US2919785A

US2919785A - Typewriter ribbon control

Info

Publication number: US2919785A
Application number: US625165A
Authority: US
Inventors: Douglas A Newman; Vaccaro Angelo
Original assignee: Columbia Ribbon and Carbon Manufacturing Co Inc
Current assignee: Columbia Ribbon and Carbon Manufacturing Co Inc
Priority date: 1956-11-29
Filing date: 1956-11-29
Publication date: 1960-01-05
Anticipated expiration: 1977-01-05

Description

Jan. 5, 1960 1:. A. NEWMAN` E'TALv 2,919,785/

` TYPEWRITER RIBBON CONTROL Filed Nov. 29, 1956 Y l 2 sheets-snee: 1

POWER 47 SU PPLY 55 l' ff IN V EN TOR5 Jan.5,19eo D, A.N'EWMAN mL 2,919,185

TYPEWRITER RIBOBON CONTROL l 2 Sheets-Sheet 2 Filed NOV. 29, 1956 po wee SUPPLY exrmusr PUMP INVENTORS @Ccd/10 United States Patent() 2,919,785 TYPEWRITER RIBBON CONTROL Application November 29, 1956, serial No. 625,165 s claims. (c1. 197-170) This invention relates to guiding and controlling typewriter ribbons and especially to means for minimizing the necessity for mechanically contacting lthe ribbon by members in the vicinity of the printing point of the machine.

In the typewriter art it has been lthe 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 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 changingribbons, the new rib-- bon must be threaded through their parts. This is a time-consuming procedure which necessarily involves soiling of theoperators hands due to the amount of manipulation of the ribbon required. Secondly, as the typewriter is used there is normally a gradualv collection of ink on the guide parts which rubs olf 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 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 thev side of the ribbon away from the paper, or at that side and lateral edges only, and obviating the need for'I guide elements between the ribbon and the writingpaper adjacent 'the printing point.

is printing, and in magnet.

Vice.

Various ways have also been discovered for exerting the said forces against the ribbon. 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 iirmly but slidably thereagainst by atmospheric air pressure. Or, according to another form of the invention, it has been found that the force may be exerted by including magnetic material in the makeup of the ribbon and providing the guide means with or as a permanent or electro- Also, according to anotherform of the invention, it has been determined that the ribbon can be treated to give it an electrostatic charge whereby it will be attracted to a grounded or oppositely charged guide member, and this embodiment of the invention is at present l preferred. Whichever method is used, the force by which the ribbon is held against the guide can well be characterized as an incorporeally 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 performed Von 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 invention avoids the extraneous and undesired markings produced by the ribbon inadvertently engaging the work adjacent the type impressions or by the guides inadvertently transferring ink material to the work.

Additional objects, features and advantages will appear I of the ribbon holding and adjacent parts of a typewriting machine of the type wheel variety, showing a ribbon guiding mechanism according to a form of the invention wherein the holding force is static electricity.

Fig. 2 is a section taken substantiallyron line 2--2 of Fig. 1, drawn to a larger scale.

Fig. 3 is a view like Fig. 1 but showing an arrangement wherein magnetism is the holding force.

Fig. 4 is a view also like Fig. 1 but showing an arrangement wherein air pressure is the holding force.

Fig. 5 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 static electricity as in the form of the invention shown in Figs. 1 and 2.

Fig. 6 is a detail section taken substantially on line 6 6 of Fig. 5.

Fig.` 7 is like Fig. 5 but shows an arrangement wherein magnetism is the holding force as in Fig. 3.

Fig. 8 is also like Fig. 5 but shows an arrangement wherein air pressure is the holding force as in Fig. 4.

Referring to the drawing, and especially to Figs. 1 and 2, the device in which this form of the invention is embodied includes a type wheel typewriter 11 having a type wheel 13. A let-olf 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 impression 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 3 step-by-step fashion across the printing point in a wellknown manner.

Instead of the usual shield found between the ribbon 17 and the paper 19, the device of Figs. l and 2 employs ribbon guides 31 and 33 made of conductive material, 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 respectively, see Fig. 2, to hold the ribbon against edgewise movement and in proper position as it moves across the machine.

Suitably supported on the machine in a position adjacent the guide 31, i.e. the guide which leads up to the printing point, is a static charge generator 39. In the form shown in Figs. l and 2 this is illustrated as a corona discharge device for electrostatically charging the ribbon 17. As shown the device consists of a pair of conductive posts 41, 43 supporting between them a conductive strand 45. One of the posts is connected to a source 47 of high electrical potential. The posts are shown as mounted in an insulating support plate 49 which is carried on the machine in any suitable fashion. Under certain circumstances, especially with wire of moderately rough surface characteristics, the described structure will operate adequately as a means for charging the surface of the non-conductive ribbon 17. However, where the characteristics require it, a conductive shielding channel 51, grounded as by conductor 53, may also be mounted in the position shown on the side of the wire 45 opposite to the ribbon 17 to enhance the effectiveness of the wire 45 in inducing a static charge. The conductive guide 31 is grounded, as by conductor 55, so that its potential remains at a level which will be attractive to the charged ribbon 17 By virtue of the electrostatic charge applied to the ribbon 17 it is attracted to the guide 31 and adheres securely thereto in the guide channel 35 thereof. As the charged ribbon passes along to the printing point it normally retains some of its charge which causes it to cling to a small arc of the type faces, and further to the surface of guide 33 which is likewise grounded, e.g. by a conductor 57. 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 Z7 and 29 or a take-up spool. While various electrical potential settings and various spacings can be used depending upon the requirements of particular situations, it has been found that application to wire 45 of a potential of between 2000 volts and 600() volts, at a spacing of about 1A; inch from the ribbon surface, works very effectively to produce the desired force holding the ribbon 17 to the guide 31.

As can be seen from Fig. l, the changing of the ribbon is easily and speedily carried out. If the ribbon is of the reusable 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 static charge generator 39 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

2,7, 29 for feeding to a disposal point.

While the device of Fig. l 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, in which case a duplicate static charge generator 39 is also mounted adjacent guide 33, as indicated in dotted lines in Fig. 1.

A second form of the invention is illustrated in Fig. 3 wherein most of the parts are designated similarly to those in Fig. l. Here, however, the static charge generator 39 is omitted, and the ribbon 17m is slightly different in that it includes in its makeup a certain proportion of magnetic material, e.g. pulverulent magnetic iron oxide. Also the

guide elements

31m and 33m have magnetic properties and may be electromagnets, or preferably permanent magnets of the iron-aluminum-nickelcobalt alloy type. It is also possible that the type faces on the type wheel 13 may be made of magnetic material and permanently magnetized as well, to secure a slight additional amount of wrap of the ribbon around the type wheel as in the Fig. 1 arrangement. This, however, would be merely an added refinement and is not essential to the effective use of the invention. In the Fig. 3 form the magnetic attraction of the

guides

31m and 33m supplies the force for holding the ribbon 17m in place in the

channels

35 and 37. Otherwise the operation is identical with that of the device of Fig. l.

In Fig. 4 is illustrated another form of the invention in which guide element 31p is apertured to provide

air passages

59, 59a, 59h, 59a` which communicate with the channel 35p. Likewise guide element 33p is similarly apertured as at 61, 61a, 61b and 61C, which passages communicate with the channel 37p. The terminals of the passage networks remote from the channels 35p and 37p are connected to conduits *63 and 65 which are in turn connected to an exhaust pump 67. The pump 67 lowers the air pressure in the guide channels 35p and 37p at the adjacent side of the ribbon so that the latter is rmly held in place in the guide channels 35p and 37p by the atmospheric air pressure against its exposed face. Otherwise the operation is identical with that of the devices o1 Figs. 1 and 3.

In Figs. 5 to 8 the invention is illustrated in the three forms 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. 5 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 take-up spool 127, which, in the case of a reusable 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 101 which raises and lowers automatically with the typewriter operation in a wellknown manner.

The vibrator 101 also forms a guide for the ribbon and according to the present invention includes two

conductive 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. Mounted near each of the

wings

131 and 133 is a static charge generator 39 which may be similar in all respects to the generator 39 shown in Figs. l and 2. The generators 39 are supplied from a power supply 47 and have their conductive shields 51 grounded as indicated at 53. The vibrator 101 is grounded as indicated by reference numeral 155. The generators 39, in this form, are preferably fixed to a' suitably located portion of the typewriter frame and will perform effectively without moving in accordance with the movement of vibrator 101, since it will act on some f portion of the ribbon in all of the"la'tter's positions. Although 'shown in connection with areusable andreversible ribbon, lit will be understood'that the invention can also be applied where a disposable ribbon-is used, in which case one of the generators'39 can be-dispensed with.

Fig. 7 illustrates a typewriter of the front strike variety like that shown in Fig. 5, but in which'

wing portions

131m and 133m of the vibrator 101m are maguetized, preferably being small permanent magnets, and thus hold a ribbon 117m, which includes in its makeup magnetic material such as iron oxide, firmly in the channel 135.

Fig. 8 illustrates the application of the Fig. 4 principle to a typewriter of the sort shown in Fig. 5. Here the vibrator 105p has

wings

131p and 133p 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 131p, 105p, 133p 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,

vthe 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 vtyping is to be done without making physical contact with the side of the ribbon facing the worksheet-that 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 typewritter, 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 work sheet; means providing a conductive 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 including an electrostatically charged wire displaced from the ribbon and running substantially parallel to the ribbon while the ribbon is in said guideproviding means for generating an electrostatic charge on the ribbon approaching the printing point for holding 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.

2. 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 type-bar guide and worksheet; means providing a conductive 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.adjacenttheeribbon lbutyconfined to positions at the surface ofthe ribbon not directed towards the worksheet; means for` oscillating said guide-,providing means'to place theribbonalternatelypin working position and in a non-interfering, work-reading position; and means including an electrostatically charged electrode displaced from the ribbon and running substantially paraliel to the ribbon for inducing an electrostatic charge on the ribbon approaching the printing point for holding 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.

3. In a typewriter, means including a xed 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 conductive guide surface for said ribbon normally spaced from the worksheet location, positioned between the type-bar guide and the worksheet 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; means for oscillating said guide-providing means to place the ribbon alternately in working position and in a noninterfering, work-reading position; and means fixed adjacent the path of the ribbon opposite each of said guide surface parts for generating an electrostatic charge on the ribbon for holding 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 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 conductive 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 hav- 1ng its parts closely adjacent the ribbon but confined to posltions 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 fixed adjacent the path of the ribbon in a location to act on the ribbon when in either position for generating an electrostatic charge on the ribbon for holding 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 conductive 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 opposite each of said guide surface parts for generating an electrostatic charge on the ribbon for holding 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.

(References on following page) References Cited n the file of this patent UNITED STATES PATENTS Osborne Nov. 6, 1883