EP0017014B1 - Wire printer with cutting device - Google Patents

Wire printer with cutting device Download PDF

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Publication number
EP0017014B1
EP0017014B1 EP80101205A EP80101205A EP0017014B1 EP 0017014 B1 EP0017014 B1 EP 0017014B1 EP 80101205 A EP80101205 A EP 80101205A EP 80101205 A EP80101205 A EP 80101205A EP 0017014 B1 EP0017014 B1 EP 0017014B1
Authority
EP
European Patent Office
Prior art keywords
roller
needle head
knife
cam
needle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80101205A
Other languages
German (de)
French (fr)
Other versions
EP0017014A1 (en
Inventor
Fritz Siegenthaler
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.)
Ascom Autelca AG
Autelca AG
Original Assignee
Ascom Autelca AG
Autelca AG
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 Ascom Autelca AG, Autelca AG filed Critical Ascom Autelca AG
Publication of EP0017014A1 publication Critical patent/EP0017014A1/en
Application granted granted Critical
Publication of EP0017014B1 publication Critical patent/EP0017014B1/en
Expired legal-status Critical Current

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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
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/66—Applications of cutting devices
    • B41J11/70—Applications of cutting devices cutting perpendicular to the direction of paper feed
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8821—With simple rectilinear reciprocating motion only
    • Y10T83/8841—Tool driver movable relative to tool support

Definitions

  • the invention relates to a dot matrix printer of the type specified in the preamble of claim 1.
  • a needle printer of this type known from FR-A-2 373 397 has a knife roller, which consists of a circular knife with a coaxial, roller-forming attachment and is movably arranged on the needle head in a rest position and in a working position.
  • the knife roller is moved into its working position by its own, multi-part actuating device on the needle head, in which the roller is pressed against the recording medium and the circular knife against the surface of the counter knife perpendicular to the recording medium, and the needle head is moved in as for printing Row direction shifted.
  • the roll rolls on the record carrier and rotates the circular knife sliding on the counter knife surface.
  • the knife roller is mounted on the free end of an arm of a two-armed lever which is pivotable about an axis parallel to the axis of the knife roller and is displaceable in the direction of this axis and is loaded in its pivoting direction by a first spring and in the direction of displacement by a second spring Press the knife roller into the working position on the record carrier and on the counter knife surface.
  • a first roller is arranged at the end of the path covered by one end of the lever axis during the needle head displacement so that it is the axis of the Lever moves against the action of the second spring when the end of the axis runs on this roller, and at the end of the path that the knife roller moves during this needle head displacement, a second roller is arranged so that it over the knife roller against the action of the first spring the record carrier level lifts when the knife roll runs on this second roll.
  • the lever In this rest position, the lever is held by a spring-loaded pawl, which interacts with the other arm of the two-armed lever both in its pivoting direction and in its direction of displacement and is likewise mounted on the needle head and can be triggered by an electromagnet attached to the needle head. If the electromagnet is excited while the first roller holds the lever axis in its position displaced against the action of the second spring and the second roller holds the roller knife in its position raised against the action of the first spring, the springs move the lever with the roller knife into the working position when the needle head is moved back.
  • the mechanism driven by moving the needle head consisting of parts carried by the needle head (in addition to the pivoting axially displaceable lever, pawl, return springs, electromagnet) and stationary parts (rollers), by means of which the knife roller is moved from a rest position into a working position and vice versa , is structurally complex. It increases the weight to be guided by the needle head guide, which is necessary for an accurate printing process, and the inert mass to be driven by the displacement drive of the needle head, which should be accelerated and decelerated quickly for a high printing speed.
  • the sliding drive must not only perform the cutting work during the cutting process, but also the friction caused by pressing the knife roller against the recording medium in the needle head guide and for moving the knife roller from the rest position into the working position and vice versa, overcoming the force of the two springs, the needle head guide must support the needle head against the corresponding reaction forces, which increases the friction in the needle head guide.
  • the invention seeks to remedy this.
  • the invention as characterized in the claims, solves the problem of creating a needle printer with a cutting device which is structurally simpler and places less strain on both the needle head guide and the displacement drive for the needle head.
  • the advantages achieved by the invention are essentially to be seen in the fact that only the roller mounted on the needle head is used to drive the cutting device, and that the needle head is not actuated by a mechanism for the transition from the printing to the cutting process and vice versa, but is respectively pushed as far, that the roller is moved beyond the free end of the cam lever or up to this lever end.
  • the slope of the curve section on the lever can be chosen to be small, so that the knife blade is advanced with a force that is greater than the thrust force exerted on the roller by the displacement drive.
  • the dot matrix printer is characterized by an easily drivable cutting device of simple construction with low weight and correspondingly low susceptibility to failure and a long service life.
  • the needle head 1 is included Except for the roller 3 mounted on it on an angled axis 2 and belonging to the cutting device, shown in thinner lines than the other parts and only shown in outline in FIGS. 3 to 6.
  • the paper tape not shown, is guided from the supply roll, also not shown, through an insertion slot 4 and between two conveyor rollers 5, which are driven by a motor 6, onto a pressure bar 7, on which the stationary counter knife 8 of the cutting device is formed.
  • the needle head 1 is slidable at the top of a guide bar 11 and at the bottom by means of guide rollers 12 and 13 on a round bar 14, displaceably guided parallel to the direction of the lines to be printed.
  • the guide bar 11 and the round rod 14, like the pressure beam 7, are fastened at one end to the left side wall 15 in FIG. 1 and at the other end to a right intermediate wall 16.
  • the lower guide rollers 12 are profile rollers on axially fixedly connected to the needle head 1.
  • the axes of the upper guide rollers 13 are mounted on the fork-shaped slotted ends of a leaf spring 17 fastened in the middle to the needle head 1 and pressed against the round rod 14 with a spring force exceeding the force of gravity for the safe guidance of the needle head 1.
  • a cable drive serves to move the needle head 1.
  • the stretch-proof rope 18 shown in dash-dot lines runs from a rope end fastened to the side wall 15 over a circumferential half of a groove of a double-groove rope pulley 19 mounted on the needle head 1, a rope pulley 20 mounted on the side wall 15 and a rope pulley 21 mounted in a recess in the intermediate wall 16 to a traction sheave 22, which has a screw groove, is arranged between the intermediate wall 16 and a right side wall 23 and is driven by a reversible stepper motor 24.
  • the cable 18 continues over a cable pulley 25 arranged in a second recess in the intermediate wall 16 and over the other circumferential half of the other groove of the double-groove cable pulley 19 to the intermediate wall 16, to which the other cable end is fastened.
  • the needle head 1 When the motor 24 with the traction sheave 22 drives the cable 18 in the direction of the arrows shown in FIG. 1, the needle head 1 is moved in the line writing direction, i.e. i. 1 and 3 to 6 pulled from right to left, the double-groove pulley 19 rotating in the direction of the arrow shown in FIG. 1. If the cable 18 (after reversing the direction of rotation of the motor 24) is driven in the opposite direction, the direction of rotation of the double-groove pulley 19 also being reversed, the needle head 1 in FIGS. 1 and 3 to 6 is pulled from left to right.
  • the knife blade 27 shown in FIGS. 1 to 5 in its rest position and in FIG. 6 (in a position 27c) shortly before the end of its cutting stroke is slidably guided on the counter knife 8 and on the bar 9.
  • a pressure roller 28 on an axis 29 holds the knife blade 27 on the counter knife 8 and bar 9, a pin 30 and a roller 31 (FIG. 1) guide the knife blade 27 laterally.
  • the cutting edge 33 of the knife blade 27 runs at an obtuse angle V-shaped, symmetrically to the perpendicular bisection of the cutting edge 34 of the counter knife 8. Since the cutting edges 33 and 34 do not run parallel but at an acute angle to one another, cutting is carried out in two small places, so that a small feed force for the knife blade 27 is sufficient.
  • the symmetrical course of the cutting edge 33 has the effect that the reaction force during the cutting process acts in the opposite direction parallel to the feed direction of the knife blade 27, that is to say practically has no component which loads the lateral guide (pin 30, roller 31 and the pin 38 and roller 39 mentioned below) , so that no complex guidance is necessary and the sliding friction is nevertheless negligible.
  • the knife blade 27 is fixedly connected by a spacer 36 to a guide tab 37 which is slidably guided on the bar 11 by a bolt 38 which has a head which extends over the guide tab 37 and a roller 39.
  • the bolt 38 is fastened to a shoulder 40 of the strip 11 and the roller 39 is mounted.
  • the knife blade 27 forms a cam carrier for a curve consisting of three sections 41, 42, 43 of a flat thrust cam mechanism, the drive element of which is the roller 3.
  • the first curve section 41 runs on the back of the knife blade (knife blade back) at right angles to the direction of advance of the knife blade, i. H. parallel to the guide (11, 14) of the needle head 1 from a position which is assigned to the beginning of the lines to be printed, d. H. from the point at which the roller 3 is in the rest position of the needle head 1 shown in solid line in FIG. 1 to a little beyond the point at which the roller 3 is at the end of the lines at which the needle head and the roller 1 and 4 are designated by 1 and 3a.
  • the second cam section 42 extends essentially at an acute angle to the first cam section 41 and is formed on the side of a cam lever 44 facing away from it.
  • the cam lever 44 is pivotally mounted on the guide tab 37 about a pin 45 and rests with its free end under the action of a tension spring 46 at the location of the first cam section 41, at which the roller 3 is in its mentioned position 3a, with it is comparable to a switch tongue.
  • the distance between the pivotably mounted end of the cam lever 44 from the first cam section 41 is so large that the roller 3 runs between the first cam section 41 and the lever 44 (from right to left in FIG. 1, see FIG. 4) can.
  • the greatest distance of the second curve section 42 from the first 41 is equal to the stroke of the knife blade 27, which is slightly larger than the distance of the apex 47 from the ends of the obtuse-angled V-shaped cutting edge 33.
  • the third curve section 43 is formed on the edge of an arm 48 facing the first curve section 41, which is made in one piece with the knife blade 27.
  • the third curve section 43 starts from a semicircular arc at the beginning of the first curve section 41 and first runs briefly parallel at a distance from the first curve section 41 that does not exceed the diameter of the roller 3, as a result of which a niche 49 receiving the roller 3 in the rest position of the needle head 1 ( 1 and 4 to 6) is formed, then at an acute angle to the first cam section 41 and finally engages over the pivotably mounted end of the cam lever 44 at a distance which is slightly larger than the diameter of the roller 3.
  • the pin 45 is located above a point of the first curve section 41 which is at a smaller distance from its right start (recess 49) in FIG. 1 than from the left end of the first curve section 41 in this figure.
  • the curve inclination angle of the second curve section 42 is accordingly smaller than that of the third curve section 43.
  • Two tension springs 51 are attached at one end to the axis 29 of the pressure roller 28 and at the other end to the knife blade 27 and hold them non-positively with the first and second curve sections 41 and 42 on the roller 3, as in connection with the mode of operation of the dot matrix printer is explained in more detail.
  • the knife blade 27 has on both sides of the path on which the pressure roller 28 runs on it two trapezoidal cutouts 52 to reduce its mass so that a small accelerating force is sufficient for the advance of the knife blade 27 and vibrations exert only the lowest possible forces on the knife blade 27.
  • the roller 3 mounted on it In the rest position of the needle head 1, the roller 3 mounted on it is located in the recess 49 of the knife blade 27 (FIGS. 1 and 3).
  • the knife blade 27 is fixed in its rest position.
  • the needle head 1 runs from its rest position 1 to position 1a (FIGS. 1 and 4) and back.
  • the roller 3 runs to its position 3a and back on the first curve section 41.
  • the knife blade 27 stops.
  • the cam lever 44 is raised in the position 3a of the roller (position 44a) and returns to its rest position, while the roller 3 runs back on the curve section 41 from the position 3a to its rest position, in which it is designated by 3.
  • the needle head 1 after printing the last line is moved beyond position 1a to position 1b (FIGS. 1 and 5), in which the roll is in position 3b.
  • position 1b FIGS. 1 and 5
  • the needle head 1 is withdrawn from the position 1b into the rest position 1.
  • the roller runs from position 3b first on the second curve section 42, pushing the knife blade 27 downward.
  • FIG. 6 shows the needle head and the roller in the operating position 1 c or 3 c shortly before the end of the cutting stroke of the knife blade 27 c.
  • the roller 3 leaves the second curve section 42, and the knife blade 27 is returned to its rest position by the springs 51 and / or by the roller 3 running on the third curve section 43.
  • the springs 51 are not absolutely necessary because the third curve section 43 reliably brings the knife blade 27 back into its rest position.
  • the sliding friction of the guidance of the knife blade 27 and the guide tab 37 is sufficient if no shocks occur in order to keep the knife blade 27 in its rest position, when the needle head runs from its rest position 1 into its position 1a and back or into position 1b.
  • the tension of the springs 51 can be so small that it is negligible compared to the force required to overcome the resistance that occurs when cutting off.
  • a very small tension is also sufficient for the spring 46, so that the feed force of the roller 3 required to lift the cam lever 44 into its position 44a shown in FIGS. 1 and 4 is negligible.
  • the force with which the roller 3 running on the second curve section 42 has to be displaced in order to advance the knife blade 27 is, because of the inclination of the second curve section 42, much smaller than the resistance to be overcome by the knife blade 27 for the cutting process, and this is through the angled course of the cutting edge 33 of the knife blade 27 is kept small. Also negligible is the force which the roller 3 running on the third curve section 43 must exert to return the knife blade to its starting position, because this curve section 43 is also inclined; it is only necessary to overcome the sliding friction of the knife blade 27 and the flap 37, and if necessary the springs 51 help.
  • the power of the motor 24 for the knife blade drive is thus optimally utilized.
  • the reaction force acting on the needle head 1 during the cutting process does not increase its guide resistance because it is taken up by the guide rollers 12.
  • a drive motor 24 which is dimensioned in the usual way only for moving the needle head 1, is sufficient - as has been shown - for additionally driving the cutting device described. It should be borne in mind that this motor 24 must also be dimensioned in a fast-working dot matrix printer to overcome the inertia of the needle head at the beginning of its advancing and retracting movement, and that the roller 3 only after the beginning of the retracting movement of the needle head 1 on the inclined second one Curve section 42 runs, the motor 24 no longer having to accelerate the needle head and thus has reserve power to move the roller 3 during the cutting process.
  • the present dot matrix printer also does not require any special control device for the advancement and retraction of the knife blade 27.
  • This motor rotates a few steps further after the last line feed of the needle head 1, whereupon the knife blade 27 is pushed forward and withdrawn again when the needle head 1 is subsequently withdrawn.

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Description

Die Erfindung betrifft einen Nadeldrucker der im Oberbegriff des Anspruchs 1 angegebenen Art.The invention relates to a dot matrix printer of the type specified in the preamble of claim 1.

Ein aus der FR-A-2 373 397 bekannter Nadeldrucker dieser Art hat eine Messerrolle, die aus einem Kreismesser mit einem koaxialen, eine Rolle bildenden Ansatz besteht und am Nadelkopf in eine Ruhestellung und in eine Arbeitsstellung bewegbar angeordnet ist. Zum Abschneiden des Aufzeichnungsträgers wird die Messerrolle durch eine eigene, mehrteilige Betätigungseinrichtung am Nadelkopf in ihre Arbeitsstellung, in der die Rolle an den Aufzeichnungsträger und das Kreismesser an die zum Aufzeichnungsträger senkrechte Fläche des Gegenmessers gedrückt ist, bewegt, und der Nadelkopf wird wie zum Drucken in Zeilenrichtung verschoben. Dabei rollt die Rolle auf dem Aufzeichnungsträger und dreht das an der Gegenmesserfläche gleitende Kreismesser. Die Messerrolle ist hierzu am freien Ende eines Armes eines zweiarmigen Hebels gelagert, der um eine zur Messerrollenachse parallele Achse schwenkbar und in Richtung dieser Achse verschiebbar gelagert und in seiner Schwenkrichtung durch eine erste Feder sowie in der Verschieberichtung durch eine zweite Feder belastet ist, um die Messerrolle in Arbeitsstellung an den Aufzeichnungsträger und an die Gegenmesserfläche zu drücken. Um den Hebel mit der Messerrolle an einem Ende des Verschiebeweges des Nadelkopfes aus der Arbeitsstellung in die Ruhestellung zu bewegen, ist an dem Ende des Weges, den ein Ende der Hebelachse bei der Nadelkopfverschiebung zurücklegt, eine erste Rolle so angeordnet, daß sie die Achse des Hebels gegen die Wirkung der zweiten Feder verschiebt, wenn das Achsenende auf diese Rolle läuft, und an dem Ende des Weges, den die Messerrolle bei dieser Nadelkopfverschiebung zurücklegt, ist eine zweite Rolle so angeordnet, daß sie die Messerrolle gegen die Wirkung der ersten Feder über die Aufzeichnungsträgerebene hebt, wenn die Messerrolle auf diese zweite Rolle läuft. In dieser Ruhestellung wird der Hebel durch eine federbelastete Klinke gehalten, die mit dem anderen Arm des zweiarmigen Hebels sowohl in dessen Schwenkrichtung als auch in dessen Verschieberichtung zusammenwirkt und gleichfalls am Nadelkopf gelagert sowie durch einen am Nadelkopf befestigten Elektromagneten auslösbar ist. Wird der Elektromagnet erregt, während die erste Rolle die Hebelachse in ihrer gegen die Wirkung der zweiten Feder verschobenen Stellung und die zweite Rolle das Rollenmesser in seiner gegen die Wirkung der ersten Feder gehobenen Stellung hält, bewegen die Federn den Hebel mit dem Rollenmesser in die Arbeitslage, wenn der Nadelkopf zurück verschoben wird.A needle printer of this type known from FR-A-2 373 397 has a knife roller, which consists of a circular knife with a coaxial, roller-forming attachment and is movably arranged on the needle head in a rest position and in a working position. To cut the recording medium, the knife roller is moved into its working position by its own, multi-part actuating device on the needle head, in which the roller is pressed against the recording medium and the circular knife against the surface of the counter knife perpendicular to the recording medium, and the needle head is moved in as for printing Row direction shifted. The roll rolls on the record carrier and rotates the circular knife sliding on the counter knife surface. For this purpose, the knife roller is mounted on the free end of an arm of a two-armed lever which is pivotable about an axis parallel to the axis of the knife roller and is displaceable in the direction of this axis and is loaded in its pivoting direction by a first spring and in the direction of displacement by a second spring Press the knife roller into the working position on the record carrier and on the counter knife surface. In order to move the lever with the knife roller at one end of the displacement path of the needle head from the working position into the rest position, a first roller is arranged at the end of the path covered by one end of the lever axis during the needle head displacement so that it is the axis of the Lever moves against the action of the second spring when the end of the axis runs on this roller, and at the end of the path that the knife roller moves during this needle head displacement, a second roller is arranged so that it over the knife roller against the action of the first spring the record carrier level lifts when the knife roll runs on this second roll. In this rest position, the lever is held by a spring-loaded pawl, which interacts with the other arm of the two-armed lever both in its pivoting direction and in its direction of displacement and is likewise mounted on the needle head and can be triggered by an electromagnet attached to the needle head. If the electromagnet is excited while the first roller holds the lever axis in its position displaced against the action of the second spring and the second roller holds the roller knife in its position raised against the action of the first spring, the springs move the lever with the roller knife into the working position when the needle head is moved back.

Der durch Verschieben des Nadelkopfes angetriebene, aus vom Nadelkopf getragenen Teilen (zusätzlich zur Schwenkbarkeit axial verschiebbarer Hebel, Klinke, Rückholfedern, Elektromagnet) und ortsfesten Teilen (Rollen) bestehende Mechanismus, durch den die Messerrolle aus einer Ruhe- in eine Arbeitsstellung und umgekehrt bewegt wird, ist konstruktiv aufwendig. Er vergrößert das von der für einen genauen Druckvorgang notwendigerweise präzisen Nadelkopfführung zu führende Gewicht und die vom Verschiebeantrieb des Nadelkopfes anzutreibende träge Masse, die für eine hohe Druckgeschwindigkeit schnell beschleunigt und verzögert werden sollte. Der Verschiebeantrieb muß beim Abschneidevorgang nicht nur die Schneidarbeit leisten, sondern auch die durch das Andrücken der Messerrolle an den Aufzeichnungsträger in der Nadelkopfführung auftretende Reibung und zum Bewegen der Messerrolle aus der Ruhelage in die Arbeitslage und umgekehrt die Kraft der beiden Federn überwinden, wobei die Nadelkopfführung den Nadelkopf gegen die entsprechenden Reaktionskräfte abstützen muß, wodurch die Reibung in der Nadelkopfführung zunimmt.The mechanism driven by moving the needle head, consisting of parts carried by the needle head (in addition to the pivoting axially displaceable lever, pawl, return springs, electromagnet) and stationary parts (rollers), by means of which the knife roller is moved from a rest position into a working position and vice versa , is structurally complex. It increases the weight to be guided by the needle head guide, which is necessary for an accurate printing process, and the inert mass to be driven by the displacement drive of the needle head, which should be accelerated and decelerated quickly for a high printing speed. The sliding drive must not only perform the cutting work during the cutting process, but also the friction caused by pressing the knife roller against the recording medium in the needle head guide and for moving the knife roller from the rest position into the working position and vice versa, overcoming the force of the two springs, the needle head guide must support the needle head against the corresponding reaction forces, which increases the friction in the needle head guide.

Hier will die Erfindung Abhilfe schaffen. Die Erfindung, wie sie in den Ansprüchen gekennzeichnet ist, löst die Aufgabe, einen Nadeldrukker mit einer Abschneidevorrichtung zu schaffen, die konstruktiv einfacher ist und sowohl die Nadelkopfführung als auch den Verschiebeantrieb für den Nadelkopf weniger belastet.The invention seeks to remedy this. The invention, as characterized in the claims, solves the problem of creating a needle printer with a cutting device which is structurally simpler and places less strain on both the needle head guide and the displacement drive for the needle head.

Die durch die Erfindung erreichten Vorteile sind im wesentlichen darin zu sehen, daß zum Antrieb der Abschneidevorrichtung nur die am Nadelkopf gelagerte Rolle dient, und daß der Nadelkopf zum Übergang vom Druck- zum Abschneidevorgang und umgekehrt keinen Mechanismus betätigt, sondern jeweils so weit geschoben wird, daß die Rolle bis über das freie Ende des Kurvenhebels hinaus bzw. bis an dieses Hebelende bewegt wird. Dabei kann die Steigung des Kurvenabschnitts am Hebel klein gewählt werden, so daß die Messerklinge mit einer Kraft vorgeschoben wird, die größer als die vom Verschiebeantrieb auf die Rolle ausgeübte Schubkraft ist. Insgesamt zeichnet sich der Nadeldrucker durch eine leicht antreibbare Abschneidevorrichtung einfacher Konstruktion mit geringem Gewicht und entsprechend geringer Störanfälligkeit und hoher Lebensdauer aus.The advantages achieved by the invention are essentially to be seen in the fact that only the roller mounted on the needle head is used to drive the cutting device, and that the needle head is not actuated by a mechanism for the transition from the printing to the cutting process and vice versa, but is respectively pushed as far, that the roller is moved beyond the free end of the cam lever or up to this lever end. The slope of the curve section on the lever can be chosen to be small, so that the knife blade is advanced with a force that is greater than the thrust force exerted on the roller by the displacement drive. Overall, the dot matrix printer is characterized by an easily drivable cutting device of simple construction with low weight and correspondingly low susceptibility to failure and a long service life.

Im folgenden wird die Erfindung anhand eines Ausführungsbeispieles mit im Zusammenhang mit der Erfindung wesentliche Teile darstellenden Zeichnungen näher erläutert. Es zeigt

  • Fig. 1 eine Rückansicht des Inneren des Nadeldruckers (Ansicht in Blickrichtung I in Fig. 2),
  • Fig. 2 einen Schnitt nach der Linie 11-11 in Fig. 1,
  • Fig. 3 bis 6 je eine der Fig. 1 entsprechende, weiter vereinfachte Ansicht in vier verschiedenen Betriebszuständen.
The invention is explained in more detail below with the aid of an exemplary embodiment with drawings representing essential parts in connection with the invention. It shows
  • 1 is a rear view of the interior of the dot matrix printer (view in viewing direction I in Fig. 2),
  • 2 shows a section along the line 11-11 in Fig. 1,
  • FIGS. 3 to 6 each a further simplified view corresponding to FIG. 1 in four different operating states.

In den Zeichnungen ist der Nadelkopf 1 mit Ausnahme der an ihm auf einer abgewinkelten Achse 2 gelagerten Rolle 3, die zur Abschneidevorrichtung gehört, in dünneren Linien als die anderen Teile und in Fig. 3 bis 6 nur im Umriß dargestellt. Das nicht dargestellte Papierband wird von der ebenfalls nicht dargestellten Vorratsrolle durch einen Einführschlitz 4 und zwischen zwei Förderwalzen 5, die von einem Motor 6 angetrieben sind, auf einen Druckbalken 7 geführt, an dem das ortsfeste Gegenmesser 8 der Abschneidevorrichtung gebildet ist. Der Druckbalken 7 begrenzt zusammen mit einem darüber angeordneten Balken 9 einen Führungsschlitz für das bedruckte Papier.In the drawings, the needle head 1 is included Except for the roller 3 mounted on it on an angled axis 2 and belonging to the cutting device, shown in thinner lines than the other parts and only shown in outline in FIGS. 3 to 6. The paper tape, not shown, is guided from the supply roll, also not shown, through an insertion slot 4 and between two conveyor rollers 5, which are driven by a motor 6, onto a pressure bar 7, on which the stationary counter knife 8 of the cutting device is formed. The pressure bar 7, together with a bar 9 arranged above it, delimits a guide slot for the printed paper.

Der Nadelkopf 1 ist oben an einer Führungsleiste 11 gleitend und unten mittels Führungsrollen 12 und 13 an einer Rundstange 14 parallel zur Richtung der zu druckenden Zeilen verschiebbar geführt. Die Führungsleiste 11 und die Rundstange 14 sind ebenso wie der Druckbalken 7 mit einem Ende an der in Fig. 1 linken Seitenwand 15 und mit dem anderen Ende an einer rechten Zwischenwand 16 befestigt. Die unteren Führungsrollen 12 sind Profilrollen auf fest mit dem Nadelkopf 1 verbundenen Achsen. Die Achsen der oberen Führungsrollen 13 sind an den gabelförmig geschlitzten Enden einer in ihrer Mitte am Nadelkopf 1 befestigten Blattfeder 17 gelagert und zur sicheren Führung des Nadelkopfes 1 mit einer dessen Schwerkraft überschreitenden Federkraft an die Rundstange 14 gedrückt.The needle head 1 is slidable at the top of a guide bar 11 and at the bottom by means of guide rollers 12 and 13 on a round bar 14, displaceably guided parallel to the direction of the lines to be printed. The guide bar 11 and the round rod 14, like the pressure beam 7, are fastened at one end to the left side wall 15 in FIG. 1 and at the other end to a right intermediate wall 16. The lower guide rollers 12 are profile rollers on axially fixedly connected to the needle head 1. The axes of the upper guide rollers 13 are mounted on the fork-shaped slotted ends of a leaf spring 17 fastened in the middle to the needle head 1 and pressed against the round rod 14 with a spring force exceeding the force of gravity for the safe guidance of the needle head 1.

Zum Verschieben des Nadelkopfes 1 dient ein Seiltrieb. Dessen strichpunktiert dargestelltes, dehnungsfestes Seil 18 läuft von einem an der Seitenwand 15 befestigten Seilende über eine Umfangshälfte einer Rille einer am Nadelkopf 1 gelagerten Doppelrillen-Seilscheibe 19, eine an der Seitenwand 15 gelagerte Seilscheibe 20 und eine in einer Aussparung der Zwischenwand 16 gelagerte Seilscheibe 21 zu einer Treibscheibe 22, die eine Schraubenrille hat, zwischen der Zwischenwand 16 und einer rechten Seitenwand 23 angeordnet und von einem reversierbaren Schrittmotor 24 angetrieben ist. Von der Treibscheibe 22 läuft das Seil 18 weiter über eine in einer zweiten Aussparung der Zwischenwand 16 angeordnete Seilscheibe 25 und über die andere Umfangshälfte der anderen Rille der Doppelrillen-Seilscheibe 19 zur Zwischenwand 16, an der das andere Seilende befestigt ist.A cable drive serves to move the needle head 1. The stretch-proof rope 18 shown in dash-dot lines runs from a rope end fastened to the side wall 15 over a circumferential half of a groove of a double-groove rope pulley 19 mounted on the needle head 1, a rope pulley 20 mounted on the side wall 15 and a rope pulley 21 mounted in a recess in the intermediate wall 16 to a traction sheave 22, which has a screw groove, is arranged between the intermediate wall 16 and a right side wall 23 and is driven by a reversible stepper motor 24. From the traction sheave 22, the cable 18 continues over a cable pulley 25 arranged in a second recess in the intermediate wall 16 and over the other circumferential half of the other groove of the double-groove cable pulley 19 to the intermediate wall 16, to which the other cable end is fastened.

Wenn der Motor 24 mit der Treibscheibe 22 das Seil 18 in Richtung der in Fig. 1 eingetragenen Pfeile antreibt, wird der Nadelkopf 1 in Zeilenschreibrichtung, d. i. in Fig. 1 und 3 bis 6 von rechts nach links gezogen, wobei die Doppelrillen-Seilscheibe 19 in Richtung des in Fig. 1 eingetragenen Pfeiles rotiert. Wird das Seil 18 (nach Umkehr der Drehrichtung des Motors 24) in der entgegengesetzten Richtung angetrieben, wobei auch die Drehrichtung der Doppelrillen-Seilscheibe 19 umkehrt, so wird der Nadelkopf 1 in Fig. 1 und 3 bis 6 von links nach rechts gezogen.When the motor 24 with the traction sheave 22 drives the cable 18 in the direction of the arrows shown in FIG. 1, the needle head 1 is moved in the line writing direction, i.e. i. 1 and 3 to 6 pulled from right to left, the double-groove pulley 19 rotating in the direction of the arrow shown in FIG. 1. If the cable 18 (after reversing the direction of rotation of the motor 24) is driven in the opposite direction, the direction of rotation of the double-groove pulley 19 also being reversed, the needle head 1 in FIGS. 1 and 3 to 6 is pulled from left to right.

Die in Fig. 1 bis 5 in ihrer Ruhestellung und in Fig. 6 (in einer Stellung 27c) kurz vor dem Ende ihres Abschneidhubes dargestellte Messerklinge 27 ist am Gegenmesser 8 und am Balken 9 gleitend geführt. Eine Andruckrolle 28 auf einer Achse 29 hält die Messerklinge 27 am Gegenmesser 8 und Balken 9, ein Stift 30 und eine Rolle 31 (Fig. 1) führen die Messerklinge 27 seitlich.The knife blade 27 shown in FIGS. 1 to 5 in its rest position and in FIG. 6 (in a position 27c) shortly before the end of its cutting stroke is slidably guided on the counter knife 8 and on the bar 9. A pressure roller 28 on an axis 29 holds the knife blade 27 on the counter knife 8 and bar 9, a pin 30 and a roller 31 (FIG. 1) guide the knife blade 27 laterally.

Die Schneide 33 der Messerklinge 27 verläuft stumpfwinklig V-förmig, symmetrisch zur Mittelsenkrechten der Schneide 34 des Gegenmessers 8. Da die Schneiden 33 und 34 somit nicht parallel, sondern in einem spitzen Winkel zueinander verlaufen, wird jeweils an zwei kleinen Stellen geschnitten, so daß eine kleine Vorschubkraft für die Messerklinge 27 ausreicht. Der symmetrische Verlauf der Schneide 33 bewirkt, daß die Reaktionskraft beim Abschneidvorgang entgegengesetzt parallel zur Vorschubrichtung der Messerklinge 27 wirkt, also praktisch keine die seitliche Führung (Stift 30, Rolle 31 und den im folgenden noch erwähnten Bolzen 38 und die Rolle 39) belastende Komponente hat, so daß keine aufwendige Führung nötig und trotzdem die Gleitreibung vernachlässigbar ist.The cutting edge 33 of the knife blade 27 runs at an obtuse angle V-shaped, symmetrically to the perpendicular bisection of the cutting edge 34 of the counter knife 8. Since the cutting edges 33 and 34 do not run parallel but at an acute angle to one another, cutting is carried out in two small places, so that a small feed force for the knife blade 27 is sufficient. The symmetrical course of the cutting edge 33 has the effect that the reaction force during the cutting process acts in the opposite direction parallel to the feed direction of the knife blade 27, that is to say practically has no component which loads the lateral guide (pin 30, roller 31 and the pin 38 and roller 39 mentioned below) , so that no complex guidance is necessary and the sliding friction is nevertheless negligible.

Die Messerklinge 27 ist durch ein Distanzstück 36 fest mit einem Führungslappen 37 verbunden, der an der Leiste 11 gleitend durch einen Bolzen 38, der einen über den Führungslappen 37 greifenden Kopf hat, und eine Rolle 39 geführt ist. An einem Ansatz 40 der Leiste 11 sind der Bolzen 38 befestigt und die Rolle 39 gelagert.The knife blade 27 is fixedly connected by a spacer 36 to a guide tab 37 which is slidably guided on the bar 11 by a bolt 38 which has a head which extends over the guide tab 37 and a roller 39. The bolt 38 is fastened to a shoulder 40 of the strip 11 and the roller 39 is mounted.

Die Messerklinge 27 bildet einen Kurventräger für eine aus drei Abschnitten 41, 42, 43 bestehende Kurve eines ebenen Schubkurvengetriebes, dessen Antriebsglied die Rolle 3 ist. Der erste Kurvenabschnitt 41 verläuft an der Rückseite der Messerklinge (Messerklingenrükken) rechtwinklig zur Vorschubrichtung der Messerklinge, d. h. parallel zur Führung (11, 14) des Nadelkopfes 1 von einer Stelle, die dem Anfang der zu druckenden Zeilen zugeordnet ist, d. h. von der Stelle, an der sich die Rolle 3 in der in Fig. 1 ausgezogen dargestellten Ruhestellung des Nadelkopfes 1 befindet, bis wenig über die Stelle hinaus, an der sich die Rolle 3 am Ende der Zeilen befindet, an welcher der Nadelkopf und die Rolle in Fig. 1 und 4 mit 1 und 3a bezeichnet sind.The knife blade 27 forms a cam carrier for a curve consisting of three sections 41, 42, 43 of a flat thrust cam mechanism, the drive element of which is the roller 3. The first curve section 41 runs on the back of the knife blade (knife blade back) at right angles to the direction of advance of the knife blade, i. H. parallel to the guide (11, 14) of the needle head 1 from a position which is assigned to the beginning of the lines to be printed, d. H. from the point at which the roller 3 is in the rest position of the needle head 1 shown in solid line in FIG. 1 to a little beyond the point at which the roller 3 is at the end of the lines at which the needle head and the roller 1 and 4 are designated by 1 and 3a.

Der zweite Kurvenabschnitt 42 verläuft im wesentlichen spitzwinklig zum ersten Kurvenabschnitt 41 und ist an der diesem abgewandten Seite eines Kurvenhebels 44 gebildet. Der Kurvenhebel 44 ist am Führungslappen 37 um einen Zapfen 45 schwenkbar gelagert und liegt mit seinem freien Ende unter der Wirkung einer Zugfeder 46 an der Stelle des ersten Kurvenabschnitts 41 an, an welcher sich die Rolle 3 in ihrer erwähnten Stellung 3a befindet, wobei er mit einer Weichenzunge vergleichbar ist. Der Abstand des schwenkbar gelagerten Endes des Kurvenhebels 44 vom ersten Kurvenabschnitt 41 ist so groß, daß die Rolle 3 zwischen dem ersten Kurvenabschnitt 41 und dem Hebel 44 (in Fig. 1 von rechts nach links, vgl. Fig. 4) hindurch laufen kann. Der größte Abstand des zweiten Kurvenabschnitts 42 vom ersten 41 ist gleich dem Hub der Messerklinge 27, der wenig größer als der Abstand des Scheitels 47 von den Enden der stumpfwinklig V-förmig verlaufenden Schneide 33 ist.The second cam section 42 extends essentially at an acute angle to the first cam section 41 and is formed on the side of a cam lever 44 facing away from it. The cam lever 44 is pivotally mounted on the guide tab 37 about a pin 45 and rests with its free end under the action of a tension spring 46 at the location of the first cam section 41, at which the roller 3 is in its mentioned position 3a, with it is comparable to a switch tongue. The distance between the pivotably mounted end of the cam lever 44 from the first cam section 41 is so large that the roller 3 runs between the first cam section 41 and the lever 44 (from right to left in FIG. 1, see FIG. 4) can. The greatest distance of the second curve section 42 from the first 41 is equal to the stroke of the knife blade 27, which is slightly larger than the distance of the apex 47 from the ends of the obtuse-angled V-shaped cutting edge 33.

Der dritte Kurvenabschnitt 43 ist an dem ersten Kurvenabschnitt 41 zugewandten Rand eines Armes 48 gebildet, der einstückig mit der Messerklinge 27 ausgeführt ist. Der dritte Kurvenabschnitt 43 geht von einem Halbkreisbogen am Anfang des ersten Kurvenabschnitts 41 aus und verläuft zuerst kurz parallel in einem den Durchmesser der Rolle 3 wenig überschreitenden Abstand vom ersten Kurvenabschnitt 41, wodurch eine die Rolle 3 in der Ruhestellung des Nadelkopfes 1 aufnehmende Nische 49 (Fig. 1 und 4 bis 6) gebildet ist, dann spitzwinklig zum ersten Kurvenabschnitt 41 und übergreift schließlich das schwenkbar gelagerte Ende des Kurvenhebels 44 in einem Abstand, der wenig größer als der Durchmesser der Rolle 3 ist.The third curve section 43 is formed on the edge of an arm 48 facing the first curve section 41, which is made in one piece with the knife blade 27. The third curve section 43 starts from a semicircular arc at the beginning of the first curve section 41 and first runs briefly parallel at a distance from the first curve section 41 that does not exceed the diameter of the roller 3, as a result of which a niche 49 receiving the roller 3 in the rest position of the needle head 1 ( 1 and 4 to 6) is formed, then at an acute angle to the first cam section 41 and finally engages over the pivotably mounted end of the cam lever 44 at a distance which is slightly larger than the diameter of the roller 3.

Der Zapfen 45 befindet sich über einer Stelle des ersten Kurvenabschnitts 41, die von dessen in Fig. 1 rechten Anfang (Nische 49) einen kleineren Abstand hat als vom in dieser Figur linken Ende des ersten Kurvenabschnitts 41. Dementsprechend ist der Kurvensteigungswinkel des zweiten Kurvenabschnitts 42 kleiner als der des dritten Kurvenabschnitts 43.The pin 45 is located above a point of the first curve section 41 which is at a smaller distance from its right start (recess 49) in FIG. 1 than from the left end of the first curve section 41 in this figure. The curve inclination angle of the second curve section 42 is accordingly smaller than that of the third curve section 43.

Zwei Zugfedern 51 sind mit einem Ende an der Achse 29 der Andruckrolle 28 und mit dem anderen Ende an der Messerklinge 27 befestigt und halten diese kraftschlüssig mit dem ersten bzw. zweiten Kurvenabschnitt 41 bzw. 42 an der Rolle 3, wie im Zusammenhang mit der Wirkungsweise des Nadeldruckers noch näher erläutert wird.Two tension springs 51 are attached at one end to the axis 29 of the pressure roller 28 and at the other end to the knife blade 27 and hold them non-positively with the first and second curve sections 41 and 42 on the roller 3, as in connection with the mode of operation of the dot matrix printer is explained in more detail.

Die Messerklinge 27 hat beiderseits der Bahn, an welcher die Andruckrolle 28 auf ihr läuft, zwei trapezförmige Aussparungen 52 zur Herabsetzung ihrer Masse, damit eine kleine Beschleunigerkraft für den Vorschub der Messerklinge 27 genügt und Erschütterungen nur möglichst geringe Kräfte auf die Messerklinge 27 ausüben.The knife blade 27 has on both sides of the path on which the pressure roller 28 runs on it two trapezoidal cutouts 52 to reduce its mass so that a small accelerating force is sufficient for the advance of the knife blade 27 and vibrations exert only the lowest possible forces on the knife blade 27.

In der Ruhestellung des Nadelkopfes 1 befindet sich die an diesem gelagerte Rolle 3 in der Nische 49 der Messerklinge 27 (Fig. 1 und 3). Dabei ist die Messerklinge 27 in ihrer Ruhestellung fixiert. Zum zeilenweisen Drucken läuft der Nadelkopf 1 jeweils aus seiner Ruhestellung 1 in die Stellung 1a (Fig. 1 und 4) und zurück. Dabei läuft die Rolle 3 bis in ihre Stellung 3a und zurück auf dem ersten Kurvenabschnitt 41. Die Messerklinge 27 bleibt stehen. Der Kurvenhebel 44 ist in der Stellung 3a der Rolle angehoben (Stellung 44a) und kehrt in seine Ruhestellung zurück, während die Rolle 3 auf dem Kurvenabschnitt 41 aus der Stellung 3a in ihre Ruhestellung zurückläuft, in der sie mit 3 bezeichnet ist.In the rest position of the needle head 1, the roller 3 mounted on it is located in the recess 49 of the knife blade 27 (FIGS. 1 and 3). The knife blade 27 is fixed in its rest position. For line-by-line printing, the needle head 1 runs from its rest position 1 to position 1a (FIGS. 1 and 4) and back. The roller 3 runs to its position 3a and back on the first curve section 41. The knife blade 27 stops. The cam lever 44 is raised in the position 3a of the roller (position 44a) and returns to its rest position, while the roller 3 runs back on the curve section 41 from the position 3a to its rest position, in which it is designated by 3.

Wenn das Papierband abgeschnitten werden soll, wird der Nadelkopf 1 nach dem Drucken der letzten Zeile über die Stellung 1 a hinaus bis in die Stellung 1b (Fig. 1 und 5) verschoben, in welcher die Rolle sich in der Stellung 3b befindet. Nachdem durch Antrieb der Förderwalzen 5 das Papierband soweit gefördert wurde, daß sich die zu zerschneidende Stelle an den Schneiden 33 und 34 (Fig. 2) befindet, wird der Nadelkopf 1 aus der Stellung 1b in die Ruhestellung 1 zurückgezogen. Dabei läuft die Rolle aus der Stellung 3b zuerst auf dem zweiten Kurvenabschnitt 42, wobei sie die Messerklinge 27 nach unten schiebt. Dies ist aus Fig. 6 ersichtlich, welche den Nadelkopf und die Rolle in der Betriebsstellung 1 c bzw. 3c kurz vor dem Ende des Abschneidhubes der Messerklinge 27c zeigt. Nach dem Ende des Abschneidhubes verläßt die Rolle 3 den zweiten Kurvenabschnitt 42, und die Messerklinge 27 wird durch die Federn 51 und/oder, indem die Rolle 3 am dritten Kurvenabschnitt 43 läuft, in ihre Ruhelage zurückgeführt.If the paper tape is to be cut off, the needle head 1 after printing the last line is moved beyond position 1a to position 1b (FIGS. 1 and 5), in which the roll is in position 3b. After the paper belt has been conveyed so far by driving the conveyor rollers 5 that the point to be cut is at the cutting edges 33 and 34 (FIG. 2), the needle head 1 is withdrawn from the position 1b into the rest position 1. The roller runs from position 3b first on the second curve section 42, pushing the knife blade 27 downward. This can be seen from FIG. 6, which shows the needle head and the roller in the operating position 1 c or 3 c shortly before the end of the cutting stroke of the knife blade 27 c. After the end of the cutting stroke, the roller 3 leaves the second curve section 42, and the knife blade 27 is returned to its rest position by the springs 51 and / or by the roller 3 running on the third curve section 43.

Wie ersichtlich sind die Federn 51 nicht unbedingt nötig, weil der dritte Kurvenabschnitt 43 die Rückführung der Messerklinge 27 in ihre Ruhestellung zuverlässig bewirkt. Die Gleitreibung der Führung der Messerklinge 27 und des Führungslappens 37 genügt, wenn keine Erschütterungen auftreten, um die Messerklinge 27 in ihrer Ruhestellung zu halten, wenn der Nadelkopf aus seiner Ruhestellung 1 in seine Stellung 1a und zurück oder in die Stellung 1b läuft. Jedenfalls kann die Spannung der Federn 51 so klein sein, daß sie gegenüber der zum Überwinden des beim Abschneiden auftretenden Widerstandes erforderlichen Kraft vernachlässigbar ist. Auch für die Feder 46 genügt eine sehr kleine Spannung, so daß die zum Abheben des Kurvenhebels 44 in seine in Fig. 1 und 4 dargestellte Stellung 44a erforderliche Vorschubkraft der Rolle 3 vernachlässigbar ist.As can be seen, the springs 51 are not absolutely necessary because the third curve section 43 reliably brings the knife blade 27 back into its rest position. The sliding friction of the guidance of the knife blade 27 and the guide tab 37 is sufficient if no shocks occur in order to keep the knife blade 27 in its rest position, when the needle head runs from its rest position 1 into its position 1a and back or into position 1b. In any case, the tension of the springs 51 can be so small that it is negligible compared to the force required to overcome the resistance that occurs when cutting off. A very small tension is also sufficient for the spring 46, so that the feed force of the roller 3 required to lift the cam lever 44 into its position 44a shown in FIGS. 1 and 4 is negligible.

Die Kraft, mit welcher die auf dem zweiten Kurvenabschnitt 42 laufende Rolle 3 zum Vorschub der Messerklinge 27 verschoben werden muß, ist wegen der Neigung des zweiten Kurvenabschnitts 42 viel kleiner als der für den Abschneidvorgang von der Messerklinge 27 zu überwindende Widerstand, und dieser ist durch den abgewinkelten Verlauf der Schneide 33 der Messerklinge 27 klein gehalten. Vernachlässigbar ist auch die Kraft, welche die auf dem dritten Kurvenabschnitt 43 laufende Rolle 3 zur Rückführung der Messerklinge in ihre Ausgangslage aufwenden muß, denn auch dieser Kurvenabschnitt 43 ist geneigt; es muß nur die Gleitreibung der Messerklinge 27 und des Lappens 37 überwunden werden, und gegebenenfalls helfen die Federn 51 nach. Entsprechend dem kleineren Kurvensteigungswinkel des zweiten Kurvenabschnitts 42 und dem größeren Kurvensteigungswinkel des dritten Kurvenabschnitts 43 ist das Verhältnis der an der Rolle 3 aufzuwendenden Vorschubkraft für den zum Verschieben der Messerklinge 27 zu überwindenden Widerstand beim Messerklingenvorschub, bei dem die Rolle (3c in Fig. 6) auf dem zweiten Kurvenabschnitt 42 läuft und die Scherfestigkeit des Papiers überwinden muß, kleiner und beim Messerklingenrückzug, bei dem die Rolle 3 auf dem dritten Kurvenabschnitt 43 läuft und noch der geringe Reibungswiderstand der Führungen der Messerklinge 27 überwunden werden muß, größer. Damit wird die Kraft des Motors 24 für den Messerklingenantrieb optimal ausgenutzt. Die beim Abschneidevorgang auf den Nadelkopf 1 wirkende Reaktionskraft erhöht dessen Führungswiderstand nicht, weil sie von den Führungsrollen 12 aufgenommen wird.The force with which the roller 3 running on the second curve section 42 has to be displaced in order to advance the knife blade 27 is, because of the inclination of the second curve section 42, much smaller than the resistance to be overcome by the knife blade 27 for the cutting process, and this is through the angled course of the cutting edge 33 of the knife blade 27 is kept small. Also negligible is the force which the roller 3 running on the third curve section 43 must exert to return the knife blade to its starting position, because this curve section 43 is also inclined; it is only necessary to overcome the sliding friction of the knife blade 27 and the flap 37, and if necessary the springs 51 help. Corresponding to the smaller curve slope angle of the second curve section 42 and the larger curve slope angle of the third curve section 43, the ratio of the feed force to be exerted on the roller 3 for the resistance to be overcome for displacing the knife blade 27 during the knife blade advance, in which the roller (3c in FIG. 6) runs on the second curve section 42 and has to overcome the shear strength of the paper, smaller and with the knife blade retraction, in which the roller 3 on the third Curve section 43 runs and the low frictional resistance of the guides of the knife blade 27 has to be overcome, larger. The power of the motor 24 for the knife blade drive is thus optimally utilized. The reaction force acting on the needle head 1 during the cutting process does not increase its guide resistance because it is taken up by the guide rollers 12.

Aus diesen Gründen genügt beim vorliegenden Nadeldrucker ein in üblicher Weise nur zum Verschieben des Nadelkopfes 1 bemessener Antriebsmotor 24 - wie sich gezeigt hat - zum zusätzlichen Antrieb der beschriebenen Abschneidevorrichtung. Dabei ist zu bedenken, daß dieser Motor 24 bei einem schnell arbeitenden Nadeldrucker auch zur Überwindung der Massenträgheit des Nadelkopfes am Anfang dessen Vorschub- und Rückzugbewegung bemessen sein muß, und daß die Rolle 3 erst nach dem Anfang der Rückzugbewegung des Nadelkopfes 1 auf den geneigten zweiten Kurvenabschnitt 42 läuft, wobei der Motor 24 den Nadelkopf nicht mehr zu beschleunigen braucht und somit Kraftreserve zum Verschieben der Rolle 3 beim Abschneidevorgang hat.For these reasons, in the present needle printer, a drive motor 24, which is dimensioned in the usual way only for moving the needle head 1, is sufficient - as has been shown - for additionally driving the cutting device described. It should be borne in mind that this motor 24 must also be dimensioned in a fast-working dot matrix printer to overcome the inertia of the needle head at the beginning of its advancing and retracting movement, and that the roller 3 only after the beginning of the retracting movement of the needle head 1 on the inclined second one Curve section 42 runs, the motor 24 no longer having to accelerate the needle head and thus has reserve power to move the roller 3 during the cutting process.

Der vorliegende Nadeldrucker benötigt auch keine besondere Steuervorrichtung für den Vorschub und Rückzug der Messerklinge 27. Durch eine nicht aufwendige Ergänzung der Steuerschaltung für den Schrittmotor 24 der Nadelkopfverschiebevorrichtung kann erreicht werden, daß dieser Motor nach dem letzten Zeilenvorschub des Nadelkopfes 1 um einige Schritte weiter dreht, woraufhin die Messerklinge 27 beim nachfolgenden Rückzug des Nadelkopfes 1 ohne weiteres vorgeschoben und auch wieder zurückgezogen wird.The present dot matrix printer also does not require any special control device for the advancement and retraction of the knife blade 27. By means of an inexpensive addition to the control circuit for the stepping motor 24 of the needle head displacement device, it can be achieved that this motor rotates a few steps further after the last line feed of the needle head 1, whereupon the knife blade 27 is pushed forward and withdrawn again when the needle head 1 is subsequently withdrawn.

Damit ist ein Nadeldrucker geschaffen, der einfach ist und ein geringes Gewicht sowie kleine Abmessungen hat.This creates a dot matrix printer that is simple, light in weight and small in size.

Claims (7)

1. A needle printer having a needle head (1) which is guided (11-14, 17) so as to be displaceable to and fro in the line direction and which is connected to a shifting drive (18-22,24, 25), and having a cutting device (27-31, 33, 34, 36-49, 51, 52) with a knife (27) which can be driven by displacement of the needle head (1) to carry out its cutting motion and with which a fixed counterknife (8) is associated, characterised in that a knife blade (27), which extends over the length of the cut and which is guided in a fixed guide (8, 9, 28-31, 38-40) so as to be displaceable perpendicularly to the plane of the print carrier is provided, on its knife back averted from the knife-blade cutting edge (33), with a cam carrier having a flat com (41-43) which extends in the plane of the knife and along which a roller (3), mounted fixedly on the needle head (1), is movable, and in that the cam comprises a first straight cam portion (41) which is formed on the knife back (27) and which is parallel to the needle-head guide (11, 14), and has a second cam portion (42) which extends substantially at an acute angle to this (41) and which is formed on a com lever (44) which is arranged on the side, averted from the knife-blade cutting edge (33), of the first cam portion (41) and the one end of which is mounted for rotation (at 45) on the knife blade (27) and is at a distance from the first cam portion (41) which exceeds the diameter of the roller (3), and the free end of which butts like a switch-points tongue under spring bias against the end of the first cam portion (41) and which is associated with the line end, and in that the needle head is, at the end of its feed path associated with the printing of each line, in a position (1a) in which the roller (3a) projects at the most by its radius beyond the free end of the cam lever (44a), and in that provided for triggering the cutting operation is an extension of this feed path, at the end of which the needle head is in a position (1 b) in which the roller (3b) is moved beyond the free end of the cam lever (44), so that it returns, upon moving back of the needle head (1) to its rest position, by running along on the second cam portion (42) to the end, associated with the line start, of the first cam portion (41).
2. A needle printer according to claim 1, characterised in that the axis of rotation (journal 45) of the cam lever (44) is at a greater distance from the end of the first cam portion (41) which is associated with the line end than from the start of the first cam portion (41) which is associated with the line start.
3. A needle printer according to claim 1 or 2, characterised in that at least one spring (51), acting on the cam carrier (27, 44, 48) in the withdrawal direction of the knife blade (27), holds the cam portions (41, 42) in a force-locking manner against the roller (3) which is mounted on the needle head (1).
4. A needle printer according to one of claims 1 to 3, characterised in that the cutting edge (33) of the knife blade (27) extends at an obtuse angle, in a V-shaped manner, symmetrically to the central perpendicular line of the cutting edge (34) of the fixed counterknife (8).
5. A needle printer according to one of claims 1 to 4, characterised in that emanating from the start, associated with the line start, of the first cam portion (41) is a third cam portion (43) which extends substantially at an acute angle to the first cam portion (41) and is formed on the side, turned to this, of an arm (48) which is connected rigidly to the knife blade (27) and which engages over the rotatably-mounted end of the cam lever (44) at a distance which is greater by a tolerance than the diameter of the roller (3).
6. A needle printer according to claim 5, characterised in that the parts, associated with the line start, of the first and third cam portions (41 and 44) form a niche (49) which receives therebetween the roller (3) in the rest position of the needle head (1).
7. A needle printer according to one of claims 1 to 6, characterised in that the needle head (1) is guided on a guide rod (14) by means of guide rollers (12, 13) lying opposite each other, of which the rollers (12) facing the cutting edge (34) of the counterknife (8) are, for absorption of the reaction force upon the cutting operation, mounted on axes connected securely to the needle head (1) and the other rollers (13) are, for the reliable guidance of the needle head (1), pressed resiliently (leaf spring 17) against the guide rod (14).
EP80101205A 1979-04-02 1980-03-10 Wire printer with cutting device Expired EP0017014B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH304379 1979-04-02
CH3043/79 1979-04-02

Publications (2)

Publication Number Publication Date
EP0017014A1 EP0017014A1 (en) 1980-10-15
EP0017014B1 true EP0017014B1 (en) 1983-07-27

Family

ID=4247337

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80101205A Expired EP0017014B1 (en) 1979-04-02 1980-03-10 Wire printer with cutting device

Country Status (4)

Country Link
US (1) US4302119A (en)
EP (1) EP0017014B1 (en)
JP (1) JPS588997B2 (en)
DE (1) DE3064355D1 (en)

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US4544293A (en) * 1984-06-11 1985-10-01 Eaton Corporation Printer apparatus and cutting mechanism
US4815874A (en) * 1988-02-01 1989-03-28 Kroy Inc. Thermal printer and tape-ribbon cartridge with cut-off mechanism
US4917514A (en) * 1988-02-01 1990-04-17 Kroy Inc. Thermal printing device and tape supply cartridge embodying a tape cut-off mechanism
US5133615A (en) * 1989-09-07 1992-07-28 Tokyo Electric Co., Ltd. Ticket issuing machine
US5363123A (en) * 1992-07-14 1994-11-08 Hewlett-Packard Company Cutter drive for a computer driven printer/plotter
TW226004B (en) * 1993-05-10 1994-07-01 Siemens Nixdorf Inf Syst A cutting device for cutting prints in the printing machine
US5833380A (en) * 1995-11-21 1998-11-10 Seiko Epson Corporation Printer having cutting apparatus and protective device for use in a printer
US5971639A (en) * 1996-11-11 1999-10-26 Samsung Electro-Mechanics Co., Ltd. Paper cutting apparatus in a small-sized printer
US6113293A (en) * 1998-05-28 2000-09-05 Brady Worldwide, Inc. Label printer having lever actuated cutter
US6732619B2 (en) * 2001-11-01 2004-05-11 Brady Worldwide, Inc. Cutter mechanism
US7930958B2 (en) 2005-07-14 2011-04-26 Provo Craft And Novelty, Inc. Blade housing for electronic cutting apparatus
US20100269664A1 (en) * 2009-04-22 2010-10-28 Mike Majchrowski Servo pouch knife assembly
US8657512B2 (en) 2009-08-26 2014-02-25 Provo Craft And Novelty, Inc. Crafting apparatus including a workpiece feed path bypass assembly and workpiece feed path analyzer
US20110280999A1 (en) 2009-12-23 2011-11-17 Provo Craft And Novelty, Inc. Foodstuff Crafting Apparatus, Components, Assembly, and Method for Utilizing the Same

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JPS50115727A (en) * 1974-02-20 1975-09-10
DE2420841C3 (en) * 1974-04-30 1981-01-22 Walther Electronic Ag, 7921 Gerstetten Cutting device for recording media or the like
JPS52121404A (en) * 1976-04-05 1977-10-12 Ricoh Kk Carriage feeding mechanism for printer
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Also Published As

Publication number Publication date
DE3064355D1 (en) 1983-09-01
JPS55132289A (en) 1980-10-14
EP0017014A1 (en) 1980-10-15
US4302119A (en) 1981-11-24
JPS588997B2 (en) 1983-02-18

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