WO2000015724A1

WO2000015724A1 - Method of ink-jet recording

Info

Publication number: WO2000015724A1
Application number: PCT/JP1999/000803
Authority: WO
Inventors: Taisaburo Sakai; Maria Sakai; Reiko Sakai; Miwako Sakai; Akiko Sakai
Original assignee: Taisaburo Sakai; Maria Sakai; Reiko Sakai; Miwako Sakai; Akiko Sakai
Priority date: 1998-09-16
Filing date: 1999-02-22
Publication date: 2000-03-23
Also published as: JP2000086958A

Abstract

A method which comprises performing ink-jet recording with a water-base ink obtained by dissolving in water an alkali metal salt of a leucosulfuric ester which is a quinone-type insoluble organic dye, and then giving light energy to the ink dots formed on the receiving material to change the dye into an insoluble dye. Thus, the durability (resistances to light, water, and heat) of the applied ink can be improved to the same level as that for printing inks applied with plates.

Description

Description Inkjet recording method Technical field

The present invention relates to an inkjet recording method. More specifically, the present invention relates to an ink jet recording method for fixing ink by insolubilizing a photosensitive water-soluble coloring material contained in an ink by applying light energy to an ink dot on the recording material on which the ink jet recording has been performed. Background art

In the ink jet recording method, printing or recording of an image is performed by ejecting minute droplets of ink from a nozzle and attaching the droplets to a surface of a recording material such as paper. Various ink jet recording methods have been proposed, and a method called a continuous method is disclosed in, for example, U.S. Pat. No. 3,298,030 and U.S. Pat. Nos. 3,596,275. I have. In the drop-on-demand method, US Pat. Nos. 3,964,398 discloses a method in which the deformation of a piezo element is applied to the driving force of ink ejection. An ink jet recording method for discharging ink droplets using thermal energy is disclosed in U.S. Pat. Nos. 4,251,82. Although each of these patent publications proposes a method of discharging ink droplets, it does not describe an ink composition suitable for ink jet recording. However, in any of the ink jet recording methods, the ink is ejected from the orifice of the fine nozzle as a fine droplet at a high speed, so that the ejection stability of the ink droplet is greatly affected by the viscosity and surface tension of the ink. . That is, the ink viscosity is It is desirable that the surface tension of the ink be as small as possible and the surface tension of the ink be as large as possible. If the ink viscosity is large, it becomes difficult to supply ink stably to the recording head following high frequency driving in the ink chamber. In addition, when the surface tension of the ink is low, it is difficult to fly the ink droplet in an accurate direction because the ink droplet wets the nozzle opening more, and it is preferable that the position of the ink droplet landing point is shifted. Cause no situation.

For the above reasons, aqueous inks containing water as a main solvent are generally used as ink jet recording inks. Water-soluble dyes such as acid dyes, direct dyes and basic dyes are used as coloring materials.

However, there is a problem that the printed matter recorded with the aqueous ink containing such a water-soluble dye has a low water resistance of the coloring material. In addition, since the light resistance was weak, the preservability of the printed matter was insufficient, and the printed matter was not practical.

To address this problem, many proposals have been made to use aqueous inks in which pigments are dispersed. For example, Japanese Unexamined Patent Publication No. Sho 56-147859 describes an aqueous ink containing an organic pigment as a coloring material. However, an aqueous ink in which an organic pigment, which is solid fine particles, is dispersed in water is a heterogeneous ink composed of a solid phase and a liquid phase, and although a dispersing agent (surfactant) is added, it is essentially insoluble. It is stable. According to this method, the robustness of the printed matter can be satisfied to some extent, but it is difficult to maintain a stable ink ejection ability when used as an ink for ink jet. If the ink jet recording is continued, the ink discharge becomes gradually unstable, and eventually the ink discharge becomes impossible. That is, the problem of nozzle clogging occurs. To solve this problem, use a water-based ink containing a water-soluble coloring material to prepare an ink jet, and then insolubilize the color on paper (recorded). It is rational to settle the ink.

Sulfuric acid sodium salts of vat dye leuco compounds have photosensitivity, and it is conventionally known that they are photochemically oxidized by light irradiation to regenerate the original insoluble dye. For example, UK Patent No. 354,575 and UK Patent No. 4,31,072 propose a method for obtaining a wet color photograph utilizing this property.

Leuco compound sulfate sodium salt absorbs ultraviolet and visible light having a wavelength of 200 to 600 nm. When light energy is applied to the aqueous solution, for example, when ultraviolet light is irradiated, the molecules are excited and the insoluble dye is regenerated through the following process. 4,4'-Dimethyl-6.6 'dichlorothioin digo leuco compound sulfate sodium salt is shown as an example:

0 4

Compounds (almost ^ color)

) Insoluble dye (clear red) Vat dyes do not dissolve in water, but become water-soluble when an alkaline reducing agent is added. For example, it is reduced by caustic soda and hydrosulfite to water-soluble leuco compounds. A quinone-type organic pigment having two or more carbonyl groups in a conjugated double bond system in the molecule also becomes a water-soluble leuco compound. The molecular absorption spectrum of the oral compound is on the short wavelength side as compared with the original insoluble dye, and has absorption in the ultraviolet wavelength region. Therefore, leuco compounds are photosensitive and oxidize upon exposure to regenerate the original insoluble dye. a Since the compound is easily oxidized, it is unstable in the air and is inconvenient to handle. Therefore, the stabilization of leuco compounds by esterification with sulfuric acid is disclosed, for example, in British Patent No. 1,86,057. This was called a soluble vat dye and was used for dyeing fibers. In dyeing, soluble vat dyes are hydrolyzed with acid and thermal energy to form the original insoluble dye. Soluble vat dyes contain only about 30% of soluble dyes, that is, leuco compound sulfates.Others are formulated with auxiliary agents, etc. There is a disadvantage that is slow. Therefore, it is not suitable for ink jet recording ink. Further, there was no color tone suitable for use as a coloring material for ink jet recording ink. In order to record an image in three primary colors, the peak (maximum absorption, A inax) in the absorption spectrum curve of the colorant has a yellow colorant and a peak (maximum) near 430 nm. A magenta colorant whose absorption (inax) is around 530 ntn and a cyan colorant whose peak (maximum absorption, λmax) is around 640 nm are required.

In the present invention, a photosensitive water-soluble coloring material having the three primary colors of yellow, magenta and cyan is synthesized, and an ink jet 3'd recording is performed using an aqueous ink containing the same. Gives light energy to the ink dots on his lid 鉍 The purpose is to insolubilize the coloring material to fix the ink at the same speed as the printing speed of ink jet recording. Disclosure of the invention

After ink jet recording using an aqueous ink containing a photosensitive water-soluble coloring material synthesized by the following method, the ink dots on the recording material are combined using the light energy application method and air oxidation method described below. It is now possible to insolubilize color materials at high speed and fix the ink. The photosensitive water-soluble coloring materials required for the three primary colors were made by the method described below. The method for synthesizing the sulfate salt of the leuco compound is as follows. Chlorosulfonic acid is added to dry pyridine 500 parts under cooling at a temperature of 15 to 20 ° C at a temperature of 15 to 20 ° C while adding 100 parts of chlorosulfonic acid little by little so that the liquid temperature does not exceed 20 ° C. Make noviridine adduct. When 100 parts of the dried pure vat dye is added thereto, and 40 parts of pure iron powder is added all at once while stirring, the reaction mixture reaches 50 to 60 ° C. without heating. The esterification reaction is completed in about 6 hours while stirring is continued. Thereafter, the reaction after the mixture about 6 times the amount of 5% sodium hydroxide pyridine under reduced pressure by adding _c antifoam stirring was poured into ice water containing recovered by vacuum distillation, about the total amount by adding water 3 Heat the mixture to 800 ° C, and filter after 2 hours. After the filtrate is concentrated by distillation under reduced pressure, an ester sulfate of a leuco compound is obtained by the salt Xin method. Dimethylaniline may be used in place of the above-mentioned pyridine, and feed may be used in place of the above-mentioned iron powder.

By the above method, photosensitive water-soluble coloring materials of yellow, magenta, and cyan were obtained. These coloring materials are listed in Examples to 3. The black ink was produced by the method described in Example 4. All of the photosensitive water-soluble coloring materials listed below can be prepared from the precursor insoluble dye by the above-mentioned method. Used as a starting material Exposure (insolubilized) Insoluble dye used in the present invention Hue after photosensitive water-soluble coloring material

Strength index number (chemical structural formula)

C I.7 0 6 0 0 (reddish yellow) C.I.pat yellow

0 «S0 ₃ Na

C 丄 6 7 3 0 0 (greenish yellow)

C. Bat Yellow 2

(货)

CI5 9 10 0 0 (reddish yellow) 1.Bat yellow 4 CI6 0 5 3 0 Light taste

CI

(蛘 light yellow)

S0 ₃ Na

C. I.5 9 1 0 5 (clear

C.I.Bat Orange 1 Reddish yellow)

C. I.5 9 7 0 5 (Blank orange 2 reddish yellow)

C.1.5 9 3 0 0 (clear reddish

C. orange 3 orange)

C1.5 9 7 1 0 (reddish

C.I.Bat Orange 4

Green)

C.I.7 3 3 3 5 Vivid reddish

C. Orange Orange 5

Orange)

(Yellow orange)

(Yellow

Orange)

(Clear red)

(Clear

Magenta)

CI.733 5 5

(Blued red) hot red 6

0CH ' C I.6 7 0 0 0

I. Bread red 1 o

(Blue tint)

(Clear I magenta)

(Clear yellowish red)

C I.7390 5

C.I.Pigment Red 2 0 9

(Clear magenta)

C I.6 0 0 1 0

Shibat Violet i

(Clear purple)

(Clear magenta)

C. I.7339 5 (clear

C.I.Bat Biorelett 3

Reddish purple)

C I.734 0 0 a (purple)

C.1. Bat Violet 4

(Reddish purple)

(purple)

C I.7 3 6 0 0

(Clear purple)

C. Butt Violet 8

CI7 3 0 0 0 Na0 ₃ S-0

(Reddish blue)

C. Back Blue 1

(綠 taste blue)

_{C I.73 0 5 5 Na0 3 S0} 0-S0 3 Na

(Reddish blue) shibat blue 3 C. .Br

C-C

NI ^ NH

(Clear reddish blue)

C I.73 0 6 5

C.1.Bat Blue 5 Dr Blue)

C I.69 82 5

I (clear blue) Knott blue 6

S0 ₃ Na )

Blue)

Color

(Clear cyan)

)

(Dark green)

(鲜 light blue green)

Color)

(Reddish brown)

(Tea

(Reddish brown)

(咭 reddish brown)

(Saiami U color)

(Blueish black)

C. I.73 6 6 0

C.1 Knot black 3 5 (blueish blue)

(Blueish black)

(Blueish black)

(Blueish black)

(Leave color)

CI. 7 1 0 5 0

C.I.Bat Green 8

Khaki)

C I. 6 9 5 2 5

C.I.Bat Black 2 5

N

Leave color)

After ink jet recording is performed using the aqueous ink containing the photosensitive water-soluble coloring material, ink fixing is performed by applying light energy to the ink dots on paper (recording material) to insolubilize the coloring material. . As a means for applying light energy, there are a method of irradiating with a UV lamp and a method of irradiating with a laser. The laser can instantly fix the ink by the focused high-energy light beam, and can prevent the ink dot from bleeding.

This section describes how to use an easily available UV lamp ₍ Conventionally, a mercury discharge lamp has been used as a UV lamp. Mercury discharge lamps are also simply called mercury lamps or mercury lamps. The light emitted from the mercury lamp has a different emission spectrum according to the mercury vapor pressure in the discharge tube. A low-pressure mercury lamp (mercury vapor pressure P = 0.01 mm Hg) is a discontinuous spectrum that mainly emits ultraviolet light with a wavelength of 254 mm. Low-pressure mercury lamps have low mercury vapor pressure and can only produce low-output lamps, but they emit ultraviolet light with a wavelength of 254 nm efficiently. Low-pressure mercury lamps are used as germicidal lamps.

On the other hand, in a high-pressure mercury lamp (mercury vapor pressure P = 760 mmHg), the spectrum shifts to the longer wavelength side, and wavelengths such as 365 mm, 405 mm, and 436 mm are obtained. Is emitted, and the emission spectrum is also a discontinuous spectrum. Recently, it has been revealed that an ultraviolet fluorescent lamp is suitable as an exposure UV lamp used in the present invention. Ultraviolet fluorescent lamps have a continuous spectrum mainly in the wavelength range of 300 to 400 nm, although there are some differences depending on the composition of the fluorescent substance coated on the inner wall of the discharge tube (quartz glass tube). It has been clarified that the coloring material in the ink dot can be insolubilized with relatively low power consumption because the coloring material efficiently absorbs light energy.

The structure of the discharge tube of an ultraviolet fluorescent lamp is the same as that of a low-pressure mercury lamp. Low-pressure mercury lamps are also called germicidal lamps. Table 1 below shows the emission spectra of low-pressure mercury lamps and high-pressure mercury lamps. These are discontinuous spectra. Table 2 shows an example of the continuous emission spectrum of an ultraviolet fluorescent lamp compared with the spectrum of a low-pressure mercury lamp.

It was also clarified that the combined use of ultraviolet fluorescent lamps and germicidal lamps, that is, the use of hybrid lamps, can further accelerate the insolubilization of coloring materials.

In this way, a relatively low-power UV lamp is used to insolubilize the photosensitive water-soluble coloring material at the same printing speed as the printing speed of ink jet recording, thereby shortening the time. 00/15724

twenty one

% ^ I) (

-1

S o

It has become possible to fix the ink between the two.

Discontinuous emission spectrum of low-pressure and high-pressure mercury lamps

^ 100

80

60

40

20

rm

0

Wavelength (nm)

200 300 400 500 600 700 800 900 1000 Wavelength (nm) Table 2: Ratio of continuous emission spectrum of ultraviolet fluorescent lamp to discontinuous spectrum of low pressure mercury lamp.

80

60

40

20

0

200 300 400 500 600 700 800 900 1000 Wavelength (nm) In the ink jet recording method, the diameter of the ink droplet ejected from the nozzle of the recording head is 10 to 50 μm. Since printing or image recording is performed by the ink of the minute droplets, normal printing or image recording cannot be obtained unless the paper (recording material) is securely fixed. In the ink jet recording method of the present invention, the back surface of the paper is suctioned and fixed by vacuum (vacuum). In conventional precision printing presses, there is a method to fix the paper by vacuum (vacuum) to prevent color misregistration.

The ink jet recording method of the present invention does not require coated paper (coated paper) because it aims at printing on plain paper and obtaining the same level of printing durability as plate printing ink. Plain paper with pulp fibers exposed on the surface and fluff has air permeability. It has been clarified that the insolubilization of the photosensitive water-soluble coloring material of the present invention is further accelerated by sucking and fixing the back surface of the paper by vacuum (vacuum). This is considered to be because the air oxidation of the coloring material is promoted by the suction under reduced pressure. A small amount of ozone is generated around the discharge tube by the UV radiation of the UV lamp. This ozone is also thought to promote the oxidation of the coloring material. The distance between the UV lamp and the paper is 1 to 2 cm. Since the UV lamp is covered with a reflective lamp hood, air containing ozone can efficiently pass through the paper by vacuum (decompression) to remove the coloring material. Used for oxidation.

The water fastness and light fastness of the recorded images and prints obtained by the ink jet recording method of the present invention are far superior to those of aqueous inks containing conventional water-soluble dyes (direct dyes, acid dyes, basic dyes). The durability of the printed matter is at the same level as the letterpress printing ink.

The ink jet recording method of the present invention can be applied not only to paper as a recording material, but also to textiles such as cotton, silk, wool, and nylon, leather, and nonwoven fabric. After ink jet recording using the aqueous ink containing the photosensitive water-soluble coloring material described above, the ink on the paper is UV-irradiated with a hybrid lamp using a fluorescent lamp for ultraviolet light and a germicidal lamp to insolubilize the coloring material. FIG. 1 shows a cross section of an apparatus embodying an ink jet recording method for fixing paper by low pressure suction.

In FIG. 1, the ink jet recording head 1 is located directly above the rotating drum 2, and the recording heads for yellow, magenta, cyan, and black inks required for recording a full-color image are arranged in order from the left. They are installed side by side. The rotating drum 2 has an infinite number of pores on the surface of the cylinder and is rotated clockwise by the rotating shaft 3, and its rotation speed is synchronized with the printing speed of the recording head. The inside of the rotary drum 2 is a decompression chamber 4, which is connected to an intake pump 8 through an intake pipe 6 from an intake port 5 inside the rotary shaft 3.

The paper 14 supplied from the paper feed 12 is attracted to the surface of the rotary drum 2 by the suction force of the decompression chamber 4 and fixed on the drum. When the paper rotates below the recording head 1, black ink (Bk) is first recorded on the paper, and the paper is further rotated and exposed by the UV lamp. The UV lamp is a hybrid lamp in which ultraviolet fluorescent lamps 9 and germicidal lamps 10 are alternately arranged. The lamp hoods il a, 11 b and 11 c reflect ultraviolet light for effective use.Also, pass the paper to the decompression chamber 4 inside the drum without escaping the ozone generated around the lamp to the outside. This has the effect of remarkably accelerating the insolubilization of the ink coloring material on the paper.

The rotating drum makes one revolution, and then cyan-ink (C) is recorded. In this way, the drum rotates four times to record magenta (M) and yellow ink (Y) sequentially. After the drum rotates four times, the exhaust pressure valve 7 is opened, and the recording paper 15 adsorbed on the drum surface is discharged from the paper discharge roller 13. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view of an apparatus for an ink jet recording method of the present invention.

Explanation of reference numerals

1 Inkjet recording head

2 rotating drum

3 Rotary axis

4 Decompression chamber

5 Inlet

6 Intake pipe

7 Drain valve

8 Suction pump

9 Ultraviolet fluorescent lamp

10 Disinfection lamp (low pressure mercury lamp)

1 1 1b and 1 1c

1 2 Paper feed slot

1 3 Paper output

1 4 paper

1 5 Recording paper

Y yellow ink

M magenta ink

C cyan ink

BEST MODE FOR CARRYING OUT THE INVENTION

In order to explain the present invention in more detail, the present invention will be described more specifically by way of examples. All parts or percentages in the examples are based on weight. Example 1

Chlorosulfonic acid 1502 was gradually added to pyridine 7502 at 15 to 20 ° C over about 2 hours to prepare a pyridine-chlorosulfonic acid adduct. At a temperature of 20 to 25 ° C, an insoluble dye having the following chemical structural formula (Circular index number C. 1. Vat Yellow 11 / structure number C.I. Was added and stirring was continued for a while.

Thereafter, pure iron powder 100? Was added all at once, and stirring was further continued. The temperature of the reaction mixture increased to 55 ° C., which was heated to 60 ° C., and stirred at this temperature for 3 hours to complete the esterification reaction. This reaction mixture was poured into 5 liters of a 5% aqueous sodium hydroxide solution to neutralize the mixture. The released pyridine was recovered by vacuum distillation at 28 to 30 ° C. The residue was filtered to remove residues such as iron oxide, and the filtrate was concentrated by evaporating under reduced pressure, and then sodium chloride was added for salting out. The resulting dark reddish-brown precipitate was a light-sensitive water-soluble coloring material represented by the following chemical structural formula, and upon irradiation with ultraviolet rays, produced a clear greenish-yellow insoluble pigment. This photosensitive water-soluble coloring material was designated as photosensitive water-soluble yellow coloring material A, and was used for preparing an ink for evaluation test described below:

(Photosensitive water-soluble yellow coloring material A) Example 2

Force index structure number CI7 0 4 0 0, C.1.6 7 3 0 0.CI6 0 5 3 0, C.1.6 0 6 0 5.C.1.6 7 8 1 0, C.1.7 3 3 6 5 , CI 7 3 8 5, 1.7 3 9 0 5, as starting materials, respectively, and the following photosensitive water-soluble yellow coloring materials B, C, D, E, and Water-soluble magenta coloring materials F \ G.H, I were obtained. These colorants were used in preparing the evaluation test inks described below:

(Photosensitive water-soluble yellow colorant B)

(Photosensitive aqueous yellow color 讨 c)

(Photosensitive water-soluble yellow colorant D)

S0 ₃ Na

(Photosensitive water-soluble yellow one color material E)

(Photosensitive water-soluble magenta coloring material F)

(Photosensitive water-soluble magenta coloring material G)

CI

(Photosensitive water-soluble magenta coloring material H)

(Photosensitive water-soluble magenta coloring material I)

Example 3

The following photosensitive water-soluble cyan coloring materials J and K were obtained in the same manner as in the synthesis method of Example 1 by using the color index structure numbers CI6 7910 and 67915 as starting materials, respectively. . However, copper powder was used instead of iron powder. These coloring materials were used for preparing an evaluation test ink described below:

(Photosensitive water-soluble cyan coloring material J)

(Photosensitive water-soluble cyan coloring material K) Example 4

The following four types of photosensitive water-soluble black colors were prepared in the same manner as in the synthesis method described in Example 1 using the following insoluble dye mixtures (S), (M), (N) and (0) as starting materials, respectively. Lumber L, Μ, Ν and 0 made:

20 parts power index structure number C.1.60530 ―

Insoluble dye mixture α) 80 parts power index structure number C.1.73670

30 parts power index structure number C. 67300

40 parts power color index structure number C.1.73600 Insoluble dye mixture (Μ) 30 parts power color index structure number C.1.73000

20 parts power index structure number C. Ι.6Π25

Insoluble dye mixture (Ν) 80 parts power index structure number C.1.73830

20-part power index structure number C.1.59105

Insoluble dye mixture (0) 80 parts of power index structure number C.1.73670 _

The following four kinds of photosensitive water-soluble black coloring materials thus obtained were used for preparing an evaluation test ink described below:

20 copies

Light water soluble to black colorant

80 copies

Three

〇 Na

Four

Light-soluble, black colorant M;

Three

C '0

C

Light-soluble, water-soluble, black coloring material

0-S0 ₃ Na

Department

-. ,

HC NaO S-0

20 copies

Photosensitive water-soluble, black coloring material 0

80 copies

Example 5

Using the 15 types of photosensitive water-soluble coloring materials 8-0 obtained in Examples 1 to 4 above, aqueous inks for ink jet recording were prepared by the following ink formulation:

Each photosensitive water-soluble coloring material 8 ~ 0 wood) 4 9

1,3-Dimethyl-2-imidazolidinone 3θ β

Distilled water approx.

lOOwfi

Thu) Ink containing photosensitive water-soluble coloring material A was designated as ink (A). Similarly, inks containing the photosensitive water-soluble coloring materials B to N were prepared from inks (B) to (0), respectively. However, only in the case of black color, the color material concentration was set to 62/1 0 QMH. Each of the aqueous inks (8) to (0) containing the photosensitive color material prepared as described above was filled in each of the ink bottles, and the ink jet recording apparatus shown in FIG. The area of c was printed solid. Tests for light, water and heat resistance

Light fastness, water fastness and heat resistance were tested using the test pieces of solid printed matter obtained above. As a comparative example, a solid print using a color laser printer and a solid print using a conventional ink jet printer (a used ink is a water-based ink containing a basic dye as a color material) were tested under the same conditions. I compared. After irradiation for 10 hours using a light fastness test fadeometer (light fastness tester for carbon arc discharge lamps), discoloration was evaluated and evaluated. Explanation of symbols in the table: 〇 · · · Almost no fading

X · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

Explanation of symbols in the table: 〇 · · · Color materials do not dissolve

XHeat resistance test in which coloring material has melted.White paper is superimposed on the test piece, and an eye opening at 180 ° C is placed on it.After 30 seconds, the color is transferred to the blank paper. It was visually judged.

Explanation of symbols in the table: 〇 · ♦ · No color transfer

X · · · color transfer

△ ·, · Discolored Test bellflower

Light resistance test Water resistance test Heat resistance test (10 hours) (80 ° C, 2min.) (180 ° C. 30 seconds) Ink (A) 〇〇インク Ink (B) 〇〇〇 Ink (C) 〇〇〇 Ink (D) 〇〇〇 Ink (E) 〇〇 Ink (F) 〇〇インク Ink (G) 〇〇インク Ink (H) 〇〇インク Ink (I) 〇〇インク Ink (J) 〇〇〇 Ink (K) 〇〇インク Ink (L) 〇〇 Ink (M) 〇〇〇 Ink (N) 〇〇インク Ink (0) 〇〇〇

(Comparative example: solid print with color laser printer) Yellow 〇〇 X Magenta 〇〇 X Cyan 〇〇 X Black O 〇 X

(Comparative example: solid print using a conventional inkjet printer) (The ink used is a water-based ink containing a basic dye as a coloring material.) Yellow XX △ Magenta XX Δ Cyan XX Δ Black XX △ Industrial applicability

As described above, the ink durability of the printed matter according to the ink jet recording method of the present invention is at the same level as the letterpress printing ink, and is superior to the toner of the laser printer. Therefore, it is suitable for an inkjet printer that prints official documents and business documents where long-term storage is important. It can also be used for digital printing and electronic publishing.

Claims

The scope of the claims

1. After the main ink solvent, water, is subjected to ink jet recording using an aqueous ink containing one of the photosensitive water-soluble coloring materials having the following chemical structural formula, light energy is applied to the ink on the recording material. An ink jet recording method characterized by insolubilizing the coloring material and printing a yellow dot and recording an image or an image.

CH

(However, M in the formula represents sodium, potassium or lithium)

2. After the main ink solvent, water, is subjected to ink jet recording using an aqueous ink containing one of the photosensitive water-soluble coloring materials having the following chemical structural formula, light energy is applied to the ink on the recording material. An ink jet recording method characterized in that the coloring material is insolubilized by printing magenta dots and recording an image or an image.

1

(However, M in the formula represents sodium, potassium or lithium)

3. Water, which is the main ink solvent, is subjected to ink jet recording using an aqueous ink containing one of the photosensitive water-soluble coloring materials having the following chemical structural formula, and then light energy is applied to the ink on the recording material. An ink jet recording method characterized in that the coloring material is insolubilized by printing a cyan dot and / or recording an image.

(However, M in the formula represents sodium. Potassium or lithium.)

4. After ink jet recording using water-based ink containing any of the photosensitive water-soluble coloring materials having the following chemical structural formula, the main ink solvent is water. Light energy is applied to the ink on the recording material. An ink jet recording method characterized in that the coloring material is insolubilized to print a black dot and record an image or an image.

(Where M in the formula represents sodium, potassium or lithium) 5. Claims 1, 2, and 3 characterized in that the light energy is provided by an ultraviolet fluorescent lamp. Or the ink jet recording method described in paragraph 4.

6. The paper according to claim 1, wherein the paper used as the recording material is fixed to the substrate by a suction force due to a low pressure, and air oxidation of the ink color material on the paper is promoted. The inkjet recording method according to paragraph 2, paragraph 3, or paragraph 4.