JPH06329966A - Ink, ink jet recording with the ink and apparatus therefor - Google Patents

Abstract

(57) [Abstract] [Purpose] Excellent printability, especially water resistance, and even if the ink is released into the natural environment due to some factors, it is decolorized and decomposed by the decomposition action of microorganisms and reduced to a safe substance. To provide an ink excellent in environmental protection capable of avoiding the above-mentioned colored contamination, an inkjet recording method using the ink, and a device. In an ink containing a recording agent and a liquid medium for dissolving or dispersing the recording agent, the recording agent comprises a composition in which a biodegradable polymer substance is coordinate-bonded to a solubilizing group of a water-soluble dye. ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument such as a felt-tip pen, a ballpoint pen, and a line marker, and a printer for recording characters and images for the purpose of environmental protection.
The present invention relates to an ink used in a copying machine, a facsimile, a plotter, particularly an inkjet recording device, an inkjet recording method using the same, and a device using the ink.

[0002]

2. Description of the Related Art Conventionally, in the field of ink jet recording using a water-based dye ink, weather resistance (light resistance, water resistance,
Ozone resistance) has been studied. Therefore, various efforts have been made to improve the weather resistance of the dye itself which is a coloring material. For example, solubilizing groups (-OH, -S in dye molecules)
Water resistance is improved by reducing the number of O ₃ H, —COOH, etc.). However, since these dyes have low water solubility, they are stable at relatively high pH, and the pH range of environmental water (p
H = 5.8 to 8.6) has a property of easily precipitating. Therefore, when the ink using this dye is released to the environment due to some factor, the dye may be deposited and deposited on the soil or on the riverbed, lakebed or seabed and may color the ecosystem there. On the other hand, in recent years, with the widespread use of color image recording, a large amount of highly colored ink has been used. The use amount of water-soluble color inks is increasing year by year particularly in the fields of inkjet recording and general writing instruments. In particular, it is considered that the use amount of color dyes capable of high color development will increase in the future because the quality of recorded matter is good. Furthermore, these color recordings are not often stored for a long period of time, and are generally used for a temporary purpose. That is, most of the recorded images are discharged to the environment as waste. When the above color inks are released to the environment, they are highly soluble in water and rarely deposit on the soil or the bottom of the water.In the former case, colored contamination of groundwater, and in the latter case, colored contamination and coloring also reduce the light transmittance of water. In addition, the occurrence of water-bloom causes destruction of the fish ecosystem.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make a dye biodegradable so that even if it is released into the environment, it is decolorized by the decomposition action of microorganisms and reduced to a safe substance. An object of the present invention is to provide an ink excellent in recording suitability, particularly excellent in water resistance, an inkjet recording method using the ink, and a device.

[0004]

The above object can be achieved by the present invention described below.

That is, the present invention provides an ink containing a recording agent and a liquid medium for dissolving or dispersing the recording agent, wherein the recording agent comprises a composition in which a biodegradable polymer substance is coordinate-bonded to a solubilizing group of a water-soluble dye. An ink characterized by the above, an inkjet recording method using the same, and a device using the ink.

The ink of the present invention is characterized by containing a composition in which a biodegradable polymer substance is coordinate-bonded to a solubilizing group of a water-soluble dye.

The water-soluble dye generally has a structure in which several naphthalene rings or benzene rings as shown below are bonded by an azo group and a hydroxyl group, an amino group, a sulfone group or the like is added.

[0008]

[Outer 1]

In the above structure, the solubilizing group is the sulfone group --SO ₃ , which is ionized in an aqueous solution to form a sulfonium ion, that is, an anion, and the site showing the cationic property of the biodegradable polymer is located at the sulfone group of this dye molecule. United.

For example, in the case of chitosan acetate (a figure below), which is a kind of organic salt of chitosan which is a biodegradable polymer, the amino group to which acetic acid is added exhibits a cationic property and is coordinate-bonded to the sulfone group of the dye molecule ( Figure b) below.

[0011]

[Outside 2]

When the ligand shown in FIG. 2 (b) comes into contact with the natural environment, biodegradable chitosan is first decomposed by bacteria and becomes active. At the same time, the dye skeleton that is coordinated is also subjected to the action of promoting the cleavage of the azo group by the active decomposition intermediate of chitosan. Then the fading of the dye occurred,
It is considered that the dye fragment having a shortened molecular length is included in a much longer chitosan-degrading intermediate, and eventually metabolized and degraded by bacteria together with chitosan.

The dye used in the present invention is preferably a phthalocyanine-based dye, a xanthene-based dye, an anthraquinone-based dye, a monoazo-based dye, a disazo-based dye, a trisazo-based tetraazo-based dye, which are generally used in ink jet recording apparatuses and writing instruments. Particularly, as the black dye, No. 1 shown below is used.
1-No. The structure of 6 is preferable. Although the content of these dyes in the ink varies depending on the type of the dye and the recording method, it is generally preferable that the content of the dye is 20% or less of the total weight of the ink, and 10% or less of the ink used in the inkjet recording apparatus.

[0014]

[Outside 3]

Examples of biodegradable polymers that coordinate-bond to this dye include chitosan organic acid salt, cationic starch, vinylbenzyl type cationic polymer, acrylic acid type cationic polymer, polyamine sulfone, polyallylamine and the like, but especially chitosan. Acetate and cationic starch are preferably used. The content of these biodegradable polymers can be determined from the number of solubilizing groups in the dye molecule, the coordination ratio of the polymer to be coordinated with it, the number of reactive groups in the polymer molecule and the number of structural units of the polymer, The content range is 1 wt% to 30 wt% of the dye, and more preferably 5 wt% to 10 wt%. If it exceeds this range, the dye is precipitated, which is not preferable. On the other hand, if it is less than this range, biodegradability cannot be obtained, which is also not preferable.

The ink of the present invention may contain a humectant and a solubilizing agent listed below in order to improve the performance as a recording liquid. For example, ethylene glycol, diethylene glycol, triethylene glycol, alkylene glycols such as 1,2,6-hexanetriol and propylene glycol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, monoethanolamine, diethanolamine and triethanolamine. Non-proton donating polar solvents such as alcohol amines, dimethylformamide, dimethyl sulfoxide, sulfolane, lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, glycerin, 2-pyrrolidone, N-methylpyrrolidone, Examples thereof include sorbitol and urea. The content of these inks is preferably in the range of 2 to 60% of the total weight of the ink.

When the ink of the present invention is used for ink jet recording, the addition of an alkyl alcohol such as ethanol or propanol further improves the ejectability of ink droplets and is more effective.

Further, from the viewpoint of environmental protection, biodegradation or photodegradation is expected as much as possible not only for ink but also for ink containers, enclosures of recording devices, and other parts which are conventionally composed of non-perishable materials. It is more preferable that the material is a material.

The ink of the present invention can be used as a writing tool such as a felt-tip pen and a line marker, and an ink used for a printer, a copying machine, a facsimile, a plotter for recording characters and images, and particularly, an ink jet recording system. Among them, it is particularly suitable for an ink jet recording method of a type in which the ink is ejected by the firing phenomenon of the ink due to the application of heat energy.

As a method and apparatus particularly suitable for performing recording using the ink of the present invention, thermal energy corresponding to a recording signal is applied to the ink in the chamber of the recording head, and the thermal energy generates droplets. Methods and apparatus.

An example of the construction of an ink jet recording head, which is the main part of this, is shown in FIGS.

The head 13 is obtained by joining glass, ceramic, plastic or the like having a groove 14 through which ink passes and a head substrate 15 having a heat generating portion. The head substrate 15 is a protective layer 16 made of silicon oxide or the like, an electrode 17 made of aluminum or the like, a heating resistor layer 18 made of hafnium boride or the like, a heat storage layer 19 made of silicon oxide or the like, a substrate made of alumina or the like. Twenty. When an electric signal is applied to the electrode 17 in the head having this structure, the area of the head substrate 15 indicated by h;
The ink in contact with the heat-acting portion is fired, and the pressure causes the ink droplet 24 to be ejected from the ejection port 22. The ink droplets 24 ejected from the head fly toward the recording material 25 to perform landing recording. The inkjet recording head 13 may have a plurality of ejection openings 22 formed in accordance with a desired recording density. FIG. 3 shows an example of an inkjet recording apparatus incorporating such an inkjet recording head. In FIG. 3, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end, which is in the form of a cantilever. Blade 61
Is disposed adjacent to the recording area of the recording head, moves in a direction perpendicular to the moving direction of the recording head, contacts the ejection port surface, and caps. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a shape protruding in the moving path of the recording head. The blade 61,
Moisture, dust, and the like are removed from the ink ejection port surface by the cap 62 and the absorber 63. Reference numeral 65 denotes a recording head having ejection energy generating means, which ejects ink onto a recording material facing an ejection port surface on which ejection ports are arranged to perform recording.
Reference numeral 6 denotes a carriage for mounting the recording head 65 and moving the recording head 65. The carriage 66 slidably engages with a guide shaft 67, and a part of the carriage 66 is connected (not shown) to a belt 69 driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the area adjacent to the recording area.

Reference numeral 51 denotes a paper feed section for inserting a recording material,
A paper feed roller 52 is driven by a motor (not shown). With these configurations, the recording material is fed to the position facing the ejection port surface of the recording head, and is ejected to the ejection section provided with the ejection roller 53 as the recording progresses.

In the above structure, when the recording head 65 finishes recording and returns to the home position, the head recovery section 64.
The cap 62 is retracted from the moving path of the recording head 65, but the blade 61 is projected in the moving path.
As a result, the ejection port of the recording head 65 is wiped. When the cap 62 comes into contact with the ejection surface of the recording head 65 for capping, the cap 62 moves so as to project into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same positions as those at the time of wiping. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement.

The above-described movement of the recording head to the home position is performed not only at the end of recording or at the time of ejection recovery, but also at the home adjacent to the recording area at a predetermined interval while the recording head moves in the recording area for recording. After moving to the position, the wiping is performed along with the movement.

FIG. 4 is a diagram showing an example of an ink cartridge containing the ink supplied to the recording head through an ink supply member, for example, a tube. Reference numeral 40 denotes an ink containing portion containing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof.
By inserting a needle (not shown) into this stopper 42, the ink in the ink bag 40 can be supplied to the head.
An ink absorber 44 receives the waste ink. As the ink container, it is preferable that the surface in contact with the ink is made of polyolefin, especially polyethylene.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, but may be the one in which they are integrated as shown in FIG. It is preferably used. In FIG. 5, reference numeral 70 denotes a recording unit, in which an ink containing portion that contains ink, for example, an ink absorber is contained, and the ink in the ink absorber is discharged from a head portion 71 having a plurality of orifices. It is configured to be ejected as a droplet. It is preferable for the present invention to use cellulose fiber as the material of the ink absorber. 72
Is an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head shown in FIG.
It is removable with respect to.

[0029]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Examples 1 to 5 and Comparative Examples 1 and 2) Chitosan (manufactured by Taiyo Kagaku Co., Ltd.) was dissolved in a 5% acetic acid aqueous solution and heated to an extent not boiling to obtain a chitosan acetate salt. In addition, organic acids other than acetic acid, such as succinic acid, lactic acid, and malic acid, can be used in the same manner.

Corn starch produced by Wako Pure Chemical Industries, Ltd. was dispersed in diethylaminoethyl chloride and an aqueous solution of sodium hydroxide and an aqueous solution of sodium sulfate, and the mixture was stirred at 50 ° C. for 4 hours.
Cationic starch was obtained by heating for a period of time.

The following components were mixed and filtered under pressure with a membrane filter to obtain Examples 1-5 and Comparative Examples 1-2.
Got the ink.

Example 1 C.I. I. Acid blue 9 3 wt% Diethylene glycol 15 wt% Chitosan acetate 2 wt% Ethanol 10 wt% Water 70 wt% (Example 2) C.I. I. Acid Blue 9 3 wt% 2-Pyrrolidone 8 wt% Chitosan Acetate 1 wt% 2-Propanol 10 wt% Water 79 wt% (Example 3) Dye No. 1 2 wt% Glycerin 8 wt% Chitosan Acetate 0.5 wt% Water 89.5 wt% (Example 4) Dye of 6 3 wt% Cationic starch 0.5 wt% Triethanolamine 0.5 wt% Propylene glycol 20 wt% Water 76 wt% (Example 5) C.I. I. Acid blue 9 2 wt% cationic starch 1 wt% N-methyl 2-pyrrolidone 30 wt% water 67 wt% (Comparative Example 1) C.I. I. Acid Blue 9 3 wt% 2-Pyrrolidone 8 wt% 2-Propanol 10 wt% Water 80 wt% (Comparative Example 2) Dye No. 6 3 wt% Triethanolamine 0.5 wt% Propylene glycol 20 wt% Water 76.5 wt%

A biodegradation test was conducted on the above six types of inks of Examples and comparative inks.

In the biodegradation test, as shown in FIG. 6, field soil was placed in a 2 liter beaker, and 20 inks were tested.
0 ml was added. The beaker was returned to the field where the soil was collected and buried in the state shown in FIG. It was covered with a steel can whose bottom was vented to protect it from light. After that, 100 ml of soil was sampled from the beaker every week, the ink component was washed and extracted with water, concentrated to the same dye concentration as the initial concentration, and the absorbance of the aqueous solution was measured by the Hitachi Ltd. UV-visible spectrophotometer L-4200. It was measured at.

FIG. 7 shows how the absorbance changes. The absorption wavelength shifts to the lower wavelength side as the dye decomposes, but in this experiment, the change in absorbance was traced at the initial absorption wavelength position. From FIG. 7, it was confirmed that the ink of the present invention was decolorized, that is, decomposed in the dye, in 2 to 3 weeks. On the other hand, it was found that the inks of Comparative Examples did not completely decolorize although a slight decrease in absorbance was observed.

Next, the recording suitability of each of the inks of the present invention (Examples 1 to 5) described in Examples and the inks of Comparative Examples was evaluated by the following methods.

The ink cartridge shown in FIG.
1 of ink was injected and the cartridge was loaded in the ink jet recording apparatus of FIG.

Next, printing paper Xerox 4024 paper,
A predetermined test pattern was printed on the recycled paper EW-500 paper, and the initial optical density (OD1) of the printed matter and the printed dots were observed with an optical microscope to perform a sensory evaluation of the edge sharpness.
Further, soak the printed material in tap water for 5 seconds,
After natural drying, the optical density was measured again (OD2) to evaluate the water resistance. The results are shown in Table-1.

[0040]

[Table 1] From the results in Table-1, the ink of the present invention has sufficient optical density and edge sharpness in recording suitability,
Further, it can be seen that the water resistance is considerably superior to that of the conventional ink as an effect of the coordinate bond of the biodegradable polymer to the dye molecule.

As described above, according to the present invention, the recording suitability, especially the water resistance is excellent, and even if the ink is released into the natural environment due to some factors, it is decolorized and decomposed by the decomposing action of the microorganisms and is safe. It is possible to provide an ink which is reduced to a substance and is capable of avoiding colored contamination of the environment and which is excellent in environmental protection, an inkjet recording method using the ink, and a device.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a head portion of an inkjet recording apparatus.

FIG. 2 is a cross-sectional view of a head portion of an inkjet recording device.

FIG. 3 is a perspective view showing an example of an inkjet recording apparatus.

FIG. 4 is a vertical cross-sectional view showing an example of an ink cartridge.

FIG. 5 is a perspective view of a specification in which an inkjet recording head and an ink cartridge are integrated.

FIG. 6 is a schematic diagram of a test method in Examples 1 to 5 and Comparative Examples 1 and 2 of the present invention.

FIG. 7 is a graph showing evaluation test results in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 51 Paper Feed Section 52 Paper Feed Roller 53 Paper Ejection Roller 61 Wiping Member 62 Cap 63 Ink Absorber 64 Ejection Recovery Section 65 Recording Head 66 Carriage 67 Carriage Guide Shaft 68 Carriage Drive Section 69 Drive Belt Section

Claims (16)

[Claims] 1. An ink containing a recording agent and a liquid medium for dissolving or dispersing the recording agent, wherein the recording agent contains a composition in which a biodegradable polymer substance is coordinate-bonded to a solubilizing group of a water-soluble dye. And ink. 2. The ink of claim 1, wherein the biodegradable polymeric material is a cationic chitosan organic acid salt. 3. The ink of claim 1, wherein the biodegradable polymeric material is cationic starch. 4. The ink according to claim 1, wherein the biodegradable polymer substance is contained in an amount of 1% by weight or more and 30% by weight or less with respect to the water-soluble dye. 5. An ink jet recording method for recording on a recording material by ejecting ink droplets containing a recording material and a liquid medium for dissolving or dispersing the recording material from an ejection port of a recording head according to a recording signal. An ink jet recording method, wherein the recording agent comprises a composition in which a biodegradable polymer substance is coordinate-bonded to a solubilizing group of a water-soluble dye. 6. The ink jet recording method according to claim 5, wherein the ink droplets are ejected by applying thermal energy. 7. The ink jet recording method according to claim 5, wherein the biodegradable polymer substance is a cationic chitosan organic acid. 8. The ink jet recording method according to claim 5, wherein the biodegradable polymer substance is a cationic starch. 9. The ink jet recording method according to claim 5, wherein the biodegradable polymer substance is contained in the water-soluble dye. 10. A recording unit comprising an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein the ink is the ink according to any one of claims 1 to 4. A recording unit characterized by the above. 11. The recording unit according to claim 10, wherein the head portion is a head that applies thermal energy to eject the ink droplets. 12. An ink cartridge comprising an ink containing portion containing ink, wherein the ink is
4. The ink cartridge according to any one of 4 above. 13. An ink jet recording apparatus comprising a recording unit having an ink containing section containing ink and a head section for ejecting the ink as ink droplets, wherein the ink is according to any one of claims 1 to 4. An ink jet recording apparatus, which is the ink described above. 14. The ink jet recording apparatus according to claim 13, wherein the head portion is a head that applies thermal energy to eject the ink droplets. 15. An ink jet comprising a head section for ejecting ink as ink droplets, an ink cartridge having an ink containing section containing ink, and an ink supply section for supplying ink from the ink cartridge to the head section. In the recording device, the ink is formed by the method according to any one of claims 1 to
An ink jet recording apparatus, wherein the ink is any one of the inks. 16. The ink jet recording apparatus according to claim 15, wherein the head portion is a head that applies thermal energy to eject the ink droplets.