Note: Descriptions are shown in the official language in which they were submitted.
1090196 ~
BACKGROUND OF THE INVENTION
This invention relates to lmprinting and more particularly
to the precision imprinting of labels or tickets with prescribed
coding formats.
When items are to be imprintable with the many different
kinds of characters that can be encountered in practice, the
imprinter must be able to accommodate a wide variety of formats.
Under some conditions, the imprinting will be with characters
~ where only user readability is required, and the characters are
suitable if they can be distinguished by the users without regard
t~o their precision. Under other circumstances, however, the
characters are to be read by machine and precision imprinting
is required to avoid errors. In such cases, a clarity and quality
of printing are required which have not been attainable with
traditional imprinters.
In the usual machine for the imprinting of tickets and
labels, a print head is reciprocatable with respect to an inking
pad where embossed characters on the bands of a print head are
brought into pressure contact with the pad. The print head~is
then moved to a position overlying the stock and impressed
against it to produce the desired imprint. This arrangement
tends to produce a nonuniform imprint because the impact and
inking of the bands with respect to the ink pad tends to be
nonuniform. While the resulting imprints are generally suitable
for user readable characters, they are often unsuitable when the
characters must be read by machine where relatively uniform ink
density is needed. In addition the pressure contact of the bands
with ink pads often produces smearing when the bands are sub-
sequently brought into contact with the stock.
~ccordingly it is an object of the invention to improve the
inking ~echanism by which the bands of a print head are inked
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for the imprinting of stock. Another object is to increase the
uniformity of the imprint made by inked bands which are subsequent
ly impressed on stock. Another object of the invention is to
reduce the tendency for inked bands to produce smearing and
unwanted depositsof ink on the stock
Another characteristic of imprinters commonly encountered in
practice is that the stock is fed over a platen using a recipro-
cating pawl which moves the stock under the print head. This is
accomplished by having a feed finger engage a notch in the stock
and push it over the platen. The customary feed finger often
proves inadequate to keep the feed of labels or tickets of vary-
ing lengths relatively constant and prevent jamming. In addition,
it is necessary to prevent the stock from backing up on the return
stroke of the feed finger. This has typically required units
requiring a great deal of adjustment in order to achieve proper
machine operation.
Accordingly, it is a further object of the invention to
facilitate the advance of stock in a reciprocating feed imprinter.
Another object is to accommodate labels and tickets of varying
lengths while achieving relatively constant speed and preventing
jamming in the machine. Still another object of the invention
is to control the backup of ticket stock during the return stroke
of the feed mechanism.
A further characteristic of prior imprinters with print
bands has been that the bands tend to become clogged after
extensive use. As a result, subsequent ticket impressions become
fuzzy and relatively indistinct. The impressions are nevertheless
usable where the tickets are read only by the users, but they are
generally unsatisfactory where the tickets must be read by machine
The us 1 correct1ve measure is to change the prlnt head. This
1090196
is cumbersome and inefficient. It also adds an unnecessary
complexity to the imprinting operation.
Accordingly, it is a further object of the invention to
facilitate the cleaning of an imprinting machine. A related
object is to achieve the cleaning of the machine without the
need for replacing the print head. Another related object is to
clean the bands of the print head while they are in position on
the machine without disturbing the mechanism of the machine.
The print heads of the ordinary imprinter are generally made
of a rubberized material with molded characters that provide a
reasonable facsimile of the desired imprint. In these cases
where tickets or labels are to be user read alone, variations
in the character impressions do not prevent proper ticket usage.
However, where the tickets or labels are to be processed by
machine, strict standards are required for the character imprint
and the ordinary print bands have been found to be unsatisfactory,
for example, in providing suitable character consistency from
one imprint to another.
Accordingly, it is a further object of the invention to
improve the print bands of machines used in the imprinting of
tickets and labels. A related object is to achieve relatively
consistent character impressions from one imprint to another.
Another difficulty with prior art machines has been that it
had been difficult to adjust the machines when it became neces-
sary to change the stock; for example, by changing from labels
of one thickness to tickets of a greater thickness. The usual
procedure is to make mechanical adjustments in the machine.
Not only are such adjustments time consuming, they cause in-
creased complexity in the machine.
Accordingly, it is still another object of the invention to
achieve stock changeability without the need for complex adjust-
1090196
ments in the machine. A related object is to allow the same
machine to be used for the imprinting of both tickets and label
stock without making mechanical adjustments in the machine.
Representative examples of prior art imprinters are dis-
closed in U.S. patents 3,899,971; 3,379,128; and 3,366,050.
SUMMARY OF THE INVENTION
In accomplishing the foregoing and related objects, the
invention provides machine modifications and methods for precision
imprinting with user prescribed formats.
In one measure for achieving the required precision of
imprinting for decodable labels with machine readable codes, such
as the optical character code, the invention provides a print
head with compression or transfer molded bands that are reinforced
by a compatible fibrous material. This special processing of the
print bands assures relative stability of the print characters
from one impression to another.
Precision feed is assured in accordance with one aspect of
the invention by the use of dual feed fingers in conjunction with
an antibackup roller.
Controlled inking is provided in accordance with another
aspect of the invention by the use of a rack and pinion roller
which contacts an inking supply during one stroke and rolls on
the bands of the print head to apply an initial coating of ink
which is smoothed on the return stroke of the roller. The inking
supply can also be controlled to assure proper metering. of the
ink on each inking roller.
Moreover, the inking supply is replacable by a solvent
member which is used in conjunction with a cleaning pad that is
inserted in place of the platen in order to clean the bands of
the print head. This cleaning operation takes place automatically
1~90196
when the solvent and cleaning pads are placed in the machine, and
the machine is operated for a prescribed number of labelling countc
which can be set by the user.
In accordance with a further aspect of the invention, the
solvent is selected to prevent damage to the constituents of the
imprinter while having sufficient volatility that there is sub-
stantially no dilution of the ink supply during subsequent machine
operation.
DESCRIPTION OF THE DRAWINGS
Other aspects of the invention will become apparent after
considering several illustrative embodiments taken in conjunction
with the drawings, in which:
FIGURE lA is a perspective view of an imprinter in accordance
with the invention.
FIGURE lB is a plan view of a representative ticket which
has been imprinted with illustrative optical code characters in
accordance with the invention.
FIGURE 2 is a perspective view of a representative print
head assembly for the imprinter of FIGURE 1.
FIGURE 3 is a perspective view of a feed mechanism for the
imprinter of FIGURE 1.
FIGURE 4 is a side view of an inking and platen assembly
-for.the imrpinter of FIGURE 1.
FIGURE 5 is a block and schematic diagram of a control
system for the inking and platen assembly of FIGURE 4.
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DETAILED DESCRIPTION
Turning to the drawings, an overview of an imprinter 10 in
accordance with the invention is shown in FIGURE lA. The
principal operating elements of the imprinter 10 include a re-
movable print head 20, a feed assembly 30, and an inking assembly
40 shown positioned beneath a removable dust cover 11. A pawer
train for operating the inking and feed assemblies is contained
within a housing 12.
. To operate the imprinter 10, the dust cover 11 is raised into
position and the power train enabled by a switch 13 on a control
panel 12c at the top of the housing 12. Imprinting is then
initiated by depressing-a start button 14. The imprinting can be
stopped by an operator at any time by depressing a stop button 15.
The number of labels or tags to be imprinted is dialed into a
counter 16 and the unit stops automatically when the desired
count has been attained. A second counter 45 is used in conjunc-
tion with the inking assembly 40, as discussed below.
A supply hub 31 shown in FIGURE 2 (not visible in FIGURE lA)
for labels is located in a hinged compartment 12s of the housing
12 in FIGURE lA.
The imprinter 10 of FIGURE lA is configured to provide
precision imprinting regardless of the coding format employed.
The machine 10 is particularly suitable for the imprinting of
labels and tickets with optically readable characters of the kind
shown on the stock S in FIGURE lB.
The strip of stock S includes two labels, s-l and s-2 with
feed apertures _ and perforations _ between adjoining labels on
the partially imprinted strip S. The label s-l contains a middle
line of character _-2, while the label ~-2 contains outer lines
of chara t rs c-l and c-3. The characters, whlch are set on the
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print head 20 as discussed below, somewhat resemble those used
in the imprinting of checks for machine processing and have the
advantage of being both user and machine readable. It will be
understood that the number of lines of coding, the parameters of
the characters, and the distribution of code characters on the
print head are a matter of choice.
The imprinter 10 of FIGURE lA may be used to provide labels
with ordinary characters by simply interchanging the print head 20
with a print head providing the desired coding format. The
imprinter 10 may also be used with a wide variety of non-user
readable formats, such as the universal product code, by using
a suitable print head.
It is to be noted in connection with the illustrative char-
acters shown in the rows c-1 through _-3 of the illustrative
labels s-1 and s-2 that precise character positioning and imprint-
ing are required for correct machine reading. Thus the optically
readable characters of FIGURE lB are intended to be read not only
by fixed devices, such as at checkout counters, but also by hand
held wands which are passed over the imprinted information for
detection. In general, machine decoding can take place correctly
only if the characters are imprinted with precision.
Thus each ticket or label includes marginal areas where no
imprinting is permitted, failing which there will be an error in
decoding. In addition each line of print must be properly
separated, and the individual characters in any line of imprint
must be correctly aligned. Moreover the character sizes and shape~
must meet prescribed criteria. Edge expansion of the characters,
such as that caused by the improper metering of ink~ can cause
incorrect decoding. The ink coverage must also be relativeiy
uniform, and ink spots outside of the prescribed character area
can cause decoding errors.
1090~96
The print head assembly 20 of FIGURE 2 illustratively has
three sets of bands, B-l, B-2 and B-3, so that three lines of
coding, c-l, c-2 and c-3, may appear on each imprinted item. The
individual bands are set by knobs 21-1 and 21-3 on the right hand
side of the print head 20 for the first and third lines -1 and
c-3, while the knob 21-2 on the left side is used for the second
line _-2. In setting the characters, each of the knobs 21-1
through 21-3 is moved until its pointer _ is over the individual
band to be dialed, such as the band 22-a shown in phantom in
FIGURE 2.
In producing the desired print bands, such as the band 22-a
of FIGURE 2, base material is placed in a mold in slab form for
compression molding and in liquid form for transfer molding. The
base material is a polymeric substance such as urethane which is
reinforced by a polyester fiber made, for example, from poly-
ethylene terephalate. The urethane is a resin with a repeating
structure of ethylcarbonate, also known as ethylurethane. Poly-
ester fibrous material is chosen because of its compatibility
with urethane. It has been discovered in practice that the re-
inforcement of urethane with polyester provides a particularly
stable character band. It is to be noted that bands reinforced
in accordance with the invention cannot be produced by injection
molding since the injection would damage the fibrous reinforce-
ment.
As shown in FIGURES 2 and 3, the feed assembly 30 includes a
forward finger 32f and a rearward finger 32r. A strip of labels
passes from the supply roll 31 around a feed roller 33 to the
adjustable feed fingers 32f and 32r. Each individual label or
ticket on the strip S has a feed slot _ in the upper portion of
lts per ration p as lnd~cated in FIGURE 3.
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The extended finger 32f of the adjustable dual feed finger
assembly 30 is shown locked into the slot a-l of a forward label
s-l. The companion finger 32b is shown locked into the slot a-2
of a succeeding label s-2. The distance between the tip of the
extended finger 32f and the finger 32r is adjustable by shifting
a control knob 32-1 according to the width of the label being
imprinted. The distance between the adjustable dual feed finger
assembly 30 and the print head 20 is also adjustable by shifting
a second control knob 32-2. The adjustable dual feed finger
lQ assembly 32 is reciprocated in standard fashion to move the strip
S to an adjustable print platen 22 (FIGURE 2) where imprinting
occurs.
Backup of the labels is prevented during the return stroke
of the feed assembly 30 by an anti-backup roller assembly 35.
The assembly is mounted to pivot along on axis A (FIGURE 3) which
is parallel to the edges of the labels, and is held against the
labels by an adjustable spring 35s, with a circumferential ridge
36r of a roller 36 in contact with a forward label s-f. The
roller 36 includes a one-way roller mechanism of the kind shown
in U.S. patent 3,899,971; so that there is no hindrance to label
advance, but the contact of the rounded ridge 36r prevents label
retraction. The labels can be advanced manually as desired by
rotating the knob 36k in the direction indicated by the arrow B.
The adjustable print platen 22 of FIGURE 2 may be adjusted to
accommodate varying thicknesses of labels and tickets. If the
platen 22 is in position for the imprinting of labels, it may be
lifted out of place by, for example, a platen lever (not shown).
The platen 22 may then be overturned and placed in a reverse posi-
tion to permit the imprinting of tickets. For that purpose the
platen 22 is configured to provide a different spacing relative to
the print head for its original and reverse positions.
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The inking assembly 40 shown in FIGURE 4 includes an ink
roller 41, an ink pad 42, and a rack and pinion drive assembly 43.
The ink roller 41 is moved by the rack and pinion drive assembly
43 across the ink pad 42 and coated with ink as the adjustable
dual feed finger assembly 30 moves the strip 15 to the imprinting
position on the adjustable print platen 20. The ink roller 41
then moves beneath the print head 20 applying ink to the print
bands such as the bands 22-a through 22-x, located in the print
head 20. As the roller 41 returns to its original position, it
smooths the ink applied to the print bands. The inking process
is repeated for each label or ticket, ensuring that the same
measured amount of ink is applied to each label or ticket.
The print counter 45, as shown in FIGURE 1, records the
number of imprintings. The counter 45 automatically halts the
imprinting process after a prescribed number of imprintings have
occurred, illustratively 50,000. The ink pad 42 must then be
replaced before the imprinting process can continue, ensuring
that the same measured amount of ink is applied to each label or
ticket.
A control system 50 for the inking assembly 40 is shown in
FIGURE 4. For each operation of the imprinter a counter 51 is
incremented. The output of the counter is applied to a register
52 with taps 52-a through 52-x corresponding to various pre-
determined count levels. The attainmen-t of each count level pro-
duces a signal applied through an OR gate 53 to an amplifier 54
whose output supplies a motor 55 which in turn rotates a gear
assemblage 56 and moves the ink pad 42 relative to the roller 41
to maintain a suitable contact pressure between the pad and the
roller 41. Where desired, each different tap of the reg ster 52
can be applied to a different amplifier in order to apply an in-
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creasing pressure as the count which corresponds to usage of the
machine also increases. This compensates for the usage of ink
during the printing operation.
In the particular embodiment of the inking control system 50
shown in FIGURE 5, the ink pad 42 is spaced from a support 45 by
four screws 57-1 through 57-4, which bear against the pad 42. As
the gear assemblage 56 is operated, the screws 57-1 through 57-4
are rotated and threaded out of the support 45, thus moving the
pad 42 towards the roller 41 and its associated pinion and rack
assemblage 43.
In order to suitably clean the print bands, 22-a through 22-x
of FIGURE 4, without interfering with subsequent imprinting opera-
tions, a special solvent is employed which does not damage either
the print bands, or any of the associated apparatus, and at the
same time has sufficient volatility to prevent any dilution of
the ink supply during ensuing operations. A suitable solvent
contains less than 1% aromatic constituents. The remaining 99%
are advantageously a mixture of approximately equal parts of
paraffins and cycloparaffins, but paraffins or cycloparaffins
alone may be employed.
The distillation range of a suitable solvent mix has an
initial boiling point of approximately 240F and a dryness point
of approximately 300F. In practice the distillation range can
vary from about 212F. to about 350F. The solvent mix can be
prepared by combining approximately 55% paraffins that are hexanes
and above with approximately 45% cycloparaffins that are cyclo-
hexanes and above.
1090196
The cleaning operation is effected by replacing the print
pad 42 with a solvent pad, for example of tan foam, (not shown)
and the platen 22 with a cleaning pad, for example of white felt,
(not shown) of absorbent material.
The foregoing description and examples are illustratlve only
and other adaptations, modifications and equivalents of the
invention will be apparent to those of ordinary skill in the art.
