referring now to the drawings , where like elements are designated by like reference numerals , there is shown in fig1 a film support system 10 constructed in accordance with a preferred embodiment of the present invention . a detailed description of the illustrated system 10 is provided below . the present invention should not be limited , however , to the specific features of the illustrated system 10 . the film support system 10 has an ink film 12 , a supply core 14 , a take - up core 16 , and a frame 18 . rotation of the supply core 14 is braked ( that is , resisted but not prevented ) by a brake gear 20 . the take - up core 16 is rotated by a drive gear 22 . in operation , rotation of the drive gear 22 causes the film 12 to be taken up around the take - up core 16 while tension is generated within the film 12 by friction between the brake gear 20 and a cylindrical brake portion 24 of the supply core 14 . the film 12 may be formed of a known flexible sheet - like or ribbon printing medium . the illustrated film 12 contains a flexible backing material and a suitable contrast agent such as colored or black ink . a leading edge 26 of the film 12 may be attached to a main portion 28 of the take - up core 16 . an extended portion 30 of the film 12 is stretched between the cores 14 , 16 . the remainder 32 of the film 12 is wound around the main portion 34 of the supply core 14 . the width of the film 12 is such that it covers all or most of the main portions 28 , 34 of the cores 14 , 16 . in a preferred embodiment , the extended film portion 30 is positioned in a printer of a facsimile machine to be operated upon by a printer head ( not shown ) or the like . as the extended portion 30 is wound around the take - up core 16 , a new extended portion is drawn off from the supply core 14 , such that a fresh film portion is periodically or continuously moved into position adjacent the printer head as desired . the illustrated supply core 14 is a single piece of integrally molded plastic . the core 14 has first and second ends 36 , 38 in addition to the brake and main portions 24 , 34 . the four supply core portions 24 , 34 , 36 , 38 have cylindrical exterior surfaces that are concentric with each other . the main portion 34 is located between and is contiguous with the brake portion 24 and the second end 38 . the brake portion 24 is located between and is contiguous with the first end 36 and the main portion 34 . when the system 10 is assembled within a printer , the first and second ends 36 , 38 fit into respective semi - cylindrical , upwardly open support sections 40 , 42 ( fig2 and 3 ) in the frame 18 , and the brake portion 24 is in frictional contact with the brake gear 20 . the supply core ends 36 , 38 are settled into and rotatably supported on the support sections 40 , 42 , such the frame 18 aligns the centerline 44 of the core 14 on the desired axis of rotation . the brake portion 24 may slip over the brake gear 20 to prevent the system 10 from becoming jammed or stuck as a result of contaminants in the brake gear 20 , or as a result of a malfunction of the brake gear 20 . in addition , since the brake portion 24 does not have any teeth , it is easy to smoothly locate and remove the system 10 from its printing position . that is , an advantage of the illustrated system 10 is that it is not necessary to mesh any teeth into the teeth of the brake gear 20 . the take - up core 16 is a single piece of molded plastic , with first and second ends 46 , 48 ( fig1 ) and an integrally molded gear 50 . the main portion 28 of the take - up core 16 is located between and is contiguous with the first and second ends 46 , 48 . the second end 48 is located between and is contiguous with the main portion 28 and the molded gear 50 . the ends 46 , 48 and the main portion 28 have cylindrical exterior surfaces that are concentric with each other and with the teeth of the molded gear 50 . when the system 10 is assembled within the printer , the take - up core ends 46 , 48 fit into respective semi - cylindrical , upwardly open support sections 52 , 54 of the frame 18 , and the teeth of the molded gear 50 are meshed with the teeth of the drive gear 22 . the take - up core ends 46 , 48 are settled into and rotatably supported on the support sections 52 , 54 such that the frame 18 maintains the centerline 56 of the take - up core 16 on the desired axis of rotation . as shown in fig2 and 3 , the frame 18 has a movable cover 58 with semi - cylindrical openings 60 , 62 , 64 , 66 for covering the support sections 40 , 42 , 52 , 54 to fully enclose the respective ends 36 , 38 , 46 , 48 of the cores 14 , 16 . the cover 58 has an open position , an intermediate position and a closed position . when the cover 58 is in its open position ( not shown ), the cores 14 , 16 and film 12 can be moved into or removed from the support sections 40 , 42 , 52 , 54 , for example to replace a spent or damaged film 12 . the cover 58 is shown in fig2 and 3 in its intermediate position , moving in the direction of arrow 68 from the open position to the closed position . in the closed position ( not shown ), the lower - most edges of the downwardly open semi - cylindrical cover openings 60 - 66 match the upper - most edges of the support sections 40 , 42 , 52 , 54 to form smooth , encircling , rotation - facilitating axle connections between the core ends 36 , 38 , 46 , 48 and the frame 18 . in this way , the cover 58 contributes to the positional maintenance of the core centerlines 44 , 56 on the desired axes of rotation . in the closed position , lower guide edges 70 , 72 of the cover 58 rest on corresponding guide edges 74 , 76 of the lower portion 78 of the frame 18 . if desired , the frame 18 , including the cover 58 , may be constructed generally like the frame ( or case ) and cover shown in u . s . pat . no . 6 , 543 , 945 . according to a preferred embodiment of the invention , and as discussed in more detail below , the lengths and diameters of the core ends 36 , 38 , 46 , 48 are sized to provide stable positioning and rotatability within the frame 18 while the cover 58 is in its closed position . according to one aspect of the invention , however , the radial dimensions of the core ends 36 , 38 , 46 , 48 are not necessarily the same as and do not necessarily match the radial dimensions of the corresponding frame enclosures 40 , 60 , 42 , 62 , 52 , 64 , 54 , 66 . if desired , the frame 18 , including the cover 58 , may be sized to operatively receive supply and take - up cores that are substantially different than the ones described in the present specification . referring now to fig4 , the diameter 90 of the first end 36 of the supply core 14 may be in the range of from about 0 . 440 inches to about 0 . 500 inches . in the illustrated embodiment , the first end diameter 90 is about 0 . 470 inches . the inner diameter 91 ( fig1 ) of the hollow core 14 is selected to provide sufficient wall strength without using an excessive amount of plastic material . the diameter 92 ( fig4 ) of the brake portion 24 is such that the desired friction is applied to the ends of the teeth of the brake gear 20 during operation . the brake portion diameter 92 is greater than the first end diameter 90 . for example , the brake portion diameter 92 may be in the range of from about 0 . 750 inches to about 0 . 810 inches . in the illustrated system 10 , the brake portion diameter 92 is about 0 . 780 inches . note that the brake portion diameter 92 is preferably selected such that the brake portion 24 is biased in a first direction 93 ( fig1 ) by pressure applied by the brake gear 20 , while the first supply core end 36 is biased in the opposite direction by pressure applied by the encircling frame connection 40 , 60 . the friction generated where the first supply core end 36 rotatably slides within the frame 40 , 60 supplements the friction applied to the supply core 14 by the brake gear 20 , and contributes to the stable tension - generating braking operation of the film system 10 . the diameter 94 of the supply core main portion 34 may be less than the diameter 92 of the brake portion 24 . the main portion diameter 94 is selected to provide the desired room for the wound up film 12 , 32 . in addition , the relative diameters 92 , 94 of the brake portion 24 and the main portion 34 should be arranged to provide the desired tension to the extended film portion 30 during printing . the main portion diameter 94 may be , for example , in the range of from about 0 . 720 inches to about 0 . 780 inches . in the illustrated embodiment , the main portion diameter 94 is about 0 . 750 inches . the diameter 96 of the second end 38 of the supply core 14 may be greater than the first end diameter 90 , to provide for rotation of the supply core 14 in a stable condition within the frame 18 . the difference between the end diameters 90 , 96 may also be used to provide a quality control function , to ensure that inferior film products are not installed in the printer , and / or to ensure that film is easily installed in the printer in the proper orientation . the main portion diameter 94 is greater than the second end diameter 96 so that the main portion 34 does not tend to slip into the frame opening 42 , 62 . the second end diameter 96 may be for example , in the range of from about 0 . 600 inches to about 0 . 660 inches . in the illustrated embodiment , the second end diameter 96 is about 0 . 630 inches . referring now to fig5 , the diameter 98 of the first take - up core end 46 may be essentially the same as the diameter 96 of the second supply core end 38 . in particular , to provide the desired fit , selective assembly and stable rotation in the frame 18 , the diameter 98 of the first take - up core end 46 should be closer to the diameter 96 of the second supply core end 38 than to the diameters 90 , 100 of the other core ends 36 , 48 . in the illustrated embodiment , the diameter 98 of the first take - up core end 46 is in the range of from about 0 . 600 inches to about 0 . 660 inches , more preferably , the diameter 98 is about 0 . 630 inches . the diameter 102 of the main portion 28 of the take - up core 16 may be much greater than the diameter 98 of the contiguous first end 46 , but less than the main portion diameter 94 of the other core 14 . for each core 14 , 16 , the main portion diameters 94 , 102 should be essentially uniform across the entire lengths of the main portions 28 , 34 . further , the diameter 102 of the main take - up portion 28 should be sized relative to the teeth of the molded gear 50 to provide the desired driving force ( torque in the film winding direction ). the take - up core main portion diameter 102 may be , for example , in the range of from about 0 . 675 inches to about 0 . 735 inches . in the illustrated embodiment , the take - up core main portion diameter 102 is about 0 . 705 inches . the diameter 100 of the take - up core second end 48 may be less than the diameter 98 of the take - up core first end 46 , to thereby rotate in a stable condition as desired within the corresponding frame opening 54 , 66 . the take - up core second end diameter 100 may be essentially the same as the supply core first end diameter 90 . in particular , to provide the desired fit , selective assembly and stable rotation in the frame 18 , the take - up core second end diameter 100 should be closer to the supply core first end diameter 90 than to the diameters 96 , 98 of the other core ends 38 , 46 . the take - up core main portion diameter 102 may be greater than the take - up core second end diameter 100 so that the take - up core main portion 28 does not tend to slip into the frame opening 54 , 66 . the take - up core second end diameter 100 may be , for example , in the range of from about 0 . 440 inches to about 0 . 500 inches . in the illustrated embodiment , the take - up core second end diameter 100 is about 0 . 470 inches . in operation , the system 10 may be stored , handled and marketed in a suitable package ( not shown ). during such storage , the cores 14 , 16 are located close to each other . once the system 10 is removed from the package , the cores 14 , 16 are moved away from each other , such that the film 12 unwinds partially from the supply core 14 to form the extended portion 30 between the two cores 14 , 16 . while the printer cover 58 is in its open position , the core ends 36 , 38 , 46 , 48 are placed into and maintained by gravity within the upwardly open support sections 40 , 42 , 52 , 54 . then the cover 58 is rotated ( 68 ) into its closed position , such that the core ends 36 , 38 , 46 , 48 are enclosed within the circular frame openings 40 , 60 , 42 , 62 , 52 , 64 , 54 , 66 . at this stage , the molded gear 50 is meshed with the drive gear 22 , the cylindrical brake portion 24 is in frictional contact with the brake gear 20 , and the extended film portion 30 is located adjacent the printing head . during printing , the film 12 is periodically and / or progressively transferred onto the take - up core 16 until all or most of the film 12 is wound around the take - up core 16 . then the cover 58 is returned to its open position , the cores 14 , 16 and film 12 are removed from the frame 18 , and a new system 10 is positioned within the frame 18 for further printing operations . the above description and drawings are only illustrative of preferred embodiments which can achieve and provide the objects , features and advantages of the present invention . it is not intended that the invention be limited to the embodiments shown and described in detail herein . modifications coming within the spirit and scope of the following claims are to be considered part of the invention .