Abstract In an image area measuring apparatus wherein an image bearing surface of a lithographic printing plate is divided into a plurality of zones and photographed with a television camera to produce analog image signals which are converted into digital signals to obtain a measured value, the image area of each zone is calculated based on the measured value and a quantity of printing ink is determined according to the image area, there is provided a method of processing an image signal including the steps of preparing a first conversion table for 100% dot ratio, and a second conversion table for other percentage of dot ratios, determining the quantity of printing ink from the first conversion table at the time of printing an image having 100% dot ratio, and determining the quantity of the ink from the second conversion table at the time of printing an image having a dot ratio other than 100%.
Inventors
👤 Teruo Tsunoda
👤 Ryoichi Kokawa
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-29 12:48
CPC Classifications
B; B41; B41F; B41F33/00; B41F33/0027
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
176 words
In an image area measuring apparatus of the type wherein an image bearing surface of a lithographic printing plate is divided into a plurality of zones and photographed with a television camera to produce an analog image signal which is converted into a digital signal to obtain a measured value, the image area of each zone is calculated based on the measured value and a quantity of printing ink supplied at the time of printing to said lithographic printing plate is determined according to said image area, a method of processing an image signal comprising the steps of preparing a first conversion table for zones having at least a portion with 100% dot ratio and a second conversion table for other percentage of dot ratios, determining the quantity of printing ink from said first conversion table at the time of printing an image having a 100% dot ratio portion, and determining the quantity of the printing ink from said second conversion table at the time of printing an image having a dot ratio other than 100%.
Claim 2
Dependent Claim
176 words
In an image area measuring apparatus of the type wherein an image bearing surface of a lithographic printing plate is divided into a plurality of zones and photographed with a television camera to produce an analog image signal which is converted into a digital signal to obtain a measured value, the image area of each zone is calculated based on the measured value and a quantity of printing ink supplied at the time of printing to said lithographic printing plate is determined according to said image area, a method of processing an image signal comprising the steps of preparing a first conversion table for zones having at least a portion with 100% dot ratio and a second conversion table for other percentage of dot ratios, determining the quantity of printing ink from said first conversion table at the time of printing an image having a 100% dot ratio portion, and determining the quantity of the printing ink from said second conversion table at the time of printing an image having a dot ratio other than 100%.
Claim 3
Dependent Claim
29 words
The method according to claim 1 wherein said lithographic printing plate is substituted by a correction plate having a uniform light reflectivity at the time of correcting nonuniform brightness.