EP0370271A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of and apparatus for recording halftone images and halftone images produced thereby
Assignee: Dainippon Screen Manufacturing Co Ltd
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Filing: 1989-10-30
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Granted: —
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Expires: 2009-10-30
Abstract
Abstract A printed image (I t4 ) is produced with halftone images for respective color printers while so-called rosette moire and a color shift from an original image are prevented. Halftone dots (H m4 , H c4 , H k4 ) are formed in linear shapes extending in respective prescribed directions, thereby forming parallel lines with respective intervals (d m4 , d c4 , d k4 ). These extensional directions and intervals of parallel lines are so established that they effectively prevent the rosette moire and the color shift.
Inventors
- 👤 Osamu Dainippon Screen Mfg. Co. Ltd Kitagawa
- 👤 Takashi Danippon Screen Mfg. Co. Ltd. Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 12:37
CPC Classifications
B; B41; B41M; B41M5/00; H; H04; H04N; H04N1/00; H04N1/46; H04N1/52; B41M1/00; B41M1/14; B41M1/20; G; G03; G03F; G03F5/00; G03F5/22; H04N1/40; H04N1/405; H04N1/4055; H04N1/4058
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
113 words
A method of recording halftone images to be employed in reproducing a color image, comprising the steps of: (a) preparing at least two sets of image data representing color separation images of said color image, respectively, and (b) producing at least two halftone images as a function of said at least two sets of image data, respectively, while setting a common screen pitch and a common screen angle to said at least two halftone images, and forming halftone dot elements in each of said at least two halftone images in a linear shape extending in a prescribed extensional direction different from extensional directions in the rest of said at least two halftone images.
Claim 2
Independent Claim
113 words
A method of recording halftone images to be employed in reproducing a color image, comprising the steps of: (a) preparing at least two sets of image data representing color separation images of said color image, respectively, and (b) producing at least two halftone images as a function of said at least two sets of image data, respectively, while setting a common screen pitch and a common screen angle to said at least two halftone images, and forming halftone dot elements in each of said at least two halftone images in a linear shape extending in a prescribed extensional direction different from extensional directions in the rest of said at least two halftone images.
Claim 3
Dependent Claim
69 words
A method in accordance with claim 1, wherein said halftone dot elements have isolated shapes in each of said at least two halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said at least two halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 4
Dependent Claim
92 words
A method in accordance with claim 1, wherein said at least two halftone images include first to third halftone images, halftone dot centers of each of said first to third halftone images form a lattice in the shape of a paralleleogram, two extensional directions of halftone dot elements in said respective first and second halftone images agree with directions of two adjacent sides of said parallelogram, respectively, and an extensional direction of halftone dot elements in said third halftone images agrees with a direction of one of two diagonals of said parallelogram.
Claim 5
Dependent Claim
59 words
A method in accordance with claim 3, wherein said halftone dot centers of each of said first to third halftone images are placed, on an image plane of a reproduced image to be produced with said first to third halftone images, at same positions as said halftone dot centers of the rest of said first to third halftone images.
Claim 6
Dependent Claim
64 words
A method in accordance with claim 3, wherein said halftone dot centers of each of said first to third halftone images are placed, on an image plane of a reproduced image to be produced with said first to third halftone images, at different positions from positions at which said halftone dot centers of the rest of said first to third halftone images are placed.
Claim 7
Dependent Claim
69 words
A method in accordance with claim 3, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 8
Dependent Claim
28 words
A method in accordance with claim 6, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
Claim 9
Independent Claim
225 words
A method of recording halftone images to be employed in reproducing a color image, comprising the steps of: (a) preparing at least three sets of image data representing color separation images of said color image, respectively, and (b) producing at least first to third halftone images as a function of said at least three sets of image data, respectively, while forming halftone dot elements in each of said first to third halftone images in a linear shape extending in a prescribed extensional direction different from extensional directions in the rest of said first to third halftone images, connecting said halftone dot elements with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate in each of said first to third halftone images, thereby forming parallel lines with a regular interval in each of said first to third halftone images, setting said prescribed extensional direction in said third halftone image to agree with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, and setting a pitch of said parallel lines in said third halftone image measured in a direction of a shorter diagonal out of said two diagonals of said minimum parallelogram to be equal to a length of said shorter diagonal.
Claim 10
Independent Claim
225 words
A method of recording halftone images to be employed in reproducing a color image, comprising the steps of: (a) preparing at least three sets of image data representing color separation images of said color image, respectively, and (b) producing at least first to third halftone images as a function of said at least three sets of image data, respectively, while forming halftone dot elements in each of said first to third halftone images in a linear shape extending in a prescribed extensional direction different from extensional directions in the rest of said first to third halftone images, connecting said halftone dot elements with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate in each of said first to third halftone images, thereby forming parallel lines with a regular interval in each of said first to third halftone images, setting said prescribed extensional direction in said third halftone image to agree with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, and setting a pitch of said parallel lines in said third halftone image measured in a direction of a shorter diagonal out of said two diagonals of said minimum parallelogram to be equal to a length of said shorter diagonal.
Claim 11
Dependent Claim
69 words
A method in accordance with claim 8, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 12
Dependent Claim
28 words
A method in accordance with claim 9, wherein differences between intervals of said parallel lines in said first to third halftone images are at most about 20 percent.
Claim 13
Dependent Claim
28 words
A method in accordance with claim 10, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
Claim 14
Independent Claim
184 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least two sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least two sets of prescribed halftone pattern data indicative of a threshold value of image data at each pixel for said at least two sets of image data, respectively, where said at least two sets of prescribed halftone pattern data are indicative of a common screen pitch and a common screen angle, and each of said at least two sets of prescribed halftone pattern data is indicative of halftone dot elements of a linear shape extending in a prescribed extensional direction different from extensional directions represented by the rest of said at least two sets of prescribed halftone pattern data, and (b) means for comparing said at least two sets of prescribed halftone pattern data with said at least two sets of image data with respect to each pixel, respectively, and recording at least two halftone images according to said comparing.
Claim 15
Independent Claim
184 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least two sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least two sets of prescribed halftone pattern data indicative of a threshold value of image data at each pixel for said at least two sets of image data, respectively, where said at least two sets of prescribed halftone pattern data are indicative of a common screen pitch and a common screen angle, and each of said at least two sets of prescribed halftone pattern data is indicative of halftone dot elements of a linear shape extending in a prescribed extensional direction different from extensional directions represented by the rest of said at least two sets of prescribed halftone pattern data, and (b) means for comparing said at least two sets of prescribed halftone pattern data with said at least two sets of image data with respect to each pixel, respectively, and recording at least two halftone images according to said comparing.
Claim 16
Dependent Claim
103 words
An apparatus in accordance with claim 12, wherein said at least two sets of prescrived halftone pattern data include first to third halftone pattern data, halftone dot centers represented by each of said first to third halftone pattern data form a lattice in the shape of a parallelogram, two extensional directions of halftone dot elements represented by said respective first and second halftone pattern data agree with directions of two adjacent sides of said parallelogram, respectively, and an extensional direction of halftone dot elements represented by said third halftone pattern data agrees with a direction of one of two diagonals of said parallelogram.
Claim 17
Dependent Claim
65 words
An apparatus in accordance with claim 13, wherein each of said first to third halftone pattern data is indicative of said halftone dot elements to have isolated shapes at the halftone-dot area rate of at most about 25 percent, and blank areas to have isolated shapes where said halftone dot elements do not exist at the halftone-dot area rate of at lest about 75 percent.
Claim 18
Independent Claim
269 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least three sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least first to third halftone pattern data indicative of a prescribed threshold value of image data at each pixel for said at least three sets of image data, respectively, where each of said at least first to third halftone pattern data is indicative of halftone dot elements which have a linear shape extending in a prescribed extensional direction different from extensional directions represented by the rest of said at least first to third halftone pattern data, and which connect with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate, thereby forming parallel lines with a regular interval, said prescribed extensional direction represented by said third halftone pattern data agrees with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines represented by said first and second halftone pattern data, and a pitch of said parallel lines represented by said third halftone pattern data measured in a direction of a shorter diagonal out of said two diagonal of said minimum parallelogram is equal to a length of said shorter diagonal, and (b) means for comparing said at least first to third halftone pattern data with said at least three sets of image data with respect to each pixel, respectively, and recording at least three halftone images according to said comparing.
Claim 19
Independent Claim
269 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least three sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least first to third halftone pattern data indicative of a prescribed threshold value of image data at each pixel for said at least three sets of image data, respectively, where each of said at least first to third halftone pattern data is indicative of halftone dot elements which have a linear shape extending in a prescribed extensional direction different from extensional directions represented by the rest of said at least first to third halftone pattern data, and which connect with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate, thereby forming parallel lines with a regular interval, said prescribed extensional direction represented by said third halftone pattern data agrees with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines represented by said first and second halftone pattern data, and a pitch of said parallel lines represented by said third halftone pattern data measured in a direction of a shorter diagonal out of said two diagonal of said minimum parallelogram is equal to a length of said shorter diagonal, and (b) means for comparing said at least first to third halftone pattern data with said at least three sets of image data with respect to each pixel, respectively, and recording at least three halftone images according to said comparing.
Claim 20
Dependent Claim
73 words
An apparatus in accordance with claim 15, wherein each of said first to third halftone pattern data is indicative of said halftone dot elemtns to have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas to have isolated shapes where said halftone dot elements do not exist at the halftone-dot area rate of at least 75 percent.
Claim 21
Dependent Claim
30 words
An apparatus in accordance with claim 16, wherein differences between intervals of said parallel lines represented by said first to third halftone pattern data are at most about 20 percent.
Claim 22
Independent Claim
179 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least two sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least two sets of prescribed font data indicative of a shape of a halftone dot depending on a level of a given image data at each pixel for said at least two sets of image data, respectively, where said at least two sets of prescribed font data are indicative of a common screen pitch and a common screen angle, and each of said at least two sets of prescribed font data is indicative of halftone dot elements of a linear shape extending in a prescribed extensional direction different form extensional directions represented by the rest of said at least two sets of prescribed font data, and (b) means for recording at least two halftone images corresponding to said at least two sets of image data as a function of font data supplied from said means (a).
Claim 23
Independent Claim
179 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least two sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least two sets of prescribed font data indicative of a shape of a halftone dot depending on a level of a given image data at each pixel for said at least two sets of image data, respectively, where said at least two sets of prescribed font data are indicative of a common screen pitch and a common screen angle, and each of said at least two sets of prescribed font data is indicative of halftone dot elements of a linear shape extending in a prescribed extensional direction different form extensional directions represented by the rest of said at least two sets of prescribed font data, and (b) means for recording at least two halftone images corresponding to said at least two sets of image data as a function of font data supplied from said means (a).
Claim 24
Dependent Claim
97 words
An apparatus in accordance with claim 18, wherein said at least two sets of prescribed font data include first to thied font data, halftone dot centers represented by each of first to third font data form a lattice in the shape of a parallelogram, two extensional directions of halftone dot elements represented by said respective first and second font data agree with directions of two adjacent sides of said parallelogram, respectively, and an extensional direction of halftone dot elements represented by said third font data agrees with a direction of one of two diagonals of said parallelogram.
Claim 25
Dependent Claim
64 words
An apparatus in accordance with claim 19, wherein each of said first to thied font data is indicative of said halftone dot elements to have isolated shapes at the halftone-dot area rate of at most about 25 percent, and blank areas to have isolated shapes where said halftone dot elements do not exist at the halftone-dot area rate of at least about 75 percent.
Claim 26
Independent Claim
263 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least three sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least first to third font data indicative of a prescribed shape of a halftone dot depending on a level of given image data at each pixel for said at least three sets of image data, respectively, where each of said at least first to third font data is indicative of halftone dot elements which have a linear shape extending in a prescribed extensional direction different from extensional directions represented by by the rest of said at least first to third font data, and which connect with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate, thereby forming parallel lines with a regular interval, said prescribed extensional direction represented by said third font data agrees with a direction fo a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines represented by said first and second font data, and a pitch of said parallel lines represented by said third font data measured in a direction of a shorter diagonal out of said two diagonals of said minimum parallelogram is equal to a length of said shorter diagonal, and (b) means for recording at least three halftone images corresponding to said at least three sets of image data as a function of font data supplied from said means (a).
Claim 27
Independent Claim
263 words
An apparatus for recording halftone images to be employed in reproducing a color image as a function of at least three sets of image data representing color separation images of said color image, said apparatus comprising: (a) means for storing and outputting at least first to third font data indicative of a prescribed shape of a halftone dot depending on a level of given image data at each pixel for said at least three sets of image data, respectively, where each of said at least first to third font data is indicative of halftone dot elements which have a linear shape extending in a prescribed extensional direction different from extensional directions represented by by the rest of said at least first to third font data, and which connect with each other in said prescribed extensional direction at a prescribed range of halftone-dot area rate, thereby forming parallel lines with a regular interval, said prescribed extensional direction represented by said third font data agrees with a direction fo a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines represented by said first and second font data, and a pitch of said parallel lines represented by said third font data measured in a direction of a shorter diagonal out of said two diagonals of said minimum parallelogram is equal to a length of said shorter diagonal, and (b) means for recording at least three halftone images corresponding to said at least three sets of image data as a function of font data supplied from said means (a).
Claim 28
Dependent Claim
64 words
An apparatus in accordance with claim 21, wherein each of said first to thied font data is indecative of said halftone dot elements to have isolated shapes at the halftone-dot area rate of at most about 25 percent, and blank areas to have isolated shapes where said halftone dot elements do not exist at the halftone-dot area rate of at least about 75 percent.
Claim 29
Dependent Claim
29 words
An apparatus in accordance with claim 22, wherein differences between intervals of said parallel lines represented by said first to third font data are at most about 20 percent.
Claim 30
Dependent Claim
96 words
Halftone images to be employed in reproducing a color image, comprising: (a) a first halftone image of a first color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction, and (b) a second halftone image of a second color having said prescribed screen angle and said prescribed screen pitch, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction.
Claim 31
Dependent Claim
96 words
Halftone images to be employed in reproducing a color image, comprising: (a) a first halftone image of a first color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction, and (b) a second halftone image of a second color having said prescribed screen angle and said prescribed screen pitch, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction.
Claim 32
Dependent Claim
69 words
Halftone images in accordance with claim 24, wherein said halftone dot elements have isolated shapes in each of said first and second halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first and second halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 33
Dependent Claim
114 words
Halftone images in accordance with claim 24, wherein said halftone images further comprises a third halftone image of a third color having said prescribed screen angle and said prescribed screen pitch, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directions, halftone dot centers of each of said first to third halftone images form a lattice in the shape of a parallelogram, said first and second extensional directions agree with directions of two adjacent sides of said parallelogram, respectively, and said third extensional direction agrees with a direction of one of two diagonals of said parallelogram.
Claim 34
Dependent Claim
59 words
Halftone images in accordance with claim 26, wherein said halftone dot centers of each of said first to third halftone images are placed, on an image plane of a reproduced image to be produced with said first to third halftone images, at same positions as said halftone dot centers of the rest of said first to third halftone images.
Claim 35
Dependent Claim
64 words
Halftone images in accordance with claim 26, wherein said halftone dot centers of each of said first to third halftone images are placed, on an image plane of a reproduced image to be produced with said first to third halftone images, at different positions from positions at which said halftone dot centers of the rest of said first to third halftone images are placed.
Claim 36
Dependent Claim
69 words
Halftone images in accordance with claim 26, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 37
Dependent Claim
28 words
Halftone images in accordance with claim 29, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
Claim 38
Dependent Claim
213 words
Halftone images to be employed in reproducing a color image, comprising: (a) a first halftone image of a first color, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction to thereby form parallel lines with a first interval, (b) a second halftone image of a second color, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction to thereby form parallel lines with a second interval, and (c) a third halftone image of a third color, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directoins to thereby form parallel lines with a third interval, said third extensional direction agreeing with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, a pitch of said parallel lines in said third halftone image which is measured in a direction of a shorter diagonal out of said two diagonals of said minium parallelogram being equal to a length of said shorter diagonal.
Claim 39
Dependent Claim
213 words
Halftone images to be employed in reproducing a color image, comprising: (a) a first halftone image of a first color, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction to thereby form parallel lines with a first interval, (b) a second halftone image of a second color, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction to thereby form parallel lines with a second interval, and (c) a third halftone image of a third color, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directoins to thereby form parallel lines with a third interval, said third extensional direction agreeing with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, a pitch of said parallel lines in said third halftone image which is measured in a direction of a shorter diagonal out of said two diagonals of said minium parallelogram being equal to a length of said shorter diagonal.
Claim 40
Dependent Claim
69 words
Halftone images in accordnce with claim 31, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elemnets do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 41
Dependent Claim
21 words
Halftone images in accordance with claim 32, wherein differences between said first to third intervals are at most about 20 percent.
Claim 42
Dependent Claim
28 words
Halftone images in accordance with claim 33, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
Claim 43
Dependent Claim
98 words
A printed color image reproduced by overprinting at least two halftone images, comprising: (a) a first halftone image of a first color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction, and (b) a second halftone image of a second color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction.
Claim 44
Dependent Claim
98 words
A printed color image reproduced by overprinting at least two halftone images, comprising: (a) a first halftone image of a first color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction, and (b) a second halftone image of a second color having a prescribed screen angle and a prescribed screen pitch, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction.
Claim 45
Dependent Claim
65 words
A printed color image in accordance with claim 35, wherein said halftone dot elements have isolated shapes in each of said first and second halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first and second halftone images at least about 75 percent.
Claim 46
Dependent Claim
119 words
A printed color image in accordance with claim 35, wherein said at least two halftone images further comprise a third halftone image of a third color having said prescribed screen angle and said prescribed screen pitch, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directions, halftone dot centers of each of said first to third halftone images form a lattice in the shape of a parallelogram, said first and second extensional directions agree with directions of two adjacent sides of said parallelogram, respectively, and said third extensional direction agrees with a direction of one of two diagonals of said parallelogram.
Claim 47
Dependent Claim
43 words
A printed color image in accordance with claim 37, wherein said halftone dot centers of each of said first to third halftone images are placed at same positions as said halftone dot centers of the rest of said first to third halftone images.
Claim 48
Dependent Claim
48 words
A printed color image in accordance with claim 37, wherein said halftone dot centers of each of said first to third halftone images are placed at different positions from positions at which said halftone dot centers of the rest of said first to third halftone images are placed.
Claim 49
Dependent Claim
71 words
A printed color image in accordance with claim 37, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 50
Dependent Claim
30 words
A printed color image in accordance with claim 40, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
Claim 51
Dependent Claim
215 words
A printed color image reproduced by overprinting at least three halftone images, comprising: (a) a first halftone image of a first color, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction to thereby form parallel lines with a first interval, (b) a second halftone image of a second color, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction to thereby form parallel lines with a second interval, and (c) a third halftone image of a third color, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directoins to thereby form parallel lines with a third interval, said third extensional direction agreeing with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, a pitch of said parallel lines in said third halftone image which is measured in a direction of a shorter diagonal out of said two diagonals of said minium parallelogram being equal to a length of said shorter diagonal.
Claim 52
Dependent Claim
215 words
A printed color image reproduced by overprinting at least three halftone images, comprising: (a) a first halftone image of a first color, halftone dot elements in said first halftone image being formed in a linear shape extending in a first extensional direction to thereby form parallel lines with a first interval, (b) a second halftone image of a second color, halftone dot elements in said second halftone image being formed in a linear shape extending in a second extensional direction different from said first extensional direction to thereby form parallel lines with a second interval, and (c) a third halftone image of a third color, halftone dot elements in said third halftone image being formed in a linear shape extending in a third extensional direction different from said first and second extensional directoins to thereby form parallel lines with a third interval, said third extensional direction agreeing with a direction of a longer diagonal out of two diagonals of a minimum parallelogram which is formed of said parallel lines in said first and second halftone images, a pitch of said parallel lines in said third halftone image which is measured in a direction of a shorter diagonal out of said two diagonals of said minium parallelogram being equal to a length of said shorter diagonal.
Claim 53
Dependent Claim
72 words
A printed color image in accordance with claim 42, wherein said halftone dot elements have isolated shapes in each of said first to third halftone images at the halftone- dot area rate of at most about 25 percent, and blank areas where said halftone dot elements do not exist have isolated shapes in each of said first to third halftone images at the halftone-dot area rate of at least about 75 percent.
Claim 54
Dependent Claim
22 words
A printed-color image in accordance with claim 43, wherein differences between said first to third intervals are at most about 20 percent.
Claim 55
Dependent Claim
30 words
A printed color image in accordance with claim 44, wherein said first to third halftone images are halftone images for magenta ink, cyan ink and black ink in arbitrary order.
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