Cassette for rolls of photosensitive material

A cassette for winding and unwinding rolls of photographic paper has a rotatable shaft which traverses the cassette. A spool for supporting a roll of photographic paper is mounted on and circumscribes the shaft. The shaft is supported by a pair of opposite sidewalls of the cassette. Bearing rings are mounted in each of the sidewalls and the shaft carries a pair of bearing disks which respectively mate with the bearing rings. The bearing rings and disks are designed such that they form a braking system for the shaft. An overrunning clutch is arranged between the shaft and each of the bearing disks. The overrunning clutches are oriented so that the shaft rotates freely when photographic paper is being wound onto the spool. During unwinding of photographic paper from the spool, the clutches engage and the braking system for the shaft becomes operative.

BACKGROUND OF THE INVENTION 
The invention relates generally to a cassette or container for 
photosensitive material. 
More particularly, the invention relates to a cassette or container for 
accommodating wound lengths or strips of photosensitive material, 
especially rolls of photographic paper. 
A known cassette for rolls of photosensitive material has a housing which 
may be opened and closed and is impermeable to light when closed. A reel 
for winding and unwinding the rolls of photosensitive material is mounted 
on the housing and the latter has an aperture or slot through which the 
photosensitive material may be withdrawn from the housing and introduced 
therein. The reel carries a coupling member via which the reel may be 
connected to a drive unit for rotating the same. 
Cassettes of the type outlined above are commonly used in photofinishing 
operations. In order to perform such an operation, a roll of unexposed 
photographic paper is loaded into a cassette in a darkroom. This is 
accomplished by opening the housing in order to gain access to the reel 
and then placing the roll on the reel. After the roll is loaded and the 
housing is closed, the cassette is brought into engagement with a copier. 
The photographic paper is unwound from the reel and fed into the copier 
via the slot in the cassette. 
A second cassette is located on the side of the copier remote from the 
loaded cassette. The second cassette is identical to the loaded cassette 
but is empty. The photographic paper is wound into the empty cassette 
after exposure. Once the empty cassette has been loaded, it is removed 
from the copier and taken to a developing machine. The exposed 
photographic paper is then unwound into the developing machine via the 
slot in the cassette. 
In order to wind photosensitive material into a cassette of the type under 
consideration, the reel is connected to a drive unit by means of the 
coupling member provided on the reel. The reel is designed to rotate 
easily during winding. 
The photosensitive material is unwound from the cassette by exerting a pull 
upon the same. It has been found advantageous to exert a braking action 
upon the reel during the unwinding operation. To this end, the cassette is 
provided with a braking mechanism which is designed in such a manner that 
the braking force varies with the weight of the photosensitive material on 
the reel. 
A cassette of the above type is disclosed in the German Offenlegungsschrift 
No. 26 17 233. The cassette includes a braking band or ring which engages 
a braking disk mounted on the reel. The design is such that the braking 
force depends upon the weight of the photosensitive material on the reel. 
This has the result that the tension in the photosensitive material during 
unwinding is essentially independent of the diameter of the roll of 
photosensitive material. 
In order that the braking mechanism may be disengaged for a winding 
operation, the reel is mounted on a pair of support plates which may be 
pivoted up and down. By pivoting the support plates upwards, the braking 
disk is moved out of engagement with the braking band. Upward pivoting of 
the support plates is accomplished by means of guide blocks which are 
secured to the copier on which the cassette is placed. The guide blocks 
are designed in such a manner that they engage the reel and cause the same 
to be pivoted upwards as the cassette is placed on the copier. 
Such a cassette is expensive, extremely complicated and subject to 
malfunctions. Furthermore, the cassette has the disadvantage that any 
copier with which it is used must be provided with devices for changing 
the position of the reel. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the invention to provide a relatively simple container 
for rolls of photosensitive material. 
Another object of the invention is to provide a relatively inexpensive 
container for rolls of photosensitive material. 
An additional object of the invention is to provide a container which is 
capable of accommodating rolls of photosensitive material and is reliable 
in operation. 
A further object of the invention is to provide a container capable of 
accommodating rolls of photosensitive material and having a braking 
mechanism for the rolls which may be disengaged when required by simple 
and inexpensive means. 
A concomitant object of the invention is to improve a container of the type 
outlined above in such a manner that the braking mechanism may be 
disengaged without the use of devices secured to the apparatus on which 
the container is placed during operation. 
The preceding objects, as well as others which will become apparent as the 
description proceeds, are achieved by the invention. 
One aspect of the invention resides in a container for photosensitive 
material, particularly for rolls of photographic paper. The container 
comprises a housing for accommodating a length, e.g. a strip or band, of 
the photosensitive material in wound form. The housing has an aperture for 
introduction of the photosensitive material therein and withdrawal of the 
photosensitive material therefrom. A rotatable element is mounted on the 
housing and serves to wind and unwind the photosensitive material. Braking 
means is provided for braking rotation of the rotatable element. The 
container further includes clutch means arranged to permit braking of the 
rotatable element upon rotation of the latter in a first direction and to 
prevent braking of the rotatable element upon rotation of the same in a 
second direction. 
The braking direction may be that in which the photosensitive material is 
unwound from the housing while the freewheeling direction may be that in 
which the photosensitive material is wound into the housing. 
The clutch means may include an overrunning or freewheeling clutch. The 
clutch may be arranged between the rotatable element and the braking 
means. 
The rotatable element may include a supporting member such as a reel or 
spool which is located internally of the housing and is capable of 
supporting a wound length of the photosensitive material. The braking 
means is then advantageously designed so that the braking force varies 
with the weight of the photosensitive material on the supporting member. 
The rotatable element may be removably mounted on the housing and the 
latter may be designed to be opened and closed in order to permit the 
rotatable element to be mounted on and removed from the housing. The 
housing is advantageously substantially impermeable to light when closed. 
The rotatable element may be provided with a coupling member which enables 
the rotatable element to be connected with a drive unit capable of 
rotating the same. 
In accordance with the invention, control of the braking means is effected 
by making use of the fact that the rotatable element rotates in different 
directions during winding and unwinding of the photosensitive material. 
This makes it unnecessary to provide movable supports for the rotatable 
element as in the German Offenlegungsschrift No. 26 17 233 discussed 
earlier. 
In order to mount the rotatable element on and to remove the same from the 
housing, the latter may be divided into two relatively movable portions. 
Mounting of the rotatable element on and removal of the same from the 
housing may be achieved in a particularly simple manner when the housing 
is divided along a plane which parallels the rotational axis of the 
rotatable element and passes close to or includes such axis. 
The novel features which are considered as characteristic of the invention 
are set forth in particular in the appended claims. The improved container 
itself, however, both as to its construction and its mode of operation, 
together with additional features and advantages thereof, will be best 
understood upon perusal of the following detailed description of certain 
specific embodiments with reference to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, the reference numeral 1 identifies a photographic processing 
apparatus such as, for example, a copier or a developing machine for 
exposed photographic material. A cassette or container 2 which is to be 
connected to the processing apparatus 1 is located alongside the same. 
The cassette 2 is designed to accommodate a roll of photographic paper in 
the form of a strip or a web. To this end, the cassette 2 is provided with 
a rotatable shaft 17 as shown in FIG. 2. The shaft 17 is mounted for 
rotation on an axis 6. Rotation of the shaft 17 in one direction makes it 
possible to unwind a roll of photographic paper which is supported on the 
shaft 17 while rotation of the latter in the opposite direction permits a 
strip or web of photographic paper to be wound into a roll about the shaft 
17. 
Returning to FIG. 1, the cassette 2 is provided with a slot or aperture 7. 
The photographic paper leaves the cassette 2 via the slot 7 during an 
unwinding operation and enters the cassette 2 by means of the slot 7 
during a winding operation. The photographic paper travels in a plane A in 
the region of the slot 7. 
The cassette 2 includes a housing which is divided into a lower portion 3 
and an upper portion 4. The housing 3,4 is divided in the plane A as well 
as in a plane B which extends diagonally of the cassette 2. The plane B is 
parallel to the rotational axis 6 of the shaft 17 and may, but need not, 
include the axis 6. If the plane B does not include the axis 6, it is 
advantageous for the plane B to pass close by the axis 6, that is, the 
distance between the axis 6 and the plane B is preferably small. 
The lower housing portion 3 and upper housing portion 4 are connected to 
one another by a pivot 5 located in the region of one of the lower corners 
of the housing 3,4. The lower housing portion 3 and upper housing portion 
4 may thus be pivoted relative to one another from the closed position 
illustrated in FIG. 1 to an open position in which the interior of the 
housing 3,4 is accessible. The shaft 17 is mounted on the housing 3,4 in 
such a manner that it may be removed from the latter when the housing 3,4 
is in its open position. The housing 3,4 is essentially impermeable to 
light in its closed position. 
Locking elements 8 are provided in the region of the slot 7 to hold the 
lower housing portion 3 and the upper portion 4 together in the closed 
position of the housing 3,4. 
The slot 7 is formed on that side of the cassette 2 which is designed to be 
situated adjacent to the processing apparatus 1 during use. A latch or 
hook 9 is provided on the same side of the cassette 2 and serves to secure 
the cassette 2 to the processing apparatus 1. The latch 9 may also 
function to generate a signal which, for example, indicates that a 
cassette is connected to the processing apparatus 1. 
A manually actuable knob 12 is mounted on the shaft 17 externally of the 
housing 3,4. The knob 12 is rotatable on the axis 6 as indicated by the 
arrow R. 
The bottom of the cassette 2 may be provided with rollers 10 while a handle 
11 for manipulating the cassette 2 may be formed in the region of the 
upper end thereof. 
As shown in FIG. 2, the lower housing portion 3 has a pair of sidewalls 3a 
which are spaced along the direction of the axis 6. Similarly, the upper 
housing portion 4 has a pair of sidewalls 4a which are spaced along the 
direction of the axis 6. A part-circular bearing section 13 is provided in 
each of the walls 4a in the region of the shaft 17. Likewise, a 
part-circular bearing section 14 is mounted on each of the walls 3a in the 
region of the shaft 17. 
The bearing sections 13 have projections 13a whereas the bearing sections 
14 have projections 14a. The projections 13a and 14a extend towards the 
shaft 17 in radial direction of the latter. 
Each of the bearing sections 13 cooperates with the bearing section 14 on 
the same side of the cassette 2 to define an annular bearing member. 
Disks 15a are mounted at the inner sides of the bearing sections 13, that 
is, at the sides of the bearing sections 13 located internally of the 
cassette 2. Disks 15b arranged to mate with the disks 15a in the closed 
position of the cassette 2 are mounted at the inner sides of the bearing 
sections 14. The disks 15a and 15b function as seals in the closed 
position of the cassette 2 to help prevent light from penetrating into the 
interior of the cassette 2. 
The shaft 17 constitutes part of a winding and unwinding unit 16 which may 
be removed from and inserted into the cassette 2 as a whole. The unit 16 
functions to wind photographic paper entering the cassette 2 into a roll 
and to unwind a roll of photographic paper accommodated inside the 
cassette 2 from the latter. 
In addition to the shaft 17, the unit 16 includes a pair of spacer rings 20 
which are mounted on the shaft 17 in the regions of the respective axial 
ends thereof. A cylindrical supporting member 21 is secured to the outer 
circumferences of the spacer rings 20. The outer diameter of the 
supporting member 21 essentially equals the inner diameter of the core of 
a roll of photographic paper to be wound onto or unwound from the unit 16. 
FIG. 2 illustrates a cardboard core 22 which has been slid onto the 
supporting member 21. The cardboard core 22 is confined between a pair of 
flanges 23 which are held against the cardboard core 22 by retaining rings 
24. The retaining rings 24 are secured to the supporting member 21 by 
conventional, non-illustrated connecting elements. 
In accordance with the invention, an overrunning or freewheeling clutch 18 
is mounted at either axial end of the shaft 17. The clutches 18 are 
located outwardly of the respective spacer rings 20 as considered in the 
axial direction of the shaft 17. Each of the clutches 18 is designed with 
an inner race and an outer race. The inner races of the clutches 18 are 
secured to the shaft 17. On the other hand, a pair of annular bearing 
members 19 are secured to the outer races of the respective clutches 18. 
Each of the bearing members 19 is formed with a circumferential groove 19a 
which receives the projections 13a and 14a of the neighboring bearing 
sections 13 and 14. The grooves 19a are coated with layers 19b of a 
material having a high coefficient of friction, at least in those regions 
where the projections 13a and 14a contact the bearing members 19. 
The bearing sections 13 and 14 together with the bearing members 19 define 
a braking mechanism for preventing rotation of the winding and unwinding 
unit 16. 
As clearly seen in FIG. 2, the axial ends of the shaft 17 have different 
diameters. Correspondingly, the two bearing sections 13 have different 
diameters as do the two bearing sections 14 and the two bearing members 
19. The purpose of this design is to ensure that the unit 16 can be 
inserted in the cassette 2 in only one orientation. 
The knob 12 is located at that end of the shaft 17 having the smaller 
diameter. This is the left-hand end of the shaft 17 as seen in FIG. 2. As 
noted previously, the knob 12 is located externally of the cassette 2. The 
end of the shaft 17 having the larger diameter, that is, the right-hand 
end of the shaft 17 as seen in FIG. 2, carries an annular flange 25 which 
is also located externally of the cassette 2. Teeth 26 are formed on the 
circumference of the flange 25 and enable the shaft 17 to be coupled to a 
conventional, non-illustrated drive unit when photographic paper is to be 
wound onto the unit 16. A cavity 27 is provided in the flange 25. The 
cavity 27 makes it possible to readily grasp the flange 25 so that the 
latter may serve as a handle for manipulating the unit 16. 
FIG. 3 is a partly sectional side view of another embodiment of a cassette 
according to the invention. In FIG. 3, the same reference numerals as in 
the preceding FIGS. have been used to identify like components. The 
projections 13a of the bearing sections 13 have circumferentially spaced 
protuberances 13b and 13c which engage the peripheral surfaces of the 
corresponding bearing members 19. Likewise, the projections 14a of the 
bearing sections 14 have circumferentially spaced protuberances 14b and 
14c which bear against the peripheral surfaces of the corresponding 
bearing members 19. 
In the illustrated embodiment, each of the bearing sections 13 has two 
protuberances 13b and 13c while each of the bearing sections 14 has two 
protuberances 14b and 14c. The two protuberances 13b and 13c have 
different circumferential lengths as do the two protuberances 14b and 14c 
The two longer protuberances 13b and 14b have approximately the same 
circumferential length which is about double that of the shorter 
protuberances 13c and 14c. The longer protuberance 13b is 
circumferentially spaced from the associated bearing section 14 while the 
longer protuberance 14b is circumferentially spaced from the associated 
bearing section 13. The two shorter protuberances 13c and 14c are located 
adjacent to one another and cooperate to define a protuberance 13c, 14c 
having a circumferential length approximately equal to that of the longer 
protuberances 13b and 14b. The arrangement is such that the protuberance 
13b, the protuberance 14b and the protuberance 13c, 14c are uniformly 
distributed about the circumference of the bearing member 19. 
The embodiment of FIG. 3 enables a particularly good braking effect to be 
achieved. 
FIG. 4a is an enlarged cross-sectional view of a portion of the braking 
mechanism of FIG. 2. FIG. 4a illustrates that the projections 14a of the 
bearing sections 14, as well as the corresponding grooves 19a of the 
bearing members 19, may have trapezoidal cross sections. With this design, 
the lateral or inclined surfaces of the projections 14a constitute braking 
surfaces as do the lateral or inclined surfaces of the grooves 19a. It 
will be understood that the projections 13a of the bearing sections 13 
have the same shape as the projections 14a. 
FIG. 4b illustrates another embodiment of the braking mechanism. Here, the 
projections 14a and grooves 19a have rectangular cross sections. In this 
case, the braking surfaces are constituted by the circumferentially 
extending end surfaces of the projections 14a and the circumferentially 
extending inner surfaces of the grooves 19a. Again, the configuration of 
the projections 13a is identical to that of the projections 14a. 
In principle, any materials may be used for the bearing sections 13,14 and 
the bearing members 19 as long as sufficient friction is generated at the 
braking surfaces. In the event that insufficient friction is generated by 
direct contact between the bearing members 19 and the cooperating bearing 
sections 13 and 14, either or both of two cooperating braking surfaces may 
be provided with a layer of a material having a high coefficient of 
friction. Layers 19b of such a material are formed on the bearing members 
19 in FIGS. 2,4a and 4b. Appropriate materials for the layers 19b are 
well-known. 
It has been found advantageous to make the bearing members 19 of a 
synthetic resin which is provided with the layers 19b and to make the 
bearing sections 13 and 14 of steel. It will be understood that, 
alternatively, the bearing members 19 may be made of steel while the 
bearing sections 13 and 14 are composed of a synthetic resin which is 
provided with a layer of a material having a high coefficient of friction. 
In operation, the cassette 2 is brought into a darkroom and opened by 
rotating the upper housing section 4 on the pivot 5. The unit 16 is 
removed from the cassette 2 and the retaining ring 24 at the end of the 
shaft 17 having the smaller diameter is disconnected from the supporting 
member 21. This makes it possible to remove the flange 23 located at the 
end of the shaft 17 having the smaller diameter so that a fresh roll of 
photographic paper may be loaded onto the supporting member 21. The flange 
23 and retaining ring 24 are replaced and the unit 16 is subsequently 
lowered onto the bearing sections 14 mounted in the lower housing portion 
3. The different diameters of the two bearing sections 14, as well as the 
different diameters of the two corresponding bearing members 19 on the 
unit 16, insure that the unit 16 is seated on the cassette 2 in the proper 
orientation. The leading end of the roll of photographic paper is placed 
on the bottom surface of the slot 7 in such a manner that it projects to 
the exterior of the cassette 2. The cassette 2 is then closed. 
The cassette 2 is transferred to the processing apparatus 1 which may, for 
example, be a copier, and is connected to the processing apparatus 1 by 
means of the latch 9. The photographic paper is now unwound from the unit 
16 and fed into the processing apparatus 1 via conventional, 
non-illustrated transporting devices such as rollers. 
The clutches 18 are so arranged that, when the unit 16 rotates in the 
unwinding direction for the roll of photographic paper, the clutches 18 
are engaged or locked. As a result, the braking mechanism constituted by 
the bearing sections 13,14 and the bearing members 19 is operative and a 
braking action is exerted on the unit 16. At the beginning of the 
unwinding operation, the braking effect is large since the unit 16 
supports a full roll of photographic paper and the total weight of the 
unit 16 and the roll is high. As the size of the roll decreases, the 
weight decreases also so that the braking effect is continuously 
diminished. By virtue of this arrangement, the tension in the photographic 
paper remains approximately constant throughout the unwinding operation. 
The cassette 2 is connected to the processing apparatus 1 in the region of 
the inlet of the latter during unwinding operations. When the cassette 2 
is to be used for a winding operation, that is, for taking up a strip of 
photographic paper which has been processed in the processing apparatus 1, 
the cassette 2 is attached to the processing apparatus 1 adjacent the 
outlet of the same. 
The cassette 2 is initially empty for a winding operation. The leading end 
of the strip of photographic material passing through the processing 
apparatus 1 is introduced into the slot 7. If the processing apparatus 1 
is a copier, the photographic material leaving the same is exposed. The 
cassette 2 may be provided with devices for guiding the leading end of the 
strip and initiating winding of the strip upon the core 22. However, this 
is not necessary for the invention and the cassette 2 may be opened to 
initiate winding of the strip upon the core 22 by hand. 
The unit 16 is connected with a conventional, non-illustrated drive unit 
which may, for example, consist of an endless toothed belt driven by an 
appropriate motor. The teeth on the belt are brought into mesh with the 
teeth 26 on the flange 25 so that the unit 16 is set into rotation when 
the motor is actuated. The arrangement is such that the unit 16 is rotated 
in a direction opposite to the unwinding direction, that is, in a 
direction which causes the strip of photographic paper to be wound onto 
the unit 16. 
The clutches 18 are oriented in such a manner that they freewheel when the 
unit 16 is rotated in the winding direction. This permits the shaft 17 to 
freely rotate in the clutches 18 while the bearing members 19 remain 
stationary. As a result, the shaft 17 is not subjected to a braking force. 
After the photographic paper processed in the processing apparatus 1 has 
been wound onto the unit 16, the cassette 2 may be disengaged from the 
processing apparatus 1. If the photographic paper was exposed in the 
processing apparatus 1, the cassette 2 may be transferred to a developing 
apparatus. The photographic paper may then be unwound into the developing 
apparatus in the same manner as described earlier with reference to the 
processing apparatus 1. 
By dividing the housing 3,4 of the cassette 2 into the lower housing 
portion 3 and the upper housing portion 4 along the diagonal dividing 
plane B, it becomes possible to place the unit 16 directly onto the lower 
bearing sections 14 in a simple manner. This facilitates mounting of the 
unit 16 on the cassette 2 and eliminates the need for centering the unit 
16 after mounting. 
The knob 12 and the cavity 27 in the flange 25 enable the relatively heavy 
unit 16 to be easily grasped. 
The cassette 2 of the invention has the further advantage that no devices 
need be provided on the processing apparatus 1 for converting the cassette 
2 from a condition in which it is adapted to unwind to a condition in 
which it is adapted to wind. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic and specific aspects of our contribution to 
the art and, therefore, such adaptations should and are intended to be 
comprehended within the meaning and range of equivalence of the appended 
claims.