Drying conveying mechanism, printing device, and method for manufacturing printed matter

Abstract

To provide a drying conveyance mechanism which can be used stably for a long time, and which can manufacture a printed matter efficiently in a short time.SOLUTION: A drying conveyance mechanism is for conveying a recording medium when heating and drying and / or heating and curing ink coated on the recording medium. The drying conveyance mechanism includes: a platen incorporating a heater; a suction plate arranged on the platen, and for generating a suction pressure; a protective sheet which is arranged on the suction plate, and whose heat conductivity is equal to or greater than 0.3 W / mK; and a belt arranged on the protective sheet, and for conveying the recording medium.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a dry transport mechanism, a printing device, and a method for producing a printed matter. [Background technology]

[0002] When a thermally drying or thermosetting ink is applied to a recording medium, the ink must be dried or cured by heating or convection. In particular, in commercial printing and the like, where printing is performed continuously, it is common to dry or cure the ink while transporting the recording medium in a fixed direction.

[0003] A typical transport mechanism for transporting a recording medium is one equipped with an endless belt having a plurality of through holes. In such a transport mechanism, a porous suction plate and a suction unit (such as a blower) are arranged inside the endless belt, and the recording medium is transported while being in close contact with the endless belt (see, for example, Patent Document 1). If ink is dried or cured while the recording medium is in close contact with the endless belt, curling, cockling, and the like are less likely to occur on the recording medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-90344 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, stainless steel is widely used for the endless belt because it is not easily affected by heat from the heat irradiating section, has good flatness, etc. On the other hand, the suction plate is generally made of a resin, aluminum, etc., but depending on the type of suction plate, it may be scraped or its holes may be crushed when the endless belt is rotated, making it impossible to maintain sufficient suction force for a long period of time.

[0006] Furthermore, in recent years, there has been a demand for more efficient production of printed materials in a shorter time. To address this issue, it has been considered to increase the transport speed of the recording medium when the ink dries (or hardens), but increasing the transport speed shortens the heating time for the recording medium, making it difficult to sufficiently increase the temperature of the recording medium and ink. Patent Document 1, mentioned above, describes a method of heating the endless belt by arranging a heater inside a roller that rotates the endless belt. However, with this method, the temperature of the endless belt tends to drop while the endless belt is rotating, making it difficult to sufficiently heat the recording medium and ink.

[0007] One embodiment of the present invention aims to provide a drying and conveying mechanism that can be used stably over a long period of time and can produce printed matter efficiently in a short period of time, and to provide a method for producing printed matter using the same. [Means for solving the problem]

[0008] One embodiment of the present invention provides a drying and conveying mechanism for conveying a recording medium when heating and drying and / or heating and curing ink applied to the recording medium, the drying and conveying mechanism having a platen with a built-in heater, an adsorption plate placed on the platen for generating adsorption pressure, a protective sheet placed on the adsorption plate and having a thermal conductivity of 0.3 W / mK or more, and a belt placed on the protective sheet for conveying the recording medium.

[0009] One embodiment of the present invention provides a printing device including an ink application unit for applying ink to a recording medium and the above-described drying and transport mechanism.

[0010] One embodiment of the present invention also provides a method for producing a printed matter, which includes the steps of preparing a recording medium coated with ink, and drying and / or curing the ink while transporting the recording medium in a predetermined direction using the drying and transport mechanism, wherein in the step of drying and / or curing the ink, the back surface of the recording medium is adsorbed to the belt and the recording medium is heated by the heater. [Effects of the Invention]

[0011] The drying and conveying mechanism of the present invention can be used stably for a long period of time, and the drying and conveying mechanism can dry or cure ink efficiently in a short period of time to produce printed matter. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a printing device including a drying and conveying mechanism according to one embodiment of the present invention. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of a drying and conveying mechanism according to an embodiment of the present invention. [Figure 3] FIG. 3 is a plan view of a platen included in the drying and conveying mechanism according to one embodiment of the present invention. [Figure 4] FIG. 4 is a graph comparing the ink temperature and ink drying time of Example 4 and Comparative Example 1. [Figure 5] FIG. 5 is a graph showing the relationship between the thermal conductivity of the protection sheet of the drying transport mechanism and the drying time of the ink. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0014] 1. Drying and conveying mechanism The dry transport mechanism according to one embodiment of the present invention is used to dry heat-curable or heat-dryable ink. An example (side view) of a printing apparatus that can use the dry transport mechanism 210 is shown in FIG.

[0015] The printing apparatus 1 shown in FIG. 1 includes an ink application unit 100 for applying ink 11 onto a recording medium 10 and a drying unit 200 for heat-drying and / or heat-curing (hereinafter, collectively referred to as "drying") the ink on the recording medium 10. The drying and conveying mechanism 210 of this embodiment can be disposed in the drying unit 200 and is a mechanism for conveying the recording medium 10 while drying the ink using a heat irradiation unit 220 or a convection unit 230 in the drying unit 200. In the drying unit 200, the belt 214 of the drying and conveying mechanism 210 moves in a predetermined direction while holding the recording medium 10, allowing the recording medium 10 to pass under the heat irradiation unit 220 or the convection unit 230. Therefore, the ink on the recording medium 10 can be dried by the heat from the heat irradiation unit 220 and the convection caused by the convection unit 230. A partially enlarged cross-sectional view of the drying and conveying mechanism 210 is shown in FIG. 2. FIG. 2 is an enlarged cross-sectional view of the area of ​​the drying and conveying mechanism 210 that is used to convey the recording medium 10, that is, the area facing the heat irradiation means 220 and the convection means 230 (the area surrounded by the dotted line in FIG. 1).

[0016] 2, the drying conveyance mechanism 210 of this embodiment includes a platen 211 incorporating a heater 211b, an adsorption plate 212 arranged on the platen 211, a protective sheet 213 arranged on the adsorption plate 212, and a belt 214 arranged on the protective sheet. This embodiment also includes a suction unit 215 that draws gas from the platen 211 side and generates a suction pressure for adsorbing the recording medium to the surface of the belt 214. The thermal conductivity of the protective sheet 213 is 0.3 mW / N or higher. In this specification, the thermal conductivity is a value measured by a steady-state comparative method.

[0017] As described above, in conventional conveyance mechanisms, the suction plate and the endless belt are in direct contact with each other, and the movement of the endless belt causes wear on the suction plate, making it difficult to generate a stable suction pressure on the recording medium over a long period of time. In contrast, in the dry conveyance mechanism 210 of this embodiment, a protective sheet 213 is disposed between the suction plate 212 and the belt 214. This makes it possible to suppress wear on the suction plate 212 caused by the movement of the belt 214. Therefore, the suction force is less likely to change over a long period of time, making it possible to stably convey the recording medium 10.

[0018] Furthermore, in conventional printing devices including a transport mechanism, heat is applied to the recording medium only from the heat irradiation means or convection means, making it difficult to efficiently dry the ink as the recording medium transport speed increases. In contrast, the drying transport mechanism 210 of this embodiment is provided with a platen 211 incorporating a heater 211b. This allows the recording medium 10 to be heated from its backside as well. This makes it possible to very efficiently dry the ink on the recording medium 10. Furthermore, in the transport and drying mechanism 210 of this embodiment, a protective sheet 213 and the like are provided between the platen 211 incorporating the heater 211b and the belt 214. However, because the thermal conductivity of the protective sheet 213 is sufficiently high, heat from the heater 211b can be efficiently transferred to the belt 214 and the recording medium 10.

[0019] The drying and conveying mechanism 210 of this embodiment may have a configuration other than that described above, and may have, for example, a driving means (not shown) for rotating the belt 214 at a desired speed, a control unit (not shown) for adjusting the output of the heater 211b, etc. Each configuration of the drying and conveying mechanism of this embodiment will be described below.

[0020] (Platen) The platen 211 of the dry conveying mechanism 210 of this embodiment is a member that supports the suction plate 212 and heats the suction plate 212, the protective sheet 213, and the belt 214, and ultimately the recording medium 10. In this embodiment, the platen 211 is disposed in an area used for transporting the recording medium 10 within the dry conveying mechanism 210, that is, along a flat surface on the top of the dry conveying mechanism 210. In this embodiment, the platen 211 is disposed over the entire area used for transporting the recording medium 10 within the dry conveying mechanism 210.

[0021] 2, the platen 211 has a housing 211a and heaters 211b arranged inside the housing 211a. The housing 211a of the platen 211 in this embodiment has an outer shape that is approximately rectangular parallelepiped, and has holes on its side into which the multiple heaters 211b can be inserted.

[0022] A plan view of the housing 211a is shown in Fig. 3. As shown in Fig. 2 and Fig. 3, the housing 211a of the platen 211 has, on its top surface, a mesh-like gap 211c and pillar-like portions 211d arranged in the gap 211c.

[0023] The gap 211c is a flow path for gas when gas is sucked from the suction plate 212 side, which will be described later, and a through-hole 211e communicating with the gap 211c is arranged near the center of the housing 211a. The through-hole 211e is connected to a suction unit 215 on the rear surface of the platen 211. When the suction unit 215, which will be described later, is driven, the air on the suction plate 212 side is exhausted to the outside via the through-hole 211e and the gap 211c, and a suction pressure for adsorbing the recording medium 10 to the surface of the belt 214 is generated.

[0024] On the other hand, the columnar portions 211d support the attraction plate 212 and transfer heat from the heater 211b to the attraction plate 212. There are no particular limitations on the shape of each columnar portion 211d, but in this embodiment, the columnar portion 211d has a rectangular shape with sides of approximately 5 mm to 15 mm in a plan view and a height of approximately 1 mm. However, the shape is not limited to this, and the columnar portions 211d may have a cylindrical shape or the like. There are also no particular limitations on the width between adjacent columnar portions 211d, but in this embodiment, it is approximately 10 to 20 mm.

[0025] Here, it is preferable that the housing 211a of the platen 211 is made of a material that is resistant to deformation or thermal expansion due to the heat from the heater 211b. Therefore, the material of the housing 211a is preferably metal, and in particular, from the viewpoint of workability, aluminum, alumina ceramics, fluororesin (polytetrafluoroethylene, etc.), stainless steel, etc. are preferable.

[0026] Furthermore, the thickness of the housing 211a is not particularly limited, and can usually be set to about 15 mm to 30 mm.

[0027] On the other hand, the shape of the heater 211b built into the platen 211 is not particularly limited, but it is preferable that it be able to heat the recording medium 10 uniformly in the width direction. In this embodiment, the cylindrical heater 211b is arranged inside the platen 211 so that its axial direction is approximately perpendicular to the transport direction of the recording medium. Note that while only one heater 211b may be arranged inside the platen 211, it is preferable that a plurality of heaters 211b are arranged along the transport direction of the recording medium 10 from the viewpoint of efficiently drying the ink on the recording medium 10. When a plurality of heaters 211b are arranged, the temperature and output may be adjusted for each heater 211b.

[0028] The type of heater 211b is not particularly limited, but from the viewpoint of energy density, an internal heater is preferable, and a sheath heater or a cartridge heater is particularly preferable.

[0029] (Adsorption plate) The suction plate 212 is a member for ensuring suction pressure when suctioning the recording medium to the belt 214 side. In this embodiment, the suction plate 212 is arranged in the area used for transporting the recording medium 10 in the dry transport mechanism 210, that is, along the flat surface on the top of the dry transport mechanism 210. Also, in this embodiment, the suction plate 212 is arranged over the entire area used for transporting the recording medium 10 in the dry transport mechanism 210.

[0030] The shape of the suction plate 212 is not particularly limited as long as it can ensure sufficient suction pressure, and it can be a plate-like member having multiple holes. The shape of the holes in the suction plate 212 is not particularly limited as long as at least a portion of the holes connects the surface on the protective sheet 213 side to the surface on the platen 214 side. However, from the viewpoint of ensuring sufficient suction pressure, the suction plate 212 is preferably porous. The shapes and opening diameters of the multiple holes in the porous shape may be the same or different. The average diameter of the pores in the suction plate 212 is preferably 10 μm to 100 μm, and more preferably 50 μm to 100 μm. The average diameter is the average value measured by measuring the opening diameters of multiple holes using an optical microscope. The porosity of the suction plate 212 is preferably 20% to 30%. The porosity is determined as follows: First, the surface of the suction plate 212 is observed using an optical microscope, and the total area of ​​the pores present per unit area is calculated. The porosity is calculated by dividing the total area of ​​the holes by the unit area ((total area of ​​the holes / unit area) × 100). When the diameter of the holes in the suction plate 212 is within the above range and the porosity is within the above range, it becomes easier to ensure sufficient suction pressure.

[0031] Furthermore, it is preferable that the attraction plate 212 easily transfers heat from the heater 211b of the platen 211 to the belt 214. Specifically, the thermal conductivity measured by a steady-state comparative method is preferably 5 W / mK or more, and more preferably 10 W / mK or more. When the thermal conductivity of the attraction plate 212 is 5 W / mK or more, it becomes possible to efficiently transfer heat from the heater 211b built into the platen 211 to the belt 214.

[0032] The thickness of the adsorption plate 212 is appropriately selected depending on the type of the adsorption plate 212 and the like.

[0033] The material constituting the adsorption plate 212 may be any material that can form the desired holes, has sufficient strength, and has high heat resistance and thermal conductivity. Examples include metals, with aluminum, alumina ceramics, and fluororesins (such as polytetrafluoroethylene) being particularly preferred. These materials are easy to process into the above-mentioned porous shape.

[0034] The suction plate 212 may be a commercially available product, examples of which include TTS MC240AL and TTS HD210AL.

[0035] (protective sheet) It is sufficient that the protective sheet 213 covers at least the suction plate 212 and is capable of suppressing contact between the suction plate 212 and the belt 214. In this embodiment, similar to the suction plate 212, the protective sheet 213 is arranged in an area used for transporting the recording medium 10 within the drying transport mechanism 210, that is, along the flat surface on the top of the drying transport mechanism 210. However, the protective sheet 213 may be arranged not only between the suction plate 212 and the belt 214, but also between other members (not shown) and the belt 214 in order to protect the other members.

[0036] As described above, the thermal conductivity of the protective sheet 213 may be 0.3 mW / mK or more, but is preferably 1.0 mW / mK or more. If the thermal conductivity of the protective sheet 213 is 0.3 mW / mK or more, the protective sheet 213 will be able to transfer heat from the heater 211b to the belt 214 side much more easily, improving the drying properties of the ink on the recording medium 10. There is no particular upper limit to the thermal conductivity of the protective sheet 213, but when a sheet containing glass fiber (also referred to as "glass cloth" in this specification) is used as the protective sheet 213, for example, the upper limit is about 8 mW / mK. The thermal conductivity of the protective sheet 213 is a value measured by the steady-state comparative method as described above. When measuring the thermal conductivity of the protective sheet 213, T LThe protective sheet 213 is fixed by suction at a suction pressure of 3 kPa onto a porous chuck heated to ° C. Then, the temperature T u Then, calculate using the following formula: Thermal conductivity ∝d·Q / (TL-Tu) In the above formula, d is the thickness of the protective sheet 213, and Q is the heat flux.

[0037] Furthermore, it is preferable that protective sheet 213 not only has the above-mentioned thermal conductivity but also has a strength (yield stress) that prevents plastic deformation due to the frictional force caused by the sliding of belt 214. Specifically, the yield stress is preferably 20 MPa or more, and more preferably 50 MPa or more. If protective sheet 213 has a yield stress of 15 MPa or more, protective sheet 213 will not plastically deform even when belt 214 slides at high speed, and can stably protect suction plate 212. The above strength is a value measured in accordance with JIS B7721 tensile test. More specifically, it is measured by pulling a JIS B7721 test piece (dumbbell-shaped with a test width of 10 mm and a length of 115 mm) at a rate of 5 mm / min.

[0038] On the other hand, the coefficient of friction between protective sheet 213 and belt 214 is preferably 0.5 or less, and more preferably 0.3 or less. The coefficient of friction between protective sheet 213 and belt 214 can be determined as follows. First, protective sheet 213 is placed on belt 214, and a weight M [kg] with protective sheet 213 fixed to its bottom surface is further placed on belt 214. Then, protective sheet 213 is moved relative to belt 214, and the force f [N] at this time is measured with a push-pull gauge. Then, the coefficient of friction is calculated using the following formula. Friction coefficient = f / 9.8M If the coefficient of friction is 0.5 or less, friction is unlikely to occur when belt 214 rotates, and not only can wear on protection sheet 213 be suppressed, but the power required to rotate belt 214 can also be reduced.

[0039] Furthermore, when the recording medium is heated, the temperature of the protective sheet 213 increases, so the protective sheet 213 preferably has sufficient heat resistance and a glass transition temperature of 200° C. or higher.

[0040] Furthermore, it is preferable that the protective sheet 213 has sufficient breathability so as not to impede suction from the belt 214 side to the adsorption plate 212 side. For example, if the protective sheet 213 has a large number of holes, sufficient breathability can be ensured. Specifically, the flow path resistance is 1.0×10 -4 kg / m 4 It is preferable that the opening ratio is 10 to 50%, and more preferably 20 to 25%. When the opening ratio is 10 to 50%, a sufficient suction pressure can be generated on the recording medium. The opening ratio of the protective sheet 213 is calculated as follows: The protective sheet 213 is observed with an optical microscope, and the total area of ​​the holes present per unit area is calculated. Then, the total area of ​​the holes is divided by the unit area ((total area of ​​the holes / unit area) × 100) to obtain the opening ratio.

[0041] Here, protective sheet 213 may consist of a single layer, or may be a laminate of two or more layers. Furthermore, the material of protective sheet 213 is not particularly limited as long as it has the above-mentioned thermal conductivity, breaking strength, coefficient of friction with belt 214, heat resistance, aperture ratio, etc. Examples of materials for protective sheet 213 include glass cloth containing glass fiber, polyimide sheet, PEEK (polyether ether ketone) sheet, carbon sheet, resin belt, etc. The glass cloth may be glass fiber impregnated with polytetrafluoroethylene, silicone rubber, molybdenum disulfide, carbon, etc. Furthermore, for example, an adhesive layer or the like may be disposed on one surface of the protective sheet.

[0042] The glass cloth may be a commercially available product, and examples thereof include VALFLON (registered trademark) 7991 (PTFE-impregnated glass cloth, manufactured by Valqua Corporation), TC-BG (silicone rubber-impregnated glass cloth, manufactured by Shin-Etsu Chemical Co., Ltd.), TC-EG (silicone rubber-impregnated glass cloth, manufactured by Shin-Etsu Chemical Co., Ltd.), TC-TAP-2 (silicone rubber-impregnated glass cloth, manufactured by Shin-Etsu Chemical Co., Ltd.), and TC-TA-1 (silicone rubber-impregnated glass cloth, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0043] The thickness of the protective sheet 213 is appropriately selected depending on the thermal conductivity of the protective sheet 213, and is preferably 100 μm or more and 500 μm or less, and more preferably 200 μm or more and 400 μm or less. If the thickness of the protective sheet 213 is 100 μm or more, it is possible to protect the suction plate 212 for a long period of time. On the other hand, if the thickness of the protective sheet 213 is 500 μm or less, heat from the heater 211b of the platen 211 is easily conducted to the recording medium.

[0044] (belt) The belt 214 is a member for transporting the recording medium 10, and its shape is not particularly limited as long as it can transport the recording medium 10 in a fixed direction at a desired speed. In this embodiment, the belt 214 is an endless belt, and is disposed outside the platen 211, the suction plate 212, and the protective sheet 213, so as to surround them. However, the structure of the belt 214 is not limited to this structure, and it may be connected to, for example, the transport means 130 of the ink application unit of the printing apparatus 1. It may also be configured to pass only on the upper side of the drying transport mechanism 210. The belt 214 is controlled by a driving means (not shown) to move (rotate in this embodiment) in a predetermined direction at a predetermined speed. The driving means may be similar to the driving means of a known transport mechanism and may include, for example, a roller (not shown). The roller may be equipped with a heating device.

[0045] In this embodiment, the belt 214 is formed with a plurality of through-holes penetrating the belt 214 in the thickness direction. The shape of the through-holes is not particularly limited; in this embodiment, the through-holes are cylindrical. The size of the through-holes is appropriately selected depending on the material of the belt 214, etc. However, from the viewpoint of uniformly transferring heat from the heater 211b to the recording medium 10 and, at the same time, closely adhering the recording medium 10 to the belt 214 by suction with the suction unit 215, through-holes with an opening diameter of 0.2 mm to 1 mm are preferred, and through-holes with an opening diameter of 0.4 mm to 0.6 mm are more preferred. Through-holes with an opening diameter of 0.2 mm or more are easy to form. On the other hand, if the opening diameter is 1 mm or less, marks (suction marks) of the through-holes are less likely to remain on the recording medium 10 when the recording medium 10 is suctioned. Note that, in this specification, the opening diameter of the through-holes in the belt 214 refers to the maximum diameter of the through-holes on the front and back surfaces of the belt 214. The shapes of the multiple through holes in belt 214 may be the same or different, and the opening diameters may be constant or different. Furthermore, the through holes may be arranged at regular intervals or randomly. However, it is preferable that the through holes be arranged approximately evenly on belt 214.

[0046] Furthermore, the aperture ratio of the belt 214, i.e., the ratio of the total aperture area of ​​the through holes present per unit area of ​​the belt 214 ((total aperture area / unit area) × 100), is preferably 2% or more and 20% or less, and more preferably 5% or more and 10% or less. If the aperture ratio of the belt 214 is 2% or more, a sufficient adsorption force can be generated, making it easier to bring the recording medium into close contact with the belt 214. On the other hand, if the aperture ratio is 20% or less, the contact area between the belt 214 and the recording medium 10 becomes relatively large, making it easier to transfer heat from the platen 211 (heater 211b) side to the recording medium 10.

[0047] Furthermore, the belt 214 is heated from both sides, by the heat irradiation means 220 of the printing device 1 and the heater 211b of the platen 211. Therefore, it is preferable that the belt has a low coefficient of thermal expansion. Furthermore, from the viewpoint of uniformly transferring heat from the heater 211b side of the platen 211 to the recording medium, it is preferable that the belt is made of a material with high thermal conductivity. Therefore, the material of the belt 214 is preferably metal, and stainless steel (also referred to as "SUS" in this specification) is preferable. Furthermore, from the viewpoint of low thermal expansion, it is particularly preferable that the material has a coefficient of thermal expansion of 10.6×10 -6 It is preferable to use a precipitation hardening stainless steel having a hardness of 1 / °C or less.

[0048] The thickness of the belt 214 is appropriately selected depending on the material, desired strength, etc., but is preferably 0.1 mm to 0.5 mm, and more preferably 0.15 mm to 0.35 mm. If the thickness of the belt 214 is 0.15 mm or more, sufficient strength is likely to be obtained. On the other hand, if the thickness of the belt 214 is 0.35 mm or less, the belt 214 can be easily rotated.

[0049] (suction part) The suction unit 215 is a member connected to the through-hole 211e of the platen 211 described above, and serves to suck gas from the belt 214 and the adsorption plate 212. The suction unit 215 is required to be a blower that can withstand a heat-resistant temperature (above the belt temperature) in order to suck in hot air.

[0050] (others) The drying conveying mechanism 210 of this embodiment may further include necessary components in addition to the platen 211, suction plate 212, protective sheet 213, belt 214, and suction unit 215 described above. As described above, the drying conveying mechanism 210 may further include a driving unit for driving the belt 214, a control unit for controlling the rotation speed of the belt 214 and the temperature of the heater 211b in the platen 211, and the like. Note that in the drying conveying mechanism 210, a heating device may be provided on a roller or the like for driving the belt 214, and the recording medium 10 may be heated by the heating device and the heater 211b of the platen 211 described above. The drying conveying mechanism 210 may also include a temperature sensor or the like for monitoring the temperature of the surface of the belt 214. Furthermore, the drying conveying mechanism 210 may include an adjustment mechanism for adjusting the tension of the belt 214, a displacement meter for detecting deformation of the belt 214, and the like.

[0051] 2. Printing device and method for producing printed matter The above-described drying and transporting mechanism 210 may be combined with an ink application unit for applying ink onto a recording medium to form a printing apparatus. Furthermore, the above-described drying and transporting mechanism 210, the ink application unit, and a drying unit (e.g., a heat irradiation unit or a convection unit) that is arranged opposite the ink drying and transporting mechanism 210 across the recording medium and dries the recording medium from the surface side may be combined to form a printing apparatus. Below, a method for producing a printed matter using a printing apparatus 1 having the drying and transporting mechanism 210, the ink application unit 100, and the drying unit 200 shown in FIG. 1 will be described.

[0052] In a method for producing a printed matter using the printing device 1, first, a recording medium 10 is prepared on which ink 11 is applied by the ink application unit 100. Specifically, a recording medium supply mechanism 110 supplies the recording medium 10 to a conveyance means 130. Then, while the recording medium 10 is being conveyed by the conveyance means 130, ink is ejected from an ink ejection unit 120 by an inkjet method or the like to form a desired pattern on the recording medium 10.

[0053] Next, the ink on the recording medium 10 is dried in the drying unit 200. Specifically, the recording medium 10 coated with ink is moved onto the drying conveyance mechanism 210 of the drying unit 200. At this time, the recording medium 10 is positioned so that the ink-coated surface (the surface of the recording medium) faces the drying means (in this embodiment, the heat irradiation means 220 and the convection means 230). Then, while the drying conveyance mechanism 210 adheres the recording medium 10 to the belt 214, the recording medium 10 passes below the heat irradiation means 220 and below the convection means 230 to dry the ink. The heat irradiation means 220 irradiates, for example, infrared light. Furthermore, the convection means 230 blows air at an ambient temperature or higher and up to 160°C toward the recording medium 10 at a speed of 5 to 20 m / s. At this time, the recording medium 10 is also heated by the heater 211b in the drying conveyance mechanism 210 to efficiently dry the ink.

[0054] Here, the recording medium 10 may be adsorbed immediately after being placed on the drying conveyance mechanism 210, but deformation of the recording medium is likely to occur after drying by the drying means (in this embodiment, heat irradiation by the heat irradiation means 220 and wind blowing by the convection means 230) has begun. Therefore, in this embodiment, it is preferable to adsorb the recording medium 10 0.4 seconds or more after the start of drying (start of heat irradiation by the heat irradiation means 220). The timing of adsorption can be adjusted, for example, by the relative positions of the heat irradiation means 220 and the drying conveyance mechanism 210, the arrangement area of ​​the adsorption plate 212 within the drying conveyance mechanism 210, etc.

[0055] Here, the pressure when the recording medium 10 is adsorbed by the drying and conveying mechanism 210 (also referred to herein as "adsorption pressure") is preferably 3 to 20 kPa, more preferably 5 to 10 kPa, from the viewpoint of suppressing deformation of the recording medium. In addition, the conveying speed of the recording medium 10 is usually preferably 1600 m / s or less, but the faster the speed, the higher the productivity of printed matter, which is preferable.

[0056] Furthermore, when the drying and conveying mechanism 210 conveys the recording medium 10, the temperature of the belt 214 is preferably 160°C or less, and more preferably 100°C to 150°C. This temperature varies depending on the type of recording medium 10, but if the recording medium 10 is paper, for example, setting the temperature to 160°C or less can prevent scorching. The belt surface temperature is preferably 160°C or less to speed up drying. If it is any higher, paper scorching will occur.

[0057] The ink that can be used in this printing method is any ink that can be dried or cured by heat, and known water-based inks and thermosetting inks can be used.

[0058] Furthermore, there are no particular limitations on the type of recording medium that can be applied to this printing method, and it is possible to use plain paper ranging from thin paper to thick paper, medium-quality paper, high-quality paper, recycled paper, coated printing paper such as art paper or coated paper, commercially available Japanese paper or postcard paper, cloth, etc.

[0059] (others) In the above, it has been described that the ink is applied from the ink ejection unit 120 by the inkjet method in the ink application unit 100, but the ink application method is not limited to this method. For example, the ink application unit 100 may apply ink onto the recording medium by a dispenser method, gravure printing method, screen printing method, etc.

[0060] In the above description, the drying unit 200 includes the heat irradiation unit 220 and the convection unit 230, but only one of these may be provided. Furthermore, as long as the ink can be dried by heating, the drying unit is not particularly limited to these units. Furthermore, as described above, the printing apparatus does not necessarily have to include the drying unit 200; for example, the ink may be dried by heating only using the heating and drying mechanism 210. [Example]

[0061] Specific examples of the present invention will be described below together with comparative examples, but the present invention is not limited to these.

[0062] [Examples 1 to 4 and Comparative Examples 1 to 3] A drying and conveying mechanism shown in Fig. 2 was prepared. Specifically, a drying and conveying mechanism 210 was prepared, which included a 27 mm thick platen 211 incorporating an internal heater 211b, a 9 mm thick suction plate 212 (MC240AL, manufactured by TTS), a 0.45 mm thick protective sheet 213 (described below), and an endless belt 214 (gap to paper: 10 µm) made of stainless steel and 0.05 mm thick. However, the drying and conveying mechanism of Comparative Example 1 was a drying and conveying mechanism having only the endless belt 214.

[0063] In the examples and comparative examples, the following protective sheets were used. Comparative Example 2: Product name: Marinetex 0.7A, manufactured by Nichias Corporation, thermal conductivity 0.05 W / mK Comparative Example 3: Product name: Insultex, manufactured by Nichias Corporation, thermal conductivity: 0.1 W / mK Example 1: Product name TC-TAP-2, manufactured by Shin-Etsu Chemical Co., Ltd., thermal conductivity 0.7 W / mK Example 2: Product name TC-TA-1, manufactured by Shin-Etsu Chemical Co., Ltd., thermal conductivity 1.0 W / mK Example 3: Product name: TC-EG, manufactured by Shin-Etsu Chemical Co., Ltd., thermal conductivity: 3.5 W / mK Example 4: Product name: TC-BG, manufactured by Shin-Etsu Chemical Co., Ltd., thermal conductivity: 7.3 W / mK The thermal conductivity of the protective sheet was measured by a steady-state comparative method.

[0064] On the other hand, OK top coat (rice weight 128 g / m) was used as a recording medium. 2 An inkjet printer (Konica Minolta KM1024i head) was filled with Konica Minolta's water-based inkjet ink, and a 7.5 cm x 7.5 cm pattern was applied.

[0065] The ink-coated recording medium was then placed on the belt of the drying and conveying mechanism of the example and comparative example, and the recording medium was moved at a predetermined speed (1.6 m / s). During this process, the belt was heated to 150°C by a heating device attached to a roller in the belt conveying means. In these examples, the belt near the heating device is also referred to as the "upstreammost portion of the belt." Heating was not performed from the surface side of the recording medium. Furthermore, in comparative examples 2 and 3 and examples 1 to 4, heating was performed not only by the heating device of the roller, but also by a heater built into the platen of the drying and conveying mechanism 210.

[0066] The ink temperature was measured with a radiation thermometer while the recording medium was being moved using the drying transport mechanism of the Examples and Comparative Examples as the ink dried. The ink drying time was defined as the time required for the ink to dry at a constant rate. Figure 4 shows graphs of the ink temperature changes in Comparative Example 1 and Example 4, as well as the ink drying time for Comparative Example 1 and Example 4. Figure 5 shows graphs of the thermal conductivity of the protective sheet and the ink drying time. Table 1 shows the ink drying time and the temperature of each component in each drying transport mechanism.

[0067] [Table 1]

[0068] As shown in Table 1 and Figure 4 above, when the ink was dried by heating the belt only with the roller heating device without heating from the platen, the ink temperature rose slowly, and the drying time was about 1.8 seconds (Comparative Example 1). On the other hand, when heating was performed not only from the roller heating device but also from the heater provided in the platen using the drying and conveying mechanism of the present invention, as in the examples, the ink drying time was significantly faster, and it was possible to dry the ink in about 1 second (Example 4).

[0069] Furthermore, even when heating is performed using a platen, if the thermal conductivity of the protective sheet is less than 0.3 W / mK, the ink drying time becomes long, as shown in Figure 5 (Comparative Examples 2 and 3). In contrast, if the thermal conductivity of the protective sheet is 0.3 W / mK or higher, the ink drying time is significantly reduced, making it possible to dry the ink in a significantly shorter time (Examples 1 to 4). [Industrial Applicability]

[0070] The drying and conveying mechanism of the present invention can be used stably for a long period of time. Since the drying and conveying mechanism can also heat the back side of the recording medium, it is possible to dry or cure the ink efficiently in a short time to produce printed matter. Therefore, it is useful in various printing fields. [Explanation of symbols]

[0071] 1 Printing device 10 Recording media 11. Ink 100 Ink application section 110 Recording medium supply mechanism 120 Ink ejection section 130 Transportation 200 Drying section 210 Drying conveying mechanism 211 Platen 211a enclosure 211b Heater 211c void 211d Columnar part 211e Through hole 212 Suction plate 213 Protective Sheet 214 Belt 215 Suction part 220 Heat irradiation means 230 Convection means

Claims

1. a drying and transporting mechanism for transporting a recording medium when heating and drying and / or heating and curing ink applied to the recording medium; a platen having a built-in heater; an adsorption plate disposed on the platen for generating an adsorption pressure; a protective sheet placed on the adsorption plate and having a thermal conductivity of 0.3 W / mK or more; a belt disposed on the protective sheet for transporting the recording medium; and the platen has a housing that supports the heater; the housing has, on a side facing the suction plate, a plurality of pillars for supporting the suction plate and gaps formed between the pillars; the housing further has a through-hole communicating with the gap and for sucking gas from the adsorption plate side; Drying conveying mechanism.

2. The protective sheet contains glass fibers. The dry conveying mechanism according to claim 1 .

3. The opening ratio of the protective sheet is 10 to 50%. The dry conveying mechanism according to claim 2 .

4. The thermal conductivity of the adsorption plate is 5 W / mK or more. The drying and conveying mechanism according to any one of claims 1 to 3.

5. The adsorption plate has a porous shape, The average diameter of the pores of the adsorption plate is 10 μm or more and 100 μm or less. The drying and conveying mechanism according to any one of claims 1 to 4.

6. The thickness of the belt is 0.1 mm or more and 0.5 mm or less, The belt has a plurality of through holes penetrating in a thickness direction, The opening diameter of the through hole is 0.2 mm or more and 1 mm or less, The opening ratio of the belt is 2% or more and 20% or less. The drying and conveying mechanism according to any one of claims 1 to 5.

7. The belt comprises precipitation hardening stainless steel. The drying and conveying mechanism according to any one of claims 1 to 6.

8. The heater is an internal heater. The drying and conveying mechanism according to any one of claims 1 to 7.

9. an ink application unit for applying ink to a recording medium; The drying and conveying mechanism according to any one of claims 1 to 8, a printing device,

10. a drying unit disposed opposite the drying conveyance mechanism with the recording medium sandwiched therebetween, the drying unit heating the recording medium from the front surface side; The printing device of claim 9.

11. preparing a recording medium coated with ink; a step of drying and / or curing the ink while transporting the recording medium in a predetermined direction by the drying and transport mechanism according to any one of claims 1 to 8, In the step of drying and / or curing the ink, the back surface of the recording medium is attracted to the belt, and the recording medium is heated by the heater. Methods for producing printed materials.

12. In the step of drying and / or curing the ink, the recording medium is further heated by a drying means disposed on the surface side of the recording medium. The method for producing a printed matter according to claim 11.

13. The adsorption is started 0.4 seconds or more after the drying by the drying means has started. The method for producing a printed matter according to claim 12.

14. the temperature of the belt in the step of drying and / or curing the ink is 160°C or less; The method for producing a printed matter according to any one of claims 11 to 13.

15. The pressure during the adsorption is 3 to 20 kPa. The method for producing a printed matter according to any one of claims 11 to 14.

Images