Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-02-16
2004-01-13
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031750, C106S031770, C106S031780, C106S031790
Reexamination Certificate
active
06676737
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel ink composition which results in excellent image quality as well as high image fastness and an image forming method, and in more detail to an ink composition which can be employed in an ink jet recording method and an image forming method which is capable to accomplishing ink jet recording.
BACKGROUND OF THE INVENTION
An ink jet recording method makes it possible to record extremely fine images employing a relatively simple apparatus, and has been increasingly developed in various fields. In broad fields, produced have been printers which utilize ink jet recording systems. Further, a wide variety of ink has been developed depending on need.
Water based ink jet recording compositions are commonly employed for ink jet recording. The water based ink jet recording compositions employed for ink jet recording are mainly divided into dye based ink and pigment based ink.
The dye based ink is highly valued on the market due to its vivid color reproduction as well as its excellent storage stability. On the other hand, it does not sufficiently meet requirements for image retention quality (such as light fastness, minimum bleeding, and the like).
The pigment based ink exhibits higher image retention compared to the dye based ink, but it necessitates a dispersion process for its production. The stability of the resultant dispersion is limited. Therefore, when employing ink jet recording, problems occur such as disadvantages for cost reduction, clogging during use over an extended period of time, and the like. Further, the resultant image quality (such as color reproduction, glossiness, bronzing, and the like) is inferior to dyes.
Under such current situation, demanded have been novel colorants which exhibit the excellent properties of dyes (such as image quality and ink storage stability) and the image retention quality of pigments (such as light fastness, minimum bleeding, and the like).
In recent years, developed has been technology in which specified pigments are subjected to chemical modification so that they become soluble in organic solvents. For example, Japanese Patent Publication Open to Public Inspection No. 7-150068 discloses organic solvent-soluble compounds in which nitrogen atom(s) of pigments such as quinacridone, indigo, and the like, are subjected to chemical modification employing a specified oxycarbonyl group, and further discloses that when the resulting modified compound is subjected to thermal treatment, the original pigment is regenerated (latent pigment technology).
Further, Japanese Patent Publication Open to Public Inspection Nos. 11-246809 and 11-293166 disclose technology in which said latent technology is applied to ink jet recording. However, compounds, which are obtained by substituting disclosed pigments, are only soluble in organic solvents. Thus when ink is prepared, water-insoluble organic solvents are required.
Employed as water-insoluble organic solvents, which are employed to prepare said ink, are low-boiling point and high-boiling point water-insoluble organic solvents. Said low-boiling point water-insoluble organic solvents are not preferred because during printing as well as the drying process, organic solvents volatize to result in adverse effects to humans as well as to the environment. Further, the volatilization of said water-insoluble organic solvents on the printing head results in frequent clogging of the orifice of said head. Still further, when said high-boiling point water-insoluble organic solvents are employed, the drying properties of images are degraded and a large amount of solvent remains. Specifically, when special glossy paper sheets, which are capable of producing high quality, are used, drying properties are further degraded. As a result, when the printed paper sheet is placed on another, parts of the image may be transferred to the reverse surface.
It is a first object of the present invention to provide an ink composition which exhibits storage stability of ink for an extended period of time and results in high image quality as well as sufficient image retention. It is a second object of the present invention to provide a method which forms images exhibiting high image quality as well as sufficient image retention, employing a novel water based ink composition.
The aforementioned objects of the present invention are achieved by the embodiments described below.
(1) A water based ink composition characterized in that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is dissolved in a water based solvent.
(2) The water based ink composition described in (1) above, characterized in that that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is the compound represented by General Formula (1) described below:
wherein R
1
represents an alkyl group or an aryl group which may have a substituent, R
2
represents a phenyl group which may have a substituent, and R
3
represents a phenyl group which may have a substituent. However, at least one of R
1
, R
2
, and R
3
is a group represented by General Formulas (2) or (3):
In General Formulas (2) and (3), R
4
represents a substituent having a water solubilizing group, R
5
represents a substituent, and m2 represent 0 to 3. R
6
and R
7
each represent a substituent having a water solubilizing group, R8 represents a substituent, and m
3
represents 0 to 3.
(3) The water based ink composition described in (1) above, characterized in that that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is the compound represented by General Formula (4) described below:
wherein R
9
represents a phenyl group which may have a substituent, R
10
represents a hydroxyl group, or an amino group, an acylamino group or a carbamoyl group which may have a substituent, and m
4
represents 0 to 7. However, at least one substituent of R
9
or R
10
is a group represented by General Formula (2) or General Formula (3), or a group R
9
or R
10
mentioned above which is substituted by the group represented by General Formula (2) or (3).
In General Formulas (2) and (3), each of R
4
, R
6
and R
7
represents a substituent having a water solubilizing group, each of R
5
and R
8
represents a substituent, and m
2
represents 0 to 3.
(4) The water based ink composition described in (1) above, characterized in that that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is the compound represented by General Formula (5) described below:
wherein R
1
l and R
12
each represent a substituent having a water solubilizing group, R
13
and R
14
each represent a substituent, and n
5
and m
5
each represent 0 to 4.
(5) The water based ink composition described in (1) above, characterized in that that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is the compound represented by General Formula (6) described below:
wherein R
15
, R
16
, R
17
, R
18
, and R
19
each represent a hydrogen atom or a substituent having a water solubilizing group. However, at least two of R
15
, R
16
, R
17
, R
18
, or R
19
are substituents having a water solubilizing group.
(6) The water based ink composition described in (1) above, characterized in that that a precursor, which can be converted to an insoluble pigment by at least one means selected from a chemical means, a thermal means, a photodecomposition means, and a radiation means, is the compound represented by General Formula (7) described below:
wherein R
20
and R
21
each
Morimoto Hitoshi
Ohya Hidenobu
Klemanski Helene
Konica Corporation
Muserlian Lucas and Mercanti
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