# Patent

## Title
Printer having ribbon shift mechanism

## Abstract

By the foregoing, the applicant has provided a significantly improved reversible drive ribbon cartridge wherein an outer belt is eliminated. Distinctively, the drive belt is placed internally and requires no disassembly and reassembly. Operably, it applies a torque to one ribbon spool in a direction which effects a winding on that spool of the ribbon, which in turn applies a tension to the ribbon across its working station. Thereafter, by virtue of a transmission of tension along the belt, the belt thereafter applies a relaxation of tension to the other ribbon spool. By virtue of this distinct sequence of application of force and relaxation of tension to the ribbon, an ideal tension is maintained at the print station between gides 20 and 22. Also, by the elimination of the toothed portion of the drive roller where it effects drive, the effective diameter of the drive roller is reduced, and thereby a significant increase in usage of ribbon is obtained with the same printer driver. Finally, by the provision of ribbon and belt alignment and guide devices, the center lines of the ribbon and belt are maintained aligned in a common plane relation, thus preventing the belt from sliding across the ribbon surface at the points where the belt and ribbon are in contact and also preventing the outer edges of the ribbon from undesirable frictional contact with the internal surfaces of the top and bottom of the case.

## Background
## Claims

1. A ribbon cartridge for a printer having a drive member, and comprising: 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; 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; 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; means; 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 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: 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; 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; 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; means; 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 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.