US4539279A
Expired / Lapsed
US
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Image density control method
Assignee: Ricoh Co Ltd
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Filing: 1983-11-07
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Granted: 1985-09-03
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Expires: 2003-11-07
Abstract
Abstract An image density control method for an electrophotographic apparatus is disclosed which prepares a white pattern region and a black pattern region on a photoconductive element whose electrostatic latent images are far different from each other in potential. Values relating to image densities individually associated with the two pattern regions are sensed and, based on the sensed values, parameters relating to image processing which effect image density are controlled. When any of the sensed values does not lie in a predetermined range, it is suitably compensated.
Inventors
- 👤 Kazuo Murai
- 👤 Yutaka Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:12
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/043
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
147 words
A method of controlling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element; (b) sensing a value relating to an image density in each of the two pattern regions; (c) compensating the sensed value relating to the image density in each of the pattern regions when said value is out of a predetermined range; and (d) controlling an image density parameter relating to image precessing which has influence on image density, in response to the values relating to the image densities which are representative of the two pattern regions respectively; step (c) comprising a step of (e) interrupting a control over the image density parameter.
Claim 2
Independent Claim
147 words
A method of controlling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element; (b) sensing a value relating to an image density in each of the two pattern regions; (c) compensating the sensed value relating to the image density in each of the pattern regions when said value is out of a predetermined range; and (d) controlling an image density parameter relating to image precessing which has influence on image density, in response to the values relating to the image densities which are representative of the two pattern regions respectively; step (c) comprising a step of (e) interrupting a control over the image density parameter.
Claim 3
Dependent Claim
32 words
A method as claimed in claim 1, in which step (a) comprises a step of (e) defining the two pattern regions by scanning white and black optical marks by means of light.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 1, in which step (a) comprises a step of (e) defining the two pattern regions by a charge-uncharge control over a charger.
Claim 5
Dependent Claim
29 words
A method as claimed in claim 1, in which step (a) comprises a step of (e) defining the two pattern regions by an on-off control over an exposing lamp.
Claim 6
Dependent Claim
29 words
A method as claimed in claim 1, in which step (a) comprises a step of (e) defining the two pattern regions by an on-off control over an erase lamp.
Claim 7
Dependent Claim
35 words
A method as claimed in claim 1, in which step (a) comprises a step of (e) defining the two pattern regions by controlling a bias voltage for development which is applied to a developing roller.
Claim 8
Dependent Claim
70 words
A method as claimed in claim 1, in which the values relating to the image densities representable of the two pattern regions in step (b) comprise at least one of values of surface potentials in the two pattern regions before development, values of surface potentials in the two pattern regions after development and values of image densities in the two pattern regions which are transferred to a sheet of paper.
Claim 9
Dependent Claim
21 words
A method as claimed in claim 1, in which step (c) further comprises a step of (f) energizing a display lamp.
Claim 10
Dependent Claim
21 words
A method as claimed in claim 1, in which step (c) further comprises a step of (f) interrupting a recording operation.
Claim 11
Dependent Claim
55 words
A method as claimed in claim 1, in whcih the image density parameter in step (d) comprises at least one of a toner concentration in a developer, a charge voltage applied to a charger, a bias voltage for development, an amount of exposure, a transfer potential, and a quantity of toner supply to the developer.
Claim 12
Dependent Claim
22 words
A method as claimed in claim 1, in which the pattern regions comprise a white pattern region and a black pattern region.
Claim 13
Dependent Claim
46 words
A method as claimed in claim 11, in which the predetermined range of the value relating to the image density in the white pattern region is between 2.5 V and 4.8 V and that in the black pattern region is between 0.5 V and 2.3 V.
Claim 14
Independent Claim
122 words
A method of controlling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner in a developer, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element; (b) sensing a value relating to an image density in each of the two pattern regions; (c) performing primary toner supply to the developer in accordance with a number of electrostatic images developed by the toner; and (d) performing secondary toner supply to the developer in response to the values relating to the image densities which are representative of the two pattern regions respectively.
Claim 15
Independent Claim
122 words
A method of controlling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner in a developer, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element; (b) sensing a value relating to an image density in each of the two pattern regions; (c) performing primary toner supply to the developer in accordance with a number of electrostatic images developed by the toner; and (d) performing secondary toner supply to the developer in response to the values relating to the image densities which are representative of the two pattern regions respectively.
Claim 16
Independent Claim
176 words
A method of controling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element, the pattern regions comprising a white pattern region and a black pattern region; (b) sensing an image density in each of the two pattern regions; (c) producing values relating to the image densities by multiplying the sensed image density of the black pattern region by a constant value which is predetermined in such a manner that the value relating to the image density of the black pattern region will be approximately equal to the value relating to the image density of the white pattern region; and (d) controlling an image density parameter relating to image processing which has influenece on image density, in response to the values relating to the image densities which are representative of the two pattern regions respectively.
Claim 17
Independent Claim
176 words
A method of controling a density of an image formed by developing an electrostatic image on a photoconductive element by means of a toner, said method comprising the steps of: (a) providing at least two regions for independent test patterns which are different from each other as latent images electrostatically formed on a photoconductive element, the pattern regions comprising a white pattern region and a black pattern region; (b) sensing an image density in each of the two pattern regions; (c) producing values relating to the image densities by multiplying the sensed image density of the black pattern region by a constant value which is predetermined in such a manner that the value relating to the image density of the black pattern region will be approximately equal to the value relating to the image density of the white pattern region; and (d) controlling an image density parameter relating to image processing which has influenece on image density, in response to the values relating to the image densities which are representative of the two pattern regions respectively.
References Cited (Backward Citations)
US4313671A
Cited
US4372672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |