Claims
- 1. A ribbon cartridge for a printer having a drive member, and comprising:
- a case including broad opposite face sides, front and rear opposite sides, and first and second opposite end sides, said sides defining a cavity, and said case provided at said front side with a pair of spaced guide members;
- first and second spaced drive means within said case, said first drive means including a drive roller adapted to be driven from said printer through one said broad side of said case, said second drive means including a drive roller adapted to be driven from said printer through an opposite said broad side of said case, and said drive rollers positioned generally adjacent said end sides of said case, whereby one of said rollers would be driven at a time;
- a ribbon carried in said cavity;
- ribbon storage and dispensing means disposed in said cavity for storage of said ribbon and for dispensing said ribbon for travel thereof in a prescribed path through an impact region, said ribbon storage and dispensing means comprising first and second spools, said first spool being positioned generally proximate said first drive means, and said second spool being positioned generally proximate said second drive means;
- an idler roller positioned inward of said ribbon storage and dispensing means;
- a belt extending around said drive rollers and said idler roller for rotation of said drive rollers and for movement in a prescribed path over and in contact with said ribbon on said storage and dispensing means and said idler; and
- alignment and guide means carried in said cavity for aligning the center line of said belt and said ribbon in a common plane and for limiting movement of said drive belt and said ribbon in a direction normal to said common plane, said alignment and guide means including a first and second alignment and guide member respectively positioned in spaced relation in said case generally adjacent said first and second opposite end sides and disposed for guiding said ribbon in spaced relation past said drive rollers and between said pair of spaced guide members while simultaneously guiding said belt around said drive rollers and said idler roller and while maintaining the center lines of said ribbon and said belt in alignment.
- 2. A ribbon cartridge for a printer as set forth in claim 1 wherein said alignment and guide means further includes a third alignment and guide member carried by said idler roller in cooperating relation with said first and second guide members to maintain the center line of said belt and said ribbon is aligned relation while maintaining said edges of said ribbon in spaced relation with said broad sides of said case.
- 3. A ribbon cartridge for a printer as set forth in claim 2 wherein said first and second alignment and guide members include a pair of spaced hollow posts having spaced flange surfaces thereon defining ribbon guides and an arcuate portion connecting said posts, said arcuate portion having an elongated slot therein defining a belt guide, the center line of said elongated slot and said ribbon guides being coincident.
- 4. A ribbon cartridge for a printer as set forth in claim 3 wherein said idler roller is mounted on an idler support arm, and said third alignment and guide member includes a body having an opening therein for receiving said idler support arm therein and first and second arms radially extending from said body, each said radially extending arms having spaced flanged surfaces on the distal ends thereof defining a ribbon retainer and guide.
- 5. A ribbon cartridge for a printer as set forth in claim 4 wherein said first radially extending arm includes an elongated slot defining a belt guide having the center line thereof coincident with the center line of said ribbon guide of said first radially extending arm.
- 6. A ribbon cartridge for a printer having a drive member, and comprising:
- a case including broad opposite face sides, front and rear opposite sides, and first and second opposite end sides, said sides defining a cavity, and said case provided at said front side with a pair of spaced guide members;
- first and second spaced drive means within said case, said first drive means including a drive roller adapted to be driven from said printer through one said broad side of said case, said second drive means including a drive roller adapted to be driven from said printer through an opposite said broad side of said case, and said drive rollers positioned generally adjacent said end sides of said case, whereby one of said rollers would be driven at a time;
- a ribbon carried in said cavity;
- ribbon storage and dispensing means disposed in said cavity for storage of said ribbon and for dispensing said ribbon for travel thereof in a prescribed path through an impact region, said ribbon storage and dispensing means comprising first and second spools, said first spool being positioned generally proximate said first drive means, and said second spool being positioned generally proximate said second drive means;
- an idler roller positioned inward of said ribbon storage and dispensing means;
- a belt extending around said drive rollers and said idler roller for rotation of said drive rollers and for movement in a prescribed path over and in contact with said ribbon on said storage and dispensing means and said idler; and
- alignment and guide means carried in said cavity for aligning the center line of said belt and said ribbon in a common plane and for limiting movement of said drive belt and said ribbon in a direction normal to said common plane, said alignment and guide means disposed for guiding said ribbon in spaced relation past said drive rollers while simultaneously guiding said belt around and in contact with said drive rollers and said idler roller, said alignment and guide means comprising a first and second belt alignment and guide member respectively positioned in spaced relation in said case generally adjacent said first and second opposite end sides, and a third belt alignment and guide member positioned in said case adjacent said rear opposite side, said first, second, and third belt alignment and guide members comprised of upper and lower spaced sections molded to said case.
- 7. A ribbon cartridge as set forth in claim 6 wherein said alignment and guide means further includes a first and second ribbon guide means respectively positioned in spaced relation in said case generally adjacent said first and second opposite end sides, said first and second ribbon guide means comprising a raised surface molded on the upper of said broad opposite face sides.
- 8. A ribbon cartridge as set forth in claim 7 wherein said belt guide means is comprised of said upper and lower members provided with an arcuate configuration, said upper member having said raised molded surface extending from a distal end thereof for forming said ribbon alignment and guide means.
- 9. A ribbon cartridge as set forth in claim 7 wherein said alignment and guide means further includes third and fourth ribbon and guide means respectively positioned in spaced relation in said case generally adjacent said front opposite side, said third and fourth alignment and guide means comprising a raised surface molded on the upper of said broad opposite face sides.
Cross-Reference of Related Application
This invention is a continuation-in-part of application Ser. No. 06/855,072, filed Apr. 22, 1986, entitled "Ribbon Cartridge," now U.S. Pat. No. 4,685,817, issued Aug. 11, 1987, which is a continuation-in-part of application Ser. No. 06/725,931, filed Apr. 22, 1985, entitled "Printer Ribbon Cassette," now U.S. Pat. No. 4,629,346, issued Dec. 16, 1986.
This invention relates generally to printing ribbon holders and particularly to belt driven reel-to-reel type ribbon cartridges having guides for guiding the ribbon and belt in a predetermined aligned path.
Printers for printing out the outputs of computers are understandably varied in configuration. Two very popular groups, exemplified by NEC Models 2000/3500/8000 and Diablo HyType II, are of the daisy wheel type, printing a whole character with each stoke of printer operation. These printers employ a ribbon cartridge wherein a ribbon wound on and between two spools is impacted by a character print element of the printer. Cartridge configurations for these printers are illustrated by Meintrup et al. U.S. Pat. No. 4,496,255, Shapiro U.S. Pat. No. 4,533,266 and Kano U.S. Pat. No. 4,544,291. A principal characteristic of such cartridges is that spaced capstan drives, alternately driven through opposite sides of the cartridge by a rotary drive member of a host printer. One of the capstan drives drives a ribbon in one direction, wherein a top region of the ribbon is utilized in printing, and the other capstan drive drives the ribbon in the opposite direction and a bottom region of the ribbon is utilized. Each of the capstan drives consists of a drive roller and a pinch roller, and each capstan drive is associated with one of two spools of the cartridge. A belt is coupled between the driven roller and its associated spool, driving this spool, as a take-up spool, in a direction to receive the ribbon. This belt is positioned on the outside of the cartirdge, connecting between pulleys on shafts of the drive roller and spool. In order to switch directions of drive, the cartridge is turned over and the belt is removed from pulleys on one side of the cartridge and placed around pulleys on the opposite side.
The belt and pulley arrangement discussed is an obvious disadvantage, both from the point of view of inconvenience and the variable tension effected upon the take-up spool as the amount of ribbon on it changes. Perhaps in recognition of the most blatant of these, the inconvenience, Meintrup suggests that an internal belt might be employed and cites a data tape cartridge manufactured by the 3M Company as providing such. This cartridge or cassette is illustrated in von Behren U.S. Pat. No. 3,692,255, and a ribbon cartridge counterpart of it is illustrated in Sasaki U.S. Pat. No. 4,528,572. upon examination of these references, it appears that both employ a single, centrally positioned drive member and thus are employable only with drive units, tapes drives, or printer drives adapted to interface with a central position on a cartridge and not one where separate, spaced capstan drives are employed as required by the printers referred to above. Clearly, neither of these patents provides a teaching as to how one would employ an internal belt in a ribbon cartridge where the drive positions are spaced apart as in the class of cartridge we are concerned with here. In contrast, the inapplicability is manifest and is obvious from the fact that if a belt were stretched between the capstan drives of Meintrup, with an idler symmetrically positioned, e.g., where the drive roller is positioned in the case of Sesaki, the ribbon would be driven by the belt in one direction and the ribbon spool in an opposite direction, an inoperative condition.
In addition to the belt problem, another problem is that of generally providing needed tension on the ribbon of a dual capstan system. Ribbon tension is particularly necessary in the region where the print elements of the printer impact the ribbon to make an imprint on paper. It is important that the ribbon be held taut and constantly so. If there is insufficient tension, the ribbon will tend to drag on the paper and smudge it. If the tension becomes too great, there is a danger of breakage of a ribbon as a printing element impacts on it. Currently available cartridges constructed in accordance with the prior art simply reply upon mechanical drag brought about by the frictional state of the bearing surfaces of a pinch roller, a drive roller, and a spool to provide proper tension. Unfortunately, these frictional factors vary, this variance being paritcularly commercially affected by constantly varying spool sizes as ribbon is fed to and drawn off of the spools. In any event, there is a substantial lack of consistency of ribbon tension.
A still further matter of concern with respect to the merit of ribbon cartridges is that of rate of use of ribbon. Ideally, the ink in the vicinity of an impact by a printing element will be completely utilized but not to the extent that a portion of a character being printed will receive insufficient ink. Pertinently, the rate of ribbon usage is a function of the speed of the rotating drive of the printer and the translation of this speed to a final ribbon drive speed, the latter being a function of the drive mechanism of the cartridge. Since the drive speed is thus fixed by a printer manufacturer, it is up to the ribbon cartridge manufacturer to provide a cartridge which will provide an optimum rate of ribbon advancement for the drive speed at hand. Unfortunately, it appears that because of certain structural limitations imposed by the mechanisms employed in prior art ribbon cartridges, they effect a higher rate of ribbon travel than is actually necessary to provide good print quality. Specifically, it appears that this is the result of employing a direct capstan drive of ribbon, which in turn has necessitated the employment of toothed surfaces to obtain sufficient grip on a ribbon to reliably advance it. This in turn has resulted in an excessive effective diameter of the drive roller, resulting in an excessive effective rate of ribbon advancement.
Further, in addition to the belt problem, the problem of providing needed tension on the ribbon of a dual capstan system, and the problem associated with the rate of use of ribbon, still another problem which merits attention is the need (in internally driven belt systems using spaced spools and capstans with the belt in contact with the ribbon on the spools) for providing alignment and guide means for aligning the center line of the belt and ribbon in coincident relation and for guiding the ribbon in a predetermined path while preventing the edges of the ribbon from undesirable frictional contact with the internal surfaces of the top and bottom of the ribbon casing and also preventing the belt from "riding" across the surface of the ribbon between the edges thereof during the movement of the ribbon between the spools.
In accordance with this invention, alternately, one of two drive rollers, driven by a printer, drives an internally located belt, and this belt engages the ribbon at two locations where it is wound on the spools. It further engages an idler roller, and it engages the other (then undriven) drive roller. The ribbon is not engaged by a drive roller either directly or through the thickness of the belt. The idler roller is positioned to hold the belt against the ribbon where it is wound on ribbon spools. Alignment and guide devices are provided whereby the center line of the belt and ribbon is maintained in alignment in a common plane to prevent "riding" of the belt across the ribbon surface and to maintain the edges of the ribbon in spaced relation with the internal surfaces of the casing to prevent undue frictional engagement therebetween. The devices also maintain the belt and the ribbon in spaced relation as the belt is rotated around the drive rollers.
As a further feature of this invention, the drive roller would be made with a generally even cylindrical contour. By this approach, the effective diameter of the roller is reduced, enabling a lower ribbon drive speed, which results in a significant economy of ribbon usage.
US Referenced Citations (4)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 33974 |
Apr 1981 |
JPX |
| 162682 |
Dec 1981 |
JPX |
Continuation in Parts (2)
|
Number |
Date |
Country |
| Parent |
855072 |
Apr 1986 |
|
| Parent |
725931 |
Apr 1985 |
|
Patent Grant
4820067
