JPH05330266A - Printing method and transfer material - Google Patents

Abstract

PURPOSE:To prevent the generation of a flaw due to the excessive drying of ink on a transfer material in a printing method and transfer material of an offset system. CONSTITUTION:A transfer material having a surface layer 1 permeable to the soluble component contained in ink used in printing and a substrate layer 2 impermeable or hardly permeable to said component is used. Especially, the transfer material whose substrate layer 2 constituted of a flexible permeation preventing layer 3 having low stretchability and a substrate stretchable layer 4 is used. Since the absorption of the soluble component into the transfer material from ink is limited only to a surface layer, the excessive drying of the ink is prevented and the generation of a flaw due to transfer inferiority is suppressed. Especially, when the transfer material constituted of surface layer/ low stretchability flexible permeation preventing layer/substrate stretchable layer is used, the effect reducing the strain of a printing image is also simultaneously obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset type printing method for transferring ink from a plate to a printing medium through a transfer medium, and a transfer medium used therefor for transferring ink such as a blanket onto the transfer medium. is there. The use thereof relates to a printing method using a transfer body having a special structure, which is particularly suitable for print manufacturing of printed wiring boards, various electric elements, and the like, and a transfer body used therefor.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for the introduction of a printing method as a manufacturing method which is cheaper and more efficient than the conventional photolithographic method in the manufacture of various electric elements and the like.

In such a field, printing on a hard substrate such as metal or glass is required, and thus a flexible plate is used (screen printing method, rubber letterpress method, etc.).
Alternatively, an offset printing method using a transfer body made of a soft material such as rubber is used.

The latter is particularly advantageous in terms of dimensional accuracy, and the intaglio offset method is often applied as a method having the widest degree of freedom of usable ink.

The most common transfer body used in the offset printing is a raw rubber composition such as styrene rubber, nitrile rubber, urethane rubber or silicone rubber applied to a fabric base material and vulcanized and cured. In the field of precision printing, a mold injection method is also used for the purpose of improving dimensional accuracy (see Japanese Patent Laid-Open No. 3-71894).

Silicone rubber is one of the most excellent materials. The ink adheres well to silicone rubber in the dry state,
When it is wet with a solvent such as a solvent contained in the ink, it has a property of exhibiting peelability to the ink.

By making good use of this property, it is possible to remarkably increase the transfer rate of the ink from the transfer body to the material to be printed, and it is effective in improving the film thickness of the printing ink film and preventing the occurrence of defects.

It is also known that this effect can be further enhanced by adding a non-reactive silicone oil (polymethylsiloxane) to the silicone rubber (Japanese Patent Publication No. 60-
5479).

As a typical structure, as shown in FIG. 3, there is a simple structure in which a surface layer 1 having elasticity and capable of penetrating an ink solvent is mounted on a base layer 5.

[0010]

The ink used for printing generally contains a solvent represented by a low molecular weight compound such as a solvent that evaporates, which lowers the viscosity of the ink and causes flow deformation of the ink during printing. Not only is it easy to perform, but after printing it evaporates and the ink film dries and solidifies, preventing the deformation and set-off of image lines. This evaporation has a better performance in the case of a volatile solvent that is quickly evaporated after printing, but water and the like having a slightly inferior evaporation performance is also within the technical scope of the present invention.

Although the evaporation also occurs on the plate and the transfer body,
Since the transfer body is usually a permeable material such as rubber, this solvent often penetrates into the transfer body to some extent, which also causes the ink film to dry. If the dry state of the ink progresses before the transfer to the printing medium, there is a problem that the ink is dried on the transfer medium and the ink does not transfer to the printing medium.

Further, if the pattern of the image area is non-uniform and does not exist uniformly, the dry state of the ink becomes non-uniform at the time of transfer to the printing medium, causing defects due to transfer failure. There is.

In order to solve this problem, it is one method to use a material which does not allow the solvent to permeate as the transfer member. However, especially in paste-like inks with poor resin content that are often used for printing precision electronic components,
There is also a problem that a transfer material that is not well compatible with a solvent has poor transferability, and thus it is not always a universal solution. Further, in particular, in order to utilize the releasability due to wetting such as silicone rubber, it can be said that the permeability of the solvent into the transfer body is essential.

The above problem is that when the size of the image lines is extremely different depending on the place, or when there are a dense pattern and an isolated image line, a small image line or an isolated image line is formed on the transfer body. It is likely to appear as a phenomenon of being dropped without being transferred to the printing medium due to overdrying.

In particular, it has been known that alignment marks for registering are apt to be dropped because they are present apart from the effective area, and the following method has been devised as a countermeasure.

(1) In the intaglio offset method, the plate depth of the alignment mark portion is set deeper than the effective area,
A method to delay the drying by increasing the amount of ink in the alignment mark area. (See JP-A-3-61574)

(2) A method in which a dummy pattern is provided around the alignment mark portion so that the dry state thereof approaches the dry state of the effective area. (See JP-A-3-61902)

Although the above-mentioned two methods are sufficiently effective as such, the applicable range is extremely limited.

That is, the above method (1) cannot be applied to the relief printing method or the planographic printing method, which takes time and labor to manufacture the printing plate. It is obvious that the above method (2) cannot be applied to the effective area.

The present invention has been made in view of the above-mentioned problems in the offset type printing method.
It is an object of the present invention to provide a means for preventing the occurrence of defects caused by unevenness of the dried state of ink on a transfer body, without particularly limiting the structure of a plate or the arrangement of image patterns.

[0021]

A printing method according to the present invention is a printing method of an offset method, in which at least a surface layer permeable to a solvent contained in an ink used for printing and an underlayer difficult to penetrate or difficult to penetrate. The purpose is to use a transfer body having the same.

The transfer member used in the printing method of the present invention has at least a surface layer through which the solvent contained in the ink can permeate, and an underlayer that is impervious or difficult to penetrate.
For the convenience of handling, a base layer made of metal, cloth, resin or the like may be provided on the back surface of the base layer, and the base layer may also serve as (or include) the base layer.

It is sufficient for the transfer member to have elasticity as a whole, and even if only some of the layers have elasticity and other layers do not have elasticity, the transfer material has the property of having elasticity. If so, the internal structure does not matter.

The content of the elasticity does not matter as to its internal structure, material, etc. as long as it has elasticity and softness such as elasticity. It is sufficient for the transfer body of the present invention if it exhibits the behavior of elasticity during transfer. Therefore, not only a material whose material itself expands and contracts like rubber alone, but also a material whose structure mechanically expands and contracts like foam resin, for example.

The solvent permeability of the surface layer and the underlayer is appropriately selected depending on the type of plate, ink, substrate to be printed, printing conditions and the like, and the range is not particularly limited.

In general, the permeability of a solvent into a substance is determined by the permeation rate represented by the product of the saturated absorption rate of the substance in the solvent contained in the ink and the diffusion coefficient. Materials having different absorptance and / or diffusion coefficient may be selected.

In this case, it is preferable to use a combination of materials having different permeation rates at least twice, and it is preferable that the difference in permeation rate is large. Therefore, the thickness of the surface layer should be appropriately designed according to the saturated absorption rate and diffusion coefficient of the material of the surface layer with respect to the solvent, the permissible range of the dry state of the ink at the time of transfer to the printing medium, and the like.

As a method of making the solvent permeability of the surface layer different from that of the underlayer, it is most preferable to use different materials, but a method of making the surface layer a porous layer to the extent that the solvent can sufficiently penetrate is also applicable. Is. However, in that case, if the surface roughness is large, it causes disturbance of the edge of the drawing line,
The so-called anchoring effect lowers the transferability to the printing medium, so it is preferable to provide it so that the pores do not open on the surface.

Further, if the pore size is too large compared to the drawing line size, unevenness of the ink dry state occurs in the drawing line and causes transfer failure. Therefore, the pore size is sufficiently smaller than the drawing line size. It is preferable that the pore diameter be 1 μm or less, for example, if the image size is 100 μm.

As described above, the underlayer needs to have a lower permeation rate with respect to the solvent than the material of the surface layer.

The base layer may be a rubber simple substance having a low permeation rate into a solvent, a foamed resin, a metal material, or the like, but the permeation-preventing layer having a permeation-preventing function immediately below the surface layer may be used as the underlying material. ..

It is sufficient for the underlayer to be made of a material that is impermeable or difficult for the solvent to penetrate as a whole. For example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide may be used. The thickness is required to be sufficient to fulfill the function of preventing penetration.

The above-mentioned layer structure is a laminated structure, and it is sufficient that the layers are connected with an adhesive force which is at least not so large that a gap does not occur in a normal state.

The printing method according to the second aspect is intended to use a transfer member having a surface layer with a thickness of 100 μm or less.

The thickness of the surface layer should be appropriately designed depending on the saturated absorption rate and diffusion coefficient of the material of the surface layer with respect to the solvent, the permissible range of the dry state of the ink at the time of transfer to the printing medium, and the like. In general, the thickness of the ink layer on the transfer body is often about several μm, so the thickness of the surface layer is 10 μm.
It is preferably 0 μm or less. In particular, when it is desired to suppress the drying of the ink on the transfer body as much as possible, a particular effect is exhibited by making the thickness of the surface layer a thin film having a thickness of several μm or less.

The printing method described in claim 3 is, in the printing method described in claim 1 or 2, intended to use a transfer member whose surface layer is made of a silicone rubber composition.

When the surface layer is composed of the silicone rubber composition in this manner, the ink adheres well in the dry state, but when it is wet with the solvent contained in the ink, it exhibits peelability with respect to the ink. The transfer rate of the ink from the transfer body to the printing material can be remarkably increased, and the stability of the transfer to the printing material is further improved. This effect is further enhanced by adding silicone oil to the silicone rubber.

When the surface layer is composed of a silicone rubber composition, the ink used for printing has at least one alcoholic hydroxyl group and has a boiling point of 120-120.
An ink containing a mixed solvent of one or more kinds selected from aliphatic alcohols at 260 ° C, preferably polyhydric alcohols or derivatives thereof, as a main solvent is particularly preferable.

Specific examples of the above solvent include butyl alcohol, isopentyl alcohol, ethylene glycol,
Propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoacetate, diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Examples thereof include diethylene glycol monoacetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoacetate, methoxymethoxyethanol, butoxyethoxypropanol and the like.

The composition of the pigment or resin component is not particularly limited, but it is preferable to use one having a good affinity for the above solvent.

Specific examples of the resin component include acrylic type, polyester type, epoxy type, phenol type, melamine type,
It is preferable to use an ink containing a resin such as urea.

According to a fourth aspect of the present invention, there is provided a printing method according to the first aspect.
In the printing method described in 2 or 3, it is intended to use a transfer body having a stretchable material as a base layer and having a thickness of 100 μm or more and 600 μm or less.

In some cases, the positional relationship between the surface of the printed material and the transfer body may rise and fall during rolling of the transfer body due to undulations of the surface of the printed material, vibration of the printing machine, and the like.
There is also a method of absorbing the material by vertically expanding or contracting either the printing material or the transfer material. In this case, it suffices if it can be absorbed by the printing material,
In some cases, it may not be possible to select the material to be printed that can be expanded and contracted.

Therefore, when the thickness of the underlayer is approximately 100 μm or more, the compression amount can be made larger than about 10 μm in the case of silicone rubber or the like, though it depends on the material of the layer having elasticity. It does not depend on the flatness of the material to be printed or the accuracy of the printing machine.

Further, if the thickness of the underlayer is excessively thick, the deformation thereof may cause the distortion of the printed image. Although it depends on the material of the layer, it is preferably 600 μm or less.

At this time, the elastic layer may be constituted only by the surface layer, but when the thickness of the surface layer is reduced for the purpose of controlling solvent absorption, the thickness of the surface layer alone is not sufficient. There are cases. In some cases, the surface layer is merely flexible and does not have elasticity.

In this case, it is necessary to form this elastic layer separately from the surface layer or in combination with the surface layer to form an elastic layer. Therefore, the object can be achieved by forming the underlayer or a part thereof as a stretchable layer or a part of the stretchable layer.

According to a fifth aspect of the present invention, there is provided a printing method according to the first aspect.
In the printing method according to 2 or 3, particularly, the underlayer is
It is intended to use a transfer body having at least a permeation preventive layer for preventing permeation of a solvent contained in the ink and a stretchable base layer.

The base permeation preventive layer may be made of any material which does not allow or permeate the solvent from the surface, and may be, for example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide. The thickness is required to be sufficient to fulfill the function of preventing penetration.

The function of the underlayer has a function of preventing penetration of the solvent in the ink and a function of expansion and contraction for imparting printing pressure. It is necessary to divide these two functions into two materials. Is also possible. For that purpose, the underlayer may be divided into two layers, that is, a permeation preventive layer having a solvent permeation preventive function immediately below the surface layer and a base elastic layer underlying the permeation preventive function.

In particular, when printing at a low printing pressure is necessary for the purpose of preventing the ink film from being crushed due to the printing pressure in thick film printing or the like, a material having a low rubber hardness is also required as the material of the transfer body. ..

In this case, even in the case of a rubber that does not easily permeate a solvent, the solvent permeability may increase as the hardness decreases, and the initial purpose may not be achieved with the two-layer structure of the surface layer and the underlayer. Come on. However, in such a case, if the three-layered structure is sandwiched between the permeation preventive layers, the selection range of the material is widened and the original purpose can be easily achieved.

A printing method according to a sixth aspect is the transfer method according to the fifth aspect, wherein the permeation-preventing layer is made of a material having low elasticity and flexibility, and the thickness thereof is 100 μm or less. The purpose is to use.

When the permeation preventive layer is made of a material having low elasticity and flexibility, deformation of the surface layer is suppressed when the transfer member rolls,
This is preferable because it produces the effect of reducing the distortion of the printed image.

As its material, in particular, polyethylene terephthalate (PET), polybutylene terephthalate (P
Polyester resins such as BT), polyethylene naphthalate (PEN), polycarbonate and polyarylates, and polyamide resins such as nylon-6 and nylon-66 have low elasticity (dimensional stability), flexibility and resistance. It is preferable because it is excellent in solvent properties, penetration prevention properties, and the like.

Further, the thickness needs to be thin enough to have the flexibility necessary for imparting printing pressure, and is about 10
It is most preferably 0 μm or less, and most preferably about 10 to 50 μm.

A printing method according to a seventh aspect is the printing method according to the fifth or sixth aspect, wherein the permeation-preventing layer is a transfer body made of a polyester or polyamide synthetic resin film. It is a thing.

The base layer or the permeation-preventing layer may be made of a material that at least the solvent contained in the ink cannot penetrate or is difficult, and may be, for example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide. However, if the permeation preventive layer is made of a material having low elasticity and flexibility, deformation of the surface layer can be suppressed when the transfer body rolls, and distortion of the printed image can be reduced, which is preferable. is there.

As its material, in particular, polyethylene terephthalate (PET), polybutylene terephthalate (P
Polyester resins such as BT), polyethylene naphthalate (PEN), polycarbonate and polyarylates, and polyamide resins such as nylon-6 and nylon-66 have low elasticity (dimensional stability), flexibility and resistance. It is preferable because it is excellent in solvent properties, penetration prevention properties, and the like. The thickness is required to be sufficient to fulfill the function of preventing penetration.

The printing method according to claim 8 is the printing method according to claim 5,
In the printing method described in 6 or 7, it is intended to use a transfer body having a thickness of the stretchable base layer of 100 μm or more and 600 μm or less.

Even when the base layer is divided into two layers, the permeation-preventing layer and the base elastic layer, the thickness of the base elastic layer is the same as that of a single layer. Is preferably 100 μm or more and 600 μm or less.

The printing method according to claim 9 is 5, 6, and 7.
Alternatively, in the printing method described in Item 8, a transfer body having a lower elastic layer having a hardness lower than that of the surface layer is used.

Here, the hardness of the underlying elastic layer is a problem with the hardness of the surface layer, and comparison of the hardness with other layers is not discussed. For example, if the hardness of the surface layer is 30 to 40 degrees with a JIS-A type hardness meter, the hardness of the underlying elastic layer is preferably in the range of 10 to 20 degrees.

The printing method according to claim 10 is the printing method according to claim 1.
In the printing method described in any one of (1) to (9), a transfer body having a non-stretchable base layer below the underlayer is used.

The base layer is not limited to a material as long as it has an effect of preventing fracture of the support layer such as metals such as iron and stainless steel, and resins. Also, the thickness is not limited as long as it has a rupture prevention effect, but if it is too thick, it will be difficult to handle when mounting. Further, the underlayer and the base layer may be firmly adhered to each other, but any lamination means such as temporary adhesion may be used.

The transfer member according to claim 11 is a transfer member having at least a surface layer into which a solvent contained in an ink used for printing used in a printing method of an offset method can penetrate, and an underlayer which cannot penetrate or is difficult to penetrate. The purpose is the body.

The transfer member used in the printing method of the present invention has at least a surface layer into which the solvent contained in the ink can permeate, and an underlayer which cannot or does not permeate.
For the convenience of handling, a base layer made of metal, cloth, resin or the like may be provided on the back surface of the base layer, and the base layer may also serve as (or include) the base layer.

It is sufficient that the transfer body has elasticity as a whole, and even if only a part of the layers exhibits elasticity and the other layers do not have elasticity, the transfer body has the property of having elasticity. If so, the internal structure does not matter.

As for the content of stretchability, it is sufficient for the transfer material of the present invention if it exhibits a behavior as stretchability at the time of transfer, and if it has stretchable properties such as elasticity and softness, its internal structure. The material does not matter. Therefore, not only a material whose material itself expands and contracts like rubber alone, but also a material whose structure mechanically expands and contracts like foam resin, for example.

The solvent permeability of the surface layer and the undercoat layer may or may not apply to this claim depending on the type of plate, ink, substrate to be printed, printing conditions and the like. This is because the solvent permeability is not defined unless the type of solvent is specified.

However, it is possible to define a solvent-permeable transfer member as long as the solvent of the ink is permeated in the actual use stage, and the ink prepared is also prepared during the stage of preparation for printing. If the solvent is specified, whether or not the claim is infringed can be determined.

The permeability of the solvent into the substance, which is the criterion for the judgment at this time, is determined by the permeation rate represented by the product of the saturated absorption rate and the diffusion coefficient of the substance with respect to the solvent contained in the ink. As the surface layer and the base layer, materials having different saturated absorption rates and / or diffusion coefficients may be selected.

In this case, it is preferable to use a combination of materials having different permeation rates at least twice, and it is preferable that the difference in permeation rate is large.

Therefore, the thickness of the surface layer should be appropriately designed according to the saturated absorption rate and diffusion coefficient of the material of the surface layer with respect to the solvent, the permissible range of the dry state of the ink at the time of transfer to the printing medium, and the like.

As a method of making the solvent permeability of the surface layer different from that of the underlayer, it is most preferable to use different materials, but a method of making the surface layer a porous layer to the extent that the solvent can sufficiently penetrate is also applicable. Is. However, in that case, regardless of whether the surface layer is porous or not, whether or not the surface layer has solvent permeability is a problem in relation to the present claim.

For example, also in the case of the structure of Japanese Utility Model Laid-Open No. 63-49967, the actual degree of permeation into the porous material and the degree of permeation of the oil-resistant rubber layer below it are the criteria for judgment. ..

In that case, if the surface roughness is large, the edges of the image lines are disturbed, and the transferability to the printing medium is lowered due to the so-called anchoring effect. It is preferable to provide it so that it is not opened.

Further, if the pore diameter is too large compared with the drawing line size, unevenness in the dried state of the ink in the drawing line causes transfer failure, so the pore size is sufficiently smaller than the drawing line size. It is preferable that the pore diameter be 1 μm or less, for example, if the image size is 100 μm.

As described above, the underlayer needs to have a lower permeation rate with respect to the solvent than the material of the surface layer. If the permeation rate of the surface layer is statistically significant, this should be taken into consideration in the selection of the thickness and material of the surface layer as described above.

The base layer may be a simple rubber having low penetration into a solvent, a foamed resin, a metal material, or the like, but if a penetration preventing layer having a penetration preventing function is provided immediately below the surface layer, the material thereunder is not limited. Absent.

The underlayer may be made of any material that is impenetrable or difficult to penetrate into the solvent as a whole, and may be, for example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide. The thickness is required to be sufficient to fulfill the function of preventing penetration.

The above layer structure is a laminated structure, and it is sufficient that the layers are connected with an adhesive force that is at least such that a gap does not occur in a normal state.

The transfer body according to the twelfth aspect is intended to be a transfer body having a surface layer having a thickness of 100 μm or less.

The thickness of the surface layer should be appropriately designed depending on the saturated absorption rate and diffusion coefficient of the material of the surface layer with respect to the solvent, the permissible range of the dry state of the ink at the time of transfer to the printing medium, and the like. In general, the thickness of the ink layer on the transfer body is often about several μm, so the thickness of the surface layer is 10 μm.
It is preferably 0 μm or less. In particular, when it is desired to suppress the drying of the ink on the transfer body as much as possible, a particular effect can be obtained by making the surface layer a thin film having a thickness of several μm or less.

The transfer member according to claim 13 is the transfer member according to claim 11.
Alternatively, the transfer body according to item 12 is intended to have a surface layer made of a silicone rubber composition.

When the surface layer is composed of the silicone rubber composition as described above, the ink adheres well in the dry state, but when the surface layer is wet with the solvent contained in the ink, it exhibits peelability to the ink. The transfer rate of the ink from the transfer body to the printing material can be remarkably increased, and the stability of the transfer to the printing material is further improved. This effect is further enhanced by adding silicone oil to the silicone rubber.

When the surface layer is composed of a silicone rubber composition, the ink used for printing has at least one alcoholic hydroxyl group and has a boiling point of 120-120.
An ink containing a mixed solvent of one or more kinds selected from aliphatic alcohols at 260 ° C, preferably polyhydric alcohols or derivatives thereof, as a main solvent is particularly preferable.

Specific examples of the above solvent include butyl alcohol, isopentyl alcohol, ethylene glycol,
Propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoacetate, diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Examples thereof include diethylene glycol monoacetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoacetate, methoxymethoxyethanol, butoxyethoxypropanol and the like.

The composition of the pigment or resin component is not particularly limited, but it is preferable to use one having a good affinity for the above solvent.

Specific examples of the resin component include acrylic type, polyester type, epoxy type, phenol type, melamine type,
It is preferable to use an ink containing a resin such as urea.

The transfer member according to claim 14 is the transfer member according to claim 1.
In the transfer body according to 1, 12, or 13, particularly, the underlayer is made of a stretchable material such as rubber and has a thickness of 100.
It is intended to mean a transfer member having a size of not less than μm and not more than 600 μm.

The positional relationship between the surface of the material to be printed and the transfer body may rise or fall during rolling of the transfer body due to undulations on the surface of the material to be printed, vibration of the printing machine, or the like.
There is also a method of absorbing the material by vertically expanding or contracting either the printing material or the transfer material. In this case, it suffices if it can be absorbed by the printing material,
In some cases, it may not be possible to select the material to be printed that can be expanded and contracted.

In view of the above circumstances, when the thickness of the elastic layer is approximately 100 μm or more, the amount of compression is sufficient in the case of silicon rubber or the like, although it depends on the material of the elastic layer. It can be made larger than about several μm, and is not affected by the flatness of the printed material or the accuracy of the printing machine.

If the thickness of the elastic layer is excessively large, the deformation may cause distortion of the printed image. Therefore, it is preferable that the layer is thin as long as printing pressure is not affected. Although it depends on the material of the layer having the property, it is preferably about 600 μm or less.

However, it suffices if this elastic layer can be constituted only by the surface layer, but when the surface layer is made thin for the purpose of controlling solvent absorption, the thickness of the surface layer is not sufficient. There are cases. In some cases, the surface layer is merely flexible and does not have elasticity.

In this case, it is necessary to form a layer having elasticity in addition to the surface layer or in combination with the surface layer. Therefore,
The purpose can be achieved by forming the underlayer or a part thereof as a stretchable layer or a part of the stretchable layer.

The transfer member according to claim 15 is the transfer member according to claim 1.
In the transfer member according to 1, 12, or 13, particularly, the underlayer includes at least a penetration preventing layer for preventing penetration of a solvent contained in the ink, and an underlayer elastic layer made of a stretchable material such as rubber. The purpose is to use a transfer body having the same.

The base permeation preventive layer may be made of any material that does not allow the solvent from the surface to permeate or is difficult. For example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide may be used. The thickness is required to be sufficient to fulfill the function of preventing penetration.

The function of this underlayer has a function of preventing penetration of the solvent in the ink and a function of expansion and contraction for imparting printing pressure. It is necessary to divide these two functions into two kinds of materials. Is also possible.

For this purpose, the underlayer may be divided into two layers, a permeation-preventing layer having a solvent permeation-preventing function immediately below the surface layer and an underlayer elastic layer having a stretching function thereunder.

Particularly when printing with a low printing pressure is necessary for the purpose of preventing the ink film from being crushed due to the printing pressure in thick film printing or the like, a material having a low rubber hardness is also required as the material of the transfer body. ..

In this case, even in the case of a rubber that is difficult to penetrate the solvent, the solvent permeability increases as the hardness decreases, and the initial purpose may not be achieved with the two-layer structure of the surface layer and the underlayer. come. However, in such a case, if the three-layered structure is sandwiched between the permeation preventive layers, the selection range of the material is widened and the original purpose can be easily achieved.

The transfer member according to claim 16 is the transfer member according to claim 15.
In the transfer body described in (1) above, it is intended to use a transfer body in which the permeation preventive layer is made of a material having low elasticity and flexibility and the thickness thereof is 100 μm or less.

When the permeation preventive layer is made of a material having low elasticity and flexibility, deformation of the surface layer is suppressed when the transfer member rolls,
This is preferable because it produces the effect of reducing the distortion of the printed image.

As its material, in particular, polyethylene terephthalate (PET), polybutylene terephthalate (P
Polyester resins such as BT), polyethylene naphthalate (PEN), polycarbonate and polyarylates, and polyamide resins such as nylon-6 and nylon-66 have low elasticity (dimensional stability), flexibility and resistance. It is preferable because it is excellent in solvent properties, penetration prevention properties, and the like.

Further, it is necessary to be thin enough to have the flexibility necessary for imparting printing pressure, and the thickness is generally 100 μm or less, and most preferably about 10 to 50 μm.

The transfer member method according to claim 17 is the method according to claim 1.
The transfer member described in 5 or 16 is intended to use a transfer member in which the permeation preventive layer is made of a polyester-based or polyamide-based synthetic resin film.

The base layer or the permeation preventive layer may be made of any material that at least the solvent contained in the ink cannot permeate or is difficult, and may be, for example, a metal foil or a vapor deposition film of an inorganic substance such as silicon oxide.

However, if the permeation preventive layer is made of a material having low elasticity and flexibility, the deformation of the surface layer during rolling of the transfer member can be suppressed, and the distortion of the printed image can be reduced. It is preferable because it occurs.

As its material, in particular, polyethylene terephthalate (PET), polybutylene terephthalate (P
Polyester resins such as BT), polyethylene naphthalate (PEN), polycarbonate and polyarylates and polyamide resins such as nylon-6 and nylon-66 have low elasticity (dimensional stability), flexibility and resistance. It is preferable because it is excellent in solvent properties, penetration prevention properties, and the like. The thickness is required to be sufficient to fulfill the penetration preventing function.

The transfer member according to claim 18 is the transfer member according to claim 1.
In the transfer body described in 5, 16, or 17, it is intended to use a transfer body having a thickness of the stretchable base layer of 100 μm or more and 600 μm or less.

Even when the underlayer is composed of two layers, the permeation preventive layer and the underlayer stretchable layer, the thickness of the underlayer stretchable layer is the same as that of a single layer. Is preferably 100 μm or more and 600 μm or less.

The transfer member according to claim 19 is the transfer member according to claim 1.
In the transfer member described in 5, 16, 17 or 18, it is intended that the hardness of the underlying elastic layer is lower than that of the surface layer.

Here, the hardness of the underlying elastic layer is a problem with the hardness of the surface layer, and comparison of the hardness with other layers is not discussed. For example, if the hardness of the surface layer is 30 to 40 degrees with a JIS-A type hardness meter, the hardness of the underlying elastic layer is preferably in the range of 10 to 20 degrees.

The transfer member according to claim 20 is the transfer member according to claim 11.
The transfer member according to any one of items 1 to 19 is characterized in that a non-stretchable substrate layer is provided below the underlayer.

The base layer is not limited to a material as long as it has an effect of preventing fracture such as metals such as iron and stainless steel and resin as a support layer.

Further, the thickness is not limited as long as it has the effect of preventing breakage, but if it is too thick, the handling at the time of mounting becomes difficult.

Further, the underlayer and the base layer may be firmly adhered to each other, but any lamination means such as temporary adhesion may be used.

[0119]

According to the printing method of the present invention, as a transfer member in the offset printing method, at least a surface layer into which the solvent contained in the ink used for printing can permeate and an underlayer which is impervious or difficult to penetrate. By using the transfer body, the solvent permeation from the ink to the transfer body that occurs during the transfer of the ink transferred from the plate to the transfer body surface to the surface of the printing medium is the interface between the surface layer and the underlayer. Will stop at.

Therefore, since the transfer body does not excessively absorb the solvent from the ink and the ink does not excessively dry on the transfer body, even a small image line or an isolated image line can be stably printed. Can be transferred to.

According to the printing method of the second aspect, since the thickness of the surface layer is made extremely thin to 100 μm or less, the permeation of the solvent from the ink into the transfer body can be suppressed to a necessary minimum. Ink drying on the body can be suppressed. When the ink dries, it becomes difficult to transfer it to the printing medium. In the present claim where such a thing is eliminated, the above-mentioned improvement in the stability of transfer to the printing medium is particularly remarkable.

According to the printing method of the third aspect, by using a transfer body whose surface layer is made of a silicone rubber composition having an excellent ink peeling property, transfer from the transfer body to the printing medium is promoted. .. As a result, the ink residue at the time of transfer is reduced, and the stability of transfer to the printing medium is further improved.

According to the printing method of the fourth aspect, the underlayer is made of a stretchable material such as rubber and has a thickness of 100.
By using a transfer member having a thickness of 100 μm or more and 600 μm or less, a stable printing pressure can be applied to the plate and the printing medium because the thickness is 100 μm or more.

Therefore, since the expansion and contraction performance can absorb fluctuations within the contact precision during transfer, and prevent non-contact and over-contact, the transfer stability to the printing medium is excellent, and the thickness is 600 μm. Due to the following, it is possible to minimize the distortion of the printed image due to the deformation of the transfer body during rolling.

According to the printing method of claim 5, the undercoat layer comprises a penetration preventing layer for preventing penetration of the solvent contained in the ink, and a stretchable undercoat layer made of a stretchable material such as rubber. It is composed of at least two layers, and by differentiating the functions of solvent penetration prevention and expansion / contraction for printing pressure,
The material selection range is expanded, and it is possible to apply the present invention in more cases than in the case of being constituted by a single layer.

According to the printing method of claim 6, the permeation-preventing layer is a low-stretch layer having a thickness of 100 μm or less, and at the same time is made of a flexible material. It has become possible to prevent elongation. As a result,
The ink on the surface layer of the transfer body was formed on the printing medium by the deformation according to the deformation of the surface layer of the transfer body without causing any trouble in the application of stable printing pressure. The distortion of the printed image can be reduced.

According to the printing method of claim 7, as a material of the permeation-preventing layer, a polyester resin having excellent low stretchability, flexibility, solvent resistance, permeation resistance and the like, especially among synthetic resin films. Alternatively, by using a polyamide-based synthetic resin film, the effects such as the above-described stability of transfer to a printing medium and reduction of distortion of a printed image become excellent.

According to the printing method of claim 8, by specifying the thickness of the base stretchable layer to be 100 μm or more and 600 μm or less, the same operation as in the case of the printing method of claim 4 is performed. Further, it is possible to further improve the stability of transfer to the printing medium and at the same time reduce the distortion of the printed image.

According to the printing method of the ninth aspect, by prescribing the relationship between the hardness of the underlayer elastic layer and the surface layer, the deformation imparted at the time of printing is mainly taken over by the underlayer elastic layer. Since the load on the surface layer is reduced,
At the same time as the durability was improved, the reproducibility to the distortion of the printed image was improved by suppressing the deformation of the surface layer.

According to the printing method of the tenth aspect, by providing the base layer, no matter how thin each of the other layers is,
This tension can be received by the base layer, and the resistance to this tension can be improved, so that breakage can be prevented. Further, since it is not easily broken, the handling property at the time of mounting is improved, the productivity is increased, and the deterioration due to the deformation of each layer is prevented.

The transfer body according to claim 11 is a transfer body having at least a surface layer through which a solvent contained in an ink used for printing can permeate, and an underlayer that is impervious or difficult to permeate. The permeation of the solvent from the ink into the transfer body, which occurs until the ink transferred from the top to the surface of the transfer body is transferred to the surface of the printing medium, stops at the interface between the surface layer and the base layer, and the transfer body becomes excessive from the ink. Since the solvent does not absorb and the ink does not excessively dry on the transfer body, even a small image line or an isolated image line can be stably transferred to the printing medium.

In the transfer body according to the twelfth aspect, by making the thickness of the surface layer very thin, 100 μm or less, the penetration of the solvent from the ink into the transfer body can be suppressed to the necessary minimum. It is possible to suppress the drying of the ink. When the ink dries, it becomes difficult to transfer it to the printing medium. In the present claim where such a thing is eliminated, the above-mentioned improvement in the stability of transfer to the printing medium is particularly remarkable.

In the transfer body according to the thirteenth aspect, by using the transfer body whose surface layer is made of a silicone rubber composition having an excellent ink peeling property, transfer from the transfer body to the printing medium is promoted. As a result, the ink residue at the time of transfer is reduced, and the stability of transfer to the printing medium is further improved.

According to a fourteenth aspect of the present invention, the underlayer is made of a stretchable material such as rubber and has a thickness of 100 μm.
By using a transfer body having a size of 600 μm or less,
Since the thickness is 100 μm or more, stable printing pressure can be applied to the plate and the printing medium.

Therefore, the variation within the contact precision at the time of transfer can be absorbed by this expansion and contraction performance, and non-contact and over-contact can be prevented, so that the transfer stability to the material to be printed is excellent and the thickness is 600 μm Due to the following, it is possible to minimize the distortion of the printed image due to the deformation of the transfer body during rolling.

In the transfer member according to the fifteenth aspect, the undercoat layer comprises a penetration prevention layer for preventing the penetration of the solvent contained in the ink, and a stretchable undercoat layer made of a stretchable material such as rubber. It is composed of at least two layers, and the functional selection of solvent penetration and expansion and contraction for imparting printing pressure expands the selection range of materials, and it is applied in more cases than in the case of a single layer. You will be able to do it.

According to the sixteenth aspect of the present invention, the permeation-preventing layer is a low-stretch layer having a thickness of 100 μm or less, and at the same time is made of a flexible material, so that the lateral extension of the transfer body can be achieved. It has become possible to prevent.

As a result, the ink on the surface layer of the transfer body is deformed without causing any trouble in giving a stable printing pressure, and is deformed according to the deformation of the surface layer of the transfer body during rolling. The distortion of the printed image formed on the printing medium can be reduced.

In the transfer member according to claim 17, as the material of the permeation-preventing layer, a polyester-based or polyamide-based one excellent in low stretchability, flexibility, solvent resistance, and permeation-preventing property, among other synthetic resin films, is used. By using the synthetic resin film, the effects such as the above-mentioned stability of transfer to the printing medium and reduction of distortion of the printed image become excellent.

In the transfer body according to the eighteenth aspect, by specifying the thickness of the base stretchable layer to be 100 μm or more and 600 μm or less, the same effect as that of the transfer body according to the fourteenth aspect can be obtained. It is possible to improve the stability of transfer to the printed material and reduce the distortion of the printed image.

In the transfer member according to the nineteenth aspect, by defining the relationship between the hardness of the base elastic layer and the surface layer, the deformation imparted at the time of printing is mainly taken over by the base elastic layer, and the surface Since the load on the layers is reduced, the durability is improved and at the same time, the reproducibility of the printed image to distortion is improved.

According to the twentieth aspect of the present invention, by providing the substrate layer, the tension can be applied to the substrate layer regardless of how thin each of the other layers is, and the tensile strength can be improved, so that the breakage occurs. Can be prevented.

Further, since it is not easily broken, the handling property at the time of mounting is improved, the productivity is improved, and the deterioration due to the deformation of each layer is prevented.

[0144]

EXAMPLES Various examples of the present invention and comparative examples will be described in detail below. The surface layer is a silicone rubber layer with a rubber hardness of 40 degrees 25μ
A transfer body having a four-layer structure was prepared in which the permeation-preventing layer was 25 μm in PET film, the stretchable base layer was 450 μm in urethane rubber layer having a rubber hardness of 15 degrees, and the base layer was 350 μm in PET film.

A transfer member having a two-layer structure was prepared in which the surface layer was a silicone rubber layer having a rubber hardness of 40 degrees 500 μm and the substrate layer was a PET film 350 μm.

The surface layer is a silicone rubber layer having a rubber hardness of 40 degrees 25 μm, and the permeation preventive layer is a PET film 300 μm.
Urethane rubber layer with a rubber hardness of 15 degrees
25 μm, PET film 350 μm as base layer 4
A transfer body having a layer structure was prepared.

The surface layer is a silicone rubber layer having a rubber hardness of 40 degrees 25 μm, the permeation preventive layer is a PET film 25 μm,
Urethane rubber layer 450 with rubber hardness of 50 degrees
A transfer body having a four-layer structure with a substrate layer of PET film of 350 μm was prepared.

The surface layer is a silicone rubber layer having a rubber hardness of 40 degrees 25 μm, the permeation preventive layer is an aluminum foil 25 μm,
Urethane rubber layer 450 with a rubber hardness of 15 degrees
A transfer body having a four-layer structure with a substrate layer of PET film of 350 μm was prepared.

The surface layer is a silicone rubber layer having a rubber hardness of 40 degrees 25 μm, and the permeation preventive layer is a polyethylene film 25.
A transfer member having a four-layer structure was prepared in which the base elastic layer was 450 μm in urethane rubber layer having a rubber hardness of 15 degrees, and the base layer was PET film 350 μm.

The surface layer is a silicone rubber layer having a rubber hardness of 40 degrees 25 μm, and the permeation preventive layer is a nylon film 25 μm.
Urethane rubber layer 4 with a hardness of 15 degrees
50 μm, PET film 350 μm as base layer 4
A transfer body having a layer structure was prepared.

Printing was performed under the same conditions using an ink containing 20 parts by weight of carbon black, 40 parts by weight of epoxy resin (# 1007), and 40 parts by weight of diethylene glycol monoethyl ether, using these.

As a result, the loss of fine image lines was remarkable, and the defect was conspicuous due to the unstable printing pressure, but the other good prints could be obtained. However, as printing continues, is likely to cause the deterioration of the drawing shape due to the surface roughness of the silicone rubber layer, wrinkles and cracks may occur in the aluminum foil, and the drawing may be disturbed. Although the deterioration of the dimensional accuracy was observed, no such inconvenience occurred in and.

[0153]

As described in detail above, according to the printing method of the present invention, it is possible to print a fine image pattern with good stability, and the occurrence of defects due to defective transfer is reduced.

When the surface layer has a thickness of 100 μm or less, the transfer stability is remarkably improved and pattern defects are reduced.

When the surface layer is made of a silicone rubber composition as in claim 3 or 13, the transfer stability is remarkably improved and the pattern defects are reduced.

When the underlayer has a thickness of 100 μm or more and 600 μm or less, the transfer stability is remarkably improved and the pattern defects are reduced.

When a transfer body having a laminated structure of a surface layer, a permeation preventive layer, and a base stretchable layer is used in this order as in claim 5 or 15, the range of selection of materials is widened, so that the range of application of the printing method of the present invention is increased. Spreads.

When the transfer member having the penetration preventing layer made of a material having low elasticity and flexibility is used as in claim 6 or 16, the effect of reducing the distortion of the printed image can be obtained.

When the transfer member having the penetration preventive layer made of a polyester or polyamide synthetic resin film and having a low elasticity and flexibility is used, the distortion of the printed image can be prevented. Is obtained.

When a transfer member having a thickness of the stretchable underlayer of 100 μm or more and 600 μm or less is used, the transfer stability of the printed image can be improved and the distortion can be reduced. can get.

When a transfer body having a base elastic layer having a hardness lower than that of the surface layer is used, the durability of the transfer body is improved and, at the same time, the distortion of the printed image is reduced. The effect of reduction is obtained.

When a low transfer member having a non-stretchable base layer below the underlayer is used, the durability of the transfer member is improved and at the same time, The effect that it is easy to handle is obtained.

[0163]

[Brief description of drawings]

FIG. 1 is a conceptual cross-sectional view of an example of a transfer body of the present invention.

FIG. 2 is a conceptual sectional view of another embodiment of the transfer body of the present invention.

FIG. 3 is a conceptual cross-sectional view of an example of a conventional transfer body.

[Explanation of symbols]

 1 Surface Layer 2 Underlayer 3 Permeation Prevention Layer 4 Underlayer Elastic Layer 5 Base Layer

Claims (20)

[Claims] 1. An offset type printing method for transferring an ink containing a solvent from a plate to a surface of a printing medium via a stretchable transfer body, wherein the transfer body has a surface permeable to a solvent contained in the ink. A printing method comprising using a transfer body having at least a layer and an underlayer which is impenetrable or difficult to penetrate. 2. The printing method according to claim 1, wherein a transfer body having a thickness of the surface layer of 100 μm or less is used. 3. The printing method according to claim 1, wherein the surface layer is a transfer member made of a silicone rubber composition. 4. The printing method according to claim 1, 2 or 3, wherein the base layer is made of a stretchable material, and a transfer member having a thickness of 100 μm or more and 600 μm or less is used. 5. A transfer member having at least a permeation preventive layer for preventing permeation of a solvent contained in the ink and a base stretchable layer is used as the base layer.
The printing method according to claim 1, 2 or 3. 6. The printing method according to claim 5, wherein the permeation-preventing layer is made of a material having low elasticity and flexibility, and a transfer body having a thickness of 100 μm or less is used. 7. The printing method according to claim 5, wherein the permeation-preventing layer is a transfer member made of a polyester-based or polyamide-based synthetic resin film. 8. The printing method according to claim 5, 6 or 7, wherein a transfer body having a thickness of the base stretchable layer of 100 μm or more and 600 μm or less is used. 9. A transfer body having a hardness of the base elastic layer lower than that of a surface layer is used.
The printing method according to 6, 7, or 8. 10. A transfer body comprising a non-stretchable substrate layer below the underlayer, which is used.
The printing method described above. 11. A transfer material for printing used in an offset type printing method in which an ink containing a solvent is transferred from a plate to a surface of a printing material via a stretchable transfer material, and the solvent contained in the ink can penetrate. Transfer body for printing, which has at least a transparent surface layer and a base layer which cannot penetrate or is difficult to penetrate. 12. The printing transfer member according to claim 11, wherein the thickness of the surface layer is 100 μm or less. 13. The printing transfer member according to claim 11, wherein the surface layer is made of a silicone rubber composition. 14. The printing transfer member according to claim 11, 12 or 13, wherein the underlayer is made of a stretchable material and has a thickness of 100 μm or more and 600 μm or less. 15. The underlayer comprises at least a permeation preventive layer for preventing permeation of a solvent contained in the ink, and an underlayer stretchable layer.
The transfer member for printing according to 1, 12, or 13. 16. The transfer member for printing according to claim 15, wherein the permeation preventive layer is made of a material having low elasticity and flexibility and has a thickness of 100 μm or less. 17. The printing transfer member according to claim 15, wherein the permeation preventive layer is made of a polyester-based or polyamide-based synthetic resin film. 18. The thickness of the stretchable base layer is 100 μm or more and 600 μm or less.
The transfer member for printing according to 5, 16 or 17. 19. The hardness of the underlying stretchable layer is lower than the hardness of the surface layer.
Or the transfer member for printing according to item 18. 20. The transfer member for printing according to claim 11, further comprising a non-stretchable base layer below the underlayer.