JP3542081B2 - Ink-jet coating equipment for building boards - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention of this application relates to an inkjet coating apparatus for building boards. More specifically, the invention of this application is intended to constantly flow ink during inkjet coating, to prevent the pigment component in the ink from settling, and to maintain a high-design coating with a natural feeling on the building substrate. The present invention relates to an inkjet coating apparatus.
[0002]
[Prior art]
BACKGROUND ART As a building exterior material such as an outer wall material, a roof material, and a fence material, an inorganic building board such as a cement board is widely used. The architectural board used as the building exterior material is responsible for forming the appearance of the building, and therefore, technical studies have been made on surface makeup for realizing various designs. For example, it is a common practice to apply a concavo-convex pattern to the surface of an architectural substrate formed by papermaking, extrusion, or the like by press molding, and then to paint the concavo-convex surface.
[0003]
As one method of coating, recently, ink jet coating in which ink is jetted toward the surface of a building substrate has been considered. When ink is applied to an architectural substrate on which a base color coating has been performed by ink-jet printing, a pattern of a local and controlled predetermined pattern is formed on the architectural substrate, as compared with a conventionally used coating roll. Therefore, there is an advantage that a high-design painted building board with a natural texture can be manufactured by shading.
[0004]
[Problems to be solved by the invention]
However, it is difficult to secure the storage stability of the ink in the inkjet coating of a building substrate, and the pigment component, which is a solid component in the ink, tends to settle in the ink supply path. As a result, there is a problem that ink ejection ports such as nozzles for ejecting ink are clogged, and it is difficult to maintain a high coating quality.
[0005]
The invention of this application has been made in view of such circumstances, and always allows the ink to flow during ink-jet coating, prevents the pigment component in the ink from settling, and provides a high-quality natural design to the architectural substrate. An object of the present invention is to provide an inkjet coating apparatus for a building substrate that can maintain the coating.
[0006]
[Means for Solving the Problems]
The invention of this application solves the above-mentioned problems, and a pump is provided in an ink supply path that connects an ink reservoir that stores ink and an ink chamber that ejects ink toward a building substrate, and a pump is provided. A first ink return path is provided in the ink reservoir from the ink reservoir, a second ink return path is provided from the ink chamber to the ink reservoir , and a pressure gauge for measuring ink pressure in the ink chamber is provided. The return path is provided with a flow adjustment valve that can adjust the opening, and a control unit that automatically adjusts the opening of the flow adjustment valve in accordance with the ink pressure measured by the pressure gauge is provided . The ink taken out of the ink reservoir by operation is supplied to the ink chamber in a pressurized state and filled with the ink supplied to the ink chamber, while the ink taken out of the ink reservoir is supplied. A part of the ink is returned to the ink reservoir through the first ink return path without supplying a part of the ink to the ink chamber, and a part of the ink supplied to the ink chamber is returned to the ink reservoir through the second ink return path. circulation to flow, also, the ink pressure in the ink jet coating, architectural substrates characterized that you automatically optimizes ink return pressure to the ink reservoir from an ink chamber to allow always circulating fluidized ink jet A coating device (claim 1) is provided.
[0007]
The invention of this application, 0.02～0.15MPa relates invention according to claim 1 above, the ink pressure of the ink chamber during coating is less than 0.2MPa than 0.03 MPa, the ink return pressure from the ink chamber to the ink reservoir (Claim 2 ) is provided as one embodiment.
[0008]
Further, the invention of this application relates to the inventions according to the first and second aspects, and provides, as an aspect, an aspect in which the amount of ink returned from the pump to the ink storage unit is 0.5 to 5 L / min (claim 3 ).
[0009]
Hereinafter, the inkjet coating apparatus for building boards of the present invention will be described in more detail with reference to the drawings.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a configuration diagram schematically showing an embodiment of an inkjet coating apparatus for building boards according to the present invention.
[0011]
For example, as shown in FIG. 1, the ink jet coating apparatus for building boards according to the invention of the present application includes an ink storing section (3) for storing ink (1), for example, a tank (2). A pump (7) is provided in an ink supply path (6) connecting the ink chamber (5) for ejecting the ink (1) toward the building substrate (4), and the pump (7) to the tank (2). A first ink return path (8) is provided in the ink storage section (3), and a second ink return path (9) is provided from the ink chamber (5) to the ink storage section (3).
[0012]
In the ink jet coating apparatus for building boards according to the invention of this application, the ink (1) taken out of the ink storage section (3) by the operation of the pump (7) during the ink jet coating of the building board (4) is stored in the ink chamber (5). While the ink chamber (5) is filled with the supplied ink (1), while a part of the ink (1) taken out from the ink reservoir (3) is not supplied to the ink chamber (5). A part of the ink (1) returned to the ink reservoir (3) through the first ink return path (8) and supplied to the ink chamber (5) through the second ink return path (9). Return to (3).
[0013]
Therefore, the ink jet coating apparatus for a building substrate according to the invention of the present application always circulates and flows the ink (1) during the ink jet coating of the building board (4). It is possible to prevent sedimentation in any of the above-mentioned portions, and it is possible to maintain a natural and high-design paint on the building substrate (4).
[0014]
Specifically, as shown in FIG. 1, the ink jet coating apparatus for building boards of the present invention is provided with a pressure gauge (10) for measuring the ink pressure in the ink chamber (5). A control unit that is provided with a flow control valve (11) capable of adjusting the opening in the ink return path (9) and automatically adjusts the opening of the flow control valve (11) according to the ink pressure measured by the pressure gauge (10). is Ru provided. This automatically optimizes the ink return pressure from the ink chamber (5) to the ink storage section (3), which enables the ink (1) to constantly circulate and flow, together with the ink pressure during ink-jet coating. Can be.
[0015]
Generally, it is preferable that the ink pressure in the ink chamber (5) at the time of ink-jet coating be 0.03 MPa or more and less than 0.2 MPa. If the ink pressure is less than 0.03 MPa, the ejection pressure of the ink (1) is too low, and if it exceeds 0.2 MPa, the ejection pressure of the ink (1) is too high. Painting is no longer possible.
[0016]
Further, the pressure at which the ink is returned from the ink chamber (5) to the ink storage section (3) is preferably set to 0.02 to 0.15 MPa. This range corresponds to approximately 10% to 50% of the ink supply pressure to the ink chamber (5) by the pump (7), and within this range, the ink (1) is used for the ink chamber (5) and the second ink. It flows without staying in the return path (9), and sedimentation of the pigment component can be prevented.
[0017]
As described above, the control unit automatically adjusts the opening of the flow control valve (11) according to the ink pressure measured by the pressure gauge (10). For this, an electric signal can be used, for example. That is, the measured ink pressure is converted into an electric signal by the pressure gauge (10), and the electric signal is input to the control unit. Data relating to the ink pressure and the ink return pressure from the ink chamber (5) to the ink storage section (3) is set, and based on this data, the optimal opening is automatically output to the flow rate control valve (11). Is exemplified.
[0019]
In the ink jet coating apparatus for building boards according to the present invention, the amount of ink returned from the pump (7) to the ink storage section (3) via the first ink return path (8) is generally equal to the amount of ink returned. It is preferably 0.5 to 5 L / min. If the amount of ink returned is less than 0.5 L / min, it is not very effective for sedimentation of the pigment component in the ink. If it exceeds 5 L / min, the amount of ink supplied to the ink chamber (5) becomes insufficient. Become. The control unit can also be used to adjust the amount of ink returned from the pump (7) to the ink storage unit (3).
[0020]
That is, as shown in FIG. 1, a flow control valve (12) capable of adjusting the opening similar to the flow control valve (11) is provided in each of the ink supply path (6) and the first ink return path (8). Can be arranged, and the opening degree can be automatically adjusted by the control unit.
[0021]
Furthermore, as shown in FIG. 1, the ink jet coating apparatus for building boards according to the invention of this application is provided with a filter (13) at the tip of an ink supply path (6) to supply ink () to an ink chamber (5). In order to maintain the quality of 1), a stirrer (14) is provided in an ink storage unit (3) such as a tank (2) to prevent the ink (1) from staying in the ink storage unit (3) during inkjet coating. It can also be prevented.
[0022]
Furthermore, the ink jet coating apparatus for building boards according to the invention of the present application can be provided with a tank (15) or the like so that the inside of the apparatus can be washed when changing the coating color of the building board (4). A cleaning liquid reservoir (17) for storing the cleaning liquid (16) is provided, the cleaning liquid supply path (18) is connected to the ink supply path (6) on the upstream side of the pump (7), and the cleaning liquid return path (19) is connected to the second. It can be connected to the ink return path (9). In addition to the cleaning liquid supply path (18) and the cleaning liquid return path (19), the second ink downstream of the connection with the ink supply path (6) and the cleaning liquid return path (19) upstream of the pump (7). A valve (20) can be provided in the return path (9). During cleaning, the valves (20) provided in the cleaning liquid supply path (18) and the cleaning liquid return path (19) are opened, and the other valves (20) are closed. During the inkjet coating, the valves (20) provided in the ink supply path (6) and the second ink return path (9) are opened, and the other valves (20) are closed. Opening and closing of such valves (20), similar to the above-described flow regulating valve (11) (12), it can be an automated control by the control unit.
[0023]
A filter (21) is also provided at the end of the cleaning liquid supply path (18), and the cleaning liquid (16) can be circulated during cleaning to clean the inside of the apparatus.
[0024]
The inkjet coating apparatus for a building substrate of the invention of the present application described above can perform the inkjet coating of the building board (4) under the following conditions, for example.
[1] Architectural substrate temperature The architectural substrate (4) is intended to be a substrate which has been pre-colored, but the substrate temperature is preferably set to 40 to 70 ° C. in ink-jet coating. If the substrate temperature is lower than 40 ° C., the evaporation rate of the solvent in the ink is slow, and the pigment component tends to be unbalanced, making it difficult to achieve a high-design coating. The upper limit of 70 ° C. is in consideration of the energy and cost required for heating the substrate.
[2] The diameter of the ink ejection port (22) provided in the lower surface portion of the ink chamber (5), which can be an ink ejection port nozzle or the like, is 80 to 350 μm. preferable. When the diameter is less than 80 μm, the pigment component in the ink (1) tends to clog the ink ejection port (22) even if the ink (1) is constantly circulated and flowed during ink jet coating. If the diameter exceeds 350 μm, the amount of ejected ink increases, the resolution of coating decreases, and it becomes difficult to achieve high-quality coating.
[3] Ink ejection amount The ink ejection amount is preferably 0.2 to 1.0 mg, and more preferably 0.35 to 0.6 mg per time. When the ink ejection amount is less than 0.2 mg per time, an ink ejection device including a piston (23) provided in the ink chamber (5) shown in FIG. High-speed operation is required, and the parts of the piston (23) and the surroundings of the ink ejecting device are greatly worn and worn, so that long-term reliability of the operation of the coating device may not be obtained. If the amount of ink ejected exceeds 1.0 mg per time, the amount of ink ejected is large, and the resolution of the coating is reduced, making it difficult to achieve highly designed coating.
[4] Ink Jet Port Interval The interval between the ink jet ports (22) is preferably 2 to 7 mm, more preferably 3 to 5 mm. When the interval between the ink ejection ports (22) is less than 2 mm, the ejection amount of the ink (1) becomes very small due to the small interval, and the ink ejection device including the piston (23) as described above operates at high speed. The adverse effects are caused by this. If the distance between the ink ejection ports (22) exceeds 7 mm, the amount of ink to be ejected increases, and the resolution of coating decreases, making it difficult to achieve high-design coating.
[5] Distance between Ink Jet Port and Building Board The distance between the ink jet port (22) and the building board (4) is increased up to 70 mm by the ink jet coating apparatus for building board of the present invention. be able to. In the conventional ink jet coating apparatus, it has generally been necessary to set the thickness within 5 mm. By increasing the distance between the ink ejection port (22) and the building board (4) in this way, clogging of the ink ejection port (22) due to heat radiation of the building board (4) is also eliminated.
[6] Injection interval of ink The shading expression of the ink (1) in the inkjet coating of the building substrate (4) can be realized by changing the overlapping width of the dots of the ink (1). That is, if the overlapping width of the dots is large, the dot becomes dark, and if the dot is small, the dot becomes thin. Therefore, for example, if it is desired to reduce the thickness, the ejection interval of the ink (1) is adjusted so that the overlapping width of the dots is 10% or less, and if it is desired to increase the density, the overlapping width of the dots is 80% or more. Adjust to In the case of expressing the middle, adjustment is made so that the overlap width is 50 to 30%. In this way, the monochromatic ink (1) enables natural shade expression.
[0025]
Of course, the invention of this application is not limited by the above embodiments. It goes without saying that various aspects are possible for details such as the configuration and structure of the ink storage section, the ink chamber, the pressure gauge, the flow control valve, the control section, and the like.
[0026]
【The invention's effect】
As described in detail above, according to the invention of this application, the ink constantly circulates and flows in the apparatus during inkjet coating, the pigment component in the ink does not settle, and it is possible to maintain a high-design coating with a natural feeling on the building substrate. . Further, it is possible to automatically optimize the pressure for returning the ink from the ink chamber to the ink storing section, which enables the ink to constantly circulate and flow, together with the ink pressure at the time of inkjet coating.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing an embodiment of an inkjet coating apparatus for building boards according to the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Ink 2 Tank 3 Ink storage unit 4 Building substrate 5 Ink chamber 6 Ink supply path 7 Pump 8 First ink return path 9 Second ink return path 10 Pressure gauge 11 Flow control valve 12 Flow control valve 13 Filter 14 Stirrer 15 Tank 16 Cleaning liquid 17 Cleaning liquid storage section 18 Cleaning liquid supply path 19 Cleaning liquid return path 20 Valve 21 Filter 22 Ink ejection port 23 Piston

Claims (3)

A pump is provided in an ink supply path that connects an ink storage section that stores ink and an ink chamber that ejects ink toward a building substrate, and a first ink return path is provided from the pump to the ink storage section. A second ink return path is provided from the ink chamber to the ink storage unit, a pressure gauge for measuring the ink pressure in the ink chamber is provided, and a flow control valve capable of adjusting the opening degree is provided in the second ink return path, A control unit is provided to automatically adjust the opening of the flow control valve in accordance with the ink pressure measured by the pressure gauge. During ink- jet coating of a building board, the pump is operated to pump ink from the ink storage unit into the ink chamber. And the ink chamber is filled with the supplied ink, and a part of the ink taken out from the ink storage unit is not supplied to the ink chamber, but is supplied through the first ink return path. Back to the ink reservoir, and returns a portion of the ink supplied to the ink chamber to the ink reservoir through the second ink return path, ink is continuously circulated flowing, also the ink pressure in the ink jet coating, ink constantly circulating fluidized possible to ink chamber automatically optimized to the inkjet coating apparatus of the building board, characterized in Rukoto ink return pressure to the ink reservoir from. The ink jet coating apparatus for building boards according to claim 1 , wherein the ink pressure in the ink chamber at the time of coating is 0.03MPa or more and less than 0.2MPa, and the ink return pressure from the ink chamber to the ink storage section is 0.02 to 0.15MPa . The ink jet coating apparatus for building boards according to claim 1 or 2, wherein the amount of ink returned from the pump to the ink storage unit is 0.5 to 5 L / min .

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