placed on a substrate to replicate the object, logo or sign. The magnetic sheet 502 provides a naturally regular outer surface of the roller 352, without protrusions or undercuts, thereby allowing the roller 352 to be brought into close contact with the substrate 212 of the printing apparatus 200 without the risk of deforming the substrate even when apply pressure. US Patent Application No. 11 / 560,927, pending herein, provides a detailed description of different selective magnetization methods of sheet 502 to form magnetized parts of the sheet to align magnetic flakes on the patterned substrate Preset or selected providing different images and / or optical effects.

Generally, the magnetic flake pattern created on the substrate by a magnetized part or parts of the roller according to the present invention forms on the substrate an image of an object, a sign, or a logo, or adds an illusory optical effect such as an illusion of depth or movement to the image printed on the substrate with the magnetic ink. In some embodiments, the image provides a dynamic optical effect when viewed at a variable viewing angle or at a variable illumination angle. When the ink is illuminated by a light source and viewed with the naked eye or an optical instrument, platelet-like magnetic pigment particles or flakes aligned in different ways reflect incident light differently. A part of the particles is oriented with respect to the substrate, the light source and the observer in such a way that it reflects the light rays reaching it towards the observer's eye. Another part of the print particles reflects light rays in different directions because they are tilted at different angles to the direction of the observer. When the printed coated substrate is tilted with respect to the light source or the observer, the first part of the pigment particles no longer reflects light to the observer. These particles begin to reflect light in a different direction while the particles in the second part begin to reflect light rays in the direction of the observer. When particles gradually align in the ink layer, the tilting of the substrate causes an illusory motion effect to appear. When particles are aligned along the lines of a magnet that was shaped into a predetermined pattern, a part of the printed layer replicates the shape of the magnet creating a three-dimensional effect. In this region it seems as if the image comes out of the substrate towards the observer.

Examples of Printed Illusive Images

By way of example, Figures 4a, b illustrate some of the images or optical effects that can be produced using the examples described earlier in this document of the rollers with reference to Figures 1a, 2a-3. Figure 4a is a view in simplified cross section shown in US Patent No. 7,047,883 of a printed image 20 which is called a "flip-flop", and which is an example of a dynamic optical effect that can be produced by orienting suitably magnetic flakes contained in a printed fluid carrier on a substrate. The flakes are shown as short lines in the cross section view. The figures are not drawn to scale. A typical flake could be twenty microns wide and approximately one micron thick, so the figures are merely illustrative.

The flip-flop includes a first printed part 22 and a second printed part 24, separated by a transition 25. In the first part, pigment flakes 26 surrounded by a carrier 28, such as a vehicle for ink or a vehicle for paint, they have been aligned parallel to a first plane and, in the second part, flakes 26 'of pigment have been aligned parallel to a second plane; this results in a substantially 3D pattern of magnetic flakes that can be produced using appropriately shaped magnetic field emanating from the outer surface of the aforementioned magnetic rollers having magnetized parts of predetermined shapes; Examples of such magnetic structures are provided in US Patent No. 7,047,883.

Flakes generally appear shiny when viewed normal to the flake plane, while flakes they appear dark when viewed along the edge of the plane. For example, light from an illumination source 30 is reflected by the flakes in the first region towards observer 32. If the image is tilted in the direction indicated by arrow 34, the flakes in the first region 22 will be pointed. , while the light will be reflected by the flakes of the second region 24. In this way, in the first observation position the first region will appear light and the second region will appear dark, while in the second inclined observation position the fields will produce a “flip-flop” effect, the first region becoming dark and the first region becoming light. This provides a very striking visual effect. Similarly, if the pigment flakes are variable in color, one part may appear to be of a first color and the other part to another color when viewed at a first viewing or lighting angle, and such parts may appear to be they change color when viewed at a second viewing or lighting angle. The manufacturing process for diffusing flakes is described in detail in US Patent No. 6,692,830. US Patent Application No. 20030190473 describes the manufacture of chromatic diffusing flakes. The production of a chromatic diffusing flake is similar to the production of a diffusing flake, however one of the layers is required to be magnetic.

The wearer is typically transparent, colorless or tinted, and the flakes are typically quite reflective. For example, the wearer could be tinted green and the flakes could include a metallic layer, for example a thin film of aluminum, gold, nickel, platinum, or metal alloy, or they could be a metal flake, such as a flake. nickel or alloy. The light reflected by a metallic layer through the green-tinted carrier might appear bright green, while another part with pointed flakes might appear dark green or another color. If the flakes are just metallic flakes on a colorless carrier, then one part of the image might look metallic shiny, while another part might look dark. Alternatively, the metal flakes could be coated with a tinted layer, or the flakes could include an optical interference structure, such as a Fabry-Perot type absorbent-separator-reflector structure.

Figure 4b is a simplified cross section of a printed image 42 of a kinematic optical device referred to as a "rolling bar" for purposes of discussion, in accordance with another embodiment of the present invention. The image includes pigment flakes 26 surrounded by a transparent carrier 28 printed on a substrate 29. The pigment flakes are curvedly aligned, in a pattern that reproduces substantially reflective planes of a Fresnel cylindrical mirror. As with the flip-flop, the region or regions of the rolling bar that reflect light from the faces of the pigment flakes towards the observer appear clearer than areas that do not directly reflect light towards the observer, creating a impression of reflected light from a polished metal cylinder. This image provides a clear band (s) or bar (s) that appears to move, or “roll” through the image when the image is tilted with respect to the angle of observation, assuming a source (s) ) fixed lighting (s).

The bar may also appear to have depth, although it is printed on a plane. Virtual depth may appear to be much greater than the physical thickness of the printed image; This aspect of the image is called an illusory optical effect. The slant of the flakes of a selected pattern reflects light to provide the illusion of depth or "3D" as it is commonly called. A three-dimensional effect can be obtained by placing a shaped magnet or magnets for example within a cavity of the roller 332 in a position located at a lower height at a certain distance from the paper or other substrate with magnetic pigment flakes printed on the substrate contained in a carrier fluid. The flakes are aligned along magnetic field lines forming predetermined 3D patterns, thereby creating the 3D image after hardening (eg drying or curing) of the carrier. Often the image appears to move when tilted, so that cinematic 3D images can be formed.

Alternatively, a substantially 3D effect can be obtained by appropriately magnetizing a selected area or region of the magnetizable topsheet 502 overlying the roller 352, such that the magnetic field emanating from the top surface of the selectively magnetized portion would substantially reproduce the magnetic field of the appropriately shaped permanent magnet or magnets located at a lower height. By way of example, Figure 4c shows a selectively magnetized sheet 30 in which magnetized portions of the sheet are formed, which are shown by areas with high density of lines of magnetic force, such that the magnetic field emanating from Sheet 30 is substantially a magnetic field from a magnet having a bi-pole orientation in the plane of Sheet 30.

Sectional roller

Referring now to Figures 5a-c, another example provides a sectionalized magnetic roll for use in aligning magnetic flakes in predetermined patterns. The sectionalized roll 410 schematically illustrated in cross section in Figure 5c has a cylindrical body 420, also referred to herein as a cylindrical element or drum, which is assembled or shaped from a plurality of cylindrical roll sections 400, the which are removably placed next to each other to form the cylindrical body of roller 410. In Figure 5c, drum 410 is shown by way of example as formed from 3 cylindrical roller sections. Each of the sections 400 has one or more cavities for insertion of permanent magnets of predetermined shapes therein, as described above with reference to a solid roll illustrated in Figure 2a. Roller sections 400 are shaft mounted 403 as shown in Figures 4a, 4b and 4c, and are placed on said axis next to each other. Advantageously, the roller sections on the assembled roller are interchangeable, such that different combinations can be formed during printing.

Figures 5a and 5b schematically show a single roll section 400; the roller section 400 has a partially hollow body 402 having cavities within which permanent magnets 401 of predetermined shape or forms are placed and fixedly attached; cavities 401, referred to in this specification using the same reference labels as for the respective magnets located therein, are open to an outer surface 444 of roll section 400. For illustrative purposes, the magnets 401 located in the respectively shaped cavities are shown in cone shapes. In other embodiments the magnets 401 can be any appropriate shape to orient the magnetic flakes in predetermined patterns to provide the desired images or optical effects. Roller section 400 is recessed on one side to form a ring-shaped opening or recess 450 that can be used to facilitate insertion of the magnets into cavities 401. Roller section 403 has a centrally located cylindrical channel for shaft 403, which extends through final assembly 410 and on which other cylindrical sections can be mounted with allowed slip. Each of the sections 400 has a set of pins 404 and corresponding holes 405, which form next to each other a first interlocking means for interlocking the roller sections in the assembly in a fixed relative orientation to rotate together on shaft 403. Pins 404 of an individual section are inserted into corresponding holes 405 of another section by interlocking sections with each other as shown in Figure 5c, thereby providing roll integrity. In other examples, alternative locking means can be used to secure each of the roll sections by preventing their rotation relative to the others in the sectional roll assembly 410.

Second locking means are provided to lock sections 400 on shaft 403 so that they rotate together with the shaft. In the example shown, the second locking means is formed by a key 406 which is inserted into appropriately shaped grooves provided both in the cylindrical body 402 of the roller section and in the shaft 403, thereby preventing the rotation of the section 400 around axis 403. Alternatively, key 406 may be integral with section body 402 or with axis 403 projecting from either. The sectional roller enables the assembly of sections 400 with different magnetic configurations as shown in Figure 4c, in which differently shaped dark shaded areas represent permanent magnets of different shapes desired to form a particular pattern of images or magnetic optical effects induced in the magnetic layer located on the substrate 212.

The sectionalized approach described above is very useful for manufacturing a roll with a magnet that rotates on itself inside the roll about an axis that is generally normal to the outer surface of the roll, such that in the linear printing process the outer surface of the magnet is rotating on itself within the plane of the substrate 212 when the rotation of the roller brings the magnet closer to the position of the substrate, as illustrated for example by magnet 206 in Figure 1a.

In Figures 6a and 6b is shown schematically an embodiment 510 of a roller section with magnets rotating on themselves, Figure 6b providing a perspective view of the roller section 510, while Figure 6a shows the section Roller 610 in cross section. A body 501 of the cap-shaped section of the roller section 510 is located, or mounted, with the allowable rotation, on a shaft 502 using a ball bearing 503. Shaft 502 has a first 45 ° bevel gear 504 statically mounted, for example snap-fit, thereon. The section body 501 receives a rotational movement from a gear wheel 505 fixedly attached thereto and driven by a pinion not shown in the drawings. The body 501 of the section has one or more cavities 506 which extend radially in a channel from the outer surface 544 of the section 501 towards the axis 502. Inside the channel 506 is a cylindrical shaft 507. Shaft 507 is rotatably coupled to section body 501 by a ball bearing 508. A permanent magnet 509 is attached to one end of shaft 507; In what follows the 509 magnet it will be called the first magnet. In the shown embodiment, the first magnet 509 is located at a lower height with respect to an outer surface of the cylindrical body of the roller. At the other end of shaft 507 a second 45 ° bevel gear 510 is provided. Gears 510 and 504 have a matching pitch; they form engaging means, hereinafter referred to as second engaging means, for coupling the first magnet 509 with the shaft 502 to cause the first magnet to rotate on itself about an axis normal to the outer surface of the roller 610 when the roller is rotated about the axis. A sheet-shaped cover 511 covers the roller section 501 in an end roller assembly providing a smooth and regular outer surface of the sectionalized roller, as illustrated in Figures 7a and 7b. In different roll assemblies, the sheet-shaped cover 511 may have a different thickness to separate the magnets 506 from the substrate 212, depending on the strength of the magnets, the viscosity of the ink, the magnetic properties of the particles of pigment, press operating speed, and other factors. Preferably magnets 506 are located at a lower height inside body 501, such that their outer surface is separated from cover 511 by a gap. Toothed wheel 505, hereinafter referred to as the first engaging means, is used to rotate the cylindrical body of roller 610 about axis 502.

When gear 505 is actuated, it rotates section body 501 about shaft 502 that remains static; the rotational motion of the body 501 is translated by the bevel gears 504, 510 to the shafts 507, which rotate on themselves around their radially oriented axes, thereby causing the magnets 509 to rotate on themselves within the channels or cylindrical cavities 507, while simultaneously moving in a circular orbit with section 501 about an axis 502 along a planetary-type path creating a magnetic field of a desired dome-shaped configuration emanating from the outer surface of the roll, and which is directed into the substrate 212 at predetermined positions when the roll rotation brings the magnet closer to the substrate with the magnetically alignable flakes scattered on it. In another embodiment, the magnets 509 can be actuated independently of the rotation of the roller body, for example by a motor or by electric motors located for example inside the section body 501.

Figures 7a and 7b schematically illustrate a sectionalized magnetic roller 610 assembled from sections 510. Each of the roller sections has a set of pins and corresponding holes not shown in Figures 6a-7b that are similar to those described. with reference to Figures 5a and 5b. The sections 510 are assembled side by side on axis 503 to form a cylindrical body, also referred to herein as a cylindrical element, of roller 610. The assembled sections are then covered by cover 511 covering the sections for forming the magnetic roller 610 and to provide a smooth regular outer surface to the roller 610 even when the magnets 509 are located at a lower height. Figure 7a shows a partially assembled roll, while Figure 7b shows a fully assembled roll. In Figures 7a and 7b, cover 511 is shown cut away for illustrative purposes. Advantageously, self-rotating magnets can be used to form dome-shaped magnetic fields, which can be used to orient magnetic flakes in a circular pattern that forms a Fresnel reflector, thereby forming hemispherical images with an illusion of depth. , as described in commonly assigned US Patent Application No. 11 / 278,600. Figure 8a reproduced from this application illustrates an axisymmetric hemisphere-shaped alignment of magnetic particles 323 dispersed in a thin layer of ink 324 printed on a substrate 325 in a printed non-concave Fresnel mirror arrangement. Reference number 321 denotes the cross section of the field having lines 322 emanating from the magnet 326 that is spun, that is, spun on itself, in the direction of arrow 327. According to the present Invention, the magnet 326 is located within a cavity of a magnetic roller that is not shown in the figure, its axis of rotation / rotation about itself generally being normal to the axis of the roller. Figure 8b is another illustration of fabricating a hemispherical image with the illusion of depth using a magnet 370 that rotates on itself to form a dome-shaped magnetic field 311 that emanates into substrate 377. Magnet 370 has a rectangular cross section and is shown in three different positions 370a, 370b, and 370c as it rotates on itself. The magnet should rotate on itself at a substantially higher angular velocity than the rotation of the roller on which the rotating magnet is located, so that the magnetic pigment contained in the ink on the substrate would "feel" the Magnetic dome-shaped magnetic field 311 of the self-rotating magnet for a period of time when the self-rotating magnet is close to the substrate. Figures 8c and 8d are photographs of the impressions with gradually variable inclination of the flakes produced by the rotating magnet, which concentrically orients the flakes to form what is substantially a Fresnel parabolic mirror pattern, providing that way to images the illusion of depth. More specifically, Figure 8c is an inclined photograph with its upper edge towards the observer, while photograph 8d is inclined with its upper edge away from the observer.

Although the description provided hereinabove with reference to Figs. 6a-7b refers to a sectionalized magnetic roll, other embodiments of the invention provide a magnetic roll where one or more magnetic magnets are positioned within cavities formed in a cylindrical solid roll body, or a roll body that is assembled from individual sections that are permanently attached to each other.

Accordingly, this aspect of the invention generally provides an apparatus for orienting magnetic flakes contained in a printed fluid carrier onto a substrate in a printing process, the apparatus comprising a rotating roller to be positioned with an outer surface close to the substrate, said roller comprising: a cylindrical body comprising a cavity; a magnet positioned with the allowable twist inside the cavity to create a magnetic field of a predetermined configuration emanating from the outer surface of the roll into the substrate; and means for causing the magnet to rotate on itself inside the cavity during the printing process to orient the magnetic flakes in a predetermined pattern by forming an image with an illusion of depth on the substrate.

Continuous Printing

In the embodiments described earlier in this document, the magnetic parts of the roll, also referred to in this document as magnets, are discrete in that they are surrounded on the sides by non-magnetic material of the roll. Such magnets are suitable for forming on the surface of the substrate, in the areas where the ink or magnetic paint is dispersed, localized images or optical effects such as images of objects, logos, signs, spheres with the illusion of depth, etc. However, these magnets Discrete may not be appropriate for printing on continuous areas across or across substrate 212. Magnetic assemblies for this purpose are required to provide continuous alignment of magnetic particles as the substrate moves.

As we have discovered, such roller assemblies can contain permanent magnets integrated along or through a magnetic roller. Figures 9a and 9b show a roller 710 that provides alignment of magnetic flakes along the substrate, that is, in the direction of their movement during the online printing process. Roller 710 is assembled, or formed by, a plurality of sections 701, each with a ring-shaped magnetized portion 702. A partially assembled roll 710 is shown in Figure 9a. Sections 701 with magnetic rings 702 are assembled on an axis 703. Sections 701 are interlocked on axis 703 with keys not shown in Figures 9a, b. A drive sprocket 704 is attached to roller 710 to provide torque to said roller. Figure 7b shows the fully assembled roll 710 without cover. Magnetized roll parts 702 extend circumferentially around roll 710 to form an endless band, or a ring, to provide a continuous image on the substrate in the linear printing process.

The ring-shaped magnetized parts 702 can be formed using solid ring magnets, or can be assembled from small magnets, for example rectangular in shape, as shown schematically in Figures 9a and 9b. The magnets can have either side-to-side magnetization direction, ie along axis 701, or radial magnetization direction.

Figure 10 schematically illustrates the operation of one embodiment of the apparatus of the present invention for continuous line printing using the roller 710. As illustrated, a total number of the ring-shaped magnetic parts 702 on the roller determines the number of visible rows printed on a substrate 705. In Figure 10, roller 710 with magnetic rings 702 is located below substrate 705; the rest of the printing apparatus is not shown in the figure but could be similar to the apparatus 200 shown in Figure 1a. The stripes 706 are imprinted on the surface of the substrate 705 by a magnetic field emanating from the parts, or rings 702, magnetized, which orients scattered magnetic flakes on the surface of the substrate opposite the roller along the field lines magnetic. As shown in Figures 10, the stripes 705 on top of the substrate are printed with the ink or magnetic paint and are dark because the ink's magnetic particles are not yet aligned by the roller's magnetic field, and a large part of the light they reflect undergoes scattering. Roller 710 rotates in a direction shown by arrow 707 and substrate 705 moves in direction 708. Upon entering the field of the roller, magnetic ink or paint particles align in the direction of magnetic field lines. , which in this particular embodiment are located in the plane of the substrate where the substrate and the roller are close to each other and in contact. The alignment of the particles along the surface of the substrate increases their perceived reflectance and the printed stripe becomes shiny, as illustrated at the bottom of the substrate in Figure 10.

In other embodiments, a magnetic roller may include roller sections with continuous ring magnets 702, and roller sections having discrete magnets of selected shapes to form on the substrate a combination of localized images or optical effects and continuous optical features such as stripes 705.

Figures 11a and 11b schematically show an embodiment 810 of the magnetic roller, in which magnetized parts of the roller 803 extend across a working surface of the roller along its axis of rotation, from end to end of said work surface. In this document the term "work surface" is used to refer to the outer surface of the roll, or a part thereof, that makes contact with the substrate during printing. The cylindrical body 801 of the roller 810 has grooves 802 in which elongated magnets 803 are inserted. Grooves 801 and magnets 802 can have a corresponding decreasing section shape. Alternatively, the magnets can be fixed in place using screws, or adhesive, or other appropriate method as would be known to a person skilled in the art. When mounted on the printing apparatus, the roller may be located above or below the substrate.

Figure 12 schematically illustrates a portion of the printing apparatus that includes roller 810. In this case, roller 810 with magnets 803 inserted in grooves 802 is located below substrate 804. Substrate 804 approaches the roller. with strips 805 of wet magnetic ink printed on the substrate by one of the printing stations of the press just before the magnetic roller. When the stripes enter the magnetic field, the pigment particles align themselves along field lines; if the magnets 803 are magnetized in a plane normal to the axis of the roller tangentially to the outer surface. As a result of the alignment, the particles begin to reflect incident light in a way determined by the shape of the field. In a specific embodiment illustrated in Figure 12, the particles are oriented to generate the "rolling bar" effect described earlier in this document.

The system for curing wet ink with aligned particles was not shown in any detail in the images of this patent application to keep the attention on the design principles of the magnetic roller. However, it has to be mounted close to the roller. In some embodiments, the curing system illuminates a narrow area through the ink-containing substrate of particles aligned just above the last quadrant of the roll. In other embodiments, it may be mounted a certain distance after the mag roller.

Claims (5)

1. An apparatus for orienting magnetic flakes on a printed fluid carrier onto a substrate in a printing process, the apparatus comprising: a rotating roller (610) for positioning with an outer surface close to the substrate, the rotating roller (610) comprising a cylindrical body (501) comprising a cavity (506) characterized by a magnet (509) rotatably positioned within the cavity (506) to create a magnetic field of a predetermined configuration emanating from the outer surface of the rotating roller (610) into the substrate; and means for rotating on itself (504, 505, 507, 512) the magnet (509) within the cavity during the printing process to orient the magnetic flakes in a pattern. 2. The apparatus of claim 1, wherein the pattern comprises a Fresnel parabolic mirror pattern. The apparatus of any of claims 1-2, further comprising an electric motor positioned within the cylindrical body (501) to rotate the magnet (509) on itself. 4. A method of orienting magnetic flakes on a printed fluid carrier onto a substrate in a printing process, comprising: positioning a rotating roller (610) with an outer surface close to the substrate, the rotating roller (610) comprising a cylindrical body (501) comprising a cavity (506), and a magnet (509) rotatably positioned within the cavity (506) to create a magnetic field of a predetermined configuration emanating from the outer surface of the roller (610) into the substrate; and rotating the magnet (509) within itself in the cavity during the printing process to orient the magnetic flakes in a pattern. 5. The method of claim 4, wherein the predetermined pattern comprises a Fresnel parabolic mirror pattern.