CA1108470A - Hammer for impact printer - Google Patents
Hammer for impact printerInfo
- Publication number
- CA1108470A CA1108470A CA310,369A CA310369A CA1108470A CA 1108470 A CA1108470 A CA 1108470A CA 310369 A CA310369 A CA 310369A CA 1108470 A CA1108470 A CA 1108470A
- Authority
- CA
- Canada
- Prior art keywords
- magnetic structure
- movable magnetic
- impact
- hammer
- character element
- Prior art date
- 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.)
- Expired
Links
Classifications
-
- 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
- B41J9/26—Means for operating hammers to effect impression
- B41J9/38—Electromagnetic means
-
- 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
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/22—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material
- B41J2/23—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material using print wires
- B41J2/27—Actuators for print wires
- B41J2/285—Actuators for print wires of plunger type
-
- 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
- B41J9/42—Hammer-impression mechanisms with anti-rebound arrangements
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Impact Printers (AREA)
- Electromagnets (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The hammer of a serial impact printer comprises a solenoid including a stationary magnetic structure with an opening extending therethrough and a movable magnetic structure adapted to move through the opening. The movable magnetic structure is accelerated by the flux path from the stationary magnetic structure and through the movable magnetic structure as the gap between the movable and station-ary magnetic structures closes such that the movable magnetic structure is in substantially unobstructed free flight before the impact area coupled to the movable magnetic structure strikes the character element. The character element in turn strikes a print receiving medium supported by a platen) typically through an ink-bearing ribbon.
The hammer of a serial impact printer comprises a solenoid including a stationary magnetic structure with an opening extending therethrough and a movable magnetic structure adapted to move through the opening. The movable magnetic structure is accelerated by the flux path from the stationary magnetic structure and through the movable magnetic structure as the gap between the movable and station-ary magnetic structures closes such that the movable magnetic structure is in substantially unobstructed free flight before the impact area coupled to the movable magnetic structure strikes the character element. The character element in turn strikes a print receiving medium supported by a platen) typically through an ink-bearing ribbon.
Description
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: - 2 -Backqround of the Invention This invention relates to impact printers 9 and more `. particularly, to a hammer which strikes a character element so . as to cause the character element to impact a print receiving : 5 medium juxtaposed to a support surface~
It is an object of this invention to provide a hammer for an impact printer wherein the hammer is in free flight prior to striking a character elementu It is also an object of this invention to provide a hammer for ~ impact printer which reaches the maximum hammer speed quickly.
It is a further object of this invention to minimize the cycling time for the hammer.
It is also an object of this invention to provide a : 15 hammer which will not obstruct the operator's view of the . characters ~ust printedO
It is a still further object of this invention to provide a hammer which is generally axially symmetric so as :~ to minimize manufacturing costs.
- 20 In accordance with a particular embodiment of the - invention, an impact printing apparatus comprises: a support surface adapted to support a medium for receiving print, a character element juxta~osed to said surface and adapted to be forced into contact with said print receiving medium; and . 25 hammer means including an impact area for striking said char-:i: acter element and forcing said character element toward said print receiving medium supported by said support surface, the :~ improvement residing in said hammer means comprising: a stationary magnetic structure comprising a high permeab.ility ~ 30 material, said stationary magnetic structure having an opening defining an air gap therein with said material on opposite sides thereof, a movable magnetic structure coupled to said impact area, said movable magnetic structure comprising a high permeability material and adapted to move substantially rec tilinearly through said opening so as to substantially close said air gap: said mo~able magnetic structure substantially closing said air gap and attaining a substantially constant :~ - 3 -- velocity before said impact area strikes a character element so as to permit such impact area to strike said character element while said movable magnetic structure is travelling at said substantially constant velocity in substantially fr~e flight.
The stationary magnetic structure may be substantially annular and may form a central opening extending therethrough.
The movable magnetic structure may have a slot extending parallel to the direction of linear move.ment for reducing eddy currents in the movable magnetic structure. Where the opening is circular in cross-section and the impact area is elongated or non-circular, it may be desirable to utiliæe a projection extending from the stationary magnetic structure into the slot so as to prevent rotational motion of the movable magnetic structure in the s~ot and théreby maintain the proper orien-tation of the elongated or non-circular i~pact areaO
The hammer means has a rigid elongated movable non-: magnetic member attached to the movable magnetic structure and : extending to the impact area. A coiled detent ~pring may encircle the rigid elongated non-magnetic member and contact the mova~le magnetic structure for maintaining the impact area away from the character element a~ter striking the character : element and the support surface and bouncing away therefrom.
The invention will no~ be described with reference .. 25 to the accompanyins drawings which show a preferred form thereof and wherein:
. Fig. 1 is a sectional, partially schematic view o~
a prior art hammer, Fig~ 2 is a cross-sectional, partially schematic view of a preferred embodiment of the invention;
Fig..3 is a graph illustrating the performance cha-racteristics of a hammer embodying the invention as contrasted with the hammer of the prior art, Fig. 4 is a detailed sectional view of a hammPr constructed in accordance with the principles of this invention representing the preferred embodiment thereof, and Fig. 5 is an end view of the hammer sho~n in Fig. 3.
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Heretofore, solenoids have been utilized to actuate the hammers of impact printers so as to move the impact area of the hammer toward the character element. ~ prior art hammer is depicted in Fig. 1 wherein a movable magnetic - 5 structure or plunger 12 is mounted within an axially extendiny opening 14 of a stationary magnetic structure 10. When an annular winding or coil 16 associated with the stationary magnetic structure 10 is energized, an axially extending flux path 18 is created which forces the movable magnetic structure ~ 10 12 against a ferromagnetic stop 20 which obstructs one end ; of the opening 14. The movable magnetic structure 12 is coupled to an elongated member 22 which extends from one end of the movable magnetic structure 12 through a central opening 21 in the obstruction 20 so as to allow the elongated mer~er 22 having an impact area 26 at the end thereof to strike a character element 28 juxtaposed to a support surface in the form of a platen 30.
Typically, the prior art hammer of Fig. 1 is designed such that the impact area ~6 will strike the character element 28 when the movable magnetic structure 12 is very close to the obstruction 20 at the end of the opening 14. At this moment in time, the movable magnetic structure 12 has the maximum force applied thereto and neither the movable magnetic structure 12 nor the impact area 26 at the end of the elongated member 22 is in free flight at a substantially constant velocity for the case of the hammer striking with its maximum force. To the contrary, for this case, the impact area 26 coupled to the movable magnetic structure 12 is accelerating to an ever-increasing velocity until such time as the impact area 26 strikes the character element 28.
It will therefore be understood that the prior art hammer does not reach the maximum impact velocity prior to the time that the impact area strikes the character element.
Rather, the hammer is in the process of accelerating to that velocity at the time the hammer strikes. As a consequence, the prior art ha~mers have a longer cycling time which means that the printing speed i5 not at the optimum. Moreover, the ........ ~.
~' prior art hammer will not achieve the maximum speed possible from the magnetic structure unless the impact area is properly positioned with respect to the obstruction 20 to assure that the impact area 26 strikes the character element 28 at the exact same moment that the movable magnetic structure 12 strikes the obstruction 20.
~e*erring now to Fig. 2, the preferred embodiment of the invention comprises a solenoid hammer including a stationary magnetic structure 50 comprising a high permeability material and having an axially extending opening ~8 extending there-through and a movable magnetic structure or plunger 54 .
.
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' ' ~ 6 - -1 comprlsing a high permeability material and adapted to move
: - 2 -Backqround of the Invention This invention relates to impact printers 9 and more `. particularly, to a hammer which strikes a character element so . as to cause the character element to impact a print receiving : 5 medium juxtaposed to a support surface~
It is an object of this invention to provide a hammer for an impact printer wherein the hammer is in free flight prior to striking a character elementu It is also an object of this invention to provide a hammer for ~ impact printer which reaches the maximum hammer speed quickly.
It is a further object of this invention to minimize the cycling time for the hammer.
It is also an object of this invention to provide a : 15 hammer which will not obstruct the operator's view of the . characters ~ust printedO
It is a still further object of this invention to provide a hammer which is generally axially symmetric so as :~ to minimize manufacturing costs.
- 20 In accordance with a particular embodiment of the - invention, an impact printing apparatus comprises: a support surface adapted to support a medium for receiving print, a character element juxta~osed to said surface and adapted to be forced into contact with said print receiving medium; and . 25 hammer means including an impact area for striking said char-:i: acter element and forcing said character element toward said print receiving medium supported by said support surface, the :~ improvement residing in said hammer means comprising: a stationary magnetic structure comprising a high permeab.ility ~ 30 material, said stationary magnetic structure having an opening defining an air gap therein with said material on opposite sides thereof, a movable magnetic structure coupled to said impact area, said movable magnetic structure comprising a high permeability material and adapted to move substantially rec tilinearly through said opening so as to substantially close said air gap: said mo~able magnetic structure substantially closing said air gap and attaining a substantially constant :~ - 3 -- velocity before said impact area strikes a character element so as to permit such impact area to strike said character element while said movable magnetic structure is travelling at said substantially constant velocity in substantially fr~e flight.
The stationary magnetic structure may be substantially annular and may form a central opening extending therethrough.
The movable magnetic structure may have a slot extending parallel to the direction of linear move.ment for reducing eddy currents in the movable magnetic structure. Where the opening is circular in cross-section and the impact area is elongated or non-circular, it may be desirable to utiliæe a projection extending from the stationary magnetic structure into the slot so as to prevent rotational motion of the movable magnetic structure in the s~ot and théreby maintain the proper orien-tation of the elongated or non-circular i~pact areaO
The hammer means has a rigid elongated movable non-: magnetic member attached to the movable magnetic structure and : extending to the impact area. A coiled detent ~pring may encircle the rigid elongated non-magnetic member and contact the mova~le magnetic structure for maintaining the impact area away from the character element a~ter striking the character : element and the support surface and bouncing away therefrom.
The invention will no~ be described with reference .. 25 to the accompanyins drawings which show a preferred form thereof and wherein:
. Fig. 1 is a sectional, partially schematic view o~
a prior art hammer, Fig~ 2 is a cross-sectional, partially schematic view of a preferred embodiment of the invention;
Fig..3 is a graph illustrating the performance cha-racteristics of a hammer embodying the invention as contrasted with the hammer of the prior art, Fig. 4 is a detailed sectional view of a hammPr constructed in accordance with the principles of this invention representing the preferred embodiment thereof, and Fig. 5 is an end view of the hammer sho~n in Fig. 3.
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~:~~4 `~ .
Heretofore, solenoids have been utilized to actuate the hammers of impact printers so as to move the impact area of the hammer toward the character element. ~ prior art hammer is depicted in Fig. 1 wherein a movable magnetic - 5 structure or plunger 12 is mounted within an axially extendiny opening 14 of a stationary magnetic structure 10. When an annular winding or coil 16 associated with the stationary magnetic structure 10 is energized, an axially extending flux path 18 is created which forces the movable magnetic structure ~ 10 12 against a ferromagnetic stop 20 which obstructs one end ; of the opening 14. The movable magnetic structure 12 is coupled to an elongated member 22 which extends from one end of the movable magnetic structure 12 through a central opening 21 in the obstruction 20 so as to allow the elongated mer~er 22 having an impact area 26 at the end thereof to strike a character element 28 juxtaposed to a support surface in the form of a platen 30.
Typically, the prior art hammer of Fig. 1 is designed such that the impact area ~6 will strike the character element 28 when the movable magnetic structure 12 is very close to the obstruction 20 at the end of the opening 14. At this moment in time, the movable magnetic structure 12 has the maximum force applied thereto and neither the movable magnetic structure 12 nor the impact area 26 at the end of the elongated member 22 is in free flight at a substantially constant velocity for the case of the hammer striking with its maximum force. To the contrary, for this case, the impact area 26 coupled to the movable magnetic structure 12 is accelerating to an ever-increasing velocity until such time as the impact area 26 strikes the character element 28.
It will therefore be understood that the prior art hammer does not reach the maximum impact velocity prior to the time that the impact area strikes the character element.
Rather, the hammer is in the process of accelerating to that velocity at the time the hammer strikes. As a consequence, the prior art ha~mers have a longer cycling time which means that the printing speed i5 not at the optimum. Moreover, the ........ ~.
~' prior art hammer will not achieve the maximum speed possible from the magnetic structure unless the impact area is properly positioned with respect to the obstruction 20 to assure that the impact area 26 strikes the character element 28 at the exact same moment that the movable magnetic structure 12 strikes the obstruction 20.
~e*erring now to Fig. 2, the preferred embodiment of the invention comprises a solenoid hammer including a stationary magnetic structure 50 comprising a high permeability material and having an axially extending opening ~8 extending there-through and a movable magnetic structure or plunger 54 .
.
.~.~, .=. .
,~
..
.
' ' ~ 6 - -1 comprlsing a high permeability material and adapted to move
2 rectilinearly through the a~ially extending opening 48 so as
3 to close an air gap 52~ Windings 56 encircle the movable
4 magnetic structure 54 so as to create a magnetic flux 57 through the stationary magnetic struc~ure and the mova~le ~ magnetic structure 54. M~gnetic forces associated with the 7 magnetic flux in the air gap 52 move the movable magnetic S s~ruc~ure forward toward a support surface or platen 30 wLth 9 an interposed character element 28. An impact are~ 58 is loca~ed at the end of a rigid non-magnetic elongated member 11 60 which is connected to the movable magne~ic struc~ure 54.
1~ In accordance with this invention, ~he opening 48 is 13 unobstructed so tha~ the movable m~gnetic st~ucture will 14 enter the opening 48 substantially before impacting or stri-king the cbaracter element 28 by the impact area 58.
16 Accordingly, the movable magne~ic structure 54 and the im-17 pact area 58 are in free flight at the time of striking the i8 character elemene 28.
19 Reerence will now be made to Fi~. 3~or a discussion of the advantages o the invention over the prior art. As 21 stated earlier~ it is an objective of this il~vention to 22 achieve the impact hammer speed quickly so as to minimize 23 cycling ~ime. In ~he graph shown in Fig. 3, velocity is 24 indicated on the oxdinate and position is indicated on the abscissa with the strike position shown. It will be under-26 s~ood that Fig. 3 represents the case of hammers striking 27 with their maximum strength, as for example when striking 28 a character with xelatively large area and making many car-29 bon copies. It will be noted that ~he curve i representing the veloclty versus position of the hammer of ~his lnvention `` 7 1 clearly shows that the lmpact velocity is reached by the 2 hammer very quickly and the hammer moves at a substantially 3 constan~ velocity to the strike position. In other words, 4 the hammer is in free fllght well prior to reaching the S sblke position. On the other hand, the curve p represen-6 ting the prior art veloci~y versus posi~ion illus~ra~es that -7 the velocity o~ the hammer is still increasing at the time 8 ~he hammer reaches the strike position. Accordingly, the 9 cycling time of the prior art hammer is subs~antially longer.
-- 10 Moreover~ it is clear that the prior ar~ hammer is not in 11 free 1ight at ~he time of ~he strike. Rather, furce is 12 still being applied to the hammer at the moment the hammer 13 reaches the strike position.
14 The dotted line represents the s~ri~ing position when the hammer is imprnperly located with respect to the platen 16 30. In the case of ~he prior art9 the hammer reaches the 17 strike position bef~re the hammer has reached its maximum 18 velocity, i.e., the movable magnetic structure 12 of the 19 prior art hammer never reaches the obstruction 20 at the ~ime of striking the charac~er elemen~ 28. In the case of his invention9 ~he striking velocity error due to ~he im-22 proper loca~ion is negligible.
23 Reference will now be made to Figs. 4 and 5 for a 24 detailed description of the preferred embodlment of the in-vention whereln low cost is achieved. As shown in Fig. 4, 26 the windings 56 are formed on a bobbin 62 comprislng a non- ¦
27 magnetic material. The stationary magne~ic s~ructure 50 forms 28 a h~using for the ~amm~r and encloses the windings 56. The 29 stationary magnetic struc~ure 50 Includes a sleeve 64 which extends forward toward the impac~ area 58. A sleeve-like : 1 bearing 6~ is enclcsed within the sleeve 64 to support the .
- 2 elongated member 60. An addi~ional non-magnetic bearing . 3 surface 68 guides the rear of ~he movable magnetic s~ruc-4 ~ure 54.
1~ In accordance with this invention, ~he opening 48 is 13 unobstructed so tha~ the movable m~gnetic st~ucture will 14 enter the opening 48 substantially before impacting or stri-king the cbaracter element 28 by the impact area 58.
16 Accordingly, the movable magne~ic structure 54 and the im-17 pact area 58 are in free flight at the time of striking the i8 character elemene 28.
19 Reerence will now be made to Fi~. 3~or a discussion of the advantages o the invention over the prior art. As 21 stated earlier~ it is an objective of this il~vention to 22 achieve the impact hammer speed quickly so as to minimize 23 cycling ~ime. In ~he graph shown in Fig. 3, velocity is 24 indicated on the oxdinate and position is indicated on the abscissa with the strike position shown. It will be under-26 s~ood that Fig. 3 represents the case of hammers striking 27 with their maximum strength, as for example when striking 28 a character with xelatively large area and making many car-29 bon copies. It will be noted that ~he curve i representing the veloclty versus position of the hammer of ~his lnvention `` 7 1 clearly shows that the lmpact velocity is reached by the 2 hammer very quickly and the hammer moves at a substantially 3 constan~ velocity to the strike position. In other words, 4 the hammer is in free fllght well prior to reaching the S sblke position. On the other hand, the curve p represen-6 ting the prior art veloci~y versus posi~ion illus~ra~es that -7 the velocity o~ the hammer is still increasing at the time 8 ~he hammer reaches the strike position. Accordingly, the 9 cycling time of the prior art hammer is subs~antially longer.
-- 10 Moreover~ it is clear that the prior ar~ hammer is not in 11 free 1ight at ~he time of ~he strike. Rather, furce is 12 still being applied to the hammer at the moment the hammer 13 reaches the strike position.
14 The dotted line represents the s~ri~ing position when the hammer is imprnperly located with respect to the platen 16 30. In the case of ~he prior art9 the hammer reaches the 17 strike position bef~re the hammer has reached its maximum 18 velocity, i.e., the movable magnetic structure 12 of the 19 prior art hammer never reaches the obstruction 20 at the ~ime of striking the charac~er elemen~ 28. In the case of his invention9 ~he striking velocity error due to ~he im-22 proper loca~ion is negligible.
23 Reference will now be made to Figs. 4 and 5 for a 24 detailed description of the preferred embodlment of the in-vention whereln low cost is achieved. As shown in Fig. 4, 26 the windings 56 are formed on a bobbin 62 comprislng a non- ¦
27 magnetic material. The stationary magne~ic s~ructure 50 forms 28 a h~using for the ~amm~r and encloses the windings 56. The 29 stationary magnetic struc~ure 50 Includes a sleeve 64 which extends forward toward the impac~ area 58. A sleeve-like : 1 bearing 6~ is enclcsed within the sleeve 64 to support the .
- 2 elongated member 60. An addi~ional non-magnetic bearing . 3 surface 68 guides the rear of ~he movable magnetic s~ruc-4 ~ure 54.
5 As show~ in Fig~ 5~ the elongated member 60 is :
6 circular in cross-sectiQn whereas the impact area 58 is .
7 elongated. Simllarlyj the movable magn~tic structure
8 54 is circular in cross-section. .
9 The movable magnetic struc~ure 54 includes a slot - lO 70 ex~ending parallel with the axis of the hammer. The ; 11 slot 70 acts to reduce eddy currents in the movable magnetic .
I 12 structure 54. In addition~ a pin 72 forms a projection into 13 the slo~ 70 from the magnetic bearing material 74 (or from 14 the bearing surface 68) so as to maintain the proper orien-tation for the elongated impact area 58.
16 A dash pot 76 is associa~ed with the rear of the 17 hammer. The dash pot includes a piston 78 and a spring 80 18 As the movable structure 54 and the elongated member 60 l9 is driven rearwardly af~er bouncing off the platen, air trapped in khe area 82 between the piston 78 and the housing 21 84 escapes around the piston 78 toward the non-magnetic !
22 bearing material 58 and past the screw 88 to cushion the .
23 return o~ the movable magnetic struc~ure 54. In order ~o 24 hold the impact area 58 in the re~racted position, a detent coil spring 86 is provided between the sleeve-like bearing 26 material 66 and the movable magnetic structure 54. The 27 spring 86 provides insufficient res~stance when the hammer -~ 2B is energized to substan~ially affect ~he free flight of the 29 struc~ure 54. A screw 88 controls the leakage of air which `~ 30 cushions the return of th~ structure 54 and the elongated ,,e~ 9~
member 60.
Although the printer in which the hammer of this invention has not been described in detail, it will be understood that various types of impact printers might utilize the hammer. For example~ the serial impact printer described in Canadian application Serial ~o. 311,294, and Canadian application Serial No. 303,683, are appropriate . serial impact printers for use of the hammer.
: Although a particular embodiment of the invention has been shown and describea in detail, it will be under-stood that various modifications will occur to those of ordinary skill in the art which fall within the -true spirit and scope of the invention as set forth in the appended ` claims.
.., . 1~
I 12 structure 54. In addition~ a pin 72 forms a projection into 13 the slo~ 70 from the magnetic bearing material 74 (or from 14 the bearing surface 68) so as to maintain the proper orien-tation for the elongated impact area 58.
16 A dash pot 76 is associa~ed with the rear of the 17 hammer. The dash pot includes a piston 78 and a spring 80 18 As the movable structure 54 and the elongated member 60 l9 is driven rearwardly af~er bouncing off the platen, air trapped in khe area 82 between the piston 78 and the housing 21 84 escapes around the piston 78 toward the non-magnetic !
22 bearing material 58 and past the screw 88 to cushion the .
23 return o~ the movable magnetic struc~ure 54. In order ~o 24 hold the impact area 58 in the re~racted position, a detent coil spring 86 is provided between the sleeve-like bearing 26 material 66 and the movable magnetic structure 54. The 27 spring 86 provides insufficient res~stance when the hammer -~ 2B is energized to substan~ially affect ~he free flight of the 29 struc~ure 54. A screw 88 controls the leakage of air which `~ 30 cushions the return of th~ structure 54 and the elongated ,,e~ 9~
member 60.
Although the printer in which the hammer of this invention has not been described in detail, it will be understood that various types of impact printers might utilize the hammer. For example~ the serial impact printer described in Canadian application Serial ~o. 311,294, and Canadian application Serial No. 303,683, are appropriate . serial impact printers for use of the hammer.
: Although a particular embodiment of the invention has been shown and describea in detail, it will be under-stood that various modifications will occur to those of ordinary skill in the art which fall within the -true spirit and scope of the invention as set forth in the appended ` claims.
.., . 1~
Claims (8)
1. Impact printing apparatus comprising:
a support surface adapted to support a medium for receiving print;
a character element juxtaposed to said surface and adapted to be forced into contact with said print receiving medium; and hammer means including an impact area for striking said character element and forcing said character element toward said print receiving medium supported by said support surface, the improvement residing in said hammer means comprising:
a stationary magnetic structure comprising a high permeability material, said stationary magnetic structure having an opening defining an air gap therein with said material on opposite sides thereof;
a movable magnetic structure coupled to said impact area, said movable magnetic structure comprising a high permea-bility material and adapted to move substantially rectilinearly through said opening so as to substantially close said air gap;
said movable magnetic structure substantially closing said air gap and attaining a substantially constant velocity before said impact area strikes a character element so as to permit such impact area to strike said character element while said movable magnetic structure is travelling at said sub-stantially constant velocity in substantially free flight.
a support surface adapted to support a medium for receiving print;
a character element juxtaposed to said surface and adapted to be forced into contact with said print receiving medium; and hammer means including an impact area for striking said character element and forcing said character element toward said print receiving medium supported by said support surface, the improvement residing in said hammer means comprising:
a stationary magnetic structure comprising a high permeability material, said stationary magnetic structure having an opening defining an air gap therein with said material on opposite sides thereof;
a movable magnetic structure coupled to said impact area, said movable magnetic structure comprising a high permea-bility material and adapted to move substantially rectilinearly through said opening so as to substantially close said air gap;
said movable magnetic structure substantially closing said air gap and attaining a substantially constant velocity before said impact area strikes a character element so as to permit such impact area to strike said character element while said movable magnetic structure is travelling at said sub-stantially constant velocity in substantially free flight.
2. The impact printing apparatus of claim 1 wherein said movable magnetic structure has a slot extending parallel to the direction of linear movement for reducing eddy currents.
3. The impact printing apparatus of claim 2 wherein said opening is circular in cross-section.
4. The impact printing apparatus of claim 3 further comprising a projection extending inwardly into said slot so as to prevent rotational motion of said movable magnetic structure in said space and maintain the orientation of said impact area.
5. The impact printing apparatus of claim 4 wherein said stationary magnetic structure is substantially annular.
6. The impact printing apparatus of claim 1 further comprising winding means associated with said stationary mag-netic structure, said winding means surrounding said opening.
7. The impact printing apparatus of claim 1 wherein said hammer means comprises a rigid elongated non-magnetic member extending from said movable magnetic structure to said impact area.
8. The impact printing apparatus of claim 7 compri-sing a coiled detent spring encircling said rigid elongated non-magnetic member, said detent spring contacting said movable magnetic structure for maintaining said impact area away from said character element after striking a character element and bouncing away therefrom.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US83326777A | 1977-09-14 | 1977-09-14 | |
| US833,267 | 1977-09-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1108470A true CA1108470A (en) | 1981-09-08 |
Family
ID=25263917
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA310,369A Expired CA1108470A (en) | 1977-09-14 | 1978-08-30 | Hammer for impact printer |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5453026A (en) |
| AU (1) | AU521251B2 (en) |
| BE (1) | BE870390A (en) |
| BR (1) | BR7805976A (en) |
| CA (1) | CA1108470A (en) |
| CH (1) | CH639899A5 (en) |
| DE (1) | DE2839024A1 (en) |
| FR (1) | FR2403196A1 (en) |
| GB (1) | GB2004504B (en) |
| IT (1) | IT1098621B (en) |
| MX (1) | MX4183E (en) |
| NL (1) | NL7809252A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE425068B (en) * | 1981-01-19 | 1982-08-30 | Facit Ab | PRESSURE EFFECTS |
| SE425067B (en) * | 1981-01-19 | 1982-08-30 | Facit Ab | PRESSURE HAMMER FOR PRINTERS AND PRINTERS |
| DE3116402C2 (en) * | 1981-04-24 | 1983-07-21 | Siemens AG, 1000 Berlin und 8000 München | Low rebound plunger magnet system |
| DE3116430C2 (en) * | 1981-04-24 | 1983-03-31 | Siemens AG, 1000 Berlin und 8000 München | Hammer pressure device with a plunger magnet system containing an optoelectronic sensor |
| US4429342A (en) * | 1981-04-24 | 1984-01-31 | Siemens Aktiengesellschaft | Impact printing device with an improved print hammer |
| DE3152448C2 (en) * | 1981-04-24 | 1984-09-13 | Siemens AG, 1000 Berlin und 8000 München | Plunger magnet system with high efficiency |
| US4438419A (en) * | 1982-07-28 | 1984-03-20 | International Business Machines Corporation | Serial ring actuator |
| JPS5959479A (en) * | 1982-09-29 | 1984-04-05 | Ricoh Co Ltd | Print hammer mechanism |
| DE3442223A1 (en) * | 1984-11-19 | 1986-05-28 | Olympia Werke Ag, 2940 Wilhelmshaven | Plunger-type armature magnet system having an armature which is constructed as a push rod, especially for a printing hammer device |
| JPH0434040Y2 (en) * | 1985-07-11 | 1992-08-13 | ||
| JPH0547652Y2 (en) * | 1985-11-07 | 1993-12-15 | ||
| JPH051411Y2 (en) * | 1986-02-27 | 1993-01-14 | ||
| JPS63130175A (en) * | 1986-11-13 | 1988-06-02 | エヌ・シー・アール・インターナショナル・インコーポレイテッド | Moving piezoelectric element actuator-unit |
| BE1001757A3 (en) * | 1988-06-03 | 1990-02-27 | Electronique Et Telecomm Bell | HAMMER PRINTER HEAD. |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3543906A (en) * | 1967-08-21 | 1970-12-01 | Edward J Buxton | Solenoid controlled printing hammer mechanism |
| NL7510968A (en) * | 1974-09-27 | 1976-03-30 | Bell Telephone Mfg | PRESSURE HEAD. |
| US4018155A (en) * | 1975-06-02 | 1977-04-19 | Mohawk Data Sciences Corporation | Ballistic print hammer assembly |
| DD129025A1 (en) * | 1976-09-09 | 1977-12-21 | Volker Flechtner | ELECTRODYNAMIC PRESSURE HAMMER DRIVE |
-
1978
- 1978-08-15 AU AU38906/78A patent/AU521251B2/en not_active Expired
- 1978-08-30 CA CA310,369A patent/CA1108470A/en not_active Expired
- 1978-08-30 MX MX787364U patent/MX4183E/en unknown
- 1978-08-31 GB GB7835229A patent/GB2004504B/en not_active Expired
- 1978-09-07 DE DE19782839024 patent/DE2839024A1/en not_active Withdrawn
- 1978-09-08 FR FR7825953A patent/FR2403196A1/en not_active Withdrawn
- 1978-09-11 NL NL7809252A patent/NL7809252A/en not_active Application Discontinuation
- 1978-09-12 BE BE2057267A patent/BE870390A/en not_active IP Right Cessation
- 1978-09-13 IT IT27633/78A patent/IT1098621B/en active
- 1978-09-13 BR BR7805976A patent/BR7805976A/en unknown
- 1978-09-14 CH CH962078A patent/CH639899A5/en not_active IP Right Cessation
- 1978-09-14 JP JP11244078A patent/JPS5453026A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| BR7805976A (en) | 1979-05-29 |
| MX4183E (en) | 1982-01-20 |
| GB2004504A (en) | 1979-04-04 |
| GB2004504B (en) | 1982-02-24 |
| DE2839024A1 (en) | 1979-03-22 |
| BE870390A (en) | 1979-03-12 |
| FR2403196A1 (en) | 1979-04-13 |
| JPS5453026A (en) | 1979-04-26 |
| AU521251B2 (en) | 1982-03-25 |
| IT1098621B (en) | 1985-09-07 |
| AU3890678A (en) | 1980-02-21 |
| NL7809252A (en) | 1979-03-16 |
| IT7827633A0 (en) | 1978-09-13 |
| CH639899A5 (en) | 1983-12-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |