JP2009288330A - Heat roller, method for manufacturing heat roller, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat roller having improved durability, a method for manufacturing the heat roller, and an image forming apparatus equipped with the heat roller. <P>SOLUTION: The heat roller 52 is used in a fixing device which fixes toner to the surface of a recording medium. That is, the heat roller 52 includes a base body 31 with a cross-section the outline of which is substantially circular, and a film-like heater 33. The film-like heater 33 includes: a first extending portion 333 extending into the base body 31; a body portion 339 continuing from the first extending portion 333 and extending around the outer circumference of the base body 31; and a second extending portion 334 continuing from the body portion 339 and extending into the base body 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention mainly relates to a heat roller used in a fixing device for fixing toner on a recording medium.

  In an image forming apparatus equipped with a heat roller fixing type fixing device, a heat roller and a press roller are pressed against each other to form a nip portion, and the paper passing through the nip portion is heated and pressed to apply toner to the paper. Conventionally, a configuration for fixing to the surface is known.

This type of heat roller has a configuration disclosed in the following patent document, for example. Each of the heat rollers described in these patent documents has an appropriate heater pattern formed on the outer periphery or inner periphery of a cylindrical core material, and heats the surface of the heat roller by energizing the pattern. be able to. In general, the heat roller having this configuration has an advantage that the warm-up time is short and the power consumption is low because the surface of the heat roller can be efficiently heated.
JP-A-8-328414 JP-A-8-110723 JP-A-8-111279 JP-A-8-220916

  The method for manufacturing a heat roller disclosed in Patent Document 1 forms a heater pattern on the surface of a cylindrical core material. On the other hand, in the heat roller manufacturing methods disclosed in Patent Documents 2 to 4, a sheet-like heating element on which a heater pattern is formed in advance is rounded to form a cylindrical body, and the cylindrical core is formed on the outer circumference or inner circumference. Is to be placed. In general, since a process for forming a heater pattern directly on the surface of a cylindrical core material is complicated, from the viewpoint of manufacturing cost and processing accuracy, first, in the form of a sheet, as in Patent Documents 2 to 4 above. A method of forming a cylindrical body by rounding the heating element is excellent.

  By the way, the heat roller having a configuration in which a sheet-like heating element is wound around the outer peripheral surface of the core material has a problem that the heating element is peeled off from the core material after long-term use. Thus, when exfoliation of a heating element arises, the quality of the image formed will fall. Therefore, there is room for improvement in terms of improving the durability of the heat roller and maintaining the quality of the formed image over a long period of time.

  The present invention has been made in view of the above circumstances, and a main object thereof is to provide a heat roller with improved durability.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, there is provided a heat roller used in a fixing device for fixing toner on a recording medium having the following configuration. That is, the heat roller includes a base body having a substantially circular cross-sectional profile and a heater member. The heater member includes a first biting portion that bites into the base body, a main body portion that continues from the first biting portion and makes one round of the outer periphery of the base body, and a second bite that continues to the main body portion and bites into the base body. And a biting portion.

  Thereby, since the biting part of the heater member bites into the base body, the biting part exhibits an anchor effect and can prevent the heater member from peeling off. Therefore, the durability of the heat roller can be improved and the quality of the formed image can be maintained over a long period of time.

  In the heat roller, it is preferable that tips of the first biting portion and the second biting portion are directed in a radial direction of the heat roller.

  Thereby, since the joint of the heater member which made the outer periphery of the base body 1 round can be match | combined without gap, the surface of a heat roller can be heated uniformly by a heater member.

  Further, in the heat roller, the distance between the tip portions of the first biting portion and the second biting portion is such that the first biting portion and the second biting portion are connected to the main body portion. It can also be configured to be larger than the distance.

  Thereby, since the angle which a 1st biting part and a 2nd biting part make with a main-body part becomes an acute angle, a stronger anchor effect can be exhibited and durability of a heat roller can be improved. Moreover, the thickness of the base body of the part which the biting part bites in can be made thin, ensuring the surface area of the biting part and maintaining holding power. Therefore, even a thin cylindrical base body can be used, and material cost reduction and weight reduction can be realized.

  According to a second aspect of the present invention, an image forming apparatus including the heat roller is provided.

  This image forming apparatus can maintain the quality of an image to be formed over a long period of time.

  Moreover, according to the 3rd viewpoint of this invention, the manufacturing method of the heat roller shown below is provided. That is, this heat roller manufacturing method includes a first step, a second step, and a third step. In the first step, at least a part of both end portions of the sheet-like heater member is bent to form a biting portion. In the second step, the cylindrical body is formed by substantially matching both ends of the heater member so that the biting portion is on the inside. In the third step, a base body is disposed inside the cylindrical body so as to bite the biting portion.

  Thereby, since the heat roller which at least one part of the edge part of the heater member digged into the base body can be manufactured, it can prevent that a heater member peels from the said edge part. Therefore, the durability of the heat roller can be improved and the quality of the formed image can be maintained over a long period of time.

  In the method for manufacturing the heat roller, the base body is preferably formed by pouring resin into the inside of the cylindrical body.

  Thereby, the base body which the biting part bite in can be formed easily.

  Next, embodiments of the invention will be described. FIG. 1 is an external perspective view of a copy facsimile multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a front sectional view showing the inside of the main body of the multifunction machine.

  A copy facsimile multifunction machine 75 shown in FIG. 1 includes an image reading unit 76, an operation panel 77, a main body 78, and a paper feed cassette 79.

  The image reading unit 76 is configured to function as a flatbed scanner and an auto document feed scanner. The operation panel 77 is used by the user to instruct the multifunction device 75 such as the number of copies and a facsimile transmission destination.

  The main body 78 incorporates an image forming section for forming an image on a sheet as a recording medium. The main body 78 includes an unillustrated transmission / reception unit for transmitting image data via a communication line. The paper feed cassette 79 is configured so that the paper can be sequentially supplied to the image forming unit.

  The inside of the copy facsimile multifunction machine 75 is shown in FIG. As shown in FIG. 2, a platen glass 82 on which a document to be read is placed is provided on the upper surface of the main body 78. A document table cover 83 is provided above the main body 78, and the document table cover 83 can press and fix the document on the platen glass 82.

  An automatic document feeder (auto document feeder, ADF) 84 is disposed on the document table cover 83. The ADF 84 includes a document tray 85 provided above the document table cover 83, and a discharge tray 86 provided below the document tray.

  As shown in FIG. 2, a curved document transport path 87 that connects the document tray 85 and the discharge tray 86 is formed inside the document table cover 83. A separation roller 88 and a plurality of transport rollers 89 are arranged in the document transport path 87. With this configuration, the documents set on the document tray 85 are separated one by one and conveyed along the curved document conveyance path 87, and after passing through the document reading position, are discharged to the discharge tray 86. The

  As shown in FIG. 2, a scanner unit 90 is provided on the upper portion of the main body 78. The scanner unit 90 includes a light source 91, reflection mirrors 92, 93, 94, a condenser lens 95, and a charge coupled device (CCD) 96.

  The light source 91 irradiates the original reading position of the platen glass 82 or the ADF 84 with light. The reflected light from the original is further reflected by the reflecting mirrors 92, 93, 94, converged by the condenser lens 95, and forms an image on the CCD 96. The CCD 96 converts the convergent light into an electrical signal and outputs it.

  The light source 91, the reflection mirror 92, and the like of the scanner unit 90 are configured to be appropriately movable. Therefore, when the multi-function device 75 is used as a flat bed scanner, the original on the platen glass 82 can be scanned and read by moving the light source 91 and the reflection mirror 92 at a constant speed. When the multi-function device 75 is used as an ADF scanner, the light source 91, the reflection mirror 92, and the like are moved to the original reading position of the ADF 84 and stopped, and the original conveyed on the original conveyance path 87 is scanned and read. be able to.

  As described above, the reflected light from the original is guided to the CCD 96 to form an image, and the CCD 96 outputs an electrical signal corresponding to the original. This signal is sent to an image forming unit 11 (described later) for printing after appropriate conversion processing, or transmitted to another facsimile apparatus via the communication line by the transmission / reception unit.

  As shown in FIG. 2, a paper feed cassette 79 for supplying paper 100 is provided at the lower part of the main body 78. The paper feed cassette 79 is configured to be pulled out to the front side of the apparatus (the front side of the paper in FIG. 2). An image forming unit 11, a fixing device 51, and a paper discharge tray 80 are provided above the paper feed cassette 79.

  Inside the main body 78, a transport path 24 for transporting the paper 100 from the paper feed cassette 79 to the paper discharge tray 80 is formed. The conveyance path 24 extends upward from one end side of the paper feed cassette 79, then curves in the horizontal direction to reach the image forming unit 11, further extends in the horizontal direction, passes through the fixing device 51, and then is discharged. It is configured to reach the paper tray 80.

  A paper feed roller 21 is disposed above the paper feed cassette 79, and is configured such that the paper feed roller 21 contacts the uppermost paper 100 stacked in the paper feed cassette 79. By driving the paper feed roller 21 in this state, the uppermost sheet 100 is separated and picked up and sent out toward the transport path 24.

  Conveying rollers 22 and 23 are arranged immediately downstream of the paper feed roller 21 in the conveying path 24. The transport rollers 22 and 23 are driven while the paper 100 is nipped between the transport rollers 22 and 23 so as to transport the paper 100 to the image forming unit 11 on the downstream side.

  As shown in FIG. 2, the image forming unit 11 is configured by arranging a charger 13, an LED head 14, a developing unit 15, and a transfer roller 16 around the photosensitive drum 12.

  The photosensitive drum 12 is configured such that a photoconductive film made of an organic photoreceptor is formed on the surface and is rotated by an electric motor (not shown). The charger 13 is configured in a brush charging system, and the charger 13 uniformly charges the surface of the photosensitive drum 12, for example, negatively.

  The LED head 14 as an exposure device is disposed downstream of the charger 13 (refers to the downstream side in the rotation direction of the photosensitive drum 12; hereinafter, the same applies to the description of the developing device 15 and the transfer roller 16). In this configuration, a large number of light emitting diodes (LEDs) are arranged in the paper width direction. The LED head 14 selectively emits light corresponding to the image data of the facsimile document received via the telephone line or the image data read by the image reading unit 76. As a result, the surface of the photosensitive drum 12 is selectively exposed, and the electrostatic energy is formed by losing the charge energy of the exposed portion.

  The developing device 15 is disposed on the downstream side of the LED head 14. The developing device 15 includes a toner container 26 that stores nonmagnetic one-component toner, and a stirring blade 27 that is rotationally driven inside the toner container 26 for stirring the toner. Further, the developing device 15 is disposed so as to be in contact with the supply roller 28 disposed in the toner container 26, the development roller 29 disposed in contact with the supply roller 28, and the outer peripheral surface of the development roller 29. And a regulating blade 30 to be operated.

  With this configuration, the supply roller 28 and the developing roller 29 are rotationally driven so as to rub the circumferential surfaces in opposite directions. Further, the tip of the regulating blade 30 rubs against the peripheral surface of the developing roller 29 that is driven to rotate. As a result, the toner in the toner container 26 is frictionally charged and adheres to the surface of the developing roller 29 due to a potential difference. The toner on the surface of the developing roller 29 is adjusted by the regulating blade 30 so that the adhesion thickness is uniform, and is sent to the photosensitive drum 12 side by the rotation of the developing roller 29. Thereafter, in the vicinity of the photosensitive drum 12 and the developing roller 29, the toner on the surface of the developing roller 29 is selectively transferred to the surface of the photosensitive drum 12 only in the portion corresponding to the exposed portion of the photosensitive drum 12 by the LED head 14. Moving. As a result, a toner image is formed on the surface of the photosensitive drum 12.

  The transfer roller 16 is disposed on the downstream side of the developing unit 15 and is disposed on the opposite side of the photosensitive drum 12 with the conveyance path 24 interposed therebetween. A predetermined voltage from a power source is applied to the transfer roller 16. Accordingly, the toner image formed on the surface of the photosensitive drum 12 moves so as to approach the transfer roller 16 side by the rotation of the photosensitive drum 12, and is transferred to the paper 100 by the electric field attraction force. The sheet 100 on which the toner image is transferred is sent to the fixing device 51 on the downstream side of the conveyance path 24 by the rotation of the photosensitive drum 12.

  The fixing device 51 includes a heat roller 52 that is rotationally driven, and a press roller 53 that is disposed to face the heat roller 52. The press roller 53 is pressed against the heat roller 52 by an urging spring. The detailed configuration of the heat roller 52 and the press roller 53 will be described later.

  With this configuration, when the paper 100 passes between the heat roller 52 and the press roller 53, the toner of the toner image is melted and fixed to the paper 100 by the heat of the high-temperature heat roller 52 and the pressure by the press roller 53. To do. The fixing device 51 is provided with a separation claw 54 for preventing the paper 100 from being wrapped around the heat roller 52 while being stuck.

  As shown in FIG. 2, a paper discharge roller 25 is provided on the downstream side of the fixing device 51. With this configuration, the sheet 100 sent from the fixing device 51 is nipped between the sheet discharge roller 25 and a driven roller disposed opposite thereto, and is discharged onto the sheet discharge tray 80.

  Next, a detailed configuration of the fixing device 51 will be described. As shown in FIG. 3, which is an enlarged sectional view, the fixing device 51 includes a housing 55 that houses the heat roller 52 and the press roller 53. A heat roller 52 is rotatably supported on the housing 55 via a bearing 56, and a press roller 53 is rotatably supported via a bearing body 57.

  The bearing body 57 is slidably provided with respect to the housing 55, and an urging spring 58 is interposed between the bearing body 57 and the housing 55. The press roller 53 is pressed against the heat roller 52 by the spring force of the urging spring 58, and both are elastically contacted.

  Next, detailed configurations of the heat roller 52 and the press roller 53 will be described with reference to FIG. 4 is an enlarged cross-sectional view of a region (nip portion) indicated by A in FIG.

  The heat roller 52 includes a base body (heat-resistant carrier) 31, a film heater (heater member) 33, and a release layer 37 as main components. The press roller 53 pressed against the heat roller 52 is arranged on a roller shaft 61 formed of a metal such as stainless steel, a sponge body 62 fixed around the roller shaft 61, and an outer peripheral surface of the sponge body 62. The release layer 63 is provided.

  In the heat roller 52, the base body 31 has a shape (specifically, a cylindrical shape) whose cross-sectional outline is substantially circular, and a film heater 33 configured in a sheet shape outside the base body 31. Is arranged. The heat conductivity of the base body 31 is smaller than the heat conductivity of the film heater 33 (the heat conductivity of the heat transfer layer 36 described later), and the heat capacity of the base body 31 is the heat capacity of the film heater 33 (heat transfer). The heat capacity of the layer 36).

  The film heater 33 disposed outside the base body 31 includes a heating element (heating layer) 35, an adhesive layer 46, and a heat transfer layer (soaking layer) 36.

  The heating element 35 of the film heater 33 can be made of, for example, a nickel alloy such as nickel chrome, nickel, stainless steel, or the like. The heating element 35 has a pattern shape in which a plurality of thin lines are arranged in parallel at equal intervals (heater pattern). The thickness of the heating element 35 is preferably 0.1 μm or more and 100 μm or less, for example, and more preferably about 30 μm. Specifically, sputtering, vapor deposition, metal foil etching, pattern printing, blasting, or the like can be used as a method for creating the heater pattern.

  The adhesive layer 46 is composed of a layer made of a heat-resistant adhesive having electrical insulation (for example, polyimide). The adhesive layer 46 preferably has a composition with high thermal conductivity.

  The heat transfer layer 36 of the film heater 33 is configured to have a thickness of, for example, 1 μm to 50 μm, preferably 10 μm to 30 μm. The heat transfer layer 36 is preferably formed using a layer having a higher thermal conductivity than either of the base body 31 and the heating element 35. Moreover, it is preferable that the heat conductivity of the heat transfer layer 36 is, for example, 10 W / m · K or more. As a material for the heat transfer layer 36, it is conceivable to use a metal such as copper or aluminum. Further, ceramics such as aluminum nitride (AlN) or silicon carbide (SiC) can be used as the heat transfer layer 36.

  A release layer 37 is disposed on the outermost periphery of the heat roller 52. The release layer 37 is made of a material having a high releasability with respect to the toner (a material having a low surface energy and a low intermolecular cohesive force), for example, a fluororesin such as a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer. be able to. As the thickness of the release layer 37, for example, about 30 μm can be considered.

  With the above configuration, the heater pattern of the heating element 35 is energized to cause the heating element 35 to generate heat, and the heat can be uniformly transmitted to the surface of the heat roller 52 by the heat transfer layer 36 having high thermal conductivity. . This heat is transmitted to the release layer 37 disposed on the outermost periphery of the heat roller 52, and finally transmitted to the original document being nipped by the heat roller 52 and the press roller 53. As a result, the surface of the heat roller 52 can be efficiently and uniformly heated, and the toner can be fixed on the surface of the document by the heat.

  Next, the configuration of the heat roller 52 according to the present embodiment will be further described with reference to FIG. FIG. 5 is a schematic cross-sectional view of the heat roller 52.

  As shown in FIG. 5, the film heater 33 constitutes a cylindrical body so that the end portions thereof are abutted, and the main body portion 339 is arranged so as to make one round of the outer periphery of the base body 31. A biting portion (a first biting portion 333 and a second biting portion 334) that bites into the base body 31 is formed at both ends of the main body portion 339. The biting parts 333 and 334 are formed continuously from the main body part 339 via connection parts 331 and 332. With the configuration as described above, the biting portions 333 and 334 exhibit an anchor effect so that the film heater 33 does not peel off from the base body 31.

  Further, the leading ends of the biting portions 333 and 334 face the inside of the heat roller 52 and face the radial direction of the heat roller 52. Thereby, the biting parts 333 and 334 and the connection parts 331 and 332 can be aligned with no gap, and the gap of the joint of the film heater 33 can be minimized.

  In addition, like the heat roller 521 of another embodiment shown in the sectional view of FIG. 6, the interval (distance) between the tips of the biting portions 335 and 336 is larger than the interval (distance) between the connection portions 331 and 332. You may be comprised so that it may become large. In other words, the heat roller 521 is configured such that the connection portions 331 and 332 are substantially aligned with each other, and the leading ends of the biting portions 335 and 336 are separated from each other. If comprised in this way, the anchor effect of the biting parts 335 and 336 will become still stronger, and it can prevent that the biting parts 335 and 336 slip out to the upper side of FIG. The base body 31 is usually configured as a tube having a thickness of about 1 to 2 mm. If the biting portions 335 and 336 are configured as described above, the radial thickness of the portion where the biting portions 335 and 336 are biting can be reduced, so that the thin tube-like base body 31 is also used. Can respond.

  Next, a method for forming the film heater 33 will be described. First, a polyimide adhesive layer having a predetermined thickness is formed on one surface of a copper foil as a substrate. This copper foil corresponds to the heat transfer layer 36 shown in FIG. 5 and the polyimide adhesive layer corresponds to the adhesive layer 46. Then, a stainless steel foil having a thickness of 25 μm is thermocompression bonded to the polyimide adhesive layer.

  Next, the stainless steel foil is processed into a pattern shape having a plurality of lines by a known method such as wet etching. As this heater pattern, for example, a pattern composed of a plurality of parallel lines as shown in FIG. 7 can be considered. As a result of the above processing, a heater pattern-shaped heating element (heating layer) 35 made of stainless steel foil is formed.

  The heating element 35 may be formed by processing the foil-shaped material into a predetermined heater pattern shape by a method such as wet etching, dry etching, or blasting, and then attaching the material to the polyimide adhesive layer 46. Good. Alternatively, a wire-like material previously processed into a heater pattern shape may be attached to the polyimide adhesive layer 46.

  Next, a method for manufacturing the heat roller 52 according to the present embodiment will be described with reference to FIGS. FIG. 8 is a schematic cross-sectional view of a film heater having a biting portion, and FIG. 9 is a schematic view showing a process of forming a base body.

  First, the first step will be described. In this step, the bite portions 333 and 334 are formed by bending one end of the film heater 33 obtained by the above method and the other end on the opposite side. Specifically, a line indicated by a two-dot chain line in FIG. 7 is folded, and both ends of the film heater 33 are bent so as to be raised toward the front side of the paper in FIG. This fold corresponds to the connecting portions 331 and 332. The situation at this time is shown in the sectional view of FIG. As shown in FIG. 8, the adhesive layer 46 is bent together with the heat transfer layer 36 at a substantially right angle with the surface on which the heating element 35 is disposed on the inside, thereby forming the biting portions 333 and 334. In order to manufacture a heat roller as shown in FIG. 6, the end portion may be bent larger than a right angle (so that the main body portion 339 and the biting portions 333 and 334 form an acute angle).

  In the actual manufacturing process, a punching process is performed to form the film-like heater 33 in which the formation of the heater pattern has been completed into a desired shape. At this time, the number of processes can be reduced by performing the bending process. .

  Next, the second step will be described. In this step, the film heater 33 is rounded to form a cylindrical body. Specifically, the cylindrical body is formed by rounding the film heater 33 with the surface on which the heat generating body 35 is disposed inside and the connection portions 331 and 332 being aligned with each other. Thereby, the front-end | tip part of the biting-in part 333,334 is arrange | positioned facing the inner side of a cylindrical body.

  Next, the third step will be described. In this step, the base body is disposed inside the cylindrical body formed by the film heater 33. Hereinafter, this process will be specifically described.

  First, the upper mold | type 101 and the lower mold | type 102 which have a recessed part whose cross-sectional outline is semicircle shape are prepared. The diameters of the semicircular recesses of the upper mold 101 and the lower mold 102 correspond to the outer diameter of the target heat roller. Next, the concave portions of the upper mold 101 and the lower mold 102 are combined to form a cylindrical space. Then, the cylindrical body obtained in the second step is arranged so that the axes coincide with each other in the columnar space. Thereby, since the film-shaped heater 33 is hold | maintained at cylindrical shape, a heat roller can be formed in a desired shape.

  Subsequently, the columnar core 103 is arranged inside the cylindrical body formed by the film heater 33 so that the axes coincide with each other. The outer diameter of the core 103 corresponds to the inner diameter of the cylindrical base body 31. The situation at this time is shown in the schematic diagram of FIG. A molten resin such as polyphenylene sulfide (PPS) is poured into a substantially cylindrical space formed between the film heater 33 and the core 103 arranged as described above (injection). Thereby, the tube-like base body 31 into which the biting portions 333 and 334 bite as shown in FIG. 5 can be obtained by so-called insert molding.

  In the third step, it is preferable that there is no gap at the joint of the film heater 33 (the distance between the connection portions 331 and 332 is zero) from the viewpoint of the image quality of the formed image. However, a slight gap (for example, about 0.1 mm) may be formed at the joint of the film heater 33 based on tolerance or the like. Even in this case, since the resin (molten resin) of the base body 31 enters the gap, the surface of the heat roller 52 can be formed without unevenness. Further, if there is a gap in the film heater 33, the surface temperature of the heat roller 52 is not uniform, but this is not preferable. However, if the gap is about 0.1 mm, for example, the surface temperature of the heat roller 52 will be substantially uniform. There is no problem of image quality degradation.

  After the base body 31 is formed as described above, the mold is opened, and the upper mold 101, the lower mold 102, and the core 103 are removed. Then, a fluororesin layer such as a tetrafluoroethylene / perfluoroalkylvinyl copolymer or the like is formed on the outer peripheral surface of the film heater 33 to form a release layer 37. Through the above steps, the heat roller 52 as shown in FIG. 5 can be manufactured.

  As described above, the heat roller 52 of the present embodiment is used in the fixing device 51 for fixing toner on a recording medium, and is configured as follows. That is, the heat roller 52 includes a base body 31 having a substantially circular cross-sectional profile and a film heater 33. The film heater 33 includes a first biting portion 333 that bites into the base body 31, a main body portion 339 that continues from the first biting portion 333 and makes one round of the outer periphery of the base body 31, and continues to the base body 31 after the main body portion 339. And a second biting portion 334 that bites in.

  Thereby, since the biting parts 333 and 334 of the film-like heater 33 bite into the base body 31, the biting parts 333 and 334 exhibit an anchor effect and prevent the film-like heater 33 from peeling off. it can. Therefore, the durability of the heat roller 52 can be improved and the quality of the formed image can be maintained over a long period of time.

  Moreover, in the heat roller 52 of this embodiment, the front-end | tip of the 1st biting part 333 and the 2nd biting part 334 has faced the radial direction of the heat roller.

  Thereby, since the seam of the film-like heater 33 in which the outer periphery of the base body 31 is made one round can be aligned without a gap, the surface of the heat roller 52 can be uniformly heated by the film-like heater 33.

  In the heat roller 521 according to another embodiment of the present invention, the interval between the tip portions of the first biting portion 335 and the second biting portion 336 is configured to be larger than the interval between the connection portions 331 and 332. Has been.

  Thereby, since the angle which the 1st biting part 335 and the 2nd biting part 336 make with the main-body part 339 becomes an acute angle, a stronger anchor effect can be exhibited and durability of the heat roller 521 can be improved. Moreover, the thickness of the base body 31 in the portion where the biting portions 335 and 336 bite can be reduced while securing the surface area of the biting portions 335 and 336 and maintaining the holding force. Therefore, even a thin cylindrical base body can be used, and material cost reduction and weight reduction can be realized.

  The copy facsimile multifunction machine 75 as the image forming apparatus of the present embodiment includes the heat roller 52 described above.

  Accordingly, the copy facsimile multifunction machine 75 can maintain the quality of the image to be formed over a long period of time.

  Moreover, the manufacturing method of the heat roller 52 of the present embodiment includes a first step, a second step, and a third step. In the first step, both end portions of the film heater 33 are bent to form the biting portions 333 and 334. In the second step, the cylindrical body is formed by substantially matching both ends of the film heater 33 so that the biting portions 333 and 334 are inside. In the third step, the base body 31 is disposed inside the cylindrical body so that the biting portions 333 and 334 are bitten.

  Thereby, since the heat roller 52 in which a part of the end portion of the film-like heater 33 bites into the base body 31 can be manufactured, it is possible to prevent the film-like heater 33 from being peeled off from the end portion. Therefore, the durability of the heat roller 52 can be improved and the quality of the formed image can be maintained over a long period of time.

  Moreover, in the manufacturing method of the heat roller 52 of this embodiment, the base body 31 is formed by pouring resin inside the cylindrical body which the film-like heater 33 comprises.

  Thereby, the base body 31 which the biting part bite in can be formed easily.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be modified as follows, for example.

  In the above configuration, the biting portion is formed over the entire length of the end portion of the film-like heater 33, but instead of this, the biting portion may be formed in a part of the end portion of the film-like heater 33. For example, a bent portion that protrudes in a rectangular shape from the end of the film heater 33 is formed, and the bent portion can be bent to form a biting portion.

  In the above manufacturing method, the biting portion is formed by bending the end portion of the film heater 33. Instead of this configuration, for example, a protruding portion that protrudes in a substantially vertical direction from the surface of the adhesive layer 46 can be changed to a configuration that is integrally formed when the adhesive layer 46 is formed.

  The adhesive layer 46 can be made of, for example, a silicon adhesive instead of the above heat-resistant resin adhesive.

  The shape of the core 103 is not limited to a cylindrical shape, and may be a polygonal column, for example.

  The shape of the base body 31 can be, for example, a columnar shape instead of the cylindrical configuration. In this case, the core 103 can be omitted.

  The material of the base body 31 is not limited to PPS, and other heat resistant resins such as a liquid crystalline polymer can be employed.

  Instead of the method of forming the base body 31 by pouring the resin as described above, for example, the base body 31 is changed to a method of forming the biting portion in advance as a cylindrical body or a cylindrical body in which a groove into which the biting portion can be inserted is formed. Can do. In this case, a heat roller is formed by applying a heat-resistant adhesive to the outer peripheral surface of the base body and disposing a film heater while fitting the biting portion into the groove. According to this method, the base body can be formed of an inorganic material such as alumina, mullite, zirconia, or glass ceramics, or a material that is not suitable for injection molding, such as glass epoxy. However, from the viewpoint of easily forming the base body in which the encroaching portion has eroded, a method of forming the base body by pouring resin is preferable.

  The heater pattern is not limited to the shape described above, and can be formed in an appropriate shape, for example, composed of a plurality of meandering lines.

  The heat roller of the present invention can be applied to various electrophotographic image forming apparatuses such as a copy, a facsimile, a printer, etc., as well as a copy facsimile multifunction peripheral.

1 is an external perspective view of a copy facsimile multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a front cross-sectional view showing the inside of the main body of the multifunction machine. FIG. 3 is an enlarged cross-sectional view showing a state of the fixing device. The cross-sectional enlarged view which shows the part of A of FIG. 3 in detail. The typical sectional view of the heat roller concerning one embodiment of the present invention. The typical sectional view of the heat roller concerning another embodiment of the present invention. The figure which shows the example of a heater pattern shape. The typical sectional view of the film heater which formed the biting part. The schematic diagram which showed the process of forming a base body.

Explanation of symbols

31 Base body 33 Film heater (heater member)
35 Heating element 36 Heat transfer layer (soaking layer)
37 Release layer 46 Adhesive layer 51 Fixing device 52 Heat roller 75 Copy facsimile compound machine (image forming apparatus)
333 First biting portion 334 Second biting portion 339 Main body portion

Claims (6)

A base body having a substantially circular cross-sectional profile;
A first biting portion that bites into the base body, a main body portion that continues from the first biting portion and makes one round of the outer periphery of the base body, and a second biting portion that continues to the main body portion and bites into the base body. A heater member having,
A heat roller for use in a fixing device for fixing toner on a recording medium. The heat roller according to claim 1,
The front end of the first biting part and the second biting part is directed to the radial direction of the heat roller. The heat roller according to claim 1,
The distance between the tip parts of the first biting part and the second biting part is larger than the distance between the parts where the first biting part and the second biting part are connected to the main body part. Heat roller.   An image forming apparatus comprising the heat roller according to any one of claims 1 to 3. A first step of bending the at least part of both end portions of the sheet-like heater member to form a biting portion;
A second step of forming a cylindrical body by substantially matching both ends of the heater member so that the encroaching portion is inside;
A third step of disposing a base body inside the cylindrical body so as to bite the biting portion;
The manufacturing method of the heat roller characterized by including. It is a manufacturing method of the heat roller of Claim 5, Comprising:
The method of manufacturing a heat roller, wherein the base body is formed by pouring resin inside the cylindrical body.

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