JP7522846B2 - Coating device and inkjet printing device - Google Patents

Description

The present invention relates to an application device and an inkjet printing device.

To achieve high-quality inkjet printing, it is necessary to apply an acidic undercoat liquid thinly and uniformly to the substrate in order to quickly fix the dots of water-based ink to the substrate. Uneven application of the undercoat liquid to the substrate can induce uneven density, which can be one of the factors that cause the image quality of the printed image to look unnatural. Here, "fast fixation" means fixation in a short period of time.

On the other hand, in recent years, there has been an increasing demand for diversifying printing products and producing smaller lots, and printing conditions such as printing speed and substrate conditions are often changed during the course of a day's printing work. Here, printing speed refers to the time required for each printed sheet, and a fast printing speed means that the time required for each printed sheet is relatively short. In addition, the term speed in this specification can include the meaning of speed that represents the scalar quantity of speed.

Examples of substrate conditions include the type of substrate, including the material of the substrate and the size of the substrate. The size of the substrate refers to the length of the substrate in the width direction and the thickness of the substrate. The width of the substrate refers to the direction perpendicular to the direction in which the substrate is transported.

The coating device is required to maintain a uniform coating amount under various printing conditions. In order to meet the requirement of uniform coating, it is preferable that the coating device is configured so that the parameters that control the coating amount can be easily changed. For example, it is preferable that the metering roller, which has a direct effect on the coating amount, has a configuration in which the volume of the cells and grooves that measure the coating liquid can be easily changed.

On the other hand, in gravure-type coating devices such as gravure coaters and kiss reverse coaters, which use a gravure roll to measure the coating liquid, it is not easy to replace the heavy gravure roll, and replacing the gravure roll is time-consuming.

In addition, compared to other types, the gravure type coating device has limited parameters for controlling the coating amount. Furthermore, when the width of the substrate is changed, the gravure type coating device needs to replace the gravure roll or the like that does not correspond to the substrate width with a gravure roll or the like that corresponds to the substrate width. In this case, compared to other types, the gravure type coating device requires more effort to replace the gravure roll or the like, and has a problem with suitability for switching substrate widths.

Furthermore, most gravure-type coating devices are configured to scrape off excess coating liquid from the gravure roll using a blade or similar, and there is an issue that when at least one of the gravure roll and the blade etc. wears to a certain extent, the amount of coating fluctuates.

In a bar coating type coating device equipped with a bar coater, the bar coater is extremely lightweight compared to a gravure roll, and the bar coater can be easily replaced. In addition, there are a wide variety of parameters for controlling the coating amount, such as the type of bar coater, and it is advantageous in terms of control parameters compared to other coating methods. In addition, a bar coating type coating device is bladeless, which means there is no need to scrape off the coating liquid applied to the bar coater, and there is no concern about fluctuations in the coating amount due to wear on the bar coater.

In other words, a bar coating type coating device can easily switch printing conditions such as printing speed and substrate conditions during a day's printing work, and can carry out printing work under various printing conditions in response to user requests while minimizing loss of work time.

Patent Document 1 describes a coating device that uses a bar coating method. The device described in the document is equipped with a coating bar that has a cylindrical bar surface on which multiple spiral grooves are formed, and the coating liquid is applied to the web by continuously running the web, which is the member to be coated, and bringing the coating bar into contact with the web.

Patent document 2 describes an application device equipped with a wire bar with a wire wound around a core. In the device described in the document, the rotating wire bar is brought into contact with a traveling web, and the coating liquid is applied from the wire bar to the web.

JP 2009-226371 A JP 2006-82059 A

However, in a coating device using the bar coating method, the coating liquid is interposed between the bar coater and the bar support seat, and the bar support seat can absorb the coating liquid and cause the bar support seat to expand. This can cause frictional resistance between the bar coater and the bar support seat.

Furthermore, wear on the bar support seat can cause the bar coater to wobble when the bar member is rotated. Wobbling of the bar coater when it is rotated can cause frictional resistance between the bar coater and the bar support seat.

In other words, the frictional resistance generated between the bar coater and the bar support seat can cause wear of the bar coater. The device described in Patent Document 1 and the device described in Patent Document 2 have the above-mentioned problems with the bar coating method.

The present invention has been made in consideration of the above circumstances, and aims to provide an application device and an inkjet printing device that can suppress wear on the bar members in a bar application type application device.

In order to achieve the above objective, the following aspects of the invention are provided:

The coating device according to the present disclosure is a cylindrical bar member supported rotatably about a central axis, the bar member rotating about the central axis and contacting the substrate to apply a coating liquid containing water to the substrate, and a bar support member rotatably supporting the bar member, the bar support member storing the coating liquid to be supplied to the bar member, and a bar opposing portion of the bar support member opposing the bar member is a coating device to which a material having a water absorption rate of 0.05 percent or less and a Shore hardness of D60 or more is applied.

The coating device according to the present disclosure suppresses swelling of the bar support member caused by absorption of the coating liquid and wobble caused by wear of the bar support member during rotation of the bar member. This can suppress frictional resistance generated between the bar member and the bar support member.

The bar receiving member may be entirely made of the material applied to the bar opposing portion.

In another embodiment of the coating device, the bar opposing portion is made of a material having a surface free energy of 33 millinewtons per meter or less.

According to this aspect, the shear stress on the bar member and the bar receiving member is reduced, and wear on the bar member and the bar receiving member is suppressed.

In another aspect of the coating device, the bar member has a mass per meter of 0.5 kilograms or more and 3.0 kilograms or less.

This aspect makes it possible to achieve both easy replacement of the bar member and suppression of vibration when the bar member rotates.

In another aspect of the coating device, the bar member has a spiral protrusion formed on the side.

According to this aspect, the coating liquid moves along the non-convex portions between adjacent convex portions, thereby preventing the substances contained in the coating liquid from clogging the non-convex portions.

An example of such a bar member is a wire bar having a structure in which a wire is wound in a spiral shape on the side of a substrate.

In another embodiment of the coating device, when the length of the convex portion of the bar member is A and the length of the non-convex portion is B in a direction parallel to the central axis, the length A of the convex portion and the length B of the non-convex portion satisfy B/A≦1.

According to this aspect, unevenness in the thickness of the coating liquid when it is transferred from the bar member to the substrate is suppressed, and the thickness of the coating liquid applied to the substrate can be made uniform.

It is preferable that the non-convex portion is a flat surface having a certain area.

In another aspect of the coating device, a spiral recess is formed on the side of the bar member.

According to this aspect, the coating liquid moves along the recess, and clogging of the recess with substances contained in the coating liquid is suppressed.

An example of such a bar member is a wireless bar in which a spiral groove is formed on the side of the substrate.

In another embodiment of the coating device, when the length of the non-recessed portion of the bar member is A and the length of the recessed portion is B in a direction parallel to the central axis, the length A of the non-recessed portion and the length B of the recessed portion satisfy B/A≦1.

According to this aspect, unevenness in the thickness of the coating liquid when it is transferred from the bar member to the substrate is suppressed, and the thickness of the coating liquid applied to the substrate can be made uniform.

It is preferable that the bottom surface of the recess be a flat surface having a certain area.

In another aspect of the coating device, a conveying device is provided that supports and conveys the substrate, and the conveying device is provided with a moving mechanism that moves the position of the substrate in a direction having a vertical component.

According to this aspect, there is no need for a backup roller that is replaced when changing the size of the substrate, making it easy to switch the coating device according to the size of the substrate.

In another embodiment of the coating device, the coating device is provided with a liquid storage section in which the coating liquid to be applied to the bar member is stored, and a recovery section in which the coating liquid that overflows from the liquid storage section is recovered.

According to this embodiment, the coating liquid is circulated and fresh coating liquid is supplied. This can prevent adhesion between the bar member and the bar receiving member caused by high viscosity of the coating liquid, etc.

A latex with a relatively low glass transition point can be added to the coating liquid, making it possible to achieve both adhesion of the coating liquid to the substrate and application stability of the coating liquid to the substrate.

In another aspect of the coating device, the liquid storage section is provided at least in one of the upstream and downstream positions of the bar member in the substrate transport direction, and the recovery section is provided corresponding to the position where the liquid storage section is provided.

According to this embodiment, the excess coating liquid moves from the storage section to the recovery section. This can promote circulation of the coating liquid.

In another embodiment, the coating device is provided with one or more processors and one or more memories, and the processor acquires coating conditions for applying the coating liquid to the substrate, reads parameters stored in the memory according to the coating conditions, and controls the application of the coating liquid to the substrate based on the read parameters.

According to this aspect, parameters can be set according to the application conditions.

In another embodiment of the coating device, the coating liquid contains 0.1 mass percent or more of a surfactant.

According to this aspect, the lubricity of the coating liquid against the bar member and the bar receiving member can be improved.

In another embodiment of the coating device, the coating liquid contains latex.

According to this aspect, the surfactant is more easily adsorbed around the latex dispersed in the coating liquid, and the lubricity of the coating liquid relative to the bar member and the bar receiving member can be improved.

In another embodiment of the coating device, the coating liquid contains latex having an average particle diameter of 30 nanometers or more and 500 nanometers or less.

According to this aspect, the cleaning suitability of the bar member can be improved.

The inkjet printing apparatus according to the present disclosure comprises an application device that applies a coating liquid that aggregates ink to a print medium, and an inkjet head that ejects ink onto the print medium to which the coating liquid is applied, the application device being a bar member that has a cylindrical shape and is supported rotatably about a central axis, the bar member rotating about the central axis and applying a coating liquid containing water to the print medium by coming into contact with the print medium , and a bar support member that rotatably supports the bar member, and the bar support member stores the coating liquid to be supplied to the bar member, and the bar opposing portion of the bar support member that faces the bar member is made of a material having a water absorption rate of 0.05 percent or less and a Shore hardness of D60 or more.

According to the inkjet printing device of the present disclosure, it is possible to obtain the same action and effect as the coating device of the present disclosure. The constituent elements of the coating device of other aspects may be applied to the constituent elements of the inkjet printing device of other aspects.

According to the present invention, the swelling of the bar receiving member caused by the absorption of the coating liquid and the wobbling of the bar member caused by the wear of the bar receiving member during rotation are suppressed. This makes it possible to suppress the frictional resistance generated between the bar member and the bar receiving member.

FIG. 1 is a diagram showing the overall configuration of a coating apparatus according to an embodiment. FIG. 2 is a functional block diagram showing the electrical configuration of the coating apparatus shown in FIG. FIG. 3 is a perspective view of the bar block shown in FIG. FIG. 4 is a schematic diagram showing the internal structure of the bar block shown in FIG. FIG. 5 is a perspective view of a wire bar coater. FIG. 6 is a perspective view of the wireless bar coater. FIG. 7 is an enlarged side view of the wireless bar coater. FIG. 8 is a table showing the results of evaluation of the abrasion of the bar coater with respect to the water absorption rate of the bar receiving portion and the hardness of the bar receiving portion. FIG. 9 is a table showing the results of evaluation of the abrasion of the bar coater relative to the surface free energy of the bar receiving portion. FIG. 10 is a table showing the results of evaluation of the abrasion of the bar coater versus the amount of surfactant added. FIG. 11 is a table illustrating the difference in effect between the bar coating method and other coating methods. FIG. 12 is a diagram showing the overall configuration of an inkjet printing apparatus to which the coating device according to this embodiment is applied. FIG. 13 is a table showing examples of compositions of precoat liquids according to other specific examples. FIG. 14 is a table showing other composition examples of the precoat liquid according to another embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. In this specification, the same components are given the same reference symbols, and duplicate explanations will be omitted as appropriate.

[Coating device according to embodiment]
〔overall structure〕
1 is an overall configuration diagram of a coating apparatus according to an embodiment. The coating apparatus 10 shown in the figure includes a bar coating device 12 that ejects a coating liquid, and a transport device 14 that transports a substrate S. The coating apparatus 10 supplies a coating liquid from a coating liquid supply device 50 to a bar coater 22 provided in a bar block 20 of the bar coating device 12, brings the substrate S into contact with the bar coater 22, and coats the substrate S with the coating liquid.

In addition, contact between the substrate S and the bar coater 22 includes a state in which the coating liquid is ejected from the bar coater 22 and the coating liquid is present between the substrate S and the bar coater 22.

[Example of the configuration of a bar coating device]
The bar coating device 12 includes a bar block 20, a base 40, and a coating liquid supply device 50. The bar block 20 includes a bar coater 22 and a bar support portion 24. Details of the bar block 20 will be described later. The bar coater 22 described in the embodiment is an example of a bar member.

The bar coater 22 is supported rotatably and removably using a bar support mechanism provided in the bar support section 24. The bar coater 22 is connected to a bar drive device. The bar drive device includes a motor that serves as the drive source for the bar coater 22, and a mechanical mechanism that connects the motor's rotation shaft to the bar coater 22. The bar drive device is not shown in Figure 1. The bar drive device is shown in Figure 2 and is designated by the reference numeral 114.

The bar support mechanism that supports the bar coaters 22 has a support structure for the bar coaters 22 that corresponds to a plurality of bar coaters 22 having different effective coating lengths in the longitudinal direction corresponding to the width of the substrate S. The coating device 10 can apply bar coaters 22 that correspond to coating conditions such as the width of the substrate S. The bar support mechanism is not shown in the figure.

The bar block 20 is supported by a base 40. The base 40 is equipped with a mechanism for adjusting the horizontality, which represents the angle with respect to the horizontal plane, for the width direction of the substrate S. The width direction of the substrate S is a direction perpendicular to the transport direction of the substrate S and parallel to the coating surface of the substrate S with the coating liquid.

Hereinafter, the width direction of the substrate S may be referred to as the substrate width direction, and the transport direction of the substrate S may be referred to as the substrate transport direction. The substrate width direction is the direction penetrating the paper surface of Figure 1. In Figure 1, the symbol y is used to represent the substrate transport direction. The symbol z is used to represent the vertical direction.

The angle of the base 40 of the bar block 20 relative to the horizontal plane is adjusted to bring the bar coater 22 into contact with the substrate S in parallel. This can suppress variations in the lap width and the pressure between the coating liquid and the substrate S, which are caused by uneven contact of the substrate S with the bar coater 22. The lap width is the length of the area where the substrate S and the bar coater 22 are in contact in the substrate width direction.

The bar block 20 is periodically subjected to maintenance such as cleaning and part replacement. When performing maintenance on the bar block 20, the bar block 20 is removed from the base 40. After maintenance has been performed on the bar block 20, it is attached back to the base 40.

That is, the base 40 is configured to allow the bar block 20 to be attached and detached. The base 40 also employs a structure that allows for high reproducibility of the placement position of the bar block 20. This achieves both improved maintenance efficiency of the bar block 20 and maintenance of application performance before and after maintenance.

The coating liquid supply device 50 includes a supply flow path 52, a liquid delivery pump 54, and a coating liquid tank 56. The coating liquid stored in the coating liquid tank 56 is supplied to the bar block 20 via the liquid delivery pump 54 and the supply flow path 52.

The coating liquid supply device 50 controls the amount of liquid delivered to the bar block 20, enabling precise control of the amount of coating liquid applied to the bar coater 22. It is preferable that the liquid delivery pump 54 be of a type that suppresses pulsation during delivery.

The coating liquid supply device 50 also includes a circulation flow path 57, a circulation pump 58, and a recovery tank 59. The coating liquid discharged from the bar block 20 is recovered in the recovery tank 59 via the circulation flow path 57 and the circulation pump 58. As with the liquid delivery pump 54, the circulation pump 58 is preferably of a type that suppresses pulsation during liquid delivery.

The coating liquid collected in the collection tank 59 may be returned to the coating liquid tank 56 and supplied to the bar block 20. The flow path connecting the collection tank 59 and the coating liquid tank 56 may be equipped with a filter, a concentration meter, etc.

[Example of the configuration of the transport device]
The conveying device 14 conveys the substrate S along the substrate conveying direction. The conveying device 14 includes a conveying mechanism 60 and a lifting device 68. Fig. 1 illustrates a continuum to which a roll-to-roll conveyance method is applied as an example of the substrate S. Note that Fig. 1 omits the illustration of the roll on the unwinding side of the substrate S and the roll on the winding side of the substrate S.

The transport mechanism 60 includes a first lift roller 62, a second lift roller 64, and a drive roller 66. A motor is connected to the drive roller 66. The drive roller 66 rotates in response to the operation of the motor to support the substrate S and transport the substrate S.

The conveying mechanism 60 includes one or more support rollers. The support rollers are arranged at any position on the substrate conveying path in the conveying mechanism 60 and support the substrate S on the substrate conveying path. Note that the support rollers are not shown in the figure.

The first lift roller 62 and the second lift roller 64 support the substrate S in the area where the coating liquid is applied from the bar block 20 to the substrate S, and adjust the size of the wrap angle of the substrate S relative to the bar coater 22 and the distance between the substrate S and the bar coater 22.

The first lift roller 62 and the second lift roller 64 are configured to be able to move independently. The arrow line attached to the first lift roller 62 indicates the movement direction of the first lift roller 62 and the direction of the pressing force applied to the substrate S by the first lift roller 62. The first lift roller 62 can move in the substrate transport direction and the vertical direction.

The arrow line on the second lift roller 64 indicates the movement direction of the second lift roller 64 and the direction of the pressing force applied to the substrate S by the second lift roller 64. The second lift roller 64 can move in the substrate conveying direction and the vertical direction, similar to the first lift roller 62.

The size of the wrap angle of the substrate S relative to the bar coater 22 can be adjusted separately for the primary side and secondary side of the bar coater 22. The same applies to the distance between the substrate S and the bar coater 22. Here, the primary side is the upstream side of the substrate transport direction in the bar coater 22, and is the left side of the bar coater 22 in Figure 1. The secondary side is the downstream side of the substrate transport direction in the bar coater 22, and is the right side of the bar coater 22 in the same figure.

The wrap angle of the substrate S relative to the bar coater 22 is preferably in the range of 2.0 degrees or more and 30 degrees or less. If the wrap angle of the substrate S relative to the bar coater 22 is less than 2.0 degrees, the contact surface between the bar coater 22 and the substrate S is unstable, and uneven application of the coating liquid on the substrate S may occur.

Furthermore, if the wrap angle of the substrate S relative to the bar coater 22 exceeds 30 degrees, uneven coating of the coating liquid on the substrate S may occur due to the frictional force generated between the bar coater 22 and the substrate S. A more preferred range for the wrap angle of the substrate S relative to the bar coater 22 is 5.0 degrees or more and 20 degrees or less.

The tension applied to the substrate S when it is transported is preferably 10 to 200 newtons per meter. If the tension applied to the substrate S per meter is less than 10 newtons, wrinkles may occur on the substrate S, resulting in uneven application of the coating liquid.

On the other hand, if the tension applied per meter of the substrate S exceeds 200 Newtons, unevenness in the coating liquid may occur due to the frictional force between the tip of the bar block 20 and the substrate S.

If the condition of the substrate S differs in the substrate width direction, a distribution of tension is applied to the substrate S in the substrate width direction at the position where the substrate S contacts the bar coater 22, which may result in uneven application of the coating liquid in the substrate width direction.

A preferred embodiment is one in which a heat roller is provided upstream of the bar coater 22 in the substrate transport direction, to uniformize the condition of the substrate S in the substrate width direction and suppress uneven application of the coating liquid in the substrate width direction.

The heat roller has a cylindrical shape and a length in the width direction of the substrate that corresponds to the length of the substrate S. The heat roller incorporates a heat source such as a heater and supplies heat emitted from the heat source to the substrate S. The heat roller applies a certain tension to the substrate S when it comes into contact with the substrate S, smoothing the substrate S.

The lifting device 68 moves the transport mechanism 60 in the vertical direction to adjust the vertical distance between the substrate S and the bar block 20. When applying the coating liquid to the substrate S, the lifting device 68 lowers the transport mechanism 60 to bring the substrate S into contact with the bar coater 22. On the other hand, when the substrate S is not being coated with the coating liquid, the lifting device 68 raises the transport mechanism 60 to move the substrate S away from the bar coater 22.

[Electrical configuration of the coating device]
Fig. 2 is a functional block diagram showing the electrical configuration of the coating apparatus shown in Fig. 1. The coating apparatus 10 includes one or more processors 100 and one or more memories 102.

The processor 100 includes a conveying control unit 110, a lifting control unit 112, a bar drive control unit 113, a pump control unit 115, a coating condition acquisition unit 117, and a parameter setting unit 118. Each unit included in the processor 100 corresponds to a function of the coating device 10 realized using the processor 100.

The transport control unit 110 sends a command signal to the transport mechanism 60, controls the operation of the transport mechanism 60, and controls the transport of the substrate S. The transport control unit 110 controls the operation of a motor connected to a drive roller 66 provided in the transport mechanism 60. The transport control unit 110 controls the operation of a motor connected to a lift roller moving mechanism that moves the first lift roller 62 and the second lift roller 64. The transport control unit 110 also controls the unwinding of the substrate S and the winding of the substrate S.

The lift control unit 112 sends a command signal to the lift device 68 and controls the operation of the lift device 68. At the start of the application period of the coating liquid, the lift control unit 112 lowers the transport mechanism 60 from the retracted position and moves the transport mechanism 60 to the application position. At the end of the application period of the coating liquid, the lift control unit 112 raises the transport mechanism 60 from the application position and moves the transport mechanism 60 to the retracted position.

The bar drive control unit 113 transmits a command signal to the bar drive device 114 and controls the operation of the bar drive device 114. The bar drive control unit 113 can set the rotation speed of the bar coater 22 according to the conveying speed of the substrate S.

The bar drive control unit 113 can adjust the speed of the side of the bar coater 22 in the substrate transport direction at the position where the bar coater 22 contacts the substrate S to a range of 5.0 percent or more and 150 percent or less of the transport speed of the substrate S.

If the speed ratio is less than 5.0 percent, friction between the bar coater 22 and the substrate S becomes relatively large, and stepped unevenness may occur in the coating liquid applied to the substrate S. If the speed ratio exceeds 150 percent, vibrations occur when the bar coater 22 rotates, which may cause uneven application of the coating liquid applied to the substrate S. It is more preferable that the speed ratio is in the range of 10 percent or more and 100 percent or less.

The bar drive control unit 113 controls the rotation direction of the bar coater 22. For example, when improving the surface condition of the coating liquid applied to the substrate S, the bar drive control unit 113 reverses the rotation of the bar coater 22.

The pump control unit 115 transmits a command signal to the pump 116 to control the operation of the pump 116. The pump 116 shown in Figure 2 represents the coating liquid tank 56 and the circulation pump 58 shown in Figure 1.

The pump control unit 115 controls the amount of coating liquid sent from the liquid delivery pump 54 to the bar block 20. The pump control unit 115 controls the amount of coating liquid sent from the bar block 20 to the circulation pump 58.

The coating condition acquisition unit 117 acquires coating conditions to be applied to the coating device 10 via the input device 130, the input/output interface 140, etc. The coating conditions may include the type of substrate S and the type of coating liquid. The type of substrate S may include the material of the substrate S and the size of the substrate S. The size of the substrate S may include the width of the substrate S and the thickness of the substrate S.

The parameter setting unit 118 sets various parameters to be applied to the coating device 10 according to the coating conditions acquired using the coating condition acquisition unit 117. Various control units such as the conveying control unit 110 control the operation of each unit based on the parameters set using the parameter setting unit 118.

The processor 100 may display various parameters set using the parameter setting unit 118 on the display device 120.

The memory 102 includes a parameter storage unit 104. The parameter storage unit 104 stores various parameters to be applied to the coating device 10. Examples of the various parameters include the rotation speed of the bar coater 22, the discharge amount per unit time of the liquid delivery pump 54, and the tension applied to the substrate S from the first lift roller 62, etc.

The parameter setting unit 118 reads and sets various parameters according to the application conditions from the parameter memory unit 104.

The memory 102 stores various programs executed by the processor 100. The memory 102 may store various data. The memory 102 may be applied to the area of calculations executed by the processor 100.

The coating device 10 includes a display device 120 and an input device 130. The display device 120 displays various information applied to the coating device 10 based on a display signal transmitted from a display driver 122.

The input device 130 may be a keyboard, a mouse, or the like. The input device 130 transmits an input signal corresponding to a user's operation to the processor 100. The processor 100 performs various processes corresponding to the input signal. The display device 120 and the input device 130 may be integrated using a touch panel type display device 120.

The coating device 10 includes an input/output interface 140. The input/output interface 140 may be compatible with various communication standards such as Universal Serial Bus (USB). The coating device 10 may include an input/output interface 140 for each of a plurality of communication standards.

[Hardware configuration of various processing units and various control units]
The hardware of the processing unit that performs various processes may be implemented using various processors. The processing unit may be called a processing unit. The various processors include a central processing unit (CPU), a programmable logic device (PLD), and an application specific integrated circuit (ASIC).

A CPU is a general-purpose processor that executes programs and functions as various processing units. A PLD is a processor whose circuit configuration can be changed after manufacture. An example of a PLD is an FPGA (Field Programmable Gate Array). An ASIC is a dedicated electrical circuit with a circuit configuration designed specifically to perform specific processing.

A single processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types. For example, a single processing unit may be configured using multiple FPGAs, etc. A single processing unit may be configured by combining one or more FPGAs and one or more CPUs.

In addition, multiple processing units may be configured using one processor. One example of using one processor to configure multiple processing units is a form in which one processor is configured by combining one or more CPUs with software, and the single processor functions as multiple processing units. This form is typified by computers such as client terminal devices and server devices.

Another example of the configuration is a form that uses a processor that realizes the functions of the entire system including multiple processing units using a single IC chip. Such a form is typified by a system on chip . Note that IC is an abbreviation for Integrated Circuit. Also, a system on chip may be written as SoC, which is an abbreviation for System On Chip.

In this way, the various processing units are configured as a hardware structure using one or more of the various processors described above. Furthermore, the hardware structure of the various processors is, more specifically, an electric circuit (circuitry) that combines circuit elements such as semiconductor elements.

[Example of bar block structure]
Fig. 3 is a perspective view of the bar block shown in Fig. 1. The bar block 20 shown in the figure includes a bar coater 22 and a bar support part 24. The bar coater 22 has a cylindrical shape, and the length in the substrate width direction exceeds the length in the substrate width direction of the substrate S. The symbol x shown in the figure represents the substrate width direction.

The bar support section 24 includes a bar receiving member 26 that rotatably supports the bar coater 22 via a bearing attached to the central shaft 22A of the bar coater 22. The bearing and the mounting structure of the bearing in the bar receiving member 26 are not shown in the figure.

The bar support member 26 has a length in the substrate width direction that corresponds to the length of the bar coater 22 in the substrate width direction. The bar support member 26 supports the bar coater 22 over its entire length in the substrate width direction, limiting the deflection of the bar coater 22 to a certain range.

The bar support member 26 has a bar facing surface 26A that faces the side of the bar coater 22, and a support structure for the bar coater 22 that is not in contact with the side of the bar coater 22. The bar facing surface 26A is a curved surface that corresponds to the side of the bar coater 22.

The bar receiving member 26 supports the bar coater 22 at a position where the shortest distance from the bar facing surface 26A to the central axis 22A of the bar coater 22 exceeds the radius of the bar coater 22. The bar receiving member 26 also supports the bar coater 22 at a position where a part of the bar coater 22 is exposed. The bar facing surface 26A shown in the embodiment is an example of a bar facing portion.

Figure 4 is a schematic diagram showing the internal structure of the bar block shown in Figure 3. Figure 4 shows a cross section of the bar support section 24 in a direction parallel to the substrate transport direction. The bar support section 24 is partitioned using an upstream weir 30 and a downstream weir 32, and is provided with a liquid pool 34 in which coating liquid is stored. The bar receiving member 26 is positioned inside the liquid pool 34.

One end of a slit 36 is formed on the bottom surface 34A of the liquid pool 34. The slit 36 is connected to a supply flow path 52 shown in FIG. 1. The liquid pool 34 is supplied with the coating liquid from the supply flow path 52 via the slit 36.

The liquid pool 34 is provided with coating liquid at a position directly below the bar coater 22, which is supported by the bar support member 26. The bar coater 22 is supported at a position where it is partially immersed in the coating liquid stored in the liquid pool 34.

The liquid pool 34 has a length in the substrate width direction that is longer than the overall length of the bar coater 22 and the bar receiving member 26 in the substrate width direction. The slit 36 has a length in the substrate width direction that corresponds to the overall length of the liquid pool 34 in the substrate width direction.

Figure 4 illustrates an example in which slits 36 are formed at both the upstream and downstream positions in the substrate transport direction of the bar receiving member 26, with one end of each being formed on the bottom surface 34A of the liquid pool 34, but the structure of the slits 36 is not limited to the embodiment illustrated in Figure 4.

For example, the upstream slit 36 and the downstream slit 36 may be merged, and one end of the merged flow path may be formed at a position upstream or downstream of the bottom surface 34A of the liquid pool 34 in the substrate conveying direction of the bar receiving member 26. The liquid pool 34 described in the embodiment is an example of a liquid storage section.

The width of the slit 36 is preferably 0.5 mm or more and 5.0 mm or less. The width of the slit 36 is the length of the slit 36 in a direction parallel to the substrate transport direction. If the width of the slit 36 is less than 0.5 mm, the coating liquid is likely to clog the slit 36.

If the width of the slit 36 exceeds 5.0 mm, it is easily affected by the pulsation of the liquid delivery pump 54 shown in Figure 1. The preferred width of the slit 36 is 1.0 mm or more and 4.0 mm or less.

The slits 36 may be configured to have multiple slits arranged in a zigzag pattern that are shorter than the overall length of the bar coater 22 in the width direction of the substrate. Multiple short slits may be arranged in a zigzag pattern that corresponds to the overall length of the bar coater 22 in the width direction of the substrate. Multiple through holes may be used instead of the slits 36.

The bar support portion 24 is provided with a recovery groove 38. The recovery groove 38 is disposed at the position of the upstream weir 30 in the substrate transport direction and at a position downstream of the downstream weir 32 in the substrate transport direction. The recovery groove 38 has a structure that is inclined toward the operation side or the drive side.

The recovery groove 38 receives the coating liquid that overflows from the liquid pool 34. The recovery groove 38 is connected to the circulation flow path 57 shown in FIG. 1. The coating liquid that flows into the recovery groove 38 is collected in the recovery tank 59 via the circulation flow path 57 and the circulation pump 58. The coating liquid collected in the recovery tank 59 is supplied to the bar block 20 via the supply flow path 52 and the liquid delivery pump 54. The recovery groove 38, the circulation flow path 57, the circulation pump 58, and the recovery tank 59 described in the embodiment are examples of components of the recovery section.

The shape of the bar block 20 is not limited to the shape shown in Figures 1 and 4. For example, the upstream weir 30 and downstream weir 32 shown in Figure 4 may have a shape with a slope at the tip. Also, the upstream weir 30 and downstream weir 32 may have a shape with a flat surface formed at the upper end.

Due to air entrained by the rotating bar coater 22 and instability of the meniscus of the coating liquid, the surface condition of the coating liquid supplied to the side of the bar coater 22 may become a problem. In such cases, by devising the shapes of the upstream weir 30 and downstream weir 32 and the shape of the bar receiving member 26, it is possible to adjust the flow of the coating liquid and optimize the surface condition of the coating liquid.

During the operation of the coating device 10, the bar coater 22 is rotated with coating liquid filling the space between the bar coater 22 and the bar support member 26. The coating liquid functions as a lubricant, suppressing wear of the bar coater 22 and the bar support member 26.

Considering the high speed rotation of the bar coater 22, a material with relatively low friction resistance is used for the bar receiving member 26. Examples of materials that can be used for the bar receiving member 26 include resin materials and materials obtained by impregnating metal materials with resin materials. The bar coater 22 and the bar receiving member 26 will be described in detail later.

[Example of bar coater structure]
The diameter of the bar coater 22 is set to be 5.0 mm or more and 15 mm or less. If the diameter of the bar coater 22 is less than 5.0 mm, the rigidity of the bar coater 22 is insufficient, vibration occurs during rotation, and there is a concern that the surface condition of the coating liquid will deteriorate due to the vibration.

If the diameter of the bar coater 22 exceeds 15 mm, the amount of coating liquid applied will be excessive, making it difficult to form a thin layer of the coating liquid on the substrate S. The diameter of the bar coater 22 is preferably 8.0 mm or more and 13 mm or less.

The mass of the bar coater 22 per meter is 0.5 kilograms or more and 3.0 kilograms or less. If the mass of the bar coater 22 per meter is less than 0.5 kilograms, the bar coater 22 is likely to vibrate when rotating. If the mass of the bar coater 22 per meter exceeds 3.0 kilograms, the bar coater 22 becomes heavy and difficult to replace.

Figure 5 is a perspective view of a wire bar coater. The wire bar coater 70 shown in the figure is produced by winding wire 74 around the side of a cylindrical core material 72 to form a wire row 76. The wire bar coater 70 can change the thickness of the wire 74 to change the volume of coating liquid held in the non-convex portion 75B between adjacent wires 74 in the substrate width direction. This makes it possible to apply coating liquid of the desired thickness with high precision. The bar coater 22 shown in Figure 1 etc. can be the wire bar coater 70 shown in Figure 5.

The wire bar coater 70 also has a structure in which the non-convex portion 75B is continuous. This allows the coating liquid held by the bar coater 22 to be continuous, and uniformity of the coating liquid transferred to the substrate S can be obtained. Note that the reference symbol 75A in FIG. 5 indicates the upper surface of the convex portion of the wire bar coater 70.

Figure 6 is a perspective view of a wireless bar coater. The wireless bar coater 80 shown in the figure has spiral grooves 84 formed on the side of a cylindrical core material 82. In the wireless bar coater 80, the pitch P of the grooves 84, the width W of the grooves 84, and the depth V of the grooves 84 are specified.

Since the wireless bar coater 80 has a continuous spiral groove 84, the coating liquid held in the wireless bar coater 80 is continuous, and uniformity of the coating liquid transferred to the substrate S can be obtained. When the coating liquid is held using an isolated cell such as a gravure roll, the components of the coating liquid can become clogged at the bottom of the cell, causing fluctuations in the amount of coating.

In other words, the wire bar coater 70 shown in Figure 5 and the wireless bar coater 80 shown in Figure 6 have a structure in which the coating liquid held on the side is continuous, thereby making it possible to avoid fluctuations in the amount of coating applied to the substrate S.

Figure 7 is an enlarged view of the side of the wireless bar coater. Reference numeral 80A in the figure represents a cross-sectional view of the wireless bar coater 80 in the substrate transport direction. Reference numeral 80B represents a partially enlarged view of a portion of the side of the wireless bar coater 80. The grooves 84 of the wireless bar coater 80 are formed with bottom surfaces 84A that are flat surfaces having a certain area. The non-groove portions 86 between adjacent grooves 84 of the wireless bar coater 80 are formed with top surfaces 86A that are flat surfaces having a certain area.

In the longitudinal direction of the wireless bar coater 80, the length of the upper surface 86A of the non-groove portion 86 is A, and the length of the bottom surface 84A of the groove 84 is B. The relationship between the length A of the upper surface 86A of the non-groove portion 86 and the length B of the bottom surface 84A of the groove 84 satisfies B/A≦1.

If the area of the bottom surface 84A of the groove 84 becomes smaller and the shape approaches a linear shape, unevenness in the thickness of the coating liquid may occur when the coating liquid is transferred from the bar coater 22 to the substrate S. Note that the groove 84 described in the embodiment is an example of a recess. The non-groove portion 86 described in the embodiment is an example of a non-recess.

The bar coater 22 shown in Figure 1 etc. can be either the wire bar coater 70 shown in Figure 5 or the wireless bar coater 80 shown in Figure 6. Comparing the wire bar coater 70 and the wireless bar coater 80, the wireless bar coater 80 is preferred because it is less prone to accumulation of dirt and is free of failures caused by wire breakage.

The wire 74 of the wire bar coater 70 and the groove 84 of the wireless bar coater 80 are planes perpendicular to the central axis 22A of the bar coater 22, and when they are inclined with respect to a plane parallel to the longitudinal direction of the bar coater 22, the surface condition of the coating liquid is improved. The angle at which the wire 74 and groove 84 are inclined can be appropriately determined according to the surface condition of the coating liquid.

The bar coater 22 is preferably made of a metal. From the viewpoint of corrosion resistance to the coating liquid, the bar coater 22 is preferably made of stainless steel. Examples of stainless steel that can be used for the bar coater 22 include SUS304 and SUS316. When the coating liquid is acidic, an acid-resistant material is used for the bar coater 22. SUS is an abbreviation for Steel Use Stainless.

The sides of the bar coater 22 are preferably subjected to a surface treatment such as hard chrome plating, diamond coating, or ceramic coating. This can improve abrasion resistance. The sides of the bar coater 22 are preferably subjected to a hydrophobic surface treatment. This reduces friction with the coating liquid as the bar coater 22 rotates.

The longitudinal ends of the bar coater 22 may be knurled to prevent slipping, coming off, and rotation. The effective coating length of the bar coater 22 in the longitudinal direction may be in the range of 100 mm to 1500 mm.

It is preferable that the coating liquid held on the side of the bar coater 22 be in a three-dimensional continuous state immediately before the coating liquid is transferred from the bar coater 22 to the substrate S. Immediately before the coating liquid is transferred from the bar coater 22 to the substrate S, the coating liquid held on the side of the bar coater 22 has a smaller variation in thickness in a cross section along the substrate transport direction than in a cross section along the substrate width direction.

This makes it possible to provide the coating device 10 with thin-film coating suitability at high speed and uniformly. An inkjet printing device in which pretreatment liquid is applied using such a coating device can prevent uneven ink concentration when ink droplets are ejected onto a printing medium and uneven ink adhesion such as localized peeling of ink.

[Example of configuration of bar receiving member]
<Water absorption rate and shore hardness>
A material having a water absorption rate of 0.05 percent or less is applied to the bar receiving member 26. If the water absorption rate of the bar receiving member 26 exceeds 0.05 percent, the bar receiving member 26 absorbs water and swells. This reduces the gap between the bar coater 22 and the bar receiving member 26 that is filled with the coating liquid, and wear of the side surface of the bar coater 22 due to contact between the bar coater 22 and the bar receiving member 26 may occur.

The bar receiving member 26 is made of a material having a Shore hardness of D60 or more. A bar receiving member 26 with a Shore hardness of less than D60 is prone to wear, and the gap between the bar coater 22 and the bar receiving member 26 becomes large. This causes the rotational freedom of the bar coater 22 to increase too much, making the bar coater 22 more likely to wobble during rotation, and the rotation of the bar coater 22 may become unstable. If the rotation of the bar coater 22 becomes unstable, the bar coater 22 and the bar receiving member 26 are more likely to come into contact, and the side of the bar coater 22 is more likely to wear.

Figure 8 is a table showing the results of the evaluation of the water absorption rate of the bar receiver and the wear evaluation of the bar coater with respect to the hardness of the bar receiver. The water absorption rate shown in Figure 8 was measured using the standard test method for water absorption of plastics specified in ASTM D570. The Shore hardness was measured using the standard test method for Rockwell hardness of plastics and electrical insulating materials specified in ASTM D785, using a durometer, type D. Note that D100< in the Shore hardness column indicates that the Shore hardness exceeds D100.

ASTM is an abbreviation of the American Society for Testing and Material. The conditions of the bar coater 22 applied to the evaluation test are as follows:

Material: SUS304
Diameter: 8 mm Rotation speed: 50 meters per minute Load: 200 Newtons Rotation period: 100 hours The rotation speed of the bar coater 22 was the tangential speed at the side of the bar coater 22 .

The bar receiving member 26 used in the evaluation test had a surface facing the bar coater 22 made using the materials shown in Figure 8 by applying one of the following:

The entire portion including the bar facing surface 26A is constructed using the material shown in Figure 8.

The bar facing surface 26A is coated using the material shown in Figure 8.

A sheet made of the material shown in Figure 8 is attached to the bar facing surface 26A.

The evaluation of wear and damage to the bar was performed by visually inspecting the surface of the bar coater 22 to confirm the presence or absence of wear and damage to the surface. Visual inspection here includes magnifying the side of the bar coater 22 using a microscope or the like.

In the abrasion and damage columns of the bars in Fig. 8, "+" indicates that abrasion and damage that may affect the amount of coating liquid applied are not visible. "-" in the same column indicates that abrasion and damage that may affect the amount of coating liquid applied are visible, and relatively small damage, etc. are visible. "--" in the same column indicates that abrasion and damage that may affect the amount of coating liquid applied are visible, and relatively large damage, etc. are visible.

The evaluation results shown in Figure 8 indicate that the material of the bar facing surface 26A of the bar receiving member 26 has a water absorption rate of 0.05 percent or less and a Shore hardness of D60 or more, which suppresses wear and scratches on the bar coater 22.

The lower limit of the water absorption rate may be 0. The upper limit of the Shore hardness may be the maximum Shore hardness of the material exceeding D100 shown in Figure 8.

<Surface free energy>
Fig. 9 is a table showing the results of the evaluation of the abrasion of the bar coater with respect to the surface free energy of the bar receiving portion. The various conditions in the evaluation test of the surface free energy are in accordance with the evaluation tests of the water absorption rate and Shore hardness. However, the rotation period of the bar coater 22 was set to 200 hours. The symbols in the bar abrasion and damage columns shown in Fig. 9 have the same meanings as those in the bar abrasion and damage columns shown in Fig. 8.

The bar receiving member 26 is made of a material whose surface free energy facing the bar coater 22 is 33 millinewtons per meter or less. If the surface free energy of the surface of the bar receiving member 26 facing the bar coater 22 exceeds 33 millinewtons per meter, the shear stress generated between the bar coater 22 and the bar receiving member 26 becomes relatively large. This makes the bar coater 22 and the bar receiving member 26 more susceptible to wear.

The surface free energy of the bar support member 26 on the surface facing the bar coater 22 is set to 33 millinewtons per meter or less, reducing the shear stress generated between the bar coater 22 and the bar support member 26 and suppressing wear of the bar coater 22 and the bar support member 26.

The surface of the bar receiving member 26 facing the bar coater 22 is preferably made of a material with a relatively low surface free energy. The lower limit of the surface free energy of the surface of the bar receiving member 26 facing the bar coater 22 can be set to 0. In practice, the lower limit of the surface free energy of the surface of the bar receiving member 26 facing the bar coater 22 is inherent to known low surface free energy materials.

If the side of the bar receiving member 26 is hydrophobic, the surfactant contained in the coating liquid can be adsorbed to the side of the bar receiving member 26, thereby improving the lubrication between the bar coater 22 and the bar receiving member 26.

<Corrosion resistance>
A material having corrosion resistance to the coating liquid is applied to the surface of the bar receiving member 26 facing the bar coater 22. When the coating liquid is acidic, a material having acid resistance to the coating liquid is applied to the surface of the bar receiving member 26 facing the bar coater 22.

[Coating solution]
〔viscosity〕
The viscosity of the coating liquid is preferably in the range of 0.5 mPascal-second to 5.0 mPascal-second. If the viscosity of the coating liquid is less than 0.5 mPascal, the fluidity of the coating liquid is too high, and the coating liquid may scatter. On the other hand, if the viscosity of the coating liquid is more than 5.0 mPascal-second, the fluidity of the coating liquid is too low, making leveling difficult and causing deterioration of the surface condition of the coating liquid.

〔surface tension〕
The surface tension of the coating liquid is preferably in the range of 30 to 45 millinewtons. If the surface tension of the coating liquid is less than 30 millinewtons, streaky coating unevenness may occur in the coating liquid applied to the substrate S. On the other hand, if the surface tension of the coating liquid exceeds 45 millinewtons, the wettability of the coating liquid to the substrate S may be insufficient.

[Specific examples of coating liquid]
The coating liquid may contain a component that aggregates the coloring material components of the aqueous ink used in the inkjet printing device. Examples of the component that aggregates the coloring material components of the aqueous ink include organic acids, inorganic acids, polyvalent metal ions, and cationic polymers.

The coating liquid contains a resin component from the viewpoint of ensuring adhesion to the substrate S. From the viewpoint of uniform dispersion in the coating liquid, the resin component is preferably dispersed in the coating liquid as latex particles. The average particle diameter of the latex contained in the coating liquid is preferably in the range of 30 nanometers or more and 500 nanometers or less.

If the average particle diameter of the latex is less than 30 nanometers, the coating liquid will form a continuous film that is too strong when formed into a film, making it difficult to clean if it becomes clogged in the groove 84 shown in Figure 6. On the other hand, if the average particle diameter of the latex exceeds 500 nanometers, the dispersibility of the latex in the coating liquid will be insufficient, and clogging due to soft aggregation of the latex may occur.

The solids concentration of the latex in the coating liquid is preferably in the range of 5.0 percent or more and 30 percent or less. If the solids concentration is less than 5.0 percent, the adhesion of the coating liquid to the substrate S may be insufficient. On the other hand, if the solids concentration exceeds 30 percent, the viscosity of the coating liquid may become too high, resulting in an increase in the amount of coating liquid applied to the substrate S.

A surfactant is added to the coating liquid. This improves the lubricity of the coating liquid and is also expected to reduce the shear force during rotation of the bar coater 22. The amount of surfactant added is preferably in the range of 0.1 to 0.2 mass percent. If the amount of surfactant added is less than 0.1 mass percent, it is difficult to obtain the above effect.

Figure 10 is a table showing the results of the evaluation of the wear of the bar coater with respect to the amount of surfactant added. The same conditions as those in the evaluation tests shown in Figures 7 and 8 were applied, and the wear of the bar coater 22 was evaluated for multiple coating solutions with different amounts of surfactant added.

The surfactant used was Olfin E1010 (product name, manufactured by Nissin Chemical Industry Co., Ltd.). The rotation period of the bar coater 22 was 100 hours. The material of the surface of the bar receiving member 26 facing the bar coater 22 was high-density polyethylene. The symbols in the bar wear column shown in Figure 10 have the same meanings as those in Figures 7 and 8.

Examples of preferred types of surfactants to be applied to acidic coating solutions include nonionic and anionic surfactants. Note that the types of surfactants are not limited to the above examples.

[Functions and Effects of the Coating Apparatus According to the Embodiment]
Fig. 11 is a table for explaining the difference in effect between the bar coating method and other coating methods. The figure shows the gravure method, the flexo method, and the bar method as examples. As the gravure method, direct gravure, offset gravure, and kiss reverse are shown as examples.

The figure shows the suitability of each coating method in terms of robustness of coating amount adjustment, suitability for switching substrate widths, and coating amount stability. Robustness of coating amount adjustment was evaluated in terms of suitability for switching metering rollers and variations in control parameters. The sign + indicates suitability, the sign - indicates suitability under certain conditions, and the sign -- indicates lack of suitability.

As shown in Figure 11, the bar coater method allows easy replacement of the bar coater and has a wide range of parameters for controlling the amount of coating. In addition, the bar coater method does not have the backup roller of the gravure method, making it easy to switch substrate widths. Furthermore, the bar coater method does not have a blade to scrape off the coating liquid, and wear on the bar coater 22 is reduced compared to methods that use a blade to scrape off the coating liquid.

Furthermore, according to the coating device of the embodiment, the following effects can be obtained.

[1]
A material having a water absorption rate of 0.05% or less and a Shore hardness of D60 or more is applied to the surface of the bar receiving member 26 facing the bar coater 22. This can prevent wear of the bar coater 22 caused by contact between the bar coater 22 and the bar receiving member 26.

[2]
A material having a surface free energy of 33 millinewtons per meter or less is applied to the surface of the bar receiving member 26 facing the bar coater 22. This reduces the shear stress generated between the bar coater 22 and the bar receiving member 26, and suppresses wear of the bar coater 22 and the bar receiving member 26.

[3]
The mass of the bar coater 22 is set to be equal to or greater than 0.5 kilograms and equal to or less than 3.0 kilograms per meter, which makes it possible to achieve both ease of replacement and suppression of vibration during rotation.

[4]
The bar coater 22 is a wire bar coater 70 having a core material 72 wound with a wire 74. This allows the coating liquid to flow along the non-convex portions 75B between adjacent wires 74, thereby preventing the non-convex portions 75B from becoming clogged with substances contained in the coating liquid.

[5]
A flat non-convex portion 75B is formed between adjacent wires 74, and the upper surface 75A of the wire 74 is flat. In a direction parallel to the central axis of the bar coater 22, when the length of the upper surface 75A is A and the length of the non-convex portion 75B is B, the relationship between the length A of the upper surface 75A and the length B of the non-convex portion 75B satisfies B/A≦1. This makes it possible to suppress unevenness in the coating liquid when the coating liquid is transferred from the wire bar coater 70 to the substrate S.

[6]
In the bar coater 22, a continuous spiral groove 84 is formed in the core material 82. This allows the coating liquid to flow along the groove 84, and clogging of the groove 84 with substances contained in the coating liquid is suppressed.

[7]
The groove 84 has a flat bottom surface 84A, and the non-groove portion 86 has a flat top surface 86A. In a direction parallel to the central axis of the bar coater 22, when the length of the top surface 86A is A and the length of the bottom surface 84A is B, the relationship between the length A of the top surface 86A and the length B of the bottom surface 84A satisfies B/A≦1. This makes it possible to suppress unevenness in the coating liquid when the coating liquid is transferred from the wireless bar coater 80 to the substrate S.

[8]
The conveying mechanism 60 that conveys the substrate S includes a first lift roller 62 and a second lift roller 64 that support the substrate S and press the substrate S against the bar coater 22. This makes it possible to adjust the tension applied to the substrate S and the wrap angle of the substrate S.

[9]
In the bar support portion 24, a slit 36 communicating with a supply flow path 52 is formed on a bottom surface 34A of a liquid pool 34 in which the bar coater 22 is immersed. A recovery groove 38 is formed on the outside of the upstream weir 30 and the downstream weir 32 which partition the liquid pool 34. As a result, of the coating liquid supplied from the slit 36 to the liquid pool 34, the excess flows out from the liquid pool 34 to the recovery groove 38. As a result, fresh coating liquid is supplied from the liquid pool 34 to the bar coater 22.

[10]
The parameter setting unit 118 sets parameters according to the coating conditions acquired using the coating condition acquisition unit 117. In this way, the parameters according to the coating conditions can be set.

[11]
The coating liquid contains a surfactant in an amount of 0.1 mass percent to 0.2 mass percent, both inclusive, which can improve the lubricity between the bar coater 22 and the bar receiving member 26.

[12]
The coating liquid contains latex, which makes it easier for a surfactant to be adsorbed around the latex dispersed in the coating liquid, thereby improving the lubricity between the bar coater 22 and the bar receiving member 26.

[Example of application to inkjet printing device]
12 is a diagram showing the overall configuration of an inkjet printing apparatus to which the coating device according to the embodiment is applied. The printing apparatus 500 includes a precoat unit 530 that applies a precoat liquid that aggregates coloring material components of the aqueous ink to a substrate 512. The coating device 10 according to the embodiment is applied to the precoat unit 530.

The printing device 500 is a roll-to-roll type inkjet printing device that prints an image in a single pass onto a substrate 512, which is a continuous medium. The substrate 512 may be a non-permeable medium such as a transparent film substrate used in flexible packaging. The substrate 512 described in the embodiment is an example of a printing medium.

The printing device 500 includes an unwinding section 520, a precoat section 530, a precoat drying section 532, a first suction drum 540, a second suction drum 542, a jetting section 550, an image sensor 560 and a winding section 570.

The transport path of the substrate 512 from the unwinding section 520 to the winding section 570 is called the substrate transport path. The substrate transport direction along the substrate transport path is called the substrate transport direction. The upstream side of the substrate transport path means the side closer to the unwinding section 520, and the downstream side means the side closer to the winding section 570.

Along the substrate transport path from the unwinding section 520, a precoat section 530, a precoat drying section 532, a first suction drum 540, a second suction drum 542, a jetting section 550, an image sensor 560 and a winding section 570 are arranged in this order.

The substrate conveying device 580, which conveys the substrate 512 unwound from the unwinding section 520 along the substrate conveying path to the winding section 570, is a roll-to-roll conveying mechanism including a first suction drum 540 and a second suction drum 542. The substrate conveying device 580 may be configured to include the unwinding section 520 and the winding section 570.

The unwinding section 520 is provided with an unwinding roll 522. The unwinding roll 522 is a roll on which the unprinted substrate 512 is wound in a roll shape. The unwinding section 520 is provided with an unwinding device that rotatably supports the core 524 of the unwinding roll 522.

The winding section 570 is provided with a winding roll 572. The winding roll 572 is a roll on which the printed substrate 512, which has been printed using the jetting section 550, is wound into a roll. The winding section 570 is equipped with a winding device. One end of the substrate 512 unwound from the unwinding section 520 is connected to the winding reel held by the winding device.

In the printing device 500, a precoat liquid is applied to the printing surface 512A of the substrate 512 in the precoat unit 530 before printing in the jetting unit 550. The precoat unit 530 is disposed at a position upstream of the jetting unit 550 on the substrate transport path.

The precoat liquid suppresses uneven density and uneven adhesion between the ink droplets and the substrate 512 when the ink droplets land on the substrate 512. The printing device 500 achieves high-speed inkjet printing using aqueous ink and precoat liquid, and even in high-speed printing, images with high density and resolution can be obtained, for example, with excellent reproducibility of fine lines and fine details.

The precoat unit 530 applies an aqueous primer as a precoat liquid. The aqueous primer contains a component that aggregates or insolubilizes the coloring material components in the water and aqueous ink. The aqueous primer may also include a component that thickens the water and ink.

The precoat drying section 532 performs a process of drying the aqueous primer applied to the printing surface 512A of the substrate 512 using the precoat section 530. The precoat drying section 532 is equipped with a hot air heater. An example of the hot air heater is one equipped with a slit nozzle that spans the entire width of the substrate 512.

From the standpoint of promoting leveling of the precoat liquid and ensuring adhesion of the precoat liquid, it is preferable that the surface tension of the substrate 512 be 30 millinewtons per meter or more and 60 millinewtons per meter or less.

Furthermore, when the surface tension of the substrate 512 _{is γs} and the surface tension of the precoat liquid is _γpc , the relationship between the surface tension of the substrate 512 _γs and the surface tension of the precoat liquid _γpc preferably satisfies _γs - _γpc ≧5 millinewtons per meter. This promotes leveling of the precoat liquid on the substrate 512, and ensures adhesion of the precoat liquid to the substrate 512.

The precoat drying unit 532 blows hot air toward the printing surface 512A of the substrate 512 to dry the water-based primer. An example of the configuration of the precoat drying unit 532 is one in which hot air is sprayed from a slit nozzle of a hot air heater.

The substrate 512 from which the precoat liquid has been dried is transported to the jetting section 550 via the first suction drum 540 and the second suction drum 542. The first suction drum 540 and the second suction drum 542 can be used as a non-contact transport section that blows air onto the substrate 512 to float the substrate 512 and transports the substrate 512, and changes the direction of the substrate 512 to bend the substrate 512 toward the substrate 512's printed surface 512A without contacting the substrate 512.

The jetting section 550 includes inkjet head 552K, inkjet head 552C, inkjet head 552M, inkjet head 552Y and inkjet head 552W.

Hereinafter, inkjet head 552K, inkjet head 552C, inkjet head 552M, inkjet head 552Y and inkjet head 552W may be collectively referred to as inkjet head 552.

Inkjet head 552 is a print head that ejects black, cyan, magenta, yellow, and white water-based inks. Water-based ink is ink in which coloring components such as dyes and pigments are dissolved or dispersed in water and a water-soluble solvent.

In this embodiment, an example is shown in which an aqueous pigment ink is used as the aqueous ink. An organic pigment is used as the pigment for each of the black, cyan, magenta, and yellow aqueous inks. Titanium oxide is used as the pigment for the aqueous white ink. The viscosity of each aqueous ink is 0.5 mPa-s or more and 5.0 mPa-s or less. The aqueous ink thickens by reacting with the aqueous primer.

Each inkjet head 552 is supplied with water-based ink from an ink tank of the corresponding color via a piping path. The ink tank and piping path are not shown in the figure.

The inkjet head 552 is a line type head capable of single pass printing, which performs a single scan and prints on the substrate 512 transported by the substrate transport device 580. A serial type head may be used as the inkjet head 552. A plurality of nozzles for ejecting ink are formed on the nozzle surface of the inkjet head 552. The plurality of nozzles may be arranged in a two-dimensional manner. A water-repellent film is formed on each nozzle surface of the inkjet head 552.

The inkjet head 552 can be constructed by connecting multiple head modules in the width direction of the substrate 512. The nozzle surface, nozzles, and water-repellent film are not shown. The width direction of the substrate 512 is a direction perpendicular to the substrate transport direction and parallel to the printing surface 512A of the substrate 512. Hereinafter, the width direction of the substrate 512 may be referred to as the substrate width direction.

Droplets of ink are ejected from the inkjet head 552 toward the printing surface 512A of the substrate 512, which is transported using the substrate transport device 580. The ejected ink droplets adhere to the substrate 512, and an image is printed on the printing surface 512A of the substrate 512. The ink applied to the printing surface 512A of the substrate 512 in the jetting section 550 undergoes a condensation and thickening reaction with the aqueous primer applied to the printing surface 512A of the substrate 512 in the precoat section 530.

In this embodiment, an example is shown of using four color inks, black, cyan, magenta and yellow, and white ink, but the ink colors and number of colors are not limited to this embodiment.

For example, a configuration using light-colored inks such as light magenta and light cyan, or a configuration using special-color inks such as green, orange, violet, clear ink, and metallic ink may be applied. Also, multiple inkjet heads 552 that eject ink of the same color may be arranged.

The order in which the inkjet heads 552 of each color are arranged is not particularly limited. However, since white ink is used when printing a white background image, it is preferable that the inkjet head 552W is arranged downstream of the inkjet head 552Y that ejects non-white ink. In an embodiment in which a non-transparent substrate 512 is used, the inkjet head 552W may not be provided.

The jetting unit 550 prints an ejection status monitoring pattern for each inkjet head 552 on the printing surface 512A of the substrate 512.

The image sensor 560 reads the ejection status monitoring pattern printed on the substrate 512. The printing device 500 analyzes the read data of the ejection status monitoring pattern to determine the ejection status of the inkjet head 552.

The image sensor 560 may be a CCD line sensor in which multiple photoelectric conversion elements are arranged in a row, or a CCD area sensor in which multiple photoelectric conversion elements are arranged in a two-dimensional manner.

The image sensor 560 may be configured to have a length corresponding to the full width of the image printed on the printing surface 512A of the substrate 512, or may be configured to scan along the substrate width direction to read the full width of the image printed on the printing surface 512A of the substrate 512.

Each step in inkjet printing is carried out, and the substrate 512 on which an image based on the print data has been printed is collected in the winding section 570. In this embodiment, the substrate 512 is transported by a roll-to-roll method, but various transport methods can be used to transport the substrate 512, such as a method of transporting the substrate 512 in sheets using a substrate transport device equipped with a transport belt, a transport drum, or the like.

[Example of Electrical Configuration of Inkjet Printing Apparatus]
The printing device 500 executes various programs using a processor to perform various controls and various processes. The various controls include transport control of the substrate 512, application control of the precoat liquid, drying control of the precoat liquid, ejection control of the inkjet head 552, and scanning control of the printed image. The various processes include color conversion processing, color separation processing, correction processing, a halftone function, drive voltage generation processing, and image processing of the scanned image.

The printing device 500 has a memory in which various data, various parameters, and various programs are stored. The processor executes the various programs by referring to the various data and various parameters.

[Specific examples of precoat liquid]
An example of the composition of the precoat applied to the printing apparatus 500 shown in FIG.

Malonic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 4.0 mass percent Triisopropanolamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 0.5 mass percent Acrylic resin particles A1: 8.0 mass percent as the amount of resin particles 1,2-propanediol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 10 mass percent Defoamer TSA-739 (product number) (manufactured by Momentive Performance Materials Japan, LLC, emulsion type silicone defoamer): 15.0 mass percent (0.01 mass percent as the solid content of the defoamer)
Water: balance totaling 100 mass percent. The precoat liquid was prepared as follows.

By using an aqueous dispersion of acrylic resin particles A1, the amount of acrylic resin particles A1 was 8% by mass as the amount of resin particles (C) in the precoat liquid. The aqueous dispersion of acrylic resin particles A1 was prepared as follows.

3.0 grams of a 62 mass percent aqueous solution of sodium dodecylbenzenesulfonate (Tokyo Chemical Industry Co., Ltd.) and 376 grams of water were added to a 1,000 milliliter three-neck flask equipped with a stirrer and a cooling tube, and heated to 90°C under a nitrogen atmosphere.

The following solutions A, B, and C were simultaneously added dropwise to the mixed solution in the heated three-neck flask over a period of three hours. After the addition was completed, the mixture was allowed to react for an additional three hours to obtain 500 grams of an aqueous dispersion of acrylic resin particles A1. The aqueous dispersion of acrylic resin particles A1 had a solid content, which is the amount of acrylic resin particles A1, of 10.1 mass percent.

Solution A is a solution in which 11.0 grams of a 50 weight percent aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate (manufactured by Aldrich) is dissolved in 20 grams of water.

Solution B is a mixture of 12.5 grams of 2-hydroxyethyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 5.0 grams of 2-(2-ethoxy)ethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 17.0 grams of benzyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 10.0 grams of styrene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

Solution C is a solution in which 6.0 grams of sodium persulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is dissolved in 40 grams of water. The glass transition temperature of the acrylic resin particles A1 is 26°C. The weight average molecular weight of the acrylic resin particles A1 is 69,000.

Note that the composition and preparation of the precoat liquid described above are merely examples, and the printing device shown in FIG. 12 may apply precoat liquid having other compositions and produced through other preparations. Examples of precoat liquids having other compositions are shown in FIG. 13 and FIG. 14.

Figure 13 is a table showing an example composition of a precoat liquid according to another specific example. The surfactant shown in Figure 13 may be Surfynol 465 (1 percent, product name, manufactured by Nissin Chemical Industry Co., Ltd.). The surfactant may be polyoxyethylene alkyl ethers such as Emulgen 1108 (product name, manufactured by Kao Corporation), Emulgen 1150S-60 (product name, manufactured by Kao Corporation), and Emulgen 1118S-70 (product name, manufactured by Kao Corporation).

Figure 14 is a table showing other composition examples of the precoat liquid according to other specific examples. The acrylic emulsion shown in Figure 14 may be Vinyblan 2687 (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), etc. The chlorinated polyolefin emulsion may be Superchlorine E-604 (chlorination degree 21%, trade name, manufactured by Nippon Paper Industries Co., Ltd.), etc. The surfactant may be Olfin E1010 (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), etc.

[Terminology]
The term "precoat liquid" is synonymous with terms such as pretreatment liquid and treatment liquid, and is a general term for liquid that is applied before printing. The precoat liquid is an example of a coating liquid.

The term printing device is synonymous with terms such as printing press, printer, printing device, image recording device, image forming device, image output device and drawing device. Image is to be interpreted broadly and includes color images, black and white images, single color images, gradation images and uniform density images.

The term printing includes concepts such as image recording, image forming, printing, drawing and printing. The term apparatus may include the concept of a system.

Image is used as a comprehensive term that includes not only photographic images but also designs, characters, symbols, line drawings, mosaic patterns, color-coded patterns, and various other patterns, as well as appropriate combinations of these. In addition, the term image may include the meaning of image signals and image data that represent an image.

The embodiments of the present invention described above may have their constituent elements modified, added to, or deleted as appropriate without departing from the spirit of the present invention. The present invention is not limited to the embodiments described above, and many modifications may be made by a person with ordinary knowledge in the relevant field within the technical concept of the present invention. Furthermore, the embodiments, modifications, and application examples may be implemented in appropriate combinations.

10 Coating device 12 Bar coating device 14 Conveying device 20 Bar block 22 Bar coater 22A Central shaft 24 Bar support portion 26 Bar receiving member 30 Upstream side weir 32 Downstream side weir 34 Liquid pool 34A Bottom surface 36 Slit 38 Recovery groove 40 Base 50 Coating liquid supply device 52 Supply flow path 54 Liquid feed pump 56 Coating liquid tank 57 Circulation flow path 58 Circulation pump 59 Recovery tank 60 Conveying mechanism 62 First lift roller 64 Second lift roller 66 Drive roller 68 Lifting device 70 Wire bar coater 72 Core material 74 Wire 75A Top surface 75B Non-convex portion 76 Wire row 80 Wireless bar coater 80A Cross-sectional view 80B Partially enlarged view 84 Groove 84A Bottom surface 86 Non-groove portion 86A Top surface 100 Processor 102 Memory 104 Parameter storage unit 110 Conveyance control unit 112 Lifting control unit 113 Bar drive control unit 114 Bar drive device 115 Pump control unit 116 Pump 117 Coating condition acquisition unit 118 Parameter setting unit 120 Display device 122 Display driver 130 Input device 140 Input/output interface 500 Printing device 512 Substrate 512A Printing surface 520 Unwinding unit 522 Unwinding roll 524 Core 530 Precoat unit 532 Precoat drying unit 540 First suction drum 542 Second suction drum 550 Jetting unit 552 Inkjet head 552C Inkjet head 552K Inkjet head 552M Inkjet head 552W Inkjet head 552Y Inkjet head 560 Image sensor 570 Winding unit 572 Winding roll 580 Substrate conveying device

Claims (14)

a bar member having a cylindrical shape and supported rotatably about a central axis, the bar member rotating about the central axis and contacting a substrate to apply a coating liquid containing water to the substrate;
a bar receiving member that rotatably supports the bar member, and in which a coating liquid to be supplied to the bar member is stored, the bar receiving member having a bar opposing portion that faces the bar member, the bar receiving member being made of a material having a water absorption rate of 0.05% or more and a Shore hardness of D60 or more ;
A conveying device that conveys the base material by supporting it, the conveying device including a moving mechanism that moves the position of the base material in a direction having a vertical component;
a lifting device that lifts and lowers the conveying device in a direction having a vertical component;
Equipped with
The lifting device is a coating device that brings the substrate into contact with the bar member at the start of a coating period in which the coating liquid is applied to the substrate, and moves the substrate away from the bar member at the end of the coating period . The coating device according to claim 1, wherein the bar facing portion is made of a material having a surface free energy of 33 millinewtons per meter or less. The coating device according to claim 1 or 2, wherein the bar member has a mass per meter of 0.5 kilograms or more and 3.0 kilograms or less. The coating device according to any one of claims 1 to 3, wherein the bar member has a spiral convex portion formed on the side surface. The coating device according to claim 4, wherein, in the direction parallel to the central axis, the length of the convex portion of the bar member is A, and the length of the non-convex portion between adjacent convex portions is B, the length A of the convex portion and the length B of the non-convex portion satisfy B/A≦1. The coating device according to any one of claims 1 to 5, wherein the side surface of the bar member is formed with a spiral recess. The coating device according to claim 6, wherein, in the direction parallel to the central axis, the length of the non-recessed portion of the bar member is A, and the length of the recessed portion is B, and the length A of the non-recessed portion and the length B of the recessed portion satisfy B/A≦1. a liquid storage section for storing the coating liquid to be applied to the bar member;
a recovery section that recovers the coating liquid overflowing from the liquid storage section;
The coating device according to claim 1 , further comprising: The liquid storage portion is provided at least one of an upstream position and a downstream position of the bar member in a substrate transport direction,
The coating apparatus according to claim 8 , wherein the recovery section is provided at a position corresponding to a position where the liquid storage section is provided. one or more processors;
one or more memories;
Equipped with
The processor,
Acquire coating conditions for coating the coating liquid on the substrate;
reading out parameters stored in the memory according to the coating conditions;
The coating apparatus according to claim 1 , further comprising: a coating unit configured to control coating of the coating liquid onto the substrate based on the read parameters. The coating device according to any one of claims 1 to 10, wherein the coating liquid contains 0.1 mass percent or more of a surfactant. The coating device according to any one of claims 1 to 11, wherein the coating liquid contains latex. The coating device according to claim 12, wherein the coating liquid contains latex having an average particle diameter of 30 nanometers or more and 500 nanometers or less. an application device that applies a coating liquid that aggregates ink onto a print medium;
an inkjet head that ejects ink onto a printing medium on which the coating liquid is to be applied;
Equipped with
The coating device includes:
a bar member having a cylindrical shape and supported rotatably about a central axis, the bar member rotating about the central axis and contacting the print medium to apply a coating liquid containing water to the print medium;
a bar receiving member that rotatably supports the bar member, and in which a coating liquid to be supplied to the bar member is stored, the bar receiving member having a bar opposing portion that faces the bar member, the bar receiving member being made of a material having a water absorption rate of 0.05% or more and a Shore hardness of D60 or more ;
a conveying device that conveys the print medium by supporting it, the conveying device including a movement mechanism that moves the position of the print medium in a direction having a vertical component;
a lifting device that lifts and lowers the conveying device in a direction having a vertical component;
Equipped with
The lifting device is an inkjet printing device that brings the substrate into contact with the bar member at the start of a coating period in which the coating liquid is applied to the substrate, and moves the substrate away from the bar member at the end of the coating period .

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