JP2018187793A - Printing apparatus and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing apparatus and a printing method capable of uniformly forming a flat solid film on a curved surface with good reproducibility. A printing apparatus including a slit coater and a blanket, wherein the slit coater is arranged so as to provide a predetermined gap between the tip of the slit coater and the surface of the blanket, and is arranged from the tip of the slit coater. Ink is supplied to the surface of the blanket, and in the blanket, the ink supplied from the slit coater forms a film on the surface of the blanket, and at least a part of the ink film is transferred to the printed matter, so that the surface of the blanket is formed. A printing device that elastically deforms according to the surface shape of the object to be printed. [Selection diagram] Fig. 1

Description

  The present invention relates to a printing apparatus and a printing method. In particular, the present invention relates to a printing apparatus and a printing method capable of uniformly forming a so-called “solid film” flat or a wide pattern on a curved surface.

There are various types of printing techniques in the technical field of printing, and a suitable printing technique is selected according to the pattern shape to be formed, ink thickness, and the like.
In recent years, research in the field of printed electronics for producing electronic devices by printing has been actively conducted. In the printed electronics field, there are two known patterns that are difficult to form by printing: ultrafine wiring and a flat solid film.

Various coating techniques such as spray coating, slit coating, blade coating, and spin coating are known as techniques for forming a flat solid film. However, these coating methods, unlike printing, cannot repeatedly form an arbitrary pattern. Therefore, it is extremely difficult to form a desired flat solid film with good reproducibility by the coating technique regardless of the shape of the object to be coated.
On the other hand, among the printing methods, flexo printing, screen printing, and the like can be cited as what can be considered to form a solid film. However, when a solid film is formed by these printing methods, an anilox roll trace is left in the case of flexographic printing, and a screen mesh trace is left on the solid film in the case of screen printing. For this reason, it is very difficult to form a flat solid film by these printing methods.

  In recent years, there is a demand for printing on a substrate having a curved surface. As a technology to meet such a demand, Japanese Patent Application Laid-Open No. 2006-182728 discloses a predetermined thickness on a metal cylinder in offset printing such as gravure offset printing (intaglio offset printing) in which printing is performed via a blanket. A technique using a blanket in which rubber having a surface hardness is provided in a roll shape having a predetermined diameter is disclosed. Japanese Patent Application Laid-Open No. 2006-182729 discloses a technique of using a blanket in which a roll of PDMS (polydimethylsiloxane) rubber having a predetermined thickness is provided on a metal cylinder in offset printing. Yes.

These technologies have high substrate selectivity because they are printed via the blanket, and because the blanket absorbs the solvent of the ink, there is no spreading of the ink, and fine wiring as designed on the printing plate. In addition, by using a predetermined blanket, it is possible to print a fine and high-precision pattern without distortion on a curved surface.
However, in gravure offset printing, a pattern is formed by filling ink in a concave portion of a plate and this is transferred to a blanket for printing. Therefore, when printing a solid film, a large concave portion is provided in the plate. Therefore, it is necessary to uniformly fill a large amount of ink there. This is accompanied by technical difficulties such as an ink filling method and a printing direction dependency peculiar to gravure offset printing. Therefore, it is not easy to print a solid film by gravure offset printing.

JP, 2006-182728, A JP, 2006-182729, A

  An object of the present invention is to provide a printing apparatus and a printing method capable of forming a flat solid film uniformly on a curved surface with good reproducibility.

  In order to form an ink film on the surface of a relatively soft blanket (soft blanket) that can be elastically deformed according to the surface shape of the printing material, the present inventors have used the ink from the tip of the slit coater. It was found that the above-mentioned problem can be solved by supplying the ink and transferring at least a part of the ink film to the substrate.

  That is, the present invention is a printing apparatus including a slit coater and a blanket, and the slit coater is disposed so that a predetermined gap is provided between the tip of the slit coater and the surface of the blanket. Ink is supplied from the leading edge to the surface of the blanket, and the ink supplied from the slit coater forms a film on the surface of the blanket, and at least a part of the ink film is transferred to the printing material. The printing apparatus is characterized in that the surface is elastically deformed according to the surface shape of the substrate.

The surface energy of the blanket surface employed in the apparatus of the present invention is preferably 20 mN / m or more.
The blanket also preferably has at least the surface of the blanket substantially composed of polydimethylsiloxane.
The blanket may have a laminated structure in which an outer layer including the surface of the blanket is provided on the inner layer.
In this case, the blanket preferably has a thickness of the outer layer smaller than that of the inner layer in the diameter direction of the blanket.
In this case, the outer layer preferably has a higher rubber hardness than the inner layer.
Further, in this case, it is preferable that the blanket in this case has the lower surface of the outer layer and the upper surface of the inner layer bonded to each other due to tackiness of at least one of the lower surface of the outer layer and the upper surface of the inner layer.
The viscosity of the ink employed in the apparatus of the present invention is preferably 1 to 150 mPa · s.
The apparatus of the present invention further includes drying means, and the drying means dries at least a part of the ink film formed on the surface of the blanket prior to transferring at least a part of the ink film to the substrate. Can be.
The apparatus of the present invention further includes an intaglio, and the intaglio exfoliates at least a part of the ink film formed on the surface of the blanket before at least a part of the ink film is transferred to the substrate. It can be.

  The present invention also provides a process of supplying ink to the slit coater, supplying ink from the tip of the slit coater to the surface of the blanket while rotating the blanket, and forming a film of ink supplied from the slit coater on the surface of the blanket And a step of transferring at least a part of the ink film to the substrate, a predetermined gap is provided between the tip of the slit coater and the surface of the blanket, and the surface of the blanket is the surface shape of the substrate The printing method is characterized by elastically deforming in accordance with the printing method.

The surface energy of the blanket used in the method of the present invention is preferably 20 mN / m or more.
The blanket also preferably has at least the surface of the blanket substantially composed of polydimethylsiloxane.
The blanket may have a laminated structure in which an outer layer including the surface of the blanket is provided on the inner layer.
In this case, the blanket preferably has a thickness of the outer layer smaller than that of the inner layer in the diameter direction of the blanket.
In this case, the outer layer preferably has a higher rubber hardness than the inner layer.
Further, in this case, it is preferable that the blanket in this case has the lower surface of the outer layer and the upper surface of the inner layer bonded to each other due to tackiness of at least one of the lower surface of the outer layer and the upper surface of the inner layer.
The viscosity of the ink employed in the method of the present invention is preferably 1 to 150 mPa · s.
The method of the present invention may further include a step of drying at least a portion of the ink film formed on the surface of the blanket prior to the step of transferring at least a portion of the ink film to the substrate.
The method of the present invention may further include a step of peeling at least a part of the ink film formed on the surface of the blanket with the intaglio before the step of transferring at least a part of the ink film to the printing material. it can.

  According to the printing apparatus and the printing method of the present invention, a flat solid film that is often required in an optical application or the like for forming an antireflection film, a light shielding film, etc., particularly on a curved surface, is uniform and reproduced. High formation is possible.

It is a cross-sectional schematic diagram of one form of the printing apparatus of this invention. It is a cross-sectional schematic diagram of one form of the blanket which the printing apparatus of the present invention employs. It is a partial cross-section schematic diagram of the other one form of the printing apparatus of this invention. It is a cross-sectional schematic diagram which shows operation | movement of one form of the printing apparatus of this invention.

Hereinafter, modes for carrying out the present invention will be described.
With reference to FIG. 1A, a printing apparatus 1 of the present invention includes a slit coater 2 and a blanket 3.
The slit coater 2 is arranged so that a predetermined gap 6 is provided between the tip 4 of the slit coater 2 and the surface 5 of the blanket 3.
While rotating the blanket 3, the ink 7 is supplied to the surface 5 of the blanket 3 from the tip 4 of the slit coater 2, and the film 8 of the ink 7 supplied from the slit coater 7 is formed on the surface 5 of the blanket 3.
With reference to FIG. 1B, in the printing apparatus of the present invention, at least a part of the ink film 8 is then transferred to the substrate 9. At that time, the surface 5 of the blanket 3 is elastically deformed according to the surface shape of the substrate 9. In FIG. 1B, the blanket 3 is pressed against the substrate 9 at the portion where the blanket 3 contacts the substrate 9, and the surface 5 of the blanket 3 is elastically deformed according to the surface shape of the substrate 9 and an ink film is formed. It shows how 8 disappears.

Referring again to FIG. 1A, the slit coater 2 employed in the printing apparatus 1 of the present invention is capable of applying a coating liquid such as printing ink to a target work from a slit-like discharge port. If so, there is no particular limitation. When the coating liquid is applied by the slit coater, it is usually performed while the discharge port of the slit coater is moved relative to the target work. In the case of the printing apparatus of the present invention, it corresponds to the target work. The ink 7 may be supplied from the tip 4 of the slit coater 2 to the surface 5 of the blanket 3 while rotating the blanket 3 to move the surface 5 relative to the tip 4 of the slit coater 2.
The predetermined gap 6 between the tip 4 of the slit coater 2 and the surface 5 of the blanket 3 causes the ink 7 supplied from the slit coater 2 to form a film 8 on the surface 5 of the blanket 3 due to surface tension. It can be set so that it can. The gap 6 is preferably set according to the size of the discharge port of the slit coater 2, the rotational speed of the blanket 3, the solid content of the ink 7, the film thickness of the film 8 of the ink 7, and the like.

In the printing apparatus of the present invention, since the ink film is formed on the surface of the blanket without bringing the tip of the slit coater into contact with the surface of the blanket, a uniform ink film can be formed on the surface of the blanket. As a result, according to the printing apparatus of the present invention, it is possible to form a flat solid film uniformly and with good reproducibility by transferring the ink film onto the substrate.
In FIG. 1A, the ink 7 is supplied to the surface 5 of the blanket 3 from the tip 4 of the slit coater 2 disposed obliquely upward of the blanket 3. It is good also as arrange | positioning above. For example, when the viscosity of the ink 7 is low or the surface tension of the ink 7 is sufficiently high, the slit coater 2 may be arranged in the lateral direction of the blanket 3.
As a positional relationship between the blanket 3 and the slit coater 2, it is preferable that the slit coater 2 is disposed on a straight line passing through the center of the blanket 3.

The blanket 3 employed in the printing apparatus 1 of the present invention has a structure in which a cylindrical sleeve 11 made of elastomer such as rubber is provided around a cylinder 10 made of metal such as aluminum or SUS. it can.
In the printing apparatus of the present invention, the blanket is one in which the ink supplied from the slit coater forms a film on the surface of the blanket. In particular, in order to form a uniform ink film on the surface of the blanket, the surface energy of the blanket surface, and the relationship between the surface energy of the blanket surface and the surface energy of the ink are important. The difference between the surface energy of the ink and the surface energy of the ink is considered to be preferable in order to form a uniform ink film on the surface of the blanket.
The slit coater employed in the printing apparatus 1 of the present invention is generally made of metal in many cases, but may be made of plastic, glass, quartz or the like. The thickness of the slit can be determined by sandwiching a thin plate called a shim plate between the slits and the thickness of the shim plate. The slit may be formed without spreading the shim plate, and the width of the opening of the slit is not particularly limited as long as ink can be coated on the blanket.

  The surface energy of the surface 5 of the blanket 3 employed in the apparatus 1 of the present invention is preferably 20 mN / m or more, more preferably 22 mN / m or more. In particular, when using a water-based ink as the ink, the difference between the surface energy of the blanket is smaller when the surface energy of the blanket is higher than when using an ink based on an organic solvent, This is preferable for forming a uniform ink film on the surface of the blanket.

Referring to FIG. 1B again, the blanket 3 employed in the printing apparatus 1 of the present invention has a surface 5 that is elastically deformed according to the surface shape of the substrate 9. For example, as the cylindrical sleeve 11 of the blanket 3, a vulcanized rubber such as styrene rubber or butadiene rubber, or a soft one made of elastomer may be used.
In the printing apparatus of the present invention, since the surface of the blanket is elastically deformed according to the surface shape of the substrate, it is possible to follow the surface of the curved surface and form a flat solid film uniformly on the surface with good reproducibility. Become.

As the blanket 3, for example, the surface 5 having an ASKER C hardness of 5 to 40 can be used. However, when the diameter (roll diameter) of the blanket 3 is small, a relatively wide range of surface hardness is allowed, whereas when the roll diameter is large, the surface hardness is preferably high.
The minimum value of the roll diameter of the blanket 3 can be determined by the printing area.

The thickness of the blanket 3 will be described. When printing on a curved surface using a thick and soft blanket, basically, the blanket can be printed if the thickness of the blanket is more than double the unevenness of the surface (printing surface) of the substrate. For example, if the difference in unevenness of the curved surface is 5 mm, the blanket thickness should be 10 mm or more. However, as the unevenness difference is reduced, a blanket thickness that is twice the unevenness difference of the curved surface is not sufficient, and a blanket thickness exceeding this is required. Here, if the “curved surface” is a surface having a radius of curvature of 0.5 mm or more and an unevenness difference of 0.5 mm or more (a surface that can be recognized as bent by the eye), the curvature and the unevenness difference higher than that In the case of printing on a curved surface having, the blanket may not be printed even if the thickness of the blanket is twice or more the unevenness difference. In particular, this tendency is strong when there are many irregularities on the curved surface, and in order to follow the surface of the curved surface, a blanket thickness that allows deformation of the surface is required. The thickness of the blanket may be determined depending on the curved surface to be printed. For example, the thickness of the blanket can be 5 mm or more.
On the other hand, the maximum thickness of the blanket 3 is limited by the surface shape of the substrate when the roll diameter is small, and is not particularly limited when the roll diameter is large. Therefore, the blanket used in the printing apparatus of the present invention can be thickened so as to be sufficiently deformable along the curved surface shape of the printing object.
Of course, the size of the blanket is limited by physical limitations, such as the size of the printing device, but it is similar to a conventional printing machine.

  The blanket 3 employed in the apparatus 1 of the present invention is also preferably composed of at least the surface 5 of the blanket 3 of polydimethylsiloxane (PDMS), which is substantially one of the elastomers. This is because PDMS can control the surface energy by mixing additives or the like, and can obtain a product having a relatively high surface energy. Moreover, it can be set as the blanket which has the softness which elastically deforms according to the surface shape of to-be-printed material by making the whole blanket 3 consist of PDMS substantially.

  Referring to FIG. 2, a blanket 3 employed in the printing apparatus 1 of the present invention is a cylindrical sleeve 11 having a laminated structure in which an outer layer 12 including a surface 5 of the blanket 3 is provided on an inner layer 13. Can be provided. Using PDMS as a blanket material, supplying ink containing an organic solvent from the slit coater to the surface of the blanket, forming an ink film on the surface of the blanket, and repeating printing, the organic solvent is absorbed by PDMS, PDMS can degrade over time. In addition, the surface of the blanket may deteriorate due to physical contact with the substrate. By providing the blanket 3 with a multilayer structure including the outer layer 12 and the inner layer 13, it is possible to replace only the outer layer 12 including the surface 5 that is easily deteriorated, which is economical. It is also possible to select and replace the outer layer 12 that is optimal for different inks depending on the type of ink.

The outer layer 12 and the inner layer 13 of the blanket 3 are such that the outer layer 12 has a higher rubber hardness than the inner layer 13, and the thickness of the outer layer 12 is larger than the thickness of the inner layer 13 in the diameter direction of the blanket 3. Is preferably small. By doing so, the outer layer 12 can be made thin and suitable for slit coating, and the inner layer 13 can be made thick and soft.
The outer layer 12 and the inner layer 13 of the blanket 3 may be made of the same material (for example, both are PDMS), and different materials (for example, the outer layer 12 is PDMS and the inner layer 13 is sponge rubber). ).

  The outer layer 12 and the inner layer 13 of the blanket 3 are bonded to each other by the tack property of the lower surface of the outer layer 12 and the upper surface of the inner layer 13 between the lower surface of the outer layer 12 and the upper surface of the inner layer 13. be able to. In this case, it is not necessary to bond the outer layer 12 and the inner layer 13 with an adhesive or the like, so that the outer layer 12 can be easily replaced and is economical.

The viscosity of the ink employed in the apparatus of the present invention is preferably 1 to 150 mPa · s. In particular, in the present invention, since it is necessary to supply ink from the slit coater to the surface of the blanket, it is preferable to use ink having a relatively low viscosity.
As the ink, water-based inks used in normal reverse offset printing can be used. Since water-based ink generally has a large surface tension, it is preferable to use a blanket having a high surface energy.
In addition, an ink used in normal gravure offset printing can be diluted with an organic solvent (such as isophorone or butyl carbitol acetate (BCA)). Such an ink is suitably used for forming an antireflection film, a light shielding film, or the like in an optical application.

  The printing apparatus of the present invention may further include drying means such as a heater, a dryer, and a blower. The drying means dries at least a part of the ink film formed on the surface of the blanket prior to transferring at least a part of the ink film formed on the surface of the blanket to the printing material. By doing so, it becomes possible to transfer the ink film formed on the surface of the blanket to the printing material better.

Referring to FIG. 3, the apparatus of the present invention may further include an intaglio 14. The intaglio 14 peels at least a part of the ink film 8 formed on the surface 5 of the rotating blanket 3 before at least a part of the ink film 8 is transferred to the substrate. By doing in this way, it becomes possible to print the pattern of the same shape as the recessed part of an intaglio.
As the intaglio, various plates such as glass, metal and resin can be used. By using a plate, it is possible to form a wide pattern with high surface flatness, which cannot be formed by a normal printing technique, from a fine pattern.
When part of the ink on the surface of the blanket is peeled off by the intaglio, it is preferable that the concave portion of the intaglio is deep so that the blanket does not contact the bottom surface of the concave portion of the plate. The depth depends on the rubber hardness of the blanket or the material of the plate and the production method, but a depth of 20 to 300 micrometers is preferable for a glass plate or a metal plate, and 1 to 5 millimeters for a resin plate. Depth is preferred.
As another means for preventing the blanket from coming into contact with the bottom of the plate recess, it is preferable that the blanket 3 has a multilayer structure including an outer layer and an inner layer, and the outer layer has a rubber hardness higher than that of the inner layer. Specifically, the rubber hardness of the inner layer is 5 to 40 in ASKER C, while the rubber hardness of the outer layer is 5 to 50 in SHORE A.
When the blanket employed in the printing apparatus of the present invention has a laminated structure including an outer layer and an inner layer, if the hard outer layer is thick, there is a possibility that good printing cannot be performed on a curved surface. Therefore, it is preferable to make the outer layer as thin as possible. Specifically, when the outer layer is hard, it is preferable to have a thickness of about 0.3 to 1 millimeter.

Referring to FIG. 4, the apparatus of the present invention can operate as follows.
That is, first, ink is supplied to the slit coater 2. Next, while rotating the blanket 3 in the direction of the arrow, ink is supplied from the tip of the slit coater 2 to the surface of the blanket 3, and an ink film 8 supplied from the slit coater 2 is formed on the surface of the blanket 3. This is suitably dried.
During this time, the substrate 9 and the intaglio plate 14 placed on the substrate stage 15 and the intaglio stage 16 that can move in the direction of the arrow respectively stand by at the standby positions A and C.
Next, the intaglio stage 16 is moved below the blanket 3, and at least a part of the ink film 8 on the surface of the blanket 3 is peeled off by the intaglio 14.
Next, the substrate stage 15 is moved below the blanket 3, the substrate stage 15 is moved while rotating the blanket 3 in the direction of the arrow, and at least a part of the ink film 8 on the surface of the blanket 3 is printed. Transfer to 9.
Here, without performing the peeling process using the intaglio plate 14, the ink film 8 may be formed on the surface of the blanket 3 and then dried, and the ink film 8 may be transferred to the substrate 9 to form a solid film.
A blanket cleaning mechanism 17 can be provided to clean the surface of the blanket 3 after printing is completed. As the blanket cleaning mechanism 17, for example, a metal roll or an adhesive tape having a roll shape can be used. The blanket cleaning mechanism 17 is preferably arranged so that the blanket 3 and the central axis are parallel to each other, and the blanket cleaning mechanism 17 preferably has a diameter different from that of the blanket 3.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Slit coater 3 Blanket 7 Ink 9 Substrate 14 Intaglio 15 Substrate stage 16 Intaglio stage

Claims (20)

A printing apparatus comprising a slit coater and a blanket,
The slit coater is disposed such that a predetermined gap is provided between the tip of the slit coater and the surface of the blanket, and supplies ink from the tip of the slit coater to the surface of the blanket.
In the blanket, the ink supplied from the slit coater forms a film on the surface of the blanket, and at least a part of the film of the ink is transferred to the printed material. At this time, the surface of the blanket is the surface of the printed material. The printing apparatus that is elastically deformed according to a surface shape.   The printing apparatus according to claim 1, wherein the surface energy of the blanket is 20 mN / m or more.   The printing apparatus according to claim 1, wherein at least a surface of the blanket is substantially made of polydimethylsiloxane.   The printing apparatus according to claim 1, wherein the blanket has a laminated structure in which an outer layer including a surface of the blanket is provided on the inner layer.   The printing apparatus according to claim 4, wherein the outer layer has a higher rubber hardness than the inner layer.   The printing apparatus according to claim 4, wherein the blanket has a thickness of the outer layer smaller than a thickness of the inner layer in a diameter direction of the blanket.   5. The blanket according to claim 4, wherein the lower surface of the outer layer and the upper surface of the inner layer are bonded to each other by tackiness of at least one of the lower surface of the outer layer and the upper surface of the inner layer. The printing apparatus of any one of -6.   The printing apparatus according to claim 1, wherein the ink has a viscosity of 1 to 150 mPa · s. A drying means,
The drying means dries at least a part of the ink film formed on the surface of the blanket prior to transferring at least a part of the ink film to the substrate. The printing apparatus according to any one of 1 to 8. An intaglio
2. The intaglio is configured to peel at least a part of the ink film formed on the surface of the blanket before at least a part of the ink film is transferred to a printing material. The printing apparatus of any one of -9. Supplying ink to the slit coater;
Supplying ink from the tip of the slit coater to the surface of the blanket while rotating the blanket, and forming a film of ink supplied from the slit coater on the surface of the blanket; and at least of the ink film Including a step of transferring a part to a substrate;
A predetermined gap is provided between the tip of the slit coater and the surface of the blanket,
The printing method according to claim 1, wherein the surface of the blanket is elastically deformed according to the surface shape of the substrate.   The printing method according to claim 11, wherein a surface energy of the blanket surface is 20 mN / m or more.   The printing method according to claim 11 or 12, wherein at least a surface of the blanket is substantially made of polydimethylsiloxane.   The printing method according to any one of claims 11 to 13, wherein the blanket has a laminated structure in which an outer layer including a surface of the blanket is provided on the inner layer.   The printing method according to claim 14, wherein the outer layer has a higher rubber hardness than the inner layer.   The printing method according to claim 14, wherein the blanket has a thickness of the outer layer smaller than a thickness of the inner layer in a diameter direction of the blanket.   15. The blanket according to claim 14, wherein the lower surface of the outer layer and the upper surface of the inner layer are bonded to each other by tackiness of at least one of the lower surface of the outer layer and the upper surface of the inner layer. The printing method of any one of -16.   The printing method according to claim 11, wherein the ink has a viscosity of 1 to 150 mPa · s. The method further comprises a step of drying at least a part of the ink film formed on the surface of the blanket prior to the step of transferring at least a part of the ink film to the substrate. Item 19. The printing method according to any one of Items 11 to 18. Prior to the step of transferring at least part of the ink film to the substrate, the method further comprises the step of peeling at least part of the ink film formed on the surface of the blanket with an intaglio. The printing method according to any one of claims 11 to 19.

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