JP2001343850A - Fixing roller, fixing device for provided with the fixing roller, image forming device provided with the fixing device and method for manufacturing fixing roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the warm-up time of a fixing roller and to enhance the fixing property of a toner image and the carrying performance of recording material in a fixing device where the toner image is fixed on the recording material by making the recording material carrying the toner image pass between the heated fixing roller and a pressure roller. SOLUTION: This fixing roller 16 is constituted of base material 23 consisting of a rigid body, a heat insulating layer 25 provided on the surface of the material 23, a heating element 31 provided on the surface of the layer 25 and further a cylindrical member 26 provided on the surface of the element 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 of manufacturing the fixing roller.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile, 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. Established by the device. As the fixing device, a fixing device such as a heat fixing system, a pressure fixing system, or a solvent fixing system has been conventionally known. Among these, the fixing device of the heat fixing method 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 the thermal fixing type has a fixing roller and a pressing member pressed against the fixing roller, and heats the fixing roller to form a toner image between the fixing roller and the pressing member. Is a fixing device that fixes the toner image on the recording material by passing the recording material carrying the toner image. Further, an endless fixing belt is wound around the fixing roller and another roller, and a pressing member is pressed against the fixing belt via the fixing belt, the fixing belt is heated, and the recording material is fixed between the fixing roller and the pressing member. A fixing device of a heat fixing system for fixing the toner image on the recording material by passing the recording material through the recording medium is conventionally known.

In the above-mentioned heat fixing type fixing device,
During the fixing operation of the toner image, the fixing roller or the fixing belt needs to be at a fixing temperature suitable for fixing the toner image. Therefore, 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 a conventional fixing device, the warm-up time is long, which causes a great inconvenience to the user. There was a fear.

Therefore, it is conceivable that the fixing roller or the fixing belt can be heated to the fixing temperature in a short time by reducing the thickness of the fixing roller to reduce its heat capacity. 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, its rigidity is reduced, and the longitudinal center of the fixing roller pressed against the pressing member directly or via a fixing belt is bent or elastically crushed and deformed. As a result, wrinkles occur in the recording material conveyed between the fixing roller and the pressing member, thereby deteriorating the conveyability, and a predetermined uniform pressure and a heat amount required for fixing can be applied to the toner image. And the toner image may not be reliably fixed. As described above, in the fixing device using the fixing roller, the two requirements of shortening the warm-up time and preventing the rigidity of the fixing roller from decreasing must be satisfied at the same time. It was difficult to satisfy the requirements at the same time.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to reduce the warm-up time as compared with the prior art.
An object of the present invention is to provide a fixing roller capable of suppressing a decrease in rigidity.

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

[0008] A third object of the present invention is to provide an image forming apparatus having the above fixing device.

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

[0010]

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

At this time, it is advantageous to provide a heating element disposed between the heat insulating layer and the cylindrical member.

Further, in the fixing roller according to the first aspect, the base member is formed of a transparent glass tube in which a radiation heater is disposed, and the heat insulating layer is sparsely arranged on an outer peripheral surface of the transparent glass tube. (Claim 3).

Further, 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 laminated in multiple layers (claim 4).

Further, 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 having a plurality of stacked holes.

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.

Further, in the fixing roller according to any one of claims 1 to 6, the cylindrical member has a thickness of 0.1 mm.
Advantageously, it consists of a metal of 3 mm or less (claim 7).

Further, according to the present invention, in order to achieve the second object, there is provided a fixing device comprising the fixing roller according to any one of claims 1 to 7 and a pressing member which presses against the fixing roller. It is proposed (claim 8).

Further, in the fixing device according to the present invention, an endless fixing belt wound around a fixing roller having no cylindrical member and another roller is used instead of the cylindrical member. A fixing roller having no cylindrical member and the pressing member may be configured to be in pressure contact with the pressing member via the fixing belt.

Further, according to the present invention, in order to achieve the third object, 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 comprising:
0).

Further, in order to achieve the fourth object, the present invention provides a roller body in which a fixing roller member other than a cylindrical member is integrated, and further comprises a step of thermally expanding the cylindrical member. 8. The fixing roller according to claim 1, wherein the roller member is inserted therein, and then the cylindrical member is cooled to integrate the cylindrical member and the roller member. A method is proposed (claim 11).

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 in FIG. 1 includes image forming means 30 for forming a toner image on a recording material,
A fixing device 14 for fixing a toner image on a recording material and a recording material feeding device 7 for feeding the recording material to the image forming means 30 are provided. First, the configuration and operation of the image forming means 30 will be clarified.

The image forming means 30 illustrated in FIG. 1 has a drum-shaped photosensitive member 2 as an example of an image carrier disposed inside the image forming apparatus main body 1, and when a printing operation is performed, the photosensitive member 2 is exposed to light. The body 2 is driven to rotate counterclockwise in FIG. At this time, the surface of the photoreceptor is uniformly charged to a predetermined polarity by the charging device 3, and the charged surface is irradiated with a light-modulated laser beam 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 photoconductor.

The electrostatic latent image is visualized as a toner image by the developing device 5. Developing device 5 shown here
Has a developing case 18 containing a powdered developer D and a developing roller 6 for carrying and transporting the developer, and the toner of the carried developer is electrostatically applied to the surface of the photoreceptor. Then, the electrostatic latent image is visualized as a toner image.

The image forming means 30 of this embodiment includes a transfer roller 11 which is an example of a transfer device for transferring a toner image formed on the photoreceptor 2 onto a recording material as described later, A cleaning device 12 for removing transfer residual toner adhering to the body surface, and a separation claw 1 for separating a recording material from a photoreceptor
5 is provided.

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

The recording material feeding device 7 includes a main body 1 of the image forming apparatus.
Has a cassette 8, a feeding roller 9, and a pair of registration rollers 10 arranged below the recording material P. The recording material P stored in the cassette 8 is fed one by one by the rotation of the feeding roller 9. The leading edge of the fed recording material P hits the pair of registration rollers 10 and temporarily stops.
Next, the registration roller 10 starts rotating at a predetermined timing, whereby the recording material is transferred to the transfer roller 11 at a timing matching with the toner image formed on the photoconductor 2.
Is sent toward the transfer portion in the area between the photoconductor 2 and the photosensitive member 2 (in the direction of arrow A). When the recording material passes through the transfer section, the toner image on the photoreceptor surface is transferred to the recording material surface. As the recording material P, paper, a resin sheet, a resin film, or the like is used.

The untransferred toner adhering to the surface of the photoconductor without being transferred to the recording material P 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 photoreceptor 2 by the operation of the separating device including the static elimination needle 15.

Next, an 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.
These rollers 16 and 17 rotate in the directions indicated by arrows in FIG. 1 while being pressed against each other. The recording material separated from the photoreceptor 2 by the static elimination 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 the heat received from the fixing roller 16, In addition, pressure is received from the fixing roller 16 and the pressure roller 17. Thus, 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 by a discharge roller pair 19 onto a discharge tray 20 formed by an outer cover of the image forming apparatus main body 1.

Further, the fixing device 14 of this embodiment 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 provided in parallel with the fixing roller 16 and has a metal core 21 made of a rigid metal and an elastic layer 22 made of, for example, silicone rubber fixed to the outer peripheral surface thereof. The elastic layer 22 is elastically deformed in 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.

While the basic structure and operation of the image forming apparatus shown in FIG. 1 have been described above, the fixing device 14 of the image forming apparatus, particularly the fixing roller 16 thereof, is configured in various modes as described below. Is done.

FIG. 2 is an enlarged sectional view showing the fixing roller 16 of the first example. Fixing roller 16 exemplified here
Is a cylindrical base member 23 made of a rigid body, a heat insulating layer 25 disposed radially outside the base member 23, and a heat insulating layer 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 outer peripheral surface of the heat insulating layer 25 is provided on the outer peripheral surface of the heat insulating layer 25. The cylindrical member 26 is directly fixed, and these elements 23, 2
5, 26 are arranged concentrically.

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

The heat insulating layer 25 is made of, for example, a resin having excellent heat resistance. Specifically, the heat insulating layer 25 made of polyimide is particularly excellent, but in addition, polyimide amide, aramid, polybenzobisoxazole,
The heat insulating layer 25 can be made of an organic or inorganic material such as polybenzimidazole, liquid crystal polyester, polyphenylene sulfide, silicone, or alumina, or a composite material of these materials and a material including polyimide.

The cylindrical member 26 is made of a resin or a metal having a small thickness. In particular, a cylindrical member 26 having a small heat capacity and made of a metal having a thickness of 0.3 mm or less, preferably 0.2 mm or less is used. It is advantageous. A release layer 29 made of, for example, a fluorine-based resin is provided on the outer peripheral surface of the cylindrical member 26 so that the toner on the recording material P is difficult to transfer.
Is formed, but the release layer 29 may be omitted.

The above-mentioned fixing roller 16 is heated by an appropriate heating means, and for example, as shown in FIG.
Is brought into contact with the outer peripheral surface of the fixing roller 16, and the heater 27 is rotated by the rotation of the fixing roller 16.
2 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 be heated by radiation, convection, or induction heating means from outside the fixing roller 16.

According to the above-described fixing roller 16, the fixing roller 16 and the heating roller 28 start to rotate when the power of the image forming apparatus is turned on, and when the heater 27 is energized, the heat is fixed via the heating roller 28. The heat is transmitted to the cylindrical member 26 of the roller 16 and is heated. This cylindrical member 26 has a small heat capacity, and further, the heat insulating layer 2
5, the heat of the cylindrical member 26 is not easily transmitted to the base member 23. Therefore, in a very short time, the cylindrical member 26
Can be raised to a temperature suitable for fixing the toner image, and the warm-up time can be reliably reduced.

Further, the fixing roller 16 and the pressure roller 17
Are rotated in the direction indicated by the arrow in FIG.
When the recording material is passed between the fixing rollers 6 and 17 to perform the fixing operation of the toner image, the fixing roller 16 has a rigid base material 23 and a heat insulating layer 25 on the center side thereof. Numeral 16 indicates great rigidity. In particular, since the inside of the base member 23 is formed in a hollow cylindrical shape, its rigidity is significantly increased as compared with a case where a base member composed of a solid shaft manufactured using the same amount of material is employed. Can be.

As described above, since the rigidity of the fixing roller 16 can be increased, the central portion in the longitudinal direction of the fixing roller 16 pressed by the pressing roller 17 is largely bent or deformed. However, the nip N (FIG. 1) required for fixing the toner image can be secured, and the uniform pressure and heat 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 the fixing property), and the problem that the recording material conveyed while being sandwiched between the fixing roller 16 and the pressure roller 17 can be prevented from being wrinkled (recording material) Improvement of transportability).

The fixing roller 16 of the second example shown in FIG.
Has a heating element 31 disposed between the heat insulating layer 25 and the cylindrical member 26, and the surface of the heating element 31 on the side of the cylindrical member 26 has an electrically insulating property such as a polyimide film. The insulating layer 33 shown is laminated. Other configurations are the same as those of the fixing roller shown in FIG. Heating element 31
Is constituted by a resistor made of, for example, a metal sheet or film, and heat is applied to the heating element 31 to cause the heating element 31 to generate heat.
The cylindrical member 26 of No. 6 is heated. With this configuration,
The heat capacity of the cylindrical member 26 on the outer side is small, and the heat of the cylindrical member 26 is hardly transmitted to the side of the base member 23 by the heat insulating layer 25. Further, the rigidity of the fixing roller 16 is increased by the base member 23 and the heat insulating layer 25. Figure 2
The warm-up time can be shortened, and the fixing property and the transportability of the recording material, that is, wrinkles on the recording material can be prevented, just like the fixing roller shown in FIG.

The fixing roller 16 of the third example schematically shown in FIG. 4 has a substrate 23 made of a transparent glass tube, and a radiation heater 32 made of, for example, a halogen heater is disposed inside the tube. A heat insulating layer 25 made of the above-described material is provided around the substrate 23 made of a transparent glass tube. The heat insulating layer 25 of this example is provided on the outer peripheral surface of the substrate 23 made of a transparent glass tube. They are 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 taped. The tape-shaped heat-insulating layer 25 is spirally wound with a gap G around the surface of a cylindrical substrate 23 made of a transparent glass tube. The heat insulating layer 25 is sparsely arranged on the outer peripheral surface of the transparent glass tube with a gap G therebetween. 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 there is no difference in the point that a heating element is not provided from the fixing roller shown in FIG.

In the third fixing roller 16 described above,
The radiant heat generated in the radiant heater 32 by energizing the radiant heater 32 passes through the substrate 23 made of a transparent glass tube,
Furthermore, it reaches the cylindrical member 26 through the gap G between the tape-shaped heat insulating layers 25 and is absorbed therein, whereby the cylindrical member 26 is heated. Also in 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 transferred by the heat insulating layer 25.
3 to the side of the cylindrical member 2
6 can be quickly raised to the fixing temperature to reduce the warm-up time. The heat insulation layer 25 is
Since it is located sparsely with a gap G above, radiant heat from the radiant heater 32 is less likely to be absorbed by the heat insulating layer 25, and reaches the cylindrical member 26 efficiently through the gap G. Can be hardly transmitted to the side of the base material 23 by the heat insulating layer 25.
Further, the rigidity of the fixing roller 16 can be increased by the cylindrical base member 23 made of a transparent glass tube and the heat insulating layer 25, thereby improving the fixing property of the toner image as in the case of the above-described example. This can be conveyed without increasing wrinkles in the recording material, and the conveyance of the recording material can be enhanced.

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

It should be noted that the second and the third shown in FIGS.
In the case of the fixing roller 16 of the example, the fixing roller 16
At the time of warm-up (rising) in which the temperature of the cylindrical member 26 is raised to the fixing temperature, the fixing roller 16 may be kept stopped or may be rotated.

The heat insulating layer 2 of the fixing roller 16 in each of the above-described examples.
As 5, a single-layer film or sheet made of the material exemplified above may be used, but as schematically shown in FIG. 6, a heat-resistant film 34 having a thickness t of, for example, about 50 μm is used. It is advantageous to use multilayers.
As the film 34, for example, a film made of the resin exemplified above can be used. As described above, when the heat insulating layer 25 is formed of the heat-resistant resin film 34 stacked in multiple layers, a minute air layer AG is formed between the films, whereby the elasticity can be remarkably improved.

As shown schematically in FIG. 7, the heat-resistant film 3 made of the resin exemplified above is used.
6 can be used in multiple layers, and the heat insulating layer 25 in which the holes 35 are formed in the respective films 36 can be used. As described above, when the heat insulating layer 25 made of the heat resistant resin film 36 having the holes 35 stacked in multiple layers is used, the contact area of each film 36 is reduced, and more air is present inside the heat insulating layer 25. Therefore, the heat insulating property can be further improved, and the time for forming the fixing roller 16 can be further reduced.

Further, as schematically shown in FIG. 8, a heat insulating layer 25 in the form of a sheet in which a number of voids are formed by sintering a polyimide powder may be used. Thus, the heat insulating layer 2 made of porous heat-resistant resin
When 5 is used, more air can be made to exist in the inside, and the heat insulation can be more reliably improved.

The fixing device 14 shown in FIG. 1 has the above-described fixing roller 16 and the pressing roller 17 which is an example of a pressing member which presses against the fixing roller 16. Instead of the roller 17, for example, a pressure member made of a pressure belt that is driven by being wound around a plurality of rollers is used, and the pressure belt is pressed against the fixing roller 16, and the fixing roller 16 and the pressure belt In this case, a recording material may be passed through, and at this time, the toner image on the recording material may be fixed by the action of heat and pressure.

Further, the fixing roller 1 having the above-described respective configurations is used.
6, the cylindrical member 26 may be omitted, and the fixing belt may be wound around a fixing roller having no cylindrical member and another roller to form a fixing device.

FIG. 9 shows that the fixing roller 16 obtained by removing the cylindrical member 26 from the fixing roller 16 shown in FIG. 2 and another roller 37 have a thickness of, for example, 0.2 mm or less, preferably 0 mm. Endless metal fixing belt 3 of 1 mm or less
8 shows an example of a fixing device 14 in which a pressure roller 17, which is an example of a pressure member, is pressed against a fixing roller 16 via a fixing belt 38. In a space inside the fixing belt between the fixing roller 16 and the roller 37, a heater 41 made of, for example, a halogen heater is arranged.
The fixing roller 16 and the fixing belt 38 are heated by energizing the power supply. It is preferable that a release layer 39 made of, for example, a fluororesin is formed on the surface of the fixing belt 38 so as to prevent an offset in which toner adheres to the surface of the fixing belt 38. Thus, instead of a cylindrical member,
An endless fixing belt 38 wound around the fixing roller 16 having no cylindrical member and another roller 37 is provided, and the fixing roller 16 having no cylindrical member is provided via the fixing belt 38. The fixing device 14 is configured so that the pressure member and the pressure member are pressed against each other. Also in the fixing device 14, at the time of warm-up, while the fixing roller 16, the roller 37, the fixing belt 38, and the pressure roller 17 are rotated, the fixing roller 16 is energized by energizing the heater 41.
When the fixing belt 38 is heated, the temperature can be raised to the fixing temperature at an early stage, and the warm-up time can be shortened. Moreover, due to the rigid base material 23,
The overall rigidity of the fixing roller 16 can be increased, and the fixing property of the toner image during the fixing operation and the transport property of the recording material can be improved.

The roller 37 is also made of a rigid rigid cylindrical base material 23A and a heat insulating layer 25A fixed to the outer peripheral surface thereof.
, It is difficult for the heat of the fixing belt 38 to transfer to the roller 37, and the warm-up time of the fixing belt 38 can be further reduced.

A fixing belt similar to the fixing device 14 shown in FIG. 9 is formed by winding a fixing belt around a fixing roller obtained by removing the cylindrical member 26 from the fixing roller 16 shown in FIGS. The above-described operation and effect can also be achieved by such a fixing device. 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 above-described fixing rollers 16 or a fixing device 14 having the fixing rollers 16 and a toner image fixed by the fixing device 14 on a recording material P. FIG. 1 shows an example of an image forming apparatus having an image forming means 30 for performing the image forming process. However, as the image forming means, various types of image forming means other than those shown in FIG. 1 can be employed.

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

As shown in FIG. 10A, a cylindrical member 26 is prepared, and the cylindrical member 26 is heated and expanded as shown in FIG. 10B (the direction of expansion is indicated by an arrow). ), To increase its diameter. On the other hand, members of the fixing roller other than the cylindrical member 26 are integrated to form a roller body 40, and the roller body 40 is inserted into the expanded cylindrical member 26 as shown in FIG. Next, as shown in FIG. 10D, the cylindrical member 26 is cooled to reduce its diameter (the contraction direction is indicated by an arrow), and the cylindrical member 26 and the roller body 40 are integrated. Each member constituting the fixing roller 16 may be fixed by an adhesive. 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 of the above-described examples is not limited to the illustrated example, but may include heat conduction from outside, radiation, convection, and induction heating means from at least one of the outside and inside. Etc. can be appropriately adopted.

[0060]

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

The fixing roller 16 used in each embodiment and the comparative example
The cylindrical member 26 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 members 26 are all made of aluminum, and their thickness is as described later. The pressure roller 17 that is in pressure contact with the fixing roller 16 is provided with an elastic layer 22 made of silicone rubber on a metal core 21, and presses each end in the longitudinal direction with a force of 120 N to apply the pressure. The roller 17 was pressed against the fixing roller 16 so that the contact portion between the rollers 16, 17, that is, the width of the nip N was about 9 mm. The target temperature of the surface of the fixing roller 16 is set to 160 ° C., and 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 fixing roller 16 controls the temperature and rotates the recording material made of paper at a speed of 330 mm / sec.
And the pressure roller 17 to fix the toner image on the recording material. Table 1 shows the results of the evaluation of the warm-up time when 1200 W is supplied, the transportability of the recording material, and the fixability of the toner image.

The specific structure of the fixing roller 16 and the heating method in each of the examples and comparative examples shown in Table 1 are as follows. (1) Example 1-1 (see FIG. 3) Cylindrical member 26: 0.2 mm thick aluminum. 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 inside the insulating layer 33. The heating element 31 was heated. A tape-shaped heating element 31 was spirally wound around the outer peripheral surface of the heat insulating layer 25 at intervals in the axial direction of the fixing roller 16. Heat insulation layer 25: 0.2 mm thick polyimide molded product. Substrate 23: 2 mm thick aluminum. (2) Example 1-2 (see FIG. 3) Cylindrical member 26: Same as Example 1-1. Heating method: same as in Example 1-1. Insulation layer 25: 50 μm thick polyimide film 4
Those superimposed on layers (see FIG. 6). Substrate 23: Same as in Example 1-1. (3) Example 1-3 (see FIG. 3) Cylindrical member 26: Same as Example 1-1. Heating method: same as in Example 1-1. Insulating layer 25: A polyimide film having a thickness of 50 μm, a hole having an area ratio of 50% was formed, and the film was superposed on four layers (see FIG. 7). Substrate 23: Same as in Example 1-1. (4) Example 1-4 (see FIG. 3) Cylindrical member 26: Same as Example 1-1. Heating method: same as in 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 in Example 1-1. (5) Comparative Example 1-1 Cylindrical Member 26: Same as Example 1-1. Heating method: same as in Example 1-1. Heat 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: same as in Example 1-1. Heat insulation layer: None Base material: None (7) Comparative example 1-3 Cylindrical member 26: 1.5 mm thick aluminum. Heating method: same as in Example 1-1. Heat insulation layer: None Base material: None (8) Example 2 (see FIGS. 4 and 5) Cylindrical member 26: 0.2 mm thick aluminum. Heating method: electricity is supplied to the halogen heater 32 arranged at the center of the substrate 23. Insulating layer 25: Four layers of polyimide films each having a width of 5 mm and a thickness of 50 μm are spirally wound around the outer peripheral surface of the substrate 23 with a gap G of 15 mm. Substrate 23: A transparent glass tube having a thickness of 2 mm. (9) Comparative Example 2-1 Cylindrical Member 26: Same as Example 2. Heating method: same as in Example 2. Heat 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: same as in Example 2. Insulation layer: None Base material: None (11) Comparative Example 2-3 Cylindrical member 26: 1.5 mm thick aluminum. Heating method: same as in Example 2. Insulation layer: None Base material: None (12) Example 3 (see FIG. 9) Fixing belt: made of stainless steel having a thickness of 0.1 mm. Heating method: The halogen heater 41 disposed inside the fixing belt 38 is energized. Insulating layer 25: Polyimide powder is made of porosity 60%, thickness of 0.1%.
Sintered to 2 mm (see FIG. 8). Substrate 23: 2 mm thick aluminum.

[0063]

[Table 1]

In the third embodiment, when the fixing roller 16 and the fixing belt 38 warm up, the fixing roller 16 and the fixing belt 38 are rotated together. In other cases, the fixing roller 16 is stopped at the time of warming up. In Table 1, "O" indicates that no wrinkling occurred in the recording material, that the recording material had good transportability, and that the fixability of the toner image was good, and that "X" did not. Indicates that

As can be seen from Table 1, in the case of the comparative example having no base material 23, when the thickness of the cylindrical member 26 is smaller than 2 mm, the transportability of the recording material cannot be satisfied. This is because the rigidity of the fixing roller 16 is insufficient.
This is because the central portion in the longitudinal direction is bent or crushed and deformed, and the transportability of the recording material is deteriorated. In particular, in Comparative Examples 1-1 and 2-1 since the thickness of the cylindrical member 26 was extremely thin, 0.2 mm, the fixing roller 16 was completely deformed, and wrinkles occurred in all the recording materials. In addition, the fixability of the toner image cannot be satisfied. 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 was as large as 2 mm, the transportability of the recording material and the fixing property of the toner image were satisfied, but compared with the Examples. Significantly longer warm-up times are required. When such a fixing roller 16 is used, although the power is turned on, it is necessary to preheat the fixing roller 16 to a standby temperature lower than the fixing temperature during a standby period in which a printing operation is not performed. However, such preheating inevitably leads to a problem of consuming a large amount of energy even when the fixing device is not used.

In Examples 1-1, 1-2 and 1-3, the cylindrical member 26 is heated by the heat transmission from the heating element 31, and the heat of the cylindrical member 26 is Can be prevented, so that the warm-up time can be reduced. However, since some heat is transmitted to the heat insulating layer 25, the warm-up time is slightly longer than that of the comparative example 1-1, but the warm-up time can be significantly reduced as compared with the comparative examples 1-2 and 1-3. .

In the second embodiment, the radiation heat of the radiant heater 32 is transmitted through the transparent glass tube.
Although the warm-up time is slightly longer than that of Comparative Examples 2-2 and 1-3, the warm-up time is much shorter than that of Comparative Examples 2-2 and 2-3.

In each of the embodiments, the warm-up time is 10 seconds or less. However, if the warm-up time can be reduced to 10 seconds or less, the user does not usually feel inconvenience. 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 before, thereby effectively reducing energy consumption. Can be reduced.

[0070]

According to the first and second aspects of the present invention, since the heat insulating layer is provided between the base material of the fixing roller and the cylindrical member, the warm-up time of the cylindrical member can be reduced, and The rigidity of the fixing roller can be increased by the cylindrical base material, so that the fixing property of the toner image and the conveying property of the recording material can be improved.

According to the third aspect of the present 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 reduced, and the cylindrical base member can be shortened. The rigidity of the fixing roller can be increased by the material, so that the fixing property of the toner image and the conveying property of the recording material can be improved.
Further, since the substrate is made of a transparent glass tube and the heat insulating layer is sparsely arranged, radiant heat from the radiant heater in the substrate can be efficiently transmitted to the cylindrical member.

According to the fourth aspect of the present invention, since an air layer is formed between the heat-resistant resin films, the heat insulating effect of the heat insulating layer can be enhanced.

According to the fifth aspect of the present invention, since a heat insulating layer in which a plurality of heat-resistant resin films with holes are stacked is used,
A large amount of air exists in the heat of the heat-insulating layer, so that the heat-insulating property of the heat-insulating layer can be further improved.

According to the sixth aspect of the present invention, since the heat insulating layer is porous, a large amount of air is present in the heat insulating layer, whereby the heat insulating property of the heat insulating layer can be further improved.

According to the seventh aspect of the invention, the heat capacity of the cylindrical member can be extremely reduced, so that the warm-up time can be more reliably reduced.

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 reduced, and the recording material transporting property and the toner fixing property are improved.

According to the tenth aspect of the present invention, it is possible to provide an image forming apparatus provided with a fixing device in which the warm-up time is shortened, the recording material transporting property and the toner fixing property are improved.

According to the eleventh aspect, the fixing roller can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing an example of an image forming apparatus.

FIG. 2 is a cross-sectional view illustrating an example of a fixing roller.

FIG. 3 is a cross-sectional view illustrating another example of a fixing roller.

FIG. 4 is a cross-sectional view showing still another example of the fixing roller.

FIG. 5 is a side view of the fixing roller shown in FIG. 4 in a state where a cylindrical member is removed to expose a heat insulating layer.

FIG. 6 is a schematic enlarged sectional view of a heat insulating layer.

FIG. 7 is a schematic enlarged sectional view of another heat insulating layer.

FIG. 8 is a schematic enlarged sectional view of still another heat insulating layer.

FIG. 9 is a cross-sectional view illustrating a fixing device in which a fixing belt is wound around a fixing roller and another roller.

FIG. 10 is a cross-sectional view illustrating a manufacturing process of the fixing roller.

[Explanation of symbols]

 14 Fixing Device 16 Fixing Roller 23 Base Material 25 Heat Insulating Layer 26 Cylindrical Member 30 Image Forming Means 31 Heating Element 34 Heat Resistant Resin Film 36 Heat Resistant Resin Film 37 Roller 38 Fixing Belt 40 Roller Body AG Air Layer P Recording Material

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jun Yura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Jun Nakato 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H033 AA25 AA30 AA31 BA05 BA11 BB03 BB12 BB14 BB19 BB31 3K058 AA02 BA18 CA23 CA61 DA02 GA06

Claims (11)

[Claims] 1. A fixing roller comprising: a rigid cylindrical base material; a heat insulating layer disposed outside the base material; and a cylindrical member provided outside the heat insulating layer. 2. The fixing roller according to claim 1, further comprising a heating element disposed between the heat insulating layer and the cylindrical member. 3. The transparent glass tube according to claim 1, wherein the substrate 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. Fixing roller. 4. The fixing roller according to claim 1, wherein the heat-insulating layer is made of a heat-resistant resin film laminated in multiple layers. 5. The fixing roller according to claim 1, wherein the heat-insulating layer is formed of a heat-resistant resin film having holes stacked in multiple layers. 6. The fixing roller according to claim 1, wherein the heat insulating layer is made of a porous heat-resistant resin. 7. 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. 8. A fixing device comprising: the fixing roller according to claim 1; and a pressing member that presses the fixing roller. 9. An endless fixing belt wound around a fixing roller having no cylindrical member and another roller in place of the cylindrical member, and a cylindrical member is provided via the fixing belt. The fixing device according to claim 8, wherein the fixing roller having no shape member and the pressing member are in pressure contact with each other. 10. A fixing device according to claim 8, wherein:
An image forming apparatus comprising an image forming means for forming a toner image fixed by the fixing device on a recording material. 11. A roller body in which a fixing roller member other than a cylindrical member is integrated, and after the cylindrical member is thermally expanded, the roller body is inserted therein, and then the cylindrical member is formed. 8. The method for manufacturing a fixing roller according to claim 1, wherein the roller is cooled to integrate the cylindrical member and the roller body.