Photographic developer

A photographic developer for sheet film arranged to feed the film through two or more interconnected chambers sealed by seals at the inlet of the first chamber and the outlet of the final chamber and also sealed at the interconnection of the chambers by means of seals which are preferably rotatable and controlled by a single motor, the seals preferably having rotatable valves at one end which control the inlet and outlet of developing and fixing agents as well as a drying gas.

The present invention relates to photographic developers for developing and 
fixing film. 
High speed photographic cameras, particularly microfiche cameras, are 
capable of exposing film at increasingly high rates and the corresponding 
provision of high speed developing units therefore becomes very important. 
According to the invention a photographic developer is provided with a 
first chamber and a second chamber in intercommunication with the first 
chamber and separated therefrom by a fluid seal, the first chamber having 
an inlet seal and the second chamber having an outlet seal, the chambers 
having fluid inlets and outlets for continuously feeding fluids 
therethrough. 
Preferably, the first chamber is above the second chamber and is aligned 
therewith so that a film being developed may be fed downwards from chamber 
to chamber past the fluid seal. 
In one preferred embodiment that are fluid inlets and outlets on both sides 
of the chambers, and the inlet to the first chamber is sealed by a pair of 
rollers. 
According to another aspect of the invention a method of developing film 
comprises feeding exposed photographic film through an inlet seal into a 
first chamber in intercommunication with a second chamber separated from 
the first chamber by a fluid seal, passing a developer through the first 
chamber, washing the film, fixing the film in the second chamber, further 
washing the film, and drying the film. 
Preferably, the film is washed in the first chamber after developing and 
the film is dried in the second chamber by emptying the second chamber and 
passing a drying gas around the film. Alternatively, drying can be carried 
out in a further chamber interconnected to the second chamber. 
Alternatively the developing and fixing process may be carried out in the 
first chamber whilst using the second chamber for washing and drying the 
film. 
In a further embodiment the seals at either end of the chambers which are 
constructed so as to be rotatable by one or more motors, which motor or 
motors synchronously drive valve assemblies for controlling the feed of 
liquid into the chambers. 
In a further embodiment the liquid seals comprise a first rotatable gate in 
an entry to a first chamber in which developing and fixing may be carried 
out, a second rotatable gate between an exit to the first chamber and an 
entry to a second chamber in which washing may be carried out, and a third 
rotatable gate in an exit to the second chamber. 
In a further embodiment the third rotatable gate only acts as a film seal 
since liquid is allowed to by-pass the third gate for drainage purposes. 
Development of the film may be carried out by means of a liquid born 
developing agent, or a gas born developing agent. 
Furthermore, it is possible to use a gas born fixing agent or a liquid born 
fixing agent. 
The advantages of using gas born developing and fixing agents in the 
developers according to the invention is that the drying by means of a 
drying gas may be carried out in a shorter time than when liquid born 
developing and fixing agents are used.

In FIG. 1 there is shown a first or upper developing chamber 1 and a second 
or lower fixing chamber 2, both of which are aligned and in 
intercommunication with each other, but separated by a liquid seal 3 
formed by two intercooperating leaves 4. At the upper end of the 
developing chamber 1 an inlet seal is formed by two resilient rollers 5 
which, apart from sealing the upper end of the developing chamber, assist 
in feeding a film 6 into the developing chamber. At the lower end of the 
fixing chamber 2 an outlet seal 7 is provided which is similar to the 
liquid seal 3. The developer chamber 1 has inlets 8 provided on both sides 
and outlets 9 also on both sides. Similarly, the fixing chamber 2 has, on 
both sides, inlets 10 and outlets 11. Interconnecting the inlets and 
outlets of the developer chamber 1 is a recirculating duct 12 which can be 
opened or closed by means of a valve 13. Similarly, the fixing chamber 2 
is provided with a recirculating duct 14 controlled by a valve 15. Drain 
valves 16 and 17 are provided for the outlets 9 and 11 of the chambers 1 
and 2 respectively, for closing the drains when the recirculating valves 
13 and 15 are open. A developer insert valve 18 is provided at the upper 
end of the developing chamber, together with a water inlet valve 19. At 
the inlet to the fixing chamber there is provided a fixer insert valve 20, 
a water inlet valve 21, a check valve 22 and an air inlet valve 23. In 
order to assist recirculation, pumps 24 and 25 are provided in the 
recirculating ducts 12 and 13 respectively. 
To operate the developer, water is passed through the upper chamber 1 with 
valves 19 and 16 open and 18 and 13 closed. At the same time water is 
passed through the lower chamber 2 through valves 21 and 17 with valve 22 
open and valves 20, 23 and 15 closed. The water pressure at valves 19 and 
21 is at the water mains pressure. A film 6 is then inserted into the 
upper chamber by rotation of the rollers 5 and valve 13 is opened at the 
same time as valves 19 and 16 are closed. The recirculating pump 24 is 
operated and developer is metered through valve 18 so that developer is 
now circulated through the upper chamber 1 on both sides of the film 6, 
which is supported clear of the sides of the chamber by the flow of 
developing liquid. Developing then continues at a controlled temperature 
with a controlled concentrate of developing liquid for a predetermined 
time. Each of these parameters can be adjusted to achieve the correct 
development. 
When developing is near completion recirculation by means of pump 24 is 
stopped, valve 19 is opened and the developer is purged through valve 16. 
The film is then washed for a given time until the seal is opened, 
allowing the film 6 to float into the lower chamber 2. 
Entry into the lower chamber 2 is suitably monitored by means of a light 
projecting through the walls of the chamber 2 and operating a 
photoelectric cell. 
On entry to the lower chamber 2 the liquid seal 3 is closed and the washing 
can either be continued or else a fixing cycle can be commenced in a 
similar way as the developing cycle. After the fixing cycle is completed a 
further washing cycle is carried out in the lower chamber in a similar 
fashion to the washing cycle in the upper chamber. On completion of the 
washing cycle in the lower chamber, all liquid is drained out of the lower 
chamber, valve 22 is shut, valve 17 remains open and valve 23 is opened to 
admit warm drying air into the lower chamber. This dries the film and on 
completion seal 7 is opened to allow the film to drop out of the lower 
chamber. 
In order to increase the speed of operation it may be necessary to increase 
the number of chambers and include a further drying chamber below and in 
line with the fixing chamber 2. Further chambers can also be provided for 
developing colour film. 
In FIGS. 2 to 4 can be seen a second developer 30, in which is provided a 
first and upper chamber C1 and a second and lower chamber C2. In an entry 
E to the first chamber C1 is a rotatable gate G1 and between an exit to 
chamber C1 and an entry to chamber C2 is a second rotatable gate G2. A 
third rotatable gate G3 is provided in an exit X to the second chamber C2. 
Gates G1 and G2 are coupled for rotation by means of a toothed driving 
belt 31, and gate G2 is driven by a synchronous motor 32. Gate G3 is 
driven by a second synchronous motor 33, though it would be possible to 
drive gate G3 from a single motor driving all three gates. 
Between gate G1 and chamber C1 are feed rollers 34 and 35, roller 34 being 
urged by means of a spring 36 onto roller 35 and roller 35 being driven 
through a worm wheel 37 by means of a motor 38. 
Motor 38 also drives through a crank or eccentric 39 an agitator plate 40 
which is within chamber C1. 
A fan and fan motor is provided within casing 42 secured to the frame of 
the developer 30 which is arranged to feed drying air via a pipe 43 into 
the lower chamber C2. 
The gate G1 is mounted for rotation together with a rotary valve V1. The 
valve V1 rotates within a valve body B1 which are three inlets, namely a 
developer inlet D, a fixer inlet F and a water inlet W1. Water inlet W1 
further communicates with a groove Z in the valve body B1. The valve V1 is 
provided with a port P extending radially from a central duct Y to the 
periphery of the valve V1. The central duct Y is in communication with a 
diametral slot S1 in gate G1. The diametral slot S1 communicates between 
entry E and chamber C1 via a semi-circular groove R in an alignment 
position. The operation of gate G1 and valve V1 will be further described 
with reference to FIG. 6A to G. 
Gate G2 is provided with a chordial gating slot S2 which opens and closes 
communication between chambers C1 and C2, and a porting slot S3 which 
opens and shuts a drain DR1. The operation of gate G2 will be further 
described with reference to FIG. 6A to G. 
Gate G3 is attached to a rotary valve V2 which rotates within a valve body 
B2. The gate G3 has a chordial slot S4 which opens chamber C2 to exit X. 
Valve V2 has an arcuate porting groove M which provides, when aligned, 
communication between a water inlet W2 in valve body B2 and a water outlet 
W3, also in the valve body B2. The outlet W3 is in communication with a 
water inlet W4 in chamber C2 by means of a pipe 44. Also in the valve body 
B2 is a drain outlet DR2 which is permanently open to chamber C2. The 
operation of gate G3 and valve V2 will be described with reference to FIG. 
7A to D. 
Chamber C2 is provided with an air inlet A in communication with pipe 43 
and blows, when required, drying air down ducts 46 and 47 and angled ports 
48 and 49 (see FIG. 4) into chamber C2. Also in communication with ducts 
46 and 47 is water inlet W4. The angling of the ducts assists in flushing 
the film from chamber C2 to exit X and supports the film away from the 
sides of chamber C2. 
Control of the fan motor and agitator motor 38 is achieved by means of cams 
50 and 51 respectively, which are coupled to gates G3 and G1 respectively. 
The operation of the second developer will now be described with reference 
to FIGS. 6A to G and 7A to D. In FIG. 6A gates G1 and G2, together with 
valve V1, which is coupled to gate G1, are shown in a stand-by position. 
To insert a film, preferably a microfiche, but which can be any sheet 
film, such as an X-ray film, the film is presented to entry E, the 
developer is switched on and the gates rotate so that valve V1 aligns its 
port P with developer inlet D. The developer is then injected into chamber 
C1 as shown in FIG. 6B. The gates and valve then continue to rotate 
closing off the developer inlet D until slot S1 in gate G1 aligns between 
the entry E and chamber C1, as shown in FIG. 6C, The film MF is then fed 
through gate G1 by means of rollers 34 and 35 into chamber C1. During this 
period the agitator plate 40 is operated and the gates G1 and G2 and valve 
V1 rotate to the position shown in FIG. 6D. At which point gate G2 opens 
drain DR1 and the developer is drained and recovered for further use. In 
FIG. 6E the next position of rotation is shown in which port P in valve V1 
aligns with the fixer inlet F and a metered quantity of fixer is injected 
into chamber C1. Fixing continues until valve V1 rotates to the position 
shown in FIG. 6F, when port P in valve V1 aligns with water inlet W1. 
Water is then injected into chamber C1 and drained via drain DR1 which is 
opened by gate G2. This provides a first washing operation for the 
microfiche. It may also be possible at this stage to recover some of the 
fixer from drain DR1. The initial washing action continues the length of 
groove Z until slot S2 in gate G2 is aligned between chambers C1 and C2, 
as shown in FIG. 6G. The film MF then drops into chamber C2, partly 
assisted by flushing water from W1. The flushing water from W1 is allowed 
to drain through DR2, as shown in FIG. 7A. 
FIG. 7A to D shows a second part of the developing operation, which is the 
final washing and drying of the film. FIG. 7A shows the film MF having 
just arrived in chamber C2, and FIG. 7B shows the opening of inlet W2 and 
outlet W3, connected by groove M in valve V2. Water passes from outlet W3 
through pipe 44 to water inlet W4 in chamber C2. The final washing stage 
is then carried out until the position shown in FIG. 7C, and the washing 
water finally drains through drain DR2. The fan in casing 42 is then 
switched on by means of cam 50 and air is passed through inlet A into 
chamber C2, and out through drain DR2. The air drying is then completed by 
the stage reached in FIG. 7D, at which point slot S4 in gate G3 aligns 
between chamber C2 and exit X so that the film MF is blown through gate G3 
to the exit X. 
Whilst the developer is very suitable for the developing of microfiche 
laminae, any suitable sheet film, such as X-ray film, may be developed by 
the developer, which is entirely automatic in operation. 
The present developers are particularly suitable for use with high speed 
microfiche cameras where the flow of microfiches to be developed is 
constant and at a fairly high rate. The developer units can be 
incorporated within a microfiche camera. 
The water supply for the washing processes is preferably coupled direct to 
the domestic water supply mains so that any requirement for pumping water 
is obviated. However, if domestic water supplies are not available an 
additional water supply tank can be provided with pressure suitably 
adjusted to a pressure comparable to that of domestic supplies. 
Development of the film may be carried out by means of a liquid born 
developing agent, or a gas born developing agent. 
Furthermore, it is possible to use a gas born fixing agent or a liquid born 
fixing agent. 
The advantages of using gas born developing and fixing agents in the 
developers according to the invention is that the drying by means of a 
drying gas may be carried out in a shorter time than when liquid born 
developing and fixing agents are used.