Label printer and label strip feed mechanism therefor

A label printer for receiving a continuous strip of labels on a backing strip from a label supply and for passing the labels between a thermal first head and a platen roller. A motor connected with the platen roller rotates the platen roller. A peeling rod located past the thermal head in the path of the backing strip about which the strip is sharply deflected for separating the labels from the backing strip. A rotatable presser roller opposite the platen roller and past the peeling rod for pressing the backing strip with the labels now removed against the platen roller, whereby the label strip is driven by the platen roller past the thermal head and the backing strip is driven by the rotation of the platen roller and the cooperating rotation of the presser roll again past the platen roller. The presser roll is supported by a support having positioning notches for selectively positioning the presser roll either engaging the platen roller or spaced from the platen roller, the latter position permitting threading of the strip member between those rollers. A spring normally urges the presser roller toward the platen roller. When the presser roller is supported in the support, it is held against the spring.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The present invention relates to a printer, and more particularly to an 
electronic printer used for printing a strip of labels temporarily 
attached on a continuous backing strip. The printer equipped with a 
presser roller that presses against a platen roller for feeding out a 
backing strip after labels that were removably attached at regular 
intervals to the backing strip have been peeled therefrom. 
This invention further relates to a printer feed mechanism which issues 
labels by causing labels temporarily attached at regular intervals to a 
backing strip to be printed by a platen roller and a thermal head and to 
then be peeled off the backing strip by a label peeler. 
Description of the Prior Art 
FIG. 5 shows one prior art electronic printer having a printing mechanism 
comprising a thermal head 1 and a cooperating platen roller 2. An 
unprinted, continuous label strip 7 consisting of a backing strip 8 with a 
plurality of labels 9 temporarily attached thereon, e.g. by an adhesive, 
is held between the thermal head 1 and the platen roller 2 so that the 
head prints the labels as the continuous label strip 7 is fed past it. 
After the labels are printed, the continuous label strip 7 is forwarded to 
a backing strip deflecting peeler rod 3 located past the printing 
mechanism in the backing strip path, and the rod 3 defines label peeling 
means. The backing strip 8 is turned sharply away from its surface 
carrying the labels at the peeler rod 3 which causes the stiffer labels 9 
to peel off the backing strip. Only the turned back backing strip 8 is 
passed between a pair of feed rollers 4, 6 that are located below the 
platen roller 2 and that are rotated so as to feed the backing strip 8 
downward. The fed out backing strip is either cut to appropriate lengths 
or is simply allowed to trail downward without being rolled. 
The feed roller 6 is built into a detachable unit 5 which can be inserted 
into and removed from the body of the electronic printer. Before the 
electronic printer can be used, the backing strip 8 has to be passed 
between the feed rollers 4, 6. For this, it is necessary to draw the 
backing strip 8 to be below the feed roller 4 disposed inside the printer 
body, and to then attach the detachable unit 5 to the printer body in such 
manner that its feed roller 6 presses against the feed roller 4 with the 
backing strip 8 sandwiched between the two feed rollers. 
The need to attach and detach the separate unit 5 including the feed roller 
6 has made this prior art electronic printer troublesome to use. Moreover, 
since the backing strip feed rollers 4, 6 are provided separately of the 
platen roller 2 and have to be driven by a separate motor, this prior art 
electronic printer is large in size. 
In a second prior art printer with feed mechanism shown in FIG. 8, a 
backing strip 107 having labels 101 temporarily attached thereon at 
regular internals is unwound from a supply reel 103 and is fed between a 
platen roller 104 and a thermal head 105 where the labels are printed. 
After that, the backing strip 102 is fed to and turned back around a 
peeler rod 106 at which the labels 101 are peeled off and are issued to 
the exterior of the printer. The labels 101 peeled off the backing strip 
102 are either attached to the objects to be labeled (not shown) by hand 
or are supplied to a label attached (not shown). After wrapping over the 
rod 106, the backing strip 102 is either fed out continuously or is cut 
off at appropriate lengths. 
In this conventional printer feed mechanism, the platen roller 104 is 
rotated by a stepping motor 107 which operates through a gear mechanism 
108, 109 to convey the portion of the backing strip 102 held between the 
platen roller 104 and the thermal head 105, to unwind the backing strip 
102 from the supply reel 103 and forward it to the peeler rod 106. After 
it passes over the peeler rod 106, the leading end of the backing strip 
102 passes between a drive roller 110 and a presser roller 111 driven by 
the drive roller 110. The rotation of the drive roller 110 ensures that no 
slack develops in the backing strip 102 as it is fed over and turned back 
by the peeler rod 106. Since the labels 101 are stiffer than the backing 
strip 102, they peel off the backing strip 102 at the time that the 
backing strip 102 is turned back. 
In recent years, there has been increasing emphasis on making products 
lighter and more compact, The above described prior art printer feed 
mechanism runs counter to this trend, however, since it requires as a 
power source for feeding labels not only the stepping motor 107 but also a 
motor for driving the drive roller 110. This makes the printer heavy and 
difficult to reduce in size. 
SUMMARY OF THE INVENTION 
The embodiments of the present invention were developed in light of the 
foregoing problems. The primary object of the invention is to provide an 
electronic printer with a simplified feed roller mechanism that can be 
manufactured at low cost. 
Another object of the invention is to provide a printer feed mechanism 
which uses only a stepping motor as a power source for feeding labels and 
which also enables reduction in the number of feed rollers, thus making it 
possible to realize a light weight and compact printer. 
The present invention provides a printer having a supply shaft from which a 
continuous strip consisting of a backing strip having labels temporarily 
attached thereon is supplied by winding the continuous strip onto the 
supply shaft and then later unwinding the strip from that shaft. A thermal 
head is provided on the feed path for the continuous strip. A platen 
roller is disposed opposite the thermal head. Label peeling means are 
provided on the feed path downstream of the thermal head for peeling 
labels from the continuous backing strip. A backing strip deflecting rod, 
or blade, or the like deflecting means may be used. Rotary presser means 
are positioned opposite the platen roller on the feed path of the backing 
strip downstream of the peeling means. Retaining means retain the rotary 
presser means. Support means support the rotary presser means. Urging 
means press the rotary presser means toward the platen roller. The support 
means are formed with means, e.g. at least one notch, for supporting the 
rotary presser means against the bias of the urging means to leave a space 
between the platen roller and the presser means. The rotary presser means 
are driven to rotate by the rotation of the platen roller. The presser 
means may be a separate roll. 
When the electronic printer is to be set up for operation, the continuous 
label strip is passed between the thermal head and the platen roller to be 
held therebetween. The backing strip alone is turned back at the peeling 
means which are located downstream of the thermal head, and the turned 
back backing strip is drawn downward toward the platen roller. The rotary 
presser means, e.g. a presser roller is pulled away from the platen 
roller, against the force of the urging means, and is engaged in one of 
the notches of the presser roller support means so as to establish a gap 
between the presser roller and the platen roller. The backing strip is 
passed through the gap. The presser roller is then moved to another notch 
of the presser roller support means so as to return the presser roller 
toward the platen roller and to permit the urging means to cause the 
presser roller to press against the platen roller with the backing strip 
caught between the presser roller and the platen roller. 
After the backing sheet has been set in the foregoing manner, the platen 
roller is rotated by a motor. This continuously draws unprinted label 
strip off the supply shaft and feeds it to the thermal head. The thermal 
head and the platen roller print prescribed information on the labels fed 
between them. The printed labels are then fed out further downstream of 
the label peeling means, where the labels are peeled off the backing 
strip. Only the backing strip is turned back around the peeling means. The 
turned back backing strip, which is caught between the platen roller and 
the presser roller, is fed downward by the rotation of the platen roller 
and by the rotation of the presser roller driven by the platen roller. 
A second embodiment of a printer feed mechanism for a label printer passes 
a backing strip having labels temporarily attached thereon between a 
thermal head and a platen roller which constitute a printing section for 
printing the labels. The backing strip is forwarded from the printing 
section toward peeling means by rotation of the platen roller. The backing 
strip is turned back by the peeling means for peeling the printed labels 
off the backing strip. The printer feed mechanism comprises a presser 
roller which is located opposite the platen roller for pressing against 
the platen roller and for being rotated thereby. The backing strip which 
is fed out from the printing section and is turned back by the peeling 
means is passed between and fed by the platen roller and the presser 
roller. 
The presser roller presses onto the platen roller and is driven to rotate 
by the rotation of the platen roller. The backing strip being fed out from 
the printing section passes by the peeling means to move between the 
platen roller and the presser roller. As a result, when the platen roller 
is rotated, the part of the backing strip whose labels have been printed 
at the printing section is fed to the peeling means at a prescribed 
feeding speed. At the same time, the presser roller pressed against the 
platen roller through the backing strip is rotated by the rotation of the 
platen roller so as to feed the backing sheet, which is fed out from the 
printing section, at the same prescribed feeding speed. Since the backing 
strip fed out from the printing section is therefore fed to and turned 
back by the peeling means without developing any slack, the labels can be 
reliably peeled off the backing strip. 
The printer feed mechanism according to this invention thus requires only 
the stepping motor as a power source for feeding labels. It does not 
require a drive roller and a motor for driving a drive roller, as is 
necessary in prior art label printer feed mechanisms. It therefore enables 
the printer in which it used to be made light and compact. 
Other features and advantages of the present invention will become apparent 
from the following description of the invention which refers to the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A first embodiment of the present invention is now explained with reference 
to FIGS. 1 to 4. FIG. 1 schematically shows the overall configuration of 
the electronic printer. The printer includes a supply shaft on which a 
continuous label strip 14 is wound, a thermal print head 32, a platen 
roller 34 disposed opposite the thermal head 32, a peeler rod 36 
positioned beyond the thermal head 32, and a presser roller 50 positioned 
below the peeler rod 36 and movable for pressing against the platen roller 
34. 
The continuous strip 14 (or 20) is comprised of a backing strip 42 and a 
plurality of labels 16 (or 22). The labels 16 (or 22) are coated on one 
side with an adhesive and are temporarily attached to the backing strip 42 
at regular intervals. When the continuous strip 14 is wound on the supply 
shaft 10 with the labels 16 facing inward, the strip 14 is paid off for 
printing in the direction indicated by the arrow 18. On the other hand, 
when the continuous strip 20 is wound on the supply shaft 10 with the 
labels 22 facing outward, it is paid off for printing in the direction 
indicated by the arrow 24. The following explanation is based on the 
assumption that the continuous strip 14 is wound with the labels facing 
inward. 
The thermal head 32 and the platen roller 34 constitute a printing section. 
The platen roller 34 is driven to rotate by a motor 35 via a gear 96 
provided on the shaft of the motor 35, an intermediate gear 94 and a gear 
92 provided on the shaft of the platen roller 34. 
In the illustrated embodiment, the peeling means for turning back the 
backing strip 42 is the peeler rod 36 located past the head 32. However, 
the peeling means is not limited to this arrangement, and the peeling 
means may instead comprise a member formed with a sharp or angular edge 
about which the backing strip is deflected. 
FIG. 2 is an enlarged partial view showing how the presser roller 50 is 
pressed onto the platen roller 34 for grasping the backing strip 42. As 
shown in FIGS. 2 and 3, the presser roller mechanism is comprised of the 
presser roller 50, the shaft 54 of the presser roller 50, a retaining arm 
or bracket of generally U-shape and comprised of long arm 70 and short 
arms 72 for retaining the presser roller, a pair of support frames 60 for 
supporting the presser roller 50, and a pair of springs 90 attached to the 
opposite ends of the long arm 70. 
The presser roller 50 is formed of an elastic material such as resin or 
rubber. A plurality of small grooves 52 are formed around its periphery 
spaced from one another along the longitudinal direction of the presser 
roller 50. The presser roller 50 can be rotated in either direction, 
forward or reverse. 
The lower edge of the long arm 70 of the retaining bracket forms a cutter 
for cutting the backing strip 42 that has passed between the platen roller 
34 and the presser roller 50. Each short arm 72 of the bracket is fixed at 
one end to one end of the long arm 70 and at its other end to the shaft 54 
of the presser roller 50. The long arm 70 and the short arms 72 of the 
bracket can be formed separately or integrally with each other. 
Each spring 90 is attached at one end to a lug 82 provided on a side plate 
80 of the electronic printer body and at the other to one end of the long 
arm 70. The two springs 90 cooperate as urging means to urge the presser 
roller 50 toward the platen roller 34. 
FIG. 3 shows a side view of one of the support frames 60. The support 
frames 60 are built into and engage the side plates 80. As shown in FIG. 
3, the support frames 60 are formed with notches 62, 64 for enabling the 
shaft 54 of the presser roller 50 to be switched between two support 
positions. The notch 62 positions the presser roller 50 to press against 
the platen roller 34, with the backing strip 42 caught between the two 
rollers. The notch 64 positions the presser roller 50 to establish a gap 
for passage of the backing strip 42 between the presser roller 50 and the 
platen roller 34 when the printer is being set up for operation. The 
distance between the notch 62 and 64 need only be large enough to 
establish a gap for enabling easy passage of the backing strip 42 between 
the platen roller 34 and the presser roller 50. The depth of the notches 
62 should be adequate for retaining the shaft 54 of the platen roller 34. 
FIG. 4 is a side view of another example of a support frame 84. The support 
frame 84 has a notch 85 for retaining the shaft 54 and two notches 87, 88 
for retaining the retaining bracket arms 70, 72. When the presser roller 
50 is pressed against the platen roller 34, the presser roller shaft 54 is 
positioned at one end 85a of the notch 85 and the long arm 70 of the 
retaining bracket is retained in the notch 87. When the presser roller 50 
is separated from the platen roller 34, the presser roller shaft 54 is 
positioned at the other end 85b of the notch 85 and the long arm 70 of the 
retaining bracket is moved to and retained in the notch 88. 
The length of the protrusion 86 between the notch 85 and the notch 87 is 
based on the length of the short arms 72 of the retaining bracket. 
The operation of the first embodiment of the invention is now explained. 
During initial setup, the thermal head 32 is released from the platen 
roller 34 to establish a gap between them. The long arm 70 of the 
retaining bracket to which the presser roller 50 is attached is then 
pulled forward in FIGS. 1 and 2 against the force of the springs 90 for 
separating the presser roller 50 from the platen roller 34 and retaining 
the shaft 54 of the platen roller 34 in the notches 64 formed in the 
support frames 60 at positions more distant from the platen roller. This 
establishes a gap between the platen roller 34 and the presser roller 50. 
Next, the continuous strip 14 which is wound on the supply shaft 10 is paid 
out by hand and passed through the gap between the thermal head 32 and the 
platen roller 34. The continuous strip 14 is then paid out further and the 
backing strip 42 is turned back at the peeler rod 36 and is passed through 
the gap between the platen roller 34 and the presser roller 50. 
Following this, the thermal head 32 is returned to its position nearer the 
platen roller 34 so as to catch the continuous strip 14 between the 
thermal head 32 and the platen roller 34, and the presser roller shaft 54 
is moved from the notch 64 to the notch 62 nearer to the platen roller so 
as to press the presser roller 50 against the platen roller 34 and clamp 
the backing strip 42. 
After these preparations, the motor 35 is started, which rotates the platen 
roller 34 via the intermediate gear 94. The resulting rotation of the 
platen roller 34 feeds the continuous strip 14 through the printing 
section comprised of the thermal head 32 and the platen roller 34 so that 
the labels 16 are printed in the prescribed manner. The printed labels 40 
are peeled off by the peeler rod 36. The backing strip 42, now stripped of 
the printed labels 40, is held between the platen roller 34 and the 
presser roller 50 and is thereby further fed along a downstream backing 
strip feed path. 
Since the invention provides a simple mechanism for feeding out backing 
strip after the printed labels have been peeled off, the printer can be 
made compact and low in cost. 
A second preferred embodiment of the printer feed mechanism according to 
the present invention is shown in FIG. 6. The printer is adapted to issue 
printed labels by printing required information on labels 122 which are 
temporarily attached to a backing strip 120 and then peeling the printed 
labels 122 off the backing strip 120. For enabling this operation, the 
printer is equipped with a supply reel 124 for holding a label strip roll 
comprised of a continuous backing strip 120 having labels 122 temporarily 
attached at regular intervals thereon, a printing section 135 for printing 
the labels 122, a peeling section 137 for peeling the labels 122 printed 
by the printing section 135 off the backing strip 120, and a feed 
mechanism for feeding the backing strip 120 along a prescribed feed path. 
In FIGS. 6 and 7, the printing section 135 includes a platen roller 128 
having a rotary shaft 130 which is rotatably supported at opposite ends by 
a pair of vertically disposed support plates 132 which mount the platen 
roller 128 horizontally inside the printer body 126. A thermal head 134 is 
mounted directly above the platen roller 128 and applies a prescribed 
amount of pressure thereon. The backing strip 120 unwound from the supply 
reel 124 is held between the platen roller 128 and the thermal head 134 
for printing the labels 122 as required. 
The peeling section 137 is comprised of a peeler rod 136 which is fixed at 
its opposite ends to the support plates 132 and is positioned horizontally 
near the downstream end of the printing section 135. The feed direction of 
the portion of the backing strip 120 whose labels have been printed by the 
printing section 135 is turned back by the peeler rod 136. This causes the 
labels 122, which are stiffer than the backing strip 120, to be peeled off 
the backing strip 120 when the backing strip 120 is turned back at the 
peeler rod 136. 
The feed mechanism for feeding the backing strip 120 along the feed path is 
now explained. 
A gear 138 fitted on one end of the rotary shaft 130 of the platen roller 
128 is linked with a gear 146 of a stepping motor 144 through first and 
second gears 140, 142. A presser roller 148 has a rotary shaft 150 with 
opposite ends that pass through elongate holes 152 formed in the support 
plates 132, where they are supported by the opposite ends of a bracket or 
U-shaped arm 154 so as to press the presser roller 148 against the platen 
roller 128 from the side of the roller 128 nearer the peeler rod 136. When 
the stepping motor 144 is operated, its intermittently applied power is 
thus transmitted through the first and second gears 142, 140 to the platen 
roller 128 to rotate the platen roller 128 and in turn to cause the 
presser roller 148 driven by the platen roller 128 to rotate. 
A projection 156 extends outward from both ends of the base of the bracket 
arm 154. A spring 158 is connected between the projection 156 and a lug 
159 projecting from the inside wall 126A of the printer body 126. The ends 
of the elongate holes 152 closer to the arm 154A of the bracket arm 154 
are notched upward to form retaining notches 152A. The presser roller 148 
can be spaced from the platen roller 128 by pulling the arm 154A and 
allowing the ends of the rotary shaft 150 to catch in the retaining 
notches 152A. When the ends of the rotary shaft 150 of the presser roller 
148 are later released from the retaining notches 152A, the spring 158 
pulls the presser roller 148 back into contact with the platen roller 128. 
The operation of this printer feed mechanism is now explained. Prior to the 
start of printing, the leading end of the backing strip 120 wound on the 
supply reel 124 is passed between the platen roller 128 and the thermal 
printer 134 which define the printing section 135, is passed around the 
peeler rod 36 and is then passed between the platen roller 128 and the 
thermal printer 134, thereby forming a slack free feed path for the 
backing strip 120. For facilitating the threading of the backing strip 
120, the arm 154A is pulled forward against the force of the spring 158 so 
that the ends of the rotary shaft 150 of the presser roller 148 can catch 
in the retaining notches 152A. This establishes a gap between the platen 
roller 128 and the presser roller 148. 
After the backing strip 120 has been passed through the gap, the presser 
roller 148 is returned to pressure contact with the platen roller 128 with 
the backing strip 120 sandwiched in between. The stepping motor 144 is 
then put into operation for rotating the platen roller 128. The rotation 
of the platen roller 128 unrolls the backing strip 120 from the supply 
reel 124 and draws it into the printing section 135 so that the platen 
roller 128 can cooperate with the thermal printer 134 to print the labels 
122 as required. The portion of the backing strip 120 with the printed 
labels on it is then moved forward toward the peeler rod 136 at a 
prescribed feeding speed. 
Simultaneously, the presser roller 148 pressed against the platen roller 
128 through the backing strip 120 between them is also rotated by the 
rotation of the platen roller 128 so that the backing strip 120 being fed 
out from the printing section 135 is again fed between the rollers 128, 
148 at the same prescribed feeding speed. Since the backing strip 120 fed 
out from the printing section 135 is therefore fed to and turned back at 
the peeler rod 136 in a slack free tensioned state, the labels 122 can be 
reliably peeled off the backing strip 120. The labels 122 peeled off the 
backing strip 120 are either attached to objects to be labeled by hand or 
are supplied to a separate label attacher. The backing strip 120 free of 
the labels 122 is either fed out continuously or cut off at appropriate 
lengths. 
Since the printer feed mechanism according to the present invention is 
configured such that the presser roller 148 is pressed onto the platen 
roller 128 for enabling the platen roller 128 and the presser roller 148 
to cooperatively feed the backing strip 120 out from the printing section 
135, the printer requires only the stepping motor 144 as a power source 
for label feeding. Since the drive roller and the motor for driving the 
drive roller used in prior art printer feed mechanisms are therefore 
unnecessary, the printer can be reduced in both weight and size. 
Although the invention was described with reference to an embodiment that 
uses a gear mechanism as the power transmission means for the stepping 
motor 144, it is alternatively possible to use belt or other power 
transmission means. 
Although the printer feed mechanism according to the invention was 
explained with reference to the feeding of a backing strip having 
temporarily attached labels, it can also be used for feeding tags, plain 
paper, and the like. 
Although the present invention has been described in relation to particular 
embodiments thereof, many other variations and modifications and other 
uses will become apparent to those skilled in the art. It is preferred, 
therefore, that the present invention be limited not by the specific 
disclosure herein, but only by the appended claims.