Year: 1887

page_text: Date of Application, 8th Mar., 1887
Complete Left, 20th Sept., 1887
Complete Accepted, 28th Oct., 1887
1, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.L.M.E. do hereby declare the nature of this invention to be as follows:
The present invention relates to improvements in the process and apparatus for
manufacturing improved sensitive flexible photographic films which improvements are
described in the following specification.
The improved apparatus for carrying out this process consists essentially of a
suitable frame or frame work which supports the roll of uncoated paper and the
coating apparatus and of a suitable mechanism in which the coated paper is
automatically hung up to dry in pendent loops.
The roll of paper is provided with suitable journals projecting from each end and
arranged to revolve in bearings in uprights attached to the supporting frame.
The substratum or the emulsion which is to be applied to the paper is contained in
a trough. The paper passes between a pair of guide rollers over another guide roll
and under the coating roll, the lower side of which runs in the fluid in the emulsion
trough.
The paper after leaving the emulsion trough passes over any suitable number of
rolls on its way to the looping and drying part of the apparatus.
Power is applied to the machine by means of a driving shaft which receives motion
from a belt running over a pulley and distributes it by means of a suitable number
of belts. While it is advantageous to apply power to all of the rolls it has been found
in practice that it is possible to feed the paper by driving the roll which for purposes
of distinction I shall call M. in connection with one of the intermediate rolls preferably
The
the roll which I will call 1 next above the trough containing the emulsion.
guide rolls if used are supported in any suitable manner from the main frame so that

page_text: the paper passes between them as it leaves the roll of paper and is to a certain extent
guided and caused to enroll smoothly by them. The second guide roller is sustained
in place by a frame pivoted to the standards so that it can be swung upward to afford
access to the coating roll. This roller serves to wrap the paper closely about the
coating roll on the side on which it runs onto the latter. The coating roll revolves
in suitable journals attached to the trough in such position that the lower portion of
the roll with the paper wound about it is immersed in the emulsion or other liquid.
The roll is made longer than the width of the web of paper which it is designed to
coat in the machine and in order to prevent the liquid from covering the roll so as to
smear the back of the paper or film I employ scrapers or their equivalent at each
end of the roll which are so shaped as to throw the liquid outward beyond the edges
of the paper. The lower surface of the scraper bears on the upper side of the roll
and is made of a shape to correspond with the curvature of the roll. The outer side
of the scraper is inclined to the axis of the roll so that the operation of the scraper
is as the roll revolves to clean the upper surface of the roller at the edge of the paper
and cause the liquid to flow outwards along the roll, thereby preventing any of the
liquid from getting onto the back or uncoated side of the paper film which runs in
contact with the roll. The scrapers are pressed downward against the upper surface
of the roll by a spring or other suitable means. The scrapers should be arranged so
that they can be easily removed, to afford access to the coating roll and in practice
it has been found that one convenient way of accomplishing this result is to support
them by means of a rod or rods passing through a block fastened to another rod
extending across the frame. The blocks are secured to the rod by means of a set
screw which permits of the removal of the scraper from contact with the coating roll.
The web of paper when the machine is in operation passes about the lower side of
the coating roller being coated on its outer or lower surface as it passes around the
roll. The coating roll revolves from the friction of the paper. Sufficient tension may be
maintained on the paper web by any suitable friction device acting on the paper roll or
the guide rolls. The web of paper passes upward from the coating roll over another roller
which revolves in suitable supports or bearings on the frame work and then horizontally
over another roller and then descends passing round one or more rollers below the
coating devices before it passes upwards to the highest roller from which it is delivered
to the looping and drying apparatus. I do not however confine myself to the exact
number of rollers mentioned here. The web of coated paper may be caused to pass
more than once about the coating devices by means of a suitably arranged set of
rollers. The object of passing the coated paper around the coating devices is to allow
sufficient time to elapse before the paper is delivered to the looping apparatus to enable
the coating to set or stiffen. The passing of the paper around the coating apparatus
also increases the friction of the feeding rolls on the paper and enables them to draw
it smoothly and easily. By running the paper upward and downward also it has
been observed that greater uniformity is secured in the coating.
The coating roller may be made of any suitable material but preferably brass
with suitable bearings to support it in the bearings on the trough. Rubber and
wooden rollers have however been used. It is unnecessary to remark that the trough
and all metallic parts which come in contact with the sensitive emulsion should be
formed of or plated with a suitable metal, such as silver, which is not acted on
chemically by the emulsion.
The apparatus for hanging up the paper in loops to dry consists essentially of two
parallel inclined elevating belts or chains and two carrying or conveying chains
provided with suitable mechanical attachments by which a series of rollers upon
which the loops of coated paper are suspended are operated. The whole apparatus is
supported by a suitable frame work. Motion is transmitted to the elevating chains
by means of pitch wheels on a shaft supported in bearings and receiving motion from
the main driving shaft by means of a belt and suitable pulleys. Suitable inclined
ways or guides are arranged to support the chains which travel upward along the
upper sides of these inclined ways. At their upper ends the chains run over a suitable
number of pitch wheels which revolve on suitable studs projecting inward from the

page_text: supporting frame but leaving the space between the wheels open for the passage of
the loops of paper between them. The elevating belts or chains are provided with
one or more projecting studs which carry rollers up the inclined guides. The rollers
are fed onto the chain automatically. The rollers are placed in inclined guides which
are open at their upper ends for this purpose and as fast as the lowest roller is carried
upward by the lugs on the elevating chain the remainder of the rollers drop
downward in the guides, so as to bring the lowest roller in position to be elevated.
A notch or opening is made in the guides to permit of the removal of the lowest
roller by the lugs on the chains. As the rollers are elevated up the inclined guides
they come in contact with the paper hanging in a curve between the roller at the top
of the frame and the first roller on the carrying chains and elevate it in a loop. The
carrying chains are provided with a series of projecting lugs arranged at distances
from each other equal to the width of the pendent loops of paper. As the rollers
arrive in succession at the upper ends of the elevating belts or chains they are
disengaged therefrom and placed on the carrying chains. The rollers on the carrying
chains are made longer than the width of the chains so that their ends project over
the same which are placed just outside of the elevating belts or chains. The first
roller on the carrying chains arriving above the pitch wheels comes in contact with
the lugs on the carrying chains and causes the latter to move onward for a distance
equal to the width of the loops the chains carrying all the pendent loops along at the
same time. The lug is disengaged from the roller as it moves onward by the
inclination given to the elevating belts or chains one set of the pitchwheels being
placed at a lower elevation than than the other so that as the elevating chains
move on down the incline while the rollers travel on horizontally or at
a less
inclination on the carrying chains the lugs are gradually disengaged from their
contact with the rollers. The motion of the carrying chains is thus arrested when
the roller arrives at the last of the series of rollers and the paper hangs in a loop
between the rollers last mentioned and the roller M at the top of the frame, ready for
the next roller in the series to be elevated by the belts or chains forming another loop
of paper as already described. Guides are placed above the outer ends of the rollera
to prevent their being forced upward by the lugs. Between the pitch wheels the
elevating belts or chains are supported by a guide which is fastened to the plates or
frame work which support this part of the apparatus. A spring is used to prevent
the rollers from moving backwards accidentally or by the weight of the loop being
arranged to yield into a recess in the plate when the ends of the rollers pass by it.
The carrying chains are preferably inclined so that their upper sides run downward
slightly thereby ensuring that the rollers shall remain in contact with the lugs or
studs on the chains. The carrying chains may be supported in place hy suitable ways
or guides.
It is almost unnecessary to remark that the apparatus should be used in coating
sensitive emulsion in a suitable non-actinic light. Provision should also be made to
maintain the liquid in the trough at a suitable temperature during the coating
operation by making the trough with a casing into which steam or hot water
may be admitted.
It is preferred to make the trough of such a form that the coating
roller reaches almost to the bottom of it.
As will be readily understood the coating of endless strips or webs of paper with a
thin uniform coating of sensitized emulsion such as is desirable for photographic
purposes is attended with much difficulty and in order to properly distribute the
coating and maintain it of a uniform and even thickness while setting and drying the
paper must be held under a certain degree of tension sufficient to feed the paper
through the machine and hold it flat and at the same time not great enough to draw
the paper unevenly so as to form wrinkles in the surface.
The ordinary feeding devices such as are usually employed for drawing webs of
paper or fabrics through coating machinery cannot be applied in machines of the
kind herein described for the reason among others that the paper as it emerges from
the bath is wet and limp its coating of sensitized gelatine is in a semi fluid state and
will not bear handling, hence the feed devices, which must be positive and uniform in

page_text: action, must be so arranged and applied as not to bear upon or in any way make
contact with the coated face of the paper. It is for this reason that the paper in this
machine is carried around rollers so disposed as to retain the coated web in motion
for a length of time sufficient to permit the hardening of the coating before the web
is delivered to the drying mechanism and two or more of the rolls over which the
coated web is passed are utilized as feeding devices by applying power to rotate said
rolls, the frictional contact with the under surface of the paper being found just
sufficient to properly carry the paper without unduly straining or wrinkling it. It
is to be borne in mind that the paper web as it emerges is impregnated with moisture
and is in condition to receive the impression of any irregular or pointed object
pressed against it from either face, hence nothing but smooth plain faced rolls can
be used as feeders or sustainers. The necessities of the case demand therefore a
feeding mechanism which when applied to the back only of the coated paper shall be
competent to operate thereon by the frictional contact of a smooth and even surface to
draw the paper evenly and regularly through the machine and deposit it in a loose con-
dition upon the drying frame. All these necessary conditions are fulfilled in the machine
herein described. The rollers M and I being driven-the one I applied immediately above
the coating bath and the other M at the delivery end of the machine the roll I
operates upon the web before the moisture has permeated the paper and while the
latter is of sufficient strength to sustain the strain without wrinkling; the roll M
operates to carry the paper extending between it and the roll 1 holds it under tension
over the intermediate rollers, and serves the very important purpose of holding the
web against, and in contact with, the surface of roll I so that the latter will take hold
of and carry the web. By applying the traction at two or more points in the length
of the web, the strain upon the paper is evenly distributed instead of being
concentrated at one point as would be the case were a single driven roll employed.
Under certain circumstances as when a thin emulsion is used or in warm weather
the setting of the coated film may be hastened by reducing its temperature as it
passes from the coating apparatus to the hang up machine. This artificial cooling of
the coated web may be accomplished by the use of a current of cold air or by causing
the web to pass over or through a cold surface or atmosphere, the temperature of
which may be kept down by a current of cold air or water. A fan blower or other
suitable device may be employed to produce the current of air which is cooled by
passing over ice or in any other preferred manner. The air should be carefully
strained from dust.
D IL: OLL JMah 1007

page_text: I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex, M.I.M.E
do hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Since the introduction of the article known as bromide paper for photographic
positives and negatives, numerous attempts have been made to devise a practicable
method of manufacturing the material on a large scale and at less expense both in
time and material, but until the present invention no material progress had been made
and the manufacture was conducted by what may be termed the original processes,
that is to say, either by laying the sensitized material on the paper with brushes, or
the more common method of passing the strip of paper around rollers uniting the ends
of the strip to form an endless band and by the rotation of the rollers causing the
band to travel in contact with a body of emulsion until the entire surface had received
a coating, when it was suspended or left hanging until dried.
A moments consideration of the nature of the sensitized material, the conditions
under which it is applied, and the changes to which the paper is subjected will serve
to show why the ordinary processes of coating and the machinery employed are
incompetent to perform the operations and at the same time preserve the necessary
conditions.
The sensitized emulsions, as ordinarily compounded, contains as the sensitive medium
silver salis dissolved or held suspended in a mixture of water and gelatine, the latter
serving as the vehicle for carrying and holding the sensitive material upon the paper.
The silver salts are a valuable product hence it is desirable that the minimum quantity
capable of producing good work should be employed and for that and other reasons
only sufficient gelatine is mixed in the emulsion to produce, when applied to the
paper, a film layer of just sufficient depth to retain the desired or requisite quantity of
the sensitized medium.
As is obvious, the layer or film of emulsion deposited on the paper must be as free
from spots and irregularities as possible hence any treatment of the paper or coating
before, during or after the emulsion is applied which will produce or favor the forma-
tion of spots, streaks or irregularities in the surface or thickness of the film will result
in the production of defective and unsalable paper involving the loss of much valuable
time, labor and material.

page_text: It must also be remembered that the emulsion is in a liquid condition when applied
to the surface of the paper, that the paper becomes saturated by the water contained
in the mixture, that no opportunity is afforded for a critical examination of the coating
nor can the defects in its surface be reinoved or remedied after the gelatine is once set
and that the entire process has necessarily to be conducted in a photographic dark
room, hence, if the finished article contains the irregularities and inequalities mentioned,
they cannot readily be discovered or detected even by a critical examination, the
coating is so extremely thin-until the final test,-actual use, has been applied and
then, and not before, can the merchantable and practical value of the material be
ascertained.
It will be readily understood therefore, why the ordinary processes employed for
coating cloth, paper and other materials with paint, glue, paraffine and other substances
and compounds not requiring so even and regular a surface as photographic paper
whose irregularities are measured not by instruments, but by the results produced by
the action of light, alone,-why said processes and machines have not and cannot as
rdinarily worked be used in the manufacture of photographic paper.
As before stated, notwithstanding the many attempts made to produce a successful
article of bromide paper by a cheaper and more practicable method, the only process
by which it was generally understood it could be made successfully and the only one
in practical use at the time of this invention, was that in which a belt or band of
paper with its ends united was caused to pass through a bath of emulsion and when
the band had been drawn through the liquid and the coating applied it was either
raised out of the bath and allowed to hang until dry, or what is the same thing was
removed to a drying frame and suspended thereon.
The use of brushes for applying the coating although attempted has not proved
successful, owing to the extreme difficulty experienced in applying the emulsion evenly
throughout the entire surface of the paper.
After many unsuccessful attempts and the expenditure of much time, labor and
money my foreign correspondent has succeeded in discovering a method of manipula-
tion whereby, by a continuous process, he has been enabled to produce a commercial
article of bromide paper expeditiously and cheaply in sheets of any desired dimensions
and with the minimum of waste.
In the following specification and claims the expression web, web of paper, fabric,
paper &c. is intended to mean the web or band drawn from the roll or other source of
supply whether that web be of paper, muslin, silk, or other material which may be
employed; and similarly the expression emulsion, sensitized emulsion and the like is
intended to mean any emulsion solution or photographic substance salted or unsalted,
sensitized or unsensitized. Coating coated &c. refers to the coat or film spread upon
the web.
This improvement in the method, relates more particularly to the treatment of the
paper after the coating has been applied, and consists, generally stated, in so conduct-
ing the operation that after the paper has been supplied with a thin and uniform
coating of the emulsion and while the layer is still in a fluid state the coated web of
paper shall, while under sufficient tension to maintain its surface flat, be drawn or
moved continuously in the same direction until the gelatine in the coating has set,
after which and as rapidly as the web is delivered, it is hung in loops or deposited
upon a frame where it is allowed to remain until the paper has thoroughly dried.
It is of the utmost importance in practising this improved process, that the paper
(which is drawn from a roll of any desired dimensions) should receive an even coating
of the fluid emulsion and it has been found that this can best be secured by causing.
the strip or web of paper to pass into and emerge at an angle from a layer or body of
the fluid emulsion so that the paper as it rises from the level surface of the liquid may
carry only so much of the emulsion as adheres to its surface, the surplus flowing back
into the receptacle.
The web of paper, as it passes through the emulsion, takes up a large quantity of
water which acts to expand and soften it, hence it becomes necessary to apply sufficient
tension to draw it flat over the rollers or other supporting devices. The tension ou

page_text: the paper must be, however, so regulated that, while serving to maintain the web flat
and move it at a uniform speed, it shall not produce wrinkles by the unequal strain
upon the now weakened and expanded paper, for if such wrinkles or other irregularities
on the surface occur, the still fluid coating will run irregularly and form in streaks
on the paper.
It is to be observed moreover, that after the coating has been evenly applied to
the web and while the latter bearing the fluid coating is continued in motion
to preserve and maintain its uniformity, it is essential that the coated face be
unobstructed while the material is setting, that is to say, it must be held and
maintained out of contact with any foreign substance such as pressing rolls, scrapers
or other devices which, if permitted to so much as touch the coating, would defeat
the purpose of the process by destroying the uniform character of the film and
render the latter unfit for photographic purposes.
The rate of motion and distance intervening between the coating devices and the
bang-up frame vary with the state of the atmosphere and the quality of the emulsion.
Ordinarily, in using a machine such as hereinafter described, the rollers are driven at
such speed as will advance the paper 20 feet a minute and with the temperature of the
room maintained at about 65 degrees, the hang-up is located at about 30 feet distance,
that is to say, the paper is maintained in motion for about 1 to 2 minutes after leaving
the coating bath before it is deposited upon the slat of the drying frame. The time and
distance must, of course he adjusted and regulated according to the temperature and state
of the atmosphere and if desired, artificial cooling and drying devices inay he employed,
but under all circumstances in order to prevent blemishes when practising the con-
tinuous process, the coated web must be kept in motion and flat until the gelatine has
set so as to be incapable of further movement upon the surface of the paper and when
this stage has been reached, but not before, can it be suspended in loops upon the
drying frame and remain there until the moisture has evaporated, without injury to
the coating.
The movement of the web after the coating material has been evenly applied and
which is continued until the coating has set or stiffened so as to prevent running, is
a progressive movement, the travel being at all times forwards, but in order that the
flow of the material may be regulated and the uniformity of the coating maintained
it is desirable that the direction i.c.-the angle of inclination of the web during its
progressive movement, should at times be reversed or altered so that at one point it
will travel upwards and subsequently downwards, or vice versa, thereby arresting or
changing the direction of flow, if any takes place, of the liquid coating upon the
travelling web.
Thus, in the machine illustrated, the web as it emerges from the coating device is
caused to move first upward then horizontally, then downwards, then horizontally and
again upward to the delivery roller.
Under certain circumstances, as when it is desired to use a thin emulsion or in
warm weather, the setting of the coated film may be facilitated by reducing its
temperature as it passes from the coating apparatus to the hang-up machine. This
artificial cooling of the coated web may be accomplished by the use of a current of
air, or by causing the web to pass over a surface the temperature of which is kept
down as by a current of cold air, water or a cooling mixture or compound. A fan
blower or other suitable device may be employed to produce a current of air which is
cooled by passing over ice or in any other preferred manner, the air being carefully
strained from dust.
It is obvious that the process herein described is adapted to the coating of webs
or strips of fabric with a surface coating of any material which has a tendency to run
and streak after its application and which possesses the property of setting or stiffening
gradually while the web is maintained in motion, to preserve the uniform surface of
the coating.
It will be observed that according to the present invention three distinct operations
are required to produce the finished article, first, the application of the coating
material. second, maintaining the web in motion until the coating thereon bas set or

page_text: stiffened sufficiently to prevent running, and third, depositing the coated web as
rapidly as the coating sets or stiffens upon a support to dry, and further that all those
operations are performed simultaneously, but upon different portions of the same con-
tinuous web or band of paper, so that while at one point in the length of the travelling
web, the coating is being applied at another it is setting or stiffening and at
still another and more advanced stage is delivered or deposited upon the drying frame.
The improved apparatus for manufacturing sensitive photographic films is repre-
sented in the accompanying drawings, in which.-
Fig. 1 is a side elevation. Fig. 2 is a plan view. Fig. 3 represents a portion of
the apparatus, showing the coating devices on an enlarged scale. Fig. 4 is a side
elevation of the mechanism which operates the rollers which support the coated films
while drying. Fig. 5 is a plan view of the same. Figs. 6 and 7 represent end and
plan views of the coating roll, respectively. Fig. 8 is a plan view of the coating roll,
showing the scraper. Fig. 9 is a sectional view showing the mechanism for feeding the
rollers onto the elevating chains.
This improved apparatus consists, essentially, of a suitable frame or frame work A,
which supports the roll of uncoated paper B and the coating apparatus, and of a
suitable mechanism (shown at the left hand in figure 1) in which the coated paper is
automatically hung up to dry in pendant loops.
The coating apparatus is illustrated on an enlarged scale in figure 3, in which B is
a roll of uncoated paper, the course traversed by which, as it is unwound, coated, and
passed through the machine being represented by the line B¹. The roll of paper is
provided with suitable journals projecting from cach end and arranged to revolve in
bearings in the uprights D, attached to a bar (of the supporting frame. The trough
for containing the substratum or the emulsion which is to be applied to the paper is
represented at E.
F F are a pair of guide rollers between which the paper passes. G is another
guide roll and H the coating roll, the lower side of which runs in the trough E.
I, J, K, L and M are other rollers, about which the paper passes on its way to the
looping and drying part of the apparatus.
Power is applied to the machine by means of the driving shaft N, figures 1 and 2,
which receives motion from a belt running over the pulley O, and distributes it by
means of the belts a, b, c.
While it is advantageous to apply power to all of the rolls, it has been found in
practice that it is possible to feed the paper by driving the roll M, in connection with
one of the intermediate rolls, preferably the roll I next the trough containing the
emulsion.
The rolls FF, if used, are supported in any suitable manner from the main frame,
so that the paper passes through them as it leaves the roll B, and is to a certain extent
guided and caused to unroll smoothly by them. The roller G is sustained in place by
the frame P, pivotted at f to the standards D, so that it can be swung upward to
afford access to the coating roll, as indicated by the dotted lines in figure 3.
The roller G serves to wrap the paper closely about the coating roll H on the side
on which it runs onto the latter. The coating roll revolves in suitable journals
attached to the trough E in such position that the lower portion of the roll, with the
paper wound about it, is immersed in the emulsion or other liquid. The roll is made
longer than the width of the web of paper which it is designed to coat in the machine,
and in order to prevent the liquid from covering the roll so as to smear the back of
the paper or film the scrapers e, figures 6 and 8, at each end of the roll are employed
which are so shaped as to throw the liquid outward beyond the edges of the paper.
The lower surface of the scraper bears on the upper side of the roll, and is made of a
shape to correspond with the curvature of the roll. The outer side of the scraper is
inclined to the axis of the roll, as shown in figure 8, so that the operation of the
scraper is, as the roll revolves, to clean the upper surface of the roller at the edge of
the paper and cause the liquid to flow outward along the roll thereby preventing any
of the liquid from getting onto the back or uncoated side of the paper film which runs
in contact with the roll. The scrapers are pressed downward against the upper surface

page_text: of the roll by a spring g, figure 6. The scrapers should be arranged so that they can
be easily removed to afford access to the coating roll; and in practice it has been found
that a convenient way of accomplishing this result is to support them by means of a
rod or rods d passing through a block h, fastened to a rod i, extending across the
frame G. The blocks are secured to the rod by means of a set screw which perinits
of the removal of the scraper from contact with the coating roll.
The web of paper when the machine is in operation passes about the lower side of
the coating roll H, being coated on its outer or lower surface as it passes around the
roll. The coating roll rovolves from the friction of the paper. Sufficient tension may
be maintained on the paper web by any suitable friction device acting on the paper
roll B or the rolls F F. The web of paper passes upward from the coating roll about
the roller I, which revolves in suitable supports or bearings on the frame-work, and
then horizontally about the roller J, and then descends passing about one or more
rollers K L below the coating devices, before it passes upward to M, from which it is
delivered to the looping and drying apparatus. The web of coated paper may be
caused to pass more than once about the coating devices by means of a suitably
arranged set of rollers. The object of passing the coated paper around the coating
devices is to allow sufficient time to elapse before the paper is delivered to the looping
apparatus, to enable the coating to set or stiffen. The passing of the paper around
the coating apparatus also increases the friction of the feeding rolls I and M on the
paper and enables them to draw it smoothly and easily. By running the paper
upward and downward, also, it has been observed that greater uniformity is secured
in the coating.
The coating roller H is preferably brass, with suitable bearings to support it ou the
centres on the trough E. Rubber and wooden rollers have however been used. It is
unnecessary to remark that the trough and all metallic parts which come in contact
with the sensitive emulsion should be formed of or plated with a metal-such as silver
which is not acted on chemically by the emulsion.
The apparatus for hanging up the paper in loops to dry consists essentially of two
parallel inclined elevating belts or chains S S¹ and two carrying or conveying
chains TT provided with suitable mechanical attachments by which a series of
rollers UU upon which the loops of coated paper are suspended, are operated. The
whole apparatus is supported by a suitable framework, which, for convenience of
illustration, has been omitted in the drawings. Motion is transmitted to the elevating
chains S S¹, by means of sprocket wheels jj, on a shaft supported in bearings kk,
and receiving power from the main driving shaft N by means of the bolt a and
suitable pulleys. Suitable inclined ways or guides V are arranged to support the
chains, which travel upward along the upper sides of these inclined ways, as indicated
by the arrows in the drawings. At their upper ends the chains run over the sprocket
wheels YY, Y Y¹, which revolve on suitable studs 11, figure 4 projecting inward
from the supporting frame, but leaving the space between the wheels Y Y, Y' Y',
open for the passage of the loops of paper B between them. The chains S S¹ are
provided with one or more projecting studs m m which carry the rollers U up the
inclined guides V. The rollers are fed onto the chain automatically by the device
represented in figure 9, in which j represents one of the sprocket wheels, and n an
inclined trough or guide for the ends of the rollers, arranged just outside of the chain
and wheel. The rollers are placed in the inclined guides n which are open at their
upper ends for this purpose, and as fast as the lowest roller is carried upward by the
lugs m ou the chain S S', the remainder of the rollers drop downward in the guides
so as to bring the lowest roller in position to be elevated. A notch or opening is made
at o, figure 9, in the guides to permit of the removal of the lowest roller by the lugs
on the chains. As the rollers are elevated up the inclined guides V V, they come in
contact with the paper hanging in a curve between the roller M at the top of the
frame A and the first roller U on the chains T T and elevate it in a loop, as shown at
B3 B³, figure I. The chains T T are provided with a series of projecting lugs p p
figures and 5 arranged at distances from each other equal to the width of the
pendant loops of paper B*. As the rollers arrive in succession at the upper ends
B

page_text: of the chains S S they are disengaged therefrom and placed on the chains T T' by
the mechanism shown in figures 4 and 5. The rollers U are made longer than the
width of the chains so that their ends project over the chains T T', which are placed
just outside of the chains S S¹. The roller U, figure 4, arriving above the
sprockets Y Y comes in contact with the lugs on the chains T T' and causes the
latter to move onward for a distance equal to the width of the loops, the chains carrying
all the pendant loops B along at the same time. The lug m is disengaged from
the roller as it moves onward by the inclination given to the chains S S¹, the
sprockets YY being placed lower than the sprockets YY, so that as the chains S S¹
move on in an inclined direction, while the rollers travel on horizonially or at a less
inclination on the chains T T the jugs mare gradually disengaged from their contact
with the rollers, as represented at m¹ figure 4, so that the motion of the chains T T¹
is arrested when the roller arrives at U¹ figure 4 and the paper hangs in a loop
between rollers U and M, ready for the next roller in the series to be elevated by the
chains S S forming another loop of paper, as already described.
Guides W, figure 4 (indicated by dotted lines in figure 5) are placed above the
outer ends of the rollers, to prevent any tendency in the rollers to be forced upward
by the lugs m and p. Between the sprockets Y Y¹, the chains S S' are supported by
the guide Z, figure 4, which is fastened to the plates or framework 99 which support
this part of the apparatus. A spring r is used to prevent the rollers from moving
backward accidentally, or by the weight of loop between U and M, being arranged
to yield into a recess in the plate q when the ends of the rollers pass by it. The
chains TT are preferably inclined so that their upper sides run downward slightly,
thereby insuring that the rollers shall remain in contact with the studs or lugs pon
the chains. The chains T T may be supported in place by suitable ways or guides.
It is unnecessary to remark that the apparatus should be used in coating sensitive
emulsion in a suitable non-actinic light. Provision should also be made to maintain
the liquid in the trough E, at a suitable temperature during the coating operation by
making the trough with an internal partition, into which steam or hot water is
admitted.
For the purpose of illustrating one mode of applying a cooling medium I have
shown in dotted lines figure 1 a tank marked Q for the reception of a refrigerating
compound or liquid.
It is preferred to make the trough of such a form that the coating roller reaches
almost to the bottom of it, as indicated by the dotted lines in figure 3.
As will be readily understood, the coating of endless strips or webs of paper with a
thin uniform coating of sensitized emulsion such as is desirable for photographic
purposes, is attended with much difficulty; and in order to properly distribute the
coating and maintain it of a uniform and even thickness while setting and drying, the
paper must be held under a certain degree of tension sufficient to feed the paper
through the machine and hold it flat, and at the same time not great enough to draw
the paper unevenly so as to form wrinkles in the surface.
The ordinary feeding devices, such as are usually employed for drawing webs of
paper or fabrics through coating machinery, cannot be applied in machines of the
kind herein described, for the reason among others, that the paper as it emerges from
the bath is wet and limp, its coating of sensitized gelatine is in a semi-fluid state and
will not bear handling; hence the feed devices, which must be positive and uniform
in action, must be so arranged and applied as not to bear upon or in any way make
contact with the coated face of the paper. It is for this reason that the paper in this
machine is carried around rollers so disposed as to retain the coated web in motion for
a length of time sufficient to permit the hardening of the coating before the web is
delivered to the drying mechanism, and two or more of the rolls over which the coated
web is passed are utilized as feeding devices, by applying power to rotate said rolls,
the frictional contact with the under surface of the paper being found just sufficient to
properly carry the paper without unduly straining or wrinkling it.
It is to be borne in mind that the paper web as it emerges, is impregnated with
moisture, and is in condition to receive the impression of any regular or pointed

page_text: object pressed against it from either face; hence nothing but smooth plain faced rolls
can be used as feeders or sustainers. The necessities of the case demand, therefore, a
feeding mechanism which, when applied to the back of the coated paper, shall be
competent to operate thereon by the frictional contact of a smooth and even surface
to draw the paper evenly and regularly through the machine and deposit it in a loose
condition upon the drying frame. All these necessary conditions are fulfilled in the
machine herein described. The rollers M and I being driven-the one I, applied
immediately above the coating bath and the other M, at the delivery end of the
machine the roll I operates upon the web before the moisture has permeated the
paper and while the latter is of sufficient strength to sustain the strain without
wrinkling. The roll M operates to carry the paper extending between it, and the
roll I holds it under tension over the intermediate rollers and serves the very important
purpose of holding the web against and in contact with, the surface of roll I, so
that the latter will take hold of and carry the web. By applying the traction at two
or more points in the length of the web the strain upon the paper is evenly distributed,
instead of being concentrated at one point, as would be the case were a single driven
roll employed.
Having now particularly described and ascertained the nature of this invention,
as communicated to me by my foreign correspondent, and in what manner the same is to
be performed, I declare that what I claim is:
1. The herein described process of coating a continuous web with a uniform layer
of emulsion, consisting in applying the emulsion to one side of the web as it is passed
through the coating device in artificially cooling the coated web in keeping the coated
web in continuous motion and the coated surface free from damage by contact until it
has set and finally in delivering the web to a suitable rack or frame to dry,
substantially as described.
2. The herein described process of coating a continuous web with a uniform layer
of emulsion, consisting in applying the emulsion to the lower side of the web as it is
passed through the coating device in carrying the coated web on suitable supports
around the coating apparatus and keeping it continuously in motion and the coated
surface free from damage by contact until the emulsion has set or stiffened sufficiently
to prevent flowing and in subsequently delivering the coated web to a suitable drying
fraine or rack substantially as and for the purposes set forth.
3. The herein described method of producing uniform coatings upon continuous
webs which consists in applying the coating material in a fluid condition evenly upon
the face of the web and in changing the flow of the coating upon the web to regulate
and maintain its uniformity and maintaining the web in motion and its coated surface
free from damage by contact until the coating has set hardened or dried sufficiently to
prevent running substantially as described.
4. The herein described improvement in the art of producing photographic paper
which consists in applying to one face of the web a uniform coating or surface of fluid
sensitized emulsion by causing the paper to emerge from the level surface of a body
of emulsion and subsequently maintaining the coated web in motion continuously and
uniformly in the same direction and the surface of the coating free from damage by
contact until the emulsion has set or stiffened sufficiently to prevent running
substantially as and for the purposes set forth.
5. The herein described process of producing sensitized photographic paper
consisting in applying to a moving continuous web a uniform layer of sensitized
emulsion keeping said web in motion and the coated side free from damage by contact
until the coating is set or stiffened sufficiently to prevent flowing and finally drying
the coating.
6. The herein described method of producing uniform coatings upon continuous
webs which consists in applying the coating material in a fluid condition evenly upon
the face of the web and subsequently maintaining the web in motion and its coated
surface free from damage by contact until the coating has set or hardened sufficiently
to prevent running substantially as described.

page_text: 7. The herein described continuous process of producing sensitized photographic
fabric consisting in applying in a suitable non-actinic light to a running continuous
web a uniform layer of sensitive fluid emulsion keeping said web in motion and the
coated side free from damage by contact until the coating is set or stiffoned sufficiently
to prevent flowing and finally while the web is in motion and the coating being applied
depositing that part of the web on which the coating has set or stiffened at rest with
relation to its supports to dry.
8. In a machine for coating a continuous web with emulsion the specified arrange-
ment of the rollers about the emulsion trough whereby the coated web is carried around
the said trough without the coated side coming in contact with said rollers and space
is economised and sufficient time allowed for the coating to set before being transferred
to the hang-up apparatus substantially as described and illustrated in the accompanying
drawings.
9. The complete apparatus constructed and operating substantially as and for the
purpose described and illustrated in the accompanying drawings.
W. P. THOMPSON & BOULT,
Agents.
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