Information
-
Patent Grant
-
6307583
-
Patent Number
6,307,583
-
Date Filed
Wednesday, September 1, 199925 years ago
-
Date Issued
Tuesday, October 23, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Soltis; Lisa M.
- Croll; Mark W.
- Breh; Donald J.
-
CPC
-
US Classifications
Field of Search
US
- 347 217
- 400 218
- 400 219
- 400 235
- 400 2351
- 400 234
-
International Classifications
- B41J3324
- B41J3326
- B41J3352
- B41J3300
-
Abstract
A thermal printer that transfers print from a ribbon onto a moving web, and methods therefor, by dispensing ribbon from a supply spindle with one or more feed rollers rotating in a first direction, and winding the ribbon on a rewind spindle when dispensing ribbon from the supply spindle when printing. The dispensing direction of the ribbon is reversible before or after printing by rotating the one or more feed rollers in a second direction opposite the first direction to utilize ribbon more efficiently. The reversed ribbon is either rewound on the supply spindle or tensioned with a dancer arm.
Description
BACKGROUND OF THE INVENTION
The invention relates generally to thermal printers, and more particularly to thermal printers having reversible ribbons and methods therefor.
Thermal printers are known generally and used widely, for example to print variable information including lot codes, bar-codes, time and date, and other information on products and packaging, referred to herein as a web or substrate, in coding and marking operations. These printers comprise generally a thermal print head that transfers ink from a carrier, also known as a ribbon, disposed between the web and print head, which may be movable away from the ribbon when not printing. The ribbon is usually advanced, or dispensed, intermittently from a supply spindle to a rewind spindle, for example by an electrically or pneumatically driven feed roller or other known ribbon transfer means.
In some thermal printing operations, printing occurs while the web moves relative to the thermal printer, and thus it is necessary for the ribbon to move generally at the same speed as the web during ink transfer. A short time interval however is required to accelerate the ribbon from a stand-still to the web speed prior to printing. This time interval, or delay, depends generally on the speed of the web and also on the capacity of the ribbon transfer means, and results in only partial usage of the ribbon. More particularly, dispensed ribbon advanced beyond the print head while the ribbon accelerates up to the web speed prior to printing is unused, and thus wasted. Moreover, increased web speeds, which improve productivity, cause even greater ribbon waste since more time is required for the ribbon to accelerate up to the web speed. The ribbon is a costly consumable in coding and marking operations, and therefore it is desirable to utilize ribbon as efficiently as possible.
The present invention is drawn toward advancements in thermal printers.
An object of the invention is to provide novel thermal printers and methods therefor that overcome problems in the art.
Another object of the invention is to provide novel thermal printers and methods therefor that are reliable and economical.
Another object of the invention is to provide novel thermal printers and methods therefor that use ribbon more efficiently.
Another object of the invention is to provide novel thermal printers and methods therefor capable of reversing the direction that the ribbon is fed or dispensed.
A further object of the invention is to provide novel thermal printers and methods therefor that are operated electrically without the need for a compressed air supply.
Yet another object of the invention is to provide novel thermal printers and methods therefor that operate reliably in greasy printing environmental conditions.
A more particular object of the invention is to provide novel thermal printers that transfer print from a ribbon onto a moving web and methods therefor comprising generally dispensing the ribbon from a supply spindle with a feed roller rotating in a first direction, winding the ribbon on a rewind spindle when dispensing ribbon from the supply spindle, and reversing the ribbon dispensing direction before or after printing by rotating the feed roller in a second direction opposite the first direction to rewind unused ribbon.
These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a thermal printer ribbon cassette according to an exemplary embodiment of the invention.
FIG. 2
is a thermal printer print engine for use with the cassette of FIG.
1
.
FIG. 3
partial sectional view of an exemplary feed roller.
FIG. 4
is a thermal printer ribbon cassette according to an alternative embodiment of the invention.
FIG. 5
is a thermal printer print engine for use with the cassette of FIG.
4
.
DETAILED DESCRIPTION OF THE INVENTION
The thermal printers of the present invention comprise generally a supply spindle for dispensing ribbon therefrom, a rewind spindle for winding ribbon dispensed from the supply spindle, and a feed roller coupled to a bi-directional motor that rotatably drives the feed roller in first and second opposing directions. The ribbon is disposed at least partially about and frictionally engaged with the feed roller, which is rotatable to feed, or dispense, ribbon in first and second reversible directions. The ribbon is fed between the web and a thermal print head, which in some embodiments may be positioned away from the ribbon when not printing on the web.
When printing on a moving web, generally, the feed roller rotates in a first direction that dispenses ribbon from the supply spindle. As ribbon is dispensed from the supply spindle, ribbon is also wound about the rewind spindle. After printing on the web, the ribbon feed direction is reversed by rotating the feed roller in a second direction opposite the first direction. In other words, the ribbon is backed-up slightly by reversing its feed direction before or after each printing operation to eliminate or substantially reduce the amount of unused ribbon that is advanced past the print head, when the ribbon was accelerated up to the substrate speed, thereby eliminating or at least substantially reducing ribbon waste.
In one embodiment, generally, the ribbon is rewound on the supply spindle when its feed direction is reversed. In an alternative embodiment, however, ribbon slack is taken up by a pivotal dancer arm without rewinding ribbon on the supply spindle. The amount of ribbon that is backed-up, and in some embodiments rewound on the supply spindle, by reversing the feed wheel direction depends generally on the amount of ribbon that advances past the print head while accelerating the ribbon up to the same speed as the substrate. Ribbon usage and feed rates are measured accurately with an encoder, as is known generally.
In the exemplary embodiment of
FIG. 1
, the thermal printer comprises generally a supply spindle
10
for dispensing ribbon
2
therefrom, a rewind spindle
20
for winding ribbon dispensed from the supply spindle, and a first feed roller
30
. The ribbon
2
dispensed from the supply spindle
10
and wound about the rewind spindle
20
may be wound about corresponding plastic or cardboard cores, not shown in the drawings, disposed and retained frictionally about the supply and rewind spindles, as is known generally.
In
FIG. 1
, the ribbon
2
is disposed at least partially about and frictionally engaged with the first feed roller
30
, which is coupled to a bi-directional motor that rotates the feed roller
30
in first and second opposing directions to dispense ribbon from and wind ribbon on the supply spindle
10
, as discussed more fully below. The ribbon
2
is dispensed from the supply spindle
10
to and about an idler roller
4
, which is preferably positioned so that the ribbon
2
is wound about a substantial portion of the feed roller
30
, and in the exemplary embodiment approximately one-half, or a 180 degree circumferential portion thereof, thereby increasing surface contact therewith to lessen the possibility of slippage of the ribbon
2
relative thereto, which may be troublesome in some operational environments.
Also in
FIG. 1
, a second feed roller
40
is coupled preferably to the bi-directional motor, and the ribbon
2
is disposed at least partially thereabout and frictionally engaged therewith at least for dispensing the ribbon from the supply spindle, and in some embodiments for reversing the ribbon feed direction, as discussed more fully below. The second feed roller
40
also has associated therewith an idler roller
6
positioned so that the ribbon
2
is wound substantially about the second feed roller
40
to increase surface contact therewith, as discussed above in connection with the first feed roller
30
. In alternative embodiments of the invention, however, only one feed roller is required.
A rotary encoder is used generally to measure incremental ribbon travel information, which is used to determine the distance that the ribbon is reversed after the printing operation, thereby minimizing unused portions of the ribbon between printing operations. In the exemplary embodiment of
FIG. 1
, an encoded disk
170
is disposed about and rotates with the idler roller
6
, which is rotated by the ribbon
2
wrapped thereabout. The ribbon
2
preferably has a substantial wrap angle around the idler roller
6
to minimize slippage, thus providing an accurate measure of ribbon travel. A detector
172
is disposed adjacent the disk
170
to measure the rotation thereof, which is input to a controller, not shown but known generally, that controls the bi-directional motor and thus the one or more feed rollers. In alternative embodiments, the encoder disk may be disposed on the one of the feed rollers, or another idler roller. Other known means for measuring ribbon distance travel may be used alternatively.
In some printing environments, for example in greasy manufacturing environments, it is desirable to use both the first and second feed rollers to advance and rewind the ribbon, discussed above, whereas in other embodiments of the invention only one feed roller is sufficient.
FIG. 1
also illustrates, in phantom, a pressure roller
50
biased, for example by a spring, to move the ribbon
2
against the feed roller
30
to further increase frictional engagement therewith, as is known generally. The pressure roller
50
may be desirable on one or both of the feed rollers in printer embodiments intended for use in applications where ribbon slippage is problematic.
In the first exemplary embodiment, the bi-directional motor is coupled to the supply and rewind spindles
10
and
20
for rotating the supply and rewind spindles in first and second opposing directions along with the one or more feed rollers.
FIG. 2
illustrates, more particularly, a bi-directional motor
70
, for example an electric stepper motor, having a drive pulley
72
coupled to a drive belt
80
, which is coupled to a supply pulley
12
, a rewind pulley
22
, a feed pulley
32
and alternatively a second feed pulley
42
in embodiments that include a second feed roller. In other embodiments, the bi-directional motor may be an air motor.
The drive belt
80
is preferably a toothed drive belt, or a chain, and the one or more feed pulleys
32
and
42
and the drive pulley
72
are preferably cogged pulleys engageable with the toothed drive belt or chain to ensure a positive, non-slip drive. In the exemplary embodiment, the supply and rewind pulleys
12
and
14
are non-cogged rubber pulleys, or rollers, engageable with the toothed drive belt
80
, since non-slipping engagement thereof with the drive belt
80
is not generally required, as discussed further below. The supply spindle
10
is coupled to the supply pulley
12
, the rewind spindle
20
is coupled to the rewind pulley
22
, the feed roller
30
is coupled to the feed pulley
32
, and the second feed roller
40
is coupled to the second feed pulley
42
, for example by corresponding drive shafts
14
,
24
,
34
and
44
.
In the first exemplary embodiment, the thermal printer comprises a ribbon cassette
100
illustrated in
FIG. 1
removably coupleable to a print engine
200
illustrated in FIG.
2
. In
FIG. 1
, the supply spindle
10
, the rewind spindle
20
, the feed roller
30
and the second feed roller
40
are rotatably mounted on the ribbon cassette
100
. And in
FIG. 2
, the bi-directional motor
70
, the supply pulley
12
, the rewind pulley
22
, the feed pulley
32
, and the second feed pulley
42
are rotatably mounted on the print engine
200
. When the ribbon cassette
100
is coupled to the print engine
200
, the supply spindle
10
is coupled to the supply pulley
12
, the rewind spindle
20
is coupled to the rewind pulley
22
, the feed roller
30
is coupled to the feed pulley
32
, and the second feed roller
40
is coupled to the second feed pulley
42
, by means known generally. The ribbon cassette
100
and print engine
200
also include structure to facilitate the alignment, mounting and fastening thereof, as is known generally.
In
FIG. 1
, the supply and rewind spindles
10
and
20
and the feed rollers
30
and
40
each include one or more lugs or dogs
8
protruding from an axial end thereof. The dogs
8
are coupled to the corresponding pulleys
12
,
22
,
32
, and
42
by corresponding recessed drive members that accommodate the dogs when the cassette
100
is coupled to the print engine
200
. The recessed drive members, not shown in
FIG. 1
, are coupled to the corresponding pulleys by the drive shafts associated therewith, as is known generally and discussed further below.
In other embodiments, the thermal printer does not include a removable cassette, and is instead a single assembly. In this alternative non-removable ribbon cassette embodiment,
FIG. 1
is interpreted as a front side of the thermal printer and
FIG. 2
is interpreted as a back-side of the thermal printer. The supply spindle
10
is coupled directly to the supply pulley
12
, the rewind spindle
20
is coupled directly to the rewind pulley
22
, the feed roller
30
is coupled directly to the feed pulley
32
, and the second feed roller
40
is coupled directly to the second feed pulley
42
by the corresponding drive shafts
14
,
24
,
34
and
44
extending between the rear and front sides of the printer, without the lugs and slots.
In
FIG. 2
, the thermal printer further comprises a thermal print head
90
mounted on the print engine
200
for transferring ink from the ribbon onto the web during printing operations. The print head
90
of
FIG. 2
is viewed from a back-side of the print engine
200
, and is similar to the print head
90
of
FIG. 5
, which is viewed from a front -side of a print engine according to an alternative embodiment discussed further below. The thermal print head
90
is preferably movable toward and away from the ribbon, and in the exemplary embodiment of
FIG. 2
a rotary solenoid
106
mounted on the print engine is coupled to the thermal print head
90
by an actuator linkage
107
for this purpose. Alternatively the solenoid
106
may be a linear solenoid. In operation, the solenoid
106
moves the print head
90
toward the ribbon during printing operations and moves the print head
90
away from the ribbon when not printing.
FIG. 3
is a partial sectional view of a supply spindle
10
configured according to an exemplary embodiment of the invention. The supply spindle
10
has an outer drum
120
disposed generally concentrically about an inner shaft. A slip clutch
140
couples the outer drum
120
to a rotatable inner shaft portion
110
of the inner shaft, which is coupled to the bi-directional motor, and more particularly to the supply pulley as discussed above. The slip clutch
140
controls rotation of the outer drum
120
relative to the inner shaft portion
110
depending upon the relative rotational movement therebetween, as discussed more fully below. In the exemplary embodiment, the outer drum
120
includes a resilient member
122
or other means for frictionally engaging and retaining a ribbon core, not shown, thereabout.
A drag brake
130
couples the outer drum
120
to a fixed inner shaft portion
165
of the inner shaft, wherein the fixed inner shaft portion is aligned axially with the rotatable inner shaft portion. In the exemplary embodiment, the fixed inner shaft portion
165
is coupled to the ribbon cassette
100
. The drag brake
130
controls rotation of the outer drum
120
relative to the fixed inner shaft portion
165
depending upon the relative rotational movement therebetween, as discussed more fully below.
The drive belt
80
rotates the supply and rewind spindles
10
and
20
and the one or more feed wheels
30
and
40
in one of the first and second opposing directions, depending on the rotational direction of the bi-directional motor. The rotational speed of the supply and rewind spindles, however, are generally different than the rotational speed of the feed wheel, which is constant, or fixed. More particularly, the rotational speed of the supply and rewind spindles
10
and
20
varies depending on the diameter of the ribbon wound thereabout. Generally, the diameter of the ribbon on the supply spindle decreases and the diameter of the ribbon on the rewind spindle increases during operation of the printer, although the ribbon diameter of the supply spindle may temporarily increase slightly when the ribbon feed direction is reversed and ribbon is wound thereabout, as discussed above.
In the supply spindle
10
, the drag brake
130
generally provides a controlled amount of drag on the outer drum
120
about the fixed inner shaft portion
165
as the outer drum
120
rotates in a direction that dispenses ribbon from the supply spindle
10
, thereby providing a controlled amount of tension on the ribbon dispensed from the supply spindle. The slip clutch
140
generally allows a controlled amount of slippage of the outer drum
120
relative to the rotatable inner shaft portion
110
when the supply spindle
10
rotates in a direction that winds ribbon thereabout, thereby providing a controlled amount of tension on the ribbon wound about the supply spindle.
In the exemplary embodiment of
FIG. 3
, the drag brake
130
is a wrap-around spring having a first end portion
132
frictionally engaged with the fixed inner shaft portion
165
and a second end portion
134
frictionally engaged with the outer drum
120
when the outer drum
120
rotates about the fixed inner shaft portion
165
in a direction that dispenses ribbon from the supply spindle
10
, thereby providing the controlled amount of frictional drag between the fixed inner shaft portion and the outer drum. The slip clutch
140
is also a wrap-around spring having a first end portion
142
frictionally engaged with the rotatable inner shaft portion
110
and a second end portion
144
frictionally engaged with the outer drum
120
when the outer drum
120
rotates about the inner shaft portion
110
in a direction that winds ribbon on the supply spindle
10
, thereby providing the controlled amount of frictional slippage between the rotatable inner shaft portion and the outer drum.
Alternatively, the drag brake and slip clutch may comprise corresponding torsional springs instead of wrap-around springs. The torsional springs each have generally an end portion coupled to the outer drum, whereby a portion of the torsional spring is wound between the corresponding fixed or rotatable inner shaft portions and outer drum in a direction that engages the inner shaft to provide the desired drag or slippage therebetween, depending on the rotational direction of the outer drum.
In
FIG. 3
, the supply spindle
10
preferably includes a one-way clutch
150
coupling the drag brake
130
to the fixed inner shaft portion
165
. The one-way clutch
150
operates to disengage the drag brake
130
when the outer drum
120
rotates about the fixed inner shaft portion
165
in a direction that winds ribbon on the supply spindle
10
. The one-way clutch
150
thus eliminates any drag created by the drag brake
130
when the outer drum
120
rotates in a direction that winds ribbon about the supply spindle. The one-way clutch
150
also reduces the load on the bi-directional motor thus permitting use of a smaller, less costly motor.
The rewind spindle
20
is configured and operates generally the same as the supply spindle
10
, as illustrated in FIG.
3
and discussed above. More particularly, the drag brake of the rewind spindle generally provides a controlled amount of drag on the outer drum thereof when the rewind spindle rotates in a direction that dispenses ribbon therefrom, thereby providing a controlled amount of tension on the ribbon. The slip clutch of the rewind spindle generally allows the outer drum thereof to slip in a controlled manner relative to the rotatable inner shaft when the rewind spindle rotates in a direction that winds ribbon thereabout, thereby providing a controlled amount of tension on the ribbon. The rewind spindle also preferably includes a one-way clutch that couples the drag brake thereof to the fixed inner shaft for disengaging the drag brake when the outer drum rotates in a direction that winds ribbon on the rewind spindle, as discussed above in connection with the supply spindle.
FIG. 4
is another exemplary embodiment of the thermal printer comprising generally a supply spindle
10
for dispensing ribbon
2
therefrom, a rewind spindle
20
for winding ribbon dispensed from the supply spindle, and a first feed roller
30
. The ribbon
2
dispensed from the supply spindle
10
and wound about the rewind spindle
20
may also be disposed generally about corresponding plastic or cardboard cores disposed thereabout, as discussed above.
In
FIG. 4
, the ribbon
2
is dispensed from the supply spindle
10
to and about an idler roller
3
and then about at least one dancer roller
182
of a dancer arm
180
biased by a spring member
185
to pivot about a pivot
183
. In the exemplary embodiment, the ribbon
2
is also disposed about a second idler roller
5
, about a second dancer roller
184
of the dancer arm
180
, and then about a third idler roller
7
. The dancer arm
180
is pivotal about the pivot
183
to control slack, and more particularly to maintain tension, in the ribbon
2
, during operation of the thermal printer, as discussed further below.
In
FIG. 4
, the ribbon
2
is fed from the third idler roller
7
to a fourth idler roller
9
and then at least partially about the feed wheel
30
where it is engaged frictionally with the assistance of a pressure roller
50
biased into engagement with the feed roller
30
by a spring member
52
. The feed roller
30
of
FIG. 4
may be configured alternatively without the pressure roller
50
, for example with one or more additional idler rollers that dispose the ribbon about a substantial portion of the feed roller
30
as in the embodiment of FIG.
1
.
In
FIG. 4
, the feed roller
30
is coupled to the rewind spindle
20
by a drive belt
60
, which rotates the rewind spindle
20
in the same direction that the feed wheel
30
is driven by the bi-directional motor. The drive belt
60
however is capable of slipping relative to the rewind spindle
20
to permit the rewind spindle to vary its speed as the ribbon diameter thereof changes. The ribbon wound about the rewind spindle
20
thus has a controlled amount of tension applied thereto as it slips relative to the drive belt
60
.
Also in
FIG. 4
, the supply spindle
10
has coupled thereto a drag brake that provides a controlled amount of drag on the supply spindle
10
as ribbon is dispensed therefrom, thereby maintaining a controlled amount of tension on the ribbon dispensed from the supply spindle. The drag brake in
FIG. 4
is a resilient belt
62
disposed about and frictionally engageable with the supply spindle
10
. The resilient belt
62
includes a spring member
63
connected thereto for providing resiliency. The drag applied by the resilient belt
62
on the supply spindle
10
varies with the generally decreasing diameter of the ribbon thereon, and depends generally on the pivotal position of the dancer arm
180
to which opposing ends of the resilient belt are connected, as is known generally. Alternatively, the drag on the supply spindle
10
may be provided by other known drag brakes, including those discussed hereinabove in connection with the embodiment of FIG.
1
.
In
FIG. 4
, the ribbon dispensing direction is reversed by rotating the feed roller
30
and rewind spindle
20
in a direction that dispenses the ribbon
2
from the rewind spindle
20
, counter-clockwise in FIG.
4
. As the ribbon
2
is dispensed from the rewind spindle
20
, the dancer arm
180
is pivoted by the spring member
185
in a direction that takes up slack in the ribbon
2
, clockwise in FIG.
4
. Thus configured, it is not necessary to rewind ribbon on the supply spindle
10
when dispensing ribbon from the rewind spindle
20
, as in the embodiment of
FIG. 1
, since the dancer arm
180
maintains tension on the ribbon
2
.
The dancer arm
180
has a limited ability to take compensate for slack in the ribbon
2
in comparison to the reversibly rotatably supply spindle
10
in
FIG. 1
, which can rewind an unlimited amount of ribbon thereabout. The dancer arm
180
of the embodiment of
FIG. 4
, however, permits sufficient rewinding of ribbon advanced beyond the print head during acceleration of the ribbon up to the web speed to more completely utilize the ribbon. The amount of slack taken up by the dancer arm
180
depends generally on the extent of the pivotal displacement thereof, and on the number of dancer rollers thereon.
In the second exemplary embodiment, the thermal printer comprises a ribbon cassette
101
, illustrated in
FIG. 4
, removably coupleable to a print engine
201
illustrated in FIG.
5
. In
FIG. 4
, the feed roller
30
is rotatably mounted on the ribbon cassette
101
, and the bi-directional motor
70
, shown in phantom lines in
FIG. 5
, is mounted on a back-side of the print engine
201
. In
FIG. 5
, the bi-directional motor
70
is coupled to a drive member
74
on a front side of the print engine
201
. The drive member
74
has one or more dogs
8
protruding from an axial end thereof, which are disposed in corresponding recesses
35
on an end of the feed roller
30
as illustrated in
FIG. 4
when the ribbon cassette
101
is coupled to the print engine
201
. Alternatively, the recesses may be disposed on the drive member, and the dogs may be disposed on the feed roller, as discussed above in connection with the embodiment of FIG.
1
. The ribbon cassette
101
and print engine
201
also include structure to facilitate alignment, mounting and fastening thereof, as is known generally.
In
FIG. 5
, the thermal printer further comprises a thermal print head
90
mounted on the print engine
201
for transferring ink from the ribbon onto the web during printing operations. The thermal print head
90
is preferably movable toward and away from the ribbon, and in the exemplary embodiment of
FIG. 5
a linear solenoid
108
mounted on the print engine
201
is coupled to the thermal print head
90
by an actuator linkage
109
for this purpose. Alternatively, the solenoid
108
may be a rotary solenoid. In operation, the solenoid
108
moves the print head
90
toward the ribbon during printing operations and moves the print head
90
away from the ribbon when not printing.
While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific exemplary embodiments herein. The invention is therefore to be limited not by the exemplary embodiments herein, but by all embodiments within the scope and spirit of the appended claims.
Claims
- 1. A thermal printer for transferring print from a ribbon onto a web, comprising:a supply spindle; a rewind spindle; the ribbon wound partially about the supply spindle and the rewind spindle; first and second feed rollers, the ribbon disposed at least partially about and frictionally engaged with the first and second feed rollers; a bi-directional motor coupled to the first and second feed rollers, the bi-directional motor rotates at least one of the first and second feed rollers in first and second opposing directions, the bi-directional motor further coupled to the supply and rewind spindles for rotating the supply and rewind spindles in first and second opposing directions.
- 2. A thermal printer for transferring print from a ribbon onto a web, comprising:a supply spindle; a rewind spindle; the ribbon wound partially about the supply spindle and the rewind spindle; a feed roller, the ribbon disposed at least partially about and frictionally engaged with the feed roller; a bi-directional motor coupled to the feed roller, the bi-directional motor rotates the feed roller in first and second opposing directions, the bi-directional motor further coupled to the supply and rewind spindles for rotating the supply and rewind spindles in first and second opposing directions, wherein the bi-directional motor is a stepper motor having a drive pulley coupled to a drive belt, the supply spindle coupled to the drive belt by a supply pulley, the rewind spindle coupled to the drive belt by a rewind pulley, and the feed roller coupled to the drive belt by a feed pulley.
- 3. The thermal printer of claim 2a ribbon cassette removably coupleable to a print engine having the bi-directional motor mounted thereon, the supply pulley, the rewind pulley, and the feed pulley rotatably mounted on the print engine, the supply spindle, the rewind spindle, and the feed pulley rotatably mounted on the ribbon cassette, the supply spindle coupled to the supply pulley, the rewind spindle coupled to the rewind pulley, and the feed roller coupled to the feed pulley when the print cassette is coupled to the print engine.
- 4. The thermal printer of claim 3, the drive belt is a toothed drive belt, the drive pulley and the feed pulley are cogged pulleys.
- 5. The thermal printer of claim 3, thermal print head mounted on the print engine, the thermal print head movable toward and away from the ribbon, a rotary solenoid mounted on the print engine and coupled to the thermal print head, the rotary solenoid actuatable to move the thermal print head toward and away from the ribbon.
- 6. A thermal printer for transferring print from a ribbon onto a web, comprising:a supply spindle; a rewind spindle, the ribbon wound partially about the supply spindle and the rewind spindle; a feed roller, the ribbon disposed at least partially about and frictionally engaged with the feed roller; a bi-directional motor coupled to the feed roller, the bi-directional motor rotates the feed roller in first and second opposing directions, the bi-directional motor further coupled to the supply and rewind spindles for rotating the supply and rewind spindles in first and second opposing directions, wherein the supply spindle has an outer drum disposed about an inner shaft, a drag brake couples the outer drum to a fixed portion of the inner shaft and a slip clutch couples the outer drum to a rotatable portion of the inner shaft coupled to the bi-directional motor, the drag brake provides drag on the outer drum when the supply spindle rotates in a direction that dispenses ribbon therefrom, and the slip clutch allows the outer drum to slip relative to the inner shaft when the supply spindle rotates in a direction that winds ribbon thereabout, and wherein the rewind spindle has an outer drum disposed about an inner shaft, a drag brake couples the outer drum to a fixed portion of the inner shaft and a slip clutch couples the outer drum to a rotatable portion of the inner shaft coupled to the bi-directional motor, the slip clutch allows the outer drum to slip relative to the inner shaft when the rewind spindle rotates in a direction that winds ribbon thereabout, and the drag brake provides drag on the outer drum when the rewind spindle rotates in a direction that dispense ribbon therefrom.
- 7. The thermal printer of claim 6,the supply spindle includes a one-way clutch coupling the drag brake to the inner shaft, the one-way clutch disengages the drag brake when the supply spindle rotates in a direction that winds ribbon thereabout, and the rewind spindle includes a one-way clutch coupling the drag brake to the inner shaft, the one-way clutch disengages the drag brake when the rewind spindle rotates in a direction that winds ribbon thereabout.
- 8. The thermal printer of claim 6, the drag brake of the supply and rewind spindles are wrap-around springs having a first portion engageable with the inner shafts thereof and a second portion engageable with the outer drums thereof to provide a controlled amount of drag therebetween, and the slip clutches of the supply and rewind spindles are wrap-around springs having a first end portion engagable with the inner shafts thereof and a second portion engageable with the outer drums thereof to provide a controlled amount of slippage therebetween.
- 9. The thermal printer of claim 6, a second feed roller, the ribbon disposed at least partially about and frictionally engaged with the second feed roller, the bi-directional motor coupled to the second feed roller, a rotary encoder coupled to the ribbon.
- 10. The thermal printer of claim 9, the bi-directional motor is a stepper motor having a drive pulley coupled to a drive belt, the supply spindle coupled to the drive belt by a supply pulley, the rewind spindle coupled to the drive belt by a rewind pulley, the feed roller coupled to the drive belt by a feed pulley, and the second feed roller coupled to the drive belt by a second feed pulley.
- 11. The thermal printer of claim 10a ribbon cassette removably coupleable to a print engine having the bi-directional motor mounted thereon, the supply pulley, the rewind pulley, the feed pulley, and the second feed pulley rotatably mounted on the print engine, the supply spindle, the rewind spindle, the feed roller, and the second feed roller rotatably mounted on the ribbon cassette, the supply spindle coupled to the supply pulley, the rewind spindle coupled to the rewind pulley, the feed roller coupled to the feed pulley, and the second feed roller coupled to the second feed pulley when the print cassette is coupled to the print engine.
- 12. A thermal printer for transferring print from a ribbon onto a web, comprising:a supply spindle; a rewind spindle, the ribbon wound partially about the supply spindle and the rewind spindle; a feed roller, the ribbon disposed at least partially about and frictionally engaged with the feed roller; a bi-directional motor coupled to the feed roller, the bi-directional motor rotates the feed roller in first and second opposing directions; and a pivotal dancer arm having a dancer roller disposed between the supply spindle and the feed roller, the ribbon disposed at least partially about the dancer roller, the dancer arm biased to maintain tension on the ribbon.
- 13. The thermal printer of claim 12, the feed roller coupled to the rewind spindle by a drive belt that rotates the rewind spindle, and a drag brake coupled to the supply spindle, the drag brake drags the supply spindle as ribbon is dispensed therefrom.
- 14. The thermal printer of claim 13, a ribbon cassette removably coupleable to a print engine having the bi-directional motor mounted thereon, the supply spindle, the rewind spindle, and the feed roller rotatably mounted on the ribbon cassette, the feed roller coupled to the bi-directional motor when the ribbon cassette is coupled to the print engine.
- 15. The thermal printer of claim 14, a thermal print head mounted on the print engine, the thermal print head movable and away from the ribbon, a linear solenoid mounted on the print engine and coupled to the thermal print head, the linear solenoid actuatable to move the thermal print head toward and away from the ribbon.
- 16. A method for a thermal printer that transfers print from a ribbon onto a moving web, comprising:dispensing the ribbon from a supply spindle by frictionally engaging the ribbon with a feed roller rotating in a first direction; winding the ribbon on a rewind spindle when dispensing ribbon from the supply spindle; and reversing the dispensing direction of the ribbon by frictionally engaging the ribbon with the feed roller rotating in a second direction opposite tile first direction; and accelerating the ribbon dispensed from the supply spindle to a speed of the moving web, and transferring ink from the ribbon onto the web when the ribbon speed is substantially the same as the web speed.
- 17. The method of claim 16, dispensing the ribbon from the rewind spindle and winding the ribbon on the supply spindle when reversing the ribbon dispensing direction.
- 18. The method of claim 17, rotating the supply spindle, the rewind spindle and the feed roller in first and second opposing directions with a drive belt coupled to a bi-directional motor, dragging the supply spindle when dispensing ribbon therefrom and slipping the rewind spindle when winding ribbon thereon, and dragging the rewind spindle when dispensing ribbon therefrom and slipping the supply spindle when winding ribbon thereon.
- 19. The method of claim 18, dispensing the ribbon by frictionally engaging the ribbon with a second feed roller rotated by the drive belt coupled to the bi-directional motor.
- 20. The method of claim 16, moving a thermal print head toward the ribbon when printing on the web, and moving the thermal print head away from the ribbon when not printing on the web.
- 21. A method for a thermal printer that transfers print from a ribbon onto a moving web, comprising:dispensing the ribbon from a supply spindle by frictionally engaging the ribbon with a feed roller rotating in a first direction; winding the ribbon on a rewind spindle when dispensing ribbon from the supple spindle; and reversing the dispensing direction of the ribbon by frictionally engaging the ribbon with the feed roller rotating in a second direction opposite the first direction; and supplying the ribbon from the rewind spindle when reversing the ribbon dispensing direction, and taking up slack in the ribbon with a pivotal dancer arm coupled thereto when reversing the ribbon dispensing direction.
- 22. The method of claim 21, rotating the rewind spindle with a drive belt coupled to the first feed roller, dragging the supply spindle when dispensing ribbon therefrom, and slipping the rewind spindle when winding ribbon thereon.
US Referenced Citations (9)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0 734 876 A3 |
Oct 1996 |
EP |
2 289 444 A |
Nov 1995 |
GB |
PCTGB9600875 |
Apr 1996 |
GB |
60-63187 |
Apr 1985 |
JP |