Drying device

Abstract

To provide a drying device provided with a roller that can fit a roller body with a flange body together without idling.SOLUTION: A drying device that dries media on which images are formed in a high-temperature environment while being conveyed includes an endless conveying belt 11 that supports and conveys the media in a predetermined conveyance direction, and a roller around which the conveying belt 11 is wound; the roller has a cylindrical roller body 31 and a flange body 33 that is fitted to both ends of the roller body 31, and the thermal expansion coefficient of a portion 31b that is fitted on the inside at a fitting portion 39 between the roller body 31 and the flange body 33 is higher than the thermal expansion coefficient of a portion 33b that is fitted on the outside.SELECTED DRAWING: Figure 5B

Description

[Technical field]

[0001] The present invention relates to a drying device that dries a recording medium on which an image has been formed in a high-temperature environment while conveying the recording medium. [Background technology]

[0002] An image forming system including an inkjet image forming apparatus is provided with a drying device that dries an image formed on a recording medium with ink. The drying device described in Patent Document 1 includes a conveyor belt that is wound around multiple rollers and rotates with the rotation of the rollers. As the conveyor belt rotates, the recording medium supported by the conveyor belt is conveyed in a high-temperature environment, and the image formed with ink is dried.

[0003] The roller generally comprises a cylindrical roller body and flange bodies fitted to both ends of the roller body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-148189 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a drying device such as that described in Patent Document 1, the rollers are generally made of metal, and the roller body and the flange body are made of the same material in consideration of torque resistance. The flange body may have grooves formed along the circumferential direction to prevent meandering of the conveyor belt. There is also a demand for the roller body to be made of a low-density material in order to reduce the driving torque.

[0006] However, when the roller body and the flange body are made of the same material, if a low-density material is selected, the grooves for preventing meandering are easily worn, which reduces the durability of the meandering prevention effect. Also, when the roller body and the flange body are made of different materials, such as when the flange body is made of a hard material and the roller body is made of a low-density material, it is necessary to prevent the roller body from slipping relative to the flange body. This requires a pin driving operation to fix the roller body and the flange body, which increases the number of manufacturing steps.

[0007] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, an object of the present invention is to provide a drying device having a roller in which a roller body and a flange body can be fitted together without idling. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the drying device of the present invention is a drying device that dries a medium on which an image is formed in a high-temperature environment while transporting the medium, and is equipped with an endless transport belt that supports the medium and transports it in a predetermined transport direction, and a roller around which the transport belt is wrapped, and is characterized in that the roller has a cylindrical roller body and a flange body that is fitted to both ends of the roller body, and the thermal expansion coefficient of the part that is fitted on the inside at the fitting portion between the roller body and the flange body is higher than the thermal expansion coefficient of the part that is fitted on the outside.

[0009] In the present invention, the roller body may be fitted inside the flange body at the fitting portion, and a thermal expansion coefficient of the roller body may be higher than a thermal expansion coefficient of the flange body.

[0010] In the present invention, the flange body may have a groove extending along a circumferential direction for preventing meandering of the conveyor belt. Effect of the Invention

[0011] According to the present invention, when the roller is heated, the roller body is pressed against the flange body, bringing the roller body and the flange body into closer contact with each other, thereby preventing the roller body from slipping relative to the flange body. [Brief description of the drawings]

[0012] [Figure 1] 1 is a front view showing a schematic view of the inside of a drying device according to an embodiment of the present invention; [Diagram 2] 1 is a perspective view showing a transport unit (transport belt is not shown) in a drying device according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view showing a drive roller of a transport unit in the drying device according to the embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view showing a drive roller in the drying device according to one embodiment of the present invention. [Figure 5A] FIG. 2 is a cross-sectional view showing one end of a drive roller in a drying device according to one embodiment of the present invention. [Figure 5B] 4 is a cross-sectional view showing one end of a drive roller around which a conveyor belt is wound in a drying device according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a drying device according to an embodiment of the present invention will be described with reference to the drawings.

[0014] The overall configuration of the drying device 1 will be described with reference to Fig. 1. Fig. 1 is a front view that typically illustrates the inside of the drying device 1. Fr, Rr, L, and R in each drawing indicate the front side, rear side, left side, and right side of the drying device 1, respectively.

[0015] The drying device 1 includes a transport unit 3 that transports a medium (a cut sheet, a long sheet, etc.) on which an image has been formed by an inkjet method along a transport direction X1 (direction from right to left in Figure 1), and a heating unit 5 that dries the medium transported by the transport unit 3.

[0016] First, the transport unit 3 will be described with reference to Fig. 1 and Fig. 2. Fig. 2 is a perspective view showing the transport unit 3 (the transport belt 11 is not shown). As shown in Fig. 1 and Fig. 2, the transport unit 3 includes the transport belt 11 that transports the medium, a transport plate 13 that supports the transport belt 11, a suction device 15 that attracts the medium to the transport belt 11, and front and rear side plates 17 (see Fig. 2) on which these are supported.

[0017] First, the conveyor belt 11 will be described. The conveyor belt 11 is an endless belt, and a large number of through holes penetrating in the thickness direction are formed on the entire surface. Pins 19 (see FIG. 5B) are fixed at both ends of the conveyor belt 11 in the width direction X2 (direction perpendicular to the conveying direction X1) at a predetermined interval in the circumferential direction. The pins 19 have a disk-shaped head portion 19a and a hemispherical tip portion 19b, and are fixed so that the head portion 19a sandwiches the conveyor belt 11 from the outside and the inside. The tip portion 19b of the pin 19 protrudes inward from the inner circumferential surface of the conveyor belt 11. As shown in FIG. 1, the conveyor belt 11 is wound around a driving roller 21 and a driven roller 23.

[0018] Next, the driving roller 21 and the driven roller 23 will be described with reference to Figures 3, 4, 5A, and 5B. Figure 3 is a perspective view showing the driving roller 21, Figure 4 is a cross-sectional view showing the driving roller 21 and the driven roller 23, and Figures 5A and 5B are cross-sectional views showing one end of the driving roller 21. Here, the driving roller 21 will be mainly described, but the driven roller 23 has a similar configuration to the driving roller 21.

[0019] As shown in FIGS. 3 and 4, the drive roller 21 has a roller body 31, flange bodies 33 fitted to both ends of the roller body 31, and a rotation shaft .

[0020] First, the roller body 31 will be described. As shown in Fig. 4, the roller body 31 is formed in a cylindrical shape with a certain inner diameter, and has a main body portion 31a with a predetermined outer diameter, and a tube portion 31b erected along the inner circumference on the end face of the main body portion 31a. In other words, the outer diameter of the tube portion 31b is smaller than the outer diameter of the main body portion 31a, and the inner diameter is equal to the inner diameter of the main body portion 31a. The roller body 31 is made of a material (e.g., aluminum) that is relatively lightweight and can reduce inertia during rotation in order to reduce the driving torque.

[0021] Next, the flange body 33 will be described. As shown in Fig. 4, the flange body 33 has a disk portion 33a having a certain thickness, and a tubular portion 33b erected along the outer periphery on one end face of the disk portion 33a. The outer diameter of the tubular portion 33b of the flange body 33 is equal to the outer diameter of the main body portion 31a of the roller body 31, and the inner diameter is equal to the outer diameter of the tubular portion 31b of the roller body 31. The length of the tubular portion 33b of the flange body 33 is slightly longer than the length of the tubular portion 31b of the roller body 31. A through hole 33c is provided in the center of the disk portion 33a.

[0022] The flange body 33 is made of a material (e.g., SUS) that has a smaller coefficient of thermal expansion than the roller body 31 and is wear-resistant. For example, when the roller body 31 is made of aluminum, the coefficient of thermal expansion is 23.5(×10 -6 / °C), and when the flange body 33 is made of SUS304, the thermal expansion coefficient is 19.3 (×10 -6 / ℃).

[0023] 5A, a groove 37 is formed in the circumferential direction on the outer circumferential surface of the disk portion 33a. The groove 37 has a shallow portion 37a that is wide (the length along the longitudinal direction of the roller 21) and shallow, and a deep portion 37b that is provided in the center of the shallow portion 37a and is narrower and deeper than the shallow portion 37a.

[0024] As shown in Fig. 5A and Fig. 5B, both tubular portions 31b of the roller body 31 are fitted into the tubular portion 33b of the flange body 33. In the fitting portion 39 between the two, the portion fitted on the outside is the tubular portion 33b of the flange body 33, and the portion fitted on the inside is the tubular portion 31b of the roller body 31. The inner surface of the tubular portion 33b of the flange body 33 is in contact with the outer surface of the tubular portion 31b of the roller body 31, and the end face of the tubular portion 33b of the flange body 33 is in contact with the end face of the main body portion 31a of the roller body 31. The inner surface of the disc portion 33a of the flange body 33 is not in contact with the end face of the tubular portion 31b of the roller body 31, and a predetermined gap is provided between the two surfaces.

[0025] 5B, the pins 19 fixed to both ends of the conveyor belt 11 fit into the grooves 37 of the disk portions 33a of both flange bodies 33. In detail, a part of the head portion 19a of the pin 19 (a portion protruding from the inner surface of the conveyor belt 11) fits into the shallow portion 37a of the groove 37, and the tip portion 19b of the pin 19 fits into the deep portion 37b of the groove 37.

[0026] Next, the rotating shaft 35 will be described. The rotating shaft 35 is inserted into the through-holes 33c of the disk portions 33a of both flange bodies 33. As shown in Fig. 4, the rotating shaft 35 is fixed integrally to one of the flange bodies 33 (the front one in this example) so as to be rotatable. Both ends of the rotating shaft 35 are rotatably supported by the front and rear side plates 17 of the conveying unit 3 via bearings 41.

[0027] A drive gear (not shown) is fixed to one end of the rotation shaft 35 of the drive roller 21. The drive gear is connected to a motor (both not shown) via a gear train. When the motor is driven and the drive gear rotates via the gear train, the rotation shaft 35 rotates together with the drive gear. Then, the flange body 33 rotates together with the rotation shaft 35, and the roller body 31 fitted into the flange body 33 rotates. As a result, the conveyor belt 11 wrapped around both rollers 21, 23 circulates in the counterclockwise direction in FIGS. 1 and 2. The outer surface of the conveyor belt 11 along the upper track becomes the conveying surface along which the medium is conveyed.

[0028] Next, the conveying plate 13 will be described with reference to Fig. 1 again. The conveying plate 13 contacts the inner peripheral surface (the surface behind the conveying surface) of the conveying belt 11 running on the upper track to support the conveying belt 11. When the conveying belt 11 runs, the inner peripheral surface of the conveying belt 11 slides along the upper surface of the conveying plate 13. The conveying plate 13 has a large number of through holes formed all over the surface, penetrating it in the thickness direction.

[0029] Next, the suction device 15 will be described. The suction device 15 is disposed in the hollow portion of the conveyor belt 11. When the suction device 15 is driven, air is sucked in through holes in the conveyor belt 11 and the conveyor plate 13, and the medium is attracted to the conveyor surface of the conveyor belt 11.

[0030] Next, the heating unit 5 will be described with reference to Fig. 1 again. The heating unit 5 is disposed above the transport unit 3, and includes two heater units 51 arranged side by side along the transport direction X1.

[0031] The heater unit 51 has a plurality of infrared heaters 53 arranged side by side in the conveying direction X1, a reflector 55 that reflects infrared rays radiated from each of the infrared heaters 53, and two fans 57. The plurality of infrared heaters 53 and the reflector 55 are housed in a casing 59 that is open at the bottom. The infrared rays radiated from the infrared heaters 53 are reflected by the reflector 55 and irradiated downward.

[0032] The two fans 57 are provided on the top surface of the casing 59. The fans 57 take in air outside the casing 59 and blow it out toward the inside of the casing 59 below.

[0033] The drying operation of the drying device 1 having the above configuration will be described. In the transport unit 3, the motor is driven to rotate the driving roller 21, and the transport belt 11 travels in a circular motion. At this time, the pins 19 at both ends of the transport belt 11 are inserted into the grooves 37 in the disk portions 33a of both the flange bodies 33 of the driving roller 21 and the driven roller 23, preventing the transport belt 11 from meandering.

[0034] Thereafter, the recording medium on which the image is formed by the inkjet method is conveyed to the conveying surface of the conveyor belt 11. Also, the suction device 15 is driven. As a result, as described above, air is sucked into the through holes of the conveyor belt 11 and the through holes of the conveyor plate 13, and a negative pressure is created above the conveying surface of the conveyor belt 11. Then, the recording medium is attracted to the conveying surface. In this way, the recording medium is conveyed along the conveying direction X1 while being attracted to the conveying surface.

[0035] Furthermore, the heated airflow generated by the heating unit 5 is blown onto the recording medium being transported by the transport belt 11, drying the image formed with ink. The transport unit 3 disposed below the heating unit 5 is also heated by the heated airflow. That is, the drive roller 21 and the driven roller 23 of the transport unit 3 are also heated.

[0036] As is clear from the above description, according to the drying device 1 of the present invention, each of the rollers 21, 23 is composed of a roller body 31 and a flange body 33, and the thermal expansion coefficient of the roller body 31 is higher than that of the flange body 33. Therefore, when the rollers 21, 23 are heated and the roller body 31 and the flange body 33 thermally expand, the amount of thermal expansion of the roller body 31 is greater than that of the flange body 33. In addition, in the fitting portion 39 between the roller body 31 and the flange body 33, the cylindrical portion 31b of the roller body 31 is fitted inside the cylindrical portion 33b of the flange body 33. Therefore, when the cylindrical portion 31b of the roller body 31 thermally expands radially outward in the fitting portion 39, the cylindrical portion 31b of the roller body 31 is pressed against the cylindrical portion 33b of the flange body 33 from the inside, and the cylindrical portions 31b, 33b are brought into closer contact with each other. This prevents the roller body 31 from rotating freely relative to the flange body 33.

[0037] In other words, when the flange body 33 is fitted into the roller body 31 by press fitting, depending on the relationship between the thermal expansion coefficients of the flange body 33 and the roller body 31, when the temperature of the rollers 21, 23 rises, the inner diameter of the part fitted on the outside may become larger than the outer diameter of the part fitted on the inside, causing the roller body 31 to spin freely relative to the flange body 33. In the present invention, the thermal expansion coefficient of the part fitted on the inside (cylindrical portion 31b of the roller body 31) is higher than the thermal expansion coefficient of the part fitted on the outside (cylindrical portion 33b of the flange body 33), so the above-mentioned spinning does not occur.

[0038] In addition, the roller body 31 is made of a material (aluminum in this example) that is relatively light and has small inertia during rotation, so the drive torque can be reduced. Furthermore, the flange body 33 is made of a material (SUS in this example) that is wear-resistant, so wear with the conveyor belt 11 during continuous operation can be reduced. The flange body 33 is preferably made of a material harder than the pins 19.

[0039] In addition, the fitting portion 39 may be configured so that the tubular portion 33b of the flange body 33 is fitted into the tubular portion 31b of the roller body 31. In this case, the portion of the fitting portion 39 that is fitted on the outside is the tubular portion 31b of the roller body 31, and the portion that is fitted on the inside is the tubular portion 33b of the flange body 33. In this case, the thermal expansion coefficient of the material of the flange body 33 is higher than that of the material of the roller body 31. However, as described above, when the materials of the roller body 31 and the flange body 33 are selected in consideration of reduction in driving torque and wear on the pins 19 of the conveyor belt 11, a configuration in which the tubular portion 31b of the roller body 31 is fitted into the tubular portion 33b of the flange body 33 as in the present invention is preferable.

[0040] Although the present invention has been described with respect to a specific embodiment, the present invention is not limited to the above embodiment. The above embodiment may be variously changed, substituted, or modified without departing from the scope and spirit of the present invention, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0041] 1 Drying device 11 Conveyor belt 21 Drive roller (roller) 23 Driven roller (roller) 31 Roller body 33 Flange body 37 Groove 39 Fitting part

Claims

1. A drying device that dries a medium on which an image is formed in a high-temperature environment while conveying the medium, an endless conveyor belt that supports the medium and conveys it in a predetermined conveying direction; a roller around which the conveyor belt is wound, The roller is A cylindrical roller body; and a flange body fitted to both ends of the roller body, A drying device, characterized in that a thermal expansion coefficient of a portion fitted on the inside of the fitting portion between the roller body and the flange body is higher than a thermal expansion coefficient of a portion fitted on the outside.

2. The roller body is fitted inside the flange body at the fitting portion, The drying device according to claim 1 , wherein the thermal expansion coefficient of the roller body is higher than the thermal expansion coefficient of the flange body.

3. 2. The drying device according to claim 1, wherein the flange body has a groove extending along a circumferential direction to prevent the conveyor belt from meandering.

Images