EP0008040B1 - Magnetic brush development apparatus for electrostatic charge images - Google Patents

Magnetic brush development apparatus for electrostatic charge images Download PDF

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Publication number
EP0008040B1
EP0008040B1 EP79102655A EP79102655A EP0008040B1 EP 0008040 B1 EP0008040 B1 EP 0008040B1 EP 79102655 A EP79102655 A EP 79102655A EP 79102655 A EP79102655 A EP 79102655A EP 0008040 B1 EP0008040 B1 EP 0008040B1
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EP
European Patent Office
Prior art keywords
magnetic brush
doctor blade
magnetic
roller
developer
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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
EP79102655A
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German (de)
French (fr)
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EP0008040A1 (en
Inventor
Hartmut Dr. Bock
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Hoechst AG
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Hoechst AG
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Priority to AT79102655T priority Critical patent/ATE235T1/en
Publication of EP0008040A1 publication Critical patent/EP0008040A1/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush

Definitions

  • the invention relates to a magnetic brush developing device for electrostatic charge images on a photoconductive recording layer, in which a developer of toner and magnetic carrier particles is applied to the charge images on which the toner adheres, and with a doctor blade, which is applied to the magnetic brush roller, the amount of dosed by the magnetic brush roller used for developing carrier particles and is brought up to the end faces of the roller at the roller ends.
  • Such a development device is known from DE-OS 2 436 890, in which the carrier particles of the developer are removed from the photoconductive or dielectric recording layer by the action of magnetic forces after completion of the development process.
  • a magnet which is designed, for example, as a magnetic roller, is arranged at a close distance from the recording layer with the charge images. The distance between the magnet and the recording layer must be such that the carrier particles cannot be pinched between the layer and the magnet.
  • DE-OS 2162 842 describes a cascade development device for an electrostatic copying machine which has a collecting device for removing the carrier particles adhering to the surface of the photoconductor drum.
  • the collecting device consists of a thin elastic material, for example plastic, which does not touch the photoconductor drum and has a collecting edge.
  • the collecting edge of the sealing strip is arranged at an adjustable distance from the photoconductor drum, which corresponds to approximately one tenth to approximately half the carrier particle diameter. Additional wiping devices for the sealing strip are provided as little as a magnetic roller.
  • U.S. Patent 3,884,571 relates to a developing device having a developer wiping device which extends in the form of a trough in the axial direction along a drum immediately below the space between a developing station and the photoconductive recording surface of the drum.
  • the bottom surface of the trough includes an upward angled wiper lip located near the surface of the drum that catches the developer trickling down from the development station.
  • the developer caught in the trough is conveyed to an outlet opening with the aid of an endless belt. There is no provision for the developer to be removed from the photoconductive recording layer by means of a magnetic roller.
  • the object of the invention is to obtain the most uniform possible discharge of carrier particles over the squeegee length and to achieve a discharge value corresponding to the value in the center of the squeegee in the squeegee transition areas near the end faces of the magnetic brush roller.
  • the two wipers are arranged in the direction of movement of the photoconductive recording layer after the development station.
  • the advantage is achieved that in the area of the doctor blade transition zones, a significantly lower proportion of carrier particles is discharged compared to known development devices, so that a downstream magnetic stripper can be used, which can be produced inexpensively in a static design, and which has the low discharge in the middle of the development zone accumulates over long periods of time without having to be emptied due to overfilling, and to largely avoid disturbances in other components of the copying machine which are caused by carrier particles which adhere to the photoconductive recording layer.
  • the carrier particles are not removed from the recording layer after the development station, they cause local transmission disturbances, sand the fixing rollers of the copying machine and can penetrate into bearings, which can thereby “seize up”.
  • a magnetic brush developing device 1 shown in FIG. 1 for an electrostatic copying machine is adjacent to a drum 2, the surface of which is provided with a photoconductive recording layer 3 and which rotates in the direction of the arrow P.
  • the or the electrostatic charge images to be developed are located on the recording layer 3.
  • the developer is known to consist of toner and carrier particles. The latter are generally magnetic.
  • the electrostatic charge images attract the toner that adheres to them and develops the charge images into powder images.
  • the carrier particles are discharged from the development area through the photoconductive recording layer 3 and are removed from the photoconductive recording layer 3 by a magnetic stripper 25 arranged after the developing device 1.
  • the magnetic brush roller 4 rotates in the same direction of rotation as the drum 2, which rotates in the direction of the arrow P 'and carries on its surface a developer fur 5, which is wiped off by a doctor blade 6, which is shown horizontally in FIG. 1, but also can be inclined to the surface of the magnetic brush roller 4 in any other direction.
  • the two wipers 7', 7" consist of non-magnetic , elastic material and are in contact with the photoconductive recording layer 3 so that they enclose an angle between 5 ° to 10 ° with the tangent t to the recording layer at the point of contact of the wipers.
  • the wipers 7 ', 7 "form an angle between 45 ° and 90 ° with the doctor blade 6.
  • the storage container 15 for the developer supply 11 has a bent edge 13, on which the squeegee 6 and the wipers 7 ', 7 "are fastened by means of a screw 9.
  • each wiper 7', 7" is made of two angled sheets 8, 8 'edged, of which the lower plate rests on the squeegee 6.
  • In the edge 13 there is an elongated hole 26 so that it is possible to move the screw 9 in the elongated hole and thereby to change the distance of the doctor blade 6 from the surface of the magnetic brush roller 4.
  • the surface of the cylinder sleeve 18 of the magnetic brush roller 4 is provided with grooves 14 which promote the development of the developer fur 5.
  • the doctor blade 6 has a left transition zone 6 'and a right transition zone 6 ", these are the regions near the end faces 18', 18" of the cylinder sleeve 18. In the transition zones 6 ', 6 ", the wiping edge 27 of the doctor blade 6 extends downward
  • each wiper 7', 7 covers one of the transition zones 6 'and 6 "of the doctor blade 6 outwards and inwards, the overlap inwards in the direction of the doctor blade
  • the center line 24 is at least 4 mm, while the overlap is generally 10 mm or larger in the outside.
  • a wiper has the dimensions 18 mm x 2 mm and is 30 mm wide.
  • the elastic wipers 7 ', 7 "prevent the discharge of carrier particles 12 from the photoconductive recording layer 3 in the area of the doctor blade transition zones 6 ', 6", so that the stripped carrier particles can be attracted by the magnetic field of the magnetic brush roller 4 with ease.
  • FIG 3 shows the structure of the magnetic brush roller 4, which has magnets 17 within the cylinder sleeve 18 for generating the required magnetic field for the developer fur.
  • a cover 20 closes off the developing device from above, while a side part 16 surrounds the storage container 15. An opening is provided between the side part 16 and the cover 20, in the area of which the magnetic brush roller 4 is arranged close to the photoconductive recording layer 3.
  • the side part 16 is connected to a base plate 22 which is fastened to a frame 23 by means of screws. Behind the magnetic brush roller 4 there is a collector 19, the stripping plate 21 of which runs tangentially to the surface of the cylinder sleeve 18 of the magnetic brush roller 4 in order to strip the developer fur, not shown, from its surface.
  • the stripped developer passes from the collector 19 into a circulating device 28, for example a screw conveyor, which circulates the developer.
  • doctor blade 6 and the wipers 7 ', 7 is similar to that in FIG. 1 and is therefore not described again.

Abstract

Disclosed is a magnetic brush device for use in a photocopy machine for applying a developer comprised of a toner and magnetic carrier particles to electrostatic charge images on a photoconductive recording medium on a rotating drum, comprising a magnetic brush roller rotatably mounted axially parallel and in spaced relationship to the drum; a doctor blade positioned adjacent the magnetic brush roller for metering the quantity of developer carried by the roller, this doctor blade converging to a point substantially adjacent the surface of the magnetic brush roller in the regions near both ends of the roller, to define a transition zone at each end thereof; and two elastic wiper members comprised of non-magnetic material mounted to bear against the drum, one in each of the transition zones, for wiping the magnetic carrier particles from the drum and for limiting the width of the developer applied by the magnetic brush roller to the drum.

Description

Die Erfindung betrifft eine Magnetbürsten-Entwicklungsvorrichtung für elektrostatische Ladungsbilder auf einer fotoleitfähigen Aufzeichnungsschicht, bei der ein Entwickler aus Toner und magnetischen Trägerteilchen auf die Ladungsbilder aufgebracht wird, auf denen der Toner haftet, und mit einer Rakel, die an der Magnetbürstenwalze anliegt, die Menge der von der Magnetbürstenwalze zum Entwickeln eingesetzten Trägerteilchen dosiert und an den Walzenenden an die Stirnflächen der Walze herangeführt ist.The invention relates to a magnetic brush developing device for electrostatic charge images on a photoconductive recording layer, in which a developer of toner and magnetic carrier particles is applied to the charge images on which the toner adheres, and with a doctor blade, which is applied to the magnetic brush roller, the amount of dosed by the magnetic brush roller used for developing carrier particles and is brought up to the end faces of the roller at the roller ends.

Eine derartige Entwicklungsvorrichtung ist aus der DE-OS 2 436 890 bekannt, bei der die Trägerteilchen des Entwicklers nach Abschluss des Entwicklungsvorganges durch Einwirkung von Magnetkräften von der fotoleitenden oder dielektrischen Aufzeichnungsschicht entfernt werden. Dazu wird ein Magnet, der beispielsweise als Magnetwalze ausgebildet ist, im engen Abstand zu der Aufzeichnungsschicht mit den Ladungsbildern angeordnet. Der Abstand zwischen dem Magneten und der Aufzeichnungsschicht muss dabei so bemessen sein, dass die Trägerteilchen zwischen der Schicht und dem Magneten nicht eingeklemmt werden können.Such a development device is known from DE-OS 2 436 890, in which the carrier particles of the developer are removed from the photoconductive or dielectric recording layer by the action of magnetic forces after completion of the development process. For this purpose, a magnet, which is designed, for example, as a magnetic roller, is arranged at a close distance from the recording layer with the charge images. The distance between the magnet and the recording layer must be such that the carrier particles cannot be pinched between the layer and the magnet.

Die DE-OS 2162 842 beschreibt eine Kaskadenentwicklungsvorrichtung für ein elektrostatisches Kopiergerät, das eine Auffangvorrichtung für das Entfernen der an der Oberfläche der Fotoleitertrommel haftenden Trägerteilchen aufweist. Die Auffangvorrichtung besteht aus einem die Fotoleitertrommel nicht berührenden, dünnen elastischen Material, beispielsweise Kunststoff gebildeten Dichtungsstreifen, der eine Auffangkante besitzt. Die Auffangkante des Dichtungsstreifens ist von der Fotoleitertrommel in einem einstellbaren Abstand angeordnet, der etwa einem Zehntel bis etwa der Hälfte des Trägerteilchendurchmessers entspricht. Zusätzliche Abstreifvorrichtungen zu dem Dichtungsstreifen sind ebensowenig wie eine Magnetwalze vorgesehen.DE-OS 2162 842 describes a cascade development device for an electrostatic copying machine which has a collecting device for removing the carrier particles adhering to the surface of the photoconductor drum. The collecting device consists of a thin elastic material, for example plastic, which does not touch the photoconductor drum and has a collecting edge. The collecting edge of the sealing strip is arranged at an adjustable distance from the photoconductor drum, which corresponds to approximately one tenth to approximately half the carrier particle diameter. Additional wiping devices for the sealing strip are provided as little as a magnetic roller.

Die US-Patentschrift 3 884 571 betrifft eine Entwicklungsvorrichtung mit einer Abstreifvorrichtung für den Entwickler, die sich in Gestalt eines Troges in axialer Richtung längs einer Trommel unmittelbar unterhalb des Raumes zwischen einer Entwicklungsstation und derfotoleitfähigen Aufzeichnungsfläche der Trommel erstreckt. Die Bodenfläche des Troges umfasst eine nach aufwärts gerichtete, abgewinkelte Abstreiflippe, die nahe der Oberfläche der Trommel angeordnet ist und den Entwickler auffängt, der von der Entwicklungsstation herabrieselt. Der im Trog aufgefangene Entwickler wird mit Hilfe eines endlos umlaufenden Bandes zu einer Austrittsöffnung gefördert. Eine Abnahme des Entwicklers von der fotoleitfähigen Aufzeichnungsschicht mittels einer Magnetwalze ist nicht vorgesehen.U.S. Patent 3,884,571 relates to a developing device having a developer wiping device which extends in the form of a trough in the axial direction along a drum immediately below the space between a developing station and the photoconductive recording surface of the drum. The bottom surface of the trough includes an upward angled wiper lip located near the surface of the drum that catches the developer trickling down from the development station. The developer caught in the trough is conveyed to an outlet opening with the aid of an endless belt. There is no provision for the developer to be removed from the photoconductive recording layer by means of a magnetic roller.

Bei den Entwicklungsvorrichtungen, die zum Antragen des Entwicklers an die fotoleitfähige Aufzeichnungsschicht eine Magnetwalze verwenden, von deren Oberfläche eine Rakel den Entwickler abstreift, zeigt sich im Bereich des Rakelübergangs, das ist die Rakelzone nahe den Stirnflächen der Magnetwalze, ein erhöhter Austrag von Trägerteilchen auf der fotoleitfähigen Aufzeichnungsschicht, im Vergleich zu der Rakelmitte. Dadurch wird es notwendig, die Sammler für den Entwickler für unterschiedliche Aufnahme über die Länge der Rakel zu konzipieren, wodurch deren Herstellung verteuert wird.In the case of the development devices which use a magnetic roller for applying the developer to the photoconductive recording layer, from the surface of which a doctor blade wipes the developer, in the area of the doctor blade transition, that is the doctor zone near the end faces of the magnetic roller, there is an increased discharge of carrier particles on the photoconductive recording layer compared to the center of the doctor blade. This makes it necessary to design the collectors for the developer for different receptacles over the length of the squeegee, making their manufacture more expensive.

Aufgabe der Erfindung ist es, über die Rakellänge einen möglichst gleichmässigen Austrag an Trägerteilchen zu erhalten und in den Rakel- übergangsbereichen nahe den Stirnflächen der Magnetbürstenwalze einen Austragswert entsprechend dem Wert in der Rakelmitte zu erreichen.The object of the invention is to obtain the most uniform possible discharge of carrier particles over the squeegee length and to achieve a discharge value corresponding to the value in the center of the squeegee in the squeegee transition areas near the end faces of the magnetic brush roller.

Diese Aufgabe wird erfindungsgemäss dadurch gelöst, dass neben der Rakel zwei elastische Abstreifer aus nichtmagnetischem Material vorgesehen sind, die an der fotoleitfähigen Aufzeichnungsschicht anliegen und die Trägerteilchen von dieser abstreifen, und dass in der Draufsicht in Richtung Rakel im Bereich einer linken und im Bereich einer rechten Übergangszone der Rakel je einer der Abstreifer so angeordnet ist, dass er die Entwickelbreite der Magnetbürstenwalze begrenzt.This object is achieved according to the invention in that, in addition to the doctor blade, two elastic wipers made of non-magnetic material are provided, which abut the photoconductive recording layer and strip the carrier particles therefrom, and in the top view in the direction of the doctor blade in the area of a left and in the area of a right Transition zone of the doctor blade one of the wipers is arranged so that it limits the development width of the magnetic brush roller.

Die beiden Abstreifer sind in Bewegungsrichtung der fotoleitfähigen Aufzeichnungsschicht nach der Entwicklungsstation angeordnet.The two wipers are arranged in the direction of movement of the photoconductive recording layer after the development station.

Die vorteilhafte Ausgestaltung der Erfindung ergibt sich aus den Merkmalen der Patentansprüche 2 bis 6.The advantageous embodiment of the invention results from the features of claims 2 to 6.

Mit der Erfindung wird der Vorteil erzielt, dass im Bereich der Rakelübergangszonen im Vergleich zu bekannten Entwicklungsvorrichtungen ein wesentlich niedrigerer Anteil an Trägerteilchen ausgetragen wird, so dass ein nachgeschalteter, kostengünstig in statischer Ausführung herstellbarer Magnetabstreifer verwendbar ist, der den geringen Austrag in der Mitte der Entwikkelzone über lange Zeiten hin sammelt, ohne wegen Überfüllung geleert werden zu müssen, und dass Störungen in anderen Baugruppen des Kopiergeräts, die durch Trägerteilchen verursacht werden, die an der fotoleitfähigen Aufzeichnungsschicht haften, weitgehend vermieden werden. Bekannterweise erzeugen die Trägerteilchen, falls sie nach der Entwicklungsstation nicht von der Aufzeichnungsschicht entfernt werden, lokale Übertragungsstörungen, schmirgeln die Fixierwalzen des Kopiergeräts und können in Lager eindringen, die sich dadurch «festfressen» können.With the invention, the advantage is achieved that in the area of the doctor blade transition zones, a significantly lower proportion of carrier particles is discharged compared to known development devices, so that a downstream magnetic stripper can be used, which can be produced inexpensively in a static design, and which has the low discharge in the middle of the development zone accumulates over long periods of time without having to be emptied due to overfilling, and to largely avoid disturbances in other components of the copying machine which are caused by carrier particles which adhere to the photoconductive recording layer. As is known, if the carrier particles are not removed from the recording layer after the development station, they cause local transmission disturbances, sand the fixing rollers of the copying machine and can penetrate into bearings, which can thereby “seize up”.

Mit der Erfindung werden derartige Schwierigkeiten vermieden, so dass die Betriebssicherheit des Kopiergeräts erhöht wird.Such difficulties are avoided with the invention, so that the operational reliability of the copying machine is increased.

Im folgenden wird die Erfindung anhand der Zeichnungen näher erläutert.The invention is explained in more detail below with reference to the drawings.

Es zeigen:

  • Fig. 1 eine Seitenansicht im Schnitt einer Entwicklungsvorrichtung mit einer Magnetbürstenwalze und mit Abstreifern, Fig. 2 eine schematische Ansicht der Magnetbürstenwalze, einer Ra- Kel und der Abstreifer nach Fig. 1, und Fig. 3 eine Seitenansicht im Schnitt einer Entwicklungsvorrichtung ähnlich zu derjenigen nach Fig. 1.
Show it:
  • Fig. 1 is a side sectional view of a developing device with a magnetic brush roll and with scrapers, Fig. 2 is a schematic view of the magnetic brush roll, a Ra K el and the stripper of Fig. 1 and Fig. 3 is a side sectional view of a developing device similar to that of FIG. 1.

Eine in Fig. 1 dargestellte magnetbürsten-Entwicklungsvorrichtung 1 für ein elektrostatisches Kopiergerät grenzt an eine Trommel 2 an, deren Oberfläche mit einer fotoleitfähigen Aufzeichnungsschicht 3 versehen ist und die sich in Richtung des Pfeils P dreht. Auf der Aufzeichnungsschicht 3 befindet sich das bzw. befinden sich die zu entwickelnden elektrostatischen Ladungsbilder. Der Entwickler besteht bekannterweise aus Toner und Trägerteilchen. Letztere sind im allgemeinen magnetisch. Die elektrostatischen Ladungsbilder ziehen den Toner an, der auf diesen haftet und die Ladungsbilder zu Pulverbildern entwickelt. Die Trägerteilchen werden durch die fotoleitfähige Aufzeichnungsschicht 3 aus dem Entwickelbereich ausgetragen und durch einen nach der Entwicklungsvorrichtung 1 angeordneten Magnetabstreifer 25 von der fotoleitfähigen Aufzeichnungsschicht 3 abgezogen. Die Magnetbürstenwalze 4 rotiert in gleicher Drehrichtung wie die Trommel 2, die sich in Richtung des Pfeils P' dreht und trägt an ihrer Oberfläche einen Entwicklerpelz 5, der durch eine Rakel 6 abgestreift wird, die in Fig. 1 horizontal verlaufend dargestellt ist, jedoch auch in beliebig anderer Richtung zu der Oberfläche der Magnetbürstenwalze 4 geneigt sein kann.A magnetic brush developing device 1 shown in FIG. 1 for an electrostatic copying machine is adjacent to a drum 2, the surface of which is provided with a photoconductive recording layer 3 and which rotates in the direction of the arrow P. The or the electrostatic charge images to be developed are located on the recording layer 3. The developer is known to consist of toner and carrier particles. The latter are generally magnetic. The electrostatic charge images attract the toner that adheres to them and develops the charge images into powder images. The carrier particles are discharged from the development area through the photoconductive recording layer 3 and are removed from the photoconductive recording layer 3 by a magnetic stripper 25 arranged after the developing device 1. The magnetic brush roller 4 rotates in the same direction of rotation as the drum 2, which rotates in the direction of the arrow P 'and carries on its surface a developer fur 5, which is wiped off by a doctor blade 6, which is shown horizontally in FIG. 1, but also can be inclined to the surface of the magnetic brush roller 4 in any other direction.

Neben der Rakel 6 sind zwei elastische Abstreifer 7', 7", wie aus Fig. 2 ersichtlich ist, angeordnet, die an der fotoleitfähigen Aufzeichnungsschicht 3 anliegen und die Trägerteilchen 12 von dieser abstreifen. Die beiden Abstreifer 7', 7" bestehen aus nichtmagnetischem, elastischem Material und liegen an der fotoleitfähigen Aufzeichnungsschicht 3 so an, dass sie einen Winkel zwischen 5° bis 10° mit der Tangente t an die Aufzeichnungsschicht im Berührungspunkt der Abstreifer einschliessen. Die Abstreifer 7', 7" schliessen mit der Rakel 6 einen Winkel zwischen 45° bis 90° ein.In addition to the doctor blade 6, two elastic wipers 7 ', 7 "are arranged, as can be seen in FIG. 2, which abut the photoconductive recording layer 3 and wipe the carrier particles 12 off the latter. The two wipers 7', 7" consist of non-magnetic , elastic material and are in contact with the photoconductive recording layer 3 so that they enclose an angle between 5 ° to 10 ° with the tangent t to the recording layer at the point of contact of the wipers. The wipers 7 ', 7 "form an angle between 45 ° and 90 ° with the doctor blade 6.

Der Vorratsbehälter 15 für den Entwicklervorrat 11 weist einen umgebogenen Rand 13 auf, auf dem mittels einer Schraube 9 die Rakel 6 und die Abstreifer 7', 7" befestigt sind. Hierzu ist jeder Abstreifer 7', 7" von zwei gewinkelten Blechen 8, 8' eingefasst, von denen das untere Blech auf der Rakel 6 aufliegt. Im Rand 13 ist ein Langloch 26 vorhanden, so dass es möglich ist, die Schraube 9 im Langloch zu verschieben und dadurch den Abstand der Rakel 6 von der Oberfläche der Magnetbürstenwalze 4 zu verändern.The storage container 15 for the developer supply 11 has a bent edge 13, on which the squeegee 6 and the wipers 7 ', 7 "are fastened by means of a screw 9. For this purpose, each wiper 7', 7" is made of two angled sheets 8, 8 'edged, of which the lower plate rests on the squeegee 6. In the edge 13 there is an elongated hole 26 so that it is possible to move the screw 9 in the elongated hole and thereby to change the distance of the doctor blade 6 from the surface of the magnetic brush roller 4.

Wie aus Fig. 2 ersichtlich, ist die Oberfläche der Zylinderhülse 18 der Magnetbürstenwalze 4 mit Riefen 14 versehen, die die Ausbildung des Entwicklerpelzes 5 begünstigen. Die Rakel 6 besitzt eine linke Übergangszone 6' und eine rechte Übergangszone 6", das sind jeweils die Bereiche nahe der Stirnflächen 18', 18" der Zylinderhülse 18. In den Übergangszonen 6', 6" verläuft die Abstreifkante 27 der Rakel 6 nach unten gekrümmt. Die Abstreifer 7', 7" sind in Fig. 2 schraffiert, um anzudeuten, dass sie sich nicht in der gleichen Ebene wie die Rakel 6 befinden, sondern hinter dieser liegen. In der Draufsicht von den Abstreifern 7', 7" in Richtung der Rakel 6 überdeckt jeder Abstreifer 7', 7" eine der Übergangszonen 6' bzw. 6" der Rakel 6 nach aussen und nach innen, wobei die Überdeckung nach innen in Richtung Rakel - Mittellinie 24 zumindest 4 mm beträgt, während die Überdeckung nach aussen im allgemeinen 10 mm oder grösser ist. Bei einer praktischen Ausführungsform weist beispielsweise ein Abstreifer die Abmessungen 18 mm x 2 mm auf und ist 30 mm breit. Die elastischen Abstreifer 7', 7" verhindern den Austrag an Trägerteilchen 12 von der fotoleitfähigen Aufzeichnungsschicht 3 im Bereich der Rakelübergangszonen 6', 6", so dass die abgestreiften Trägerteilchen von dem Magnetfeld der Magnetbürstonwalze 4 mit Leichtigkeit angezogen werden können. Dadurch bleiben unterhalb der Abstreifer 7', 7" keine Trägerteilchen liegen, vielmehr werden diese vollständig in den Entwicklerkreislauf wieder zurückgeführt. Die elastischen Abstreifer 7', 7" machen daher einen rotierenden Abstreifer, wie er bei bekannten Einrichtungen zum Teil verwendet wird, nicht notwendig. Dadurch, dass der aus der Entwicklungsstation ausgetragene Entwickler durch die Abstreifer mengenmässig stark vermindert wird, muss ein der Entwicklungsstation nachgeschalteter Magnetabstreifer 25 für die Tonerteilchen nur noch sehr selten geleert werden.As can be seen from FIG. 2, the surface of the cylinder sleeve 18 of the magnetic brush roller 4 is provided with grooves 14 which promote the development of the developer fur 5. The doctor blade 6 has a left transition zone 6 'and a right transition zone 6 ", these are the regions near the end faces 18', 18" of the cylinder sleeve 18. In the transition zones 6 ', 6 ", the wiping edge 27 of the doctor blade 6 extends downward The wipers 7 ', 7 "are hatched in FIG. 2 to indicate that they are not in the same plane as the doctor blade 6, but are behind it. In the top view of the wipers 7 ', 7 "in the direction of the doctor blade 6, each wiper 7', 7" covers one of the transition zones 6 'and 6 "of the doctor blade 6 outwards and inwards, the overlap inwards in the direction of the doctor blade The center line 24 is at least 4 mm, while the overlap is generally 10 mm or larger in the outside. In a practical embodiment, for example, a wiper has the dimensions 18 mm x 2 mm and is 30 mm wide. The elastic wipers 7 ', 7 "prevent the discharge of carrier particles 12 from the photoconductive recording layer 3 in the area of the doctor blade transition zones 6 ', 6", so that the stripped carrier particles can be attracted by the magnetic field of the magnetic brush roller 4 with ease. As a result, none remain below the strippers 7', 7 " Carrier particles lie, rather they are completely returned to the developer cycle. The elastic wipers 7 ', 7 "therefore do not require a rotating wiper, such as is used in part in known devices. Because the developer discharged from the development station is greatly reduced in quantity by the wipers, a magnetic wiper downstream of the development station must be used 25 are very rarely emptied for the toner particles.

Aus Fig. 3 ist der Aufbau der Magnetbürstenwalze 4 ersichtlich, die innerhalb der Zylinderhülse 18 Magnete 17 zur Erzeugung des erforderlichen Magnetfeldes für den Entwicklerpelz aufweist.3 shows the structure of the magnetic brush roller 4, which has magnets 17 within the cylinder sleeve 18 for generating the required magnetic field for the developer fur.

Eine Abdeckung 20 schliesst die Entwicklungsvorrichtung nach oben zu ab, während ein Seitenteil 16 den Vorratsbehälter 15 umgibt. Zwischen dem Seitenteil 16 und der Abdeckung 20 ist eine Öffnung vorgesehen, in deren Bereich die Magnetbürstenwalze 4 nahe der fotoleitfähigen Aufzeichnungsschicht 3 angeordnet ist. Der Seitenteil 16 ist mit einer Grundplatte 22 verbunden, die mittels Schrauben an einem Rahmen 23 befestigt ist. Hinter der Magnetbürstenwalze 4 befindet sich ein Sammler 19, dessen Abstreifblech 21 tangential zu der Oberfläche der Zylinderhülse 18 der Magnetbürstenwalze 4 verläuft, um den nicht gezeigten Entwicklerpelz von deren Oberfläche abzustreifen. Von dem Sammler 19 gelangt der abgestreifte Entwickler in eine Umwälzvorrichtung 28, beispielsweise eine Förderschnecke, die den Entwickler umwälzt.A cover 20 closes off the developing device from above, while a side part 16 surrounds the storage container 15. An opening is provided between the side part 16 and the cover 20, in the area of which the magnetic brush roller 4 is arranged close to the photoconductive recording layer 3. The side part 16 is connected to a base plate 22 which is fastened to a frame 23 by means of screws. Behind the magnetic brush roller 4 there is a collector 19, the stripping plate 21 of which runs tangentially to the surface of the cylinder sleeve 18 of the magnetic brush roller 4 in order to strip the developer fur, not shown, from its surface. The stripped developer passes from the collector 19 into a circulating device 28, for example a screw conveyor, which circulates the developer.

Die Anordnung der Rakel 6 und der Abstreifer 7', 7" ist ähnlich zu derjenigen in Fig. 1 und wird daher nicht nochmals beschrieben.The arrangement of the doctor blade 6 and the wipers 7 ', 7 "is similar to that in FIG. 1 and is therefore not described again.

Claims (6)

1. Magnetic brush developing device for developing electrostatic charge images oin a photoconductive recording layer, in which device a developer consisting of a toner and of magnetic carrier particles is applied to the charge images, to which the toner adheres, and which has a doctor blade which bears against the magnetic brush roller, meters the quantity of carrier particles introduced by the magnetic brush roller and, at the ends of the roller, is taken to the end faces of the roller, wherein next to the doctor blade (6) two elastic wipers (7', 7") are provided which consist of a non-magnetic material and bear against the photoconductive recording layer (3) and wipe the carrier particles from the latter and wherein one wiper limiting the width of the developer applied by the magnetic brush roller (4) is arranged in both the region of a left-hand transition zone (6') and in the region of a right-hand transition zone (6") of the doctor blade (6), as viewed from above from the wipers in the direction of the doctor blade.
2. Magnetic brush developing device as claimed in claim 1, wherein each wiper (7', 7") extends both outwardly and inwardly of the transition zones (6', 6") of the doctor blade (6), with the inward coverage in the direction of the centerline (24) of the doctor blade being at least 4 mm.
3. Magnetic brush developing device as claimed in claims 1 and 2, wherein the doctor blade (6) bears horizontally against the magnetic brush roller (4) and the surfaces of the two wipers (7', 7") in elastic contact with the photoconductive recording layer (3) enclose an angle of 5° to 10° with the tangent (t) to the recording layer (3).
4. Magnetic brush developing device as claimed in any of claims 1 to 3, wherein the wipers (7', 7") and the doctor blade (6) are arranged with an inclination towards each other.
5. Magnetic brush developing device as claimed in claim 4, wherein the angle betwen the wipers (7', 7") and the doctor blade is 45° to 80°.
6. Magnetic brush developing device as claimed in any of claims 1 to 5, wherein each wiper (7',7") is held by two angled metal sheets (8, 8"), of which the lower metal sheet rests on the doctor blade (6), and the two metal sheets (8, 8') and the doctor blade (6) are adjustable joined by means of a fixing element (9) to one edge (13) of the stock vessel (15) for developer.
EP79102655A 1978-08-04 1979-07-26 Magnetic brush development apparatus for electrostatic charge images Expired EP0008040B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79102655T ATE235T1 (en) 1978-08-04 1979-07-26 MAGNETIC BRUSH DEVELOPMENT DEVICE FOR ELECTROSTATIC CHARGE IMAGES.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19782834264 DE2834264A1 (en) 1978-08-04 1978-08-04 MAGNETIC BRUSH DEVELOPMENT DEVICE FOR ELECTROSTATIC LOADING IMAGES
DE2834264 1978-08-04

Publications (2)

Publication Number Publication Date
EP0008040A1 EP0008040A1 (en) 1980-02-20
EP0008040B1 true EP0008040B1 (en) 1981-09-16

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EP79102655A Expired EP0008040B1 (en) 1978-08-04 1979-07-26 Magnetic brush development apparatus for electrostatic charge images

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US (1) US4261289A (en)
EP (1) EP0008040B1 (en)
JP (1) JPS5522792A (en)
AT (1) ATE235T1 (en)
CA (1) CA1132341A (en)
DE (2) DE2834264A1 (en)

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Publication number Priority date Publication date Assignee Title
JPS5648876B2 (en) * 1973-06-13 1981-11-18
JPH07107617B2 (en) * 1985-04-18 1995-11-15 富士ゼロックス株式会社 Electronic copier developing device
JPH0648404B2 (en) * 1986-06-12 1994-06-22 コニカ株式会社 Development device
JPH11272107A (en) * 1998-03-19 1999-10-08 Canon Inc Applying amount regulating body, fixing device and image forming device provided with it
EP1623281A2 (en) * 2003-03-27 2006-02-08 Eastman Kodak Company Method and system for wide format toning
BR112016008189B1 (en) 2013-10-23 2021-07-27 Prysmian S.P.A. POWER CABLE, AND, METHOD FOR EXTRACTING RETICULATED BY-PRODUCTS FROM A RETICULATED ELECTRICALLY INSULATING LAYER
ES2885682T3 (en) 2015-01-21 2021-12-15 Prysmian Spa Accessory for high voltage direct current power cables
WO2016170391A1 (en) 2015-04-22 2016-10-27 Prysmian S.P.A. Energy cable having a crosslinked electrically insulating system, and method for extracting crosslinking by-products therefrom

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Publication number Priority date Publication date Assignee Title
US3081737A (en) * 1961-03-01 1963-03-19 Gen Aniline & Film Corp Xerographic apparatus for applying ferromagnetic powder
US3866575A (en) * 1971-09-06 1975-02-18 Canon Kk Magnet roll developing device
US3884571A (en) * 1972-05-05 1975-05-20 Adalbert A Lux Leakage developer recirculation assembly
US4040387A (en) * 1972-09-24 1977-08-09 Mita Industrial Co. Ltd. Electrostatic photographic copying apparatus
US3918808A (en) * 1972-12-21 1975-11-11 Ricoh Kk Photoreceptor cleaning device for electrophotographic copying apparatus of the dry cleaning agent type
US3982498A (en) * 1973-11-19 1976-09-28 Xerox Corporation Development apparatus
US3999514A (en) * 1975-09-29 1976-12-28 International Business Machines Corporation Magnetic brush developer
JPS6044653B2 (en) * 1976-05-17 1985-10-04 株式会社リコー Developing bias automatic control method and device

Also Published As

Publication number Publication date
DE2960834D1 (en) 1981-12-03
CA1132341A (en) 1982-09-28
EP0008040A1 (en) 1980-02-20
DE2834264A1 (en) 1980-02-21
ATE235T1 (en) 1981-10-15
JPS5522792A (en) 1980-02-18
JPH0124308B2 (en) 1989-05-11
US4261289A (en) 1981-04-14

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