Drying device and printing system

Abstract

To provide a drying device that can effectively dry a medium, and a printing system.SOLUTION: A drying device comprises a drying furnace which a conveyed medium 99 intrudes into, and a heating part 48 that heats the medium in the drying furnace. The heating part has an upstream heating mechanism 55, a downstream heating mechanism 56 positioned closer to a downstream side than the upstream heating mechanism in a conveying direction D1 of the medium, and an intermediate heating mechanism 57 positioned between the upstream heating mechanism and the downstream heating mechanism in the conveying direction. The upstream heating mechanism has an upstream heating member positioned so that a distance from the medium is equal to a predetermined distance. The downstream heating mechanism has a downstream heating member positioned so that a distance from the medium becomes larger than the predetermined distance. The intermediate heating mechanism has an intermediate heating member positioned so that a distance from the medium becomes larger than the predetermined distance. A set temperature of the upstream heating member is higher than a set temperature of the intermediate heating member, and a set temperature of the downstream heating member is higher than a set temperature of the intermediate heating member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drying device and a printing system. [Background technology]

[0002] Patent Document 1 describes a drying device that heats a medium using a heating unit. The drying device dries the medium by heating the medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-2473 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a drying device, it is necessary to quickly increase the temperature of the media in order to dry the media effectively. If the temperature setting of the heating unit is high, the temperature of the media will increase quickly. On the other hand, if the temperature setting of the heating unit is too high, the media may be overheated, which may cause the media to deteriorate. [Means for solving the problem]

[0005] A drying device that solves the above problem comprises a drying furnace into which the transported medium enters, and a heating section that heats the medium within the drying furnace, wherein the heating section has an upstream heating mechanism, a downstream heating mechanism located downstream of the upstream heating mechanism in the transport direction of the medium, and an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the transport direction, wherein the upstream heating mechanism has an upstream heating element located so as to be at a predetermined distance from the medium, the downstream heating mechanism has a downstream heating element located so as to be at a distance greater than the predetermined distance from the medium, and the intermediate heating mechanism has an intermediate heating element located so as to be at a distance greater than the predetermined distance from the medium, wherein the set temperature of the upstream heating element is higher than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element is higher than the set temperature of the intermediate heating element.

[0006] A printing system that solves the above problem comprises a printing device that prints an image on a medium and a drying device that dries the printed medium, the printing device comprising a housing and a printing unit that prints an image on the medium within the housing, the drying device comprising a drying oven into which the medium transported from the printing device enters and a heating unit that heats the medium within the drying oven, the heating unit comprising an upstream heating mechanism, a downstream heating mechanism located downstream of the upstream heating mechanism in the medium transport direction, and an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the medium transport direction, the upstream heating mechanism having an upstream heating element located so as to be a predetermined distance from the medium, the downstream heating mechanism having a downstream heating element located so as to be a distance greater than the predetermined distance, the intermediate heating mechanism having an intermediate heating element located so as to be a distance greater than the predetermined distance, the set temperature of the upstream heating element being higher than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element being higher than the set temperature of the intermediate heating element. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side view showing an embodiment of a printing system including a drying device. [Figure 2] FIG. 2 is a side view of the heating unit. [Figure 3] FIG. 3 is a cross-sectional view of the heating element. [Figure 4] FIG. 4 is a graph showing the temperature change of the medium. [Figure 5] FIG. 5 is a graph showing the temperature change of the medium when the medium is heated under conditions different from those in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of a printing system including a drying device will be described below with reference to the drawings. <Printing system> As shown in FIG. 1, the printing system 11 includes a printing device 12 and a drying device 13. The printing device 12 is configured to print an image on a medium 99. The printing device 12 is, for example, an inkjet printer that prints images such as text and photographs by ejecting ink, which is an example of a liquid, onto a medium 99 such as paper or fabric. The drying device 13 is configured to dry the printed medium 99. More specifically, the drying device 13 dries the medium 99 by heating it. The printing system 11 prints and dries a long medium 99 that extends from the printing device 12 to the drying device 13. The printing device 12 and the drying device 13 work together by transmitting signals to each other.

[0009] The printing device 12 and the drying device 13 are aligned in a transport direction D1. The transport direction D1 is the direction in which the medium 99 is transported from the printing device 12 to the drying device 13. In one example, the printing device 12 and the drying device 13 are aligned with a gap between them in the transport direction D1. This is because a user may stand between the printing device 12 and the drying device 13.

[0010] The printing system 11 includes an input unit 14. The input unit 14 is an interface for inputting information to the printing system 11. A user operates the printing system 11 by operating the input unit 14. The input unit 14 is, for example, a touch panel. The input unit 14 may include a button, a lever, a switch, etc. The input unit 14 may be attached to the printing device 12 or the drying device 13. The input unit 14 may be provided in the printing device 12 or the drying device 13. The input unit 14 may be provided in each of the printing device 12 and the drying device 13.

[0011] <Printing device> The printing device 12 may include a feeding unit 21. The feeding unit 21 is configured to feed the medium 99. The feeding unit 21 feeds the medium 99 from, for example, a roll. The roll is an article in which the medium 99 is wound up.

[0012] The feeding unit 21 has a feeding case 22. The feeding case 22 houses a first roll R1. The first roll R1 is a roll in which unprinted medium 99 is wound up. The payout unit 21 has a payout section 23. The payout section 23 is housed in a payout case 22. The payout section 23 pays out the medium 99 from the first roll body R1. The payout section 23 has a payout spindle 24. The payout spindle 24 rotatably supports the first roll body R1. The payout spindle 24 may rotate actively, may rotate passively, or may be fixed to the payout case 22. The medium 99 is paid out from the first roll body R1 as the first roll body R1 rotates. In the payout section 23, the first roll body R1 may rotate as the payout spindle 24 rotates, or may rotate as the medium 99 is pulled.

[0013] The printing device 12 includes a printing unit 25. The printing unit 25 is configured to print on a medium 99. The printing unit 25 prints on the medium 99 fed from the feeding unit 21. The printing unit 25 may also print on the medium 99 fed from another device.

[0014] The printing unit 25 has a housing 26. The housing 26 is adjacent to, for example, the feeding case 22. In one example, the housing 26 is aligned with the feeding case 22 in the conveying direction D1. The printing unit 25 has a printing section 27. The printing section 27 is housed in the housing 26. The printing section 27 prints an image on the medium 99 within the housing 26. The printing section 27 prints on the medium 99 by ejecting liquid onto the medium 99. The printing section 27 prints on the medium 99 fed from the feeding section 23. The printing section 27 prints on the medium 99 transported within the housing 26.

[0015] The printing unit 27 has a head 28. The head 28 has a nozzle surface 30 in which one or more nozzles 29 are opened. The head 28 ejects liquid from the nozzles 29 onto a medium 99. The nozzle surface 30 faces the medium 99.

[0016] The printing unit 27 may have a carriage 31. The carriage 31 carries the head 28. The carriage 31 scans across the medium 99. That is, in one example, the head 28 is a serial head that prints across the width of the medium 99 by scanning across the medium 99. The head 28 may also be a line head that can eject liquid across the width of the medium 99 simultaneously.

[0017] The printing unit 25 has a transport unit 32. The transport unit 32 is configured to transport the medium 99. The transport unit 32 transports the medium 99 within the housing 26. In one example, the transport unit 32 transports the medium 99 in a transport direction D1. In one example, the transport unit 32 transports the medium 99 intermittently. This is because, in one example, the head 28 is a serial head. If the head 28 is a line head, the transport unit 32 may transport the medium 99 continuously.

[0018] The transport unit 32 is housed in the housing 26. The transport unit 32 transports the medium 99 fed out from the feeding unit 23. The transport unit 32 may cause the feeding unit 23 to feed out the medium 99 by pulling the medium 99 from the first roll body R1. The transport unit 32 faces the printing unit 27. In one example, the transport unit 32 is located directly below the printing unit 27.

[0019] The transport unit 32 transports the medium 99 at a predetermined transport speed. The transport speed is indicated, for example, by the average speed of the medium 99. The transport speed is set, for example, by the user operating the input unit 14.

[0020] The conveying section 32 has a first pulley 33, a second pulley 34, and a belt 35. The first pulley 33 and the second pulley 34 are aligned, for example, in the conveying direction D1. The belt 35 is wound around the first pulley 33 and the second pulley 34. The belt 35 rotates together with the first pulley 33 and the second pulley 34.

[0021] The belt 35 supports the medium 99. More specifically, the belt 35 is configured to adsorb the medium 99. In one example, the belt 35 adsorbs the medium 99 using an adhesive. The adhesive is applied to the surface of the belt 35. The belt 35 holds the medium 99 by adsorbing it. This stabilizes the position of the medium 99. The belt 35 may adsorb the medium 99 using, for example, static electricity, or may adsorb the medium 99 using negative pressure caused by suction. The belt 35 rotates while adsorbing the medium 99, thereby transporting the medium 99. The transport unit 32 is not limited to transporting the medium 99 using the belt 35, and may transport the medium 99 using, for example, rollers.

[0022] The printing unit 25 may have one or more printing guide rollers. In one example, the printing unit 25 has a first printing guide roller 36 and a second printing guide roller 37. The printing guide rollers are configured to guide the medium 99. The printing guide rollers guide the medium 99 by contacting the medium 99. The printing guide rollers guide the medium 99 from the feeding unit 21 to the printing unit 25, or from the printing device 12 to the drying device 13.

[0023] The print guide rollers may be located inside or outside the housing 26. In one example, the first print guide roller 36 and the second print guide roller 37 are located outside the housing 26. The first print guide roller 36 guides the medium 99, for example, so that the medium 99 is supplied from outside the housing 26 into the housing 26. In one example, the first print guide roller 36 guides the medium 99 fed from the feeding section 23 into the housing 26. The second print guide roller 37 guides the medium 99, for example, so that the medium 99 is discharged from inside the housing 26 to the outside of the housing 26. In more detail, the second print guide roller 37 guides the printed medium 99 out of the housing 26.

[0024] The printing unit 25 has a printing control unit 38. The printing control unit 38 controls the printing unit 25. More specifically, the printing control unit 38 controls the printing unit 27 and the transport unit 32. The printing control unit 38 may control the feeding unit 21 in addition to the printing unit 25. The printing control unit 38 may also control the feeding unit 23, for example.

[0025] The print control unit 38 may be configured with one or more processors that execute various processes according to a computer program. The print control unit 38 may be configured with one or more dedicated hardware circuits, such as application-specific integrated circuits, that execute at least some of the various processes. The print control unit 38 may be configured with a circuit that includes a combination of a processor and a hardware circuit. The processor includes a CPU and memory, such as RAM and ROM. The memory stores program code or instructions that cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available readable medium that can be accessed by a general-purpose or special-purpose computer.

[0026] The print control unit 38 communicates with the drying device 13. The print control unit 38 may send various signals to the drying device 13. The print control unit 38 notifies the drying device 13 of the status of the printing device 12 by sending signals to the drying device 13. The print control unit 38 receives various signals from the drying device 13. The print control unit 38 can grasp the status of the drying device 13 by receiving signals from the drying device 13.

[0027] <Drying equipment> Drying device 13 includes winding unit 41. Winding unit 41 is configured to wind medium 99. Winding unit 41 winds medium 99 to form a roll body.

[0028] The winding unit 41 has a winding case 42. The winding case 42 houses the second roll body R2. The second roll body R2 is a roll body in which printed medium 99 is wound up and stacked.

[0029] The winding unit 41 has a winding section 43. The winding section 43 winds up the medium 99. More specifically, the winding section 43 winds up the dried medium 99. The winding section 43 has a winding shaft 44. The winding shaft 44 is housed in the winding case 42. The winding shaft 44 rotatably supports the second roll body R2. The medium 99 is wound up as the winding shaft 44 rotates. That is, the second roll body R2 rotates as the winding shaft 44 rotates. The medium 99 is transported in the drying device 13 by being wound up by the winding section 43.

[0030] The winding unit 43 is driven to wind the medium 99 at a speed faster than the transport unit 32. That is, the winding unit 43 is driven so that the winding speed is faster than the transport speed. This applies tension to the medium 99 between the transport unit 32 and the winding unit 43. Applying tension to the medium 99 stabilizes the position of the medium 99. For example, applying tension to the medium 99 makes it easier to peel the medium 99 from the belt 35.

[0031] The winding unit 43 may have a dancer roller 45. The dancer roller 45 may be located inside the winding case 42 or outside the winding case 42. The medium 99 is wound around the dancer roller 45. More specifically, the medium 99 before being wound around the winding shaft 44 is wound around the dancer roller 45. The dancer roller 45 is configured to be displaceable. By displacing, the dancer roller 45 adjusts the tension applied to the medium 99. This allows the winding shaft 44 to stably wind the medium 99 more easily.

[0032] The drying device 13 includes a drying unit 46. The drying unit 46 is configured to dry the medium 99. The drying unit 46 dries the medium 99 that has been printed by the printing device 12. After being dried by the drying unit 46, the medium 99 is taken up by the take-up unit 41.

[0033] The drying unit 46 has a drying oven 47. The drying oven 47 is adjacent to the winding case 42. In one example, the drying oven 47 is aligned with the winding case 42 in the conveying direction D1. A printed medium 99 enters the drying oven 47. The medium 99 transported from the printing device 12 enters the drying oven 47. In the drying oven 47, the medium 99 is transported by the transport section 32 and the winding section 43.

[0034] The drying unit 46 has a heating section 48. The heating section 48 is housed in a drying oven 47. The heating section 48 heats the medium 99 in the drying oven 47. This causes the liquid adhering to the medium 99 to evaporate. As a result, the color components are fixed to the medium 99. The heating section 48 will be described in detail later.

[0035] The drying unit 46 may have an exhaust duct 49. The exhaust duct 49 is a duct for exhausting air from the drying oven 47. The exhaust duct 49 extends from the drying oven 47. The exhaust duct 49 is attached to the drying oven 47. In one example, the exhaust duct 49 is attached to the upper surface of the drying oven 47. This makes it easier to exhaust steam from within the drying oven 47. This is because the steam tends to float upward due to being heated by the heating section 48. Exhausting steam from the drying oven 47 promotes drying of the medium 99.

[0036] The drying unit 46 may include an exhaust fan 50. The exhaust fan 50 is a fan that exhausts air from the drying oven 47. The exhaust fan 50 exhausts air from the drying oven 47 through an exhaust duct 49. The exhaust fan 50 is attached to the drying oven 47. In one example, the exhaust fan 50 is attached to the upper surface of the drying oven 47. The exhaust fan 50 is attached to the exhaust duct 49. The exhaust fan 50 may be located outside the exhaust duct 49 or inside the exhaust duct 49.

[0037] The drying unit 46 may have one or more drying guide rollers. In one example, the drying unit 46 has a first drying guide roller 51 and a second drying guide roller 52. The drying guide rollers are configured to guide the medium 99, similar to the printing guide rollers. The drying guide rollers guide the medium 99 by contacting the medium 99. The drying guide rollers guide the medium 99 from the printing device 12 to the drying device 13, or from the drying unit 46 to the winding unit 41.

[0038] The drying guide rollers may be located inside or outside the drying oven 47. In one example, the first drying guide roller 51 and the second drying guide roller 52 are located outside the drying oven 47. The first drying guide roller 51 guides the medium 99, for example, so that the medium 99 is supplied from outside the drying oven 47 into the drying oven 47. In one example, the first drying guide roller 51 guides the medium 99 transported from the printing device 12 into the drying oven 47. The second drying guide roller 52 guides the medium 99, for example, so that the medium 99 is discharged from inside the drying oven 47 to outside the drying oven 47. More specifically, the second drying guide roller 52 guides the dried medium 99 out of the drying oven 47.

[0039] The drying unit 46 has a drying control unit 53. The drying control unit 53 controls the drying unit 46. More specifically, the drying control unit 53 controls the heating unit 48 and the exhaust fan 50. The drying control unit 53 may control the winding unit 41 in addition to the drying unit 46. The drying control unit 53 may control, for example, the winding unit 43. Like the print control unit 38, the drying control unit 53 may be configured with a processor, may be configured with a hardware circuit, or may be configured with a circuit including a combination thereof.

[0040] The drying control unit 53 may communicate with the printing device 12. More specifically, the drying control unit 53 communicates with the printing control unit 38. The drying control unit 53 sends various signals to the printing control unit 38. The drying control unit 53 notifies the printing control unit 38 of the status of the drying device 13 by sending signals to the printing control unit 38. The drying control unit 53 receives various signals from the printing control unit 38. The drying control unit 53 can grasp the status of the printing device 12 by receiving signals from the printing control unit 38.

[0041] Next, the heating unit 48 will be described. The heating unit 48 heats the medium 99 so as to maintain the medium 99 at a high temperature in order to dry the medium 99. The heating unit 48 heats the medium 99 so as to quickly increase the temperature of the medium 99. By quickly increasing the temperature of the medium 99, it is possible to prevent the drying oven 47 from becoming larger and the drying efficiency from decreasing. To slowly increase the temperature of the medium 99, it would be necessary to increase the size of the drying oven 47 or reduce the conveying speed.

[0042] The heating unit 48 heats the medium 99 to a high temperature to quickly raise the temperature of the medium 99. However, if the temperature of the medium 99 is raised too quickly, the medium 99 may be overheated. In this case, the medium 99 may be deteriorated. Therefore, the heating unit 48 heats the medium 99 so that the medium 99 is maintained at a high temperature while suppressing deterioration of the medium 99. In one example, the heating unit 48 heats the medium 99 so that the medium 99 is maintained at a temperature of 150°C or higher to dry the medium 99 printed with pigment-based ink. If the medium 99 is a blend fabric of 65% polyester and 35% cotton, the medium 99 may deteriorate if it exceeds 170°C. For example, if the medium 99 exceeds 170°C, the medium 99 may yellow. The heating unit 48 heats the medium 99 so that the medium 99 is maintained at a temperature of 150°C or higher and 170°C or lower.

[0043] 2, the heating section 48 has a plurality of heating mechanisms: one upstream heating mechanism 55, one downstream heating mechanism 56, and one intermediate heating mechanism 57. The multiple heating mechanisms are aligned in the conveying direction D1. Specifically, they are aligned in the conveying direction D1 in the order of the upstream heating mechanism 55, the intermediate heating mechanism 57, and the downstream heating mechanism 56. Therefore, the downstream heating mechanism 56 is positioned downstream of the upstream heating mechanism 55 in the conveying direction D1. The intermediate heating mechanism 57 is positioned between the upstream heating mechanism 55 and the downstream heating mechanism 56 in the conveying direction D1.

[0044] The heating mechanism includes one or more heating elements. The heating elements are configured to heat the medium 99. The upstream heating mechanism 55 includes two upstream heating elements. The downstream heating mechanism 56 includes one downstream heating element. The intermediate heating mechanism 57 includes four intermediate heating elements. In one example, the upstream heating mechanism 55 includes a first upstream heating element 60 and a second upstream heating element 61. The downstream heating mechanism 56 includes a first downstream heating element 62. The intermediate heating mechanism 57 includes a first intermediate heating element 63, a second intermediate heating element 64, a third intermediate heating element 65, and a fourth intermediate heating element 66.

[0045] The upstream heating mechanism 55 has an upstream heating member positioned at a predetermined distance from the medium 99. In one example, the upstream heating mechanism 55 has a first upstream heating member 60 positioned at a first distance L1 perpendicular to the medium 99. The upstream heating mechanism 55 can also be said to have the first upstream heating member 60 positioned at a first distance L1 perpendicular to the drying guide roller. The upstream heating mechanism 55 has a second upstream heating member 61 positioned at a second distance L2 perpendicular to the medium 99. The upstream heating mechanism 55 can also be said to have the second upstream heating member 61 positioned at a second distance L2 perpendicular to the drying guide roller. The second upstream heating member 61 may be positioned at a first distance L1 perpendicular to the medium 99. The second distance L2 is greater than the first distance L1. In one example, the first distance L1 is 58 mm. The second distance L2 is 68 mm.

[0046] The shorter the distance between the heating member and the medium 99, the easier it is for the heating member to heat the medium 99. In other words, the shorter the distance between the heating member and the medium 99, the easier it is for the temperature of the medium 99 to rise. Therefore, the first upstream heating member 60 heats the medium 99 more easily than the second upstream heating member 61.

[0047] The downstream heating mechanism 56 has a downstream heating member positioned such that the distance from the medium 99 is greater than a predetermined distance. In one example, the downstream heating mechanism 56 has a first downstream heating member 62 positioned such that the vertical distance from the medium 99 is a second distance L2. The distance between the first downstream heating member 62 and the medium 99 only needs to be greater than the first distance L1. Therefore, the first upstream heating member 60 is more likely to heat the medium 99 than the downstream heating member.

[0048] The intermediate heating mechanism 57 has an intermediate heating member positioned so that the distance from the medium 99 is greater than a predetermined distance. In one example, the intermediate heating mechanism 57 has a first intermediate heating member 63 positioned so that the vertical distance from the medium 99 is a second distance L2. The intermediate heating mechanism 57 has a second intermediate heating member 64 positioned so that the vertical distance from the medium 99 is the second distance L2. The intermediate heating mechanism 57 has a third intermediate heating member 65 positioned so that the vertical distance from the medium 99 is the second distance L2. The intermediate heating mechanism 57 has a fourth intermediate heating member 66 positioned so that the vertical distance from the medium 99 is the second distance L2. The distance between the first intermediate heating member 63 and the medium 99, the distance between the second intermediate heating member 64 and the medium 99, the distance between the third intermediate heating member 65 and the medium 99, and the distance between the fourth intermediate heating member 66 and the medium 99 may be different from each other as long as they are greater than the first distance L1. Therefore, the first upstream heating member 60 heats the medium 99 more easily than the intermediate heating member.

[0049] The multiple heating elements are aligned in the conveying direction D1. In one example, the multiple heating elements are aligned at equal intervals in the conveying direction D1. For example, the multiple heating elements are aligned at 140 mm intervals. The first upstream heating element 60, the second upstream heating element 61, the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, the fourth intermediate heating element 66, and the first downstream heating element 62 are aligned in this order in the conveying direction D1. The first upstream heating element 60 is positioned most upstream of the multiple heating elements. The first downstream heating element 62 is positioned most downstream of the multiple heating elements. Of the multiple heating elements, the heating element positioned most upstream in the conveying direction D1 is positioned closest to the medium 99. This allows the heating unit 48 to quickly raise the temperature of the portion of the medium 99 that has just entered the drying furnace 47. Of the multiple heating elements, heating elements other than the heating element positioned most upstream in the conveying direction D1 are positioned relatively far from the medium 99. This reduces the risk of the heating unit 48 overheating the medium 99.

[0050] The heating elements are infrared heaters. Each of the multiple heating elements has the same configuration. Therefore, the first upstream heating element 60, the second upstream heating element 61, the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, the fourth intermediate heating element 66, and the first downstream heating element 62 are each infrared heaters. The heating elements heat the medium 99 by irradiating it with infrared rays. The heating elements are positioned to face the printed surface of the medium 99. In one example, the heating elements are positioned to face the top surface of the medium 99. The heating elements irradiate the printed surface of the medium 99 with infrared rays. The heating elements are not limited to infrared heaters and may be, for example, a blower that blows hot air onto the medium 99.

[0051] The heating element is driven to heat the medium 99 to a predetermined set temperature. The set temperature is a target temperature of the heating element. For example, if the set temperature is 400 degrees, the heating element is driven to heat the medium 99 to 400 degrees.

[0052] The upstream heating member is driven to heat the medium 99 at a higher temperature than the intermediate heating member. The set temperature of the upstream heating member is higher than the set temperature of the intermediate heating member. In one example, the set temperature of the first upstream heating member 60 is higher than the set temperature of the first intermediate heating member 63, the set temperature of the second intermediate heating member 64, the set temperature of the third intermediate heating member 65, and the set temperature of the fourth intermediate heating member 66. The set temperature of the second upstream heating member 61 is higher than the set temperature of the first intermediate heating member 63, the set temperature of the second intermediate heating member 64, the set temperature of the third intermediate heating member 65, and the set temperature of the fourth intermediate heating member 66.

[0053] The higher the set temperature of the heating element, the easier it is to heat the medium 99. In other words, the higher the set temperature of the heating element, the easier it is for the temperature of the medium 99 to rise. Therefore, the upstream heating element heats the medium 99 more easily than the intermediate heating element. This allows the heating unit 48 to quickly raise the temperature of the portion of the medium 99 that has just entered the drying furnace 47. Furthermore, because the set temperature of the intermediate heating element is lower than the set temperature of the upstream heating element, the risk of the medium 99 being overheated is reduced.

[0054] The downstream heating element is driven to heat the medium 99 to a higher temperature than the intermediate heating element. The set temperature of the downstream heating element is higher than the set temperature of the intermediate heating element. In one example, the set temperature of the first downstream heating element 62 is higher than the set temperature of the first intermediate heating element 63, the set temperature of the second intermediate heating element 64, the set temperature of the third intermediate heating element 65, and the set temperature of the fourth intermediate heating element 66.

[0055] The portion of the medium 99 heated by the downstream heating member is easily cooled by the outside air. In this regard, the set temperature of the downstream heating member is higher than the set temperature of the intermediate heating member, thereby reducing the risk of the temperature of the medium 99 dropping.

[0056] The upstream heating element is driven to heat the medium 99 to a higher temperature than the downstream heating element. The set temperature of the upstream heating element is higher than the set temperature of the downstream heating element. In one example, the set temperature of the first upstream heating element 60 is higher than the set temperature of the first downstream heating element 62. The set temperature of the second upstream heating element 61 is higher than the set temperature of the first downstream heating element 62. This allows the heating unit 48 to quickly raise the temperature of the portion of the medium 99 that has just entered the drying furnace 47.

[0057] The capacity of the intermediate heating member may be smaller than the capacity of the upstream heating member and the capacity of the downstream heating member. In one example, the capacity of the first intermediate heating member 63, the capacity of the second intermediate heating member 64, the capacity of the third intermediate heating member 65, and the capacity of the fourth intermediate heating member 66 are smaller than the capacity of the first upstream heating member 60 and the capacity of the second upstream heating member 61. The capacity of the first intermediate heating member 63, the capacity of the second intermediate heating member 64, the capacity of the third intermediate heating member 65, and the capacity of the fourth intermediate heating member 66 are smaller than the capacity of the first downstream heating member 62. Because the set temperatures of the intermediate heating members are relatively small, heating members with small capacities can be used as the intermediate heating members. This reduces the power consumption of the heating unit 48. The capacity of some of the multiple intermediate heating members may be smaller than the capacity of the upstream heating member and the downstream heating member.

[0058] The set temperatures are set by the drying control unit 53. The set temperature of the upstream heating member is set by the drying control unit 53 to be higher than the set temperature of the intermediate heating member. The set temperature of the downstream heating member is set by the drying control unit 53 to be higher than the set temperature of the intermediate heating member. The set temperature of the upstream heating member is set by the drying control unit 53 to be higher than the set temperature of the downstream heating member.

[0059] The set temperature may be set for each heating mechanism. The set temperature may be set for each heating element. In one example, the set temperature is set for each of the upstream heating mechanism 55, the intermediate heating mechanism 57, and the downstream heating mechanism 56. Therefore, the set temperature of the first upstream heating element 60 and the set temperature of the second upstream heating element 61 are the same. The set temperature of the first intermediate heating element 63, the set temperature of the second intermediate heating element 64, the set temperature of the third intermediate heating element 65, and the set temperature of the fourth intermediate heating element 66 are the same.

[0060] The heating element extends in a width direction D2. The width direction D2 is a direction different from the conveying direction D1. The width direction D2 is a direction that indicates the width of the medium 99. By extending in the width direction D2, the heating element irradiates infrared rays across the width of the medium 99.

[0061] As shown in Fig. 3, the heating element is configured to be larger than the overall width of the medium 99 in the width direction D2. Specifically, the heating element is configured to be longer than the maximum width of the medium 99 that the drying device 13 can accommodate. While Fig. 3 illustrates the first upstream heating element 60, the other heating elements are also configured to be longer than the maximum width of the medium 99. In one example, when the medium 99 is viewed from above, the heating element is so long that both ends thereof protrude by 100 mm or more.

[0062] The heating element radiates infrared rays radially. For example, the heating element radiates infrared rays as shown by the black arrows in FIG. 3. Therefore, in the width direction D2, portions of the medium 99 located at the edges tend to receive less heat from the heating element than portions of the medium 99 located at the center. In this regard, by having a long heating element in the width direction D2, the gradient in the amount of heat received by the medium 99 is reduced.

[0063] The heating element has one central portion 70 and two end portions 71. The central portion 70 is a portion of the heating element that is located in the center in the width direction D2. The end portions 71 are portions of the heating element that are located at the ends in the width direction D2. The two end portions 71 are located on either side of the central portion 70 in the width direction D2. In one example, the two end portions 71 are portions that are 400 mm from each end of the heating element.

[0064] The heating element is configured so that the temperature of the end portion 71 is higher than the temperature of the central portion 70. More specifically, the heating element is configured so that the amount of infrared rays generated from the end portion 71 is higher than the amount of infrared rays generated from the central portion 70. For example, the heating element is configured so that the output of the end portion 71 is 120% or more of the output of the central portion 70. This reduces the gradient in the amount of heat received by the medium 99. The heating element may be driven so that the temperature of the central portion 70 becomes a set temperature, or may be driven so that the temperature of the end portion 71 becomes a set temperature.

[0065] The heating element has a heating wire 72. The heating wire 72 generates heat when an electric current flows through it. The heating wire 72 is, for example, a wound wire. The heating wire 72 extends in the width direction D2. The heating wire 72 is configured so that the density of the end portions in the width direction D2 is greater than the density of the central portion. In one example, the heating wire 72 is configured so that the number of turns per unit length in the portion corresponding to the central portion 70 is greater than the number of turns per unit length in the portion corresponding to the end portion 71. More specifically, the heating wire 72 has one first-density portion 73 and two second-density portions 74. The first-density portion 73 is located in the center in the width direction D2. The first-density portion 73 corresponds to the central portion 70 of the heating wire 72. The second-density portion 74 is located at the end in the width direction D2. The second-density portion 74 corresponds to the end portion 71 of the heating wire 72. The density of the second density portion 74 is greater than the density of the first density portion 73. The heating wire 72 causes the temperature of the end portion 71 to be higher than that of the central portion 70 of the heating element.

[0066] The heating element has a tubular member 75. The tubular member 75 houses a heating wire 72. The tubular member 75 is configured to emit infrared rays when heated by the heating wire 72. The tubular member 75 is made of, for example, ceramic. The tubular member 75 extends in the width direction D2. When viewed from the width direction D2, the tubular member 75 has a triangular shape. In this case, the rigidity of the tubular member 75 is greater than when it is cylindrical. In other words, the heating element is less likely to bend in the width direction D2.

[0067] Because the cylindrical member 75 is a triangular cylinder, it has three peripheral surfaces. The three peripheral surfaces include a bottom surface 76. That is, the cylindrical member 75 has the bottom surface 76. The cylindrical member 75 is positioned so that the bottom surface 76 faces the medium 99. More specifically, the cylindrical member 75 is positioned so that the bottom surface 76 faces downward. This makes it easier for infrared rays to be irradiated onto the medium 99 compared to when the corners of the cylindrical member 75 face the medium 99.

[0068] As shown in FIG. 2, the first upstream heating member 60 may be positioned so that its bottom surface 76 faces downstream in the conveyance direction D1. The first upstream heating member 60 may be positioned so that a perpendicular line S1 extending from its bottom surface 76 faces downstream in the conveyance direction D1. In this case, the first upstream heating member 60 irradiates infrared rays into the radiation area irradiated by the second upstream heating member 61. That is, the radiation area of ​​the first upstream heating member 60 overlaps with the radiation area of ​​the second upstream heating member 61. This allows the temperature of the medium 99 entering the drying furnace 47 to rise quickly. In one example, the first upstream heating member 60 is positioned so that the perpendicular line S1 is inclined 1 to 10 degrees relative to the perpendicular direction of the medium 99. Preferably, the first upstream heating member 60 is positioned so that the perpendicular line S1 is inclined 6 degrees relative to the perpendicular direction of the medium 99. The bottom surface 76 of the first upstream heating member 60 faces downstream in the conveyance direction D1 while facing the medium 99. The heating members other than the first upstream heating member 60 are positioned so that the perpendicular line S1 extends perpendicular to the medium 99. In other words, the heating members other than the first upstream heating member 60 are positioned so that their bottom surfaces 76 are parallel to the medium 99.

[0069] The heating mechanism has one or more reflectors. In one example, the heating mechanism has the same number of reflectors as the heating elements. The upstream heating mechanism 55 has two upstream reflectors. The downstream heating mechanism 56 has one downstream reflector. The intermediate heating mechanism 57 has four intermediate reflectors. Specifically, the upstream heating mechanism 55 has a first upstream reflector 77 and a second upstream reflector 78. The downstream heating mechanism 56 has a first downstream reflector 79. The intermediate heating mechanism 57 has a first intermediate reflector 80, a second intermediate reflector 81, a third intermediate reflector 82, and a fourth intermediate reflector 83.

[0070] The reflectors are positioned to reflect infrared rays generated from the heating members toward the medium 99. The upstream reflector reflects infrared rays generated from the upstream heating member toward the medium 99. The downstream reflector reflects infrared rays generated from the downstream heating member toward the medium 99. The intermediate reflector reflects infrared rays generated from the intermediate heating member toward the medium 99. Specifically, the first upstream reflector 77 reflects infrared rays generated from the first upstream heating member 60 toward the medium 99. The second upstream reflector 78 reflects infrared rays generated from the second upstream heating member 61 toward the medium 99. The first downstream reflector 79 reflects infrared rays generated from the first downstream heating member 62 toward the medium 99. The first intermediate reflector 80 reflects infrared rays generated from the first intermediate heating member 63 toward the medium 99. The second intermediate reflector 81 reflects infrared rays generated from the second intermediate heating member 64 toward the medium 99. The third intermediate reflector 82 reflects infrared rays generated from the third intermediate heating member 65 toward the medium 99. The fourth intermediate reflector 83 reflects the infrared rays generated from the fourth intermediate heating member 66 toward the medium 99 .

[0071] The first upstream reflector 77 may be positioned to reflect infrared rays generated from the first upstream heating member 60 downstream in the transport direction D1. The first upstream reflector 77 may be positioned so that its optical axis G1 faces downstream in the transport direction D1. In this case, the first upstream reflector 77 reflects infrared rays generated from the first upstream heating member 60 toward the radiation area where the second upstream heating member 61 irradiates infrared rays. That is, the radiation area of ​​the first upstream heating member 60 and the radiation area of ​​the second upstream heating member 61 overlap. This allows the temperature of the medium 99 entering the drying furnace 47 to rise quickly. In one example, the first upstream reflector 77 is positioned so that the optical axis G1 is inclined 1 to 10 degrees relative to the perpendicular direction of the medium 99. Preferably, the first upstream reflector 77 is positioned so that the optical axis G1 is inclined 6 degrees relative to the perpendicular direction of the medium 99. The first upstream reflector 77 is positioned so that the optical axis G1 overlaps with the perpendicular line S1 of the first upstream heating member 60. The reflectors other than the first upstream reflector 77 are positioned so that their optical axes G1 are perpendicular to the medium 99. The reflectors other than the first upstream reflector 77 are positioned so that their optical axes G1 overlap with the perpendicular line S1. The overlap of the optical axes G1 with the perpendicular line S1 improves the efficiency with which the reflectors reflect infrared rays.

[0072] The heating mechanisms each have a controller. Specifically, the upstream heating mechanism 55 has an upstream controller 87. The downstream heating mechanism 56 has a downstream controller 88. The intermediate heating mechanism 57 has an intermediate controller 89. The controller may be configured with a processor or a hardware circuit.

[0073] The controller controls the heating element so that the heating element reaches the set temperature. That is, the controller controls the temperature of the heating element. In one example, the controller controls the temperature of the heating element by controlling the current duty of the heating element.

[0074] The upstream controller 87 controls the temperature of the upstream heating member. More specifically, the upstream controller 87 uniformly controls the temperature of the first upstream heating member 60 and the temperature of the second upstream heating member 61. The upstream controller 87 controls the first upstream heating member 60 and the second upstream heating member 61 at a common set temperature. The upstream controller 87 controls the first upstream heating member 60 and the second upstream heating member 61 so that the average temperature of the first upstream heating member 60 and the second upstream heating member 61 becomes the set temperature. By having one upstream controller 87 control the first upstream heating member 60 and the second upstream heating member 61, the upstream heating mechanism 55 does not need to have multiple upstream controllers 87. This simplifies the configuration of the upstream heating mechanism 55.

[0075] The downstream controller 88 controls the temperature of the downstream heating element. Specifically, the downstream controller 88 controls the temperature of the first downstream heating element 62. The intermediate controller 89 controls the temperatures of the intermediate heating members. More specifically, the intermediate controller 89 uniformly controls the temperatures of the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66. The intermediate controller 89 controls the temperatures of the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66 at a common set temperature. The intermediate controller 89 controls the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66 so that the average temperature of the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66 becomes the set temperature. By having a single intermediate controller 89 control the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66, the intermediate heating mechanism 57 does not need to have multiple intermediate controllers 89. Therefore, the intermediate heating mechanism 57 has a simple configuration.

[0076] As shown in Fig. 4, the drying device 13 dries the medium 99 by maintaining the medium 99 at a temperature between 150°C and 170°C for a long period of time. The graph shown in Fig. 4 shows the temperature change of the medium 99 over time. The temperature of the medium 99 is measured by a thermocouple attached to the medium 99.

[0077] In the example shown in FIG. 4, the drying device 13 maintains the medium 99 at a temperature between 150°C and 170°C for 81.2 seconds. The set temperatures of the first upstream heating member 60 and the second upstream heating member 61 are, for example, 490°C. The set temperatures of the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66 are, for example, 395°C. The set temperature of the first downstream heating member 62 is, for example, 445°C. The transport speed of the medium 99 is, for example, 10.2 mm / sec. In this example, the color difference ΔE00 between the medium 99 before drying and the medium 99 after drying is 0.72. If the color difference ΔE00 is 2.00 or less, it can be said that the medium 99 has not deteriorated.

[0078] 5, the drying device 13 dries the medium 99 by maintaining the medium 99 at a temperature of 150° C. or higher and 170° C. or lower for a long period of time. The graph shown in FIG. 5, like the graph shown in FIG. 4, shows the temperature change of the medium 99 over time.

[0079] In the example shown in FIG. 5, the drying device 13 maintains the medium 99 at a temperature of 150°C or higher and 170°C or lower for 45.0 seconds. The set temperatures of the first upstream heating member 60 and the second upstream heating member 61 are, for example, 500°C. The set temperatures of the first intermediate heating member 63, the second intermediate heating member 64, the third intermediate heating member 65, and the fourth intermediate heating member 66 are, for example, 370°C. The set temperature of the first downstream heating member 62 is, for example, 455°C. The transport speed of the medium 99 is, for example, 20.0 mm / sec. According to this example, the color difference ΔE00 between the medium 99 before drying and the medium 99 after drying is 0.63.

[0080] <Actions and Effects of the Example> Next, the operation and effects of the above embodiment will be described. (1) The upstream heating mechanism 55 has a first upstream heating member 60 positioned at a predetermined distance from the medium 99. The downstream heating mechanism 56 has a downstream heating member positioned at a distance greater than a predetermined distance from the medium 99. The intermediate heating mechanism 57 has an intermediate heating member positioned at a distance greater than a predetermined distance from the medium 99. The set temperature of the first upstream heating member 60 is higher than the set temperature of the intermediate heating member. The set temperature of the downstream heating member is higher than the set temperature of the intermediate heating member. In the drying device 13, the shorter the distance between the heating member and the medium 99, the more likely the temperature of the medium 99 will rise. In the drying device 13, the higher the set temperature of the heating member, the more likely the temperature of the medium 99 will rise. With the above configuration, the temperature of the medium 99 is quickly raised by the first upstream heating member 60, which is relatively close to the medium 99 and has a relatively high set temperature. The intermediate heating member, which is relatively close to the medium 99 and has a relatively low set temperature, reduces the risk of the temperature of the medium 99 rising excessively. The downstream heating element, which is located at a relatively large distance from the medium 99 and has a relatively high set temperature, reduces the risk of the temperature of the medium 99 dropping. In this way, the drying device 13 can dry the medium 99 effectively.

[0081] (2) The set temperature of the first upstream heating member 60 is higher than the set temperature of the downstream heating member 60. According to the above configuration, the temperature of the medium 99 is quickly increased by the first upstream heating member 60. (3) The first upstream heating member 60, the downstream heating member, and the intermediate heating member are each an infrared heater. With the above configuration, the heating unit 48 can heat the medium 99 more easily than, for example, when the heating unit 48 heats the medium 99 by blowing hot air onto the medium 99.

[0082] (4) The downstream reflector is positioned so that its optical axis G1 is perpendicular to the medium 99. The intermediate reflector is positioned so that its optical axis G1 is perpendicular to the medium 99. The first upstream reflector 77 is positioned so that its optical axis G1 faces downstream in the transport direction D1. With the above configuration, the radiation area of ​​the first upstream heating member 60 overlaps with the radiation area of ​​a heating member positioned downstream of the first upstream heating member 60, for example, the second upstream heating member 61. This allows the temperature of the medium 99 to rise quickly.

[0083] (5) The first upstream heating member 60, the downstream heating member, and the intermediate heating member are each configured so that the temperature of the edge portion 71 is higher than the temperature of the center portion 70 in the width direction D2. Because infrared rays are generated radially from the heating members, the amount of radiation received by the edge portions of the medium 99 tends to be smaller than the amount of radiation received by the center portion of the medium 99. In this regard, with the above configuration, the amount of radiation received by the edge portions of the medium 99 is greater. Therefore, the heating unit 48 can heat the medium 99 evenly.

[0084] (6) When viewed from the width direction D2, each of the first upstream heating member 60, the downstream heating member, and the intermediate heating member has a substantially triangular shape having a bottom surface 76, and is positioned so that the bottom surface 76 faces the medium 99. With the above configuration, the amount of radiation received by the medium 99 is increased.

[0085] (7) The first upstream heating member 60 is positioned so that the bottom surface 76 of the first upstream heating member 60 faces downstream in the transport direction D1. According to the above configuration, the temperature of the medium 99 is quickly increased by the first upstream heating member 60 and a heating member positioned downstream of the first upstream heating member 60, such as the second upstream heating member 61.

[0086] (8) The capacity of the intermediate heating member is smaller than that of the first upstream heating member 60 and smaller than that of the downstream heating member. Because the set temperature of the intermediate heating member is relatively low, the capacity of the intermediate heating member can be made small. Therefore, with the above configuration, the power consumption of the heating unit 48 is reduced.

[0087] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0088] The heating mechanism may have the same number of controllers as the number of heating elements. The multiple heating elements may be driven at individual set temperatures. The unwinding section 23 may have a dancer roller, similar to the winding section 43.

[0089] The liquid ejected by the head 28 is not limited to ink, but may be a liquid in which particles of a functional material are dispersed or mixed in a liquid. For example, the head 28 may eject a liquid containing, in a dispersed or dissolved form, a material such as an electrode material or a pixel material used in the manufacture of liquid crystal displays, electroluminescent displays, and surface-emitting displays.

[0090] The feeding unit 21 has the feeding case 22, but is not limited to this. For example, the first roll body R1 may be disposed in an exposed state. The winding unit 41 has a winding case 42, but is not limited to this. For example, the second roll body R2 may be disposed in an exposed state.

[0091] The cylindrical member 75 of the heating member has a triangular shape with a vertex when viewed from the width direction D2, but is not limited to this and may have a rounded triangular shape without a vertex. In other words, the cylindrical member 75 only needs to have a substantially triangular shape with a bottom surface 76 when viewed from the width direction D2.

[0092] <Technical philosophy> The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below.

[0093] (A) A drying apparatus includes a drying furnace into which a medium being transported enters, and a heating unit that heats the medium within the drying furnace. The heating unit includes an upstream heating mechanism, a downstream heating mechanism located downstream of the upstream heating mechanism in the medium transport direction, and an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the medium transport direction. The upstream heating mechanism has an upstream heating element located at a predetermined distance from the medium, the downstream heating mechanism has a downstream heating element located at a distance greater than the predetermined distance from the medium, and the intermediate heating mechanism has an intermediate heating element located at a distance greater than the predetermined distance from the medium. The set temperature of the upstream heating element is higher than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element is higher than the set temperature of the intermediate heating element. In the drying apparatus, the shorter the distance between the heating element and the medium, the more likely the temperature of the medium will rise. In the drying apparatus, the higher the set temperature of the heating element, the more likely the temperature of the medium will rise. According to the above configuration, the upstream heating element, which is relatively close to the medium and has a relatively high set temperature, quickly raises the temperature of the medium. The intermediate heating element, which is relatively far from the medium and has a relatively low set temperature, reduces the risk of the medium temperature rising excessively. The downstream heating element, which is relatively far from the medium and has a relatively high set temperature, reduces the risk of the medium temperature dropping. In this way, the drying device can effectively dry the medium.

[0094] (B) In the drying device, the set temperature of the upstream heating member may be higher than the set temperature of the downstream heating member. According to the above configuration, the temperature of the medium is quickly increased by the upstream heating member.

[0095] (C) In the drying device, each of the upstream heating element, the downstream heating element, and the intermediate heating element may be an infrared heater. With this configuration, the heating element can heat the medium more easily than when the heating element heats the medium by blowing hot air onto the medium, for example.

[0096] (D) In ​​the drying device described above, the heating section may include an upstream reflector that reflects infrared rays generated by the upstream heating element toward the medium, a downstream reflector that reflects infrared rays generated by the downstream heating element toward the medium, and an intermediate reflector that reflects infrared rays generated by the intermediate heating element toward the medium, wherein the downstream reflector is positioned so that its optical axis is perpendicular to the medium, the intermediate reflector is positioned so that its optical axis is perpendicular to the medium, and the upstream reflector is positioned so that its optical axis faces downstream in the transport direction. According to the above configuration, the radiation area of ​​the upstream heating element overlaps with the radiation area of ​​the heating element positioned downstream of the upstream heating element. This allows the temperature of the medium to rise quickly.

[0097] (E) In the drying device described above, each of the upstream heating element, the downstream heating element, and the intermediate heating element may extend in a width direction different from the conveying direction, and may be configured so that the temperature at the edge portions is higher than the temperature at the center portion in the width direction. Because infrared rays are generated radially from the heating elements, the amount of radiation received by the edge portions of the medium tends to be smaller than the amount of radiation received by the center portion of the medium. In this regard, with the above configuration, the amount of radiation received by the edge portions of the medium is greater. Therefore, the heating unit can heat the medium evenly.

[0098] (F) In the drying device, each of the upstream heating member, the downstream heating member, and the intermediate heating member may extend in a width direction that is different from the conveyance direction, and when viewed from the width direction, may have a substantially triangular shape having a bottom surface, and may be positioned so that the bottom surface faces the medium. With the above configuration, the amount of radiation received by the medium is increased.

[0099] (G) In the drying device, the upstream heating element may be positioned so that the bottom surface of the upstream heating element faces downstream in the transport direction. With this configuration, the temperature of the medium is quickly increased by the upstream heating element and a heating element positioned downstream of the upstream heating element.

[0100] (H) In the drying device described above, the capacity of the intermediate heating element may be smaller than that of the upstream heating element and smaller than that of the downstream heating element. Since the set temperature of the intermediate heating element is relatively low, the capacity of the intermediate heating element can be reduced. Therefore, with the above configuration, the power consumption of the heating unit is reduced.

[0101] (I) A printing system includes a printing device that prints an image on a medium and a drying device that dries the printed medium, the printing device including a housing and a printing unit that prints an image on the medium within the housing, the drying device including a drying oven into which the medium transported from the printing device enters and a heating unit that heats the medium within the drying oven, the heating unit including an upstream heating mechanism, a downstream heating mechanism located downstream of the upstream heating mechanism in a medium transport direction, and an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the medium transport direction, the upstream heating mechanism including an upstream heating element located at a predetermined distance from the medium, the downstream heating mechanism including a downstream heating element located at a distance greater than the predetermined distance from the medium, the intermediate heating mechanism including an intermediate heating element located at a distance greater than the predetermined distance from the medium, the upstream heating element having a set temperature higher than the set temperature of the intermediate heating element, and the downstream heating element having a set temperature higher than the set temperature of the intermediate heating element. With the above configuration, the same effect as the drying device described above can be achieved. [Explanation of symbols]

[0102] 11...printing system, 12...printing device, 13...drying device, 14...input section, 21...feeding unit, 22...feeding case, 23...feeding section, 24...feeding shaft, 25...printing unit, 26...casing, 27...printing section, 28...head, 29...nozzle, 30...nozzle surface, 31...carriage, 32...conveying section, 33...first pulley, 34...second pulley, 35...belt, 36...first printing guide roller, 37...second printing guide roller, 38...printing control section, 41...winding unit, 42...winding case, 43...winding section, 44...winding shaft, 45...dancer roller, 46...drying unit, 47...drying oven, 48...heating section, 49...exhaust duct, 50...exhaust fan, 51...first drying guide roller, 52...second drying guide roller, 53...drying control section, 55...upstream heating mechanism, 5 6...downstream heating mechanism, 57...intermediate heating mechanism, 60...first upstream heating element, 61...second upstream heating element, 62...first downstream heating element, 63...first intermediate heating element, 64...second intermediate heating element, 65...third intermediate heating element, 66...fourth intermediate heating element, 70...center portion, 71...end portion, 72...heating wire, 73...first density portion, 74...second density portion, 75...tubular element, 76...bottom surface, 77...first upstream Reflector, 78...second upstream reflector, 79...first downstream reflector, 80...first intermediate reflector, 81...second intermediate reflector, 82...third intermediate reflector, 83...fourth intermediate reflector, 87...upstream controller, 88...downstream controller, 89...intermediate controller, 99...medium, D1...conveyance direction, D2...width direction, G1...optical axis, L1...first distance, L2...second distance, R1...first roll body, R2...second roll body, S1...vertical line.

Claims

1. a drying oven into which the medium to be conveyed enters; a heating unit that heats the medium in the drying furnace, The heating unit is an upstream heating mechanism; a downstream heating mechanism located downstream of the upstream heating mechanism in a medium transport direction; an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the conveying direction, the upstream heating mechanism has an upstream heating member positioned at a predetermined distance from the medium; the downstream heating mechanism has a downstream heating member positioned so that the distance from the medium is greater than the predetermined distance; the intermediate heating mechanism has an intermediate heating member positioned so that the distance between the intermediate heating member and the medium is greater than the predetermined distance; the set temperature of the upstream heating member is higher than the set temperature of the intermediate heating member; A drying device, characterized in that the set temperature of the downstream heating member is higher than the set temperature of the intermediate heating member.

2. 2. The drying device according to claim 1, wherein the set temperature of the upstream heating member is higher than the set temperature of the downstream heating member.

3. 3. The drying device according to claim 1, wherein each of the upstream heating member, the downstream heating member, and the intermediate heating member is an infrared heater.

4. The heating unit is an upstream reflector that reflects infrared rays generated from the upstream heating member toward the medium; a downstream reflector that reflects infrared rays generated from the downstream heating member toward the medium; an intermediate reflector that reflects infrared rays generated from the intermediate heating member toward the medium; the downstream reflector is positioned so that the optical axis of the downstream reflector is perpendicular to the medium; the intermediate reflector is positioned so that the optical axis of the intermediate reflector is perpendicular to the medium; 4. The drying device according to claim 3, wherein the upstream reflector is positioned so that the optical axis of the upstream reflector faces downstream in the conveying direction.

5. Each of the upstream heating member, the downstream heating member, and the intermediate heating member is extending in a width direction which is a direction different from the conveying direction, 4. The drying device according to claim 3, wherein the temperature at the end portions in the width direction is higher than the temperature at the central portion.

6. Each of the upstream heating member, the downstream heating member, and the intermediate heating member is extending in a width direction which is a direction different from the conveying direction, When viewed from the width direction, the shape is substantially triangular having a bottom surface, 4. The drying device according to claim 3, wherein the bottom surface is positioned so as to face the medium.

7. The drying device according to claim 6 , wherein the upstream heating member is positioned so that the bottom surface of the upstream heating member faces downstream in the conveying direction.

8. 4. The drying apparatus according to claim 3, wherein the capacity of the intermediate heating member is smaller than the capacity of the upstream heating member and smaller than the capacity of the downstream heating member.

9. a printing device for printing an image on a medium; a drying device that dries the printed medium, The printing device The housing and a printing unit that prints an image on a medium within the housing, The drying device is a drying oven into which the medium conveyed from the printing device enters; a heating unit that heats the medium in the drying furnace, The heating unit is an upstream heating mechanism; a downstream heating mechanism located downstream of the upstream heating mechanism in a medium transport direction; an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the conveying direction, the upstream heating mechanism has an upstream heating member positioned at a predetermined distance from the medium; the downstream heating mechanism has a downstream heating member positioned so that the distance from the medium is greater than the predetermined distance; the intermediate heating mechanism has an intermediate heating member positioned so that the distance between the intermediate heating member and the medium is greater than the predetermined distance; the set temperature of the upstream heating member is higher than the set temperature of the intermediate heating member; A printing system, wherein the set temperature of the downstream heating element is higher than the set temperature of the intermediate heating element.

Images