Note: Descriptions are shown in the official language in which they were submitted.
2 U ~, ~ 21 Cl~N/WRB
TABBED TRANSPARENCY
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Technical Field
The present invention relates to transparent
imaging sheets for use in mechanical copying machines.
~ore particularly, the -present invention relates to a
composite sheet construction comprising a transparent
sheet and an op~que member adhered thereto. Such
composike, transparent sheets can be used in state-of-the
art copying machines employing pho~o sensing means to
monitor the progress of isnaging sheets through the feed
mechanism~
Back~round Art
Modern copying machines employ sophisticated
mechanism~s to allow them to select imaging sheets from a
~tack o~ Esuch ~sheets and, by the use of rollers, whaels,
b~ltts, and the like, cau~-se such sheets to rapidly and
prucl~ly b~ movQd past variou~s points in the machine ~o
C~ Se ~he ~sh~ets ~o be imayed, proc~ssed and subsequently
d~os:lkud ln a receptacle accessible to the machine
~0 ~p~r~tos~. Such machinecs can produce a yreat number of
copl~s ln a ~latlvely ~hort time span. To accomplish
thi~l ta~k, the ~he~ts mu~t be fed rapldly and preci~ely
througtl ~he m~chlne- Copy machines of this type can
~ypically provide up to 120 copies per minute.
~ n order ~hat the rapid handliny and proc~siny
of th~ ~heet~ can be accomplished, sophisticated sensing
mechanism~ have been built into ~uch machines to preven~
damage to of the machine if wrinkling, tearing or other
deformation o~ the sheet occurs. For example, the~e
sensing mechanisms will halt operation of the rnachine if
jamming occurs so as to avoid any damage to ~he machine
caused by such jamming. Many sensing mechanisms employ
photo sensors which monitor the passage o~ the sheet
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through the machine. In order for such sensing mechanisms
to operate the sheets must be opaque in certain areas so
as to interrup~ the light beams employed in ~he photo-
sensing mechanisms. Accordingly, when transparent sheet
materials are used in such copying machines they must be
rendered opaque in selected areas in order to operate
properly in the machines.
Some copying machines require that only a small
portion o~ the transparent sheet be rendered opaque and
the printing of a dark line along the top or side of such
sheets is sufficient. Other machines require that a
gr~ater area of the sheet be rendered opaque or that prime
image areas of the sheet be opaque. Obviously, this
situation precludes using a tran~parent sheet with an
unobtrusive opaque line printed alon~ one edge. In order
to u~e transparent sheets in such machines, a paper
backing, substantially coextensive with the sheett is
adh~red to the transparent sheet and removed therefrom
~oll~witlcJ passaye through the machine. Generally, the
~ pap~ ~h~t i~ adhered to the transparenk sheet by a ~hin
lln~ oE adh~iv~ applied continuously or discontinuously
pr~Xilnat~ d common edg~ of th~ mated sh0e~s. When the
~n~p~r~n~ ~hQ~t ha~ been imaged the operator tears the
h~t ~ro~n ~he transparent sh~et and discards the
h~t~
'l'h~ u~e of such paper backing sheets ha~ not
~rovlded ~ ~atisfackory imaying manifold. When the paper
~h~ orn from the transparent ~heet, visible paper
~lber~ r~main on the transparent sheet in the area of the
adhesive bond. When a discontinuous adhesive bond is
u~d, ~or ~xample, a "dashed" adhesive line, the amount of
paper fibers remaining on the transparent sheet following
removal of the paper sheet is somewhat reduced. However,
a more serious problem can develop in that such composite
sheets have a greater tendency to jam in the feed
mechanism of the copy machines.
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Disclosure of Invention
_ _ .. . .
The present invention relates to transparent
imaging sheet manifolds or "sets" for us~ in copying
machines such as the xerographic machines often referred
S to as "plain paper" copying machines. More particularly,
the present invention relates to an imaying sheet manifold
comprising, in combination, a transparent, polymeric sheet
imageable in a copying machine; an opaquei paper sheet;
and an adhesive composition interposed between and
adhering the paper sheet to the transparen~ sheet. The
adhesive composition is selected to have a greater
adhesive affinity for the surface of the paper sheet than
for the other elements of the manifold, that is, the
transparent sheet or the adhesive itself. In addition,
the adhesive is formulated so that the peel strength of
the adhesive bond is less than the adhesive bond strength
whlch would tear the paper fibers when the sheets are
~parated. 'rhis careful balancing oE adhesive properties
allows the papcr sheet to be peeled from the transparent
~3 ~h~3~t without l~aving a vislble paper resîdue on the
~r~n~sp~r~flt ~heet, preferably without leaving any
~ut)~-s~rlkl~l ~dhesiv~ ~e~idue on the t~ansp~rent sheet.
Th~ ~hee~ o the manlfold are preferably joined
by ~ c~fltlnuous llne of adhesive such as a line of
~rj ~ldh~g iV~I pro3~iln~te ~ common edge.
numbe~ oE adhesives can be formulated to
~r~vlde the characteristics noted above. For example, the
n~tur~l rubber adhesives have been Eound to work well and
certain o~her synthetic, polymeric adhesives have also
ba~n ound to have the necessary characteristics. For
example, poly(vinylacetate) polymers have been found ko
provide accep~able adhesives, particularly when modified
by the addition o~ an ester to modify ~he adhesive
characteristics of the poly(vinylacetate). In addition,
an isooctylacrylate/acrylimide copolymer in combination
with a release agent coated on the transparent sheet has
proven to be a suitable combination.
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The imaging sheet manifolds according to the the
present invention also have sufficient dimensional and
structural stability so that they do not cause excessive
~amming in a copying machine. When processed, the
manifold sheets of the present invention can be readily
separated without leaving a visible residue of paper
fibers attached to the transparent sheet.
Detailed Description
The image-receiving portion of the manifold of
the present invention is a transparent, polymeric sheet.
Representative of such polymeric sheets are poly(e~hylene
terephthalate) and polycarbonate sheets ranging in
thickness from about 2 to 5 mils (50-2Q0 micrometers).
The image-receiving surface of the sheets may be treated
with various surface treatments, known per se, to improve
their imaging ability. In addition, antistatic agents and
~rlction reducing coatings may be employed as is well
known in the art. Typical antistatic materials are
clu~ern~ry ammonlurn salt3 while pulveri~ed urea formalde-
hyde partlclPs aan be u~ed to provide a friction reducing
c~lncJ.
A~ not~d herein, the tran~parent sheet must be
r~nd~r~d opaclue by some means in order to be usefuL in a
-~ cop~ln~ machine~ employing photo3ensiny mechanism~ to
conkro;l th~ Eeed mechanism. rrhis i8 accompli~hed by
~dherln~J an opa~ue, paper sheet to the underside ~non
lm~cJe-receiving side) of the transparent sheet. The
mani~o1d is then opaque and the copy machine "sees" an
opaque piece of paper passing through. Following imaging,
the mani~old i8 separated by peeling the paper sheet from
~he transparent sheet.
The paper sheets useful in the manifold can be
selected from a wide variety of paper materials. The
paper should be opaque and should have sufficient dimen-
sional stability, heat resistance and the like to resist
wrinkling on passage through the copying machine. The
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operating characteristics for the various copying machines
may also dictate the paper to be employed For example,
copying machines having relatively high ~using station
temperatures can utilize higher weight papers whereas
copying machines having low fusing station temperatures
may perform better with lower weight papers. Generally,
papers in the weight range of 18 to 46 pounds (8-21 kg)
per ream (500 sheets of 24~' x 36" (70 x 91 cm) paper) are
satisfactory.
It has been found that a machine glazed or
calendered paper is preferable as there is less likelihood
of paper tearing when the paper sheet is pe~led from the
transparent sheet.
The adhesive employed in the present invention
must be formulated to have carefully balanced adhesive
properties. On the one hand the adhesive must adhere the
pape~ ~irmly to the transparent sheet so that the mated
~sheet~ will not be separated during routine handling and
t3ark~glncJ or during imaging in the copy machine. On She
~th~r hand, the adhesive must allow the paper sheet to be
r~dlly ~orn rom the transparent sheet without leaving
~p~r Elb~r~ ~dh~red thereto.
It ha~ b~en ~ound by the preserlt inventor that
th~ ~lh~f~lv~ must have a bond strength tv the transparent
h~t In~t~rial or a cohesive strength which will not
~ 0tl th~ te~r ~trength of the paper employed- Thus, as
l~n~ a~ th~ adhesive bond can be broken cohesi~ely or at
th~ adhosive-adherend interface with a force that does not
exc~ed thl~ value, paper fibers will not be torn frorn the
sur~ace of he paper and be left on the transparent sheet.
For example, an adhesive bond having a peel strength of
less than about 1400 grams per inch width ~550 g per cm)
when measured in 180 degree peel at 100 inches/minute
(40 cm/min) using 30 pound ~13.6 kg) glazed paper and 3
mil (76 micrometer) thick polyester, is satisfac~ory. If
the adhesive bonds more strongly than this, fibers will be
torn from the paper when the sheets are separated. It is
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preferred that the adhesive bond be preferentially broken
at the inter~ace between the adhesive and the transparent
sheet so that substantially no adhesive resldue is left on
~he transparent sheet. This can be readily accomplished
with certain adhesive materials as well b~ seen
hereinafter.
Adhesives having the necessary bonding
properties can be formulated by skilled workers in the
adhesives art once the desired criteria have been
established. Such formulation work involves selecting an
adhesive material which will have the necessary physical
properties and affinity for the surfaces to be joined
followed by modification of the polymer, if necessary, to
"fine tune" th~ balance of adhesive properties.
A variety of polymers can be used as the base
polymer wi~h which to formulate the adhesives. Rubber and
poly(vinyl acetate) are two such materials which are
particularly useful Eor preparing water-based adhesives.
~a~ural latex rubber is a par~icularly useful base
m~t~rial ~or water-based adhesive~ since it is resilient,
~ou~h ~nd has ~ood ayeing properties. The tack can be
t~a~lly ad~u~t~d by proper compounding and the ageing
p~p~rkl~ can b~ improved by the addition o~ antioxidant
h~r known addltivas A useEul Eormulation comprises
l p~r~ by welght oE 60% solids natural rubber latex,
~0 p~r~ terperle tackiying resin, 0.2 parts antloxidant,
~7 pclr~ ~hermopl~stic resin/ester rnaterial, 2.8 parts
pl~lcl~r, 2.3 parts 26 Degree Baume ammonia and 5
par~s water.
A difEerent class of adhesive which has al~o
been found to perform satisfactorily is a modified
poly~vinyl acetate) adhesive. The main ingredients of
such an adhesive are about 46-51 parts by weiyht
poly~vinyl acetate), 2-4 parts diethylene ylycol
dibenzoate, 2-3.5 parts dipropylene glycol dibenzoate and
44 parts by weight water These adhesives are
particularly desirable since they also tend to be
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substantially removed from the transparent polyester sheet
when the paper sheet is peeled from the polyester sheet~
A number of other adhe~ives can be used in
combination with release agents or other surface modifyinF~J
coatings~ For example, an isooctylacrlate/acrylimide
copolyrner in organic solvent can be used in combination
with a low adhesion surface treatment such as a urethane
ha~ed on poly(octadecyl i~ocyanate). Ethylene/vinylacetate
copolymer hot-melt adhesives can also be forrnulated to
provide the necessary adhesive properties.
In addition to the above adhesives, a unique
class of adhesive materials based on the use of
inherently-tacXy, elastomeric, copolymer microspheres can
be employed in the present invention. These tacky
microsphere~ provide a pressure-sensitive adhesive which
ha~ a low degree of adhesion permitting ready ~eparation
of adhered object~. Microspheres of this type are
di~clo~ed in ~.S. Patent~ 3,691,140 and 4,166,152. These
~.lcky rnlcro~pheres may be adhered or anchored to the paper
f~h~et oE th7 m~nlfold by primers, adhesive3 or binders, see
~r ~x~mple U.S~ 3,857,731, to provide a low-tack paper
~h~3t. whl~h can be u~ed to prepare an imaging sheet
r~ r~ lrl ~Iccordl.ng to the pre3ent invention. Manifolds
tF3r.~p~ad uF-Jin~J the~e mlcro~phere coated paper ~heets can be
n3ge~ ~ncl ~e paper ~heet sub~equently separated without
t~n!~V ln~J Vl~it)lC? paper fibers or adhesive re~idue on the
~rln~pa rerlk ~hee t.
The mclximum bond strength which can be built
Into tha ~clhe~ive can be determined by testiny the paper
to be u~ed in the maniEold with adhesives having varying
borltl ~trengths. A 180 degree peel te3t with variou~
adhesives will provide the value at which paper fibers
are removed. With 30 pound (13.6 kg~ machine glazed bond
paper this value has been found to be about 1400 grarn~
per inch width (550 g/cm) at 100 inches/minute (40 cm/min)
at room temperature. Various adhe~ives can then be
formulated to fail in cohesion or in adhPsion to the
selected transparent substrate (e.g~ plain or release-
coated polyester) at pee]. valu~s below the tear strength
value previously determined.
The imaging sheet manifolds of the presen~
invention can be prepared on conventional forms-making
equipment by extruding a continuous bead of the adhesive
along one edge of the paper sheet or the transparent sheet
and then mating the sheets and allowing the adhesive to
dry. Water-based adhesives are preferred from a cost and
pollution standpoint. Moreover, because there is
considerable static electricity generated on certain
formsmaking equipment an organic solvent-based system
coula pose a potential fire hazard.
The imaging sheet manifolds o~ the present
lnvention can be satisfactorily used in copying machines
employing photosen3ing apparatus. The manifolds are
opa~u~ and can be processed by the copy machine
ntlalLy ~imilar to a paper sheet and do not cause
~xc~ive ~ammlng. When proce~sed, the manifold can be
~parat~d by p~cllng the pap~r sheet Erom the transparent
~hr3~t wi~holJt leav1ng ~ny paper residue on the transparent
~h~ot whlch l~ vi~ible to the naked eye.
Th~ ~re~ent invention can be urther illustrated
by ro~orenc~ to the ~ollowiny example~.
~n adhe~sive for bonding an imaging shee~ mani-
~old w~s prepared by blending a 56% solids aqueous
emulsion o poly(vinylacetate), available from the H. B.
Fuller Co~ as adhesive S6920, with a 56% solids aqueous
emulsion wherein the solids comprise 76~ poly(vinyl-
acetate) and 20% of a S5:45 weight ratio blend of
diethyleneglycol dibenzoate and dipropyleneglycol
dibenzoate, available from the H. B. Fuller Co. as
adhesive PA 3473. Various blends ran~ing from 10% by
weight adhesive PA 3473 and 90% adhesive S6920 to 90% by
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weight adhesive PA 3473 and 10% adhesive S6920 were
prepared.
The peel strengths of these adhesive blends as
well as each adhesive separately were tested by ~onding
sheets of 30 pound (13,6 kg) machine-glazed bond paper
(Thilmany Paper Company) to 3 mil (76 micrometer)
polyester. One inch (2.5 cm) strips were pulled in 180
peel at 100 inches~minute (40 cm/min) ~room temperature)
and the average peel force in grams measured. The results
ar~ shown in Table 1.
Mani~old sheets were prepared by bonding a 35
pound machine-glazed bond paper to 3-mil (76 micrometer~
polyester with an adhesive comprising 60 parts by weight
adhesive PA 3473 and 40 parts adhesive S6920. A con-
tinuous, 1/8 inch (0.3 cm) bead of adhesive was placed
alony one long edge of an 8 1/2 inch by 11 inch (22 x 28
cm) shee'c of the paper and mated in register with the
polyester sheet to form a manifold. When dried, these
~h~cts could be imaged in a copy machine and peeled apart
wlthout L~aving any visible paper residue or adhesive
~ldue on the polyester sheet. These mani~old~ were
con~inuou~ly ~ed to a Sharp 810 copier and no machine jams
~3~U~cl during the ~eeding of 1200 consecutive manifolds
~t which tlma th~ was discontinued. A competitive
m~nl~ld h~vlng a di~contlnuous adheslve line was
~milarly ~d khrough the sam~ copier and during the
~kincJ o~ 60 eopi~, 3 machine jams occurred.
Example 2
3V ~ natural latex rubber adhe~ive for bonding an
imaging sheet mani~old was prepared which comprised 167
parts oE 60% solids natural rubber latex, 8 parts terpene
resin ~Piccolyt* S115), 2.8 parts plasticizer (Plastinox*
2246), 0 65 parts thermoplastic resin/ester material
(Polypale Wood Rosin), 0.16 pa~ts antioxidant (Santovar Aantioxidant), 2.3 parts 26 Degree Baume Ammonia and 58
parts water.
Tr~c~cle~ k
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As prepared, the above adhesive had a viscosity
of less than 100 cps~ The viscosity was increased for
flow control on the formsmaking e~uipment to about 5000
cps by the addition of hydroxy ethyl cellulose (Union
Carbide, QP 52000-H) or sodium polyacrylate (Diamond
,~ Shamrock, Modicol VD)~
The peel strength of this adhesiY~ was tested as
in Example 1 and the results are shown in Table lo
Manifold sheets were prepared by bon~ding a 35
pound (15~9 kg) machine-glazed paper ~Thilmany) to 3-mil
(76 micrometer) polyester as in Example 1. The manifold
sheets could be imaged in a copying machine and the paper
sheet peeled from tha polyester without leaving a paper
residue on the polyester sheet.
Exam~le 3
A manifold according to the present inven~ion
wa~ pr~pared by treating a polyes~er sheet on the surface
alon~J ono edgo with a polyoctadecylisocyanate-based
~0 ur~thane. 'rhi3 ~urface treatment provided a low adhesion
~u~a~ treatment. ~n isooctylacrylate/acrylimide
aopoly~ ln organla ~olvent was applied to a sheet of
bond p~per. ~ollowin~ drying at ambient temperature -the
~h~ak~ w~ m~tad in regis~er to form an imaging shee~
~n~nl.o~d.
Th~ ~bove sheets could be imaged in a copying
~n~chln~ ~nd the paper sheet subsequently peeled from the
~olye~ter aheet without leaving any visible paper residue.
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* 1;~alelv1~r~k
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Table 1
Peel Force,
Adhesive Grams_ Comments _ _
Natural Rubber1230 No Paper Residue
PA 3473 ~ Paper Tore Could Not Remove
S 6920 < 10 No Paper Residue
10/90 * < 10 No Paper Residue
10 20/80 * < 10 No Paper Residue
30/70 * < 10 No Paper Residu~
40/60 * < 10 No Paper Residue
50/50 * 320 No Paper Re~idue
60/40 * 1320 No Paper Residue
15 70/30 * -~ Paper Tore-Could Not Remove
~0/20 * -- Paper Tore-Could Not Remove
90/10 * -- Paper Tore~Could Not Remove
~ W~l~Jhk ~tios PA3473/S6920
