EP0073810A1 - Imprimante a matrice de points - Google Patents

Imprimante a matrice de points

Info

Publication number
EP0073810A1
EP0073810A1 EP19820901066 EP82901066A EP0073810A1 EP 0073810 A1 EP0073810 A1 EP 0073810A1 EP 19820901066 EP19820901066 EP 19820901066 EP 82901066 A EP82901066 A EP 82901066A EP 0073810 A1 EP0073810 A1 EP 0073810A1
Authority
EP
European Patent Office
Prior art keywords
print head
spring
oscillation
printer according
spring means
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.)
Withdrawn
Application number
EP19820901066
Other languages
German (de)
English (en)
Inventor
Peter Hubert Reitberger
Helmut Weber
Frank Giessner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NCR Voyix Corp
Original Assignee
NCR Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NCR Corp filed Critical NCR Corp
Publication of EP0073810A1 publication Critical patent/EP0073810A1/fr
Withdrawn legal-status Critical Current

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
    • B41J25/00—Actions or mechanisms not otherwise provided for
    • B41J25/001—Mechanisms for bodily moving print heads or carriages parallel to the paper surface
    • B41J25/006—Mechanisms for bodily moving print heads or carriages parallel to the paper surface for oscillating, e.g. page-width print heads provided with counter-balancing means or shock absorbers
    • 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
    • B41J19/00—Character- or line-spacing mechanisms
    • B41J19/18—Character-spacing or back-spacing mechanisms; Carriage return or release devices therefor
    • B41J19/20—Positive-feed character-spacing mechanisms

Definitions

  • This invention relates to a dot matrix printer and, in particular, to a driving mechanism for such a printer.
  • the most common types of printers have been the thermal printer and the ink jet printer.
  • the performance of a non-impact printer is compared with that of an impact printer, one of the problems in the non-impact machine has been the control of the printing operation.
  • the impact operation depends upon the movement of impact members such as wires or the like and which are typically moved by means of an electromechanical system which is believed to enable a more precise control of the impact members.
  • the print head structure may be a multiple-nozzle type with the nozzles aligned in a vertical line and supported on a print head carriage which is caused to be moved or driven in a horizontal direction for printing in line manner.
  • the printer structure may include a plurality of equally-spaced, horizontally aligned single nozzle print heads which are caused to be moved in back-and-forth manner to print successive lines of dots in making up the lines of characters.
  • a print head carriage may be connected with a pulley and cable arrangement and driven by a separate motor for causing transverse movement of the carriage during printing operations.
  • Another driving system utilizes a lead screw connected with the carriage and driven by a separate motor for back-and-forth movement of the carriage.
  • a disadvantage of the motor driven carriage is the high cost of both the equipment and its operation.
  • a carriage plate carrying a plurality of print heads is mounted on the free ends of the central legs of two comb-like leaf springs while the corresponding ends of two other legs are fixed to the frame of the printer.
  • the reciprocating motion of the carriage plate is performed by a crank drive.
  • the special structure and arrangement of the leaf springs bearing the carriage plate provides for parallel movement of the plate relative to the platen during the back-and-forth motion.
  • a disadvantage of this arrangement is that the crank drive still requires substantial amounts of energy for the printing operation, and that the printing operation is rather noisy.
  • a dot matrix printer including at least one print head having spring means operably connected therewith, and driving means for causing movement of said at least one print head in side to side direction relative to a record medium movable past said at least one print head so as to enable said at least one print head to print a line on said record medium, characterized in that said driving means is arranged to cause said spring means to oscillate at a frequency corresponding with the natural frequency of the assembly of said spring means and said at least one print head so as to bring about oscillating motion of said at least one print head in said side to side direction.
  • a dot matrix printer including a platen providing support for a record medium, and at least one print head for printing on said record medium, characterized by spring means operably connected with said platen, and driving means arranged to cause said spring means to oscillate at a frequency corresponding with the natural frequency of the assembly of said spring means and said platen so as to bring about oscillating motion of said platen in side to side direction relative to said at least one print head supported in a stationary manner.
  • Fig. 1 is a diagrammatic view of spring means for causing horizontal movement of a print head
  • Fig. 1A is a circuit diagram of a drive for the spring means
  • Fig. 2 is a diagrammatic view of a plurality of print heads on a support plate which is caused to be moved by spring means in a horizontal direction
  • Fig. 3 is a view similar to portions of Fig. 1 and including circuit means for compensating the damping of the oscillating system;
  • Figs. 4A and 4B show a timing diagram of the voltage and deflection relationship
  • Fig. 5 shows the current pulse through the drive circuit of Fig. 3;
  • Fig. 6 is a view of ratchet means rotatable by horizontal movement of the print head carriage
  • Fig. 7 is a view of drive means driven by the ratchet means of Fig. 6 for enabling vertical motion of the record media
  • Fig. 8 is a diagrammatic view of a modified arrangement of spring means for causing horizontal movement of a platen
  • Fig. 9 is a diagrammatic view showing the combination of horizontal oscillation of the print head and vertical movement of the record media
  • Fig. 10 is a view showing another arrangement of spring means for causing horizontal movement of the print head, having straight line guide means with horizontal oscillating coil spring elements;
  • Fig. 11 shows still another arrangement of such spring means with the use of bent leaf springs performing the function of guide or bearing means along with the function of an oscillating drive;
  • Figs. 12A, 12B and 12C are diagrammatic showings of different arrangements employing a leaf spring in providing the vertical oscillating mechanism for record media movement;
  • Fig. 13 shows a scanning arrangement for measuring the instantaneous speed of the oscillating print head
  • Fig. 14 is a diagrammatic view of a still further spring means arrangement showing a bent leaf spring drive mechanism and a nozzle bar driven in oscillating manner;
  • Fig. 15 shows the use of a linear motor along with spring means for driving a print head in horizontal oscillating manner;
  • Fig. 16 is a circuit diagram of the linear motor.
  • Fig. 1 is a diagrammatic view showing an ink jet print head 10 supported from the free end 12 of a leaf spring 14.
  • the other end 16 of the leaf spring is secured to a fixed frame member 18.
  • the print head 10 has a nozzle 20 for ejecting an ink droplet 22 therefrom in performing a printing operation.
  • An electrodynamic drive system 24 for initiating or setting the leaf spring 14 into oscillation or swinging movement includes a permanent magnet 26 operable with an armature 28 overlying a central core portion 30 of the magnet and wound with a drive coil 32.
  • the drive coil 32 is energized by pulses amplified by a power transistor 31, as illustrated in Fig. 1A.
  • the armature 28 has a coupling member 34 in the form of a rod fixed thereto at one end and secured at the other end to the leaf spring 14 near the center thereof.
  • the leaf spring 14 operates with a natural frequency wherein the ink jet print head 10 is swinging freely and no electrical power is required for acceleration and deceleration of the head 10. In this manner, the consumed electrical power is only that power which is converted into frictional work.
  • a pulse is applied once for each forth movement of the leaf spring 14 in its back and forth movement and with the pulse frequency being equal to the frequency of spring oscillation.
  • Fig. 2 illustrates a plurality of ink jet print heads 40 carried on a support member 42 which, in turn, is supported from the free ends of a pair of leaf springs 44 and 46. The other ends of the leaf springs 44, 46 are secured to a frame member 48.
  • the print heads 40 are positioned to print on paper 50 or like record media which is caused to be trained around a platen 52. The driving or transporting of the paper 50 in a vertical direction past the line of printing is performed by means to be described later.
  • a drive module 54 similar in form to the electrodynamic drive system 24 of Fig. 1, is used to set the leaf springs 44 and 46 into oscillation with a natural frequency through a coupling member 56. It can be readily seen that the printing width is increased by a factor corresponding to the number of ink jet print heads 40 mounted on the support member 42.
  • Fig. 3 is a feed-back circuit for compensating the damping of the mechanically oscillating system of Fig. 1 wherein the ink jet print head 10 is supported from the free end 12 of the leaf spring 14 secured at its other end to the frame member 18.
  • the armature 28 is secured to the leaf spring 14 by the coupling member 34 and includes the drive coil 32 wound on the armature and connected to ground potential.
  • the feed-back circuit includes an operational amplifier 60 having components wired for use as an integrator and connected in series with a power amplifier 62 which energizes the drive coil 32.
  • the operational amplifier 60 acts as an integrating element by reason of its feedback capacity to effect a phase shift by ninety degrees so that energy is supplied in phase to the drive coil 32 by the power amplifier 62.
  • a measuring or sensing winding 64 is disposed around the drive coil 32 and is connected at one end to the operational amplifier 60 with the other end thereof connected to ground potential.
  • the positive feed-back compensates the damping so that the mechanical spring system oscillates with its natural frequency.
  • the damping compensation is required to maintain the oscillation at a constant amplitude wherein the natural frequency of spring oscillation is determined by the characteristics of the spring, such as mass, material, dimensions and design.
  • Figs. 4A, 4B and 5 show a timing relationship between the pulsating electrical energization of the drive system 24 of Fig. 1 and the mechanical oscillation of the spring 14. The relationship of Figs. 4A and 4B is shown by the formula .
  • the induced voltage V is proportional to the s pee ⁇ of oscillation and the deflection D is shown in time relation for a range of positive or plus current pulse and for a range of negative or minus current pulse.
  • the pulses of Fig. 5 are initiated at predetermined times which are not precisely fixed so that, for certain times or instants during the forward oscillating phase, an electrical pulse must be applied wherein the movement of the free mass spring oscillator is sustained by the electrical energization. More particularly, the pulses are applied, as indicated in Figs. 4A and 5, immediately after the maximum amplitude at a frequency equalling the natural frequency of oscillation. Pulses of opposite polarity are applied wherein the polarity corresponds to the respective direction of movement. Generally, the drive system 24 is pulsed or energized once for each cycle of printing.
  • FIGs. 6 and 7 illustrate means for obtaining a vertical drive for the paper from the longitudinal movement of the ink jet print head, wherein a ratchet gear 70 is positioned adjacent the platen 52 around which the paper 50 is trained in a path past the line of printing.
  • An oscillating horizontal push rod 72 drives a feed rod 74 against the teeth of the ratchet gear 70 and operates with a ratchet pawl 76 secured to a frame member 78 and engaging with the teeth of the gear 70.
  • the ratchet gear 70 is carried on a shaft 75 along with a gear 77 which meshes with a gear 79 on the end of a worm gear 80 which, in turn, meshes with and drives a drive gear 82 for rotating the platen 52.
  • the stepping mechanism enables driving the paper 50 by using the horizontal drive motion of the ink jet print head drive means and thereby eliminates the use of an electric motor.
  • FIG. 8 shows an ink jet print head 86 supported in stationary manner from a member 88 for printing on the paper 50 trained around the platen 52.
  • the platen 52 is supported for rotation on a shaft 90 which is slidably journaled for axial movement in bearing blocks 92 and 94 and which has a small plate 96 secured at the right end thereof associated with the armature 28 and the drive coil 32.
  • a coil spring 98 is- placed on the shaft 90 between the plate 96 and the block 94. In this arrangement, the print head 86 is stationary and the platen 52 along with the paper 50 is caused to be moved by action of the spring 98 in a horizontal oscillating direction as shown by the arrow.
  • a single print head 40 is illustrated in Fig. 9 as being carried on the support member 42 and oscillating in the horizontal direction, as in the manner illustrated in Fig. 2.
  • the paper 50 around the platen 52 is caused to be regularly moved in incremental manner in a vertical direction.
  • the most advantageous operating point is at the resonance of the spring mass system.
  • Fig. 10 illustrates a straight line guide arrangement for an ink jet print head 100 supported from a shaft 102 slidably journaled in bearing blocks 104 and 106 on a frame member 108.
  • the shaft 102 has a small plate 110 secured at the left end and a small plate 112 secured at the right end thereof.
  • the plate 110 is drivingly associated with the armature 28 and the drive coil 32.
  • a coil spring 114 is placed on the shaft 102 between the plate 110 and the block 104 and a coil spring 116 is placed on the shaft between the plate 112 and the block 106 to provide horizontal oscillation of the print head 100.
  • a pair of print heads 120 and 122 similar to the previously mentioned print heads 10, 40 and 86, are carried on a support member 124 having plates 126 and 128 at the ends thereof.
  • a pair of bent or folded leaf springs 130 and 132 are operably connected with the plates 126 and 128 in a manner to provide guide means as well as horizontal oscillation of the print heads 120 and 122.
  • the plate 126 is connected to the armature 28, drive coil 32 assembly through a shaft or rod 131.
  • the outer leg or portion of each spring is fixed or secured to a support member, as 133 for spring 132. Figs .
  • FIG. 12A, 12B and 12C show different arrangements of using a leaf spring for the verticaloscillating mechanism employed in transporting or driving the paper.
  • the paper 50 is transported and trained around a stationary roller 134, a pair of movable rollers 136 and 138 and then around a stationary roller 140.
  • a leaf spring 142 is secured at one end and is connected with a member 144 coupling the movable rollers 136 and 138 to provide the vertical movement for the paper.
  • Fig. 12B has the paper 50 trained around a stationary roller 146, a movable roller 148 and then around a stationary roller 150.
  • a leaf spring 152 is secured at one end and is connected to the movable roller 148 for vertical movement thereof in relation to the print head 154.
  • Fig. 12C shows a leaf spring 156 secured at one end and connected to a movable roller 158 for vertical movement.
  • a pair of guide members 160 and 162 are provided to be slidable or displaceable along a horizontal path to and from the roller 158 so as to allow changing the natural frequency of the spring 156.
  • Fig. 13 shows the armature 28, as illustrated in Figs. 1 and 3, with the drive coil or operating winding 32 and with the addition of the sensor winding 64 which is within the magnetic field in similar manner as is shown in Fig. 3.
  • the sensor winding is used for ascertaining the instantaneous speed of the oscillating ink jet print head.
  • the natural frequency of the spring mass oscillating system is very stable so that no accurate determination of the position of the ink droplets is required. It is only necessary that once for each oscillating p-eriod a simple synchronization of the ink jet with the mechanical movement should be performed.
  • This synchronization can be performed by the use of known position detectors, such as by optical scanning of the locating marks by capacitive measurement of an air gap wherein the capacitance is changed, or by the magnetic detection of the alteration of the magnetic flux.
  • An electrodyn.amic scanning arrangement for such synchronization in the present invention is provided by use of the sensor winding shown in Fig. 13 as a measuring element for the speed of movement of the print head.
  • the voltage having a magnitude which is proportional to the speed of the plunger or armature, is induced in the second or sensor winding 64 as a result of the movement. Since a fixed phase relationship exists between the displacement and the speed of movement for a sine-shaped wave movement, a synchronizing signal may be derived from the speed measuring signal by means of a zero voltage detector and this synchronizing signal can be applied to an associated electronic control unit.
  • Fig. 14 illustrates the use of a nozzle bar 166 having a plurality of ink jet nozzles 168 and carried on a support member 170 which has end plates 172 and 174 operably connected with bent or folded leaf springs 176 and 178.
  • the spring 176 is fixed or secured at the left side and the spring 178 is fixed or secured at the right side.
  • the spring 176 has an aperture 181 through which a coupling member 180 is movable and having one end secured to the end plate 172 and being connected at the other end to the oscillating assembly or electrodynamic drive system 24, similar to the unit shown in Fig. 1.
  • the width of an area to be printed is generally defined by the amplitude of the oscillation in connection with the number of ink nozzles so that it is possible to reduce the oscillating amplitude by increasing the number of nozzles.
  • the limiting case is to provide as many ink nozzles as there are ink spots or dots required to print one line on the paper, thus making a horizontal drive not required or necessary in such case.
  • Another arrangement is to provide as many nozzles as there are characters to be printed on a line with one nozzle assigned only for the width of each character so that the horizontal oscillation does not cover the spaces between the characters. A smaller amplitude of oscillation along with the same oscillation frequency results in a lower acceleration which is favorable for longer life of the print head. Figs.
  • Fig. 15 and 16 illustrate an arrangement wherein the amplitude of the horizontal drive is increased or is larger as a result of the decreased number of nozzles, as may be the case in a cost reduction scheme for the ink jet print heads. If the amplitude of the oscillation exceeds 2 centimeters, it is reasonable to use a magnet distributed over the entire length of oscillation and a meander-shaped coil arranged on a circuit board.
  • Fig. 15 shows a nozzle bar 182 having three ink nozzles 184 spaced at a distance apart and carried on the shaft 102 which is slidably journaled in bearing blocks 104 and 106 on the frame member 108, all in the manner as previously shown in Fig. 10.
  • Shaft 102 has the small plates 110 and 112 secured at the ends thereof along with the coil springs 114 and 116 to provide horizontal oscillation.
  • the magnet and coil arrangement of Fig. 15 is known in the art as a linear motor and limitations in the amplitude of the horizontal oscillation for this type of drive are not an important concern.
  • the linear motor 186 is diagrammatically shown with a magnetic field 188 and current flow to the line 190.
  • Fig. 16 shows the linear motor 186 in more detailed form with the magnetic field 188 along with current flow in the several lines 190.
  • the horizontal drive is in the direction of the arrow.
  • the drive or the energization can be realized by the above described electrodynamic principle and also by means of a simple electromagnet. This type of drive requires a strokelike energization in the proper time relationship with respect to the mechanical oscillation.
  • the amplitude of the oscillation of the horizontal oscillation is large, it may be possible that the oscillation of the vertical drive alone or by itself is insufficient to achieve a satisfactory print quality. In this case it may be useful to perform the vertical oscillation along the width of the paper in a dephased manner or where the vertical oscillation is combined with the feed movement of the paper.
  • the electromagnetic exitation of two vertical oscillators is in phase opposition wherein the vertical movement at one side of the paper is downward and the vertical movement at the other side of the paper is upward. A tilting oscillation of the paper feeding is accomplished which in combination with the horizontal oscillation produces a satisfactory print pattern.

Landscapes

  • Character Spaces And Line Spaces In Printers (AREA)

Abstract

Imprimante a matrice de points comprenant au moins une tete imprimante (40) et des organes d'entrainement (54) provoquant le deplacement de la tete d'impression dans une direction allant d'un cote a l'autre par rapport a un support d'enregistrement (50) defilant devant la tete d'impression de maniere a permettre a celle-ci d'imprimer une ligne sur le support d'enregistrement. Les systemes d'entrainement de l'art anterieur utilises pour deplacer une tete d'impression d'un cote a l'autre demandaient une energie considerable. Dans la presente invention, le systeme d'entrainement comprend un organe a ressort (44, 46) relie a la tete d'impression ainsi qu'un organe d'entrainement electro-dynamique (54) provoquant l'oscillation de l'organe a ressort selon une frequence correspondant a la frequence naturelle de l'ensemble constitue par l'organe a ressort et la tete imprimante, de maniere a provoquer un mouvement d'oscillation de la tete imprimante se deplacant d'un cote a l'autre. Cet agencement permet de reduire de facon notable l'energie requise pour l'acceleration et le freinage de la tete d'impression.
EP19820901066 1981-03-09 1982-02-19 Imprimante a matrice de points Withdrawn EP0073810A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US24199881A 1981-03-09 1981-03-09
US241998 1981-03-09

Publications (1)

Publication Number Publication Date
EP0073810A1 true EP0073810A1 (fr) 1983-03-16

Family

ID=22913065

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820901066 Withdrawn EP0073810A1 (fr) 1981-03-09 1982-02-19 Imprimante a matrice de points

Country Status (4)

Country Link
EP (1) EP0073810A1 (fr)
JP (1) JPS58500243A (fr)
CA (1) CA1192083A (fr)
WO (1) WO1982003123A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0109329A3 (fr) * 1982-11-03 1986-06-11 GENICOM Corporation Mécanisme d'entraínement équilibré pour tête d'impression
IT1187967B (it) * 1986-03-10 1987-12-23 Olivetti & Co Spa Aparecchio per la riproduzione digitale a colori di documenti
JPH0614567A (ja) * 1992-06-29 1994-01-21 Canon Inc 振動式リニア駆動装置及び該リニア駆動装置を有するプリンタ装置

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH375027A (fr) * 1961-04-14 1964-02-15 Paillard Sa Procédé d'ècriture et machine pour la mise en oeuvre de ce procédé
FR2085784B2 (fr) * 1970-04-02 1973-01-12 Hertz Carl

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8203123A1 *

Also Published As

Publication number Publication date
WO1982003123A1 (fr) 1982-09-16
JPS58500243A (ja) 1983-02-17
CA1192083A (fr) 1985-08-20

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Effective date: 19830518

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Inventor name: REITBERGER, PETER HUBERT

Inventor name: WEBER, HELMUT

Inventor name: GIESSNER, FRANK