US3924462A - Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine - Google Patents

Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine Download PDF

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Publication number
US3924462A
US3924462A US278254A US27825472A US3924462A US 3924462 A US3924462 A US 3924462A US 278254 A US278254 A US 278254A US 27825472 A US27825472 A US 27825472A US 3924462 A US3924462 A US 3924462A
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United States
Prior art keywords
charge pattern
photoconductor
electrodes
test charge
measuring
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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 - Lifetime
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US278254A
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English (en)
Inventor
Hartmut Bock
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Hoechst AG
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Hoechst AG
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Publication date
Priority claimed from DE19712139323 external-priority patent/DE2139323C3/de
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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
    • G03G15/0855—Detection or control means for the developer concentration the concentration being measured by optical means
    • 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
    • G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
    • G03G15/0891—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity for conveying or circulating developer, e.g. augers
    • 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
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • G03G15/5033—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor
    • G03G15/5041—Detecting a toner image, e.g. density, toner coverage, using a test patch

Definitions

  • 118/637 X tographic cycle, sliding contact rings and/or wiper 3,399,652 9/1968 Gawron 117/ 17.5 X contacts for applying potential to the electrodes from ,901 11/1968 Dost et a1.
  • 118/637 X a voltage source and comparative light beams from g e the same source for carrying out the measurement of 00 FIG e 3,527,387 9/1970 Wilson 1.
  • 118/637 X a developed test charge pattern one of the Enamels affected by the developed test charge pattern while 3,604,939 9/1971 Maksymlak et al..
  • This invention concerns a method of and apparatus for measuring or measuring and controlling the toner concentration in electrophotographic reproduction machines.
  • the toner may be a colored synthetic resin powder and the carrier a granular material consisting of glass, or iron coated with synthetic resin.
  • the carrier is used for carrying the toner and in charging it triboelectrically.
  • the toner is finely distributed in a liquid having a high specific resistance.
  • the toner is used for inking up the copies.
  • the toner is used up at a varying rate during developing, depending upon the nature and number of the copies. Further amounts of toner must be added in order to keep the inking up effect as constant as possible.
  • toner concentration Various optical methods of measuring toner concentration are known.
  • One of these methods consists in measuring the reflection from the developed, i.e., toner-covered photoconductor.
  • this measurement can be carried out with the aid of a test image which is located at the edge of the photoconductor and on to which light is directed.
  • the reflection is measured from a toner-covered electrode, not participating in the actual electrophotographic cycle.
  • the first-mentioned known methods have the disadvantage that the measurements are dependent upon the properties of the photoconductor and upon the charge and the type of exposure. Restandardization may become necessary when the photoconductor, the corona voltage and/or the lamps are changed.
  • the methods of the second group have the disadvantage that the application of the toner does not occur under the same conditions as in the actual development of the photoconductor. There thus exists the danger of the measurement indicating a proportion of toner that is different from that present in the developer.
  • the object of the present invention is therefore to provide a method of and apparatus for measuring or measuring and controlling the toner concentration, in which the measurements can be carried out in the reproduction machine in a manner which is to a far reaching extent independent of the parameters of the photoconductor, of the exposure and, if necessary, of the characteristics of the charging means.
  • the invention accordingly provides in the first place a method of measuring or measuring and controlling the toner concentration of a developer circulating in an electrophotographic reproduction machine, in which method a. a test charge pattern based on the said toner concentration is formed, which pattern is one that is 2 independent of the photoconductor of the machine,
  • the invention further provides an apparatus for use in the method of the invention, said apparatus including at least one electrode for producing the said test charge pattern, said electrode or electrodes being so formed and arranged in an electrophotographic reproduction machine containing a photoconductor, that together with the photoconductor it or they can be moved past the various operative devices in an electrophotographic cycle, and further including means for applying potential to the electrode or electrodes and means for determining an optical property of a test charge pattern after development thereof.
  • the method of the invention offers the particular advantage that the toner concentration is measured, on
  • the one hand by reference to a toner treatment that is identical to that used for developing the image, and on the other hand independently of the other parameters of the electrophotographic reproduction cycle.
  • the method of the invention is not complicated, and the apparatus of the invention can be'incorporated without any great difficulty in electrophotographic equipment of the kind now manufactured on a mass-production scale.
  • the apparatus and the method of the invention are suitable for developing the charge image on the photoconductor by means of a liquid.
  • That form of the method of the invention in which charged metal electrodes themselves are used as the test charge pattern and are developed together with the photoconductor exposed in the manner to produce an image carries the advantage that it is also completely independent of the corona charge.
  • Etching and vaporization processes for producing the electrodes on insulating carrier material have reached a relatively advanced stage of development, and it is possible to produce appropriate electrodes ,which are able to withstand the mechanical stresses occurring in the electrophotographic method for at least as long as the photoconductor.
  • the method of the invention can also be used when the electrodes are coated with a layer of insulating material.
  • the layer of insulating material is charged, and the voltage conditions on the underlying electrodes are so varied in a prescribed manner that a test charge pattern corresponding to the electrodes is formed on the layer of insulating material.
  • FIG. 1 is a diagrammatic section of an electrophotophotographic reproduction machine with the measuring and controlling apparatus of the invention
  • FIG. 2 is a perspective view of a measuring strip
  • FIG. 3 is a part perspective, part diagrammatic illustration of the measuring apparatus
  • FIG. 4 is a perspective view on a larger scale, partly in section, of part of the measuring apparatus
  • FIG. 5 is a diagrammatic section of part of the measuring apparatus with a measuring strip disposed alongside a photoconductor, and
  • FIG. 6 is a similar view of a different embodiment.
  • a photoconductor 2 which may be insulated from drum 1 by carrier 38 is electrically'charged by a charging device 3, is exposed to the light from an exposure means 4 and is developed with the aid of developer 8 in a developing zone 33 in a developing device 5 consisting of a toner supply container 6 and a conveyor system 7.
  • the developer device 5 may instead be of the kind designed to develop the charge image with the aid of a liquid.
  • the toner image is transferred from the photoconductor 2 to paper 9 at a transfer device 10, and is fixed on the paper 9 at a fixing device 13.
  • the photoconductor 2 is then discharged at a discharging unit 11 and is cleansed from toner by a cleaning device 12.
  • a measuring strip 14 is located on the drum 1.
  • This strip 4 is shown in the developed state in FIG. 2. It consists of a carrier strip 16, made for example of the material HOSTAPl-IAN, on which two spaced, meshing electrodes 17 are provided. These electrodes can be formed, for example, by etching a metal coating applied to the insulating material, or by a metal-vaporization deposition technique.
  • a charge pattern is produced with the aid of the measuring strip 14 in a manner to be hereinafter described, which pattern and the photoconductor are together subjected to precisely the same treatment in the electrophotographic reproduction machine.
  • the degree of darkening by inking up of the developed charge pattern is measured in a measuring device 15.
  • a controlling device 37 may be provided which, by means of a feed roller 36, supplies toner to the developer 8 whenever the darkening of the measuring strip 14 falls below a certain level.
  • the measuring-strip 14 with the electrodes 17 can be used in different ways for producing the test charge pattern.
  • the electrodes 17 are nearer to the drum 1 than the carrier strip 16 and are insulated from the developing zone 33 of the drum.
  • a plurality of pairs of electrodes 17a, 17b, etc. are distributed over the periphery of the drum 1.
  • the voltage from a voltage source 35 is applied to that pair of electrodes 17b that is for the time being located below the charging device 3 (e.g., a corona discharge device).
  • the pair of electrodes 17a that has just moved into the developing zone 33 is electrically connected as indicated by the grounding of one of two wiper contacts 18. In this way a test charge pattern corresponding to the electrode pattern is produced in the developing zone 33 on that side of the strip 14 facing the developing device 5.
  • the creation of the test charge pattern is based on the following effect: a charge of the same potential is applied to the upper face of the carrier strip 16 with the aid of the charging device 3, whereas a differing potential is applied to the insulated underlying electrodes, so that a potential difference occurs between the electrodes.
  • Each electrode and the associated charged zone of the carrier strip 16 form a capacitor.
  • the electrical fields or the electrical energies in the two geometrically identical capacitors are different because of the potential difference.
  • the potential difference at the individual capacitor or the electrical energy stored therein, remains constant.
  • a charge pattern (a voltage pattern) has been created.
  • each common electrode potential is so selected that the level of the potential of the applied charges does not rise, but either falls in one of the zones opposite the electrodes and remains constant in the other, or falls in both zones.
  • the test charge pattern is no longer influenced by the properties of the photoconductor, it is still dependent upon the characteristics of the charging device 3. This dependence is avoided by a second procedure.
  • the two electrodes 17 face outwards (FIGS. 3, 5 and 6).
  • Voltage iscontinuously applied to the electrodes 17.
  • the electrodes connected to the voltage source 35 con sti tute the charge pattern which is developed in thedeveloping zone 33.
  • Charging with a corona discharge device is no longer necessary, and the charge pattern'is independent of the charging device 3.
  • a corona charge is not inconvenient since it has no effect upon the test charge pattern and the degree of darken-- phragm 24 and a photosensitive element 25 (e.g., a
  • the reflected light is 'measured at a suitable angle dependent upon the type of toner and the type of test strip.
  • Two'windows 26 and 27 and a housing 28 protect the measuring apparatus against dust.
  • a second light beam II emanates from the same light source 20 and passes through the same windows 26 and 27 as the first light beam.
  • Two lenses 29 and 30, a diaphragm 31 and a further photosensitive 1 element 32 are used for carrying out the measurements.
  • the cross-sections of the light beams I and II are the angle of the windows 26 and 27 with respect to the light beams are so selected that both beams penetrate the same window surfaces. Thus any contamination of the windows weakens the light beams to the same extent.
  • Comparison e.g., in a bridge circuit
  • Comparison of the amounts of light striking the two photosensitive elements (25 and 32) thus eliminates the effects of contamination of the windows by dust and of fluctuation in the intensity of the light source.
  • the electrodes 17 When uncovered, the electrodes 17 can be connected directly to voltage sources 35 through wiper contacts 18 as illustrated in FIGS. 3, 5 and 6, in a' simplified manner. In cases where the electrodes are not uncovered, as for example in the arrangement illustrated in FIG. 4, and also for the purpose of avoiding any likelihood of breakdown, it is expedient to provide separate sliding contact rings or segments 22 of such rings, and to connect these electrically to the electrodes. These sliding contact rings can also be fitted at the ends of the drum.
  • a method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine comprising applying different voltages to spaced meshing electrodes on a drum carrying the photoconductor whereby the electrodes are arranged besides the exposure zone of the photoconductor, charging an insulating layer formed on the electrodes simultaneously with the photoconductor, connecting the electrodes just moved into the developing zone by grounding each after the charging step, applying a common electrical potential to the electrodes, a test charge pattern being thereby formed on the insulating layer, developing the test charge pattern based on a treatment identical to that used for developing the latent charge image, said test charge pattern being independent of the photoconductors properties and treatment and of the other parameters of the electrophotographic reproduction cycle, and measuring the darkness of the test charge pattern which is a measure of the toner density by optical reflection carried out by light beams from the same light source, one of the beams being affected by the developed test charge pattern and the other being an unaffected reference beam.
  • a method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine comprising forming a. a test charge pattern with the aid of spaced meshing electrodes placed under a voltage on a measuring strip which is located on a drum carrying the photoconductor, whereby the measuring strip is arranged besides the exposure zone of the photoconductor,
  • test charge pattern based on a treatment identical to that used for developing the latent charge image, said test charge pattern being independent of the photoconductors properties and treatment and of the other parameters of the electrophotographic reproduction cycle, and

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Or Security For Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
US278254A 1971-08-06 1972-08-07 Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine Expired - Lifetime US3924462A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712139323 DE2139323C3 (de) 1971-08-06 Vorrichtung zur Messung der Tonerkonzentration des Entwicklers in einer Entwicklungsstation

Publications (1)

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US3924462A true US3924462A (en) 1975-12-09

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US (1) US3924462A (de)
JP (1) JPS5538666B2 (de)
AU (1) AU477133B2 (de)
FR (1) FR2155223A5 (de)
GB (1) GB1401659A (de)
NL (1) NL7210357A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000944A (en) * 1975-02-18 1977-01-04 Xerox Corporation Photoreceptor for electrostatic reproduction machines with built-in electrode
US4082445A (en) * 1975-11-21 1978-04-04 Xerox Corporation Toner control system for an electrostatic reproduction machine
US4211558A (en) * 1975-07-23 1980-07-08 Konishiroku Photo Industry Co., Ltd. Color printing method
US4347299A (en) * 1978-08-16 1982-08-31 Minolta Camera Kabushiki Kaisha Method of controlling toner concentration for electrophotographic copying apparatus
US4607944A (en) * 1985-06-07 1986-08-26 Eastman Kodak Company Apparatus for controlling toner replenishment in electrographic copier

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52119233A (en) * 1976-03-08 1977-10-06 Sharp Corp Toner supply means
US4183657A (en) * 1978-04-10 1980-01-15 International Business Machines Corporation Dynamic reference for an image quality control system
CA1128114A (en) * 1978-04-10 1982-07-20 Clement C. Wilson Test cycle quality control system for an electrophotographic machine
JPS5433727A (en) * 1978-08-10 1979-03-12 Canon Inc Zerography
JPS5433728A (en) * 1978-08-10 1979-03-12 Canon Inc Zerography

Citations (25)

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US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3129113A (en) * 1962-02-13 1964-04-14 Xerox Corp Automatic powder applicator apparatus
US3233781A (en) * 1963-05-08 1966-02-08 Savin Business Machines Corp Toner control system
US3348521A (en) * 1962-08-28 1967-10-24 Xerox Corp Automatic toner control system
US3348522A (en) * 1962-08-28 1967-10-24 Xerox Corp Automatic toner control system
US3348523A (en) * 1965-04-07 1967-10-24 Xerox Corp Automatic toner control system
US3376854A (en) * 1966-06-01 1968-04-09 Xerox Corp Automatic toner dispensing control
US3376853A (en) * 1966-04-29 1968-04-09 Xerox Corp Electrostatic toner control
US3382796A (en) * 1967-01-10 1968-05-14 Continental Can Co Apparatus for continuous electrostatic screen printing with density control
US3399652A (en) * 1967-06-14 1968-09-03 Addressograph Multigraph Automatic toner concentrate detector
US3409901A (en) * 1967-07-12 1968-11-05 Ibm Automatic toner concentration control for use with crt input
US3430606A (en) * 1968-01-02 1969-03-04 Xerox Corp Electroscopic particle sensor
US3526338A (en) * 1968-01-02 1970-09-01 Xerox Corp Method and controller for dispensing electroscopic material
US3527387A (en) * 1968-05-24 1970-09-08 Xerox Corp Developer replenishing programming system
US3659556A (en) * 1970-08-19 1972-05-02 Xerox Corp Programmable toner dispenser
US3674353A (en) * 1971-07-01 1972-07-04 Eastman Kodak Co Toner concentration control apparatus
US3677222A (en) * 1969-02-24 1972-07-18 Canon Kk Device for automatically regulating the concentration of developing solution
US3682132A (en) * 1969-03-03 1972-08-08 Xerox Corp Automatic developer controller
US3712203A (en) * 1969-11-15 1973-01-23 Iwatsu Electric Co Ltd Automatic control device for the toner concentration within a developer in an electrostatic copy machine
US3727065A (en) * 1969-10-17 1973-04-10 Xerox Corp Automatic developability control system
US3756192A (en) * 1971-12-17 1973-09-04 Ibm Automatic toner concentration control system
US3777173A (en) * 1972-02-22 1973-12-04 Dyke Res Van Xerographic toner concentration measuring apparatus and method
US3780299A (en) * 1971-08-06 1973-12-18 Kalle Ag Device for the production of a measuring signal or control
US3791744A (en) * 1972-02-22 1974-02-12 Dyk Res Corp Van Xerographic toner concentration measuring apparatus and method

Patent Citations (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3129113A (en) * 1962-02-13 1964-04-14 Xerox Corp Automatic powder applicator apparatus
US3348521A (en) * 1962-08-28 1967-10-24 Xerox Corp Automatic toner control system
US3348522A (en) * 1962-08-28 1967-10-24 Xerox Corp Automatic toner control system
US3233781A (en) * 1963-05-08 1966-02-08 Savin Business Machines Corp Toner control system
US3348523A (en) * 1965-04-07 1967-10-24 Xerox Corp Automatic toner control system
US3376853A (en) * 1966-04-29 1968-04-09 Xerox Corp Electrostatic toner control
US3376854A (en) * 1966-06-01 1968-04-09 Xerox Corp Automatic toner dispensing control
US3382796A (en) * 1967-01-10 1968-05-14 Continental Can Co Apparatus for continuous electrostatic screen printing with density control
US3399652A (en) * 1967-06-14 1968-09-03 Addressograph Multigraph Automatic toner concentrate detector
US3409901A (en) * 1967-07-12 1968-11-05 Ibm Automatic toner concentration control for use with crt input
US3430606A (en) * 1968-01-02 1969-03-04 Xerox Corp Electroscopic particle sensor
US3526338A (en) * 1968-01-02 1970-09-01 Xerox Corp Method and controller for dispensing electroscopic material
US3527387A (en) * 1968-05-24 1970-09-08 Xerox Corp Developer replenishing programming system
US3604939A (en) * 1968-05-24 1971-09-14 Xerox Corp Toner concentration sensing apparatus having plural sensors and a flow control means for each sensor
US3677222A (en) * 1969-02-24 1972-07-18 Canon Kk Device for automatically regulating the concentration of developing solution
US3682132A (en) * 1969-03-03 1972-08-08 Xerox Corp Automatic developer controller
US3727065A (en) * 1969-10-17 1973-04-10 Xerox Corp Automatic developability control system
US3712203A (en) * 1969-11-15 1973-01-23 Iwatsu Electric Co Ltd Automatic control device for the toner concentration within a developer in an electrostatic copy machine
US3659556A (en) * 1970-08-19 1972-05-02 Xerox Corp Programmable toner dispenser
US3674353A (en) * 1971-07-01 1972-07-04 Eastman Kodak Co Toner concentration control apparatus
US3780299A (en) * 1971-08-06 1973-12-18 Kalle Ag Device for the production of a measuring signal or control
US3756192A (en) * 1971-12-17 1973-09-04 Ibm Automatic toner concentration control system
US3777173A (en) * 1972-02-22 1973-12-04 Dyke Res Van Xerographic toner concentration measuring apparatus and method
US3791744A (en) * 1972-02-22 1974-02-12 Dyk Res Corp Van Xerographic toner concentration measuring apparatus and method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000944A (en) * 1975-02-18 1977-01-04 Xerox Corporation Photoreceptor for electrostatic reproduction machines with built-in electrode
US4211558A (en) * 1975-07-23 1980-07-08 Konishiroku Photo Industry Co., Ltd. Color printing method
US4082445A (en) * 1975-11-21 1978-04-04 Xerox Corporation Toner control system for an electrostatic reproduction machine
US4347299A (en) * 1978-08-16 1982-08-31 Minolta Camera Kabushiki Kaisha Method of controlling toner concentration for electrophotographic copying apparatus
US4607944A (en) * 1985-06-07 1986-08-26 Eastman Kodak Company Apparatus for controlling toner replenishment in electrographic copier

Also Published As

Publication number Publication date
JPS4829448A (de) 1973-04-19
DE2139323A1 (de) 1973-02-15
AU477133B2 (en) 1976-10-14
GB1401659A (en) 1975-07-16
JPS5538666B2 (de) 1980-10-06
DE2139323B2 (de) 1977-06-23
AU4531372A (en) 1974-02-07
NL7210357A (de) 1973-02-08
FR2155223A5 (de) 1973-05-18

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