High-speed printer having improved ribbon driving,reversing and tensioning mechanism

Claim 2

A compact, reversible ribbon spool drive mechanism adapted for use with a high-speed impact printer, comprising: first and second continuously driven input drive gear trains, each train being mounted for independent oscillatory movement about the axis of one of said gears thereof, while remaining in continuous gear-coupled relationship with the other drive gear train; first and second selectively driven gear trains, each including a different gear-associated spindle for supporting and selectively rotatably driving a ribbon spool in a direction opposite to that of the other spindle; operable reversing means adapted to sense an obstruction carried on a moving ribbon and, in response to each sensed obstruction, rotating said first and second oscillatory mounted drive gear trains in predetermined arcuate directions to couple the previously uncoupled one of said first and second input drive gear trains to a respectively associated one of said first and second driven gear trains, so as to provide positive driving torque alternately, and in opposite angular directions, to said ribbon spool driving spindles thereof, said reversing means including an oscillatory reversing rack mounted for rotation, sAid reversing rack being alternately rotated in opposite directions into coupling engagement with said first and second continuously driven input drive gear trains respectively, each such coupled drive gear train thereafter moving along said rack in a direction so as to become disengaged from the associated one of said first and second driven gear trains; and biasing means for alternately rotating said reversing rack in opposite directions.

Claim 3

A ribbon spool drive mechanism in accordance with claim 1 wherein said biasing means includes: an over-centering lever, mounted on a shaft in common with said reversing rack, and an over-centering spring connected at one end to said over-centering lever and at the other end to said reversing rack for establishing oppositely directed, and reversibly controlled, rotational forces thereagainst, said forces urging said reversing rack alternately into engagement with the respectively associated first and second drive gear trains, said engagement being in response to controlled pivotal movement of said over-centering lever alternately in opposite directions by an amount, relative to said reversing rack, so as to cause said over-centering spring to pass through a balanced center line condition, whereupon it abruptly reverses the opposed rotational spring-biased forces previously applied to said over-centering lever and reversing rack, and biasing means for alternately pivoting said over-centering lever in opposite directions.

Claim 4

A ribbon spool drive mechanism in accordance with claim 1 wherein said reversing rack includes first and second mutually disposed teeth-forming rack sections formed therein, and wherein said first and second drive gear trains are respectively rotatably supported on first and second rotatably mounted oscillatory gear support plates positioned in a common plane and having contoured adjacent mating edges that allow selective overlapping thereof, one with the other, wherein each of said first and second drive gear trains include: a separate pair of continuously coupled planetary gears rotatably mounted on each of said gear support plates, each pair of said planetary gears being positioned so as to move in an arc when brought into engagement with a particular one of said first and second rack sections respectively associated therewith, and to thereby rotate said associated support plate in a direction so as to reverse the overlapping relationship between said gear support plates and cause a change in the coupling of said first and second planetary gears with the respectively associated first and second driven gear trains; and biasing means for continuously urging said first and second gear support plates against each other along the contoured mating and selectively overlapped edges thereof, and for maintaining each alternately coupled pair of planetary gears in engagement with the particular one of said first and second driven gear trains associated therewith until the next succeeding ribbon obstruction is sensed.

Claim 5

A ribbon spool drive mechanism in accordance with claim 2 wherein said reversing means further includes: first and second rotatable stop means, and first and second pivotal sensing arms operably coupled respectively to said first and second rotatable stop means, said stop means being positioned relative to said reversing rack so as to selectively and respectively prevent angular rotation of said reversing rack in opposite angular directions, each of said sensing arms having a ribbon guide slot formed therein and being operable, in response to an obstruction sensed on a ribbon while the latter is drawn through said guide slot in a given direction, to angularly displace both the sensing arm and the one of said first and second rotatable stop means associated therewith, the rotation of said stop means in a given direction being sufficient to allow the reversing rack to be rotated, at least in part by the force exerted thereagainst by said over-centering spring, in a direcTion and to a position whereby the rack section associated with the one of said first and second drive gear trains then providing torque to its associated driven gear train disengages the former from the latter train, while simultaneously allowing the previously disengaged one of said first and second drive gear trains to be brought into engagement with its associated driven gear train so as to provide positive driving torque to the ribbon spool driven spindle associated therewith in a direction opposite to that imparted to the previously driven spindle, whereafter said over-centering spring biases said reversing rack out of engagement with the particular drive gear train previously coupled thereto.

Claim 6

A ribbon spool drive mechanism in accordance with claim 3 wherein said operable reversing means further includes: an over-centering lever, rotatably mounted with said reversing rack, an over-centering spring connected at one end to said over-centering lever and at the other end to said reversing rack for establishing oppositely directed, and reversibly controlled, rotational forces thereagainst, said forces urging the rack sections of the latter alternately into engagement with the respectively associated first and second drive gear trains, said engagement being in response to controlled cam-initiated pivotal movement of said over-centering lever alternately in opposite directions by an amount, relative to said reversing rack, so as to cause said over-centering spring to pass through a centerline force-balanced condition whereupon it abruptly reverses the opposed rotational spring-biased forces previously applied to said over-centering lever and reversing rack, said cam-initiated movement of said lever selectively in opposite directions being produced by the contoured edges of said respective gear support plates when the latter are drivingly rotated alternately in opposite directions, and first and second pivotal ribbon obstruction sensing means, each including a ribbon guide slot, for respectively and alternately sensing movement in opposite directions of at least one obstruction secured to a ribbon while said ribbon is drawn through said guide slots, each of said sensing means, in response to a sensed obstruction, releasing said reversing rack for rotational movement in the proper direction to effect a reversal in ribbon travel.

Claim 7

A ribbon spool drive mechanism in accordance with claim 5 wherein said first and second drive gear trains further respectively include: first and second input drive gears, each rotatably mounted on an axis in common with an associated one of said first and second gear support plates, and being spaced apart so as to be in continuous coupling engagement with each other, and each with one of the gears of said first and second pairs of planetary gears respectively associated therewith, and wherein each pair of said planetary gears are alternately maintained in spring-biased coupling engagement with the respectively associated first and second driven gear trains by the forces produced by both said over-centering spring, through said over-centering lever, and by said biasing means in rotatably urging said first and second gear support plates against each other along the contoured mating edges thereof, and wherein said drive mechanism further includes: means for maintaining the ribbon spool driven gear-associated spindle of each of said first and second driven gear trains under continuous frictional drag so as to maintain a ribbon passing from one spool to the other under continuous tension.

Claim 8

In a high-speed impact printer wherein a ribbon is continuously drawn alternately in opposite directions along and between an aligned array of character printing dies and a web to be printed on, the improvement comprising: a ribbon spool drive mechanism, said mechanism including: first and second power driven drive gear trains, each train being mounted for independent oscillatory movement about the axis of one of said gears theReof, while remaining in continuous gear-coupled relationship with the other of said drive gear trains; first and second driven gear trains, each including a gear associated spindle for mounting and rotatably driving a ribbon spool in a direction opposite to that of the other spindle; operable reversing means adapted to sense an obstruction secured to a moving ribbon and, in response to each sensed obstruction, rotating said first and second oscillatory mounted drive gear trains in predetermined directions so as to alternate the coupling between said first and second drive gear trains and said associated first and second driven gear trains so as to provide positive driving torque alternately, and in opposite angular directions, to said respectively associated ribbon spool driving spindles, said reversing means including: a rotatably mounted reversing rack positioned so as to be alternately rotated in opposite angular directions into engagement with the particular one of said first and second drive gear trains then coupled to an associated driven gear train, and to thereby disengage the former from the latter train; operably controlled biasing means for alternately urging said reversing rack in opposite angular directions into engagement with said first and second drive gear trains, and for urging during that period of time the particular one of said drive gear trains not coupled to said reversing rack into engagement with its associated driven gear; and ribbon obstruction sensing and control means, responsive to each obstruction sensed on a moving ribbon while the latter alternately travels in opposite directions, for releasing said reversing rack for rotation in the proper direction, under the control of said biasing means, then actuated, so as to initiate said reversal in ribbon travel.

Claim 9

In a high-speed impact printer wherein a ribbon is continuously drawn alternately in opposite directions along and between an aligned array of character printing dies and a web to be printed on, the improvement comprising: a ribbon spool drive mechanism, said mechanism including: first and second power driven drive gear trains, each train being mounted for independent oscillatory movement about the axis of one of said gears theReof, while remaining in continuous gear-coupled relationship with the other of said drive gear trains; first and second driven gear trains, each including a gear associated spindle for mounting and rotatably driving a ribbon spool in a direction opposite to that of the other spindle; operable reversing means adapted to sense an obstruction secured to a moving ribbon and, in response to each sensed obstruction, rotating said first and second oscillatory mounted drive gear trains in predetermined directions so as to alternate the coupling between said first and second drive gear trains and said associated first and second driven gear trains so as to provide positive driving torque alternately, and in opposite angular directions, to said respectively associated ribbon spool driving spindles, said reversing means including: a rotatably mounted reversing rack positioned so as to be alternately rotated in opposite angular directions into engagement with the particular one of said first and second drive gear trains then coupled to an associated driven gear train, and to thereby disengage the former from the latter train; operably controlled biasing means for alternately urging said reversing rack in opposite angular directions into engagement with said first and second drive gear trains, and for urging during that period of time the particular one of said drive gear trains not coupled to said reversing rack into engagement with its associated driven gear; and ribbon obstruction sensing and control means, responsive to each obstruction sensed on a moving ribbon while the latter alternately travels in opposite directions, for releasing said reversing rack for rotation in the proper direction, under the control of said biasing means, then actuated, so as to initiate said reversal in ribbon travel.

Claim 10

In a high-speed impact printer in accordance with claim 7, said ribbon spool drive mechanism further comprising: a plurality of guide rollers for directing a ribbon along a circuitous path, including one intermediate region of linear travel adjacent an array of character dies, in passing from one spool to the other, and wherein at least one of said guide rollers is a compensating roller comprising: a spool supporting arbor having mutually disposed and inwardly tapered shank portions which merge into a uniform, cylindrical central portion, and an outer sleeve concentrically mounted on and rotatable relative to said arbor, said sleeve having raised end shoulders and an oversized axial bore extending therethrough, said bore being formed with mutually disposed and outwardly extending tapered end portions which merge at their innermost adjacent ends into a uniform, cylindrical central portion, said sleeve being dimensioned so as to be laterally displaceable on said arbor and, thereby, capable of acquiring a slightly canted position relative to the axis of said arbor in response to, and by an amount necessary to compensate for, any transverse ribbon twist forces that tend to displace said sleeve laterally relative to said arbor.

Claim 11

In a high-speed impact printer in accordance with claim 7, said operably controlled biasing means including: a pivotal over-centering lever, and an over-centering spring, said spring being connected at one end to said reversing rack and at the other end to said over-centering lever, alternate pivotal movement of said lever, relative to said reversing rack, in opposite directions, causing said over-centering spring to pass through a balanced center-line condition after which it abruptly reverses the opposed rotational spring-biased forces previously exerted against said lever and reversing rack, each of said spring-biased reversals causing said reversing rack, after having been initially coupled to one of said first and second drive gear trains, to thereafter be rotated in a direction out of engagement therewith, and causing said over-centering lever, to thereafter, at least in part, bias the previously disengaged one of said first and second drive gear trains into coupling engagement with the driven gear train associated therewith so as to provide driving torque to the previously undriven ribbon spool supporting spindle.

Claim 12

In a high-speed impact printer in accordance with claim 9, said ribbon obstruction sensing means further including: first and second rotatable stop means, and first and second pivotal sensing arms operably coupled to said first and second rotatable stop means, said stop means being positioned relative to said reversing rack so as to selectively and respectively prevent angular rotation of said reversing rack in opposite angular directions, each of said sensing arms having a ribbon guide slot formed therein and being operable, in response to an obstruction sensed on a ribbon while the latter is drawn through said guide slot in a given direction, to angularly displace both the sensing arm and the one of said first and second rotatable stop means associated therewith, the rotation of said stop means in a given direction being sufficient to allow the reversing rack to be rotated under spring-bias in a direction and to a position whereby the rack engages the one of said first and second drive gear trains then providing torque to its associated driven gear train so as to disengage the former from the latter train, while simultaneously allowing the previously disengaged one of said first and second drive gear trains to be brought into engagement with its associated driven gear train so as to provide positive driving torque to the ribbon spool driving spindle associated therewith in a direction opposite to that imparted to the previously driven spindle, whereafter said over-centering spring biases said reversing rack out of engagement with the particular drive gear train previously coupled thereto.

Claim 13

In a high-speed impact printer in accordance with claim 9, said ribbon spool drive mechanism further including: first and second rotatably mounted oscillatory gear support plates positioned in a common plane and having contoured adjacent mating edges that allow selective overlapping thereof, one with the other, and wherein each of said first and second drive gear trains includes: a separate pair of continuously coupled planetary gears rotatably mounted on each of said gear support plates, each pair of said planetary gears being positioned so as to move in an arc when brought into engagement with said reversing rack, and to thereby rotate said associated support plate in a direction so as to reverse the overlapping relationship between said gear support plates and cause a change in the coupling of said first and second planetary gears with the respectively associated first and second driven gear trains, and biasing means for continuously urging said first and second gear support plates against each other along the contoured mating and selectively overlapped edges thereof, and for maintaining each alternately coupled pair of planetary gears in engagement with the particular one of said first and second driven gear trains associated therewith until the next succeeding ribbon obstruction is sensed.

Claim 14

In a high-speed impact printer in accordance with claim 11, said alternate pivotal movement of said over-centering lever in opposite directions is produced by a camming region of the contoured edge of each of the gear support plates when drivingly rotated by the particular pair of planetary gears mounted thereon when brought into engagement with said reversing rack, and said spool ribbon drive mechanism further comprising: means for maintaining the ribbon spool driven gear-associated spindle of each of said first and second drive gear trains under continuous spring-biased frictional drag so as to maintain a ribbon passing from one spool to the other under continuous tension.

Claim 15

In a high-speed impact printer in accordance with claim 12, said ribbon obstruction sensing and control means further including: first and second rotatable stop means positioned relative to said reversing rack so as to selectively and respectively prevent rotation of said rack in opposite angular directions, and first and second pivotal sensing arms, each including a ribbon guide slot, operably coupled respectively to said first and second rotatable stop means, each of said sensing arms, upon sensing a ribbon obstruction moving in a given direction, rotating the associated one of said stop means to release said reversing rack for rotation in the proper direction so as to initiate a reversal in ribbon travel.

Claim 16

In a high-speed impact printer in accordance with claim 9, said ribbon spool drive mechanism further comprising: a plurality of guide rollers for imparting a pre-determined twist to a ribbon on either side of one intermediate region of travel thereof in passing from one spool to the other, and wherein at least one of the guide rollers respectively positioned on either side of each ribbon twist is a compensating roller comprising: a spool supporting arbor having mutually disposed and inwardly tapered shank portions which merge into a uniform cylindrical central portion, and an outer sleeve concentrically mounted on and rotatable relative to said arbor, said sleeve having raised end shoulders and an oversized axial bore extending therethrough, said bore being formed with mutually disposed and outwardly extending tapered end portions which merge at their innermost adjacent ends into a uniform, cylindrical central portion, said sleeve being dimensioned so as to be laterally displaceable on said arbor and, thereby, capable of acquiring a slightly canted position relative to the axis of said arbor in response to, and by an amount necessary to compensate for, any transverse ribbon twist forces that tend to displace said sleeve laterally relative to said arbor.

Claim 17

In a high-speed impact printer in accordance with claim 14, said ribbon spool drive mechanism further comprising: four ribbon guide rollers having their respective axes disposed essentially horizontally, and four guide rollers having their respective axes disposed essentially vertically so as to define a circuitous path of travel for the ribbon between two ribbon spools, with the ribbon having a twist, in opposite directions, imparted thereto on either side of said one region wherein the ribbon is oriented in a vertical plane so as to travel along one linear section of said one region parallel to and oriented broadside of an array of character printing dies and a web, and wherein at least one of said guide rollers respectively positioned on either side of each ribbon twist comprises a compensating guide roller.

Claim 18

In a high-speed impact printer wherein a ribbon is continuously drawn alternately in opposite directions along and between an aligned array of character printing dies and a web to be printed on, the improved combination comprising: a ribbon spool drive mechanism including: first and second mating input drive gears rotatably mounted on respective fixed axes shafts; first and second pairs of planetary gears respectively coupled continuously to and mounted both for rotation with and planetary movement about said first and second drive gears, first and second intermediate gears rotatably mounted on respective fixed axes shafts, first and second pinions secured to said first and second intermediate gears, respectively, first and second rotatably mounted ribbon spool driven gears continuously coupled to said first and second pinions, respectively, and each including a spindle associated therewith to support and selectively drive a ribbon spool when mounted thereon, ribbon obstruction sensing means, and operable ribbon reversing means, responsive to a sensed ribbon obstruction, for alternating the coupling between said first and second pairs of planetary gears and said associated first and second intermediate gears so as to provide positive driving torque alternately, and in opposite angular directionS, to said respectively associated spindles.

Claim 19

In a high-speed impact printer wherein a ribbon is continuously drawn alternately in opposite directions along and between an aligned array of character printing dies and a web to be printed on, the improved combination comprising: a ribbon spool drive mechanism including: first and second mating input drive gears rotatably mounted on respective fixed axes shafts; first and second pairs of planetary gears respectively coupled continuously to and mounted both for rotation with and planetary movement about said first and second drive gears, first and second intermediate gears rotatably mounted on respective fixed axes shafts, first and second pinions secured to said first and second intermediate gears, respectively, first and second rotatably mounted ribbon spool driven gears continuously coupled to said first and second pinions, respectively, and each including a spindle associated therewith to support and selectively drive a ribbon spool when mounted thereon, ribbon obstruction sensing means, and operable ribbon reversing means, responsive to a sensed ribbon obstruction, for alternating the coupling between said first and second pairs of planetary gears and said associated first and second intermediate gears so as to provide positive driving torque alternately, and in opposite angular directionS, to said respectively associated spindles.

Claim 20

In a high-speed impact printer in accordance with claim 16, said operable reversing means further comprising: a rotatable reversing rack having mutually disposed first and second teeth-forming rack sections, an over-centering lever rotatably mounted on a shaft in common with said reversing rack, and an over-centering spring connected at one end to said over-centering lever and at the other end to said reversing rack for establishing oppositely directed, and reversibly controlled, rotational forces thereagainst, said forces urging the rack sections of the latter alternately into engagement with a different associated one of said first and second pairs of planetary gears, said engagement being in response to controlled pivotal movement of said over-centering lever alternately in opposite directions by an amount, relative to said reversing rack, so as to cause said over-centering spring to pass through a balanced center-line condition, whereupon it abruptly reverses the opposed rotational spring-biased forces previously applied to said over-centering lever and reversing rack, and biasing means for alternately pivoting said over-centering lever in opposite directions.

Claim 21

In a high-speed impact printer in accordance with claim 17, said ribbon obstruction sensing means including: first and second rotatable stop means, and first and second pivotal sensing arms operably coupled respectively to said first and second rotatable stop means, said stop means being positioned relative to said reversing rack so as to selectively and respectively prevent angular rotation of said reversing rack in opposite angular directions, each of said sensing arms having a ribbon guide slot formed therein and being operable, in response to an obstruction sensed on a ribbon while the latter is drawn through said guide slot in a given direction, to angularly displace both the sensing arm and the one of said first and second rotatable stop means associated therewith, the rotation of said stop means in a given direction being sufficient to allow the reversing rack to be rotated, at least in part by the force exerted thereagainst by said over-centering spring, in a direction and to a position whereby the rack section associated with the one of said first and second pairs of planetary gears then providing torque to its associated intermediate gear disengages the former from the latter, while simultaneously allowing the previously disengaged one of said first and second pairs of planetary gears to be brought into engagement with its associated intermediate gear so as to provide positive driving torque to the ribbon spool driven spindle associated therewith in a direction opposite to that imparted to the previously driven spindle, whereafter said over-centering spring biases said reversing rack out of engagement with the particular pair of planetary gears previously coupled thereto.