US6231652B1
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Aqueous ink compositions and ink-jet printing method using the same
Assignee: Ricoh Co Ltd
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Filing: 1999-08-04
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Granted: 2001-05-15
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Expires: 2019-08-04
Abstract
Abstract An aqueous ink composition contains a colorant and a humectant, and has a surface tension γ of less than 50 mN/m when measured by a maximum bubble pressure method at 25° C., with a bubble frequency ν of the aqueous ink composition being set at less than 1 Hz, and a surface tension γ of more than 40 mN/m when measured by the maximum bubble pressure method at 25° C., with the bubble frequency ν of the aqueous ink composition being set at more than 5 Hz. In addition, an ink-jet printing method for forming ink images on an image-receiving medium has the step of ejecting the above-mentioned aqueous ink composition in the form of droplets according to the recording signals at a recording frequency of 8 kHz or more.
Inventors
- 👤 Masayuki Koyano
- 👤 Ikuko Yamada
- 👤 Akio Kojima
- 👤 Kiyofumi Nagai
- 👤 Masato Igarashi
- 👤 Akiko Konishi
- 👤 Hiroyuki Mochizuki
- 👤 Takanori Tsuyuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:01
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/30; C09D11/38
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
87 words
An aqueous ink composition comprising a colorant and a humectant, and having a surface tension γ of less than 50 mN/m when measured by a maximum bubble pressure method at 25° C., with a bubble frequency ν of said aqueous ink composition being set at less than 1 Hz, and a surface tension γ of more than 40 mN/m when measured by said maximum bubble pressure method at 25° C., with said bubble frequency ν of said aqueous ink composition being set at more than 5 Hz.
Claim 2
Dependent Claim
87 words
An aqueous ink composition comprising a colorant and a humectant, and having a surface tension γ of less than 50 mN/m when measured by a maximum bubble pressure method at 25° C., with a bubble frequency ν of said aqueous ink composition being set at less than 1 Hz, and a surface tension γ of more than 40 mN/m when measured by said maximum bubble pressure method at 25° C., with said bubble frequency ν of said aqueous ink composition being set at more than 5 Hz.
Claim 3
Dependent Claim
50 words
The aqueous ink composition as claimed in claim 1 , wherein said bubble frequency ν and said surface tension γ measured by said maximum bubble pressure method at 25° C. are in the relationship of: γ<46 mN/m when ν<1 Hz, 2.5ν+30.5≦γ≦2.5ν+43.5 when 1≦ν≦5 Hz, and γ>43 mN/m when ν>5 Hz.
Claim 4
Dependent Claim
32 words
The aqueous ink composition as claimed in claim 1 , wherein said humectant comprises at least one compound selected from the group consisting of a nitrogen-containing heterocyclic compound and a polyhydric alcohol.
Claim 5
Dependent Claim
29 words
The aqueous ink composition as claimed in claim 3 , wherein said humectant comprises at least one compound selected from the group consisting of 2-pyrrolidone, diethylene glycol and glycerin.
Claim 6
Dependent Claim
32 words
The aqueous ink composition as claimed in claim 4 , wherein said humectant is in an amount of 1 to 20 wt. % of the total weight of said aqueous ink composition.
Claim 7
Dependent Claim
330 words
The aqueous ink composition as claimed in claim 1 , wherein said colorant comprises at least one compound selected from the group consisting of compounds of formulae (III), (IV) and (V): wherein W is —OH group and X is —NH 2 group, or W is —NH 2 group and X is —OH group, and Q 1 is a hydrogen atom or —SO 3 M group, in which M is a cation selected from the group consisting of alkali metal ion, quaternary ammonium cation, quaternary phosphonium cation and alkanol amine cation; wherein Q 2 is a hydrogen atom or —COOM group, Q 3 is a hydrogen atom, —COOM group or —SO 3 M group, and Q 4 is a hydrogen atom, —CH 2 COOM group or —CH 2 CH 2 COOM group, in which M is a cation selected from the group consisting of alkali metal ion, quaternary ammonium cation, quaternary phosphonium cation and alkanol amine cation; and wherein W is —OH group and X is —NH 2 group, or W is —NH 2 group and X is —OH group, Y and Z are each independently —OH group or —NR 3 R 4 group, Q 5 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, —COOM group, —SO 3 M group or —NR 3 R 4 group, and Q 6 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, —COOM group or —SO 3 M group, in which M is a cation selected from the group consisting of alkali metal ion, quaternary ammonium cation, quaternary phosphonium cation and alkanol amine cation; and R 3 and R 4 are each independently a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, or R 3 and R 4 may form a substituted or unsubstituted five-membered or six-membered ring in combination with the nitrogen atom.
Claim 8
Dependent Claim
32 words
The aqueous ink composition as claimed in claim 6 , wherein said colorant is in an amount of 1 to 10 wt. % of the total weight of said aqueous ink composition.
Claim 9
Dependent Claim
126 words
An ink-jet printing method for forming ink images on an image-receiving medium, comprising the step of ejecting an aqueous ink composition in the form of droplets according to recording signals at a recording frequency of 8 kHz or more; said aqueous ink composition comprising a colorant and a humectant, and having a surface tension γ of less than 50 mN/m when measured by a maximum bubble pressure method at 25° C., with a bubble frequency ν of said aqueous ink composition being set at less than 1 Hz, and a surface tension γ of more than 40 mN/m when measured by said maximum bubble pressure method at 25° C., with said bubble frequency ν of said aqueous ink composition being set at more than 5 Hz.
Claim 10
Dependent Claim
126 words
An ink-jet printing method for forming ink images on an image-receiving medium, comprising the step of ejecting an aqueous ink composition in the form of droplets according to recording signals at a recording frequency of 8 kHz or more; said aqueous ink composition comprising a colorant and a humectant, and having a surface tension γ of less than 50 mN/m when measured by a maximum bubble pressure method at 25° C., with a bubble frequency ν of said aqueous ink composition being set at less than 1 Hz, and a surface tension γ of more than 40 mN/m when measured by said maximum bubble pressure method at 25° C., with said bubble frequency ν of said aqueous ink composition being set at more than 5 Hz.
Claim 11
Dependent Claim
41 words
The ink-jet printing method as claimed in claim 8 , wherein said aqueous ink composition is deposited on said image-receiving medium with a deposition amount of 2.5 to 25 g/m 2 when said image-receiving medium is a sheet of plain paper.
Claim 12
Dependent Claim
65 words
The ink-jet printing method as claimed in claim 8 , wherein said aqueous ink composition is ejected from a nozzle and said aqueous ink composition has a contact angle of at least 40° with respect to plain paper and a contact angle of no more than 50° with respect to a material comprising an ink flow path of an ink-jet printer provided with said nozzle.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
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