EP0031564A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Quality control copying apparatus
Assignee: Toshiba Corp
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Filing: 1980-12-19
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Granted: —
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Expires: 2000-12-19
Abstract
Abstract The present invention concerns copying apparatus which automatically controls the quality of copies. The copying apparatus includes a density detector for detecting the frequency of occurrence of density values along a scanning line of a document to be copied, i.e., the frequency distribution of density values is determined. When the frequency distribution has at least three maxima, a smoothing device smoothes the frequency distribution via a predetermined filter function till the frequency distribution has one or two maxima. In the event the frequency distribution has one or two maxima, a density detecting device detects at least one density value according to a maximum or minimum value of the frequency distribution. A control device then controls the copy quality of a reproduced image according to the density value.
Inventors
- 👤 Shuzo Hirahara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 14:54
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/50; G03G15/5025
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
126 words
An automatic quality control copying apparatus comprising: frequency detecting means for detecting the frequency distribution of the density of a document, the frequency distribution meaning the frequency of occurrence of each density value of the document; smoothing means for smoothing the frequency distribution when the frequency distribution has at least three maxima, said smoothing means executing a predetermined filter function till the frequency distribution has one or two maxima; density detecting means responsive to said frequency detecting means and said smoothing means for detecting at least one density value according to a maximum or minimum value of the frequency distribution when the frequency distribution has one or two maxima; and control means for controlling the quality of a reproductive image according to the detected density value.
Claim 2
Dependent Claim
126 words
An automatic quality control copying apparatus comprising: frequency detecting means for detecting the frequency distribution of the density of a document, the frequency distribution meaning the frequency of occurrence of each density value of the document; smoothing means for smoothing the frequency distribution when the frequency distribution has at least three maxima, said smoothing means executing a predetermined filter function till the frequency distribution has one or two maxima; density detecting means responsive to said frequency detecting means and said smoothing means for detecting at least one density value according to a maximum or minimum value of the frequency distribution when the frequency distribution has one or two maxima; and control means for controlling the quality of a reproductive image according to the detected density value.
Claim 3
Dependent Claim
31 words
An automatic quality control copying apparatus according to claim 1 wherein said density detecting means detects two density value corresponding to two maximum values when the frequency distribution has two maxima.
Claim 4
Dependent Claim
24 words
An automatic quality control copying apparatus according to claim 2 wherein said density detecting means calculates the harmonic mean of the two density values.
Claim 5
Dependent Claim
27 words
An automatic quality control copying apparatus according to claim 1 wherein said smoothing means smoothes the frequency distribution by using a weighting function having binomial distribution coefficients.
Claim 6
Dependent Claim
37 words
An automatic quality control copying apparatus according to claim 1 further comprising a first lamp to expose a photosensitive material and said control means controls the exposure time of said first lamp according to the density value.
Claim 7
Dependent Claim
43 words
An automatic quality control copying apparatus according to claim 1 further comprising a developing device to develop a latent image formed on a photosensitive material and said control means controls a voltage value supplied to said developing device according to the density value.
Claim 8
Dependent Claim
30 words
An automatic quality control copying apparatus according to claim 5 wherein said control means controls the exposure time by phase control of an a.c. voltage supplied to said first lamp.
Claim 9
Dependent Claim
37 words
An automatic quality control copying apparatus according to claim 5 wherein said frequency detecting means comprises a second lamp, said frequency detecting means detecting the frequency distribution of each document before copying by using said second lamp.
Claim 10
Dependent Claim
36 words
An automatic quality control copying apparatus according to claim 5 wherein said frequency detecting means stores the frequency of each density value in order by using said first lamp and detects the frequency distribution before copying.
Claim 11
Dependent Claim
149 words
An automatic quality control copying apparatus comprising: frequency detecting means for detecting the frequency distribution of the density of a document, the frequency distribution meaning the frequency of occurrence of value of the document; smoothing means for smoothing the frequency distribution when the frequency distribution has at least three maxima; said smoothing means executing a predetermined filter function till the frequency distribution has one or two maxima; variance calculating means for calculating a variance value about a maximum value in the frequency distribution having one or two maxima; density detecting means responsive to said frequency detecting means and said smoothing means for detecting at least one density value according to a maximum or minimum value of the frequency distribution when the frequency distribution has one or two maxima; and control means for controlling the quality of a reproductive image according to the detected density value and the variance value.
Claim 12
Dependent Claim
149 words
An automatic quality control copying apparatus comprising: frequency detecting means for detecting the frequency distribution of the density of a document, the frequency distribution meaning the frequency of occurrence of value of the document; smoothing means for smoothing the frequency distribution when the frequency distribution has at least three maxima; said smoothing means executing a predetermined filter function till the frequency distribution has one or two maxima; variance calculating means for calculating a variance value about a maximum value in the frequency distribution having one or two maxima; density detecting means responsive to said frequency detecting means and said smoothing means for detecting at least one density value according to a maximum or minimum value of the frequency distribution when the frequency distribution has one or two maxima; and control means for controlling the quality of a reproductive image according to the detected density value and the variance value.
Claim 13
Dependent Claim
31 words
An automatic quality control copying apparatus according to claim 10 wherein said density detecting means detects two density values according to two maximum values when the frequency distribution has two maxima.
Claim 14
Dependent Claim
26 words
An automatic quality control copying apparatus according to claim 10 wherein said density detecting means further calculates the harmonic mean value of the two density values.
Claim 15
Dependent Claim
27 words
An automatic quality control copying apparatus according to claim 10 wherein said smoothing means smoothes the frequency distribution by using a weighting function having binomial distribution coefficients.
Claim 16
Dependent Claim
37 words
An automatic quality control copying apparatus according to claim 10 further comprising a first lamp to expose a photosensitive material and said control means controls the exposure time of said first lamp according to the density value.
Claim 17
Dependent Claim
44 words
An automatic quality control copying apparatus according to claim 14 further comprising a developing device to develop a latent image formed on a photosensitive material and said control means and controls a voltage value supplied to said developing device according to the density value.
Claim 18
Dependent Claim
30 words
An automatic quality control copying apparatus according to claim 14 wherein said control means controls the exposure time by phase control of an a.c. voltage supplied to said first lamp.
Claim 19
Dependent Claim
37 words
An automatic quality control copying apparatus according to claim 14 wherein said frequency detecting means comprises a second lamp, said frequency detecting means detecting the frequency distribution of each document before copying by using said second lamp.
Claim 20
Dependent Claim
36 words
An automatic quality control copying apparatus according to claim 14 wherein said frequency detecting means stores the frequency of each density value in order by using said first lamp and detects the frequency distribution before copying.
References Cited (Backward Citations)
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