JP2008112097A - Endless belt, manufacturing method of the same, fixing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt which can be suppressed from being broken at the end portion in the axial direction thereof and to provide a fixing device in which the endless belt is mounted and an image forming apparatus in which the fixing device is mounted. <P>SOLUTION: The endless belt has a cylindrical base material layer and a surface cover layer laminated on the outer circumferential surface of the cylindrical base material layer and is configured so that at least a part of both end surfaces in the axial direction of the cylindrical base material layer is covered by the surface cover layer. The fixing device uses the endless belt and the image forming apparatus uses the endless belt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endless belt, an endless belt manufacturing method, a fixing device, and an image forming apparatus.

2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus is provided with a fixing device for fixing toner transferred onto a recording medium onto the recording medium.
As such a fixing device, a fixing device including a fixing roll having a heating source and an endless belt which is provided in pressure contact with the fixing roll and rotates with the fixing roll is known (for example, a patent) Reference 1).

  In such a fixing device, a pressure member such as a pressure member is provided on the inner circumferential side of the endless belt, and the endless belt and the fixing roll are pressed by the pressure member toward the fixing roll. And press. By passing the recording medium through a pressurized area between the endless belt and the fixing roll, unfixed toner on the recording medium is fixed on the recording medium.

  As a problem associated with such a fixing device using an endless belt, there is a problem that the end of the endless belt in the axial direction is damaged due to the bias of the endless belt during traveling. Such a problem is caused by the load applied to the endless belt due to the recording medium passing between the endless belt and the fixing roll, the bias of the pressure distribution applied to the pressure region between the endless belt and the fixing roll, and the like. It is considered that the endless belt meanders in the fixing device, and the endless belt axially contacts the various members in the fixing device repeatedly.

If the end of the endless belt is broken as a result of a break in the axial end, the endless belt may be broken.
JP-A-8-262903

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and an endless belt capable of suppressing breakage of an axial end, a method of manufacturing the endless belt, a fixing device equipped with the endless belt, and the fixing device An object of the present invention is to provide an image forming apparatus equipped with

  The above-mentioned subject is achieved by the following present invention. That is, the endless belt of the present invention has a cylindrical base material layer and a surface coating layer laminated on the outer peripheral surface of the cylindrical base material layer, and at least axial end faces of the cylindrical base material layer. A part is covered with the surface coating layer.

  It is preferable that the axial end surface of the cylindrical base material layer covers at least 20% or more of the thickness of the cylindrical base material layer with the surface coating layer.

  The endless belt manufacturing method of the present invention includes a first application step of applying a film-forming resin solution to the outer peripheral surface of a core body to form a cylindrical resin film on the core body, and forming the endless belt on the core body. A drying step of drying the cylindrical resin film, and a groove forming step of forming grooves along the circumferential direction of the cylindrical resin film at both axial ends of the cylindrical resin film dried by the drying process; A second application step of applying a surface coating resin solution to an outer peripheral surface of the cylindrical resin film in which the groove is formed by the groove forming step to form a surface coating layer on the cylindrical resin film; and the cylinder A heat-firing step of heat-firing the resin-like resin film and the surface coating layer to form a laminate of the cylindrical base material layer and the surface coating layer on the outer peripheral surface of the core, and the laminate and the core And a separation step of separating.

  The groove part preferably has a depth dimension of 20% or more and 90% or less of the thickness of the cylindrical resin film.

  The fixing device of the present invention includes a fixing member rotatably disposed, a cylindrical base material layer, and a surface coating layer laminated on an outer peripheral surface of the cylindrical base material layer, and the cylindrical base material layer. An endless belt that covers at least a part of both end surfaces in the axial direction with the surface coating layer and sandwiches and conveys the recording medium to and from the fixing member, and is disposed on the inner peripheral side of the endless belt, Or a pressurizing unit that applies pressure to the fixing member via the endless belt and the recording medium.

  The image forming apparatus of the present invention includes an image carrier, latent image forming means for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image with toner to form a toner image on the image carrier. Developing means for forming the toner image, transfer means for transferring the toner image on the image carrier to a recording medium, a fixing member rotatably arranged, a cylindrical base material layer, and an outer periphery of the cylindrical base material layer A surface covering layer laminated on the surface, and at least a part of both axial end surfaces of the cylindrical base material layer are covered with the surface covering layer, and the recording medium is sandwiched and conveyed with the fixing member. An endless belt, and a pressurizing unit that is disposed on an inner peripheral side of the endless belt and applies pressure to the fixing member via the endless belt or the endless belt and the recording medium. Toner image on the recording medium to which the toner image has been transferred And a, a fixing device for fixing on the recording medium.

  According to the endless belt, the endless belt manufacturing method, the fixing device, and the image forming apparatus of the present invention, the endless belt capable of suppressing damage at both ends in the axial direction, the endless belt manufacturing method, and the fixing device including the endless belt And an image forming apparatus including the fixing device.

  Embodiments of a fixing device according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, a fixing device 10 according to an embodiment of the present invention includes a fixing roll 12 as a fixing member, an endless belt 14, and a pressing member 16 as a pressing unit.

  The outer peripheral surface of the endless belt 14 is disposed in contact with the outer peripheral surface of the fixing roll 12 in the axial direction of the fixing roll 12. The endless belt 14 and the fixing roll 12 are provided so that the axial directions thereof are the same. The pressure member 16 is long and long in the axial direction of the endless belt 14, and is disposed on the inner peripheral surface side of the endless belt 14. The pressure member 16 is disposed so as to apply pressure from the inner peripheral surface side of the endless belt 14 to the fixing roll 12 via the endless belt 14, and pressure is applied between the pressure member 16 and the endless belt 14. Forming a pressure region.

  A recording medium K carrying unfixed toner T is conveyed to a pressure region between the endless belt 14 and the fixing roll 12 by a conveyance mechanism (not shown), and the recording medium K is transferred to the endless belt 14 and the fixing roll 12. As a result, the toner T is fixed on the recording medium K.

  The fixing roll 12 has a cylindrical core 12A, an elastic layer 12B coated on the surface of the core 12A, and a release layer 12C coated on the surface of the elastic layer 12B. A heating source 18 is provided inside 12A.

  The material of the core 12A is not particularly limited as long as it is a material having excellent mechanical strength and good thermal conductivity. For example, metals, alloys such as aluminum, SUS, iron, copper, and brass are used. Can be mentioned.

  The material of the elastic body layer 12B can be appropriately selected from known materials for the elastic body layer 12B. For example, silicone rubber, fluorine rubber, or the like can be used. The elastic layer 12B is formed on the surface of the core 12A by a known method, and there is no particular limitation on the method, and for example, a known injection molding method or a coating method can be employed. .

  The release layer 12C is provided in order to suitably prevent unfixed toner on the recording medium K from adhering to the fixing roll 12 side. There is no particular limitation as long as it exhibits moderate releasability, and for example, fluororubber, silicone rubber, fluororesin and the like are used.

  The heating source 18 is not particularly limited as long as it has a shape and structure that can be accommodated inside the core 12A as shown in FIG. 1 or a shape and structure that can be provided outside the core 12A. Can be appropriately selected depending on the purpose, and for example, a halogen lamp or the like can be used. The surface temperature of the fixing roll 12 heated by the heating source 18 is provided with a temperature sensor (not shown) for detecting the temperature so as to come into contact with the surface of the fixing roll 12, for example. Based on the result, the heating temperature of the fixing roll 12 by the heating source 18 may be adjusted so that the surface temperature of the fixing roll 12 becomes a predetermined temperature.

  There is no restriction | limiting in particular as such a temperature sensor, For example, a thermistor, a thermocouple, etc. are used. Moreover, there is no restriction | limiting in particular as a control means, For example, a temperature controller, a computer, etc. can be used.

  The pressure member 16 includes a support member 16B and a pad 16A. The pad 16A is made of silicone rubber, fluorine rubber, or the like. The support member 16B is a member for supporting the pad 16A.

  One end of an urging member (not shown) such as a coil spring is connected to the support member 16B. The other end of the urging member is supported by a metal pressure contact member (not shown). The pressure contact member is provided with a guide member 19 for supporting the travel of the endless belt 14 in the circumferential direction via a support member (not shown).

The pad 16A is biased by a biasing member through a support member in a direction approaching the outer peripheral surface of the fixing roll 12 at a predetermined pressure (for example, 1 to ² kg / cm ² ). The pressure member 16 is long and long in the axial direction of the endless belt 14, and is disposed on the inner peripheral surface side of the endless belt 14. The pressure member 16 is disposed so as to apply pressure from the inner peripheral surface side of the endless belt 14 to the fixing roll 12 via the endless belt 14, and pressure is applied between the pressure member 16 and the endless belt 14. Forming a pressure region.

  The shape, structure, size, and the like of the pressure member 16 are not particularly limited and may be appropriately selected depending on the purpose, and may be a single member structure. The structure which consists of several members which have different functions like this may be sufficient.

  The endless belt 14 that contacts the fixing roll 12 and sandwiches and conveys the recording medium K to and from the fixing roll 12 is formed in a cylindrical shape as shown in FIG.

  As shown in FIG. 2B, the endless belt 14 is configured, for example, by forming a surface coating layer 14B on the surface of a cylindrical base material layer 14A made of a heat-resistant resin.

  As the material of the cylindrical base material layer 14A, polyimide, polyamide, polyamideimide, polycarbonate, polyester, polyarylate, or the like can be used.

  The surface coating layer 14B is preferably excellent in releasability with respect to the toner, and as the material thereof, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetra Fluororesin such as fluoroethylene-hexafluoropropylene copolymer).

  As described above, the outer peripheral surface of the cylindrical base material layer 14A is covered with the surface coating layer 14B over the entire surface, but the axial direction of the cylindrical base material layer 14A (arrow B in FIG. 2A). At least a part of the end face is also covered with the surface coating layer 14B (direction reference, ie, the same direction as the axial direction of the endless belt 14).

  As shown in FIGS. 2B and 2C, both end surfaces in the axial direction of the cylindrical base material layer 14A are covered with the surface coating layer 14B over the entire region (that is, 100% coating). Although preferable, at least the thickness T2 as the length in the radial direction of the cylindrical base material layer 14A in the surface coating layer 14B covering the axial end surface of the cylindrical base material layer 14A is the cylindrical base material layer 14A. It is essential that the thickness T1 is 20% or more, more preferably 40% or more, and particularly preferably 60% or more.

  When the thickness T2 in the surface coating layer 14B covering the axial end surface of the cylindrical base material layer 14A is less than 20% of the thickness T1 of the cylindrical base material layer 14A, the end face of the cylindrical base material layer 14A Therefore, there is a case where the effect of preventing the end face destruction and wear is weak against the belt meandering generated when the endless belt 14 is used in the fixing device.

The thickness T1 (see FIG. 2B) of the cylindrical base material layer 14A is preferably 40 μm or more and 200 μm or less, more preferably 60 μm or more and 150 μm or less in order to use the endless belt 14 in the fixing device. preferable.
If the thickness T is less than 40 μm, the strength of the endless belt 14 as a whole is weak, so that when used in the fixing device, buckling due to belt meandering is likely to occur, and the endless belt 14 may break. If the thickness exceeds 200 μm, the film thickness of the endless belt 14 becomes thick and the thermal conductivity is poor, so that the energy efficiency is lowered, the flexibility of the endless belt 14 is insufficient, and the peelability of the recording paper is lowered. There may be a problem that the fixing performance deteriorates.

Moreover, it is preferable that thickness T4 (refer FIG. 2 (B)) in the area | region which coat | covers the outer peripheral surface of 14 A of cylindrical base material layers of the surface coating layer 14B is 10 micrometers or more and 60 micrometers or less of the thickness of an endless belt. More preferably, it is 20 μm or more and 50 μm or less.
If the thickness T4 is less than 10 μm of the thickness of the endless belt, when the endless belt 14 is used in the fixing device, the recording paper passes and the surface layer is worn away with a small number of running sheets. There is a case where the moldability is impaired, and there is a problem that image fouling such as poor fixing of the recording paper and toner adhesion occurs. If it exceeds 60 μm, the thermal conductivity of the entire endless belt 14 is lowered and the energy of the fixing device is reduced. There may be a problem that efficiency deteriorates.

  Furthermore, the thickness T3 (see FIG. 2B) of the surface coating layer 14B that covers both ends in the axial direction of the cylindrical base material layer 14A does not particularly limit the content of the present invention. However, it is preferably at least 10 μm or more, more preferably 20 μm or more.

  In the above configuration, in the fixing device 10 according to the present embodiment, by using the endless belt 14, the axial end of the endless belt 14 can be prevented from being broken. A decrease in fixing performance in the fixing device 10 due to breakage can be suppressed.

  That is, in the fixing device 10, as shown in FIG. 1, when the fixing roll 12 is rotationally driven at a predetermined rotational speed in a predetermined direction (arrow E direction in FIG. 1) by driving a motor (not shown), the fixing roll 12 is fixed. Following the rotation of the roll 12, the endless belt 14 rotates (rotates in the counter-rotating direction of the fixing roll 12; the direction of arrow A in FIG. 1).

At this time, if there is a recording medium K holding unfixed toner T in the pressure area N between the fixing roll 12 and the endless belt 14, the recording medium K is taken into the pressure area N and the fixing roll 12 and the endless belt 14.
In the pressure region N between the fixing roll 12 and the endless belt 14, the recording medium K is pressed and heated. As a result, the unfixed toner T is heated and pressed and fixed on the recording medium K.

Here, due to the rotation of the endless belt 14, both end portions in the axial direction of the endless belt 14 come into contact with the guide members 19 and the respective units in the fixing device 10, so that the axial direction of the cylindrical substrate layer 14 </ b> A of the endless belt 14 If the end is worn, the endless belt 14 may be broken.
However, in the endless belt 14 of the present embodiment, as described above, the entire or part of the outer peripheral surface of the cylindrical base material layer 14A is covered with the surface coating layer 14B, and thus the cylindrical base material layer 14A. Abrasion at both ends in the axial direction is suppressed.

  Accordingly, it is possible to suppress wear and fracture of the axial end portion of the endless belt 14 in the fixing device 10. In addition, it is possible to suppress a decrease in fixing performance in the fixing device 10 due to the axial end portion breakage of the endless belt 14.

  The endless belt 14 includes a first coating step in which a film-forming resin solution is applied to the outer peripheral surface of the core body to form a cylindrical resin film on the core body, and a cylindrical resin film formed on the core body And a depth of 20% to 90% of the thickness of the cylindrical resin film along the circumferential direction of the cylindrical resin film at both ends in the axial direction of the cylindrical resin film dried by the drying process. A groove portion forming step for forming a groove portion having a size, and a surface coating resin solution is applied to the outer peripheral surface of the cylindrical resin film on which the groove portion is formed by the groove portion forming step to form a surface coating layer on the cylindrical resin film. A second coating step, a heating and firing step of heating and firing the cylindrical resin film and the surface coating layer, and forming a laminate of the cylindrical base material layer and the surface coating layer on the outer peripheral surface of the core; And a separation step of separating the body.

  Below, the manufacturing method of the endless belt 14 is demonstrated for every process. In addition to this process, various known processes may be provided as appropriate.

-Preparation process-
As shown in FIG. 3, it is preferable to use metals, such as aluminum, stainless steel, nickel, copper, for the core 20 used as the object which apply | coats a film forming resin solution. The core body 20 is cylindrical or columnar, and the axial length of the core body 20 is required to be equal to or longer than the axial length (so-called width) of the target endless belt 14. The axial length of the core body 20 is preferably about 10 to 40% longer than the axial length of the target endless belt 14 in order to secure a margin for the ineffective region generated at both ends in the axial direction. The outer diameter of the core body 20 is matched to the intended inner diameter of the endless belt 14, and the thickness is set to a thickness that can maintain the strength of the core body 20.

  The core body 20 is preferably cylindrical. When the weight of the core body 20 is large, it is preferable to attach holding plates to both ends in the axial direction. The holding plate may have either a structure that sandwiches both ends of the core body 20 or a structure that fits inside the core body 20. Further, either one or both of the core body 20 and the holding plate may have a process such as a step or a cut. The method for attaching the holding plate may be screws or welding.

  Moreover, in order to prevent the film-forming resin solution to be applied from adhering to the surface of the core body 20, it is preferable to impart releasability to the surface of the core body 20. For this purpose, there are methods of plating the surface of the core body 20 with chromium or nickel, coating with a fluororesin or silicone resin, or applying a release agent to the surface.

-First application step-
A film-forming resin solution is applied to the surface of the core body 20.
Examples of the material for the film-forming resin solution include polyimide (hereinafter referred to as PI), polyamideimide (hereinafter referred to as PAI), polycarbonate, polyester, polyamide, polyarylate, and the like. When the material is a thermoplastic resin, the solution is used, and when the material is a non-thermoplastic resin such as PI, the precursor (PI precursor) is used.
Among these materials for the film-forming resin solution, the PI precursor and PAI are preferably used from the viewpoints of strength, shape stability, and the like.

Examples of the PI precursor include those composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA), BPDA and 4,4′-diaminodiphenyl ether. Various known materials such as those consisting of pyromellitic dianhydride (PMDA) and 4,4′-diaminodiphenyl ether can be used. Two or more kinds of PI precursors may be mixed and used, or a plurality of acid or amine monomers may be mixed and copolymerized.
Moreover, what is necessary is just to use various well-known things as PAI.

  Examples of the PI precursor and PAI solvent include aprotic polar solvents such as N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAC), and acetamide, which have low volatility at room temperature.

The mixing ratio, concentration, viscosity, and the like of the film-forming resin solution used for coating are appropriately selected according to the coating method used and the target coating thickness.
Hereinafter, a case where a PI precursor solution having a solid content of 18% and a viscosity of 130 Pa · s is applied by an application method called blade coating will be described with an example.

  As a coating method of the film-forming resin solution on the core body 20, a coating is formed on the surface of the core body 20 while rotating the core body 20 by immersing the core body 20 in the film-forming resin solution and then raising the core body 20. A known method such as a flow coating method in which a resin solution is discharged and a blade coating method in which a film is smoothed with a blade can be employed. In the above-mentioned flow coating method or blade coating method, the coating part is moved horizontally, so that the cylindrical resin film is formed in a spiral shape, but use a slow-drying solvent to slow down the drying of the cylindrical resin film. The seam is naturally smooth.

  In addition, "applying on a core body" means apply | coating to the surface of the outer peripheral surface of the core body 20, and when having a layer in this surface, it means applying to the surface of the layer. Further, “raising the core” is a relative relationship with the liquid level during application, and includes the case of “stopping the core and lowering the coating liquid”.

  In the case of performing application using the flow coating method, a method of smoothing the film-forming resin solution discharged from the nozzle with a blade on the surface of the rotated core body 20 can be mentioned.

  FIG. 3 is a schematic configuration diagram showing a coating apparatus used for the coating method. FIG. 4 is a side view of the main part of the coating apparatus as seen from the axial direction of the core body 20.

As shown in FIGS. 3 and 4, this coating apparatus applies a film-forming resin solution 22 to a cylindrical core body 20 that is an object to be coated, and forms a cylindrical resin film 15 </ b> A using the coating film. It is a coating device. Here, although not shown, the core body 20 is disposed on a pedestal having an arm that is supported so as to be horizontally rotatable (in the direction of arrow C in FIG. 3) via a holding member. Although not shown, the core body 20 is connected to a driving means (rotating means) for rotating the core body 20 through an axis via a holding member.
In addition, a flow-down device 24 is provided around the core body 20 to flow the film-forming resin solution 22 and attach the film-forming resin solution 22 to the core body 20.

  The flow-down device 24 (dispenser) includes, for example, a nozzle 26 that flows down the film-forming resin solution 22 and a container 28 that supplies the film-forming resin solution 22 to the nozzle 26. As the container 28, for example, an apparatus using a meniscus cylinder, a screw or the like is applied. The flow-down device 24 may be configured such that the nozzle 26 and the container 28 are connected by a connecting pipe, and the nozzle 26 and the container 28 are separated and arranged separately, or the nozzle 26 and the container 28 are integrally configured. The form may be sufficient. In the present embodiment, a configuration in which the container 28 and the nozzle 26 are separated and connected via a pump 30 will be described. Further, the flow amount may be controlled by interposing an electromagnetic valve between the nozzle 26 and the container 28, for example.

  Usually, the film-forming resin solution 22 such as a PI precursor solution has a high viscosity of, for example, 1 Pa · s or more and does not flow down naturally. Since the layer thickness of the cylindrical resin film 15A is determined by the discharge amount of the film-forming resin solution 22, the discharge amount must be constant during application. The film forming resin solution may be discharged from the container 28 with pressurized air. However, in order to ensure quantification, the film forming resin solution may be supplied by a pump 30. The pump 30 is preferably a Mono pump capable of discharging a constant amount without interruption.

  The distance between the nozzle 26 and the core body 20 may be arbitrary, but is preferably about 10 to 100 mm so that the falling liquid is not interrupted. If the liquid breaks off, bubbles may be involved.

  A blade 32 is disposed around the core body 20 as a smoothing means for smoothing the film-forming resin solution 22 adhered to the core body 20. The blade 32 abuts against the core body 20 and is brought into pressure contact therewith to smooth the film-forming resin solution 22 adhered to the core body 20, thereby forming a cylindrical resin film 15 </ b> A on the core body 20. The tip of the blade 32 is bent (so as to be) and is pressed against the core body 20.

  Here, as the pressure contact force of the blade 32 to the core body 20, for example, according to the maximum deflection width (for example, 0 to 2 mm) during rotation of the core body 20 having a roundness of 0 to 1 mm, The range is from 0.2N to 4N so that the width can be followed, and the spiral resin film 15A is not subjected to the spiral pattern.

  The flow down device 24 (nozzle 26) and the blade 32 are relatively moved from one end in the axial direction of the core body 20 in accordance with 20 rotations of the core body as the film forming resin solution 22 adheres to and smoothes the core body 20. Move to the other end in the horizontal direction (arrow D direction in FIG. 3). Although not shown, this configuration may be configured to move the flow-down device 24 (nozzle 26) and the blade 32, or may be configured to move the core body 20, and may be configured by a known technique.

By applying the flow-down device 24 (nozzle 26) and the blade 32 in conjunction with each other and moving in a horizontal direction from one end of the core body 20 to the other end, it can be applied to the surface of the core body 20. The moving speed can be said to be the coating speed.
The coating conditions are such that the rotational speed of the core body 20 is 20 to 200 rpm, and the coating speed V is about 0.1 to 2.0 m / min. The higher the solution viscosity, the slower.

  In this embodiment, first, the film forming resin solution 22 is caused to flow down from the nozzle 26 of the flow down device 24 while rotating the core body 20 in the circumferential direction (in the direction of arrow C in FIG. 3), thereby forming a film on the core body 20. A resin solution 22 is adhered. Immediately after this, the blade 32 is moved in the horizontal direction at the abutting position 31 on one end side of the core body 20 and abutted against the core body 20, thereby smoothing the film-forming resin solution 22 attached to the core body 20. Then, each time the core body 20 rotates, the attachment point and the smoothing point (flowing device 24 and blade 32) are moved in the horizontal direction (in the direction of arrow D in FIG. 3) from one end of the core body 20 to the other end.

  Thereafter, immediately before the coating of the film-forming resin solution 22 on the core body 20 is completed, the blade 32 is moved in the horizontal direction and retracted from the core body 20 at the retreat position 34 on the other end side of the core body 20.

  The blade 32 is made of a plate having a thickness of about 0.1 to 1 mm made of a metal such as stainless steel or brass, or an elastic material such as fluororesin or polyethylene. The width needs to be wider than at least the pitch (horizontal movement speed / rotational speed), but even if it is too wide, streaks may remain. While the blade 32 is pressed against the film-forming resin solution 22 and smoothed, the film-forming resin solution exists between the core 20 and the blade 32, so that they do not come into direct contact with each other.

  In this way, the film-forming resin solution 22 is applied to the outer peripheral surface of the core body 20, and a cylindrical resin film 15A as a coating film by the film-forming resin solution is formed.

-Drying process-
In the drying step, as shown in FIG. 5, the cylindrical resin film 15A formed on the core body 20 by the first application step is in a semi-dry state with a solid content of 40% to 60%. dry.

  At the time after the drying, the solvent remains in the cylindrical resin film 15A made of the film-forming resin solution in an amount of 40% to 60% of the total film weight, and the cylindrical resin film 15A still has flexibility. In addition, the strength as the cylindrical base material layer is not maintained, and is held in close contact with the core body 20.

  If the cylindrical resin film 15A is dried until the solid content of the cylindrical resin film 15A is less than 40%, the flexibility of the cylindrical resin film 15A is lost and the film becomes a hard and brittle film, which will be described later. In the groove portion forming step, it becomes difficult to form the groove portion, and problems such as a decrease in adhesion to the surface coating layer 15B occur after the heating and firing step described later.

  In addition, the solid content measurement in the cylindrical resin film 15A used in the above description is about 380 ° C. without performing the groove forming step and the surface layer coating on the core body 20 on which the cylindrical resin film 15A is formed. This is obtained by performing a heat baking treatment for 1 hour. The calculation method is shown below.

With respect to the entire core body 20 on which the cylindrical resin film 15A is formed, the mass a after the drying process (before the firing process), the weight b after the firing process, and the weight c only with the core body 20 are measured. Then
(The solid content of the cylindrical resin film 15A) is represented by (b−c) / (ac) × 100 (%).

  In the drying step, the cylindrical resin film 15A formed on the core body 20 is heated and dried until the semi-dry state is reached. Although the heating and drying conditions in the drying step depend on the type of material (resin) and solvent used for the film-forming resin solution, they are usually in the desired semi-dry state at a temperature of 60 to 120 ° C. for 30 to 120 minutes It is preferable to obtain At that time, the higher the temperature, the shorter the heating time. The temperature may be increased stepwise or at a constant rate over time. It is also effective to apply hot air during heating.

  When dripping occurs in the cylindrical resin film 15A during the drying process, it is effective to make the axial direction of the core body 20 horizontal and rotate it slowly. At this time, the rotational speed of the core body 20 is preferably about 1 to 60 rpm.

-Groove formation process-
In the groove portion forming step, the groove portions 36 are formed along the circumferential direction of the cylindrical resin film 15A at both axial ends of the core body 20 of the cylindrical resin film 15A that has been dried through the drying step.

  The groove portion 36 opens to the front surface side of the cylindrical resin film 15A, assuming that the surface of the cylindrical resin film 15A that contacts the core 20 is the back surface, and as shown in FIG. 7, the shaft of the cylindrical resin film 15A Direction (same direction as the axial direction of the core body 20) in the circumferential direction of the cylindrical resin film 15A along the side edge of the cylindrical resin film 15A at a position moved from the side edge of both ends toward the center by a predetermined distance. It is formed in a straight line toward.

  The groove 36 preferably has a depth dimension of 20% to 90% of the thickness of the cylindrical resin film 15A, more preferably 40% to 90%, and particularly preferably 60% to 90%.

  If the depth dimension of the groove 36 is less than 20% of the thickness of the cylindrical resin film 15A, the range in which both ends of the manufactured endless belt 14 are covered is also less than 20%, and the effect of reinforcing the end is sufficient. The problem of not being able to be obtained may arise. Moreover, the depth dimension of the groove part 36 increases the range in which both ends of the endless belt 14 to be manufactured are covered with the surface layer, and the reinforcing effect is enhanced. There is a high possibility that the cylindrical resin film 15A is completely cut and the surface of the core body 20 is damaged. Therefore, the depth dimension is preferably set to at least 90% or less of the cylindrical resin film 15A.

  The width of the groove part 36 does not particularly limit the content of the present invention, but is preferably 50 μm to 200 μm, and more preferably 70 μm to 120 μm.

  For example, as shown in FIG. 6, the grooves 36 are formed in the cylindrical resin film 15 </ b> A so that the cutting edges of each of the pair of cutting blades 38 come closer to each other from the side edges at both axial ends of the cylindrical resin film 15 </ b> A. It can be formed by rotating the core body 20 in the circumferential direction after making it contact with each position moved by a predetermined distance in the direction.

  The width and depth of the groove 36 are determined when the shape of the cutting edge 38, the size of the cutting edge 38, and the cutting edge of the cutting tool 38 for forming the groove 36 are brought into contact with the outer peripheral surface of the cylindrical resin film 15A. It can be adjusted by adjusting the pressure or the like.

  In the formation of the groove 36, the cylindrical resin film 15A has flexibility because the solvent is contained in the cylindrical resin film 15A after the drying step. is doing. For this reason, the groove part 36 can be formed easily.

-Second coating process-
In the second coating step, the surface coating resin solution is applied to the outer peripheral surface of the cylindrical resin film 15A in which the groove portions 36 are formed in the groove portion forming step, thereby forming the surface coating layer 15B on the cylindrical resin film 15A. .

Such surface coating resin solutions include fluororesins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and the like. Can be used.
Hereinafter, the surface coating resin solution may be referred to as “fluorine resin dispersion” as appropriate.

Such a fluororesin dispersion generally has a solid content adjusted to 40 to 60%, and the viscosity is adjusted with a thickener such as GMC (dimethylcellulose) according to the target coating thickness and coating method. The
Examples of the method for applying the surface coating resin solution include a dip coating method and a spray coating method as shown in FIG. In the dip coating method, the coating viscosity at 25 ° C. is adjusted to 100 cP to 700 cP depending on the target film thickness and coating speed.
In the case of the spray coating method, the coating viscosity at 25 ° C. is adjusted to about 0 to 10 cP, and a method such as overcoating is selected when producing a thick film of 20 μm or more.

  Hereinafter, although the case where the dip coating method is selected as a 2nd application | coating process is demonstrated, this coating method does not limit the content of this invention.

In the second coating step, when the axial direction of the core body 20 is made vertical, as shown in FIG. 8, the end portion of the cylindrical resin film 15A on the lower end side and the exposed portion of the core body 20 are If there is, a covering process is performed on the part (covering region 40).
In addition, even if the surface of the core body 20 is exposed, the portion which becomes the upper end side of the core body 20 is not covered with the surface coating resin solution 42 and is not soaked up to the surface coating resin on the surface of the core body 20. Since the solution 42 does not adhere, the coating process may not be performed. Of course, if that part is covered, it is more reliable.

  Next, as shown in FIG. 8, by immersing the core body 20 in the coating tank 44 containing the surface coating resin solution 42 with the coating processing region 40 side subjected to the coating processing down and the core body 20 vertical, and pulling it up. A surface coating layer 15B made of a fluororesin dispersion film is formed on the cylindrical resin film 15A on the core 20. An annular blower 47 is attached to the upper part of the coating tank 44, and air can be sent to the fluororesin dispersion film coated on the cylindrical resin film 15A.

  The surface coating resin solution 42 may be stored in the application tank 44, but may be supplied from the lower part of the application tank 44, overflowed from the upper part, recovered, and circulated by a pump.

  Here, as the surface coating resin solution 42, the particle diameter of the fluororesin powder is preferably 1 to 20 μm, and the dispersion concentration is preferably about 10 to 70%. As the solvent of the surface coating resin solution 42, water, lower alcohols such as ethanol and butanol, glycols such as ethylene glycol, and esters thereof may be used in combination. When the concentration of the surface coating resin solution 42 increases due to evaporation of the solvent, it may be adjusted by adding a lower alcohol or the like. In addition, a surfactant, a viscosity adjusting agent, and the like may be added to the surface coating resin solution 42.

  Before putting the surface coating resin solution 42 into the coating tank 44, it is preferable to remove bubbles from the surface coating resin solution 42 by defoaming. This is because when the surfactant is added, the surface coating resin solution 42 is liable to foam, and when there are bubbles in the liquid, the coating film is defective. As the defoaming method, there are methods such as depressurization, centrifugal separation, filtration, ultrasonic application and the like in addition to standing. Water has a solubility of about 1.19% by volume of nitrogen and about 0.64% by volume of oxygen at 20 ° C., and gases are dissolved in the fluororesin dispersion, but these dissolved gases are also reduced by reducing the pressure. It is preferable to keep it.

  The pulling speed of the core body 20 from the surface coating resin solution 42 is about 50 to 500 mm / min, although it depends on the desired thickness of the surface coating layer 15B.

  At the time of pulling up, an air flow is applied to the surface coating layer 15B as a coating film of the surface coating resin solution 42 by the annular blower 47 to promote drying of the solvent, but the air flow applied to the surface coating layer 15B is from one direction. Rather, it is better to apply in an annular shape so as to be uniform in the circumferential direction. Examples of such a blower include those described in Japanese Patent No. 2844784 and Japanese Patent No. 2629417.

  After the surface coating layer 15B is formed on the cylindrical resin film 15A by this second coating step, the solvent remaining in the surface coating layer 15B is placed between room temperature and 100 ° C. for 5 to 20 minutes. dry. Before and after this drying, the previously formed coating treatment region 40 is removed.

-Heating and baking process-
Next, in the heating and baking process, the cylindrical resin film 15A and the surface of the core body 20 in which the surface coating layer 15B is laminated on the cylindrical resin film 15A provided with the groove 36 by the second application process. The coating layer 15B is heated and fired simultaneously. Through this heating and firing step, as shown in FIG. 9, a laminate 46 in which the surface coating layer 14B is laminated on the cylindrical base material layer 14A can be formed.

  In this heating and baking step, when a PI precursor is used as the material constituting the cylindrical resin film 15A, it is preferably 250 ° C. to 450 ° C., more preferably about 300 ° C. to 350 ° C. The cylindrical base material layer 14A is formed by a condensation reaction by heating and baking for 60 minutes. At that time, the fluororesin powder constituting the surface coating layer 14B is melted and fired to form the surface coating layer 14B made of fluororesin.

  Here, depending on the type of material constituting the cylindrical resin film 15A, there are solvent volatiles during heating and firing and gases generated during reaction, and these volatiles are present in the cylindrical base material layer 14A after heating and baking. And partial swelling due to gas may occur. This particularly occurs remarkably when the PI precursor is used as a material constituting the cylindrical resin film 15A and the thickness of the cylindrical resin film 15A exceeds 50 μm.

  However, in the present embodiment, since the groove portion 36 is formed on the cylindrical resin film 15A in the groove portion forming step, the volume shrinkage of the cylindrical resin film 15A in the heating and baking step causes the shrinkage to occur as shown in FIG. As described above, the laminated body 46 is torn at the groove portion 36, and gas escape from the inner surface of the laminated body 46 is assisted, thereby suppressing the occurrence of partial swelling to the cylindrical resin film 15A.

-Separation process-
After the heating and firing step, the core body 20 is cooled to room temperature, and then the laminate 46 is removed from the core body 20. At the time of removal, both end portions in the axial direction of the laminated body 46 are separated from the central portion with the groove 36 as a boundary (see FIG. 10B), and this central portion can be obtained as the endless belt 14 of the present embodiment. it can.

  The cylindrical base material layer 14A of the endless belt 14 corresponds to the cylindrical resin film 15A in the laminated state, and the surface coating layer 14B corresponds to the surface coating layer 15B in the laminated body state.

  As described above, according to the method of manufacturing the endless belt 14 of the present embodiment, the groove 36 is provided at both ends in the axial direction of the core body 20 of the cylindrical resin film 15A in the drying step, and the second coating is performed. After applying the surface coating resin solution in the process, the endless belt 14 is manufactured by heating and baking the cylindrical resin film 15A and the surface coating layer 15B in the heating and baking process and separating them from the core body 20.

  For this reason, in the endless belt 14 of the present invention, the outer peripheral surface of the cylindrical base material layer 14A can be covered with the surface coating layer 14B over the entire surface, and the axial direction of the cylindrical base material layer 14A (In FIG. 2A, see the direction of arrow B, that is, the same direction as the axial direction of endless belt 14) At least a part of the end surface may also be covered with surface coating layer 14B.

  Thus, by using the cylindrical base material layer 14A whose axial end face is covered with the surface coating layer 14B, it is possible to suppress wear of the axial end face of the cylindrical base material layer 14A of the endless belt 14. it can.

  Next, the image forming apparatus 50 including the fixing device 10 will be described.

As shown in FIG. 11, the image forming apparatus 50 of the present invention includes a photoconductor 52 that rotates in a predetermined direction (the direction of arrow F in FIG. 11).
A charging device 54, an exposure device 56, a developing device 58, a transfer device 60, and a cleaning member 62 are provided around the photoconductor 52 along the rotation direction of the photoconductor 52.

  The charging device 54 charges the surface of the photoconductor 52 to a predetermined potential. The exposure device 56 forms an electrostatic latent image corresponding to the image data by exposing the surface of the photosensitive member 52 charged by the charging device 54.

The developing device 58 stores a developer containing toner for developing the electrostatic latent image in advance, and supplies the stored developer to the surface of the photoconductor 52 to develop the electrostatic latent image, thereby developing a toner image. Form.
The transfer device 60 transfers the toner image formed on the photoconductor 52 to the recording medium K by sandwiching and conveying the recording medium K with the photoconductor 52.

  The image forming apparatus 50 is provided with a fixing device 10. When the recording medium K onto which the toner image is transferred by the transfer device 60 is transported to the fixing device 10 by a transport mechanism (not shown), the transferred toner image is fixed by the fixing device 10. .

  The cleaning member 62 is provided so as to come into contact with the surface of the photoconductor 52 and removes surface deposits by a frictional force with the surface of the photoconductor 52.

The surface of the photoconductor 52 rotating in a predetermined direction (the direction of arrow F in FIG. 11) is uniformly charged by the charging device 54.
The exposure device 56 forms an electrostatic latent image corresponding to the image data on the surface of the photoreceptor 52 whose surface is uniformly charged. When the area where the electrostatic latent image is formed on the photoconductor 52 reaches the area facing the developing device 58, the electrostatic latent image is developed by the developer stored in the developing device 58. As described above, the electrostatic latent image is developed by the developer, whereby a toner image corresponding to the electrostatic latent image is formed on the photoreceptor 52.

  When the area of the toner image formed on the photoconductor 52 reaches the area facing the transfer device 60 by the rotation of the photoconductor 52, the toner image is transferred to the recording medium K in this area. When the recording medium K is conveyed by a conveyance roll (not shown) and reaches the installation position of the fixing device 10, the toner image transferred onto the recording medium K is heated and pressurized by the fixing device 10 to be recorded. It is fixed on the medium K.

  According to the image forming apparatus 50 of the present embodiment, wear and breakage at both axial ends of the endless belt 14 of the fixing device 10 are suppressed during the fixing process of the toner image onto the recording medium K in the fixing device 10. Further, it is possible to suppress a reduction in fixing processing performance in the fixing device 10 due to wear of the endless belt 14. Accordingly, it is possible to suppress image quality deterioration due to a decrease in fixing processing performance.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

(Preparation of endless belt A1)
-Preparation process-
An aluminum cylinder having an outer diameter of 30 mm, an axial length of 460 mm, and a thickness of 2 mm was prepared. Next, the surface is roughened to Ra 1.0 μm by blasting with spherical alumina particles, and then a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the surface, and then at 300 ° C. for 1 hour. The core body 20 was obtained by baking.

-First application step-
Solid content concentration in which 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine were synthesized in N-methylpyrrolidone as a PI precursor solution as a film-forming resin solution A PI precursor solution having a viscosity of 18% (% by weight, the same applies hereinafter) and a viscosity at 25 ° C. of 130 Pa · s was prepared.

The film-forming resin solution was applied to the surface of the core body 20 using the coating apparatus shown in FIGS. 3 and 4.
Specifically, both ends in the axial direction of the core body 20 are rotatably held, and the axial direction of the core body 20 is adjusted to be a horizontal direction.

  And as shown in FIG. 3, the core 20 was rotated at 20 rpm. The blade 32 is made of polyethylene having a width of 20 mm and a thickness of 1 mm, and has elasticity. This was pressed against the rotating core 20 and the prepared PI precursor solution as the film-forming resin solution 22 was passed through the nozzle 26 having a diameter of 4 mm from the container 28 at an air pressure of 0.4 MPa at 23 ml / min. Extruded at flow rate. When the PI precursor solution passed through the blade 32, the blade 32 was expanded and a gap was formed between the blade 32 and the core body 20. Next, the nozzle 26 and the blade 32 were moved from one end of the core body 20 in the axial direction to the other end at a speed of 360 mm / min. Under this condition, the nozzle 26 and the blade 32 move by 3.0 mm per rotation of the core body 20. In addition, at the time of application | coating, the uncoated part of 5 mm was provided in the axial direction both ends of the core body 20. As shown in FIG.

  By this first application step, a cylindrical resin film 15A having a thickness of 740 μm and an axial length of 450 mm of the core body 20 was formed on the core body 20.

-Drying process-
In the drying step, the cylindrical resin film 15A is dried by putting it in a drying furnace at 120 ° C. for 50 minutes while rotating the core body 20 on which the cylindrical resin film 15A is formed in the first application process at 20 rpm. It was. The solid content of the dried cylindrical resin film 15A was about 52%. The thickness of the cylindrical resin film 15A dried by the drying process was 150 μm.

-Groove formation process-
Next, as shown in FIG. 6, a groove forming jig in which a pair of cutting blades 38 are installed is prepared, and each cutting edge is moved from the side edge of both ends in the axial direction of the cylindrical resin film 15A to the central portion. After contacting each of the positions moved by 49 mm to the center, the core body 20 is rotated in the circumferential direction at a rotation speed of 10 rpm, so that the circumferential direction along the side edges of both axial ends of the cylindrical resin film 15A A pair of groove portions 36 was formed in (see FIG. 7).
The depth dimension of the groove 36 was 90 μm, and the width was 100 μm.

-Second coating process-
Next, as shown in FIG. 8, as a second application step, an adhesive tape (polyester tape) was wound around one end in the axial direction of the core body 20 on which the cylindrical resin film 15A was formed. After the side where the adhesive tape is applied is the lower end and the axial direction of the core body 20 is vertical, PFA paint as a surface coating resin solution (trade name: EN-700CL, concentration: 51.5, manufactured by Mitsui Dupont Chemical Co., Ltd.) %, Viscosity 600 mPa · s) was placed in a coating tank 44 having an inner diameter of 90 mm and a height of 480 mm. An annular blower 47 was attached to the upper part of the coating tank 44.

  In the coating tank 44, the core body 20 is placed vertically with the coating treatment area 40 subjected to the coating treatment on the lower side so as to cover the entire area of the cylindrical resin film 15 </ b> A on the core body 20. It was immersed in the surface coating resin solution. Next, the surface coating layer 15B was formed on the cylindrical resin film 15A by pulling up the core 20 from the surface coating resin solution at a speed of 200 mm / min while applying an air flow.

  After the second coating step, the polyester tape was removed and dried at 80 ° C. for 10 minutes.

-Heating and baking process-
As the heating and baking process, the cylindrical resin film 15A and the surface coating layer 15B formed on the core 20 by the second application process are heated at 380 ° C. for 1 hour, so that the cylindrical resin film 15A and the surface coating layer 15B are heated. The coating layer 15 </ b> B was heated and fired at the same time to form a laminated body composed of the cylindrical base material layer 14 </ b> A and the surface coating layer 14 </ b> B on the core body 20.

  As for the surface coating layer 15B obtained by this heating and firing step, no swelling due to the internal gas was observed. This is because the volumetric shrinkage of the cylindrical resin film 15A occurs during the heating and baking process, and the cylindrical resin film 15A is torn at the groove portion 36, and gas escape from the inside of the cylindrical resin film 15A is assisted from this tear. it is conceivable that.

-Separation process-
In the separation step, the core 20 that had undergone the heating and firing step and the laminate on the core 20 were cooled to room temperature, and then the laminate was removed from the core 20.
At this time, the axial direction both ends and center part of the laminated body were separated by using the groove part 36 as a boundary, and this center part was obtained as an endless belt A1.

  The thickness of the cylindrical base material layer 14A and the surface coating layer 14B in the obtained endless belt A1 and the axial length of the endless belt A1 are each measured using a microscope (trade name VH-800, manufactured by Keyence Corporation). As a result, the following measurement results were obtained.

T1 (thickness of the cylindrical base material layer 14A): 85 μm
T2 (radial length of the cylindrical base material layer 14A of the surface coating layer 14B covering the end of the cylindrical base material layer 14A): 51.0 μm
T3 (length in the axial direction of the cylindrical base material layer 14A of the surface coating layer 14B covering the end of the cylindrical base material layer 14A): 38 μm
T4 (thickness of the surface coating layer 14B covering the circumferential surface of the cylindrical base material layer 14A): 38 μm
・ Axial length of endless belt: 344mm

(Preparation of endless belt A2)
An endless belt A2 was produced in the same manner as the endless belt A1, except that in the groove forming step in the production of the endless belt A1, the depth of the groove 36 was 30 μm and the width was 40 μm.

Regarding the produced endless belt A2, the axial lengths of the T1, T2, T3, T4 and the endless belt were measured in the same manner as the endless belt A1, and the results were as follows.
T1 = 85 μm, T2 = 17.0 μm, T3 = 20 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Preparation of endless belt A3)
An endless belt A3 was produced in the same manner as the endless belt A1, except that in the groove forming step in the production of the endless belt A1, the depth of the groove 36 was 60 μm and the width was 70 μm.

Regarding the produced endless belt A3, the axial lengths of the T1, T2, T3, T4 and the endless belt were measured in the same manner as the endless belt A1, and the results were as follows.
T1 = 85 μm, T2 = 34.0 μm, T3 = 35 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Preparation of endless belt A4)
An endless belt A4 was produced in the same manner as the endless belt A1, except that in the groove forming step in the production of the endless belt A1, the depth of the groove 36 was 120 μm and the width was 125 μm.

Regarding the produced endless belt A4, the axial lengths of the T1, T2, T3, T4 and the endless belt were measured in the same manner as the endless belt A1, and the results were as follows.
T1 = 85 μm, T2 = 68.0 μm, T3 = 38 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Preparation of endless belt A5)
An endless belt A5 was produced in the same manner as the endless belt A1, except that in the groove forming step in the production of the endless belt A1, the depth of the groove 36 was 135 μm and the width was 135 μm.

Regarding the produced endless belt A5, the axial lengths of the T1, T2, T3, T4 and the endless belt were measured in the same manner as the endless belt A1, and the results were as follows.
T1 = 85 μm, T2 = 76.5 μm, T3 = 38 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Preparation of endless belt A6)
An endless belt A6 was produced in the same manner as the endless belt A1, except that in the groove forming step in the production of the endless belt A1, the depth of the groove 36 was 15 μm and the width was 20 μm.

Regarding the produced endless belt A6, the axial lengths of the T1, T2, T3, T4 and the endless belt were measured in the same manner as the endless belt A1, and were as follows.
T1 = 85 μm, T2 = 76.5 μm, T3 = 10 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Preparation of endless belt A7)
In the groove portion forming step in the production of the endless belt A1, the groove portion 36 is not formed, and both end portions in the axial direction of the laminate separated in the separation step are cut by using a belt cutting jig. An endless belt A7 was produced in the same manner as the endless belt A1 except that it was produced.

Regarding the produced endless belt A7, the axial lengths of T1, T4 and the endless belt were measured in the same manner as the endless belt A1, and the results were as follows.
T1 = 85 μm, T4 = 38 μm, axial length of endless belt = 344 mm
The measurement results are also shown in Table 1.

(Example 1)
The produced endless belt A1 was installed in the fixing device instead of the endless belt of the fixing device of DocuCenterColor400CP (Fuji Xerox Co., Ltd.), and the strength test of the endless belt A1 was performed.

  Prior to the strength test, first, with respect to the pressure member 16 provided in the fixing device, the pressure in the width direction of the endless belt A1 in the contact area between the endless belt A1 and the fixing roll 12 is not uniform. Pressure adjustment was performed. Specifically, in this contact region, a load of 16.5 kg is applied from one end to the other end of the endless belt A1 in the axial direction by a biasing member such as a spring so that a load is evenly applied. In this example, a load of 15 kg was applied to the region from one end of the endless belt A1 in the axial direction to the central portion in this contact region, and a load of 18 kg was applied from the other end in the axial direction to the central portion. .

With the fixing device adjusted as described above, the fixing roll and the endless belt were rotationally driven under the conditions of a process speed (conveying speed of the fixing roll and endless belt) of 208 mm / s and a surface temperature of the fixing roll of 175 ° C. Since the pressure distribution in the contact area between the endless belt and the endless belt is nonuniform, meandering of the endless belt A1 was observed. Further, when the postcard paper (100 mm × 148 mm, paper weight 186 (g / m ² )) is nipped and conveyed between the fixing roll and the endless belt, each time the postcard paper is nipped, the end of the endless belt A1 is moved in the axial direction. It was observed that a part of the region contacts a guide member that guides the rotation of the endless belt A1.

  Using the fixing device under such conditions, 3500 postcard sheets are continuously passed between the fixing roll and the endless belt A1, and the shaft of the endless belt A1 is passed each time 500 postcard sheets pass. The strength evaluation of the direction both ends was performed. The evaluation results are shown in FIG.

In FIG. 12, the strength evaluation standard is the measurement of the depth of the largest crack among the cracks generated on the end face in the axial direction of the endless belt 14 using a precision caliper (manufactured by Mitutoyo, model number CD-20C). According to the measurement results, six stages of evaluation were performed. The evaluation criteria are shown below.
-G0: No crack occurred at the end.
G1: Crack depth of less than 0.5 mm G2: Crack depth of 0.5 mm or more and less than 1.0 mm G3: Crack depth of 1.0 mm or more and less than 2.0 mm G4: Crack depth 0 mm or more and less than 3.0 mm ・ G5: Crack depth of 3.0 mm or more

In the above evaluation, the “crack depth dimension” means that the axial end of the endless belt 14 before passing paper is referred to as a reference position (hereinafter referred to as a reference position 14E (initial)). The axial length from the initial) to the point where the crack has most advanced is shown.
As belt wear and breakage progress, the end of the endless belt 14 is scraped, and the exact position of the reference position 14E (initial) of the endless belt 14 before paper passing becomes unclear. Therefore, before the sheet is passed, the surface coating layer is marked at a position 20 mm from the reference position 14E (initial), and from this marking position, the relative distance between the reference position 14E (initial) and the point where the crack has progressed most. By measuring, the "crack depth dimension" was obtained.

(Examples 2 to 6, Comparative Example 1)
Instead of the endless belt A1 used in the first embodiment, the endless belt A2 is used in the second embodiment, the endless belt A3 is used in the third embodiment, and the endless belt A4 is used in the fourth embodiment. The strength was evaluated in the same manner as in Example 1, with Example 5 using the belt A5, Example 6 using the endless belt A6, and Comparative Example 1 using the endless belt A7. The evaluation results are shown in FIG.

  As shown in Table 1 and FIG. 12, in Comparative Example 1 using the endless belt A7 produced without forming the groove 36 in the cylindrical resin film 15A, the endless belt A1 having the groove 36 formed in the cylindrical resin film 15A. Compared with Examples 1 to 6 using the endless belt A6, the endless belt cracked before 500 sheets of postcard paper passed, and when 1500 postcard sheets passed, the crack was 3. It spreads to 0 mm or more.

On the other hand, in Examples 1 to 6 using the endless belt A1 to the endless belt A6 in which the groove 36 is formed in the cylindrical resin film 15A, a crack having a depth of less than 0.5 mm was observed in Comparative Example 1. The occurrence of cracks having a depth of less than 0.5 mm and less than 0.5 mm and less than 1.0 mm was observed only after passing twice or more sheets of postcard paper.
Similarly, in Examples 1 to 6 using the endless belt A1 to the endless belt A6 in which the groove portion 36 is formed in the cylindrical resin film 15A, a crack having a depth of 3.0 mm or more was observed in Comparative Example 1. A crack having a depth of less than 3.0 mm was observed only after 1.6 times or more of the postcard paper was passed through compared to 1500 postcards.

  Therefore, the endless belt A1 to endless belt A6 used in Examples 1 to 6 are configured such that at least a part of both end surfaces in the axial direction of the cylindrical base material layer 14A are covered with the surface coating layer 14B. Therefore, it can be said that wear and cracks at both ends in the axial direction can be suppressed.

  Further, of the endless belt A1 to endless belt A6 used in Examples 1 to 6, Example 100, Example 4, and Example 5 in which the value of 100 × T2 / T1 (%) is 60% or more. The endless belt A1, the endless belt A4, and the endless belt A5 used in Example 2 are the endless belts used in Example 2, Example 3, and Example 6 in which the value of 100 × T2 / T1 (%) is less than 60%. Compared to A2, endless belt A3, and endless belt A6, the depth of cracks observed was less than 2.0 mm even when the postcard paper passing amount was 3000 sheets. For this reason, it can be said that the larger the region of the surface coating layer 14B covering the cylindrical base material layer 14A, the more the cracks and breaks of the end portions in the axial direction of the endless belt can be suppressed.

  Further, the endless belt A6 used in Example 6 has a low value of 100 × T2 / T1 (%) of 10%, and the postcard paper passing amount is a depth of 0.5 mm or more and less than 1.0 mm when 1000 sheets are passed. A crack has occurred, and it is determined that the effect of reinforcing the belt end is less than that of the endless belts A1 to A5 of the other embodiments.

(Example 8)
In the production of the endless belt A1, ten aluminum cylinders were prepared, and the production of the endless belt A1 was repeated 20 times using each of the prepared aluminum cylinders using the method for producing the endless belt A1. . This produced 20 endless belts A1 for each aluminum cylinder (total of 200).

  Of the 200 endless belts A1 produced, 10 endless belts A1 produced for the first time, 10 endless belts A1 produced for the 10th time, and 10 endless belts A1 produced for the 20th time, Each outer diameter was measured using a laser outer diameter measuring device (trade name: LS-3060, manufactured by Keyence Corporation), and for each group of endless belt A1 produced each time, the average value of the outer diameter, the standard deviation, Sought. The measurement results are shown in Table 2.

(Comparative Example 2)
In the production of the endless belt A7, ten aluminum cylinders were prepared, and the production of the endless belt A7 was repeated 20 times using each of the prepared aluminum cylinders, using the method for producing the endless belt A7. . This produced 20 endless belts A7 for each aluminum cylinder (200 in total).

  Of the 200 endless belts A7 produced, 10 endless belts A7 produced the first time, 10 endless belts A7 produced the 10th time, and 10 endless belts A7 produced the 20th time, Each outer diameter was measured using a laser outer diameter measuring device (manufactured by Keyence Corporation, trade name: LS-3060), and for each group of endless belts A7 produced each time, the average value of the outer diameter, the standard deviation, Sought. The measurement results are shown in Table 2.

As shown in Table 2, it can be seen that the endless belt A1 measured in Example 7 has a smaller variation in the outer diameter difference at the number of repeated productions than the endless belt A7 measured in Comparative Example 2. . Further, it can be seen that the change rate of the outer diameter value of the endless belt due to the increase in the number of manufacturing repetitions is larger in the endless belt A7 measured in Comparative Example 2 than in the endless belt A1 measured in Example 7. .
From this, it can be said that by using the endless belt manufacturing method of the present invention, it is possible to suppress wear and breakage of the axial end portion of the endless belt and to provide an endless belt with high dimensional accuracy.

1 is a schematic configuration diagram illustrating an example of a fixing device of the present invention. It is a schematic diagram which shows an example of the endless belt of this invention, (A) is an external view, (B) is a schematic diagram which shows the II 'cross section of (A), (C) is an endless belt. It is a schematic diagram which shows an example of the form which looked at the axial direction end surface from the axial direction. It is a schematic block diagram which shows an example of the coating device used in the 1st coating process in manufacture of the endless belt of this invention. It is sectional drawing which looked at the principal part of the coating device used in the 1st coating process in manufacture of the endless belt of this invention from the axial direction of the core. It is a schematic diagram which shows the core state of a 1st application | coating process, and is a schematic diagram which shows the state by which the cylindrical resin film was formed on the core. It is a schematic diagram which shows a groove part formation process. It is a schematic diagram which shows the groove part formed in the cylindrical resin film. It is a schematic diagram which shows an example of the coating device used in a 2nd coating process. It is a schematic diagram which shows the state by which the laminated body was formed on the core by the heat-firing process. (A) is a schematic diagram which shows the state which the laminated body fractured | ruptured by making a groove part into a boundary, (B) is a schematic diagram which shows the state by which the axial direction both ends of the laminated body were isolate | separated from the center part by the isolation | separation process. It is. 1 is a schematic diagram illustrating an image forming apparatus of the present invention. It is a diagram which shows the fracture | rupture state of the endless belt end surface in an Example and a comparative example, and is a diagram which shows the relationship between a fracture | rupture evaluation value and the postcard paper passage amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing device 12 Fixing roll 14A Cylindrical base material layer 14B Surface coating layer 14 Endless belt 15A Cylindrical resin film 15B Surface coating layer 20 Core body 36 Groove part 50 Image forming apparatus 52 Photoconductor 54 Charging apparatus 56 Exposure apparatus 58 Developing apparatus 60 Transfer apparatus

Claims (4)

  A cylindrical base material layer, and a surface coating layer laminated on an outer peripheral surface of the cylindrical base material layer, wherein at least a part of both axial end faces of the cylindrical base material layer is formed by the surface coating layer. An endless belt characterized by being coated. A first application step of applying a film-forming resin solution on the outer peripheral surface of the core body to form a cylindrical resin film on the core body;
A drying step of drying the cylindrical resin film formed on the core;
Grooves having a depth dimension of 20% or more and 90% or less of the thickness of the cylindrical resin film along the circumferential direction of the cylindrical resin film at both ends in the axial direction of the cylindrical resin film dried by the drying step. A groove forming step to be formed;
A second application step of forming a surface coating layer by applying a surface coating resin solution to an outer peripheral surface of the cylindrical resin film in which the groove portion is formed by the groove portion formation step;
A heating and firing step of heating and firing the cylindrical resin film and the surface coating layer, and forming a laminate of the cylindrical base material layer and the surface coating layer on an outer peripheral surface of the core;
A separation step of separating the laminate and the core;
A process for producing an endless belt. A fixing member disposed rotatably;
A cylindrical base material layer, and a surface coating layer laminated on an outer peripheral surface of the cylindrical base material layer, wherein at least a part of both axial end faces of the cylindrical base material layer is formed by the surface coating layer. An endless belt that is coated and sandwiches and conveys a recording medium with the fixing member;
A pressure unit that is disposed on an inner peripheral side of the endless belt and applies pressure to the fixing member via the endless belt or the endless belt and the recording medium;
A fixing device comprising: An image carrier,
Latent image forming means for forming an electrostatic latent image on the image carrier;
Developing means for developing the electrostatic latent image with toner to form a toner image on the image carrier;
Transfer means for transferring a toner image on the image carrier to a recording medium;
A fixing member disposed rotatably; a cylindrical base material layer; and a surface covering layer laminated on an outer peripheral surface of the cylindrical base material layer, and at least axial end faces of the cylindrical base material layer. A part of which is covered with the surface coating layer, disposed on the inner peripheral side of the endless belt, and sandwiching and transporting a recording medium between the fixing member, the endless belt, the endless belt, and the endless belt; A pressure unit that applies pressure to the fixing member via a recording medium, and a fixing device that fixes the toner image on the recording medium, onto which the toner image has been transferred by the transfer unit, on the recording medium;
An image forming apparatus comprising:

Images