US3756192A - Automatic toner concentration control system - Google Patents

Automatic toner concentration control system Download PDF

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Publication number
US3756192A
US3756192A US00209042A US3756192DA US3756192A US 3756192 A US3756192 A US 3756192A US 00209042 A US00209042 A US 00209042A US 3756192D A US3756192D A US 3756192DA US 3756192 A US3756192 A US 3756192A
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United States
Prior art keywords
light
developer material
toner
signal
concentration
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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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US00209042A
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English (en)
Inventor
H Locklar
D Tao
L Tarver
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International Business Machines Corp
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International Business Machines Corp
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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
    • 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

  • a surface bearing a latent electrostatic image is developed by applying a developer material comprising toner and a carrier material to the surface. A portion of the applied toner is selectively attracted to the image areas of the surface and the remainder of the developer material is removed and allowed to recirculate to form subsequent images. In order to assure that there is a sufficient and proper amount of toner in the developer material, it is necessary to add quantities of toner material to the developer material to replace that which has been used for imaging.
  • the present invention incorporates a calibrated reference which is periodically interposed between the sensing apparatus and the developer material to be sensed thereby effecting the generation of an electrical signal having an AC component whenever there is a difference in the intensity of light reflected from the reference and that reflected from the developer material.
  • a phase sensing circuit is provided to detect the position of the peak of the AC signal component with reference to the position of the calibrated reflector thereby avoiding effects of component drift inherent in amplitude detection systems. Utilization of a single sensing device assures uniformity of system operation.
  • a plurality of selectable reference devices are incorporated into the system thereby providing a wide latitude of selectable, controllable toner concentrations and/or developer material components.
  • An additional control of the light source spectral emission provides additional concentration settings.
  • FIG. 4 is a circuit diagram of the phase indicator logic of the toner concentration control system.
  • FIG. 5 is a circuit diagram of the flow indicator logic of the toner concentration control system.
  • the rotating plate thereafter passes a developer station 19 where multicomponent developer material including electrostatically charged toner is applied to the surface of the electrostatic photosensitive plate 11 containing the latent electrostatic image thereon.
  • the toner particles are preferentially attracted to the latent image on the plate 11 and are subsequently transferred to a support surface 21 by conventional electrostatic transfer or by heat transfer.
  • the plate continues to rotate past a cleaning station 25 which removes residual toner from the surface thereof.
  • the thus delivered developer material cascades downwardly over the rotating plate 11 and the triboelectrically charged toner particles adhere to the electrostatic latent image on the plate 11.
  • the carrier material and toner material not adhering to the plate fall back into the sump portion 31 for subsequent mixing with toner particles 37.
  • the toned latent image is transferred to a support surface 21 as the plate 11 continues its rotational motion.
  • the proper ratio of toner to carrier in the developer material be maintained. By varying this ratio, for example, by having excessive toner, dark blurred overdeveloped images are obtained. When too little toner is present in the developer material, light underdeveloped images are obtained.
  • a sample of the developer material is obtained and optically sensed to determine its light reflectance characteristic. Since the reflectance characteristic of the toner particles differs from that of the carrier particles, a properly proportioned mixture of the developer material will have a predetermined light reflectance characteristic. This characteristic would, of course, differ for each different toner or carrier which may be selected for a system. Since the toner particles are generally darker than the carrier particles, the amount of light reflected becomes greater as the proportion of toner to carrier in the mixture becomes less and, conversely, less light is reflected from the mixture as the ratio of toner to carrier increases.
  • a diverter 51 is positioned in the flow path of the developer material as it tumbles from the bucket conveyor 41 toward the plate 11 and continually captures a portion of the developer material as it is delivered from the bucket conveyor.
  • the developer material is delivered from the diverter 51 to a chute member 53 containing a viewing window 55 therein.
  • the developer material flows through the chute member 53 and exits therefrom into the sump portion 31 of the developer station 19.
  • An actuable shutter member 57 halts developer flow through the exit of the chute member 53 thereby causing the developer material to halt within the chute member and thus remain stationary at the viewing window 55.
  • the signal from the reed switch 75 actuates a single shot 77 which in turn provides a logic signal input to the delay unit 78.
  • the logic signal is delayed by a selectable amount in accordance with the desired image density and, hence, the tooth 65 selected as a reference.
  • the delayed signal is provided as an input to the replenisher motor control logic 79.
  • the photosensing device 61 is presented with light which is alternately reflected from the teeth 65 and from the developer materiallocated in the viewing window 55.
  • the electrical signal obtained from the photosensing device will contain an AC component when the intensity of the light reflected from the developer material differs from that of the light reflected from the teeth 65. If the teeth all have the same reflectance value, no AC signal would be present when the reflectance from the developer material is the same as that from the teeth.
  • the AC component will have either a maximum value or a minimum .value when the photosensing device 61 is viewing a tooth 65 depending upon whether the developer material in the viewing window 55 is darker or lighter than the tooth.
  • the toner dispenser can be turned on in a manner to be described and caused to remain on until the developer material becomes darker than the tooth.
  • a simple phase detection circuit can be utilized to provide an indication of the position of the tooth with respect to the peak of the AC signal.
  • the magnetic actuator 73 and reed switch provide the necessary synchronizing signal to determine whether the photodetector is viewing a tooth 65 or the developer material in the viewing window 55.
  • the replenisher motor control logic 79 When the developer material appearing in the viewing window 55 is lighter than the tooth 65 utilized as a reference, the replenisher motor control logic 79 generates a signal which actuates the replenisher motor 81.
  • the replenisher motor 81 drives a toner replenishing drum 83.
  • the toner replenishing drum 83 has slots located in the surface thereof which carry toner particles from the resevoir 85 to a position where they fall into the sump portion 31.
  • Such a toner dispensing apparatus is described in U. S. Pat. No. 3,572,555 issued Mar. 30, 1971, assigned to the assignee of this invention.
  • the shutter member 57 is actuated by a cam 87 to prevent developer flow through the chute member 53.
  • the sample switch 89 is closed providing an input signal to the replenisher motor con trol logic 79. This input signal prevents the threshold detection logic 63 from actuating the replenisher motor 81 during those time periods when developer material is flowing through the chute member 53.
  • switch 89 is closed thereby providing an electrical signal which enables the output signal of the photosensing device 61 to be utilized to control the toner replenisher motor 81 of FIG. 1. That is, although the chopper wheel 67 and the magnetic actuator 73 are in operation at all times,.when the reproduction machine is in operation, the signal from the photosensing device 61 is sampled only when the shutter member 57 has stopped the fiow of developer material through the opening 95.
  • FIG. 3 of the drawings a circuit diagram of the threshold detection logic of the toner concentration control system is depicted.
  • This logic is responsive to the photosensing device 61 which, by way of example, could comprise an RCA 93 1A photo multiplier tube and comprises threshold circuits 101 and 103 and a differential amplifier.
  • the AC component of the signal from the photosensing device 61 is supplied to the differential amplifier transistor 105 which, along with transistor 107, differentially amplifies the signal and applies the thus amplified signal to the threshold circuits 101 and 103 so that the positively amplified signal will drive one threshold circuit while the negatively amplified signal drives the other circuit.
  • the threshold circuits yield output signals V1 and V2 which are pulses occurring at the positive and negative peaks, respectively, of the differentially amplified signal when the magnitude of this AC signal is above the threshold values.
  • the combination of resistors 109 and 111 and resistors 113 and 115 determine the peak magnitudes necessary to yield the output pulses V1 and V2.
  • threshold circuits 101 and 103 thus prevent a noise signal supplied by the photosensing device 61 from effecting output pulses which would drive the replenisher motor control logic and further provide for adjustment in the setting of the desired toner concentration. Since two threshold levels are involved, by properly adjusting the resistor combination, levels can be set which will give a voltage signal V1 when the mixture is too lean in toner and will give a voltage signal V2 when the mixture is too rich in toner. This double set point arrangement allows for a latch type circuit to provide the necessary signal to the replenisher motor.
  • the out-of-phase or negatively amplified signal output of the differential amplifier of FIG. 3 depicted by wave form 143 has a negative peak 145 which occurs at the same time as the pulse V3 of wave form 141.
  • an output pulse V1 as indicated by wave form 149 is supplied by the threshold detection circuit of FIG. 3.
  • the next negative peak 151 of the wave form 143 corresponds to the light reflected from a nonselected tooth 65 of FIG. 1 which may or may not be below the threshold as indicated by line 147.
  • the wave form is above the threshold.
  • FIG. 7 of the drawings a wave form diagram of the various signals of the circuits of the toner concentration control system is depicted. These wave forms occur when a rich mixture is detected.
  • the negative peak of the out-of-phase or negatively amplified photosensing device signal as indicated by wave form 163, occurs out of phase with the single shot pulse depicted by wave form 165.
  • the negative peaks of the wave form 167 corresponding to the in-phase amplified sig-- nal overlap the output pulse of the single shot.
  • pulses V1 denoted by wave form 169 are out of phase with the single shot
  • the pulses V2, denoted by wave form 171 are in phase with the single shot.
  • FIG. 8 of the drawings a logic block diagram of the replenisher motor control logic of the toner concentration control system is depicted.
  • the flow indicator logic provides an output signal V4 indicating that sampling is to be effected
  • the logic inverter units and 177 provide an output signal, ADD.
  • the ADD signal drives the magnet driver 179 which, in turn, actuates the replenisher motor 81.
  • the replenisher motor effects the dispensing of additional quantities of toner into the developer mix. This motor continues to operate until the ADD signal is dropped.
  • the out-of-phase output V2 of the differential amplifier does not overlap with the signal .V3 until a rich mixture is detected. Accordingly, the inverter 181 provides an output signal V5 until a rich mixture is detected. This singal, V5, along with the ADD signal provide an input to the inverter 175 which keeps the ADD signal on until the V5 signal is dropped when a rich mixture is detected.
  • This double set point control thus enables the threshold at which the replenisher motor 81 is actuated to be controlled as well as controlling the threshold level at which the replenisher motor 81 is turned off.
  • a further selectable means of controlling the toner concentration within a selectable desired range is to provide differing gray scales on each of the teeth 65 of the chopper wheel 67.
  • a delay control 78 delays the output signal of the single shot 77 by the amount of time that it takes for the desired tooth to rotate to the viewing position. Thus, if it were desirous to compare the intensity of light reflected from the developer material with the gray scale on tooth 65a, a delay would be selected corresponding to the amount of time that it takes for the chopper wheel to rotate one half of a revolution.
  • a simple operator control 183 can be utilized to select the desired delay network.
  • Light from the light source 59 is alternately reflected from the teeth of the rotating chopper wheel 67 and from the developer material located within the viewing window 55 and is presented to the photosensing device 61.
  • the teeth 65 each have a calibrated gray scale thereon corresponding to a desired toner concentration.
  • the photosensing device 61 provides an AC signal output to the threshold detection logic 63. Additionally, a phase pulse is generated by the coaction of the magnetic actuator 73 and the reed switch 75 which electronically indicates that a tooth 65 is being viewed at the time of occurrence of the phase pulse.
  • each of the teeth 65 differing gray scales are provided on each of the teeth 65.
  • Operator selection of a desired density selects the tooth 65 which will be utilized in controlling the developer material concentration.
  • the operator selection effects an appropriate delay of the signal generated by the reed switch 75 so that the tooth corresponding to the desired setting is adjacent the viewing station at the time the gating signal is provided by the delay unit 78 to the replenisher motor control logic 79.
  • additional settings may be selected for a given tooth setting.
  • various circuits can be utilized to detect the output of the photosensing device and convert the AC signal output thereof into a logical signal indicative of the toner concentration within the developer material.
  • various well-known dispensing devices can be utilized including those which dispense a measured quantity of toner material for each actuation thereof.
  • various forms of developing stations such as a magnetic brush developing station can be utilized.
  • Apparatus for controlling the concentration of multicomponent developer material including toner for use in an electrostatic reproduction apparatus including:
  • a developer unit fixedly mounted and having a viewing window for presenting developer material illuminated by said light source;
  • photosensing means alternately responsive to light reflected from said illuminated developer material presented by said viewing window and to light reflected from said light reflector when said light reflector is in said second position for converting light into an electrical signal having an AC component when the intensity of light from the light reflector differs from the intensity of light from the developer material, said light reflector being interposed between said viewing window and said photosensing means when in said second position for preventing light from said developer material from striking said photosensing means;
  • control means responsive to said electrical signal for actuating said actuatable means for dispensing toner.
  • the toner concentration control system set forth in claim 1 further comprising means for effecting motion of said developer material past the viewing window;
  • actuatable halting means for halting the motion of said developer material at the viewing window
  • control means being further responsive to the halting signal for actuating said actuatable means.
  • selection means for selecting one of said plurality of light reflectors
  • said photosensing means is responsive to light reflected from said selected light reflector when said selected light reflector is in said second position.
  • Apparatus for controlling the concentration of multicomponent developer material set forth in claim 8 further comprising:
US00209042A 1971-12-17 1971-12-17 Automatic toner concentration control system Expired - Lifetime US3756192A (en)

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US20904271A 1971-12-17 1971-12-17

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US (1) US3756192A (de)
JP (1) JPS5213935B2 (de)
CA (1) CA1013806A (de)
DE (1) DE2257033C3 (de)
FR (1) FR2165421A5 (de)
GB (1) GB1376359A (de)
IT (1) IT967829B (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3869910A (en) * 1973-06-18 1975-03-11 Xerox Corp Diagnostic test device for developer materials
US3872824A (en) * 1972-02-22 1975-03-25 Dyk Research Corp Van Xerographic toner concentration control apparatus
US3911861A (en) * 1973-12-03 1975-10-14 Addressograph Multigraph Programmable toner concentration control
US3924462A (en) * 1971-08-06 1975-12-09 Hoechst Ag Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine
US3926145A (en) * 1974-03-04 1975-12-16 Honeywell Inf Systems Toner concentration detector
US3999512A (en) * 1974-09-25 1976-12-28 Xerox Corporation Electrostatic development system with passive storage capacity
EP0037711A2 (de) * 1980-04-07 1981-10-14 Xerox Corporation Verfahren und Vorrichtung zur Überwachung eines Kopiergerätes
US4369733A (en) * 1979-11-07 1983-01-25 Ricoh Company, Ltd. Toner concentration control apparatus
US4389972A (en) * 1979-08-04 1983-06-28 Ricoh Company, Ltd. Toner concentration control apparatus
US4506973A (en) * 1983-06-20 1985-03-26 Eastman Kodak Company Toner concentration monitoring apparatus located behind a transparent photoconductor
US4553033A (en) * 1983-08-24 1985-11-12 Xerox Corporation Infrared reflectance densitometer
US20140016977A1 (en) * 2012-07-10 2014-01-16 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4032227A (en) * 1976-01-15 1977-06-28 International Business Machines Corporation Toner concentration control apparatus
JPS53103736A (en) * 1977-02-23 1978-09-09 Ricoh Co Ltd Auto-bias development for xerographic copying machine
JPS546561A (en) * 1977-06-16 1979-01-18 Toshiba Corp Developer concentration controller
US4273843A (en) * 1978-06-12 1981-06-16 Konishiroku Photo Industry Co., Ltd. Method of detecting toner concentration in electrophotographic copying machine
JPS5519543A (en) * 1978-07-31 1980-02-12 Nippon Carbon Co Ltd Preparation of frp screw
NL7808419A (nl) * 1978-08-14 1980-02-18 Oce Nederland Bv Tonerconcentratieregeling.
JPS5624376A (en) * 1979-08-04 1981-03-07 Ricoh Co Ltd Toner concentration control unit of developer
JPS6056069A (ja) * 1983-09-06 1985-04-01 Matsushita Electric Ind Co Ltd 薄膜形成装置
JPS6089673U (ja) * 1983-11-25 1985-06-19 ソニー株式会社 テ−プカセツト

Citations (9)

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US2589414A (en) * 1947-09-23 1952-03-18 Gen Motors Corp Radiant energy transmission and reflection analyzer with adjustable filter
US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3233781A (en) * 1963-05-08 1966-02-08 Savin Business Machines Corp Toner control system
US3399652A (en) * 1967-06-14 1968-09-03 Addressograph Multigraph Automatic toner concentrate detector
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
US3609047A (en) * 1970-03-02 1971-09-28 Xerox Corp Single beam photometer system wherein the absorbance of a sample is determined relative to a reference
US3610205A (en) * 1968-10-17 1971-10-05 Continental Can Co Apparatus for measuring and controlling mixture content
US3669547A (en) * 1970-09-14 1972-06-13 Bell Telephone Labor Inc Optical spectrometer with transparent refracting chopper
US3677652A (en) * 1971-06-15 1972-07-18 Gte Sylvania Inc Fluid analyzer apparatus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2589414A (en) * 1947-09-23 1952-03-18 Gen Motors Corp Radiant energy transmission and reflection analyzer with adjustable filter
US2956487A (en) * 1955-03-23 1960-10-18 Rca Corp Electrostatic printing
US3233781A (en) * 1963-05-08 1966-02-08 Savin Business Machines Corp Toner control system
US3399652A (en) * 1967-06-14 1968-09-03 Addressograph Multigraph Automatic toner concentrate detector
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
US3610205A (en) * 1968-10-17 1971-10-05 Continental Can Co Apparatus for measuring and controlling mixture content
US3609047A (en) * 1970-03-02 1971-09-28 Xerox Corp Single beam photometer system wherein the absorbance of a sample is determined relative to a reference
US3669547A (en) * 1970-09-14 1972-06-13 Bell Telephone Labor Inc Optical spectrometer with transparent refracting chopper
US3677652A (en) * 1971-06-15 1972-07-18 Gte Sylvania Inc Fluid analyzer apparatus

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924462A (en) * 1971-08-06 1975-12-09 Hoechst Ag Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine
US3872824A (en) * 1972-02-22 1975-03-25 Dyk Research Corp Van Xerographic toner concentration control apparatus
US3869910A (en) * 1973-06-18 1975-03-11 Xerox Corp Diagnostic test device for developer materials
US3911861A (en) * 1973-12-03 1975-10-14 Addressograph Multigraph Programmable toner concentration control
US3926145A (en) * 1974-03-04 1975-12-16 Honeywell Inf Systems Toner concentration detector
US3999512A (en) * 1974-09-25 1976-12-28 Xerox Corporation Electrostatic development system with passive storage capacity
US4389972A (en) * 1979-08-04 1983-06-28 Ricoh Company, Ltd. Toner concentration control apparatus
US4369733A (en) * 1979-11-07 1983-01-25 Ricoh Company, Ltd. Toner concentration control apparatus
EP0037711A3 (en) * 1980-04-07 1982-07-21 Xerox Corporation Method and apparatus for controlling a reproduction machine
EP0037711A2 (de) * 1980-04-07 1981-10-14 Xerox Corporation Verfahren und Vorrichtung zur Überwachung eines Kopiergerätes
US4506973A (en) * 1983-06-20 1985-03-26 Eastman Kodak Company Toner concentration monitoring apparatus located behind a transparent photoconductor
US4553033A (en) * 1983-08-24 1985-11-12 Xerox Corporation Infrared reflectance densitometer
US20140016977A1 (en) * 2012-07-10 2014-01-16 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus
US9423760B2 (en) * 2012-07-10 2016-08-23 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus

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CA1013806A (en) 1977-07-12
DE2257033B2 (de) 1980-01-10
IT967829B (it) 1974-03-11
JPS5213935B2 (de) 1977-04-18
JPS4869527A (de) 1973-09-21
FR2165421A5 (de) 1973-08-03
DE2257033C3 (de) 1980-09-04
DE2257033A1 (de) 1973-06-20
GB1376359A (en) 1974-12-04

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