JP5760907B2 - Heating apparatus and heating method - Google Patents

Description

  The present invention relates to a heating apparatus and a heating method used when a paint is applied to the outer peripheral surface of a cylindrical or endless belt-like object to be heated and then cured to form a coating film, and in particular, fixing of an image forming apparatus. The present invention relates to a heating apparatus and a heating method suitable for curing a coating film when various layers are formed on the surface of a fixing roller or a fixing belt in the apparatus.

  2. Description of the Related Art In recent years, electrophotographic image forming apparatuses have been made color and energy-saving. Along with this, a fixing unit used in a fixing process for fusing toner by heat while pinching and pressing a sheet is fixed on a roller. The structure has changed greatly from the system to the belt system.

  Also, recently, as a so-called production printing business, the range of application of image forming devices using the principle of electrophotography has expanded to the high-speed printing area that was previously supported by printing presses. The endless belt also has a diameter of about doubled from a conventional inner diameter of 50 to 75 mmφ (referring to an inner diameter equivalent to a circle; hereinafter the same applies to an endless belt) to a diameter of 145 mmφ or more. A wide variety of inner diameter variations are increasing.

  An endless belt used in this fixing process is formed with an elastic layer (about 100 to 300 μm) made of heat-resistant rubber (silicone rubber, etc.) and then a primer (adhesive) is applied to the release layer (fluororesin etc. ) Is generally used, and a fixing belt having a structure with a thickness of about 20 to 30 μm is used.

  Conventionally, as a method for forming the elastic layer, a method of coating liquid silicone rubber by spray coating or dip coating (dipping method) has been generally used. The elastic layer made of silicone rubber is formed as a film by changing from a liquid state to a solid state by being vulcanized by being heated in a heating device at a temperature of about 100 to 150 ° C. after being coated by the above method. It is common. Usually, the above heating process is called a primary vulcanization process, and conventionally, a heating method mainly using a hot stove has been used.

  When a cylindrical object to be heated is heated using a so-called safe furnace type hot air oven (heating device), as shown in FIG. 11, the holder 31 is placed with the central axis of the object to be heated 35 directed vertically. In general, heating is performed by a batch method in which a number of these are held in a furnace (only one is shown in FIG. 11) and heated (fired). When vulcanizing liquid silicone rubber coated on the outer peripheral surface of the endless belt-like fixing part by heating in such a batch system, sagging occurs at the top or end of the coating film, resulting in film thickness disturbance. Cheap.

  It is conceivable that the hot air is set at a high temperature and heated rapidly so that the liquid silicone rubber does not drip before curing. However, when heated at a high temperature, air is volatilized from the liquid silicone rubber and becomes bubbles. This is not preferable because it tends to rupture and easily generate pinhole-like defects on the surface of the elastic layer.

  In a fixing component used in a fixing process of an image forming apparatus, such a defect becomes defective even if the pinhole diameter is about 0.1 mmφ and cannot be repaired later (it is difficult to fill the pinhole). Therefore, it becomes a cause of reducing the yield rate at the time of manufacture.

  In order to solve the above problems (coating dripping and appearance defects), a method of applying heat while rotating the object to be heated while holding the cylindrical central axis horizontally with a holder is considered. It is done. In this case, instead of processing the heated object in batch using the safe furnace type hot air furnace as introduced above, continuous hot air capable of continuous heating combining the hot air furnace and the conveying device of the heated object. A furnace can also be used. In a hot stove, when batch processing is performed, heat leaks to the outside each time, and it takes time to return the inside of the furnace to a predetermined temperature. Efficiency and energy efficiency are reduced. Therefore, in the above-described method in which heat is applied while rotating while holding the central axis of the cylindrical shape, it is desirable to use a continuous hot stove in consideration of these efficiencies.

  However, because it is a continuous furnace, depending on the heating time, the furnace length tends to be as long as 3 to 6 m, and the inlet and outlet of the object to be heated are separated from each other and installed in the mass production line. It is necessary to keep the inside of the furnace warm with hot air. For example, preheating is required for about 1 hour before heat treatment, and the temperature of the hot air in the heating furnace needs to be maintained during the break time of workers such as lunch breaks, resulting in a disadvantage that power consumption increases.

  In order to avoid these drawbacks, it is conceivable to use heating by infrared rays as shown in Patent Document 1 instead of the heating method using a hot stove. In the case of heating by infrared rays, it is sufficient to supply electricity to a heating source (heater) when heating, and energy consumption does not increase as described above.

  Specifically, for example, as shown in FIG. 12, a heated object 45 set on a holder 41 made of cylindrical metal is put into a heating device together with the holder 41, and liquid silicone coated on the outer periphery. The heated object 45 is continuously rotated at a rotational speed of several to several tens of rpm (rotations / minute) so that the rubber does not drip. Then, the liquid silicone rubber on the surface of the heated object 45 is heated and cured by the halogen heater 42 disposed in the vicinity of the heated object 45 and the reflection plate 43 disposed behind the halogen heater 42.

  In such a system, since the liquid silicone rubber does not easily sag, it is not necessary to increase the heating temperature, and the coating film can be cured without causing appearance defects such as pinholes.

  However, when heating an object to be heated having a cylindrical shape or an endless belt shape, as shown in FIG. 12, it is common to insert a core made of a cylindrical metal to form the holder 41. However, it is difficult for the holder 41 to normally hold the inner surface of the object to be heated 45 in close contact with each other without a slight gap, and when the core is actually heated as the holder 42, the holder 41 is in close contact. A slight temperature difference occurs at a place where it is not, and heating unevenness appears on the surface of the object to be heated 45 as streaks after heat curing.

  Naturally, when such a streak is used as a fixing part of an image forming apparatus, it appears in the output image, which is not preferable. In addition, when heating an endless belt-like object to be heated having a small heat capacity, a holding tool having a large heat capacity is inserted into the core, which is not preferable from the viewpoint of energy saving.

  In this way, in any process or equipment that is heated to apply liquid silicone rubber to a cylindrical or endless belt-like object to be cured and cured (vulcanized), appearance defects occur and energy is saved in any method. There is a problem from either point of view, etc., and all of them are not satisfied at present.

  The above problem is not only when the elastic layer such as silicone rubber is formed on the outer peripheral surface of the fixing component, but also when heating and curing a cylindrical or endless belt-shaped object having a coating applied on the outer peripheral surface. This is true for all the heating devices used.

  Therefore, the present invention suppresses the occurrence of coating defects, pinholes, streaks, and other appearance defects when heating or curing a cylindrical or endless belt-shaped object whose outer peripheral surface is coated with paint. It is an object of the present invention to provide a heating apparatus and a heating method that can save energy.

  The above-mentioned subject is achieved by the present invention shown below.

  The invention described in claim 1 is a heating in which a support member that supports a cylindrical or endless belt-shaped object to be heated from the inside and a heating unit that applies heat to the object to be heated are arranged in a housing. In the apparatus, the support member is composed of a plurality of rod-like bodies that are forested in parallel in a substantially horizontal direction, and the plurality of rod-like bodies are arranged on one circumference when viewed from the longitudinal direction. When the object to be heated is suspended so that all of the plurality of rod-shaped bodies are located inside the object to be heated, the lowermost part of the object to be heated is always separated from the rod-shaped body. In addition, the heating apparatus is provided with a rotating unit that rotates the support member so that the plurality of rod-shaped bodies move on the circumference.

  In the first aspect of the present invention, the object to be heated is hung so that all of the plurality of rod-shaped bodies are located inside the object to be heated, and the support member is rotated by the rotating means. When the object to be heated is heated by the heating means, the object to be heated is suspended below the support member (the plurality of rod-shaped bodies), and the object to be heated also rotates as the support member rotates. Then, the part suspended from the rod-shaped body moves with the rotation.

  Therefore, according to the first aspect of the present invention, since the object to be heated is heated while being rotated, it is possible to suppress the occurrence of coating film dripping and pinholes. Further, since the object to be heated is supported in a state where the lowermost part is suspended without being stretched over the plurality of rod-shaped bodies, the contact point between the object to be heated and the rod-shaped body that supports the object is Since the support member is moved by the rotation of the support member, it is possible to suppress the occurrence of uneven stripes. Furthermore, the support member that supports the object to be heated is composed of a plurality of rod-shaped bodies, and only the rod-shaped body is in linear contact with the inner peripheral surface of the object to be heated, so that, for example, a cylindrical shape Compared with the case where a core is used as a support member, the heat capacity of the support member is greatly reduced, and energy can be saved.

It is front sectional drawing which shows the heating apparatus of embodiment which is an illustrative aspect of this invention. It is a right side sectional view (BB sectional view) of the heating device of the embodiment shown in FIG. It is the enlarged front view which extracted only a part of supporting member in FIG. It is CC sectional drawing in FIG. It is an expanded sectional view equivalent to CC section in Drawing 3 which extracted only a support member and a thing to be heated in Drawing 1 and Drawing 2. It is an expanded sectional view showing the modification at the time of changing the to-be-heated material in FIG. 5 from an endless belt body to a cylindrical body. It is the right side sectional view (BB sectional view) which extracted the supporting member and heating means peripheral part in FIG. FIG. 2 is a schematic enlarged cross-sectional view showing an example of a fixing belt obtained by the heating device of the embodiment shown in FIG. 1. It is a graph which shows transition of the temperature change of the silicone rubber layer surface formed in the outer peripheral surface of the endless belt body at the time of a heating in the verification test using the heating apparatus of embodiment shown in FIG. In the verification test using the heating device of the embodiment shown in FIG. 1, the temperature of the surface of the silicone rubber layer formed on the outer peripheral surface of the endless belt body when the temperature reaches the set temperature is defined as the rotational axis direction of the endless belt body. The result of measuring three points in the parallel direction is shown. It is a schematic block diagram which shows typically the conventional safe furnace type hot-air type heating apparatus. It is a schematic block diagram which shows typically the heating apparatus heated with an infrared heater, rotating a to-be-heated material with the conventional safe furnace type.

  Hereinafter, the heating device and the endless belt member of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front sectional view showing a heating apparatus according to an embodiment which is an exemplary aspect of the present invention, and FIG. 2 is a sectional view from the right side. Specifically, FIG. 1 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 2 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 1 and 2, the heating device of this embodiment includes a holder (support member) 1 as a jig that supports an endless belt body 5 that is an object to be heated from the inside in a housing 30. And a halogen heater (heating means) 12 for applying heat to the endless belt body 5.

  The holder 1 includes an axis 7, a skeleton member (rod-like body) 8, a large holding plate 9a, and a small holding plate 9b. The skeletal material 8 is manufactured by bending a metal such as a stainless steel (SUS) pipe having a diameter of about 6 mmφ and winding a resin adhesive tape having heat resistance.

  FIG. 3 shows an enlarged front view in which only the skeleton member 8 and the holding plate small 9b in the holder 1 in FIG. 1 are extracted. Moreover, CC sectional drawing in FIG. 3 is shown in FIG.

  As shown in FIG. 4, the holder 1 has twelve skeleton members 8 arranged at equal intervals so as to be positioned on a circle D coaxial with the axis 7, as shown in FIG. 3. In addition, it is constructed with forests in the horizontal direction.

  One end of the skeleton member 8 is bent toward the axis 7 by bending, and the circle drawn by the edge becomes smaller in diameter than the circle D, and is connected to the tip of the axis 7 around the center. The disc-shaped holding plate small 9b is attached. The other end of the skeleton member 8 is attached as it is to a large disc-shaped holding plate 9 a connected to the middle of the shaft center 7.

  Accordingly, the twelve skeleton members 8 rotate so as to move on the circumference of the circle D as the axis 7 rotates.

  As shown in FIG. 2, an endless belt body 5 that is an object to be heated is hung on the skeletal material 8 that is forested. FIG. 5 shows an enlarged cross-sectional view at a position corresponding to the CC cross section in FIG. 3 in which only the holder 1 and the endless belt body 5 in FIGS. 1 and 2 are extracted. As shown in FIG. 5, the endless belt body 5 is hung so that all of the twelve skeleton members 8 are located inside the endless belt body 5. At this time, the lowermost portion of the endless belt body 5 is separated from the frame material 8. When the holder 1 rotates and the twelve skeleton members 8 move on the circumference of the circle D, the endless belt body 5 also rotates along with it, but the endless belt body 5 whose inner peripheral length is longer than the circle D is The lowermost part is always separated from the skeleton 8.

  FIG. 6 is a modified example in which a cylindrical body 5 ′ whose inner peripheral length is longer than the circle D is used instead of the endless belt body 5, and is an enlarged cross-sectional view from the same position as in FIG. 5. Even in the case of the cylindrical body 5 ′, as in the case of the endless belt body 5, all the 12 skeleton members 8 are hung so as to be located inside the cylindrical body 5 ′, and the lowermost part is the skeleton member. 8 is always spaced apart.

  The shaft center 7 further extends from a portion where the holding plate large 9 a is connected, and the vicinity of the end portion is fitted into the rotating shaft 10. The rotating shaft 10 has a cylindrical structure, the shaft center 7 passes through the rotating shaft 10, and both are fixed by a thumbscrew 6. Since the rotary shaft 10 and the shaft center 7 can be detached with the thumbscrew 6, holders of various diameters (the diameter of the circle D in the present embodiment) are prepared, and at the time of changeover By selecting and replacing a holder having an appropriate diameter corresponding to the inner diameter of the object to be heated (endless belt body 5 in the present embodiment), the object to be heated having various inner diameters can be handled.

  A ring-shaped pulley 11 b is attached to the rotating shaft 10. On the outer periphery of the pulley 11b, a timing belt 11c is stretched between the pulley 11a and the outer periphery of the pulley 11a attached to the shaft of the motor 11, and the rotational force of the motor 11 is retained via the rotating shaft 10 and the like. To be communicated to.

  As shown in FIG. 2, the halogen heater 12 that is a heating means is arranged at a position spaced apart from the outer peripheral surface of the endless belt body 5 hung on the skeleton member 8 at the left and right in the axial direction of the shaft center 7. Arranged individually. The halogen heater 12 is a kind of radiation-type infrared heater that emits infrared rays. In the present embodiment, the halogen heater 12 uses an infrared waveband having a wavelength of about 0.7 to 2 μm. .

  In the present invention, the infrared heater is not limited to the halogen heater of the present embodiment, and for example, a known radiant infrared heater such as a carbon heater or a ceramic heater can be used.

  FIG. 7 is a cross-sectional view taken along the line BB in FIG. 1 in which the periphery of the holder 1 and the halogen heater 12 is extracted. As shown in FIG. 7, a reflecting plate 13 whose surface is made of bright aluminum is disposed on the back surface of the halogen heater 12 toward the holder 1. As can be seen from FIG. 7, the reflector 13 is processed into a parabolic shape, and the halogen heater 12 is disposed on the side where the focal point is formed.

  The halogen heater 12 and the reflection plate 13 have an integral structure, and can be moved back and forth with respect to the outer peripheral surface of the endless belt body 5 by a moving mechanism described later. Therefore, when heat-treating another object to be heated instead of the endless belt body 5, the distance between the halogen heater 12 and the object to be heated can be set according to the size.

  The moving mechanism includes a guide shaft 14a, a sliding screw 14b, a transmission shaft 14c, and a knob 14d. When the user rotates the knob 14d, the rotation is transmitted to the sliding screw 14b through the transmission shaft 14c, and the halogen heater 12 and the reflecting plate 13 are integrally movable along the guide shaft 14a by the rotation. It has become. Therefore, even when the circumference of the object to be heated changes, the distance between the halogen heater 12 and the object to be heated can be set appropriately. The position at that time is detected by the sensor 14e, and it is possible to always heat at a fixed position.

  A radiation thermometer 15 is installed below the endless belt body 5 to measure the temperature of the outer peripheral surface of the endless belt body 5. The measurement result is sent as a signal to a control means (not shown), and the voltage controlled by PID control (P: proportional control, I: integral control, D: derivative control) based on the value is used as the halogen heater 12. Is feedback controlled to be applied to By this feedback control, the endless belt body 5 is maintained at a desired temperature. At this time, a front viewing tube 15 a is attached so that infrared radiation emitted from the halogen heater 12 is not directly detected by the radiation thermometer 15. Therefore, it is possible to sense only the infrared rays emitted from the endless belt body 5 and accurately heat the outer peripheral surface of the endless belt body 5 at a desired temperature.

  The holder 1 and the heating mechanism (halogen heater 12, reflector 13 and the like) described above are installed in a closed space surrounded by the heat insulating plate 16 from any direction. The casing 30 is provided with an exhaust port 17 for exhausting the gas generated when the object to be heated such as the endless belt body 5 is heated in the closed space surrounded by the heat insulating plate 16 from the closed space. Has been.

  The heating device according to the present embodiment has a structure in which an object to be heated such as the endless belt body 5 is heated with the inside of a closed space surrounded by the heat insulating plate 16 in the six directions of front, rear, left, right, and upper as the interior. The outside of the closed space is covered with protective plates 16b and 16c for safety, so that an operator directly touches the heat insulating plate 16 heated to a temperature close to the furnace temperature so as not to suffer injury such as burns. Consideration.

  In the closed space, the upper heat insulating plate 16a, which is a part of the heat insulating plate 16, has a structure that can be opened and closed in the direction indicated by the arrow X in FIG. When an object to be heated such as the endless belt body 5 is put in and out of the furnace, the rotation of the motor 19 is transmitted to the fulcrum shaft 18 through the gear 19a, thereby opening and closing the door comprising the upper heat insulating plate 16a and the upper protective plate 16c. Can be opened and closed. When the door is opened, the holder 1 and the motor 11 and the mechanical components (11a to 11c) that transmit the rotation are indicated by broken lines in FIG. 1 (partially omitted from the broken lines). ), All are tilted. A counterweight 20 having a weight that can be balanced with the upper heat insulating plate 16a and the upper protective plate 16c is attached to the side where the vertical position of the opening / closing door is lowered so that the opening / closing operation smoothly operates. .

  A sensor 21 for detecting a human hand is arranged at the upper part of the apparatus so that the open / close door composed of the upper heat insulating plate 16a and the upper protective plate 16c does not open and close when an object to be heated such as the endless belt 5 is taken in and out. is set up. When the sensor 21 detects a human hand, even if the heating operation is erroneously started when the endless belt body 5 is put in and out, an error occurs, and the opening / closing mechanism of the opening / closing door is not activated.

  In addition, the loading / unloading of the heated object such as the endless belt body 5 is sensed by the work detection sensor 23, and the device does not operate even if the start button 22 is pressed in a state where the endless belt body 5 is not set. It is prevented that the furnace is heated (empty) while it is empty.

  The housing 30 is composed of a structural material 24, and a metal cover 25 is attached to the structural material 24, and everything except the range where the sensor 21 is effective is covered with the metal cover 25. Also, maintenance doors 26a and 26b are provided in a part of the metal cover 25, and the maintenance doors 26a and 26b can be opened to access the inside of the apparatus during maintenance of the apparatus.

  The present invention discloses a heating apparatus suitable for heating and curing a paint applied directly to the surface of a cylindrical or endless belt-like substrate or via another layer. In the present embodiment, In particular, an endless belt body 5 whose surface is coated with liquid silicone rubber is used as an object to be heated. The endless belt body 5 in this embodiment is an endless belt body that is finally used as a fixing belt.

  FIG. 8 shows a schematic enlarged cross-sectional view of a fixing belt obtained by heating and curing a silicone rubber layer by the heating device of this embodiment. As shown in FIG. 8, in the fixing belt, a silicone rubber layer 5b is formed on a surface (outer peripheral surface) of a base material 5a via a primer layer (adhesive layer) 5d, and further a primer layer (adhesive layer) 5d ′. A release layer 5c is formed through the end, and an endless belt-like object in which both omitted ends are connected to form an annular shape.

  The material of the base material 5a is a resin, specifically, a polyimide resin or a polyamide-imide resin may be mentioned as a suitable material. Usually, the base material 5a is molded into an endless belt with a thickness of about 50 to 90 μm by stretch molding.

  The silicone rubber layer 5b is a layer that functions as an elastic layer, and is formed by applying liquid silicone rubber as described above and curing it by heating and vulcanizing. The thickness of the silicone rubber layer 5b is usually selected from the range of about 100 to 300 μm.

  The release layer 5c is a layer made of a fluororesin (PFA, PTFE, etc.) having a thickness of about 15 to 25 μm.

  The primer layers 5d and 5d 'are layers having adhesiveness with a thickness of about several micrometers. In order to improve adhesiveness, it is interposed between each layer (base material 5a, silicone rubber layer 5b, release layer 5c) having each function.

  Each of these layers is laminated | stacked on the surface (outer peripheral surface) of the base material 5a by coating in the order which should be laminated | stacked, and repeating a heating. Each of these layers can be applied using, for example, a coating film forming apparatus described in Patent Document 2 or a conventional coating apparatus such as a spray coating method or a dipping coating method.

  Next, the operation of the heating device of the present embodiment (the embodiment of the heating method of the present invention) will be described.

  First, before the heat treatment, the heating apparatus is in a state where the open / close door composed of the upper heat insulating plate 16a and the upper protective plate 16c is opened, and the holder 1 is also at the same angle as shown by a broken line in FIG. It has become. Here, one end of the endless belt body 5 is gripped from the inner peripheral surface side by a gripping jig (not shown), and the endless belt body 5 is inserted into the holder 1 from the other end along the skeleton material 8 ( (Arrow Y direction 2 in the figure). When the gripping of the gripping jig is released, the endless belt body 5 slightly falls along the skeleton material 8 and hits the holding plate 9a. At that time, the endless belt body 5 is detected by the workpiece detection sensor 23.

  Incidentally, since the coating film is formed on the outer peripheral surface of the endless belt body 5 by a spray coating method, a dipping coating method, or the like before the heat treatment by the present heating device, the outer peripheral surface cannot be touched. Therefore, when the endless belt body 5 is set in the heating device as described above, the work is performed in a state of being gripped from the inner peripheral surface by another gripping jig.

  As described above, when the start button 22 of the present heating device is pushed with the endless belt body 5 set on the holder 1, the motor 19 that rotates the fulcrum shaft 18 is activated, and the upper heat insulating plate 16a and the upper protective plate 16c. A closed space is created in which the open / close door is closed and is surrounded by the heat insulating plate 16, and is in a state shown by a solid line in FIG.

  At this time, as shown in FIG. 5, the endless belt body 5 is supported by the upper portion of the endless belt body 5 in contact with the endless belt body 5 because the circle D in which the frame material 8 is positioned is smaller than the inner diameter of the endless belt body 5. , The lower part will hang down. The shape at this time depends on the rigidity of the endless belt body 5. When the rigidity is lost by its own weight, the endless belt body 5 is in a suspended state. Shape). In either case, only the upper part comes into contact with the skeleton material 8.

  As described above, the endless belt body 5 is suspended from the holder (support member) 1 so that all of the plurality of skeleton members (rod-like bodies) 8 are located inside the endless belt body (object to be heated) 5. Thus, the setting of the endless belt body 5 to the heating device is completed (the “hanging process”).

  At this time, the skeleton material 8 of the holder 1 is not completely horizontal, and it is desirable to provide an angle so that the insertion side of the endless belt body 5 is inclined to the side away from the ground. By setting the angle in this way, it is possible to reduce the possibility that the endless belt body 5 is displaced or dropped from the holder 1 when the holder 1 is rotated in the operation of the next step. In the present invention, the “substantially horizontal direction” is a concept including a case where a slight angle is given from a completely horizontal state as described above, and specifically selected from a range of about 0 to 10 °. As described above, it is more preferable that the range is about 2 to 5 °.

  In the present heating apparatus, the operation of the heating process is automatically started from the state where the endless belt body 5 is set as described above. After the open / close door composed of the upper heat insulating plate 16 a and the upper protective plate 16 c is closed, the motor 11 rotates and the rotational driving force is transmitted to the holder 1 through the rotary shaft 10. The holder 1 rotates in a direction indicated by an arrow Z in FIG. 2 at a predetermined number of rotations, and the rotation is transmitted to the endless belt body 5 through the skeleton member 8 so that the endless belt body 5 rotates.

  Next, the halogen heater 12 is turned on and the endless belt 5 is heated by infrared radiation. The temperature of the endless belt body 5 is measured by a radiation thermometer 15, and a signal of the measurement result is sent to a control means (not shown) so that the voltage of the halogen heater 12 is feedback-controlled by a power regulator. . By this feedback control, the endless belt body 5 can be heated at a desired temperature increase rate, and can be maintained at a desired temperature for a desired time by a timer programmed in advance in the control means. At that time, the halogen heater 12 is adjusted in advance so as to have an appropriate distance from the endless belt body 5 by using a moving mechanism (14a to 14d) according to the inner diameter of the endless belt body 5.

  Usually, in such a heating apparatus, there is a concern that the temperature drops because both ends in the axial direction (left-right direction in FIG. 1) are more likely to escape heat than the central portion. Therefore, in the present embodiment, both end portions of the halogen heater 12 are adjusted so that the heat generation amount is 10 to 20% larger than the central portion. Therefore, the temperature of the end portion of the endless belt body 5 is not lowered and can be heated uniformly.

  During heating, a gas containing impurities is released from the applied liquid silicone rubber. Therefore, the air inside the closed space surrounded by the heat insulating plate 16 is exhausted from the exhaust port 17, and the outside air is naturally supplied from the gap between the heat insulating plates 16 to replace the gas.

  When the silicone rubber applied to the outer peripheral surface of the endless belt 5 is cured for a predetermined time, the heating is finished (the above is the heating process), the heating of the halogen heater 12 is finished, and the rotation of the motor 11 is stopped. To do. Thereafter, the motor 19 is actuated to open the open / close door composed of the upper heat insulating plate 16a and the upper protective plate 16c, and the holder 1 is lifted together and inclined. In this state, the operator grips the end of the endless belt body 5 using a gripping jig, takes out the endless belt body 5 from the holder, and the heating operation for one cycle using the heating apparatus is completed. .

  Since the peripheral speeds of the outer diameter (≈ circle D) of the endless belt body 5 and the holder 1 are substantially the same during heating, the peripheral lengths of the endless belt body 5 and the circle D are different. It will be different. Therefore, the contact portion between the frame material 8 and the endless belt body 5 is displaced by the difference between the two circumferential lengths every rotation. For this reason, it becomes possible to avoid that the frame | skeleton material 8 contacts the same location in the internal peripheral surface of the endless belt body 5, and it becomes possible to make the frame | skeleton material 8 contact uniformly throughout.

  In general, if the same part is in contact with a jig or the like for a long time during heating, the heat capacity of that part increases and the temperature rise rate due to heating differs from other parts. There is a concern that streaks occur in the appearance of the coating film (silicone rubber layer) after the treatment.

  However, in the heating device of the present embodiment, since the inner peripheral surface of the endless belt body 5 is in uniform contact with the skeleton material 8 as described above, the generation of streaks can be suppressed.

  In addition, when the difference M between the circumferential lengths of the endless belt body 5 and the circle D is an integral multiple of the distance L between the adjacent skeleton members 8, the integral multiple is separated every time the endless belt body 5 makes one rotation. Since the skeletal material 8 comes into contact with the portion where the skeletal material 8 was previously in contact, it is desirable that M does not become an integral multiple of L in order to suppress the generation of streaks.

  However, due to its flexibility, the endless belt body 5 draws a straight line between the adjacent skeleton members 8 at the upper part where it is suspended and in contact with the skeleton member 8 when suspended. Strictly, it does not draw a circle. In addition, the outer shape is strictly larger than the circle D in the upper part where the frame material 8 itself is suspended and in contact with the frame material 8 due to the thickness of the frame material 8 itself. The same applies to the latter when a cylindrical body is used as a heated body instead of the endless belt body 5.

  Therefore, the relationship between M and L may be appropriately adjusted so that the period of the contact portion between the endless belt body 5 and the frame material 8 does not actually overlap in consideration of the two error factors. That is, in the present invention, when the object to be heated is rotated by one rotation following the rotation of the support member, the location of the inner peripheral surface of the object to be heated that has been in contact with the rod-shaped object before the rotation is the rod-shaped object after the rotation. It is desirable to set each condition (peripheral length of the object to be heated, diameter of the circle on which the rod-shaped body is arranged, the number of rod-shaped bodies, the diameter of the rod-shaped body, etc.) so that the cycle does not come into contact.

  By the way, in this invention, even if it is a case where the same location in the inner peripheral surface of the endless belt body 5 comes into contact with the skeleton material 8 due to overlapping cycles, contact and separation are repeated every time rotation is made. Since the state which is carrying out is avoided, compared with the structure like the heating apparatus shown by FIG. 12 which is always contacting with the holder 41 which is a core, the reduction effect of a stripe unevenness can be anticipated.

  In the heating apparatus of the present embodiment, the holder 1 is composed of a skeleton material 8 that is a rod-like body, and only a part thereof is in contact with the endless belt body 5, so that the heat capacity is extremely small and the endless belt body 5. It can suppress that the heat | fever at the time of heating is deprived by the jig | tool (holding tool 1) as a supporting member. Therefore, power consumption during operation can be reduced and energy saving can be achieved. In the present embodiment in which a heat-resistant resin tape is wound around the skeleton material 8, energy saving can be further achieved.

  As described above, the holder 1 of the present heating device is composed of a plurality of skeleton members 8, and when the endless belt member 5 is suspended, the lowermost part of the endless belt member 5 is always separated from the skeleton member 8. Thus, two effects of suppressing the appearance defect such as stripe unevenness and reducing the energy during the heat treatment can be achieved at the same time.

  In the present embodiment, since the heating means is the halogen heater 12 which is an infrared heater arranged at a distance from the outer peripheral surface of the endless belt body 5, it takes time to raise the temperature in the furnace and keeps the furnace at a constant temperature. Compared to a hot air oven or the like that must be heated, the temperature of the heating source itself is increased quickly, and the energy efficiency is much higher, which contributes to energy saving and shortens the processing time.

  In addition, since the reflector 13 for reflecting the infrared rays radiated from the halogen heater 12 to the endless belt body 5 side is disposed at a position opposite to the endless belt body 5 side in the halogen heater 12, the endless belt body is provided. It is possible to irradiate infrared rays uniformly on the irradiation surface of 5, and to prevent defects such as sagging, streaks and pinholes on the appearance of the coating film after heating and curing, and to improve energy efficiency, thus saving energy. Can contribute.

  Further, in the present embodiment, as shown in FIG. 7, the halogen heater 12 as the heating means is the height of the center point of the circle D where the skeleton member 8 is located, that is, the height of the axis 7 (FIG. 7). It is arranged below (in the direction of arrow E) than the middle one-dot chain line). Therefore, the halogen heater 12 can effectively irradiate the region below the endless belt body 5 where the skeleton material 8 is not in contact with infrared rays. Therefore, according to the said structure, since the heat | fever is deprived by the frame | skeleton material 8 and it is suppressed that the nonuniformity | hardening unevenness generate | occur | produces in the coating film of the outer peripheral surface of the endless belt body 5, dripping, a streak, a pin on the external appearance of a coating film Defects such as holes are less likely to occur and energy can be saved.

  Further, in the present embodiment, since the heating means is the halogen heater 12 which is a kind of infrared heater, naturally, heat is generated by application of voltage, and the amount of generated heat increases or decreases according to the magnitude of the applied voltage. And a control means for controlling the temperature of the halogen heater 12 according to the magnitude of the voltage to be applied. For example, by applying a weak voltage to the halogen heater 12, the heating output is reduced. Thus, the temperature can be controlled, and the temperature change of the endless belt body 5 during constant temperature heating is smaller than in the case where the heating source is ON / OFF controlled. For this reason, defects such as sagging, streaks, and pinholes hardly occur in the appearance of the coating film, and energy saving can be achieved.

  As mentioned above, although this invention was demonstrated and mentioned with preferable embodiment, the heating apparatus and heating method of this invention are not limited to the structure of the said embodiment. For example, in the above-described embodiment, the case where the endless belt body is heated is described as an example. However, the present invention can be expected to have the function and effect even when the cylindrical body is heated.

  Moreover, although the holder 1 which consists of 12 frame | skeleton materials (rod-shaped body) 8 is mentioned as an example as a supporting member, there is no restriction | limiting in particular in the number of rod-shaped bodies, and if it is at least 2 or more, to-be-heated material Is suspended and can be rotated, so that the configuration of the present invention is provided. However, in order to smooth the coating film by stable rotation, it is not preferable that the number of rod-shaped bodies is too small, and at least 3 or more, preferably 4 or more, and more than 5 rod-shaped bodies are arranged. It is preferable. The shape of the rod-shaped body is not limited to a cylindrical shape, and an elliptical cylinder (column) shape, a semi-cylindrical (column) shape, and other various shapes can be used as well as a columnar shape. However, the contact surface with the object to be heated is preferably a curved surface.

  Furthermore, in the above-described embodiment, the case where the silicone rubber layer is formed on the fixing belt which is a fixing component of the image forming apparatus has been described as an example. However, in the present invention, not only the fixing roller but also any other cylindrical body or endless belt body. It can use suitably, when forming a coating film in the outer peripheral surface. Among them, the fixing part of the image forming apparatus is required to have high smoothness on the outer peripheral surface, and in particular, the silicone rubber layer is relatively thick and easily causes problems such as uneven stripes and dripping. Is very suitable.

  Furthermore, in the above-described embodiment, an example of a batch method using an infrared heater as a heating unit has been described. However, a conventional hot air heating unit or a continuous heating method including a conveying unit is used. It is also possible. Of course, these are inferior to infrared heaters from the viewpoint of energy efficiency, processing time, and space saving of the apparatus, but a rod-shaped body is used as a support member, heated while being rotated, and hung on the support member. By providing the structure of the present invention in which the lowermost part of the heated object is not in contact with the rod-like body, energy saving can be expected in accordance with it, and appearance defects such as dripping of coating film, pinholes, uneven stripes, etc. can be expected. Suppressing effect can be expected sufficiently.

  In addition, those skilled in the art can appropriately modify the heating apparatus and the heating method of the present invention in accordance with conventionally known knowledge. Of course, such modifications are included in the scope of the present invention as long as the configuration of the heating apparatus or heating method of the present invention is provided.

  Next, the heating device of the present embodiment described above was actually used for heating, and the effect of the present invention was verified. The contents and results of the verification test are shown below.

  An endless belt body 5 made of a polyimide base material (manufactured by Gunze), having an inner diameter of 147 mmφ, a width (length in the axial direction) of 420 mm, and a thickness of 110 μm as an endless belt body 5 used for forming a coating film Two types were prepared, A and an endless belt B having an inner diameter of 80 mmφ, a width (length in the axial direction) of 420 mm, and a thickness of 90 μm. Liquid silicone rubber (LR3390 / 30A, B: Asahi Kasei Wacker) was applied to these substrates so as to have a wet film thickness of 200 μm, followed by heat treatment using the heating apparatus of this embodiment.

  The heating conditions were a set temperature (detection temperature of the coating film surface) of 110 ° C., a heating time of 290 sec, and a rotation gain of the holder 1 of 30 rotations / minute (rpm).

  The distance between the endless belt body 5 and the halogen heater 12 was adjusted to be 50 mm for the endless belt body A and 70 mm for the endless belt body B.

  The temperature rise was varied by the setting of a power regulator that controls the voltage value supplied to the halogen heater 12, and in actuality heating was performed at a setting of 25% output.

  As the halogen heater 12, a coat heater (halogen heater) manufactured by Sakaguchi Heat Transfer Co., Ltd. is used at 1262W (100V, 12.62A), and the light distribution in the portion of 145mm from the end of the total length of 420mm is increased to 135%. used.

  The specification of the holder 1 is that 12 aluminum pipes having an outer diameter of 6 mmφ and an inner diameter of 4 mmφ are arranged as a skeleton material 8 on a 130 mmφ circle (circle D) at equal intervals (angles), and the outer periphery of each skeleton material 8 Was coated with a fluororesin tube having a thickness of 1.0 mm.

  FIG. 9 shows the transition of the temperature change of the surface of the silicone rubber layer formed on the outer peripheral surface of the endless belt body 5 during heating. FIG. 10 shows the result of measuring the temperature of the surface of the silicone rubber layer formed on the outer peripheral surface of the endless belt body 5 when the temperature reaches the set temperature in three directions parallel to the axis 7.

  The position of 0 mm in FIG. 10 indicates the end of the holder 1 on the holding plate size 9a side when the endless belt body 5 is set in the heating device. The reason why the measured value is measured to be low around 100 ° C. while the set temperature is 110 ° C. is that the setting is controlled below the endless belt body 5 on the side irradiated with infrared rays by the halogen heater 12. However, since the surface temperature is measured from the gap between the upper and lower insulating plates 16a and 16c at the upper part, the measurement result is a lower value.

[Comparative Examples 1 and 2]
On the other hand, for comparison, the same heat treatment as in Example 1 was performed using the heating apparatus shown in FIGS. However, as a base material of the objects to be heated 35 and 45, an endless polyimide base material having an inner diameter of 75 mmφ, a width (length in the axial direction) of 390 mm, and a thickness of 90 μm (endless belt body C). Was applied to the liquid silicone rubber in the same manner as in the verification test, followed by heat treatment.

The heating apparatus (Comparative Example 1) shown in FIG. 11 is a batch processing type box-type hot air heating furnace (furnace volume: 0.22 m ² , rated output: 4 kW, maximum temperature: 250 ° C.).

  In the furnace of the said heating apparatus, the to-be-heated material 35 was hold | maintained vertically at the holder 31 as shown in FIG. The temperature in the furnace was set to 120 ° C. and 150 ° C., and the endless belt body 35 held by the holder 31 was put into the place where the temperature of the air in the furnace was at that temperature and heated. The heating time was 290 sec.

  On the other hand, the heating device (Comparative Example 2) shown in FIG. 12 uses a halogen heater 42 and a reflection plate 43 similar to the halogen heater 12 and the reflection plate 13 in this embodiment in a batch processing type box-shaped housing. And it heated, rotating the holder 41 holding the to-be-heated material 45. FIG.

  However, in the comparative example 2, the structure of the holder 41 that holds the object to be heated 45 is different from that of the heating device of Example 1 (the embodiment). Specifically, as the holder 41, the endless belt body C is used. A cylindrical aluminum pipe having an outer diameter slightly smaller than the inner diameter (74 mmφ) is used. As shown in FIG. 12, the endless belt body C is wound around the holder 41 so as to be wound.

  In actual production sites, the inner diameter dimensions of endless belt bodies usually vary within a certain standard, and it is extremely difficult to prepare holders that perfectly match all endless belt bodies. . Therefore, the outer diameter of the holder is adjusted to the minimum value of the standard of the inner diameter dimension of the endless belt body to be held. Therefore, depending on the outer diameter of the endless belt body, there is a gap between the holder and a portion that does not contact and a portion that contacts. In this comparative example 2, this state is reproduced.

  About the above Example 1 and the comparative example 1 and the comparative example 2 for comparing with it, the coating-film external appearance of the formed silicone rubber layer was observed visually and evaluated. The evaluation items were (1) streak irregularity, (2) sagging, and (3) the degree of occurrence of pinholes. The evaluation criteria are as follows.

○: The incidence is less than 1%.
Δ: The incidence is 1% or more and less than 10%.
X: The occurrence rate is 10% or more.

  The “occurrence rate” referred to here is (1) streaks that are visible on the surface of the silicone rubber, (2) sagging that changes in height of 0.2 mm or more occurring in the range of 4 mm at the lower end, (3) The rate of occurrence of pinholes having a size of 0.1 mmφ or more.

  The results are summarized in Table 1 below. In addition, the power consumption of each heating source (per heated object) is also shown.

  As shown in Table 1 above, it is difficult for the heating devices of Comparative Examples 1 and 2 that do not have the configuration of the present invention to satisfy both requirements of the coating film appearance and energy saving, and the configuration of the present invention is implemented. It can be seen from the results of Example 1 that these problems have been solved.

  In the heating method of Comparative Example 1, since the object to be heated is placed vertically and heated, even if the silicone rubber of the coating film does not sag immediately after coating, the silicone rubber is heated in the furnace. The viscosity decreases and the coating film on the upper end of the object to be heated tends to sag. When the coating film at the upper end hangs down, the thickness of the coating film at that location decreases, while the lower end part accumulates dripping silicone rubber, and the region of about 4 mm at the end has a raised shape of about 0.2 to 0.3 mm. It was.

  Therefore, from the heating method of Comparative Example 1, the temperature setting was changed to 180 ° C., the heating time was changed to 290 sec, and the other conditions were the same, and a heating test was further performed. As a result, the time until the silicone rubber layer was cured was shortened, and it was confirmed that the bottom end sagging was alleviated to an area of about 2 mm, but a pinhole-like appearance defect occurred on the coating surface. (Corresponding to “x” in the evaluation criteria in Table 1 above).

  In our experience, when the rate of temperature rise is 2.0 ° C./sec or more, the outermost surface of the silicone rubber is cured before the air entrained in the coating film of the silicone rubber is removed during coating, and then Since air breaks through the cured film and volatilizes, the probability of occurrence of pinhole-like appearance defects on the coating film surface increases. Therefore, in the heating apparatus of Comparative Example 1, it is difficult to suppress both appearance defects such as film thickness disturbance due to sagging and pinholes, no matter how the heating temperature is controlled.

  Further, the heating method using the heating device of Comparative Example 1 has a disadvantage from the viewpoint of energy consumption. Conventionally, when changing a break time or the type of an object to be heated in a production line, there is a time during which heat treatment such as setup is not performed (the furnace is empty). However, like the heating device of Comparative Example 1, a heating furnace using hot air requires time until the inside of the furnace reaches a predetermined temperature (generally, about 30 to 60 minutes). For this reason, the heating device cannot be stopped even when there is empty time in the furnace, and much energy is consumed during that time. Therefore, when converted into the amount of electric power required for heating per object to be heated, the amount of electric power consumption is significantly increased compared to the case where an infrared heater is used as the heating means.

  On the other hand, as described above, in Comparative Example 2, there is a portion that does not come into contact with the endless belt body C and the holder 41, and a portion that does not come into contact therewith. In the part where both are in contact, the heat is taken away by the holder 41 when the infrared rays are irradiated, and the heat applied to the endless belt body C is reduced. On the other hand, the heat is applied to the endless belt body C as it is. As a result, a temperature difference occurs between the two. Therefore, there is a time difference until the silicone rubber layer is cured, the part having the higher temperature is cured first, and the part having the lower temperature that comes into contact with the holder 41 is cured later. Therefore, curing unevenness occurs on the surface of the finally formed silicone rubber layer, and is observed in a streak shape.

  In the heating method using the heating device of Comparative Example 2, since the halogen heater 42 is used as the heating means, the temperature rise after energization is fast, so the halogen heater 42 is stopped during the time when the endless belt body C is not heated. It becomes possible. Therefore, the energy consumption is not as high as in the case of the heating device of Comparative Example 1. However, compared with the case of Example 1 which comprises the structure of this invention, the heat capacity of the holder 41 becomes larger than the holder 1 in this embodiment, and the calorie | heat amount taken away by the said holder increases. For this reason, the energy saving effect is lower than that of the first embodiment.

1: Holder (supporting member)
5: Endless belt body (object to be heated)
5 ': Cylindrical body (object to be heated)
6: Thumb screw 7: Axis 8: Skeletal material (rod-like body)
9a: Large holding plate 9b: Small holding plate 10: Rotating shaft 11, 19: Motor 11a, 11b: Pulley 11c: Timing belt 12: Halogen heater (heating means, infrared heater)
13: Reflector (reflective member)
14a: Guide shaft 14b: Sliding screw 14c: Transmission shaft 14d: Knob 15: Radiation thermometer 15a: Point-view tube 16: Thermal insulation plate 16b, 16c: Protection plate 17: Exhaust port 18: Support shaft 19a: Gear 20: Counterweight 21 : Sensor 22: Start button 23: Work detection sensor 24: Structural material 25: Metal cover 26a, 26b: Maintenance door 30: Housing 31, 41: Holder 35, 45: Heated object 42: Halogen heater 43: Reflector

JP 2000-24586 A JP 2007-245073 A

Claims (8)

In a heating device in which a support member that supports a cylindrical or endless belt-shaped object to be heated from the inside and a heating unit that applies heat to the object to be heated are disposed in the housing.
The support member is composed of a plurality of rod-like bodies that are forested in parallel in a substantially horizontal direction, and the plurality of rod-like bodies are arranged so as to be located on one circumference when viewed from the longitudinal direction,
When the object to be heated is suspended so that all of the plurality of rod-shaped bodies are located inside the object to be heated, the lowermost part of the object to be heated is always separated from the rod-shaped body, and
A heating apparatus, comprising: a rotating means for rotating the support member so that the plurality of rod-shaped bodies move on the circumference.   The heating apparatus according to claim 1, wherein the heating means is disposed below a height of a center point of a circumference where the rod-like body is located.   The heating means is arranged at an interval from the outer peripheral surface of the heated object when the heated object is hung so that all of the plurality of rod-shaped bodies are located inside the heated object. The heating apparatus according to claim 1, wherein the heating apparatus is an infrared heater.   The reflective member which reflects the infrared rays radiated | emitted from the said infrared heater to the said to-be-heated object side is provided in the position on the opposite side to the said to-be-heated object side in this infrared heater. The heating device described. The heating means is a heater that generates heat by applying a voltage, and the amount of generated heat increases or decreases depending on the magnitude of the applied voltage, and
The heating apparatus according to any one of claims 1 to 4, further comprising control means for controlling the temperature of the heater according to the magnitude of the voltage to be applied.   6. The heating apparatus according to claim 1, wherein the object to be heated is a fixing roll or a fixing belt as a fixing part of the image forming apparatus. A heating method for heating an object to be heated in a cylindrical shape or an endless belt using the heating device according to claim 1,
A hanging step of hanging the object to be heated on the support member so that all of the plurality of rod-shaped bodies are located inside the object to be heated;
A heating step of heating the object to be heated by the heating means while rotating the support member by the rotating means;
A heating method characterized by comprising:   The inner periphery-length cylindrical body or endless belt body in which the lowermost portion is always in a state of being separated from the rod-shaped body when suspended on the support member is used as the object to be heated. 8. The heating method according to 7.

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