JP4656948B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus used for precision printing of a fine pattern by an offset printing method.

For manufacturing electrode substrates for plasma display panels (PDP), electrode substrates for electroluminescent (EL) elements, etc., a fine and thick electrode pattern having a line width of about 10 to 200 μm and a thickness of about 0.1 to 10 μm. Is required to be precisely formed. In recent years, it has been studied to employ an offset printing method for forming such a pattern.
Among offset printing, in particular, when a blanket (transfer body) is a silicone blanket with good ink transferability (releasability) to the printing medium, pattern reproducibility is early in continuous printing. It is extremely high and can form a pattern with an excellent printed shape. However, when printing is repeated, the blanket swells with the solvent of the ink, and its wetting characteristics change every moment. Inconveniences such as transfer and a decrease in transferability of ink to the printing medium occur. On the other hand, when a solvent that does not easily swell the blanket is used as the solvent for the ink, a change in wettability can be suppressed, but there is a problem that the acceptability of the ink from the plate to the blanket is lowered.

Therefore, various means have been proposed to stabilize the wettability of the blanket.
For example, Patent Document 1 discloses a printing apparatus that adjusts the impregnation amount of an ink solvent by bringing an endless belt-shaped moisture absorbent sheet into contact with the surface of a printing blanket, and Patent Documents 2 and 3 include a printing blanket. There have been proposed printing apparatuses that remove the solvent of the ink (the “transfer material” referred to in Patent Document 2) absorbed by the printing blanket by contacting the solvent absorber with the solvent absorber. .

In addition, the surface of the silicone rubber has a free low molecular weight polysiloxane compound (silicone oil), and this results in excellent release properties of the silicone blanket. A printing method in which silicone oil with low interfacial tension is applied to the surface layer of the blanket (Patent Document 4) or a low molecular weight polysiloxane compound is blended in advance with the printing ink, so that only the ink solvent is added to the printing blanket. There has been proposed a printing method (Patent Document 5) for absorbing a low molecular weight polysiloxane compound.
JP 2000-158620 A JP 2000-158633 A JP-A-8-156388 Japanese Patent No. 2993846 JP 2004-66804 A

  However, according to the printing apparatus described in Patent Documents 1 to 3 in which a moisture absorbing sheet or a solvent absorber is brought into contact with the blanket to remove the solvent of the ink, at the same time, the low molecular weight polysiloxane contained in the silicone blanket from the beginning. Since even the compound is absorbed, it is difficult to stabilize the transfer property of the ink from the blanket to the printing medium. In addition, in the printing apparatuses described in Patent Documents 2 and 3, since the blanket is moved to the solvent absorber or the solvent absorber is wound around the surface of the blanket, the process becomes complicated and the productivity is reduced. There is a fear.

Further, the printing method described in Patent Document 4 does not consider removing the ink solvent from the silicone blanket, and thus cannot solve the problems associated with the swelling of the blanket.
Furthermore, in the printing method described in Patent Document 5, since the low molecular weight polysiloxane compound is absorbed into the silicone blanket together with the ink solvent, the efficiency of allowing the low molecular weight polysiloxane compound to penetrate into the silicone blanket is low.

  Therefore, an object of the present invention is to stabilize the wettability characteristics of the silicone blanket and the content of the low molecular weight polysiloxane compound and maintain the printing accuracy, ink transferability and acceptability in a good state over a long period of time. A printing apparatus is provided.

In order to achieve the above object, the present invention provides:
(1) A silicone blanket fixed to the outer peripheral surface of a rotatable blanket cylinder, an endless belt in contact with the silicone blanket , and a ring of the endless belt, the endless belt being attached to the silicone blanket And a plurality of pulleys for driving the endless belt to move around the silicone blanket, and the endless belt is made of a solvent absorber. It is divided into two regions, a first region formed and a second region formed by a polysiloxane carrier, and when it comes into contact with the silicone blanket, the solvent of the ink contained in the silicone blanket is removed from the silicone blanket. Solvent absorption hand to absorb When, characterized that you have combines both means polysiloxane supply means for supplying a low molecular weight polysiloxane to the silicone blanket, a printing apparatus,
(2) In the nip portion where the two pulleys are the contact portions between the endless belt and the silicone blanket, the endless belt can move with respect to the nip portion along the rotational direction of the silicone blanket. The printing apparatus according to (1), wherein the printing device is disposed on the upstream side and the downstream side in the rotation direction of the silicone blanket.
(3) The printing according to (1) or (2), further including a roller disposed outside the ring of the endless belt and contacting the endless belt from the outside of the ring of the endless belt. apparatus.
(4) a drying means for drying the endless belt, and a polysiloxane providing means for including a low molecular weight polysiloxane compound to said endless belt, said drying means, in the first region, wherein the contact member is dried, the polysiloxane applying means, in the second region, characterized in that the inclusion of low molecular weight polysiloxane compound to said endless belt, according to any one of (1) to (3) Printing device.
(5) The first region has a surface layer including a surface in contact with the silicone blanket, and the surface layer is made of rubber not including a plasticizer and an anti-aging agent. The printing apparatus according to any one of ( 1 ) to (4).

  According to the printing apparatus of the present invention, since the solvent absorption means and the polysiloxane supply means are provided, the swelling state of the silicone blanket and the content of the low molecular weight polysiloxane compound are individually and appropriately, The surface condition of the silicone blanket can be kept constant. Therefore, printing accuracy, ink transferability and acceptability can be maintained in a good state for a long period of time.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a printing apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of a printing apparatus according to the design change example of FIG.
1 and 2 includes a silicone blanket 11, a blanket cylinder 12, endless belts 13 and 13 'serving as contact members, a pulley 16 serving as a driving unit, and a blower serving as a drying unit. And a controller 17 for controlling the driving means, the drying means, and the polysiloxane supply means.

The silicone blanket 11 is not particularly limited, except that at least the surface layer including the ink carrying surface is formed of silicone rubber, and various silicone blankets can be used. This silicone blanket 11 is used by being fixed to an outer peripheral surface of a blanket cylinder 12 described later.
The silicone rubber is not particularly limited, and may be any type such as a room temperature curable silicone rubber (RTV) and a heat curable silicone rubber (HTV). Among these, it is preferable from the viewpoint of improving the dimensional accuracy of the silicone blanket to use a room temperature curing type addition type silicone rubber which does not generate a by-product when the silicone rubber is cured.

  Although the hardness of the said surface layer is not specifically limited, 20-70 are preferable by durometer hardness (type A), and 30-60 are more preferable. When the hardness of the surface layer exceeds the above range, it becomes difficult to deform, and the acceptability of the ink from the plate and the transferability of the ink to the printing medium may be reduced. On the other hand, if the hardness of the surface layer is below the above range, the amount of deformation becomes too large, and the printing accuracy may be reduced.

The surface roughness of the surface layer is not particularly limited, but usually it is preferably as small as possible. For example, when printing an extremely fine pattern having a line width of about 20 μm, the surface roughness (10-point average roughness Rz) of the silicone blanket is preferably 1.0 μm or less, and is 0.5 μm or less. Is more preferable.
The thickness of the surface layer is not particularly limited, but generally, if the surface layer exceeds 1.5 mm, the deformation becomes large and the printing accuracy may be lowered, so it is set within 1.5 mm. It is preferable.

An example of the moving means for rotating the silicone blanket 11 is a blanket cylinder 12. The blanket cylinder 12 is not particularly limited, and the same blanket cylinder used in a known printing apparatus can be used.
An example of the contact member that comes into contact with the silicone blanket 11 is the endless belt 13 shown in FIG. The endless belt 13, when in contact with the silicone blanket 11, serves to absorb the solvent of the ink contained in the silicone blanket 11 from the silicone blanket 11 and to supply low molecular weight polysiloxane to the silicone blanket 11. It combines both means with the polysiloxane supply means.

In the endless belt 13, approximately half of the endless belt 13 is partitioned as the first region 14 in the moving direction of the relative movement with respect to the silicone blanket 11, that is, in the moving direction y of the circular movement, and the remaining approximately half is partitioned as the second region 15. .
The endless belt 13 is not limited to this, but, for example, an endless belt base material made of a resin film or metal, which will be described later, and a rubber or elastomer (solvent absorber, described later) for absorbing the solvent of the ink. Using a rubber or an elastomer (polysiloxane carrier described later) for supplying polysiloxane, it can be produced according to the following methods (I) and (II).
(I) A sheet made of a solvent absorber and a sheet made of a polysiloxane carrier are prepared in advance by means of coating or the like, and these sheets are attached to predetermined regions 14 and 15 on the belt substrate. wear.
(II) In advance, one of the first region 14 and the second region 15 on the belt base material is masked, and the other region is coated with a solvent absorber or a polysiloxane carrier. Further, the surface (the other region) of the coating layer thus obtained is masked, and the one of the solvent absorber and the polysiloxane carrier that is not used for the previous coating is coated on the one region.

Although it does not specifically limit as a resin film which forms a belt base material, For example, a polyethylene terephthalate (PET), a polybutylene terephthalate (PBT), a polycarbonate (PC), a polyimide (PI), a polyamideimide (PAI), a polyarylate etc. The film which consists of these resin is mentioned.
Moreover, as a metal which forms a belt base material, stainless steel, nickel, iron etc. are mentioned, for example.

The solvent absorbing means is provided in the first region 14 of the endless belt 13. The first region 14 is a region that can absorb the solvent of the ink contained in the silicone blanket 11 when being in contact with the silicone blanket 11.
The first region 14 is formed by a solvent absorber. The solvent absorber is appropriately selected according to the ink used for printing, and is not particularly limited, and examples thereof include rubber that easily absorbs the solvent of the ink. Specific examples include ethylene-propylene-diene copolymer rubber (EPDM), silicone rubber, urethane rubber, natural rubber (NR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), and the like. .

The solvent absorber is preferably a material having low contact contamination. Specifically, it is preferable to use a so-called plastic-free rubber composition that does not contain a plasticizer and an anti-aging agent (more preferably, a plasticizer, an anti-aging agent, and a softening agent).
In addition, it is necessary from the viewpoint of workability of a rubber material to select a rubber material having a small molecular weight and Mooney viscosity as a rubber not containing a plasticizer, an antioxidant, and a softening agent. Also, a so-called reactive plasticizer having a functional group capable of undergoing a crosslinking reaction with rubber at the end of the plasticizer is suitably used in the present invention because it reduces the hardness of the rubber material while keeping the contact contamination low. .

Further, since there is a possibility that the light resistance may be lowered by not adding an anti-aging agent, rubber materials having no unsaturated double bond, specifically, EPDM, silicone rubber, etc. It is preferable to use a rubber material having few heavy bonds.
The solvent absorber is not particularly limited because it varies depending on the solvent of the ink used for printing. For example, the weight change rate after being immersed in the ink solvent at 23 ° C. for 24 hours is in the range of 5 to 400% by weight. It is preferable that When the weight change rate under the above conditions is less than 5%, the ink solvent absorption efficiency is lowered, and the ink acceptability is lowered. There is no choice but to reduce printing productivity. On the other hand, when the rate of weight change under the above conditions exceeds 400%, the first region 14 of the contact member 13 may be excessively swollen, and the contact member 13 may be softened or broken. The weight change rate under the above conditions is preferably 10 to 300% in the above range.

Ink solvent absorption processing by the solvent absorption means such as the first region 14 of the endless belt 13 includes printing processing and low molecular weight polysiloxane compound supply processing by the polysiloxane supply means such as the second region 15 described later. It is controlled by the control unit 20 described later so that it is executed only when it is not.
The polysiloxane supply means is provided in the second region 15 of the endless belt 13. The second region 15 is a region in which a low molecular weight polysiloxane compound can be supplied to the silicone blanket 11 when being in contact with the silicone blanket 11.

The second region 15 is formed by a polysiloxane carrier. The polysiloxane carrier is not particularly limited, and examples thereof include silicone rubber, EPDM, urethane rubber, natural rubber (NR), chloroprene rubber (CR), and acrylonitrile-butadiene copolymer rubber (NBR).
The polysiloxane carrier is preferably a material having low contact contamination like the solvent absorber forming the first region 14. Specifically, it is preferable to use a so-called plastic-free rubber composition that does not contain a plasticizer and an anti-aging agent (more preferably, a plasticizer, an anti-aging agent, and a softening agent).

The supply process of the low molecular weight polysiloxane compound by the polysiloxane supply means such as the second region 15 of the endless belt 13 includes the printing process and the ink solvent absorption process by the solvent absorption means such as the first region 14 described above. It is controlled by the control unit 20 described later so that it is executed only when it is not.
The pulley 16 is a member for driving the endless belt 13 to move relative to the silicone blanket 11 (in the case of the endless belt 13 shown in FIG. Two or more are arranged in the. The shape and forming material of the pulley 16 are not particularly limited, and the same pulleys as known pulleys used to drive and move the endless belt-like member can be used.

In the nip portion 19 that is a contact portion between the endless belt 13 and the silicone blanket 11, two pulleys 16 a and 16 b are provided in the nip portion 19 so that the endless belt 13 can move along the rotational direction x of the silicone blanket 11. On the other hand, the silicone blanket 11 is disposed on the upstream side and the downstream side in the rotation direction x.
By arranging the two pulleys 16a and 16b in this way, the contact portion between the endless belt 13 and the silicone blanket 11 can be widened.

  As an example of the design change of the endless belt, for example, as shown in FIG. 2, an endless belt 13 'having a long circumferential length can be cited. By extending the circumference of the endless belt, the first region 14 and the second region 15 can be widened, so that the solvent of the ink contained in the silicone blanket 11 can be absorbed or a low molecular weight polysiloxane compound can be supplied to the silicone blanket 11. When the number of rotations of the silicone blanket 11 and the endless belt 13 'is small, a sufficient effect can be obtained.

In the endless belt 13 ′ shown in FIG. 2, not only the pulley 16 ′ disposed in the ring of the endless belt 13 ′ but also a roller 160 that contacts the endless belt 13 ′ is disposed outside the ring. By using the roller 160, even the endless belt 13 ′ having a long circumference can be arranged compactly.
The contact member is not limited to an endless belt-like member, and may be, for example, a drum-like member that moves relative to the silicone blanket 11 by rotating.

As a drying means for evaporating and removing the ink solvent absorbed in the first region 14 of the endless belt 13 by heating and drying, for example, a blower 17 may be mentioned.
The air blower 17 is not specifically limited, For example, what is necessary is just what can spray the hot air of the temperature required in order to volatilize the solvent of an ink. Further, for example, an infrared (IR) heater can be used instead of the blower 17.

The drying process by the drying means such as the blower 17 is controlled so as to be executed only when the first region 14 of the endless belt 13 faces the drying means by synchronizing with the rotation of the endless belt 13. The
The drying means such as the blower 17 is not limited to this. For example, the drying means is downstream of the contact portion (nip portion 19) between the silicone blanket 11 and the endless belt 13 in the circumferential movement direction y of the endless belt 13. From the viewpoint of efficiently volatilizing and removing the solvent of the ink absorbed in the first region 14, it is preferable to dispose it on the upstream side in the circumferential movement direction y from the polysiloxane applicator 18 described later. In this case, the cooling time of the silicone blanket 11 can be increased.

  After the contact member 13 is heated and the solvent of the ink is volatilized, when the contact member 13 is contacted with the silicone blanket 11 while the temperature of the contact member 13 remains high, the blanket 11 is heated and contacts the blanket 11. There is a risk of heating and expanding the printing plate (not shown). Therefore, it is preferable that a member for cooling the endless belt 13 is newly provided after the ink solvent is volatilized, or the blower 17 can be blown with not only hot air but also cold air. . In particular, when both the hot air and the cold air can be blown by the blower 17, overheating of the endless belt 13 can be suppressed while simplifying the printing apparatus.

Examples of the polysiloxane applying means for applying the low molecular weight polysiloxane compound to the second region 15 of the endless belt include a polysiloxane applicator 18.
The polysiloxane applicator 18 is not particularly limited. For example, the polysiloxane applicator 18 is connected to a tank for storing a low molecular weight polysiloxane compound, and appropriately applies a low molecular weight polysiloxane compound to the second region 15 of the endless belt 13. Anything can be used.

The application process by the polysiloxane application unit such as the polysiloxane application unit 18 is executed only when the second region 15 of the endless belt 13 faces the polysiloxane application unit by synchronizing with the rotation of the endless belt 13. To be controlled.
The polysiloxane applicator 18 is not limited to this. For example, the polysiloxane applicator 18 is located upstream of the nip portion 19 in the circumferential movement direction y of the endless belt 13 and downstream of the blower 17 in the circumferential movement direction y. Arrangement is preferable in terms of the efficiency of the operation of supplying the applied polysiloxane to the silicone blanket 11.

The low molecular weight polysiloxane compound is not particularly limited, and examples thereof include dimethyl silicone oil, methyl phenyl silicone oil, and methyl hydrogen silicone oil having a molecular weight of about 100 to 3000, preferably about 100 to 2000.
The proper amount of the low molecular weight polysiloxane supplied to the silicone blanket 11 is not particularly limited. Usually, the silicone blanket has a weight ratio with respect to the silicone rubber, and the repeating number n of the bifunctional repeating unit D is 3 to 3. Since the low molecular weight polysiloxane compound of 20 (D _{3 to} D ₂₀ ) is contained in an amount of 1000 to 10000 ppm, even after the low molecular weight polysiloxane is supplied to the silicone blanket 11 using the contact member 13, the silicone blanket 11 It is preferable to adjust so that the content of the low-molecular-weight polysiloxane in the same level.

As control means for controlling the driving of the endless belt 13, the drying of the first region 14 of the endless belt 13, and the application of the low molecular weight polysiloxane compound to the second region 15 of the endless belt 13, for example, a CPU or the like The control part 20 provided with these is mentioned.
The process of driving the endless belt 13 to absorb the solvent of the ink from the silicone blanket 11 in the first region 14 and the process of applying the low molecular weight polysiloxane compound to the silicone blanket 11 in the second region are, for example, silicone. When the ink pattern is transferred from the blanket 11 to the substrate to be printed, and changes in the line width, printing shape, printing accuracy, etc. of the obtained printing pattern are observed, and when a predetermined amount of change in the line width is reached Just do it.

Specifically, for example, when the line width of the print pattern increases by 10% or more, preferably 5% or more with respect to the line width (reference value) required for the print pattern, the first width of the endless belt 13 is increased. The region 14 and the silicone blanket 11 are brought into contact with each other to perform a process of absorbing the ink solvent from the silicone blanket 11.
On the other hand, when the shape of the printed pattern is disturbed and it is determined that the transferability of the ink is reduced (for example, when the occurrence of piling is observed, that is, complete transfer of the ink (100% transfer) is achieved. When it becomes impossible, the second region 15 of the endless belt 13 and the silicone blanket 11 are brought into contact with each other, and a process of supplying a low molecular weight polysiloxane compound to the silicone blanket 11 is executed.

FIG. 3 is a block diagram showing a configuration of a printing apparatus according to another embodiment of the present invention.
The printing apparatus 30 shown in FIG. 3 includes a silicone blanket 11, a blanket cylinder 12, a first endless belt (first contact member) 33 as a solvent absorbing means, and a pulley 34 as a driving means for the first endless belt 33. The second endless belt (second contact member) 35 as the polysiloxane supply means, the pulley 36 as the driving means of the second endless belt 35, the blower 17 as the drying means, and the polysiloxane as the polysiloxane applying means A siloxane applicator 18 and a controller 21 for controlling the driving means, the drying means, and the polysiloxane supply means are provided.

The silicone blanket 11 and the blanket cylinder 12 are the same as described above.
Examples of the first contact member that is in contact with the silicone blanket 11 include the first endless belt 33. The first endless belt 33 is a solvent absorbing means that can absorb the solvent of the ink contained in the silicone blanket 11 from the silicone blanket 11 when being in contact with the silicone blanket 11.

The first endless belt 33 is not limited to this, but can be obtained, for example, by coating a solvent absorber on an endless belt substrate made of the above-described resin film or metal.
Examples of the belt base material and the solvent absorber include those described above.

The first contact member is not limited to an endless belt-like member, and may be, for example, a drum-like member that moves relative to the silicone blanket 11 by rotating.
The ink solvent absorption process by the solvent absorption unit such as the first endless belt 33 is not performed by the printing process or the low molecular weight polysiloxane compound supply process by the polysiloxane supply unit such as the second endless belt 35 described later. It is controlled by the control unit 21 described later so as to be executed only occasionally.

As a drying means for evaporating, removing, and drying the ink solvent absorbed by the first endless belt 33, a drying means similar to that described above, such as the blower 17, is used. Can be mentioned.
A second endless belt 35 is an example of the second contact member that comes into contact with the silicone blanket 11. The second endless belt 35 is a polysiloxane supply means capable of supplying a low molecular weight polysiloxane compound to the silicone blanket 11 when being in contact with the silicone blanket 11.

The second endless belt 35 is not limited to this, but can be obtained, for example, by coating a polysiloxane carrier on an endless belt substrate made of the above-described resin film or metal.
Examples of the belt base material and the polysiloxane support are the same as those described above.

The second contact member is not limited to an endless belt-like member, and may be, for example, a drum-like member that moves relative to the silicone blanket 11 by rotating.
In the supply process of the low molecular weight polysiloxane compound by the polysiloxane supply means such as the second endless belt 35, the printing process and the ink solvent absorption process by the solvent absorption means such as the first endless belt 33 are not executed. It is controlled by the control unit 21 described later so as to be executed only occasionally.

Examples of the polysiloxane applying means for applying the low molecular weight polysiloxane compound to the second endless belt 35 include polysiloxane applying means similar to those described above, such as the polysiloxane applicator 18.
Moreover, as a low molecular weight polysiloxane compound, the same thing as mentioned above is mentioned. The supply amount of the low molecular weight polysiloxane compound is also preferably adjusted in the same manner as described above.

  The pulleys 34 and 36 drive the first endless belt 33 and the second endless belt 35, respectively, and move relative to the silicone blanket 11 (in the case of the endless belts 33 and 35 shown in FIG. 3, the circular movement). And two or more members are disposed in the ring of the endless belts 33 and 35. The shape and forming material of the pulleys 34 and 36 are not particularly limited, and the same pulleys as known pulleys used for driving and rotating the endless belt-like member can be used.

  In the nip portion 39 that is a contact portion between the first endless belt 33 or the second endless belt 35 and the silicone blanket 11, two pulleys are provided so that the endless belt 13 can move along the rotational direction x of the silicone blanket 11. (34a and 34b or 36a and 36b) are arranged on the upstream side and the downstream side in the rotational direction x of the silicone blanket 11 with respect to the nip portion 19.

By arranging the two pulleys in this way, the contact portion between the first endless belt 33 or the second endless belt 35 and the silicone blanket 11 can be widened.
As control means for controlling the driving of the first endless belt 33 and the second endless belt 35, the drying of the first endless belt 33, and the application of the low molecular weight polysiloxane compound to the second endless belt 35, for example, The control part 21 provided with CPU etc. is mentioned.

  The process of driving the first endless belt 33 to absorb the solvent of the ink from the silicone blanket 11 and the process of driving the second endless belt 35 to impart the low molecular weight polysiloxane compound to the silicone blanket 11 include, for example: The ink pattern was transferred from the silicone blanket 11 to the substrate, and changes in the line width, printing shape, printing accuracy, etc. of the obtained printing pattern were observed, and the amount of change set in advance for the line width, etc. was reached. It can be done sometimes.

Specifically, for example, when the line width of the print pattern increases by 10% or more, preferably 5% or more with respect to the line width (reference value) required for the print pattern, the first endless belt 33 and The silicone blanket 11 is brought into contact with the silicone blanket 11 to absorb the ink solvent.
On the other hand, when the shape of the printed pattern is disturbed and it is determined that the transferability of the ink is reduced (for example, when the occurrence of piling is observed, that is, complete transfer of the ink (100% transfer) is achieved. When it becomes impossible, the second endless belt 35 and the silicone blanket 11 are brought into contact with each other, and a process of supplying a low molecular weight polysiloxane compound to the silicone blanket 11 is executed.

  In the printing apparatus shown in FIGS. 1 to 3, an endless belt 13 as a solvent absorbing means and a polysiloxane supply means, a first endless belt 33 as a solvent absorption means, and a second endless belt 35 as a polysiloxane supply means are: These can be arranged so as to be separated from and contactable with the silicone blanket 11. Further, when the ink solvent absorption process and the low molecular weight polysiloxane supply process are not performed, these are separated from the silicone blanket 11 and the corresponding endless belt is attached to the silicone only when the above process is performed. By bringing it into contact with the blanket 11, an ink solvent absorption process and a low molecular weight polysiloxane supply process can be performed without reducing printing productivity.

  In the printing apparatus of the present invention, the printing plate is not particularly limited, and various printing plates such as an intaglio plate, a lithographic plate, a waterless lithographic plate, and a relief plate can be used. In particular, it is required to print and form an extremely fine pattern, particularly an extremely fine and thick film pattern, such as an electrode pattern on a PDP electrode substrate or an EL element electrode substrate. In use, intaglio is preferably used.

Next, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited by the following Example.
<Print formation of fine pattern>
Example 1
A fine pattern was printed and formed on the surface of the front plate of the following plasma display panel (PDP) using the following printing apparatus, intaglio and ink.

As shown in FIG. 1, a printing apparatus 10 including a silicone blanket 11, a blanket cylinder 12, an endless belt 13, a pulley 16, a blower 17, a polysiloxane applicator 18, and a control unit 20 was used as the printing apparatus.
The silicone blanket 11 has a thickness of 300 μm and a rubber hardness of 40 (durometer hardness, type A; polymer meter) formed on a polyethylene terephthalate (PET) base material using a room temperature curable addition type silicone rubber. Measured with a JIS-A type hardness meter manufactured by Co., Ltd. The same applies hereinafter.) A surface layer having a 10-point average roughness (Rz) of 0.1 μm is fixed to the outer peripheral surface of the blanket cylinder 12 and used. did. The length of the silicone blanket 11 in the rotational direction x of the silicone blanket 11 was 700 mm.

  The endless belt 13 is formed by using ethylene-propylene-diene copolymer rubber (EPDM) on a PET belt base material and has a thickness of 350 μm and a rubber hardness of 30 (durometer hardness, type A). A first region 14 made of a body and a second region 15 made of silicone rubber and made of a polysiloxane carrier having a thickness of 350 μm and a rubber hardness of 30 (durometer hardness, type A). used.

  The solvent absorber was formed without blending any plasticizer and anti-aging agent with respect to the EPDM, and was immersed in diethylene glycol monobutyl ether acetate (butyl carbitol acetate) at 23 ° C. for 24 hours. The subsequent weight change rate was 35% by weight. Moreover, the length of the 1st area | region 14 in the rotation direction x of the silicone blanket 11 was 700 mm, and the length of the 2nd area | region 15 was 700 mm.

The silicone blanket 11 includes a silicone rubber layer (elastic body layer) having a thickness of 0.55 mm on a PET film (base material) having a thickness of 0.35 mm. Used).
The blower 17 was a dryer (blower 25; 1200 W) capable of blowing both hot air (about 120 ° C.) and cold air (about 10 ° C.).

A low molecular weight polydimethylsiloxane having a molecular weight of 100 to 2000 was used as the low molecular weight polysiloxane compound dropped from the polysiloxane applicator 18 onto the second region 15 of the endless belt 13.
As the printing pattern, a stripe pattern having a line width of 90 μm and a pitch of 360 μm was adopted. As the intaglio plate, a soda lime glass substrate having a concave portion with a depth of 30 μm corresponding to the printing pattern was used. .

For the ink, silver powder (average particle size (50% particle size) 0.8 μm) 900 parts by weight, glass frit (average particle size (50% particle size) 0.5 μm) 50 to 100 parts by weight of acrylic resin A conductive paste obtained by blending parts by weight and 200 parts by weight of butyl carbitol acetate (solvent) and dispersing and mixing with three rolls was used.
The front plate of the PDP, which is the substrate to be printed, is a high strain point glass plate (Asahi Glass (42 inches)) with a width of about 92.0 cm, a height of about 51.8 cm, a thickness of 2.8 mm, and a diagonal of about 105.6 cm (42 inches) The model number “PD200” manufactured by the same company) was used.

  The printing process was carried out at a transfer speed from the intaglio to the silicone blanket of 30 mm / second and from the silicone blanket to the substrate to be printed at 100 mm / second, and the printing pressure was such that the nip width of the silicone blanket was 10 mm. It was adjusted. The printing process was performed on 500 sheets to be printed while performing the solvent absorption process and the polysiloxane supply process using the endless belt 13.

The solvent absorption treatment was performed when the line width of the print pattern increased by 10% or more with respect to the reference value. In addition, the polysiloxane supply treatment was performed when piling was observed during the transfer of ink from the silicone blanket to the substrate.
Example 2
A printing apparatus 30 shown in FIG. 3 was used as a printing apparatus in place of the printing apparatus 10 shown in FIG.

  The first endless belt 33 is formed on a PET belt substrate using EPDM, and has a thickness of 350 μm and a rubber absorber having a rubber hardness of 30 (durometer hardness, type A). As the second endless belt 35, a belt having a polysiloxane carrier having a thickness of 350 μm and a rubber hardness of 30 (durometer hardness, type A) formed using silicone rubber on a PET belt base material is used. did. The same solvent absorber and polysiloxane carrier as those used in Example 1 were used.

In addition, the same silicone blanket 11, blower 17, low molecular weight polysiloxane compound, printing pattern, intaglio, ink, and printed material as those in Example 1 were used, and printing processing conditions, solvent absorption processing, and polysiloxane were used. The conditions for executing the supply process were set in the same manner as in Example 1.
Comparative Example 1
As the printing apparatus, the printing apparatus 10 shown in FIG. 1 was used to perform fine pattern printing. Although the printing process conditions were set in the same manner as in Example 1, the solvent absorption process and the polysiloxane supply process were not executed.

<Characteristic evaluation>
In Examples 1 and 2, even when a fine pattern was printed by continuous printing on 1000 sheets to be printed, neither a change in the line width of the print pattern nor a phenomenon of piling was observed. On the other hand, in Comparative Example 1, by continuously performing the fine pattern printing on the printing medium, an increase in the line width of the printing pattern, disorder of the printed shape of the pattern, and occurrence of piling are remarkably observed. It was.

FIG. 4 is a graph showing the relationship between the number of printed sheets and the line width of the printed pattern for Example 1 and Comparative Example 1.
As shown in FIG. 4, in Example 1 in which the solvent absorption process and the polysiloxane supply process were performed, the line width of the print pattern at the start of printing was 80 μm, which was slightly smaller than the line width (90 μm) of the intaglio plate. However, by repeating printing about 10 sheets, the line width of the print pattern was stabilized at about 90 μm. Note that the line width reference value of the print pattern for determining the execution of the solvent absorption process is 90 μm.

  The variation in the line width of the printed pattern is acceptable within ± 9 μm (within ± 10% with respect to the reference value) when used as an electrode pattern for PDP. Even after printing was repeated, a more preferable range of variation (within ± 4.5 μm; within ± 5% of the reference value) was satisfied. In addition, the printed shape was satisfactory because the printed pattern was not disturbed, whiskers, or protrusions.

On the other hand, in Comparative Example 1 in which the solvent absorption process and the polysiloxane supply process were not executed, the line width of the printed pattern tended to increase as the number of printed sheets increased, and was not stable. In addition, as the number of printed sheets increased, the printed pattern was disturbed, a lot of whiskers, and protrusions were generated, which was not suitable for practical use.
The present invention is not limited to the above description, and various design changes can be made within the scope of the matters described in the claims.

1 is a block diagram illustrating a configuration of a printing apparatus according to an embodiment of the present invention. It is a block diagram which shows the structure of the printing apparatus which concerns on the example of design change of FIG. It is a block diagram which shows the structure of the printing apparatus which concerns on other embodiment of this invention. In Example 1 and Comparative Example 1, it is a graph which shows the relationship between the number of printed sheets and the line width of a pattern.

Explanation of symbols

10, 10 'printing device 11 silicone blanket 12 blanket cylinder 13, 13' endless belt 14 first region 15 second region 16, 16a, 16b pulley 17 blower 18 polysiloxane applicator 20, 21 control unit 30 printing device 33 first 1 endless belt 34, 34a, 34b pulley 35 second endless belt 36, 36a, 36b pulley

Claims (5)

A silicone blanket fixed to the outer peripheral surface of the rotatable blanket cylinder ;
An endless belt in contact with the silicone blanket ;
It is arranged in a ring of the endless belt, the endless belt is arranged so as to be separated from and contactable with the silicone blanket, and the endless belt is driven to circulate with respect to the silicone blanket. A plurality of pulleys for movement,
The endless belt is partitioned into two regions, a first region formed by a solvent absorber and a second region formed by a polysiloxane support, and when the endless belt comes into contact with the silicone blanket, a solvent absorbing means for absorbing the solvent of the ink contained in the silicone blanket, characterized that you have both the means of both the polysiloxane supply means for supplying a low molecular weight polysiloxane to the silicone blanket, Printing device.   The two pulleys move relative to the nip portion so that the endless belt can move along the rotational direction of the silicone blanket at the nip portion where the endless belt and the silicone blanket are in contact with each other. The printing apparatus according to claim 1, wherein the printing apparatus is disposed on an upstream side and a downstream side of the blanket in the rotation direction.   The printing apparatus according to claim 1, further comprising a roller disposed outside the endless belt ring and in contact with the endless belt from outside the endless belt ring. Comprising a drying means for drying the endless belt, and a polysiloxane providing means for including a low molecular weight polysiloxane compound to said endless belt,
The drying means dries the contact member in the first region,
The polysiloxane applying means, in the second region, characterized in that the inclusion of low molecular weight polysiloxane compound to said endless belt, printing apparatus according to any one of claims 1 to 3. The said 1st area | region has a surface layer containing the surface which contacts the said silicone blanket, and the said surface layer consists of the rubber | gum which does not contain a plasticizer and an anti-aging agent, The 1st ~ characterized by the above-mentioned. 5. The printing apparatus according to any one of 4.

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