High-speed Driving Device For Printer Or The Like

Abstract

A high-speed driving device for use in a high-speed printer or the like. The printer has actuatable printing elements each actuated from a rest position to a printing position. The high-speed driving device actuates each printing element with a plurality of actuators each comprising an electromagnetic system having a driving or operating electrical coil receptive of current pulses for developing opposite polarities in its core in conjunction with pole pieces forming a magnetic field for rocking to an operative position and to an inoperative rest position the core having a pole varied thereon and extending into a gap between the pole pieces. The core is constructed with a multiplicity of extensions or lever arms, one of which is normal to the core portion within the coil and engages a corresponding actuatable element to actuate it to its operative position when the core is rocked. The core is restored to its rest position by application to the operating coil of current of opposite polarity to the current actuating it to its operative position. A spring restores each actuatable printing element to its rest position in readiness for a next printing step. Each core is rockably mounted in a carriage for travel relative the actuation elements so that high-speed printing can be carried out.

Description

BACKGROUND OF THE INVENTION

The present invention relates to high-speed printers and more particularly to a high-speed driving device for printers and the like.

In known high-speed driving devices for actuating printing elements in a high-speed printer, the driving device is provided with a solenoid electromagnet that is energized for actuating the printing elements of the printer. The use of the known type of solenoid electromagnets presents a serious problem with respect to attaining high-speed in these apparatus in that friction occurs between the core and the yoke or mount for the core along the axial path of travel of the core during its movement and actuation. Furthermore, it is difficult to prevent mechanical oscillation because the core is generally restored or returned by a return spring which inherently introduces mechanical oscillations into the system. Accordingly, the response of the core to applied electrical signals applied to the operating coil is generally unsteady and the life of the driving device is reduced by this type of solenoid construction.

SUMMARY OF THE INVENTION

It is a principal object of the invention to provide a high-speed electromagnetic driving device for use in a printer suitable for high speed and stable operation.

Another object of the present invention is to provide a high-speed driving device that eliminates the disadvantages of the known high-speed printing driving devices.

A high-speed driving device according to the invention comprises a plurality of actuators carried on a carriage for actuating actuatable printing elements. Each actuator has an electromagnetic structure having an electrical coil receptive of current pulses from a control circuit for electromagnetically rocking a rockable magnetic core in the coil to an operative position and back to its rest position. Each core is provided with a multiplicity of arms, one of which functions as the actuating portion of the core that actuates the individual printing elements. A pair of plate pole pieces provide a magnetic field that coacts with each coil and core and for effecting its actuation.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the high-speed driving device will appear from the following description of an example of the invention, the novel features pointed out in the appended claims and attached drawings in which:

FIG. 1 is a plan view of a high-speed printer embodying the present invention;

FIG. 2 is a section view taken along section line II--II in FIG. 1;

FIG. 3 is a circuit diagram of control circuitry for the high-speed driving device and printer according to the invention; and

FIG. 4 is a fragmentary section view of a second embodiment of a part of the high-speed driving device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the invention, a carriage 1 of a wire-drive type printer is supported on a base 2 and is driven or moved in opposite directions axially of the worm gear 3. The carriage carries a plurality of actuators comprising a plurality of electromagnetic systems. Each actuator has magnetic field-forming means which comprise plate pole pieces 5, 5a and a permanent magnet 4. These are common to each actuator. The pole pieces 5, 5a define an elongated air gap between two spacers 6, 6a made of non-magnetic material intermediate a north pole N and a south pole S of the pole pieces, as illustrated.

A shaft 7 rockably mounts actuator elements or levers each comprising two lever arms. A first lever arm 8 functions as a coil core, and a second lever arm 9 normal thereto which functions to carrying out the actuating function later described. Each actuator has a bobbin 10 supported in a support 11 and a coil 12 wound on the bobbin for actuating rockably the rockable core 8 as later described. Each core 8 is provided with an end portion at a free end thereof which forms a pole, for example a pole N, and is free to be rocked from a rest position shown to rock the actuating or second lever arm 9 to an actuating position to be described. The core 8 has clearance within the bobbin to carry out this rocking movement.

The spacers 6, 6a are made of non-magnetic material and prevent the individual cores from banging up against the pole pieces 5, 5a which would result in decreasing the high-speed response of the apparatus. Those skilled in the art will recognize that instead of the spacers, appropriate stops may be provided to limit the movement of the cores to maintain the mode of operation desired.

In a printing press of the present type, five electromagnetic assemblies or structures as illustrated on the lefthand side position of the apparatus in FIG. 2, are provided on the left side and four on the right side disposed for actuating of the printing elements as the carriage travels axially of the worm gear 3 for carrying out printing operations as hereinafter described. The apparatus thus has two sets of elongated pole pieces, as shown in FIG. 2, and nine coils 12 and corresponding coil cores 8. The placing of the coils and cores on opposite sides of the axis of the support shaft 7 permits construction of a more compact carriage.

The upper end portions of each driving lever or arm 9 protrudes upwardly from the casing above the carriage through a longitudinal slot, as shown in FIG. 1, and will actuate a series of wires 16 connected to individual pins 17. The pins 17 are supported by pin-supporting plates 18, 19 and are biased toward the right into engagement with individual driving lever arms 9 by biasing or restoration springs 20. The actuation wires 16 are slidably supported by arcuate wire plates 21, 22 and extend through a wire guide block 23. The distal end of the individual wires is disposed adjacent a printing platen 14. The wires are used for executing printing of dots on a paper 24 in conjunction with a printing or inking ribbon 25 interposed between the platen 14 and the individual wires 16. In the present invention, nine wires are provided and their distal ends or tips are arranged vertically in a row facing the platen 14. Of course, other types of printing elements may be provided other than wire to be actuated by the actuators of the high-speed driving devices as will be seen.

In order to drive the actuator's driving lever arms 9, current pulses flowing in opposite directions are applied to the individual coils 12 for magnetizing the individual cores 8 in opposite polarities. When current is applied to form a north pole N, as illustrated in FIG. 2, the core will be attracted downwardly by the pole of the pole piece of opposite polarity and simultaneously repelled by the upper pole piece pole N, so that the driving lever 9 engages a corresponding pin 17 and drives it toward the left. When a current of opposite polarity flows through the operating coil 12 the core is magnetized so that a pole of opposite polarity is formed thereon and the core will be restored to its rest position at a high speed mode of operation. Thus when the individual cores are actuated to their operative position and drive the corresonding actuator lever arm to its driving position, the individual wires will carry out a printing operation and subsequent to the printing the energizing of the individual coils in an opposite polarity will restore the cores to their rest position.

The control of the individual cores is carried out by a corresponding control driving circuit, of the type illustrated in FIG. 3, for controlling the application of current pulses to the individual coils controlling the corresponding cores. The circuit for controlling one of the cores is illustrated and the control circuits for the other cores may be constructed accordingly.

The individual control or driving circuits each comprise a symmetrical circuit configuration in which inputs for controlling the desired core are applied to its corresponding control circuit across input terminals 26, 27, one of which is grounded and the other in series with a resistance R.sub.1 connected to the base of a transistor Tr.sub.1 connected through its emitter to a second transistor Tr.sub.2 as illustrated. The second transistor has its base grounded and its collector is connected to a junction to which a resistor R.sub.2 is connected which is connected to a power source E. A third transistor Tr.sub.3 has its emitter connected to the power source E, its base connected to a resistor R.sub.3 in series with a diode D.sub.1 and both are connected to the collector of the second transistor. A diode D.sub.3 is connected to collector of the third transistor and the power source. A symmetrical configuration is provided as illustrated.

In a subcircuit having a symmetrical configuration with that described has second input terminals 29, 30. One terminal is in series with a base resistor R.sub.6 connected to the base of a first transistor Tr.sub.6 is connected to a second transistor Tr.sub.5 having its collector connected to a junction to which a resistor R.sub.5, a diode D.sub.2 and base resistor R.sub.4, connected to the base of a third transistor Tr.sub.4, are connected. A diode D.sub.4 is connected similarly to the diode D.sub.3 in the subcircuit first described. A load L corresponding to one of the operating coils is connected to both symmetrical circuits.

When a positive current pulse P.sub.1 is applied between the input terminals 26, 27, the first transistor Tr.sub.1 is rendered conductive and electric current flow from a power source connected at the terminal E through the emitter-base connection of the third transistor Tr.sub.3 and its base resistor R.sub.3 and the series diode D.sub.1 and connector-emitter of the second transistor Tr.sub.2. Therefore, the third transistor Tr.sub.3 is rendered conductive and electric current flows in the load L, corresponding to the coils 12, in the direction of the arrow 28.

When a positive pulse P.sub.2 is applied between the second set of input terminals 29, 30, the transistor Tr.sub.5 is rendered conductive and electric current flows in the direction shown by an arrow 31. In this manner, electric current flows alternately in opposite directions in the load L by virtue of two series pulses applied alternately to the two sets of input terminals. When the second pulse is applied, the core 8 is returned to its rest position as before described.

A second embodiment of a high-speed electromagnetic driving device according to the invention is illustrated fragmentarily in FIG. 4. In this embodiment, a permanent magnet 32 is mounted between elongated plate pole pieces 33, 33a similarly to the first-described embodiment. A pivot shaft 34 is mounted centrally of a carriage assembly designated generally as 35. A plurality of cores in actuators, such as a core 36, made of magnetic material and each having a related driving lever arm 37 upstanding thereto are rockably supported as before described. A supplementary lever arm 38 is provided on each actuator and is made of the same material as the core lever arm 36 and functions to form a closed magnetic path in conjunction with the pole pieces 33, 33a to minimize the magnetic resistance or reluctance. The free end portion of each supplementary lever arm has a pole thereon of opposite polarity than that of the pole piece to which it is adjacent. A bobbin 39 supports a coil 40 for each actuator similarly to the embodiment described before. In this construction, the core 36 and the supplementary lever arm 38 are attracted to the magnetic field-forming pole pieces 33, 33a so that the driving power of the driving lever 37 is increased when pulses are applied to the operating coil 40 in the manner heretofore described and the individual cores are restored as before described. While the high-speed driving device has been described as applicable to high-speed printers, those skilled in the art will readily understand the device is applicable to punching apparatus and the like.

Claims

What we claim and desire to secure by letters patent is:

1. A high-speed driving device for high-speed printers and the like comprising, means forming a flux path having opposite polarity poles and an air gap therebetween, a rockable lever rockably mounted having a first lever arm made of magnetic material extending into said air gap and a second lever arm at an angle relative to the first lever arm and actuated thereby from a rest position to an operative position for impacting an actuatable element and restored to said rest position, means to actuate said first lever arm thereby to actuate said second lever arm comprising an operating coil stationary relative to said rockable lever for varying said first lever arm fro one polarity to another to effect attraction alternately by said poles of opposite polarity to rock said rockable lever from a rest position to an operative position and restore it to a rest position thereof, means rockably mounting said rockable lever, means to apply current pulses serially to said operating coil to effect said rocking, means to apply said current pulses to said operating coil, an actuatable element disposed freely movable independently of said second lever arm and normally biased to a rest position in which said second lever arm impacts it to actuate said actuatable element, and means biasing the actuatable element to said rest position thereof.

2. A high-speed driving device for high-speed printers and the like according to claim 1, in which first lever arm comprises a core in said operating coil.

3. A high-speed driving device for high-speed printers and the like according to claim 2, including a travelling carriage mounting said lever and said coil for moving them selectively to a plurality of discrete positions, and means to move the carriage.

4. A high-speed driving device for high-speed printers and the like comprising, means defining a magnetic circuit having two poles of opposite polarity and an air gap therebetween, a plurality of actuators comprising rockable levers each having a first lever arm made of magnetic material extending into said air gap, each rockable lever having a second lever arm at an angle relative to the first lever arm, means for said actuators to actuate said rockable levers comprising operating coils corresponding in number to the number of rockable levers and stationary relative to said rockable levers, each operating coil having said first lever arm of a corresponding rockable lever extending therethrough as a core, means to apply series current pulses to the operating coils to vary the magnetic polarity of the individual cores to different polarities for repulsion and attraction by the two poles between which each is disposed for actuation from a rest position to an operative position and restoring thereof to said rest position, means to apply said current pulses to said coils, whereby said second lever arm is rocked from a rest position to an operative position for impacting a member operable thereby, a plurality of actuatable elements disposed freely movable independently of said actuators, said actuatable elements corresponding in number to the individual second lever arms of said rockable levers, means biasing the actuatable elements individually to a respective rest position at which said actuatable elements are impacted individually by a corresponding second lever arm.

5. A high-speed driving device for high-speed printers and the like according to claim 4, in which said means defining said flux path comprises a pair of elongated pole pieces defining said air gap as an elongated air gap, each of the first lever arms being disposed sequentially in said air gap.

6. A high-speed driving device for high-speed printers and the like according to claim 5, in which each of said rockable levers comprises a third lever arm made of magnetic material extending toward said pole pieces and having a polarity opposite to a pole piece next to which it is adjacent thereby to magnify the impacting of said second lever arm.

7. A high-speed printer comprising, a plurality of actuatable printing devices freely movable independently and operable from a rest position to an operative position for effecting printing, a plurality of actuators for impacting the actuatable printing devices individually for actuating them comprising, means defining pole pieces defining an air gap between two poles of opposite polarities, a plurality of rockable levers each having a lever arm of magnetic material extending into said air gap and a second lever arm at an angle relative to the first lever arm for impacting the printing devices, a plurality of operating coils stationary relative to the corresponding actuators and each having the first arm of a corresponding lever arm extending therethrough as a core, means for energizing the operating coils selectively for developing different polarities in the individual cores thereby to rock the rockable lever arms from a rest position to a position for impacting the printing devices and to return them to said rest position, and biasing means to restore the printing devices to a corresponding rest position after impaction thereof for printing and after the restoration of said rockable lever arms to said rest position thereof.

8. A high-speed printer according to claim 7, in which said second lever arm of each rockable lever is disposed vertically, a common shaft rockably mounting said rockable levers, travelling means mounting said rockable levers and said printing devices for travel jointly along a given path.

9. A high-speed printer according to claim 8, including a platen relative to which said travelling means travels.

10. A high-speed printer according to claim 7, in which said pole pieces comprises two elongated pole pieces, and in which said air gap is elongated.