JPS582365A - Recording solution - Google Patents

Abstract

PURPOSE:A recording solution having proper ink properties, jet stability, jet response, and continuous recording characteristics, obtained by adding an N alkyl-substituted derivative of propyleneurea to a recording solution consisting of a recording agent and a solvent to dissolve it. CONSTITUTION:(C) An N alkyl-substituted derivative of propylene-urea shown by the formula (R1 and R2 are H, 1-4C alkyl, preferably both R1 and R2 are methyl) as an essential component is added to a recording solution consisting essentially of (A) a recording agent (preferably water-soluble direct dye, basic dye, acid dye, etc.) and (B) a solvent for dissolving it (preferably butyl alcohol, diethylene glycol, etc.), to give the desired recording solution. Preferably the amounts of the components A and C are 40-0.5wt% and 10-70wt% respectively. EFFECT:A solid substance slightly occurs during preservation or suspension of a recorder. Providing a clear and high-contrast image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording liquid, and particularly to a recording liquid that is ejected from an ejection port provided in a print head and is ejected as droplets for printing.

Non-impact recording methods have the advantage of generating little noise during recording, and have been actively researched recently. Among these, the so-called inkjet recording method, which enables high-speed recording and can record on so-called plain paper without the need for special fixing treatment, is an extremely powerful surface recording method.
Until now, various recording methods have been devised, some of which have been improved and commercialized, and efforts are still being made to put some into practical use.

In such an inkjet recording method, recording is performed by causing a recording liquid called ink to fly in the form of a droplet stream and attaching it to a recording member such as paper. The recording liquid is usually formed by dispersing or dissolving various dyes or pigments as a recording agent in a liquid medium such as water or an organic solvent.

Various methods have been proposed for such recording methods, depending on the method of generating recording liquid droplets and the method of controlling the flight direction of the recording liquid droplet flow. In either method, physical properties such as viscosity, surface tension, and electrical conductivity are required for the recording liquid used, depending on the method of generating droplets and the method of controlling the flying direction of droplets. Ru.

An example of such a device is described below.

For example, FIG. 1 shows an apparatus that performs recording by applying a recording signal to a recording head having a piezo vibrator and generating a droplet flow of recording liquid in response to the signal. In FIG. 1, reference numeral 1 denotes a recording head, which includes a vieso element 2a, a diaphragm 2b, a recording liquid inlet 3°, a chamber 4 in the head, and an ejection port (ejection orifice).
5. Incidentally, in order to improve the recording speed, a plurality of recording heads as described above may be provided.

The liquid 7 stored in the storage tank 6 is supplied into the chamber 4 through a supply pipe 8a. In some cases, an intermediate means 9 such as a pump or a filter may be provided in the middle of the supply pipe 8a. A recording signal S converted into a pulse by a signal processing means (for example, a pulse converter) 1O is applied between the piezo element 2a and the diaphragm 2b, and the pressure changes in the recording liquid in the chamber 4 according to the signal. arises. As a result, the recording liquid 7 flows from the ejection orifice 5 into the droplet I.
J is ejected, and the blood is recorded on the recording member 12.

In addition, there is a method in which the recording liquid is electrostatically attracted and the generated droplets are controlled by an electric field in accordance with a recording signal. Application 1. Also known are systems in which recording is performed by generating and atomizing droplets using a continuous vibration generation method.

In any of these methods, in order to perform recording faithful to the recording signal, droplet generation and flight must occur stably and in accordance with the recording signal.

For this purpose, the recording liquid must first have appropriate physical properties (viscosity, etc.).

surface tension, specific resistance value, etc.).

In addition to satisfying the above conditions, the recording liquid is also required to maintain solid content during long-term storage or during recording suspension periods.

That is, if the recording liquid contains solid content, the discharge orifice will become clogged and the discharge will stop, which is not practical in terms of maintainability.

In addition, even if the ejection is not stopped, solid matter may adhere to the ejection orifice, adversely affecting the uniformity of the droplets or the stability of the flight direction of the droplets, resulting in poor ejection stability, ejection response, and continuity. Recordability may deteriorate.

The causes of this phenomenon include vaporization of the liquid medium components in the recording liquid and precipitation of non-volatile components, chemical changes in the recording liquid components to form solids, or the formation of mold. For example, solid matter is generated.

Changes in the constituent components of the recording liquid are not only due to the generation of solid content, but also to changes in ejection stability and ejection response as a result of physical property values that were adjusted to an appropriate range at the time of recording liquid formulation falling outside of that range. , it may lead to deterioration of continuous recording performance, etc.

Furthermore, what is important in inkjet recording is that the image obtained by recording must be clear, have high contrast, and be of high quality. For this reason, conventional recording liquids contain a sufficient amount of recording agent to obtain images with as high a contrast as possible.

However, even if the content of the recording agent is increased, a high quality image may not always be obtained.

In other words, when the content of the recording agent is increased, even if a small amount of the liquid medium evaporates during continuous recording or when recording is stopped, a part of the recording agent tends to precipitate as a solid substance, causing the orifice or recording liquid device to This will cause clogging of the internal flow path, etc.

Many proposals have been made in the past to satisfy the various conditions mentioned above, but most of them are improvement methods that focus on one of the many conditions; Very few recording liquids have been obtained that satisfy these conditions.

For the purpose of preventing the liquid medium from vaporizing and clogging the discharge port, the filter contains polyhydric alcohols or derivatives of polyhydric alcohols such as polypropylene glycol, ethylene glycol, diethylene glycol, glycerin, and methylcarpitol. It is known to be used as a wetting agent. However, in order to make the liquid medium difficult to open for a long period of time, a considerable amount of polyhydric alcohols is required. This causes problems such as it becomes extremely difficult to keep the viscosity (viscosity) within an appropriate range depending on the recording method.

In addition, in order to contain a sufficient amount of recording agent in the recording liquid to obtain clear, high-contrast images, formamide,
It is also known to use N-vinylpyrrolide 7 and the like as a recording agent solubilizing agent. However, even when these compounds are used, they have a high solubilizing ability for various dyes, are compatible with various liquid medium components at a wide range of mixing ratios, and furthermore, the physical properties can be increased by mixing these components. Conditions such as no fluctuation are not always satisfied, and in reality, the combinations of dyes, liquid medium components, etc. are sometimes restricted.

The present invention has been made in view of the above points, and it is an object of the present invention to obtain a recording liquid that satisfies all the necessary conditions.

That is, the main object of the present invention is to obtain a recording liquid that is excellent in ejection stability, ejection response, and continuous recording performance.

Another object of the present invention is to obtain a recording liquid that can easily have appropriate physical properties.

Another object of the present invention is to obtain a recording liquid that is less likely to generate solid content during a storage period or during a recording suspension period.

Another object of the present invention is to obtain a recording liquid which can have a wide degree of freedom in selecting constituent components and is excellent in versatility and practicality.

The present invention achieves these objects by providing a recording liquid mainly composed of a recording agent and a liquid medium for dissolving or dispersing the recording agent, which contains an N-alkyl substituted derivative of propylene urea. It is characterized by:

If the N-alkyl-substituted derivative of propylene urea is contained in the recording liquid as described above, the storage stability will be improved.

In addition to being excellent in versatility and maintainability of the device, good results can also be obtained in terms of ejection stability, ejection response, and long-term continuous recording performance. Furthermore, the solubilizing ability of the recording agent is large, and a clear, high-contrast image can be provided, resulting in an extremely practical recording liquid.

The recording liquid of the present invention consists of a liquid medium as a carrier for a recording agent, a recording agent for forming a recorded image, and additives added as necessary to obtain desired characteristics. Alkyl-substituted derivatives are considered essential components. A compound represented by the following derivatives, where ax and Rt are generally selected from (1) (or an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 21 carbon atoms, particularly preferably both a methyl group) (Both methyl ones are D below)
(referred to as MPU) is desirable.

In the present invention, in addition to using the above compound alone as a liquid medium component,
It can be used by mixing with water or the following non-aqueous liquid medium that has been commonly used in the recording field related to the present invention.

5uLId methyl alcohol, ethyl alcohol.

n-propyl alcohol, Improvil alcohol. n
-butyl alcohol, 5ec-methyl alcohol,
Alkyl alcohols having 1 to 10 carbon atoms such as tert-phthyl alcohol, isophthyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol; Examples: Eva, cyclopentane, hexane, cyclohexane, Heptane, octane, nonane, decane.

Aliphatic or aromatic hydrocarbon solvents represented by undecane, toticane, tridecane, tetralin, decalin, benzene, toluene, xylene, etc.; for example, carbon tetrachloride, trichloroethylene.

Halogenated hydrocarbon solvents such as dichloroethane and dichlorobenzene; ether solvents such as ethyl ether, butyl ether, ethylene glycol diethyl ether, and ethylene glycol monoethyl ether; examples include acetone.

Methyl ethyl ketone, methyl propyl ketone.

Ketone solvents such as methyl amyl ketone and cyclohexanone; ethyl formate and methyl acetate.

Ester solvents such as ethyl acetate, propyl acetate, butyl acetate, phenyl acetate, ethylene glycol monoethyl ether acetate, and ethyl lactate; polyhydric alcohols such as ethylene glycol, diethylene glycol, flopylene glycol, and glycerin; other amines, and amides Examples include various types of solvents such as solvents and the like.

These listed liquid media are appropriately selected and used so as to satisfy the compatibility with the recording agent and additives used and the above-mentioned properties as a recording liquid. Within the range in which a recording liquid having the characteristics can be prepared,
Two or more types may be mixed as appropriate.

Among the above-mentioned non-aqueous liquid media, water-soluble ones can be preferably used, and specific examples include alkyl alcohols having 1 to 4 carbon atoms such as ethyl alcohol, furoyl alcohol, and methyl alcohol; Ethylene glycol monoethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether.

Ether solvents such as diethylene glycol monoethyl needle, ') ethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol motuptyl ether; Alcohol; ethanolamine, ′) ethanolamine, triethanolamine,
Examples include amine-based or amide-based solvents such as formamide, N-, methyl-2-pyrrolidone, dimethylformamide, and diethylformamide; and ester-based solvents such as ethyl lactate and ethylene glycol monoethyl ether.

A preferred mixing form in the present invention is a system in which the above-mentioned DMPU is mixed with water or water and a water-soluble non-aqueous liquid medium, and examples include the following (1) to (9). .

(1) Water/DMPU system (2) Water/alkyl alcohol/l) MPU system (3)
Water/Polyhydric alcohol/DMPU type (4) Water/
Polyhydric alcohol / Alkyl alcohol / DMPU system (5) Water / Ether solvent / DMPU system (61 Water / Ether solvent / Polyhydric alcohol ZDMPU system (7) Water / Amine or amide solvent / I) MPU system (8 )Water/ester solvent/DMPU system (9)Water/ester solvent/polyhydric alcohol ZDMPU system Among these, conditions such as recording performance, versatility, ease of adjusting liquid physical properties, pollution resistance, etc. were taken into consideration. In this case, (3) to (9)
), especially (3), (5), (6) and (9)
The type is preferred.

The content of the propylene urea derivative varies considerably depending on the type of liquid medium used, the range of desired physical property values, etc., but it is generally 10% of the total weight of the recording liquid.
% to 90%, preferably 10% to 70 tl), particularly preferably 10% to 60%.

As a recording agent, the relationship with the liquid medium and additives should be carefully controlled to avoid sedimentation, agglomeration, and clogging of the discharge orifice due to long-term storage indoors or in the recording green liquid tank. be used selectively.

The recording agent that can be used in the present invention is appropriately selected depending on the recording material so as to fully meet the recording conditions, but many conventionally known dyes and pigments are effective. It is.

The dyes that can be effectively used in the present invention are those that can satisfy the above-mentioned characteristics of the prepared recording liquid, and generally include direct dyes, basic dyes, acid dyes, and soluble dyes. Vat dyes, acid mordant dyes, mordant dyes, sulfur dyes, vat dyes.

In addition to alcohol-soluble dyes, oil-soluble dyes, 9-disperse dyes, etc., threne dyes,
Examples include water-soluble or oil-soluble dyes such as naphthol dyes, 1-reactive dyes, chromium dyes, 2-type complex salt dyes, 1:1-type complex salt dyes, azoic dyes, and cationic dyes.

Among these numerous dyes, water-soluble direct dyes,
Basic dyes or acidic dyes are particularly preferably used.

These dyes are appropriately selected as desired and used after being dissolved or dispersed in the liquid medium used.

Pigments that can be effectively used in the present invention include many inorganic pigments and organic pigments.

The quantitative relationship of these recording agents is 50% to 0.5%, preferably 40% by weight, based on the total weight of the recording liquid.
% to 0.5%, and more preferably 30% to 1%.

As the recording agent, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or poorly soluble in the liquid medium, the particle size of the recording agent when dispersed in the liquid medium may vary. If it is made small enough, it can be used. In this case, the particle size of the recording agent is usually 3 to 0.01μ, preferably 2 to 0.01μ,
More preferably 1 to 0. It is in the range of O1μ. Furthermore, it is preferable that the particle size distribution of the dispersed recording agent be as narrow as possible.

The N-substituted derivative of propylene urea of the present invention exhibits a function of improving the solubility of recording agents, particularly dyes, in the liquid medium,
The concentration of the recording agent in the recording liquid is increased, and the images obtained with the recording liquid are clear, high-contrast, and high-quality.

In terms of the effect of increasing the solubility of the recording agent, it is generally accepted that the content of the N-substituted derivative of propylene urea is 0.5% or more based on the total weight of the recording liquid, and 5% or more. It becomes especially noticeable.

The recording liquid of the present invention prepared in this manner exhibits many excellent properties. That is, N-substituted derivatives of propylene urea, especially D
When MPU is present in the liquid medium component, it has a high solubility with various liquid medium components, and the physical properties of the liquid can be easily adjusted. It is small in size, and its physical properties do not deviate significantly from the appropriate range even with slight changes in environmental conditions. Alternatively, a liquid medium component containing an N-substituted derivative of propylene urea has a remarkable affinity for many dyes used as recording media, and is capable of dissolving sufficient amounts of dye on scales and preventing volatilization of the component. It has the advantage of being less likely to cause solid content.

In this way, the recording liquid of the present invention not only has excellent ejection stability, ejection response, droplet uniformity, and continuous recording performance, but also has excellent image quality, storage stability, maintainability of the device, and component composition. It also exhibits excellent properties in terms of freedom of selection.

The recording liquid of the present invention, which has the above-mentioned components as its basic constituents, has excellent properties in itself, but various additives may be added in order to provide even more remarkable recording properties. Examples of such additives include viscosity modifiers, surface tension modifiers, PH modifiers, resistivity modifiers, and the like.

In this way, the recording liquid of the present invention is given desired physical properties and can be used in various inkjet recording apparatuses. For example,
In addition to the recording device shown in FIG. 1, as shown in FIG. ,
A device used for recording by electrostatically attracting a recording liquid and controlling the generated droplets with an electric field according to a recording signal, which generates droplets with a controlled amount of charge using a continuous vibration generation method. , a recording device used for recording by making the droplet fly between deflection electrodes to which a uniform electric field is applied, or a recording device that applies a recording signal in the form of thermal energy to the recording liquid in the recording head to cause the droplet to fly. It may also be used in a recording method that generates a signal.

The present invention will be specifically explained with reference to the following examples.

Example 1 - The above composition was stirred until it became sufficiently uniform and filtered under pressure using a 045μ Fluorobore filter (manufactured by Sumitomo Electric Industries, Ltd.) to obtain a recording liquid (A-1).

Then, the recording liquid (A-1) was transferred to a beaker, stored in a vacuum drying box, evacuated, and degassed for 2 hours.

20 ml of the recording liquid (A-1) obtained in this way
It was then stored in a cassette container made of vinylidene chloride and sealed.

Thereafter, the target container was set as a storage tank of the recording apparatus shown in FIG. 3, and recording was carried out under the recording conditions shown in Table 1, and the recording performance, storage stability, and quality of the recorded images were examined as shown in Table 2.

The recording device shown in FIG. 3 is a modification of the recording device shown in FIG. The mechanism etc. are the same as the device shown in FIG.

As shown in Table 2, the liquid (A-1') of this example has excellent practical recording performance and storage stability, and is clearly capable of providing high-quality images.

For comparison, recording liquid (A-1) was treated in the same manner as recording liquid (8-1), except that glycerin, which is commonly used as a drying inhibitor for general inks, was used instead of DMPUQ in recording liquid (A-1). A,-2) was prepared. After that, the recording liquid (
A-2) The results are shown in Table 2.

Table 1 In addition, the amount of DMPUO in the recording liquid (A-1) was 35 parts by weight,
When a recording liquid was prepared in the same manner except that the amount of ion-exchanged water was changed to 61 parts by weight, and the same study was conducted, good results were obtained in terms of recording performance and image quality.

Example 2 The above composition was stirred sufficiently uniformly with a glass of water, and the following Example 1 was prepared.
According to the same procedure as above, recording liquid (B-1) was prepared and filled into a storage tank.

Thereafter, recording performance, storage stability, and image evaluation were performed on the recording liquid (B-1) in the same manner as in Example 1 using the recording apparatus shown in FIG. Note that the recording conditions are shown in Table 3.

As shown in Table 7, good results were obtained.

The results of Examples 3 to 5 below are also summarized in Table 6.

Table 3 Example 3 The above components were stirred until sufficiently uniform, and the following Example 1 was prepared.
Recording liquid (C-1) was prepared according to the same procedure as above, and then filled into a storage tank.

Thereafter, the recording liquid (C-1) was tested for recording performance, storage stability, and
and image evaluation.

The recording device shown in Fig. 2 is a device that uses electrostatic suction force to fly the recording liquid to which a certain static pressure is applied, forming droplets. When a voltage (bias voltage approximately 2, I KV) is applied and a human input signal (approximately 5 ooV) corresponding to the recording signal is applied, the applied voltage becomes the threshold voltage for 'flll IY4 generation (approximately 2 KV). .5KV), and droplets begin to form.

Good results were obtained as shown in Table 7.

Table 4 The above composition was stirred until it became sufficiently homogeneous, and the following Example 1
Following the same procedure as above, the recording liquid (I)-1) was prepared and then filled into the storage tank.

Thereafter, a glass nozzle having a discharge orifice for discharging the recording liquid (D-1) and the recording liquid, and an electrothermal converter (
Using a recording apparatus having a recording head configured with a heating element), the recording performance 1 image quality and storage stability of the recording liquid were examined.

The recording conditions were as shown in Table-5.

As shown in Table 7, good results were obtained.

The above composition was stirred until it became sufficiently uniform, and the following Example 1
According to the same procedure as above, recording liquid (W-1) was prepared and filled into a storage tank.

Thereafter, recording performance, storage stability, and image quality were examined in the same manner as in Example 1 using the recording liquid (E-1). Vote the results in Table-7. As in Example 1, good results were obtained.

Example 6-10 The compositions shown in Table 6 below were stirred until they were uniformly coated, and following the same procedure as in Example 1, recording liquid (E-1) was prepared.
), (F-1), (G-1).

(H-1) and (1-1) were prepared and subjected to the same procedure as in Example 1 to examine recording performance, storage stability, and image quality. The results are shown in Table-7.

In both examples, in terms of recording performance, storage stability, and image quality,
Very good results were obtained.

[Brief explanation of drawings]

1, 2, and 3 are schematic diagrams of a recording apparatus to which the present invention is applied. However, in the figure, 1... recording head, 2a... piezo element, 2b...
Vibration plate, 3... Inflow port, 4... Chamber, 5... Discharge orifice, 6... Storage tank, 7... Recording liquid, 8...
- Supply pipe, 9... intermediate processing means, 10... signal processing means. DESCRIPTION OF SYMBOLS 11... Droplet, 12... Recorded member, 13... Counter electrode. Applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. A recording liquid composed mainly of a recording agent and a liquid medium for dissolving or dispersing the same, characterized in that it contains an N-alkyl substituted derivative of propylene urea.