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Ribbon Feed Tensioner

IP.com Disclosure Number: IPCOM000061175D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Feinstein, P: AUTHOR [+2]

Abstract

The ribbon feed tensioner, shown in Fig. 1., is part of the ribbon supply cartridge which is loaded onto the carrier by the printer operator. A ribbon drive mechanism is part of the carrier and provides the proper ribbon feed increments when the machine is operating. On a stop-start printer with bidirectional printing, vibrations and other unwanted motions are introduced into the mechanism during escapement. These unwanted motions can produce a loose or slack ribbon condition in the ribbon cartridge. This can result in various machine failures. The first failure mode can be a clipped character caused by the ribbon dropping below the print point or the printwheel snagging the loose ribbon, moving it upward and above the print point. This is the most common and less critical failure mode.

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Ribbon Feed Tensioner

The ribbon feed tensioner, shown in Fig. 1., is part of the ribbon supply cartridge which is loaded onto the carrier by the printer operator. A ribbon drive mechanism is part of the carrier and provides the proper ribbon feed increments when the machine is operating. On a stop-start printer with bidirectional printing, vibrations and other unwanted motions are introduced into the mechanism during escapement. These unwanted motions can produce a loose or slack ribbon condition in the ribbon cartridge. This can result in various machine failures. The first failure mode can be a clipped character caused by the ribbon dropping below the print point or the printwheel snagging the loose ribbon, moving it upward and above the print point. This is the most common and less critical failure mode. The second failure mode, as a result of slack ribbon, could be poor ribbon spooling. If the proper ribbon tension is not maintained through the drive system, it will result in the ribbon spooling up or down or even up and down. An uneven spooling condition contributes increased frictional forces which can easily require more driving torque than the motor can provide. This failure mode can result in a burned-out motor which would require replacement or a broken ribbon which would result in the remainder of the unused ribbon being discarded. The third failure mode could occur if the printwheel happened to snag the loose ribbon, resulting in the ribbon breaking or possibly to printwheel breaking if the loose ribbon continued to wrap itself around the printwheel. In this condition, the printer could continue to run for a long period of time and do significant damage if it was unattended. Fig. 1 illustrates the ribbon cartridge 4 in a rest position prior to ribbon advancement. The ribbon tension pawl 3 is loaded into the ribbon supply spool 1 by an extension spring 2. This arrangement maintains initial ribbon tension inside the ribbon cartridge 4 and prevents the supply spool 1...