JPS6390582A - Ink jet recording method - Google Patents

Abstract

PURPOSE:To carry out ink jet recording of high-quality image regardless of paper quality, by containing a specific lower alcohol in a specific proportion in a recording liquid, applying the resultant recording liquid onto a recording medium and drying the above-mentioned recording liquid while heating at a higher temperature than room temperature. CONSTITUTION:3-30wt% methanol, ethanol or a blend thereof is contained in a recording liquid, consisting normally of a dye, pigment, solvent, e.g. glycerol, etc., preservative, pH adjustor, chelating agent, etc., and useful for ink jet recording method. The resultant recording liquid is then used to carry out printing and the recording liquid sticking onto a recording medium is dried at a higher temperature than room temperature, preferably 80-140 deg.C.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inkjet recording method that enables high-quality recording on commercially available general-purpose recording paper such as medium-quality paper regardless of paper quality.
I do it.

[Conventional technology]

A representative series of inkjet recording equipment having means for heating and drying recording liquid is JP-A-55-69464 Q55-8.
4670, etc., the entire platen is placed inside the platen and heated by a heating element, which heats the recording paper from the back side and dries the recording liquid to eliminate unnecessary bleeding, paper wrinkles, and unfixed recording liquid. Can you record high-resolution and high-quality images by preventing stains? This is an effective means to achieve this.

[Problem that the invention seeks to solve]

However, commercially available medium-quality paper, which is a typical general-purpose recording paper, uses raw material pulp during its manufacturing process.

Because the properties vary widely depending on the composition and processing method of the mixed filler, the wire part of the paper machine, the size press, etc., the inkjet recording characteristics are completely different depending on the manufacturer's production lot and even on the front and back sides of the same paper. That is, since the absorbency of the recording liquid differs, the print quality is greatly influenced by the paper quality. The above-mentioned prior art relates only to the recording paper heating means and structure of the platen section, and is technically insufficient to realize high-quality inkjet recording on general-purpose recording paper such as P and A regardless of the paper quality. Therefore, when recording on highly absorbent paper, the vaporization and permeation of the recording liquid are significantly faster, resulting in bleeding and poor print quality; However, since most of the drying of the recording liquid is carried out only by vaporization, a long heating time is required, and printing and paper feeding speeds cannot be increased, resulting in a reduction in the performance of the recording apparatus.

Does the present invention have such problems? The purpose is to improve the quick-drying properties of the recording liquid by improving its quick-drying properties, and to achieve high-quality recording on commercially available general-purpose recording paper such as J:a paper regardless of the paper quality. The purpose of the present invention is to provide an inkjet recording method that enables the following.

[Means for solving problems]

The inkjet recording method of the present invention is characterized in that the recording liquid contains 3 to 30% methanol, ethanol, incubanol, or a mixture thereof.

The object of the present invention is achieved using the inkjet recording apparatus shown in FIG. 1.3. The same number of inkjet recording apparatuses will be explained.

Figure 1 shows the inkjet recording method of the present invention? FIG. 2 is a schematic overall configuration diagram showing a first row of recording apparatuses provided therein.

In FIG. 1, the recording head 5 is guided by a carriage guide 6 and moves in the direction of arrow I 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 arrow I while being guided by a carriage guide 6. Inkjet recording is performed on recording paper that is fed by an intermittent line feed in synchronization with the recording head 5 by the a-ler 4.

In FIG. 2, the recording head 5 has a plurality of recording liquid ejection ports 1.
3, and one row of recording heads 5, which form dots @ on the recording paper 3 by a recording liquid ejecting means such as piezoelectric element control, electric field control, charge control, or thermal inkjet recording, has an interval of 0.141. The recording head uses a piezoelectric element control system and has recording liquid discharge ports arranged in a vertical row at a y pitch, and discharges recording liquid droplets of approximately 0.5 μ2 in size.

It is appropriate for fixed platen 1 to be made of a material with good heat diffusion such as aluminum alloy or heat conductive plastic material.

In this example, the average plate thickness is 1&I, approximately 250 w x 30 l
An aluminum alloy plate of J size is used. As shown in FIG. 2, on the back side of the fixed platen 1 that does not face the recording head 5, five PTC thermistors for heaters with a rated voltage power V normal temperature average resistance nΩ are equally arranged. or 10 (M7250W sheath heater, etc.) is appropriate.

The fan 17 is configured to prevent water vapor generated in the recording paper as the recording paper 3 is preheated and heated, water in the recording liquid adhering to the recording paper, or steam from a bath agent to the recording head 5, the curl removal roller 14, or the paper. In order to prevent the steam from adhering to the presser foot 7 or guide roller 4, cooling, and condensation, the steam is exhausted to the outside of the recording apparatus. Also,
This promotes the evaporation of the printing liquid F'L ratio.

Returning to FIG. 2, the recording paper 3 is in sliding contact with the fixed platen l heated by the heating element 12, and is preheated and heated by contact heat transfer before and after inkjet recording, and the recording liquid recorded by the inkjet is transferred to the recording surface immediately after it is attached. 1 Paper presser 7 is used to obtain a good print quality by preventing unnecessary bleeding of dots, paper wrinkles, and stains caused by unfixed recording liquid by rapidly drying the paper. At the same time, the recording paper 3t is brought into close contact with the fixed platen 1 to enhance the heat conduction effect.

Preheating/heating the recording paper 3 causes the recording paper 3 to curl along the shape of the fixed platen 1. In order to remove this curl, the recording paper 3 is wound around a curl removing sheet roller 14 after inkjet recording, and the curl is removed by rolling it in the opposite direction to the curling direction, and the recording paper 3 is kept in a flat state. It can be taken out.

Figure 3 shows the inkjet recording method of the present invention? FIG. 2 is a schematic overall configuration diagram showing a second row of recording apparatuses provided with the recording apparatus.

The recording head 5 is guided by a carriage guide 6 and moves in the direction of arrow I, and performs inkjet recording on the recording paper 3 which is intermittently line feed fed in synchronization with the recording head 5 by the stripe feed roller 2 and the guide roller 4. The light radiation K from the heat source lamp 18 is, for example, a paraboloid, % ellipsoid,
A curved surface such as a hyperboloid? The recording paper 3 is
The recording portion of the surface is irradiated with focused light in a heating range that extends before and after recording, and is heated by width-thickness heat transfer. In addition, the air flow sent from the blower passes through the air inlet path 25 as shown by arrows (■) and (■), and is sent to the Langhaus section consisting of the reflective plate 1, the reflective side plate O, 22b, and the transparent protective glass O. The heat source lamp 18 and the Langhaus section are cooled with air. The air flow after cooling is discharged from the air outlet n to the recording surface of the recording paper 3 through the air exhaust passages 26t-IV and 26t-V, and absorbs the convective heat and conductive heat generated by the heat source lamp 18. Heat is transferred to the surface of the recording paper.

The recording head 5 has a plurality of recording liquid discharge ports 1 as shown in FIG.
3 is provided, piezoelectric element control, electric field control, load vtl! i
Is the dot image created by recording liquid ejection control means such as control? The image is formed on recording paper 3 to record the image.

In this example, a piezoelectric element is used, and the pitch is 1 vertically at a pitch of 0.141 m.
It has rows of recording liquid ejection ports and discharges recording liquid droplets of approximately 0.5 μ2 in size.

The heat source lamp 18 is an incandescent lamp such as a halogen lamp, or an infrared lamp such as a xenon lamp, and one row uses a rod-shaped halogen lamp of 200 W and a total length of 250,113 mm. The recording width of recording paper 3 is 220u.
The heat generating lamp 18 is set at a distance of 60 m from the paper feed roller 2, and the heating range 2 is set at a distance of 60 m from the paper feed roller 2.
The heating state of the recording paper 3, which is heated by radiation 8, is detected by the temperature sensor 4 as shown in FIG.
A built-in comparison circuit compares the temperature with the set temperature, and feeds back the amount of light to maintain the temperature of the recording paper 3 almost at the set temperature. Although the temperature sensor 29 is provided on the front side of the recording paper 3 in the figure, it may be provided on the back side of the recording paper 3. Also, the set temperature can be freely controlled by the user according to the paper quality.

The blower device is a fan with an air flow rate of about 3 m''.The air flow discharged from the air outlet n is designed with consideration given to the flow direction rather than affecting the discharge of the recording liquid.Light-shielding cover 2
1 prevents light radiation from directly hitting the recording head 5 and prevents the recording head from being heated in its width and thickness. Further, the transparent protective glass prevents dust from adhering to the heat source rung 18 and the reflective head.

Appropriate preheating temperature for recording paper: If the heating temperature exceeds 140°C, the recording paper will smoke or change color.

Also, if the temperature is below 10°C, the evaporation of the recording liquid is slow and it takes a long time for the recording liquid to fix on the recording paper.

Print quality is poor. Therefore, it is desirable that the preheating temperature of the recording medium and the attached recording liquid be 80 to 140°C.

Next, the recording liquid of the present invention will be explained.

When printing on medium/earth paper, which is a general-purpose recording paper, using the above-mentioned inkjet recording device and preheating/heating the paper to 80 to 140°C, methanol, ethanol, isopropanol, or any of these may be added to the recording liquid. Adding the mixture significantly increases the rate at which the recording liquid heats and vaporizes after being layered on the recording paper, resulting in a relative reduction in the amount of recording liquid absorbed by the recording paper due to vaporization.
This is an effective means of improving printing quality because the penetration of the recording liquid, that is, bleeding, is reduced. It is effective to add 4 weight percent or more to the total weight of the recording liquid; if the weight percent is exceeded, the surface tension of the recording liquid becomes extremely low, causing bleeding and conversely deteriorating print quality. Accordingly, the recording liquid used in the present invention preferably contains methanol, ethanol, isopropanol, or a mixture thereof in an amount of 3 to 3 weight percent.

Many conventionally known dyes and pigments are effective as coloring agents. Typical dyes include various azo dyes, indigoid dyes, phthalocyanine dyes, etc.
Specifically, C1 work, direct black 19. C, engineering, direct black η, C9 engineering.

Direct Black 38, C0 work, Direct Black 154, C, work. Direct Yellow 12. C
, Engineering, Direct Yellow 26. C, Engineering, Direct Red 13. C, Eng.

Direct Red 17. C, Engineering, Direct Bruf 8
, C0 engineering, Direct Blue 90. C3 ■, Acid Black 52, C, I, Acid Yellow 5. C1 Engineering, Asiso Dread 37. C, Engineering, Acid Red 52.
C, Engineering, Acid Red 254, C, Engineering. Acid Blue 9 etc. can be used. In addition, as pigments, inorganic pigments and organic pigments with a particle size in the range of 0.01 to 3 μm can be used, and it is preferable to disperse them using a dispersant.1 The addition t of the colorant is 1.Usually 0.1 to 3 μm. It is desirable that the weight percent of IO is 0.5 to 5 weight percent, most preferably 1 to 3 weight percent, and two or more types may be added to obtain the desired hue 1.

Examples of solvents include polyhydric alcohols and derivatives thereof as wetting agents, specifically glycerin, diethylene glycol,
Thiodiglycol, triethylene glycol, polyethylene glycol φ200°300.400. Diethylene glycol monomethyl ether, diethylene glycol diethyl ether, etc. can be used. If the amount added is too small, the wetting ability of the ink will decrease and the nozzles of the inkjet head will become clogged, and if it is too large, the drying time of the recording liquid on the recording paper will be delayed, so a suitable range is 5% to 20% by weight. It is.

(9) In addition to the above-mentioned components, a preservative, a fungicide, a pH adjuster, and a chelating agent can also be appropriately added to the recording liquid used in the present invention.

[Implementation row]

The present invention will be explained in detail below.

Table - Shows typical medium- and high-quality papers used for IK printing.

Table 1 Below are shown the practical and comparative columns of the recording liquids used for printing.

■ A mixture with the composition listed in 1? Pour into a container and stir thoroughly until the pore size is 1μ.
The recording paper is filtered under pressure using a membrane filter of 1.0 m, and used as a recording acid after deaeration treatment.1 The recording paper is preheated to a surface temperature of 130°C using the recording apparatus shown in Fig. Toriji, each nozzle approximately 0.5μ
Recording droplets of No. 2 were ejected to print on the recording paper shown in Table 1. After the recording liquid was attached, heating was continued, and the area where the droplets were attached was rubbed with gauze, and the time when the recording paper was no longer stained was defined as the drying time. The results are shown in Table 3.

Regarding the print quality, f'1 Visually, there is severe bleeding, making it impossible to distinguish one character. × Smearing is visible and it is difficult to read one character. Δ There is little blurring, making it easy to read one character. O There is almost no bleeding, and it is preferable.

〔Effect of the invention〕

According to the inkjet recording method of the present invention, since the recording liquid adhering to the recording paper dries extremely quickly, it is possible to record high image quality on general-purpose recording paper such as commercially available paper and synthetic paper regardless of the paper quality. This eliminates the possibility of staining the paper with undried recording liquid, thus making it possible to increase the printing speed of the inkjet recording apparatus. Furthermore, most of the drying of the #tk liquid is due to vaporization rather than penetration into the recording paper, so it does not cause paper wrinkles in high-density recording such as artist's hard copies and color printing, and is highly effective. .

[Brief explanation of the drawing]

Figure 1 shows the inkjet recording method of the present invention? FIG. 2 is a schematic diagram showing a first row of recording devices provided therein; FIG. 2 is a partial side view of FIG. 1; FIG. 3 is a schematic overall diagram showing a second example of a recording apparatus equipped with the inkjet recording method of the present invention, and FIG. 4 is a partial side view of FIG. 3. Figure 2 above

Claims (1)

[Claims] In an inkjet recording method in which a recording liquid deposited on a recording medium is heated at a temperature higher than room temperature to dry the recording liquid, the recording liquid may contain 3 to 30 weight percent of methanol, ethanol, isopropanol, or a mixture thereof. Characteristic inkjet recording method.