US3924462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring the toner concentration of a developer circulating in an electrophotographic reproduction machine
Assignee: Hoechst AG
•
Filing: 1972-08-07
•
Granted: 1975-12-09
•
Expires: 1992-08-07
Abstract
Abstract A method of measuring or measuring and controlling the toner concentration of a developer circulating in an electrophotographic reproduction machine wherein a test charge pattern based on toner concentration is formed independent of the photoconductor, the test charge pattern is developed together with the photoconductor exposed to produce an image, optical properties of the developed test charge pattern are measured and toner is added to the developer based upon the measurement. An apparatus including electrodes for producing a test charge pattern which are so arranged in the electrophotographic reproduction machine that together with the photoconductor they can be moved past the operative devices in the electrophotographic cycle, sliding contact rings and/or wiper contacts for applying potential to the electrodes from a voltage source and comparative light beams from the same source for carrying out the measurement of a developed test charge pattern. One of the beams is affected by the developed test charge pattern while the other is an unaffected reference beam. The apparatus also may include a controlling device for the addition of toner to the developer which is responsive to the optical property of the test charge pattern.
Inventors
- 👤 Hartmut Bock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:13
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0848; G03G15/0849; G03G15/0855; G03G15/0887; G03G15/0891; G03G15/50; G03G15/5033; G03G15/5041
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
180 words
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 photoconductor''s 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.
Claim 2
Independent Claim
180 words
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 photoconductor''s 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.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein said common electrical potential is so applied to the electrodes that the electrical potential set up in the various zones on the insulating layer either remains the same or decreases in absolute value.
Claim 4
Independent Claim
153 words
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, b. 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 photoconductor''s properties and treatment and of the other parameters of the electrophotographic reproduction cycle, and c. 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.
Claim 5
Independent Claim
153 words
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, b. 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 photoconductor''s properties and treatment and of the other parameters of the electrophotographic reproduction cycle, and c. 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.
Claim 6
Dependent Claim
46 words
The method of claim 3, including connecting for the purpose of effecting brief recharging the oppositely disposed electrodes to a capacitor arranged to rotate with them and to make contact with an external fixed voltage source after each revolution of the drum carrier for the photoconductor.
References Cited (Backward Citations)
US2956487A
Cited
US3094049A
Cited
US3129113A
Cited
US3348522A
Cited
US3348521A
Cited
US3233781A
Cited
US3348523A
Cited
US3376853A
Cited
US3376854A
Cited
US3382796A
Cited
US3399652A
Cited
US3409901A
Cited
US3430606A
Cited
US3526338A
Cited
US3527387A
Cited
US3604939A
Cited
US3677222A
Cited
US3682132A
Cited
US3727065A
Cited
US3712203A
Cited
US3659556A
Cited
US3674353A
Cited
US3780299A
Cited
US3756192A
Cited
US3777173A
Cited
US3791744A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |