JP2615567B2 - Inkjet recording method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an ink jet recording method capable of performing high-quality recording on a general-purpose recording medium such as commercially available medium quality paper regardless of the paper quality.

[Conventional technology]

Representative examples of an ink jet recording apparatus having a heating and drying means for a recording liquid include JP-A-55-69465 and JP-A-55-84670.The recording paper is heated by heating the entire platen with a heating element provided inside the platen. This is an effective means for heating the back surface and drying the recording liquid to prevent unnecessary bleeding, paper wrinkles, and stains due to the unfixed recording liquid to realize high-resolution and high-quality image recording.

[Problems to be solved by the invention]

However, commercial and medium-grade paper, which is a typical general-purpose recording paper, is manufactured by using raw pulp, mixed filler,
Since the properties vary widely depending on the configuration and processing method of the wire part and the size press of the paper machine, the ink jet recording characteristics are completely different even on the front and back of the same paper as well as the manufacturer and manufacturing lot. That is, the printing quality greatly depends on the paper quality because the recording liquid absorbency differs. The above prior art relates only to the recording paper heating means and the configuration of the platen portion, and is technically insufficient to realize high quality ink jet recording on various general-purpose recording papers regardless of the paper quality.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide high quality ink jet recording on various general-purpose recording papers regardless of the paper quality.

[Means for solving the problem]

The ink jet recording method of the present invention is a method in which a recording liquid is attached to a general-purpose recording medium such as a commercially available medium quality paper heated to 80 to 140 ° C., and a liquid component having a high vapor pressure in the recording liquid is rapidly vaporized and colored. An ink jet recording method for fixing a residual component containing an agent and a solvent, wherein the residual component has a surface tension at 100 ° C. of 35 mNm ⁻¹ or more.

First, the configuration of an apparatus used in the inkjet recording method of the present invention will be described.

FIG. 1 is a schematic diagram showing a first example of a recording apparatus used in the ink jet recording method of the present invention.

In FIG. 1, the recording head 5 is guided by a carriage guide 6 while being supplied with the recording liquid from a recording liquid tank 15 through a recording liquid supply pipe 16, and moves in the direction of the arrow I. Ink jet recording is performed on the recording paper intermittently feeding a new line in synchronization with the recording head 5 by the recording head 4.

In FIG. 2, the recording head 5 has a plurality of recording liquid ejection ports.
A dot image 13 is formed on the recording paper 3 by recording liquid discharging means such as piezoelectric element control, electric field control, charge control, and thermal ink jet recording. The recording head 5 of this embodiment is a thermal ink jet recording head provided with 24 recording liquid discharge ports in a vertical direction at an interval of 180 dpi, and discharges recording droplets having a diameter of about 90 μm.

The fixed platen 1 is suitably made of a material having good heat diffusion such as an aluminum alloy or a heat conductive plastic material. In this example, an aluminum alloy plate having an average thickness of 1 mm and a size of about 250 mm × 30 mm is used. On the back surface of the fixed platen 1 not facing the recording head 5, a heating element 12 is provided as shown in FIG. Heating element 12
It is appropriate to equally arrange five PTC thermistors for heaters with a rated voltage of 30 V and a normal temperature average resistance value of 22 Ω, or a sheath heater of about 100 V and 250 W is suitable.

The recording paper 3 is slid in contact with the fixed platen 1 heated by the heating element 12, and is preheated and heated to the above-mentioned temperature before and after ink jet recording by contact heat transfer, and the recording liquid on which the ink jet recording is performed adheres to the recording surface. Immediately after that, the ink is dried rapidly to prevent unnecessary dot bleeding, paper wrinkles, and stains due to unfixed recording liquid, thereby obtaining a good printing state. The paper presser 7 prevents the recording paper 3 from sticking, and the recording paper 3
To enhance the heat conduction effect.

When the recording paper 3 is preheated and heated, the recording paper 3 is curled along the shape of the fixed platen 1. In order to remove this curl, the recording paper 3 is printed after ink jet recording.
Is wound around a curl removing roller 14, and is tightened in a direction opposite to the curl direction to remove the curl, and the recording paper 3 can be taken out in a flat state.

FIG. 3 is a schematic diagram showing a second example of a recording apparatus used in the ink jet recording method of the present invention.

The recording head 5 is guided by the carriage guide 6 and moves in the direction of arrow I, and performs ink jet recording on the recording paper 3 which is intermittently fed by the paper feed roller 2 and the guide roller 4 in synchronism with the recording head 5. . on the other hand,
Light emission from the heat source lamp 17 is, for example, a radiation surface, an elliptical surface,
A recording portion on the surface of the recording paper 3 is condensed and irradiated on a heating area 27 before and after recording by a reflector 19 having a curved surface such as a hyperboloid, and is heated by radiant heat transfer. The blower 23
Flows through the air inlet path 24 as shown by arrows II and III, and is sent to a lamp house section composed of the reflection plate 19, the reflection side plates 21a and 21b, and the transparent protective glass 22. And the said lamp house part is air-cooled. After cooling, the air flow passes through the air discharge path 25 as indicated by IV and V and is discharged from the air discharge port 26 toward the recording surface of the recording paper 3, and the convection heat and conduction heat generated by the heat source lamp 17 are transferred to the recording paper surface. Blow heat transfer to

The recording head 5 has a plurality of recording liquid ejection ports as shown in FIG.
A dot image is formed on the recording paper 3 by a recording liquid discharge control means such as piezoelectric element control, electric field control, charge control, and the like, and image recording is performed. In this example, a piezoelectric element is used,
0.141mm pitch, 24 rows of recording liquid outlets in a vertical line, approx.
0.5 μg of recording droplets are ejected.

The heat source lamp 17 is an incandescent lamp represented by a halogen lamp, a xenon lamp, or an infrared lamp. In this example, a 200-W, 250 mm-length bar-shaped halogen lamp is used. The recording width of the recording paper 3 is 220 mm, and a lamp having an effective light emitting portion of at least a longer length is required. The heat source lamp 17 is set at a distance of 60 mm from the paper feed roller 2, and radiates and heats the heating range 27 as described above. The heating state of the recording paper 3 is indicated by a temperature sensor as shown in FIG.
The detected temperature is compared with a set temperature by a comparison circuit built in the light amount control circuit 18, and the light amount is fed back to keep the temperature of the recording paper 3 substantially at the set value. Although the temperature sensor 28 is provided on the front side of the recording paper 3 in FIG. 4, it may be provided on the back side of the recording paper 3. Further, the set temperature can be freely controlled by the user according to the paper quality.

The blower 7 is a blower fan having a flow rate of about 3 m ² / min.
The direction of the flow of the discharge air from the air discharge port 14 is considered so as not to affect the discharge of the recording liquid. The light-shielding cover 20 prevents light radiation from directly hitting the recording head 5 and prevents the recording head from being radiated and heated. In addition, the transparent protective glass 22 prevents dust from adhering to the heat source lamp 17 and the reflecting plate 19.

For the appropriate preheating / heating temperature of the recording paper, if it exceeds 140 ° C, the recording paper will emit smoke or discolor.If it is less than 80 ° C, the recording liquid will evaporate slowly, and it will take a long time before the recording form is fixed on the recording paper. , The printing quality is inferior. Therefore, the preheating / heating temperature of the recording medium and the adhering recording liquid is desirably 80 to 140 ° C.

Next, the recording liquid used in the present invention will be described in detail.
The recording liquid used in the present invention contains a dye and a pigment as colorants, a solvent for preventing drying and solidification in a nozzle, and water as main components.

The present inventors first paid attention to the fixing process of a recording liquid on a recording medium in the ink jet recording apparatus in order to give good print quality to commercially available medium quality paper. FIG. 5 shows a change in the remaining amount of the recording liquid on the recording medium after the ink jet recording. When the recording medium adheres, the recording medium
Because of the heating to ℃, water with a high vapor pressure quickly evaporates rapidly and remains on the recording paper is a solvent and dye for preventing drying, and it is understood that the mechanism is to fix it. .

Furthermore, the present inventor focused on the solvent and dye remaining on the recording paper and proceeded with research.As a result, the surface tension of the mixture at 100 ° C. was 35 mNm ⁻¹ or more. It has been found that high quality ink jet recording can be realized regardless of the paper quality. Further, it has been found that the surface tension of the solvent has a great effect on the printing quality, although any remaining mixture of the solvent and the dye has an effect on the surface tension. Accordingly, the solvent to be mixed with the recording liquid of the present invention is one having a surface tension of 35 mNm ^-1 singly or as a mixture at 100 ° C. Specifically, polyhydric alcohols such as glycerin, diethylene glycol and triethylene glycol, formamide, thiodiglycol, triethanolamine and the like can be mentioned, and these can be used alone or in combination. The addition amount is preferably in the range of 5 to 20% by weight in consideration of the effects on the solubility and quick drying of the dye and pigment.

The colorant to be added to the recording liquid is appropriately selected so as to sufficiently conform to the recording conditions.
Many of conventionally known dyes and pigments are effective. Examples of the dye include various azo dyes, indigoid dyes, phthalocyanine dyes, and the like.Specifically, C.I.
I. Direct Black 19, CI Direct Black 22,
CI Direct Black 154, CI Direct Yellow 1
2, CI Direct Yellow 86, CI Direct Red 1
3, CI Direct Red 17, CI Direct Blue 8
6, CI Direct Blue 90, CI Acid Black 5
2, CI Acid Lereau 17, CI Acid Yellow 2
3, CI Acid Lead 52, CI Acid Lead 254, C.
I. Acid Blue 9 and the like. Examples of the pigment include inorganic pigments and organic pigments, which are dispersed using a dispersant. The particle size of the pigment is preferably in the range of 0.01 to 3 μm. The addition amount is 0.5 to 1 in consideration of clogging, print density, etc.
It can be added in the range of 0 weight percent.

Further, in addition to the components described above, a preservative, a fungicide, a PH regulator, and a chelating agent can be appropriately added to the ink used in the present invention.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

Recording liquids a to j were prepared as examples, and k to o as comparative examples were prepared with the following compositions.

<Recording liquid a> Dye: CI direct black 154 1% Solvent: Diethylene glycol 10% water * Remaining <Recording liquid b> Dye: CI direct black 154 1% Solvent: Glycerin 10% water * Remaining <Recording liquid c> Dye ... CI Direct Black 22 1% Solvent ... Glycerin 10% Methyl Alcohol 10% Water * Remaining <Recording Solution d> Dye ... CI Direct Black 154 1% Solvent ... Thiodiglycol 10% Water * Remaining <Recording Solution e> Dye ... CI Direct Black 154 1% Solvent ... Glycerin 5% Diethylene glycol 3% Thiodiglycol 2% Water * Remaining <Recording solution f> Dye ... CI Direct Black 154 1% Solvent ... Triethylene glycol 10% Water * Remaining <Recording Liquid g> Dye: CI direct black 154 1% Solvent: Glycerin 10% Ethylene glycol 5% Water * Remaining <Recording liquid h> Dye: CI Elect Black 22 1% Solvent: Thiodiglycol 10% Polyethylene glycol # 400 5% Water * Remaining <Recording liquid i> Dye: CI direct black 154 1% Solvent: Diethylene glycol 10% Polyethylene glycol # 300 3% Water * Remaining <Recording liquid j> Dye: CI direct black 154 1% Solvent: Glycerin 10% Triethylene glycol 5% Water * Remaining <Recording liquid k> Dye: CI direct black 154 1% Solvent: Propylene glycol 10% Water * Remaining <Recording liquid 1> Dye: CI direct black 154 1% Solvent: dimethyl sulfoxide 10% water * Remaining <Recording liquid m> Dye: CI direct black 154 1% Solvent: N-methyl-2-pyrrolidine 5% Triethylene glycol Monomethyl ether 10% Water * Remaining amount <Recording liquid n> Dye: CI direct black 154 1% Solvent ... Propylene glycol 10% Propylene glycol monomethyl ether 10% Water * Remaining amount <Recording liquid o> Dye ... CI direct black 22 1% Solvent ... Propylene glycol 10% Diethylene glycol monomethyl ether 5% Water * Remaining [Note] For each recording liquid In addition to the above components, 0.2% proxel (produced by ICI) was added as a preservative.

Each of the above recording liquids is heated to 60 to 80 ° C., sufficiently stirred, and then pressurized with a membrane filter having a pore size of 1 μm to be used as the recording liquid. Table 1 shows the measurement results of the surface tension of each recording liquid at 100 ° C. after the water was evaporated.

Commercially available medium quality paper shown in Table 2 was preheated and heated to 130 ° C. using the ink jet apparatus shown in FIG. 1 to perform ink jet recording of the recording liquid. Ink jet recording uses a piezoelectric control method to apply a recording liquid with a diameter of about 100 μm to about 4 m / sec.
At a speed of 速度, and adhered to the recording paper.

Table 3 shows the result of examining the recording state.

As shown in Table 3, it can be seen that the surface tension at 100 ° C. of the mixture of the solvent and the dye has a difference in bleeding at 35 mNm ⁻¹ . That is, as shown in the examples, the ink having the surface tension at 100 ° C. of 35 mNm ⁻¹ or more was able to obtain good printing without bleeding on each recording paper.

〔effect〕

According to the present invention, recording droplets adhered onto a preheated and heated general-purpose recording medium are transferred to a recording medium by capillary action or the like because the solvent and dye remaining after evaporation of water immediately after adhesion maintain a high surface tension. Is difficult to diffuse and absorb. Accordingly, by performing heating and fixing in a state of being raised, high-quality ink jet recording can be performed without causing unnecessary bleeding of the recording liquid, paper wrinkles, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of a recording apparatus used in the ink jet recording method of the present invention. Figure 2 shows the first
FIG. 2 is a partial side view of the device shown in the figure. FIG. 3 is a schematic diagram showing the overall configuration of a second embodiment of a recording apparatus used in the ink jet recording method of the present invention. FIG. 4 is a partial side view of the apparatus shown in FIG. FIG. 5 is a graph showing a change in a residual amount after a recording liquid is adhered on a recording medium.

Claims (1)

(57) [Claims] 1. A recording liquid adhered to a general-purpose recording medium such as a commercially available medium quality paper heated to 80 to 140 ° C., and a liquid component having a high vapor pressure in the recording liquid is rapidly vaporized to form a colorant and a solvent. An ink jet recording method for fixing a residual component containing: wherein the surface tension of the residual component at 100 ° C. is 35 mNm ⁻¹ or more.