Hot stamp imprinting system with locking cam reel hubs

A printing system for transferring ink from an inked ribbon supplied from a ribbon roll having a tubular core with an inner surface onto a substrate. The system includes a rotatable locking cam hub having a reel hub with a first surface engageable with the inner surface of the ribbon roll, and an eccentric hub having a second surface engageable with the inner surface of the ribbon roll. The eccentric hub is rotatable relative to the reel hub to provide a variable diameter between the first surface of the reel hub and the second surface of the eccentric hub. The diameter of the locking cam hub may be reduced by rotating the eccentric hub relative to the reel hub to permit disposal of the ribbon roll tubular core about locking cam hub, and the diameter of the locking cam hub may be increased by rotating the eccentric hub relative to the reel hub to engageably retain the inner surface of the ribbon roll by the first surface of the reel hub and the second surface of the eccentric hub. The locking cam hub includes a knurled outer surface to prevent rotational and axial slippage of the ribbon roll relative to the hub, and a spring member to prevent vibrationally induced rotation between the reel hub and the eccentric hub.

CROSS-REFERENCE TO RELATED APPLICATIONS 
The present application is related to the following several co-pending 
applications U.S. application Ser. No. 08/725,932, filed 7 Oct. 1996 and 
entitled "Hot Stamp Imprinting System With Backup Pad Assembly", U.S. 
application Ser. No. 08/725,928, filed 7 Oct. 1996 and entitled "Hot Stamp 
Imprinting System With Latchable Ink Ribbon Cassette and U.S. application 
Ser. No. 08/725,929, filed 7 Oct. 1996 and entitled Handle", and "Hot 
Stamp Imprinting System With Variable Typeholder", all assigned to the 
common assignee of the present invention and incorporated herein by 
reference. 
BACKGROUND OF THE INVENTION 
The invention generally relates to printing systems for transferring ink 
from an inked ribbon supplied from a ribbon roll onto a substrate, and 
more particularly to hot stamp imprinters with one or more hubs for 
engageably retaining a corresponding ribbon roll that supplies inked 
ribbon for imprinting onto a substrate. 
Hot stamp imprinter systems are used often by the packaging industry in 
labeling and packaging production lines to produce high quality imprints 
of lot numbers, expiration dates, production codes, and other variable 
information on a variety of substrates including labels and packages. Hot 
stamp imprinter systems include generally an inked ribbon disposed between 
a back-up pad and a heated print head assembly. And the print head 
assembly includes a typeholder having a typeface with alpha-numeric 
characters and logos, and the print head assembly is movable toward and 
away from the backup pad by a cam or pneumatic actuator mechanism to 
transfer ink from the inked ribbon onto a portion of substrate disposed 
between the inked ribbon and the backup pad. Between imprints, the inked 
ribbon is advanced from a ribbon supply roll to a ribbon take-up roll to 
position an unused portion of inked ribbon between the print head assembly 
and the backup pad for the next imprint. The substrate is also advanced 
between imprints by a substrate feed mechanism to position an adjacent 
portion of the substrate between the print head and the backup pad for the 
next imprint. 
The inked ribbon is comprised generally of a dye disposed on one side of a 
Mylar carrier, which is coiled about a tubular core member to form a 
ribbon supply roll. And the ribbon supply roll is disposed about a 
rotatable supply reel hub, and an end portion of the ribbon is coiled 
about a used ribbon roll formed by another tubular core member disposed 
about a take-up reel hub. According to one configuration of the present 
invention, the take-up reel is driven by a rewind belt from a feed roll. 
The feed roll, in turn, is driven through a coupling from a timing belt 
which converts linear travel of a pneumatic actuator to rotary movement 
required to drive the feed roll and the take-up reel. A series of idler 
guide rolls usually guide the ribbon between the print head and the backup 
pad as the ribbon is transferred from the ribbon supply roll to the used 
ribbon roll. And the supply reel incorporates a brake drum and brake arm 
assembly, which controls tension in the ribbon through the activation of a 
dancer arm within the ribbon path. 
The tubular core members that form the ribbon supply roll and the used 
ribbon roll are formed of cardboard and other materials. These tubular 
core members, however, do not always fit snugly over the hubs due to 
variation in the inner core diameter. These variations of inner core 
diameter result very often in slippage of the tubular core members 
relative to the respective hubs. More specifically, slippage of the used 
ribbon core member disposed about the take-up reel hub may result in 
improper or inadequate advancing of the ribbon between imprints, which 
adversely affects imprint quality. And slippage of the ribbon supply roll 
core member about the supply reel hub may result in excess or premature 
unwinding of the ribbon from the supply roll, which may cause improper 
ribbon tensioning or entanglement of the ribbon. A loose fitting tubular 
core member also has a tendency to deviate axially relative to the hub, 
which may result in a misfeeding of the ribbon or damage thereto. A loose 
fitting tubular core member also complicates installation of the ribbon 
supply roll and used ribbon roll, particularly in applications where the 
imprinter is oriented so that a loose fitting ribbon roll has a tendency 
to fall or otherwise separate from the hub under the influence of gravity 
and vibration during installation. This problem is especially significant 
in systems where the supply reel hub and take-up reel hubs are mounted on 
a removable ink ribbon cassette that is mateably engageable with the 
imprinter upon replacement of the ribbon supply roll and used ribbon roll. 
In a related problem, inked ribbon coiled loosely, whether or not the 
ribbon is coiled about a tubular core member, has a tendency to separate 
telescopically under the influence of gravity in some spatial 
orientations. 
In view of the discussion above among other considerations, there exists a 
demonstrated need for an advancement in the art of imprinting systems with 
a ribbon reel hub. 
It is therefore an object of the invention to provide a novel imprinting 
system with a ribbon reel hub that overcomes problems in the prior art and 
is economical. 
It is also an object of the invention to provide a novel imprinting system 
with a rotatable ribbon reel hub that compensates for variation in the 
diameter of ribbon roll tubular cores. 
It is another object of the invention to provide a novel imprinting system 
with a rotatable ribbon reel hub having a variable diameter locking cam 
hub for engageably retaining a ribbon roll without rotational or lateral 
slippage of the ribbon roll relative to the hub. 
It is another object of the invention to provide a novel imprinting system 
with a rotatable ribbon reel hub having an eccentric hub rotatable 
relative to a reel hub for increasing and decreasing a diameter of the 
hub, wherein the locking cam hub has one or more of a knurled outer 
surface and an axial outer edge portion for engaging and retaining an 
inner surface of a ribbon roll tubular core when the diameter of the 
locking cam hub is increased. 
It is a further object of the invention to provide a novel imprinting 
system having a locking cam hub formed by an eccentric hub rotatable 
relative to a reel hub for varying a diameter of the hub, wherein the 
locking cam hub includes a spring member interconnected between the reel 
hub and the eccentric hub for preventing vibrationally induced rotation 
therebetween. 
It is a further object of the invention to provide a novel imprinting 
system having a locking cam hub formed by an eccentric hub rotatable 
relative to a reel hub for varying a diameter of the hub, wherein a first 
support plate is engageable with a first side portion of a ribbon roll 
disposed over the locking cam hub and a second support plate biased toward 
and engageable with an opposing second side of the ribbon roll to prevent 
telescoping uncoiling of the ribbon roll. 
These and other objects, features and advantages of the present invention 
will become more fully apparent upon consideration of the following 
Detailed Description of the Invention with the accompanying Drawings, 
which may be disproportionate for ease of understanding, wherein like 
structure and steps are referenced by corresponding numerals and 
indicators.

DETAILED DESCRIPTION OF THE INVENTION 
The exemplary embodiments of the invention are disclosed in the context of 
imprinting systems and more particularly hot stamp imprinters for 
transferring ink from an inked ribbon onto a substrate, not shown in the 
drawing, wherein the inked ribbon is supplied from a ribbon roll. FIG. 1 
is an imprinting system 10 including generally one or more cam-locking 
hubs 100 for engageably retaining a corresponding ribbon roll 20, which 
has a tubular core with an inner surface 22 mountable about the hub. The 
inked ribbon rolls discussed herein include generally an inked ribbon 
coiled about a separate cardboard or plastic tubular core member 24, which 
defines the inner surface disposed about the hub. The invention, however, 
is applicable to ribbon rolls having a tubular core with an inner surface, 
which is defined by the ribbon roll in the absence of a separate tubular 
core member, and still more generally to any member having a tubular core 
with an inner surface, which is mountable about a hub. 
The locking cam hub 100 of FIG. 1 includes generally a reel hub 110 with a 
first surface 112 on a protruding member 114 engageable with the inner 
surface 22 of the ribbon roll 20, and an eccentric hub 120 with a second 
surface 122 engageable with the inner surface 22 of the ribbon roll 20. 
FIGS. 2a and 2b show the eccentric hub 120 rotatable relative to the reel 
hub 110 to provide a variable diameter between the first surface 112 of 
the reel hub 110 and the second surface 122 of the eccentric hub 120. The 
diameter between the first surface 112 of the reel hub 110 and the second 
surface 122 of the eccentric hub 120 is reduceable by rotating the 
eccentric hub 120 relative to the reel hub 110 to permit disposal of the 
ribbon roll tubular core 22 about the first surface 112 of the reel hub 
110 and the second surface 122 of the eccentric hub 120. The diameter 
between the first surface 112 of the reel hub 110 and the second surface 
122 of the eccentric hub 120 is increaseable by rotating the eccentric hub 
120 relative to the reel hub 110 to engageably retain the inner surface 22 
of the ribbon roll 20 by the first surface 112 of the reel hub 110 and the 
second surface 122 of the eccentric hub 120. 
According to the exemplary embodiments of FIGS. 1 and 2, a collar 130 
interconnects the reel hub 110 and the eccentric hub 120. A first end 
portion 132 of the collar 130 is rotatably and engageably disposed in a 
bore 115 of the reel hub 110, for example by screw threads on an inner 
surface of the bore 115 and on the outer surface of the collar 130. A 
second end portion 134 of the collar 130 is fixedly disposed in a bore 124 
of the eccentric hub 120. The collar 130 and the eccentric hub 120 may be 
similarly coupled by screw threads on the outer surface of the collar 130 
and on the inner surface of the bore 124 and fixedly engaged by one or 
more set screws 40. The eccentric hub 120 is a substantially cylindrical 
member and the bore 124 is located non-concentrically, which provides a 
camming action upon rotation of the eccentric hub 120. In alternative 
embodiments, the eccentric hub 120 may be formed of a body member with an 
irregular outer circumferential shape. 
According to the exemplary configuration of FIGS. 1 and 2, the diameter 
between the first surface 112 of the reel hub 110 and the second surface 
122 of the eccentric hub 120 is variable by rotating the fixedly coupled 
collar 130 and eccentric hub 120 in unison relative to the reel hub 110. A 
threaded collar 130 also permits adjusting telescopingly the axial 
dimension of the cam locking hub 100 for accommodating different width 
ribbon rolls 20. The eccentric hub 120 may include a recessed portion 127 
on an end portion thereof proximate the reel hub 110 to provide clearance 
between the eccentric hub 120 and the protruding portion 114 of the reel 
hub 110 during relative rotation therebetween. 
According to another aspect of the invention, a spring member 140 
interconnects the collar 130 and the reel hub 110 to prevent vibrationally 
induced rotation of the eccentric hub 120 relative to the reel hub 110. In 
the exemplary embodiment of FIG. 1, the spring member 140 is a stainless 
steel curved spring washer disposed between an end portion of the collar 
130 and the reel hub 110. These curved spring washers are available 
commercially from Associated Spring Raymond, Part No. U437-0150-S. 
According to a related aspect of the invention, one or both of the reel 
hub 110 and the eccentric hub 120 may have knurled outer surface portions 
116 and 126, respectively, to facilitate retention of the ribbon roll and 
to facilitate manual gripping during rotational adjustment of the diameter 
between the first surface 112 of the reel hub 110 and the second surface 
122 of the eccentric hub 120. The knurled surface tends to prevent axial 
and rotational slippage of the ribbon roll relative to the locking cam hub 
100, and also reduces the tendency of vibrationally induced rotation of 
the reel hub 110 relative to the eccentric hub 120. And according to 
another aspect of the invention, the first surface 112 on the protruding 
member 114 of the reel hub 110 includes an axial edge portion 117 for 
engaging the inner surface 22 of the ribbon roll 20. An angle defining the 
edge 117 may be increased or decreased to vary the extent to which the 
edge 117 engages or bites into the inner surface 22 of the ribbon roll 20. 
The edge portion 117 tends to bite into the inner surface 22 of the ribbon 
roll when the diameter between the first surface 112 and the second 
surface 122 are increased to provide relatively improved engageable 
retention of the ribbon roll 20 about the locking cam hub 100. 
According to another aspect of the invention, a first support plate 150 is 
fixed axially along the rotation axis of the reel hub 110 and extends 
substantially radially from the reel axis rotation axis. The first support 
plate 150 is engageable with a first side portion 25 of a ribbon roll 20 
engageably retained by the first surface 112 of the reel hub 110 and the 
second surface 122 of the eccentric hub 120. In the exemplary embodiment 
of FIG. 1, the first support plate 150 is coupled to the reel hub 110 by a 
drive pulley 160 threadedly engaged and fixedly retained to the reel hub 
110 by one or more set screws 40. The drive pulley 160 may include a 
recess 162 for receiving a drive belt for rotatingly driving the locking 
cam hub 100. According to a related aspect of the invention, the reel hub 
110 is rotatably coupled to an idler support shaft 170 fixedly coupled to 
a portion 30 of the printing system 10. One or more bearings 172, which 
bearings are separated by a bearing spacer 174 in FIG. 1, may rotatably 
couple the locking cam hub 100 to the idler support shaft 170. 
According to yet another aspect of the invention, the portion 30 of the 
printing system 10 is a ribbon roll cassette removably coupled to the 
printing system 10, wherein one or more locking cam hubs 100 are rotatably 
coupled to the ribbon roll cassette 30. In one configuration, a first 
locking cam hub, not shown in the drawing, retains a ribbon supply roll 
and a second locking cam hub retains a used ribbon roll, as shown in the 
drawing, wherein the first locking cam hub is an idler hub restrained from 
rotation by a combination brake drum and brake arm, which is activated by 
the movement of the ribbon past a dancer arm to maintain ribbon tension 
during transfer of ribbon from the supply roll to the used ribbon roll. 
According to this configuration, the second locking cam hub, which is an 
idler hub free to rotate in at least one direction, is rotatably driven by 
a rewind belt from the feed roll, which is coupled to a timing belt that 
converts linear travel of a pneumatic actuator to rotary movement of the 
feed roll and the ribbon take-up reel. 
According to still a further aspect of the invention shown in FIG. 3, a 
second support plate 180 is biased toward the first support plate 150 and 
is engageable with a second opposing side portion 27 of a ribbon roll 20, 
shown in phantom, engageably retained by the first surface 112 of the reel 
hub 110 and the second surface 122 of the eccentric hub 120. The second 
support plate 180 prevents the tendency of loosely coiled ribbon rolls 20 
from uncoiling telescopingly away from the first support plate 150, which 
may occur during installation, handling of a removable ribbon cassette or 
as a result of printing system spatial orientation. The second support 
plate 180 is aligned and rotatable about substantially the same rotation 
axis as the locking cam hub 100. In the exemplary embodiment, of FIG. 3, a 
plate hub 190 rotatably interconnects the second support plate 180 and a 
portion 60 of the printing system 10. The second support plate 180 is 
telescopingly coupled to the plate hub 190 by one or more shaft members 
192 and is biased away therefrom and toward the ribbon roll 20 by spring 
members 194. The plate hub 190 is rotatably coupled to a support shaft 70 
by bearings 72, and the plate hub 190 includes a concentric recessed 
portion 196 for receiving an end portion of the eccentric hub 120, which 
is also shown in phantom in FIG. 3. 
While the foregoing written description of the invention enables anyone 
skilled in the art to make and use what is at present considered to be the 
best mode of the invention, it will be appreciated and understood by 
anyone skilled in the art the existence of variations, combinations, 
modifications and equivalents within the spirit and scope of the specific 
exemplary embodiments disclosed herein. The present invention therefore is 
to be limited not by the specific exemplary embodiments disclosed herein 
but by all embodiments within the scope of the appended claims.