JP2001164168A - Offset printing ink and printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink which allows no temporal change in its performance as an offset printing ink, and a printing device which is equipped with a recording and fixing means suited for this ink and stably yields a good printing quality. SOLUTION: After transferring an ink 2 onto a recording medium 1, a contact solid member 11 exerting a swelling property against ink-containing solvents is brought into contact with the ink-transferred surface, preferably while heating, for early curing and fixation of the transferred ink. The ink used here has an iodine value of <=100 and contains an antioxidant and a dry resin and/or a semi-dry resin and/or a non-dry resin having an unsaturated double bond. Here, BHA or BHT is used as the antioxidant, and propyl gallate is used as a synergist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink and a printing apparatus used for so-called offset printing, and more particularly, to an ink used for recording an image of a printing apparatus including a printer and fixing to a recording medium suitable for the ink. The invention relates to a printing device having means.

[0002]

2. Description of the Related Art An ink conventionally used in offset printing is an ink containing a resin and a solvent compatible with the resin, and is commercially available oil-based printing ink (offset ink, waterless lithographic ink, letterpress printing plate). Ink), as well as other inks that do not have an ink curing component such as an oxidative polymerization reaction mechanism, can fix the ink in a short time without lowering the ink density when the ink is transferred to the recording medium. In terms of performance, the properties do not change with time, and a sufficient fixing method could not be obtained.

[0003] In order to solve these problems, a solution to the problem has been sought. After transferring the ink to a recording medium, a solid member which swells with respect to a solvent (ink-containing solvent) contained in the ink is formed on the ink transfer surface. It has been proposed that the ink be fixed in a short time by contact with the ink, and an ink containing a resin and a solvent compatible with the resin in the ink is used as the ink.

As the resin, rosin-modified phenol resin, rosin-modified ester resin, petroleum resin, DCPD resin, alkyd resin and the like are considered to be suitable. The solvent having compatibility with the resin may be any of a polar solvent and a non-polar solvent such as an aliphatic hydrocarbon, an aromatic, a ketone and an alcohol, and is preferably a non-volatile solvent having a high boiling point of 100 ° C. or more. Examples of such inks include commercially available oil-based inks such as offset inks, letterpress inks, waterless lithographic inks, and stencil inks.

Some of these oil-based inks contain an oil for dissolving the resin, a drying oil (unsaturated fatty acid) necessary for oxidative polymerization and drying, and other curing agents. And
Due to the aging of the oil component contained, a thin film is formed on the surface of the ink when placed for a long time.
There is a problem that a phenomenon such as g occurs and impairs the performance of the ink required for use in a printing apparatus.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and is based on oil-based printing inks used in offset printing (offset ink containing oil, waterless lithographic ink, letterpress ink). As an ink that does not change over time in its performance,
It is another object of the present invention to provide a printing apparatus which can stably obtain good printing quality by providing recording and fixing means suitable for using the ink.

[0007]

The invention of claim 1 is characterized by containing a resin having an unsaturated double bond and an antioxidant, and having an iodine value of 100 or less.

According to a second aspect of the present invention, in the first aspect, BHA (butylhydroxyanisole) or BHT (dibutylhydroxytoluene) is used as the antioxidant, and propyl gallate is used as a synergist. It is characterized by doing.

According to a third aspect of the present invention, there is provided an offset printing composition containing a resin having an unsaturated double bond, an antioxidant, and a solvent compatible with the resin, and having an iodine value of 100 or less. A printing apparatus using ink, comprising a solid member that comes into contact with an ink forming a recorded image on a recording medium surface after the transfer of the ink to a recording medium, wherein the solid member contains the ink. And has a swelling property with respect to the solvent.

According to a fourth aspect of the present invention, there is provided the printing apparatus according to the third aspect, wherein the solid member contains a silicone resin.

According to a fifth aspect of the present invention, in the third or fourth aspect, there is provided a solid member heating means for heating the solid member.

According to a sixth aspect of the present invention, in any one of the third to fifth aspects of the present invention, a plurality of the solid members are provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an ink for offset printing and a printing apparatus according to the present invention will be described below with reference to the accompanying drawings. (Invention of Claim 1) Resins having unsaturated double bonds are generally called dry resins, semi-dry resins, and non-dry resins, depending on the iodine value of the resin. The iodine value of the dry resin is about 150 to 180, and the iodine value of the semi-dry resin is 1
The iodine value of the non-drying resin is about 10 to 10
About 0, as the dry resin, for example, linseed oil-modified alkyd resin and the like, as the semi-dry resin, for example, rosin-modified phenol resin, rosin-modified ester resin, and the like, as the non-drying resin, for example, And phenolic resins.

The antioxidant is a substance which oxidizes itself to interrupt the oxidation which is a chain reaction, and includes a phenolic compound, a quinone compound, an amine compound, an organic acid, an alcohol, an ester, and an inorganic compound. There are acids, inorganic salts, sulfur compounds and the like, and the most common one is a phenolic compound.

The present inventor has previously proposed an offset printing ink containing an oil having an iodine value of 100 or less as a vehicle component (Japanese Patent Application No. 10-2131).
No. 87). It was confirmed that the ink has less change with time, such as so-called filming, in which a thin film is formed on the surface of the ink, compared to an ink containing an oil having an iodine value of more than 100. This is presumably because the oil having an iodine value of 100 or less has a feature that the number of double bonds is small and the solidification by reaction with oxygen in the air is extremely unlikely. Therefore, in the invention of claim 1, the iodine value of the ink is set to 100 or less.

According to a first aspect of the present invention, offset printing is carried out by including the above-mentioned dry resin and / or semi-dry resin and / or non-dry resin and the above-mentioned antioxidant, and having an iodine value of 100 or less. For use in printing equipment.

(Examples of the Invention of Claim 1) Examples of inks prepared: Three kinds of inks A, B and C were prepared by using a rosin-modified phenol resin as a semi-dry resin and BHA as an antioxidant in the following table. 1 was prepared.
The numbers in Table 1 indicate% by weight.

[0018]

[Table 1]

Evaluation results: Table 2 below shows the evaluation results of the respective inks shown in Table 1 in comparison with the conventional examples. The conventional offset ink and the ink of the present invention are heated at 60 ° C.
When the conventional offset ink is left for one week, a thin film is formed on the ink surface (so-called filming). On the other hand, the ink of the present invention did not change in appearance, did not feel a change even when stirred with a glass rod, and could not recognize a change with time.

[0020]

[Table 2]

(Invention of claim 2) The invention of claim 2 is a BHA which is excellent in safety according to the standard of cosmetic raw materials and the official standard of food additives among the antioxidants described in the above invention of claim 1. By using (butylhydroxyanisole) or BHT (dibutylhydroxytoluene) and using propyl gallate as a synergist, the ink is used as an ink for offset printing for a printing apparatus.

(Example of the invention according to claim 2) Example of ink produced: BHA or BHT is used as an antioxidant, propyl gallate is used as a synergist, and an antioxidant and a synergist are used for each of the four pigments. By changing the composition of the inks, the total of 24 inks (A to X of the present invention)
Were prepared with the compositions shown in Tables 3 to 6 below. Table 3
And the numbers in Table 6 indicate% by weight. Further, for comparison with the present invention, inks (conventionally A to D) corresponding to the examples of the present invention were prepared with components shown in Tables 7 to 10 below, as components not containing an antioxidant and a synergist. Test.

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5]

[0026]

[Table 6]

[0027]

[Table 7]

[0028]

[Table 8]

[0029]

[Table 9]

[0030]

[Table 10]

Evaluation results: Table 11 below shows the evaluation results of the inks A to X shown in Tables 3 to 6 in comparison with the conventional examples. When the conventional offset ink and the ink of the present invention are left at 60 ° C. for one week, the conventional offset ink forms a thin film on the ink surface (so-called filming). On the other hand, the ink of the present invention did not change in appearance, did not feel a change even when stirred with a glass rod, and could not recognize a change with time.

[0032]

[Table 11]

(Invention of Claim 3) FIGS. 1 to 5 are views for explaining an embodiment of the invention of claim 3, respectively.
In the figure, 1 is a recording medium, 2 is an ink, 3 is a recording layer, 4 is a substrate, 5 is a plate, 10 is an ink fixing unit, 11 is a contact solid member, 12 is a pressure roller, and FIG. 2 is an example of a configuration of printing, FIG. 2 is an example of a configuration of offset printing, FIG. 3 is an example of a configuration of letterpress printing, FIG. 4 is an example of a configuration of stencil printing, and FIG. Is shown. Here, it is assumed that the recording medium 1 is transported in the direction of arrow A.

In this embodiment, as described below, after transferring the ink 2 to the recording medium 1, the contact solid member 11 which swells with respect to the solvent (ink-containing solvent) contained in the ink 2 is transferred to the ink. The fixing of the ink is performed by contacting the transfer surface. The ink used here is an ink containing a resin and a solvent compatible with the resin in the ink. As the resin, rosin-modified phenol resin, rosin-modified ester resin, petroleum resin, DCPD resin, alkyd resin and the like are suitable. The solvent having compatibility with the resin may be any of a polar solvent and a non-polar solvent such as aliphatic hydrocarbons, aromatics, ketones and alcohols, and is preferably a non-volatile solvent having a high boiling point of 100 ° C. or higher. .

The swelling property of the contact solid member 11, which swells with respect to the solvent contained in the ink, is defined as a property that when the solvent contained in the solid member is dropped, the solvent dropping area expands in about one minute or less. Say. As the solid member exhibiting such properties, any of an organic material and an inorganic material may be used, but a resin member is particularly preferable. As the resin, a polymer, a polymer blend, a polymer alloy, a cross-linked product or a vulcanized product thereof is preferable. . In addition, a member having high elasticity such as rubber is desirable because the contact with the recording medium 1 is improved and the ink fixing efficiency is improved. Specifically, silicone resin (polymer and rubber), butyl rubber, chloroprene rubber, natural rubber, candy rubber, olefin elastomer and the like are desirable.

The above-mentioned curing phenomenon of the ink can be explained as follows. The present inventors have confirmed that the solvent content in the ink decreases after the ink is cured. That is,
It is presumed that the curing of the ink is due to the fact that the ink-containing solvent diffuses into the solid member due to the contact with the solid member and the content in the ink decreases. When the ink-containing solvent comes into contact with a solid member showing neither permeability nor swelling, the ink-containing solvent is expected to hardly diffuse into the solid member with which the ink is in contact (contact solid member), and the ink is cured. It is easy to avoid. On the other hand, the contact solid member that shows permeability but does not show swelling with the ink-containing solvent and the contact solid member that shows swelling both diffuse the ink-containing solvent into the contacting solid member at the time of contact with the ink. Can occur. However, the degree of ink curing differs greatly between the two.

The present inventors consider this difference as follows. That is, the contact solid member that shows permeability to the ink-containing solvent but does not show swelling generally has a porous structure in many cases. Therefore, when the ink comes into contact with the contact solid member, it is expected that the ink itself penetrates into the contact solid member to some extent. For this reason, it is considered that the solvent contained in the ink becomes difficult to separate from the ink, and the ink hardly hardens. On the other hand, contact solid members that show swelling with respect to ink-containing solvents often have a dense network of molecular chains,
For this reason, the ink itself hardly diffuses into the contact solid member,
It is believed that the ink hardens because only the ink-containing solvent diffuses into the solid. Further, the swellability of the contact solid member with respect to the ink-containing solvent can be optimized by a solubility parameter (SP value) between the solid and the solvent.
When the ink-containing solvent is known, the ink can be efficiently cured by selecting a contact solid member having a value close to the SP value.

As shown in FIG. 6 to FIG. 8, the contact solid member 11 is applied to a general offset printing machine as it is, that is, it is attached to a conveyance path of a recording medium immediately after transfer. It is preferable to provide the printer without any major design changes. In multicolor printing, when the ink is fixed by the contact solid member 11 between the ink transfer portions C, M, Y, and K as shown in the configuration example of FIG. Since the next color ink can be transferred after the color ink has been cured to some extent, high-speed multicolor printing can be performed without transferring the previous color ink on the recording paper 1 onto the next color plate or blanket. Further, since the ink is fixed for each color, the fixing efficiency is improved. However, when it is difficult to mix with other colors at the time of transfer due to the ink, paper, device configuration, or the like, fixing may be performed by the contact solid member 11 last, as shown in FIG. 9B.

(Example of the invention according to claim 3) Ink composition used: Inks A to X of the invention according to the example of the invention according to claim 2 (see Tables 3 to 6) Contact solid member: for ink-containing solvent As a swellable contact solid member, butyl rubber, chloroprene rubber, natural rubber, candy rubber, olefin-based elastomer, and silicone rubber are used.
m). Evaluation method: Each ink was thinly kneaded with a hand roller made of fluoro rubber (Viton), and the ink was applied on paper by rolling the hand roller on art paper. Thereafter, the art paper was placed on a hot plate, and the contact solid member was brought into contact with the ink surface for a certain period of time while heating. After the contact solid member was peeled off, the ink surface was wiped with a rag to evaluate the fixing of the ink. Evaluation result: As shown in Table 12, the curing time is shortened by heating the art paper regardless of the contact solid member.

[0040]

[Table 12]

(Embodiment 4) This embodiment differs from the embodiment 3 in that the contact solid member 11 is made of silicone resin. The present inventors have conducted various studies on solid members exhibiting swelling properties with respect to an ink-containing solvent, and as a result, have found that among these, silicone resins are particularly excellent. Silicone resin cures the ink quickly among the contacting solid members, and in the case of other contacting solid members, when the contacting solid member is separated from the ink layer before the ink has hardened to some extent, the surface of the solid member becomes solid. While the ink adheres slightly, in the case of the silicone resin, the ink does not adhere to the surface of the silicone resin even if the ink is released while it is soft. That is, in the method of fixing the ink without lowering the ink concentration, it can be said that the silicone resin has the highest reliability as the contact solid member.

Even if the contact solid member of the silicone resin is released from the ink while the ink is soft, the ink does not adhere to the surface of the contact solid member (silicone resin) because of the low surface energy of the silicone resin and the WBFL theory. As shown, it is considered that the extremely thin silicone oil layer is formed on the surface of the silicone resin. There are other members simply having a low surface energy, such as a fluororesin, but the fluororesin has a poor swelling property with respect to an ink-containing solvent, and has no effect on ink curing. That is,
Silicone resin has the unique property of not adhering ink and showing swelling properties with ink-containing solvents. By combining ink-containing solvents with this silicone resin, the reliability of ink fixing is dramatically increased. To improve.

The silicone resin used as the contact solid member may be a crosslinked or vulcanized product such as a chain polymer or branched polymer having a siloxane structure as a unit, or a heat-cured silicone rubber. In addition, dimethyl type and methyl vinyl type,
Any modified silicone resin such as methylphenylvinyl resin may be used. The resin may be a rigid body, an elastic body such as rubber, or a semi-solid such as gel. In addition, an elastic body containing a silicone resin is also excellent. Furthermore, when a crosslinked silicone resin is used, a lower crosslink density is more preferable because of excellent solvent swellability.

(Example of the invention according to claim 4) Ink composition used: Inks A to X of the invention according to the example of the invention according to claim 2 (see Tables 3 to 6). A roller member made of silicone rubber is used as a swellable contact solid member. Evaluation method: Each ink was thinly kneaded with a hand roller made of fluoro rubber (Viton), and the ink was applied on paper by rolling the hand roller on art paper. Thereafter, a silicone rubber roller as a contact solid member was rolled on the art paper at a constant speed, and after the contact solid member was peeled off, the ink surface was wiped with a rag to evaluate the fixing of the ink. Evaluation result: Even if the silicone rubber roller was rolled on the art paper to which the ink was adhered in a state where the ink had not been cured, no ink adhered to the surface of the silicone rubber roller. Also, the ink cured quickly.

(Embodiment 5) In this embodiment, the recording medium surface is heated by heating the recording medium before or at the time of contact with the contact solid member in the embodiment of the above-mentioned invention 3. It cures the ink. Generally, the correlation between compatibility between a resin and a solvent having compatibility with the resin is represented as shown in FIG. That is, even if the resin and the solvent are compatible, the resin and the solvent are phase-separated when the temperature is equal to or higher than the lower critical solution temperature or equal to or lower than the upper critical solution temperature.
For example, in the diagram shown in FIG. 10, when a certain resin ratio (P% in FIG. 10) is determined, the compatible resin solution is heated at the lower critical solution temperature T2c or higher at that time, or
When cooled below the upper critical solution temperature T1c, the resin liquid becomes
Separates into resin and solvent.

The present inventors have found that the ink curing time can be further reduced by combining this property with the above-described curing of the ink by solid contact. Among them, the heating method has an advantage that a generally inexpensive apparatus can be used as compared with the cooling method. Therefore, the ink on the recording medium is heated before or at the time of contact with the contact solid member to further promote the curing of the ink. It is most effective if the heating temperature is higher than the upper critical solution temperature, but it is necessary to increase power consumption for heating. As a result of the study, it has been found that when combined with the contact by a solid member, the ink curing time can be shortened by heating without necessarily heating the solution above the upper critical solution temperature.

This is presumably because the uniformity of the compatibility between the resin and the solvent is easily lost only by heating, and the curing of the ink is promoted by the diffusion of the solvent into the contacting solid member. Although it was considered that the heating accelerates the curing due to the evaporation of the ink-containing solvent, the heating temperature when the present inventors examined the heating temperature was considerably lower than the temperature at which the ink-containing solvent volatilized, It is considered that the contribution of the evaporation of the solvent is low because of the effect of promoting the curing by heating.

As the heating method, as shown in FIG. 11, the simplest configuration is such that the contact solid member 11 is formed on a hollow roller 41 as a support member and is heated from the inside by an infrared heater 42. Further, the present invention can be implemented as shown in FIG. In FIG. 12, reference numeral 40 denotes a heating source. In the illustrated example, the heating source 40 is a heating roller, and has a mechanism capable of detaching from the contact solid member 11. By controlling the degree of desorption of the heating roller 40 according to the amount of the ink-containing solvent in the contact solid member 11, heating is adjusted to remove the ink-containing solvent.

(Example of the invention of claim 5) Ink composition used: Inks A to X of the present invention in the example of the invention of claim 2 (see Tables 3 to 6) Plate: waterless lithographic plate Contact solid member: ink A roller member made of silicone rubber (surface roughness 0.5 μm, rubber hardness 20 degrees, roller diameter φ150 m) as a contact solid member showing swelling property with respect to the contained solvent
Use m). Recording paper: Art paper Contact solid member heating device: As shown in FIG. 11, a hollow silicone rubber roller 11 with a built-in heater (fixing unit 10 of a plain paper copying machine) is used. Heating set temperature is 60
° C. Evaluation method: Monochromatic sheet-fed commercial offset printing press (Ricoh 1
310), and as shown in FIG. 12, a printing machine in which a silicone rubber roller 11 as a contact solid member and a heating roller 40 (heating device) are arranged in a paper discharge portion after ink transfer, and the heating roller 40 After the printing, the contacted solid member (silicone rubber roller 11) was brought into contact, and the rollers (40, 11) were rotated with each other for 5 minutes. Using the above ink, a 1 cm × 1 cm solid image pattern was printed, and the ink surface was wiped with a rag to evaluate the fixing of the ink. Evaluation result: At a printing speed of 40 ppm / A4, by installing this ink fixing unit 10, the ink on the paper after printing was sufficiently fixed. In addition, when heating was not performed, the fixing ability was reduced when printing 1,000 sheets was repeated 50 times.
There was no problem even if it was repeated 0 times.

(Embodiment 6) This embodiment is a printing apparatus in which a plurality of contact solid members 11 are provided in the embodiment of the embodiment 3. FIG. 13 shows a specific example thereof. When using a solid member that has only one contact solid member and ink curing does not occur unless a certain contact time is taken,
In order to sufficiently fix the ink, it is necessary to reduce the speed at which the printed matter after recording passes through the contact member. Therefore, by providing a plurality of contact solid members, the contact time can be equally increased. The present invention can be applied not only to offset printing but also to all printing apparatuses using ink containing a resin and a solvent compatible with the resin, such as letterpress printing, stencil printing, and gravure printing.

(Example of the invention of claim 6) Ink composition used: Inks A to X of the invention in the example of the invention of claim 2 (see Tables 3 to 6) Plate: zinc oxide master Contact solid member: ink A roller member made of silicone rubber (surface roughness: 0.5 μm, rubber hardness: 20 degrees, roller diameter: φ40 m) as a contact solid member showing swelling property to the contained solvent
m). Recording paper: Fine paper Evaluation method: Offset printing press (Ricoh 1)
310), and as shown in FIG. 13, 20 silicone rubber rollers 11 as a contact solid member were arranged at the paper discharge portion after the ink transfer. 1cm using the above ink
A solid image pattern of × 1 cm was printed, and the ink surface was wiped with a rag to evaluate the fixing of the ink. Evaluation result: At a printing speed of 140 ppm / A4, by installing this ink fixing unit 10, the ink on the paper after printing was sufficiently fixed.

[0052]

(1) Advantages of the first and second aspects of the present invention: By providing ink with little deterioration over time, there is no need to clean the inking roller after use for printing, and maintenance work is performed. Has become easier. Further, even after the ink was left, the ink could remain on the inking roller, so that printing could be started immediately and the productivity was improved.

(2) The effect of the third aspect of the invention: In addition to the effects of the first and second aspects of the present invention, by bringing a solid member showing swelling property with respect to a solvent into contact with the ink, the ink can be applied to paper. Since the fixing rate is improved and the set-off is reduced, the reliability of the printing quality is improved, and the time required for the fixing is shortened and the productivity is improved.

(3) Effect of the invention of claim 4: The effect of improving the fixability according to the invention of claim 3 can be achieved in a shorter time. In addition, since a silicone member is used as an adhesive solid member having a swelling property with respect to a solvent, ink does not adhere to the silicone member, so that the amount of ink on the paper surface does not change and the image density is stable. When the silicone member is formed into a roller shape, it can be reused and its diameter can be reduced.

(4) Effect of the fifth aspect of the invention: The effect of improving the fixability according to the third aspect of the invention can be achieved in a shorter time than that of the fourth aspect of the invention, and the reliability of the printing quality is further improved. Get better.

(5) Effects of the invention of claim 6: Reliability is further improved as compared with the inventions of claims 3 to 5.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of an embodiment of a printing apparatus according to a third aspect of the present invention.

FIG. 2 is a diagram illustrating a main configuration of another embodiment of the printing apparatus according to the third aspect of the present invention.

FIG. 3 is a diagram showing a main configuration of another embodiment of the printing apparatus according to the third aspect of the present invention.

FIG. 4 is a diagram showing a main configuration of another embodiment of the printing apparatus according to the third aspect of the present invention.

FIG. 5 is a diagram showing a main configuration of another embodiment of the printing apparatus according to the third aspect of the present invention.

FIG. 6 is a schematic configuration diagram illustrating an example of an embodiment of a printing apparatus in which a fixing unit is incorporated in the printing apparatus.

FIG. 7 is a diagram showing an embodiment according to the present invention in which a fixing unit is applied to multicolor printing.

FIG. 8 is a diagram showing another embodiment according to the present invention in which a fixing unit is applied to multicolor printing.

FIG. 9 is a diagram showing still another two embodiments of the present invention in which a fixing unit is applied to multicolor printing.

FIG. 10 is a diagram showing a correlation between a resin content in an ink and an environmental temperature.

FIG. 11 is a view showing one embodiment of a heating means for heating a contact solid member.

FIG. 12 is a diagram showing a configuration of an embodiment of a printing apparatus according to the invention of claim 5;

FIG. 13 is a diagram showing a configuration of an embodiment of a printing apparatus according to the invention of claim 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording medium, 2 ... Ink, 3 ... Recording layer, 4 ... Substrate, 5
... plate, 10 ... ink fixing unit, 11 ... contact solid member, 12 ... pressure roller, 13 ... guide roller for conveying printed material before fixing, 14 ... guide roller for printed material, 20 ... printing section,
22: printed matter after fixing, 23: recording paper, 24: roll paper, 30: printing device, 40: heating source (heating roller).

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H113 AA03 AA05 BA05 BC09 DA25 DA28 DA33 DA36 DA60 EA19 FA28 4J039 AE02 AE06 AF01 AF07 BC12 BC20 BC29 BE12 BE24 CA07 EA42 EA43 EA44 GA01 GA02

Claims (6)

[Claims] 1. An offset printing ink comprising a resin having an unsaturated double bond and an antioxidant, and having an iodine value of 100 or less. 2. The offset printing ink according to claim 1, wherein BHA (butylhydroxyanisole) or BHT (dibutylhydroxytoluene) is used as the antioxidant, and propyl gallate is used as a synergist. An ink for offset printing characterized by the following. 3. An offset printing ink containing a resin having an unsaturated double bond, an antioxidant, and a solvent compatible with the resin, and having an iodine value of 100 or less. Having a solid member that comes into contact with the ink forming the recorded image on the recording medium surface after the transfer of the ink to the recording medium, wherein the solid member is disposed with respect to the solvent contained in the ink. And a swelling device. 4. The printing apparatus according to claim 3, wherein said solid member contains a silicone resin. 5. The printing apparatus according to claim 3, further comprising a solid member heating unit that heats the solid member. 6. The printing apparatus according to claim 3, further comprising a plurality of said solid members.