Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to means for binding one or
more loose sheets into thin booklets using an adhesive co~er.
A known technique for coating both sides of pages wi~h
heat reactivatable adhesive at their junctures inside ~he book spine
involves the use of a slashing action. The kno~n adhesi~e cover
inventions are well suited to bind s~uare or round back books
whose thickness ran~es from one-eighth inch to tWQ inches and
perhaps even larger if required. It has been observed that the
slashing action becomes increasingly vigorous at ~he outermos~ ;
pages as the book-to-be-bound increases in thickness. Alsol the
slashing action is the least at the very center of the book
when ~he book is mounted on the center of an oscillating hea~er.
Although the center pages in any book are never bound as sllb-
stantially as the other pages because of the lesser slashing
action, this is of no real significance because generally the
outer pages are over slashed to guarantee the integrity of the
pages dispo~ed near the center of ~he ~ovk. In addition, the
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thickness of the adhesive laye:r, which usually is in the range of .0;0
inc}les ~ .005 inches plus the vigorousness of the outer slashed pagesJ
tends to manipulate the mol~en adhesive under the centermost pages and
provide adequate bondong of the binding edge to the sheet to be bound.
However, when the book thickness diminishes to one-eighth inch and thinner
~approximately forty sheets of twenty pound paper) the vigorousness and
the effectiveness of the slashing action diminishes and its biggest advantage
no longer prevails.
~ccordingly, it becomes desirable to provide means for effectively
binding these thinner booklets, that is, where the thickness of the total
number of sheets is something less than approximately one-eight of an inch,
into an adhesive cover.
An object of the present invention is to provide a method of
binding loose sheets into a thin booklet using an adhesive cover.
~ lother object of the invention is to provide a thin folded book-
let for holding a small number of sheets wherein the sheets are each attached
to a heat reactivatable adhesive layer.
According to the present invention, there is provided method o~
making a thin booklet by binding loose sheets into c~n adhesive cover com-
prising the steps of: applying a layer of heat reactivatable adhesive tothe center of a sheet of book cover stock; folding the.cover at its center
to create a substantially V-shaped crotch in the cover stock and in the layer
of adhesive attached thereto; placing at least one sheet of paper in said
crotch of the cover stock and heating the crotch of said cover stock in a
folded condition with a heater to heat the adhesive strip; squeezing the `
folded edge of the cover stock to better secure the adhesive to the binding
edges and sides of the sheet or sheets to be bound.
The :~old point is essentially 'IV'! shaped and preferably slightly
rounded on the inside of the "V". The layer of heat reactivatable adhesive
~y be one-half inch to one inch ~ide and may range in thickness of from
.006 inches to .012 inches in thickness to the center or mid-point of the
cover. Ihus, in a folded condition the adhesive is found in the crotch of
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the "~" pre~erably extending up the sides of each of the covers appro.~imately
one-quarter inch to one-half inch.
According to another aspect of the invention~ there is provided
a thin booklet comprisi.ng: a sheet of cover stock; a layer of heat re-
activatable adhesive disposed at the center of said sheet; said sheet of
cover stock being folded along a line extending substantially clown the
middle of said adhesive layer and said sheet of cover stock to define booklet
front and back covers; at least one paper sheet attached to said adhesive
layer; said paper sheet being attached to said adhesive layer at the bottom
edge and part of at least one side of said paper sheet.
Other objects and advantages of the invention will be more readily
apparent when considering the following description together with the
accompanying drawings.
ON TH~ DRAWINGS
Figure 1 is a plan view of a cover in the open position showing a
layer of heat reactivatable adhesive positioned in the center thereof;
Figure 2 is an end view of an adhesive cover in a partially folded
position showing the heat reactivatable adhesive at the folrl point in the
crotch of the "V";
Figure 3 is a view similar to Figure 2 showing a plurality of
sheets to be bound as they are positioned in the cover for binding;
Figure ~ is a view of the partially folded cover similar to that
shown in Figure 1, the folded cover being placed on an oscillating heater;
and
~! Figure 5 is an end view of a partially folded cover with the bound
~I sheets in position in the cover after the adhesive has been heat reactivated
:1, and cooled.
Turning now to the drawings wherein similar reference characters
`j in different views designate similar parts. Figure 1 shown an adhesive cover
10 in an open position. It is to be
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used for binding into one or more loose sheets. An adhesive
layer 12 of heat reacti~atable adhesive and ranging in si~e of
one-half inch to one inch in width and approximately .006 inches
to .012 inches in thickness is disposed at the center or mid-point
of the cover between creases 13. As seen in F~igures 1 and 2, the
adhesive cover comprises front and back cover members 16 and
- 18 respectively. Upon application of the adhesive to the cover
in the flat condition a release agent is applied to the upper sur-
face thereof and the cover 10 i5 folded along line 14 resulting in
the layer of heat reactivatable adhesive 12 lying in the crotch o~
the cover and disposed up the sides of the front and back covers
approximately equidistantly on each side as portions 12A and 12B.
The fold point 14 is essentially "V" shaped. The release agent
may be release paper or powder or other particles.
In order to bind a thin booklet containing anywhere
from one to forty pages, sheets 20 are gathered and inserted into
the crotch 15 of the "V" shaped cover. The folder is then rapped
or sharply jogged so that the sheets drop downwardly and assume
a position substantially as shown in Figure 3. It will be noted
that each of the sheets engage the adhesive 12.
The booklet, that is the cover wi-th the sheets posi-
tioned therein9 is inserted into an apparatus having an oscillating
heater 22 as shown in Figure 4. The heater is oscillated to jog
the sheets into position into the adhesive while at the same time
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the adhesive is being heated to a temperature of apploximately
350F -~ 25. This heating step takes place for approxilllately
30 secQnds. The action of the oscillating heater is ef-fective to
distribute the heat more efficiently than a fixed heater, althougl
the latter may be used. If a fixed heater is used it appears to
require approximately 507~ more process time unless the upper
surface thereof is grooved to accommodate the adhesive - bearing
portion of the cover. While increased temperatures could be used
above the range mentioned above, there would be a risk of scorch-
ing the cover material.
At the conclusion of the timed heating period the cover
10 is removed and the outside of the cover in the area of the ad-
hesive is squeezed between the thlmb and forefinger in order to
further help the adhesive to attach to the edges of the sheets to
~` ~15 be bound in the cover. Alternatively, the cover may be inserted
momentarily into nip rolls to achieve the same result. At this
point the bound booklet has the appearance as generally shown
in Figure 5O Microscopic examination of cut portions of books
and bookle~s processed according to the process just described
indicate that each sheet 20 is secured to the adhesive a~ its
butt edge 24 as well as on one side of the sheet 26 and 28.
It has been noted by testing that the force required
' ~ to separate a sheet 2() From its adhesive as shown in ~igure 5 is
less than that required to separate a "slashed"page from its
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-i 2S adhesive but substantially more than that required to separate a
sheet from its adhesive in, for example, a simple pad. This is
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true when the sheet edges ill the sirnple pad have been abracled
as is sometimes done. In a simple pad the sheet is secured only
at its l)utt edge and tlO adhesive attaches to the sicle of the sheet.
Therefore, the holding power of the adhesive bond is based
strictly on the wiclth of the paper sheet via an abraded or rough-
ened surface. Although provicling an abraded or roughened sur-
face gives a little extra holding power it still does not compare
with the additional holding power provided by the concept of the
invention herein.
It will be apparent that we have advantageously pro-
vided means whereby thin booklets ranging up to approximately
one-eighth inch in thickness may be made utilizing an adhesive
cover for binding loose sheets thereinto. Using this method for
binding a thin booklet has the advantage of providing extra holding
power on the edge of the sheet by permitting the heat reactivatable
adhesive tO attach not only to the bu~t edge of the sheet but also
to a portion of one side thereof. This quite clearly gives a
holding power which is superior to that found in a simple pad.
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