EP0028539A2 - Print hammer assembly - Google Patents
Print hammer assembly Download PDFInfo
- Publication number
- EP0028539A2 EP0028539A2 EP80303951A EP80303951A EP0028539A2 EP 0028539 A2 EP0028539 A2 EP 0028539A2 EP 80303951 A EP80303951 A EP 80303951A EP 80303951 A EP80303951 A EP 80303951A EP 0028539 A2 EP0028539 A2 EP 0028539A2
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- EP
- European Patent Office
- Prior art keywords
- hammer
- plunger
- assembly
- actuator
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J9/00—Hammer-impression mechanisms
- B41J9/02—Hammers; Arrangements thereof
- B41J9/04—Hammers; Arrangements thereof of single hammers, e.g. travelling along printing line
Definitions
- This invention relates to print hammer assemblies and, more particularly, to a print hammer assembly employing an electromagnetic actuator to drive a hammer element against an adjacent print element, to thereby cause the print element to strike an adjacent platen.
- Such print hammer assemblies are used in impact serial printers of the type including a platen, a plurality of print elements and a marking medium interposed between the print elements and the platen.
- An example of an impact serial printer of this type is disclosed in US Patent No 4 091 911, whereas an example of a print hammer assembly used in such a printer is disclosed in US Patent No 4 037 532.
- the print hammer assembly disclosed in US Patent No 4 037 532 includes a guide housing through which a hammer element is propelled upon being forced in a forward direction by urging of an armature of an electromagnetic actuator following energization thereof.
- the electromagnetic actuator is of a conventional type, wherein a portion of the armature is normally spaced apart from each of a pair of legs of a C-shaped yoke, the connecting portion of which contains an electrically conductive coil wound thereon. A gap is thus defined between the armature and each leg.
- the magnetic field created through each gap forces the armature into contact with the two legs. This movement in turn propels the hammer element through its guide housing in order to impact an adjacent print element, and any interposed recording medium (e.g. paper) and marking material (e.g. inked ribbon) against an adjacent platen.
- any interposed recording medium e.g. paper
- marking material e.g. inked ribbon
- the initial gap distance with the armature in a non-energized position must be precisely adjusted so that the requisite force is achieved upon impact of the armature against the actuator legs, to thereby fire the hammer element with the requisite level of force against the print element.
- Printers where the dwell time of a print element forcing a marking medium against an adjacent platen due to the force of a hammer element against the print element can be increased by increasing the mass of the hammer element. This necessarily increases the quantity of marking material released.
- this arrangement has the disadvantage of increasing the flight time of the hammer element, thereby correspondingly decreasing the maximum printing speed.
- a further disadvantage is that of increasing the kinetic energy of impact, which may result in decreased life of the print elements, or require that the print elements be fabricated of a more durable, and thus more costly, material.
- the platen is inclined in a vertical plane from left to right, the top area of print elements impacting the left portion of the platen might be at least partially deleted, the reverse being true with respect to impacts occurring at the right portion of the platen. This, of course, will lead to an uneven, and perhaps unintelligible print.
- the present invention is intended to provide a print hammer assembly in which those disadvantages of known assemblies may be alleviated.
- the assembly of the invention is characterised by a structure having one of the five features enumerated below.
- a print hammer assembly comprising a support structure having a hammer element supported at a first location thereon and a plunger supported at a second location thereon; an electromagnetic actuator including a pair of magnetizable members displaced apart a predetermined distance to define a space of sufficient dimensions to enable the movement of said plunger therethrough, said actuator including first means capable of being selectively energized for creating a magnetic field in said space to control the movement of said plunger through said space; and second means for'movably mounting said support structure adjacent said electromagnetic actuator such that said plunger is in a position to be forced through said space without touching either magnetizable member upon energization of said first means, whereby said support structure and thus said hammer element will each be moved in a respective predetermined direction and predetermined speed upon energization of said first means.
- the relative distance between the plunger and each of the magnetizable members is not critical, since the total force will be substantially the same regardless of whether or not these two distances differ. More specifically, the driving force is related to the addition of the two gap distances on either side of the plunger and the geometry of the plunger. If the distance between plunger and each of the magnetizable members is different, the driving force will essentially be the same as when the plunger is centered, since the sum of the two distances will always be the same.
- a print hammer assembly comprising a first mass; a second mass including a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled between said first mass and second mass and cooperating with said first mass for increasing the dwell time of said hammer element against said platen or an interposed print element against said platen in response to a single energization of said actuator.
- the mass of the hammer element is not increased to effect an increased dwell time. Rather, a dual mass system is employed, wherein the means for coupling together the two masses includes means cooperating with the first mass for increasing the dwell time. There is thus no decrease in the flight time of the hammer element and increase in kinetic energy of impact.
- a print hammer assembly comprising a support structure defining a first mass and including a plunger at a first location thereon; a second mass including a hammer element; first means for coupling said second mass to said support structure at a second location thereon; and second means for movably mounting said support structure with its plunger adjacent and electromagnetic actuator capable of being selectively energized such that, when said actuator is energized, the resultant magnetic field acting upon said plunger will cause said plunger and thus said support structure and hammer element to each travel along predefined paths at predetermined speeds, said first means including third means cooperating with said first mass for increasing the dwell time of said hammer element against an adjacent platen or an interposed print element against said platen in response to a single energization of said actuator.
- a spring assembly is used to couple the first mass, which includes the support structure, to the second mass, which includes the hammer element.
- a print hammer assembly comprising a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled to said hammer element for causing said hammer element to impact an adjacent platen or an interposed print element against said platen more than once in response to a single energization of said actuator.
- the provision of multi-impact per single energization also contributes to a reduction in noise, since the peak impact forces are less. Further, the two impacts occur relatively rapidly, thereby reducing or avoiding settling of the print element and incumbent in accuracy problems. Still further, there is no transverse movement of the print element between multiple strikes per single energization which could cause "ghosting" and the like, due to the control achieved by impacting more than once per single energization.
- the multi-impact approach of this invention is less susceptable to voids of the marking medium in the printed character, i.e., the second impact fills in at least some of the voids that may have been left in the printed character following the first impact.
- This advantage provides another basis for using lower cost print elements.
- a print hammer assembly comprising a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled to said hammer element for altering the location of maximum impact force of said hammer element against said platen or an interposed print element against said platen, said means for altering including a plurality of adjacent, non-parallel spring members each coupled at one end to said hammer element.
- a pair of normally planar leaf springs are employed.
- the effect of altering the location of maximum impact force following initial impact may be amplified over the effect achieved by using parallel leaf springs.
- This is accomplished due to the trapezoidal configuration of the offset leaf springs as connected to the hammer element at one end and to support structure at the other end.
- the trapezoidal configuration imparts a more pronounced shift in maximum impact force location following initial impact than would a strict parallelogram formed by parallel leaf springs. Consequently, more pronounced misalignments of the platen axis may be compensated for through the use of offset leaf springs in the arrangement above-described.
- a print hammer assembly 10 in accordance with the present invention is shown in Figure 1 mounted to a carriage assembly 12, which may be of the general type disclosed in the aforementioned U.S. Patent No. 4,037,532.
- the carriage assembly 12 is thus adapted to transport not only the hammer assembly 10, but also a rotable print wheel 14 of the "daisy-wheel” type and a ribbon cartridge (not shown) to selected positions along a predefined linear path parallel to the axis of rotation of a cylindrical support platen 16 mounted adjacent the carriage assembly 12.
- the carriage assembly 12 comprises an outer carriage frame 18 and an inner carriage frame 20.
- the inner carriage frame 20 may be pivotably mounted to the outer carriage frame 18 by means of a suitable pivot bolt 22 extending through the side walls of the frames 18 and 20.
- the outer carriage frame 18 is preferably fixed in position in a manner to be described below, and the inner carriage frame 20 is pivotable about bolt 22 relative to frame 18. This pivoting action enables replacement and substitution of print wheels in a manner well known in the art.
- Suitable means (not shown) are provided for locking the inner carriage frame 20 in each of two positions, i.e., a print wheel loaded position (shown in Figure 1) and a print wheel loading position (not shown), wherein the frame 20 would be pivoted clockwise relative to the position shown in Figure 1.
- the outer carriage frame 18 has a pair of aligned openings 24 formed in the respective side walls of frame 18 adjacent the front end of the carriage assembly 12, and a pair of aligned recesses 26 formed in such respective side walls adjacent the rear end of the carriage assembly 12.
- the openings 24 and recesses 26 are each adapted to receive in locked relation a linear bearing assembly (not shown) which may be of the type disclosed in U.S. Patent No. 3,985,404.
- the pair of linear bearing assemblies are adapted to receive a corresponding pair of guide rails (not shown) mounted parallel to the axis of the platen 16 and along which the carriage assembly 12 rides.
- a print wheel motor 28 is mounted by suitable means (not shown) to the inner carriage frame 20.
- the motor 28 controls the speed and direction of rotation of the print wheel 14 in order to bring a desired print or character element 30 thereon to a stationary printing position in alignment with the platen 16 and a hammer element 32 included in the hammer assembly 10.
- the motor 28 has a shaft 34 projecting forwardly of the inner carriage frame 20.
- a hub portion 36 forms part of the shaft 34 and is adapted to be received in the central opening (not shown) of the print wheel 14.
- An exemplary print wheel is generally disclosed in U.S. Patent No. 3,954,163.
- the hammer assembly 10 includes a support structure or frame 38 which defines a first mass and is desirably of generally trapeziodal shape with a pair of inwardly projecting finger portions 40 and 42 coupled at their upper ends by a bridge portion 44.
- a plunger 46 is attached to the outer surface of the bridge 44, or formed as an integral part thereof, which is a plunger 46, which is desirably of a ferromagnetic material, such as soft iron.
- the finger portions 40 and 42 are coupled at their lower ends by generally U-shaped attachment portion 48 having opposing side wall flange portions 50 and 52.
- the flange portions 50 and 52 include respective aligned openings 51 and 54 formed therein.
- the openings 51 and 54 are adapted to accommodate a pivot rod (not shown) that projects through both openings 51 and 54 and a corresponding pair of openings 56 ( Figure 1) in the side walls of the inner carriage frame 20. In this manner, the support frame 38 is pivotably mounted to the inner carriage frame 20.
- the side wall flange portions 52 and 50 of the attachment portion 48 further include respective aligned openings 53 and 55 formed therein. Each such opening is adapted to retain an end of one of a pair of springs 57 (only one shown in Figure 1).
- the other ends of the springs 57 are mounted to the inner frame 20.
- the springs 57 cooperate to bias the support frame 38 in a clockwise direction (as shown in Figure 1) such that the support frame 38 is normally biased against a stop (not shown) also mounted to the inner frame 20.
- the support frame 38 may be pivoted counterclockwise about the pivot rod through openings 56 against the bias of springs 57 upon energization of an electromagnetic actuator 59 forming part of the hammer assembly 10 in a manner to be described below.
- the hammer assembly 10 further includes the hammer element 32, which forms part of a second mass 58 that is coupled to the support frame 38 by at least one, and preferably two, leaf springs 60 and 62.
- the hammer element 32 preferably has a grooved impacting surface 33 that is matable with a corresponding wedge (not shown) formed on the rear surface of each character element 30. In this manner, minor misalignments between the hammer element and the selected character element can be corrected.
- the hammer assembly 10 further includes the electromagnetic actuator or solenoid 59.
- the solenoid 59 has a C-shaped yoke 74 with a pair of depending legs 76 and 78 each containing an electrically conductive coil 80 and 82, respectively, mounted thereon.
- the space 84 between the portion of each leg 76 and 78 projecting downwardly from the respective coil 80 and 82 mounted thereon is of sufficient dimensions to accommodate the plunger 46 therein, as shown in Figure 3. With the plunger 46 positioned within the space 84, gaps 86 and 88 are defined between the sides of the plunger 46 and the adjacent legs 76 and 78, respectively.
- the gaps 86 and 88 need not be identical in dimensions, thereby reducing the necessity of critical adjustments with respect thereto. Additionally, the spacing 85 between the upper surface of the plunger 46 and the lower surfaces of the coils 80 and 82 is not critical. The reasons for these non-critical relationships will be described in more detail below.
- the solenoid 59 is mounted to the inner carriage frame 20 by affixing, through a pair of screws 90, the legs 76 and 78 to a solenoid frame 92, which is itself affixed by means (not shown) to the side walls of the inner carriage frame 20.
- the support frame 38 and solenoid 59 are normally positioned relative to one another such that a front surface 94 of the plunger 46 normally lies just to the rear of the legs 76 and 78 in alignment with the space 84.
- the plunger 46 begins to move through the space 84, thereby causing the support frame 38 to pivot about rod 56 and thus hammer element 32 to move toward the platen 16.
- the hammer element 32 will engage the rear surface of the print element 30 and begin forcing it toward the platen.
- the hammer element 32 will force the print element 30 and an interposed marking medium and record medium, such as an inked ribbon and paper (both not shown), against the platen 16.
- the hammer element 32, and thus print element 30, will each experience a first rebound a predetermined distance from the platen 16.
- the rebound distance of the hammer element 32 is determined by the stiffness and length of the springs 60 and 62, as well as by the ratio of the two masses separated by the springs 60 and 62, and the force of impact, whereas the rebound of the print element 30 is determined by the resiliency of the print wheel spoke bearing the print element 30 and force of theimpact.
- the hammer element 32 will rebound a second time, mainly due to the energy released after impact by the viscoelastic material of platen 16. Additionally, the plunger 46 and thus support frame 38 will continuetheir retract due to the bias of the springs 57 and prior deenergization of the solenoid 59. It must be made clear that the solenoid 59 can be deenergized at any point in time following initial energization, provided the forward driving force imparted to the hammer element 32 is sufficient to achieve the desired multi-impact and consequent desired release of marking material.
- the overall dwell time of the print element 30 against the platen 16 may be increased by continuously energizing the solenoid 59, including for a finite time after the second impact, thereby further increasing the total quantity of marking material (e.g., ink) released.
- the dwell time of the first impact may also be increased by stiffening the springs 60 and 62 or increasing the mass of the hammer element 32 and/or the plunger 46. If desired, the springs 60 and 62 may be stiff enough so that there is no rebound of the hammer element 32 at ail following initial impact. In accordance with the preferred embodiment, however, two distinct impacts are preferred.
- Oscilloscope traces showing the relationships among travel of the hammer element 32, level of current flow through the coils 80 and 82, level of impact force by the hammer element 32, and time, are shown in Figures 9 and 10, for two different profiles of coil current.
- Hammer element travel was measured with an optoelectric device in which hammer element movement is proportional to output voltage, as shown in Figures 9 and 10.
- Current flow was measured with a current probe measuring current through the solenoid coils 80 and 82.
- impact force was measured by piezo-electric force transducer positioned beneath the platen covering.
- Yet another feature of the hammer assembly 10 is occasioned by the parallelogram defined by the pair of parallel springs 60 and 62 connected at one end to the mass 58, which includes tha hammer element 32, and at its other end to the attachment portion 48 of the support frame 38, which defines an additional mass.
- the hammer element 32 could impact the print element 30 against the platen 16 at different impact angles for each of the multiple (e.g., two) impacts as described above. Whether or not this "heel-toe" effect actually takes place depends upon the stiffness of the leaf springs 60 and 62 and the overall realtionship of the springs to the two masses to which they are connected.
- a trapezoidal configuration is thus defined by the springs 60'and 62', mounting blocks 64', 66' and 68', and the attachment portion 48 of the support frame 38 to which the lower ends of the springs 60' and 62' are mounted by suitable interposed mounting blocks (not shown).
- This trapezoidal shape has been found to amplify the counter-clockwise movement, or "heel-toe" effect.
- the heel-toe effect reduces the need for critical adjustments of the platen 16 to insure that its axis of rotaion is completely parallel to the rails (not shown) on which the carriage assembly 12 rides. For example, if the platen axis is skewed relative to the rails in a vertical direction, the top half of characters might not be printed at one end of the paper while the bottom half might be deleted from the other end.
- By striking each print element twice, once low and once high, minor misalignments in a vertical direction will be compensated for in the embodiment of Figures 1-6, and more major misalignments will be compensated for in the embodiment of Figures 7 and 8.
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Abstract
Description
- This invention relates to print hammer assemblies and, more particularly, to a print hammer assembly employing an electromagnetic actuator to drive a hammer element against an adjacent print element, to thereby cause the print element to strike an adjacent platen.
- Such print hammer assemblies are used in impact serial printers of the type including a platen, a plurality of print elements and a marking medium interposed between the print elements and the platen. An example of an impact serial printer of this type is disclosed in US Patent No 4 091 911, whereas an example of a print hammer assembly used in such a printer is disclosed in US Patent No 4 037 532.
- The print hammer assembly disclosed in US Patent No 4 037 532 includes a guide housing through which a hammer element is propelled upon being forced in a forward direction by urging of an armature of an electromagnetic actuator following energization thereof. The electromagnetic actuator is of a conventional type, wherein a portion of the armature is normally spaced apart from each of a pair of legs of a C-shaped yoke, the connecting portion of which contains an electrically conductive coil wound thereon. A gap is thus defined between the armature and each leg. Upon energization of the actuator by passing current of a predetermined magnitude through the coil, the magnetic field created through each gap forces the armature into contact with the two legs. This movement in turn propels the hammer element through its guide housing in order to impact an adjacent print element, and any interposed recording medium (e.g. paper) and marking material (e.g. inked ribbon) against an adjacent platen.
- The type of print hammer assembly as just described has worked quite well and printers in which they have been employed, such as the Diablo HyType II serial printer manufactured by Diablo Systems, Inc. of Hayward, California, have been very sucessful. Certain disadvantages of this type of print hammer assembly have been discerned, however. For example, audible noise attributed to impacts is relatively high. More specifically, not only does the hammer element impact the print element against an adjacent platen, but the armature impacts the two legs of the electromagnetic actuator. Since the armature and legs of the actuator are generally metallic, it will be appreciated that the noise level is significantly increased over that attributable solely to impact of the hammer element against the print element
- Another disadvantage of the type of print hammer assembly described above has to do with the fact that the force of impact (F) of the armature against the actuator legs is inversly proportional to the square of the gap distance (x) between the armature and each leg. Thus, the relationship F=1/x2 is true. This means that the requisite impact force is established over a very short travel and very close to the point of impact of the armature against the actuator legs. As a result of this, it has been found necessary to "fire" the hammer element in a ballistic sense through its guide housing toward the print element. By firing the hammer element, it was found necessary to develop a separate guide housing to control the flight path. The guide housing, however, is subject to wear and dust accumulation, which might effect long-term usage. Further, it will be appreciated that the initial gap distance with the armature in a non-energized position must be precisely adjusted so that the requisite force is achieved upon impact of the armature against the actuator legs, to thereby fire the hammer element with the requisite level of force against the print element.
- Printers are known where the dwell time of a print element forcing a marking medium against an adjacent platen due to the force of a hammer element against the print element can be increased by increasing the mass of the hammer element. This necessarily increases the quantity of marking material released. However, this arrangement has the disadvantage of increasing the flight time of the hammer element, thereby correspondingly decreasing the maximum printing speed. A further disadvantage is that of increasing the kinetic energy of impact, which may result in decreased life of the print elements, or require that the print elements be fabricated of a more durable, and thus more costly, material.
- Another problem with existing serial printers of the type disclosed in US Patent No 4 091 911, which employ a rotatable print wheel mounted to a linearly movable carriage along with a print hammer assembly, the carriage being moved along a path parallel to the longitudinal axis of an adjacent cylindrical platen, has to do with misalignment of the platen. More specifically, the platen must be precisely aligned relative to the carriage such that the carriage path is parallel to the longitudinal axis of the platen. If this relationship is not true, the print elements of the wheel may impact the platen at other 4ocaLions on the periphery, but not in alignment with the center line thereof during linear advancement of the carriage. For example, if the platen is inclined in a vertical plane from left to right, the top area of print elements impacting the left portion of the platen might be at least partially deleted, the reverse being true with respect to impacts occurring at the right portion of the platen. This, of course, will lead to an uneven, and perhaps unintelligible print.
- The present invention is intended to provide a print hammer assembly in which those disadvantages of known assemblies may be alleviated. The assembly of the invention is characterised by a structure having one of the five features enumerated below.
- In accordance with a first feature of the present invention, a print hammer assembly is provided comprising a support structure having a hammer element supported at a first location thereon and a plunger supported at a second location thereon; an electromagnetic actuator including a pair of magnetizable members displaced apart a predetermined distance to define a space of sufficient dimensions to enable the movement of said plunger therethrough, said actuator including first means capable of being selectively energized for creating a magnetic field in said space to control the movement of said plunger through said space; and second means for'movably mounting said support structure adjacent said electromagnetic actuator such that said plunger is in a position to be forced through said space without touching either magnetizable member upon energization of said first means, whereby said support structure and thus said hammer element will each be moved in a respective predetermined direction and predetermined speed upon energization of said first means.
- In view of the above arrangement, it will be appreciated that the only noise generated is that which is attributable to the impact of the print element by the hammer element against an adjacent platen. There is no initial impact of armature or pole piece against other pole pieces, or legs, as in the arrangement disclosed in U.S. Patent No. 4,037,532. This significantly reduces the overall impact noise.
- It will further be appreciated that since the plunger is being magnetically forced through a space between the pair of magnetizable members, the relative distance between the plunger and each of the magnetizable members is not critical, since the total force will be substantially the same regardless of whether or not these two distances differ. More specifically, the driving force is related to the addition of the two gap distances on either side of the plunger and the geometry of the plunger. If the distance between plunger and each of the magnetizable members is different, the driving force will essentially be the same as when the plunger is centered, since the sum of the two distances will always be the same.
- It will also be appreciated that, since the driving force is related to the geometry of the total gap area swept, as opposed to being inversely proportional to the square of an ever decreasing gap size, as in the arrangment disclosed in U.S. Patent No. 4,037,532, much less energy need be expended to achieve the requisite print quality with either system. More specifically, the significant amount of electrical power required to actuate the armature of prior art devices is not required. A substantially lower level of power can be used, thereby conserving energy. Additionally, the geometry of the sweeping gap approach of this invention permits the hammer element to experience maximum acceleration early in the hammer stroke, thus cutting down the overall flight time. This then eliminates the need for a ballistic free flight and its incumbant disadvantages, as described above.
- In accordance with a second feature of the present invention, a print hammer assembly is provided comprising a first mass; a second mass including a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled between said first mass and second mass and cooperating with said first mass for increasing the dwell time of said hammer element against said platen or an interposed print element against said platen in response to a single energization of said actuator.
- It will thus be appreciated that the mass of the hammer element is not increased to effect an increased dwell time. Rather, a dual mass system is employed, wherein the means for coupling together the two masses includes means cooperating with the first mass for increasing the dwell time. There is thus no decrease in the flight time of the hammer element and increase in kinetic energy of impact.
- In accordance with this second feature a print hammer assembly is provided comprising a support structure defining a first mass and including a plunger at a first location thereon; a second mass including a hammer element; first means for coupling said second mass to said support structure at a second location thereon; and second means for movably mounting said support structure with its plunger adjacent and electromagnetic actuator capable of being selectively energized such that, when said actuator is energized, the resultant magnetic field acting upon said plunger will cause said plunger and thus said support structure and hammer element to each travel along predefined paths at predetermined speeds, said first means including third means cooperating with said first mass for increasing the dwell time of said hammer element against an adjacent platen or an interposed print element against said platen in response to a single energization of said actuator.
- Further in accordance with the second feature a spring assembly is used to couple the first mass, which includes the support structure, to the second mass, which includes the hammer element. By then arranging the plunger and hammer element such that the hammer element will strike a print element against a platen while the plunger continues to travel in the same direction, the resiliency of the spring assembly will retain the hammer element against the print element and platen for a longer period of time than had the hammer element been allowed to immediately rebound, as in the case of ballistic hammer assemblies. The increased dwell time also enables the peak impact force to be reduced without loss in print quality, thereby enabling lower cost print element, such as plastic print elements, to be employed.
- In accordance with a third feature of the present invention, a print hammer assembly is provided comprising a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled to said hammer element for causing said hammer element to impact an adjacent platen or an interposed print element against said platen more than once in response to a single energization of said actuator.
- In view of the above, it will be appreciated that the overall amount of marking material released will be increased, since the hammer element will impact the print element and interposed marking medium against the platen more than once for each "hammer energization", i.e., energization of the hammer actuator. Such impacts can be achieved at lower peak force levels, thereby enabling the use of lower cost (e.g., thermo-plastic) print elements and the like, while maintaining high print quality and normal printing speeds.
- While serial impact printers are in existance that cause a hammer element to strike each print element more than once, a separate hammer energization is required for each impact. Since each impact already requires the relatively high peak impact force levels of the prior art, the provision of multiple impacts at that high level of energy will only compound and substantially increase the overall impact energy level and incumbent disadvantages, such as early failure of the print elements or requiring more durable and costly print elements. The present invention avoids this by providing multiple impacts in response to a single actuator energization, where the peak force levels achieved at each such impact can be made substantially less than the conventional levels.
- In addition to the above advantages, the provision of multi-impact per single energization also contributes to a reduction in noise, since the peak impact forces are less. Further, the two impacts occur relatively rapidly, thereby reducing or avoiding settling of the print element and incumbent in accuracy problems. Still further, there is no transverse movement of the print element between multiple strikes per single energization which could cause "ghosting" and the like, due to the control achieved by impacting more than once per single energization.
- As yet another advantage, the multi-impact approach of this invention is less susceptable to voids of the marking medium in the printed character, i.e., the second impact fills in at least some of the voids that may have been left in the printed character following the first impact. This advantage provides another basis for using lower cost print elements.
- In accordance with a fourth impact feature of the present invention, a print hammer assembly is provided comprising a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled to said hammer element for altering the location of maximum impact force of said hammer element following initial impact of said hammer element against said platen or an interposed print element against said platen.
- By altering the location of maximum impact force following initial impact, it will be appreciated that different portions of the print element will be forced against the platen at the maximum impact force, thereby providing a self- correcting feature for most minor misalignments. Altering the location of maximum impact force also serves to improve release of marking material from a marking medium interposed between the print element and platen, as well as to facilitate lift-off of the print element from the marking medium and platen following printing.
- In accordance with a fifth feature of the present invention, a print hammer assembly is provided comprising a hammer element; a hammer actuator capable when energized of directing said hammer element under force toward an adjacent platen; and means coupled to said hammer element for altering the location of maximum impact force of said hammer element against said platen or an interposed print element against said platen, said means for altering including a plurality of adjacent, non-parallel spring members each coupled at one end to said hammer element. Preferable, a pair of normally planar leaf springs are employed.
- By offsetting the pair of leaf springs relative to one another, so that they are non-parallel, the effect of altering the location of maximum impact force following initial impact may be amplified over the effect achieved by using parallel leaf springs. This is accomplished due to the trapezoidal configuration of the offset leaf springs as connected to the hammer element at one end and to support structure at the other end. The trapezoidal configuration imparts a more pronounced shift in maximum impact force location following initial impact than would a strict parallelogram formed by parallel leaf springs. Consequently, more pronounced misalignments of the platen axis may be compensated for through the use of offset leaf springs in the arrangement above-described.
- A print hammer assembly in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
- Figure 1 is a partial side elevation view of an exemplary carriage assembly of a serial printer having mounted thereon a "daisy-wheel" print wheel and a hammer assembly, and being adapted to carry a ribbon cartridge (not shown);
- Figure 2 is a front perspective view of the hammer assembly depicted in Figure 1;
- Figure 3 is a front plan view of a portion of the hammer assembly as depicted in Figure 2;
- Figure 4 is a partial side elevation view of the hammer assembly, print wheel and platen as depicted in Figure 1, showing the hammer assembly upon retraction from a first impact;
- Figure 5 is the same view as Figure 4, but this time showing the hammer assembly upon adancement toward a second impact;
- Figure 6 is the same view as Figures 4 and 5, but this time showing the hammer assembly upon retraction from the second impact;
- Figure 7 is a partial side elevation view of a modified hammer assembly, together with an adjacent print wheel and platen, showing the hammer assembly during a first impact;
- Figure 8 is the same view as Figure 7, but this time showing the hammer assembly during a second impact; and
- Figures 9 and 10 are oscilloscope traces showing the relative relationships among travel of the hammer element, actuator coil current, impact force of the hammer element, and time.
- A
print hammer assembly 10 in accordance with the present invention is shown in Figure 1 mounted to acarriage assembly 12, which may be of the general type disclosed in the aforementioned U.S. Patent No. 4,037,532. Thecarriage assembly 12 is thus adapted to transport not only thehammer assembly 10, but also arotable print wheel 14 of the "daisy-wheel" type and a ribbon cartridge (not shown) to selected positions along a predefined linear path parallel to the axis of rotation of acylindrical support platen 16 mounted adjacent thecarriage assembly 12. - The
carriage assembly 12 comprises anouter carriage frame 18 and aninner carriage frame 20. Theinner carriage frame 20 may be pivotably mounted to theouter carriage frame 18 by means of a suitable pivot bolt 22 extending through the side walls of theframes outer carriage frame 18 is preferably fixed in position in a manner to be described below, and theinner carriage frame 20 is pivotable about bolt 22 relative to frame 18. This pivoting action enables replacement and substitution of print wheels in a manner well known in the art. Suitable means (not shown) are provided for locking theinner carriage frame 20 in each of two positions, i.e., a print wheel loaded position (shown in Figure 1) and a print wheel loading position (not shown), wherein theframe 20 would be pivoted clockwise relative to the position shown in Figure 1. - As shown in Figure 1, the
outer carriage frame 18 has a pair of alignedopenings 24 formed in the respective side walls offrame 18 adjacent the front end of thecarriage assembly 12, and a pair of alignedrecesses 26 formed in such respective side walls adjacent the rear end of thecarriage assembly 12. Theopenings 24 and recesses 26 are each adapted to receive in locked relation a linear bearing assembly (not shown) which may be of the type disclosed in U.S. Patent No. 3,985,404. The pair of linear bearing assemblies are adapted to receive a corresponding pair of guide rails (not shown) mounted parallel to the axis of theplaten 16 and along which thecarriage assembly 12 rides. - A
print wheel motor 28 is mounted by suitable means (not shown) to theinner carriage frame 20. Themotor 28 controls the speed and direction of rotation of theprint wheel 14 in order to bring a desired print orcharacter element 30 thereon to a stationary printing position in alignment with theplaten 16 and ahammer element 32 included in thehammer assembly 10. Themotor 28 has ashaft 34 projecting forwardly of theinner carriage frame 20. Ahub portion 36 forms part of theshaft 34 and is adapted to be received in the central opening (not shown) of theprint wheel 14. An exemplary print wheel is generally disclosed in U.S. Patent No. 3,954,163. - Also mounted to the
inner carriage frame 20 by means to be described below is thehammer assembly 10 of the present invention. As best shown in Figures 2 and 3, thehammer assembly 10 includes a support structure orframe 38 which defines a first mass and is desirably of generally trapeziodal shape with a pair of inwardly projectingfinger portions bridge portion 44. Affixed to the outer surface of thebridge 44, or formed as an integral part thereof, is aplunger 46, which is desirably of a ferromagnetic material, such as soft iron. Thefinger portions U-shaped attachment portion 48 having opposing sidewall flange portions flange portions openings openings openings inner carriage frame 20. In this manner, thesupport frame 38 is pivotably mounted to theinner carriage frame 20. - The side
wall flange portions attachment portion 48 further include respective alignedopenings 53 and 55 formed therein. Each such opening is adapted to retain an end of one of a pair of springs 57 (only one shown in Figure 1). The other ends of thesprings 57 are mounted to theinner frame 20. Thesprings 57 cooperate to bias thesupport frame 38 in a clockwise direction (as shown in Figure 1) such that thesupport frame 38 is normally biased against a stop (not shown) also mounted to theinner frame 20. Thesupport frame 38 may be pivoted counterclockwise about the pivot rod throughopenings 56 against the bias ofsprings 57 upon energization of anelectromagnetic actuator 59 forming part of thehammer assembly 10 in a manner to be described below. - Still referring to Figures 2 and 3, the
hammer assembly 10 further includes thehammer element 32, which forms part of asecond mass 58 that is coupled to thesupport frame 38 by at least one, and preferably two,leaf springs hammer element 32 preferably has a grooved impactingsurface 33 that is matable with a corresponding wedge (not shown) formed on the rear surface of eachcharacter element 30. In this manner, minor misalignments between the hammer element and the selected character element can be corrected. - The
second mass 58 includes three mountingblocks counter-balanced weight 69 affixed to the mountingblock 68. Thehammer element 32 projects forwardly from the center of a side surface of theblock 64. In the embodiment shown in Figures 1-6, theleaf springs blocks hammer element 32 projecting from the mountingblock 64. The upper end of thespring 60 is disposed between the mountingblocks spring 62 is disposed between the mountingblocks springs attachment portion 48 substantially centered between the sidewall flange portions blocks springs attachment portion 48 of thesupport frame 38. - Referring to Figures 1-3, the
hammer assembly 10 further includes the electromagnetic actuator orsolenoid 59. Thesolenoid 59 has a C-shapedyoke 74 with a pair of dependinglegs conductive coil leg respective coil plunger 46 therein, as shown in Figure 3. With theplunger 46 positioned within the space 84,gaps 86 and 88 are defined between the sides of theplunger 46 and theadjacent legs gaps 86 and 88 need not be identical in dimensions, thereby reducing the necessity of critical adjustments with respect thereto. Additionally, the spacing 85 between the upper surface of theplunger 46 and the lower surfaces of thecoils - As shown in figures 1 and 3, the
solenoid 59 is mounted to theinner carriage frame 20 by affixing, through a pair ofscrews 90, thelegs solenoid frame 92, which is itself affixed by means (not shown) to the side walls of theinner carriage frame 20. Thesupport frame 38 andsolenoid 59 are normally positioned relative to one another such that afront surface 94 of theplunger 46 normally lies just to the rear of thelegs solenoid 59 is energized by passing current through thecoils 80 and 82 (clockwise flow throughcoil 80 and counterclockwise flow through coil 82), the resultant magnetic field established through the space 84 and acting upon theplunger 46 will force such plunger against the bias of thesprings 57 through the space 84. This forward movement of theplunger 46 through the space 84 will cause a resultant pivotal movement of thesupport frame 38 about thepivot rod 56 and thus forward arcuate movement of thehammer element 32 toward theadjacent print element 30 andplaten 16. - The operation of the embodiment of the invention as depicted in Figures 1-6 will now be described with respect to Figures 1 and 4-6. Prior to energization of the
solenoid 59, thesupport frame 38 is in the position shown in Figure 1, with theplunger 46 just slightly rearwardof thelegs 76 and 78 of thesolenoid 59, and with thehammer element 32 spaced rearwardly of the alignedprint element 30 of theprint wheel 14. It is important that thesolenoid 59 be energized for a time period sufficient to cause theplunger 46 to overtravel relative to the point along its path of travel at which theprint element 30 and interposed marking medium are initially impacted by thehammer element 32 against theplaten 16. This relationship increases the quantity of marking material released, as will be explained in more detail below. - Following energization of the
solenoid 59, theplunger 46 begins to move through the space 84, thereby causing thesupport frame 38 to pivot aboutrod 56 and thus hammerelement 32 to move toward theplaten 16. During continued movement of thesupport frame 38, thehammer element 32 will engage the rear surface of theprint element 30 and begin forcing it toward the platen. Eventually, thehammer element 32 will force theprint element 30 and an interposed marking medium and record medium, such as an inked ribbon and paper (both not shown), against theplaten 16. When this occurs, and due to the overtravel relationship as identified above, theplunger 46 will have moved only partially through the space 84, as shown in Figure 4. - Upon impact of the
print element 30 against theplaten 16 due to the force of thehammer element 32, thehammer element 32 andprint element 30 will experience a first rebound from the platen. The start of this first rebound condition is also shown in Figure 4. It is to be noted, however, that theplunger 46 will continue to travel in a forward direction due to the dynamics of the dual mass-spring configjration notwithstanding the rebound action of thehammer element 32. It should be apparent that thehammer element 32 is capable of rebounding while the support frame and thus theplunger 46 continue to travel forwardly, due to the action of thesprings - Now then, the
hammer element 32, and thus printelement 30, will each experience a first rebound a predetermined distance from theplaten 16. The rebound distance of thehammer element 32 is determined by the stiffness and length of thesprings springs print element 30 is determined by the resiliency of the print wheel spoke bearing theprint element 30 and force of theimpact. - After the
hammer element 32 has completed its first rebound, the now "cocked" springs 60 and 62 will cause thehammer element 32 to again advance in the direction of theplaten 16, as shown in Figure 5. At the instant of beginning advancement of thehammer element 32 toward theplaten 16, theplunger 46 andsupport frame 38 are essentially at rest, as also shown in Figure 5. Due to the action of thesprings hammer element 32 will again force theprint element 30 and interposed marking medium against theplaten 16. This condition is depicted in Figure 6. During advancement of thehammer element 32 toward the second impact theplunger 46 will begin to retract in a clockwise direction. Following the second impact, thehammer element 32 will rebound a second time, mainly due to the energy released after impact by the viscoelastic material ofplaten 16. Additionally, theplunger 46 and thus supportframe 38 will continuetheir retract due to the bias of thesprings 57 and prior deenergization of thesolenoid 59. It must be made clear that thesolenoid 59 can be deenergized at any point in time following initial energization, provided the forward driving force imparted to thehammer element 32 is sufficient to achieve the desired multi-impact and consequent desired release of marking material. - If desired, the overall dwell time of the
print element 30 against theplaten 16 may be increased by continuously energizing thesolenoid 59, including for a finite time after the second impact, thereby further increasing the total quantity of marking material (e.g., ink) released. The dwell time of the first impact may also be increased by stiffening thesprings hammer element 32 and/or theplunger 46. If desired, thesprings hammer element 32 at ail following initial impact. In accordance with the preferred embodiment, however, two distinct impacts are preferred. It will still be appreciated, however that the overall dwell time is increased by two or more impacts over that which would normally be achieved by a single impact of the prior art hammer assembly disclosed in U.S. Patent No. 4,037,532, since the hammer element of that assembly would immediately rebound following impact. The overall impact time during which marking material is released is obviously greater during a multiple impact condition than a single impact with immediate rebound thereof. - The capability of increasing the overall dwell time, and more importantly increasing the overall quantity of marking material released, has resulted in the capability of reducing the required level of impact force per hit. This has the direct advantage of being able to use somewhat less durable, but considerably lower cost print elements, such as all plastic print wheels, as opposed to metallic or composite metal/plastic wheels, while maintaining high print quality through multi-impacts, and resultant increased overall dwell time and thus increased overall release of marking material. The overall print noise is also reduced without sacrificing print quality.
- Referring again to Figures 2 and 3, it will be appreciated that when current is made to flow clockwise through the
coil 80 and counterclockwise throughcoil 82, a resultant magnetic field will be established through the space 84 to forceplunger 46 in the direction shown by the arrow in Figure 2. The level of force is related to the addition of the sizes ofgaps 86 and 88 and the geometry ofplunger 46. Thus, it makes no difference if one of these two gaps is larger in size than the other, since their sum will always be equal, thereby maintaining a desired level of force through the space 84. The need for critical adjustments of thesupport frame 38 to achieve size identity of thegaps 86 and 88 is thus reduced. Additionally, and as pointed out earlier, the need for critical adjustments of the spacing 85 (Figure 3) is also reduced. - It will also be appreciated that the magnetic force driving the
plunger 46 through the gap 84 is more uniform than that achieved in the prior art assembly of U.S. Patent No. 4,037,532. Specifically, in such prior art assembly, the force was inversly proportional to the square of the distance between a solenoid armature and the rear surface of a hammer actuator element. Further, considerable energy had to be expended to obtain the requisite hammer force level upon impact, due to this relationship. In thehammer assembly 10, no armature is used to impact thehammer element 32 and propel it toward theplaten 16. As a result of the "sweeping gap" approach, thehammer element 32 is able to experience maximum acceleration early in the stroke, thereby more rapidly attaining the desired impact velocity and thus cutting down the flight time. The peak impact force may also be reduced due to the increased overall dwell time occasioned by multiple impacts, and thus consequently increased marking material release, as mentioned above. - Oscilloscope traces showing the relationships among travel of the
hammer element 32, level of current flow through thecoils hammer element 32, and time, are shown in Figures 9 and 10, for two different profiles of coil current. Hammer element travel was measured with an optoelectric device in which hammer element movement is proportional to output voltage, as shown in Figures 9 and 10. Current flow was measured with a current probe measuring current through the solenoid coils 80 and 82. Lastly, impact force was measured by piezo-electric force transducer positioned beneath the platen covering. - Yet another feature of the
hammer assembly 10 is occasioned by the parallelogram defined by the pair ofparallel springs mass 58, which includestha hammer element 32, and at its other end to theattachment portion 48 of thesupport frame 38, which defines an additional mass. By reason of this parallelogram and the action of thesprings hammer element 32 could impact theprint element 30 against theplaten 16 at different impact angles for each of the multiple (e.g., two) impacts as described above. Whether or not this "heel-toe" effect actually takes place depends upon the stiffness of theleaf springs hammer element 32 following the initial impact and just prior to the second impact. This movement may be amplified by offsetting thesprings attachment portion 48 of thesupport frame 38 to which the lower ends of the springs 60' and 62' are mounted by suitable interposed mounting blocks (not shown). This trapezoidal shape has been found to amplify the counter-clockwise movement, or "heel-toe" effect. - By reason of the heel-toe effect achieved by either of the two embodiments, it is possible to mount the
support frame 38 in such a manner that thehammer element 32 will initially impact predominantly the lower portion of theprint element 30, while striking predominantly the upper portion of theprint element 30 during the second impact. It should be appreciated, however, that the importance in this relationship is not necessarily in altering the location of impact by thehammer element 32 against theprint element 30, but rather altering the location of maximum impact force of theprint element 30 against theplaten 16. Thus, altering the location of impact of thehammer element 32 against theprint element 30 is but one way of achieving the desired result. - The heel-toe effect reduces the need for critical adjustments of the
platen 16 to insure that its axis of rotaion is completely parallel to the rails (not shown) on which thecarriage assembly 12 rides. For example, if the platen axis is skewed relative to the rails in a vertical direction, the top half of characters might not be printed at one end of the paper while the bottom half might be deleted from the other end. By striking each print element twice, once low and once high, minor misalignments in a vertical direction will be compensated for in the embodiment of Figures 1-6, and more major misalignments will be compensated for in the embodiment of Figures 7 and 8. - Although an embodiment of the invention has been described using a pair of
leaf springs
Claims (15)
Applications Claiming Priority (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US9165879A | 1979-11-05 | 1979-11-05 | |
US9164579A | 1979-11-05 | 1979-11-05 | |
US91605 | 1979-11-05 | ||
US06/091,605 US4327639A (en) | 1979-11-05 | 1979-11-05 | Print hammer assembly with multi-location impacts |
US06/091,657 US4324497A (en) | 1979-11-05 | 1979-11-05 | Print hammer assembly with amplified multi-location impacts |
US91645 | 1979-11-05 | ||
US9164679A | 1979-12-19 | 1979-12-19 | |
US91646 | 1979-12-19 | ||
US91657 | 1993-07-14 | ||
US91658 | 2002-03-04 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0028539A2 true EP0028539A2 (en) | 1981-05-13 |
EP0028539A3 EP0028539A3 (en) | 1982-05-26 |
EP0028539B1 EP0028539B1 (en) | 1986-04-09 |
Family
ID=27536610
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19800303951 Expired EP0028539B1 (en) | 1979-11-05 | 1980-11-05 | Print hammer assembly |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0028539B1 (en) |
DE (1) | DE3071538D1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0139903A1 (en) * | 1983-09-14 | 1985-05-08 | International Business Machines Corporation | Solenoid actuated pivotal printer hammer mechanism |
US4525086A (en) * | 1983-09-14 | 1985-06-25 | International Business Machines Corporation | Solenoid actuated pivotal printer hammer mechanism |
EP0207781A1 (en) * | 1985-07-02 | 1987-01-07 | Xerox Corporation | Printer impact mechanism |
EP0209291A1 (en) * | 1985-07-02 | 1987-01-21 | Xerox Corporation | Impact printer |
EP0210000A1 (en) * | 1985-07-02 | 1987-01-28 | Xerox Corporation | Impact printer |
EP0226398A2 (en) * | 1985-12-05 | 1987-06-24 | Xerox Corporation | Impact printer with application of oblique print force |
US4737043A (en) * | 1985-07-02 | 1988-04-12 | Xerox Corporation | Impact mechanism for quiet impact printer |
EP0538998A2 (en) * | 1991-10-24 | 1993-04-28 | Smith Corona Corporation | Quiet impact printer mechanism |
EP0540145A2 (en) * | 1991-10-28 | 1993-05-05 | Smith Corona Corporation | Printing mechanism with print hammer having noise dampener |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3472352A (en) * | 1967-06-28 | 1969-10-14 | Burroughs Corp | High speed serial printer |
US3643594A (en) * | 1968-06-11 | 1972-02-22 | Sits Soc It Telecom Siemens | Print hammer for high-speed printer |
-
1980
- 1980-11-05 DE DE8080303951T patent/DE3071538D1/en not_active Expired
- 1980-11-05 EP EP19800303951 patent/EP0028539B1/en not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3472352A (en) * | 1967-06-28 | 1969-10-14 | Burroughs Corp | High speed serial printer |
US3643594A (en) * | 1968-06-11 | 1972-02-22 | Sits Soc It Telecom Siemens | Print hammer for high-speed printer |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0139903A1 (en) * | 1983-09-14 | 1985-05-08 | International Business Machines Corporation | Solenoid actuated pivotal printer hammer mechanism |
US4525086A (en) * | 1983-09-14 | 1985-06-25 | International Business Machines Corporation | Solenoid actuated pivotal printer hammer mechanism |
US4678355A (en) * | 1985-07-02 | 1987-07-07 | Xerox Corporation | Print tip contact sensor for quiet impact printer |
EP0209291A1 (en) * | 1985-07-02 | 1987-01-21 | Xerox Corporation | Impact printer |
EP0210000A1 (en) * | 1985-07-02 | 1987-01-28 | Xerox Corporation | Impact printer |
EP0207781A1 (en) * | 1985-07-02 | 1987-01-07 | Xerox Corporation | Printer impact mechanism |
US4681469A (en) * | 1985-07-02 | 1987-07-21 | Xerox Corporation | Quiet impact printer |
US4737043A (en) * | 1985-07-02 | 1988-04-12 | Xerox Corporation | Impact mechanism for quiet impact printer |
EP0226398A2 (en) * | 1985-12-05 | 1987-06-24 | Xerox Corporation | Impact printer with application of oblique print force |
EP0226398A3 (en) * | 1985-12-05 | 1988-12-14 | Xerox Corporation | Impact printer with application of oblique print force |
EP0538998A2 (en) * | 1991-10-24 | 1993-04-28 | Smith Corona Corporation | Quiet impact printer mechanism |
EP0538998A3 (en) * | 1991-10-24 | 1993-06-23 | Smith Corona Corporation | Quiet impact printer mechanism |
EP0540145A2 (en) * | 1991-10-28 | 1993-05-05 | Smith Corona Corporation | Printing mechanism with print hammer having noise dampener |
EP0540145A3 (en) * | 1991-10-28 | 1993-06-23 | Smith Corona Corporation | Printing mechanism with print hammer having noise dampener |
Also Published As
Publication number | Publication date |
---|---|
DE3071538D1 (en) | 1986-05-15 |
EP0028539B1 (en) | 1986-04-09 |
EP0028539A3 (en) | 1982-05-26 |
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