JP2003103210A - Coating apparatus and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating apparatus and a coating method capable of preventing coating failure in a layer to be layered on an underlayer even if coating failure takes place in the underlayer. SOLUTION: The coating apparatus is a coating apparatus for forming a plurality of layers on a continuously running belt-like substrate and comprises an upstream side coating means for forming an underlayer by applying the first coating liquid, a downstream side coating means which is positioned in the downstream side of the upstream side coating means in the running direction of the substrate and forms an upper layer on the underlayer by applying another coating liquid with similar or dissimilar composition to that of the first coating liquid, and an undercoating liquid supply means for supplying an undercoating liquid to a non-coating part, where the first coating liquid is not applied, before the non-coating part reaches the downstream side coating means in the case the non-coating part is generated at the time of forming the underlayer. The coating method is carried out by employing the apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus and a coating method, and in particular, it is stable for a long time when a plurality of layers are formed by sequentially coating two or more coating solutions on a long strip-shaped substrate. It is an object of the present invention to provide a coating device and a coating method capable of continuously coating the same.

[0002]

2. Description of the Related Art A lithographic printing plate is usually a continuous strip-shaped aluminum thin plate, and one or both surfaces of an aluminum web is grained according to a conventional method to produce a support web, and the support web is grained. After the anodic oxide film is formed on the surface, a plate-making layer which is a single layer or a multilayer photosensitive layer or a heat-sensitive layer is formed, and an antioxidant layer is formed on the surface of the plate-making layer.

In a lithographic printing plate having multiple plate-making layers or a lithographic printing plate having an antioxidant layer on the plate-making layer, it is general to form each layer one by one. The layer is usually coated with a coating liquid such as a photosensitive layer forming liquid containing a photosensitive resin, a heat sensitive layer forming liquid containing a thermopolymerizable resin, and an antioxidant layer forming liquid containing a polyvinyl alcohol aqueous solution as a main component. , And then dried.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When the photosensitive layer forming liquid is applied and then dried to form a photosensitive layer, and then the antioxidant layer forming liquid is applied on the photosensitive layer and dried to form the antioxidant layer, the photosensitive layer forming liquid is used. When an uncoated portion where is not applied occurs for some reason, the anodized layer of the support web is exposed in the uncoated portion.

The anti-oxidation layer forming solution wets the photosensitive layer well, but does not necessarily wet the anodized film.

Nevertheless, In the conventional coating layer, the coating of the antioxidant layer forming liquid is continued as it is even if the uncoated portion is generated, so that the coating failure of the antioxidant layer forming liquid occurs in the uncoated portion and the antioxidant layer is formed. There is a problem that the forming liquid cannot be applied uniformly. And
Once the coating failure of the antioxidant layer forming liquid occurs, the coating failure of the photosensitive layer forming liquid is corrected, and even when the photosensitive layer forming liquid is normally coated, the coating of the antioxidant layer forming liquid is performed. There was a problem that defects could not be resolved.

An object of the present invention is to provide a coating apparatus and a coating method in which even if a coating failure occurs in the lower layer, the coating failure does not occur in the upper layer laminated on the lower layer. .

[0008]

According to a first aspect of the present invention, there is provided a coating apparatus for forming a plurality of layers on a continuously running strip-shaped substrate, wherein one coating solution is applied to form a lower layer. And an upstream coating means that is located downstream of the upstream coating means with respect to the traveling direction of the base material, and another coating solution having the same or different composition as the one coating solution on the lower layer. And a downstream-side coating means for forming an upper layer by applying a coating solution and an uncoated portion where the one coating solution is not applied during the formation of the lower layer, before the uncoated portion reaches the downstream-side coating means. In addition, the present invention relates to a coating device comprising: an undercoating liquid applying means for applying an undercoating liquid to the uncoated portion.

In the coating apparatus, when a coating failure occurs in the lower layer forming means and an uncoated portion occurs, the undercoat liquid coating means coats the undercoat liquid on the uncoated portion. Next, the uncoated portion passes through the downstream coating means, but since the undercoat liquid has already been coated on the uncoated portion, the other coating liquid adheres well.

Therefore, in the coating apparatus, even if a coating failure occurs in the upstream coating means and a non-coating portion occurs, when the other coating liquid is coated on the lower layer, No defective coating caused by the coated portion will occur.

The base material is not particularly limited as long as it is a strip-shaped and flexible thin plate-shaped or film-shaped article, and specifically, for the support web, photographic film and motion picture film. Film base for photographic recording materials such as photographic recording materials, baryta paper for photographic paper, recording tape, video tapes, base materials for magnetic recording materials such as polyester films used for magnetic recording materials such as floppy (R) disks, and color iron plates Examples include thin metal plates for coated metal plates. The substrate may be subjected to various treatments such as graining and anodizing treatment of the support web.

The lower layer may be directly formed on the base material, or may be a layer laminated on another layer formed on the base material.

Examples of the one coating solution and the other coating solution include, for example, the photosensitive layer forming liquid, the heat sensitive layer forming liquid, and the antioxidant layer forming liquid described in the section of "Prior Art", and the photographic recording material. Emulsion used for forming a photosensitive layer of a photographic paper, an antihalation layer forming liquid used for forming an antihalation layer of the photographic recording material, and magnetic recording forming a magnetic recording layer of the magnetic recording material. Examples of the layer forming liquid include various paints used for undercoating, intermediate coating, and topcoating of the coated metal plate, and any solution or suspension capable of forming a layer by coating on the substrate and drying. However, it is not limited to the above.

The above-mentioned one coating solution and the other coating solution may have the same composition or different compositions.

As the upstream coating means, a coating device which is usually used for coating the solution or suspension mentioned as the one coating solution on the substrate can be used.

As such a coating apparatus, in addition to a bar coater for coating with a grooved bar having a circumferential groove formed on the surface and a coating bar such as a wire bar wound with a fine metal wire, the surface is smooth. A non-contact coating device such as a rod coater, a slide bead coater, a curtain coater, and an extrusion coater that coats with a coating rod can be used to coat the coating liquid without contacting the substrate.

As the downstream coating means, the various coating devices described in the upstream coating means can be used, but the non-contact coating device is preferable because it does not damage the lower layer.

Examples of the undercoating liquid applied by the undercoating liquid applying means include liquids for improving the wettability between the base material and the other coating liquid.

When the undercoating liquid has a surface tension equal to or higher than the surface tension of the other coating liquid, when the undercoating liquid is applied and then the other coating liquid is applied. It is preferable because coating defects such as streaks and running out of liquid do not occur.

As the undercoat liquid, as will be described later,
A liquid containing the main solvent of the other coating liquid as a main component can be used, and a surfactant solution can also be used. The solvent of the surfactant solution is preferably the main solvent of the other coating solution. Especially when the main solvent of the other coating liquid is water,
It is preferable to use an aqueous solution containing a surfactant as the undercoat liquid, because the pre-wet portion uniformly spreads over the uncoated portion. The concentration of the surface active agent in the surfactant solution is preferably a micelle concentration or higher. When the other coating liquid contains a surfactant, it is preferable that the undercoat liquid also contains the same surfactant.

The amount of the undercoating liquid applied by the undercoating liquid applying means can be determined according to the width of the substrate and the composition of the undercoating liquid.
and the cc / m ² or more, in the case of organic solvent-based 2 cc / m ²
This is preferable because the undercoat liquid can be attached to the entire surface of the base material.

The application of the undercoat liquid means that the above-mentioned undercoat liquid is attached to the coated surface of the above-mentioned base material by any method, and specifically, the above-mentioned undercoat liquid is applied, and dropping, spraying from a syringe or the like is performed. Can be mentioned.

Examples of the undercoating liquid applying means include an undercoating liquid applying device for applying the undercoating liquid to the base material.

As the undercoating liquid application device, an undercoating liquid application head for extruding and applying the undercoating liquid in a band shape toward the base material, and a grooved bar or a thin metal wire having a circumferential groove formed on the surface thereof are wound. A coating bar such as a wire bar may be used.

As the undercoat liquid coating head, a slide bead type coater having the same configuration as the slide bead coater, a curtain type coater having the same configuration as the curtain coater, and the same configuration as the extrusion type coater are used. The extrusion type coater which it has is mentioned.

Other means for applying the undercoat liquid include:
An undercoating liquid injector for depositing the undercoating liquid in the form of drops on the surface of the base material may also be used.

The invention as set forth in claim 2 relates to a coating device in which the undercoat liquid applying means stops the application of the undercoat liquid when the uncoated portion disappears.

In the coating apparatus, the application of the undercoating liquid is stopped when it is no longer necessary to apply the undercoating liquid to the lower layer, so that the undercoating liquid is not wasted. Further, there is no problem that the other coating liquid is diluted with the undercoating liquid and it takes time to dry after coating.

According to a third aspect of the present invention, the upstream coating means is formed so as to separate from the coating surface of the base material when the uncoated portion occurs, and the undercoat liquid applying means is the above-mentioned. The present invention relates to a coating device that applies the undercoat liquid when the upstream coating means separates from the base material.

Also in the conventional coating apparatus, when a coating failure occurs in the upstream coating means during formation of the lower layer,
In order to facilitate recovery, the upstream coating means is formed so as to be separated from the coating surface of the base material.

In the above coating apparatus, since the undercoating liquid applying means is activated by utilizing the detachment of the upstream side coating means, the components of the conventional coating apparatus can be used almost as they are. There is no need to separately provide an uncoated portion detection device that detects the occurrence of an uncoated portion and activates the undercoat liquid applying means.

According to a fourth aspect of the present invention, there is provided uncoated portion detecting means for detecting the occurrence of an uncoated portion when the lower layer is formed, and the undercoat liquid applying means is the uncoated portion detecting means. Relates to a coating device that applies an undercoat liquid to the uncoated portion when the occurrence of the uncoated portion is detected.

In the coating device, regardless of whether or not the upstream coating means separates from the coating surface,
Since the undercoat liquid applying means can be activated by detecting the occurrence of the uncoated portion, the effect of the present invention is more reliably exhibited.

Examples of the uncoated portion detecting means include an optical uncoated portion detecting device which optically detects the occurrence of an uncoated portion.

The invention according to claim 5 relates to a coating apparatus in which the downstream coating means is a non-contact coating means for coating the other coating liquid on the lower layer in a non-contact manner.

The coating apparatus is characterized in that the lower layer is not damaged during the coating of the other coating liquid by the downstream coating means.

Examples of the non-contact coating means include a slide bead coater, a curtain coater, an extrusion coater, and the like, and the rod coater described in the upstream coating means and the like are also included, but any of them can be used. The coating device is not limited to the slide coater as long as it is a coating device that can coat the other coating liquid without contacting the lower layer.

According to a sixth aspect of the present invention, the non-contact coating means discharges the other coating liquid in a strip shape, and a slide surface on which the other coating liquid discharged from the discharge slit flows down. And a tip of the slide surface is located in the vicinity of a running surface that is a running path of the base material, and a coating liquid is provided between the tip of the sliding surface and the lower layer formed on the base material. The present invention relates to a coating device that is a slide bead coater that forms crosslinks and coats the other coating liquid on the lower layer.

The coating apparatus is an example of the coating apparatus according to claim 5, wherein a slide bead coater is used as the non-contact coating means.

According to a seventh aspect of the present invention, the non-contact coating means is disposed above the traveling surface, and the other coating liquid is curtain-shaped on the lower layer formed on the base material. The present invention relates to a coating device that is a curtain coater that coats by flowing down.

The coating apparatus is an example of the coating apparatus according to claim 5, wherein a curtain coater is used as the non-contact coating means.

According to an eighth aspect of the present invention, the non-contact coating means has a slit shape that opens toward the running surface and discharges the other coating liquid toward the lower layer formed on the base material. The present invention relates to a coating device which is an extrusion coater having a discharge slit.

The coating apparatus is an example of the coating apparatus according to claim 5, wherein an extrusion coater is used as the non-contact coating means.

The invention according to claim 9 relates to a coating apparatus comprising a lower layer drying means for drying the lower layer between the upstream coating means and the undercoat liquid applying means.

Examples of the lower layer drying means include a hot air drying device for blowing hot air to dry, a radiation type drying device for drying by radiation from an electric heater, and a high frequency heating device for drying by high frequency heating.

The invention described in claim 10 relates to a coating device, wherein the undercoating liquid applying means applies a liquid having a surface tension equal to or larger than the surface tension of the other coating liquid as the undercoating liquid.

According to the coating apparatus, it is possible to effectively prevent the occurrence of coating defects such as streaks and runoff when the other coating liquid is coated by the downstream coating means.

The eleventh aspect of the present invention relates to a coating apparatus in which the undercoating liquid applying means applies, as an undercoating liquid, a liquid containing a main solvent of the other coating liquid as a main component.

Since the undercoating liquid has a high affinity for the other coating liquid, the coating device can effectively adhere the other coating liquid to the uncoated portion.

The twelfth aspect of the present invention relates to a coating apparatus, wherein the undercoat liquid applying means applies a solution containing a surfactant as the undercoat liquid.

In the coating apparatus, when water is used as the undercoating liquid, the surface tension is lowered by the surfactant, so that it spreads widely on the uncoated portion. Therefore, the other coating liquid can be effectively attached to the uncoated portion, and the object of the present invention can be reliably achieved.

The thirteenth aspect of the present invention relates to a coating apparatus in which the concentration of the surfactant in the undercoat liquid is at least the micelle concentration.

The surface tension lowering effect of the surfactant becomes particularly remarkable when the concentration of the surfactant is higher than the micelle concentration. Therefore, the effect described in claim 15 can be obtained with certainty in the coating device.

According to a fourteenth aspect of the present invention, the downstream coating means applies a coating solution containing a surfactant as another coating solution, and the undercoating liquid applying means uses the other coating solution as an undercoating solution. The present invention relates to a coating device that applies a solution containing the same surfactant as the surfactant contained in the coating liquid.

In the coating apparatus, since the surfactant contained in the undercoating liquid and the other coating liquid are the same, the surfactant in the undercoating liquid may become an impurity in the other coating liquid. Absent.

The invention described in claim 15 relates to a coating apparatus in which the substrate is a support web for a lithographic printing plate.

The coating apparatus is an example in which the coating apparatus of the present invention is applied to the production of a lithographic printing plate.

According to a sixteenth aspect of the present invention, in the coating apparatus, the upstream coating means coats a photosensitive layer forming liquid containing a photosensitive resin as the one coating liquid.

The coating apparatus is an example in which the coating apparatus of the present invention is applied to the production of a planographic printing plate having a visible light exposure type plate making layer.

The invention according to claim 17 relates to a coating apparatus in which the downstream coating means coats an antioxidant layer forming liquid containing a polyvinyl alcohol solution as a main component as the other coating liquid.

The coating apparatus is an example in which the coating apparatus of the present invention is applied to the production of a lithographic printing plate having an antioxidant layer as the uppermost layer.

The invention described in claim 18 is a coating method for forming a plurality of layers on a continuously running strip-shaped substrate, wherein one coating solution is coated to form a lower layer, and the lower layer is formed on the lower layer. When applying another coating liquid having the same or different composition as the one coating liquid to form the upper layer, if an uncoated portion in which the one coating liquid is not applied occurs when the lower layer is formed, The coating method is characterized in that the undercoating liquid is applied to the uncoated portion before the coating liquid is applied.

In the above coating method, when a coating failure occurs during formation of the lower layer and an uncoated portion is generated, the undercoat liquid is coated on the uncoated portion, and the other coating liquid is coated thereon. To be done.

Therefore, since the other coating liquid adheres well to the uncoated portion, it is effective that a coating failure due to the uncoated portion occurs when the other coating liquid is coated. To be prevented.

The base material, one coating solution, the other coating solution, and the undercoating solution are as described in claim 1.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION 1. Embodiment 1 FIG. 1 shows the configuration of an example of a coating apparatus of the present invention which forms a photosensitive layer on a support web and forms an antioxidant layer on the surface of the photosensitive layer.

The coating apparatus 100 according to the first embodiment is shown in FIG.
A bar coater 2 for forming a photosensitive layer L1 by applying a photosensitive layer forming liquid corresponding to one coating liquid of the present invention to a support web W continuously traveling in the direction a; and a bar coater. A slide bead coater 4 located on the downstream side of 2 to form an antioxidant layer L2 by applying an antioxidant layer forming liquid corresponding to another coating liquid of the present invention on the photosensitive layer L1;
Provided on the upstream side adjacent to the slide bead coater 4,
A pre-wet liquid application device 6 is provided for applying an undercoat liquid, in other words, a pre-wet liquid, to the uncoated portion when an uncoated portion occurs on the photosensitive layer L1. The bar coater 2, the slide bead coater 4, and the pre-wet liquid coating device 6 correspond to the upstream coating device, the downstream coating device, and the undercoat liquid applying device in the coating device of the present invention, respectively.

In the vicinity of the slide bead coater 4, FIG.
A backup roller 18 that rotates in the clockwise direction to convey the support web W is provided.

Bar coater 2 and pre-wet liquid coating device 6
And the photosensitive layer L formed in the bar coater 2.
1. A hot air drying type photosensitive layer drying device 8 for drying 1 is provided, and a hot air drying type antioxidant layer drying device for drying the antioxidant layer formed in the slide bead coater 4 is provided on the downstream side of the slide bead coater 4. 10 are provided.

In the vicinity of the entrance of the antioxidant layer drying device 10,
A guide roller 20 is provided to guide the carrier web W to the entrance of the antioxidant layer drying device 10.

The coating apparatus 100 is further provided with a separation signal generator 12 for generating a separation signal when the bar 2A of the bar coater 2 separates from the support web W, and a separation signal from the separation signal generator 12. And the bar 2A of the bar coater 2 is operated from the supporting body web W to measure the traveling distance of the supporting body web W. Similarly, the encoder 14 operates in response to the leaving signal from the leaving signal generating section 12. When the encoder 14 receives a signal indicating that the uncoated portion formed in the support web W has started to approach the pre-wet liquid coating device 6, the pre-wet liquid coating device 6 is coated with the pre-wet liquid. A pre-wet liquid application device control unit 16 that outputs an instruction to perform is provided.

Hereinafter, each component of the coating apparatus 100 will be described in detail.

The structure of the bar coater 2 is shown in FIG.

As shown in FIG. 2, the bar coater 2 is in contact with the roughened surface W2 of the support web W and is in the same direction as the running direction a of the support web W as indicated by an arrow b in FIG. A bar 2A rotating in a vertical direction, a bar supporting member 2B that is a plate-shaped member that supports the bar 2A from below by a V-shaped groove formed on the top surface, and is erected on the upstream side of the bar supporting member 2B. The upstream weir plate 2C extending in the vertical direction toward the traveling surface T that is the traveling path of the support web W, and the traveling path that is the traveling path of the support web W that is erected on the downstream side of the bar support member 2A. It includes a downstream dam plate 2D extending in the vertical direction toward the surface T, a bar support member 2B, an upstream dam plate 2C, and a base 2E to which the downstream dam plate 2D is fixed.

Between the bar support member 2B and the upstream dam plate 2C, an upstream liquid supply flow path 2F for supplying a photosensitive layer forming liquid to the upstream side of the bar 2A is provided, and the bar support member 2B and the downstream side. A downstream side liquid supply flow path 2G for supplying the photosensitive layer forming liquid is provided downstream of the bar 2A between the barrier plate 2D. The upstream liquid supply passage 2F and the downstream liquid supply passage 2G communicate with each other through a communication passage 2H provided in a lower portion of the bar support member 2B.

A liquid supply conduit 2J for supplying the photosensitive layer forming liquid is connected to the lower end of the upstream liquid supply passage 2F.

Above the traveling surface T, there is provided a pair of web pressing rollers 2K which press the support web W toward the bar 2A while being driven and rotated around the axis when the photosensitive layer forming liquid is applied. It is arranged.

Below the base 2E, an elevating device 2L for elevating the base 2E is provided. The elevating device 2L lowers the base 2E to lower the bar 2E when a coating failure occurs in the bar coater 2 and an uncoated portion occurs on the support web W.
It has a function of separating A from the support web W and, at the same time, outputting a signal indicating that the base 2E has been lowered to the separation signal generator 12. When the detachment signal generator 12 receives the signal from the lifting device 2L, the detachment signal generator 12 generates a detachment signal and outputs it to the encoder 14 and the pre-wet liquid application device controller 16. A state in which the base 2E is lowered and the bar 2A is separated from the support web W is shown by a chain double-dashed line in FIG.

As the elevating device 2L, a ball screw type elevating device for elevating the base 2E with a ball screw, a hydraulic cylinder type elevating device elevating with a hydraulic cylinder, and a pneumatic cylinder type elevating device elevating with a pneumatic cylinder are used. Can be mentioned.

Examples of the bar 2A include a grooved bar in which circumferential grooves are provided at regular intervals or densely provided, and a wire bar in which a thin metal wire is wound around the surface.

At the time of applying the photosensitive layer forming liquid, the bar 2
A abuts the carrier web W in the part between the grooves formed in the surface or in the part of the wire wound on the surface,
A flow path of the photosensitive layer forming liquid is formed between the concave portions between the grooves or the wire bars and the support web W, and the photosensitive layer forming liquid is applied in a predetermined thickness.

Next, FIG. 3 shows the slide bead coater 4 and its vicinity.

As shown in FIG. 3, the slide bead coater 4 is provided with a slide bead coater main body 4A which is formed in a substantially rectangular parallelepiped block shape.

The slide bead coater main body 4A has a tip portion 4B protruding in a wedge shape toward the backup roller 18 and having an edge parallel to the surface of the backup roller 18. The tip portion 4B is wound around the above-mentioned edge and the backup roller 18 so that the slide bead coater 4
Between the support web W passing in the vicinity and usually about 0.1
Although it is formed so that a gap of about 1 mm is formed, the size of the gap can be determined according to the thickness of the antioxidant layer L2 to be formed on the support web W.

On the upper surface of the slide bead coater main body 4A, there is formed a slide surface 4C which is inclined downward toward the edge of the tip portion 4B. A discharge slit 4D, which is a slit-shaped channel through which the antioxidant layer forming liquid is discharged, is provided from the inside of the slide bead coater main body 4A toward the slide surface 4C. The discharge slit 4D opens in a slit shape along the width direction of the traveling surface T in the middle of the slide surface 4C, and at the lower end, the discharge slit 4D.
D is connected to the liquid supply channel 4E for supplying the antioxidant layer forming liquid.

Below the tip portion 4B, a decompression chamber 4F is provided.
Is provided, and a decompression pipe 4G for decompressing the inside is connected to the bottom of the decompression chamber 4F. Inside the decompression chamber 4F, there is provided a gutter-shaped excess liquid receiver 4H for receiving the excess amount of the antioxidant layer forming liquid discharged from the discharge slit 4D that is not applied to the support web W. A drainage pipe 4J for leading out the excess antioxidant layer forming liquid to the outside extends downward from 4H. A drainage storage tank 4K is provided at the lower end of the drainage pipe 4J to store the antioxidant layer forming liquid discharged through the drainage pipe 4J. A pressure reducing pipe 4L for reducing the pressure inside is also connected to the drainage storage tank 4K.

When the anti-oxidation layer forming liquid is applied to the support web W, the inside of the decompression chamber 4F is controlled by a vacuum pump or an aspirator connected to the decompression pipe 4G.
For example, the pressure is reduced to about 0.5 to 10 cm of water column. Further, the inside of the drainage storage tank 4K is also depressurized to the same level as the inside of the depressurization chamber 4F through the depressurization pipe 4L.

In this state, the antioxidant layer forming liquid is discharged from the discharge slit 4D to make the slide surface 4C flow down toward the edge of the tip 4B, and the edge of the tip 4B,
An application bead is formed between the support web W and the photosensitive layer L1 to apply an antioxidant layer forming liquid to form an antioxidant layer L2.
To form.

The structure of the pre-wet liquid coating device 6 is shown in FIG.

As shown in FIG. 4, the pre-wetting liquid coating device 6 is provided with a coating head 6A formed in a wedge shape that contracts upward, along the width direction of the traveling surface T. Inside the coating head 6A, a pre-wet liquid discharge channel 6B is formed which is opened at the upper end in a slit shape along the longitudinal direction of the coating head 6A. Coating head 6
A is fixed on a lift table 6C that moves up and down by a hydraulic cylinder. The lift table 6C may be lifted by a pneumatic cylinder or may be lifted by a ball screw.

The pre-wet liquid discharge flow channel 6B is in communication with the liquid supply flow channel 6D for supplying the pre-wet liquid to the pre-wet liquid discharge flow channel 6 at the lower end. The liquid supply channel 6D is
It is connected to the pre-wet liquid storage tank 6F via the liquid supply pipe 6E. A liquid feed pump P that feeds the pre-wet liquid toward the pre-wet liquid discharge channel 6B is interposed in the liquid supply pipe 6E. Instead of the liquid feed pump P, a liquid feed bellows that feeds the pre-wet liquid may be used.

The lift table 6C and the liquid feed pump P are controlled by the prewetting liquid application device control unit 16. When the pre-wet liquid application device control unit 16 outputs an instruction to start the application of the pre-wet liquid, the elevating table 6C moves to the position shown in FIG.
At the coating head 6A.
The upper end opening of is close to the support web W. Next, the liquid feed pump P is operated, the pre-wet liquid stored in the pre-wet liquid storage tank 6F is supplied to the coating head 6A, and is discharged upward from the upper end opening of the pre-wet liquid discharge flow channel 6B to support it. Applied to the body web W. When the pre-wet liquid application device controller 16 outputs an instruction to stop the application of the pre-wet liquid, first, the liquid feed pump P is stopped and the pre-wet liquid is discharged from the upper end opening of the pre-wet liquid discharge flow path 6B. Wetting liquid stops discharging. Then, the elevating table 6C descends, and the coating head 6A returns to the position shown by the solid line in FIG.

The operation of the coating apparatus 100 will be described below.

FIG. 5 shows the operation flow when the coating failure occurs in the bar coater 2.

As shown in FIG. 5, when a coating failure occurs in the bar coater 2 and an uncoated portion occurs on the graining surface W2 of the support web W, the lifting device 2L descends the base 2E as described above. Then, the bar 2A is separated from the support web W, and at the same time, an instruction to generate a separation signal indicating that the bar coater has separated is output to the separation signal generator 12.

In response to the instruction, the separation signal generator 12 generates a separation signal and outputs it to the encoder 14 and the pre-wet liquid coating device controller 16.

The pre-wetting liquid application device control unit 16 is automatically activated upon receiving the withdrawal signal, and is ready to receive the signal from the encoder 14.

On the other hand, when the encoder 14 receives the detachment signal, the encoder 14 measures the traveling distance d of the support web W after the bar 2A of the bar coater 2 is detached, and measures the distance L from the bar 2A to the coating head 6A. The traveling distance d is compared. Then, when d becomes L-ΔL or more, a signal to that effect is output to the prewetting liquid application device control unit 16. Here, ΔL is a length that is much smaller than L, and it depends on the traveling speed of the support web W, the response speed of the prewetting liquid coating device 6 to the instruction from the prewetting liquid coating device control unit 16, and the like. It can be set arbitrarily. Then, when the traveling distance d becomes equal to L-ΔL, the uncoated portion is close to the coating head 6A.

When the prewetting liquid coating device control unit 16 receives a signal from the encoder 14 that the running distance d has become equal to L-ΔL, the prewetting liquid coating device 6 is coated with the prewetting liquid. Outputs an instruction to the effect.

When the pre-wet liquid coating device 6 receives the instruction, the lifting head 6C raises the coating head 6A,
It is close to the graining surface W2 of the support web W. And
The liquid feed pump P is activated to discharge the pre-wetting liquid from the top of the coating head upward, and the prewetting liquid W is coated on the grained surface W2.

On the other hand, when the coating failure is eliminated in the bar coater 2, the base 2E is raised and the bar 2A is brought into contact with the support web W, and the coating of the photosensitive forming liquid is restarted, a signal to that effect is given. It is transmitted to the encoder 14 and the pre-wet liquid application device control unit 16 via the detachment signal generation unit 12.

When the encoder 14 receives the signal, the encoder 14 again measures the traveling distance of the support web W, and when the traveling distance d'after receiving the signal becomes L,
A signal indicating that the traveling distance d ′ = L is output to the pre-wetting liquid application device control unit 16. Upon receiving the signal, the pre-wet liquid application device control unit 16 outputs a signal to the pre-wet liquid application device 6 to the effect that the application of the pre-wet liquid should be stopped. Pre-wet liquid coating device 6
When receiving the signal, the procedure is the reverse of that at the start of coating,
Stop applying the pre-wet liquid.

If a coating failure occurs during the formation of the photosensitive layer L1 by coating the support web W with the photosensitive layer forming liquid, an uncoated portion is formed on the support web W and the anodized film is exposed. . As described above, since the anti-oxidation layer forming liquid does not wet the anodized film, when the pre-wetting liquid is not applied, as shown in FIG. Even if the coating liquid is repelled and the coating failure in the photosensitive layer forming layer L1 is eliminated, a uniform film of the antioxidant layer forming liquid cannot be obtained.

On the other hand, in the coating apparatus 100 according to the first embodiment, by applying the pre-wetting liquid, as shown in FIG. 6A, the antioxidant layer L2 is also applied to the uncoated portion. Is formed without interruption, and the coating failure in the photosensitive layer forming layer L1 is eliminated,
Again, a film having a two-layer structure composed of the photosensitive layer L1 and the antioxidant layer L2 is stably formed.

Therefore, in the coating apparatus 100,
Even if an uncoated portion occurs in the photosensitive layer L1, formation failure or uncoated portion does not occur in the antioxidant layer L2 laminated thereon.

Further, in the coating apparatus 100, the pre-wet liquid coating apparatus 6 is activated by using the separation signal indicating that the bar coater 2 has separated from the coating position.
It is not necessary to provide an uncoated portion detection device that detects the occurrence of an uncoated portion in the photosensitive layer L1.

Since the grained surface of the support web W is a rough surface and an anodic oxide coating is formed on the surface,
Not only the antioxidant layer forming liquid but also the photosensitive layer forming liquid does not easily adhere, but in the coating apparatus 100, since the bar coater is used for coating the photosensitive layer forming liquid, defective coating and uneven coating are less likely to occur. Another advantage is that it is easy to form a uniform photosensitive layer.

2. Embodiment 2 FIG. 7 shows the configuration of another example of the coating apparatus of the present invention, in which a photosensitive layer is formed on a support web and an antioxidant layer is formed on the surface of the photosensitive layer. 7, the same reference numerals as those in FIG. 1 denote the same constituent elements as those shown in FIG.

As shown in FIG. 7, in the coating apparatus 102 according to the second embodiment, uncoated in the vicinity of the coating head 6A between the photosensitive layer drying apparatus 8 and the coating head 6A in the pre-wet liquid coating apparatus 6. An uncoated portion detection device 30 that optically detects the occurrence of a portion is provided.

The uncoated portion detection device 30 is connected to the pre-wet liquid coating device control unit 16 and, upon detecting the occurrence of the uncoated portion, outputs a signal to that effect to the pre-wet liquid coating device control unit 16. To do.

As the uncoated portion detecting device 30, for example, a light emitting / receiving element in which a light emitting element such as a light emitting diode and a light receiving element such as a photodiode and a phototransistor are integrated can be used. The light emitting element is preferably one that emits red light or infrared light.

The coating apparatus 102 has the same structure as the coating apparatus 100 according to the first embodiment, except for the above points and the point that the separation signal generator 12 and the encoder 14 are not provided.

The operation of the coating device 102 will be described below.

The photosensitive layer forming liquid applied by the bar coater 2 is usually mixed with various pigments or dyes in addition to the photosensitive resin, and is colored dark green to dark blue. Therefore, the photosensitive layer L1 formed by applying the photosensitive layer forming liquid
Also has a similar color.

Therefore, the photosensitive layer L is formed on the support web W.
While 1 is uniformly formed, the uncoated portion detection device 30
The light radiated from the light emitting element toward the photosensitive layer L1 is almost entirely absorbed in the photosensitive layer L1, and almost no light is reflected toward the light receiving element of the uncoated portion detection device 30.

However, when a coating failure occurs in the bar coater 2 and an uncoated portion is formed on the photosensitive layer L1, the metal surface of the support web is exposed, so that the light from the light emitting element in the uncoated portion detection device 30 is The light is reflected by the uncoated portion and is incident on the light receiving element. In the uncoated portion detection device 30,
The uncoated portion can be detected by detecting the incident light.

When the uncoated portion detecting device 30 detects the uncoated portion on the support web W as described above, it sends a signal to that effect to the prewetting liquid coating device control unit 16 to apply the prewetting liquid coating. The device control unit 16 activates the pre-wetting liquid application device 6 in the procedure described in the first embodiment. Then, the pre-wetting liquid is applied by the application head 6A.

The coating device 102 has the features of the coating device 100 of the first embodiment, as well as the pre-wetting liquid coating device 6
Since the uncoated portion is optically detected on the upstream side in the vicinity of, there is a feature that the uncoated portion can be detected and the pre-wet liquid can be applied more reliably.

Further, the coating device 102 has an advantage that the constitution can be simplified because the disengagement signal generator 12 and the encoder 14 can be omitted.

[0120]

EXAMPLES The present invention will be described in more detail with reference to examples.

(Example 1) Using the coating apparatus shown in FIG.
The photosensitive layer forming liquid was applied on the support web W to form a photosensitive layer, and the antioxidant layer forming liquid was applied on the photosensitive layer to form an antioxidant layer. Table 1 shows the composition of the photosensitive layer forming liquid, the antioxidant layer forming liquid, and the pre-wet liquid described later.

[0122]

[Table 1] In the coating apparatus 100, when a coating failure occurs on the bar coater 2 and an uncoated portion occurs on the surface of the support web W, the bar 2A separates from the coating surface of the support web W, and as described in the first embodiment. In accordance with the procedure, the separation signal generator 12, the encoder 14, and the pre-wet liquid application device controller 1
6 worked. Then, in the pre-wetting liquid application device 6, the pre-wetting liquid was applied to the uncoated portion.

Therefore, on the surface coated with the antioxidation layer forming liquid, the uniform antioxidation layer L2 could be formed without generating any uncoated portion.

COMPARATIVE EXAMPLE 1 A coating apparatus having the same structure as the coating apparatus 100, except that the pre-wet liquid coating apparatus controller 16 and the pre-wet liquid coating apparatus 6 are not used, and the photosensitive layers shown in Table 1 above are used. The forming liquid and the antioxidant layer forming liquid were applied.

When a coating failure occurs on the bar coater 2 and an uncoated portion occurs on the photosensitive layer L1, a coating failure such as a streak or liquid shortage occurs on the coating surface coated with the antioxidant layer forming liquid, and the uncoated portion is left uncoated. Been formed. The defective coating does not disappear even after the defective coating in the bar coater 2 is resolved.
No uniform antioxidant layer was obtained.

[0126]

As described above, according to the present invention,
Provided is a coating apparatus and a coating method in which even if a coating failure occurs in the lower layer, the coating failure does not occur in the upper layer laminated on the lower layer.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an example of a coating apparatus which is a coating apparatus of the present invention and which forms a photosensitive layer on a support web and forms an antioxidant layer on the surface of the photosensitive layer. is there.

FIG. 2 is a partially enlarged view showing the structure of a bar coater included in the coating device shown in FIG.

FIG. 3 is a partially enlarged view showing a slide bead coater provided in the coating apparatus shown in FIG. 1 and its vicinity.

FIG. 4 is a partially enlarged view showing a configuration of a pre-wet liquid coating apparatus included in the coating apparatus shown in FIG.

5 is a flowchart showing a flow of operations of the coating apparatus shown in FIG. 1 when a coating failure occurs in the bar coater.

FIG. 6 is a diagram showing the coating apparatus shown in FIG. 1 in which, when a photosensitive layer and an antioxidant layer are formed on a support web, oxidation is prevented when an uncoated portion is formed on the photosensitive layer. It is sectional drawing which shows the formation state of a layer about the case where a pre-wet liquid is applied, and the case where it is not applied.

FIG. 7 is a schematic diagram showing the configuration of another example of the coating apparatus, which is the coating apparatus of the present invention, in which a photosensitive layer is formed on a support web and an antioxidant layer is formed on the surface of the photosensitive layer. It is a figure.

[Explanation of symbols]

2 bar coater 2A bar 2L lifting device 4 slide bead coater 6 Pre-wet liquid coating device 6A coating head 6B Pre-wet liquid discharge channel 6C lift 8 Photosensitive layer dryer 12 Departure signal generator 14 encoder 16 Pre-wet liquid coating device controller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03F 7/11 501 501 G03F 7/11 501 7/16 501 7/16 501 F term (reference) 2H025 AB03 CC04 DA03 EA04 2H096 AA07 BA20 CA13 CA20 4D075 AC04 AC14 AC91 AE03 CA47 CA50 DA04 DB07 DC24 DC27 EA07 EA45 EB19 EC35 4F041 AA12 AB02 CA04 CA07 CA12 4F042 AA22 AB00 CB02 CB18 DF15

Claims (18)

[Claims] 1. A coating device for forming a plurality of layers on a continuously running strip-shaped base material, comprising: an upstream coating means for applying one coating solution to form a lower layer; and a running direction of the base material. And a downstream coating means that is located on the downstream side of the upstream coating means and that coats another coating liquid having the same or different composition as the one coating liquid on the lower layer to form an upper layer. In the formation of the lower layer, if an uncoated portion where the one coating liquid is not applied is generated, an undercoat that applies an undercoat liquid to the uncoated portion before the uncoated portion reaches the downstream coating means. A coating device comprising a liquid applying means. 2. The undercoat liquid application means stops application of the undercoat liquid when the uncoated portion disappears.
The coating device according to 1. 3. The upstream coating means is formed so as to separate from the coating surface of the base material when the uncoated portion is generated, and the undercoat liquid applying means is such that the upstream coating means is the base. The coating device according to claim 1, wherein the undercoat liquid is applied when the material is separated from the surface of the material. 4. An uncoated portion detecting means for detecting the occurrence of the uncoated portion at the time of forming the lower layer is provided, wherein the undercoat liquid applying means has the uncoated portion detecting means to generate an uncoated portion. The coating device according to any one of claims 1 to 3, wherein the undercoat liquid is applied to the uncoated portion when detected. 5. The coating apparatus according to claim 1, wherein the downstream coating means is a non-contact coating means that applies the other coating liquid to the lower layer in a non-contact manner. 6. The non-contact coating means comprises a discharge slit for discharging the other coating liquid in a band shape, and a slide surface on which the other coating liquid discharged from the discharge slit flows down. Of the lower layer is formed in the vicinity of a traveling surface that is a traveling path of the base material, and a coating solution bridge is formed between the tip of the sliding surface and the lower layer formed on the base material. The coating device according to claim 5, which is a slide bead coater that coats the other coating liquid on the substrate. 7. The curtain coater, wherein the non-contact coating means is disposed above the traveling surface, and applies the other coating liquid by flowing it down in a curtain shape to the lower layer formed on the base material. The coating apparatus according to claim 5, wherein 8. The extrusion which has a slit-shaped discharge slit which opens toward the running surface and discharges the other coating liquid toward the lower layer formed on the base material. The coating apparatus according to claim 5, which is a coater. 9. The coating apparatus according to claim 1, further comprising a lower layer drying unit that dries the lower layer between the upstream coating unit and the undercoat liquid applying unit. 10. The undercoating liquid applying means applies a liquid having a surface tension equal to or larger than the surface tension of the other coating liquid as the undercoating liquid. The coating device described. 11. The coating apparatus according to claim 1, wherein the undercoating liquid applying means applies a liquid containing a main solvent of the other coating liquid as a main component as the undercoating liquid. 12. The undercoat liquid applying means applies a solution containing a surfactant as the undercoat liquid.
11. The coating apparatus according to any one of 11 above. 13. The coating apparatus according to claim 12, wherein the concentration of the surfactant in the undercoat liquid is not less than the micelle concentration. 14. The downstream coating means applies a coating solution containing a surfactant as another coating solution, and the undercoating liquid applying means serves as an undercoating solution containing a surface active agent contained in the other coating solution. The coating apparatus according to claim 12 or 13, wherein a solution containing the same surfactant as the agent is applied. 15. The coating apparatus according to claim 1, wherein the substrate is a support web for a lithographic printing plate. 16. The coating apparatus according to claim 15, wherein the upstream coating means coats a photosensitive layer forming liquid containing a photosensitive resin as the one coating liquid. 17. The coating apparatus according to claim 15, wherein the downstream coating means coats an antioxidant layer forming liquid containing a polyvinyl alcohol solution as a main component as the other coating liquid. 18. A coating method for forming a plurality of layers on a continuously running strip-shaped base material, which comprises applying one coating solution to form a lower layer, and forming a lower layer on the lower layer.
When applying another coating liquid having the same or different composition as the one coating liquid to form the upper layer, if an uncoated portion in which the one coating liquid is not applied occurs when the lower layer is formed, A coating method comprising applying an undercoat liquid to the uncoated portion before the coating liquid is applied.