| US3220276A | 1965-11-30 | |||
| US3270854A | 1966-09-06 | |||
| US3499336A | 1970-03-10 | |||
| US3835976A | 1974-09-17 | |||
| US3854418A | 1974-12-17 | |||
| US3884339A | 1975-05-20 | |||
| US3935936A | 1976-02-03 | |||
| US3960256A | 1976-06-01 | |||
| US3974906A | 1976-08-17 | |||
| US4086997A | 1978-05-02 | |||
| US4134695A | 1979-01-16 | |||
| US4174908A | 1979-11-20 | |||
| NL7509526A | 1976-02-17 | |||
| DE2838627A1 | 1979-03-22 | |||
| US3983803A | 1976-10-05 | |||
| US4011932A | 1977-03-15 | |||
| US4019616A | 1977-04-26 | |||
| US4034842A | 1977-07-12 | |||
| US4044882A | 1977-08-30 |
| 1. | Apparatus for moving a printing assembly in a printer comprising: first and second elongated guide members; a carriage assembly having first and second guide ways for slidably receiving said first and second elongated guide members; small, lightweight bidirectional motor means being mounted upon said carriage assembly and adapted to rotate in a first direction when receiving a first type of motor control signal and in a second direction opposite said first direction when receiving a second type of motor control signal different from said first type of motor control signal; rotary drive means rotatably mounted upon said carriage assembly and coupled to said motor means to rotate in a forward drive direction when said motor means is rotating in said first direction and in a reverse drive direction when said motor means is rotating in said second direction; the periphery of said drive means being immediately adjacent to said first guide member; said first guide member having a predetermined surface configuration extending along the length of said first guide member and parallel to the longitudinal axis of said first guide member; the periphery of said drive means having a surface configuration which engages said predetermined surface configuration of said first guide member; the surface configuration of said drive means being designed to intimately rollingly engage the pre¬ determined surface configuration of said first guide member to assure that the rotary means does not experience any slippage relative to the predetermined surface of said first guide member as the drive means rotates to provide positive nonslip traction for moving said carriage along said first and second elongated guide members. glJRiA r . |
| 2. | The apparatus of Claim 1 wherein said rotary drive means comprises a cylindricalshaped member having a roughened peripheral surface. |
| 3. | The apparatus of Claim 2 wherein the predetermined surface of said elongated guide member comprises a roughened surface complementary to the roughened surface of said rotary drive means to prevent said rotary drive means from slipping relative to the roughened surface of said first elongated guide means as the rotary drive means rotates . |
| 4. | The apparatus of Claim 1 wherein said rotary drive means comprises a pinion gear, the surface of said pinion gear comprising gear teeth arranged around the periphery of the pinion gear. |
| 5. | The apparatus of Claim 4 wherein said predetermined surface of said first elongated guide means comprises a rack having gear teeth adapted to be engaged by the gear teeth of said pinion gear as the pinion gear rotates . |
| 6. | The apparatus of Claim 1 wherein said first elongated guide member comprises a guide shaft, said predetermined surface comprising a rack arranged along the surface of said guide shaft parallel to the longitudinal axis of the guide shaft and having gear teeth adapted to be engaged by the gear teeth of said pinion gear. |
| 7. | The apparatus of Claim 6 wherein said motor means comprises a DC motor. |
| 8. | The appartus of Claim 1 further comprising timing means mounted on said carriage assembly responsive to operation of said motor means to generate timing signals at predetermined time intervals wherein the time intervals between timing signals control the operation of the printing means being moved by said carriage assembly. |
| 9. | The apparatus of Claim 8 wherein said timing means comprises a timing member being rotated responsive to rotation of said motor means, coded pattern means arranged around the periphery of said timing member; sensor means positioned adjacent to said timing means and responsive to movement of said coded pattern means for generating said timing signals. |
| 10. | The apparatus of Claim 9 wherein said coded pattern means comprises permanent magnet means; said sensor means comprises means responsive to the movement of the magnetic fields produced by said permanent magnet means past said sensor means to generate said timing pulses. |
| 11. | The apparatus of Claim 10 wherein said sensor means comprises a Hall effect sensor. |
| 12. | The apparatus of Claim 1 further comprising adapter means and means for slidably mounting said adapter means upon said carriage assembly along a predetermined direction; cam means positioned between said adapter means and said carriage assembly and being movable for adjusting the position of said adapter means relative to said carriage assembly. so¬ ls. |
| 13. | The apparatus of Claim 12 wherein said cam means comprises spring means positioned between said carriage assembly and said adapter means for urging said adapter in a first direction along said predetermined path relative to said carriage assembly; a cam adjustment member having a rotatable portion mounted upon said carriage assembly and having a cam secured to said rotatable member; said adapter means having a clearance opening through which said cam adjustment member extends and having a surface engageable by said cam for adjusting the position of said adapter means relative to said carriage assembly. |
| 14. | The apparatus of Claim 13 further comprising second cylindricalshaped adjustment means rotatably mounted upon said carriage asembly and having an opening for receiving and rotatably supporting the rotatable member portion of said cam adjustment member, the opening in said second cylindricalshaped adjustment means being located at a position offset from the central axis of said second cylindricalshaped cam adjustment means, whereby said cam adjustment member and said cylindricalshaped cam adjustment means are independently adjustable. |
| 15. | The apparatus of Claim 1 further comprising adapter means slidably mounted upon said carriage assembly, said carriage assembly having a dovetailshaped groove; said adapter means having a dovetailshaped projection slidably received by the groove on said carriage assembly; said adapter means including a rear wall ; said print head means having a flat portion adapted to rest against one surface of said rear wall; and fastening means for securing said print head means to said rear wall. |
| 16. | The apparatus of Claim 15 wherein said print head means further comprises a forward portion extending to the forward end of said adapter means; a plurality of rotatably mounted roller guide members for guiding an inked ribbon about the forward end of said adapter means so as to guide the ribbon into a substantially Ushaped configuration causing the ribbon to move past the free end of forward portion of the print head means and guiding the ribbon a predetermined distance rearwardly on both sides of the front end of said print head means . |
| 17. | The apparatus of Claim 15 wherein said print head means is further comprised of a plurality of print v.'ires and print wire driving means ; cable means including a plurality of conductors having one end electrically connected to said print wire driving means; said rear wall including a plurality of rear¬ wardly extending projections located adjacent to the periphery of said print head means for retaining said cable means in a predetermined contour between the said projections and the print head means. |
| 18. | The apparatus of Claim 1 wherein said motor means includes an output gear adapted to rotate upon rotation of said motor means; a gear train comprised of a plurality of gear members rotatably mounted upon said carriage assembly for coupling rotation of said motor output gear to said rotary drive means . |
| 19. | The apparatus of Claim 18 wherein said gear train comprises a first intermediate gear adapted to mesh with said motor output gear; a second intermediate gear having a large diameter gear portion meshing with said first intermediate gear and having a small diameter gear portion integral with said large diameter gear portion; said rotary drive means comprising a large diameter gear portion meshing with the small diameter gear portion of said second intermediate gear; Q said surface configuration of said rotary drive means comprising a drive portion integral with the large diameter gear portion of said rotary drive means . |
| 20. | The apparatus of Claim 18 further comprising a code pattern member being integral with said first 5 intermediate gear; sensor means; bracket means on said carriage assembly for positioning said sensor adjacent to said code pattern member. |
| 21. | o. |
| 22. | The apparatus of Claim 1 further comprising a margin sensing element having a stationary first end and a resilient arm extending outwardly from said stationary end.; a sensor element; a permanent magnet fixed to the free end of said resilient arm; said free end normally positioning said permanent magnet adjacent to said sensor; said carriage assembly having a projection extending toward said resilient arm for engaging said resilient arm at a point spaced inwardly from said free end whereby movement of said carriage assembly in said second direction causes said projection to urge said resilient arm to bend and thereby move said permanent magnet away from said sensor. |
| 23. | __•. |
| 24. | Apparatus for moving a print assembly in a printer comprising: first and second elongated guide members; a carriage assembly having first and second guide ways for slidably receiving said first and second elongated guide members; light weight, bidirectional motor means being mounted upon said carriage assembly and adapted to rotate in a first direction when receiving a first type signal and in a second direction opposite said first direction when receiving a second type of signal different from said first type of signal; rotary drive means rotatably mounted upon said carriage assembly and coupled to rotate in a forward drive direction whe said motor means is rotating in said second directio ; means engaged from moving said carriage assembly along said guide members; timing means mounted on said carriage assembly responsive to rotation of said motor means generating timing signals for wherein the time intervals between the timing signals control the operation of the printing means being moved by said carriage assembly. |
TECHNICAL FIELD
The present invention relates to printers and more particularly to a rugged highly-reliable printer of simplified design which is inexpensive to manufacture, assembly, disassemble, and operate. The employment of a self-propelled reciprocating carriage means upon which the printing means is mounted provides positive non-slip movement of the carriage means during printing. BACKGROUND OF THE INVENTION
Modern-day printers have been designed with a view toward both speed and simplicity. One of the most effective techniques employed for design simplification is to reduce the number of moving parts within the printer to a practical minimum. For example, the traditional recipro¬ cating platen has been replaced by a stationary platen and the traditional swingably movable type fonts have been replaced by a movable print head arranged to move across the stationary platen during printing.
Since the printing mechanism is constantly moving during a printing operation, it is desirable to reduce the size and weight of the printing mechanism with a view toward increasing printing speed as well as reducing the power requirements and the size, complexiity and cost of the drive means for moving the printing means across the platen. Typically, the printing means, which may, for example, be comprised of a print head of the dot matrix impact type, is mounted upon a carriage which is movable along guide rails to assure proper alignment of the print head as it sweeps across the platen during printing. Linear driving movement is imparted to the print head and print head carriage by a motor mounted to the printer frame and coupled to the carriage by a drive belt or other suitable drive train. In unidirectional printers, at least one clutch is provided to drive the carriage in the forward
direction, enabling the printer to return to the left-hand margin under the control of a return spring. Alternatively, both forward and Reverse clutch means may be provided to couple opposite output rotations of the motor to the printing means carriage. A brake is also required in order to prevent the head to be stopped at any position between the left and right-hand margins.
As a further alternative, the return spring and/or clutches may be eliminated with the use of a bidirectional motor. Although the above techniques are satisfactory for moving a print head and in fact, con¬ stitute state of the art technology, it is nevertheless ' desirable to further simplify the design of the drive chain and/or eliminate one or more of its components or assemblies to reduce cost and increase reliability of the printer.
DISCLOSURE OF THE INVENTION
The present invention achieves the objectives referred to above through the employment of a self- propelled carriage assembly characterized by comprising a light weight and yet rugged carriage mounted for recipro¬ cating slidable movement along a pair of carriage rails, one of which rails incorporates an elongated rack. A DC motor of extremely small size, light weight and low output power is mounted directly upon the carriage. Control signals are coupled thereto by means of a flexible cable, preferably of the flexible flat cable printed circuit type.
The output shaft of the motor drives a gear train which meshes with the rack to impart positive non-slip drive to the carriage in both the forward and reverse directions, thereby eliminating all pulleys, belts, clutches and springs required in printers of conventional design.
The motor output also rotates a permanent magnet member which is coupled to the motor output through
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a suitable gear train. Hall effect sensor mounted on the carriage senses the rotating magnetic fields to generate registration pulses employed to accurately position the printed patterns in precise registry upon the print receiving medium, typically a paper web, supported by a platen.
The print head, preferably of the dot matrix impact type, is mounted upon a mounting bracket which, in turn, is slidably mounted upon the carriage. Print head positioning cam means is rotated by manipulation of its operating handle to position its cam surface relative to a cam follower surface provided on the print head mounting bracket to precisely locate the nose of the print head relative to the platen surface employed to support the print receiving medium.
The vast majority of the carriage assembly and drive components are formed of a rugged light weight plastic material to provide low sliding friction between moving parts and to significantly reduce the total mass of the assembly thereby producing the power needed for propelling the carriage assembly.
OBJECTS OF THE INVENTION AMD BRIEF DESCRIPTION OF THE FIGURES
It is therefore one object of the present invention to provide a novel self-propelled carriage assembly for use in printers and the like.
Another object of the present invention is to provide a novel reciprocating carriage assembly for printers and the like and which is provided with a small , light weight, low power bidirectional type motor for imparting selective rotational movement to a gear train which meshes with an elongated rack to impart positive, non-slip drive to the carriage assembly.
Another object of the present invention is to provide a novel carriage assembly for printers and the like
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in which a print head mounting bracket is slidably supported thereon for simple straightforward adjustment of the print head relative to the printer platen.
Still another object of the present invention 5 is to provide a novel carriage assembly for printers and the like in which a light weight, compact gear train is provided for coupling drive from a small size light weight carriage mounted motor to a rack gear for moving said carriage and for rotating registration means adapted to 0 generate timing pulses for assuring precise registry of the printed matter upon the print receiving medium.
The above as well as other objects of the present invention will become apparent when reading the accompanying description and drawings in which: 5 Figure la is a top plan view of a print head and carriage assembly embodying the principals of the present invention.
Figures lb, lc and Id are left-hand side, rear and front elevational views of the assembly of Figure la. o Figure le is a top plan view of Hall effect sensor mounting of Figure 1.
Figure If is a bottom plan view of the Hail effect sensor mounting.
Figure lg is a front view of the spur gear rotor. 5 Figure lh is a sectional view of the spur gear rotor of Figure lg.
Figure 2a is a right-hand side elevational view of the carriage member in the assembly of Figure la.
Figure 2b shows a sectional view of the carriage Q assembly and print head mounting bracket of Figure la.
Figure 3a is a top plan view of the print head adapter employed for mounting the print head upon the carriage assembly of Figure la.
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Figures 3b, 3c and 3d are right-hand side elevational, front elevational and rear elevational views, respectively of the print head adapter of Figure 3a.
Figure a shows a top plan view of the carriage of Figure la.
Figures 4b, 4c, 4d and 4e are front elevational right-hand side elevational , rear elevational and left-hand side elevational views, respectively of the carriage of Figure 4a. Figure 4f shows a sectional view of the carriage taken along the lines 4f-4f of Figure 4d.
Figure 4g is a detailed view of the top portion of the carriage.
Figure 5a shows a top plan view of the print head adjustment cam employed in the print head assembly of Figure la.
Figure 5b is a side elevational view of the print head adjustment cam of Figure 5a.
Figure 5c is a section taken along line 5c-5c of Figure 5b.
Figure 6a is a side view of a second adjustment cam employed with the adjustment cam of Figure 5a.
Figure 6b is a top plan view of the second adjustment cam of Figure 6a. Figures 7a and 7b are top and side elevational views of the Hall effect actuator utilized at a margin detection device.
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DETAILED DESCRIPTION OF THE INVENTION INCLUDING PREFERRED MODE FOR CARRYING OUT THE INVENTION
Considering Figures la-Id, there is shown therein a print head and carriage assembly 10 comprised of three primary subassemblies, namely a carriage assembly 11 shown in detail in Figures 4a-4f; a head adapter 12 shown in detail in Figures 3a-3d; and a print head 13 shown in detail in Figures la-Id and described in detail in appli- cant's copending United States application (M-8485) Serial No. 772,459, filed February 28, 1977, and assigned to the assignee of the present invention. For purposes of the present invention, it is sufficient to understand that the print head is a dot matrix impact type print head capable of printing dot patterns typically in adjacent dot columns, five (5) or nine (9) such columns collectively forming a character, each column having between one (1) and seven (7) dots. Although the present invention is advantageous for use with print heads of the dot matrix impact type, the present invention may be advantageously employed with any other type of print ' head such as, for example, print heads of the electrostatic type, of the thermal type, of the ink jet type, and so forth.
Considering, for example, Figure lb, the print head and carriage assembly are guided by and are adapted to slide along a pair of guide rods 14 and 15 which are arranged in spaced parallel fashion between a pair of side plates, not shown ' in the drawings for purposes of simplicity. A detailed description of the carriage frame and supporting assembly is set forth in copending United
States ap p lication Serial No. 040.911 filed Mav 21, 1979 (Centronics 3.0-039), and for purposes of the present invention, it is sufficient to understand that the guide rods are a pair of elongated cylindrical-shaped rigid metallic rods secured to and supported by a pair of left and right-hand side plates as shown, for example, in Figure 1 of the last-mentioned copending application Serial No.
040,911. The rods may be any shape other than cylindrical and may even be rails, if desired. Positioned along the top surface of guide rod 15 is an elongated member 15 shown best in Figures la, lb and lc and having a set of uniformly spaced teeth 16a arranged along the top surface thereof forming a rack whose gear teeth make meshing engagement with the gear teeth of a pinion gear, to be more fully described hereinbelow, for purposes of moving the carriage along the guide rods in both- a forward (i.e. left to right) and reverse (i.e. right to left) direction .
Considering Figures 4a-4f together with Figures la-le, the carriage assembly is comprised of an L-shaped body 17 having a horizontally aligned portion 17a and a vertically aligned portion 17b. Portion 17a serves as - the means for slidably receiving and mounting the print head adapter 12 which supports print head 13, while the vertically aligned portion 17b serves as the means for rotatably mounting the drive motor 18 and the gear cluster associated therewith and which will be more fully described.
The lower end of the vertically aligned body portion 17b of carriage 11 is provided with a pair of substantially keyhole-shaped projections 18 and 19, each having a keyhole-shaped opening 18a,- 19a, respectively wherein the lower circular portion of each keyhole-shaped openings 18 and 19 is adapted to slidably receive and be guided by carriage guide shaft 15 while the upper rectangular-shaped portion of the openings 18 and 19 are adapted to slidably receive the rack member 16 with sufficient clearance along the upper horizontal edge of the rectangular-shaped opening so as to permit freely slidable movement of the carriage relative ' to the carriage guide shaft 15 and rack 16. The carriage member 17 . is formed of a material which provides extremely low sliding friction, such as polycarbonate mixed with polytetrafluoroethylene.
The forward end of the horizontally aligned
portion 17a of carriage member 17 is provided with an annular-shaped projection 20 having an oblong or oval- shaped opening 20a for slidably receiving the upper carriage guide shaft 14 and is adapted to provide sufficient clearance to allow for tolerance in the fit as between the spaced parallel arrangement of the carriage guide shafts 14 and 15 and the lower openings 18a-19a and upper opening 20a. The oval shape also reduces the surface contact area between the peripheral surface of shaft 14 and the inner surface oval-shaped opening 20a.
The top surface 21 of the horizontally aligned body portion 17a is provided with a dovetail-shaped slot 22 comprised of a base or bottom surface 22a and diagonally aligned sides 22b and 22c, respectively as shown best, for example, in Figure 4b. The dovetail-shaped slot 22 is adapted to slidably receive a similar dovetail-shaped projection (to be more fully described) provided on the head adapter 12 as will be more fully described.
As shown best in Figure 4g, the center portion of the base 22a of groove 22 is provided with a tapered triangular-shaped projection 23 having a curved top surface 23a which is adapted to be slidably received within a similar shaped slot (to be more fully described) provided in the head adapter 12. The top surface 21 of the carriage member 17 is further provided with a vertically aligned opening 24 shown best in Figures 4a and 4b, opening 24 extending completely through the horizontally aligned portion 17a of carriage assembly 17. A horizontally aligned threaded opening 25 communicates with opening 24. Opening 24 is • adapted to receive first and second print head adjustment cams shown in Figures 5a-5b and 6a-6b, which adjustment cams will be more fully described hereinbelow.
The rearwardly directed surface of the vertically aligned portion 17b of carriage assembly 17 is provided
with a shallow recess 26 containing openings 27 and 28. A portion of the rear surface extends in the upper right-hand direction and forms a motor and gear mounting portion 29 having an opening 30 through which the shaft and shaft bearing of motor M extends. Openings 31 and 32 on diametrically opposing sides of opening 30 are adapted to receive mounting rivets of motor M as will be more fully described.
Openings 31 and 32 are two of a cluster of openings whose centers lie on an imaginary circle and further including openings 33, 34, 35 and 36. Openings 31 and 32, as well as openings 33-35 serve as motor vent holes to provide adequate air-cooling for the motor as will be more fully described. Opening 36 serves as a rotor gear shaft mounting opening as will be more fully described.
The openings 30-36, as well as the openings 27 and 28 extend through portion 17b as can be seen from the front elevational view cf Figure 4b.
The upper right-hand corner of motor mounting portion 29 is further provided with an opening 37 arranged within a recess 38 having a floor 38a arranged between a pair cf spaced parallel projections 39 and 40 whose inner edges 39a and 40a align and slidably receive the like- shaped projection of a sensor mounting bracket, to be more fully described in connection with Figures le and If.
Figures le and If show a mounting bracket 41 for mounting a Hall effect sensor 42 to carriage member 17. Bracket 41 is provided with a rectangular-shaped projection 41a arranged along its undersurface for slidable insertion into the recess 38 defined by the floor 38a and side walls 39a and 40a shown best in Figure 4d. An elongated opening 41b is provided for receiving a threaded fastening member 43 which extends through elongated opening 41b and is secured into threaded opening 37 of the carriage assembly. The main body portion of the Hall effect sensor
mounting bracket 41 is provided with an outwardly extending generally U-shaped projection 41c defining a pair of arms 41d and 41e. Arms 41d and 41e have shoulders 41f and 41g, respectively which, together with diagonally aligned side walls 41h and 4lj , form a substantially dovetail-shaped groove into which the Hall effect sensor element 42 is resiliently embraced, arm 41e being resilient and being capable of yielding somewhat to provide a good force-fit of the Hall effect sensor element 42 between the arms 4le and 41f.
A flat flexible printed circuit cable 43 is provided with electrical • leads 43a, 43b and 43c for electrically coupling the electrodes of the sensor element to peripheral circuitry mounted remote from the carriage assembly, terminals 43b and 43c being adapted to connect electrical power to the Hall effect sensor element and conductor 43a being adapted to couple the output of the Hall effect sensor element to an electrical circuit, remote from the carriage assembly, as will be more fully described. As can best be seen in Figure Id, the printed circuit cable 43 is twisted through a 90 angle at 43d and extends along a portion of the periphery of the rear cover or parasol 44 of the print head 13 and merges with additional conductors provided upon a widened portion of the flat flexible printed circuit cable, as will be more fully described.
Figures la, lb and lc show the motor M as being mounted on the front surface of carriage member 17 and having a motor output shaft 45 extending rearwardly and through opening 30 as shown best in .Figures Id and 4f. A pinion gear 46 is mounted upon motor shaft 45 and meshes with a gear portion 47a forming an integral part of the rotor spur gear assembly 47 shown best in Figures Id, lg and lh as being comprised of a plastic member having a narrow diameter portion forming gear 47a and a larger
diameter portion embraced by two substantially semicircular- shaped magnet assembly members 48a and 48b secured about the larger diameter circular portion 47b which is provided with an outermost hexagonal-shaped flange 47c. Each semicircular-shaped member has a plurality of small permanent- magnets embedded therein with their magnetic poles arranged to develop magnetic flux fields for influencing sensor 42. Member 47 is mounted for rotation upon a shaft 49 so as to be driven into rotation as a result of the meshing relationship between the respective gear teeth of motor pinion gear 46 and rotor spur gear portion 47a of the rotor spur gear assembly 47.
The rotor spur gear portion 47a also meshes with a large diameter gear member 50a which is integrally joined to a small diameter gear portion 50b, of a two-gear member 50 which mounted to rotate upon shaft 51 which shaft extends into opening 28 of carriage member 17 as shown best in Figure 4f .
A second two-gear member 52 is comprised of a large diameter gear portion 52a which meshes with small diameter gear portion 52b and which is integrally formed with small diameter gear portion 52b hereinafter referred to as a pinion gear. The teeth of pinion gear 52b mesh with the teeth 16a of elongated rack 16 for the purpose of imparting positive non-slip movement of the carriage 11 and hence print head 13, relative to rack 16.
As shown best in Figures la and lc , the forward end 53 of motor M is provided with a pair of electrical terminals 54 and 55 having the typical polarities as shown by the symbols (+) and (-) . Electrical terminals 54 and 55 are adapted to be inserted within openings provided in a pair of connecting terminals 56 and 57 provided in portion 43f of flat flexible printed circuit cable 43. The cable portion 43f generally follows the contour of the print head assembly 13 and extends upwardly toward a flexible printed
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circuit cable mounting bracket which is secured to the head adapter assembly 12, as will be more fully described.
The print head adapter 12 shown in Figures la-Id as shown in further detail in Figures 3a-3d and is comprised of a body portion having a dovetail-shaped projection 61 extending downwardly from the underside thereof and defined by a pair of diagonal sides 61a and 61b which are slidably received within the dovetail-shaped groove 22 shown best in Figures lc and 4g. The underside of projection 61 is provided with a generally triangular- shaped groove 61c having a curved base portion and adapted to slidably receive a similar shaped base portion 23 provided at the center of dovetail-shaped groove 22, also shown in Figures lc and 4g. This interlocking relation- ship prevents the head adapter from experiencing any side wise movement relative to carriage member 17 while enabling the head adapter to be slidable along the center line 64 shown, for example, in Figure la which enables precision adjustment of the nose of print head assembly 13 relative to a platen member (to be more fully described) .
The rear end of body member 60 is provided with a mounting portion 62 whose lower ends 62a and 62b are integrally joined to the rear end of body portion 60. The print head mounting portion 62 is provided with openings 65 and 66 for receiving fastening members 67 and 68 as shown best in Figures la, lb and 2a, which fasteners threadedly engage tapped openings within the solenoid mounting disc 70 of print head assembly 13, as will be more fully described. The upper right-hand portion of print head mounting portion 62 is provided with an integral rearwardly extending elongated projection 62c which extends along a portion of the periphery of parasol 44 as shown best in Figure Id so as to provide a narrow gap space G through which the flat flexible cable printed circuit 43 and elongated leads L extend to maintain the printed circuit
cable 43 and leads L in position in an orderly arrangement and thereby prevent the cable 43- and leads L from experiencing any unnecessary movement and hence possibly displacement as a result of the continuous reciprocating movement of the print head during operation of the printer. Immediately above the elongated projection 62c there is provided a second rearwardly extending integral projection 62d having bifurcated arms 62e and 62f defining a slot 62g therebetween which slot is adapted to receive a threaded fastening member 63 designed to secure the triangular-shaped body 64a of a flexible cable printed circuit supporting member 64 having a pair of rearwardly extending cylindrical shaped projections 64b and 64c which serve to retain the flat flexible printed circuit cable 43 and lead lines L in a neat orderly arrangement as shown best in Figures la and Id.
The printed circuit cable has a sharp bend at 43g shown in Figure Id. The portion 43h of the printed circuit cable extends from- bend 43g toward the periphery of print head assembly 13 and encircles the generally circular shaped periphery and provides electrical terminals 43k for connection with the pair of terminals I3d-1 of each solenoid winding 13d of the print head 13. All of the electrical connections between the Hall effect sensor element 42, motor M and solenoid .windings 31d of the print head 13, extend from the flat flexible cable printed circuit wiring 43 to a portion of the printed circuit wiring cable which electrically connects all of the conductors extending through the flat flexible printed circuit cable 43 to a dual-in-line printed circuit connector 66 of the socket type and having first and second rows of openings adapted to receive electrically extending leads or terminals (not shown) from a connector member 67 of the dual-in-line package plug connector type and having a plurality of electrical leads L extending outwardly from
one side of connector 67 , each lead L being comprised of a conductor (not shown) within an insulating sleeve, which leads L extend to a similar dual-in-line connector 68 of the plug type. The leads L are resilient (i.e. bendable) and are of a length sufficient to allow the carriage assembly to move freely between the left and right-hand margins of the printer without placing any stress upon leads L. The plug connector 68 is adapted to be plugged into a connector of the control electronics located in the printer remote from said carriage assembly.
The- forward end of body 60 has integrally joined thereto a pair of forwardly extending ribs 72 and 73 whose free ends extend generally vertically upward, as can best be seen in Figure 3b, to form a pair of inked ribbon roller supports 72a, 73a. A spanning rib 75 is integrally joined to the upper ends of vertically extending portions 72a and 73a and is provided with a pair of openings 75a and 75b for receiving a pair of pins 76, 77 shown best in Figures la and lb. The pins 76 and 77 extend through openings 75a an< 75 b as well as through openings 78 and 79 in forwardly extending projections 80 and 81 integral with the lower forward ends of upright portions 72a and 73a, respectively. Each of the pins 76 and 77 rotatably supports a free- wheelingly mounted roller 84, 85 shown best in Figures la and lb. The portions 72a, 73a and 75 prevent the ribbon from running off the rollers 84 and 85.
Body member 60 is provided with a pair of openings 60d and 60e, opening 60d being to the rear of and to the left of opening 75a while opening 60e is to the rear of and to the right of opening 75b as shown best in Figure 3a. Each of these openings is adapted to receive and rotatably support a f eewheelingly mounted roller 88, 89 shown best in Figures la, lb and lc , which are secured to the openings 60d and 60e by means of mounting pins 91 and 92 whose bottoms are secured in openings 60d and 60e.
Mounting clips 94 and 95 serve to prevent the rollers 88 and 89 from being removed from their mounting pins 91 and 92. Rollers 88 and 89 each have flanges 88a, 88b and 89a, . 89b which retain the ribbon therebetween. The rollers 84, 85 , 88 and 89 are designed to guide the inked ribbon R (see Figure la) along a generally U-shaped path wherein the rollers 84 and 85 are substantially aligned with the nose of the print head to allow the inked ribbon R to move across the nose of the print head during printing, while rollers 88 and 89 are provided to guide the inked ribbon rearwardly relative to the nose of the print head in order to allow material already printed upon the paper document to be exposed to view shortly after printing and also to prevent the inked ribbon from possibly smearing the print receiving medium.
The top surface of the body 60 of the head adapter 12 is provided with a recess 60f with a perimeter defined by a plurality of upright sides 60g-l through 61g-10, selected ones of which are adapted to cooperate with the head adjustment cam 98 shown in Figures 5a and 5b as well as Figures la and lb. A large diameter opening 60h extends through body 60 and is adapted to receive the lower end of print head adjustment cam 98 as well as the upper end of second print head adjustment cam 99 shown best in Figures lb, 6a and 6b. Opening 60h provides clearance for cam 99 to permit the adapter 12 to move relative to carriage member 17.
Considering Figures 6a and 6b, the second print head adjustment cam 99 is a substantially cylindrical shaped member 99a having an opening 99b extending completely through the body thereof. One end of cylindrical-shaped cam member 99 is provided with a hexagonal-shaped periphery 99c adapted to facilitate gripping and adjustment. As can best be seen from a consideration of Figure 6b, opening 99b is eccentrically
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located relative to the central axis of member 99 thereby providing a measure of adjustment of the print head 13 relative to a platen 105 as will be more fully described. The second print head adjustment cam member 99 is positioned beneath body 60 and has its cylindrical portion extending into opening 60h in main body 60.
The print head adjustment cam 98 has a manually operable handle 98a joined to a cylindrical-shaped portion 98b, a cam-shaped portion 98c is arranged near the lower end of a cylindrical portion 98b which merges with a smaller diameter cylindrical portion 98d. The cam-shaped member is provided with a number of side surfaces 98e-l through 98e-7. The merger between side surfaces 98e-l and 98e-2 is finished off with a smooth curve at 98f. The print head adjustment cam 98 is rotatable within the opening 99b provided in second print head adjustment cam 99 and, depending upon which facet 98e-l thorugh 98e-7 of adjust¬ ment cam 98 engages forwardmost upright surface 60g-7 of recess 60f, is determinative of the position of the head adapter 12 and print head 13 relative to the carriage 11.
As can best be seen from a consideration of Figure 2b, the underside of main body portion 60 is provided with a downwardly depending projection 60k. One end of a helical spring 102 bears against projection 60k while the opposite. end of spring 102 bears against the forward edge 22c of the dovetail-shaped recess 22 provided in the body portion 17 of carriage 11. Note especially Figures 2a, 3a, 3b and 4a. Helical spring 102 normally urges print head adapter 12 in a rearward direction relative to carriage 11 as represented by arrow 103 in
Figure 2a. The rotation of print head adjustment cam 98 by manipulation of its manually operable handle 98a, serves to control the relative position of the head adapter 12 relative to the carriage 11 thereby providing the means for adjusting the nose of the print head relative to the platen
of the printer. Note, for example, Figure 2a which shows the platen 105 as supporting a paper web 106. An inked ribbon R is positioned between the nose N of the print head and the paper web 106. The. relative positions of the inked ribbon R, paper 106 and platen 105 have been grossly exaggerated, it being understood that the spacing between the surface of platen 105 and the nose of the print head is typically of the order of 0.010 to 0.020 inches.
In addition to the "coarse" adjustment, rotation of the second cam member 99 provides an additional "fine" adjustment of the position of the nose N of the print head relative, to platen 105. Once the nose N of the print head is precisely located at the desired position, this position may be maintained by tightening threaded member 108 arranged within the tapped aperture 24a provided in the horizontally aligned body portion 17a of the carriage member 11 so as to enable the forward end of the threaded member to firmly engage the peripheral surface of cylindrical body portion 99a and thereby retain the print head in the desired position after completion of the precision adjustment operation .
Figures la, lb and 2a show the manner in which the print head assembly 13 is mounted to the head adapter 12. As was previously described, threaded fasteners 67 and 68 extend through openings 65 and 66, respectively of head adapter 12 and extend into tapped opening within the circular disc 70. A plurality of solenoid assemblies 111 each have a first end thereof joined to solenoid mounting disc 70. As is set forth in detail in copending application Serial No. 772,459 (M-8485), each solenoid assembly is comprised of a solenoid winding 13d and a magnetic core I3e adapted to concentrate magnetic flux developed by the solenoid vjinding 13d when energized, into a rearward region wherein a cooperating armature Ilia is provided. The " armature is drawn toward its associated magnetic core in
order to urge a print wire associated therewith forwardly so as to impact -against inked ribbon R and paper 106 in order to transfer ink from inked ribbon R in the form of a dot onto paper web 106. Each of the solenoid windings 13d is provided, as is conventional, with a pair of end terminals 13d-l and l3d-2 adapted to be connected to the terminals 114 and 115, respectively provided in the printed circuit portion 43k arranged to encircle the solenoid assemblies 111. As is described in detail in the aforementioned copending application Serial No. 772,459 (M-8485), portion 117 of the- print head assembly is adapted to house the print wires extending from the solenoid assemblies and to guide each of them along a curved path so as to cause the tips of the print wires W to be merged along a vertical straight line and maintained in this fashion within a jewel bearing member 119 provided at the nose N of the print head, as can best be seen in Figure lc . The body portion 117 of the print head 13 is joined to mounting disc 70 by means of fastening members 121.
Turning to a consideration of Figures Id and 4f it can be seen that the projection 19 whose opening 19a is adapted to receive the lower carriage guide shaft 15 and rack 16 is provided with a downwardly extending projection 19b which projection cooperates with a Hall effect actuator 120, shown best in Figures 7a and 7b. The Hall effect actuator 120 is provided with an elongated resilient arm 120a formed of a suitable metallic material and having a portion 121a which is bent inwardly from the bottom left-hand end of lead 121 to form a horizontally aligned mounting portion with three downwardly extending projections 121b, 121c and I2ld which are adapted to extend into and be secured to the mounting base (not shown) of the printer so as to secure the left-hand end of leaf spring element 121 in a fixed position. The opposite free end is
bent to form a short flange 121e positioned immediately adjacent to a Hall effect sensor 124. Leaf element 121 is provided with an upwardly extending tab 121f which - is positioned so as to be -engaged by downwardly extending projection 19b as the carriage assembly moves to the left end of the printer and approaches the left-hand margin of the print receiving medium (not shown) . As the print head moves in the direction shown by arrow 126 of Figure 7a, projection 19b engages tab'121f urging the leaf portion 121 from the solid line position to the dotted line position 121' so as to move flange 121e and permanent magnet 125 away from the Hall effect sensor 124. The permanent magnet member 125 is secured to flange I2le by a suitable epoxy. The movement of the permanent magnet member 125 causes Hall effect sensor element 124 to develop an electrical signal indicative of the fact that the print head has moved to the left-hand margin, which is typically caused by the performance of a carriage return operation.
The carriage assembly is usually brought to a halt in this position and is thereafter restarted to print the next line, typically after completion of the line feed operation. Presuming the carriage assembly 11 begins to move in the direction shown by arrow 127 of Figure 7a to print the next line, the resilient leaf arm 121 moves from the dotted line position 121' to its solid line position, returning the flange 121e and permanent magnet 125 to the solid line position causing the Hall effect sensor element 124 to generate a reverse type signal, i.e. a signal of reversed polarity which is utilized by the printer logic, for example, to enable the timing signals developed by Hall effect sensor 42 (see Figure If) to control printing and thereby assure the proper registry of the dot column patterns created on the print receiving medium.
Figure 8 shows the flat flexible printed circuit cable 43 laid out flat, i.e. before being mounted upon the print head assembly. The left-hand end of the flexible printed circuit cable has a substantially L-shaped thin metallic member 141 partially embedded within the insulating material 142, the exposed portion thereof having an elongated slot 141a. A plurality of thin printed circuit leads 144-150 are likewise embedded within the thin flexible insulating material 142 and one free end of each said leads extends beyond the lower edge 142a of the thin plastic material 142 to form bear exposed joining terminals 144a-l50a adapted to be electrically connected to, and preferably soldered to the end terminals of the solenoid windings. The opposite ends of the conductive leads 144-150 are connected to electrical terminals arranged along one array 66a of the socket type connector 66 (note also Figure Id) .
Another metallic insert 151 of substantially tri¬ angular shape is embedded within the plastic sheet 142 and serves to impart rigidity to the structure, as will be more fully described. Still another metallic sheet 153 of rectangular shape is embedded within the plastic material 142 along the lower edge 142a thereof and is provided with a brake at 153a to facilitate bending of the metallic insert 153. The right-hand portion has an elongated tab
153b extending downwardly from the right-hand portion 153c of metallic insert 153 and is designed to be bent in order to embrace two adjacent halves of the flat printed circuit cable as will be more fully described. The flat printed circuit cable member extending to the right-hand side of socket-type connector 66 divides into three sections 155, 156 and 157. Elongated section 157 is provided with three elongated conductors 158, 159 and 160 whose left-hand ends are connected to selected terminals of the right-hand array of contact 66b of
socket-type connector 60 while the opposite ends of the elongated conductors embedded within the thin insulating material 142 terminate in three exposed terminals 158a, 159a and 160a, respectively, said terminals being adapted for connection to Hall effect sensor 42 shown in Figures le and If.
The middle section 156 is provided with connector leads 162-165 terminating in exposed connector terminals I62a-165a. The left-hand ends of flexible conductors 166 and 167 are connected to selected ones of the terminals in the right-hand array 66b of socket-type connector 66. The ' opposite ends of flexible leads 166 and 167 terminate in exposed terminals 55 and 56 as shown in Figure lc , which terminals are adapted for electrically connecting the opposite polarity terminals of motor M.
The intermediate section 156 is further provided with a metallic insert 169 substantially embedded within the thin insulating sheet 142 and having an outwardly extending projection 169a. The manner in which the flexible printed circuit cable is utilized is as follows:
The flat printed circuit cable is arranged so that it substantially .encircles the portion of the print head in which the solenoid assemblies are arranged. The -thin rectangular shape metallic insert 170, which is provided with a pair of tabs 170a and 170b extending beyond edge 142b of central section 156 is positioned so that the tabs 170a and 170b are arranged about the opposite sides of the magnetic core member of one of the solenoid assemblies. The tabs are then bent inwardly so as to embrace the edges of the core member C of a solenoid assembly embraced between the solenoid mounting disc 70 and parasol 44 shown in Figure 8a. Thereafter, the tabs 170a and 170b are bent inwardly along dotted lines 170c and I70d in order to embrace the magnetic core member C of one of the solenoid
assemblies. This now positively locates section 156 of the flat flexible circuit cable. The cable is further bent along dotted lines 172, 173 and 174 so as to assume the configuration shown in. Figure 8b and also shown in Figure Id. The thin bendable elongated tab 153b is bent about the folded over portions 43h and 43k of the flexible printed circuit cable in the immediate region of bends 172 and 174 so as to retain the flat flexible printed circuit cable in the configuration shown in Figure 8b. The embedded metallic member 153 is adapted to be bend in half along dotted line 174 and is provided with a narrow elongated slot 153d colinear with imaginary line 174 to facilitate accurate location of this bend. The triangular-shaped element 151 serves as a stiffening member to impart stiffness to the region just to the right of the bent tab 153b whose marginal end portion 153b' can be seen to be bent downwardly over the recess 142g provided along the upper edge of 142f of the flat flexible printed circuit cable 43. Thereafter, the flexible printed circuit cable is maintained in the position embracing the solenoid assemblies of the print head by positioning the exposed end 141b of metallic insert 141 immediately adjacent to the metallic insert 169 provided in intermediate section 156 and by inserting bendable tab 169 through elongated opening -141a in metallic insert 141 thereby serving to mechanically secure the flexible printed circuit cable to the print head. As was described hereinabove, the cable is further maintained in position by means of the rearwardly extending projections 62c, 64b and 64c shown, for example, in Figures la and Id which are arranged to neatly maintain the printed circuit cable as well as the leads L extending from the plug-type connector 67.
The manner of operation of the self-propelled assembly of the present invention is as follows:
Assuming that the carriage assembly 11 is at the left-hand margin of the printer, this condition is sensed by the Hall effect sensor element 124 shown in Figure 7a, due to the fact that leaf element 121 is in the dotted line position 121' , thereby causing the printer logic to apply DC voltage of a polarity causing motor M to rotate in a direction which causes the pinion gear 52b (see Figure Id) to rotate in a clockwise direction as shown by arrow 190. Pinion gear 190 meshes with teeth 16a of rack 16 causing the carriage assembly to move to the right as shown by arrow 191. The pulses developed by sensor 42 are used to control the location of each dot column. In one preferred embodiment, seven (7) dot columns collectively define one (1) character. A full line is comprised of eighty (80) characters. After a line or a portion of a line has been printed and it is desired to return the print head assembly to the left-han • margin, in readiness for printing the next line, the DC polarity applied to the terminals of motor M is reversed causing the motor output shaft to rotate in the reverse direction which, in turn, causes pinion gear 52 to rotate counterclockwise as shown by arrow 192 thereby causing the carriage assembly to move in the direction shown by arrow 193 so as to return the carriage assembly to the left-hand margin. This condition is detected by virtue of the fact that projection 19b engages tab 121f of Hall effect actuator leaf 121 causing free arm I21e to displace permanent magnet 125 from Hall effect sensor 124 causing sensor 124 to develop a signal to cause a DC voltage of reverse polarity to be applied to motor M when the next line of characters is to be printed.
As was mentioned hereinabove, the rotation of the output shaft of motor M is coupled through pinion gear 46 to a meshing gear 47a causing the rotor assembly 47
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carrying permanent magnet members 48a and 48b to rotate at the same time. The poles of the magnet members pass Hall effect sensor 42 causing pulses to be generated by the Hall effect sensor which serve as registration pulses for 5 precisely locating each position along the line of print at which a dot column pattern is printed. For example, in a printer capable of printing ten (10) characters per inch, each character being comprised of seven (7) dot columns, the spacing between center lines of adjacent dot columns is j _0 °f the order of 0.015 inches. The timing pulses are preferably generated at the rate of one (1) per milli¬ second and preferably have a pulse width of 0.5 milli¬ seconds. This is accomplished by- the adjustment of the rotational speed and size and number of the permanent 15 magnet members arranged about the rotor assembly 47 and adapted to be sensed by the Hall effect sensor 42. Accurate adjustment of the Hall effect sensor 42 relative to the periphery of the permanent magnet members is facilitated by the elongated opening 41b provided in sensor 0 mounting bracket 41 shown in Figure le. The motor typically rotates at approximately 3500 rp . In order to print fifty (50) characters per second, sufficient permanent magnet members are provided to generate ten (10) pulses per revolution of the rotor spur gear 47. One revolution is 5 equated to linear travel of the print head 13 over a distance of 0.10 inches to provide a separation distance of 0.01 inches between adjacent dot column patterns.
The design of the printer enables printing to occur in both forward and reverse directions, if desired, 0 since similar timing registration pulses will be generated regardless of the direction of rotation of the rotor assembly 47.
The Hall effect sensor 42 and permanent magnet members may be replaced by a photosensor and a cooperating 5 code pattern, or any other arrangement capable of
generating the necessary timing pulses responsive to the energization of motor M.
The motor M is of extemely small size and is light weight, thereby minimizing the mass and inertia of the carriage assembly. The light weight carriage assembly permits the use of a motor of significantly reduced power output.
The selection of the gear ratio between the meshing gear members assures that the registration pulses are accurately related to each increment of linear distance through which the carriage asembly moves to assure extremely accurate registration of the dot column patterns. Thus, the present invention provides a novel self-propelled carriage assembly which eliminates the need for complex, tedious and expensive motors, belts, pulleys, clutches, and the like employed in conventional apparatus . The carriage is formed of a high precision plastic material such as, for example, polycarbonate mixed with polytetrafluoroethylene . The head adapter is formed of a less expensive but sufficiently durable plastic material and all gear members are also preferably formed of plastic material providing an extremely light weight and yet rugged carriage assembly. Simple and yet accurate adjustment of the print head nose relative to the printer platen is provided for by a pair of head adjustment cam members which may be readily and easily adjusted to obtain the proper spacing between the nose of the print head and printer platen.
The design of the assembly is quite simplified in that the single pair of carriage guide shafts is utilized to accurately guide the carriage assembly along the printer platen and wherein one of said carriage guide shafts is provided with an elongated rack member which cooperates with a carriage mounted pinion gear to form a rack and pinion drive for positively and yet accurately driving the carriage by means of a light weight bidirectional carriage mounted motor.
Although the carriage assembly is advantageously adapted for use with a print head .of the dot matrix impact type, it may readily be adapted to employ any other type of print head of both the . impact and non-impact type. The dot matrix impact print head of the type employed for use with the carriage assembly is provided with a flexible printed circuit cable arrangement which includes its own mounting elements as an integral part of the flexible printed circuit cable and .thereby greatly facilitates manufacture and assembly of the print head.
A latitude of modification, change and substi¬ tution is intended in the foregoing disclosure and, in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly in a manner consistent with the spirit and scope of the invention herein.
Next Patent: WO/1980/002535