Drying device and printing system

Abstract

The invention provides a drying device capable of effectively drying a medium and a printing system. A drying device is provided with: a drying furnace into which a conveyed medium enters; the heating part is used for heating the medium in the drying furnace, and the heating part is provided with an upstream heating mechanism; a downstream heating mechanism located downstream of the upstream heating mechanism in the conveying direction of the medium; and an intermediate heating mechanism located between the upstream heating mechanism and the downstream heating mechanism in the conveyance direction, the upstream heating mechanism having an upstream heating member located at a position at a predetermined distance from the medium, and the downstream heating mechanism having a downstream heating member located at a position at a distance greater than the predetermined distance from the medium, the intermediate heating mechanism has an intermediate heating member located at a position at a distance greater than a predetermined distance from the medium, the set temperature of the upstream heating member being greater than the set temperature of the intermediate heating member, and the set temperature of the downstream heating member being greater than the set temperature of the intermediate heating member.

Description

Technical Field

[0001] This invention relates to a drying apparatus and a printing system. Background Technology

[0002] Patent Document 1 describes a drying apparatus that heats a medium using a heating element. The drying apparatus dries the medium by heating it.

[0003] In such a drying apparatus, a rapid temperature rise of the medium is required for effective drying. If the set temperature of the heating element is too high, the medium temperature will rise rapidly. On the other hand, if the set temperature of the heating element is too high, the medium may be overheated. In this case, the medium may deteriorate.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-2473 Summary of the Invention

[0005] A drying apparatus for solving the above-mentioned problems includes: a drying oven into which a conveyed medium enters; 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 conveying direction of the medium; and an intermediate heating mechanism located between the upstream and downstream heating mechanisms in the conveying direction, wherein 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, wherein the set temperature of the upstream heating element is greater than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element.

[0006] A printing system for solving the above-mentioned problems includes: a printing apparatus for printing an image on a medium; and a drying apparatus for drying the printed medium. The printing apparatus includes: a housing; a printing section for printing an image on the medium within the housing; and the drying apparatus includes: a drying oven into which a medium conveyed from the printing apparatus enters; and a heating section for heating the medium within the drying oven. The heating section includes: an upstream heating mechanism; a downstream heating mechanism located downstream of the upstream heating mechanism in the medium conveying direction; and an intermediate heating mechanism located between the upstream and downstream heating mechanisms in the conveying 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 greater than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element. Attached Figure Description

[0007] Figure 1 This is a side view illustrating one embodiment of a printing system equipped with a drying device.

[0008] Figure 2 This is a side view of the heating element.

[0009] Figure 3 This is a cross-sectional view of the heating component.

[0010] Figure 4 A graph representing the temperature change of the medium.

[0011] Figure 5 To indicate in relation to Figure 4 A graph showing the temperature change of the medium when it is heated under different conditions. Detailed Implementation

[0012] Hereinafter, an embodiment of a printing system equipped with a drying device will be described with reference to the accompanying drawings.

[0013] Printing System

[0014] like Figure 1As shown, the printing system 11 includes a printing device 12 and a drying device 13. The printing device 12 is configured to print images on a medium 99. The printing device 12 is, for example, an inkjet printer that prints text, photographs, and other images by spraying ink, which is an example of a liquid, onto the medium 99, such as paper or cloth. The drying device 13 is configured to dry the medium 99 to be printed. Specifically, the drying device 13 dries the medium 99 by heating it. The printing system 11 performs printing and drying on a strip of medium 99 extending from the printing device 12 to the drying device 13. The printing device 12 and the drying device 13 cooperate by sending signals to each other.

[0015] The printing unit 12 and the drying unit 13 are arranged in the transport direction D1. The transport direction D1 is the direction in which the medium 99 is transported from the printing unit 12 to the drying unit 13. In one example, the printing unit 12 and the drying unit 13 are arranged with a gap between them in the transport direction D1. This is because a user may sometimes enter between the printing unit 12 and the drying unit 13.

[0016] The printing system 11 includes an input unit 14. The input unit 14 is an interface for inputting information into the printing system 11. Users operate the printing system 11 by operating the input unit 14. The input unit 14 may be, for example, a touch panel. The input unit 14 may also include buttons, levers, switches, etc. The input unit 14 can be mounted on either the printing apparatus 12 or the drying apparatus 13. Alternatively, the input unit 14 may be mounted on both the printing apparatus 12 and the drying apparatus 13.

[0017] Printing apparatus

[0018] The printing apparatus 12 may also include an unwinding unit 21. The unwinding unit 21 is configured to unwind the medium 99. For example, the unwinding unit 21 unwinds the medium 99 from a roll. The roll is an article formed by winding and overlapping the medium 99.

[0019] The unwinding unit 21 has an unwinding housing 22. The unwinding housing 22 houses a first roll R1. The first roll R1 is a roll formed by winding and overlapping media 99 before printing. The unwinding unit 21 has an unwinding section 23. The unwinding section 23 is housed in the unwinding housing 22. The unwinding section 23 unwinds the media 99 from the first roll R1. The unwinding section 23 has an unwinding shaft 24. The unwinding shaft 24 rotatably supports the first roll R1. The unwinding shaft 24 can rotate actively, rotate passively, or be fixed to the unwinding housing 22. By rotating the first roll R1, the media 99 is unwound from the first roll R1. In the unwinding section 23, the first roll R1 can rotate either by rotating the unwinding shaft 24 or by being pulled by the media 99.

[0020] The printing apparatus 12 includes a printing unit 25. The printing unit 25 is configured to perform printing on a medium 99. The printing unit 25 performs printing on the medium 99 that is unwound from the unwinding unit 21. The printing unit 25 may also perform printing on the medium 99 that is unwound from another device.

[0021] The printing unit 25 has a housing 26. The housing 26 is adjacent to, for example, the unwinding housing 22. In one example, the housing 26 and the unwinding housing 22 are arranged in the transport direction D1.

[0022] The printing unit 25 has a printing section 27. The printing section 27 is housed in a housing 26. The printing section 27 prints images on a medium 99 inside the housing 26. The printing section 27 prints on the medium 99 by spraying liquid onto the medium 99. The printing section 27 prints on the medium 99 that is unwound from the unwinding section 23. The printing section 27 prints on the medium 99 that is transported inside the housing 26.

[0023] The printing section 27 has a head 28. The head 28 has a nozzle face 30 with one or more nozzles 29 opening. The head 28 sprays liquid from the nozzles 29 onto the medium 99. The nozzle face 30 is opposite to the medium 99.

[0024] The printing unit 27 may also have a carriage 31. The carriage 31 carries the head 28. The carriage 31 scans relative to 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 relative to the medium 99. The head 28 may also be a line head that can spray liquid all at once across the width of the medium 99.

[0025] The printing unit 25 has a conveying section 32. The conveying section 32 is configured to convey the medium 99. The conveying section 32 conveys the medium 99 within the housing 26. In one example, the conveying section 32 conveys the medium 99 in the conveying direction D1. In one example, the conveying section 32 conveys the medium 99 intermittently. This is because, in one example, the head 28 is a serial head. In the case where the head 28 is a line head, the conveying section 32 can also convey the medium 99 continuously.

[0026] The conveying section 32 is housed within the housing 26. The conveying section 32 conveys the medium 99 unwound from the unwinding section 23. The conveying section 32 can also unwind the medium 99 from the first roll body R1, thereby causing the unwinding section 23 to unwind the medium 99. The conveying section 32 is positioned opposite the printing section 27. In one example, the conveying section 32 is located directly below the printing section 27.

[0027] The conveying unit 32 conveys the medium at a predetermined conveying speed. This conveying speed is, for example, expressed as the average speed of the medium 99. The conveying speed is set, for example, by the user operating the input unit 14.

[0028] The conveying unit 32 has a first pulley 33, a second pulley 34, and a belt 35. The first pulley 33 and the second pulley 34 are arranged, 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.

[0029] The belt 35 supports the medium 99. Specifically, the belt 35 is configured to adsorb the medium 99. In one example, the belt 35 adsorbs the medium 99 using an adhesive. An adhesive is applied to the surface of the belt 35. The belt 35 holds the medium 99 by adsorbing it, thus stabilizing the posture of the medium 99. The belt 35 can adsorb the medium 99 either by electrostatic attraction or by negative pressure generated by suction. The belt 35 transports the medium 99 by rotating while adsorbing it. The conveying unit 32 is not limited to transporting the medium 99 via the belt 35; for example, the medium 99 can also be transported via rollers.

[0030] The printing unit 25 may also have more than one printing guide roller. 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 it. The printing guide rollers guide the medium 99 from the unwinding unit 21 to the printing unit 25, or from the printing apparatus 12 to the drying apparatus 13.

[0031] The printing guide rollers can be located either inside or outside the housing 26. In one example, the first printing guide roller 36 and the second printing guide roller 37 are located outside the housing 26. The first printing guide roller 36 guides the medium 99, for example, by supplying the medium 99 from outside the housing 26 to inside the housing 26. In one example, the first printing guide roller 36 guides the medium 99 unwound from the unwinding section 23 into the housing 26. The second printing guide roller 37 guides the medium 99, for example, by discharging it from inside the housing 26 to outside the housing 26. More specifically, the second printing guide roller 37 guides the printed medium 99 to outside the housing 26.

[0032] The printing unit 25 includes a printing control unit 38. The printing control unit 38 controls the printing unit 25. Specifically, the printing control unit 38 controls the printing unit 27 and the transport unit 32. In addition to the printing unit 25, the printing control unit 38 can also control the unwinding unit 21. For example, the printing control unit 38 can also control the unwinding unit 23.

[0033] The printing control unit 38 may also be composed of one or more processors that execute various processes according to a computer program. The printing control unit 38 may also be composed of one or more dedicated hardware circuits, such as application-specific integrated circuits (ASICs), that execute at least a portion of the various processes. The printing control unit 38 may also be composed of a circuit that includes a processor and a combination of hardware circuits. The processor includes a CPU and memories such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. Memory, or computer-readable medium, includes all usable readable media that can be accessed by a general-purpose or special-purpose computer.

[0034] The printing control unit 38 communicates with the drying device 13. The printing control unit 38 can also send various signals to the drying device 13. By sending signals to the drying device 13, the printing control unit 38 notifies the printing device 12 of its status. The printing control unit 38 receives various signals from the drying device 13. By receiving signals from the drying device 13, the printing control unit 38 can monitor the status of the drying device 13.

[0035] Drying device

[0036] The drying apparatus 13 has a winding unit 41. The winding unit 41 is configured to wind up the medium 99. By winding up the medium 99, the winding unit 41 forms a roll.

[0037] The winding unit 41 has a winding housing 42. The winding housing 42 houses the second roll R2. The second roll R2 is a roll formed by winding and overlapping the printed media 99.

[0038] The winding unit 41 has a winding section 43. The winding section 43 winds up the medium 99. 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 housing 42. The winding shaft 44 rotatably supports the second roll body R2. By rotating the winding shaft 44, the medium 99 is wound up. That is, the second roll body R2 rotates simultaneously with the rotation of the winding shaft 44. The medium 99 is conveyed in the drying apparatus 13 by being wound up by the winding section 43.

[0039] The winding section 43 is driven in such a way that it winds the medium 99 at a speed faster than the conveying section 32. Specifically, the winding section 43 is driven at a winding speed faster than the conveying speed. This applies tension to the medium 99 between the conveying section 32 and the winding section 43. By applying tension to the medium 99, the posture of the medium 99 is stabilized. In one example, by applying tension to the medium 99, it is easier to peel the medium 99 off the belt 35.

[0040] The take-up section 43 may also include a tension adjusting roller 45. The tension adjusting roller 45 can be located either inside or outside the take-up housing 42. Media 99 is wound onto the tension adjusting roller 45. Specifically, the media 99 before being wound up by the take-up shaft 44 is wound onto the tension adjusting roller 45. The tension adjusting roller 45 is configured to allow for displacement. By displacing itself, the tension applied to the media 99 is adjusted. This stabilizes the take-up shaft 44, making it easier to wind up the media 99.

[0041] The drying apparatus 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 printed by the printing apparatus 12. After being dried by the drying unit 46, the medium 99 is wound up by the winding unit 41.

[0042] The drying unit 46 includes a drying oven 47. The drying oven 47 is adjacent to the winding housing 42. In one example, the drying oven 47 and the winding housing 42 are arranged in the transport direction D1. Printed media 99 enters the drying oven 47. Media 99 transported from the printing device 12 enters the drying oven 47. In the drying oven 47, the media 99 is transported via the transport section 32 and the winding section 43.

[0043] The drying unit 46 has a heating element 48. The heating element 48 is housed in a drying oven 47. The heating element 48 heats the medium 99 within the drying oven 47. As a result, the liquid adhering to the medium 99 evaporates. Consequently, the color components are fixed onto the medium 99. The heating element 48 will be described in detail later.

[0044] The drying unit 46 may also have an exhaust pipe 49. The exhaust pipe 49 is a pipe for venting exhaust gas from the drying furnace 47. The exhaust pipe 49 extends from the drying furnace 47. The exhaust pipe 49 is mounted on the drying furnace 47. In one example, the exhaust pipe 49 is mounted on the upper surface of the drying furnace 47. This facilitates the venting of steam within the drying furnace 47. This is because the steam, heated by the heating unit 48, easily floats to the top. By venting the steam from the drying furnace 47, the drying of the medium 99 is promoted.

[0045] The drying unit 46 may also 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 mounted on the drying oven 47. In one example, the exhaust fan 50 is mounted on the upper surface of the drying oven 47. The exhaust fan 50 is mounted on the exhaust duct 49. The exhaust fan 50 may be located either outside or inside the exhaust duct 49.

[0046] The drying unit 46 may also have more than one drying guide roller. In one example, the drying unit 46 has a first drying guide roller 51 and a second drying guide roller 52. Similar to the printing guide roller, the drying guide roller is configured to guide the medium 99. The drying guide roller guides the medium 99 by contacting it. The drying guide roller guides the medium 99 from the printing device 12 to the drying device 13, or from the drying unit 46 to the winding unit 41.

[0047] The drying guide rollers can be located either 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, by supplying the medium 99 from outside the drying oven 47 into the drying oven 47. In one example, the first drying guide roller 51 guides the medium 99 conveyed from the printing apparatus 12 into the drying oven 47. The second drying guide roller 52 guides the medium 99, for example, by discharging it 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.

[0048] The drying unit 46 has a drying control unit 53. The drying control unit 53 controls the drying unit 46. Specifically, the drying control unit 53 controls the heating unit 48 and the exhaust fan 50. In addition to the drying unit 46, the drying control unit 53 can also control the winding unit 41. For example, the drying control unit 53 can also control the winding unit 43. Similar to the printing control unit 38, the drying control unit 53 can be composed of a processor, hardware circuitry, or a combination of both.

[0049] The drying control unit 53 can also communicate with the printing apparatus 12. Specifically, the drying control unit 53 can also communicate with the printing control unit 38. The drying control unit 53 sends various signals to the printing control unit 38. By sending signals to the printing control unit 38, the drying control unit 53 notifies the printing apparatus 13 of its status. The drying control unit 53 receives various signals from the printing control unit 38. By receiving signals from the printing control unit 38, the drying control unit 53 can monitor the status of the printing apparatus 12.

[0050] Next, the heating element 48 will be described.

[0051] In order to dry the medium 99, the heating unit 48 heats the medium 99 by maintaining it at a high temperature. The heating unit 48 heats the medium 99 by rapidly raising its temperature. By rapidly raising the temperature of the medium 99, the need for a larger drying oven 47 and a decrease in drying efficiency are prevented. If the temperature of the medium 99 is raised slowly, it is necessary to either increase the size of the drying oven 47 or reduce the conveying speed.

[0052] The heating unit 48 heats the medium 99 at a high temperature to rapidly raise its temperature. However, if the temperature of the medium 99 is raised too rapidly, it may be overheated, potentially leading to deterioration. Therefore, the heating unit 48 heats the medium 99 to maintain it at a high temperature while suppressing deterioration. In one example, the heating unit 48 heats the medium 99 to dry the pigment-based ink printed on it, maintaining it at a temperature above 150 degrees Celsius. If the medium 99 is a blend of 65% polyester and 35% cotton, deterioration may occur if the temperature exceeds 170 degrees Celsius. For example, the medium 99 may yellow if its temperature exceeds 170 degrees Celsius. The heating unit 48 heats the medium 99 to maintain it between 150 and 170 degrees Celsius.

[0053] like Figure 2As shown, the heating unit 48 has multiple heating mechanisms. The heating unit 48 has an upstream heating mechanism 55, a downstream heating mechanism 56, and an intermediate heating mechanism 57.

[0054] Multiple heating mechanisms are arranged in the conveying direction D1. Specifically, they are arranged in the order of upstream heating mechanism 55, intermediate heating mechanism 57, and downstream heating mechanism 56 in the conveying direction D1. Therefore, the downstream heating mechanism 56 is located downstream of the upstream heating mechanism 55 in the conveying direction D1. The intermediate heating mechanism 57 is located between the upstream heating mechanism 55 and the downstream heating mechanism 56 in the conveying direction D1.

[0055] The heating mechanism has one or more heating elements. The heating elements are configured to heat the medium 99. The upstream heating mechanism 55 has two upstream heating elements. The downstream heating mechanism 56 has one downstream heating element. The intermediate heating mechanism 57 has four intermediate heating elements. In one example, the upstream heating mechanism 55 has a first upstream heating element 60 and a second upstream heating element 61. The downstream heating mechanism 56 has a first downstream heating element 62. The intermediate heating mechanism 57 has 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.

[0056] The upstream heating mechanism 55 has an upstream heating component located at a predetermined distance from the medium 99. In one example, the upstream heating mechanism 55 has a first upstream heating component 60 located at a first distance L1 perpendicular to the medium 99. The upstream heating mechanism 55 also has a second upstream heating component 61 located at a second distance L2 perpendicular to the medium 99. The second upstream heating component 61 may also be located at the 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, and the second distance L2 is 68 mm.

[0057] The smaller the distance between the heating element and the medium 99, the easier it is to heat the medium 99. That is, the smaller the distance between the heating element and the medium 99, the easier it is for the temperature of the medium 99 to rise. Therefore, the first upstream heating element 60 is more effective at heating the medium 99 than the second upstream heating element 61.

[0058] The downstream heating mechanism 56 has a downstream heating component located at a distance greater than a predetermined distance from the medium 99. In one example, the downstream heating mechanism 56 has a first downstream heating component 62 located at a vertical distance L2 relative to the medium 99. The distance between the first downstream heating component 62 and the medium 99 only needs to be greater than the first distance L1. Therefore, the first upstream heating component 60 is more effective at heating the medium 99 compared to the downstream heating component.

[0059] The intermediate heating mechanism 57 has intermediate heating components located at a distance greater than a predetermined distance from the medium 99. In one example, the intermediate heating mechanism 57 has a first intermediate heating component 63 located at a vertical distance L2 from the medium 99. The intermediate heating mechanism 57 has a second intermediate heating component 64 located at a vertical distance L2 from the medium 99. The intermediate heating mechanism 57 has a third intermediate heating component 65 located at a vertical distance L2 from the medium 99. The intermediate heating mechanism 57 has a fourth intermediate heating component 66 located at a vertical distance L2 from the medium 99. The distances between the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66 and the medium 99 only need to be greater than the first distance L1, or they can be different from each other. Therefore, the first upstream heating element 60 is more effective at heating the medium 99 than the intermediate heating element.

[0060] Multiple heating elements are arranged in the conveying direction D1. In one example, the multiple heating elements are arranged at equal intervals in the conveying direction D1. For example, the multiple heating elements are arranged at 140mm 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 arranged in this order in the conveying direction D1. The first upstream heating element 60 is located at the upstreammost position among the multiple heating elements. The first downstream heating element 62 is located at the downstreammost position among the multiple heating elements. The heating element located at the upstreammost position in the conveying direction D1 is located closest to the medium 99. As a result, the heating unit 48 can rapidly raise the temperature of the portion of the medium 99 that has just entered the drying oven 47. The heating elements other than the upstreammost heating element in the conveying direction D1 are located at relatively separate positions relative to the medium 99. As a result, the possibility of the heating unit 48 overheating the medium 99 is reduced.

[0061] The heating element is an infrared heater. Multiple heating elements have the same structure. 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 all infrared heaters. The heating elements heat the medium 99 by irradiating it with infrared light. The heating elements are located opposite the printed surface of the medium 99. In one example, the heating element is located opposite the upper surface of the medium 99. The heating elements irradiate the printed surface of the medium 99 with infrared light. The heating element is not limited to an infrared heater; for example, it could also be a blower that blows hot air onto the medium 99.

[0062] The heating element is driven to heat the medium 99 at a predetermined set temperature. The set temperature is the 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 at 400 degrees.

[0063] The upstream heating element is driven to heat the medium 99 at a temperature higher than that of the intermediate heating element. The set temperature of the upstream heating element is higher than that of the intermediate heating element. In one example, the set temperature of the first upstream heating element 60 is higher than the set temperatures of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66. The set temperature of the second upstream heating element 61 is higher than the set temperatures of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66.

[0064] The higher the set temperature of the heating element, the easier it is to heat the medium 99. That is, 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 is more effective at heating the medium 99 than the intermediate heating element. As a result, the heating section 48 can rapidly raise the temperature of the portion of the medium 99 that immediately enters the drying oven 47. Furthermore, by setting the set temperature of the intermediate heating element lower than that of the upstream heating element, the possibility of the medium 99 being overheated is reduced.

[0065] The downstream heating element is driven to heat the medium 99 at a temperature higher than that of the intermediate heating element. The set temperature of the downstream heating element is higher than that of the intermediate heating element. In one example, the set temperature of the first downstream heating element 62 is higher than the set temperatures of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66.

[0066] The portion heated by the downstream heating element in medium 99 is easily cooled by outside air. In this respect, by setting the downstream heating element's temperature higher than the intermediate heating element's temperature, the possibility of temperature drop in medium 99 is reduced.

[0067] The upstream heating element is driven to heat the medium 99 at a temperature higher than that of the downstream heating element. The set temperature of the upstream heating element is higher than that of the downstream heating element. In one example, the set temperature of the first upstream heating element 60 is higher than that of the first downstream heating element 62. The set temperature of the second upstream heating element 61 is higher than that of the first downstream heating element 62. As a result, the heating unit 48 can rapidly raise the temperature of the portion of the medium 99 that immediately enters the drying oven 47.

[0068] The capacity of the intermediate heating element can be smaller than the capacity of the upstream heating element and the downstream heating element. In one example, the capacities of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66 can be smaller than the capacities of the first upstream heating element 60 and the second upstream heating element 61. The capacities of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66 can be smaller than the capacity of the first downstream heating element 62. Since the set temperature of the intermediate heating element is relatively low, a heating element with a smaller capacity can be used in the intermediate heating element. This reduces the power consumption of the heating unit 48. Alternatively, the capacity of some of the multiple intermediate heating elements can be smaller than the capacities of the upstream heating element and the downstream heating element.

[0069] The set temperature is set by the drying control unit 53. The set temperature of the upstream heating element is set by the drying control unit 53 in a manner that is higher than the set temperature of the intermediate heating element. The set temperature of the downstream heating element is set by the drying control unit 53 in a manner that is higher than the set temperature of the intermediate heating element. The set temperature of the upstream heating element is set by the drying control unit 53 in a manner that is higher than the set temperature of the downstream heating element.

[0070] The set temperature can also be set for each heating mechanism. In one example, the set temperature is set for 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 component 60 is the same as the set temperature of the second upstream heating component 61. The set temperatures of the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66 are the same.

[0071] The heating element extends in the width direction D2. The width direction D2 is a direction different from the conveying direction D1. The width direction D2 is a direction that serves as an indicator of 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.

[0072] like Figure 3 As shown, the heating element is configured to be larger than the entire width of the medium 99 in the width direction D2. Specifically, the heating element is configured as a strip longer than the maximum width of the medium 99 that the drying device 13 can accommodate. Although in Figure 3The diagram shows the first upstream heating element 60, but other heating elements are also configured as strips longer than the maximum width of the medium 99. In one example, when the medium 99 is viewed from above, the heating element is a strip with each end protruding more than 100 mm.

[0073] The heating element radiates infrared rays radially. For example, the heating element is located in... Figure 3 Infrared radiation is irradiated as indicated by the black arrows. Therefore, in the width direction D2, the portion of the medium 99 located at the ends receives less heat from the heating element compared to the portion located in the center of the medium 99. At this point, by making the heating element elongated in the width direction D2, the heat gradient received by the medium 99 is reduced.

[0074] The heating element has a central portion 70 and two end portions 71. The central portion 70 is the portion located at the center of the heating element in the width direction D2. The end portions 71 are the portions located at the ends of the heating element in the width direction D2. The two end portions 71 are located at positions that sandwich the central portion 70 in the width direction D2. In one example, the two end portions 71 are portions extending 400 mm from each end of the heating element.

[0075] The heating element is configured such 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 such that the amount of infrared radiation generated from the end portion 71 is greater than the amount of infrared radiation generated from the central portion 70. For example, the heating element is configured such that the output of the end portion 71 is more than 120% higher than the output of the central portion 70. This reduces the heat gradient received by the medium 99. The heating element can be driven either to set the temperature of the central portion 70 to a set temperature or to set the temperature of the end portion 71 to a set temperature.

[0076] The heating element has a heating wire 72. An electric current flows through the heating wire 72, thereby generating heat. The heating wire 72 is, for example, a coil. The heating wire 72 extends in the width direction D2. The heating wire 72 is configured such that, in the width direction D2, the density of the portion located at the ends is greater than the density of the portion located at the center. In one example, the heating wire 72 is configured such that the number of turns per unit length in the portion corresponding to the central portion 70 is less than the number of turns per unit length in the portion corresponding to the end portion 71. Specifically, the heating wire 72 has a first density portion 73 and two second density portions 74. The first density portion 73 is located at the center in the width direction D2. The first density portion 73 corresponds to the central portion 70 in the heating wire 72. The second density portions 74 are located at the ends in the width direction D2. The second density portions 74 correspond to the end portions 71 in the heating wire 72. The density of the second density portions 74 is greater than the density of the first density portions 73. The temperature of the end portion 71 in the heating element is higher than that of the central portion 70 due to the electric heating wire 72.

[0077] The heating element has a cylindrical component 75. The cylindrical component 75 houses the heating wire 72. The cylindrical component 75 is configured to irradiate infrared rays by being heated by the heating wire 72. The cylindrical component 75 is made of, for example, ceramic. The cylindrical component 75 extends in the width direction D2. The cylindrical component 75 is triangular when viewed from the width direction D2. In this case, compared to the case where the cylindrical component 75 is cylindrical, the rigidity is greater. That is, the heating element is less prone to bending in the width direction D2.

[0078] Since the cylindrical component 75 is a triangular cylinder, it has three circumferential surfaces. These three surfaces include a bottom surface 76. That is, the cylindrical component 75 has a bottom surface 76. The bottom surface 76 of the cylindrical component 75 is located opposite the medium 99. Specifically, the cylindrical component 75 is located with its bottom surface 76 facing downwards. Therefore, compared to the case where the corner portions of the cylindrical component 75 face the medium 99, it is easier to irradiate the medium 99 with infrared light.

[0079] like Figure 2As shown, the first upstream heating element 60 can also be located downstream of the bottom surface 76 in the conveying direction D1. The first upstream heating element 60 can also be located such that the vertical line S1 extending from its bottom surface 76 extends downstream in the conveying direction D1. In this case, the first upstream heating element 60 irradiates infrared light into the radiation area of ​​the second upstream heating element 61. That is, the radiation area of ​​the first upstream heating element 60 overlaps with the radiation area of ​​the second upstream heating element 61. As a result, the temperature of the medium 99 entering the drying oven 47 rises rapidly. In one example, the first upstream heating element 60 is located where the vertical line S1 is inclined at 1 to 10 degrees relative to the vertical direction of the medium 99. Preferably, the first upstream heating element 60 is located where the vertical line S1 is inclined at 6 degrees relative to the vertical direction of the medium 99. The bottom surface 76 of the first upstream heating element 60 faces downstream in the conveying direction D1 while opposite to the medium 99. Other heating elements besides the first upstream heating element 60 are located where the vertical line S1 extends vertically relative to the medium 99. That is, the heating components other than the first upstream heating component 60 are located with their respective bottom surfaces 76 parallel to the medium 99.

[0080] The heating mechanism has one or more reflectors. In one example, the heating mechanism has the same number of reflectors as the heating element. 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.

[0081] The reflectors are located at positions that reflect infrared radiation generated by the heating components toward the medium 99. An upstream reflector reflects infrared radiation generated by an upstream heating component toward the medium 99. A downstream reflector reflects infrared radiation generated by a downstream heating component toward the medium 99. An intermediate reflector reflects infrared radiation generated by an intermediate heating component toward the medium 99. Specifically, a first upstream reflector 77 reflects infrared radiation generated by a first upstream heating component 60 toward the medium 99. A second upstream reflector 78 reflects infrared radiation generated by a second upstream heating component 61 toward the medium 99. A first downstream reflector 79 reflects infrared radiation generated by a first downstream heating component 62 toward the medium 99. A first intermediate reflector 80 reflects infrared radiation generated by a first intermediate heating component 63 toward the medium 99. A second intermediate reflector 81 reflects infrared radiation generated by a second intermediate heating component 64 toward the medium 99. A third intermediate reflector 82 reflects infrared radiation generated by a third intermediate heating component 65 toward the medium 99. A fourth intermediate reflector 83 reflects infrared radiation generated by a fourth intermediate heating component 66 toward the medium 99.

[0082] The first upstream reflector 77 can also be located at a position that reflects the infrared radiation generated by the first upstream heating element 60 downstream in the conveying direction D1. The first upstream reflector 77 can also be located with its optical axis G1 downstream in the conveying direction D1. In this case, the first upstream reflector 77 reflects the infrared radiation generated by the first upstream heating element 60 towards the radiation area of ​​the second upstream heating element 61 irradiating infrared radiation. That is, the radiation areas of the first upstream heating element 60 and the second upstream heating element 61 overlap. As a result, the temperature of the medium 99 entering the drying oven 47 rises rapidly. In one example, the first upstream reflector 77 is located at a position where the optical axis G1 is tilted by 1 to 10 degrees relative to the vertical direction of the medium 99. Preferably, the first upstream reflector 77 is located at a position where the optical axis G1 is tilted by 6 degrees relative to the vertical direction of the medium 99. The first upstream reflector 77 is located at a position where the optical axis G1 overlaps with the vertical line S1 of the first upstream heating element 60. Other reflectors besides the first upstream reflector 77 are located where their respective optical axes G1 are perpendicular to the medium 99. The other reflectors, besides the first upstream reflector 77, are located where their respective optical axes G1 and vertical lines S1 overlap. By aligning the optical axis G1 with the vertical line S1, the infrared reflection efficiency based on the reflectors is improved.

[0083] The heating mechanism has 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 can be composed of a processor or hardware circuitry.

[0084] The controller controls the heating element to bring it to a 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 duty cycle of its power supply.

[0085] The upstream controller 87 controls the temperature of the upstream heating element. Specifically, the upstream controller 87 provides unified control over the temperatures of the first upstream heating element 60 and the second upstream heating element 61. The upstream controller 87 controls both the first and second upstream heating elements 60 and 61 at a common set temperature. The upstream controller 87 controls the first and second upstream heating elements 60 and 61 in such a way that the average temperature of the first and second upstream heating elements 60 and 61 becomes the set temperature. By having a single upstream controller 87 control both the first and second upstream heating elements 60 and 61, the upstream heating mechanism 55 does not need multiple upstream controllers 87. Therefore, the structure of the upstream heating mechanism 55 is simplified.

[0086] 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.

[0087] The intermediate controller 89 controls the temperature of the intermediate heating components. Specifically, the intermediate controller 89 uniformly controls the temperatures of the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66. The intermediate controller 89 controls the temperatures of the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66 with a common set temperature. The intermediate controller 89 controls the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66 in such a way that the average temperature of the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66 becomes the set temperature. By having a single intermediate controller 89 control the first intermediate heating component 63, the second intermediate heating component 64, the third intermediate heating component 65, and the fourth intermediate heating component 66, the intermediate heating mechanism 57 does not need to have multiple intermediate controllers 89. Therefore, the structure of the intermediate heating mechanism 57 becomes simple.

[0088] like Figure 4 As shown, the drying device 13 dries the medium 99 by maintaining it at a temperature above 150 degrees and below 170 degrees for an extended period of time. Figure 4 The graph shown represents the temperature change of medium 99 over time. The temperature of medium 99 is measured by a thermocouple mounted on medium 99.

[0089] exist Figure 4 In the example shown, the drying apparatus 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 element 60 and the second upstream heating element 61 are, for example, 490°C. The set temperatures of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66 are, for example, 395°C. The set temperature of the first downstream heating element 62 is, for example, 445°C. The conveying speed of the medium 99 is, for example, 10.2 mm / s. According to 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.

[0090] like Figure 5 As shown, the drying device 13 dries the medium 99 by maintaining it at a temperature above 150 degrees and below 170 degrees for an extended period of time. Figure 5 The curve shown is Figure 4 Similarly, the graph shown represents the temperature change of medium 99 over time.

[0091] exist Figure 5 In the example shown, the drying apparatus 13 maintains the medium 99 at a temperature between 150°C and 170°C for 45.0 seconds. The set temperatures of the first upstream heating element 60 and the second upstream heating element 61 are, for example, 500°C. The set temperatures of the first intermediate heating element 63, the second intermediate heating element 64, the third intermediate heating element 65, and the fourth intermediate heating element 66 are, for example, 370°C. The set temperature of the first downstream heating element 62 is, for example, 455°C. The conveying speed of the medium 99 is, for example, 20.0 mm / s. According to this example, the color difference ΔE00 between the medium 99 before drying and the medium 99 after drying is 0.63.

[0092] The role and effects of the embodiments

[0093] Next, the function and effects of the above embodiments will be explained.

[0094] (1) The upstream heating mechanism 55 has a first upstream heating element 60, which is located at a predetermined distance from the medium 99. The downstream heating mechanism 56 has a downstream heating element, which is located at a distance greater than the predetermined distance from the medium 99. The intermediate heating mechanism 57 has an intermediate heating element, which is located at a distance greater than the predetermined distance from the medium 99. The set temperature of the first upstream heating element 60 is greater than the set temperature of the intermediate heating element. The set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element. In the drying apparatus 13, the smaller the distance between the heating element and the medium 99, the easier it is for the temperature of the medium 99 to rise. In the drying apparatus 13, the higher the set temperature of the heating element, the easier it is for the temperature of the medium 99 to rise. According to the above structure, the temperature of the medium 99 rises rapidly through the first upstream heating element 60, which is relatively close to the medium 99 and has a relatively high set temperature. The possibility of excessive temperature rise of the medium 99 is reduced through the intermediate heating element, which is relatively far from the medium 99 and has a relatively low set temperature. By using a downstream heating element that is relatively far from the medium 99 and has a relatively high set temperature, the possibility of the medium 99 cooling down is reduced. In this way, the drying apparatus 13 can effectively dry the medium 99.

[0095] (2) The set temperature of the upstream heating element is greater than the set temperature of the downstream heating element. According to the above structure, the temperature of the medium 99 rises rapidly through the first upstream heating element 60.

[0096] (3) The upstream heating element, the downstream heating element, and the intermediate heating element are all infrared heaters. According to the above structure, for example, compared with the case where the heating element 48 heats the medium 99 by blowing hot air onto the medium 99, the heating element 48 can heat the medium 99 more simply.

[0097] (4) The downstream reflector is located at a position where its optical axis G1 is perpendicular to the medium 99. The intermediate reflector is located at a position where its optical axis G1 is perpendicular to the medium 99. The first upstream reflector 77 is located at a position where its optical axis G1 is downstream of the conveying direction D1. According to the above structure, the radiation area of ​​the first upstream heating element 60 overlaps with the radiation area of ​​a heating element located downstream of the first upstream heating element 60, such as the second upstream heating element 61. As a result, the temperature of the medium 99 rises rapidly.

[0098] (5) The upstream heating element, downstream heating element, and intermediate heating element are each configured such that, in the width direction D2, the temperature of the end portion 71 is higher than that of the central portion 70. Since infrared radiation is generated radially from the heating elements, the amount of radiation received by the end portion of the medium 99 is more likely to be less than that received by the central portion of the medium 99. In this respect, according to the above structure, the amount of radiation received by the end portion of the medium 99 is increased. Therefore, the heating section 48 can heat the medium 99 uniformly.

[0099] (6) When viewed from the width direction D2, the upstream heating element, the downstream heating element, and the intermediate heating element are each approximately triangular with a base 76, and are located opposite the medium 99 to the base 76. According to the above structure, the amount of radiation received by the medium 99 increases.

[0100] (7) The first upstream heating element 60 is located downstream of the conveying direction D1, with its bottom surface 76 facing the downstream side. According to the above structure, the temperature of the medium 99 is rapidly increased by the first upstream heating element 60 and a heating element located downstream of the first upstream heating element 60, such as the second upstream heating element 61.

[0101] (8) The capacity of the intermediate heating element is less than that of the upstream heating element and less 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, according to the above structure, the power consumption of the heating unit 48 is reduced.

[0102] Change example

[0103] The above embodiments can be modified and implemented in the following ways. The above embodiments and the following modifications can be combined and implemented with each other without technical inconsistencies.

[0104] The heating mechanism can also have the same number of controllers as the heating elements. Multiple heating elements can also be driven separately at individually set temperatures.

[0105] The unwinding section 23 may also have a tension adjusting roller, just like the winding section 43.

[0106] The liquid ejected by the head 28 is not limited to ink; for example, it can be a liquid formed by dispersing or mixing functional material particles in a liquid. For example, the head 28 can also eject a liquid containing materials such as electrode materials or pixel materials used in the manufacture of liquid crystal displays, electroluminescent displays, and surface-emitting displays in a dispersed or dissolved form.

[0107] Although the unwinding unit 21 has an unwinding housing 22, it is not limited thereto. For example, the first roll body R1 can also be configured without covering.

[0108] Although the winding unit 41 has a winding housing 42, it is not limited thereto. For example, the second roll body R2 can also be configured without covering.

[0109] While the cylindrical component 75 of the heating element is a triangular shape with a vertex when viewed from the width direction D2, it is not limited to this and may also be a triangular shape with rounded corners without a vertex. That is, the cylindrical component 75 only needs to be a roughly triangular shape with a base 76 when viewed from the width direction D2.

[0110] Technical ideas

[0111] The following describes the technical concepts and effects learned based on the above embodiments and modifications.

[0112] (A) A drying apparatus includes: a drying oven into which a conveyed medium enters; 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 conveying direction of the medium; and an intermediate heating mechanism located between the upstream and downstream heating mechanisms in the conveying 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 greater than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element. In the drying apparatus, the smaller the distance between the heating element and the medium, the easier it is for the medium temperature to rise. In the drying apparatus, the larger the set temperature of the heating element, the easier it is for the medium temperature to rise. According to the above structure, the upstream heating element, which is relatively close to the medium and has a relatively high set temperature, causes the medium temperature to rise rapidly. The intermediate heating element, which is relatively far from the medium and has a relatively low set temperature, reduces the possibility of excessive temperature rise in the medium. The downstream heating element, which is relatively far from the medium and has a relatively high set temperature, reduces the possibility of temperature drop in the medium. In this way, the drying apparatus can effectively dry the medium.

[0113] (B) In the above-described drying apparatus, the set temperature of the upstream heating element can also be greater than the set temperature of the downstream heating element. According to this structure, the temperature of the medium rises rapidly through the upstream heating element.

[0114] (C) In the above-described drying apparatus, the upstream heating element, the downstream heating element, and the intermediate heating element may also be infrared heaters. According to this structure, for example, compared to the case where the heating section heats the medium by blowing hot air onto it, the heating section can heat the medium more simply.

[0115] (D) In ​​the above-described drying apparatus, the heating unit may also include: an upstream reflector that reflects infrared radiation generated by the upstream heating element toward the medium; a downstream reflector that reflects infrared radiation generated by the downstream heating element toward the medium; and an intermediate reflector that reflects infrared radiation generated by the intermediate heating element toward the medium. The downstream reflector is located at a position where its optical axis is perpendicular to the medium, the intermediate reflector is located at a position where its optical axis is perpendicular to the medium, and the upstream reflector is located downstream of the conveying direction. According to this structure, the radiation area of ​​the upstream heating element overlaps with the radiation area of ​​a heating element located downstream of the upstream heating element. As a result, the temperature of the medium rises rapidly.

[0116] (E) In the above-described drying apparatus, the upstream heating element, the downstream heating element, and the intermediate heating element may be configured to extend in a width direction different from the conveying direction, and the temperature of the end portions in this width direction is higher than that of the central portion. Since infrared radiation is generated radially from the heating elements, the amount of radiation received by the end portions of the medium tends to be smaller than that received by the central portion. In this respect, according to the above structure, the amount of radiation received by the end portions of the medium is increased. Therefore, the heating element can heat the medium uniformly.

[0117] (F) In the above-described drying apparatus, the upstream heating element, the downstream heating element, and the intermediate heating element may each extend in a width direction different from the conveying direction, and when viewed from the width direction, have a generally triangular shape with a base, and be positioned opposite the base to the medium. According to this structure, the amount of radiation received by the medium increases.

[0118] (G) In the above-described drying apparatus, the upstream heating element may be located downstream of the conveying direction, with its bottom surface facing the direction of transport. According to this structure, the temperature of the medium rises rapidly through the upstream heating element and the heating element located downstream of it.

[0119] (H) In the above-described drying apparatus, the capacity of the intermediate heating element can be smaller than that of the upstream heating element and also smaller than that of the downstream heating element. Since the set temperature of the intermediate heating element is relatively low, its capacity can be reduced. Therefore, according to the above structure, the power consumption of the heating section is reduced.

[0120] (I) A printing system comprising: a printing apparatus for printing an image on a medium; a drying apparatus for drying the printed medium, the printing apparatus comprising: a housing; a printing section for printing an image on the medium within the housing, the drying apparatus comprising: a drying oven into which a medium conveyed from the printing apparatus enters; a heating section for heating the medium within the drying oven, the heating section comprising: an upstream heating mechanism; a downstream heating mechanism located downstream of the upstream heating mechanism in the medium conveying direction; and an intermediate heating mechanism located between the upstream and downstream heating mechanisms in the conveying direction, the upstream heating mechanism having an upstream heating element located at a predetermined distance from the medium, the downstream heating mechanism having a downstream heating element located at a distance greater than the predetermined distance from the medium, the intermediate heating mechanism having an intermediate heating element located at a distance greater than the predetermined distance from the medium, the set temperature of the upstream heating element being greater than the set temperature of the intermediate heating element, and the set temperature of the downstream heating element being greater than the set temperature of the intermediate heating element. Based on the above structure, the same effect as the drying device described above can be obtained.

[0121] Symbol Explanation

[0122] 11…Printing system; 12…Printing apparatus; 13…Drying apparatus; 14…Input section; 21…Unwinding unit; 22…Unwinding housing; 23…Unwinding section; 24…Unwinding shaft; 25…Printing unit; 26…Frame; 27…Printing section; 28…Head; 29…Nozzle; 30…Nozzle face; 31…Carriage; 32…Conveying section; 33…First pulley; 34…Second pulley; 35…Belt; 36…First printing guide roller; 37…Second printing guide roller Guide roller; 38… Printing control unit; 41… Rewinding unit; 42… Rewinding housing; 43… Rewinding section; 44… Rewinding shaft; 45… Tension adjusting 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 unit; 55… Upstream heating mechanism; 56… Downstream heating mechanism; 57… Intermediate heating mechanism; 60… 61… Second upstream heating component; 62… First downstream heating component; 63… First intermediate heating component; 64… Second intermediate heating component; 65… Third intermediate heating component; 66… Fourth intermediate heating component; 70… Central portion; 71… End portion; 72… Heating wire; 73… First density portion; 74… Second density portion; 75… Cylinder component; 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… Conveying 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 apparatus, characterized in that, have: A drying oven into which the medium being transported enters; The heating section heats the medium within the drying oven. The heating element has: Upstream heating mechanism; The downstream heating mechanism is located downstream of the upstream heating mechanism in the direction of medium transport; An intermediate heating mechanism is located between the upstream heating mechanism and the downstream heating mechanism in the conveying direction. The upstream heating mechanism has an upstream heating component, which is located at a predetermined distance from the medium. The downstream heating mechanism has a downstream heating component, which is located at a distance from the medium greater than the predetermined distance. The intermediate heating mechanism includes an intermediate heating component, which is located at a distance from the medium greater than the predetermined distance. The set temperature of the upstream heating element is greater than the set temperature of the intermediate heating element. The set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element.

2. The drying apparatus as described in claim 1, characterized in that, The set temperature of the upstream heating element is greater than the set temperature of the downstream heating element.

3. The drying apparatus as described in claim 1 or claim 2, characterized in that, The upstream heating component, the downstream heating component, and the intermediate heating component are all infrared heaters.

4. The drying apparatus as described in claim 3, characterized in that, The heating element has: An upstream reflector that reflects infrared radiation generated by the upstream heating element toward the medium; A downstream reflector that reflects infrared radiation generated by the downstream heating element toward the medium; An intermediate reflector reflects the infrared radiation generated by the intermediate heating element toward the medium. The downstream reflector is located at a position where its optical axis is perpendicular to the medium. The intermediate reflector is located at a position where its optical axis is perpendicular to the medium. The upstream reflector is located downstream of the conveying direction, with its optical axis pointing in the direction of transport.

5. The drying apparatus as described in claim 3, characterized in that, The upstream heating element, the downstream heating element, and the intermediate heating element are each configured to extend in a width direction that is different from the conveying direction, and in the width direction, the temperature of the end portion is higher than that of the central portion.

6. The drying apparatus as described in claim 3, characterized in that, The upstream heating component, the downstream heating component, and the intermediate heating component each extend in a width direction that is different from the conveying direction, and when viewed from the width direction, they are approximately triangular in shape with a base, and are located opposite the medium to the base.

7. The drying apparatus as described in claim 6, characterized in that, The upstream heating component is located downstream of the conveying direction, with its bottom surface facing the direction of transport.

8. The drying apparatus as described in claim 3, characterized in that, The capacity of the intermediate heating component is smaller than that of the upstream heating component and smaller than that of the downstream heating component.

9. A printing system, characterized in that, have: A printing apparatus that prints images on a medium; A drying device that dries the printed media. The printing apparatus includes: basket; The printing section prints images on a medium within the housing. The drying apparatus includes: A drying oven in which a medium conveyed from the printing apparatus enters; The heating section heats the medium within the drying oven. The heating element has: Upstream heating mechanism; The downstream heating mechanism is located downstream of the upstream heating mechanism in the direction of medium transport; An intermediate heating mechanism is located between the upstream heating mechanism and the downstream heating mechanism in the conveying direction. The upstream heating mechanism has an upstream heating component, which is located at a predetermined distance from the medium. The downstream heating mechanism has a downstream heating component, which is located at a distance from the medium greater than the predetermined distance. The intermediate heating mechanism includes an intermediate heating component, which is located at a distance from the medium greater than the predetermined distance. The set temperature of the upstream heating element is greater than the set temperature of the intermediate heating element. The set temperature of the downstream heating element is greater than the set temperature of the intermediate heating element.

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