JPS6048553B2 - recording liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording liquid composition used for recording by ejecting a recording liquid from an ejection orifice of a recording head and flying it as droplets.

Non-impact recording methods have the advantage of generating little noise during recording, and have been actively researched recently. Among these, the inkjet recording method, which enables high-speed recording and can record on so-called plain paper without the need for special fixing processing, is an extremely powerful recording method, and has been used in various ways until now. Some methods have been devised, improved and commercialized, and efforts are still being made to put them into practical use. This type of inkjet recording method uses droplets of a recording liquid called ink.
t) is made to fly and adhere to a recording member to perform recording.

The basic components of such a recording liquid include a recording agent (dye or pigment is used) and a liquid medium for dissolving or dispersing it (water, various organic solvents, or mixtures thereof are used), and various additives are added as necessary. Additives are added. There are various types of such recording methods depending on the method of generating recording liquid droplets and the method of controlling the flying direction of the droplets.

An example is shown in FIG. That is, the apparatus shown in FIG. 1 applies a recording signal to a recording head having a piezo vibrator, and performs recording by generating droplets in response to the signal.

In FIG. 1, 1 is a recording head, and a piezo vibrator 2a
) It has a diaphragm 2b, a recording liquid inlet 3, a liquid chamber 4 in the head, and an ejection port (ejection orifice) 5. In the liquid chamber 4, a recording liquid 7 stored in a storage tank 6 is connected to a supply pipe 8.
It has been introduced by. In some cases, an intermediate treatment means 9 such as a pump or a filter may be provided in the middle of the supply pipe 8. A signal converted from the recording signal S into a pulse by a signal processing means (for example, a pulse converter) 10 is applied to the piezo vibrator 2a, and the pressure changes in the recording liquid in the liquid chamber 4 in accordance with the signal. occurs. As a result, the recording liquid 7 is discharged from the discharge orifice 5 in the form of droplets 11, and recording is performed on the surface of the recording member 12. In addition to the above-described devices, several types of devices are known that perform recording by causing recording liquid to fly in the form of droplets.

For example, as a modification of the device shown in FIG. is essentially the same as the apparatus shown in Figure 1). Further, there is also known an apparatus that has a recording head similar to that shown in FIG. 1, continuously generates droplets, and uses a portion of the droplets for recording. In this device, an electric field modulated by a recording signal is printed between the discharge orifice and a charging electrode installed in the droplet flight space in front of the discharge orifice, and the discharged droplets are charged by the electrode. be done. Further in front of the charging electrode, a deflection electrode on which a certain electric field is printed is installed, and the charged droplet is deflected to perform recording. Alternatively, there is also known a device that applies a high-voltage electric field modulated by a recording signal between an ejection orifice and a charged electrode in front of it to generate droplets using electrostatic force. There is.

Furthermore, there is also known an apparatus that applies thermal energy corresponding to a recording signal to a recording liquid in a chamber of a recording head, and generates droplets using the energy.

As described above, the methods of generating droplets and the methods of controlling the flying direction of droplets are quite different among apparatuses that perform recording by flying droplets. Therefore, in order to perform good recording, the physical properties of the recording liquid used, such as viscosity, surface tension, and specific resistance, must be adjusted depending on the method of generating droplets or the method of controlling the flying direction of droplets. required. Furthermore, the recording liquid must not contain any solid content due to vaporization of the liquid medium components or chemical changes in the constituent components during long-term storage or when recording is stopped. Generally, the ejection orifice of this type of recording device is a minute hole (generally about several 104p in diameter), so the generation of solid content may cause clogging and no droplets may be ejected at all. Furthermore, even if ejection does not stop, the generation of solid content may have a negative effect on the generation of uniform droplets or the stable flight of droplets, and may affect the recording method, ejection stability, ejection response, or continuity. Recordability may also deteriorate.

Alternatively, if the constituent components of the recording liquid undergo a chemical change, the physical properties that were adjusted to desired values at the time of compounding may change, resulting in a decrease in recording performance, ejection stability, and ejection response. Therefore, there is a need for liquid medium components that do not easily vaporize, chemically stable recording agents, or combinations of liquid medium and recording agents that do not cause the above-mentioned drawbacks. Furthermore, it is also required that the recorded image has sufficiently high contrast and clarity.

In general, with conventional recording liquids, when an attempt is made to increase the contrast of a recorded image by increasing the content of the recording agent, the ejection orifice tends to become clogged. Therefore, there is a need for a recording agent with high solubility in a liquid medium and a bright color tone. Alternatively, the image once recorded must have water resistance, light resistance, weather resistance, and abrasion resistance.

Images recorded with conventional recording liquids, especially water-based ones, tend to cause blurring or force deviation due to adhesion of water, light irradiation, or mechanical friction, and there is a strong demand for recording liquids that have improved these drawbacks. It is rare. From this point of view, many proposals regarding recording liquids have been made, but hardly any practical recording liquids that satisfy all of the above conditions have been obtained.

An object of the present invention is to provide a recording liquid that satisfies all of the above conditions. That is, clogging of the discharge orifice,
The object of the present invention is to provide a recording liquid that does not undergo deterioration or sedimentation during storage and has excellent recording performance, ejection stability, and ejection response. Another object of the present invention is to provide a recording liquid with excellent color tone and contrast of recorded images. Furthermore, it is an object of the present invention to provide a recording liquid with excellent fixing properties in which recorded images have water resistance, light resistance, weather resistance, and abrasion resistance. A recording liquid of the present invention which achieves the above object is a recording liquid composed of a water-soluble dye and a liquid medium for dissolving or dispersing the dye, in which at least one SO3NO. A metal phthalocyanine compound in which a group has been introduced and a metal atom selected from group ■, group ■, group ■, or group II is coordinated at the center of the skeleton, or a metal atom is coordinated at the center of the skeleton. It is characterized by containing a metal-free phthalocyanine compound.

When the compound is included in the recording liquid in this way, recording properties are improved.
A practical recording liquid can be obtained which has excellent ejection stability, ejection response, and continuous recording performance, and in particular has clear recorded images, as well as water resistance, light resistance, throat resistance, and abrasion resistance.

The recording liquid of the present invention contains a dye compound having a phthalocyanine skeleton as a recording agent, and the compound generally has a basic structure like a circle and (B).

However, in (2), M represents a metal atom of the Pi group, ■ group, ■ group, or ■ group, which forms a stable complex with the N atom of the phthalocyanine skeleton.

Further, an SO3Na group is introduced into the phthalocyanine skeleton, but not only one but two or more SO3Na groups may be introduced as shown in the above formula. On the other hand, (B) is
This shows a metal-free phthalocyanine compound in which no metal atom is coordinated at the center of the phthalocyanine skeleton. This type of compound also has a --SO3Na group introduced therein, as in the above-mentioned circle. The metal to be introduced into the center of the phthalocyanine skeleton is preferably a metal of the 3rd, 4th or 5th period among the metals of the group ①, group ②, group ① or group ①, particularly Mg.
、． Zn,. Sn) Mn. ．． FeNCO and Ni electrodes are preferred.

Specific examples of compounds used as recording agents in the present invention include NO. Examples include compounds represented by 1 to 18.

Among these compounds, NO. A compound in which two sulfone groups with a basic structure are introduced into the molecule,
Specifically, NO. ．． 2, 9, 12, 1 & 1 ho 17 and 1
Those represented by 8 are preferred.

The recording liquid of the present invention basically includes the above compound as a recording agent and a liquid medium for dissolving the recording agent.

As the liquid medium used in the present invention, water or a mixed system of water and a water-soluble organic solvent is preferably employed. Specifically, water-soluble organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
Alkyl alcohols having 1 to 4 carbon atoms such as Sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol; Amides such as dimethylformamide and dimethylacetamide; Ketones or keto alcohols such as acetone and diacetone alcohol; Tetrahydrofuran, dioxane, etc. When ethers, N-methyl-2-pyrrolidone, etc. are used in combination with water as effective substances, they are mixed and added in the necessary amount within a range that does not adversely affect the prepared recording liquid. . In the present invention, the amount of the compound to be added depends on the desired recording image quality, the recording method of the apparatus used for recording, the type of constituent components to be added, the required liquid physical properties, etc. Although it is determined as appropriate, it is usually 0.1 to 1 based on the total weight of the recording liquid to be prepared.
5wt%, preferably 0.5-10wt%, optimally 1-10wt%
It is desirable that the content be 8 Wt%.

By thus preparing a recording liquid using the above-mentioned compound as a recording agent, the intended object of the present invention is effectively achieved. In other words, the signal response, stability of droplet formation, ejection stability, and flowability are extremely good, and even when recording is performed continuously for a long time, the supply speed in the flow path in the device can sufficiently follow the recording speed. In addition, it has good adhesion to a recording member, and the recorded image has particularly excellent light resistance, weather resistance, and water resistance, and a clear image with high image density can be obtained in the capacity. The recording liquid of the present invention is basically composed of the above-mentioned compound and a liquid medium, but within the scope of the effects of the present invention, conventional recording agents and a third agent for adjusting the physical properties of the liquid may be added. Components may be added in required amounts.

The third component for adjusting liquid physical properties is viscosity adjustment. agent,
Examples include surface tension adjusters, PH adjusters, resistivity adjusters, etc., and further additives such as wetting agents and antifungal agents for further improving the recording liquid of the present invention. The viscosity modifier and surface tension modifier are mainly used to flow through the flow path in the device at a sufficient flow rate depending on the recording speed, to prevent the recording liquid from going around at the ejection orifice, and to apply it to the recording member. It is added to prevent bleeding (spreading of spot diameter) when

As the viscosity modifier and surface tension modifier, almost all commonly known agents can be used as long as they are effective and do not adversely affect the liquid medium and recording material used. Examples of the viscosity modifier include polyvinyl alcohol, hydroxypropyl cellulose, water-soluble acrylic resin, etc., and examples of the surface tension modifier include anionic and nonionic surfactants. Two or more types of surface tension modifiers may be mixed as necessary within a range that does not adversely affect each other or other constituent components so as to give a desired surface tension and ensure stable droplet ejection. You can use it as well.

The pH adjuster is added in an appropriate amount in order to improve the chemical stability and properties of the adjusted recording liquid, for example to prevent changes in physical properties due to long-term storage and to prevent sedimentation and aggregation of the recording agent and other components.

When recording by charging droplets of a recording liquid, the specific resistance of the recording liquid acts as an important factor in its charging characteristics.

That is, in order to charge the droplets of the recording liquid so that good recording can be performed, the recording liquid must be prepared so that the specific resistance value is usually 10-° to 10'' Ωα. In the case of recording that does not require charging of liquid droplets, the specific resistance value may be arbitrary.

As the wetting agent used in the present invention, there are many effective wetting agents such as polyhydric alcohols and ethers of polyhydric alcohols commonly known in the technical field related to the present invention.

In the recording liquid of the present invention, particularly favorable results can be obtained when a liquid medium mainly composed of water and the above-mentioned wetting agent are mixed with the dye compound represented by the general formula of the precursor.

For example, polyhydric alcohols such as polyethylene glycol, ethylene glycol, propylene glycol, methoxytriglycol, and glycerin: ethylene glycol methyl ether, diethylene glycol methyl (or ethyl)
Ethers: Suitable compounds include esters of polyhydric alcohol ethers such as ethylene glycol methyl ether acetate and diethylene glycol methyl ether acetate. These wetting agents may be used alone or in combination of two or more. Furthermore, in the present invention, a water-soluble resin polymer such as polyvinyl alcohol is added in order to obtain a film having excellent film formation properties, especially film strength when attached to a recording member. It's okay to be.

The recording liquid of the present invention has the various recording properties described above. In order to record, viscosity, surface tension, PH, etc., specific resistance when recording using charged droplets, or specific heat, heat when recording using thermal energy. It is formulated so that characteristic values such as expansion coefficient and thermal conductivity fall within specific condition ranges. In other words, these physical properties have important relationships with the stability of droplet formation, signal response and fidelity, image density, chemical stability, flowability in the flow path within the device, etc. Therefore, it is necessary to pay sufficient attention to these matters when preparing the recording liquid.

In the recording liquid of the present invention, the above-mentioned physical properties preferably have values as shown in Table 1 below. However, it is not necessary for all of the listed physical properties to satisfy the numerical conditions shown in Table 1, and some of these physical properties may be changed depending on the recording characteristics required of the recording liquid of the applied recording method. It is a good idea to obtain a value that satisfies the conditions in Table 1. *Conditions for using charged droplets As already mentioned, the recording liquid of the present invention is given desired physical properties and can be used in various types of inkjet recording methods. For example, in addition to the recording device shown in FIG. 1, as shown in FIG. 2, as a modification of the device shown in FIG.
is shaped like a nozzle, and a cylindrical piezo vibrator 2a is attached to the outer periphery of the nozzle.
A recording method that performs recording using a device installed with It is used in recording methods that generate and record data. The present invention will be specifically explained with reference to the following examples.

Example 1 Ion exchange water 6? Parts Diethylene glycol 20 N-methyl-2-pyrrolidone 15 NO. ．． Compound 3 of 4 The above components were thoroughly mixed and dissolved in a container, filtered under pressure using a Teflon (trade name) filter with a pore size of 1μ, and then
A recording liquid (1) was obtained by degassing using a vacuum pump.

T, -T using the recording apparatus shown in FIG. As a result, good results were obtained in all cases (discharge orifice diameter 60 μm, piezo vibrator drive voltage 50 V, frequency 10 KHz). (T1) Long-term storage stability of recording liquid; recording liquid (1
) was sealed in a glass container and stored at 0°C and 40°C for 6 months, no precipitation of insoluble matter was observed, and there was no change in the physical properties or color tone of the liquid. (T.

) Ejection stability: Continuous ejection was performed for 24 hours, and stable high-quality recording was possible from beginning to end. (T.) Ejection response: Intermittent ejection every 2 seconds and ejection after one month of standing were investigated, and stable and uniform recording was obtained in both cases. (T
.

) Quality of recorded images: The recorded images had high density and clarity. After three months of exposure to room light, the density decrease was less than 1%, and when immersed in water for 1 minute, there was very little blurring of the image. Examples 2 to 9 Recording liquids having the compositions shown in the table below were prepared in the same manner as in Example 1, and as in Example 1, T, -T, were examined.

In Table 2, the numbers in parentheses indicate the composition ratio. When practical recording was carried out in the same manner as in Example 1 using these recording liquids, the storage stability, ejection performance, and recorded image quality were all excellent as in Example 1.

Comparative Example No. 1 in Example 1. ．． Instead of compound 4, sodium copper phthalocyanine disulfonate (
Sirius Lighter Words GLNC. I. 74l8O)
The recording liquid was prepared in exactly the same manner as in Example 1, except that T and T were used.

We conducted a study. T: After storage at 40°C for 6 months, insoluble matter precipitated and changes were observed in the pH, viscosity, surface tension, and color tone of the liquid.

T. : After exposing the recorded image to room light for 3 months, the density reduction rate was 7%.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of the recording apparatus. However, in the figure, 1...recording head, 2a
...Piezo vibrator, 2b...Vibration plate,
3...Inflow port, 4...Liquid chamber, 5...
...Discharge orifice, 6 ...Storage tank,
7... Recording liquid, 8... Supply pipe, 9.
...Intermediate processing means, 10 ... Signal processing means, 11 ... Liquid droplet, 12 ... Recording member, S ... Recording signal be.

Claims (1)

[Claims] 1. In a recording liquid composed of a water-soluble dye and a liquid medium for dissolving or dispersing the dye, a group II, IV, or VII group in which at least one SO_3Na group is introduced into the molecule. Or
A recording liquid characterized by containing a metal phthalocyanine compound in which a metal atom selected from Group VIII metal atoms is coordinated at the center of the skeleton, or a metal-free phthalocyanine compound in which no metal atom is coordinated at the center of the skeleton. . 2. The recording liquid according to claim 1, wherein the phthalocyanine compound is contained in an amount of 0.1 to 15% by weight based on the total weight of the recording liquid.