JPH0860054A - Ink for ink jet recording, method for forming relief image using the same, and apparatus for forming relief image - Google Patents

Abstract

PURPOSE: To obtain an ink for ink jet recording which is esp. suitable for the bubble jet method, does not pollute the environment, and can form reliefimages on various recording materials by incorporating a specific photosensitive compd a solvent, and a film-forming resin as the essential components into the ink. CONSTITUTION: The ink contains as the essential components a photosensitive compd. which is pref. an azo compd. and decomposed by ultraviolet rays to produce a gas [e.g., 4-(4-methylphenylthio)-2,5-diethoxybenzenediazonium tetrafluoroboratel, a solvent which is pref. a water-sol. org. solvent capable of dissolving the photosensitive compd. (e.g., N-methyl-2-pyrrolidone), and a film-forming resin which is pref. a water-sol. thermoplastic resin having a softening point of 40-85 deg.C (e.g., polyvinylpyrrolidone).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording ink, a relief image forming method and a relief image forming apparatus using the ink, and more particularly to an ink jet method for ejecting ink by generating bubbles by an electric heat exchanger. The present invention relates to a useful ink, a relief image forming method and a relief image forming apparatus using the ink.

[0002]

2. Description of the Related Art Conventionally, ink for forming a relief image by foaming the ink by applying heat energy or the like and then solidifying the ink is used for screen printing ink or a stationery using a trainer or a T-shirt as a recording material. There are inks or base films used for bubble photography.

[0003]

However, when the conventional relief image forming ink as described above is applied to the ink jet system, particularly the bubble jet system, there are the following problems. (1) Since it has a high viscosity, it is not suitable for an inkjet method due to the characteristics of the ink. (2) Since it contains an organic solvent, it emits a solvent odor and poses a problem for the environment. (3) Since it is not a water-based ink, it is not suitable for an inkjet method, particularly a bubble jet method, due to the characteristics of the ink. (4) With regard to the stationery ink, it is necessary to heat the recording material on which an image is formed, and there is a restriction on the recording material as a target.

Therefore, the object of the present invention is to suit the ink jet system, particularly the bubble jet system, because of the characteristics of the ink.
An object of the present invention is to provide an inkjet recording ink that has no problem with the environment and can form a relief image on various recording materials, a relief image forming method and a relief image forming apparatus using the ink.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention is an inkjet recording ink characterized by containing at least a photosensitive compound which decomposes by ultraviolet rays to generate a gas, a solvent which dissolves the photosensitive compound, and a film-forming resin, and a relief image using the ink. A forming method and a relief image forming apparatus.

[0006]

According to the present invention, an ink containing a photosensitive compound, a solvent that dissolves the photosensitive compound, and a film-forming resin is used,
An arbitrary image is recorded on a non-liquid-absorbent recording material by using an ink jet recording apparatus, and by irradiating the recorded image with ultraviolet rays, a gas generated and a film formation for holding the gas in a bubble shape are formed. An excellent relief image can be formed by the action with the resin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The photosensitive compound used in the ink of the present invention is a compound that is decomposed by ultraviolet rays to generate a gas. Particularly, the generated gas is preferably nitrogen, which is harmless to the environment, and examples of the photosensitive compound that generates nitrogen include p-dimethylbenzenediazonium salt, p-diethylaminobenzenediazonium salt, and N, N-. Diazo compounds such as dimethylaminobenzenediazonium salt, photosensitive polymers obtained by adding groups such as vinylidene chloride and acrylonitrile copolymer, polymethylmethacrylate and the like to groups such as N, N-dimethylaminobenzenediazonium salt, these diazonium salts and zinc chloride And double salts with borofluoride salts and the like.

A preferred solvent for dissolving the above-mentioned photosensitive compound is a water-soluble organic solvent such as isopropyl alcohol (IPA), thiodiglycol, ethylene glycol, N-methyl-2-pyrrolidone, polyethylene glycol and ethanol. Among these, IPA, ethanol and ethylene glycol also have the action of promoting the decomposition of the photosensitive compound and the generation of gas. Therefore, in the present invention, the decomposition of the photosensitive compound together with the solvent for dissolving the photosensitive compound is carried out. Also, it is preferably used in combination with a solvent having an effect of promoting gas generation. These water-soluble organic solvents may be used alone or as a mixture of two or more, and it is also preferable to use them in mixture with water. When used by mixing with water, it is preferable that water accounts for about 1 to 40% by weight in the mixed solvent.

The film-forming resin preferably used in the ink of the present invention is, for example, polyvinyl alcohol, polyvinylpyrrolidone (PVP), hydroxypropylmethyl cellulose, polyacrylamide, aqueous vinyl urethane, polyethylene oxide, acrylic copolymer, Water-soluble thermoplastic resins such as polyvinyl ether, polyacrylic acid, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, polypropylene glycol and carboxymethyl cellulose can be mentioned. It is preferable to use a thermoplastic resin having a softening point of 40 to 85 ° C. as the film-forming resin. If the softening point is too low, the strength of the relief image formed will be insufficient, and if the softening point is too high, foaming due to the generated gas will be insufficient, and a good relief image cannot be obtained in any case.

As the performance required for ink in forming a relief image, a relief image is stably formed by a gas generated by decomposition of a photosensitive compound, and the formed relief image has optimum strength and unevenness. It can be cited as having. Therefore, as a result of intensive studies to satisfy these performances, the present inventors have found that the amount of the photosensitive compound dissolved in the ink is 0.9 to 7 with respect to the total weight of the ink.
It has been found that a stable relief image can be formed in the range of 0% by weight, preferably in the range of 40 to 60% by weight.

When the amount of the photosensitive compound is less than 0.9% by weight based on the total weight of the ink, the amount of gas generated by the decomposition of the photosensitive compound is too small, and conversely, when it exceeds 70% by weight. Is not preferable because the relief image formed by the film-forming resin is destroyed by the generation of excessive gas, and a stable relief image and a relief image with an optimum strength cannot be obtained.

The photosensitive compound dissolved in the ink and the film-forming resin are used in a weight ratio of 1: 4 to.
It has been found that a relief image having optimum strength and unevenness is formed by setting the ratio to 7: 1, preferably 2: 1 to 6: 1. The reason is due to the relationship between the amount of gas generated and the intensity of the relief image formed by the film-forming resin.

Further, the amount of the water-soluble organic solvent for accelerating the generation of gas is set in the range of 10 to 85.5% by weight, preferably 40 to 60% by weight, based on the total weight of the ink, to stabilize the composition. It was found that a relief image was formed. When the amount of the above water-soluble organic solvent is less than 10% by weight based on the total weight of the ink, sufficient relief images cannot be obtained due to insufficient generation of gas, while more than 85.5% by weight. In this case, the excessively generated gas causes destruction of the formed relief image, which is not preferable.

In addition to the above components, the ink of the present invention comprises
For example, coloring materials of various hues such as direct dyes, acid dyes, basic dyes and reactive dyes can be used in combination. Also, if you want to form a relief image of two or more colors,
The inks may be prepared and used by using two or more color materials. A color relief image can be easily produced by an inkjet recording apparatus having a recording head having a plurality of ejection holes using these plural colors of ink.

The relief image forming method using the ink of the present invention comprises (1) a first step of cleaning the surface of a non-absorbent recording material, if necessary, and (2) an ink jet recording method. According to the image recording signal, the ink droplets of the ink are ejected from one or a plurality of ejection holes of the recording head, and the ink droplets are applied to a predetermined position of the recording material to form a recording image. The second step, and (3) the solvent in the ink image applied on the recording material is removed by hot air or standing, and then the ink image is foamed and solidified by ultraviolet irradiation to form a relief image. And a process.

In addition, the second method of forming a relief image of the present invention
In the step (1), the inkjet recording method is preferably a bubble jet recording method. In the relief image forming method of the present invention, the first step of cleaning the surface of the recording material includes methods such as UV / O ₃ cleaning and alcohol cleaning. It may be omitted depending on the surface condition of. The recording material used in the present invention needs to be non-absorbent to ink. When the recording material is a liquid absorbing material such as plain paper or woven cloth, it is difficult to form a relief image because the applied ink is absorbed in these recording materials. Preferable recording materials include, for example, plastic film, plastic sheet, plastic molded product, metal sheet, glass, resin-impregnated paper and the like.

As shown in FIG. 4, the relief image forming apparatus of the present invention is a conventionally known ink jet recording apparatus provided with an appropriate ultraviolet irradiation device similar to that shown in FIG. An example of the relief image forming apparatus of the present invention will be described.

FIG. 4B is a schematic diagram showing an example of the relief image forming apparatus of the present invention. In the figure, 710 is 360d
It is an inkjet recording head with pi and 64 nozzles.
Reference numeral 701 is a recording material. A plurality of recording materials 701 are set in the stocker 711, and the recording material 701 is sent to the belt conveyor by the conveyor 712, and the conveying tray 7 for printing is used.
It is sent to 15. Reference numeral 714 is a feed roller. The recording material 701 sent to the printing transport tray 715 is firmly adsorbed and fixed on the tray by suction by the pump 716. The recording material 701 on the carrying tray 715 is the first
Are sent to the area 702 where the processing steps of 70
4 is a UV / O ₃ lamp. When the surface of the recording material has low wettability, this surface treatment is performed to improve the wettability and adhesion of the ink. This processing step may be passed.

When the recording material is unloaded from the area of the first step by the feed motor 717, the recording head 710 is immediately discharged.
Inkjet recording is performed. For the ink jet recording which is the second step, various ink jet recording methods such as a piezo method and an electrostatic method can be used, but a bubble jet method which can stably perform high speed recording is preferable. Also, as a recording method, if problems such as blurring occur in the case of 1-pass printing, 2 passes or 4 passes
Pass printing is adopted.

The recording material on which the image is recorded is immediately conveyed to the area 703 where the processing of the third step is performed. Here, 705 is a UV irradiation lamp. UV irradiation lamp 7
Since heat may be generated by the irradiation of ultraviolet rays with 05 to deform the recording material, it is preferable to have a heat prevention mechanism such as a cold mirror, a cold filter, and a work air cooling (above, not shown in the figure). .

The recording material (recorded material having a recorded image) that has undergone the above three processing steps is conveyed to the stocker 719 via the belt conveyor 720 and the feed roller 721, and is stored at a predetermined position by the handler 718.
In the illustrated example, the recording material 710 has a plate shape, but the tray 715 that conveys the recording material 710 is appropriately adjusted so as to correspond to the shape of the recording material. For example, by using a spacer 811 or the like as shown in FIG. 6, recording on a disc-shaped recording material can be supported. Further, it is desirable that this apparatus has means for adjusting the distance between the recording head and the image forming surface of the recording material according to the thickness of the recording material.

Further, in order to promote the heating effect in the first step and the third step, a heating means such as a heater is additionally provided on the carrying tray 715 to heat the recording material before each processing. By doing so, it becomes possible to increase the heating efficiency and perform effective processing even for a relatively large recording material having a large heat capacity.

When the heat treatment is performed, thermal expansion causes dimensional deviation, which causes deviations in the recording width direction and the feeding direction, resulting in white stripes in a recorded image and deviations in print size. 7 occurs, the surface temperature of the image forming surface of the recording material 901 is detected by the temperature sensor 9 as shown in FIG.
It is detected by 02 and amplified by an amplifier (Amp), and this is A /
It can be set in the correct position by sending a signal to the recording head 910 and the feed motor 903 with the optimum delay signal for the clock signal after digitizing it with the D converter (A / D) and comparing it with the preset value with the comparator. It is preferable to use a system for adjusting the above.

In order to convey the recording material with high accuracy,
A mark is marked on the non-printed area of the recording material by etching or pressing, the position is read by an appropriate reading means, the position of the recording material is always confirmed, and the conveying means is controlled by that position to improve the accuracy. Higher transportation can also be performed. Further, when the recording material has a warp or the like, it is also effective to add a function of correcting the warp to a roller or the like in order to correct the warp or the like. If the above-mentioned mark impairs the product value, it may be removed by means such as a shearing press after printing.

[0025]

EXAMPLES The present invention will be described in more detail with reference to examples. In the text, "%" is based on weight unless otherwise specified. Example 1 An ink having the composition shown in Table 1 below was prepared according to the process flow shown in FIG. 1, and a relief image was formed on a PET (polyethylene terephthalate) film and an acrylic plate using this ink.

Table 1 * 1; DH-575: 4- (4'-methylphenylthio) -2,5-diethoxybenzenediazonium tetrafluoroborate.

First, 2.2 g of N-methyl-2-pyrrolidone was added to 0.7 g of DH-575, and the mixture was stirred for about 10 minutes (this is referred to as solution A). Next, 20 g of IPA was added to 1 g of polyvinylpyrrolidone, and the mixture was stirred for about 20 minutes to adjust the viscosity to 8 cps (this is referred to as solution B). Solution A: Solution B were mixed at a weight ratio of 1: 7.24 and stirred for 30 minutes to prepare a relief image forming ink. Incidentally, with respect to the above composition, when the amount of polyvinylpyrrolidone was large, the viscosity was high and the ejection characteristics of the ink tended to be deteriorated.

The above ink was printed by an ink jet recording apparatus, and after printing, the printing portion was irradiated with ultraviolet rays. The ultraviolet irradiation intensity at this time was 10 J. At this point, the ink was solidified to the extent that sufficient strength was felt by touching it with the fingertip, and a relief image with sufficient strength was formed. The formation of a relief image by foaming was good, and unevenness due to the touch finger was observed. Also, the adhesion of the relief image to the recording material was good, and it did not peel off even if it was rubbed.

Example 2 An ink having the composition shown in Table 2 below was prepared in the same manner as in Example 1 and a relief image was formed on a PET film and an acrylic plate. Table 2 The formation of a relief image by foaming was good, and unevenness due to the touch finger was observed. Further, the adhesion to the recording material was good, and it did not peel off even if it was rubbed.

Example 3 In Examples 1 and 2, the relief image was formed without adding a coloring material to the ink, and the emphasis was placed on the confirmation of the unevenness by the touch finger. However, the relief image can be visually enjoyed by adding a coloring material to the ink. Therefore, in this example, the case where a coloring material was added to the ink was confirmed. An ink having the composition shown in Table 3 below was prepared according to the flow shown in FIG. 2, and PET was prepared using this ink.
A relief image was formed on the film and the acrylic plate.

Table 3

First, 2.2 g of N-methyl-2-pyrrolidone was added to 0.7 g of DH-575, and the mixture was stirred for about 10 minutes (this is referred to as solution A). Next, 20 g of IPA was added to 1 g of polyvinylpyrrolidone, and the mixture was stirred for about 20 minutes to adjust the viscosity to 8 cps (this will be referred to as solution B).

Solution A: solution B were mixed at a weight ratio of 1: 7.24, 6 g of DBL-199 was further added, and the mixture was stirred for about 30 minutes to prepare a relief image forming ink. With respect to the composition, when the amount of polyvinylpyrrolidone is large, the viscosity is high, and the ejection characteristics of the ink tend to be deteriorated.

An ink of this composition was printed using an ink jet recording device, and after printing, the printed portion was irradiated with ultraviolet rays. The ultraviolet irradiation intensity at this time was 10 J. At this point, the ink was solidified to the extent that sufficient strength was felt by touching it with the fingertip, and a relief image with sufficient strength was formed. With respect to the formation of the relief image and the adhesion to the recording material, the same effects as those of the above Examples 1 and 2 could be obtained.

Example 4 Next, it was confirmed that water was mixed and used. An ink having the composition shown in Table 4 below was prepared according to the flow shown in FIG. 3, and a relief image was formed on a PET film and an acrylic plate using this ink.

Table 4

First, 2.2 g of N-methyl-2-pyrrolidone was added to 0.7 g of DH-575 and stirred for about 10 minutes (this will be referred to as solution A). Next, 16.8 g of IPA is added to 1 g of polyvinylpyrrolidone, and the mixture is stirred for about 20 minutes. Further, add 3.6 g of water and stir for about 20 minutes,
The viscosity was adjusted to 8 cps (this is Solution B). Solution A: Solution B are mixed at a weight ratio of 1: 7.24,
The ink was stirred for 30 minutes to obtain a relief image forming ink.

The ink of this composition was printed by using an ink jet recording apparatus, and after printing, the printing portion was irradiated with ultraviolet rays. The ultraviolet irradiation intensity at this time was 10 J. By adding water to the ink, more vigorous foaming is performed,
An even better relief image was formed. In addition, unevenness due to the fingers was recognized. Adhesion of the relief image to the recording material was good, and the relief image was not peeled off.

[0039]

As described above, according to the present invention, an excellent relief image can be formed on a non-liquid absorbing recording material by the ink jet method. Further, since the ink of the present invention is water-based, it is advantageous for the environment.

[0040]

[Brief description of drawings]

FIG. 1 shows a process flow of Example 1.

FIG. 2 shows a process flow of Example 3.

FIG. 3 shows a process flow of Example 4.

FIG. 4 shows an inkjet recording apparatus using the ink of the present invention.

FIG. 5 is a schematic diagram showing an example of a relief image forming apparatus of the present invention.

FIG. 6 shows a configuration example of a tray used in the relief image forming apparatus of the present invention.

FIG. 7 shows an example of a position correction system according to the temperature of the image forming surface of the recording material when aligning the recording material and the recording head in the relief image forming apparatus of the present invention.

[Explanation of symbols]

1: Ink-jet recording head integrated with ink tank 2: Ink-jet recording device 701: Recording material 702: Area where first step is performed 703: Area where third step is performed 704: UV / O ₃ irradiation lamp 705: UV Irradiation lamp 711, 719: Stocker 712, 718: Handler 713, 720: Belt conveyor 714, 721: Feed roller 715: Conveying tray 716: Suction pump 717, 903: Feed motor 710, 910: Recording head 811: Auxiliary sheet 902: Temperature sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromichi Noguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (13)

[Claims] 1. An inkjet recording ink comprising at least a photosensitive compound which decomposes by ultraviolet rays to generate a gas, a solvent which dissolves the photosensitive compound and a film-forming resin. 2. The ink for ink jet recording according to claim 1, wherein the photosensitive compound is an azo compound. 3. The solvent is a water-soluble organic solvent.
The ink jet recording ink according to item 1. 4. The ink jet recording ink according to claim 1, wherein the solvent contains a water-soluble organic solvent that promotes the generation of gas. 5. The inkjet recording ink according to claim 1, wherein the solvent contains water. 6. The film-forming resin has a softening point of 40 to 85 ° C.
The ink for ink jet recording according to claim 1, which is the water-soluble thermoplastic resin. 7. The ink jet recording ink according to claim 1, further comprising a coloring material. 8. A non-liquid-absorbent recording material is recorded with the ink according to any one of claims 1 to 7 using an inkjet recording device, and after recording, the recorded image is irradiated with ultraviolet rays. Relief image forming method. 9. The relief image forming method according to claim 8, wherein the ink jet recording apparatus has a recording head having a plurality of ink ejection holes. 10. The relief image forming method according to claim 8, wherein the ink jet recording apparatus is of a bubble jet type. 11. A relief image forming apparatus comprising an ink jet recording apparatus having an ultraviolet irradiating device in a paper discharge section. 12. The relief image forming apparatus according to claim 11, wherein the ink jet recording apparatus has a recording head having a plurality of ink ejection holes. 13. The relief image forming apparatus according to claim 11, wherein the ink jet recording apparatus is of a bubble jet type.