FIELD OF THE INVENTION
[0001] The present invention relates to applicating processes and apparatus for use in imaging
technologies. The invention particularly relates to apparatus and processes for applying
active chemistry to exposed photosensitive media, particularly developer, activator,
and fixing chemistry to exposed silver halide imaging media.
BACKGROUND
[0002] Processing of conventional silver halide photosensitive materials has been and remains
most commonly practised by the use of tanks containing the requisite processing solutions,
through which the media is transported via a suitable arrangement of rollers and guides.
The rotational movement of the rollers helps to agitate the media, along with impellers
and recirculation pumps within the tank to achieve even processing. Despite the dominance
of tank processing methods in commercial operation, some significant disadvantages
are associated with this approach. By their nature, tank processors are susceptible
to oxidation which reduces the lifetime of some chemistries. Additionally, tank processors
usually contain large volumes to achieve the necessary processing times at acceptable
transport speeds. Taken together, these drawbacks provide the additional requirement
for high replenishment rates to maintain consistent results.
[0003] With the growth of laser imaged products, the operating environment is shifting from
high capacity darkroom based machines, capable of processing a wide range of silver
halide media, towards smaller, possibly dedicated machines able to operate under white
light in an office-like environment.
[0004] There are a number of known examples of coating processes using a slot- or slit-like
arrangement. An example of a slot type is commonly used for precision coating of photographic
emulsions, for single and multi-layer applications. However, these are precision slots
with a gap width of about 0.5mm and operate by supplying solution to the moving web
at the same rate at which it is pumped. Another slit applicator was developed by Fairchild
for the U.S. Navy (PS&E Vol 5 1961). This consisted of a 70mm applicator head through
which film passed to be treated. The viscous solution was fed into and retained within
a slotted undercut which then coated the solution onto the emulsion as the film was
pulled through.
[0005] US-A-3 372 630 and US-A-5079580 describe another group of coaters which have been
described as slot coaters and which operate by a principle which requires passing
the film through a narrow slit. The general arrangement of the applicators allows
a narrow slit to be filled with solution which is transferred to the film as it is
passed through the slit. Several configurations exist which are claimed to assist
the uniformity of application and improve agitation. All of this group rely on passing
the film through the orifice rather than over the top of the slit. Another variation
along these lines is disclosed in US-A-5043756 which makes use of a double walled
'U' shaped tank of low internal volume, through which the film is passed to effect
processing.
[0006] EP-A-525 886 discloses an applicator which consists of a slit orifice composed of
a plurality of channels. The applicator has an integral manifold which distributes
solution equally down the narrow channels which is then deposited onto the receiving
film. In effect the delivery is made from a multitude of individual streams running
down each channel, which then coalesce to form a continuous layer onto the film. There
is no provision for the collection of solution overflow.
[0007] GB-821031 discloses apparatus for the application of liquid to the surface of a material
comprising a processing head having a trough or recess provided with an inlet and
an outlet opening for processing liquid, means for maintaining the material spaced
at a short distance from the edges of the trough or recess, a reservoir for processing
liquid, and means for applying suction to the trough or recess, through the outlet
opening so that liquid in the reservoir can be drawn to the trough or recess while
air is drawn into the trough or recess through the space between the trough or recess
and the said material. The air layer formed by the suction is essential in obtaining
turbulent flow in the processing head which ensures effective processing.
[0008] GB-2209228 discloses a system for the development of exposed silver halide film in
which the film moves emulsion side up on conveyor, a viscous developer is applied
to the film by gravity from a feeder with a series of openings located above a container
and the moving film close to one end of the conveyor, blade is provided adjacent the
other end to remove excess unused developer, and squeegee rollers squeeze used developer
off the film before rinsing and fixing the developed film. The developer may be applied
via a narrow slit at the bottom of the container, where the slit is perpendicular
to the direction of movement of the film. The uniformity of the development layer
is attained by roof sections and above the moving film, the space being filled with
developer by controlling the rate of supply of the developer and the distance between
the roof sections and the conveyor.
[0009] US-A-4281620 discloses an applicator provided with a plurality of slots extending
traversely to the direction of paper movement. The fluid is circulated from one slot
to the next one along a sinuous path. Excess fluid not carried away by the processed
paper is collected by the applicator.
BRIEF DESCRIPTION OF THE INVENTION
[0010] This invention relates to a novel method for processing imagewise exposed photosensitive
media based on silver halide, in the form of films, papers, printing plates, etc.
In a first aspect of the invention, there is provided a process for the application
of liquids to photosensitive elements in accordance with claim 1.
[0011] The invention also provides an apparatus for applying solutions to photosensitive
media as defined by claim 8. An insert may be present within said slot, said insert
providing a rounded surface which faces said photosensitive element in contact with
solution within said slot. The means for removing solution from the slot may direct
the removed solution back to the reservoir, or to a separate collection means, and
preferably is switched between these modes.
[0012] The processing step is carried out by transporting the photosensitive media across
a coating head, the key component of which is a slot. Processing solutions are pumped
to, and drained from the slot in the coating head. In normal operation, aspects of
the design and pump rate of processing solutions to the slot allow a continuous and
continuously replenished (or replaced) bead of the solution to form evenly along the
entire length of the slot. Solution removed from this bead is imbibed by the medium
and is used to process the photosensitive element.
[0013] The apparatus is suitable for all the stages of conventional silver halide processing,
such as activated development, development, fixation, bleaching, and stabilisation.
It is possible, but less efficient to perform a washing step by this process. Processing
using the apparatus described in this invention provides many advantages over conventional
tank processing, including reduced atmospheric exposure of chemistry, low volume usage
of processing solutions, efficient agitation of solutions at the point of application
of solutions at the slot and reduced unit costs for the processor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
Figure 1 is a sectional, isometric elevation of a slot coater; and
Figure 2 is a side cutaway view of the slot coating device and reservoir according
to the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] This device of the invention can be used to treat any photographic material with
liquid chemicals during the development, fixing, washing, activating and stopping
process. Liquid solutions such as developers, fixers, wash water and activators can
be applied to the photosensitive layer at the appropriate stage of processing via
one or more applicator heads. The applicator heads are associated with suitable transport
rollers which guide the film across the heads, following a suitable path which allows
the film to make intimate contact with the top face of each head. The transport system
also allows film to pass through at a constant rate over each coating head in turn
through the entire process. A limited and controlled application of solution is made
at each head which effects a thin coating of solution over the photosensitive layer.
[0016] A separate applicator head may be provided for the application of each of the different
solutions required in the various stages in the processing of the film, the device
thus comprising a series of applicator heads spaced apart by a distance sufficient
to enable each stage of the processing cycle to proceed to completion before the relevant
portion of the film arrives at the next applicator head. The spacing required will
obviously depend on the rate at which the film is transported through the device,
and both the spacing and the transport rate may be adjustable to suit different circumstances.
Two or more consecutive applicator heads in the series may be dedicated to the same
stage of the processing cycle (e.g., development), which may enable a faster throughput.
[0017] Optionally, one or more applicator heads in accordance with the invention may be
used to effect only part of the processing cycle (e.g., development only, or development
and fixing), with the remainder being accomplished by conventional means such as bath
processing, spraying etc.
[0018] Because of the simplicity of the system, the process is applicable to many different
dimensions of media, e.g., of up to 200mm in width. To ensure even distribution of
liquid over the surface of the media and even replenishment at the application zone
of liquid to the media, conventional fluid mechanics and design considerations may
be applied to the apparatus. For example, the slot may be wider at its edge portions
than in the centre to ensure even flow of liquid to the edges of the media at the
application point or within the application zone. Alternatively, or additionally,
a manifold may be used to supply liquid evenly to the entire length of the slot.
[0019] It is desirable to pump slightly more liquid (e.g., activator solution) into the
slot than is actually absorbed or imbibed by the medium. This ensures that there will
always be sufficient liquid within the application zone to meet the demands of the
system. Surplus solution may be recycled into the reservoir by collection in drains,
the overflow or excess liquid of such drains being directed to the reservoir. This
overflow liquid is minimally contaminated by contact with the medium, but if contamination
is detected, and that contamination at any time is excessive, or if the composition
within the reservoir is not in proper chemical balance, the solution in the overflow
may be directed away from the reservoir for separate replenishment, cleaning or disposal.
[0020] Certain measures are desirably taken to promote good and uniform contact of the film
with the applied solution. Film should move in a path which is arcuate (i.e., convex
towards the slot coater) to keep pressure against the slot or the surface of the housing
which defines the slot. By having the leading edge or plane of the film strike the
surface in advance of the slot while maintaining a convex profile, the required pressure
is maintained. This helps to ensure effective contact of the medium in the slot application
area. A slip coating can be provided on the surface of the housing in advance of the
slot, to ensure smooth movement and non-abrasion of the film. Films of polytetrafluoroethylene
and other slip materials are useful for that purpose.
[0021] There may also be a slot insert which can be present in the slot to ensure that the
flow of liquid in the application zone is properly controlled. The insert can be a
bar or semi-cylindrical bar with the rounded end facing upward (towards or into the
slot). The insert may contain absorptive or carrier material to wick or support liquid
at the point of application (e.g., gauze, reticulated foam, mesh, etc.).
[0022] The processes of the present invention are particularly suitable for use in the application
of activator or "spiked" activator solutions to silver halide imaging media such as
diffusion transfer imaging media as disclosed in U.S. Patent Nos. 4,062,041 and 4,784,933.
These activator solutions are relatively high pH solutions (pH greater than 9.0 up
to 12.5 or higher) which, in the case of spiked activators, also contain some developer
in the activator solution. The process and apparatus are also found to be useful not
only for activators, but also for other active solution applications. The process
and apparatus of the present invention are particularly useful for activator systems
because of the fact that activators need to be in contact with the imaging medium
for only a brief period of time as compared to developer solutions or other active
solutions.
[0023] The applicators of the present invention are also very useful for applying fixer
solution. Systems have been used where the fixer solution is applied in a straight
line arrangement after application of the activator. Conventional processing units
generally have series of rollers which direct the film in turns of about 90 and 180
degrees towards the various baths or applicators. In straight line processing, as
in the present invention, the film need not ever be turned more than 90 degrees, preferably
not more than 50 degrees, more preferably no more than 40 degrees, and most preferably
less than 20 degrees between any two solution applications, particularly between the
activator and fixing applications.
[0024] Silver halide systems which are particularly susceptible to development with the
process and apparatus of the present application include diffusion transfer systems
(for which activator developing systems are well known), and graphic arts media (particularly
those with high silver chloride content, such as greater than 75% AgCl, more preferably
greater than 80% AgCl, and most preferably greater than 90% and up to 100% AgCl).
[0025] The process and apparatus of the present invention can also provide other benefits
towards reducing the amount of solutions which need to be used in the processing of
given amounts of media. It is readily possible to heat the solution immediately before
application, and the heating may be performed on only those amounts needed for delivery.
In a preferred embodiment, the amount of heated solution is the amount imbibed by
the media and some modest overflow which is returned to the reservoir.
[0026] In conventional bath or tank processors, the entire volume of processing solution
must be continuously maintained at the working temperature, and so higher working
temperatures lead to higher energy costs. Moreover, photographic processing solutions
(especially developer solutions) are known to deteriorate rapidly if held at high
temperatures for extended periods. In the apparatus of the invention, only a minimal
volume of solution is heated at any one time, and a given volume of solution is held
at elevated temperatures for only a short time, e.g., a few seconds. Hence, energy
costs arising from heating the solutions are low, and the risk of accelerating the
decomposition of processing solutions is minimised. For these reasons, it is possible
to carry out the processing at higher temperatures than would normally be possible
using conventional equipment, and hence gain an increase in throughput. Because lower
volumes of liquid are applied, there is less potential for excessive softening of
gelatin layers by the heat content of the applied solution, as could occur in a heated
immersion bath. A cooling device (such as a Peltier element) may also be used on the
means for returning overflow or excess to the reservoir so that heated liquid is not
returned to the reservoir.
[0027] The invention is hereinafter described in more detail by way of example only with
reference to the accompanying drawings in which:
[0028] Figure 1 shows a basic slot coating apparatus 1, comprising a frame (or housing)
3 having an upwardly facing slot 5. Film (or photosensitive element) 13 which is to
be treated with solution (arrow 29) is directed by nip rollers 15 and a guide roller
17 against an advance surface 9 of the frame 3 in advance of the slot 5. As shown
in Figure 1, the film is arcuate as it approaches the advance surface 9, and describes
a path which is convex towards the apparatus 1. The solution (or liquid) 29 enters
the slot coater 1 through a duct 33 and exits the slot coater through a duct 31. The
materials used for construction must be inert to any solutions used and possess sufficient
mechanical strength to maintain the integrity of the assembly.
[0029] In the assembled form the construction can be divided into three sections: solution
feed, coating, and solution drain. Solution 29 is fed into one side of the head 1,
forced up to the slot 5 evenly doing the length of the slot where the coating takes
place and any excess solution drained away from the opposite side. The coater head
1 contains two ducts (23, 25) or nozzles (not shown) for input and output of solution,
situated in the lower half of the body 1. Solution 29 fed into the input side via
a pump 21 may enter a manifold (not shown) before being fed up to the slot 5.
[0030] The slot 5 itself is a gap of some 1-15 mm (e.g., 5mm), although a range of 3-10mm
is preferred, which may have a length equal to the entire width of the coater and
is capable of coating film up to a maximum width dimension equal to this length. Situated
below the slot 5 in Figure 2 is a semicircular bar insert 7 which is also about as
wide as the slot 5. Solution 29 fed up from the manifold (not shown) is directed up
and over the insert 7, following its profile.
[0031] In another embodiment of the invention the semicircular bar 7 is replaced with a
circular bar (not shown). This also would be located into a slot of width just large
enough to accommodate the bar and deep enough to seat the bar down sufficiently so
as to produce a similar profile to that of the semicircular insert 7.
[0032] Due to the close proximity of the insert 7 and slot 5, solution fills the gap creating
a lengthwise bead of liquid (not shown). The gaps between the bar insert and the edges
of the slot 5 are adjustable to allow production of the desired bead in the slot for
a range of solution viscosities and flow-rates. The bar 7 may be adjusted by altering
the height of two adjustable screws (not shown), one at each end, on which the bottom
of the bar sits. A typical operating range of gap width is 0.1 - 2.0mm. At the back
edge 35 of the slot 5, between the rear portion of the top plate 11 and insert 7,
is a gap 37 which allows solution 31 to drain away to a shallow trough 27 in which
a small amount of solution (not shown) can collect. From here the liquid may drain
away via outlet nozzle(s) 25, either by pumping or by action of gravity. This used
solution 31 can be either returned to the feedstock reservoir 19, or go to waste disposal
(not shown).
[0033] The drive system for the film is via a suitable set of (e.g., rubber faced) rollers
15 of the type used in conventional processing systems. These are arranged on each
side of the coating head 1 to provide a feed and take-up of the film 13 over the head.
In addition to the rollers 15 some appropriate fixed guides (not shown) may be required
to achieve the correct feed path on to and off the head. Two pairs of driven pinch
rollers 15 are the minimum requirement for each slot, although for multiple slot systems
(not shown) a pair of rollers between slots can be shared by both applicators. The
path length between rollers is required to be somewhat shorter than the minimum length
of film to be processed, allowing the take-up rollers to grip before the feed pair
let go.
[0034] The film 13 is fed with the photosensitive layer (not shown) facing down so that
this side makes contact with the solution in the slot 5. In one embodiment, rollers
guide the lower side of the film (usually the side which is to be treated, i.e., the
photosensitive side) down initially, bending the film medium such that it is in compression.
The film is then re-directed by rollers and guides so that the lower side of the film
is now in compression such that on reaching the front edge 9 of the coating head there
is a slight force (elastic recovery) which holds the sheet down onto the top of the
head. The exit side of the head can be of a very similar arrangement to the entry
side, although an additional roller is required to hold the film onto the head towards
the back edge.
[0035] The path followed by the film as it passes over the coating head(s) is essentially
horizontal, with the side to be treated with processing solution facing downwards,
although some deviation in either direction can be tolerated. However, it will be
appreciated that the further the coating leads themselves are tilted from the horizontal,
the greater will be the risk of leakage of processing solution.
[0036] The action of the bead which forms in the slot is such that a thin layer of solution
forms between the head and film. Capillary action forces some solution back towards
the front edge and by the dragging action of the moving film a thin layer is also
produced after the slot. The combined effect of the different stages produces a film
which is coated with a thin layer of solution. This layer remains on the surface until
removed by either a squeegee action of a roller pair or displaced by a later treatment.
[0037] The supply rate of solution to the slot is an important parameter and is directly
related to the film transport speed over the head for optimum coating performance.
In order that a film be properly processed a certain minimum quantity of solution
is required, namely the volume taken up by the gelatin plus the layer carried away
on the film surface. The solution supply rate in conjunction with the film transport
speed must at least satisfy this minimum requirement. For best results it is necessary
to supply at a rate somewhat greater than the minimum required. The excess supplied
overruns into the drain to be recycled. Typical pumping rates are in the region of
10-50cc/100mm of slot at a film transport speed of 3-6mm/sec. Pumping need only be
initiated just prior to the arrival of the leading edge of the film and cease as the
back edge leaves the slot region. This feature helps with reducing atmospheric oxidation
as no solution is in contact with the surrounding air whilst the pumps are inoperative.
Timing of the pump duty cycle can be achieved by the placement of suitable film detectors
just prior to the coating head, which will allow for a suitable priming time of the
slot with solution before the arrival of the film.
[0038] Temperature is a very important parameter in photographic processing and requires
close control to obtain consistent results. The slot applicator has a major advantage
in this respect over conventional tank processors in that solution can be brought
up to the required temperature within the body of the head. This means that the solution
is heated as required just prior to application to the photographic film. This in
turn provides for a much longer chemistry life, as large tanks of developer and activator
held at elevated temperatures suffer from rapid oxidation. Electrical heating elements
(not shown) are installed into the delivery manifold region to provide the heat energy
and are controlled via temperature sensors near the slot. Alternatively a heat exchanging
system could be employed in which heated solution (e.g., water) be pumped through
the body of the head, totally separated from the photographic solutions. The heat
energy given out by the water heats the head body which in turn heats the photographic
solutions. In the latter example it would be beneficial if a substantial portion of
the head body be made from a good thermal conductor (e.g., metal or some ceramics)
to assist the process of heat transfer and to provide a thermal mass, which will help
to even out minor temperature fluctuations. In the case of high temperature processing
(greater than 35°C) an advantage may be gained by part heating the solution to some
intermediate temperature, at which atmospheric oxidation rates are low, and then to
bring the solution up to the desired temperature in the body of the head, by the means
already described.
[0039] In a further embodiment, the circular insert is covered with a layer of meshed material
so that the outer surface which comes into contact with the processing solutions is
completely covered. Such an addition effectively increases the diameter of the bar,
which then requires re-adjustment to restore the original slot gaps, although the
highest point of the insert is still below the level of the film plane during operation.
The effect of the mesh is to wick the solution across the gap width and assist in
the even distribution of solution onto the film during the coating process. Because
of the high surface area of the mesh, it has water attracting properties which assist
in stabilising the bead which forms. The mesh material must be compatible with the
solutions being used e.g., stainless steel, polyester and nylon are good examples,
but by no means the only suitable candidates. Mesh sizes may influence the effectiveness
of addition. A range of 0.787-7.87 counts/mm (20-200 counts/inch) is the most appropriate.
[0040] To operate as a complete system at least one slot coater is required for each of
the chemical treatment stages of processing. Should any stage require additional treatment,
two or three slot coaters could be arranged in series to provide for this. It is also
envisaged that a slot coater could be used within a system which uses conventional
bath processing, replacing one or more of the processing stages with a slot coater.
Examples
[0041] The example apparatus included a suitable transport system to guide the film over
the slot at constant rate: speed adjustable from 2.5 to 17.0 mm/s. The pumps used
to deliver and drain the solutions were of the peristaltic type which were connected
to the slot coater via poly(vinyl chloride) tubing, a separate circuit being used
for solution delivery and drain. Flow rate to the slot was controlled from the pump
and was set at a rate which allowed for the formation of a continuous bead across
the width of the slot. Prior to processing, the delivery lines were primed by pumping
until solution could be seen to be forming at the slot and the tubing was free of
air bubbles. Once primed, the coater could be left in this state ready to receive
film material.
[0042] The operation of the pumps was controlled manually, although such a system is ideally
suited to full automation with appropriate sensors to detect film location relative
to the slot. A sheet of photographic film to be processed was fed into the first set
of pinch rollers and fed down to the slot. Just prior to the film reaching the slot
the delivery pump was activated, closely followed by the drain pump. Both pumps were
left operating until the back edge of the film left the slot region, whereupon both
were switched off. The same procedure was adopted no matter which stage of the processing
cycle was being performed.
[0043] Due to the short processing times required the slot coater is particularly suited
to activated processing; high pH solution being used to trigger development from a
layer coated under the emulsion which carries the developer. A small quantity of activator
of high pH uniformly applied is sufficient to trigger development and process to a
suitable image density. Photographic emulsions of a composition high in chloride and
low in bromide have particularly short processing times (< 5 seconds) and may be processed
to full density by passing over the slot at a rate of ∼10mm/s and a supply rate of
50cc/min. In this example the activator was not recycled, i.e., only fresh solution
was supplied to the slot. Fixing and washing was by conventional bath process. Repeated
tests over 10 separate sheets of exposed film produced the following results:
|
Avg |
SD |
D-min |
0.061 |
0.007 |
Sp-1 |
1.975 |
0.018 |
Sp-2 |
1.858 |
0.017 |
Sp-3 |
1.597 |
0.014 |
TH-1 |
0.698 |
0.039 |
TH-2 |
1.541 |
0.086 |
TH-3 |
5.95 |
0.31 |
Con-1 |
3.99 |
0.118 |
Con-2 |
2.99 |
0.45 |
D-Max |
4.141 |
0.104 |
Sp-1 speed point measured at 0.1 + dmin
Sp-2 speed point measured at 0.2 + dmin
Sp-3 speed point measured at 1.0 + dmin
TH-1 contrast (gradient) between points 0.07 + dmin and 0.17 + dmin
TH-2 contrast between 0.17 + dmin and 0.37 + dmin
TH-3 contrast between 0.50 + din and 2.50 + dmin
Con-1 contrast (gradient) between points 0.1 + dmin and 2.5 + dmin
Con-2 contrast (gradient) between points 1.6 and 4.0 absolute density |
[0044] These sensitometric data compare well with those obtained from bath processing.
[0045] In the case of emulsions which have a higher bromide content, processing times are
increased to allow for the reduced rate of development. A typical emulsion used for
laser scanning applications may have a bromide content of 35%. To achieve full development
with these emulsions, coated with the developer incorporated underlayer, and again
using a high pH activator processing, speeds as low as 4mm/sec are necessary to produce
full development, with activator pump rates of 50mls/min.
Developer processing
[0046] In this example, a standard developer solution (DRC-V developer solution from Imation
Corp., Oakdale, MN -- formerly a portion of 3M Company, St. Paul MN) was applied to
an exposed conventional film (DRC-P film from Imation Corp., Oakdale, MN -- formerly
a portion of 3M Company, St. Paul MN). Due to the longer processing times necessary
the film transport speed of 5mm/s was used at developer delivery rates of 50mls/min.
At 25°C a single pass produced a D-max of about 1.5, compared to the standard of 4.5
processed conventionally. Passing a piece of film over the head twice gave a value
of 3.7, i.e., still under developed. Heating the developer to 38°C gave a D-max of
about 4.0 with a single pass whilst concentrating the developer by not diluting 1+4
with water gave about 2.8 with a single pass and 4.42 with two passes, both at 35°C.
From this it can be concluded that a more concentrated developer solution running
at the correct temperature (35°C) is capable of achieving a performance close to the
standard by a double pass over the head. This mimics a single pass over two heads
in series.
1. A process for the application of a liquid (29) to a photosensitive element (13) comprising
the steps of:
providing a coating head (1) with a housing (3) having a top plate (11) defining a
generally upwardly facing slot (5) therein,
providing a liquid (29) within the slot 5 evenly along its length;
continuously moving said photosensitive element (13) facing generally downwardly over
the slot (5) and contacting the element (13) with the liquid (29) within the slot
(5), such that
the photosensitive element (13) is removed from the slot (5) with liquid (29) in or
on the element (13), wherein the amount of liquid (29) provided to the slot (5) is
more than the amount of the liquid (29) carried away from the slot 5 by the element;
and
providing means within the housing for collecting the excess liquid (29) from the
slot (5).
2. The process according to claim 1 wherein the liquid (29) is an activator liquid for
silver halide development and said photosensitive element (13) is a silver halide
photosensitive element with a silver halide emulsion on a support, the emulsion being
positioned between the support and the slot (5) when said photosensitive element (13)
contacts said liquid (29) within the slot (5).
3. The process according to claim 1 wherein an insert (7) is present within the slot
(5), and said liquid (29) moves over the insert (7).
4. The process according to claim 3 wherein the insert (7) has a rounded surface which
faces said photosensitive element (13).
5. The process according to claim 1 wherein the photosensitive element (13) is bent to
hold the element (13) in contact with the coating head (1).
6. The process according to claim 1 wherein the amount of said liquid (29) provided to
the slot (5) is no more than twice the amount of said liquid (5) carried away by the
element (13) when leaving the slot (5).
7. The process according to claim 6 wherein the amount of said liquid (29) delivered
to the slot (5) is less than 120% the amount of said liquid (29) carried away by the
element (13).
8. An apparatus (1) for applying liquids to a photosensitive element (13) comprising:
a coating head (1) comprising a housing (3) having a top plate (11) defining a generally
upwardly facing slot (5),
means within the housing (3) for providing liquid (29) to the slot (5) evenly along
its length;
transport means for transporting the photosensitive element to said slot (5) and placing
said photosensitive element (13) in contact with liquid (29) within said slot (5),
and for transporting the photosensitive element (13) away from the slot (5) with liquid
(29) therein or thereon; and
means within the housing (3) for removing excess liquid (29) from said slot (5).
9. The apparatus (1) according to claim 8 additionally comprising an insert (7) positioned
within said slot (5), said insert (7) having a rounded surface which faces said photosensitive
element (13) in contact with said liquid (29) within said slot (5).
10. The apparatus (1) according to claim 8 additionally comprising:
a reservoir (19), wherein said means for removing liquid (29) carries liquid (29)
removed to said reservoir (19);
heating means for heating said liquid (29) prior to said liquid (29) reaching said
slot (5); and
cooling means for cooling excess liquid (29) removed from said slot (5).
1. Verfahren zum Auftragen einer Flüssigkeit (29) auf ein photosensitives Element (13)
mit den folgenden Schritten:
Bereitstellen eines Beschichtungskopfs (1) mit einem Gehäuse (3), das eine Deckplatte
(11) hat, die einen allgemein nach oben weisenden Schlitz (5) darin bildet,
Bereitstellen einer Flüssigkeit (29) innerhalb des Schlitzes (5) gleichmäßig über
seine Länge;
kontinuierliches Bewegen des allgemein nach unten weisenden photosensitiven Elements
(13) über den Schlitz (5) und In-Berührung-bringen des Elements (13) mit der Flüssigkeit
(29) innerhalb des Schlitzes (5), so daß das photosensitive Element (13) mit Flüssigkeit
(29) in oder auf dem Element (13) vom Schlitz (5) entfernt wird, wobei die zum Schlitz
(5) geführte Menge von Flüssigkeit (29) größer als die durch das Element vom Schlitz
(5) abgeführte Menge der Flüssigkeit (29) ist; und
Bereitstellen einer Einrichtung innerhalb des Gehäuses zum Auffangen der überschüssigen
Flüssigkeit (29) aus dem Schlitz (5).
2. Verfahren nach Anspruch 1, wobei die Flüssigkeit (29) eine Aktivatorflüssigkeit zum
Silberhalogenidentwickeln ist und das photosensitive Element (13) ein photosensitives
Silberhalogenidelement mit einer Silberhalogenidemulsion auf einem Träger ist, wobei
die Emulsion zwischen dem Träger und dem Schlitz (5) positioniert ist, wenn das photosensitive
Element (13) die Flüssigkeit (29) innerhalb des Schlitzes (5) berührt.
3. Verfahren nach Anspruch 1, wobei ein Einsatz (7) innerhalb des Schlitzes (5) vorhanden
ist und sich die Flüssigkeit (29) über den Einsatz (7) bewegt.
4. Verfahren nach Anspruch 3, wobei der Einsatz (7) eine abgerundete Oberfläche hat,
die zum photosensitiven Element (13) weist.
5. Verfahren nach Anspruch 1, wobei das photosensitive Element (13) gebogen wird, um
das Element (13) mit dem Beschichtungskopf (1) in Berührung zu halten.
6. Verfahren nach Anspruch 1, wobei die Menge der Flüssigkeit (29),- die zum Schlitz
(5) geführt wird, höchstens doppelt so groß wie die Menge der Flüssigkeit (29) ist,
die durch das Element (13) beim Verlassen des Schlitzes (5) abgeführt wird.
7. Verfahren nach Anspruch 6, wobei die Menge der Flüssigkeit (29), die zum Schlitz (5)
geführt wird, weniger als 120 % der Menge der Flüssigkeit (29) beträgt, die durch
das Element (13) abgeführt wird.
8. Vorrichtung (1) zum Auftragen von Flüssigkeiten auf ein photosensitives Element (13)
mit:
einem Beschichtungskopf (1) mit einem Gehäuse (3), das eine Deckplatte (11) hat, die
einen allgemein nach oben weisenden Schlitz (5) bildet;
einer Einrichtung innerhalb des Gehäuses (3) zum Zuführen von Flüssigkeit (29) zum
Schlitz (5) gleichmäßig über seine Länge;
einer Transporteinrichtung zum Transportieren des photosensitiven Elements zum Schlitz
(5) und Plazieren des photosensitiven Elements (13) in Berührung mit Flüssigkeit (29)
innerhalb des Schlitzes (5) sowie zum Wegtransportieren des photosensitiven Elements
(13) vom Schlitz (5) mit Flüssigkeit (29) darin oder darauf; und
einer Einrichtung innerhalb des Gehäuses (3) zum Entfernen von überschüssiger Flüssigkeit
(29) aus dem Schlitz (5).
9. Vorrichtung (1) nach Anspruch 8, zusätzlich mit einem innerhalb des Schlitzes (5)
positionierten Einsatz (7), wobei der Einsatz (7) eine abgerundete Oberfläche hat,
die zum photosensitiven Element (13) weist, das mit der Flüssigkeit (29) innerhalb
des Schlitzes (5) in Berührung steht.
10. Vorrichtung (1) nach Anspruch 8, zusätzlich mit:
einem Reservoir (19), wobei die Einrichtung zum Entfernen von Flüssigkeit (29) entfernte
Flüssigkeit (29) zum Reservoir (19) führt;
einer Erwärmungseinrichtung zum Erwärmen der Flüssigkeit (29), bevor die Flüssigkeit
(29) den Schlitz (5) erreicht; und
einer Kühleinrichtung zum Kühlen von überschüssiger Flüssigkeit (29), die aus dem
Schlitz (5) entfernt wird.
1. Procédé d'application d'un liquide (29) sur un élément photosensible (13), comprenant
les étapes consistant à :
◆ prévoir une tête d'enduction (1) comportant un boîtier (3) possédant une plaque
supérieure (11) définissant en elle une fente (5) tournée d'une manière générale vers
le haut,
◆ introduire un liquide (29) à l'intérieur de la fente (5) et ce d'une manière uniforme
sur toute la longueur de cette dernière;
◆ déplacer continûment ledit élément photosensible (13) tourné d'une manière générale
vers le bas, au-dessus de la fente (5) et placer en contact l'élément (13) avec le
liquide (29) à l'intérieur de la fente (5) de telle sorte que
◆ l'élément photosensible (13) est retiré de la fente (5) avec le liquide (29) dans
ou sur l'élément (13), la quantité de liquide (29) envoyée à la fente (5) étant supérieure
à la quantité de liquide (29) entraînée à partir de la fente (5) par l'élément ; et
◆ prévoir, à l'intérieur du boîtier, des moyens pour collecter le liquide en excès
(29) à partir de la fente (5).
2. Procédé selon la revendication 1, selon lequel le liquide (29) est un liquide activateur
pour le développement d'un halogénure d'argent, et ledit élément photosensible (13)
est un élément photosensible à halogénure d'argent comportant une émulsion d'halogénure
d'argent sur un support, l'émulsion étant positionnée entre le support et la fente
(5) lorsque ledit élément photosensible (13) vient en contact avec ledit liquide (29)
à l'intérieur de la fente (5).
3. Procédé selon la revendication 1, selon lequel un insert (7) est présent dans la fente
(5) et ledit liquide (29) se déplace au-dessus de l'insert (7).
4. Procédé selon la revendication 3, selon lequel l'insert (7) possède une surface arrondie
qui est tournée vers ledit élément photosensible (13).
5. Procédé selon la revendication 1, dans lequel l'élément photosensible (13) est cintré
de manière à maintenir l'élément (13) en contact avec la tête d'enduction (1).
6. Procédé selon la revendication 1, selon lequel la quantité dudit liquide (29) envoyée
à la fente (5) n'est pas supérieure au double de la quantité du liquide (5) évacuée
par l'élément (13) lorsqu'il quitte la fente (5).
7. Procédé selon la revendication 6, selon lequel la quantité du liquide (29) envoyée
à la fente (5) est inférieure à 120 % de la quantité de liquide (29) évacuée par l'élément
(13).
8. Dispositif (1) pour appliquer des liquides à un élément photosensible (13), comprenant
:
◆ une tête d'enduction (1) comprenant un boîtier (3) possédant une plaque supérieure
(11) définissant une fente (5) tournée d'une manière générale vers le haut;
◆ des moyens situés dans le boîtier (3) pour amener un liquide (29) à la fente (5),
d'une manière uniforme sur la longueur de cette dernière;
◆ des moyens de transport servant à transporter l'élément photosensible jusqu'à ladite
fente (5) et placer ledit élément photosensible (13) en contact avec le liquide (29)
à l'intérieur de ladite fente (5) et pour écarter l'élément photosensible (13) de
la fente (5) avec le liquide (29) situé dans ou sur cet élément photosensible; et
◆ des moyens situés à l'intérieur du boîtier (3) pour retirer le liquide en excès
(29) de ladite fente (5).
9. Dispositif (1) selon la revendication 8, comprenant en outre un insert (7) positionné
à l'intérieur de ladite fente (5), ledit insert (7) possédant une surface arrondie
qui est tournée vers les éléments photosensibles (13) en étant en contact avec ledit
liquide (29) situé dans ladite fente (5).
10. Dispositif (1) selon la revendication 8, comprenant en outre :
◆ un réservoir (19), dans lequel lesdits moyens pour retirer le liquide (29) entraînent
le liquide (29) retiré en direction dudit réservoir (19);
◆ des moyens de chauffage pour chauffer ledit liquide (29) avant que ledit liquide
(29) atteigne ladite fente (5); et
◆ des moyens de refroidissement pour refroidir le liquide en excès (29) retiré de
ladite fente (5).