EP0393759B1 - Print gap adjustment mechanism in a printer - Google Patents

Print gap adjustment mechanism in a printer Download PDF

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Publication number
EP0393759B1
EP0393759B1 EP90200897A EP90200897A EP0393759B1 EP 0393759 B1 EP0393759 B1 EP 0393759B1 EP 90200897 A EP90200897 A EP 90200897A EP 90200897 A EP90200897 A EP 90200897A EP 0393759 B1 EP0393759 B1 EP 0393759B1
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EP
European Patent Office
Prior art keywords
carriage
printing
movement
printing head
gap
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 - Lifetime
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EP90200897A
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German (de)
French (fr)
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EP0393759A2 (en
EP0393759A3 (en
Inventor
Rolf Kirchhoff
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.)
PSI Printer Systems International GmbH
Original Assignee
PSI Printer Systems International GmbH
Philips Patentverwaltung GmbH
Philips Gloeilampenfabrieken NV
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Publication of EP0393759A2 publication Critical patent/EP0393759A2/en
Publication of EP0393759A3 publication Critical patent/EP0393759A3/en
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Publication of EP0393759B1 publication Critical patent/EP0393759B1/en
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    • 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
    • B41J25/304—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface
    • B41J25/308—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms
    • B41J25/3088—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms with print gap adjustment means on the printer frame, e.g. for rotation of an eccentric carriage guide shaft
    • 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
    • B41J25/304—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface
    • B41J25/308—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms

Definitions

  • the invention relates to a method for setting a printing gap in a printer, for. B. in a dot matrix printer.
  • the nip in a dot matrix printer is defined as the free distance between the ribbon attached to the printhead and the paper attached to the platen.
  • New high-performance print heads that work with needle frequencies between 2 and 3 kHz place high demands on compliance with the specified printing gap in order to be able to achieve the required font quality and these needle frequencies.
  • Electromechanical adjustment and automatic permanent pressure gap control are also known (see, for example, EP-A.0 292 102 or US-A-4 676 675).
  • the known setting methods or arrangements have the disadvantage that they are user-unfriendly, very complex and imprecise and fail with problematic forms or do not allow automatic processing of different form thicknesses.
  • the invention has for its object to provide an inexpensive and accurate way to adjust the printing gap for a dot matrix printer with multiple paper feed options and thus also constantly changing form thicknesses.
  • This object is achieved according to the invention in that the print head moves back and forth several times between two switching points and at the same time is moved forward in the direction of the print roller, that the contact between the roller and the print head is determined by changing a parameter characterizing the back and forth movement is that this change leads to a standstill of the forward movement when a certain value is reached and that the print head, starting from this position with the printing gap "zero", is moved back by the desired value of the printing gap.
  • the method enables precise adjustment with high reproducibility and requires little effort, since existing assemblies can be used. So z. B. no complex displacement or force sensor required. Since the contact between the print abutment and the print head is determined immediately, there is a low contact pressure when moving against the print abutment, so that no undesired elastic bends can occur in the printing unit which distort the measuring process.
  • the time required by the print head for the back and forth movement between two switching points is used as the characteristic parameter, the average time required by the print head for this measuring path from several movement cycles being used as a basis. It is also possible to use, as characteristic parameters, those recorded by the motor to generate the back and forth movement Use current or voltage values.
  • a DC motor drive of the printing carriage, which is already present in the printer, and an incremental linear scanning device, which is also already present, with a stationary increment ruler and a scanning element on the printing carriage are preferably used.
  • a stepper motor together with an eccentric guide shaft for the pressure carriage is preferably used to generate the forward and backward movement. The method according to the invention can thus be carried out predominantly with already existing components.
  • the printhead is slowly moved with the stepper motor towards the pressure abutment.
  • the horizontal drive is in operation by the DC motor, z. B. its current consumption and / or speed can be measured.
  • the current consumption increases or the speed decreases due to the additional friction in the horizontal drive.
  • These changes can e.g. B. be evaluated with threshold switches. When these switches respond, the pressure gap is zero.
  • the print head is then moved back by a number of steps corresponding to the desired print gap, and the print gap is adjusted to the desired value.
  • the corresponding sample value can be saved for each type of form and the stepper motor can thus be controlled directly if required.
  • An arrangement for carrying out the method according to the invention thus preferably contains a DC motor for the horizontal drive of the printing carriage, an incremental linear scanning device with a stationary one Incremental ruler and a scanning element attached to the slide, a stepper motor for moving the slide back and forth with the print head and electronics for controlling the back and forth or back and forth movement of the slide and for determining the pressure gap "zero", when the characteristic parameter has reached a certain value.
  • a print head carriage 1 with a print head 2 runs on two parallel circular guides 3, 4.
  • the front guide 3 is rotatably mounted eccentrically in side walls 5, 6.
  • a rear bearing 7 is designed as a support bearing and enables the pressure carriage 1 to be displaced at right angles to the rear shaft 4.
  • a toothed segment 8 is attached to the eccentric shaft 3, with which the shaft can be rotated. The eccentric is aligned so that a movement of the print head 2 at right angles to the pressure abutment, ie to the pressure roller 9, occurs when it is rotated.
  • With a stepper motor 10 which engages in the toothed segment 8, the pressure gap 19 can thus be set electrically.
  • the carriage 1 is driven by a DC horizontal motor 12 via a toothed belt 11.
  • An incremental linear scanning device with a stationary one is used for speed measurement and character preparation Increment ruler 13 and a scanning element 14 on the carriage 1.
  • the print head 2 With 15 needles of the print head 2 are designated.
  • the print head 2 is widened at its tip in order to avoid an impression with pressure-sensitive multiple uses.
  • the ribbon 16 is covered by an aperture 17 so that direct contact of the ribbon and paper is prevented.
  • the needles 15 print onto the paper 18 through an opening in the diaphragm 17.
  • the printing gap formed between the paper 18 and the ink ribbon 16 is designated by 19.
  • the scanning process is as follows: At the beginning of the process, the carriage 1 assumes a horizontal position in the printing area, and the printing head 2 is pivoted away. The horizontal motor 12 is then driven with a reduced constant current or constant voltage. The carriage 1 moves with the head 2 in the horizontal direction and, for. B. after a distance of 1 to 5/120 ", in each case reversed so that a back and forth movement takes place.
  • the measuring section 20 moves, for example, between two adjacent vertical sections 13a and 13b of the increment ruler 13 (see FIG The average time t m that the print head 2 requires for the measuring section 20 is determined from several movement cycles, and simultaneously with this back and forth movement the print head 2 becomes slow compared to the back and forth movement by the stepper motor 10 in the direction of the paper 18.
  • this value is regarded as a sign that the pressure gap 19 has reached the value "zero" and the forward movement of the Printhead 2 is stopped.
  • the stepper motor 10 then moves back by the desired steps required to set the desired pressure gap 19.
  • FIG. 3 schematically shows the measuring section between two increment sections 13a and 13b of the incremental ruler 13.
  • the length of the measuring section is designated by 20.
  • the reversal of the direction of movement follows at the ends of the measuring section.
  • the path of the print head 2 after shutdown is shown schematically in dashed lines at 21. As can be seen, the print head 2 still moves a certain distance beyond the limits 13a, 13b after the switch-off, before the reversal takes place.

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  • Common Mechanisms (AREA)
  • Character Spaces And Line Spaces In Printers (AREA)

Description

Die Erfindung bezieht sich auf ein Verfahren zur Einstellung eines Druckspaltes bei einem Drucker, z. B. bei einem Matrixnadeldrucker.The invention relates to a method for setting a printing gap in a printer, for. B. in a dot matrix printer.

Der Druckspalt in einem Nadeldrucker ist als der freie Abstand zwischen dem am Druckkopf anliegenden Farbband und dem am Druckwiderlager anliegenden Papier definiert. Neue Hochleistungsdruckköpfe, die mit Nadelfrequenzen zwischen 2 und 3 kHz arbeiten, stellen hohe Anforderungen an die Einhaltung des vorgegebenen Druckspaltes, um die geforderte Schriftqualität und diese Nadelfrequenzen realisieren zu können.The nip in a dot matrix printer is defined as the free distance between the ribbon attached to the printhead and the paper attached to the platen. New high-performance print heads that work with needle frequencies between 2 and 3 kHz place high demands on compliance with the specified printing gap in order to be able to achieve the required font quality and these needle frequencies.

Es ist bekannt, den Druckspalt manuell mechanisch durch Probieren einzustellen. Es ist ferner eine elektromechanische Einstellung und eine automatische ständige Druckspaltregelung bekannt (siehe z.B. EP-A.0 292 102 oder US-A-4 676 675). Die bekannten Einstellverfahren bzw. Anordnungen haben den Nachteil, daß sie bedienerunfreundlich, sehr aufwendig und ungenau sind und bei problematischen Formularen versagen bzw. keine automatische Verarbeitung von unterschiedlichen Formulardicken zulassen.It is known to set the pressure gap manually mechanically by trial and error. Electromechanical adjustment and automatic permanent pressure gap control are also known (see, for example, EP-A.0 292 102 or US-A-4 676 675). The known setting methods or arrangements have the disadvantage that they are user-unfriendly, very complex and imprecise and fail with problematic forms or do not allow automatic processing of different form thicknesses.

Der Erfindung liegt die Aufgabe zugrunde, für einen Nadeldrucker mit vielfachen Papierzuführmöglichkeiten und somit auch ständig wechselnden Formulardicken eine preiswerte und genaue Möglichkeit zur Einstellung des Druckspaltes zu schaffen. Diese Aufgabe wird gemäß der Erfindung dadurch gelöst, daß der Druckkopf zwischen zwei Schaltpunkten mehrfach hin und her bewegt und dabei gleichzeitig in Richtung auf die Druckwalze vorwärts bewegt wird, daß die Berührung zwischen Walze und Druckkopf durch Veränderung eines die Hin- und Herbewegung charakterisierenden Parameters ermittelt wird, daß diese Veränderung bei Erreichen eines bestimmten Wertes zum Stillstand der Vorwärtsbewegung führt und daß der Druckkopf, ausgehend von dieser Stellung mit dem Druckspalt "Null", um den gewünschten Wert des Druckspaltes zurück bewegt wird. Das Verfahren ermöglicht ein exaktes Einstellen mit hoher Reproduzierbarkeit und erfordert einen geringen Aufwand, da auf vorhandene Baugruppen zurückgegriffen werden kann. So wird z. B. kein aufwendiger Weg- bzw. Kraftsensor benötigt. Da die Berührung zwischen Druckwiderlager und Druckkopf sofort ermittelt wird, ergibt sich eine geringe Andruckkraft beim Anfahren gegen das Druckwiderlager, so daß keine unerwünschten elastischen Verbiegungen im Druckwerk auftreten können, die den Meßvorgang verfälschen.The invention has for its object to provide an inexpensive and accurate way to adjust the printing gap for a dot matrix printer with multiple paper feed options and thus also constantly changing form thicknesses. This object is achieved according to the invention in that the print head moves back and forth several times between two switching points and at the same time is moved forward in the direction of the print roller, that the contact between the roller and the print head is determined by changing a parameter characterizing the back and forth movement is that this change leads to a standstill of the forward movement when a certain value is reached and that the print head, starting from this position with the printing gap "zero", is moved back by the desired value of the printing gap. The method enables precise adjustment with high reproducibility and requires little effort, since existing assemblies can be used. So z. B. no complex displacement or force sensor required. Since the contact between the print abutment and the print head is determined immediately, there is a low contact pressure when moving against the print abutment, so that no undesired elastic bends can occur in the printing unit which distort the measuring process.

Vorzugsweise wird als charakteristischer Parameter die von dem Druckkopf bei der Hin- und Herbewegung zwischen zwei Schaltpunkten erforderliche Zeit verwendet, wobei die vom Druckkopf für diese Meßstrecke benötigte mittlere Zeit aus mehreren Bewegungszyklen zugrundegelegt wird. Es ist auch möglich, als charakteristischen Parameter die von dem Motor zur Erzeugung der Hin- und Herbewegung aufgenommenen Strom- oder Spannungswerte zu verwenden. Zur Erzeugung der Hin- und Herbewegung wird vorzugsweise ein bei dem Drucker ohnehin bereits vorhandener Gleichstrommotor-Antrieb des Druckschlittens und eine ebenfalls bereits vorhandene inkrementale Linearabtast-Einrichtung mit einem ortsfesten Inkrement-Lineal und einem Abtastelement am Druckschlitten verwendet. Zur Erzeugung der Vor- und Rückwärtsbewegung dient vorzugsweise ein Schrittmotor zusammen mit einer Exzenter-Führungswelle für den Druckschlitten. Das Verfahren gemäß der Erfindung kann somit überwiegend mit bereits vorhandenen Bauteilen durchgeführt werden. Zur Einstellung wird der Druckkopf mit dem Schrittmotor langsam in Richtung Druckwiderlager gefahren. Gleichzeitig ist der Horizontalantrieb durch den Gleichstrommotor in Betrieb, wobei z. B. seine Stromaufnahme und/oder Geschwindigkeit gemessen werden. Wenn der Druckkopf das Papier berührt, vergrößert sich die Stromaufnahme bzw. es verringert sich die Geschwindigkeit durch die zusätzliche Reibung im Horizontalantrieb. Diese Anderungen können z. B. mit Schwellwertschaltern ausgewertet werden. Beim Ansprechen dieser Schalter hat der Druckspalt den Wert Null. Danach wird der Druckkopf um eine dem gewünschten Druckspalt entsprechende Anzahl von Schritten zurückgefahren, und der Druckspalt ist auf den gewünschten Wert justiert. Bei der Verarbeitung von unterschiedlichen Formularen kann der entsprechende Abtastwert für jede Formularsorte gespeichert und bei Bedarf der Schrittmotor damit direkt angesteuert werden.Preferably, the time required by the print head for the back and forth movement between two switching points is used as the characteristic parameter, the average time required by the print head for this measuring path from several movement cycles being used as a basis. It is also possible to use, as characteristic parameters, those recorded by the motor to generate the back and forth movement Use current or voltage values. To generate the back and forth movement, a DC motor drive of the printing carriage, which is already present in the printer, and an incremental linear scanning device, which is also already present, with a stationary increment ruler and a scanning element on the printing carriage are preferably used. A stepper motor together with an eccentric guide shaft for the pressure carriage is preferably used to generate the forward and backward movement. The method according to the invention can thus be carried out predominantly with already existing components. The printhead is slowly moved with the stepper motor towards the pressure abutment. At the same time, the horizontal drive is in operation by the DC motor, z. B. its current consumption and / or speed can be measured. When the print head touches the paper, the current consumption increases or the speed decreases due to the additional friction in the horizontal drive. These changes can e.g. B. be evaluated with threshold switches. When these switches respond, the pressure gap is zero. The print head is then moved back by a number of steps corresponding to the desired print gap, and the print gap is adjusted to the desired value. When processing different forms, the corresponding sample value can be saved for each type of form and the stepper motor can thus be controlled directly if required.

Eine Anordnung zur Durchführung des Verfahrens gemäß der Erfindung enthält somit vorzugsweise einen Gleichstrommotor für den horizontalen Antrieb des Druckschlittens, eine inkrementale Linearabtast-Einrichtung mit einem ortsfesten Inkremental-Lineal und einem am Schlitten angebrachten Abtastelement, einen Schrittmotor zur Vor-und Rückverstellung des Schlittens mit dem Druckkopf und eine Elektronik zur Steuerung der Hin- und Her- bzw. Vor-und Rückbewegung des Schlittens und zur Ermittlung des Druckspaltes "Null", wenn der charakteristische Parameter einen bestimmten Wert erreicht hat.An arrangement for carrying out the method according to the invention thus preferably contains a DC motor for the horizontal drive of the printing carriage, an incremental linear scanning device with a stationary one Incremental ruler and a scanning element attached to the slide, a stepper motor for moving the slide back and forth with the print head and electronics for controlling the back and forth or back and forth movement of the slide and for determining the pressure gap "zero", when the characteristic parameter has reached a certain value.

In der Zeichnung ist in Fig. 1 bis 3 ein Ausführungsbeispiel des Gegenstandes gemäß der Erfindung dargestellt.

  • Fig. 1 zeigt eine Draufsicht auf einen Drucker,
  • Fig. 2 zeigt eine Einzelheit X gemäß Fig. 1, und
  • Fig. 3 zeigt eine weitere Einzelheit gemäß Fig. 1.
1 to 3, an embodiment of the object according to the invention is shown in the drawing.
  • 1 shows a top view of a printer,
  • FIG. 2 shows a detail X according to FIG. 1, and
  • FIG. 3 shows a further detail according to FIG. 1.

Ein Druckkopfschlitten 1 mit einem Druckkopf 2 läuft auf zwei parallelen Rundführungen 3, 4. Die vordere Führung 3 ist exzentrisch drehbar in Seitenwänden 5, 6 gelagert. Ein hinteres Lager 7 ist als Stützlager ausgebildet und ermöglicht eine Verschiebung des Druckschlittens 1 rechtwinklig zur hinteren Welle 4. An der Exzenterwelle 3 ist ein Zahnsegment 8 angebracht, mit dem die Welle verdreht werden kann. Der Exzenter ist so ausgerichtet, daß beim Verdrehen eine Bewegung des Druckkopfes 2 rechtwinklig zum Druckwiderlager, d. h. zur Druckwalze 9 entsteht. Mit einem Schrittmotor 10, der in das Zahnsegment 8 eingreift, läßt sich also der Druckspalt 19 elektrisch einstellen. Der Schlitten 1 wird über einen Zahnriemen 11 von einem Gleichstrom-Horizontalmotor 12 angetrieben. Zur Geschwindigkeitsmessung und zur Zeichenaufbereitung dient eine inkrementale Linearabtast-Einrichtung mit einem ortsfesten Inkrement-Lineal 13 und einem Abtastelement 14 am Schlitten 1. Mit 15 sind Nadeln des Druckkopfes 2 bezeichnet. Der Druckkopf 2 ist an seiner Spitze verbreitert, um einen Abdruck bei druckempfindlichen Mehrfach-Nutzen zu vermeiden. Das Farbband 16 wird durch eine Blende 17 abgedeckt, so daß ein direkter Kontakt von Farbband und Papier verhindert ist. Die Nadeln 15 drucken durch eine Öffnung in der Blende 17 auf das Papier 18. Mit 19 ist der zwischen dem Papier 18 und dem Farbband 16 gebildete Druckspalt bezeichnet.A print head carriage 1 with a print head 2 runs on two parallel circular guides 3, 4. The front guide 3 is rotatably mounted eccentrically in side walls 5, 6. A rear bearing 7 is designed as a support bearing and enables the pressure carriage 1 to be displaced at right angles to the rear shaft 4. A toothed segment 8 is attached to the eccentric shaft 3, with which the shaft can be rotated. The eccentric is aligned so that a movement of the print head 2 at right angles to the pressure abutment, ie to the pressure roller 9, occurs when it is rotated. With a stepper motor 10 which engages in the toothed segment 8, the pressure gap 19 can thus be set electrically. The carriage 1 is driven by a DC horizontal motor 12 via a toothed belt 11. An incremental linear scanning device with a stationary one is used for speed measurement and character preparation Increment ruler 13 and a scanning element 14 on the carriage 1. With 15 needles of the print head 2 are designated. The print head 2 is widened at its tip in order to avoid an impression with pressure-sensitive multiple uses. The ribbon 16 is covered by an aperture 17 so that direct contact of the ribbon and paper is prevented. The needles 15 print onto the paper 18 through an opening in the diaphragm 17. The printing gap formed between the paper 18 and the ink ribbon 16 is designated by 19.

Der Abtastvorgang läuft wie folgt ab:
Zu Beginn des Vorganges nimmt der Schlitten 1 eine horizontale Position im Druckbereich ein, und der Druckkopf 2 ist abgeschwenkt. Danach wird der Horizontalmotor 12 mit reduziertem Konstantstrom bzw. reduzierter Konstantspannung angesteuert. Dabei bewegt sich der Schlitten 1 mit dem Kopf 2 in Horizontalrichtung und wird, z. B. nach einer Strecke von 1 bis 5/120", jeweils reversiert, so daß eine Hin- und Herbewegung erfolgt. Die Meßstrecke 20 bewegt sich z. B. zwischen zwei nebeneinanderliegenden senkrechten Abschnitte 13a und 13b des Inkrement-Lineals 13 (siehe Fig. 3). Die mittlere Zeit tm, die der Druckkopf 2 für die Meßstrecke 20 benötigt, wird aus mehreren Bewegungszyklen ermittelt. Gleichzeitig mit dieser Hin-und Herbewegung wird der Druckkopf 2 langsam im Vergleich zu der Hin- und Herbewegung durch den Schrittmotor 10 in Richtung auf das Papier 18 gefahren. Sobald sich die Zeit tm zum Durchlauf der Meßstrecke 20 um einen bestimmten vorgegebenen Faktor erhöht, wird dieser Wert als Zeichen dafür angesehen, daß der Druckspalt 19 den Wert "Null" erreicht hat, und die Vorwärtsbewegung des Druckkopfes 2 wird gestoppt. Danach fährt der Schrittmotor 10 um die gewünschten Schritte zurück, die zur Einstellung des gewünschten Druckspaltes 19 erforderlich sind.The scanning process is as follows:
At the beginning of the process, the carriage 1 assumes a horizontal position in the printing area, and the printing head 2 is pivoted away. The horizontal motor 12 is then driven with a reduced constant current or constant voltage. The carriage 1 moves with the head 2 in the horizontal direction and, for. B. after a distance of 1 to 5/120 ", in each case reversed so that a back and forth movement takes place. The measuring section 20 moves, for example, between two adjacent vertical sections 13a and 13b of the increment ruler 13 (see FIG The average time t m that the print head 2 requires for the measuring section 20 is determined from several movement cycles, and simultaneously with this back and forth movement the print head 2 becomes slow compared to the back and forth movement by the stepper motor 10 in the direction of the paper 18. As soon as the time t m for passing through the measuring section 20 increases by a certain predetermined factor, this value is regarded as a sign that the pressure gap 19 has reached the value "zero" and the forward movement of the Printhead 2 is stopped. The stepper motor 10 then moves back by the desired steps required to set the desired pressure gap 19.

Fig. 3 zeigt schematisch die Meßstrecke zwischen zwei Inkrement-Abschnitten 13a und 13b des Inkremental-Lineals 13. Dabei ist die Länge der Meßstrecke mit 20 bezeichnet. Die Umkehrung der Bewegungsrichtung folgt jeweils an den Enden der Meßstrecke. Mit 21 ist schematisch gestrichelt der Weg des Druckkopfes 2 nach Abschaltung eingezeichnet. Wie man sieht, bewegt sich der Druckkopf 2 jeweils nach Abschaltung noch eine gewisse Strecke über die Begrenzungen 13a, 13b hinaus, bevor die Umkehrung erfolgt.3 schematically shows the measuring section between two increment sections 13a and 13b of the incremental ruler 13. The length of the measuring section is designated by 20. The reversal of the direction of movement follows at the ends of the measuring section. The path of the print head 2 after shutdown is shown schematically in dashed lines at 21. As can be seen, the print head 2 still moves a certain distance beyond the limits 13a, 13b after the switch-off, before the reversal takes place.

Claims (6)

  1. A method of adjusting a printing gap in a printer, for example, a matrix needle printer, characterized in that
    a) the printing head (2) is reciprocated several times between two switching points (13a, 13b) and is simultaneously moved forward in the direction of the platen (9),
    b) the contact between the paper and the printing head (2) is determined by variation of a parameter characteristic of the reciprocating movement,
    c) this variation results in stopping of the forward movement when a given value is reached, and
    d) the printing head (2), starting from this position in which the printing gap is at "zero", is moved back over the desired value of the printing gap ( 19 ).
  2. A method as claimed in Claim 1, characterized in that the characteristic parameter is the time required by a printing head (2) for the reciprocating movement between two switching points (13a, 13b), set against the average time required by the printing head (2) for this measurement path (20) as determined from several movement cycles.
  3. A method as claimed in Claim 1, characterized in that the characteristic parameter is the value of the current or voltage consumed by the direct current motor (12) for producing the reciprocating movement.
  4. A method as claimed in any one of Claims 1 to 3, characterized in that, for producing the reciprocating movement, use is made of the direct current motor (12) provided for the horizontal movement of the printing carriage and of an incremental linear scanning device having a stationary incremental ruler (13) and a scanning element (14) provided at the carriage (1).
  5. A method as claimed in any one of Claims 1 to 4, characterized in that a stepping motor 10 for producing the forward and backward movement of the carriage (1) with the printing head (2).
  6. A device for carrying out a method as claimed in any one of Claims 1 to 5, comprising a direct current motor for the horizontal drive of the printing carriage (1) and a stepping motor (10) for forward and backward displacement of the carriage (1) with the printing head (2), characterized by an incremental linear scanning device having a stationary increment ruler (13) and a scanning element (14) secured to the carriage (1), and an electronic system for controlling the reciprocating movement and the forward and backward movement of the carriage and setting the printing gap to "zero" when the characteristic parameter has reached a given value.
EP90200897A 1989-04-21 1990-04-12 Print gap adjustment mechanism in a printer Expired - Lifetime EP0393759B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3913073A DE3913073A1 (en) 1989-04-21 1989-04-21 METHOD FOR ADJUSTING A PRINT GAP IN A PRINTER
DE3913073 1989-04-21

Publications (3)

Publication Number Publication Date
EP0393759A2 EP0393759A2 (en) 1990-10-24
EP0393759A3 EP0393759A3 (en) 1991-07-24
EP0393759B1 true EP0393759B1 (en) 1994-07-06

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EP90200897A Expired - Lifetime EP0393759B1 (en) 1989-04-21 1990-04-12 Print gap adjustment mechanism in a printer

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US (1) US5009526A (en)
EP (1) EP0393759B1 (en)
JP (1) JPH02295781A (en)
DE (2) DE3913073A1 (en)

Families Citing this family (13)

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DE4113648A1 (en) * 1991-04-26 1992-10-29 Philips Patentverwaltung METHOD FOR ADJUSTING A PRINT SPLIT IN A PRINTER, E.g. A MATRIX PRINTER, AND ARRANGEMENT FOR IMPLEMENTING THE METHOD
US5227809A (en) * 1991-06-17 1993-07-13 Tektronix, Inc. Automatic print head spacing mechanism for ink jet printer
JPH0538851A (en) * 1991-08-07 1993-02-19 Seiko Epson Corp Printing apparatus
US5518324A (en) * 1993-01-29 1996-05-21 International Business Machines Corporation Platen to print head gap adjustment arrangement
US5529405A (en) * 1993-02-01 1996-06-25 International Business Machines Corporation Manual control/override for automatic forms thickness adjustment
JP2880627B2 (en) * 1993-06-25 1999-04-12 東芝テック株式会社 Print gap adjustment device
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Also Published As

Publication number Publication date
DE59006336D1 (en) 1994-08-11
EP0393759A2 (en) 1990-10-24
US5009526A (en) 1991-04-23
JPH02295781A (en) 1990-12-06
DE3913073A1 (en) 1990-10-25
EP0393759A3 (en) 1991-07-24

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