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US5680222A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for preparing color screens in a halftone image

Assignee: Megadot Systems Ltd
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Filing: 1995-07-18
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Granted: 1997-10-21
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Expires: 2015-07-18
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Abstract

Abstract The dot patterns which may be used to reduce dot gain and moire effects in halftone images involve printing areas which have inwardly curved edges and variable elongation. Colored images having screens which use these patterns may be printed with the screens at 45° relative angular separations. Alternatively the dot patterns may be regarded as reversed variable oval patterns with varying elongation of the generally oval shaped non-printing areas.

Inventors

  • 👤 William Frederick Ashworth

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 12:16
CPC Classifications
G; G03; G03F; G03F5/00; H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4058; H04N1/46; H04N1/52

Claims Analysis

Total Claims: 29
Claim 1
Independent Claim 99 words
A method of preparing halftone screens prior to printing a colored image comprising the steps of: (a) receiving information representing color and tone variation in a previously recorded scene; (b) processing the information to create halftone screens representing primary colors in the scene, by 1) creating cyan and magenta screens having printing areas with inwardly curved edges, and 2) orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen; and (c) producing halftone screens representing primary colors in a form appropriate for subsequent printing of the colored image.
Claim 2
Independent Claim 99 words
A method of preparing halftone screens prior to printing a colored image comprising the steps of: (a) receiving information representing color and tone variation in a previously recorded scene; (b) processing the information to create halftone screens representing primary colors in the scene, by 1) creating cyan and magenta screens having printing areas with inwardly curved edges, and 2) orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen; and (c) producing halftone screens representing primary colors in a form appropriate for subsequent printing of the colored image.
Claim 3
Dependent Claim 33 words
A method according to claim 1, further comprising the step of: creating the cyan and magenta screens having printing areas in light tones formed as dots which are increasingly elongated with darkening tones.
Claim 4
Dependent Claim 21 words
A method according to claim 2, further comprising: joining the dots in two distinct stages as tone darkens or lightens respectively.
Claim 5
Dependent Claim 33 words
A method according to claim 1, further comprising the step of: creating the cyan and magenta screens having non-printing areas in dark tones formed as dots which are increasingly elongated with lightening tones.
Claim 6
Dependent Claim 21 words
A method according to claim 4, further comprising: joining the dots in two distinct stages as tone darkens or lightens respectively.
Claim 7
Dependent Claim 20 words
A method according to claim 1, further comprising the step of: creating cyan and magenta screens which are relatively offset.
Claim 8
Dependent Claim 29 words
A method according to claim 1, further comprising the step of: creating cyan and magenta screens having printing areas which in light tones are inwardly curved on every edge.
Claim 9
Dependent Claim 23 words
A method according to claim 1; further comprising the step of: creating every primary color screen having printing areas with inwardly curved edges.
Claim 10
Dependent Claim 22 words
A method according to claim 1, further comprising the step of: creating a black screen having printing areas with inwardly curved edges.
Claim 11
Dependent Claim 22 words
A method according to claim 9, further comprising the step of: orienting yellow and black screens at approximately 90° to each other.
Claim 12
Dependent Claim 29 words
A method according to claim 9, further comprising the step of: orienting the black screen at an angle which is approximately a multiple of 45° to any other screen.
Claim 13
Dependent Claim 35 words
A method according to claim 11, further comprising the step of: creating the black screen with a screen ruling which is reduced by a factor of approximately 0.71 relatively to the cyan and magenta screens.
Claim 14
Dependent Claim 23 words
A method according to claim 1; further comprising the step of: orienting the cyan and magenta screens at approximately 90° to each other.
Claim 15
Independent Claim 72 words
A method of printing halftone screens to form a colored image, comprising the steps of: (a) receiving information representing primarily colored halftone screens, wherein cyan and magenta screens have printing areas with inwardly curved edges; (b) orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen; and (b) superimposing and printing the oriented primary color screens to form a colored image.
Claim 16
Independent Claim 72 words
A method of printing halftone screens to form a colored image, comprising the steps of: (a) receiving information representing primarily colored halftone screens, wherein cyan and magenta screens have printing areas with inwardly curved edges; (b) orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen; and (b) superimposing and printing the oriented primary color screens to form a colored image.
Claim 17
Dependent Claim 54 words
A method according to claim 14, further comprising the steps of: receiving information representing a black halftone screen, orienting the black halftone screen at an angle which is approximately a multiple of 45° to any other screen, and printing the oriented black color screen with the primary color screens to form the colored image.
Claim 18
Dependent Claim 108 words
A computer controlled apparatus for preparing halftone screens representing a colored image, comprising: means for scanning a previously recorded scene to produce information representing color and tone variation in the scene, means for processing the information to create halftone screens representing the primary colors and black tone variation in the scene; and means for producing the halftone screens in or on an output medium; wherein the means for processing includes means for creating cyan and magenta screens having printing areas with inwardly curved edges, and means for orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen.
Claim 19
Dependent Claim 108 words
A computer controlled apparatus for preparing halftone screens representing a colored image, comprising: means for scanning a previously recorded scene to produce information representing color and tone variation in the scene, means for processing the information to create halftone screens representing the primary colors and black tone variation in the scene; and means for producing the halftone screens in or on an output medium; wherein the means for processing includes means for creating cyan and magenta screens having printing areas with inwardly curved edges, and means for orienting each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen.
Claim 20
Dependent Claim 36 words
Apparatus according to claim 16, wherein the means for processing further comprises means for producing tone variation in the primary color halftone screens by creating printing areas which vary in elongation between light and dark tones.
Claim 21
Dependent Claim 37 words
Apparatus according to claim 16, wherein the means for processing further comprises includes means for producing tone variation in the primary color halftone screens by creating non-printing areas which vary in elongation between dark and light tones.
Claim 22
Dependent Claim 109 words
A computer controlled apparatus for preparing halftone screens representing a colored image, comprising: (a) means for receiving information representing color and tone variation in a previously recorded scene; (b) means for processing the information to create halftone screens representing primary colors in the scene; and (c) means for producing halftone screens representing primary colors in a form appropriate for subsequent printing of the colored image; wherein the means for processing includes means for creating cyan and magenta screens having printing areas with inwardly curved edges, and means for orienting: each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen.
Claim 23
Dependent Claim 109 words
A computer controlled apparatus for preparing halftone screens representing a colored image, comprising: (a) means for receiving information representing color and tone variation in a previously recorded scene; (b) means for processing the information to create halftone screens representing primary colors in the scene; and (c) means for producing halftone screens representing primary colors in a form appropriate for subsequent printing of the colored image; wherein the means for processing includes means for creating cyan and magenta screens having printing areas with inwardly curved edges, and means for orienting: each primary color screen at an angle which is approximately a multiple of 45° to any other primary color screen.
Claim 24
Dependent Claim 35 words
Apparatus according to claim 19, wherein the means for processing includes means for producing tone variation in the primary color halftone screens by creating printing areas which vary in elongation between light and dark tones.
Claim 25
Dependent Claim 27 words
Apparatus according to claim 20, wherein the means for processing includes means for joining the printing areas in two distinct stages as tone darkness or lightens respectively.
Claim 26
Dependent Claim 35 words
Apparatus according to claim 19, wherein the means for processing includes means for producing tone variation in the primary color halftone screens by creating non-printing areas which vary in elongation between dark and light tones.
Claim 27
Dependent Claim 27 words
Apparatus according to claim 22, wherein the means for processing includes means for joining the non-printing areas in two distinct stages as tone darkness or lightens respectively.
Claim 28
Dependent Claim 48 words
A process of preparing a halftone image wherein tone variation in cyan and magenta screens is produced by creating the steps of: creating printing areas which have inwardly curved edges; and placing each primary color screen at an angle of approximately 45° to any other primary color screen.
Claim 29
Dependent Claim 48 words
A process of preparing a halftone image wherein tone variation in cyan and magenta screens is produced by creating the steps of: creating printing areas which have inwardly curved edges; and placing each primary color screen at an angle of approximately 45° to any other primary color screen.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-10-20 2001-04-21 2001-10-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-10-20 2005-04-21 2005-10-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-10-20 2009-04-21 2009-10-21 $7700.00 Window Closed / Lapsed

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