Drying device

Abstract

The invention provides a drying device. The drying device dries a medium on which an image is formed in a high-temperature environment while conveying the medium. The drying device is provided with an annular conveying belt and rollers. The conveyor belt supports the medium and conveys the medium in a predetermined conveying direction. The roller is wound by the conveyor belt. The roller has a cylindrical roller body and flange bodies fitted to both ends of the roller body. In a fitting portion of the roller body and the flange body, the thermal expansion coefficient of a portion that is fitted to the inside is higher than the thermal expansion coefficient of a portion that is fitted to the outside. Therefore, the roller body and the flange body can be embedded with each other without idling.

Description

Technical Field

[0001] The present invention relates to a drying device for drying a recording medium with an image formed thereon in a high-temperature environment while conveying the recording medium. Background Art

[0002] An image forming system including an inkjet image forming apparatus includes a drying device that dries an image formed on a recording medium by ink. The drying device may include a conveyor belt that is wound around a plurality of rollers and rotates by the rotation of the rollers. The recording medium supported by the conveyor belt is conveyed under a high temperature environment by the rotation of the conveyor belt, and the image formed by the ink is dried.

[0003] Generally, a roller is composed of a cylindrical roller body and flange bodies fitted to both end portions of the roller body.

[0004] In the above-mentioned drying device, the roller is generally made of metal. Considering the torsional strength, the roller body and the flange body are made of the same material. In order to prevent the conveyor belt from snaking (meandering), the flange body is sometimes formed with a groove along the circumferential direction. In addition, there is also a demand for making the roller body of a low-density material in order to reduce the driving torque.

[0005] However, when the roller body and the flange body are made of the same material, there is a problem that when a low-density material is selected, the groove for preventing meandering is easily worn, thereby reducing the durability of the meandering prevention effect. In addition, when the roller body and the flange body are made of different materials, as in the case where the flange body is made of a high-hardness material and the roller body is made of a low-density material, it is necessary to prevent the roller body from idling relative to the flange body. Therefore, it is necessary to perform a pinning operation for fixing the roller body and the flange body, which increases the number of manufacturing steps. Summary of the invention

[0006] Therefore, in view 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 with each other without idle rotation.

[0007] The drying device of the present invention dries the medium under a high temperature environment while conveying a medium with an image formed thereon. The drying device comprises an endless conveyor belt and a roller. The conveyor belt supports the medium and conveys the medium in a predetermined conveying direction. The roller is wound around the conveyor belt. The roller comprises a cylindrical roller body and flange bodies fitted at both ends of the roller body. In the fitting portion between the roller body and the flange body, the thermal expansion coefficient of the portion fitted inside is higher than the thermal expansion coefficient of the portion fitted outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1This is a front view schematically showing the interior of a drying device according to an embodiment of the present invention.

[0009] Figure 2 It is a perspective view showing a conveying unit (illustration of the conveyor belt is omitted) in the drying device according to one embodiment of the present invention.

[0010] Figure 3 It is a perspective view showing a driving roller of a conveying unit in a drying device according to an embodiment of the present invention.

[0011] Figure 4 It is a cross-sectional view showing a driving roller in a drying device according to an embodiment of the present invention.

[0012] Figure 5A This is a cross-sectional view showing one end portion of a driving roller in a drying device according to an embodiment of the present invention.

[0013] Figure 5B This is a cross-sectional view showing one end portion of a driving roller around which a conveyor belt is wound in a drying device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] Next, refer to the attached Figure 1 A drying device according to an embodiment of the present invention will be described.

[0015] Reference Figure 1 The overall structure of the drying device 1 will be described. Figure 1 It is a front view schematically showing the inside of the drying device 1. Fr, Rr, L, and R shown in each figure respectively represent the front side, the rear side, the left side, and the right side of the drying device 1.

[0016] The drying device 1 comprises a conveying unit 3 and a heating unit 5, wherein the conveying unit 3 is arranged along a conveying direction X1 (from Figure 1 The heating unit 5 transports a medium (a cut sheet, a long sheet, etc.) on which an image is formed by an inkjet method (in a right-to-left direction), and the heating unit 5 dries the medium transported by the transport unit 3.

[0017] First, refer to Figure 1 and Figure 2 The transport unit 3 will be described. Figure 2 2 is a perspective view showing the conveying unit 3 (the conveying belt 11 is omitted). Figure 1 and Figure 2 As shown, the conveying unit 3 includes a conveyor belt 11 for conveying a medium, a conveyor plate 13 for supporting the conveyor belt 11, a suction device 15 for adsorbing the medium to the conveyor belt 11, and front and rear side plates 17 supporting these (see FIG. Figure 2 ).

[0018] First, the conveyor belt 11 will be described. The conveyor belt 11 is an endless conveyor belt, and a plurality of through holes are formed on the entire surface thereof and penetrate in the thickness direction. Pins 19 (see FIG. 1 ) are fixed at predetermined intervals in the circumferential direction at both ends of the conveyor belt 11 in the width direction X2 (a direction orthogonal to the conveying direction X1). Figure 5B The pin 19 has a disc-shaped head 19a and a hemispherical top end 19b, and the head 19a is fixed in such a way as to clamp the conveyor belt 11 from the outside and the inside. The top end 19b of the pin 19 protrudes inward from the inner circumference of the conveyor belt 11. Figure 1 As shown, the conveyor belt 11 is wound around a driving roller 21 and a driven roller 23 .

[0019] Next, refer to Figure 3 , Figure 4 , Figure 5A and Figure 5B The driving roller 21 and the driven roller 23 will be described. 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, Figure 5A and Figure 5B 2 is a cross-sectional view showing one end portion of the driving roller 21. Here, the driving roller 21 will be mainly described, but the driven roller 23 also has the same structure as that of the driving roller 21.

[0020] like Figure 3 and Figure 4 As shown, the driving roller 21 includes a roller body 31 , flange bodies 33 fitted to both end portions of the roller body 31 , and a rotating shaft 35 .

[0021] First, the roller body 31 will be described. Figure 4 As shown in the figure, the roller body 31 is formed into a cylindrical shape with a certain inner diameter, and has a main body 31a and a barrel 31b, wherein the main body 31a has a predetermined outer diameter, and the barrel 31b is vertically arranged on the end surface of the main body 31a along the inner circumference. That is, the outer diameter of the barrel 31b is smaller than the outer diameter of the main body 31a, and the inner diameter is equal to the inner diameter of the main body 31a. In order to reduce the driving torque, the roller body 31 is made of a light material (such as aluminum) that can reduce the inertia during rotation.

[0022] Next, the flange body 33 will be described. Figure 4As shown, the flange body 33 has a circular plate portion 33a and a cylindrical portion 33b, wherein the circular plate portion 33a has a certain thickness, and the cylindrical portion 33b is vertically arranged on one end surface of the circular plate portion 33a along the outer circumference. The outer diameter of the cylindrical 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 cylindrical portion 31b of the roller body 31. In addition, the length of the cylindrical portion 33b of the flange body 33 is slightly longer than the length of the cylindrical portion 31b of the roller body 31. A through hole 33c is opened in the center of the circular plate portion 33a.

[0023] The flange body 33 is made of a material (such as SUS (stainless steel)) with a smaller thermal expansion coefficient than the roller body 31 and having wear resistance. For example, when the roller body 31 is made of aluminum, the thermal expansion coefficient is 23.5 (×10 -6 / ℃), when the flange body 33 is made of SUS304 (304 stainless steel), the thermal expansion coefficient is 19.3 (×10 -6 / ℃).

[0024] like Figure 5A As shown, a groove 37 is formed along the circumferential direction on the outer peripheral surface of the circular plate portion 33a. The groove 37 has a shallow portion 37a and a deep portion 37b, wherein the shallow portion 37a has a wide width (length along the length direction of the roller 21) and a shallow depth, and the deep portion 37b is provided at the center of the shallow portion 37a, and has a narrower width than the shallow portion 37a and a deeper depth.

[0025] like Figure 5A and Figure 5B As shown, the two cylinders 31b of the roller body 31 are respectively embedded in the cylinder 33b of the roller body 33. In the interlocking portion 39 of the two, the portion embedded on the outside is the cylinder 33b of the flange body 33, and the portion embedded on the inside is the cylinder 31b of the roller body 31. The inner surface of the cylinder 33b of the flange body 33 contacts the outer surface of the cylinder 31b of the roller body 31, and the end surface of the cylinder 33b of the flange body 33 contacts the end surface of the main body 31a of the roller body 31. In addition, the inner surface of the circular plate portion 33a of the flange body 33 does not contact the end surface of the cylinder 31b of the roller body 31, and a predetermined gap is spaced between the two surfaces.

[0026] In addition, if Figure 5B As shown, the pins 19 fixed to the two ends of the conveyor belt 11 enter the grooves 37 of the circular plate portions 33a of the two flange bodies 33. Specifically, a portion of the head portion 19a of the pin 19 (the portion protruding from the inner surface of the conveyor belt 11) enters the shallow portion 37a of the groove 37, and the top end portion 19b of the pin 19 enters the deep portion 37b of the groove 37.

[0027] Next, the rotating shaft 35 will be described. The rotating shaft 35 is inserted into the through hole 33c of the circular plate portion 33a of the two flange bodies 33. Figure 4As shown, the rotating shaft 35 is fixed to one (in this example, the front) flange body 33 so as to be integrally 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.

[0028] A driving gear (not shown) is fixed to one end of the rotating shaft 35 of the driving roller 21. The driving gear is connected to a motor (not shown) through a gear train. When the motor is driven and the driving gear is rotated through the gear train, the rotating shaft 35 rotates together with the driving gear. Then, the flange body 33 rotates together with the rotating shaft 35, and the roller body 31 embedded in the flange body 33 rotates. As a result, the conveyor belt 11 wound around the two rollers 21 and 23 is rotated. Figure 1 and Figure 2 The outer surface of the conveyor belt 11 along the upper track becomes the conveying surface of the conveying medium.

[0029] Next, refer again to Figure 1 , the conveyor plate 13 is described. The conveyor plate 13 contacts the inner peripheral surface (the surface inside the conveying surface) of the conveyor belt 11 running along the upper track and supports the conveyor belt 11. When the conveyor belt 11 runs, the inner peripheral surface of the conveyor belt 11 slides along the upper surface of the conveyor plate 13. The conveyor plate 13 is formed with a plurality of through holes that penetrate the entire surface in the thickness direction.

[0030] Next, the suction device 15 will be described. The suction device 15 is disposed in the hollow portion of the conveyor belt 11. By driving the suction device 15, air is sucked out of the through holes of the conveyor belt 11 and the through holes of the conveyor plate 13, so that the medium is sucked onto the conveying surface of the conveyor belt 11.

[0031] Next, refer again to Figure 1 Next, the heating unit 5 will be described. The heating unit 5 is disposed above the conveying unit 3 and includes two heater units 51 arranged along the conveying direction X1.

[0032] The heater unit 51 includes a plurality of infrared heaters 53, a reflector 55, and two fans 57, wherein the plurality of infrared heaters 53 are arranged to be arranged along the conveying direction X1, and the reflector 55 reflects the infrared rays emitted from each infrared heater 53. The plurality of infrared heaters 53 and the reflector 55 are accommodated in a housing 59 having an opening on the lower surface. The infrared rays emitted from the infrared heaters 53 are reflected by the reflector 55 and irradiated downward.

[0033] Two fans 57 are provided on the top surface of the housing 59. The fans 57 suck air from outside the housing 59 and blow it toward the inside of the housing 59 below.

[0034] The drying operation of the drying device 1 having the above structure will be described. In the conveying unit 3, the driving motor rotates the driving roller 21, and the conveyor belt 11 circulates. At this time, since the pins 19 at both ends of the conveyor belt 11 enter the grooves 37 of the circular plate portions 33a of the flange bodies 33 of the driving roller 21 and the driven roller 23, the conveyor belt 11 is prevented from meandering.

[0035] After that, the recording medium on which the image is formed by the inkjet method is conveyed to the conveying surface of the conveyor belt 11. In addition, the suction device 15 is driven. As described above, the air in the through holes of the conveyor belt 11 and the through holes of the conveyor plate 13 is sucked out, and the upper part of the conveying surface of the conveyor belt 11 becomes negative pressure. As a result, the recording medium is adsorbed to the conveying surface. In this way, the recording medium is conveyed along the conveying direction X1 while being adsorbed to the conveying surface.

[0036] The heated airflow generated by the heating unit 5 is blown to the recording medium conveyed by the conveyor belt 11, thereby drying the image formed by the ink. In addition, the conveying unit 3 disposed below the heating unit 5 is also heated by the heated airflow. That is, the driving roller 21 and the driven roller 23 of the conveying unit 3 are also heated.

[0037] As can be seen from the above description, according to the drying device 1 of the present invention, the two rollers 21 and 23 are respectively composed of the roller body 31 and the 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 and 23 are heated and the roller body 31 and the flange body 33 are respectively thermally expanded, the thermal expansion amount of the roller body 31 is larger than the thermal expansion amount 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 embedded inside the cylindrical portion 33b of the flange body 33. Therefore, in the fitting portion 39, when the cylindrical portion 31b of the roller body 31 thermally expands radially outward, the cylindrical portion 31b of the roller body 31 pushes the cylindrical portion 33b of the flange body 33 from the inside, so that the two cylindrical portions 31b and 33b are in closer contact. According to this, it is possible to prevent the roller body 31 from idling relative to the flange body 33.

[0038] That is, when the flange body 33 is fitted to the roller body 31 by press-fitting, due to the relationship between the thermal expansion coefficients of the flange body 33 and the roller body 31, when the temperature of the rollers 21 and 23 rises, the inner diameter of the portion fitted on the outside is sometimes larger than the outer diameter of the portion fitted on the inside, and the roller body 31 rotates idly relative to the flange body 33. In the present invention, since the thermal expansion coefficient of the portion fitted on the inside (the barrel portion 31b of the roller body 31) is higher than the thermal expansion coefficient of the portion fitted on the outside (the barrel portion 33b of the flange body 33), the above-mentioned idling does not occur.

[0039] In addition, since the roller body 31 is made of a material that is light and can reduce inertia during rotation (aluminum in this example), the driving torque can be reduced. Furthermore, since the flange body 33 is made of a wear-resistant material (SUS (stainless steel) in this example), the wear with the conveyor belt 11 during continuous operation can be reduced. The material of the flange body 33 is preferably made of a material with a higher hardness than the pin 19.

[0040] Furthermore, in the fitting portion 39, the cylindrical portion 33b of the flange body 33 may be configured to be embedded in the cylindrical portion 31b of the roller body 31. In this case, in the fitting portion 39, the portion that is embedded on the outside is the cylindrical portion 31b of the roller body 31, and the portion that is embedded on the inside is the cylindrical 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 the thermal expansion coefficient 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 reducing the driving torque and the wear on the pin 19 of the conveyor belt 11, it is preferable to have a structure in which the cylindrical portion 31b of the roller body 31 is embedded in the cylindrical portion 33b of the flange body 33 as in the present invention.

[0041] The present invention describes specific embodiments, but the present invention is not limited to the above embodiments. The above embodiments can be variously changed, replaced, and deformed without departing from the scope and spirit of the present invention, and the technical solution covers all embodiments that can be included in the scope of the technical idea.

Claims

1. A drying device, which dries a medium with an image formed thereon under a high temperature environment while conveying the medium, characterized in that: The invention comprises: an endless conveyor belt which supports the medium and conveys the medium in a predetermined conveying direction; and a roller which is wound around the conveyor belt. The roller comprises: a cylindrical roller body; and flange bodies fitted at both ends of the roller body. In the fitting portion between the roller body and the flange body, a portion fitted on the inner side has a higher thermal expansion coefficient than a portion fitted on the outer side.

2. The drying device according to claim 1, characterized in that: In the fitting portion, the roller body is fitted inside the flange body. The roller body has a higher thermal expansion coefficient than the flange body.

3. The drying device according to claim 1, characterized in that: The flange body has a groove along the circumferential direction to prevent the conveyor belt from meandering.

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