Winding – tensioning – or guiding – Coil holder or support – Radially expansible or contractile
Reexamination Certificate
1999-09-15
2002-01-15
Mansen, Michael R. (Department: 3653)
Winding, tensioning, or guiding
Coil holder or support
Radially expansible or contractile
C242S533000, C242S578100, C242S597100
Reexamination Certificate
active
06338452
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a centering photographic material spooling device, as well as a photographic material source or collector with such a spooling device and a photographic material developing machine with a spooling device in accordance with the invention and/or the photographic material source and/or collector in accordance with the invention.
2. Background Information
A reel is normally attached to a holding device for the winding or unwinding of photographic material, and the photographic material is fed thereto or removed therefrom along a fixed transport path. In order to guarantee the same position for the reel, a stop is normally provided for the reel so that the photographic material band can be transferred at a given point to the transport path or taken over thereby.
However, it is often required to wind or unwind photographic material webs or bands, for example, films or photographic paper, of different width. For that case, reels of different width are then used, the side wall disks thereof which are used for guiding the band having a correspondingly different spacing. If reels of different width are pushed onto the same seat up to the stop, a displacement of the center of the photographic material band or web results relative to the stop and relative to the whole transport path. This can be undesired under certain circumstances. For example, certain machines for the processing of photographic material require that the photographic material band is always fed centered about a preselected point. This is especially then the case when an optical processing of the photographic material band takes place wherein the band is to be centered around an optical axis to avoid optical distortion errors. A later lateral displacement of the photographic material band for the centering stresses the photographic material band or web because of the forces acting laterally thereon.
Because of the above-mentioned forces, windup systems or unwind systems were developed which can guide a photographic material web to a transport path or a machine independent of the width of the web or band and centered or can take it up in a centered manner from this machine in order to maintain the mechanical stress on the band as small as possible.
A conventional unwind system includes a reel with an inserted paper roller. The side wall disks with circular circumference are supported on axes which extend perpendicular to the direction of rotation of the side walls (see
FIG. 1
a
). The reel is thereby freely displaceable in axial direction so that a fed out photographic material band can be centered by displacement of the reel.
It is thereby a disadvantage that the reel, because of its free movability along the axes, is not fixed in the direction of movement after centering of the reel and can thereby wonder relative to the center, for example, because of an uneven run of the photographic material web or band or uneven diameters of the side wall disks. This again results in lateral forces which actually were to be prevented and which can damage the photographic material band.
Furthermore, it is also often the case that the reels must be centered in the dark, for example, to avoid exposure of a not yet developed photographic material.
However, a centering of a conventional reel is very difficult in the dark. Subsequent to the unwinding process, the remaining windup roller must again be removed from the reel, for which the side wall disk must first be removed.
A conventional unwind device is rotated by a traction force which acts on the photographic material band. Since the traction force varies during the unwinding of the photographic material, these variations are transferred to the momentum mass of the reel. This results in fluctuations during the unwinding of the photographic material because of the inertia of the reel and the wound-on paper mass. This occurs especially when the photographic material web or band is clamped onto a traction web or band for unwinding, which then strongly accelerates the photographic material web or band.
The thereby created initial oscillation processes highly stress the photographic material band and can damage it. Furthermore, the thereby generated speed fluctuations can be transferred in an undesired manner to the further transport of the photographic material band.
A windup system generally used to date uses the same reel as the above-described unwind device. A windup roller is positioned onto the reel around which then a photo material band is wound up for the formation of a roll of photographic material. Contrary to the unwind device, the side wall disks in the windup device are not positioned on freely rotating axes, but on driven shafts. Those transfer through a frictional engagement, especially contact friction, a driving force onto the side wall disks. A rotation of the windup core is thereby achieved through the side wall disks in order to windup the photographic material.
The above-described disadvantage that the reel can freely wander after centering applies also to the windup device, so that even during the winding up, the photographic material can be stressed with undesired lateral forces. Also, as with the unwind device, the winding core must be removed after the completed windup process, whereby the side wall disks must be removed. The reason for this is especially that the side wall disks impede a further processing of the photographic material roll and that normally only the photographic material roll with the internal windup core is transferred to the further processing.
The driving force, which can be transferred, is also limited in the conventional windup device. As already mentioned, the driving force is transferred by way of friction engagement. However, because of the traction force of the paper, an undesired relative movement of the side wall edges relative to the shafts can occur so that a transition occurs from contact friction to slide friction and that the wind-up speed of the photographic material is thereby all of a sudden strongly reduced because of the reduced driving force. The drive shaft therefore slips and the delivered photographic material band is not taken up to the desired extent so that a jam can occur.
Furthermore, the contact friction between the side walls and the shafts is dependent on the weight of the reel and of the wound up photographic material and, thus, changes depending on the windup condition. In order to avoid the risk of a photographic material band jam, the photographic material band can only relatively loosely wound about the winding core for the above-mentioned reasons, since a photographic material band under tension could overcome the contact friction by way of the traction force caused thereby and could cause a jam. However, a loose paper roll has the disadvantage that it can pull apart by itself when not handled with great care, so that its lateral surfaces are not longer aligned. This can also occur during the winding up, so that the lateral edges of the photographic material then grind along the side walls whereby the photographic material is damaged.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a photographic material winding arrangement which stresses the photographic material band as little as possible and is still easily manipulated. Furthermore, a corresponding photographic material source or photographic material collector and a photo developing machine with the same properties is to be provided.
The photographic material winding arrangement in accordance with the invention includes a winding core seat. This is constructed for receiving a winding core. Winding cores are, for example, constructed as rollers and normally include an especially cylindrical outer surface onto which a photographic material band is wound after the winding core is pushed onto the winding core seat. In order to allow a pushing of the winding core onto the winding core seat, the outer surface of the winding core seat is preferably at least in
Burns Doane , Swecker, Mathis LLP
Gretag Imaging AG
Mansen Michael R.
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