JP2005043476A - Fixing device for image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device for image forming apparatus having high characteristic and realizing the prolongation of its life. <P>SOLUTION: The fixing device for image forming apparatus for fixing a toner image on recording material by maintaining the recording material in a heated state between a heating rotating body and a pressure rotating body and melting toner on the recording material, is characterised in that it is constituted so that at least either the heating rotating body or the pressure rotating body is set as an endless member having at least double structure consisting of an elastic body layer and a conductor layer covering around the elastic body layer, and the elastic body layer and the conductor layer are attached to each other only partially not by the entire surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device of an image forming apparatus and an image forming apparatus.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a process is required in which the toner-transferred paper is heated and pressurized to fix the toner on the paper. In this fixing process, in general, in a fixing device, paper is passed between a heating rotator and a pressure rotator (nip portion) to heat and fix toner onto the paper.
[0003]
Recently, as the heating rotator and the pressure rotator of the fixing device, a structure having a double structure of an elastic layer and a conductor layer covering the elastic layer is often used.
[0004]
[Patent Document 1]
JP 2002-49261 A
[Patent Document 2]
JP 2002-266846 A
[0005]
[Problems to be solved by the invention]
As described above, as the heating rotator and the pressure rotator of the fixing device, a structure having a double structure of an elastic layer and a conductor layer covering the elastic layer is used. However, the present inventor has thought that this double-structured rotating body has a problem of short life.
[0006]
That is, the fixing device is repeatedly heated and cooled when the image forming apparatus is used and when it is not used. According to the experiments by the present inventor, in the fixing device having the double structure rotating body as described above, deterioration due to heating / cooling and fixing failure are likely to occur, and the life is shortened. The inventor investigated the cause of this phenomenon in more detail. As a result, it has been found that this phenomenon is caused by the gas contained in the elastic body layer expanding and contracting during heating and cooling, which causes deformation and deterioration of the elastic body layer.
[0007]
The present invention is based on the recognition of such a problem, and an object thereof is to provide a fixing device for an image forming apparatus having high characteristics and a long lifetime.
[0008]
[Means for Solving the Problems]
In the fixing device of the image forming apparatus of the present invention, the recording material is maintained in a heated state between the heating rotator and the pressure rotator, and the toner on the recording material is melt-processed. A fixing device of an image forming apparatus for fixing a toner image, wherein at least one of the heating rotator and the pressure rotator includes at least one of an elastic body layer and a conductor layer covering the elastic body layer. And the elastic body layer and the conductor layer are at least partially unbonded.
[0009]
Further, the fixing device of the image forming apparatus according to the present invention maintains the recording material in a heated state between the heating rotator and the pressure rotator, melts the toner on the recording material, A fixing device of an image forming apparatus for fixing the toner image to the at least one of the heating rotator and the pressure rotator, at least two of an elastic layer and a conductor layer covering the periphery. In addition to the endless member having a heavy structure, the elastic layer is formed with a plurality of ventilation holes having at least one end opened in a direction along the axis of the endless member.
[0010]
Further, the fixing device of the image forming apparatus according to the present invention maintains the recording material in a heated state between the heating rotator and the pressure rotator, melts the toner on the recording material, A fixing device of an image forming apparatus for fixing the toner image to the at least one of the heating rotator and the pressure rotator, at least two of an elastic layer and a conductor layer covering the periphery. In addition to the endless member having a heavy structure, the elastic body layer is disposed on the outer side of the core material as a hollow body, and has a vent hole for communicating the inside and the outside with a predetermined surface of the core material. It is characterized by.
[0011]
Further, the fixing device of the image forming apparatus according to the present invention maintains the recording material in a heated state between the heating rotator and the pressure rotator, melts the toner on the recording material, A fixing device of an image forming apparatus for fixing the toner image to the at least one of the heating rotator and the pressure rotator, at least two of an elastic layer and a conductor layer covering the periphery. It is an endless member having a heavy structure, and a member having a larger end portion than the center of the coefficient of properties in the elastic layer is used.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, six embodiments will be described.
[0013]
(First embodiment)
One of the features of the image forming apparatus of the first embodiment is that, as can be seen from FIGS. 3 and 4, for example, the heating rotator 102 of the fixing device of the image forming apparatus is an elastic body made of rubber, foamed rubber, or the like. The layer 12 and the conductor layer 13 provided outside the elastic body layer 12 have a double structure, and the elastic body layer 12 and the conductor layer 13 are bonded only by a part of the bonding portion 17. It is. Thereby, deterioration of the heating rotator 102 can be suppressed and the life of the fixing device 100 can be extended.
[0014]
FIG. 1 is a diagram illustrating an image forming apparatus and a fixing device according to a first embodiment of the present invention. The image forming apparatus 1 of this embodiment is a digital copying apparatus. Similar to a general copier, the image forming apparatus 1 includes a paper feed cassette 10, a conveyance path 34, a transfer unit 30, an exposure device 40, a fixing device 100, a paper discharge roller 50, and paper discharge. A tray 60, a scanner 70, and a document glass 80 are provided. A predetermined paper P is set in the paper feed cassette 10. At the time of copying, the document is set on the document glass 80. This document is read by the scanner 70. Further, at the time of copying, the conveyance path 34 conveys the paper P to the transfer unit 30. The transfer unit 30 includes a developing device 31, a photoconductor 32, and a transfer charger 33. A latent image is formed on the photoreceptor 32 of the transfer unit 30 by the exposure device 40. Then, the toner image corresponding to the latent image is transferred onto the paper P on the transfer charger 33 of the transfer unit 30. The paper P on which the toner image is transferred is conveyed to the fixing device 100. The fixing device 100 heats and pressurizes the paper P to fix the toner on the paper P. The paper P is discharged to a paper discharge tray 60 through a paper discharge roller 50.
[0015]
The apparatus of FIG. 1 is characterized by the structure of the fixing apparatus 100. This will be described with reference to FIG.
[0016]
FIG. 2 is an enlarged view of a side surface of the fixing device 100. Note that the fixing device 100 shown in FIG. 2 is shown in a different orientation from FIG. The fixing device 100 includes a heating rotator (heat roller) 102 and a pressure rotator (press roller) 103. The fixing device 100 maintains the paper (recording material) P in a heated state between the heating rotator 102 and the pressure rotator 103, melts the toner on the paper P, and applies toner on the paper P. Fix the image. The heating rotator 102 has a cylindrical shape and is rotated around a rotation axis. The heating rotator 102 is constituted by an endless member 11 (FIG. 3) as will be described later. The diameters of the heating rotator and the pressure rotator are the same. In addition, the lower pressure rotating body 103 in the figure is also cylindrical and is rotated around the rotation axis. This pressurizing rotating body has a structure in which the core material is covered with silicon rubber, fluorine rubber, or the like. The pressurizing rotator 103 is pressed against the upper heating rotator 102 in the drawing by a pressurizing mechanism 104. The pressure rotator 103 and the heating rotator 102 are maintained so as to have a constant nip width. The upper heating rotator 102 in the figure is driven in the direction of the arrow by a drive motor (not shown). In accordance with this, the lower pressure rotating body 103 in the figure rotates in the direction of the arrow by being driven. As shown in FIG. 2, the heating rotator 102 generates heat upon receiving magnetic flux from a magnetic flux generating coil 111 disposed outside the roller. As the paper P passes through the pressure contact portion (nip portion) between the heated rotator 102 and the pressure rotator 103 that has generated the heat, the toner on the paper P is fusion-bonded and fixed.
[0017]
On the circumference of the heating rotator 102, a peeling claw 105 for peeling the paper P from the heating rotator 102 on the downstream side in the rotation direction from the contact position between the heating rotator 102 and the pressure rotator 103, heating rotation Thermistors 106 for detecting the temperature of the body 2 (a plurality of thermistors are provided in the longitudinal direction of the heating rotator), the cleaning member 107 for removing dust such as toner and paper waste offset on the heating rotator 102, and the heating rotator 2 A thermo stud 108 (at least one on the heating rotator) is provided for detecting an abnormality in the surface temperature and shutting off the heating. The thermistor 106 and the thermo stud 108 are provided at positions that are not affected by the lines of magnetic force generated from the magnetic flux generating coil 111. Among these, the thermistor 106 detects the temperature of the heating rotator 102 and adjusts the temperature of the heating rotator 102 by a temperature control device (not shown). On the other hand, a peeling claw 109 for peeling the paper P from the pressure rotator 103 and a cleaning roller 110 for removing toner are provided on the periphery of the pressure rotator 103 on the lower side in the drawing.
[0018]
FIG. 3 is a cross-sectional view of the endless member 11 constituting the heating rotator 102. The endless member 11 is formed in contact with the outer side of a cylindrical core member 16 constituting a rotating shaft, an elastic body layer 12 (for example, silicon rubber or foamed rubber) formed on the outer side of the core member. A conductive layer 13 (for example, nickel), a thin-film surface elastic layer 14 (for example, silicon rubber) formed on the outer side, and a release layer 15 (for example, PFA) formed on the outer side. More specifically, in this embodiment, iron is used as the core material 16, foam rubber is used as the elastic layer 12, nickel belt is used as the conductor layer 13, silicon rubber is used as the thin film surface elastic layer 14, and PFA is used as the release layer 15. ing. The thickness of the elastic body layer 12 is set to be much thicker than that of the conductor layer 13.
[0019]
In the heating rotator 102 of FIG. 3, the conductor layer 13 is induction-heated by the lines of magnetic force generated from the magnetic flux generating coil 111 (FIG. 2). For this reason, the heating rotator 102 generates heat near the surface. As a result, the heating rotator 102 is heated with high energy efficiency and quick start-up.
[0020]
One of the features of this embodiment is that most of the elastic body layer 12 and the conductor layer 13 are not bonded in the heating rotator 102. Hereinafter, a description will be given with reference to FIG.
[0021]
FIG. 4 is a perspective view of the heating rotator 102 and the pressure rotator 103. The heating rotator 102 is composed of an endless member 11. The length of the endless member 11 is 370 mm. Further, as shown in FIG. 4, the length of the pressure rotator 103 is shorter than that of the heating rotator 102.
[0022]
In the endless member 11 of the heating rotator 102 in FIG. 4, the elastic body layer 12 and the conductor layer 13 (see FIG. 3) are bonded only at the bonding portion 17 indicated by hatching in FIG. 4. The adhesion portion 17 is a portion 30 mm from both ends of the heating rotator 102. However, as shown in FIG. 4, a part of 30 mm from both ends is not bonded. The bonding portion 17 of the heating rotator 102 is not in pressure contact with the pressure rotator 3 and is a non-sheet passing portion through which the paper P does not pass.
[0023]
In the heating rotator 102 of the fixing device 100 of the present embodiment described above, the elastic layer 12 is provided. Therefore, the conductor layer 13 is subjected to induction heating of the conductor layer 13 by the magnetic flux generating coil 111 (FIG. 2). It is difficult for the heat generated in the diffusion to the core material 16. For this reason, the temperature of the conductive layer 13 can be raised to a temperature required for fixing in a short time, and the rise time at the time of heating can be shortened.
[0024]
Further, in the heating rotating body 102 of the fixing device 100 according to the present embodiment, the hardness of the member can be adjusted by adjusting the layer thickness of the conductor layer 13 and the elastic body layers 12 and 14 and the hardness of the material, and the nip width and peeling. The performance can be easily adjusted. Thereby, a wide nip width can be secured and stable fixing can be performed.
[0025]
Furthermore, the life of the fixing device 100 of the present embodiment can be extended. This will be described below.
[0026]
The fixing device 100 is repeatedly overheated and cooled when the image forming apparatus is used and when it is not used. The inventor has found that the fixing device having the heating rotator 102 in which the elastic body layer 12 is covered with the conductor layer 13 is likely to cause deterioration and fixing failure of the heating rotator 102 due to the heating and cooling. I knew it. The inventor investigated the cause of this deterioration in more detail. As a result, it has been found that this is because the elastic body 12 thermally expands during heating and the elastic body 12 contracts during cooling.
[0027]
Therefore, in this embodiment, as can be seen from FIG. 3 and FIG. 4, the elastic body layer 12 and the conductor layer 13 are not bonded except for the non-sheet passing portion 17. When non-adhering as described above, even if the elastic body layer 12 contracts and deforms when the heating rotator 102 is cooled, the conductor layer 13 is not affected by the deformation. For this reason, the deformation | transformation of the endless member 11 at the time of cooling can be avoided. Further, even if the elastic body layer 12 is about to expand when the heating rotator 102 is heated, the expanded gas in the elastic body easily escapes from the end of the endless member 11 to the outside, and this expansion is suppressed. Thereby, deterioration, softening, and destruction of the elastic body 12 can be prevented. As a result, the lifetimes of the heating rotator 102 and the fixing device 100 can be extended.
[0028]
Further, in this embodiment, the bonding is performed only by the bonding portion 17, but since the elastic layer 12 and the conductor layer 13 are weak in the force of shifting in the lateral direction in FIG. 4, the elastic layer 12 and the conductor The layer 13 is hardly displaced in the lateral direction in FIG.
[0029]
As described above, according to the image forming apparatus of the present embodiment, it is possible to provide a fixing device having a short rise time, a wide nip width, and a long lifetime.
[0030]
In the image forming apparatus shown in FIGS. 1 to 4 described above, in the heating rotator 102, as shown in FIG. 4, the adhesive portions 17 between the elastic layer 12 and the conductor layer 13 are both ends. However, the bonding portion 17 can be formed in a spiral shape as shown in FIG. However, also in this case, in order to make it easier for the gas in the expanded elastic body 12 to escape from the end of the endless member 11 to the outside, a part in the spiral direction is not bonded (FIG. 5).
[0031]
In the image forming apparatus of FIGS. 1 to 4, the case where the endless member 11 having a double structure of the elastic body layer 12 and the conductor layer 13 is used for the heating rotator 102 has been described. The structure can also be used for the pressure rotator 103. Thereby, since the thermal conductivity of the elastic layer is low, the amount of heat taken by the heating rotator 102 by the pressurizing rotator 103 can be kept small. In addition, the rise time of the fixing device 100 can be shortened. In addition, since the elastic layer has appropriate elasticity, the nip width can be widened. Further, the elastic layer 12 and the conductor layer 13 do not have to be bonded at all.
[0032]
In the image forming apparatus of the present embodiment, as shown in FIG. 3, the endless member 11 includes a core material 16, an elastic body layer 12, a conductor layer 13, a thin film surface elastic layer 14, and a release layer 15. And so on. However, if necessary, the thin film surface elastic layer 14 and the release layer 15 can be omitted.
[0033]
(Second Embodiment)
One of the features of the image forming apparatus of the second embodiment is that the elastic layer 12 and the conductor layer 13 of the heating rotator 102 (see FIG. 3) of the fixing device are not bonded over the entire area. is there. The configuration of the main part of the apparatus is almost the same as that of the first embodiment (FIGS. 1 to 3). Below, a different part from 1st Embodiment is demonstrated.
[0034]
FIG. 6 is a diagram showing the heating rotator 102 and the lateral shift prevention body 18 of the fixing device of the image forming apparatus according to the second embodiment of the present invention. The heating rotator 102 is composed of an endless member 11. However, in this embodiment, the elastic body layer 12 and the conductor layer 13 are not bonded at all. For this reason, as in the first embodiment, the heating and cooling of the endless member 11 are repeated, and even if the elastic body layer 12 contracts, the surface conductor layer 13 is not affected by the deformation, and the endless member 11 is deformed. Can be avoided. In addition, since the gas in the elastic layer 12 that has expanded during heating easily escapes from the end of the endless member 11 to the outside, deterioration, softening, and destruction of the elastic layer 12 can be prevented.
[0035]
However, in the heating rotator 102 of FIG. 6, since the elastic body layer 12 and the conductor layer 13 are not bonded, the elastic body layer 12 and the conductor layer 13 are laterally displaced (sliding) during use of the endless member 11. There is a risk of causing. Therefore, in order to prevent this lateral displacement, lateral displacement prevention bodies 18 are attached to both ends of the endless member 11 of this embodiment as shown in FIG. As a result, even if a lateral force is applied to the conductor layer 13 during use, the conductor layer 13 stops against the guide member 18, so that a lateral shift of the conductor layer can be prevented. The diameter of the guide member 18 is larger than that of the heating rotator 102 and is arranged around the core metal 16.
[0036]
In the fixing device of the present embodiment described above, the lateral shift prevention body 18 is attached to the endless member 11 as shown in FIG. However, as shown in FIG. 7, the lateral shift prevention body 18 can be fixed to a portion other than the endless member 11 such as the frame 19 of the fixing device. Thereby, the lateral displacement of the conductor layer 13 can be prevented as in FIG.
[0037]
Further, the modification examples as shown in FIGS. 8 to 11 can be used without providing the lateral slip prevention body 18. FIGS. 8 to 11 show a part of the heating rotator 102 and show the core metal 16, the elastic body layer 12, and the conductor layer 13. The thin-film surface elastic layer 14 and the release layer 15 (see FIG. 3) outside the conductor layer 13 are not shown.
[0038]
First, in the heating rotator 102 in FIG. 8, the length of the elastic layer 12 in the rotation axis direction is longer than the length of the conductor layer 13, and the elastic layer 12 is exposed at both end portions of the endless member 11. In this embodiment, the exposed elastic layer 12 swells and becomes larger in diameter than the conductive layer 13. As a result, even if a lateral force is applied to the conductor layer 13 during use, the conductor layer 13 is caught by the swollen portion, so that a lateral shift of the conductor layer 13 can be prevented.
[0039]
Next, the heating rotator 102 in FIG. 9 is configured such that the diameter of the central portion of the elastic layer 12 is smaller than the diameter of the end portion. Thereby, the lateral displacement of the conductor layer 13 can be prevented.
[0040]
Next, the heating rotator 102 in FIG. 10 is configured such that the diameter of the central portion of both the elastic body layer 12 and the conductor layer 13 is smaller than the diameter of the end portion. Thereby, the lateral displacement of the conductor layer 13 can be prevented. In contrast to FIG. 10, the diameters of the central portions of both the elastic body layer 12 and the conductor layer 13 may be larger than the diameter of the end portion.
[0041]
Further, in the image forming apparatus of this embodiment and the modification thereof, the case where the endless member 11 having the elastic body layer 12 and the conductor layer 13 is used for the heating rotator 102 has been described. A structure having a conductor layer can also be used for the pressure rotating body 103.
[0042]
(Third embodiment)
One of the features of the image forming apparatus according to the third embodiment is that, in the heating rotator 102 (FIG. 3) of the fixing device, as shown in FIG. A vent hole 20 that facilitates the movement of gas between the outside and the outside is formed. The configuration of the main part of the apparatus is almost the same as that of the first embodiment (FIGS. 1 to 3). Below, a different part from 1st Embodiment is demonstrated.
[0043]
FIG. 11 is a diagram illustrating a part of the heating rotator 102 of the fixing device of the image forming apparatus according to the third embodiment of the present invention. The heating rotator 102 is composed of an endless member 11. FIG. 11 shows the elastic layer 12 and the inner part of the endless member 11.
[0044]
In the endless member 11 constituting the heating rotator 102 of the present embodiment, the elastic body layer 12 and the conductor 13 are bonded over the entire region (see FIG. 3). As shown in FIG. 11, the elastic layer 12 of the endless member 11 of the present embodiment is formed with a plurality of vent holes 20 through which the gas in the elastic layer 12 can move along the rotation axis direction. In this embodiment, the vent hole 20 is open at both ends. As described above, since the vent hole 20 is provided, even if the heating rotator 102 is repeatedly heated and cooled, and the gas in the elastic body 12 expands and contracts, the gas can smoothly move through the vent hole 20. Thereby, the expansion and contraction of the elastic body 12 itself due to the expansion and contraction of the gas in the elastic body 12 can be avoided. As a result, deterioration of the heating rotator 102 can be prevented and the life of the fixing device can be extended.
[0045]
In the present embodiment, a plurality of vent holes 20 having both ends opened in the direction along the axis of the endless member are provided. However, the vent holes 20 may be vent holes having one end opened. In the scope of the claims, the vent hole is described as including both the vent hole and the vent hole. Also in this embodiment, the elastic layer 12 and the conductor layer 13 may be partially unbonded.
[0046]
In the image forming apparatus according to the present embodiment, the case where the endless member 11 having the double structure of the elastic body layer 12 and the conductor layer 13 is used for the heating rotating body 102 has been described. A structure having the same can also be used for the pressure rotator 103.
[0047]
(Fourth embodiment)
In the image forming apparatus according to the fourth embodiment, a groove 21 is provided on the surface of the elastic layer 12 as shown in FIG. The configuration of the main part of the apparatus is almost the same as that of the first embodiment (FIGS. 1 to 3). Below, a different part from 1st Embodiment is demonstrated.
[0048]
FIG. 12 is a diagram illustrating a part of the heating rotator 102 of the fixing device of the image forming apparatus according to the fourth embodiment of the present invention. The heating rotator 102 is composed of an endless member 11 (FIG. 3). FIG. 12 shows the elastic layer 12 and the inner part of the endless member 11.
[0049]
In the endless member 11 constituting the heating rotating body 102 of this embodiment, as shown in FIG. 12, both ends of the elastic body layer 12 facing the inner surface of the conductor layer 13 are disposed on the surface along the axis direction of the endless member 11. A plurality of grooves 21 whose sides are open are formed. The surface of the elastic body layer 12 where there is no groove 21 and the conductor layer 13 are bonded all over (see FIG. 3). When the endless member 11 is formed by combining the elastic body 12 and the conductor layer 13, a vent hole through which the gas in the elastic body layer 12 can move is formed between the elastic body layer 12 and the conductor layer 13 by the groove 21. . For this reason, even if heating and cooling of the heating rotator 102 are repeated and the gas in the elastic body 12 expands and contracts, the gas can be smoothly moved through the vent hole. Thereby, the expansion / contraction of the elastic body layer 12 itself due to the expansion or contraction of the gas in the elastic body layer 12 can be avoided. As a result, it can be expected that the elastic layer 12 is prevented from being deteriorated, softened, or broken.
[0050]
In the heating rotator 102 of FIG. 12 described above, a plurality of grooves 21 are provided in the direction of the rotation axis of the surface of the elastic layer 12. However, the gas may be moved more smoothly by forming the grooves 21 in the circumferential direction in addition to the grooves 21 in the rotation axis direction.
[0051]
Further, in the thermal rotator 102 of FIG. 12, grooves 21 having both ends opened are provided. However, it is also possible to provide a groove that is open at one end.
[0052]
In the image forming apparatus according to the present embodiment, the case where the endless member having the elastic body layer 12 and the conductor layer 13 is used for the heating rotating body 102 has been described. However, the image forming apparatus has the elastic body layer and the conductor layer. The structure can also be used for the pressure rotator 103.
[0053]
(Fifth embodiment)
As shown in FIG. 13, the image forming apparatus according to the fifth embodiment includes a ventilation hole formed in the core member 16 inside the elastic body layer 12 in the heating rotator 102 constituted by the endless member 11 (FIG. 3). 22 is provided. That is, a hole that facilitates gas movement between the elastic layer 12 and the outside is formed on the inner surface of the elastic layer 12. The configuration of the main part of the apparatus is almost the same as that of the first embodiment (FIGS. 1 to 3). Below, a different part from 1st Embodiment is demonstrated.
[0054]
FIG. 13 is a diagram illustrating a part of the heating rotator 102 of the fixing device of the image forming apparatus according to the fifth embodiment of the present invention. The heating rotator 102 is composed of an endless member 11. FIG. 13 shows a portion of the core member 16 constituting the rotating shaft of the endless member 11.
[0055]
In the present embodiment, as shown in FIG. 13, the core material 16 is hollow, and a plurality of vent holes 22 that communicate the inside and the outside with the side surface and the outer peripheral surface of the core material 16 are vacant. The elastic body layer 12 is arrange | positioned on the outer side of the core material 16 as this hollow body. In the heating rotator 102 of FIG. 13, heating and cooling are repeated, and even if the gas in the elastic body layer 12 expands and contracts, it passes through the core material 16 by the vent holes 22 opened in the core material 16. Can move gas smoothly. Thereby, the expansion / contraction of the elastic body layer 12 itself due to the expansion or contraction of the gas in the elastic body layer 12 can be avoided. As a result, it is possible to prevent the elastic body layer 12 from being deteriorated, softened, or broken.
[0056]
In the image forming apparatus according to the present embodiment described above, the case where the structure in which the hollow core material 16 is provided inside the elastic body layer is used for the heating rotator 102 has been described. You can also.
[0057]
(Sixth embodiment)
In the image forming apparatus according to the sixth embodiment, in the heating rotating body 102 of the fixing device, as shown in FIG. 14, the elastic body layer 12 is made of foam rubber 23 having a low firing rate at the center portion and foaming at the end portion. It is composed of two types of materials, foam rubber 24 having a high rate. The configuration of the main part of the apparatus is almost the same as that of the first embodiment (FIGS. 1 to 3). Below, a different part from 1st Embodiment is demonstrated.
[0058]
FIG. 14 is a diagram illustrating a part of the heating rotator 102 of the fixing device of the image forming apparatus according to the sixth embodiment of the present invention. The heating rotator 102 is constituted by the endless member 11. FIG. 14 shows the elastic layer 12 and the inner part of the endless member 11.
[0059]
In the heating rotator 102 of the present embodiment, the elastic body 12 and the conductor 13 are bonded over the entire region (see FIG. 3). In the present embodiment, the elastic layer 12 uses the first foamed rubber 23 with a foaming rate of 150% at the center and the second foaming with 200% higher at the end than the first foamed rubber. The rubber 24 is used to form two types of foamed rubber having different foaming rates. Thereby, the lifetime of the heating rotator 102 and the fixing device can be extended.
[0060]
That is, when heating and cooling of the heating rotator 102 are repeated, the gas in the elastic body layer 12 expands and contracts. At this time, the gas in the central portion of the elastic body layer 12 is far from the end face of the heating rotator 102 as compared with the gas in the end portion, and thus is easily trapped inside the elastic body layer 12. For this reason, the distribution of atmospheric pressure in the elastic body layer 12 at the time of heating is higher at the center than at the end. That is, in the elastic body layer 12, the force applied to the central portion is larger than that of the end portion. As a result, in the normal heating rotator 102, the central portion of the elastic body layer 12 is likely to deteriorate faster than the end portion. Therefore, in the present embodiment, the foaming rate of the first foamed rubber 23 at the center is set lower than the firing rate of the second foamed rubber 24 at the end. Thereby, the gas contained in the elastic body layer 23 in the central portion is reduced as compared with the end portion, and an increase in atmospheric pressure due to gas expansion during heating can be suppressed. As a result, the deterioration of the first foamed rubber 23 in the central portion is less likely to occur. Thereby, the lifetime of the heating rotator 102 and the fixing device can be extended.
[0061]
In the image forming apparatus of the present embodiment described above, the case where the structure in which the elastic body layer 12 is configured by two types of foamed rubber having different firing rates is used for the heating rotator 102 has been described. It can also be used for the body 103.
[0062]
In the present embodiment, the expansion ratio in the elastic body layer 12 is such that both end portions 24 are larger than the central portion 23. However, the expansion ratio in the elastic body layer 12 may be larger on the one end side than on the central portion.
[0063]
Also in this embodiment, the elastic body layer 12 and the conductor layer 13 may have a non-adhered portion in part.
[0064]
In the present embodiment, the property of the member has been described using the firing rate, but the present invention is not limited to this.
[0065]
In the embodiment of the present invention described above, the case where a copying apparatus (copy machine) is used as the image forming apparatus has been described. However, a facsimile, a printer, or the like can be used as the image forming apparatus.
[0066]
【The invention's effect】
According to the present invention, in a fixing device including a rotating body having an elastic layer and a conductor layer formed outside the elastic layer, a fixing device having high characteristics and a long life is provided. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged side view of the fixing device of the image forming apparatus according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of an endless member constituting a heating rotator of the fixing device of the image forming apparatus according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating a heating rotator and a pressure rotator of the fixing device of the image forming apparatus according to the first embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a modification of the heating rotator of the fixing device of the image forming apparatus according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a heating rotator and a guide member of a fixing device of an image forming apparatus according to a second embodiment of the present invention.
FIG. 7 is a sectional view showing a modification of the fixing device of the image forming apparatus according to the second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a modification of a part of the heating rotator of the fixing device of the image forming apparatus according to the second embodiment of the present invention.
FIG. 9 is a cross-sectional view showing a modification of the heating rotator of the fixing device of the image forming apparatus according to the second embodiment of the present invention.
FIG. 10 is a diagram illustrating a modification of a part of the heating rotator of the fixing device of the image forming apparatus according to the second embodiment of the present invention.
FIG. 11 is a diagram illustrating a part of a heating rotator of a fixing device of an image forming apparatus according to a third embodiment of the present invention.
FIG. 12 is a diagram illustrating a part of a heating rotator of a fixing device of an image forming apparatus according to a fourth embodiment of the present invention.
FIG. 13 is a diagram illustrating a part of a heating rotator of a fixing device of an image forming apparatus according to a fifth embodiment of the present invention.
FIG. 14 is a diagram illustrating a part of a heating rotator of a fixing device of an image forming apparatus according to a sixth embodiment of the present invention.
[Explanation of symbols]
P sheet
11 Endless materials
12 Elastic layer
13 Conductor layer
16 Core
17 Bonding part
18 Guide member
20 Vent
21 groove
22 Vent
30 Transfer section
100 Fixing part
102 Heating rotator
103 Pressurized rotating body

Claims (10)

Fixing of an image forming apparatus that maintains a recording material in a heated state between a heating rotator and a pressure rotator, melts the toner on the recording material, and fixes the toner image on the recording material. A device,
At least one of the heating rotator and the pressure rotator is an endless member having at least a double structure of an elastic layer and a conductor layer covering the elastic layer,
A fixing device for an image forming apparatus, wherein at least a part of the elastic body layer and the conductor layer is in an unbonded state. The fixing device for an image forming apparatus according to claim 1, wherein at least a part of the elastic layer and the conductor layer are in an adhesive state. Only one of the heating rotator and the pressure rotator has a double structure,
The length of one rotating body having a double structure in the rotation axis direction is longer than the length of the other rotating body in the rotation axis direction, and the heated rotating body and the pressure rotating body are pressed against each other in the bonded state. The fixing device for an image forming apparatus according to claim 1, wherein the fixing device is a portion that is not formed. The elastic body layer and the conductor layer are in a non-adhered state over the entire surface, and prevent the conductor layer from sliding relative to the elastic body layer at both ends of the elastic body layer and the conductor layer. The fixing device for an image forming apparatus according to claim 1, further comprising a lateral shift prevention body. Fixing of an image forming apparatus that maintains a recording material in a heated state between a heating rotator and a pressure rotator, melts the toner on the recording material, and fixes the toner image on the recording material. A device,
At least one of the heating rotator and the pressure rotator is an endless member having at least a double structure of an elastic layer and a conductor layer covering the elastic layer,
A fixing device for an image forming apparatus, wherein a plurality of air holes having at least one end opened in a direction along an axis of the endless member are formed in the elastic layer. 2. The image forming apparatus according to claim 1, wherein a groove that is open at least at one end side is formed along the axial direction of the endless member on the surface of the elastic layer facing the inner surface of the conductor layer. Fixing device. Fixing of an image forming apparatus that maintains a recording material in a heated state between a heating rotator and a pressure rotator, melts the toner on the recording material, and fixes the toner image on the recording material. A device,
At least one of the heating rotator and the pressure rotator is an endless member having at least a double structure of an elastic layer and a conductor layer covering the elastic layer,
The elastic body layer is disposed on the outer side of a core material as a hollow body, and has a vent hole that communicates the inside and the outside with a predetermined surface of the core material. . Fixing of an image forming apparatus that maintains a recording material in a heated state between a heating rotator and a pressure rotator, melts the toner on the recording material, and fixes the toner image on the recording material. A device,
At least one of the heating rotator and the pressure rotator is an endless member having at least a double structure of an elastic layer and a conductor layer covering the elastic layer,
A fixing device for an image forming apparatus, wherein the elastic layer has a property coefficient larger than that of the center of the elastic layer. The heating rotator is the endless member,
The fixing device for an image forming apparatus according to claim 1, further comprising an induction heating source for induction heating the conductor layer of the endless member. A fixing device according to any one of claims 1 to 9,
A photoreceptor on which a latent image is formed;
A transfer charger for transferring a toner image corresponding to the latent image onto the recording material;
An image forming apparatus comprising:

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