JP2007128109A - Fixing roller, fixing device provided with fixing roller, image forming device provided with fixing device and manufacturing method for fixing roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten warming up time for a fixing roller and to improve fixing property for a toner image and transporting property for recording material in a fixing device having recording material carrying the toner image passed between a heated fixing roller and a pressure roller and fixing the toner image on the recording material. <P>SOLUTION: The fixing roller 16 is composed of a base material 23 consisting of a rigid body, a heat insulating layer 25 provided on the surface of the base material, a heat emitting body 31 provided on the surface and a cylindrical member 26 provided on the surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing roller, a fixing device having the fixing roller, an image forming apparatus having the fixing device, and a method for manufacturing the fixing roller.

  In an image forming apparatus configured as a copying machine, a printer, a facsimile machine, or a multifunction machine having at least two of these functions, a toner image is formed on a recording material, and the toner image is fixed by a fixing device. Yes. Conventionally known fixing devices include a heat fixing method, a pressure fixing method, and a solvent fixing method. Among them, the heat fixing type fixing device applies heat and pressure to the toner on the recording material to fix the toner image on the recording material, and is a fixing method widely used conventionally. The most common fixing device of such a heat fixing system has a fixing roller and a pressure member pressed against the fixing roller, and the toner image is formed between the fixing roller and the pressure member by heating the fixing roller. Is a fixing device that fixes the toner image on the recording material by passing the recording material carrying the toner. Further, an endless fixing belt is wound around the fixing roller and other rollers, and a pressure member is pressed through the fixing belt, the fixing belt is heated, and the recording material is interposed between the fixing roller and the pressure member. Conventionally, a fixing device of a heat fixing type that fixes the toner image on the recording material by passing the toner is also well known.

  In the above-described heat fixing type fixing device, the fixing roller or the fixing belt needs to have a fixing temperature suitable for fixing the toner image during the fixing operation of the toner image. For this reason, when the power of the image forming apparatus is turned on, the fixing operation must be started after the fixing roller or the fixing belt reaches the fixing temperature. The time required for the fixing roller or the fixing belt to reach such a fixing temperature is generally referred to as a warm-up time. However, in the conventional fixing device, this warm-up time becomes long, which causes great inconvenience to the user. There was a fear.

  In view of this, it is conceivable to reduce the thickness of the fixing roller to reduce its heat capacity so that the fixing roller or the fixing belt can be heated to the fixing temperature in a short time. The thinner the fixing roller, the shorter the warm-up time and the shorter the waiting time for the user.

  However, when the thickness of the fixing roller is reduced, the rigidity of the fixing roller decreases, and the center in the longitudinal direction of the fixing roller pressed against the pressure member directly or via the fixing belt is bent or elastically crushed and deformed. The recording material transported between the roller and the pressure member is wrinkled, and the transportability of the recording material is reduced, and the toner image cannot be given a predetermined uniform pressure and heat necessary for fixing. There is a risk that the image cannot be fixed reliably. As described above, in a fixing device using a fixing roller, it is necessary to simultaneously satisfy the two requirements of shortening the warm-up time and preventing the rigidity of the fixing roller from being lowered. It was difficult to satisfy the requirements at the same time.

  A first object of the present invention is to provide a fixing roller capable of shortening the warm-up time as compared with the prior art and suppressing the decrease in rigidity.

  A second object of the present invention is to provide a fixing device having the fixing roller.

  A third object of the present invention is to provide an image forming apparatus having the fixing device.

  A fourth object of the present invention is to provide a method for manufacturing the fixing roller.

  In order to achieve the first object, the present invention provides a cylindrical base material made of a rigid body, a heat insulating layer disposed outside the base material, and a cylindrical member provided outside the heat insulating layer. A fixing roller is proposed (claim 1).

  In that case, it is advantageous to have a heating element disposed between the heat insulating layer and the cylindrical member (claim 2).

  The fixing roller according to claim 1, wherein the base material includes a transparent glass tube in which a radiant heater is disposed, and the heat insulating layer is sparsely disposed on an outer peripheral surface of the transparent glass tube. (Claim 3).

  Furthermore, in the fixing roller according to any one of the first to third aspects, it is advantageous that the heat insulating layer is made of a heat-resistant resin film stacked in multiple layers (claim 4).

  In the fixing roller according to any one of claims 1 to 3, it is advantageous that the heat insulating layer is formed of a heat-resistant resin film having holes stacked in multiple layers (claim 5).

  Further, in the fixing roller according to any one of claims 1 to 3, it is advantageous that the heat insulating layer is made of a porous heat resistant resin (claim 6).

  In the fixing roller according to any one of claims 1 to 6, it is advantageous that the cylindrical member is made of a metal having a thickness of 0.3 mm or less.

  Furthermore, in order to achieve the second object, the present invention proposes a fixing device comprising the fixing roller according to any one of claims 1 to 7 and a pressure member that presses the fixing roller ( Claim 8).

  The fixing device according to claim 8, further comprising an endless fixing belt wound around a fixing roller not having the cylindrical member and another roller, instead of the cylindrical member. A fixing roller not having a cylindrical member and the pressure member may be in pressure contact with each other via the fixing belt.

  In order to achieve the third object, the present invention further comprises a fixing device according to claim 8 or 9, and an image forming means for forming a toner image fixed by the fixing device on a recording material. An image forming apparatus is proposed (claim 10).

  Further, in order to achieve the fourth object, the present invention constitutes a roller body in which a fixing roller member other than the cylindrical member is integrated, and after thermally expanding the cylindrical member, 8. The method of manufacturing a fixing roller according to claim 1, wherein the roller body is inserted, the cylindrical member is then cooled, and the cylindrical member and the roller body are integrated. (Claim 11).

  According to the first and second aspects of the invention, since the heat insulating layer is provided between the base member of the fixing roller and the cylindrical member, the warm-up time of the cylindrical member can be shortened, and the cylindrical base member Thus, the rigidity of the fixing roller can be increased, and the fixing property of the toner image and the conveyance property of the recording material can be improved.

  According to the invention of claim 3, since the heat insulating layer is provided between the base member of the fixing roller and the cylindrical member, the warm-up time of the cylindrical member can be shortened, and the fixing is performed by the cylindrical base member. The rigidity of the roller can be increased, and the fixing property of the toner image and the conveyance property of the recording material can be improved. Furthermore, since the base material is made of a transparent glass tube and the heat insulating layer is sparsely arranged, the radiant heat from the radiant heater in the base material can be efficiently transmitted to the cylindrical member.

  According to the invention which concerns on Claim 4, since an air layer is made between heat resistant resin films, the heat insulation effect of a heat insulation layer can be improved.

  According to the invention which concerns on Claim 5, since the heat insulation layer which piled up the heat-resistant resin film with a hole in multiple numbers was used, there exists a lot of air in the heat insulation layer heat, and this raises the heat insulation of a heat insulation layer more be able to.

  According to the invention which concerns on Claim 6, since a heat insulation layer is porous, a large amount of air exists in a heat insulation layer, and this can improve the heat insulation of a heat insulation layer more.

  According to the invention which concerns on Claim 7, since the heat capacity of a cylindrical member can be made very small, warm-up time can be shortened more reliably.

  According to the eighth and ninth aspects of the present invention, it is possible to provide a fixing device in which the warm-up time is shortened and the recording material conveyance property and toner fixing property are enhanced.

  According to the tenth aspect of the present invention, it is possible to provide an image forming apparatus provided with a fixing device that shortens the warm-up time and improves the transportability of the recording material and the fixing property of the toner.

  According to the invention which concerns on Claim 11, a fixing roller can be manufactured easily.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a vertical sectional view of a laser printer as an example of an image forming apparatus. The image forming apparatus shown here includes an image forming means 30 for forming a toner image on a recording material, and a toner image on the recording material. And a recording material feeding device 7 for feeding a recording material to the image forming means 30. First, the configuration and operation of the image forming means 30 will be clarified.

  The image forming unit 30 illustrated in FIG. 1 includes a drum-shaped photoconductor 2 that is an example of an image carrier disposed inside the image forming apparatus main body 1. When the printing operation is performed, the photoconductor 2 is It is rotationally driven counterclockwise in FIG. At this time, the charging device 3 uniformly charges the surface of the photosensitive member to a predetermined polarity, and the charged surface is irradiated with light-modulated laser light L emitted from a laser writing unit 4 which is an example of an exposure device. As a result, an electrostatic latent image is formed on the photoreceptor.

  The electrostatic latent image is visualized as a toner image by the developing device 5. The developing device 5 shown here has a developing case 18 containing a powdery developer D and a developing roller 6 that carries and conveys the developer, and the toner of the carried developer is photosensitive. The electrostatic latent image is electrostatically transferred to the body surface and the electrostatic latent image is visualized as a toner image.

  Further, the image forming means 30 of the present example includes a transfer roller 11 which is an example of a transfer device that transfers a toner image formed on the photoreceptor 2 onto a recording material as will be described later, and a surface of the photoreceptor after transfer. A cleaning device 12 for removing the transfer residual toner adhering thereto and a separation claw 15 for separating the recording material from the photosensitive member are provided.

  Next, the configuration and operation of the recording material feeding device 7 will be described.

  The recording material feeding device 7 includes a cassette 8 disposed at a lower portion of the image forming apparatus main body 1, a feeding roller 9, and a pair of registration rollers 10, and the recording material P accommodated in the cassette 8 is fed. The sheets are fed one by one by the rotation of the feeding roller 9. The recording material P that has been sent out stops once with its leading end abutting against the pair of registration rollers 10. Next, the registration roller 10 starts to rotate at a predetermined timing, whereby the recording material is positioned between the transfer roller 11 and the photosensitive member 2 at a timing that matches the toner image formed on the photosensitive member 2. To the transfer portion (in the direction of arrow A). When the recording material passes through the transfer portion, the toner image on the surface of the photoreceptor is transferred to the surface of the recording material. As the recording material P, paper, a resin sheet, a resin film, or the like is used.

  The transfer residual toner that is not transferred to the recording material P and adheres to the surface of the photoconductor is removed from the surface of the photoconductor by the cleaning member 13 of the cleaning device 12, and the surface is cleaned. The recording material P is separated from the photosensitive member 2 by the action of a separating device including the static elimination needle 15.

  Next, the outline of the fixing device 14 will be described.

  The fixing device 14 shown in FIG. 1 has a fixing roller 16 and a pressure roller 17 as an example of a pressure member, and these rollers 16 and 17 are in pressure contact with each other in the direction indicated by the arrow in FIG. Each rotates. The recording material separated from the photoreceptor 2 by the charge eliminating needle 15 passes between the fixing roller 16 and the pressure roller 17, and at this time, the toner on the recording material is melted by the action of heat received from the fixing roller 16, In addition, pressure is received from the fixing roller 16 and the pressure roller 17. In this way, the toner image on the recording material is fixed on the recording material. The recording material that has passed through the fixing device 14 is discharged onto a paper discharge tray 20 constituted by an exterior cover of the image forming apparatus main body 1 by a paper discharge roller pair 19.

  Further, the fixing device 14 of this example has a thermistor 24 which is an example of a temperature detecting means for detecting the surface temperature of the fixing roller 16, and the thermistor 24 is in contact with the surface of the fixing roller 16. The fixing roller 16 is heated to a fixing temperature suitable for fixing the toner image based on the temperature detection result of the thermistor 24.

  The pressure roller 17 is positioned parallel to the fixing roller 16 and includes a metal core 21 made of a metal rigid body and an elastic body layer 22 made of, for example, silicone rubber and fixed to the outer peripheral surface thereof. The body layer 22 is elastically deformed into a compressed state at the pressure contact portion with the fixing roller 16, thereby forming a nip N having a predetermined width in the recording material conveyance direction.

  The basic configuration and operation of the image forming apparatus shown in FIG. 1 have been described above. The fixing device 14 of this image forming apparatus, particularly the fixing roller 16 thereof, is configured in various modes as will be described below.

  FIG. 2 is an enlarged sectional view showing the fixing roller 16 of the first example. The fixing roller 16 illustrated here includes a cylindrical base 23 made of a rigid body, a heat insulating layer 25 disposed on the outer side in the radial direction of the base 23, and a cylinder provided on the outer side in the radial direction of the heat insulating layer 25. 2, in the example shown in FIG. 2, the heat insulating layer 25 is fixed directly to the outer peripheral surface of the base material 23, and the cylindrical member 26 is fixed directly to the outer peripheral surface of the heat insulating layer 25. These elements 23, 25 and 26 are arranged concentrically.

  The base material 23 is made of, for example, hard resin, metal, glass, or a composite material thereof, and the thickness is preferably 2 mm or more.

  Moreover, the heat insulation layer 25 is comprised by resin excellent in heat resistance, for example. Specifically, although the heat insulating layer 25 made of polyimide is particularly excellent, other organic and inorganic materials such as polyimide amide, aramid, polybenzobisoxazole, polybenzimidazole, liquid crystal polyester, polyphenylene sulfide, silicone, alumina, Alternatively, the heat insulating layer 25 can be made of a composite material of these materials and a material including polyimide.

  The cylindrical member 26 is made of a thin resin or metal, and in particular, it is advantageous to use the cylindrical member 26 having a particularly small heat capacity made of a metal having a thickness of 0.3 mm or less, preferably 0.2 mm or less. It is. A release layer 29 made of, for example, a fluorine-based resin is formed on the outer peripheral surface of the cylindrical member 26 so that the toner on the recording material P does not easily move. However, the release layer 29 is omitted. You can also.

  The above-described fixing roller 16 is heated by an appropriate heating means. For example, as shown in FIG. 2, a heating roller 28 provided with a heater 27 is brought into contact with the outer peripheral surface of the fixing roller 16 to rotate the fixing roller 16. Along with this, the heating roller 28 heated by the heater 27 is rotated in the direction indicated by the arrow in FIG. 2, whereby the surface of the fixing roller 16 can be heated to a temperature suitable for fixing the toner image. The fixing roller 16 can also be heated by radiation, convection, or induction heating means from the outside of the fixing roller 16.

  According to the fixing roller 16 described above, the fixing roller 16 and the heating roller 28 start rotating when the power of the image forming apparatus is turned on. When the heater 27 is energized, the heat is applied to the fixing roller 16 via the heating roller 28. The cylindrical member 26 is transmitted to the cylindrical member 26 and heated, but the cylindrical member 26 has a small heat capacity, and the heat insulating layer 25 exists inside thereof, so that the heat of the cylindrical member 26 is not easily transmitted to the base material 23. . Therefore, the cylindrical member 26 can be heated to a temperature suitable for fixing the toner image in a very short time, and the warm-up time can be shortened reliably.

  In addition, when the fixing roller 16 and the pressure roller 17 are rotated in the direction indicated by the arrows in FIG. 1 and the recording material is passed between the rollers 16 and 17, the fixing operation of the toner image is performed. 16 has a base material 23 made of a rigid body and a heat insulating layer 25 on the center side thereof, so that the fixing roller 16 exhibits high rigidity. In particular, since the base material 23 is formed in a hollow cylindrical shape, its rigidity is remarkably increased compared to the case where a base material made of a solid shaft manufactured using the same amount of material is employed. Can do.

  Since the rigidity of the fixing roller 16 can be increased as described above, the central portion in the longitudinal direction of the fixing roller 16 pressed by the pressure roller 17 is not greatly elastically bent or greatly crushed and deformed. The nip N (FIG. 1) necessary for fixing the toner image can be secured, and the uniform pressure and heat amount required for fixing can be applied to the toner on the recording material. As a result, the toner image can be reliably fixed on the recording material (improvement of fixability), and the problem of wrinkles occurring on the recording material conveyed while being sandwiched between the fixing roller 16 and the pressure roller 17 can be prevented (recording material). Improved transportability).

  The fixing roller 16 of the second example shown in FIG. 3 has a heating element 31 disposed between the heat insulating layer 25 and the cylindrical member 26, and the heating element 31 has a surface on the cylindrical member 26 side. Is laminated with an electrically insulating layer 33 such as a polyimide film. Other configurations are the same as those of the fixing roller shown in FIG. The heating element 31 is constituted by a resistor made of, for example, a metal sheet or film, and heats the heating element 31 by energizing the heating element 31, thereby heating the cylindrical member 26 of the fixing roller 16. Even with this configuration, the heat capacity of the cylindrical member 26 on the outside is small, and the heat of the cylindrical member 26 is not easily transmitted to the side of the base material 23 by the heat insulating layer 25, and is further fixed by the base material 23 and the heat insulating layer 25. Since the roller 16 has a large rigidity, the warm-up time can be shortened in the same way as the fixing roller shown in FIG. The generation of wrinkles can be prevented.

  In the fixing roller 16 of the third example schematically shown in FIG. 4, the base material 23 is made of a transparent glass tube, and a radiant heater 32 made of, for example, a halogen heater is disposed therein. Around the base material 23 made of a transparent glass tube, a heat insulating layer 25 made of the material exemplified above is provided. The heat insulating layer 25 in this example is formed on the outer peripheral surface of the base material 23 made of a transparent glass tube. Sparsely arranged.

  FIG. 5 is a side view of the fixing roller when the cylindrical member 26 shown in FIG. 4 is removed to expose the heat insulating layer 25. In the example shown here, the heat insulating layer 25 is formed in a tape shape. Then, such a tape-like heat insulating layer 25 is spirally wound around the surface of the cylindrical base material 23 made of a transparent glass tube with a gap G therebetween. The heat insulation layer 25 is sparsely arranged with a gap G on the outer peripheral surface of the transparent glass tube. Around the heat insulating layer 25, a cylindrical member 26 configured in the same manner as in the previous example is fixed. The other configuration of the fixing roller 16 shown in FIG. 4 is the same as that of the fixing roller shown in FIG. 1, and is not different from the fixing roller shown in FIG. 1 in that a heating element is not provided.

  In the above-described third fixing roller 16, the radiant heat generated in the heater 32 by energizing the radiant heater 32 passes through the base material 23 made of a transparent glass tube, and the gap between the tape-like heat insulating layers 25. It passes through G to reach the cylindrical member 26 where it is absorbed, thereby heating the cylindrical member 26. Also with this configuration, the cylindrical member 26 having a small heat capacity is heated by energizing the radiation heater 32 when the image forming apparatus is turned on, and the heat of the cylindrical member 26 is heated by the action of the heat insulating layer 25. Therefore, it is possible to reduce the warm-up time by raising the temperature of the cylindrical member 26 to the fixing temperature at an early stage. Since the heat insulation layer 25 is located sparsely with a gap G on the base material 23, the heat from the radiant heater 32 is hardly absorbed by the heat insulation layer 25, and the cylindrical member 26 is efficiently passed through the gap G. In addition, the heat of the cylindrical member 26 can be made difficult to be transmitted to the base material 23 side by the heat insulating layer 25. In addition, the rigidity of the fixing roller 16 can be increased by the cylindrical base material 23 made of a transparent glass tube and the heat insulating layer 25, so that the toner image can be fixed as in the case of the example described above. In addition, the recording material can be conveyed without causing wrinkles in the recording material, and the conveyance property of the recording material can be improved.

  As the radiant heater 32, a heater that generates light having a short wavelength emission distribution with excellent transparency in glass is used, and the color temperature is preferably 2700 K or more.

  In the case of the fixing roller 16 of the second and third examples shown in FIGS. 3 to 5, during the warm-up (rise) of raising the temperature of the cylindrical member 26 of the fixing roller 16 to the fixing temperature, The fixing roller 16 may be kept stopped or may be rotated.

  As the heat insulating layer 25 of the fixing roller 16 in each of the above examples, a single layer film or sheet made of the material exemplified above may be used. However, as shown schematically in FIG. It is advantageous to use a multi-layered heat-resistant film 34 having a thickness t of about 50 μm, for example. As the film 34, for example, a film made of the resin exemplified above can be used. Thus, when the heat insulation layer 25 is composed of the heat-resistant resin films 34 stacked in multiple layers, a minute air layer AG is formed between the films, and thereby the elasticity can be remarkably improved.

  In addition, as schematically shown in FIG. 7, for example, the heat-insulating layer 25 in which the heat-resistant films 36 made of the resin exemplified above are stacked in multiple layers and the holes 35 are formed in each film 36 can be used. . As described above, when the heat insulating layer 25 made of the heat resistant resin film 36 with the holes 35 stacked in multiple layers is used, the contact area of each film 36 is reduced, and more air exists in the heat insulating layer 25. Therefore, it is possible to further improve the heat insulation and further reduce the form-up time of the fixing roller 16.

  Furthermore, as schematically shown in FIG. 8, for example, a sheet-like heat insulating layer 25 in which a large number of voids are formed by sintering polyimide powder can be used. As described above, when the heat insulating layer 25 made of a porous heat resistant resin is used, more air can be present in the inside thereof, and the heat insulating property can be more reliably improved.

  The fixing device 14 shown in FIG. 1 includes the fixing roller 16 in the above-described example and a pressure roller 17 that is an example of a pressure member that is in pressure contact with the fixing roller 16. Instead, for example, a pressure member composed of a pressure belt that is wound around and driven by a plurality of rollers is used, and the pressure belt is brought into pressure contact with the fixing roller 16, and between the fixing roller 16 and the pressure belt. It is also possible to pass the recording material and fix the toner image on the recording material by the action of heat and pressure.

  It is also possible to configure the fixing device by omitting the cylindrical member 26 from the fixing roller 16 having each configuration described above and winding a fixing belt around the fixing roller not having the cylindrical member and another roller.

  9 shows an example in which the fixing roller 16 formed by removing the cylindrical member 26 from the fixing roller 16 shown in FIG. 2 and another roller 37 have a thickness of 0.2 mm or less, preferably 0.1 mm or less. An example of the fixing device 14 is shown in which an endless metal fixing belt 38 is wound and a pressure roller 17, which is an example of a pressure member, is pressed against the fixing roller 16 via the fixing belt 38. . A heater 41 made of, for example, a halogen heater is disposed in the space in the fixing belt between the fixing roller 16 and the roller 37, and the fixing roller 16 and the fixing belt 38 are heated by energizing the heater 41. It is preferable that a release layer 39 made of, for example, a fluorine resin is formed on the surface of the fixing belt 38 so as to prevent the toner from adhering to the surface of the fixing belt 38. Thus, instead of the cylindrical member, an endless fixing belt 38 wound around the fixing roller 16 and the other roller 37 that does not have the cylindrical member is provided, and the fixing belt 38 is interposed through the fixing belt 38. The fixing device 14 is configured so that the fixing roller 16 that does not have a cylindrical member is in pressure contact with the pressure member. The fixing device 14 also heats the fixing roller 16 and the fixing belt 38 by energizing the heater 41 while rotating the fixing roller 16, the roller 37, the fixing belt 38, and the pressure roller 17 during the warm-up. When this is done, the temperature can be raised to the fixing temperature at an early stage to shorten the warm-up time. In addition, the overall rigidity of the fixing roller 16 can be increased by the base material 23 having a high rigidity, and the fixability of the toner image and the transportability of the recording material during the fixing operation can be improved.

  Further, if the roller 37 also has a cylindrical base material 23A having high rigidity and a heat insulating layer 25A fixed to the outer peripheral surface thereof, the heat of the fixing belt 38 is difficult to transfer to the roller 37, and the fixing is performed. The warm-up time of the belt 38 can be further shortened.

  A fixing device similar to the fixing device 14 shown in FIG. 9 may be configured by winding a fixing belt around the fixing roller formed by removing the cylindrical member 26 from the fixing roller 16 shown in FIGS. This fixing device can also provide the above-described effects. In this case, the heater 41 shown in FIG. 9 can be omitted.

  The image forming apparatus shown in FIG. 1 forms each of the fixing rollers 16 described above or the fixing device 14 having the fixing roller 16 and a toner image fixed by the fixing device 14 on the recording material P. Although an example of an image forming apparatus including the means 30 is shown, various types of image forming means other than those shown in FIG. 1 can be adopted as the image forming means.

  The above-described fixing roller 16 having the cylindrical member 26 can be manufactured by an appropriate method, but the fixing roller 16 can also be easily manufactured as follows.

  As shown in FIG. 10 (a), a cylindrical member 26 is prepared, and this cylindrical member 26 is heated and expanded as shown in FIG. 10 (b) (the expansion direction is indicated by an arrow). Increase the diameter. On the other hand, the members of the fixing roller other than the cylindrical member 26 are integrated to form the roller body 40. As shown in FIG. 10C, the roller body 40 is inserted into the expanded cylindrical member 26, Next, as shown in FIG. 10D, the cylindrical member 26 is cooled to reduce its diameter (the shrinking direction is indicated by an arrow), and the cylindrical member 26 and the roller body 40 are integrated. You may fix each member which comprises the fixing roller 16 with an adhesive agent. Moreover, the release layer 29 on the surface of the cylindrical member 26 may be formed before the cylindrical member 26 is integrated with the roller body 40 or may be formed after the integration.

  The means for heating the fixing roller 16 and the fixing belt 38 in each example described above is not limited to the example shown in the figure, and may include heat conduction from outside, radiation, convection, induction heating means from at least one of the outside and inside, as appropriate. Can be adopted.

  Next, more specific examples and comparative examples of the fixing device will be described.

  The cylindrical member 26 of the fixing roller 16 used in each example and comparative example has an outer diameter of 50 mm and a length of 365 mm, and a release layer 29 made of PFA resin is laminated on the surface thereof. The cylindrical member 26 is all made of aluminum, and its thickness is as described later. The pressure roller 17 in pressure contact with the fixing roller 16 is provided with an elastic body layer 22 made of silicone rubber on a core metal 21, and pressurizes each end in the longitudinal direction with a force of 120N. The roller 17 was brought into pressure contact with the fixing roller 16, and the width of the contact portion of both the rollers 16 and 17, that is, the nip N was about 9 mm. The target temperature of the fixing roller 16 is set to 160 ° C., the fixing roller is warmed up so that the surface temperature becomes 160 ° C., and the surface temperature of the fixing roller 16 is set to 160 ° C. during the fixing operation. The temperature was controlled, and the recording material made of paper was passed between the fixing roller 16 and the pressure roller 17 rotating at a speed of 330 mm / second, and the toner image on the recording material was fixed. Table 1 shows the results of the evaluation of the warm-up time when the 1200 W was loaded, the recording material transportability, and the toner image fixing property.

More specific configurations and heating methods of the fixing roller 16 in each of the examples and comparative examples in Table 1 are as follows.
(1) Example 1-1 (see FIG. 3)
Cylindrical member 26: made of aluminum having a thickness of 0.2 mm.
Heating method: An insulating layer 33 made of a polyimide film having a thickness of 25 μm is disposed on the inner peripheral surface of the cylindrical member 26, and a heating element 31 made of stainless steel is disposed on the inner side thereof. The heating element 31 was heated. A tape-shaped heating element 31 was attached to the outer peripheral surface of the heat insulating layer 25 by being spirally wound at intervals in the axial direction of the fixing roller 16.
Thermal insulation layer 25: a polyimide molded product having a thickness of 0.2 mm.
Base material 23: made of aluminum having a thickness of 2 mm.
(2) Example 1-2 (see FIG. 3)
Cylindrical member 26: Same as Example 1-1.
Heating method: the same as Example 1-1.
Insulating layer 25: a polyimide film having a thickness of 50 μm superimposed on four layers (see FIG. 6).
Substrate 23: Same as Example 1-1.
(3) Example 1-3 (see FIG. 3)
Cylindrical member 26: Same as Example 1-1.
Heating method: the same as Example 1-1.
Heat insulation layer 25: A hole having a 50% area ratio was made in a polyimide film having a thickness of 50 μm, and the film was superimposed on four layers (see FIG. 7).
Substrate 23: Same as Example 1-1.
(4) Example 1-4 (see FIG. 3)
Cylindrical member 26: Same as Example 1-1.
Heating method: the same as Example 1-1.
Thermal insulation layer 25: A polyimide powder sintered to a porosity of 60% and a thickness of 0.2 mm (see FIG. 8).
Substrate 23: Same as Example 1-1.
(5) Comparative Example 1-1
Cylindrical member 26: Same as Example 1-1.
Heating method: the same as Example 1-1.
Thermal insulation layer: None Base material: None (6) Comparative Example 1-2
Cylindrical member 26: made of aluminum having a thickness of 2 mm.
Heating method: the same as Example 1-1.
Thermal insulation layer: None Base material: None (7) Comparative Example 1-3
Cylindrical member 26: made of aluminum having a thickness of 1.5 mm.
Heating method: the same as Example 1-1.
Thermal insulation layer: None Base material: None (8) Example 2 (see FIGS. 4 and 5)
Cylindrical member 26: made of aluminum having a thickness of 0.2 mm.
Heating method: energizing the halogen heater 32 disposed in the center of the substrate 23.
Insulating layer 25: Four layers of polyimide films having a width of 5 mm and a thickness of 50 μm were spirally wound around the outer peripheral surface of the substrate 23 with a gap G of 15 mm.
Base material 23: Transparent glass tube with a wall thickness of 2 mm.
(9) Comparative Example 2-1
Cylindrical member 26: the same as in Example 2.
Heating method: the same as in Example 2.
Thermal insulation layer: None Base material: None (10) Comparative Example 2-2
Cylindrical member 26: made of aluminum having a thickness of 2 mm.
Heating method: the same as in Example 2.
Thermal insulation layer: None Base material: None (11) Comparative Example 2-3
Cylindrical member 26: made of aluminum having a thickness of 1.5 mm.
Heating method: the same as in Example 2.
Thermal insulation layer: None Base material: None (12) Example 3 (see FIG. 9)
Fixing belt: Made of stainless steel with a thickness of 0.1 mm.
Heating method: energizing the halogen heater 41 disposed inside the fixing belt 38.
Thermal insulation layer 25: a polyimide powder sintered to a porosity of 60% and a thickness of 0.2 mm (see FIG. 8).
Base material 23: made of aluminum having a thickness of 2 mm.

  In Example 3, both the fixing roller 16 and the fixing belt 38 are rotated when the fixing roller 16 and the fixing belt 38 are warmed up. In other cases, the fixing roller 16 is stopped during the warming up. “◯” in Table 1 indicates that no wrinkles were generated on the recording material, the recording material was well conveyed, and the toner image was well fixed, and “x” was not. It shows that.

  As can be seen from Table 1, in the case of the comparative example without the base material 23, when the thickness of the cylindrical member 26 is smaller than 2 mm, the conveyance of the recording material cannot be satisfied. This is because the central portion of the fixing roller 16 in the longitudinal direction is bent or crushed due to insufficient rigidity of the fixing roller 16, and the transportability of the recording material is deteriorated. In particular, in Comparative Examples 1-1 and 2-1, because the thickness of the cylindrical member 26 was as extremely thin as 0.2 mm, the fixing roller 16 was completely deformed and wrinkles were generated in all the recording materials. Moreover, the toner image cannot be satisfactorily fixed. This is because the nip N (FIG. 1) necessary for fixing the toner image cannot be obtained due to the deformation of the fixing roller 16.

  On the other hand, in Comparative Examples 1-2 and 2-2, since the thickness of the cylindrical member 26 is as thick as 2 mm, the conveyance of the recording material and the fixing property of the toner image are satisfied, but are significantly longer than the examples. Warm-up time is required. When such a fixing roller 16 is used, the power is on, but it is necessary to preheat the fixing roller 16 to a standby temperature lower than the fixing temperature when the printer is in a standby state. However, if such preheating is performed, a problem of consuming a large amount of energy even when the fixing device is not used is inevitable.

  In Examples 1-1, 1-2, and 1-3, the cylindrical member 26 is heated by heat transmission from the heating element 31, and the heat of the cylindrical member 26 is transmitted to the base material 23 by the heat insulating layer 25. Can prevent warm-up time. However, since some heat is also transmitted to the heat insulating layer 25, the warm-up time is slightly longer than that of Comparative Example 1-1, but the warm-up time can be significantly shortened compared to Comparative Examples 1-2 and 1-3. .

  Moreover, in Example 2, since the radiant heat of the radiation heater 32 permeate | transmits a transparent glass tube, although warm-up time becomes a little longer compared with Examples 1-1, 1-2, and 1-3, Comparative Example 2- Compared with 2 and 2-3, it is greatly shortened.

  In any of the embodiments, the warm-up time is 10 seconds or less. However, if the warm-up time can be made 10 seconds or less in this way, the user is usually hardly inconvenienced. Therefore, it is not necessary to preheat the fixing roller when the fixing device is not used in the power-on state, or the fixing roller can be kept on standby at a preheating temperature lower than that of the conventional one, thereby effectively reducing energy consumption. Can be reduced.

1 is a schematic vertical sectional view showing an example of an image forming apparatus. FIG. 3 is a cross-sectional view illustrating an example of a fixing roller. It is a cross-sectional view showing another example of a fixing roller. FIG. 10 is a cross-sectional view illustrating still another example of the fixing roller. FIG. 5 is a side view of a state where a cylindrical member of the fixing roller shown in FIG. 4 is removed to expose a heat insulating layer. It is a typical expanded sectional view of a heat insulation layer. It is a typical expanded sectional view of another heat insulation layer. Furthermore, it is a typical expanded sectional view of another heat insulation layer. FIG. 4 is a cross-sectional view illustrating a fixing device in which a fixing belt is wound around a fixing roller and another roller. It is sectional drawing which shows the manufacturing process of a fixing roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 14 Fixing device 16 Fixing roller 23 Base material 25 Heat insulation layer 26 Cylindrical member 30 Image forming means 31 Heat generating body 34 Heat resistant resin film 36 Heat resistant resin film 37 Roller 38 Fixing belt 40 Roller body AG Air layer P Recording material

Claims (11)

A fixing roller comprising a cylindrical base material made of a rigid body, a heat insulating layer disposed outside the base material, and a cylindrical member provided outside the heat insulating layer. The fixing roller according to claim 1, further comprising a heating element disposed between the heat insulating layer and the cylindrical member. The fixing roller according to claim 1, wherein the base material is formed of a transparent glass tube in which a radiation heater is disposed, and the heat insulating layer is sparsely disposed on an outer peripheral surface of the transparent glass tube. The fixing roller according to claim 1, wherein the heat insulating layer is made of a heat resistant resin film stacked in multiple layers. The fixing roller according to claim 1, wherein the heat insulating layer is formed of a heat resistant resin film having a plurality of holes stacked in multiple layers. The fixing roller according to claim 1, wherein the heat insulating layer is made of a porous heat resistant resin. The fixing roller according to claim 1, wherein the cylindrical member is made of a metal having a thickness of 0.3 mm or less. A fixing device comprising: the fixing roller according to claim 1; and a pressure member that presses the fixing roller. In place of the cylindrical member, an endless fixing belt wound around a fixing roller not having the cylindrical member and another roller is provided, and the cylindrical member is provided via the fixing belt. The fixing device according to claim 8, wherein no fixing roller and the pressure member are in pressure contact with each other. An image forming apparatus comprising: the fixing device according to claim 8; and an image forming unit that forms a toner image fixed by the fixing device on a recording material. A roller body in which a fixing roller member other than the cylindrical member is integrated, and after the cylindrical member is thermally expanded, the roller body is inserted therein, and then the cylindrical member is cooled, 8. The method of manufacturing a fixing roller according to claim 1, wherein the cylindrical member and the roller body are integrated.

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