Heating device, drying device, liquid ejection device

Abstract

To provide a device which improves drying efficiency.SOLUTION: A heater includes: first heating means 301 which heats a sheet material P to which liquid is given; second heating means 302 which is arranged on a downstream side in a sheet conveyance direction of the first heating means 301; and a suction conveyance mechanism section 303 which faces the second heating means 302 and conveys the sheet material P. A portion on an upstream side of the second heating means 302 in a conveyance belt 331 of the suction conveyance mechanism section 303 is used also as transfer means for transferring the sheet material P toward the second heating means 302. The heater further includes heating control means 901 which causes the first heating means 301 to selectively heat the sheet material P on the upstream side of the transfer means (conveyance belt 331) or the sheet material P transferred by the portion used also as the transfer means in the conveyance belt 331 on the basis of information on the sheet material P.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a heating device, a drying device, and an apparatus for discharging liquid. [Background technology]

[0002] 2. Description of the Related Art Among devices equipped with a means for ejecting a liquid, there is one equipped with a drying device including a heating means for heating a sheet material (a member to which the liquid has been applied) to which the liquid has been applied.

[0003] Conventionally, there is known a device that includes a first heating means for heating a sheet material to which liquid has been applied, a suction and conveying means for sucking and conveying the sheet material that has passed through the first heating means, and a second heating means for heating the sheet material being conveyed by the suction and conveying means (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-035761 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even in an apparatus such as that disclosed in Patent Document 1, there is a problem in that further improvement in drying efficiency is required.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to improve drying efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the heating device according to the present invention comprises: A first heating means for heating the sheet material to which the liquid has been applied; A second heating means disposed downstream of the first heating means in a sheet conveying direction; a transfer means for transferring the sheet material toward the second heating means; Equipped with the first heating means is capable of changing a heating direction between a direction for heating the sheet material upstream of the transport means and a direction for heating the sheet material being transported by the transport means; The heating direction of the first heating means is Based on the information regarding the sheet material ,before The sheet material on the upstream side of the conveying means Heating direction or the sheet material being transported by the transport means A means for controlling the direction of heating Equipped with The composition was as follows.

[0008] According to the present invention, the drying efficiency is improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of a printing apparatus that is an apparatus for ejecting liquid according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view illustrating an example of a discharge unit of the printing apparatus; [Diagram 3] FIG. 1 is an illustrative side view of a heating device according to a first embodiment of the present invention. [Figure 4] FIG. 13 is a perspective view illustrating a different example of a conveyor belt. [Diagram 5] FIG. 2 is a block diagram of a portion relating to heating control in the heating device according to the first embodiment of the present invention. [Figure 6] FIG. 4 is an explanatory diagram of an example of a table stored in a storage unit. [Figure 7] 4 is a flow diagram illustrating heating direction (posture) control of the first heating means by the heating control means. FIG. [Figure 8] 10 is an explanatory diagram of a transition of ink temperature at a sheet material conveying position, illustrating an example of a relationship between the heating direction of a first heating means and a transition of temperature of liquid (ink) on a sheet material. FIG. [Figure 9] FIG. 11 is a schematic explanatory diagram of a printing apparatus which is an apparatus for discharging liquid according to a second embodiment of the present invention. [Figure 10] FIG. 11 is a block diagram of a portion relating to heating control in a heating device according to a second embodiment of the present invention. [Figure 11]FIG. 4 is an explanatory diagram of an example of a table stored in a storage unit. [Figure 12] 4 is a flow diagram illustrating heating direction (posture) control of the first heating means by the heating control means. FIG. [Figure 13] FIG. 11 is an explanatory diagram illustrating a heating device according to a third embodiment of the present invention. [Figure 14] FIG. 11 is an illustrative side view of a heating device according to a fourth embodiment of the present invention. [Figure 15] FIG. 13 is an explanatory side view of a portion of a first heating means of a heating device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, a printing apparatus, which is an apparatus for discharging liquid according to a first embodiment of the present invention, will be described with reference to Figures 1 and 2. Figure 1 is a schematic explanatory diagram of the printing apparatus, and Figure 2 is a plan explanatory diagram of an example of a discharge unit of the printing apparatus.

[0011] The printing device 1 includes an input section 10, a printing section 20, a drying section 30, and an unloading section 40. In the printing device 1, the printing section 20 applies liquid to the sheet material P loaded from the input section 10 to perform a required printing, and the drying section 30 dries the liquid adhering to the sheet material P, and then the sheet material P is discharged to the unloading section 40.

[0012] The operation unit 80 inputs printing conditions and the like to the printing device 1. The control unit 91 of the control device 90 controls the printing operation and the like based on the input from the operation unit 80 and a table of operations corresponding to the setting contents stored in the storage unit 92.

[0013] The carry-in section 10 includes an input tray 11 on which a plurality of sheet materials P are stacked, and a feed device 12 that separates and feeds the sheet materials P from the input tray 11 one by one.

[0014] Any feeding device can be used as the feeding device 12, such as a device using rollers or a device using air suction. The sheet material P fed from the input tray 11 by the feeding device 12 is fed to the printing unit 20.

[0015] The printing section 20 includes a pair of registration rollers 21 that are driven at a predetermined timing to feed out the sheet material P after the sheet material P sent out from the carry-in section 10 arrives at the printing section 20.

[0016] The printing unit 20 also includes a sheet conveying device 22 that conveys the sheet material P. The sheet conveying device 22 includes a drum 23 that is a support member (rotating member) that supports the sheet material P on its circumferential surface and rotates, and a suction device 24 that is a suction means that generates a suction force on the circumferential surface of the drum 23.

[0017] The printing unit 20 also includes a liquid ejection unit 25 that ejects and applies liquid to the sheet material P supported and transported by the drum 23 of the sheet transport device 22.

[0018] The printing section 20 also includes a transfer cylinder 26 that receives the fed sheet material P and transfers the sheet material P between the drum 23, and a transfer cylinder 27 that transfers the sheet material P transported by the drum 23 to the drying section 30.

[0019] The sheet material P conveyed from the carry-in section 10 to the printing section 20 is sent to the transfer drum 26 at a predetermined timing by the pair of registration rollers 21, and its leading edge is gripped by a gripping means (gripper) provided on the transfer drum 26 and conveyed as the transfer drum 26 rotates. The sheet material P conveyed by the transfer drum 26 is delivered to the drum 23 at a position opposite to the drum 23.

[0020] A gripping means (gripper) is provided on the surface of the drum 23, and the leading end of the sheet material P is gripped by the gripper. A plurality of suction holes are formed and dispersed on the surface of the drum 23. A suction device 24 generates a suction airflow that flows inward from the required suction holes of the drum 23.

[0021] Then, the sheet material P transferred from the transfer cylinder 26 to the drum 23 has its leading edge gripped by the gripper, and is adsorbed and supported on the drum 23 by the suction airflow of the suction device 24, and is transported as the drum 23 rotates.

[0022] The liquid discharge section 25 includes discharge units 28 (28A to 28F) which are liquid application means. For example, the discharge unit 28A discharges black (K) liquid, the discharge unit 28B discharges cyan (C) liquid, the discharge unit 28C discharges magenta (M) liquid, and the discharge unit 28D discharges yellow (Y) liquid.

[0023] Moreover, the ejection units 28E and 28F are used to eject any of YMCK, or special liquids such as white, gold (silver), etc. Furthermore, an ejection unit that ejects a processing liquid such as a surface coating liquid can also be provided.

[0024] The ejection unit 28 is, for example, a full-line type head in which multiple liquid ejection heads (hereinafter simply referred to as "heads") 100, each having a nozzle row 101 in which multiple nozzles are arranged, are arranged on a base member 102, as shown in FIG.

[0025] The ejection operation of each ejection unit 28 of the liquid ejection section 25 is controlled by a drive signal corresponding to print information.

[0026] When the sheet material P supported on the drum 23 passes through an area facing the liquid ejection section 25, liquid of each color is ejected from the ejection unit 28, and an image according to the printing information is printed.

[0027] The sheet material P to which the liquid has been applied by the liquid discharger 25 is sent from the surface of the drum 23 to a transfer cylinder 27 which is a transfer rotor.

[0028] A gripping means (gripper) for gripping the leading edge of the sheet material P is also provided on the surface of the transfer cylinder 27, and the leading edge of the sheet material P is transferred from the gripper of the drum 23 to the gripper of the transfer cylinder 27, thereby transferring the sheet material P from the surface of the drum 23 to the transfer cylinder 27.

[0029] Then, the sheet material P is delivered to the suction transport mechanism 33 of the drying section 30 via the peripheral surface (delivery path) of the delivery drum 27 by the rotation of the delivery drum 27 .

[0030] Here, a first drying means 31 for drying the sheet material P is disposed between the printing section 20 and the drying section 30, so that the liquid adhered to the sheet material P in the printing section 20 can be heated and dried by the first drying means 31.

[0031] The drying section 30 includes a second drying means 32 that heats and dries the liquid on the sheet material P, and a suction conveying mechanism section 33 which is a conveying means that conveys (suction conveys) the sheet material P handed over from the transfer cylinder 27 of the printing section 20 in a suction state.

[0032] The sheet material P to which the liquid has been applied in the printing unit 20 is heated by the first drying means 31 when it is transferred to the suction transport mechanism 33 by the transfer drum 27, and is further heated by the second drying means 32 while being transported by the suction transport mechanism 33, and is sent to the discharge unit 40. Note that the inside of the transfer drum 27 may be hollow or mesh-like, so that the sheet material P to which the liquid has been applied can be directly dried by the heating of the first drying means 31.

[0033] When passing through the second drying means 32, the liquid on the sheet material P that has been heated (pre-heated) by the first drying means 31 is further subjected to a heat treatment.

[0034] As a result, the liquid components such as water in the liquid evaporate, the colorant contained in the liquid is reliably fixed onto the sheet material P, and curling of the sheet material P is suppressed.

[0035] The discharge section 40 includes a discharge tray 41 on which a plurality of sheet materials P are stacked. The sheet materials P conveyed from the drying section 30 are successively stacked and held on the discharge tray 41.

[0036] Here, the ink used as the liquid in the printing device 1 will be described.

[0037] The ink of this embodiment is a water-based ink, and contains an organic solvent, water, a coloring material, a resin, and additives.

[0038] <Ink> The organic solvent, water, coloring material, resin, additives, etc. used in the ink will be described below. <Organic solvent> The organic solvent is not particularly limited, and any water-soluble organic solvent can be used. Examples of the organic solvent include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

[0039] It is preferable to use an organic solvent having a boiling point of 250° C. or less, since this not only functions as a wetting agent but also provides good drying properties.

[0040] The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of the drying property and ejection reliability of the ink, however, the content is preferably from 10% by mass to 60% by mass, and more preferably from 20% by mass to 60% by mass.

[0041] <Water> The water content in the ink is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of the drying property and ejection reliability of the ink, however, it is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass to 60% by mass.

[0042] <Coloring material> The coloring material is not particularly limited, and a pigment is used.

[0043] As the pigment, an inorganic pigment or an organic pigment can be used. These pigments can be used alone or in combination of two or more. Also, mixed crystals can be used as the pigment.

[0044] The content of the coloring material in the ink is preferably from 0.1% to 15% by mass, and more preferably from 1% to 10% by mass, from the viewpoints of improving image density, good fixing property and ejection stability.

[0045] Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.

[0046] <Resin> The type of resin contained in the ink is not particularly limited and can be appropriately selected depending on the purpose. Examples of the resin include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin.

[0047] The content of the resin is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of fixability and storage stability of the ink, the content of the toner is preferably from 1% by mass to 30% by mass, and more preferably from 5% by mass to 20% by mass, based on the total amount of the ink.

[0048] <Additives> If necessary, surfactants, antifoaming agents, antiseptics, antifungals, rust inhibitors, pH adjusters, etc. may be added to the ink.

[0049] Next, a heating device according to a first embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a side view of the heating device according to the first embodiment, and Fig. 4 is a perspective view of a different example of a conveyor belt.

[0050] The heating device 300 also serves as a drying device, and is equipped with a first heating means 301, a second heating means 302 arranged downstream of the first heating means 301 in the sheet material transport direction, and a suction transport mechanism section 303 serving as a transfer means and a transport means.

[0051] The first heating means 301 includes one or more hot air blowing means 311 including, for example, an infrared heater capable of radiating heat transfer and a blowing means. The first heating means 301 is not limited to the hot air blowing means 311, and may be an infrared ray irradiation means such as an IR heater, a near-infrared ray irradiation means, or a combination of these. The first heating means 301 serves as the first drying means 31.

[0052] The second heating means 302 includes, for example, one or more hot air blowing means 321 arranged along the conveyance path in a housing 320. The second heating means 302 serves as the second drying means 32. The second heating means 302 may be an infrared ray irradiation means such as an IR heater, a near-infrared ray irradiation means, an ultraviolet ray irradiation means, or a combination of these.

[0053] The suction conveying mechanism 303 includes a conveying belt 331 that adsorbs and conveys the sheet material P delivered from the delivery drum 27. The conveying belt 331 is stretched between a driving roller 332 and a driven roller 333, and moves in a circular motion by driving the driving roller 332.

[0054] In this embodiment, the conveyor belt 331 of the suction conveying mechanism 303 is disposed across from the delivery cylinder 27 to the second heating means 302. As a result, the conveyor belt 331 serves both as a conveying means for conveying the sheet material P facing the second heating means 302 and as a transporting means for transferring the sheet material P to the conveying means in a portion upstream of the second heating means 302.

[0055] Here, the conveyor belt 331 has a ventilation structure with a plurality of through holes (suction holes) distributed on its surface. In addition, a suction chamber 334 serving as a suction mechanism is disposed inside the conveyor belt 331, and the sheet material P is attracted to the conveyor belt 331 by suctioning the inside of the suction chamber 334.

[0056] For example, a mesh belt made of glass fiber can be used for the conveyor belt 331. The mesh belt is, for example, a mesh of linear members arranged in a mesh pattern as shown in Fig. 4(a). By using the mesh belt, it is possible to reduce flapping of the sheet material P caused by rebounding of the hot air blown by the hot air blowing means 321.

[0057] The conveyor belt 331 may have suction holes (suction openings) formed on the surface, and may be configured to support the sheet material P with a plurality of support wires 331a as shown in Fig. 4(b) or may be made of a porous material. The suction openings are not limited to a rectangular shape, and may be circular, for example.

[0058] The amount of heat applied to the sheet material P by the second heating means 302 is set to be greater than the amount of heat applied to the sheet material P by the first heating means 301 .

[0059] In this manner, by further heating the sheet material P heated by the first heating means 301 by the second heating means 302, the liquid applied to the sheet material P can be reliably dried.

[0060] The first heating means 301 is disposed so that the heating direction (the blowing direction of radiant heat from the first heating means 301) can be changed. That is, the first heating means 301 can be changed between a position in which the heating direction is direction A as shown in Fig. 3(a) (the position shown by the solid line in Fig. 1) and a position in which the heating direction is direction B as shown in Fig. 3(b) (the position shown by the virtual line in Fig. 1).

[0061] When the first heating means 301 is oriented so that the heating direction is in the direction A, the sheet material P is heated upstream of the conveyor belt 331 which also serves as the transfer means. In other words, the sheet material P is heated before it is handed over from the delivery drum 27 to the part of the conveyor belt 331 which serves as the transfer means.

[0062] When the first heating means 301 is oriented so that the heating direction is in the direction B, the sheet material P that has been transferred from the delivery drum 27 to the conveyor belt 331 and is not facing the second heating means 302 is heated. In other words, the sheet material P that is being transferred at the portion of the conveyor belt 331 that serves as the transfer means is heated before the entrance of the second heating means 302.

[0063] Next, the portion relating to heating control in the heating device according to the first embodiment of the present invention will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a block diagram of the portion relating to the control, and Fig. 6 is an explanatory diagram of an example of a table stored in the storage means.

[0064] The operation means 801 can input information on the basis weight or thickness of the sheet material P. The information on the basis weight or thickness of the sheet material P is information related to the sheet material P.

[0065] The operation means 801 can be configured, for example, by an operation panel (operation screen) of the operation unit 80 provided in the printing device 1, or a print instruction terminal (for example, a computer) connected to the printing device 1.

[0066] As shown in FIG. 6, the storage unit 902 stores a table that lists the relationship between the information on the basis weight or thickness of the sheet material P and the heating direction of the first heating unit 301.

[0067] In this embodiment, when the basis weight of the sheet material P is equal to or less than a predetermined value, the basis weight is "small," and when the basis weight is greater than the predetermined value, the basis weight is "large." For example, when the basis weight of the sheet material P is equal to or less than 150 gsm, the basis weight is small, and when the basis weight is greater than 150 gsm, the basis weight is large. In addition, when the thickness of the sheet material P is used as the standard, for example, when the thickness is 0.17 mm or less, the sheet material is considered to be "thin paper," and when the thickness is greater than 0.17 mm, the sheet material is considered to be "thick paper."

[0068] When the basis weight is small (thin paper), the heating direction (posture) of the first heating means 301 is set to direction A, which heats the sheet material before it is handed over to the conveying belt 331, and when the basis weight is large (thick paper), the heating direction (posture) of the first heating means 301 is set to direction B, which heats the sheet material just before the entrance of the second heating means 302 and is being conveyed by the conveying belt 331.

[0069] The heating control means 901 reads out a table from the storage means 902 based on information on the basis weight or thickness of the sheet material P input from the operation means 801, and drives and controls the heating direction driving unit 315 to control the heating direction (posture) of the first heating means 301. In other words, the heating control means 901 is a means for selectively heating, based on information on the sheet material P, the sheet material P upstream of the conveyor belt 331 serving as the transport means, or the sheet material P being transported by the transport means, by the first heating means 301.

[0070] The heating control means 901 also controls the heating of the sheet material P by the first heating means 301 and the heating of the sheet material P by the second heating means 302.

[0071] Next, the heating direction (posture) control of the first heating means 301 by the heating control means 901 will be described with reference to the flow chart of FIG.

[0072] An operator sets the basis weight or thickness of the sheet material P using the operation means 801 (step S1, hereinafter simply referred to as "S1"). Note that in FIG.

[0073] The heating control means 901 takes in information on the basis weight or thickness of the sheet material P set by the operation means 801, and reads the table stored in the storage unit 92 (S2).

[0074] Then, the heating control means 901 controls the driving of the heating direction driving section 315 based on the read table, and switches the heating direction of the first heating means 301 .

[0075] That is, the heating control means 901 judges whether the sheet material P is thin paper or thick paper (S3).

[0076] Here, when the sheet material P is thin paper, the heat control means 901 sets the heating direction of the first heating means 301 to the direction A, that is, the direction in which the sheet material P before being handed over to the conveyor belt 331 is heated (S4).

[0077] In contrast, when the sheet material P is cardboard, the heating control means 901 sets the heating direction of the first heating means 301 to direction B, i.e., the direction just before the entrance of the second heating means 302, to heat the sheet material P being transported by the transport belt 331 (S5).

[0078] Next, an example of the relationship between the heating direction of the first heating means and the transition of the liquid temperature (here, the ink temperature) on the sheet material will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram of the transition of the ink temperature at the sheet material conveying position for the description.

[0079] First, when the heating direction of the first heating means 301 is set to direction A, the change in the ink temperature is shown by the dashed dotted line in FIG.

[0080] That is, when the heating direction of the first heating means 301 is direction A, the sheet material P is heated when it passes through the transfer cylinder 27 on the upstream side of the conveyor belt 331. Therefore, the ink temperature rises when the sheet material P passes through the transfer cylinder 27, and after it passes through the transfer cylinder 27 and is handed over to the conveyor belt 331, the ink temperature drops once before the sheet material P reaches the entrance of the second heating means 302. Thereafter, as the sheet material P is conveyed by the conveyor belt 331 facing the second heating means 302, the ink temperature rises and reaches a peak temperature near the exit of the second heating means 302.

[0081] In this manner, the sheet material P is heated by the first heating means 301 before being placed on the conveyor belt 331, and then heated by the second heating means 302 after the ink temperature has temporarily dropped.

[0082] Here, since the conveyor belt 331 faces the hot air blowing means 321, the temperature of the belt surface (the surface that comes into contact with the sheet material P) rises, but since the air intake opening of the conveyor belt 331 is a space, the temperature does not rise like the belt surface.

[0083] Therefore, when the sheet material P is placed on the belt surface of the conveyor belt 331 while the water-based liquid (ink) is not yet completely dry, the pigment in the ink on the sheet material P flows due to the temperature difference between the belt surface and the intake opening, and a pattern (color unevenness) corresponding to the shape of the net of the mesh belt, for example, appears in the image. Color unevenness occurs particularly when the sheet material P is thin or coated paper (a sheet with a surface coated with paint to enhance smoothness) with a small basis weight.

[0084] Therefore, as in this embodiment, the flow of ink can be suppressed by performing heating (pre-drying) by the first heating means 301 before heating (main drying) by the second heating means 302 on the conveyor belt 331. This makes it possible to prevent abnormal images in which traces of suction openings such as suction holes in the conveyor belt 331 (for example, mesh marks) appear on the image.

[0085] In other words, when a water-based liquid (ink) is applied to a sheet material and the sheet material P is dried while being adsorbed and transported by a transport belt such as a mesh belt having suction openings, the occurrence of abnormal images can be prevented by performing pre-drying before the sheet material P is placed on the transport belt.

[0086] Next, when the heating direction of the first heating means 301 is set to direction B, the change in the ink temperature is shown by the solid line in FIG.

[0087] That is, when the heating direction of the first heating means 301 is set to direction B, the ink temperature rises when the sheet material P passes through the delivery cylinder 27, is handed over to the conveyor belt 331, and is conveyed to just before the entrance of the second heating means 302. Then, as the sheet material P with the increased ink temperature is conveyed by the conveyor belt 331 facing the second heating means 302, the ink temperature rises further and reaches a peak temperature near the exit of the second heating means 302.

[0088] In this way, since the ink temperature of the sheet material P is increased when it enters the second heating means 302, the peak temperature of the ink temperature near the exit of the second heating means 302 is higher than the peak temperature when the heating direction of the first heating means 301 is set to direction A. As a result, when the heating direction of the first heating means 301 is set to direction B, evaporation of moisture is promoted more than when it is set to direction A.

[0089] Here, in the relationship between the heating direction of the first heating means 301 and the basis weight or thickness of the sheet material, when the sheet material P is thick paper, the temperature difference between the belt surface and the suction opening on the back surface of the sheet material P is equalized before being transmitted to the ink layer on the front surface of the sheet material P.

[0090] Therefore, since no ink flow occurs on the surface of the sheet material P, heating in direction A by the first heating means 301 is not necessary. Therefore, by heating in direction B by the first heating means 301, which can promote evaporation, it becomes possible to dry the cardboard in a space-saving manner without increasing the number of heaters. Note that when the sheet material P is thin paper, it does not require as much heat as thick paper, so it can be dried by heating only by the second heating means 302.

[0091] In this way, for thin paper (sheet material P in which color unevenness occurs due to uneven heating) in which temperature unevenness of the conveying belt 331 is easily transmitted to the ink on the sheet material P, the first heating means 301 is set in direction A to heat (pre-dry) the sheet material P.

[0092] For thin paper, by heating the sheet material P using the first heating means 301 before it is placed on the conveyor belt 331, it is possible to suppress uneven drying, uneven gloss, and uneven images caused by the movement of pigment on the surface of the sheet material P to which the printing liquid has been applied.

[0093] On the other hand, even if there is temperature unevenness in the conveying belt 331, the temperature difference is mitigated while heat is transferred through the sheet material P, and for thick paper (sheet material P in which color unevenness due to uneven heating does not occur) on which temperature differences are unlikely to be applied to the ink on the sheet material P, heating is performed by setting the first heating means 301 in the direction B.

[0094] By heating the sheet material P with the second heating means 302 immediately after heating with the first heating means 301, the peak temperature of the ink can be increased and drying can be promoted. In this way, when the sheet material is thick paper (having a large basis weight), by utilizing the heating of the first heating means 301, the thick paper can be dried efficiently in a small space without increasing the number of heaters of the second heating means 302, and the drying efficiency of the thick paper is improved.

[0095] Next, the heating direction of the first heating means and the transport distance of the sheet material after heating by the first heating means until heating by the second heating means is started will be described with reference to FIG.

[0096] As shown in FIG. 3(a), when heating is performed with the first heating means 301 in the direction A, the transport distance of the sheet material P after being heated by the first heating means 301 until it is heated by the second heating means 302 is, for example, the distance from the transfer position from the transfer drum 27 to the position where it is heated by the hot air blowing means 321 at the most upstream of the second heating means 302.

[0097] On the other hand, as shown in Figure 3 (b), when heating is performed with the first heating means 301 in direction B, the transport distance of the sheet material P after being heated by the first heating means 301 until it is heated by the second heating means 302 is, for example, the distance from the position where it is heated by the most downstream hot air blowing means 311 of the first heating means 301 to the position where it is heated by the most upstream hot air blowing means 321 of the second heating means 302.

[0098] In other words, when heating of the sheet material P by the first heating means 301 is started upstream of the transport means, the transport distance over which the sheet material P is heated by the first heating means 301 and then by the second heating means 302 is longer than when heating is started after the transport means has begun to transport the sheet material.

[0099] Next, a printing apparatus, which is an apparatus for discharging liquid according to a second embodiment of the present invention, will be described with reference to Fig. 9. Fig. 9 is a schematic explanatory diagram of the printing apparatus.

[0100] In the printing apparatus 1 of this embodiment, in addition to the configuration of the printing apparatus 1 of the first embodiment, a pre-treatment section 50 serving as liquid application means for applying treatment liquid to the sheet material P is disposed upstream of the printing section 20 on the transport path.

[0101] The pre-treatment section 50 includes a treatment liquid container 55 that contains treatment liquid 54, a pumping roller 51 that pumps up the treatment liquid 54, an application roller 52 that applies (applies) the treatment liquid 54 to the sheet material P, and an opposing roller 53 that faces the application roller 52 with the sheet material P sandwiched therebetween. The treatment liquid 54 may be a treatment liquid that reacts with liquid to suppress bleeding.

[0102] After the treatment liquid 54 is applied to the lower surface of the sheet material P by the application roller 52, the sheet material P is turned upside down and conveyed to the pair of registration rollers 21. The sheet material P that has passed through the pair of registration rollers 21 is conveyed so that the surface to which the treatment liquid 54 has been applied faces the discharge unit 28, and the liquid is applied from the discharge unit 28.

[0103] Next, the portion relating to heating control in the heating device according to the second embodiment of the present invention will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a block diagram of the portion relating to the control, and Fig. 11 is an explanatory diagram of an example of a table stored in a storage means.

[0104] In this embodiment, the operation means 801 is used to input information on the basis weight or thickness of the sheet material P to be used, similarly to the first embodiment.

[0105] The liquid application setting means 802 sets the application (presence or absence of application, application amount) of the treatment liquid by the pre-treatment unit 50. In this embodiment, information on the presence or absence of application of the treatment liquid 54 set by the application setting means 802 is provided to the heating control means 901 as information on the sheet material P.

[0106] As shown in FIG. 11, the memory means 902 stores a table which lists information on whether or not the treatment liquid 54 has been applied to the sheet material P, information on the basis weight or thickness of the sheet material P, and information on the heating direction of the first heating means 301.

[0107] In this embodiment, when no coating is performed, similarly to the first embodiment, when the basis weight is small (thin paper), the heating direction of the first heating means 301 is direction A, and when the basis weight is large (thick paper), the heating direction of the first heating means 301 is direction B. When coating is performed, the heating direction of the first heating means 301 is direction B regardless of the basis weight (thickness).

[0108] The heating control means 901 reads out a table from the memory means 902 based on information on the basis weight or thickness of the sheet material P input from the operation means 801 and information on whether or not to apply coating input from the application setting means 802, and drives and controls the heating direction driving unit 315 to control the heating direction (posture) of the first heating means 301.

[0109] The heating control means 901 also controls the heating of the sheet material P by the first heating means 301 and the heating of the sheet material P by the second heating means 302.

[0110] The coating control means 903 controls the coating operation by the coating means 501 (pre-treatment unit 50 ) when coating the treatment liquid 54 in accordance with the settings of the coating setting means 802 .

[0111] Next, the heating direction (posture) control of the first heating means 301 by the heating control means 901 will be described with reference to the flow chart of FIG.

[0112] The operator sets whether or not coating is performed using the coating setting means 802 (S11), and then sets the basis weight or thickness of the sheet material P using the operation means 801 (S12).

[0113] The heating control means 901 takes in the information on whether or not to apply coating set by the coating setting means 802 and the information on the basis weight or thickness of the sheet material P set by the operation means 801, and reads the table stored in the memory unit 92 (S13).

[0114] Then, the heating control means 901 switches the heating direction of the first heating means 301 by the heating direction driving section 315 based on the read table.

[0115] That is, the heating control means 901 judges whether application is performed or not (S14).

[0116] At this time, if no coating is found, it is determined whether the sheet material P is thin paper or thick paper (S15).

[0117] Here, when the sheet material P is thin paper, the heat control means 901 sets the heating direction of the first heating means 301 to the direction A, that is, the direction in which the sheet material P is heated before being passed to the conveyor belt 331 (S16).

[0118] In contrast, when the sheet material P is cardboard, the heating control means 901 sets the heating direction of the first heating means 301 to direction B, i.e., the direction just before the entrance of the second heating means 302, to heat the sheet material P being transported by the transport belt 331 (S17).

[0119] Also, if coating is present, the process proceeds to step S17, and the heating control means 901 sets the heating direction of the first heating means 301 to direction B, i.e., the direction just before the entrance of the second heating means 302, in which the sheet material P being transported by the transport belt 331 is heated.

[0120] In this way, when coating is performed, the heating direction of the first heating means 301 is set to the B direction regardless of the basis weight or thickness of the sheet material P.

[0121] In other words, when the treatment liquid 54 is applied, the ink applied to the sheet material P has a characteristic of being less likely to flow, so the color unevenness described above does not occur whether the paper is thick or thin. Instead, the amount of liquid on the sheet material P increases by the amount of treatment liquid 54 applied, so the amount of drying heat tends to increase.

[0122] Therefore, the heating direction of the first heating means 301 is set to the direction B, and the sheet material P being conveyed by the conveyor belt 331 is heated just before the inlet of the second heating means 302, and immediately thereafter, heating by the second heating means 302 is performed. This makes it possible to increase the peak temperature of the ink and promote drying.

[0123] Next, a heating device according to a third embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is an explanatory diagram for explaining the heating device.

[0124] In this embodiment, a conveying belt 331 is provided as a conveying means for conveying the sheet material P opposite the second heating means 302, and a conveying means 304 is provided on the upstream side of the conveying belt 331 in the sheet material conveying direction, for conveying the sheet material P toward the conveying belt 331.

[0125] The transfer means 304 includes a delivery conveyor belt 341 as a delivery conveyor means disposed between the delivery drum 27 and the conveyor belt 331. The delivery conveyor belt 341 is stretched between a drive roller 342 and a driven roller 343, and moves in a circular motion by driving the drive roller 342. The delivery belt 341 can convey the sheet material P by sucking or adsorbing it. The delivery belt 341 may have the same configuration as the conveyor belt 331.

[0126] Also in this embodiment, the first heating means 301 is arranged so that the heating direction (the blowing direction of radiant heat from the first heating means 301) can be changed. That is, the first heating means 301 can be changed between a position in which the heating direction is direction A as shown in Fig. 13(a) (the position shown by the solid line in Fig. 1) and a position in which the heating direction is direction B as shown in Fig. 13(b) (the position shown by the virtual line in Fig. 1).

[0127] When the first heating means 301 is oriented so that the heating direction is in the direction A, the sheet material P is heated upstream of the transport means 304. In other words, the sheet material P before being transferred from the delivery drum 27 to the transport means 304 is heated.

[0128] When the first heating means 301 is oriented so that the heating direction is in the direction B, the sheet material P is heated after being transferred from the transfer cylinder 27 to the transfer conveyor belt 341 of the transfer means 304 and before it faces the second heating means 302. In other words, the sheet material P being transferred by the transfer means 304 is heated before the entrance of the second heating means 302.

[0129] Next, a heating device according to a fourth embodiment of the present invention will be described with reference to Fig. 14. Fig. 14 is an explanatory side view of the heating device.

[0130] The heating device 300 has, as the second heating means 302, a heat irradiation section 302A and an ultraviolet ray irradiation section 302B.

[0131] In the heat irradiation unit 302A, a plurality of heat irradiation means 322A composed of IR heaters are arranged along the conveying direction inside the housing 320A. The heat irradiation means 322A irradiates infrared rays to heat the sheet material P conveyed by the suction conveying mechanism 303. The heat irradiation unit 302A includes a temperature detection means 323A that detects the temperature of the heat irradiation means 322A.

[0132] The ultraviolet ray irradiation unit 302B has a plurality of ultraviolet ray irradiation means 322B arranged in the conveying direction inside a housing 320B. The ultraviolet ray irradiation means 322B irradiates the sheet material P conveyed by the suction conveying mechanism 303 with ultraviolet rays to heat it.

[0133] In this manner, in the conveying direction of the sheet material P, the heat irradiation means 322A is disposed on the upstream side, and the ultraviolet ray irradiation means 322B is disposed on the downstream side.

[0134] Next, a heating device according to a fifth embodiment of the present invention will be described with reference to Fig. 15. Fig. 15 is a side view illustrating a portion of a first heating means of the heating device.

[0135] The hot air blowing means 311 of the first heating means 301 includes an infrared heater 312 capable of radiating heat transfer, an air blowing means 313 such as a fan, and an air blowing guide 314 forming an air outlet.

[0136] The air blowing guide 314 can be displaced between the position shown by the solid line and the position shown by the virtual line. When the air blowing guide 314 is in the position shown by the solid line, the heating direction (hot air blowing direction) is direction A, and when it is in the position shown by the virtual line, the heating direction (hot air blowing direction) is direction B.

[0137] That is, in this embodiment, instead of changing the attitude of the entire first heating means 301, the heating direction is switched by changing the hot air blowing direction by the air blowing guide (blowout guiding means) 314.

[0138] In this way, the heating direction can be easily changed. [Explanation of symbols]

[0139] 1 Printing device 10 Loading section 20 Printing Department 21 Sheet transport device 25 Liquid discharge part 27 Delivery Body 28 Discharge unit 30 Drying section 31 First drying means (first heating means) 32 Second drying means (second heating means) 33 Suction transport mechanism 300 Heating device 301 First heating means 302 Second heating means 303 Suction and transport mechanism 304 Transport means 331 Conveyor Belt

Claims

1. A first heating means for heating the sheet material to which the liquid has been applied; A second heating means disposed downstream of the first heating means in a sheet conveying direction; a transport means for transporting the sheet material toward the second heating means, the first heating means is capable of changing a heating direction between a direction for heating the sheet material upstream of the transport means and a direction for heating the sheet material being transported by the transport means, The heating means includes a control means for controlling the heating direction of the first heating means based on information about the sheet material, so as to heat the sheet material upstream of the transport means or to heat the sheet material being transported by the transport means. A heating device characterized by:

2. The conveying means also serves as a conveying means for conveying the sheet material opposite to the second heating means.

2. The heating device according to claim 1 .

3. The transfer means is a delivery conveying means that conveys the sheet material toward the conveying means, the delivery means being located upstream in a sheet material conveying direction of the conveying means that conveys the sheet material opposite to the second heating means.

2. The heating device according to claim 1 .

4. The information regarding the sheet material is the thickness or basis weight of the sheet material.

4. The heating device according to claim 1, wherein the heating device is a heater.

5. The information regarding the sheet material is information regarding whether or not a treatment liquid is applied to the sheet material.

5. The heating device according to claim 1, wherein the heating device is a heater.

6. The means for controlling When the treatment liquid is being applied, the heating direction of the first heating means is set to a direction in which the sheet material being transported by the transport means is heated; When the treatment liquid is not applied, the heating direction of the first heating means is set to a direction for heating the sheet material upstream of the transport means, or a direction for heating the sheet material being transported by the transport means, based on the thickness or basis weight of the sheet material. Take control 6. The heating device according to claim 5.

7. The first heating means is capable of changing its position.

7. The heating device according to claim 1, wherein the heating device is a heater.

8. The first heating means includes a heat generating means and an air blowing means, and is capable of changing the blowing direction.

7. The heating device according to claim 1, wherein the heating device is a heater.

9. The means for controlling changes whether heating of the sheet material by the first heating means is started upstream of the transport means or after the transport means starts transporting the sheet material, based on information about the sheet material.

9. The heating device according to claim 1, wherein the heating device is a heater.

10. When the heating of the sheet material by the first heating means is started upstream of the transport means, the liquid temperature of the sheet material is temporarily lowered until the sheet material is transported to the second heating means.

10. The heating device according to claim 9.

11. When the heating of the sheet material by the first heating means is started after the transporting means starts transporting the sheet material, the liquid temperature of the sheet material after heating by the second heating means becomes higher than when the heating is started upstream of the transporting means.

11. The heating device according to claim 10.

12. When the heating of the sheet material by the first heating means is started upstream of the transport means, the transport distance of the sheet material from being heated by the first heating means to being heated by the second heating means is longer than when the heating is started after the transport means has started to transport the sheet material.

12. The heating device according to claim 9, wherein the heating device is a heater.

13. Equipped with the heating device according to any one of claims 1 to 12 A drying device characterized by:

14. A liquid application means for applying a liquid to the sheet material; The heating device according to any one of claims 1 to 12 or the drying device according to claim 13 is provided. A liquid ejection device comprising:

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