US5298944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Testing image density to control toner concentration and dynamic range in a digital copier
Assignee: Ricoh Co Ltd
•
Filing: 1993-07-19
•
Granted: 1994-03-29
•
Expires: 2013-07-19
Abstract
Abstract A developing system of the type using a two-component developer and capable of reproducing image densities and halftone images stably with no regard to changes in ambient conditions and aging. At least two toner image patterns each having a different toner density are formed on a photoconductive element. The amounts of toner deposited on the individual patterns are sensed by a photosensor, while the supply of toner to a developer and the dynamic range of a latent image are controlled in combination in response to the output of the photosensor.
Inventors
- 👤 Noboru Sawayama
- 👤 Takayuki Maruta
- 👤 Mitsuo Hasebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:56
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/50; G03G15/5033; G03G15/5041; G03G2215/00; G03G2215/00025; G03G2215/00029; G03G2215/00033; G03G2215/00037; G03G2215/00042
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
196 words
In an image forming system comprising charging means for uniformly charging a surface of a photoconductive element to a predetermined potential, and exposing means for exposing said surface of said photoconductive element to a light image to electrostatically form a latent image on said surface, a developing system for developing said latent image to produce a toner image, comprising: sensor pattern forming means for forming two toner image patterns on the photoconductive element, each of said two toner image patterns having a different particular toner density on the photoconductive element; a photosensor for sensing toner densities of toner deposited on said two toner image patterns; and control means for determining a difference between the sensed toner densities of toner deposited on the two toner image patterns, for variably controlling an amount of toner to be supplied to a developer and for variably controlling a dynamic range of a latent image such that the toner density difference between said two toner image patterns is maintained at a predetermined difference value, wherein said dynamic range represents a difference between maximum and minimum values of a surface potential of said photoconductive element on which said latent images are formed.
Claim 2
Dependent Claim
196 words
In an image forming system comprising charging means for uniformly charging a surface of a photoconductive element to a predetermined potential, and exposing means for exposing said surface of said photoconductive element to a light image to electrostatically form a latent image on said surface, a developing system for developing said latent image to produce a toner image, comprising: sensor pattern forming means for forming two toner image patterns on the photoconductive element, each of said two toner image patterns having a different particular toner density on the photoconductive element; a photosensor for sensing toner densities of toner deposited on said two toner image patterns; and control means for determining a difference between the sensed toner densities of toner deposited on the two toner image patterns, for variably controlling an amount of toner to be supplied to a developer and for variably controlling a dynamic range of a latent image such that the toner density difference between said two toner image patterns is maintained at a predetermined difference value, wherein said dynamic range represents a difference between maximum and minimum values of a surface potential of said photoconductive element on which said latent images are formed.
Claim 3
Dependent Claim
38 words
A system as claimed in claim 1, wherein said control means controls the dynamic range such that when the toner density difference is lower than said predetermined value, the dynamic range is reduced to increase the toner density.
Claim 4
Dependent Claim
28 words
A system as claimed in claim 1, wherein said control means changes the dynamic range of a latent image by changing a charging potential of the charging means.
Claim 5
Dependent Claim
30 words
A system as claimed in claim 1, wherein said control means changes the dynamic range of a latent image by changing a quantity of exposing light of the exposing means.
Claim 6
Dependent Claim
28 words
A system as claimed in claim 1, wherein said sensor pattern forming means develops each of a same kind of latent image patterns by a difference developing bias.
Claim 7
Dependent Claim
27 words
A system as claimed in claim 1, wherein said sensor pattern forming means develops each of different kinds of latent image patterns by a same developing bias.
Claim 8
Dependent Claim
47 words
A system as claimed in claim 1, wherein the toner image patterns comprise two kinds of line patterns produced by controlling an amount of exposure, and the dynamic range is variably controlled such that the difference in density between the two kinds of line patterns remains constant.
Claim 9
Dependent Claim
28 words
A system as claimed in claim 7, wherein the two kinds of line patterns are a line pattern of maximum density and a line pattern of medium density.
Claim 10
Dependent Claim
35 words
A system as claimed in claim 7, wherein the toner image patterns further comprise a solid pattern of medium density, and the toner concentration (toner supplement) is controlled on the basis of the solid pattern.
Claim 11
Dependent Claim
184 words
A developing method for an image forming system comprising the steps of: (a) uniformly charging a surface of a photoconductive element to a predetermined potential; (b) exposing the surface of the photoconductive element to a light image to electrostatically form a latent image on the surface; (c) forming two toner image patterns on the surface of the photoconductive element, each of said two toner image patterns having a different particular toner density; (d) sensing toner densities of toner deposited on the two toner image patterns; (e) determining a difference between the sensed toner densities of toner deposited on the two toner image patterns and controlling an amount of toner to be supplied to a developer such that the sensed amount of toner coincides with a predetermined amount; and (f) variably controlling a dynamic range of a latent image such that the toner density difference between the two toner image patterns is maintained at a predetermined difference value, wherein said dynamic range represents a difference between maximum and minimum values of a surface potential of said photoconductive element on which said latent images are formed.
Claim 12
Dependent Claim
184 words
A developing method for an image forming system comprising the steps of: (a) uniformly charging a surface of a photoconductive element to a predetermined potential; (b) exposing the surface of the photoconductive element to a light image to electrostatically form a latent image on the surface; (c) forming two toner image patterns on the surface of the photoconductive element, each of said two toner image patterns having a different particular toner density; (d) sensing toner densities of toner deposited on the two toner image patterns; (e) determining a difference between the sensed toner densities of toner deposited on the two toner image patterns and controlling an amount of toner to be supplied to a developer such that the sensed amount of toner coincides with a predetermined amount; and (f) variably controlling a dynamic range of a latent image such that the toner density difference between the two toner image patterns is maintained at a predetermined difference value, wherein said dynamic range represents a difference between maximum and minimum values of a surface potential of said photoconductive element on which said latent images are formed.
Claim 13
Dependent Claim
33 words
A developing method as claimed in claim 10, wherein step (f) comprises (g) reducing the dynamic range to increase the toner density when the toner density difference is lower than said predetermined value.
Claim 14
Dependent Claim
26 words
A developing method as claimed in claim 10, wherein step (f) comprises (g) changing the dynamic range of a latent image by changing a charging potential.
Claim 15
Dependent Claim
28 words
A developing method as claimed in claim 10, wherein step (f) comprises (g) changing the dynamic range of a latent image by changing a quantity of exposing light.
Claim 16
Dependent Claim
28 words
A developing method as claimed in claim 10, wherein step (c) comprising (g) developing each of a same kind of latent image patterns by a different developing bias.
Claim 17
Dependent Claim
27 words
A developing method as claimed in claim 10, wherein step (c) comprises (g) developing each of different kinds of latent image patterns by a same developing bias.
References Cited (Backward Citations)
US4248527A
Cited
US4313671A
Cited
US4277162A
Cited
US4350435A
Cited
US4348099A
Cited
US4572654A
Cited
US4466731A
Cited
US4888636A
Cited
US4647184A
Cited
US4816863A
Cited
US4786924A
Cited
US4962407A
Cited
US4999673A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-28 | 1997-09-27 | 1998-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-28 | 2001-09-27 | 2002-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-28 | 2005-09-27 | 2006-03-29 | $7700.00 | Window Closed / Lapsed |