Coating device and coating film forming method

Abstract

The purpose of the present invention is to provide a coating apparatus and a coating-film forming method in which, when a coating material having a high viscosity is applied to the circumferential surface of a cylindrical base material and air is blown to flatten the coating film, the processing time is reduced to improve the productivity, and the occurrence of coating unevenness and coating streaks is reduced to improve the quality of the formed coating film. In order to achieve this purpose, the present invention provides a coating apparatus comprising at least one of: a coating means for applying a coating material on the circumferential surface of a cylindrical base material; a rotary driving means for rotating the cylindrical base material about the axis of the cylinder; an airflow jetting means for jetting an airflow to a part of the circumferential surface of the cylindrical base material; and a moving means for making the airflow jetting means movable so that the airflow is jetted to the circumferential surface to which the coating material is applied, wherein a plurality of the airflow jetting means are provided, and the airflow is jetted to the overall area of the circumferential surface, to which the coating material is applied, by the plurality of airflow jetting means, the moving means, and the driving means.

Description

[Technical Field]

[0001] The present invention relates to a coating device for coating a coating material on the peripheral surface of a cylindrical substrate and a coating film forming method. [Background technology]

[0002] In the fields of manufacturing printing plates used in flexographic printing and gravure printing, and photoreceptors and belts used in electrophotographic image forming devices, a coating film is formed on the peripheral surface of a cylindrical substrate, and various methods have been proposed for forming this coating film.

[0003] Methods for applying a coating material to the peripheral surface of a cylindrical substrate include, for example, dip coating, in which the substrate is immersed in a liquid tank and then pulled out, spiral coating, in which a coating is applied in a spiral pattern to the peripheral surface of the substrate, and spray coating, in which droplets are sprayed onto the peripheral surface of the substrate.

[0004] Among these, spiral coating, as shown in Patent Document 1, is a method in which a cylindrical substrate is rotated around its axis, and a coating material is discharged from the coating nozzle while the coating nozzle is moved relatively in the axial direction, and the coating material is applied in a spiral pattern to the circumferential surface of the cylindrical substrate to form a coating film.Spiral coating has the advantages of high utilization efficiency of the coating liquid, the ability to apply even high-viscosity coating materials, and the ability to dry and harden while rotating.

[0005] On the other hand, spiral coating tends to produce spiral coating streaks. To solve this problem, for example, Patent Document 2 discloses a method of flattening the coating film by blowing air onto the peripheral surface of a cylindrical substrate immediately after the coating material adheres to it. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 02-273576 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-055778 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional techniques have the following problems. In methods for flattening a coating film by spraying an airflow toward a coating material, the flattening process time can be long. For example, when flattening the entire surface of a coating film on the peripheral surface of a cylindrical substrate using a single airflow spraying means, the longer the distance that the airflow spraying means must travel, the longer the time required for the single airflow spraying means to scan the entire surface of the cylindrical substrate (flattening process time) becomes. In particular, under conditions that require a lot of energy for flattening, such as forming a high-viscosity coating film or a thin film, the movement speed of the airflow spraying means also becomes slow, further extending the flattening process time.

[0008] In contrast, Patent Document 2 proposes a slit-type air nozzle and a block-type air nozzle incorporating multiple air nozzles, both of which are capable of simultaneously blowing air in the entire axial direction. However, in both cases, the nozzle position is fixed in the axial direction during the flattening process, and unlike flattening processes performed by moving a single air nozzle, the nozzle does not move in the axial direction, so the force moving the coating material in the axial direction during the flattening process is weak. Therefore, sufficient flattening could not be achieved under conditions of high-viscosity coating materials or thin-film application.

[0009] In view of the above problems, the present invention aims to provide a coating device and coating method that can shorten processing time and improve productivity when a highly viscous coating material is applied to the peripheral surface of a cylindrical substrate and the coating film is flattened by blowing air, and that can form a high-quality coating film by performing sufficient flattening processing even when a highly viscous coating material or a thin coating is applied. [Means for solving the problem]

[0010] In order to solve the above problems, the coating device of the present invention has the following configuration: (1) A coating means for coating a coating material on the peripheral surface of a cylindrical substrate, a rotation drive means for rotating the cylindrical substrate around the axis of the cylinder as a central axis, an airflow injection means for injecting an airflow onto a part of the peripheral surface of the cylindrical substrate, and a device for controlling the airflow injection means so that the airflow is injected onto the peripheral surface to be coated with the coating material. In the axial direction of the cylindrical substrate The apparatus has at least one moving means for moving the coating material, and a plurality of the airflow spraying means are provided, and the airflow is sprayed over the entire area of ​​the peripheral surface to be coated by the plurality of airflow spraying means, the moving means, and the driving means, and the airflow is sprayed in a direction different from the direction in which the peripheral surface of the substrate rotates by the rotation driving means. The axial direction of the cylindrical substrate is The coating material is applied by moving the moving means, and the coating material is applied by moving the moving means of the application means. The cylindrical substrate in the axial direction and a moving means for moving the air jetting means. The cylindrical substrate in the axial direction The movement is an independently controllable application device.

[0012] (3) before duplication The coating device according to (1) or (2), wherein the several airflow jetting means are arranged at regular intervals in a direction parallel to the rotation axis of the cylindrical substrate, and each airflow jetting means maintains a constant gap in the radial direction from the circumferential surface of the cylindrical substrate.

[0013] (4) The coating device according to any one of (1) to (3), wherein the airflow spraying means further comprises a means for controlling the pressure of the sprayed airflow or the distance between the airflow spraying portion and the peripheral surface to which the coating material is applied.

[0014] (5) The airflow jetting means is movable. The cylindrical substrate in the axial direction In the coating device according to any one of (1) to (4), the moving means further comprises a means for controlling the moving distance and / or moving speed of the air current spraying means.

[0015] (6) The means for controlling the pressure of the jetted airflow is the airflow jetting means. The cylindrical substrate in the axial direction move meansThe coating device according to any one of (1) to (5) is provided with a determiner that determines the start point and / or end point of the movement in cooperation with the determining unit, and a controller that stores a program that receives information on the movement amount of the moving part and the pressure of the airflow and executes a predetermined scan.

[0016] (7) In the coating film forming method, a cylindrical substrate is rotated around the axis of the cylinder as a central axis, and a coating material is discharged onto the peripheral surface of the cylindrical substrate from a coating material discharge hole that moves linearly in the axial direction to form a coating film. condition group a step of using a plurality of airflow injection means to inject airflow toward a portion of the circumferential surface of the cylindrical substrate while rotating the cylindrical substrate at a rotational speed different from the rotational speed during coating, and injecting the airflow while moving the plurality of airflow injection means in a linear motion in the axial direction of the cylindrical substrate, wherein the step of injecting the airflow comprises arranging the plurality of airflow injection means at regular intervals in the axial direction, and moving the plurality of airflow injection means in a linear motion in the axial direction at the same speed while simultaneously injecting airflows, thereby injecting the airflow over the entire circumferential surface to be coated with the coating material.

[0017] (8) The method for forming a coating film according to (7), wherein the plurality of airflow injection means are air nozzles that inject airflow from injection holes, and the plurality of airflow injection means move axially at a constant speed while injecting airflow at a constant supply pressure or a constant flow rate, and before stopping movement, the air supply pressure or flow rate is continuously reduced from the constant supply pressure or constant flow rate.

[0018] (9) The method for forming a coating film according to (7), wherein the plurality of airflow injection means are air nozzles that inject airflow from injection holes, and the plurality of airflow injection means move in the axial direction at a constant speed while injecting airflow at a constant supply pressure, and the speed of movement is continuously increased from the constant speed before stopping.

[0019] (10) A method for producing a waterless lithographic printing plate precursor, characterized in that a coating film made of a silicone material is formed on the peripheral surface of a cylindrical substrate using the coating film formation method according to any one of (7) to (9). [Effects of the Invention]

[0020] By using the coating device and coating film forming method of the present invention, it is possible to flatten the film surface in a short time even under coating conditions such as coating a high-viscosity coating liquid or coating a thin film on the peripheral surface of a cylindrical substrate, and to form a coating film around the entire circumference of the cylindrical substrate with high productivity. Furthermore, it is possible to flatten coating unevenness in the axial direction, making it difficult for coating unevenness to remain after the flattening process, and it is possible to form a coating film of good quality across the entire width. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic perspective view showing an embodiment of a coating device according to the present invention; [Figure 2] 1 is a schematic front view showing an embodiment of a coating device according to the present invention. [Figure 3] 1 is a schematic plan view showing an embodiment of a coating apparatus according to the present invention; [Figure 4] 1 is a schematic side view showing an embodiment of a coating apparatus according to the present invention. [Figure 5] FIG. 2 is a schematic diagram of a cross section of a coating film showing the form of coating streaks. [Figure 6] 1 is a schematic diagram illustrating an embodiment of a coating film planarization method. [Figure 7] 10A and 10B are diagrams showing the relationship between the supply pressure and the travel distance of the air jetting means in the flattening operation, and the relationship between the travel speed and the travel distance of the air jetting means in one embodiment. [Figure 8] 10A and 10B are schematic diagrams showing measurement results showing changes in film thickness profile during planarization operation. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present invention will be understood based on the following description and drawings, but the embodiments of the present invention are not limited to these.

[0023] <Configuration of coating equipment> FIG. 1 is a schematic diagram showing an example of a coating device. FIG. 1(a) shows the configuration when coating is mainly performed, and FIG. 1(b) shows the configuration when spraying airflow to flatten the coating film. FIGS. 2, 3, and 4 are a front view, a plan view, and a right side view, respectively, showing in detail the coating device 100 during the coating operation shown in FIG. 1(a). As shown in FIG. 1(a), the coating device 100 shown in FIG. 1 rotates a cylindrical substrate 111 to be coated about its axis while moving a discharge nozzle 121 that dispenses the coating material in the axial direction of the cylindrical substrate 111. Coating material F is then applied to the outer peripheral surface of the substrate. Then, as shown in FIG. 1(b), the cylindrical substrate 111 is rotated about its axis while spraying airflow toward the coating material F on the outer peripheral surface of the substrate. By moving multiple airflow spraying means, arranged at regular intervals, in the axial direction of the cylindrical substrate 111, the coating material is flattened.

[0024] In FIG. 1, one airflow injection means is represented by one airflow injection unit 141. For example, a hole is provided at the tip of the airflow injection unit 141 to inject an airflow, allowing the airflow to be injected onto a portion of the circumferential surface of a cylindrical substrate. The airflow injection hole may be circular or slit-shaped. Note that in FIG. 1, only the end airflow injection unit 141 is designated by a reference numeral as one airflow injection means, but the nozzle-like portions protruding from the airflow injection head 142 represent multiple airflow injection units 141, i.e., multiple airflow injection means are provided. In FIG. 1(b), the multiple airflow injection units 141 can be moved axially using a moving means for the airflow injection means. The moving means for the airflow injection means is connected to a moving mechanism consisting of a stage 151, a slider 152, and an actuator 153.

[0025] When forming a coating film, the airflow needs to be sprayed over a small area per airflow spraying means, and multiple airflow spraying means spray the airflow evenly across the entire surface to be coated. The estimated time (minutes) for the flattening process can be calculated by dividing the travel distance (S) (m) of one airflow spraying means by the travel speed (m / min) of the cylindrical substrate length (L). This is an example of a coating device with multiple movable airflow spraying means that sprays airflow across the entire surface of the cylindrical substrate to which the coating material has been applied. After spirally applying the coating material to the surface of a rotating cylindrical substrate to form a coating film, the device simultaneously moves multiple airflow spraying means in a direction parallel to the pivoting axis of the cylindrical substrate, colliding air or other particles with the coating material applied to the surface to flatten the coating. Flattening is also known as leveling.

[0026] The coating device 100 of the present invention includes a rotation drive means 110 that rotates a cylindrical substrate 111 shown in Fig. 3, a coating means that ejects a coating material shown in Fig. 4, a coating means moving means that moves the coating means shown in Fig. 2 and Fig. 3 in the longitudinal direction of the substrate (Y direction in the figures), an airflow injection means that injects an airflow onto part of the circumferential surface of the cylindrical substrate 111 shown in Fig. 3 and Fig. 4, and a means for moving the airflow injection means that can move the airflow injection means shown in Fig. 3 and Fig. 4. The cylindrical substrate 111 is a substrate having a cylindrical outer shape, and includes hollow cylindrical substrates.

[0027] The rotation drive means, the coating means, the means for moving the coating means, the air jetting means, and the means for moving the air jetting means will be described in detail below.

[0028] <Rotational drive means> The rotation drive means 110 shown in Figures 2 and 3 includes left and right rotation center shafts 112 and 113 that support the rotation of a cylindrical substrate 111, support bases 114 and 115 that support the rotation center shafts, an actuator 116 connected to the rotation support shafts to rotate the cylindrical substrate 111, and a rotation speed controller 117 that controls the actuator and thereby the rotation speed of the cylindrical substrate 111. The rotation drive means can rotate the cylindrical substrate 111 at any rotation speed, and the rotation speed of the cylindrical substrate 111 can be set to a rotation speed suitable for coating or for flattening the coating film using the airflow spray means. The rotation drive means is preferably controlled independently of the means for moving the coating material discharge holes and the means for moving multiple airflow spray means, i.e., the arrow (symbol P) in Figure 1.

[0029] <Coating means and its transportation means> The coating means shown in Figure 4 includes a discharge nozzle 121 that discharges the coating material from a discharge hole, a coating head 122 that supplies the coating material, a metering pump 123, and a coating material tank 124 that stores the coating material. The coating liquid passes through a flow path (not shown) in the coating material tank 124 within the coating head 122, and can be continuously discharged at any discharge rate from the discharge hole of the discharge nozzle 121. There are no limitations on the method of discharging the coating material from the discharge nozzle 121, and it may be in the form of droplets or a curtain, but a liquid column is preferable.

[0030] 2 and 3 includes a stage 131 that supports the coating head 122, a slider 132 along which the stage moves, an actuator 133 that drives the slider, and a controller 134 that controls the actuator, and is capable of moving the coating head 122 at any speed in the axial direction of the cylindrical substrate 111. The longitudinal direction is a direction parallel to the central axis of the cylindrical substrate. The stage 131 has an adjustment mechanism that adjusts the distance between the discharge nozzle 121 in the coating head 122 and the cylindrical substrate 111. If the coating head 122 is equipped with multiple discharge nozzles 121, the adjustment mechanism may be provided for each discharge nozzle.

[0031] The coating means preferably includes a moving means for moving the coating material discharge holes in a direction different from the direction in which the peripheral surface of the substrate rotates by the rotation drive means. The coating material is preferably applied to the peripheral surface of the cylindrical substrate by moving the moving means, and the coating material is applied in a spiral pattern, resulting in coating material F being disposed on the peripheral surface. In this case, coating material F takes the form of a coating film having uncoated areas as shown in Figure 5(a) or a coating film having irregularities as shown in Figure 5(b).

[0032] <Airflow injection means and its movement means> Fig. 4 is a schematic diagram of a cylindrical base material viewed from the side. The airflow injection means shown in Fig. 4 is represented by airflow injection section 141. One airflow injection means has at least one airflow injection section 141, and multiple airflow injection means are arranged side by side in the axial direction of the cylindrical base material.

[0033] It is preferable that the plurality of airflow injection sections, i.e., airflow injection means, are arranged at regular intervals in a direction parallel to the pivot axis of the cylindrical base material, and that each airflow injection means maintains a constant gap in the radial direction from the circumferential surface of the cylindrical base material.

[0034] That is, as shown in FIG. 3, the multiple airflow injection means are provided with airflow injection sections 141 that inject multiple airflows at regular intervals in the longitudinal direction of the cylindrical substrate 111, airflow injection heads 142 that supply gas to the airflow injection sections 141, pressure control units 143 that control the pressure of the gas supplied to the airflow injection heads, and compressed gas supply sources 144 that supply compressed gas to the pressure control units, and are capable of continuously injecting gas G toward the outer peripheral surface of the cylindrical substrate 111.

[0035] In Figure 3, airflow injection means is represented by airflow injection unit 141, and there are multiple airflow injection units 141, which are provided on airflow injection head 142. The airflow injection units 141 are fixed to airflow injection head 142 with bolts at positions that are evenly spaced apart in the axial direction, and this attachment position can be adjusted by changing the fixing point. Airflow injection unit 141 has an injection hole that injects the airflow, and the injection hole is oriented toward the surface of the cylindrical substrate, so that the airflow is sprayed onto the coating material F on the peripheral surface.

[0036] In addition, in FIG. 3, the airflow injection unit 141 is an independent nozzle with individual gas supply ports, and is configured as an integrated unit by being fixed to the airflow injection head 142. However, the airflow injection head 142 may be a distribution pipe with a manifold, and the airflow injection head 142 may be provided with multiple airflow injection holes connected to the manifold, and these airflow injection holes may replace the airflow injection unit 141. The airflow injection means injects an airflow from the airflow injection unit 141 toward a portion of the peripheral surface to which the coating material has been applied. Multiple airflow injection units 141 are provided, and the airflow is injected over the entire peripheral surface to which the coating material has been applied by the multiple airflow injection means, their movement means, and their drive means. There are no limitations on the structure of the airflow injection unit 141, and the cross-sectional shape may be circular, slit-shaped, or the like. Furthermore, the pressure value controlled by the pressure control unit 143 may be linked to the movement means of the airflow injection means shown in FIG. 3 and controlled to a pressure value corresponding to the movement position. Although the air jetting means and its moving means are not shown in FIG. 2, the air jetting means and its moving means are located deep inside the cylindrical base material 111.

[0037] In the present invention, "the air current jetting means is provided in a plurality" means that the air current jetting means and the moving means are integrated or may operate independently, and the moving means may be a single moving means in which a plurality of air current jetting means are integrated. Furthermore, as mentioned above, the air current jetting means is represented by an air current jetting section having an injection hole for injecting the air current, and if there are a plurality of locations from which the air current is injected, it is considered to be a plurality of air current jetting means.

[0038] 3 shows an example of a movement mechanism for the airflow injection unit 141. The movement means for the airflow injection means includes a stage 151 that supports the airflow injection head 142, a slider 152 along which the stage moves, an actuator 153 that drives the slider, and a control device 154 that controls the actuator, and can move the airflow injection head 142 in the longitudinal direction of the cylindrical substrate 111 at any speed. The movement speed at this time may be controlled so as to change depending on the movement position. In addition, the stage 151 has a mechanism that adjusts the distance between the airflow injection head 142 and the cylindrical substrate 111, thereby adjusting the distance between the airflow injection unit 141 and the cylindrical substrate 111.

[0039] Here, it is preferable that the multiple airflow injection holes of the multiple airflow injection units 141 maintain a constant radial distance from the circumferential surface of the cylindrical substrate 111. This is to stably control the airflow from the multiple airflow injection holes. Maintaining a constant radial distance from the circumferential surface of the cylindrical substrate means that, when the cylindrical substrate rotates, the radial distance between the surface of the circumferential surface of the cylindrical substrate and the injection holes of the multiple airflow injection means is maintained at the same distance over the entire circumference. If the multiple airflow injection means maintain the same distance, for example, before stopping axial movement, the arrangement of the multiple airflow injection means may move radially while maintaining a state parallel to the rotation axis of the substrate.

[0040] Furthermore, the means for moving the air current ejection head 142 and the air current ejection means may be one or more. When multiple means for moving the air current ejection means are provided, it is preferable that the respective means for moving the air current ejection means operate in conjunction with each other. From this perspective, it is preferable that the number of means for moving the air current ejection means is one.

[0041] Furthermore, the moving direction of the airflow injection head 142 may be a direction different from the axial direction of the cylindrical base material 111, as long as the airflow is injected over the entire peripheral surface of the cylindrical base material. Also, in the drawing, the airflow injection units 141 are shown in a single row, but multiple rows may be used.

[0042] The gas G may be an inert gas such as dry air or nitrogen.

[0043] In the coating device of the present invention, the means for controlling the pressure of the sprayed airflow preferably includes a determiner that is linked to the movement means of the airflow spraying means and determines the start and / or end points of movement, and a controller that inputs information about the movement amount of the movement means and the airflow pressure and stores a program for executing a predetermined scan. The area in which one airflow spraying means performs the flattening process on the coating film preferably determines the start and end points of movement of another airflow spraying means adjacent in the direction of movement, and inputs information about the movement amount of the movement means and the airflow pressure to perform the predetermined scan so that the flattening process on the coating film is performed on the entire area. As described above, the coating device has an airflow spraying means for spraying an airflow onto a portion of the circumferential surface of a cylindrical substrate, and multiple airflow spraying means, their movement means, and rotation drive means stably spray the airflow over the entire surface to which the coating material is applied, thereby enabling the flattening process on the film surface in a short time and forming a coating film around the entire circumference of the cylindrical substrate with high productivity.

[0044] Furthermore, from the viewpoint of stabilizing the formation of the coating film, the coating device of the present invention may be provided with a mechanism for adjusting the temperature of the substrate and the coating means or the airflow spraying means, etc. Also, the coating film thickness measuring device for monitoring the state of planarization of the coating film and the coating film thickness inspection device may be provided.

[0045] <Coating method and flattening treatment> By using the coating device 100 having the above configuration to apply the coating material and to perform the flattening process of the coating film, a flat coating film can be formed on the entire circumference of the cylindrical substrate 111 in a short time.

[0046] First, the coating method will be described. In the coating material filling process, coating material is filled into coating material tank 124 shown in FIG. 4, thereby filling metering pump 123, coating head 122, discharge nozzle 121, and the piping connecting the components. In the coating operation process, cylindrical substrate 111 is fixed to rotary support shafts 112 and 113, and then, in coating device 100 shown in FIGS. 1 to 4, cylindrical substrate 111 is rotated about its axis as a central axis while coating head 122, which discharges coating material, moves in the axial direction of cylindrical substrate 111, thereby coating coating material F on the circumferential surface of the substrate. The scope of application of the present invention is not particularly limited, but the coating material viscosity is preferably 100 cP to 100,000 cP, more preferably 500 cP to 5,000 cP, and the film thickness immediately after application is 20 μm or less.

[0047] The target coating thickness of coating material F is determined, and the amount of coating material F dispensed, the rotation speed of the cylindrical substrate 111, and the Y-direction movement speed of the coating head 122 are appropriately set. The set values ​​for various quantities are determined taking into consideration the circumferential scattering of the coating material, the accuracy of the coating material placement on the circumferential surface of the cylindrical substrate 111, and productivity. As a result, depending on the combination of the coating material properties and the set amounts, coating material F can take the form of a flat coating, a coating with uncoated areas as shown in Figure 5(a), or a coating with unevenness as shown in Figure 5(b). If the resulting coating has streaks, a flattening process is performed in which an airflow impinges on the coating material F. However, if the coating material viscosity is high and the target film thickness is thin, the energy required for flattening is large, and the movement speed of the airflow injection unit must be slowed, resulting in a long flattening process time. In this case, the flattening process time can be shortened by flattening using multiple airflow injection units as proposed in the present invention.

[0048] At this time, the surface to which the coating material has been applied is in a state where it can be flattened, with spiral coating streaks spreading out in all directions. As explained in Figure 1, after the coating film has been applied to the entire circumference and width, it is preferable to flatten the coating film by using multiple airflow spraying means, their movement means, and drive means, and moving the airflow spraying means in the axial direction of the cylindrical substrate 111.

[0049] After discharging the coating material F to form a coating film, the method includes a step of using a plurality of airflow injection means that inject airflows toward a portion of the circumferential surface of the cylindrical substrate while rotating the cylindrical substrate at a speed different from the rotation speed during coating, and injecting the airflows while moving the plurality of airflow injection means linearly in the axial direction of the cylindrical substrate. This step is a step of flattening the coating material F on the circumferential surface of the substrate.

[0050] In the step of spraying the airflow, a plurality of airflow spraying means are arranged at regular intervals in the axial direction, and the plurality of airflow spraying means move linearly in the axial direction at the same speed while simultaneously spraying airflows, spraying the airflow over the entire area of ​​the peripheral surface to be coated with the coating material, and forming a coating film while flattening the coating material F. In the coating method of the present invention, airflows are sprayed over the entire area of ​​the peripheral surface to be coated with the coating material by a plurality of airflow spraying means, so after the coating material has been applied, the area covered by the spray area of ​​each airflow is narrow relative to the entire peripheral area of ​​the surface, shortening the flattening process time and improving productivity.

[0051] Using Figure 6, the process of spraying an airflow to flatten the coating film will be explained. As shown in Figure 6(a), after coating is completed, the moving means of the airflow spraying means is driven, and the airflow spraying head 142 is moved to a predetermined starting position. At this time, the airflow spraying unit 141 located at the leftmost end in the Y direction is positioned above the leftmost end of the peripheral surface topcoat material F of the cylindrical substrate 111. Then, the cylindrical substrate 111 is rotated at a rotation speed suitable for the flattening process, and the airflow spraying unit 141 begins to move at a predetermined speed in the axial direction of the cylindrical substrate 111. The cylindrical substrate 111 is rotated at a speed different from the rotation speed during coating. From the perspective of moving the coating film by the airflow, it is preferable to reduce the rotation speed.

[0052] At the same time, the pressure control unit 143 controls the gas supply pressure, increasing the supply pressure from 0 to a predetermined supply pressure and injecting gas G. The injected gas G then collides with the coating film, causing a liquid flow in the coating film at the impact surface. The airflow injection unit 141, which serves as the airflow injection means, moves while the liquid surface of the coating film is pressed against the circumferential surface by the pressure of the gas G. This adds a liquid flow from the source to the destination, promoting the flattening of the coating film. When multiple airflow injection units 141 are incorporated into the airflow injection head 142, they are easily spaced apart in the axial direction, and the multiple airflow injection units can easily move linearly in the axial direction at the same speed while injecting airflows. In this case, the gas injection head 142 equipped with multiple airflow injection units 141 is preferably oriented perpendicular to the coating film to maximize the pressing pressure generated by the gas G. Furthermore, since the slower the movement speed of the gas injection head 142, the more likely liquid flow is to occur, by simultaneously injecting gas G from multiple air flow injection sections 141 while moving the gas injection head 142, it is possible to perform flattening processing of the coating film over a wide area in a short time even at a slow movement speed.

[0053] That is, in the case of the streaky coating liquid film thickness shown as an example in Fig. 8(a), the coating streaks can be efficiently and uniformly flattened by using multiple airflow injection means of the present invention, which are moved simultaneously while injecting airflows at a constant axial interval. In other words, if the airflow injection holes arranged at a constant axial interval are not moved simultaneously in the axial direction, a streaky film thickness shape will remain, as shown in Fig. 8(d), and flattening effects will not be achieved.

[0054] 6(b), when the airflow ejection unit 141 moves to a predetermined stopping position and completes airflow ejection onto the entire coating surface, the driving of the moving means of the airflow ejection means and the rotational driving of the cylindrical substrate 111 are stopped, and the pressure control unit 143 controls the gas supply pressure to reduce the supply pressure to 0, thereby stopping the ejection of gas G. The stopping position of the airflow ejection unit 141 is preferably input in advance to the controller 154 that controls the movement of the airflow ejection means, and the movement is stopped. The stopping position is set so as to be at least beyond the position where another airflow ejection unit 141 adjacent in the movement direction starts moving.

[0055] In this planarization process, the distance traveled by the airflow injection unit 141 in the axial direction of the cylindrical substrate 111 is the sum of the pitch between the airflow injection units in the substrate axial direction and the length over which adjacent airflow injection units pass over the planarized coating film. As can be seen from this relationship, in order to shorten the planarization process time, it is effective to increase the number of airflow injection units, shorten the pitch between the airflow injection units in the substrate axial direction, and shorten the length over which adjacent airflow injection units pass over the planarized coating film.

[0056] Here, when forming a more precisely flat surface, another airflow injection unit passes over the coating film that has been flattened by the passage of an airflow injection unit, and stops on the flat coating film. However, if the supply pressure is constant, a thick film portion in the form of a liquid puddle (coating streak at the stop position) as shown in Figure 5(c) may occur at the stop position.

[0057] This phenomenon can occur even when air is sprayed uniformly across the entire width using a slit-type air nozzle. If the slit width is shorter than the width of the coating film, the coating film pushed by the air spreads toward the coating edge, which can result in streaky coating unevenness from both ends of the slit width to the outside. If both ends of the coating film formed are trimmed in post-processing, coating unevenness at the edges is less of a problem. However, if high-precision thickness uniformity across the entire width is required, the following conditions are preferred to prevent coating unevenness.

[0058] In this case, the thick-film puddles are caused by the fluid flow caused by the collision of gas G, and the amount of thick-film puddles increases with increasing gas G injection pressure. In other words, the higher the injection pressure at the end of the planarization process, the more likely thick-film regions remain. Therefore, to improve these thick-film regions, i.e., coating unevenness, it is preferable to gradually reduce the supply pressure and then stop the processing operation after planarizing the entire coating film at the supply pressure required for planarization, rather than immediately stopping the processing operation. This results in a smoother film surface without leaving thick-film regions, as shown in Figure 5(c). That is, it is preferable for the multiple airflow injection devices to move axially while injecting airflow at a constant supply pressure, and to reduce the amount of movement of the coating film by continuously reducing the air supply pressure from the constant supply pressure during the section from the end of planarization of the entire coating film to the end of movement. This allows the coating liquid in the thick-film regions created by the injection pressure to be dispersed and consumed on the coating film, thereby preventing the formation of thick-film regions when the processing operation is stopped.

[0059] As an example, Figure 7(a) shows the relationship between supply pressure and the travel distance of the air jetting part. As shown in this graph, gas G is sprayed at a constant supply pressure until the travel distance reaches X1, and after the travel distance reaches X1, the supply pressure is continuously reduced to reduce the impact force of the air jet, reducing the amount of paint travel and forming a flat coating film.

[0060] Another similar method is to increase the moving speed of the air jetting part. By increasing the moving speed, the magnitude of the liquid flow caused by the collision of gas G decreases even when the jetting pressure is constant, and therefore the same effect can be obtained as when the jetting pressure is decreased.

[0061] An example of this is shown in Figure 7(b). This is a graph showing the relationship between the movement speed and movement distance of the airflow injection unit 141, i.e., the airflow injection means. In the control operation, gas G is injected at a constant movement speed until the movement distance reaches X1. After the movement distance reaches X1, the movement speed is continuously increased to reduce the collision force of the airflow and reduce the amount of coating material moved while forming a coating film. It is preferable to set the supply pressure to approximately zero when movement stops. The movement distance X1 at which the supply pressure starts to decrease and the rate of decrease in supply pressure in Figure 7(a) are set to values ​​that can flatten the coating streaks shown in Figure 5(a) or (b) and flatten the puddle-like coating streaks shown in Figure 5(c). Furthermore, the magnitude of the constant movement speed in the graph shown in Figure 7(b) is set to a magnitude that flattens the coating streaks shown in Figure 5(a) or (b) based on a constant cylindrical substrate rotation speed and a constant supply pressure. In addition, the movement distance X1 at which the movement speed starts to increase in FIG. 7(b) and the rate of increase in the movement speed are set to values ​​that can flatten the coating streaks shown in FIG. 5(a) or (b) and flatten the puddle-like coating streaks shown in FIG. 5(c).

[0062] In the process of spraying an airflow to flatten the coating film, in order to move the airflow spraying unit 141, which is the airflow spraying means, stably at a low speed, the airflow spraying head 142 is mounted on a stage 151 and a slider 152, and movement is enabled by driving an actuator 153 provided at the end of the stage. Furthermore, it is preferable that a controller 154 that controls the movement controls the drive of the actuator 153 based on information on the amount of movement and stoppage. Furthermore, in order to continuously reduce the supply pressure after the movement distance reaches X1, it is also preferable that the controller 154 that controls the movement sends a signal to the airflow spray pressure controller 143 to reduce the spray pressure and mitigate the movement of the coating film.

[0063] <About the curing of the coating> After the coating film is flattened, the coating film is cured to stop the flow of the coating liquid. The curing method is not limited to heat curing, UV curing, etc., but it is preferable to perform the curing while maintaining a rotating state in order to suppress the liquid flow after flattening.

[0064] <About the shape of the substrate> The cylindrical substrate to which the present invention is applicable may be any substrate having a cylindrical outer shape, and includes a substrate having a hollow cylindrical shape.

[0065] <Application to the production of waterless lithographic printing plate precursors> One effective application of the present invention is in the manufacturing process of waterless lithographic printing plate precursors for waterless printing, which includes the process of applying a thin film of a highly viscous coating material to a cylindrical substrate. Waterless printing is known as an environmentally friendly printing method because it does not use dampening water containing organic solvents. However, in recent years, there has been a demand for methods to form functional films that minimize the use of organic solvents not only in the printing process but also in the plate manufacturing process. When the dilution of coating materials with organic solvents is restricted, it becomes necessary to deal with high-viscosity coating materials and apply them in thin films. One such application is the coating process of the surface silicone film, which is the functional film that constitutes a waterless lithographic printing plate precursor, and by applying the present invention, a uniform thin film can be formed.

[0066] In the manufacturing process of a waterless lithographic printing plate precursor, a precursor substrate before the formation of a silicone layer is used as the cylindrical substrate in the present invention, and a silicone material coating material is applied to the coating material by the above-mentioned coating method, and then spread thinly by a flattening means to form a uniform coating film. The coating film formation conditions in this case are described in Example 4. [Example]

[0067] Examples of specific embodiments of the present invention will be described below using examples, but the present invention is not limited to these examples in any way.

[0068] Example 1 A coating film was formed on a cylindrical substrate using a coating device with the same configuration as shown in Figures 1 to 4. A cylindrical substrate with an outer diameter of 185 mm was set in the coating device and rotated at 400 rpm. Next, the coating material was placed on the peripheral surface so that the film thickness would be 5.0 μm when a uniformly flat coating film was formed on the peripheral surface of the cylindrical substrate. The shear viscosity was 1 × 10 3A coating material of 31 μL / sec was used. The coating material was discharged in a column shape from a nozzle with an outlet diameter of 0.25 mm at a rate of 31 μL / sec. The coating material was then moved in a parallel direction along the axis of the cylindrical substrate at a rate of 10.7 mm / sec, forming a spiral around the cylindrical substrate.

[0069] To improve the accuracy of the placement of the coating, the nozzle was oriented in the direction of rotation of the cylindrical substrate, and the clearance between the nozzle tip and the cylindrical substrate in the radial direction of the cylindrical substrate was set to 2 mm. As a result, the coating materials on the circumferential surface of the cylindrical substrate did not bond together, resulting in uncoated areas 201 between adjacent coating materials, as shown in Figure 5(a). The coating and flattening processes were performed at room temperature of 23°C.

[0070] In this example, the airflow injection means corresponds to an airflow injection unit 141, and a plurality of airflow injection units 141 were arranged in a line in the axial direction of the cylindrical base material. As shown in Fig. 3, a plurality of airflow injection units 141 were mounted on an airflow injection head 142, which were connected to a moving mechanism consisting of a stage 151, a slider 152, and an actuator 153. The airflow injection unit 141 had a nozzle-shaped injection hole at its tip for injecting an airflow.

[0071] Following placement of the coating material, a flattening process was performed using multiple airflow injection units 141. The rotation speed of the cylindrical substrate was reduced to 25 rpm. The gap between the cylindrical substrate and the substrate was set to 5 mm. Air-pressurized airflow was injected from each injection hole so that the pressure when colliding with the peripheral surface was 140 kPa, and the multiple airflow injection units 141 were translated in the axial direction at a speed of 0.20 mm / s.

[0072] Specifically, the pitch between the airflow injection means, i.e., the airflow injection units, was 20 mm, the number of injection units was 16, and the airflow rate injected from each airflow injection unit was adjusted to be equal, and they were arranged along the axial direction of the cylindrical substrate. The airflow injection units were tapered nozzle-shaped with an outlet diameter of 1.6 mm. The length over which an adjacent airflow injection unit passed over the flattened coating film was 20 mm, and the travel distance of the airflow injection means, i.e., the airflow injection units, was 40 mm. The supply pressure was set to 0.19 MPa in the 0 mm to 40 mm range, and the airflow was injected.

[0073] Through the above process, the uncoated area 201 between the coating material and the adjacent coating material could be made to appear flat. Furthermore, when there was one airflow injection unit, the flattening process time was approximately 5,000 seconds (about 1.4 hours) per meter of cylindrical substrate length. On the other hand, when multiple airflow injection units were provided with a 20 mm pitch between the airflow injection units, the flattening process time was reduced to 200 seconds (about 3 minutes) per meter of cylindrical substrate length. In other words, by providing multiple airflow injection units, the flattening process time could be reduced to 1 / 25 of that when there was only one airflow injection unit.

[0074] <Example 2> A coating film was formed on a cylindrical substrate using a coating device having the same configuration as that shown in Figures 1 to 4. The pressure of the pressurized air from the nozzle-shaped air jetting unit, which is the air jetting means, was adjusted. The adjustment was the same as in Example 1, based on the graph shown in Figure 7(a), except that the supply pressure was kept constant in the range of 0 to 10 mm from the distance from the movement start position, and the supply pressure was linearly reduced to 0.11 MPa in the range of 10 to 40 mm. By providing multiple airflow injection units, the planarization process time was shortened compared to when a single airflow injection unit was used. Furthermore, by controlling the supply pressure, the occurrence of thick film puddles, as shown in Figure 5(c), was suppressed at each of the positions where the multiple airflow injection units stopped. Regarding the film thickness profile at the airflow injection unit stop position, Figure 8(b) shows the film thickness profile for Example 1, and Figure 8(c) shows the film thickness profile for Example 2. That is, (b) shows the film thickness profile without supply pressure control, and (c) shows the film thickness profile with supply pressure control. By controlling the supply pressure in Example 2, the maximum film thickness near the airflow injection unit stop position was reduced from 6.0 μm to 5.2 μm, resulting in the formation of a more uniform, high-quality coating surface. Here, similar effects were obtained by controlling the movement speed of the airflow injection unit based on the graph shown in Figure 7(b).

[0075] Example 3 A coating film was formed on a cylindrical substrate using an application device having the same configuration as that shown in Figures 1 to 4. The process of applying the coating material in a spiral shape on the circumferential surface of the cylindrical substrate was the same as in Example 1.

[0076] Next, the rotation speed of the cylindrical substrate was reduced. Then, a gap was set between the cylindrical substrate and the air-pressurized airflow injection means, and the airflow injection means was moved in parallel at a constant speed. The airflow injection means had a constant pitch between the airflow injection units, and the air flow rate injected from each airflow injection unit was adjusted to be the same as in Example 1. Multiple airflow injection units were arranged along the circumferential direction of the cylindrical substrate, and the airflow injection means was multiplexed in the circumferential direction. Then, the supply pressure was kept constant, and the airflow was injected.

[0077] Through the above process, the uncoated area 201 between the coating material and the adjacent coating material could be made flat in appearance. In addition, since the airflow injection means was multiplexed in the circumferential direction, the time during which the airflow was injected in the rotational direction was extended, and the axial movement speed was increased compared to the movement speed of the airflow injection means in Example 1. By providing multiple airflow injection units, the flattening process time could be shortened compared to when there was only one airflow injection unit.

[0078] Example 4 A waterless lithographic printing plate precursor was manufactured using a manufacturing apparatus equivalent to the configuration shown in Figures 1 to 4. A silicone coating material was applied to a cylindrical substrate to form a layer. The cylindrical substrate before the silicone coating material was applied had an outer diameter of 185 mm and an axial length of 1000 mm. The silicone coating material was used. As in Example 1, the silicone coating material was applied using a nozzle with an outlet diameter of 0.25 mm. A liquid column was discharged at a discharge rate of 31 μl / sec while the cylindrical substrate was moved parallel to the axial direction at 10.7 mm / sec., resulting in an average film thickness of 5.0 μm on the peripheral surface of the cylindrical substrate. Subsequently, using an airflow injection unit 141 with the same configuration as in Example 1 and under the same conditions as in Example 2, a flattening process was performed on the silicone coating film across the entire axial width. The silicone coating film was flattened over a period of 200 seconds, forming a uniform 5.0 μm silicone layer. Similar effects were obtained even when a separate coated layer was previously formed on the cylindrical substrate. The silicone coating material was prepared as follows.

[0079] <Silicone coating material> The following components (a-1), (b-1), and (c-1) were placed in a sealable container, and after sealing the container, the components were stirred and mixed at room temperature until uniform. Component (d-1) was placed in the resulting composition, and after sealing the container, the components were stirred and mixed at room temperature until uniform, to obtain a coating material. (a-1) DMS-V31 (dimethylvinylsiloxy-terminated polydimethylsiloxane, weight-average molecular weight: 28,000, average number of vinyl groups per molecule: 2, manufactured by GELEST Inc.): 95.89 parts by mass (b-1) “DOWSIL” (registered trademark) SRX212 Catalyst (platinum mixture, manufactured by Dow Toray Industries, Inc.): 0.11 parts by mass (c-1) 3,5-dimethyl-1-hexyn-3-ol (Tokyo Chemical Industry Co., Ltd.): 0.30 parts by mass (d-1) “SILASTIC” (registered trademark) RD-1 Catalyst (both terminal trimethylsiloxy-methylhydrosiloxane / dimethylsiloxane copolymer, weight average molecular weight: 750, average number of SiH groups in molecule: 5, manufactured by Dow Toray Industries, Inc.): 4.00 parts by mass.

[0080] <Comparative Example 1> The process of spirally disposing the coating material on the peripheral surface of the cylindrical substrate is the same as in Example 1. Next, the rotation speed of the cylindrical substrate was reduced. A slit nozzle with approximately the same width as the substrate was used as the airflow injection means. The long direction of the wide slit nozzle was aligned with the axial direction of the cylindrical substrate, and the position was fixed. No movement in the axial direction was performed. Then, the supply pressure was kept constant, and the airflow was injected.

[0081] As a result, the amount of coating material moving in the axial direction was insufficient, and the coating film could not be flattened. Although there was a large amount of coating material moving in the circumferential direction of the cylinder, the amount of coating material moving in the axial direction was insufficient because the airflow injection part did not move in the axial direction of the cylinder. In addition, uneven coating occurred at the ends of the slit.

[0082] <Comparative Example 2> The process of spirally distributing the coating material on the circumferential surface of the cylindrical substrate was the same as in Example 1. Subsequently, the rotation speed of the cylindrical substrate was reduced. As the airflow injection means, multiple airflow injection sections 141, as shown in Example 1 and Figure 3, were arranged across the entire width of the cylindrical substrate at a narrower pitch of 5 mm than in Example 1. The supply pressure was kept constant and the airflow was injected without axial movement. That is, the airflow injection means, which is the airflow injection section, was injected from each injection hole while the movement of the airflow injection hole (airflow injection section) remained stationary. Figure 8(a) shows the film thickness profile before airflow injection, and Figure 8(d) shows the film thickness profile after airflow injection. As a result of film thickness flattening, the amount of coating material moving in the axial direction was insufficient, and as shown in Figure 8(d), film thickness unevenness during application was not flattened in the thickness range of 3.0 to 7.0 μm. [Explanation of symbols]

[0083] 100: Coating device 110: Rotation drive means 111: Cylindrical base material 112, 113: Rotation axis 114, 115: Support stand 116: Actuator 117: Rotation speed controller 121: Discharge nozzle 122: Application head 123: Metering pump 124: Paint tank 131: Stage 132: Slider 133: Actuator 134: Controller for controlling movement of application means 141: Airflow injection part 142: Air jet head 143: Air jet pressure controller 144: Compressed gas supply source 151: Stage 152: Slider 153: Actuator 154: Controller for controlling the movement of the airflow jetting means 200: Uneven coating 201: Uncoated area between coating material and adjacent coating material 202: Coating streak F:Painting material G: Gas R: Rotation direction P: Linear movement direction

Claims

1. The coating device has at least one coating means for coating the circumferential surface of a cylindrical substrate with a coating material, a rotation drive means for rotating the cylindrical substrate around the axis of the cylinder as a central axis, an airflow injection means for injecting an airflow onto a part of the circumferential surface of the cylindrical substrate, and a moving means for moving the airflow injection means in the axial direction of the cylindrical substrate so that the airflow is injected onto the circumferential surface to be coated with the coating material, A coating device comprising a plurality of the air flow injection means, and an air flow is injected over the entire circumferential surface to be coated by the plurality of air flow injection means, the moving means, and the rotation drive means; the coating means comprises a moving means for moving the coating material discharge hole in the axial direction of the cylindrical substrate, which is a direction different from the direction in which the circumferential surface of the substrate rotates by the rotation drive means; the coating material is applied by moving the moving means; and the movement of the discharge hole in the axial direction of the cylindrical substrate by the moving means of the coating means and the movement of the air flow injection means in the axial direction of the cylindrical substrate by the moving means that moves the air flow injection means can be controlled independently.

2. 2. The coating device according to claim 1, wherein the plurality of air flow jetting means are arranged at regular intervals in a direction parallel to the rotation axis of the cylindrical substrate, and each air flow jetting means maintains a regular gap in the radial direction from the circumferential surface of the cylindrical substrate.

3. 3. The coating device according to claim 1, wherein the air jetting means further comprises means for controlling the pressure of the jetted air or the distance between the air jetting portion and the peripheral surface to which the coating material is applied.

4. 3. The coating device according to claim 1, wherein the means for moving the air jetting means in the axial direction of the cylindrical substrate further comprises means for controlling the distance and / or speed of movement of the air jetting means.

5. 3. The coating device according to claim 1, wherein the means for controlling the pressure of the sprayed airflow comprises: a determiner that determines a start point and / or an end point of the movement in conjunction with a means for moving the cylindrical substrate in the axial direction of the airflow spraying means; and a controller that stores a program that inputs information on the amount of movement of the moving means and the pressure of the airflow and executes a predetermined scan.

6. While rotating the cylindrical substrate around the axis of the cylinder as the central axis, a coating material is ejected onto the peripheral surface of the cylindrical substrate from an ejection hole of the coating material that moves linearly in the axial direction to form a coating film; Thereafter, the method includes a step of using a plurality of air flow injection means that inject air flows toward a part of the circumferential surface of the cylindrical substrate while rotating the cylindrical substrate at a rotation speed different from the rotation speed during coating, and injecting the air flows while linearly moving the plurality of air flow injection means in the axial direction of the cylindrical substrate, The step of spraying the airflow is characterized in that a plurality of airflow spraying means are arranged at regular intervals in the axial direction, and the plurality of airflow spraying means move linearly in the axial direction at the same speed while simultaneously spraying airflows, thereby spraying the airflow over the entire peripheral surface to be coated with the coating material.

7. 7. The method for forming a coating film according to claim 6, wherein the plurality of air flow injection means are air nozzles that inject air flows from injection holes, and the plurality of air flow injection means move in the axial direction at a constant moving speed while injecting air flows at a constant supply pressure or a constant flow rate, and before stopping their movement, the air supply pressure or flow rate is continuously reduced from the constant supply pressure or constant flow rate.

8. 7. The method for forming a coating film according to claim 6, wherein the plurality of air flow injection means are air nozzles which inject air flows from injection holes, and the plurality of air flow injection means move in the axial direction at a constant speed while injecting air flows at a constant supply pressure, and the speed of movement is continuously increased from the constant speed of movement before stopping.

9. A method for producing a waterless lithographic printing plate precursor, comprising forming a coating film made of a silicone material on the peripheral surface of a cylindrical substrate by using the coating film forming method according to any one of claims 6 to 8.

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