US2973082A - Typewriter ribbon control - Google Patents

Description

TYPEWRIIER RIBBON coNrRor.

Douglas A. Newman, Glen Cove, and Angelo Vaccaro, Port Washington, N .Y., assignors to Columbia Ribbon & Carbon Manufacturing Company, Inc., Glen Cove, N .Y., a corporation of New York Original application Nov. 29, 1956, Ser. No. 625,165,

now Patent No. 2,919,785, dated Jan. 5, 1960. Divided and this application Nov. 20, 1959, Ser. No. 854,344

Claims. (Cl. 197170) This invention relates to guiding and controlling typewriter ribbons and especially to means for minimizing the necessity for mechanically contacting the ribbon by members in the vicinity of the printing point of, the machine. This application is a division of application Serial No. 625,165, filed November 29, 1956, now US Patent N0.-2,919,785, issued January 5, 1960.

In the typewriter art it has been the practice for many years to provide guide means having slots through which the inked ribbon passes in the vicinity of the printing point to restrain the ribbon from too closely approaching the paper, so that the ribbon would normally come into contact with the paper only in the area of printing, and the adjacent paper areas would remain clean. In ordinary front strike typewriters these guides are also automatically vibrated in a vertical direction to present the ribbon in printing position while any type bar is raised, and to withdraw the ribbon below the line of writing to allow reading of the work when the type bars retract. In typewriters of the type wheel variety, adjacent printing types are so closely spaced that there is a tendency for the corners or edges of adjacent type faces to print partially while the actually selected letter is printing, and in this situation it is customary to combine with the guide means a shield between the ribbon and the paper having an opening just large enough to permit printing by a single type face only and thus prevent any tendency to print on the part of adjacent type faces of the wheel.

While guides and shields as described above permit suitable writing operation for a time in many cases, they are a source of much annoyance to typewriter operators. In the first place, when changing ribbons, the new ribbon must be threaded through their parts. This is a time-consuming procedure which necessarily involves soiling of the operators hands due to the amount of manipulation of the ribbon required. Secondly, as the typewriter is used there is normally a gradual collection of ink on the guide parts which rubs off from the ribbon constantly traversing the same. These parts are in close enough proximity to the paper that with a little build-up of this ink deposit, it will soon mark the paper at least faintly as it passes, making for unsightly work unless these surfaces are repeatedly cleaned.

It is the object of the present invention, therefore, to provide for successfully controlling the ribbon of a typewriting machine without contacting the front or writing surface, i.e. the surface towards the paper to be written upon, and so that threading of the ribbon will not be required and the presence of guide elements in a position to transfer accumulated ink to the writing paper will be avoided.

The present invention is carried out by applying to the ribbon restraining forces of a type which do not require mechanical contact to be exerted, and holding the ribbon by such forces against suitable guiding surfaces located at the side of the ribbon away from the paper, or at that 2,973,082 a e t Fe 5 5 1.5

side and lateral edges only, and obviating the need for guide elements between the ribbon and the writing paper adjacent the printing point. It has been found that this may be accomplished by perforating a ribbon guide surface and partially exhausting air from the perforations, so that the ribbon will be held firmly but slidably there-- against by atmospheric air pressure; The force by which the ribbon is held against the guide can well be characterized as an incorpore ally transmitted force, and" this expression will be used hereinafter with this significance.

The present invention is particularly advantageous in connection with high grade work, such as can be per formed on so-called Executive machines using onceused carbon coated paper or plastic ribbons,'and particularly in the typing of direct-image master plates for planographic printing purposes, for the present inventipn avoids the extraneous and undesired markings produced by the ribbon inadvertently engaging the work adjacent the type impressions or by the guides inadvertently trans ferring ink material to the work.

Additional objects, features and advantages will appear as the description proceeds.

For the purposes of illustration and explanation, the invention is shown in detail in those forms currently deemed most practical in the accompanying drawings wherein:

Figure 1 is a top plan, partially diagrammatic, view of the ribbon holding and adjacent parts of a typewriting machine of the type wheel variety, showing a ribbon guiding mechanism according to the invention wherein the holding force is air pressure.

Fig. 2 is a top plan, partially diagrammatic, view of a portion of a front strike type-bar type of typewriter, showing a ribbon guiding mechanism in which the holding force is air pressure as in Fig. 1.

Referring to the drawing, and especially to Fig. l, the device in which the invention is embodied includes a type wheel typewriter 11 having a type wheel 13. A letotf spool 15 supplies a ribbon 17 which passes across in front of the type wheel 13 and between it and a paper sheet 19 which is positioned by paper feed rollers 21, 23. The ribbon may be an ink carrying textile fabric or it may be a carbon coated paper or plastic strip. An im pression hammer 25 is activated by the letter key (not shown) and strikes against the paper moving it into contact with the ribbon 17 and the particular type element of type wheel 13 directly opposite to give the desired mark. The ribbon 17 then leads oif to ribbon feed rollers 27, 29 (or in some cases to a take-up spool) which moves the ribbon in a step-bystep fashion across the printing point in a well-known manner.

Instead of the usual shield found between the ribbon 17 and the paper 19, the device of Fig. 1 employs ribbon guides 31 and 33 placed at either side of the type wheel 13, and so arranged that when the ribbon is stretched taut between them it will lie close to or rest lightly against the type wheel surface. The edge surfaces of the guides are preferably formed with shallow channels 35 and 37 re spectively, to hold the ribbon against edgewise movement and in proper position as it moves across the machine.

By virtue of the suction or vacuum applied to the ribbon 17 it is attracted to the guide 31 and clings securely thereto in the guide channel 35 thereof; While the ribbon clings firmly in place, it still is free to slide lengthwise over the smooth, preferably polished, surfaces of the guides 31 and 33 and the type wheel 13 in response to a pull by the feed rollers 27 and 29 or a takeup spool. The degree of suction, vacuum or'atmospher ic air pressure may be varied depending upon the requirements of particular situations.

As can be seen from Fig. 1, the changing of the ribbon is easily and speedily carried out. If the ribbon is of the re-usable type and is to be replaced, the spool on which it is wound is merely lifted off the machine. The

new spool is put in place and the leading end of the ribbon pulled out and dropped in back of the guides 31 and 33 and drawn into the channels 35 and 37 thereof so that a portion of the ribbon spans the space between the guides and touches the periphery of the type wheel 13. The power is then applied to exhaust pump 67 and the ribbon is merely drawn out a little farther until it clings to the surfaces as heretofore described. The leading end is then connected to the opposite spool. If the ribbon is of the once-used kind, after the full spool is in position and the ribbon carried across the guides 35 and 37, it is led between the feed rollers 27, 29 for feeding to a disposal point.

While the device of Fig. 1 is shown especially in a form designed for use with a once-used or disposable carbon ribbon, it will be understood that as pointed out above a reusable and rewindable ribbon with take-up and let-off spools can be similarly accommodated.

Fig. 1 shows an aspect of the invention in which guide element 31 is apertured to provide air passages 59, 59a, 59b, 590 which communicate with the channel 35. Likewise guide element 33 is similarly apertured as at 61, 61a, 61b and 61c, which passages communicate with the channel 37. The terminals of the passage networks remote from the channels 35 and 37 are connected to con- - duits 63 and 65 which are in turn connected to an exhaust pump 67. The pump 67 lowers the air pressure in the guide channels 35 and 37 at the adjacent side of the ribbon causing a vacuum so that the latter is firmly held in place in the guide channels 35 and 37 by the atmospheric air pressure against its exposed face.

In Fig. 2 the invention is illustrated in the form described above, but as applied to a front strike typewriter having a V-guide for leading a type bar to the printing point and a vibrator for carrying the ribbon alternately up to printing position and down to a level where reading of the copy is possible.

In Fig. 2 is seen a typewriter of the front strike variety having a platen 121 carrying the paper 19. The type bars, one of which is illustrated at 113, move up into printing position and are guided into place by a fixed V- guide 169. The ribbon 117 is carried. between let-off spool 115 and the take-up spool 127, which, in the case of a re-usable ribbon, are capable of automatically interchanging their functions in a manner well-known to the art. The ribbon extends across between the V-guide 169 and the paper 19 and is supported adjacent the printing point on a vibrator 105 which raises and lowers automatically with the typewriter operation in a well-known manner.

The vibrator 105 also forms a guide for the ribbon and according to the present invention includes two side wings 131 and 133. Extending across the face of the vibrator 101 including the wings 131 and 133 is a shallow channel 135 into which the ribbon 117 can be readily placed, and from which it can be readily removed. The vibrator 105 has wings 131 and 133 which have internal passages 159 connected by flexible conduits 163 and 165 with an exhaust pump 67. The pump 67 serves to reduce the air pressure in passages 159, so that the ribbon 117 is held firmly in place in the channel 135 of the guide means 131, 105, 133 by the ambient air pressure.

From the foregoing description it can. be seen that the present invention provides a novel holding and guiding means for typewriter ribbons having the property of firmly holding the ribbon in the proper place against inadvertent displacement, but permitting ready advancing of the ribbon during use, and further providing for quick and easy ribbon changing without the threading operations which make soiling of the users hands almost a necessity. Moreover, as heretofore explained, the machine can be designed without ink-catching guide surfaces near the paper tending to cause smudgy results,

thus doing away with the frequent cleanings heretofore necessary if a good quality of work was to be achieved.

Further, it will be understood that, according to the present invention, the ribbon, be it a fabric, paper or plastic film, will be held in position away from the surface of the worksheet on which the typing is to be done without making physical contact with the side of the ribbon facing the worksheetthat is to say, the side of the ribbon which, in the case of a paper ribbon or plastic, carries transferable carbon material.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

We claim:

, 1. In a typewriter, .means defining a printing point at which the type,. ribbon and worksheet are brought into marking engagement; means for supporting a typewriter ribbon and for feeding the same past said printing point between the type and worksheet; means providing a guide surface for said ribbon normally spaced from the worksheet location in the vicinity of said printing point, said guide-providing means having its parts closely adjacent the ribbon but confined to positions at the surface of the ribbon not directed towards the worksheet; and means for causing atmospheric pressure to hold said ribbon in close contact with said guide surface and away frorn said worksheet, except as the ribbon is locally pressed into contact with the worksheet during typing operations.

2. In a typewriter, means defining a printing point at which the type, ribbon and worksheet are brought into marking engagement; means for supporting a typewriter ribbon and for feeding the same past said printing point between the type and worksheet; means providing a guide surface for said ribbon normally spaced from the Worksheet location in the vicinity of said printing point, said guide-providing means having its parts closely adjacent the ribbon but confined to positions at the surface of the ribbon not directed towards the worksheet, said guide surface being perforate; and means connected with the perforations of said guide surface for exhausting air from between the ribbon and the guide surface for causing atmospheric air pressure to hold said ribbon in close contact with said guide surface and away from said worksheet, except as the ribbon is locally pressed into contact with the worksheet during typing operations.

3. In a typewriter, means including a fixed type-bar guide defining a printing point at which the type, ribbon and worksheet are brought into marking engagement; means for supporting a typewriter ribbon and for feeding the same past said printing point between the typebar guide and worksheet; means providing a guide surface for said ribbon normally spaced from the worksheet location and positioned between the type-bar guide and the worksheet, said guide-providing means having its parts closely adjacent the ribbon but confined to positions at the surface of the ribbon not directed towards the worksheet; means for oscillating said guideproviding means to place the ribbon alternately in working position and in a non-interfering, work-reading position; and means for causing atmospheric pressure to hold said ribbon in close contact with said guide surface and away from said worksheet when in either position, except as the ribbon is locally pressed into contact with the worksheet during typing operations.

4. In a typewriter, means including a fixed typebar guide defining a printing point at which the type, ribbon and worksheet are brought into marking engagement; means for supporting a typewriter ribbon and for feeding the same past said printing point between the typebar guide and worksheet; means providing a guide surface for said ribbon normally spaced from the worksheet location and positioned between the type-bar guide and the worksheet, said guide-providing means having its parts closely adjacent the ribbon but confined to positions at the surface of the ribbon not directed towards the worksheet; means for oscillating said guide-providing means to place the ribbon alternately in working position and in a non-interfering, work-reading position; said guide surface being perforate; and means connected with the perforations of said guide surface for exhausting air from between the ribbon and the guide surface in either position thereof for causing atmospheric air pressure to hold said ribbon in close contact with said guide surface and away from said worksheet when in either position, except as the ribbon is locally pressed into contact with the worksheet during typing operations.

5. In a typewriter, means defining a printing point at which the type, ribbon and worksheet are brought into marking engagement; means for supporting a typewriter ribbon and for feeding the same past said printing point between the type and worksheet; means providing a guide surface for said ribbon normally spaced from the worksheet location in the vicinity of said printing point and having two parts extending in opposite directions from said printing point along the ribbon, said guide-providing means having its parts closely adjacent the ribbon but confined to positions at the surface of the ribbon not directed towards the worksheet; and means for causing atmospheric pressure to hold said ribbon in close contact with the guiding surface of each of said parts and away from said worksheet, except as the ribbon is locally pressed into contact with the Worksheet during typing operations.

No references cited.

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