EP0000136A1 - Device for measuring the toner concentration in a development mixture - Google Patents

Device for measuring the toner concentration in a development mixture Download PDF

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Publication number
EP0000136A1
EP0000136A1 EP78100137A EP78100137A EP0000136A1 EP 0000136 A1 EP0000136 A1 EP 0000136A1 EP 78100137 A EP78100137 A EP 78100137A EP 78100137 A EP78100137 A EP 78100137A EP 0000136 A1 EP0000136 A1 EP 0000136A1
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EP
European Patent Office
Prior art keywords
component
coils
developer mixture
coil
plate
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Granted
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EP78100137A
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German (de)
French (fr)
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EP0000136B1 (en
Inventor
Peter Prohaska
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Hoechst AG
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Hoechst AG
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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
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0848—Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
    • G03G15/0849—Detection or control means for the developer concentration
    • G03G15/0853—Detection or control means for the developer concentration the concentration being measured by magnetic means
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S222/00—Dispensing
    • Y10S222/01—Xerography

Definitions

  • the invention relates to a device for measuring the toner concentration of a developer mixture of toner and ferromagnetic carrier material in an electrophotographic development device, with a component which is part of a measuring oscillator and carries an inductance, in the area of which at least part of the developer mixture arrives, the change in the toner concentration measured becomes.
  • DE-OS 2 014 430 a device of the type described at the outset for monitoring and controlling the con concentration of a toner in a developer mixture known; in the case of samples of the developer mixture being guided past the turns of a coil which is arranged in a circuit carrying alternating voltage, the output signals of which depend on the inductance of the coil and thus the toner concentration in the samples of the developer mixture and on which a circuit coupled to the alternating voltage is coupled, arrangement responsive to the output signals is provided for determining the toner concentration.
  • the arrangement for passing the sample of the developer mixture to the windings of the coil is a leading through the coil sample tube from UNMA g- netischem material.
  • the monitoring system for the toner concentration described in DT-CS 2 525 952 is constructed in a developer, which has a channel with an inlet and an outlet opening for the developer to be supplied, with a measuring coil at least partially surrounding the channel and with measuring devices for measuring the inductance changes in the measuring coil as a measure of the change in the toner concentration in the developer.
  • DT-OS 1 936 815 relates to a device for measuring the toner concentration of a developer mixture which consists of a coil with a ferromagnetic core which, together with part of the developer mixture, forms a magnetic circuit of the coil.
  • the coil and its magnetic circuit form an inductance, the change of which changes Output frequency of an oscillating circuit is influenced, so that any change in the permeability of the developer mixture results in a frequency change.
  • the core of the coil lies against the outside of the wall of the developer container, which at least in this area must consist of a non-magnetic material, so that the magnetic field can penetrate through the wall into the developer container and the magnetic circuit of the coil is above it Closes part of the developer mixture that lies opposite the core.
  • the leakage inductances used partly extend into the area of the developer mixture and that only samples of the developer mixture are detected. These are statistical measurements in which it is not certain whether the measured value is representative of the mean value of the toner concentration in the developer mixture.
  • a further disadvantage is that the coils used have a certain overall height, which allows installation only at certain points on the copying machine, and that the small inner diameter of the coils or the tubes which are passed through the coils give rise to blockages with developer mixture which makes frequent cleaning necessary.
  • the object of the invention is to improve a device according to the preamble of claim l's so that a component with an inductance is created is adapted to the tightest spaces in the copier and which can be arranged directly in the developer mixture which flows back from the photoconductive layer into the developer container in order to be able to determine a representative mean value of the toner concentration with great accuracy.
  • the component has at least one circuit board-shaped coil, all of whose conductor tracks lie in one plane.
  • the advantages are achieved that the measuring coils used in the measuring device have a very low overall height, which means that there are no difficulties when installing them in a copier, in which generally little space is available, and that the developer flow through the measuring coils largely remains undisturbed, e.g. does not experience a narrowing, and for the most part is detected.
  • Fig. 1 of the drawing shows a schematic view of a developing device 1 and a drum 2 of a copying machine.
  • the drum 2 is provided with a photoconductive surface and rotates, for example, in the direction of the arrow B.
  • On the photoconductive surface of the drum 2 there is an electrostatic latent image which is brought into contact with the developer mixture in the developing device 1 in order to bring it into contact develop visible toner image.
  • the developer mixture 7 is removed from a supply of developer 8 in a developer tank 14 by means of a so-called magnetic brush and applied to the surface of the drum 2.
  • the magnetic brush consists of a cylinder 3, which is rotatable about its longitudinal axis 37.
  • a plurality of magnets 15, 16, 17, 18 are arranged radially in the interior of the cylinder 3, of which, for example, the magnets 16, 17 for Conveying the developer mixture 7 and the magnet 15 serve to apply the developer mixture 7 to the drum 2.
  • the cylinder 3 immersed about half way into the developer reservoir 8 and the developer mixture of toner and carrier particles is applied to the magnets 16,17 Benach - pulled disclosed surface of the cylinder 3 and for developing the latent image on the surface of the drum 2 by the Rotation of the cylinder 3 promoted.
  • the ferromagnetic carrier particles align themselves in the direction of the lines of force of the magnetic field and, together with the toner, form a brush-like coating made of developer mixture on the surface of the cylinder 3.
  • a doctor blade 35 is used to limit the thickness of this coating attached to the right end edge of the developer tub 14 at a predetermined distance from the surface of the cylinder.3.
  • the magnets 15 to 18 are preferably bar magnets, the poles of which lie near the inside of the cylinder jacket have alternating polarity. The magnet 18 serves to keep the developer mixture 7 aligned after the contact between the cylinder 3 and the drum 2 like a magnetic brush.
  • the developing device 1 is fastened on a support frame 9 which is arranged on a console 36.
  • a cover 12 closes the developing device 1 upwards.
  • a mixer shaft 10, which rotates about its longitudinal axis 38, is provided near the bottom of the developer tub 14 and ensures appropriate mixing of the developer supply 8 in the developer tub 14.
  • the developing device 1 is connected in an integrated design to a suction housing 13 of a suction 11, which adjoins the developer tub 14 and ensures that free-floating developer mixture is sucked outside the developer tub 14.
  • the developer mixture 7 which is not applied to the surface of the drum 2 reaches a deflector plate 4 which runs obliquely and tangentially to the surface of the cylinder 3.
  • the baffle 4 is attached to a mounting bracket 19 and can be, for example, over its width, i.e. perpendicular to the plane of the drawing, be sawtooth-like, wherein the tips of the saw teeth 4 'can be bent up.
  • the developer mixture 7 trickles through the baffle 4 into the developer tank 14 back to the developer supply 8.
  • a component 5 is arranged, which consists at least of a plate-shaped coil 6.
  • the lower end of the baffle plate 4 bears against a further fastening support 20, on which lateral boundaries of the baffle plate 4 are attached, which are not shown.
  • the component 5 with its inductance given by the coil 6 is part of a circuit for determining changes in the inductance of the coil 6 as a function of changes in the concentration of the toner in the developer mixture 7, the circuit also generating signals for actuating a toner supply device, not shown.
  • the component 5 is arranged such that at least part of the developer mixture 7, which trickles into the developer trough 14 via the deflector plate 4, reaches the area of the magnetic field lines of the coil 6.
  • the embodiment of the component 5 shown in FIG. 2a contains the single coil 6, which extends in a rectangular shape over the length of the component to close to the edges predetermined by the narrow sides of the component.
  • the component 5 is formed with the coil 6 as a circuit board on which the conductor tracks 22 of the coil 6 are obtained by etching the surface of an electrically conductive plate. This can be done, for example, in a known manner by coating the plate with a light-sensitive layer onto which a negative of the coil is copied. It is then developed and etched. The result is an overetch, i.e. the coil appears raised.
  • a metal foil, thin metal sheet or the like can also be used to produce the coil 6, which is then connected to the component 5.
  • a conductor track 22 similar to a spiral, leads to the outside with side edges 24, 25 which are perpendicular to one another.
  • the side edges 24, 25 become longer towards the outside.
  • the component 5 generally has a length which corresponds at least to the total width of the deflector plate 4.
  • the electrical connection of the coil 6 takes place on the one hand at the outer end of the conductor track 22 and on the other hand at a so-called via point of the central part 23, not shown.
  • the embodiment of a further component 21 shown in FIG. 2b has, in addition to the coil 6, a number of further board-shaped coils 6 ', 6 ",... Which are electrically connected to one another in series.
  • the design of the individual coils 6, 6', 6", .... is similar to that of the coil 6 described above of the component 5.
  • the conductor tracks 22 of these coils are in the form of non-closed rectangles, the individual conductor tracks starting from a central part 23 of each coil 6, 6 'or 6 ", Vietnamese and longer towards the outside will have side edges 24.25.
  • the connection of the individual coils 6, 6 'and 6', 6 "from the via point, not shown, of the central part 23 of the individual coil to the subsequent coil is shown partly in broken lines.
  • Fig. 2c. shows another embodiment of the component 21, which consists of a number of plate-shaped coils 6, 6 ', 6 ", ..., the conductor tracks 26 of which run spirally from the inside to the outside. These coils are also in Row electrically connected to each other.
  • the ladder tracks of the individual coils can also be performed differently as shown in the preferred exemplary embodiments, and that the manufacture of the individual coils can also be carried out by other etching processes or other processes, such as, for example, electroplating of the conductor tracks on the component.
  • 2d shows a further embodiment of the component 5 or 21, which has an inductance made up of a number of plate-shaped coils 6, 6 ', 6 ", ..., which are shown schematically in the drawing.
  • the shape corresponds to an individual coil one of the reference to Figs - coil forms described 2a to 2c..
  • the coils are arranged geometrically next to one another on both sides of a strip 39 and on each side. To avoid an electrically conductive contact between the developer mixture 7 and the coils, these are surrounded by a layer of electrically insulating, transparent material 27.
  • the strip 39 consists for example of a plastic film which is coated on both sides with copper. As already described above, the individual coils are etched out of the copper layer on each side of the strip 39.
  • the central one Part 23 of one of the coils 6, 6 ', 6 ", ... is electrically connected via a via point 40 to the corresponding, opposite coil 6, 6', 6", ... on the other side of the strip 39. As indicated schematically in FIG. 2d, the coils 6, 6 ', 6 ",...
  • the matrix 41 are connected together in a matrix 41 in such a way that the coils in a single row 42 of the matrix 41 are electrically connected to one another in series.
  • the rows on the other hand, the matrix 41 are electrically connected in parallel. If, for example, it is a square matrix, the total inductance of the matrix is equal to the inductance of the individual coil 6, 6 'or 6 ", etc.
  • a matrix has developed 25 coils, arranged in 5 rows of 5 coils, have proven their worth. Of course, you can also choose a matrix that is not square but rectangular.
  • the most varied combinations of series and parallel connections within the matrix are conceivable.
  • the geometrical arrangement of the coils on each side of the strip 39 takes place side by side, regardless of the electrical interconnection of the coils chosen in each case to form a specific matrix.
  • FIG. 3 shows a block diagram of the device for measuring the toner concentration of the developer mixture 7.
  • the component 5 or 21 is part of a measuring oscillator 34 , which is connected to a reference oscillator 28.
  • the two oscillators are controlled by a timer 30, which either switches the measuring oscillator 34 or the reference oscillator 28, so that only one frequency / voltage converter 29 the output frequency of one of the two oscillators.
  • the output voltage of converter 29 is amplified accordingly in an amplifier 31 and controls a Schmitt trigger stage 32. This is set such that a motor 33 connected to it is switched on when it is necessary to replenish the developer mixture with toner to be refilled, and is switched off when the developer mixture has the desired toner concentration.
  • the motor 33 actuates a toner supply device, not shown.
  • the circuit structure of the measuring oscillator 34 is known per se and comprises an oscillating circuit, formed from a capacitor and the inductance of the component 5 or 21.
  • This oscillating circuit is arranged in the collector path of a transistor, the base of which is connected to a voltage source.
  • the transistor is part of an oscillator circuit which has a further transistor.
  • the emitters of the two transistors are connected to the collector of a further transistor which works as a switching transistor and is opened or closed by the timer 30.
  • Each change in the leakage inductance of the individual coil 6 or the combination of coils 6, 6 ', 6 ", ... of the component 5 or 21 changes the frequency of the measuring oscillator 34.
  • the output frequency of the measuring oscillator 34 becomes the fixed output frequency of the reference oscillator 28.
  • the setting is such that as the toner concentration in the developer mixture decreases, the resonance frequency of the measuring oscillator 34 increases and thus the deviation of this frequency from the fixed reference frequency of the reference oscillator 28 increases upwards.
  • the motor 33 is then started up in accordance with the selected degree of amplification of the amplifier 31 and the trigger voltage for the Schmitt trigger stage 32. As long as the output frequency of the measuring oscillator 34 is below the value of the fixed frequency of the reference oscillator 28, the Schmitt trigger stage 32 does not respond and the motor 33 stands still, so that no toner is supplied to the developer mixture.

Abstract

Die Erfindung betrifft eine Vorrichtung zur Messung der Tonerkonzentration eines Entwicklergemisches. Ein Bauteil (5;21) trägt zumindest eine platinenförmige Spule (6) bzw. eine Anzahl von platinenförmigen Spulen (6,6',6",...), deren sämtliche Leiterbahnen (22) in einer Ebene liegen. Die Spule bzw. die Spulen des Bauteils bilden die Induktivität eines Meßoszillators (34) und sind im Entwicklergemisch-Strom angeordnet, der von der fotoleitfähigen Oberfläche einer Trommel (2) herabrieselt, auf der ein latentes Ladungsbild mit dem Entwicklergemisch in ein Pulverbild entwickelt wird. Die Leiterbahen der Spulen sind rechteckoder spiralförmig angeordnet und können mit einem elektrisch isolierenden, transparenten Material (27) vergossen sein. Die Spulen sind des weiteren in einer Matrix (41) elektrisch zusammengeschaltet und auf beiden Seiten eines auf dem Bauteil (21) befestigten Streifens (39) angeordnet.The invention relates to a device for measuring the toner concentration of a developer mixture. A component (5; 21) carries at least one plate - shaped coil (6) or a number of plate - shaped coils (6, 6 ', 6 ", ...), all of whose conductor tracks (22) lie in one plane The coils of the component form the inductance of a measuring oscillator (34) and are arranged in the developer mixture current, which trickles down from the photoconductive surface of a drum (2), on which a latent charge image with the developer mixture is developed into a powder image Coils are arranged in a rectangular or spiral shape and can be cast with an electrically insulating, transparent material (27) .The coils are also electrically interconnected in a matrix (41) and arranged on both sides of a strip (39) attached to the component (21) .

Description

Die Erfindung betrifft eine Vorrichtung zur Messung der Tonerkonzentration eines Entwicklergemisches aus Toner und ferromagnetischem Trägermaterial in einer elektrofotografischen Entwicklungsvorrichtung, mit einem Bauteil, das Bestandteil eines Meßoszillators ist und eine Induktivität trägt, in deren Bereich zumindest ein Teil des Entwicklergemisches gelangt, dessen Änderung der Tonerkonzentration gemessen wird.The invention relates to a device for measuring the toner concentration of a developer mixture of toner and ferromagnetic carrier material in an electrophotographic development device, with a component which is part of a measuring oscillator and carries an inductance, in the area of which at least part of the developer mixture arrives, the change in the toner concentration measured becomes.

Bei den bekannten Kopiergeräten, bei denen die latenten elektrostatischen Bilder auf der Oberfläche einer fotoleitfähigen Schicht mit Hilfe eines Entwicklergemisches aus Toner und ferromagnetischem Trägermaterial entwickelt werden, verbrauchen sich nur die Tonerpartikeln, während das ferromagnetische Trägermaterial zurückbleibt und wiederverwendet werden kann. Es ist daher erforderlich, das Entwicklergemisch periodisch oder kontinuierlich durch die Ergänzung des verbrauchten Toners aufzufrischen, um die Konzentration des Toners in dem Entwicklergemisch zum Erzielen einer gewünschten Dichte der entwickelten Kopien auf einem vorgegebenen Wert innerhalb enger Grenzen zu halten. Wenn die Tonerkonzentration in dem Entwicklergemisch kleiner als die optimale Konzentration ist, wird die Schwärzung der entwickelten Kopie zu gering, und wenn andererseits die Tonerkonzentration zu groß ist, ergeben sich Kopien mit einem unerwünschten Untergrund.In the known copying machines, in which the latent electrostatic images on the surface of a photoconductive layer are developed with the aid of a developer mixture of toner and ferromagnetic carrier material, only the toner particles are consumed, while the ferromagnetic carrier material remains behind and can be reused. It is therefore necessary to refresh the developer mixture periodically or continuously by adding the used toner in order to keep the concentration of the toner in the developer mixture to a predetermined value within narrow limits in order to achieve a desired density of the developed copies. If the toner concentration in the developer mixture is less than the optimal concentration, the density of the developed copy becomes too low, and if the toner concentration is too high, copies with an undesirable background result.

Aus der DE-OS 2 014 430 ist eine Vorrichtung der eingangs beschriebenen Art zur Überwachung und Regelung der Konzentration eines Toners in einer Entwicklermischung bekannt; bei der Proben der Entwicklermischung an den Windungen einer Spule vorbeigeführt werden, die in einem Wechselspannung führenden Kreis angeordnet ist, dessen Ausgangssignale von der Induktivität der Spule und damit der Tonerkonzentration in den Proben der Entwicklermischung abhängen und bei der eine mit dem Wechselspannung führenden Kreis gekoppelte, auf die Ausgangssignale ansprechende Anordnung zur Bestimmung der Tonerkonzentration vorgesehen ist. Die Anordnung zum Vorbeiführen der Proben der Entwicklermischung an den Windungen der Spule ist eine durch die Spule führende Probenröhre aus unmag- netischem Material.From DE-OS 2 014 430 a device of the type described at the outset for monitoring and controlling the con concentration of a toner in a developer mixture known; in the case of samples of the developer mixture being guided past the turns of a coil which is arranged in a circuit carrying alternating voltage, the output signals of which depend on the inductance of the coil and thus the toner concentration in the samples of the developer mixture and on which a circuit coupled to the alternating voltage is coupled, arrangement responsive to the output signals is provided for determining the toner concentration. The arrangement for passing the sample of the developer mixture to the windings of the coil is a leading through the coil sample tube from UNMA g- netischem material.

In ähnlicher Weise ist das in der DT-CS 2 525 952 beschriebene Überwachungssystem für die Tonerkonzentration in einem Entwickler aufgebaut, das einen Kanal mit einer Einlaß- und einer Auslaßöffnung für den zuzuführenden Entwickler aufweist, wobei eine Meßspule den Kanal zumindest teilweise umgibt und mit Meßeinrichtungen zum Messen der Induktivitätsänderungen in der Meßspule als Maß für die Änderung der Tonerkonzentration in dem Entwickler verbunden ist.Similarly, the monitoring system for the toner concentration described in DT-CS 2 525 952 is constructed in a developer, which has a channel with an inlet and an outlet opening for the developer to be supplied, with a measuring coil at least partially surrounding the channel and with measuring devices for measuring the inductance changes in the measuring coil as a measure of the change in the toner concentration in the developer.

Die DT-OS 1 936 815.betrifft eine Vorrichtung zum Messen der Tonerkonzentration einer Entwicklermischung, die aus einer Spule mit einem ferromagnetischen Kern besteht, der zusammen mit einem Teil der Entwicklermischung einen mag- netischeri Kreis der Spule bildet. Die Spule und ihr m:igne- tischer Kreis bilden eine Induktivität, deren Änderung die Ausgangsfrequenz eines Schwingkreises beeinflußt, so daß jede Änderung der Permeabilität der Entwicklermischung eine Frequenzänderung zur Folge hat. Die Spule liegt mit ihrem Kern an der Außenseite der Wandung des Entwicklerbehälters an, der zumindest in diesem Bereich aus einem unmagnetischen Material bestehen muß, damit .das magnetische Feld durch die Wandung hindurch in den Entwicklerbehälter eindringen kann und der magnetische Kreis der Spule sich über denjenigen Teil der Entwicklermischung schließt, der dem Kern gegenüber liegt.DT-OS 1 936 815 relates to a device for measuring the toner concentration of a developer mixture which consists of a coil with a ferromagnetic core which, together with part of the developer mixture, forms a magnetic circuit of the coil. The coil and its magnetic circuit form an inductance, the change of which changes Output frequency of an oscillating circuit is influenced, so that any change in the permeability of the developer mixture results in a frequency change. The core of the coil lies against the outside of the wall of the developer container, which at least in this area must consist of a non-magnetic material, so that the magnetic field can penetrate through the wall into the developer container and the magnetic circuit of the coil is above it Closes part of the developer mixture that lies opposite the core.

Diesen bekannten Vorrichtungen zur Messung der Tonerkonzentration ist gemeinsam, daß die verwendeten Streuinduktivitäten zum Teil in den Bereich der Entwicklermischung hineinreichen und daß nur Proben der Entwicklermischung erfaßt werden. Dabei handelt es sich um-statistische Messungen, bei denen nicht sichergestellt ist, ob der Meßwert repräsentativ für den Mittelwert der Tonerkonzentration in dem Entwicklergemisch ist. Des weiteren ist von Nachteil, daß die verwendeten Spulen eine bestimmte Bauhöhe haben, die den Einbau nur an bestimmten Stellen des Kopiergerätes zuläßt und daß der geringe innere Durchmesser der Spulen bzw. der Rohre, die durch die Spulen hindurchgeführt werden, Anlaß zu Verstopfungen mit Entwicklergemisch sind, wodurch ein häufiges Reinigen erforderlich wird.Common to these known devices for measuring the toner concentration is that the leakage inductances used partly extend into the area of the developer mixture and that only samples of the developer mixture are detected. These are statistical measurements in which it is not certain whether the measured value is representative of the mean value of the toner concentration in the developer mixture. A further disadvantage is that the coils used have a certain overall height, which allows installation only at certain points on the copying machine, and that the small inner diameter of the coils or the tubes which are passed through the coils give rise to blockages with developer mixture which makes frequent cleaning necessary.

Aufgabe der Erfindung ist es, eine Vorrichtung nach dem Oberbegriff des Patentanspruchs l'so zu verbessern, daß ein Bauteil mit einer Induktivität geschaffen wird, die an engste Raumverhältnisse in dem Kopiergerät angepaßt ist und.die direkt in dem Entwicklergemisch, das von der fotoleitfähigen Schicht in den Entwicklerbehälter zurückströmt, angeordnet werden kann, um einen repräsentativen Mittelwert der Tonerkonzentration mit großer Genauigkeit bestimmen zu können.The object of the invention is to improve a device according to the preamble of claim l's so that a component with an inductance is created is adapted to the tightest spaces in the copier and which can be arranged directly in the developer mixture which flows back from the photoconductive layer into the developer container in order to be able to determine a representative mean value of the toner concentration with great accuracy.

Diese Aufgabe wird gemäß der Erfindung dadurch gelöst, daß das Bauteil zumindest eine platinenförmige Spule aufweist, deren sämtliche Leiterbahnen in einer Ebene liegen.This object is achieved according to the invention in that the component has at least one circuit board-shaped coil, all of whose conductor tracks lie in one plane.

Die Ausgestaltung der Erfindung ist aus den kennzeichnenden Merkmalen der Patentansprüche 2 bis 13ersichtlich.The embodiment of the invention can be seen from the characterizing features of claims 2 to 13.

Mit der Erfindung werden die Vorteile erzielt, daß die in der Meßvorrichtung verwendeten Meßspulen eine sehr geringe Bauhöhe besitzen, wodurch es keine Schwierigkeiten beim Einbau in ein Kopiergerät gibt, in welchem im allgemeinen wenig Platz zur Verfügung steht, und daß der Entwicklerstrom durch die Meßspulen weitgehend ungestört bleibt, z.B. keine Einengung erfährt, und zum größten Teil erfaßt wird.With the invention, the advantages are achieved that the measuring coils used in the measuring device have a very low overall height, which means that there are no difficulties when installing them in a copier, in which generally little space is available, and that the developer flow through the measuring coils largely remains undisturbed, e.g. does not experience a narrowing, and for the most part is detected.

Die Erfindung wird im folgenden anhand von zeichnerisch dargestellten Ausführungsbeispielen näher beschrieben. In den Zeichnungen zeigen:

  • Fig. 1 eine schematische Ansicht eines Teils eines Kopiergeräts, das eine Ausführungsform der Erfindung enthält,
  • Fig. 2a Bauteile mit einer Induktivität, die Be-und 2b standteileder Vorrichtung zur Messung der Tonerkonzentration im Entwicklergemisch sind,
  • Fig. 2c weitere Bauteile mit jeweils einer Induktivi-und 2d tät, die Bestandteile der Vorrichtung zur Messung der Tonerkonzentration im Entwicklergemisch sind, und
  • Fig. 3 ein Blockschaltbild der Vorrichtung zur Messung der Tonerkonzentration des Entwicklergemisches.
The invention is described in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show:
  • 1 is a schematic view of part of a copying machine incorporating an embodiment of the invention;
  • 2a components with an inductance, which are components of the device for measuring the toner concentration in the developer mixture,
  • 2c further components, each with an inductive and 2d act , which are components of the device for measuring the toner concentration in the developer mixture, and
  • Fig. 3 is a block diagram of the device for measuring the toner concentration of the developer mixture.

Fig. 1 der Zeichnung zeigt in schematischer Ansicht eine Entwicklungsvorrichtung 1 und eine Trommel 2 eines Kopiergerätes. Die Trommel 2 ist mit einer fotoleitenden Oberfläche versehen und dreht sich beispielsweise in Richtung des Pfeils B. Auf der fotoleitenden Oberfläche der Trommel 2 befindet sich ein elektrostatisches latentes Bild, das in der Entwicklungsvorrichtung 1 mit dem Entwicklergemisch in Berührung gebracht wird, um es in ein sichtbares Tonerbild zu entwickeln.Fig. 1 of the drawing shows a schematic view of a developing device 1 and a drum 2 of a copying machine. The drum 2 is provided with a photoconductive surface and rotates, for example, in the direction of the arrow B. On the photoconductive surface of the drum 2 there is an electrostatic latent image which is brought into contact with the developer mixture in the developing device 1 in order to bring it into contact develop visible toner image.

Das Entwicklergemisch 7 wird mittels einer sogenannten Magnetbürste einem Ehtwicklervorrat 8 in einer Entwicklerwanne 14 entnommen und an die Oberfläche der Trommel 2 angetragen. Die Magnetbürste besteht aus einem Zylinder 3, der um seine Längsachse 37 drehbar ist. Im Inneren des Zylinders 3 sind mehrere Magnete 15,16,17,18 radial angeordnet, von denen beispielsweise die Magnete 16,17 zum Fördern des Entwicklergemisches 7 und der Magnet 15 dem Antragen des Entwicklergemisches 7 an die Trommel 2 dienen. Der Zylinder 3 taucht etwa zur Hälfte in den Entwicklervorrat 8 ein und das Entwicklergemisch aus Toner-und Trägerteilchen wird an die den Magneten 16,17 benach- barte Oberfläche des Zylinders 3 gezogen und zur Entwicklung des latenten Bildes auf der Oberfläche der Trommel 2 durch die Drehung des Zylinders 3 gefördert. Unter dem Einfluß des Magnetfeldes der Magneten 15 bis 18 richten sich die ferromagnetischen Trägerteilchen in Richtung der Kraftlinien des Magnetfeldes aus und bilden zusammen mit dem Toner einen bürstenähnlichen Belag aus Entwicklergemisch auf der Oberfläche des Zylinders 3. Zur Begrenzung der Dicke dieses Belages ist eine Abstreifrakel 35 an der rechten Abschlußkante der Entwicklerwanne 14 in einem vorgegebenen Abstand von der Oberfläche des Zylinders.3 befestigt. Bei den Magneten 15 bis 18.handelt es sich bevorzugt um Stabmagnete, deren nahe der Innenseite des Zylindermantels liegenden Pole abwechselnde Polarität aufweisen. Der Magnet 18 dient dazu, das Entwicklergemisch 7 nach dem Kontakt zwischen dem Zylinder 3 und der Trommel 2 weiterhin magnetbürstenartig ausgerichtet zu halten.The developer mixture 7 is removed from a supply of developer 8 in a developer tank 14 by means of a so-called magnetic brush and applied to the surface of the drum 2. The magnetic brush consists of a cylinder 3, which is rotatable about its longitudinal axis 37. A plurality of magnets 15, 16, 17, 18 are arranged radially in the interior of the cylinder 3, of which, for example, the magnets 16, 17 for Conveying the developer mixture 7 and the magnet 15 serve to apply the developer mixture 7 to the drum 2. The cylinder 3 immersed about half way into the developer reservoir 8 and the developer mixture of toner and carrier particles is applied to the magnets 16,17 Benach - pulled disclosed surface of the cylinder 3 and for developing the latent image on the surface of the drum 2 by the Rotation of the cylinder 3 promoted. Under the influence of the magnetic field of the magnets 15 to 18, the ferromagnetic carrier particles align themselves in the direction of the lines of force of the magnetic field and, together with the toner, form a brush-like coating made of developer mixture on the surface of the cylinder 3. A doctor blade 35 is used to limit the thickness of this coating attached to the right end edge of the developer tub 14 at a predetermined distance from the surface of the cylinder.3. The magnets 15 to 18 are preferably bar magnets, the poles of which lie near the inside of the cylinder jacket have alternating polarity. The magnet 18 serves to keep the developer mixture 7 aligned after the contact between the cylinder 3 and the drum 2 like a magnetic brush.

Die Entwicklungsvorrichtung 1 ist auf einem Stützrahmen 9 befestigt, der auf einer Konsole 36 angeordnet ist. Eine Abdeckung 12 schließt die Entwicklungsvorrichtung 1 nach oben hin ab. Nahe dem Boden der Entwicklerwanne 14 ist eine sich um ihre Längsachse 38 drehende Mischerwelle 10 vorgesehen, die für eine entsprechende Durchmischung des Entwicklervorrates 8 in der Entwicklerwanne 14 sorgt. Mit der Entwicklungsvorrichtung 1 ist in integrierter Bauweise ein Absauggehäuse 13 einer Absaugung 11 verbunden, die an die Entwicklerwanne 14 angrenzt.und dafür sorgt, daß außerhalb der Entwicklerwanne 14 freischwebendes Entwicklergemisch abgesaugt wird.The developing device 1 is fastened on a support frame 9 which is arranged on a console 36. A cover 12 closes the developing device 1 upwards. A mixer shaft 10, which rotates about its longitudinal axis 38, is provided near the bottom of the developer tub 14 and ensures appropriate mixing of the developer supply 8 in the developer tub 14. With The developing device 1 is connected in an integrated design to a suction housing 13 of a suction 11, which adjoins the developer tub 14 and ensures that free-floating developer mixture is sucked outside the developer tub 14.

Das nicht an die Oberfläche der Trommel 2 angetragene Entwicklergemisch 7 gelangt auf ein Ableitblech 4, das schräg und tangential zu der Oberfläche des Zylinders 3 verläuft. Das Ableitblech 4 ist auf einer Befestigungsstütze 19 angebracht und kann beispielsweise über seine Breite, d.h. senkrecht zu der Zeichnungsebene, sägezahnartig ausgebildet sein, wobei die Spitzen der Sägezähne 4' hochgeknickt sein können. Das Entwicklergemisch 7 rieselt über das Ableitblech 4 in die Entwicklerwanne 14 zu dem Entwicklervorrat 8 zurück. Im oberen Teil des Ableitbleches nahe dem Zylinder 3 der Magnetbürste ist ein Bauteil 5 angeordnet, das zumindest aus einer platinenförmigen Spule 6 besteht. Das untere Ende des Ableitbleches 4 liegt gegen eine weitere Befestigungsstütze 20 an, an der seitliche Begrenzungen des Ableitbleches 4 angebracht sind, die nicht dargestellt sind.The developer mixture 7 which is not applied to the surface of the drum 2 reaches a deflector plate 4 which runs obliquely and tangentially to the surface of the cylinder 3. The baffle 4 is attached to a mounting bracket 19 and can be, for example, over its width, i.e. perpendicular to the plane of the drawing, be sawtooth-like, wherein the tips of the saw teeth 4 'can be bent up. The developer mixture 7 trickles through the baffle 4 into the developer tank 14 back to the developer supply 8. In the upper part of the deflector near the cylinder 3 of the magnetic brush, a component 5 is arranged, which consists at least of a plate-shaped coil 6. The lower end of the baffle plate 4 bears against a further fastening support 20, on which lateral boundaries of the baffle plate 4 are attached, which are not shown.

Das Bauteil 5 mit seiner durch die Spule 6 gegebenen Induktivität ist Bestandteil einer Schaltung zum Feststellen von Änderungen der Induktivität der Spule 6 in Abhängigkeit von Änderungen der Konzentration des Toners in dem Entwicklergemisch 7, wobei die Schaltung auch Signale zur Betätigung einer nicht dargestellten Tonerzufuhreinrichtung erzeugt.The component 5 with its inductance given by the coil 6 is part of a circuit for determining changes in the inductance of the coil 6 as a function of changes in the concentration of the toner in the developer mixture 7, the circuit also generating signals for actuating a toner supply device, not shown.

Das Bauteil 5 ist derart angeordnet, daß zumindest ein Teil des Entwicklergemisches 7, das über das .Ableitblech 4 in die Entwicklerwanne 14 rieselt, in den Bereich der magnetischen Feldlinien der Spule 6 gelangt.The component 5 is arranged such that at least part of the developer mixture 7, which trickles into the developer trough 14 via the deflector plate 4, reaches the area of the magnetic field lines of the coil 6.

Die in Fig. 2a dargestellte Ausführung des Bauteils 5 enthält die einzige Spule 6, die sich rechteckformig über die Länge des Bauteils bis nahe an die durch die Schmalseiten des Bauteils vorgegebenen Ränder erstreckt. Das Bauteil 5 ist mit der Spule 6 als Platine ausgebildet, auf der die Leiterbahnen 22 der Spule 6 durch Ätzen der Oberfläche einer elektrisch leitenden Platte erhalten werden. Dies kann beispielsweise in bekannter Weise durch Überziehen der Platte mit einer lichtempfindlichen Schicht geschehen, auf die ein Negativ der Spule kopiert wird. Anschließend wird entwickelt und geätzt. Das Ergebnis ist eine Hochätzung, d.h. die Spule erscheint erhaben. Selbstverständlich kann anstelle einer Platte auch eine Metallfolie, dünnes Metallblech oder dgl. zur Herstellung der Spule 6 verwendet werden, die dann anschließend mit dem Bauteil 5 verbunden wird.The embodiment of the component 5 shown in FIG. 2a contains the single coil 6, which extends in a rectangular shape over the length of the component to close to the edges predetermined by the narrow sides of the component. The component 5 is formed with the coil 6 as a circuit board on which the conductor tracks 22 of the coil 6 are obtained by etching the surface of an electrically conductive plate. This can be done, for example, in a known manner by coating the plate with a light-sensitive layer onto which a negative of the coil is copied. It is then developed and etched. The result is an overetch, i.e. the coil appears raised. Of course, instead of a plate, a metal foil, thin metal sheet or the like can also be used to produce the coil 6, which is then connected to the component 5.

Ausgehend von einem zentralen Teil 23 der Spule 6 führt eine Leiterbahn 22, ähnlich einer Spirale, mit zueinander rechtwinkligen Seitenkanten 24,25 nach außen. Die Seitenkanten 24,25 werden nach außen hin länger. Das Bauteil 5 besitzt im allgemeinen eine Länge, die zumindest der Gesamtbreite des Ableitbleches 4 entspricht.Starting from a central part 23 of the coil 6, a conductor track 22, similar to a spiral, leads to the outside with side edges 24, 25 which are perpendicular to one another. The side edges 24, 25 become longer towards the outside. The component 5 generally has a length which corresponds at least to the total width of the deflector plate 4.

Der elektrische Anschluß der Spule 6 erfolgt einerseits an dem äußeren Ende der Leiterbahn 22 und andererseits an einer nicht dargestellten, sogenannten Durchkontaktierungsstelle des zentralen Teils 23.The electrical connection of the coil 6 takes place on the one hand at the outer end of the conductor track 22 and on the other hand at a so-called via point of the central part 23, not shown.

Die in Fig. 2b gezeigte Ausführungsform eines weiteren Bauteils 21 weist neben der Spule 6 noch eine Anzahl von weiteren platinenförmigen Spulen 6',6",.... auf, die in Reihe miteinander elektrisch verbunden sind.-Diese platinenförmigen Spulen 6,6',6" erstrecken sich nahezu wieder über die Gesamtlänge des Bauteils 21 und damit auch über die Gesamtbreite des Ableitbleches 4. Die Ausgestaltung der einzelnen Spulen 6,6',6",.... ist ähnlich zu derjenigen der voranstehend beschriebenen Spule 6 des Bauteils 5. Die Leiterbahnen 22 dieser Spulen weisen die Form von nicht geschlossenen Rechtecken auf, wobei die einzelnen Leiterbahnen von jeweils einem zentralen Teil 23 jeder Spule 6,6' bzw. 6", ..... ausgehen und nach außen hin länger werdende Seitenkanten 24,25 besitzen. Die Verbindung der einzelnen Spulen 6,6' bzw. 6',6" von der nicht dargestellten Durchkontaktierungsstelle des zentralen Teils 23 der einzelnen Spule zu der anschließenden Spule ist teilweise gestrichelt eingezeichnet.The embodiment of a further component 21 shown in FIG. 2b has, in addition to the coil 6, a number of further board-shaped coils 6 ', 6 ",... Which are electrically connected to one another in series. These board-shaped coils 6, 6 ', 6 "extend again almost over the entire length of the component 21 and thus also over the entire width of the deflector plate 4. The design of the individual coils 6, 6', 6", .... is similar to that of the coil 6 described above of the component 5. The conductor tracks 22 of these coils are in the form of non-closed rectangles, the individual conductor tracks starting from a central part 23 of each coil 6, 6 'or 6 ", ..... and longer towards the outside will have side edges 24.25. The connection of the individual coils 6, 6 'and 6', 6 "from the via point, not shown, of the central part 23 of the individual coil to the subsequent coil is shown partly in broken lines.

Fig.-2c.zeigt eine.weitere Ausführungsform des Bauteils 21, der aus einer Anzahl von platinenförmigen Spulen 6,6',6",.... besteht, deren Leiterbahnen 26 von innen nach außen spiralförmig verlaufen. Diese Spulen sind gleichfalls in Reihe miteinander elektrisch verbunden.Fig. 2c.shows another embodiment of the component 21, which consists of a number of plate-shaped coils 6, 6 ', 6 ", ..., the conductor tracks 26 of which run spirally from the inside to the outside. These coils are also in Row electrically connected to each other.

Für den Fachmann ist es selbstverständlich, daß die Leiterbahnen der einzelnen Spulen auch noch anders wie in den bevorzugten Ausführungsbeispielen dargestellt, geführt sein können.und daß die Herstellung der einzelnen Spulen auch nach anderen Ätzverfahren oder sonstigen Verfahren, wie beispielsweise Aufgalvanisieren der Leiterbahnen aif das Bauteil, erfolgen kann.It is obvious to a person skilled in the art that the ladder tracks of the individual coils can also be performed differently as shown in the preferred exemplary embodiments, and that the manufacture of the individual coils can also be carried out by other etching processes or other processes, such as, for example, electroplating of the conductor tracks on the component.

Zur Vermeidung einer elektrisch leitenden Berührung zwischen dem Entwicklergemisch 7 und den Leiterbahnen 22 bzw. 26 der platinenförmigen Spulen 6,6',6" der Bauteile 5 bzw. 21 sind diese zweckmäßigerweise mit einem elektrisch isolierenden transparenten Material 27 vergossen.In order to avoid an electrically conductive contact between the developer mixture 7 and the conductor tracks 22 or 26 of the board-shaped coils 6, 6 ', 6 "of the components 5 or 21, these are expediently cast with an electrically insulating, transparent material 27.

Fig. 2d zeigt eine weitere Ausführungsform des Bauteils 5 bzw. 21, das eine Induktivität aus einer Anzahl von platinenförmigen Spulen 6,6',6",... aufweist, die in der Zeichnung schematisch dargestellt sind. Die Gestalt einer einzelnen Spule entspricht einer der anhand der Fig.-2a bis 2c beschriebenen Spulenformen.2d shows a further embodiment of the component 5 or 21, which has an inductance made up of a number of plate-shaped coils 6, 6 ', 6 ", ..., which are shown schematically in the drawing. The shape corresponds to an individual coil one of the reference to Figs - coil forms described 2a to 2c..

Die Spulen sind auf beiden Seiten eines Streifens 39 und auf jeder Seite geometrisch nebeneinander angeordnet. Zur Vermeidung einer elektrisch leitenden Berührung zwischen dem Entwicklergemisch 7 und den Spulen sind diese von einer Schicht aus elektrisch isolierendem, transparenten Material 27 umgeben. Der Streifen 39 besteht beispielsweise aus einer Kunststoff-Folie, die zu beiden Seiten mit Kupfer beschichtet ist. Die einzelnen Spulen werden, wie schon voranstehend beschrieben wurde, aus der Kupferschicht auf jeder Seite des Streifens 39 herausgeätzt. Der zentrale Teil 23 einer der Spulen 6,6',6",... ist über eine Durchkontaktierungsstelle 40 mit der entsprechenden, gegenüber liegenden Spule 6,6',6",... auf der anderen Seite des Streifens 39 elektrisch verbunden. Wie schematisch in Fig. 2d angedeutet ist, sind die Spulen 6,6',6",... in einer Matrix 41 derart zusammengeschaltet, daß die Spulen in einer einzelnen Zeile 42 der Matrix 41 elektrisch in Reihe miteinander verbunden sind. Die Reihen der Matrix 41 untereinander sind dagegen elektrisch parallel geschaltet. Handelt es sich beispielsweise um eine quadratische Matrix, so ist die Gesamtinduktivität der Matrix gleich der Induktivität der einzelnen Spule 6,6',bzw. 6" usw. In der Praxis hat sich eine Matrix aus 25 Spulen, die in 5 Reihen zu je 5 Spulen angeordnet sind, bewährt. Selbstverständlich kann auch eine Matrix gewählt werden, die nicht quadratisch sondern rechteckig ist. Darüber hinaus sind die verschiedensten Kombinationen von Reihen- und Parallelschaltungen innerhalb der Matrix denkbar. Die geometrische Anordnung der Spulen auf jeder Seite des Streifens 39 erfolgt nebeneinander, unabhängig von der jeweils gewählten elektrischen Zusammenschaltung der Spulen untereinander zu einer bestimmten Matrix.The coils are arranged geometrically next to one another on both sides of a strip 39 and on each side. To avoid an electrically conductive contact between the developer mixture 7 and the coils, these are surrounded by a layer of electrically insulating, transparent material 27. The strip 39 consists for example of a plastic film which is coated on both sides with copper. As already described above, the individual coils are etched out of the copper layer on each side of the strip 39. The central one Part 23 of one of the coils 6, 6 ', 6 ", ... is electrically connected via a via point 40 to the corresponding, opposite coil 6, 6', 6", ... on the other side of the strip 39. As indicated schematically in FIG. 2d, the coils 6, 6 ', 6 ",... Are connected together in a matrix 41 in such a way that the coils in a single row 42 of the matrix 41 are electrically connected to one another in series. The rows on the other hand, the matrix 41 are electrically connected in parallel. If, for example, it is a square matrix, the total inductance of the matrix is equal to the inductance of the individual coil 6, 6 'or 6 ", etc. In practice, a matrix has developed 25 coils, arranged in 5 rows of 5 coils, have proven their worth. Of course, you can also choose a matrix that is not square but rectangular. In addition, the most varied combinations of series and parallel connections within the matrix are conceivable. The geometrical arrangement of the coils on each side of the strip 39 takes place side by side, regardless of the electrical interconnection of the coils chosen in each case to form a specific matrix.

Fig. 3 zeigt ein Blockschaltbild der Vorrichtung zur Messung der Tonerkonzentration des Entwicklergemisches 7. Das Bauteil 5 bzw. 21 ist Bestandteil eines Meßoszillators 34, der mit einem Referenzoszillator 28 verbunden ist. Die beiden Oszillatoren werden von einem Zeitgeber 30 angesteuert, der entweder den Meßoszillator 34 oder den Referenzoszillator 28 schaltet, so daß an einem Frequenz/Spannung-Wandler 29 nur jeweils die Ausgangsfrequenz eines der beiden Oszillatoren.anliegt. Die Ausgangsspannung des Wandlers 29 wird in einem Verstärker 31 entsprechend verstärkt und steuert eine Schmitt-Triggerstufe 32 an. Diese ist so eingestellt, daß ein mit ihr verbundener Motor 33 eingeschaltet wird, wenn es erforderlich ist, das Entwicklergemisch durch nachzufüllenden Toner aufzufrischen, und ausgeschaltet wird, wenn das Entwicklergemisch die gewünschte Tonerkonzentration aufweist. Der Motor 33 betätigt eine nicht gezeigte Tonerzufuhreinrichtung.3 shows a block diagram of the device for measuring the toner concentration of the developer mixture 7. The component 5 or 21 is part of a measuring oscillator 34 , which is connected to a reference oscillator 28. The two oscillators are controlled by a timer 30, which either switches the measuring oscillator 34 or the reference oscillator 28, so that only one frequency / voltage converter 29 the output frequency of one of the two oscillators. The output voltage of converter 29 is amplified accordingly in an amplifier 31 and controls a Schmitt trigger stage 32. This is set such that a motor 33 connected to it is switched on when it is necessary to replenish the developer mixture with toner to be refilled, and is switched off when the developer mixture has the desired toner concentration. The motor 33 actuates a toner supply device, not shown.

Der Schaltungsaufbau des Meßoszillators 34 ist an sich bekannt und umfaßt einen Schwingkreis, gebildet aus einem Kondensator und der Induktivität des Bauteils 5 bzw. 21. Dieser Schwingkreis ist in der Kollektorstrecke eines Transistors angeordnet, dessen Basis mit einer Spannungsquelle verbunden ist. Der Transistor ist Bestandteil einer Oszillatorschaltung, die einen weiteren Transistor aufweist. Die Emitter der beiden Transistoren sind mit dem Kollektor eines weiteren Transistors verbunden, der als Schalttransistor arbeitet und vom Zeitgeber 30 geöffnet oder geschlossen wird.The circuit structure of the measuring oscillator 34 is known per se and comprises an oscillating circuit, formed from a capacitor and the inductance of the component 5 or 21. This oscillating circuit is arranged in the collector path of a transistor, the base of which is connected to a voltage source. The transistor is part of an oscillator circuit which has a further transistor. The emitters of the two transistors are connected to the collector of a further transistor which works as a switching transistor and is opened or closed by the timer 30.

Jede Änderung der Streuinduktivität der einzelnen Spule 6 bzw. der Kombination von Spulen 6,6',6",... des Bauteils 5 bzw. 21 ändert die Frequenz des Meßoszillators 34. Die Ausgangsfrequenz des Meßoszillators 34 wird mit der festen Ausgangsfrequenz des Referenzoszillators 28 verglichen. Im allgemeinen ist die Einstellung derart, daß bei sinkender Tonerkonzentration im Entwicklergemisch die Resonanzfrequenz des Meßoszillators 34 zunimmt und damit die Abweichung dieser Frequenz von der festen Bezugsfrequenz des Referenzoszillators 28 nach oben hin zunimmt. Entsprechend dem gewählten Verstärkungsgrad des Verstärkers 31 und der Auslösespannung für die Schmitt-Triggerstufe 32 wird dann der Motor 33 in Betrieb gesetzt. Solange die Ausgangsfrequenz des Meßoszillators 34 unter dem Wert der festen Frequenz des Referenzoszillators 28 liegt, spricht die Schmitt-Triggerstufe 32 nicht an und der Motor 33 steht still, so daß kein Toner dem Entwicklergemisch zugeführt wird.Each change in the leakage inductance of the individual coil 6 or the combination of coils 6, 6 ', 6 ", ... of the component 5 or 21 changes the frequency of the measuring oscillator 34. The output frequency of the measuring oscillator 34 becomes the fixed output frequency of the reference oscillator 28. In general, the setting is such that as the toner concentration in the developer mixture decreases, the resonance frequency of the measuring oscillator 34 increases and thus the deviation of this frequency from the fixed reference frequency of the reference oscillator 28 increases upwards. The motor 33 is then started up in accordance with the selected degree of amplification of the amplifier 31 and the trigger voltage for the Schmitt trigger stage 32. As long as the output frequency of the measuring oscillator 34 is below the value of the fixed frequency of the reference oscillator 28, the Schmitt trigger stage 32 does not respond and the motor 33 stands still, so that no toner is supplied to the developer mixture.

Claims (13)

l. Vorrichtung zur Messung der Tonerkonzentration eines Entwicklergemisches aus Toner und ferromagnetischem Trägermaterial in einer elektrofotografischen Entwicklungsvorrichtung, mit einem Bauteil, das Bestandteil eines Meßoszillators ist und eine Induktivität trägt, in deren Bereich zumindest ein Teil des Entwicklergemisches gelangt, dessen Änderung der Tonerkonzentration gemessen wird, dadurch gekennzeichnet, daß das Bauteil (5) zumindest eine platinenförmige Spule (6) aufweist, deren sämtliche Leiterbahnen (22) in einer Ebene liegen.l. Device for measuring the toner concentration of a developer mixture of toner and ferromagnetic carrier material in an electrophotographic development device, with a component which is part of a measuring oscillator and carries an inductance, in the area of which at least a part of the developer mixture, whose change in the toner concentration is measured, is characterized that the component (5) has at least one plate-shaped coil (6), all of whose conductor tracks (22) lie in one plane. 2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Bauteil (5) im Inneren der Entwicklungsvorrichtung (1) angeordnet ist.2. Device according to claim 1, characterized in that the component (5) is arranged inside the developing device (1). 3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß sich das Bauteil (5) im Strom des von der fotoleitenden Oberfläche einer Trommel (2) herabrieselnden Entwicklergemisches (7) befindet.3. Apparatus according to claim 2, characterized in that the component (5) is in the stream of the developer mixture (7) trickling down from the photoconductive surface of a drum (2). 4. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Bauteil (5) auf einem Ableitblech (4) aufliegt, das tangential und geneigt zu einem Zylinder (3) zum Antragen des Entwicklergemisches (7) an die Oberfläche der Trommel (2) verläuft.4. The device according to claim 1, characterized in that the component (5) rests on a discharge plate (4) which is tangential and inclined to a cylinder (3) for applying the developer mixture (7) to the surface of the drum (2) . 5. Vorrichtung nach Anspruch l, dadurch gekennzeichnet, daß das Bauteil (21) aus einer Anzahl von platinenförmigen Spulen (6,6',6"...) besteht, die in Reihe miteinander elektrisch verbunden sind.5. The device according to claim l, characterized in that the component (21) from a number of boards shaped coils (6,6 ', 6 "...), which are electrically connected in series. 6. Vorrichtung nach den Ansprüchen 4 und 5, dadurch gekennzeichnet, daß sich die platinenförmigen Spulen (6,6',6"...) des Bauteils (21) über die Gesamtbreite des Ableitblechs (4) erstrecken.6. Device according to claims 4 and 5, characterized in that the plate-shaped coils (6, 6 ', 6 "...) of the component (21) extend over the entire width of the deflector plate (4). 7. Vorrichtung nach den Ansprüchen 1 bis 6, dadurch gekennzeichnet, daß die Leitbahnen (22) der platinenförmigen Spulen (6,6',6"...) die Form von Rechtecken aufweisen, die ausgehend von einem zentralen Teil (23) nach außen hin länger werdende Seitenkanten (24,25) besitzen.7. Device according to claims 1 to 6, characterized in that the interconnects (22) of the plate-shaped coils (6, 6 ', 6 "...) have the shape of rectangles, starting from a central part (23) have longer side edges (24, 25) on the outside. 8. Vorrichtung nach den Ansprüchen 1 bis 6, dadurch gekennzeichnet, daß die Leiterbahnen (26) der platinenförmigen Spulen (6,6',6"...) von innen nach außen spiralförmig verlaufen.8. Device according to claims 1 to 6, characterized in that the conductor tracks (26) of the plate-shaped coils (6, 6 ', 6 "...) extend spirally from the inside to the outside. 9. Vorrichtung nach einem oder mehreren der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß das Bauteil (5;21) zur Vermeidung einer elektrisch leitenden Berührung zwischen Entwicklergemisch (7') und den Leiterbahnen (22;26) der platinenförmigen Spulen (6,6',6") mit einem elektrisch isolierenden, transparenten Material (27) vergossen ist.9. The device according to one or more of claims 1 to 8, characterized in that the component (5; 21) to avoid an electrically conductive contact between the developer mixture (7 ') and the conductor tracks (22; 26) of the plate-shaped coils (6, 6 ', 6 ") is cast with an electrically insulating, transparent material (27). 10. Vorrichtung nach einem oder mehreren der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß das Bauteil (21) eine Induktivität aus einer Anzahl von platinenförmigen Spulen (6,6',6") aufweist, die auf beiden Seiten eines auf dem Bauteil (21) befestigten Streifens (39) und auf jeder Seite nebeneinander angeordnet sind.10. The device according to one or more of claims 1 to 9, characterized in that the component (21) an inductance from a number of circuit board-shaped Has coils (6, 6 ', 6 ") which are arranged on both sides of a strip (39) fastened to the component (21) and on each side next to one another. 11. Vorrichtung nach Anspruch 10, dadurch,gekennzeichnet, daß das zentrale Teil (23) einer Spule (6,6',6") auf der einen Seite des Streifens (39) über eine Durchkontaktierungsstelle (40) mit der Spule auf der anderen Seite des Streifens (39) elektrisch verbunden ist.11. The device according to claim 10, characterized in that the central part (23) of a coil (6, 6 ', 6 ") on one side of the strip (39) via a via (40) with the coil on the other Side of the strip (39) is electrically connected. 12. Vorrichtung nach einem oder mehreren der Ansprüche 1 bis 11, dadurch gekennzeichnet, daß die Spulen (6,6',6"...) in einer Matrix (41) derart zusammengeschaltet sind, daß die Spulen in jeder Zeile (42) der Matrix (41) elektrisch in Reihe und die Reihen der Matrix (41) untereinander elektrisch parallel geschaltet sind.12. The device according to one or more of claims 1 to 11, characterized in that the coils (6, 6 ', 6 "...) are interconnected in a matrix (41) such that the coils in each row (42) the matrix (41) are electrically connected in series and the rows of the matrix (41) are electrically connected in parallel with one another. 13. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, daß die Gesamtinduktivität der Matrix (41) gleich der Induktivität einer einzelnen Spule (6,6',6",...) ist.13. The apparatus according to claim 12, characterized in that the total inductance of the matrix (41) is equal to the inductance of a single coil (6,6 ', 6 ", ...).
EP78100137A 1977-06-18 1978-06-12 Device for measuring the toner concentration in a development mixture Expired EP0000136B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2727402A DE2727402C2 (en) 1977-06-18 1977-06-18 Device for measuring the toner concentration of a developer mixture
DE2727402 1977-06-18

Publications (2)

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EP0000136A1 true EP0000136A1 (en) 1979-01-10
EP0000136B1 EP0000136B1 (en) 1982-09-22

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EP78100137A Expired EP0000136B1 (en) 1977-06-18 1978-06-12 Device for measuring the toner concentration in a development mixture

Country Status (5)

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US (1) US4257348A (en)
EP (1) EP0000136B1 (en)
JP (1) JPS547938A (en)
CA (1) CA1111491A (en)
DE (2) DE2727402C2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0029710A1 (en) * 1979-11-24 1981-06-03 Hitachi, Ltd. Toner concentration detecting apparatus
FR2481821A1 (en) * 1980-05-02 1981-11-06 Gestetner Mfg Ltd DEVELOPING DEVICE FOR ELECTROPHOTOGRAPHIC COPIER WITH DRY PIGMENT REVELATOR
US20190112679A1 (en) * 2016-04-01 2019-04-18 Pramet Tools, S.R.O. Surface hardening of cemented carbide body

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS602599Y2 (en) * 1978-11-15 1985-01-24 コニカ株式会社 Toner concentration detection device
JPS55121459A (en) * 1979-03-14 1980-09-18 Hitachi Ltd Developer supervising device
JPS5675662A (en) * 1979-11-26 1981-06-22 Hitachi Ltd Operating method of electrophotographic apparatus
JPS56102874A (en) * 1980-01-19 1981-08-17 Canon Inc Developer replenishing device
JPS56121068A (en) * 1980-02-27 1981-09-22 Mita Ind Co Ltd Developing device of electrostatic copying machine
JPS5726879A (en) * 1980-07-23 1982-02-13 Mita Ind Co Ltd Control device for replenishing of developer
US4357901A (en) * 1981-09-03 1982-11-09 Bunnington Corporation Method and system for magnetically sensing and controlling toner concentration and optical density of copies in electrostatic reproduction
JPS5910814A (en) * 1982-07-12 1984-01-20 Hitachi Metals Ltd Level sensor for toner
US4706032A (en) * 1986-03-17 1987-11-10 Eastman Kodak Company Toner concentration monitor
US5196803A (en) * 1991-08-01 1993-03-23 Xerox Corporation Apparatus and method for determining the voltage breakdown and conductivity of particulate material

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3504276A (en) * 1967-04-19 1970-03-31 American Mach & Foundry Printed circuit coils for use in magnetic flux leakage flow detection
DE2525952A1 (en) * 1974-07-17 1976-02-05 Savin Business Machines Corp MONITORING SYSTEM FOR TONER CONCENTRATION, IN PARTICULAR FOR DRY COPY MACHINES
DE2746352A1 (en) * 1976-10-16 1978-04-20 Hitachi Ltd TONER CONCENTRATION SENSOR

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547407A (en) * 1948-06-18 1951-04-03 Peyton J Nelson Apparatus for detecting metal objects on a moving belt
US3572551A (en) * 1969-03-27 1971-03-30 Rca Corp Apparatus for monitoring and controlling the concentration of toner in a developer mix
US3588687A (en) * 1969-11-18 1971-06-28 Us Army Sensing coil arrangement for a metal detector
US3892672A (en) * 1970-08-21 1975-07-01 Addressograph Multigraph Automatic toner concentrate detector and control device
JPS52123242A (en) * 1976-04-09 1977-10-17 Hitachi Ltd Detector for toner mixing ratio of developing agent

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3504276A (en) * 1967-04-19 1970-03-31 American Mach & Foundry Printed circuit coils for use in magnetic flux leakage flow detection
DE2525952A1 (en) * 1974-07-17 1976-02-05 Savin Business Machines Corp MONITORING SYSTEM FOR TONER CONCENTRATION, IN PARTICULAR FOR DRY COPY MACHINES
DE2746352A1 (en) * 1976-10-16 1978-04-20 Hitachi Ltd TONER CONCENTRATION SENSOR

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0029710A1 (en) * 1979-11-24 1981-06-03 Hitachi, Ltd. Toner concentration detecting apparatus
FR2481821A1 (en) * 1980-05-02 1981-11-06 Gestetner Mfg Ltd DEVELOPING DEVICE FOR ELECTROPHOTOGRAPHIC COPIER WITH DRY PIGMENT REVELATOR
US20190112679A1 (en) * 2016-04-01 2019-04-18 Pramet Tools, S.R.O. Surface hardening of cemented carbide body

Also Published As

Publication number Publication date
JPS623950B2 (en) 1987-01-28
DE2727402B1 (en) 1978-08-17
DE2862038D1 (en) 1982-11-04
JPS547938A (en) 1979-01-20
US4257348A (en) 1981-03-24
CA1111491A (en) 1981-10-27
EP0000136B1 (en) 1982-09-22
DE2727402C2 (en) 1979-04-19

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