Patent EP0738068A2 successfully refreshed from Google Patents.
EP0738068A2
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Random printing techniques for liquid ink printers
Assignee: Xerox Corp
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Filing: 1996-04-03
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Granted: —
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Expires: 2016-04-03
Abstract
Abstract Random printing techniques for liquid ink printers include forming masks in a random mask buffer (70) having randomly generated ON values which are ANDed by an AND circuit (74) with the information to be printed in a swath buffer (64). The randomness of the masks improves printing quality and reduces printhead signature problems resulting from printhead defects including misdirected or inoperative nozzles or jets. Masks wherein the ON values are generated with a 50% probability require two masks to print each and pixel location. Masks having the ON values generated with a 25% probability require four masks. Partial advance of the recording medium for overlapping adjacent swaths of scanning carriage type printer is possible to further improve printing by reducing printhead signature defects and "banding".
Inventors
- 👤 Peter A. Torpey
- 👤 Vaughan L. Dewar
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:52
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/19; H04N1/191; H04N1/1911; G; G06; G06K; G06K15/00; G06K15/02; G06K15/10; G06K15/102; G06K15/105; G06K15/107; G06K2215/00; G06K2215/111
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
A method of printing an image on a recording medium (19) with a liquid ink printing apparatus (10) ejecting ink on the recording medium to form images comprising dots (78) of ink, the method comprising the steps of: selecting a first plurality of dots (80) to be deposited on the recording medium according to a random selection process applied to bits of the image; depositing the first plurality of dots (80) on the recording medium during a first printed swath (76); and depositing a second plurality of dots, not selected to be deposited in said first selecting step, on the recording medium during a second printed swath (82).
Claim 2
Dependent Claim
68 words
The method of printing of claim 1, wherein said selecting step comprises generating a mask including a plurality of randomly selected ON values wherein the randomly selected ON values correspond to the first plurality of dots; and wherein the randomly selected ON values of the mask are ANDed by an AND circuit (74) with the image in a swath buffer (64) to select the first plurality of dots.
Claim 3
Dependent Claim
32 words
The method of printing of claim 2, wherein said generating step comprises generating a mask including a plurality of randomly selected ON values having about a fifty percent probability of being ON.
Claim 4
Dependent Claim
32 words
The method of printing of claim 2, wherein said generating step comprises generating a mask including a plurality of randomly selected ON values having about a twenty-five percent probability of being ON.
Claim 5
Dependent Claim
37 words
The method of printing of claim 2, further comprising printing a portion of the image having a width substantially equivalent to the length of a linear array of nozzles in a printbar (32,40) of the printing apparatus.
Claim 6
Dependent Claim
81 words
The method of printing of claim 5, wherein said generating step further comprises generating a mask including a plurality of columns corresponding to the number of nozzles in the linear array of nozzles; or wherein said generating step includes generating a single mask set (110) for printing the entire image; or wherein said generating step includes generating a plurality of mask sets (102,104,106,108), wherein each of the plurality of mask sets corresponds to a printing swath of the liquid ink printbar.
Claim 7
Independent Claim
102 words
A method of printing with a liquid ink printbar (32,40) ejecting ink on a recording medium (19) to form an image printed in multiple swaths (76,82) including dots, comprising the steps of: selecting a number of swaths for printing the image; randomly selecting a first plurality of dots (80) to be deposited on the recording medium according to a probability of selection as a function of the number of swaths; depositing the first plurality of dots (80) on the recording medium; and depositing a second plurality of dots, not selected to be deposited in said first selecting step, on the recording medium.
Claim 8
Dependent Claim
40 words
The method of claim 7, wherein said randomly selecting step comprises randomly selecting a first plurality of dots to be deposited on the recording medium according to a probability of selection equal to the reciprocal of the number of swaths.
Claim 9
Independent Claim
65 words
The method of claims 7 or 8, further comprising generating a mask including a plurality of randomly selected ON values wherein the randomly selected ON values correspond to the first plurality of dots; and wherein the randomly selected ON values of the mask are ANDed by an AND circuit (74) with the image in a swath buffer (64) to select the first plurality of dots.
Claim 10
Dependent Claim
36 words
The method of claim 9, wherein said generating step comprises generating a mask including a plurality of randomly selected ON values having about a fifty percent probability or about a twenty-five percent probability of being ON.
References Cited (Backward Citations)
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