Canadian Patents Database / Patent 2574140 Summary

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(12) Patent: (11) CA 2574140
(54) English Title: APPARATUS FOR ORIENTING MAGNETIC FLAKES
(54) French Title: APPAREIL D'ORIENTATION DE PAILLETTES MAGNETIQUES
(51) International Patent Classification (IPC):
  • G03G 19/00 (2006.01)
  • B42D 25/369 (2014.01)
  • B42D 25/373 (2014.01)
  • B05D 3/14 (2006.01)
  • B41F 19/00 (2006.01)
  • B41M 3/14 (2006.01)
  • B44D 3/22 (2006.01)
  • B44F 1/02 (2006.01)
  • B44F 1/10 (2006.01)
  • B44F 7/00 (2006.01)
(72) Inventors :
  • RAKSHA, VLADIMIR P. (United States of America)
  • HOLMAN, JAY M. (United States of America)
  • COOMBS, PAUL G. (United States of America)
  • MARKANTES, CHARLES T. (United States of America)
  • PHILLIPS, ROGER W. (United States of America)
(73) Owners :
  • VIAVI SOLUTIONS INC. (United States of America)
(71) Applicants :
  • JDS UNIPHASE CORPORATION (United States of America)
(74) Agent: GOWLING WLG (CANADA) LLP
(74) Associate agent: GOWLING WLG (CANADA) LLP
(45) Issued: 2015-03-17
(22) Filed Date: 2007-01-16
(41) Open to Public Inspection: 2007-07-17
Examination requested: 2011-12-29
(30) Availability of licence: N/A
(30) Language of filing: English

(30) Application Priority Data:
Application No. Country/Territory Date
60/759,356 United States of America 2006-01-17
60/777,086 United States of America 2006-02-27
11/552,219 United States of America 2006-10-24
11/278,600 United States of America 2006-04-04
11/560,927 United States of America 2006-11-17

English Abstract

A printing apparatus includes a magnetic rotatable roller with a smooth even outer surface for aligning magnetic flakes in a carrier, such as an ink vehicle or a paint vehicle to create optically variable images in a high-speed, linear printing operation. Images can provide security features on high-value documents, such as bank notes. Magnetic flakes in the ink are aligned using magnetic portions of the roller, that can be formed by permanent magnets embedded in a non-magnetic roller body, or selectively magnetized portions of a flexible magnetic cover of the roller. In some embodiments, the roller is assembled for a plurality of interchangeable sections, which can include spinning magnets. Selected orientation of the magnetic pigment flakes can achieve a variety of illusive optical effects that are useful for decorative or security applications.


French Abstract

Un appareil d'impression comprend un rouleau pivotant magnétique ayant une surface extérieure lisse égale servant à aligner des paillettes magnétiques dans un porteur, comme un support d'encre ou un récipient de peinture pour créer des images variables d'un point de vue optique lors d'une opération d'impression linéaire haute vitesse. Les images peuvent fournir des caractéristiques de sécurité sur des documents de grande valeur, comme des billets de banque. Les paillettes magnétiques de l'encre sont alignées à l'aide des parties magnétiques du rouleau, qui peuvent être formées par des aimants permanents intégrés dans un corps de rouleau non magnétique ou des portions magnétisées de manière sélective d'un revêtement magnétique du rouleau. Dans certaines réalisations, le rouleau est assemblé pour former une pluralité de sections interchangeables, qui peuvent comprendre des aimants tournants. L'orientation sélectionnée des paillettes de pigments magnétiques peut produire une variété d'effets optiques illusoires qui sont utiles à des fins de décoration ou de sécurité.


Note: Claims are shown in the official language in which they were submitted.



WE CLAIM:

1. An apparatus for orienting magnetic flakes in a fluid carrier printed on a
substrate in a
continuous printing process, the apparatus comprising:
an axle; and,
a rotatable roller for positioning with an outer surface proximate to the
substrate, said
roller comprising a cylindrical body formed by a plurality of roller sections,
each roller
section having a generally cylindrical shape and comprising one or more
cavities having
permanent magnets inserted therein, the permanent magnets shaped for forming
magnetic
fields of pre-determined configurations emanating from an outer surface of the
roller for
orienting the magnetic flakes in selected patterns, said roller sections
detachably
positioned side by side on the axle;
wherein at least some of the roller sections are interchangeable for forming
different
combinations of the magnetic flake patterns on the substrate.
2. An apparatus according to claim 1, wherein the roller sections have outer
surfaces which
together provide a substantially even outer surface of the roller.
3. An apparatus according to claim 1, further comprising a flexible sheet of
non-magnetic
material encasing the roller sections for providing a substantially even outer
surface of the roller.
4. An apparatus according to claim 3, wherein the roller sections are
rotatably mounted on the
axle with a bearing, further comprising a gear for rotating the sections about
the axle.
5. An apparatus according to claim 4, wherein the roller sections have first
locking means for
mutually locking said sections in a fixed relative orientation for rotating
together.
6. An apparatus according to claim 1, wherein at least one of the permanent
magnets is shaped so
that the magnetic field emanating therefrom orients the magnetic flakes during
the printing
process to form an image, indicia, or a logo.
7. An apparatus according to claim 6, wherein the image provides a dynamic
optical effect when
viewed at a varying viewing angle or at a varying illumination angle.
8. An apparatus according to claim 7, wherein the image comprises a rolling
object or a flip-flop.
28

9. An apparatus according to claim 7, wherein the dynamic optical effect
comprises color
shifting or color changing.
10. An apparatus according to claim 6, wherein the image provides an illusive
optical effect.
11. An apparatus according to claim 10, wherein the illusive optical effect is
an illusion of depth
exceeding the substrate thickness.
12. An apparatus according to claim 5, wherein the plurality of roller
sections include a first
section wherein one of the plurality of cavities extends radially forming a
passage from the axle
to the outer surface of the first section, the apparatus further comprising:
a shaft rotationally positioned within the passage, the shaft having an outer
end whereto
one of the permanent magnets is attached, and an inner end; and,
a gear means rotationally coupling the axle with the shaft for spinning the
one of the
permanent magnets when the section is rotated about the axle.
13. An apparatus according to claim 12, wherein the gear means comprises a
first bevel gear
mounted on the axle, and a second bevel gear mounted at the inner end of the
shaft.
14. An apparatus according to claim 12, wherein the gear means is positioned
in a recess in the
first section.
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Note: Descriptions are shown in the official language in which they were submitted.

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APPARATUS FOR ORIENTING MAGNETIC FLAKES
FIELD OF THE INVENTION
[01] The present invention relates generally to optically variable
pigments, films, devices,
and images, and more particularly to an apparatus for aligning or orienting
magnetic flakes, such
as during a painting or printing process, to obtain an illusive optical
effect.
BACKGROUND OF THE INVENTION
[02] Optically variable devices are used in a wide variety of applications,
both decorative and
utilitarian. Optically variable devices can be made in variety of ways to
achieve a variety of
effects. Examples of optically variable devices include the holograms
imprinted on credit cards
and authentic software documentation, color-shifting images printed on
banknotes, and
enhancing the surface appearance of items such as motorcycle helmets and wheel
covers.
[03] Optically variable devices can be made as film or foil that is
pressed, stamped, glued, or
otherwise attached to an object, and can also be made using optically variable
pigments. One
type of optically variable pigment is commonly called a color-shifting pigment
because the
apparent color of images appropriately printed with such pigments changes as
the angle of view
and/or illumination is tilted. A common example is the "20" printed with color-
shifting pigment
in the lower right-hand corner of a U.S. twenty-dollar bill, which serves as
an anti-counterfeiting
device.
[04] Some anti-counterfeiting devices are covert, while others are intended
to be noticed.
Unfortunately, some optically variable devices that are intended to be noticed
are not widely
known because the optically variable aspect of the device is not sufficiently
dramatic. For
example, the color shift of an image printed with color-shifting pigment might
not be noticed
under uniform fluorescent ceiling lights, but more noticeable in direct
sunlight or under single-
point illumination. This can make it easier for a counterfeiter to pass
counterfeit notes without
the optically variable feature because the recipient might not be aware of the
optically variable
feature, or because the counterfeit note might look substantially similar to
the authentic note
under certain conditions.
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[05] Optically variable devices can also be made with magnetic pigments that
are aligned with
a magnetic field after applying the pigment (typically in a carrier such as an
ink vehicle or a paint
vehicle) to a surface. However, painting with magnetic pigments has been used
mostly for
decorative purposes. For example, use of magnetic pigments has been described
to produce
painted cover wheels having a decorative feature that appears as a three-
dimensional shape. A
pattern was formed on the painted product by applying a magnetic field to the
product while the
paint medium still was in a liquid state. The paint medium had dispersed
magnetic non-spherical
particles, commonly referred to as flakes, that aligned along the magnetic
field lines. The field
had two regions. The first region contained lines of a magnetic force that
were oriented parallel
to the surface and arranged in a shape of a desired pattern. The second region
contained lines that
were non-parallel to the surface of the painted product and arranged around
the pattern. To form
the pattern, permanent magnets or electromagnets with the shape corresponding
to the shape of
desired pattern were located underneath the painted product to orient in the
magnetic field non-
spherical magnetic particles dispersed in the paint while the paint was still
wet. When the paint
dried, the pattern was visible on the surface of the painted product as the
light rays incident on
the paint layer were influenced differently by the oriented magnetic
particles.
[06] Similarly, a process for producing of a pattern of flaked magnetic
particles in
fluoropolymer matrix has been described. After coating a product with a
composition in liquid
form, a magnet with desirable shape was placed on the underside of the
substrate. Magnetic
flakes dispersed in a liquid organic medium orient themselves parallel to the
magnetic field lines,
tilting from the original planar orientation. This tilt 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 planar oriented flakes reflected incident light back to the
viewer, while the
reoriented flakes did not, providing the appearance of a three dimensional
pattern in the coating.
[07] While these approaches describe methods and apparatus for formation of
three-
dimensional-like images in paint layers, they are not suitable for high-speed
printing processes
because they are essentially batch processes.
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[08] U.S. Patent 3,873,975 to Miklos et al issued March 25, 1975 discloses
a magnetic system
for authentication and interrogation of security documents such as credit
cards, airline tickets etc,
which utilizes magnetic recording of security patterns in a record medium
having magnetically
detectable permanent fixed information pattern. Such a record medium is
prepared by providing
a sheet having a non-magnetic backing and a layer thereon incorporating
magnetically
anisotropic magnetizable particles which are temporarily free to rotate. The
magnetizable
particles at selected locations in the layer are magnetically aligned to form
a fixed information
pattern, such as an alphameric character, by passing the sheet adjacent a
rotatable 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 adjacent
thereto. The cylinder is rotated as the sheet is passed adjacent thereto to
apply the magnetic fields
in the layer to physically align the magnetizable particles at the selected
locations to implant the
fixed information pattern in the layer. The imprinted patterns form a security
feature that can be
magnetically read for document authentication.
[09] The apparatus disclosed by Miklos et al, although apparently enabling
a continuous
magnetic printing of pre-determined two-dimensional security patterns by
orienting magnetic
particles in a recording media, has certain disadvantages.
[10] First, the device of Miklos can magnetically imprint only
substantially two-dimensional
patterns copying geometrical arrangements of the magnets mounted on the
cylinder, each
magnet essentially providing a "dot" in the pattern imprinted in the magnetic
layer. It would be
very difficult if at all possible to use this technology to provide pre-
determined substantially
three-dimensional (3D) or complex arrangements of magnetic flakes that are
required for
providing optical images with variable or illusive optical effects, such as
rolling objects and
images with illusion of depth.
[11] Second, in the device of Miklos et al the magnets are mounted on the
outer surface of the
cylinder, and are therefore projecting therefrom. This can be highly
disadvantageous in contact
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printing, when the cylinder is in contact, possibly under some pressure, with
the sheet whereupon
the magnetic layer is disposed.
[12] Third, since in the device of Miklos the magnets are fixedly attached to
the surface of the
cylinder, it cannot be used to form illusive images that can be produced by
spinning magnets, as
described in co-pending US patent application 11/278,600 filed April 4, 2006.
[13] European patent application EP 1493590 describes a method and means for
producing a
magnetically induced design in a coating containing magnetic particles that
also uses a rotatable
cylinder to orient magnetic particles in pre-determined patterns. The device
comprises a body of
a composite permanent magnetic material having at least one flat or curved
surface engraved
with the pattern corresponding to the pattern of desirable indicia. The
magnetic material is
magnetized in the direction perpendicular to the surface. Irregularities in
the surface, made with
an engraving, produce changes in the direction and strength of the resulting
magnetic field.
These changes cause different alignment of magnetic particles in different
parts of the wet ink
that make possible a formation of an image with a shape corresponding to the
shape of
engraving. The device can be a permanently magnetized flexible plate mounted
on a rotatable
cylinder of a printing press, with the engraved surface having surface
irregularities in the shape
of the indicia located at the outer surface of the cylinder. The approach of
EP 1493590 has
however certain limitations. The steps required to produce the engravings in
the permanent
magnetic material can be cumbersome; furthermore, the printing with the
engraved surfaces is
generally directed to reproducing the engraved indicia or drawings, and is
limited in terms of
optical effects it can produce. For example, the inventors of this invention
have found that, when
printing in accordance with the teachings of EP 1 493 590 using color-shifting
inks, a very poor
color-shifting effect resulted. A color-shifting affect has the best
appearance, i.e. large color
travel and high chroma value, when the particles providing the effect are
parallel or almost
parallel to the surface of the substrate, which is hard to achieve using the
device of EP 1 493 590.
[14] It is therefore desirable to provide an apparatus for a high-speed in-
line printing and
painting that re-orients magnetic pigment flakes in pre-determined
substantially 3D patterns for
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providing illusive and/or variable optical effects, and which would not
involve using printing
surfaces with protruding magnets.
[15] It is also desirable to provide a rotatable roller for a high-speed in-
line printing that can
be easily assembled and disassembled for forming various combinations of
optical images and
variable or illusive optical effects.
[16] It is another object of the present invention to provide an apparatus
for continuous in-
line printing that uses spinning magnets to orient magnetic flakes in pre-
determined substantially
3D patterns for providing optical images with the illusion of depth.
SUMMARY OF THE INVENTION
[17] In accordance with the invention, an apparatus is provided for
orienting magnetic
flakes in a fluid carrier printed on a substrate in a printing process, the
apparatus comprising a
rotatable roller for positioning with an outer surface proximate to the
substrate, said roller
comprising one or more magnetized portions for creating a magnetic field of a
pre-determined
configuration emanating from the outer surface of the roller into the
substrate to orient the
magnetic flakes in a selected pattern, wherein the outer surface of the roller
is substantially even
for providing a substantially uniform contact with the substrate across the
outer surface of the
roller during the linear printing process.
[18] In accordance with one aspect of the invention, the rotatable roller
comprises a
plurality of magnetized portions separated by non-magentized or differently
magnetized portions
of the roller for creating magnetic fields of pre-deterniined configurations
emanating into the
substrate for arranging the magnetic flakes on the substrate in predetermined
patterns forming an
image and/or an illusive optical effect.
[19] In accordance with one aspect of the invention, the rotatable roller
comprises a
cylindrical body encased by a flexible sheet of a magnetic material which is
selectively
magnetized for providing the magnetized portions of the roller.

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[20] In accordance with another aspect of this invention, the rotatable
roller comprises a
cylindrical body of non-magnetic material having one or more cavities formed
therein, and one
or more permanent magnets positioned in said one or more cavities for forming
the one or more
magnetized portions of the roller, the one or more permanent magnets shaped
for creating the
magnetic field of the pre-determined configuration.
[21] In accordance with another aspect of this invention, the rotatable
roller comprises a
plurality of roller sections detachably positioned side by side for forming a
cylindrical body of
the roller, wherein each roller section comprises one or more magnetized
portions for creating a
magnetic field of a pre-determined configuration emanating from the outer
surface of the roller
into the substrate to orient the magnetic flakes in a selected pattern; the
outer surface of the roller
is substantially even for providing a substantially uniform contact with the
substrate across the
outer surface of the roller during the linear printing process; the roller
sections are
interchangeable for forming different combinations of the magnetic flake
patterns on the
substrate. The magnetized portions can be formed by one or more permanent
magnets
positioned in cavities formed within the roller sections, each of the magnets
shaped for providing
a pre-determined configuration of the magnetic field in and about the
substrate having magnetic
flakes dispersed thereon.
[22] In accordance with an aspect of the invention, the one or more
cavities are shaped to
fixedly hold the one or more permanent magnets flush with an outer surface of
the cylindrical
body.
[23] In accordance with an aspect of the invention, the one or more magnets
comprise a
first magnet which is recessed relative to an outer surface of the cylindrical
body of the roller.
[24] In accordance with another aspect of this invention, the one or more
permanent
magnets comprise a first magnet that is rotatably positioned within one of the
cavities, and a
means for spinning the first magnet within the cavity during the printing
process for providing an
illusion of depth to the image formed by the first magnet on the substrate in
the linear printing
process.
[25] In accordance with an aspect of the invention, the roller sections are
rotatably mounted
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on the axle with a bearing, and the apparatus further comprises a first gear
means for rotating
the cylindrical body of the roller about the axle, and a second gear means
coupling the first
magnet with the axle for spinning the first magnet about an axis normal to the
outer surface of
the roller when the roller is rotated about the axle.
[26] In one embodiment of this aspect of the invention, the cavity wherein
the first
magnet is rotatably positioned extends radially forming a passage from the
axle to the outer
surface of the first section, the apparatus further comprising a shaft
rotationally positioned
within the passage, the shaft having an outer end whereto one of the permanent
magnets is
attached, and an inner end, a gear means rotationally coupling the axle with
the shaft for
spinning the one of the permanent magnets when the section is rotated about
the axle, and a gear
means for rotating the cylindrical body of the roller about the axle.
[27] Another aspect of the invention provides an apparatus for orienting
magnetic flakes
in a fluid carrier printed on a substrate in a printing process, the apparatus
comprising a rotatable
roller for positioning with an outer surface proximate to the substrate, said
roller comprising: a
cylindrical body comprising a cavity; a magnet rotatably positioned within the
cavity for creating
a magnetic field of a pre-determined configuration emanating from the outer
surface of the roller
into the substrate; and, a means for spinning the magnet within the cavity
during the printing
process for orienting the magnetic flakes in a predetermined pattern forming
an image with an
illusion of depth on the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[28] The invention will be described in greater detail with reference to
the accompanying
drawings which represent preferred embodiments thereof, wherein:
[29] Fig. la is a simplified diagram showing a side view of a linear
printing apparatus
incorporating a magnetic roller according to an embodiment of the present
invention;
[30] Fig. lb is a simplified perspective of one embodiment of the roller
with magnetic
assemblies for use in the apparatus illustrated in Fig. la;
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[31] Fig. 2a is a simplified perspective view of a magnetic roller
incorporating embedded
permanent magnets;
[32] Fig. 2b is a simplified perspective view of a portion of the roller
shown in Fig. 2a
with a embedded magnet having a star-shaped outer surface;
[33] Fig. 2c is a simplified side view of magnetic assembly for printing
illusive three-
dimensional images according to an embodiment of the present invention;
[34] Fig. 2d is a simplified side view of a magnet for printing illusive
three-dimensional
images according to another embodiment of the present invention;
[35] Fig.3 is a simplified perspective view of a roller having a
selectively magnetized
outer shell according to an embodiment of the present invention;
[36] Fig. 4a is a simplified cross section of a printed image that will be
referred to as a
"flip-flop";
[37] Fig. 4b is a simplified cross section of a printed "rolling bar" image
with an illusion
of depth;
[38] Fig. 4c is a diagram of the magnetic field from the magnetized sheet
having a two-
pole orientation;
[39] Fig. 5a is a cross-sectional side view of one roller section
incorporating static
magnets according to another embodiment of the present invention;
[40] Fig. 5b is a perspective view of the roller section illustrated in
Fig. 5a;
[41] Fig. 5c is a simplified diagram showing the sectionalized roller
assembly;
[42] Fig. 6a is a cross-sectional side view of one roller section
incorporating spinning
magnets according to another embodiment of the present invention;
[43] Fig. 6b is a perspective view of the roller section illustrated in
Fig. 6a;
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[44] Fig. 7a is a perspective view schematically illustrating a partially
assembled
sectionalized roller with spinning magnets;
[45] Fig. 7b is a perspective view schematically illustrating a fully
assembled
sectionalized roller with spinning magnets;
[46] Fig. 8a is a drawing illustrating the axial-symmetric hemisphere-
shaped alignment of
magnetic particles dispersed in a thin layer of the ink printed upon a
substrate;
[47] Fig. 8b is a perspective view of a same spinning magnet at three
angles of its rotation
after the magnet completed a single revolution around the vertical axis, with
a sheet having
flaked ink applied thereto disposed in the dome-shaped field;
[48] Figs. 8c and 8d are photographs of the prints with hemisphere-shaped
alignment;
[49] Fig. 9a is a perspective view schematically illustrating a partially
assembled
sectionalized roller with ring magnets continuously encircling the roller;
[50] Fig. 9b is a perspective view schematically illustrating a fully
assembled body of a
sectionalized roller with ring magnets continuously encircling the roller;
[51] Fig. 10 is a simplified diagram illustrating the printing of
continuous images
extending along the substrate in a linear printing apparatus according to an
embodiment of the
present invention using the roller shown in Fig. 8a;
[52] Fig. 1 la is a simplified perspective view of a roller having
continuous magnets
across its working surface;
[53] Fig. llb is a simplified side view of the roller shown in Fig. 10a;
[54] Fig. 12 is a simplified diagram illustrating the printing of
continuous images
extending across the substrate in a linear printing apparatus according to an
embodiment of the
present invention using the roller shown in Fig. 10a.
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DETAILED DESCRIPTION
[55] Exemplary embodiments of the apparatus of the present invention for
orienting magnetic
flakes 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 Figs. la-1c.
[56] Fig. la is a simplified side-view schematic of a portion of a printing
apparatus 200
according to an embodiment of the present invention. An important part of the
apparatus of the
present invention is a magnetic roller, which is understood herein as a roller
having magnetized
portions and non-magnetized or differently magnetized portions. The term
"magnetized
portions" in relation to the roller of the present invention is used herein to
mean a permanent
magnet imbedded in the roller, or a selectively magnetized region of the
roller adjacent to its
surface, or an alternatively formed portion of a roller that has a pre-
determined magnetization
different from magnetization of surrounding it areas of the roller, so as to
form a pre-determined
magnetic field profile emanating from the roller.
[57] In the printing apparatus illustrated in Fig. la, the magnetic roller
of the present
invention is embodied as an impression roller 210. Said impression roller 210
includes magnets
202, 204, 206, 208, which are located inside the impression roller 210,
forming the magnetized
portions of the roller arranged in a pattern that correlates with a printed
image 220. A substrate
212, such as a continuous sheet of paper, plastic film, or laminate, moves
between a print
cylinder 214 and the impression roller 210 at high speed. The print cylinder
214 takes up a
relatively thick layer 213 of liquid paint or ink 215 from a source container
216; the liquid paint
or ink 215 contains platelet-like magnetic pigments, or flakes, for example as
described United
States patent 6,808,806, or in co-pending United States patent applications
serial numbers
20040051297, 20040166308, 20050123755, and 20060194040. The term "magnetic
pigment" is
used to mean a pigment that will align in a magnetic field. For convenience of
discussion, the
terms "printing" or "printed" will be used to generally describe the
application of pigments in a
carrier to a surface, which may include other techniques, including techniques
others might refer
to as "painting".
[58] The flakes are preferably reflective and are magnetically alignable or
orientable
within the optically transparent ink base, hereinafter referred to as the
carrier, as long as the ink

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or paint remain fluid. The flakes can also be absorptive and/or diffractive,
as described for
example in a commonly owned US Patent 6,902,807, and can include taggant or
taggent flakes,
as described in co-pending US patent applications 2005/0037192 and
2006/0035080, and/or
color-shifting flakes.
[59] The paint or ink is spread to the desired thickness on the print
cylinder 214 with a
blade 218. In accordance with this invention, the ink vehicle 215 can be clear
or dyed. During
printing of an image between the print cylinder 214 and the impression roller
210, the substrate
212 with a layer 213 of wet ink is moved into a magnetic field to form an
illusory image. When
the wet ink is exposed to a magnetic or electric field, flat magnetic or e-
field alignable particles
of the pigment align along magnetic lines of the field. The magnets in the
impression roller
thereby orient, i.e. selectively align, the magnetic pigment flakes in at
least part of the printed
image 220. Preferably, the magnetic field of the magnetic portions, e.g. 206,
emanating from the
outer surface of the roller into the substrate 212 is shaped to a desired,
desirable, or
predetermined configuration so as to orient the magnetic flakes in a selected
pattern, e.g.
providing an illusive optical effect. A tensioner 222 is typically used to
maintain the desired
substrate tension as it comes out of the impression roller 210 and the print
cylinder 214, and the
image on the substrate is dried with a drier 224. The drier could be heater,
for example, or the ink
or paint could be UV-curable, and set with a UV lamp.
[60] In another embodiment, a cylinder incorporating magnetic portions,
e.g. magnets
202, 204, 206 and 208, for aligning flakes in a liquid carrier 212 can be used
as or in place of the
tensioner 222 rather than as the impression roller 202. In yet another
embodiment, a magnetic
roller can be used as a third cylinder in the apparatus 200 located between
the heater 224 and the
print cylinder 214.
[61] Fig. lb shows a magnetic roller 232 that can be used in the apparatus
200; it has been
described in U.S. Patent 7,047,883, which is assigned to the assignee of the
present application.
The roller could be a print cylinder or tensioner, as discussed in conjunction
with Fig. la, or
another roller in a printing system that contacts the print substrate before
the ink or paint is fixed.
Magnetic assemblies 234, 236, 238, 240, 241 are attached to the roller with
screws 242, which
allow the magnetic assemblies to be changed
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without removing the roller from the printer. The magnetic assemblies could be
configured to
produce flip-flop 234, 236 or rolling bar 238 images, or could be patterned
magnetic material
240, 241 that produces a patterned image on the printed substrate, or other
selected magnetic
configuration. The magnetic structures on the roller are aligned to the sheet
or roll to provide the
desired magnetic field pattern to fields printed on the substrate with
magnetic pigment flakes.
The illustrated patterns represent flat patterns that follow the curve of the
circumference of the
roller.
[62] It is advantageous in applications to have the outer surface 244 of
the roller 232
sufficiently even or smooth, otherwise it can potentially deform or even
damage the substrate
212. For these applications, it is preferred that the outer surface 244 does
not have any protruding
portions, resulting in a substantially even and uniform contact of the roller
with the substrate
across the outer surface of the roller.
[63] Accordingly, in one preferred embodiment of the invention permanent
magnets are
built into a cylindrical body of the roller to provide the magnetic field of a
pre-determined
configuration as required for forming a desired image or an optical effect;
alternatively, in
another preferred embodiment a roller with a suitable magnetizable surface
material is
selectively magnetized in pre-determined patterns. In the description
following hereinbelow, we
will describe various embodiments of rollers having magnetic portions and the
substantially even
outer surface for orienting magnetic flakes in a continuous in-line printing
process, e.g. using the
apparatus 200. Various configurations of permanent magnets imbedded or
inserted in the roller
or otherwise attached thereto, as well as selectively magnetized portions of
the roller, will be
generally referred to hereinafter as the magnetized, or magnetic, portions of
the roller, or simply
as the magnetized or magnetic portions. Preferably, the outer surface of the
magnetic rollers
described hereinbelow with reference to Figs. 2a-11 is substantially even and
does not have
projecting portions, and deviates from a best-fit cylindrical surface by less
than +\-0.5mm, and
more preferably by less than -IA- 0.1mm.
[64] According to the present invention, the magnetic rollers can be
divided in two
families: discrete and continuous. A discrete roller has one or more magnetic
portions, e.g.
magnets or magnetic assemblies positioned adjacently to the outer surface of
the roller and
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spatially separated from each other with non-magnetized or differently
magnetized portions of
the roller. The discrete roller is a roller that is used for forming multiple
images or optical effects
on the substrate in a repeated manner, e.g. like a checker board, wherein
every single image or a
part of the single image is aligned within margins of the magnetic field
emanating from a
particular magnetic portion of the roller through the outer surface of the
roller into the substrate,
e.g. as schematically illustrated in Figs. 2c and 2d. A continuous roller
provides non-interrupted
printing, for example producing a continuous line or ribbon, on the substrate
either along the
surface of the substrate, i.e. in the direction of the substrate 212 movement
in Fig. la, or across
the substrate, e.g. in the direction normal to the plane of Fig. la or at an
angle thereto.
[65] According to another aspect of the present invention, a magnetic
roller can be build
as a unit with a solid body with attached or imbedded magnets, or as an
assembly of several
identical or different section of the roller with build-in magnetic systems.
Convenience of the
sectional magnetic roller is obvious in its flexibility: the roller with
sections of one particular
magnetic portion configuration can easily be disassembled and re-assembled
again with
inclusion of sections with different magnetic portions, for forming a
different combination of
images and/or optical effects on the substrate.
[66] The magnets or magnetic assemblies in a discrete roller can be held
still, i.e. static
relative to the body of the roller, or positioned rotatably in a cavity in the
cylindrical body of the
roller for spinning or rotating within the body underneath the substrate
during the printing
process to provide an image with a striking illusion of depth, as described
hereinbelow.
[67] Fig. 2a schematically illustrates a magnetic roller 332 for orienting
magnetic flakes
according to an embodiment of the present invention. The magnetic roller 332
has a solid
cylindrical body 301, hereinafter also referred to as a cylindrical member or
drum, of preferably
non-magnetic material, wherein a plurality of cavities is formed, i.e. milled
out of the body 301
from its outer surface 333. Permanent magnets of pre-determined shapes, as
required for forming
the desired flake patterns, e.g. magnets 302 and 303, are inserted in the
cavities as shown by
dark-shaded areas of the roller 332, forming magnetic portions of the roller
332. In Fig. 2a, the
cavities are shown as dark-shaded areas with the magnets inserted therein,
e.g. the magnets 302,
303 and 335, with a cut-out in a portion of the body 301 shown for the benefit
of the viewer to
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illustrate the positions of the magnets, e.g. the cylindrical magnet 302 and
the prism-shaped
magnet 335, within the drum 301. The cavities have the pre-determined shape
and dimensions of
the permanent magnets, and the magnets are statically and immovably kept
therein. In some
embodiments, the magnets 302, 303 can be fixed in their position by glue,
screws, brackets, etc,
or can be press-fitted and kept in their positions by traction. The permanent
magnets 302, 303,
although shown by way of illustration having cylindrical and rectangular
shapes, have at least
their outer surfaces, e.g. as indicated by an arrow 335, shaped for creating
magnetic fields of pre-
determined configurations, so as to orient the magnetic flakes in desired 3D
patterns when the
roller is used in the printing apparatus 200. In the shown embodiment, the
roller 332 is mounted
on an axel 304 with bearings that are not shown in the figure, and a gear
wheel 305 fixedly
attached to the roller is further provided for rotating the roller 332 about
the axel 304 during the
printing process.
168] In one embodiment, the magnets 302, 303 are positioned flush with the
outer surface 333
of the body 301, so that the outer surface of the roller 332 with the magnets
303, 302 therein is
substantially even for providing substantially uniform contact with the
substrate 212 across the
outer surface of the roller 332 during the linear printing process. The term
"contact" is used
herein to mean either direct or indirect contact between two surfaces, i.e.
via an intermediate
sheet or plate. In another embodiment, at least one of the magnets 302, 303 is
recessed relative to
the outer surface 333 of the drum 301, and the recess is filled with a non-
magnetic filler, e.g. an
epoxy, tin, brass, or other, to make the outer surface of the roller
substantially even as described
hereinabove. The ability to have 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, for forming flake arrangements providing sharp
image
transitions, as for example for forming a flip-flop image, the ink-magnet
distance should be
minimized. However, for forming images or optical effects wherein transitions
in the image
should be smeared, e.g. for providing an illusion of depth as in a rolling bar
image, the magnets
are preferably positioned at a larger distance from the ink layer, for example
between 0.125" to
0.75" for a rolling bar image depending on particular requirements of the
graphics. The rolling
bar and flip-flop images, and magnet arrangements that can be used for their
fabrication are
described, for example, in the commonly owned US Patent 7,047,883.
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[69] Fig. 2b is a simplified perspective section of a portion of a roller
332' with a
magnetic assembly 244 embedded in the roller. The magnetic assembly has a
cross section in the
shape of a star, and it surface 244' is substantially flush with the outer
surface of the roller. The
magnetic assembly could be shaped permanently magnetized material, as
illustrated in FIG. 12F,
or have a tip section of SUPERMALLOY, MU-METAL, or similar material, as
illustrated in
FIG. 12E, below. The roller rotates in the direction of the first arrow 246
and a paper or film
substrate 248 travels 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 over
the surface of the
star-shaped magnetic assembly when the roller was proximate to the substrate,
and an illusive
optical feature 254 in the shape of a star was formed in the field. In a
preferred embodiment, the
magnetic pigment flakes are fixed while the magnetic assembly is in contact
with the substrate.
[70] In one embodiment, the illusive optical effect 254 is a star with an
apparent depth
much deeper than the physical thickness of the printed field. Such a star can
be formed, for
example, with the outer surface 244' of the magnet 244 is recessed relative to
the outer surface of
the roller 332'.
[71] Fig. 2c is a computer simulated side view of a magnetic assembly 256
with a
permanent magnet 258 providing the magnetic field that is directed to the
substrate 248 by a
patterned tip 260 of SUPERMALLOY or other high-permeability material. The
modeled
magnetic field lines 262 are shown for purposes of illustration only. Some
"supermagnet"
materials are hard, brittle, and generally difficult to machine into intricate
shapes.
SUPERMALLOY is much easier to machine than NdFeB magnets, for example, and
thus can
provide an intricate magnetic field pattern with sufficient magnetic field
strength to align the
magnetic pigment flakes in the desired pattern. The low remnant magnetization
of
SUPERMALLOY and similar alloys make them easier to machine, as well.
[72] FIG. 2d is a computer simulated side view of a magnetic assembly 264
with a shaped
permanent magnet 258'. The entire length of the magnet does not have to be
shaped, but only that
portion that produces the desired field pattern at the substrate 248. Although
some materials that
are commonly used to form permanent magnets are difficult to machine, simple
patterns may be
formed in at least the tip section. Other materials that form permanent
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and may provide sufficient magnetic strength to produce the desired illusive
optical effect.
Similarly, magnet alloys might be cast or formed into relatively complex
shapes using powder
metallurgy techniques.
[73] Another embodiment of the present invention is illustrated in Fig.3.
According to this
embodiment, a magnetic roller 352 is fabricated by wrapping a flexible sheet
5020 of magnetic
material with selectively magnetized portions 5030 around a cylindrical member
or drum 5010
which is preferably fabricated from a non-magnetic material. The flexible and
generally non-
magnetized, apart from the portions 503, sheet 5020 is encasing the drum 5010
and is held on its
surface by a pressure-sensitive adhesive. Before wrapping, areas 5030 of the
sheet 5020 were
selectively magnetized through to form magnetized portions of the sheet 5020
having
predetermined shapes, shown herein as dollar signs by way of example.
Assembled roller 352
has a smooth non-interrupted surface formed by the outer surface of the sheet
5020. A sheet with
one magnetization pattern can easily be replaced by another when required. In
another
embodiment, the flexible sheet of magnetizable material 5020 is first
uniformly magnetized in
one magnetic orientation, and then portions of the uniformly magnetized sheet
of a pre-
determined shape or shapes are selectively magnetized in another magnetic
orientation or
orientations, so that the magnetic portions 503 of the roller 352 are
separated from each other by
a differently magnetized portions of the sheet 5020.
[74] This method of forming a magnetic roller has many advantages. The magnets
formed in
the sheet 502 by selective magnetization do not require carving or removing
the material to vary
the magnetic field. An image 503 of an object, logo or indicia is made within
the magnetic
material of the sheet 502 so that the magnet provides a field that corresponds
to the object, logo,
or indicia when the field is used to align flakes in paint or ink, as
described in detail in co-
pending US Patent Application No. 11/560,927. Advantageously, the object, logo
or indicia
encoded into the flexible magnetic sheet 502 by way of selected magnetization
cannot be seen,
but is present and generates a magnetic field that aligns flakes placed on a
substrate in the field to
replicate the object, logo or indicia. The magnetic sheet 502 provides a
naturally even outer
surface of the roller 352, without protrusions and recesses, thereby enabling
bringing the roller
352 in an intimate contact with the substrate 212 of
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the printing apparatus 200 without the risk of deforming the substrate even
when the pressure is
applied. The co-pending US patent application 11/560,927 provides a detailed
description of
various methods of the selective magnetization of the sheet 502 to form
magnetized portions of
the sheet for aligning magnetic flakes on the substrate in pre-determined or
selected patterns
providing various images and/or optical effects.
[75] Generally, the magnetic flake pattern created on the substrate by a
magnetized portion or
portions of the roller in accordance with the present invention forms an image
of an object,
indicia, or a logo on the substrate, or adds an illusive optical effect such
as an illusion of depth or
motion 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 varying viewing angle
or at a varying
illumination angle. When the ink is illuminated by a light source and observed
with a naked eye
or with an optical instrument the differently aligned platelet-like shaped
magnetic pigment
particles or flakes reflect incident light differently. One portion of the
particles is so oriented
with respect to the substrate, to the light source and to the observer that it
reflects coming light
rays right into the eye of the observer. Another portion of the particles of
the print reflects light
rays in different directions because they are tilted at different angles
relative to the direction of
the observer. When the substrate with printed coating is tilted with respect
to the light source or
the observer the first portion of the pigment particles does not reflect the
light toward the
observer any more. These particles start to reflect the light in different
direction while the
particles of the second portion start to reflect the light rays in the
direction of the observer. When
particles are aligned gradually in the layer of the ink, tilting of the
substrate causes appearance of
an illusive motion effect. When particles are aligned along the lines of a
magnet that was shaped
in predetermined pattern a portion of the printed layer repeats the shape of
the magnet creating
an effect of three-dimensionality. In this region it appears as if the image
comes out of the
substrate toward the observer.
Examples of Printed Illusive Images
[76] By way of example, Figs. 4a,b illustrate some of the images or optical
effects that can be
produced using the hereinabove described embodiments of the rollers with
reference to Figs. la,
2a ¨ 3. Fig. 4a is a simplified cross sectional view shown in the US Patent
7,047,883 of a printed
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image 20 that is referred to as a flip-flop, and which is an example of a
dynamic optical effect
that can be produced by suitably orienting magnetic flakes in a fluid carrier
printed on a
substrate. The flakes are shown as short lines in the cross-sectional view.
The figures are not
drawn to scale. A typical flake might be twenty microns across and about one
micron thick,
hence the figures are merely illustrative.
[77] The flip-flop includes a first printed portion 22 and a second printed
portion 24, separated
by a transition 25. Pigment flakes 26 surrounded by carrier 28, such as an ink
vehicle or a paint
vehicle have been aligned parallel to a first plane in the first portion, and
pigment flakes 26' in
the second portion have been aligned parallel to a second plane; this results
in a substantially-3D
pattern of magnetic flakes that can be produced using suitably shaped magnetic
field emanating
from the outer surface of the aforedescribed magnetic rollers having
magnetized portions of pre-
determined shapes; examples of such magnetic structures are given in the US
Patent 7,047,883.
[78] Generally, flakes viewed normal to the plane of the flake appear bright,
while flakes
viewed along the edge of the plane appear dark. For example, light from an
illumination source
30 is reflected off the flakes in the first region to the viewer 32. If the
image is tilted in the
direction indicated by the arrow 34, the flakes in the first region 22 will be
viewed on-end, while
light will be reflected off the flakes in the second region 24. Thus, in the
first viewing position
the first region will appear light and the second region will appear dark,
while in the second tilted
viewing position the fields will flip-flop, the first region becoming dark and
the second region
becoming light. This provides a very striking visual effect. Similarly, if the
pigment flakes are
color-shifting, one portion may appear to be a first color and the other
portion another color
when viewed at a first viewing or illumination angle, and said portions may
appear to switch
colors when viewed at a second viewing or illumination angle. The process of
fabricating
diffractive flakes is described in detail in U.S. Pat. No. 6,692,830. U.S.
patent application
20030190473, describes fabricating chromatic diffractive flakes. Producing a
magnetic
diffractive flake is similar to producing a diffractive flake, however one of
the layers is required
to be magnetic.
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[79] The carrier is typically transparent, either clear or tinted, and the
flakes are typically
fairly reflective. For example, the carrier could be tinted green and the
flakes could include a
metallic layer, such as a thin film of aluminum, gold, nickel, platinum, or
metal alloy, or be a
metal flake, such as a nickel or alloy flake. The light reflected off a metal
layer through the
green-tinted carrier might appear bright green, while another portion with
flakes viewed on end
might appear dark green or other color. If the flakes are merely metallic
flakes in a clear carrier,
then one portion of the image might appear bright metallic, while another
appears dark.
Alternatively, the metallic flakes might be coated with a tinted layer, or the
flakes might include
an optical interference structure, such as an absorber-spacer-reflector Fabry-
Perot type structure.
[80] Fig. 4b is a simplified cross section of a printed image 42 of a
kinematic optical device
that is referred to as a "rolling bar" for purposes of discussion, according
to 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 aligned in a
curving fashion, in a
pattern substantially reproducing reflective planes of a Fresnel cylindrical
mirror. As with the
flip-flop, the region(s) of the rolling bar that reflect light off the faces
of the pigment flakes to the
viewer appear lighter than areas that do not directly reflect the light to the
viewer, creating an
impression of light reflected from a polished metallic cylinder. This image
provides a light
band(s) or bar(s) that appear to move, or "roll" across the image when the
image is tilted with
respect to the viewing angle, assuming a fixed illumination source(s).
[81] The bar may also appear to have depth, even though it is printed in a
plane. The virtual
depth can appear to be much greater than the physical thickness of the printed
image; this aspect
of the image is referred to as an illusive optical effect. The tilting of the
flakes in a selected
pattern reflects light to provide the illusion of depth or "3D", as it is
commonly referred to. A
three-dimensional effect can be obtained by having a shaped magnet or magnets
placed e.g. in a
cavity of the roller 332 in a recessed position at some distance from the
paper or other substrate
with magnetic pigment flakes printed on the substrate in a fluid carrier. The
flakes align along
magnetic field lines forming pre-determined 3D patterns, and thereby creating
the 3D image after
setting (e.g. drying or curing) the carrier. The image often appears to move
as it is tilted, hence
kinematic 3D images may be formed.
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[82] Alternatively, a substantially 3D effect can be obtained by suitably
magnetizing a
selected area or region of the magnetizable upper sheet 502 encasing the
roller 352, so that the
magnetic field emanating from the upper surface of the selectively magnetized
portion would
substantially reproduce the magnetic field of the recessed suitably shaped
permanent magnet or
magnets. By way of example, Fig. 4c shows a selectively magnetized sheet 30
wherein
magnetized portions of the sheet, which are shown by areas with high density
of magnetic force
lines, are formed so that the magnetic field emanating from the sheet 30 is
substantially a
magnetic field of a magnet having a two-pole orientation in the plane of the
sheet 30.
Sectional Roller
[83] Referring now to Figs. 5a-c, another aspect of the invention provides
a sectionalized
magnetic roller for use in the alignment of magnetic flakes in pre-determined
patterns. The
sectionalized roller 410 schematically illustrated in cross-section in Fig. Sc
has a cylindrical body
420, also referred to herein as cylindrical member or drum, that is assembled
or formed from a
plurality of cylindrical roller sections 400 which are detachably positioned
side by side for
forming the cylindrical body of the roller 410. In Fig. Sc, the 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 inserting permanent magnets of pre-determined shapes therein, as
described
hereinabove with reference to a solid roller illustrated in Fig. 2a. The
roller sections 400 are
mounted on an axle 403 as shown in Figures 4a, 4b and 4c, and are positioned
side by side
thereon. Advantageously, the roller sections in the assembled roller are
interchangeable, so that
different combinations of images can be formed during printing.
[84] Figs. 5a and 5b schematically show a single roller section 400; in
this embodiment, the
roller section 400 has a partially hollow body 402 having cavities wherein
permanent magnets
401 of predetermined shape or shapes are fixedly positioned and held; the
cavities 401, which are
referred to in this specification using same reference labels as the
respective magnets located
therein, are open to an outer surface 444 of the roller section 400. For
illustrative purposes, the
magnets 401 positioned in the respectively shaped cavities are shown to be
cone-shaped. In
other embodiments the magnets 401 can be of any shape suitable for orienting
the magnetic
flakes in pre-determined patterns so to provide the desired images or optical
effects. The roller

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section 400 is recessed at one side to form a ring-like opening, or recess 450
that can be used to
facilitate the insertion of the magnets into the cavities 401. The roller
section 403 has a centrally
located cylindrical passage for the axle 403, which extends through the final
assembly 410 and
on which other cylindrical sections can be slidably mounted. The sections 400
have each a set of
pins 404 and matching holes 405, together forming a first locking means for
mutually locking the
roller sections in the assembly in a fixed relative orientation for rotating
together on the axle 403.
Pins 404 of a single section go into corresponding holes 405 of another
section locking sections
together as shown in Figure 5c thereby providing the roller integrity. In
other embodiments,
alternative locking means can be used to rotationally fix the roller sections
relative to each other
in the sectional roller assembly 410.
[85] Second locking means are provided for locking the sections 400 on the
axle 403 for
rotating together with the axle. In the shown embodiment the second locking
means are formed
by a key 406 that extends into suitably shaped slits provided in both the
cylindrical body 402 of
the roller section and in the axle 403 thereby preventing rotation of the
section 400 around the
axle 403. Alternatively, the key 406 can be integral with either the section
body 402 or the axle
403 projecting therefrom. The sectional roller enables assembly of sections
400 with different
magnetic configurations as shown in Fig. 4c, wherein differently shaped dark
shaded areas
represent permanent magnets of different shapes as desired for forming a
particular pattern of
magnetically induced images or optical effects in the magnetic layer on the
substrate 212.
[86] The aforedescribed sectionalized approach is very helpful for fabrication
of a roller with
a magnet spinning inside of the roller about an axis that is generally normal
to the outer surface
of the roller, so that in the linear printing process the outer surface of the
magnet is spinning in
the plane of the substrate 212 when the roller's rotation brings the magnet to
a proximate to the
substrate location, as illustrated e.g. by the magnet 206 in Fig. la.
[87] An embodiment 510 of a roller section with spinning magnets is
schematically shown in
Figs. 6a and 6b, wherein Fig. 6b provides a perspective view of the roller
section 510, while Fig.
6a shows the roller section 610 in cross-section. A cap-shaped section body
501 of the roller
section 510 is rotatably positioned, or mounted on an axle 502 using ball
bearing 503. The axle
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502 has a first 45 bevel gear 504 statically mounted, e.g. press-fitted,
thereon. The section body
501 receives a rotating moment from a gear wheel 505 fixedly attached thereto
and driven by a
pinion that is not shown in the drawings. The section body 501 has one or more
cavities 506
which extend radially forming a passage from the outer surface 544 of the
section 501 towards
the axle 502. A cylindrical shaft 507 is positioned within the passage 506.
The shaft 507 is
rotationally coupled to the section body 501 by a ball bearing 508. A
permanent magnet 509 of is
attached to one end of the shaft 507; the magnet 509 is hereinafter also
referred to as the first
magnet. In the shown embodiment, the first magnet 509 is recessed relative to
an outer surface of
the cylindrical body of the roller. A second 45 bevel gear 5100 is provided
at the other end of
the shaft 507. Gears 5100 and 504 have a matching pitch; they form gear means,
hereinafter also
referred to as second gear means, for coupling the first magnet 509 with the
axle 502 for
spinning the first magnet about an axis normal to the outer surface of the
roller 610 when the
roller is rotated about the axle. A cover sheet 511 encases the section body
501 in a final roller
assembly providing a smooth and even outer surface of the sectionalized
roller, as illustrated in
Figs. 7a and 7b. In different roller assemblies, the cover sheet 511 can have
a different thickness
to space the magnets 506 from the substrate 212, in dependence on the magnets
strength, ink
viscosity, pigment particles' magnetic properties, press running rate, and
other factors. The
magnets 506 are preferably recessed within the body 501, so that their outer
surface is separated
from the cover 511 by a gap. The gear wheel 505, hereinafter referred to as
the first gear means,
is used for rotating the cylindrical body of the roller 610 about the axle
502.
[88] When the gear 505 is driven, it rotates the section body 501 on the axle
502 that remains
static; the rotational motion of the body 501 is translated by the bevel gears
504, 5100 to the
shafts 507, which spin about their radially oriented axes, thereby spinning
the magnets 509 inside
of the cylindrical passages, or cavities 507, while simultaneously moving in a
circle orbit with
the section 501 about the axle 502 along a planetary-like trajectory creating
a magnetic field of a
desired dome-like configuration emanating from the outer surface of the
roller, and into the
substrate 212 at pre-determined locations when the rotation of the roller
brings the magnet into
proximity to the substrate with the magnetically alignable flakes dispersed
thereon. In another
embodiment, the magnets 509 can be driven independently on the rotation of the
roller body, e.g.
by an electrical motor or motors placed for example within the section body
501.
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[89] Figs. 7a and 7b schematically illustrate a sectionalized magnetic roller
610 assembled
from sections 510. Each of the sections of the roller has a set of matching
pins and holes not
shown in Figures 6a - 7b that are similar to those described with reference to
in Figs. 5a and 5b.
The sections 510 are assembled together side by side on the axle 503 so as to
form a cylindrical
body, also referred to therein as a cylindrical member, of the roller 610. The
assembled sections
are then covered by the cover 511 which encases the sections so as to form the
magnetic roller
610 and to provide a smooth even outer surface to the roller 610 even when the
magnets 509 are
recessed. Fig. 7a shows a partially assembled roller, while Fig. 7b shows a
completely assembled
roller. In Figs. 7a and 7b, the cover 511 is shown with a cut out for
illustration purposes.
[90] Spinning magnets can be advantageously used to form dome-shaped magnetic
fields,
which can be used for orienting magnetic flakes in a circular pattern forming
a Fresnel reflector,
thereby forming hemispherical images with illusion of depth, as described in
commonly assigned
co-pending US Patent Application 11/278,600. Fig. 8a reproduced from this
application
illustrates an axial-symmetric hemisphere-shaped alignment of magnetic
particles 323 dispersed
in a thin layer of the ink 324 printed upon a substrate 325 in a printed non-
concave Fresnel
mirror arrangement. Reference numeral 321 denotes the cross section of the
field having lines
322 which emanate from the magnet 326 which is rotated, i.e. spinned in the
direction of the
arrow 327. According to the present invention, the magnet 326 is positioned in
a cavity of a
magnetic roller which is not shown in the figure, with its axis of
rotation/spinning being
generally normal to the axle of the roller. Fig. 8b is another illustration of
the fabrication of a
semispherical image with the illusion of depth using a spinning magnet 370 to
form a dome-like
magnetic field 311 emanating into the substrate 377. The magnet 370 has a
rectangular cross-
section and is shown in three different positions 370a, 370b and 370 c during
the spinning. The
magnet should spin at a substantially faster angular velocity than that of the
rotation of the roller
wherein the spinning magnet is positioned, so that the magnetic pigment in the
ink on the
substrate would 'feel' the averaged dome-shaped magnetic field 311 of the
spinning magnet
during a period of time the spinning magnet is proximate to the substrate.
Figs. 8c and 8d are
photographs of the prints with gradually varying tilting of the flakes
produced by the spinning
magnet, which concentrically orients the flakes to form what is substantially
a Fresnel parabolic
mirror pattern, thereby providing the images with the illusion of depth. More
particularly Fig.
23

CA 02574140 2007-01-16
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Patent
8c is a photograph tilted with its upper edge toward the observer, while
photograph 8d is tilted
with its upper edge away from the observer.
[91] Although the description given hereinabove with reference to Figs. 6a-
7b relates to a
sectionalized magnetic roller, other embodiments of the invention provide a
magnetic roller
wherein one or more spinning magnets are positioned within cavities formed in
a solid
cylindrical body of the roller, or a roller body that is assembled from
individual sections that are
permanently attached to each other.
[92] Accordingly, this aspect of the invention generally provides an apparatus
for orienting
magnetic flakes in a fluid carrier printed on a substrate in a printing
process, the apparatus
comprising a rotatable roller for positioning with an outer surface proximate
to the substrate,
said roller comprising: a cylindrical body comprising a cavity; a magnet
rotatably positioned
within the cavity for creating a magnetic field of a pre-determined
configuration emanating from
the outer surface of the roller into the substrate; and a means for spinning
the magnet within the
cavity during the printing process for orienting the magnetic flakes in a
predetermined pattern
forming an image with an illusion of depth on the substrate.
Continuous printing
[93] In the embodiments described hereinabove, the magnetic portions of the
roller, also
referred to herein as the magnets, are discrete in the sense that they are
surrounded on the sides
by non-magnetic material of the roller. Such magnets are suitable for forming
localized images
or optical effects on the surface of the substrate where the magnetic ink or
paint is dispersed,
such as images of objects, logos, indicia, spheres with the illusion of depths
etc. However, such
discrete magnets may not be suitable for printing onto continuous areas along
or across the
substrate 212. Magnetic assemblies for this purpose need to provide continuous
alignment of
magnetic particles as the substrate moves.
[94] As we found, such roller assemblies may contain permanent magnets built-
in either along
or across magnetic roller. A roller 710 that provides alignment of magnetic
flakes along the
24

CA 02574140 2007-01-16
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Patent
substrate, i.e. in the direction of its movement during the in-line printing
process, is shown in
Figures 9a and 9b. The roller 710 is assembled, or formed of a plurality of
sections 701, each
with a ring-like magnetized portion 702. A partially assembled roller 710 is
shown in Fig. 9a.
Sections 701 with magnetic rings 702 are assembled on an axle 703. Sections
701 are locked on
the axle 703 with keys not shown in the figures 9a,b. A driving gear wheel 704
is attached to the
roller 710 in order to provide rotating moment to the roller. Fully assembled
roller 710 without
cover is shown in Fig. 9b. The magnetized portions 702 of the roller extend
circumferentially
about the roller 710 to form an endless band, or ring for providing a
continuous image on the
substrate in the linear printing process.
[95] The magnetized portions 702 shaped as rings can be formed using either
solid ring
magnets, or can be assembled from small, e.g. rectangular shaped magnets as
schematically
shown in Fig. 9a and 9b. The magnets may have either side to side, i.e. along
the axle 701, or
radial magnetization direction.
[96] Fig. 10 schematically illustrates the operation of on an embodiment of
the apparatus of
the present invention for continuous in-line printing using the roller 710. As
illustrated, a total
number of the ring-shaped magnetic portions 702 in the roller determines the
number of visible
rows printed in a substrate 705. In Fig. 10, the roller 710 with magnetic
rings 702 is positioned
underneath the substrate 705; the rest of the printing apparatus is not shown
in the figure but
could be similar to the apparatus 200 shown in Fig. la. The ribbons 706 are
printed on the
surface of the substrate 705 by a magnetic field emanating from the magnetized
portions, or rings
702, which orients magnetic flakes dispersed on the surface of the substrate
opposite to the roller
along the magnetic field lines. As shown in the figures 10, the ribbons 705 on
a top portion of the
substrate are printed with the magnetic ink or paint and are dark because the
magnetic particles
in the ink are not yet aligned by the magnetic field of the roller, and a
large portion of light that
they reflect is scattered. The roller 710 rotates in a direction shown by an
arrow 707 and the
substrate 705 moves in a direction 708. Coming into the field of the roller,
magnetic particles in
the ink or paint are aligned in the direction of magnetic lines of the field,
which are in this
particular embodiment lie in the plane of the substrate where the substrate
and roller are
proximate and in contact. Alignment of the particles along the surface of the
substrate increases

CA 02574140 2007-01-16
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their perceived reflectance and the printed ribbon becomes bright, as
illustrated in the lower
portion of the substrate in Fig.10.
[97] In other embodiments, a magnetic roller can 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 the ribbons 705.
[98] In yet another embodiment, the ring-shaped magnetic portions can be
formed by selective
magnetization in a flexible magnetizable sheet encasing a solid body of the
roller described
hereinabove with reference to Fig. 3.
[99] Figs. lla and 1 lb schematically show an embodiment 810 of the magnetic
roller,
wherein magnetized portions 803 of the roller extends across a working surface
of the roller
along its rotational axis from end to end of the working surface. The term
"working surface" is
used herein to mean the outer surface of the roller, or a portion thereof,
that comes in contact
with the substrate during printing. The cylindrical body 801 of the roller 810
has grooves 802
where elongated magnets 803 are inserted. The grooves 801 and the magnets 802
can have a
matching tapered shape. Alternatively, the magnets can be fixed in place by
screws, or adhesive,
or other suitable method as would be known to one skilled in the art. When
mounted in the
printing apparatus, the roller can be positioned above the substrate or
underneath it.
[100] Fig. 12 schematically illustrates a portion of the printing apparatus
that includes the roller
810. Here, the roller 810 with the magnets 803 inserted in the grooves 802 is
positioned
underneath the substrate 804. The substrate 804 approaches the roller with the
ribbons 805 of wet
magnetic ink, printed on the substrate by one of the press' printing stations
right before the
magnetic roller. When ribbons come into magnetic field the particles of the
pigment align
themselves along lines of the field; if the magnets 803 are magnetized in a
plane normal to the
roller's axis tangentially to the outer surface. As a result of the alignment,
the particles start to
reflect an incident light in a manner determined by the shape of the field. In
a particular
26

CA 02574140 2014-04-07
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Patent
embodiment illustrated in Fig. 12, the particles become oriented so to
generate the "rolling bar"
effect described hereinabove.
[101] The system for the curing of the wet ink with aligned particles was not
shown in any
detail in the pictures of this patent application in order to keep focus on
the principles of design
of the magnetic roller. However, it has to be mounted nearby the roller. In
some embodiments, it
illuminates a narrow area across the substrate with the ink containing aligned
particles right
above the last quadrant of the roller. In other embodiments, it can be mounted
at some distance
after the magnetic roller.
[102] It should be understood that each of the preceding embodiments of the
present invention
may utilize a portion of another embodiment. Of course numerous other
embodiments may be
envisioned without departing from the scope of the invention.
27

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Admin Status

Title Date
Forecasted Issue Date 2015-03-17
(22) Filed 2007-01-16
(41) Open to Public Inspection 2007-07-17
Examination Requested 2011-12-29
(45) Issued 2015-03-17

Abandonment History

There is no abandonment history.

Maintenance Fee

Description Date Amount
Last Payment 2018-12-20 $250.00
Next Payment if small entity fee 2020-01-16 $125.00
Next Payment if standard fee 2020-01-16 $250.00

Note : If the full payment has not been received on or before the date indicated, a further fee may be required which may be one of the following

  • the reinstatement fee set out in Item 7 of Schedule II of the Patent Rules;
  • the late payment fee set out in Item 22.1 of Schedule II of the Patent Rules; or
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Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Filing $400.00 2007-01-16
Registration of Documents $100.00 2007-04-04
Maintenance Fee - Application - New Act 2 2009-01-16 $100.00 2008-12-03
Maintenance Fee - Application - New Act 3 2010-01-18 $100.00 2009-12-17
Maintenance Fee - Application - New Act 4 2011-01-17 $100.00 2010-12-21
Maintenance Fee - Application - New Act 5 2012-01-16 $200.00 2011-11-23
Request for Examination $800.00 2011-12-29
Maintenance Fee - Application - New Act 6 2013-01-16 $200.00 2012-11-27
Maintenance Fee - Application - New Act 7 2014-01-16 $200.00 2013-12-18
Maintenance Fee - Application - New Act 8 2015-01-16 $200.00 2014-11-26
Final Fee $300.00 2014-12-23
Registration of Documents $100.00 2015-12-16
Maintenance Fee - Patent - New Act 9 2016-01-18 $200.00 2016-01-05
Maintenance Fee - Patent - New Act 10 2017-01-16 $250.00 2017-01-05
Maintenance Fee - Patent - New Act 11 2018-01-16 $250.00 2018-01-08
Maintenance Fee - Patent - New Act 12 2019-01-16 $250.00 2018-12-20
Current owners on record shown in alphabetical order.
Current Owners on Record
VIAVI SOLUTIONS INC.
Past owners on record shown in alphabetical order.
Past Owners on Record
COOMBS, PAUL G.
HOLMAN, JAY M.
JDS UNIPHASE CORPORATION
MARKANTES, CHARLES T.
PHILLIPS, ROGER W.
RAKSHA, VLADIMIR P.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.

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Claims 2007-01-16 5 155
Description 2007-01-16 27 1,446
Abstract 2007-01-16 1 22
Cover Page 2007-07-10 1 39
Description 2014-04-07 27 1,455
Claims 2014-04-07 2 78
Drawings 2014-04-07 13 272
Cover Page 2015-02-12 2 42
Assignment 2007-01-16 2 87
Correspondence 2007-02-15 1 26
Assignment 2007-04-04 5 160
Assignment 2015-12-16 7 271
Prosecution-Amendment 2011-12-29 9 346
Prosecution-Amendment 2013-10-10 3 124
Fees 2013-12-18 1 40
Correspondence 2014-12-23 1 36
Prosecution-Amendment 2014-04-07 27 922
Fees 2017-01-05 1 33
Correspondence 2015-12-16 9 391
Assignment 2016-01-11 7 274
Correspondence 2016-01-19 4 730
Correspondence 2016-01-19 4 757